/* $NetBSD: if_wg.c,v 1.135 2024/12/27 16:42:28 riastradh Exp $ */

/* $NetBSD: if_wg.c,v 1.135 2024/12/27 16:42:28 riastradh Exp $ */

/*
* Copyright (C) Ryota Ozaki <[email protected]>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

/*
* This network interface aims to implement the WireGuard protocol.
* The implementation is based on the paper of WireGuard as of
* 2018-06-30 [1]. The paper is referred in the source code with label
* [W]. Also the specification of the Noise protocol framework as of
* 2018-07-11 [2] is referred with label [N].
*
* [1] https://www.wireguard.com/papers/wireguard.pdf
* https://web.archive.org/web/20180805103233/https://www.wireguard.com/papers/wireguard.pdf
* [2] http://noiseprotocol.org/noise.pdf
* https://web.archive.org/web/20180727193154/https://noiseprotocol.org/noise.pdf
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: if_wg.c,v 1.135 2024/12/27 16:42:28 riastradh Exp $");

#ifdef _KERNEL_OPT
#include "opt_altq_enabled.h"
#include "opt_inet.h"
#endif

#include <sys/param.h>
#include <sys/types.h>

#include <sys/atomic.h>
#include <sys/callout.h>
#include <sys/cprng.h>
#include <sys/cpu.h>
#include <sys/device.h>
#include <sys/domain.h>
#include <sys/errno.h>
#include <sys/intr.h>
#include <sys/ioctl.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/once.h>
#include <sys/percpu.h>
#include <sys/pserialize.h>
#include <sys/psref.h>
#include <sys/queue.h>
#include <sys/rwlock.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sockio.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#include <sys/thmap.h>
#include <sys/threadpool.h>
#include <sys/time.h>
#include <sys/timespec.h>
#include <sys/workqueue.h>

#include <lib/libkern/libkern.h>

#include <net/bpf.h>
#include <net/if.h>
#include <net/if_types.h>
#include <net/if_wg.h>
#include <net/pktqueue.h>
#include <net/route.h>

#ifdef INET
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#endif /* INET */

#ifdef INET6
#include <netinet/ip6.h>
#include <netinet6/in6_pcb.h>
#include <netinet6/in6_var.h>
#include <netinet6/ip6_var.h>
#include <netinet6/udp6_var.h>
#endif /* INET6 */

#include <prop/proplib.h>

#include <crypto/blake2/blake2s.h>
#include <crypto/sodium/crypto_aead_chacha20poly1305.h>
#include <crypto/sodium/crypto_aead_xchacha20poly1305.h>
#include <crypto/sodium/crypto_scalarmult.h>

#include "ioconf.h"

#ifdef WG_RUMPKERNEL
#include "wg_user.h"
#endif

#ifndef time_uptime32
#define time_uptime32 ((uint32_t)time_uptime)
#endif

/*
* Data structures
* - struct wg_softc is an instance of wg interfaces
* - It has a list of peers (struct wg_peer)
* - It has a threadpool job that sends/receives handshake messages and
* runs event handlers
* - It has its own two routing tables: one is for IPv4 and the other IPv6
* - struct wg_peer is a representative of a peer
* - It has a struct work to handle handshakes and timer tasks
* - It has a pair of session instances (struct wg_session)
* - It has a pair of endpoint instances (struct wg_sockaddr)
* - Normally one endpoint is used and the second one is used only on
* a peer migration (a change of peer's IP address)
* - It has a list of IP addresses and sub networks called allowedips
* (struct wg_allowedip)
* - A packets sent over a session is allowed if its destination matches
* any IP addresses or sub networks of the list
* - struct wg_session represents a session of a secure tunnel with a peer
* - Two instances of sessions belong to a peer; a stable session and a
* unstable session
* - A handshake process of a session always starts with a unstable instance
* - Once a session is established, its instance becomes stable and the
* other becomes unstable instead
* - Data messages are always sent via a stable session
*
* Locking notes:
* - Each wg has a mutex(9) wg_lock, and a rwlock(9) wg_rwlock
* - Changes to the peer list are serialized by wg_lock
* - The peer list may be read with pserialize(9) and psref(9)
* - The rwlock (wg_rwlock) protects the routing tables (wg_rtable_ipv[46])
* => XXX replace by pserialize when routing table is psz-safe
* - Each peer (struct wg_peer, wgp) has a mutex wgp_lock, which can be taken
* only in thread context and serializes:
* - the stable and unstable session pointers
* - all unstable session state
* - Packet processing may be done in softint context:
* - The stable session can be read under pserialize(9) or psref(9)
* - The stable session is always ESTABLISHED
* - On a session swap, we must wait for all readers to release a
* reference to a stable session before changing wgs_state and
* session states
* - Lock order: wg_lock -> wgp_lock
*/

#define WGLOG(level, fmt, args...) \
log(level, "%s: " fmt, __func__, ##args)

#define WG_DEBUG

/* Debug options */
#ifdef WG_DEBUG
/* Output debug logs */
#ifndef WG_DEBUG_LOG
#define WG_DEBUG_LOG
#endif
/* Output trace logs */
#ifndef WG_DEBUG_TRACE
#define WG_DEBUG_TRACE
#endif
/* Output hash values, etc. */
#ifndef WG_DEBUG_DUMP
#define WG_DEBUG_DUMP
#endif
/* Make some internal parameters configurable for testing and debugging */
#ifndef WG_DEBUG_PARAMS
#define WG_DEBUG_PARAMS
#endif
#endif /* WG_DEBUG */

#ifndef WG_DEBUG
# if defined(WG_DEBUG_LOG) || defined(WG_DEBUG_TRACE) || \
defined(WG_DEBUG_DUMP) || defined(WG_DEBUG_PARAMS)
# define WG_DEBUG
# endif
#endif

#ifdef WG_DEBUG
int wg_debug;
#define WG_DEBUG_FLAGS_LOG 1
#define WG_DEBUG_FLAGS_TRACE 2
#define WG_DEBUG_FLAGS_DUMP 4
#endif

#ifdef WG_DEBUG_TRACE
#define WG_TRACE(msg) do { \
if (wg_debug & WG_DEBUG_FLAGS_TRACE) \
log(LOG_DEBUG, "%s:%d: %s\n", __func__, __LINE__, (msg)); \
} while (0)
#else
#define WG_TRACE(msg) __nothing
#endif

#ifdef WG_DEBUG_LOG
#define WG_DLOG(fmt, args...) do { \
if (wg_debug & WG_DEBUG_FLAGS_LOG) \
log(LOG_DEBUG, "%s: " fmt, __func__, ##args); \
} while (0)
#else
#define WG_DLOG(fmt, args...) __nothing
#endif

#define WG_LOG_RATECHECK(wgprc, level, fmt, args...) do { \
if (ppsratecheck(&(wgprc)->wgprc_lasttime, \
&(wgprc)->wgprc_curpps, 1)) { \
log(level, fmt, ##args); \
} \
} while (0)

#ifdef WG_DEBUG_PARAMS
static bool wg_force_underload = false;
#endif

#ifdef WG_DEBUG_DUMP

static char enomem[10] = "[enomem]";

#define MAX_HDUMP_LEN 10000 /* large enough */

/*
* gethexdump(p, n)
*
* Allocate a string returning a hexdump of bytes p[0..n),
* truncated to MAX_HDUMP_LEN. Must be freed with puthexdump.
*
* We use this instead of libkern hexdump() because the result is
* logged with log(LOG_DEBUG, ...), which puts a priority tag on
* every message, so it can't be done incrementally.
*/
static char *
gethexdump(const void *vp, size_t n)
{
char *buf;
const uint8_t *p = vp;
size_t i, alloc;

alloc = n;
if (n > MAX_HDUMP_LEN)
alloc = MAX_HDUMP_LEN;
buf = kmem_alloc(3*alloc + 5, KM_NOSLEEP);
if (buf == NULL)
return enomem;
for (i = 0; i < alloc; i++)
snprintf(buf + 3*i, 3 + 1, " %02hhx", p[i]);
if (alloc != n)
snprintf(buf + 3*i, 4 + 1, " ...");
return buf;
}

static void
puthexdump(char *buf, const void *p, size_t n)
{

if (buf == NULL || buf == enomem)
return;
if (n > MAX_HDUMP_LEN)
n = MAX_HDUMP_LEN;
kmem_free(buf, 3*n + 5);
}

#ifdef WG_RUMPKERNEL
static void
wg_dump_buf(const char *func, const char *buf, const size_t size)
{
if ((wg_debug & WG_DEBUG_FLAGS_DUMP) == 0)
return;

char *hex = gethexdump(buf, size);

log(LOG_DEBUG, "%s: %s\n", func, hex);
puthexdump(hex, buf, size);
}
#endif

static void
wg_dump_hash(const uint8_t *func, const uint8_t *name, const uint8_t *hash,
const size_t size)
{
if ((wg_debug & WG_DEBUG_FLAGS_DUMP) == 0)
return;

char *hex = gethexdump(hash, size);

log(LOG_DEBUG, "%s: %s: %s\n", func, name, hex);
puthexdump(hex, hash, size);
}

#define WG_DUMP_HASH(name, hash) \
wg_dump_hash(__func__, name, hash, WG_HASH_LEN)
#define WG_DUMP_HASH48(name, hash) \
wg_dump_hash(__func__, name, hash, 48)
#define WG_DUMP_BUF(buf, size) \
wg_dump_buf(__func__, buf, size)
#else
#define WG_DUMP_HASH(name, hash) __nothing
#define WG_DUMP_HASH48(name, hash) __nothing
#define WG_DUMP_BUF(buf, size) __nothing
#endif /* WG_DEBUG_DUMP */

/* chosen somewhat arbitrarily -- fits in signed 16 bits NUL-terminated */
#define WG_MAX_PROPLEN 32766

#define WG_MTU 1420
#define WG_ALLOWEDIPS 16

#define CURVE25519_KEY_LEN 32
#define TAI64N_LEN (sizeof(uint32_t) * 3)
#define POLY1305_AUTHTAG_LEN 16
#define HMAC_BLOCK_LEN 64

/* [N] 4.1: "DHLEN must be 32 or greater." WireGuard chooses 32. */
/* [N] 4.3: Hash functions */
#define NOISE_DHLEN 32
/* [N] 4.3: "Must be 32 or 64." WireGuard chooses 32. */
#define NOISE_HASHLEN 32
#define NOISE_BLOCKLEN 64
#define NOISE_HKDF_OUTPUT_LEN NOISE_HASHLEN
/* [N] 5.1: "k" */
#define NOISE_CIPHER_KEY_LEN 32
/*
* [N] 9.2: "psk"
* "... psk is a 32-byte secret value provided by the application."
*/
#define NOISE_PRESHARED_KEY_LEN 32

#define WG_STATIC_KEY_LEN CURVE25519_KEY_LEN
#define WG_TIMESTAMP_LEN TAI64N_LEN

#define WG_PRESHARED_KEY_LEN NOISE_PRESHARED_KEY_LEN

#define WG_COOKIE_LEN 16
#define WG_MAC_LEN 16
#define WG_COOKIESECRET_LEN 32

#define WG_EPHEMERAL_KEY_LEN CURVE25519_KEY_LEN
/* [N] 5.2: "ck: A chaining key of HASHLEN bytes" */
#define WG_CHAINING_KEY_LEN NOISE_HASHLEN
/* [N] 5.2: "h: A hash output of HASHLEN bytes" */
#define WG_HASH_LEN NOISE_HASHLEN
#define WG_CIPHER_KEY_LEN NOISE_CIPHER_KEY_LEN
#define WG_DH_OUTPUT_LEN NOISE_DHLEN
#define WG_KDF_OUTPUT_LEN NOISE_HKDF_OUTPUT_LEN
#define WG_AUTHTAG_LEN POLY1305_AUTHTAG_LEN
#define WG_DATA_KEY_LEN 32
#define WG_SALT_LEN 24

/*
* The protocol messages
*/
struct wg_msg {
uint32_t wgm_type;
} __packed;

/* [W] 5.4.2 First Message: Initiator to Responder */
struct wg_msg_init {
uint32_t wgmi_type;
uint32_t wgmi_sender;
uint8_t wgmi_ephemeral[WG_EPHEMERAL_KEY_LEN];
uint8_t wgmi_static[WG_STATIC_KEY_LEN + WG_AUTHTAG_LEN];
uint8_t wgmi_timestamp[WG_TIMESTAMP_LEN + WG_AUTHTAG_LEN];
uint8_t wgmi_mac1[WG_MAC_LEN];
uint8_t wgmi_mac2[WG_MAC_LEN];
} __packed;

/* [W] 5.4.3 Second Message: Responder to Initiator */
struct wg_msg_resp {
uint32_t wgmr_type;
uint32_t wgmr_sender;
uint32_t wgmr_receiver;
uint8_t wgmr_ephemeral[WG_EPHEMERAL_KEY_LEN];
uint8_t wgmr_empty[0 + WG_AUTHTAG_LEN];
uint8_t wgmr_mac1[WG_MAC_LEN];
uint8_t wgmr_mac2[WG_MAC_LEN];
} __packed;

/* [W] 5.4.6 Subsequent Messages: Transport Data Messages */
struct wg_msg_data {
uint32_t wgmd_type;
uint32_t wgmd_receiver;
uint64_t wgmd_counter;
uint32_t wgmd_packet[];
} __packed;

/* [W] 5.4.7 Under Load: Cookie Reply Message */
struct wg_msg_cookie {
uint32_t wgmc_type;
uint32_t wgmc_receiver;
uint8_t wgmc_salt[WG_SALT_LEN];
uint8_t wgmc_cookie[WG_COOKIE_LEN + WG_AUTHTAG_LEN];
} __packed;

#define WG_MSG_TYPE_INIT 1
#define WG_MSG_TYPE_RESP 2
#define WG_MSG_TYPE_COOKIE 3
#define WG_MSG_TYPE_DATA 4
#define WG_MSG_TYPE_MAX WG_MSG_TYPE_DATA

/* Sliding windows */

#define SLIWIN_BITS 2048u
#define SLIWIN_TYPE uint32_t
#define SLIWIN_BPW (NBBY*sizeof(SLIWIN_TYPE))
#define SLIWIN_WORDS howmany(SLIWIN_BITS, SLIWIN_BPW)
#define SLIWIN_NPKT (SLIWIN_BITS - NBBY*sizeof(SLIWIN_TYPE))

struct sliwin {
SLIWIN_TYPE B[SLIWIN_WORDS];
uint64_t T;
};

/*
* sliwin_reset(W)
*
* Reset sliding window state to a blank history with no observed
* sequence numbers.
*
* Caller must have exclusive access to W.
*/
static void
sliwin_reset(struct sliwin *W)
{

memset(W, 0, sizeof(*W));
}

/*
* sliwin_check_fast(W, S)
*
* Do a fast check of the sliding window W to validate sequence
* number S. No state is recorded. Return 0 on accept, nonzero
* error code on reject.
*
* May be called concurrently with other calls to
* sliwin_check_fast and sliwin_update.
*/
static int
sliwin_check_fast(const volatile struct sliwin *W, uint64_t S)
{

/*
* If it's more than one window older than the highest sequence
* number we've seen, reject.
*/
#ifdef __HAVE_ATOMIC64_LOADSTORE
if (S + SLIWIN_NPKT < atomic_load_relaxed(&W->T))
return EAUTH;
#endif

/*
* Otherwise, we need to take the lock to decide, so don't
* reject just yet. Caller must serialize a call to
* sliwin_update in this case.
*/
return 0;
}

/*
* sliwin_update(W, S)
*
* Check the sliding window W to validate sequence number S, and
* if accepted, update it to reflect having observed S. Return 0
* on accept, nonzero error code on reject.
*
* May be called concurrently with other calls to
* sliwin_check_fast, but caller must exclude other calls to
* sliwin_update.
*/
static int
sliwin_update(struct sliwin *W, uint64_t S)
{
unsigned word, bit;

/*
* If it's more than one window older than the highest sequence
* number we've seen, reject.
*/
if (S + SLIWIN_NPKT < W->T)
return EAUTH;

/*
* If it's higher than the highest sequence number we've seen,
* advance the window.
*/
if (S > W->T) {
uint64_t i = W->T / SLIWIN_BPW;
uint64_t j = S / SLIWIN_BPW;
unsigned k;

for (k = 0; k < MIN(j - i, SLIWIN_WORDS); k++)
W->B[(i + k + 1) % SLIWIN_WORDS] = 0;
#ifdef __HAVE_ATOMIC64_LOADSTORE
atomic_store_relaxed(&W->T, S);
#else
W->T = S;
#endif
}

/* Test and set the bit -- if already set, reject. */
word = (S / SLIWIN_BPW) % SLIWIN_WORDS;
bit = S % SLIWIN_BPW;
if (W->B[word] & (1UL << bit))
return EAUTH;
W->B[word] |= 1U << bit;

/* Accept! */
return 0;
}

struct wg_session {
struct wg_peer *wgs_peer;
struct psref_target
wgs_psref;

volatile int wgs_state;
#define WGS_STATE_UNKNOWN 0
#define WGS_STATE_INIT_ACTIVE 1
#define WGS_STATE_INIT_PASSIVE 2
#define WGS_STATE_ESTABLISHED 3
#define WGS_STATE_DESTROYING 4

uint32_t wgs_time_established;
volatile uint32_t
wgs_time_last_data_sent;
volatile bool wgs_force_rekey;
bool wgs_is_initiator;

uint32_t wgs_local_index;
uint32_t wgs_remote_index;
#ifdef __HAVE_ATOMIC64_LOADSTORE
volatile uint64_t
wgs_send_counter;
#else
kmutex_t wgs_send_counter_lock;
uint64_t wgs_send_counter;
#endif

struct {
kmutex_t lock;
struct sliwin window;
} *wgs_recvwin;

uint8_t wgs_handshake_hash[WG_HASH_LEN];
uint8_t wgs_chaining_key[WG_CHAINING_KEY_LEN];
uint8_t wgs_ephemeral_key_pub[WG_EPHEMERAL_KEY_LEN];
uint8_t wgs_ephemeral_key_priv[WG_EPHEMERAL_KEY_LEN];
uint8_t wgs_ephemeral_key_peer[WG_EPHEMERAL_KEY_LEN];
uint8_t wgs_tkey_send[WG_DATA_KEY_LEN];
uint8_t wgs_tkey_recv[WG_DATA_KEY_LEN];
};

struct wg_sockaddr {
union {
struct sockaddr_storage _ss;
struct sockaddr _sa;
struct sockaddr_in _sin;
struct sockaddr_in6 _sin6;
};
struct psref_target wgsa_psref;
};

#define wgsatoss(wgsa) (&(wgsa)->_ss)
#define wgsatosa(wgsa) (&(wgsa)->_sa)
#define wgsatosin(wgsa) (&(wgsa)->_sin)
#define wgsatosin6(wgsa) (&(wgsa)->_sin6)

#define wgsa_family(wgsa) (wgsatosa(wgsa)->sa_family)

struct wg_peer;
struct wg_allowedip {
struct radix_node wga_nodes[2];
struct wg_sockaddr _wga_sa_addr;
struct wg_sockaddr _wga_sa_mask;
#define wga_sa_addr _wga_sa_addr._sa
#define wga_sa_mask _wga_sa_mask._sa

int wga_family;
uint8_t wga_cidr;
union {
struct in_addr _ip4;
struct in6_addr _ip6;
} wga_addr;
#define wga_addr4 wga_addr._ip4
#define wga_addr6 wga_addr._ip6

struct wg_peer *wga_peer;
};

typedef uint8_t wg_timestamp_t[WG_TIMESTAMP_LEN];

struct wg_ppsratecheck {
struct timeval wgprc_lasttime;
int wgprc_curpps;
};

struct wg_softc;
struct wg_peer {
struct wg_softc *wgp_sc;
char wgp_name[WG_PEER_NAME_MAXLEN + 1];
struct pslist_entry wgp_peerlist_entry;
pserialize_t wgp_psz;
struct psref_target wgp_psref;
kmutex_t *wgp_lock;
kmutex_t *wgp_intr_lock;

uint8_t wgp_pubkey[WG_STATIC_KEY_LEN];
struct wg_sockaddr *volatile wgp_endpoint;
struct wg_sockaddr *wgp_endpoint0;
volatile unsigned wgp_endpoint_changing;
volatile bool wgp_endpoint_available;

/* The preshared key (optional) */
uint8_t wgp_psk[WG_PRESHARED_KEY_LEN];

struct wg_session *volatile wgp_session_stable;
struct wg_session *wgp_session_unstable;

/* first outgoing packet awaiting session initiation */
struct mbuf *volatile wgp_pending;

/* timestamp in big-endian */
wg_timestamp_t wgp_timestamp_latest_init;

struct timespec wgp_last_handshake_time;

callout_t wgp_handshake_timeout_timer;
callout_t wgp_session_dtor_timer;

time_t wgp_handshake_start_time;

int wgp_n_allowedips;
struct wg_allowedip wgp_allowedips[WG_ALLOWEDIPS];

time_t wgp_latest_cookie_time;
uint8_t wgp_latest_cookie[WG_COOKIE_LEN];
uint8_t wgp_last_sent_mac1[WG_MAC_LEN];
bool wgp_last_sent_mac1_valid;
uint8_t wgp_last_sent_cookie[WG_COOKIE_LEN];
bool wgp_last_sent_cookie_valid;

time_t wgp_last_msg_received_time[WG_MSG_TYPE_MAX];

time_t wgp_last_cookiesecret_time;
uint8_t wgp_cookiesecret[WG_COOKIESECRET_LEN];

struct wg_ppsratecheck wgp_ppsratecheck;

struct work wgp_work;
unsigned int wgp_tasks;
#define WGP_TASK_SEND_INIT_MESSAGE __BIT(0)
#define WGP_TASK_RETRY_HANDSHAKE __BIT(1)
#define WGP_TASK_ESTABLISH_SESSION __BIT(2)
#define WGP_TASK_ENDPOINT_CHANGED __BIT(3)
#define WGP_TASK_SEND_KEEPALIVE_MESSAGE __BIT(4)
#define WGP_TASK_DESTROY_PREV_SESSION __BIT(5)
};

struct wg_ops;

struct wg_softc {
struct ifnet wg_if;
LIST_ENTRY(wg_softc) wg_list;
kmutex_t *wg_lock;
kmutex_t *wg_intr_lock;
krwlock_t *wg_rwlock;

uint8_t wg_privkey[WG_STATIC_KEY_LEN];
uint8_t wg_pubkey[WG_STATIC_KEY_LEN];

int wg_npeers;
struct pslist_head wg_peers;
struct thmap *wg_peers_bypubkey;
struct thmap *wg_peers_byname;
struct thmap *wg_sessions_byindex;
uint16_t wg_listen_port;

struct threadpool *wg_threadpool;

struct threadpool_job wg_job;
int wg_upcalls;
#define WG_UPCALL_INET __BIT(0)
#define WG_UPCALL_INET6 __BIT(1)

#ifdef INET
struct socket *wg_so4;
struct radix_node_head *wg_rtable_ipv4;
#endif
#ifdef INET6
struct socket *wg_so6;
struct radix_node_head *wg_rtable_ipv6;
#endif

struct wg_ppsratecheck wg_ppsratecheck;

struct wg_ops *wg_ops;

#ifdef WG_RUMPKERNEL
struct wg_user *wg_user;
#endif
};

/* [W] 6.1 Preliminaries */
#define WG_REKEY_AFTER_MESSAGES (1ULL << 60)
#define WG_REJECT_AFTER_MESSAGES (UINT64_MAX - (1 << 13))
#define WG_REKEY_AFTER_TIME 120
#define WG_REJECT_AFTER_TIME 180
#define WG_REKEY_ATTEMPT_TIME 90
#define WG_REKEY_TIMEOUT 5
#define WG_KEEPALIVE_TIMEOUT 10

#define WG_COOKIE_TIME 120
#define WG_COOKIESECRET_TIME (2 * 60)

static uint64_t wg_rekey_after_messages = WG_REKEY_AFTER_MESSAGES;
static uint64_t wg_reject_after_messages = WG_REJECT_AFTER_MESSAGES;
static unsigned wg_rekey_after_time = WG_REKEY_AFTER_TIME;
static unsigned wg_reject_after_time = WG_REJECT_AFTER_TIME;
static unsigned wg_rekey_attempt_time = WG_REKEY_ATTEMPT_TIME;
static unsigned wg_rekey_timeout = WG_REKEY_TIMEOUT;
static unsigned wg_keepalive_timeout = WG_KEEPALIVE_TIMEOUT;

static struct mbuf *
wg_get_mbuf(size_t, size_t);

static void wg_send_data_msg(struct wg_peer *, struct wg_session *,
struct mbuf *);
static void wg_send_cookie_msg(struct wg_softc *, struct wg_peer *,
const uint32_t, const uint8_t[static WG_MAC_LEN],
const struct sockaddr *);
static void wg_send_handshake_msg_resp(struct wg_softc *, struct wg_peer *,
struct wg_session *, const struct wg_msg_init *);
static void wg_send_keepalive_msg(struct wg_peer *, struct wg_session *);

static struct wg_peer *
wg_pick_peer_by_sa(struct wg_softc *, const struct sockaddr *,
struct psref *);
static struct wg_peer *
wg_lookup_peer_by_pubkey(struct wg_softc *,
const uint8_t[static WG_STATIC_KEY_LEN], struct psref *);

static struct wg_session *
wg_lookup_session_by_index(struct wg_softc *,
const uint32_t, struct psref *);

static void wg_update_endpoint_if_necessary(struct wg_peer *,
const struct sockaddr *);

static void wg_schedule_session_dtor_timer(struct wg_peer *);

static bool wg_is_underload(struct wg_softc *, struct wg_peer *, int);
static void wg_calculate_keys(struct wg_session *, const bool);

static void wg_clear_states(struct wg_session *);

static void wg_get_peer(struct wg_peer *, struct psref *);
static void wg_put_peer(struct wg_peer *, struct psref *);

static int wg_send_hs(struct wg_peer *, struct mbuf *);
static int wg_send_data(struct wg_peer *, struct mbuf *);
static int wg_output(struct ifnet *, struct mbuf *,
const struct sockaddr *, const struct rtentry *);
static void wg_input(struct ifnet *, struct mbuf *, const int);
static int wg_ioctl(struct ifnet *, u_long, void *);
static int wg_bind_port(struct wg_softc *, const uint16_t);
static int wg_init(struct ifnet *);
#ifdef ALTQ
static void wg_start(struct ifnet *);
#endif
static void wg_stop(struct ifnet *, int);

static void wg_peer_work(struct work *, void *);
static void wg_job(struct threadpool_job *);
static void wgintr(void *);
static void wg_purge_pending_packets(struct wg_peer *);

static int wg_clone_create(struct if_clone *, int);
static int wg_clone_destroy(struct ifnet *);

struct wg_ops {
int (*send_hs_msg)(struct wg_peer *, struct mbuf *);
int (*send_data_msg)(struct wg_peer *, struct mbuf *);
void (*input)(struct ifnet *, struct mbuf *, const int);
int (*bind_port)(struct wg_softc *, const uint16_t);
};

struct wg_ops wg_ops_rumpkernel = {
.send_hs_msg = wg_send_hs,
.send_data_msg = wg_send_data,
.input = wg_input,
.bind_port = wg_bind_port,
};

#ifdef WG_RUMPKERNEL
static bool wg_user_mode(struct wg_softc *);
static int wg_ioctl_linkstr(struct wg_softc *, struct ifdrv *);

static int wg_send_hs_user(struct wg_peer *, struct mbuf *);
static int wg_send_data_user(struct wg_peer *, struct mbuf *);
static void wg_input_user(struct ifnet *, struct mbuf *, const int);
static int wg_bind_port_user(struct wg_softc *, const uint16_t);

struct wg_ops wg_ops_rumpuser = {
.send_hs_msg = wg_send_hs_user,
.send_data_msg = wg_send_data_user,
.input = wg_input_user,
.bind_port = wg_bind_port_user,
};
#endif

#define WG_PEER_READER_FOREACH(wgp, wg) \
PSLIST_READER_FOREACH((wgp), &(wg)->wg_peers, struct wg_peer, \
wgp_peerlist_entry)
#define WG_PEER_WRITER_FOREACH(wgp, wg) \
PSLIST_WRITER_FOREACH((wgp), &(wg)->wg_peers, struct wg_peer, \
wgp_peerlist_entry)
#define WG_PEER_WRITER_INSERT_HEAD(wgp, wg) \
PSLIST_WRITER_INSERT_HEAD(&(wg)->wg_peers, (wgp), wgp_peerlist_entry)
#define WG_PEER_WRITER_REMOVE(wgp) \
PSLIST_WRITER_REMOVE((wgp), wgp_peerlist_entry)

struct wg_route {
struct radix_node wgr_nodes[2];
struct wg_peer *wgr_peer;
};

static struct radix_node_head *
wg_rnh(struct wg_softc *wg, const int family)
{

switch (family) {
#ifdef INET
case AF_INET:
return wg->wg_rtable_ipv4;
#endif
#ifdef INET6
case AF_INET6:
return wg->wg_rtable_ipv6;
#endif
default:
return NULL;
}
}

/*
* Global variables
*/
static volatile unsigned wg_count __cacheline_aligned;

struct psref_class *wg_psref_class __read_mostly;

static struct if_clone wg_cloner =
IF_CLONE_INITIALIZER("wg", wg_clone_create, wg_clone_destroy);

static struct pktqueue *wg_pktq __read_mostly;
static struct workqueue *wg_wq __read_mostly;

void wgattach(int);
/* ARGSUSED */
void
wgattach(int count)
{
/*
* Nothing to do here, initialization is handled by the
* module initialization code in wginit() below).
*/
}

static void
wginit(void)
{

wg_psref_class = psref_class_create("wg", IPL_SOFTNET);

if_clone_attach(&wg_cloner);
}

/*
* XXX Kludge: This should just happen in wginit, but workqueue_create
* cannot be run until after CPUs have been detected, and wginit runs
* before configure.
*/
static int
wginitqueues(void)
{
int error __diagused;

wg_pktq = pktq_create(IFQ_MAXLEN, wgintr, NULL);
KASSERT(wg_pktq != NULL);

error = workqueue_create(&wg_wq, "wgpeer", wg_peer_work, NULL,
PRI_NONE, IPL_SOFTNET, WQ_MPSAFE|WQ_PERCPU);
KASSERTMSG(error == 0, "error=%d", error);

return 0;
}

static void
wg_guarantee_initialized(void)
{
static ONCE_DECL(init);
int error __diagused;

error = RUN_ONCE(&init, wginitqueues);
KASSERTMSG(error == 0, "error=%d", error);
}

static int
wg_count_inc(void)
{
unsigned o, n;

do {
o = atomic_load_relaxed(&wg_count);
if (o == UINT_MAX)
return ENFILE;
n = o + 1;
} while (atomic_cas_uint(&wg_count, o, n) != o);

return 0;
}

static void
wg_count_dec(void)
{
unsigned c __diagused;

membar_release(); /* match atomic_load_acquire in wgdetach */
c = atomic_dec_uint_nv(&wg_count);
KASSERT(c != UINT_MAX);
}

static int
wgdetach(void)
{

/* Prevent new interface creation. */
if_clone_detach(&wg_cloner);

/*
* Check whether there are any existing interfaces. Matches
* membar_release and atomic_dec_uint_nv in wg_count_dec.
*/
if (atomic_load_acquire(&wg_count)) {
/* Back out -- reattach the cloner. */
if_clone_attach(&wg_cloner);
return EBUSY;
}

/* No interfaces left. Nuke it. */
if (wg_wq)
workqueue_destroy(wg_wq);
if (wg_pktq)
pktq_destroy(wg_pktq);
psref_class_destroy(wg_psref_class);

return 0;
}

static void
wg_init_key_and_hash(uint8_t ckey[static WG_CHAINING_KEY_LEN],
uint8_t hash[static WG_HASH_LEN])
{
/* [W] 5.4: CONSTRUCTION */
const char *signature = "Noise_IKpsk2_25519_ChaChaPoly_BLAKE2s";
/* [W] 5.4: IDENTIFIER */
const char *id = "WireGuard v1 zx2c4 [email protected]";
struct blake2s state;

blake2s(ckey, WG_CHAINING_KEY_LEN, NULL, 0,
signature, strlen(signature));

CTASSERT(WG_HASH_LEN == WG_CHAINING_KEY_LEN);
memcpy(hash, ckey, WG_CHAINING_KEY_LEN);

blake2s_init(&state, WG_HASH_LEN, NULL, 0);
blake2s_update(&state, ckey, WG_CHAINING_KEY_LEN);
blake2s_update(&state, id, strlen(id));
blake2s_final(&state, hash);

WG_DUMP_HASH("ckey", ckey);
WG_DUMP_HASH("hash", hash);
}

static void
wg_algo_hash(uint8_t hash[static WG_HASH_LEN], const uint8_t input[],
const size_t inputsize)
{
struct blake2s state;

blake2s_init(&state, WG_HASH_LEN, NULL, 0);
blake2s_update(&state, hash, WG_HASH_LEN);
blake2s_update(&state, input, inputsize);
blake2s_final(&state, hash);
}

static void
wg_algo_mac(uint8_t out[], const size_t outsize,
const uint8_t key[], const size_t keylen,
const uint8_t input1[], const size_t input1len,
const uint8_t input2[], const size_t input2len)
{
struct blake2s state;

blake2s_init(&state, outsize, key, keylen);

blake2s_update(&state, input1, input1len);
if (input2 != NULL)
blake2s_update(&state, input2, input2len);
blake2s_final(&state, out);
}

static void
wg_algo_mac_mac1(uint8_t out[], const size_t outsize,
const uint8_t input1[], const size_t input1len,
const uint8_t input2[], const size_t input2len)
{
struct blake2s state;
/* [W] 5.4: LABEL-MAC1 */
const char *label = "mac1----";
uint8_t key[WG_HASH_LEN];

blake2s_init(&state, sizeof(key), NULL, 0);
blake2s_update(&state, label, strlen(label));
blake2s_update(&state, input1, input1len);
blake2s_final(&state, key);

blake2s_init(&state, outsize, key, sizeof(key));
if (input2 != NULL)
blake2s_update(&state, input2, input2len);
blake2s_final(&state, out);
}

static void
wg_algo_mac_cookie(uint8_t out[], const size_t outsize,
const uint8_t input1[], const size_t input1len)
{
struct blake2s state;
/* [W] 5.4: LABEL-COOKIE */
const char *label = "cookie--";

blake2s_init(&state, outsize, NULL, 0);
blake2s_update(&state, label, strlen(label));
blake2s_update(&state, input1, input1len);
blake2s_final(&state, out);
}

static void
wg_algo_generate_keypair(uint8_t pubkey[static WG_EPHEMERAL_KEY_LEN],
uint8_t privkey[static WG_EPHEMERAL_KEY_LEN])
{

CTASSERT(WG_EPHEMERAL_KEY_LEN == crypto_scalarmult_curve25519_BYTES);

cprng_strong(kern_cprng, privkey, WG_EPHEMERAL_KEY_LEN, 0);
crypto_scalarmult_base(pubkey, privkey);
}

static void
wg_algo_dh(uint8_t out[static WG_DH_OUTPUT_LEN],
const uint8_t privkey[static WG_STATIC_KEY_LEN],
const uint8_t pubkey[static WG_STATIC_KEY_LEN])
{

CTASSERT(WG_STATIC_KEY_LEN == crypto_scalarmult_curve25519_BYTES);

int ret __diagused = crypto_scalarmult(out, privkey, pubkey);
KASSERT(ret == 0);
}

static void
wg_algo_hmac(uint8_t out[], const size_t outlen,
const uint8_t key[], const size_t keylen,
const uint8_t in[], const size_t inlen)
{
#define IPAD 0x36
#define OPAD 0x5c
uint8_t hmackey[HMAC_BLOCK_LEN] = {0};
uint8_t ipad[HMAC_BLOCK_LEN];
uint8_t opad[HMAC_BLOCK_LEN];
size_t i;
struct blake2s state;

KASSERT(outlen == WG_HASH_LEN);
KASSERT(keylen <= HMAC_BLOCK_LEN);

memcpy(hmackey, key, keylen);

for (i = 0; i < sizeof(hmackey); i++) {
ipad[i] = hmackey[i] ^ IPAD;
opad[i] = hmackey[i] ^ OPAD;
}

blake2s_init(&state, WG_HASH_LEN, NULL, 0);
blake2s_update(&state, ipad, sizeof(ipad));
blake2s_update(&state, in, inlen);
blake2s_final(&state, out);

blake2s_init(&state, WG_HASH_LEN, NULL, 0);
blake2s_update(&state, opad, sizeof(opad));
blake2s_update(&state, out, WG_HASH_LEN);
blake2s_final(&state, out);
#undef IPAD
#undef OPAD
}

static void
wg_algo_kdf(uint8_t out1[static WG_KDF_OUTPUT_LEN],
uint8_t out2[WG_KDF_OUTPUT_LEN],
uint8_t out3[WG_KDF_OUTPUT_LEN],
const uint8_t ckey[static WG_CHAINING_KEY_LEN],
const uint8_t input[], const size_t inputlen)
{
uint8_t tmp1[WG_KDF_OUTPUT_LEN], tmp2[WG_KDF_OUTPUT_LEN + 1];
uint8_t one[1];

/*
* [N] 4.3: "an input_key_material byte sequence with length
* either zero bytes, 32 bytes, or DHLEN bytes."
*/
KASSERT(inputlen == 0 || inputlen == 32 || inputlen == NOISE_DHLEN);

WG_DUMP_HASH("ckey", ckey);
if (input != NULL)
WG_DUMP_HASH("input", input);
wg_algo_hmac(tmp1, sizeof(tmp1), ckey, WG_CHAINING_KEY_LEN,
input, inputlen);
WG_DUMP_HASH("tmp1", tmp1);
one[0] = 1;
wg_algo_hmac(out1, WG_KDF_OUTPUT_LEN, tmp1, sizeof(tmp1),
one, sizeof(one));
WG_DUMP_HASH("out1", out1);
if (out2 == NULL)
return;
memcpy(tmp2, out1, WG_KDF_OUTPUT_LEN);
tmp2[WG_KDF_OUTPUT_LEN] = 2;
wg_algo_hmac(out2, WG_KDF_OUTPUT_LEN, tmp1, sizeof(tmp1),
tmp2, sizeof(tmp2));
WG_DUMP_HASH("out2", out2);
if (out3 == NULL)
return;
memcpy(tmp2, out2, WG_KDF_OUTPUT_LEN);
tmp2[WG_KDF_OUTPUT_LEN] = 3;
wg_algo_hmac(out3, WG_KDF_OUTPUT_LEN, tmp1, sizeof(tmp1),
tmp2, sizeof(tmp2));
WG_DUMP_HASH("out3", out3);
}

static void __noinline
wg_algo_dh_kdf(uint8_t ckey[static WG_CHAINING_KEY_LEN],
uint8_t cipher_key[WG_CIPHER_KEY_LEN],
const uint8_t local_key[static WG_STATIC_KEY_LEN],
const uint8_t remote_key[static WG_STATIC_KEY_LEN])
{
uint8_t dhout[WG_DH_OUTPUT_LEN];

wg_algo_dh(dhout, local_key, remote_key);
wg_algo_kdf(ckey, cipher_key, NULL, ckey, dhout, sizeof(dhout));

WG_DUMP_HASH("dhout", dhout);
WG_DUMP_HASH("ckey", ckey);
if (cipher_key != NULL)
WG_DUMP_HASH("cipher_key", cipher_key);
}

static void
wg_algo_aead_enc(uint8_t out[], size_t expected_outsize,
const uint8_t key[static crypto_aead_chacha20poly1305_ietf_KEYBYTES],
const uint64_t counter,
const uint8_t plain[], const size_t plainsize,
const uint8_t auth[], size_t authlen)
{
uint8_t nonce[(32 + 64) / 8] = {0};
long long unsigned int outsize;
int error __diagused;

le64enc(&nonce[4], counter);

error = crypto_aead_chacha20poly1305_ietf_encrypt(out, &outsize, plain,
plainsize, auth, authlen, NULL, nonce, key);
KASSERT(error == 0);
KASSERT(outsize == expected_outsize);
}

static int
wg_algo_aead_dec(uint8_t out[], size_t expected_outsize,
const uint8_t key[static crypto_aead_chacha20poly1305_ietf_KEYBYTES],
const uint64_t counter,
const uint8_t encrypted[], const size_t encryptedsize,
const uint8_t auth[], size_t authlen)
{
uint8_t nonce[(32 + 64) / 8] = {0};
long long unsigned int outsize;
int error;

le64enc(&nonce[4], counter);

error = crypto_aead_chacha20poly1305_ietf_decrypt(out, &outsize, NULL,
encrypted, encryptedsize, auth, authlen, nonce, key);
if (error == 0)
KASSERT(outsize == expected_outsize);
return error;
}

static void
wg_algo_xaead_enc(uint8_t out[], const size_t expected_outsize,
const uint8_t key[static crypto_aead_xchacha20poly1305_ietf_KEYBYTES],
const uint8_t plain[], const size_t plainsize,
const uint8_t auth[], size_t authlen,
const uint8_t nonce[static WG_SALT_LEN])
{
long long unsigned int outsize;
int error __diagused;

CTASSERT(WG_SALT_LEN == crypto_aead_xchacha20poly1305_ietf_NPUBBYTES);
error = crypto_aead_xchacha20poly1305_ietf_encrypt(out, &outsize,
plain, plainsize, auth, authlen, NULL, nonce, key);
KASSERT(error == 0);
KASSERT(outsize == expected_outsize);
}

static int
wg_algo_xaead_dec(uint8_t out[], const size_t expected_outsize,
const uint8_t key[static crypto_aead_xchacha20poly1305_ietf_KEYBYTES],
const uint8_t encrypted[], const size_t encryptedsize,
const uint8_t auth[], size_t authlen,
const uint8_t nonce[static WG_SALT_LEN])
{
long long unsigned int outsize;
int error;

error = crypto_aead_xchacha20poly1305_ietf_decrypt(out, &outsize, NULL,
encrypted, encryptedsize, auth, authlen, nonce, key);
if (error == 0)
KASSERT(outsize == expected_outsize);
return error;
}

static void
wg_algo_tai64n(wg_timestamp_t timestamp)
{
struct timespec ts;

/* FIXME strict TAI64N (https://cr.yp.to/libtai/tai64.html) */
getnanotime(&ts);
/* TAI64 label in external TAI64 format */
be32enc(timestamp, 0x40000000U + (uint32_t)(ts.tv_sec >> 32));
/* second beginning from 1970 TAI */
be32enc(timestamp + 4, (uint32_t)(ts.tv_sec & 0xffffffffU));
/* nanosecond in big-endian format */
be32enc(timestamp + 8, (uint32_t)ts.tv_nsec);
}

/*
* wg_get_stable_session(wgp, psref)
*
* Get a passive reference to the current stable session, or
* return NULL if there is no current stable session.
*
* The pointer is always there but the session is not necessarily
* ESTABLISHED; if it is not ESTABLISHED, return NULL. However,
* the session may transition from ESTABLISHED to DESTROYING while
* holding the passive reference.
*/
static struct wg_session *
wg_get_stable_session(struct wg_peer *wgp, struct psref *psref)
{
int s;
struct wg_session *wgs;

s = pserialize_read_enter();
wgs = atomic_load_consume(&wgp->wgp_session_stable);
if (__predict_false(atomic_load_relaxed(&wgs->wgs_state) !=
WGS_STATE_ESTABLISHED))
wgs = NULL;
else
psref_acquire(psref, &wgs->wgs_psref, wg_psref_class);
pserialize_read_exit(s);

return wgs;
}

static void
wg_put_session(struct wg_session *wgs, struct psref *psref)
{

psref_release(psref, &wgs->wgs_psref, wg_psref_class);
}

static void
wg_destroy_session(struct wg_softc *wg, struct wg_session *wgs)
{
struct wg_peer *wgp = wgs->wgs_peer;
struct wg_session *wgs0 __diagused;
void *garbage;

KASSERT(mutex_owned(wgp->wgp_lock));
KASSERT(wgs->wgs_state != WGS_STATE_UNKNOWN);

/* Remove the session from the table. */
wgs0 = thmap_del(wg->wg_sessions_byindex,
&wgs->wgs_local_index, sizeof(wgs->wgs_local_index));
KASSERT(wgs0 == wgs);
garbage = thmap_stage_gc(wg->wg_sessions_byindex);

/* Wait for passive references to drain. */
pserialize_perform(wgp->wgp_psz);
psref_target_destroy(&wgs->wgs_psref, wg_psref_class);

/*
* Free memory, zero state, and transition to UNKNOWN. We have
* exclusive access to the session now, so there is no need for
* an atomic store.
*/
thmap_gc(wg->wg_sessions_byindex, garbage);
WG_DLOG("session[L=%"PRIx32" R=%"PRIx32"] -> WGS_STATE_UNKNOWN\n",
wgs->wgs_local_index, wgs->wgs_remote_index);
wgs->wgs_local_index = 0;
wgs->wgs_remote_index = 0;
wg_clear_states(wgs);
wgs->wgs_state = WGS_STATE_UNKNOWN;
wgs->wgs_force_rekey = false;
}

/*
* wg_get_session_index(wg, wgs)
*
* Choose a session index for wgs->wgs_local_index, and store it
* in wg's table of sessions by index.
*
* wgs must be the unstable session of its peer, and must be
* transitioning out of the UNKNOWN state.
*/
static void
wg_get_session_index(struct wg_softc *wg, struct wg_session *wgs)
{
struct wg_peer *wgp __diagused = wgs->wgs_peer;
struct wg_session *wgs0;
uint32_t index;

KASSERT(mutex_owned(wgp->wgp_lock));
KASSERT(wgs == wgp->wgp_session_unstable);
KASSERTMSG(wgs->wgs_state == WGS_STATE_UNKNOWN, "state=%d",
wgs->wgs_state);

do {
/* Pick a uniform random index. */
index = cprng_strong32();

/* Try to take it. */
wgs->wgs_local_index = index;
wgs0 = thmap_put(wg->wg_sessions_byindex,
&wgs->wgs_local_index, sizeof wgs->wgs_local_index, wgs);

/* If someone else beat us, start over. */
} while (__predict_false(wgs0 != wgs));
}

/*
* wg_put_session_index(wg, wgs)
*
* Remove wgs from the table of sessions by index, wait for any
* passive references to drain, and transition the session to the
* UNKNOWN state.
*
* wgs must be the unstable session of its peer, and must not be
* UNKNOWN or ESTABLISHED.
*/
static void
wg_put_session_index(struct wg_softc *wg, struct wg_session *wgs)
{
struct wg_peer *wgp __diagused = wgs->wgs_peer;

KASSERT(mutex_owned(wgp->wgp_lock));
KASSERT(wgs->wgs_state != WGS_STATE_UNKNOWN);
KASSERT(wgs->wgs_state != WGS_STATE_ESTABLISHED);

wg_destroy_session(wg, wgs);
psref_target_init(&wgs->wgs_psref, wg_psref_class);
}

/*
* Handshake patterns
*
* [W] 5: "These messages use the "IK" pattern from Noise"
* [N] 7.5. Interactive handshake patterns (fundamental)
* "The first character refers to the initiator’s static key:"
* "I = Static key for initiator Immediately transmitted to responder,
* despite reduced or absent identity hiding"
* "The second character refers to the responder’s static key:"
* "K = Static key for responder Known to initiator"
* "IK:
* <- s
* ...
* -> e, es, s, ss
* <- e, ee, se"
* [N] 9.4. Pattern modifiers
* "IKpsk2:
* <- s
* ...
* -> e, es, s, ss
* <- e, ee, se, psk"
*/
static void
wg_fill_msg_init(struct wg_softc *wg, struct wg_peer *wgp,
struct wg_session *wgs, struct wg_msg_init *wgmi)
{
uint8_t ckey[WG_CHAINING_KEY_LEN]; /* [W] 5.4.2: Ci */
uint8_t hash[WG_HASH_LEN]; /* [W] 5.4.2: Hi */
uint8_t cipher_key[WG_CIPHER_KEY_LEN];
uint8_t pubkey[WG_EPHEMERAL_KEY_LEN];
uint8_t privkey[WG_EPHEMERAL_KEY_LEN];

KASSERT(mutex_owned(wgp->wgp_lock));
KASSERT(wgs == wgp->wgp_session_unstable);
KASSERTMSG(wgs->wgs_state == WGS_STATE_INIT_ACTIVE, "state=%d",
wgs->wgs_state);

wgmi->wgmi_type = htole32(WG_MSG_TYPE_INIT);
wgmi->wgmi_sender = wgs->wgs_local_index;

/* [W] 5.4.2: First Message: Initiator to Responder */

/* Ci := HASH(CONSTRUCTION) */
/* Hi := HASH(Ci || IDENTIFIER) */
wg_init_key_and_hash(ckey, hash);
/* Hi := HASH(Hi || Sr^pub) */
wg_algo_hash(hash, wgp->wgp_pubkey, sizeof(wgp->wgp_pubkey));

WG_DUMP_HASH("hash", hash);

/* [N] 2.2: "e" */
/* Ei^priv, Ei^pub := DH-GENERATE() */
wg_algo_generate_keypair(pubkey, privkey);
/* Ci := KDF1(Ci, Ei^pub) */
wg_algo_kdf(ckey, NULL, NULL, ckey, pubkey, sizeof(pubkey));
/* msg.ephemeral := Ei^pub */
memcpy(wgmi->wgmi_ephemeral, pubkey, sizeof(wgmi->wgmi_ephemeral));
/* Hi := HASH(Hi || msg.ephemeral) */
wg_algo_hash(hash, pubkey, sizeof(pubkey));

WG_DUMP_HASH("ckey", ckey);
WG_DUMP_HASH("hash", hash);

/* [N] 2.2: "es" */
/* Ci, k := KDF2(Ci, DH(Ei^priv, Sr^pub)) */
wg_algo_dh_kdf(ckey, cipher_key, privkey, wgp->wgp_pubkey);

/* [N] 2.2: "s" */
/* msg.static := AEAD(k, 0, Si^pub, Hi) */
wg_algo_aead_enc(wgmi->wgmi_static, sizeof(wgmi->wgmi_static),
cipher_key, 0, wg->wg_pubkey, sizeof(wg->wg_pubkey),
hash, sizeof(hash));
/* Hi := HASH(Hi || msg.static) */
wg_algo_hash(hash, wgmi->wgmi_static, sizeof(wgmi->wgmi_static));

WG_DUMP_HASH48("wgmi_static", wgmi->wgmi_static);

/* [N] 2.2: "ss" */
/* Ci, k := KDF2(Ci, DH(Si^priv, Sr^pub)) */
wg_algo_dh_kdf(ckey, cipher_key, wg->wg_privkey, wgp->wgp_pubkey);

/* msg.timestamp := AEAD(k, TIMESTAMP(), Hi) */
wg_timestamp_t timestamp;
wg_algo_tai64n(timestamp);
wg_algo_aead_enc(wgmi->wgmi_timestamp, sizeof(wgmi->wgmi_timestamp),
cipher_key, 0, timestamp, sizeof(timestamp), hash, sizeof(hash));
/* Hi := HASH(Hi || msg.timestamp) */
wg_algo_hash(hash, wgmi->wgmi_timestamp, sizeof(wgmi->wgmi_timestamp));

/* [W] 5.4.4 Cookie MACs */
wg_algo_mac_mac1(wgmi->wgmi_mac1, sizeof(wgmi->wgmi_mac1),
wgp->wgp_pubkey, sizeof(wgp->wgp_pubkey),
(const uint8_t *)wgmi, offsetof(struct wg_msg_init, wgmi_mac1));
/* Need mac1 to decrypt a cookie from a cookie message */
memcpy(wgp->wgp_last_sent_mac1, wgmi->wgmi_mac1,
sizeof(wgp->wgp_last_sent_mac1));
wgp->wgp_last_sent_mac1_valid = true;

if (wgp->wgp_latest_cookie_time == 0 ||
(time_uptime - wgp->wgp_latest_cookie_time) >= WG_COOKIE_TIME)
memset(wgmi->wgmi_mac2, 0, sizeof(wgmi->wgmi_mac2));
else {
wg_algo_mac(wgmi->wgmi_mac2, sizeof(wgmi->wgmi_mac2),
wgp->wgp_latest_cookie, WG_COOKIE_LEN,
(const uint8_t *)wgmi,
offsetof(struct wg_msg_init, wgmi_mac2),
NULL, 0);
}

memcpy(wgs->wgs_ephemeral_key_pub, pubkey, sizeof(pubkey));
memcpy(wgs->wgs_ephemeral_key_priv, privkey, sizeof(privkey));
memcpy(wgs->wgs_handshake_hash, hash, sizeof(hash));
memcpy(wgs->wgs_chaining_key, ckey, sizeof(ckey));
WG_DLOG("%s: sender=%x\n", __func__, wgs->wgs_local_index);
}

/*
* wg_initiator_priority(wg, wgp)
*
* Return true if we claim priority over peer wgp as initiator at
* the moment, false if not. That is, if we and our peer are
* trying to initiate a session, do we ignore the peer's attempt
* and barge ahead with ours, or discard our attempt and accept
* the peer's?
*
* We jointly flip a coin by computing
*
* H(pubkey A) ^ H(pubkey B) ^ H(posix minutes as le64),
*
* and taking the low-order bit. If our public key hash, as a
* 256-bit integer in little-endian, is less than the peer's
* public key hash, also as a 256-bit integer in little-endian, we
* claim priority iff the bit is 0; otherwise we claim priority
* iff the bit is 1.
*
* This way, it is essentially arbitrary who claims priority, and
* it may change (by a coin toss) minute to minute, but both
* parties agree at any given moment -- except possibly at the
* boundary of a minute -- who will take priority.
*
* This is an extension to the WireGuard protocol -- as far as I
* can tell, the protocol whitepaper has no resolution to this
* deadlock scenario. According to the author, `the deadlock
* doesn't happen because of some additional state machine logic,
* and on very small chances that it does, it quickly undoes
* itself.', but this additional state machine logic does not
* appear to be anywhere in the whitepaper, and I don't see how it
* can undo itself until both sides have given up and one side is
* quicker to initiate the next time around.
*
* XXX It might be prudent to put a prefix in the hash input, so
* we avoid accidentally colliding with any other uses of the same
* hash on the same input. But it's best if any changes are
* coordinated, so that peers generally agree on what coin is
* being tossed, instead of tossing their own independent coins
* (which will also converge to working but more slowly over more
* handshake retries).
*/
static bool
wg_initiator_priority(struct wg_softc *wg, struct wg_peer *wgp)
{
const uint64_t now = time_second/60, now_le = htole64(now);
uint8_t h_min;
uint8_t h_local[BLAKE2S_MAX_DIGEST];
uint8_t h_peer[BLAKE2S_MAX_DIGEST];
int borrow;
unsigned i;

blake2s(&h_min, 1, NULL, 0, &now_le, sizeof(now_le));
blake2s(h_local, sizeof(h_local), NULL, 0,
wg->wg_pubkey, sizeof(wg->wg_pubkey));
blake2s(h_peer, sizeof(h_peer), NULL, 0,
wgp->wgp_pubkey, sizeof(wgp->wgp_pubkey));

for (borrow = 0, i = 0; i < BLAKE2S_MAX_DIGEST; i++)
borrow = (h_local[i] - h_peer[i] + borrow) >> 8;

return 1 & (h_local[0] ^ h_peer[0] ^ h_min ^ borrow);
}

static void __noinline
wg_handle_msg_init(struct wg_softc *wg, const struct wg_msg_init *wgmi,
const struct sockaddr *src)
{
uint8_t ckey[WG_CHAINING_KEY_LEN]; /* [W] 5.4.2: Ci */
uint8_t hash[WG_HASH_LEN]; /* [W] 5.4.2: Hi */
uint8_t cipher_key[WG_CIPHER_KEY_LEN];
uint8_t peer_pubkey[WG_STATIC_KEY_LEN];
struct wg_peer *wgp;
struct wg_session *wgs;
int error, ret;
struct psref psref_peer;
uint8_t mac1[WG_MAC_LEN];

WG_TRACE("init msg received");

wg_algo_mac_mac1(mac1, sizeof(mac1),
wg->wg_pubkey, sizeof(wg->wg_pubkey),
(const uint8_t *)wgmi, offsetof(struct wg_msg_init, wgmi_mac1));

/*
* [W] 5.3: Denial of Service Mitigation & Cookies
* "the responder, ..., must always reject messages with an invalid
* msg.mac1"
*/
if (!consttime_memequal(mac1, wgmi->wgmi_mac1, sizeof(mac1))) {
WG_DLOG("mac1 is invalid\n");
return;
}

/*
* [W] 5.4.2: First Message: Initiator to Responder
* "When the responder receives this message, it does the same
* operations so that its final state variables are identical,
* replacing the operands of the DH function to produce equivalent
* values."
* Note that the following comments of operations are just copies of
* the initiator's ones.
*/

/* Ci := HASH(CONSTRUCTION) */
/* Hi := HASH(Ci || IDENTIFIER) */
wg_init_key_and_hash(ckey, hash);
/* Hi := HASH(Hi || Sr^pub) */
wg_algo_hash(hash, wg->wg_pubkey, sizeof(wg->wg_pubkey));

/* [N] 2.2: "e" */
/* Ci := KDF1(Ci, Ei^pub) */
wg_algo_kdf(ckey, NULL, NULL, ckey, wgmi->wgmi_ephemeral,
sizeof(wgmi->wgmi_ephemeral));
/* Hi := HASH(Hi || msg.ephemeral) */
wg_algo_hash(hash, wgmi->wgmi_ephemeral, sizeof(wgmi->wgmi_ephemeral));

WG_DUMP_HASH("ckey", ckey);

/* [N] 2.2: "es" */
/* Ci, k := KDF2(Ci, DH(Ei^priv, Sr^pub)) */
wg_algo_dh_kdf(ckey, cipher_key, wg->wg_privkey, wgmi->wgmi_ephemeral);

WG_DUMP_HASH48("wgmi_static", wgmi->wgmi_static);

/* [N] 2.2: "s" */
/* msg.static := AEAD(k, 0, Si^pub, Hi) */
error = wg_algo_aead_dec(peer_pubkey, WG_STATIC_KEY_LEN, cipher_key, 0,
wgmi->wgmi_static, sizeof(wgmi->wgmi_static), hash, sizeof(hash));
if (error != 0) {
WG_LOG_RATECHECK(&wg->wg_ppsratecheck, LOG_DEBUG,
"%s: wg_algo_aead_dec for secret key failed\n",
if_name(&wg->wg_if));
return;
}
/* Hi := HASH(Hi || msg.static) */
wg_algo_hash(hash, wgmi->wgmi_static, sizeof(wgmi->wgmi_static));

wgp = wg_lookup_peer_by_pubkey(wg, peer_pubkey, &psref_peer);
if (wgp == NULL) {
WG_DLOG("peer not found\n");
return;
}

/*
* Lock the peer to serialize access to cookie state.
*
* XXX Can we safely avoid holding the lock across DH? Take it
* just to verify mac2 and then unlock/DH/lock?
*/
mutex_enter(wgp->wgp_lock);

if (__predict_false(wg_is_underload(wg, wgp, WG_MSG_TYPE_INIT))) {
WG_TRACE("under load");
/*
* [W] 5.3: Denial of Service Mitigation & Cookies
* "the responder, ..., and when under load may reject messages
* with an invalid msg.mac2. If the responder receives a
* message with a valid msg.mac1 yet with an invalid msg.mac2,
* and is under load, it may respond with a cookie reply
* message"
*/
uint8_t zero[WG_MAC_LEN] = {0};
if (consttime_memequal(wgmi->wgmi_mac2, zero, sizeof(zero))) {
WG_TRACE("sending a cookie message: no cookie included");
wg_send_cookie_msg(wg, wgp, wgmi->wgmi_sender,
wgmi->wgmi_mac1, src);
goto out;
}
if (!wgp->wgp_last_sent_cookie_valid) {
WG_TRACE("sending a cookie message: no cookie sent ever");
wg_send_cookie_msg(wg, wgp, wgmi->wgmi_sender,
wgmi->wgmi_mac1, src);
goto out;
}
uint8_t mac2[WG_MAC_LEN];
wg_algo_mac(mac2, sizeof(mac2), wgp->wgp_last_sent_cookie,
WG_COOKIE_LEN, (const uint8_t *)wgmi,
offsetof(struct wg_msg_init, wgmi_mac2), NULL, 0);
if (!consttime_memequal(mac2, wgmi->wgmi_mac2, sizeof(mac2))) {
WG_DLOG("mac2 is invalid\n");
goto out;
}
WG_TRACE("under load, but continue to sending");
}

/* [N] 2.2: "ss" */
/* Ci, k := KDF2(Ci, DH(Si^priv, Sr^pub)) */
wg_algo_dh_kdf(ckey, cipher_key, wg->wg_privkey, wgp->wgp_pubkey);

/* msg.timestamp := AEAD(k, TIMESTAMP(), Hi) */
wg_timestamp_t timestamp;
error = wg_algo_aead_dec(timestamp, sizeof(timestamp), cipher_key, 0,
wgmi->wgmi_timestamp, sizeof(wgmi->wgmi_timestamp),
hash, sizeof(hash));
if (error != 0) {
WG_LOG_RATECHECK(&wgp->wgp_ppsratecheck, LOG_DEBUG,
"%s: peer %s: wg_algo_aead_dec for timestamp failed\n",
if_name(&wg->wg_if), wgp->wgp_name);
goto out;
}
/* Hi := HASH(Hi || msg.timestamp) */
wg_algo_hash(hash, wgmi->wgmi_timestamp, sizeof(wgmi->wgmi_timestamp));

/*
* [W] 5.1 "The responder keeps track of the greatest timestamp
* received per peer and discards packets containing
* timestamps less than or equal to it."
*/
ret = memcmp(timestamp, wgp->wgp_timestamp_latest_init,
sizeof(timestamp));
if (ret <= 0) {
WG_LOG_RATECHECK(&wgp->wgp_ppsratecheck, LOG_DEBUG,
"%s: peer %s: invalid init msg: timestamp is old\n",
if_name(&wg->wg_if), wgp->wgp_name);
goto out;
}
memcpy(wgp->wgp_timestamp_latest_init, timestamp, sizeof(timestamp));

/*
* Message is good -- we're committing to handle it now, unless
* we were already initiating a session.
*/
wgs = wgp->wgp_session_unstable;
switch (wgs->wgs_state) {
case WGS_STATE_UNKNOWN: /* new session initiated by peer */
break;
case WGS_STATE_INIT_ACTIVE: /* we're already initiating */
if (wg_initiator_priority(wg, wgp)) {
WG_TRACE("Session already initializing,"
" ignoring the message");
goto out;
}
WG_TRACE("Yielding session initiation to peer");
wg_put_session_index(wg, wgs);
KASSERTMSG(wgs->wgs_state == WGS_STATE_UNKNOWN, "state=%d",
wgs->wgs_state);
break;
case WGS_STATE_INIT_PASSIVE: /* peer is retrying, start over */
WG_TRACE("Session already initializing, destroying old states");
/*
* XXX Avoid this -- just resend our response -- if the
* INIT message is identical to the previous one.
*/
wg_put_session_index(wg, wgs);
KASSERTMSG(wgs->wgs_state == WGS_STATE_UNKNOWN, "state=%d",
wgs->wgs_state);
break;
case WGS_STATE_ESTABLISHED: /* can't happen */
panic("unstable session can't be established");
case WGS_STATE_DESTROYING: /* rekey initiated by peer */
WG_TRACE("Session destroying, but force to clear");
wg_put_session_index(wg, wgs);
KASSERTMSG(wgs->wgs_state == WGS_STATE_UNKNOWN, "state=%d",
wgs->wgs_state);
break;
default:
panic("invalid session state: %d", wgs->wgs_state);
}

/*
* Assign a fresh session index.
*/
KASSERTMSG(wgs->wgs_state == WGS_STATE_UNKNOWN, "state=%d",
wgs->wgs_state);
wg_get_session_index(wg, wgs);

memcpy(wgs->wgs_handshake_hash, hash, sizeof(hash));
memcpy(wgs->wgs_chaining_key, ckey, sizeof(ckey));
memcpy(wgs->wgs_ephemeral_key_peer, wgmi->wgmi_ephemeral,
sizeof(wgmi->wgmi_ephemeral));

/*
* The packet is genuine. Update the peer's endpoint if the
* source address changed.
*
* XXX How to prevent DoS by replaying genuine packets from the
* wrong source address?
*/
wg_update_endpoint_if_necessary(wgp, src);

/*
* Even though we don't transition from INIT_PASSIVE to
* ESTABLISHED until we receive the first data packet from the
* initiator, we count the time of the INIT message as the time
* of establishment -- this is used to decide when to erase
* keys, and we want to start counting as soon as we have
* generated keys.
*/
wgs->wgs_time_established = time_uptime32;
wg_schedule_session_dtor_timer(wgp);

/*
* Respond to the initiator with our ephemeral public key.
*/
wg_send_handshake_msg_resp(wg, wgp, wgs, wgmi);

WG_DLOG("session[L=%"PRIx32" R=%"PRIx32"]:"
" calculate keys as responder\n",
wgs->wgs_local_index, wgs->wgs_remote_index);
wg_calculate_keys(wgs, false);
wg_clear_states(wgs);

/*
* Session is ready to receive data now that we have received
* the peer initiator's ephemeral key pair, generated our
* responder's ephemeral key pair, and derived a session key.
*
* Transition from UNKNOWN to INIT_PASSIVE to publish it to the
* data rx path, wg_handle_msg_data, where the
* atomic_load_acquire matching this atomic_store_release
* happens.
*
* (Session is not, however, ready to send data until the peer
* has acknowledged our response by sending its first data
* packet. So don't swap the sessions yet.)
*/
WG_DLOG("session[L=%"PRIx32" R=%"PRIx32"] -> WGS_STATE_INIT_PASSIVE\n",
wgs->wgs_local_index, wgs->wgs_remote_index);
atomic_store_release(&wgs->wgs_state, WGS_STATE_INIT_PASSIVE);
WG_TRACE("WGS_STATE_INIT_PASSIVE");

out:
mutex_exit(wgp->wgp_lock);
wg_put_peer(wgp, &psref_peer);
}

static struct socket *
wg_get_so_by_af(struct wg_softc *wg, const int af)
{

switch (af) {
#ifdef INET
case AF_INET:
return wg->wg_so4;
#endif
#ifdef INET6
case AF_INET6:
return wg->wg_so6;
#endif
default:
panic("wg: no such af: %d", af);
}
}

static struct socket *
wg_get_so_by_peer(struct wg_peer *wgp, struct wg_sockaddr *wgsa)
{

return wg_get_so_by_af(wgp->wgp_sc, wgsa_family(wgsa));
}

static struct wg_sockaddr *
wg_get_endpoint_sa(struct wg_peer *wgp, struct psref *psref)
{
struct wg_sockaddr *wgsa;
int s;

s = pserialize_read_enter();
wgsa = atomic_load_consume(&wgp->wgp_endpoint);
psref_acquire(psref, &wgsa->wgsa_psref, wg_psref_class);
pserialize_read_exit(s);

return wgsa;
}

static void
wg_put_sa(struct wg_peer *wgp, struct wg_sockaddr *wgsa, struct psref *psref)
{

psref_release(psref, &wgsa->wgsa_psref, wg_psref_class);
}

static int
wg_send_hs(struct wg_peer *wgp, struct mbuf *m)
{
int error;
struct socket *so;
struct psref psref;
struct wg_sockaddr *wgsa;

wgsa = wg_get_endpoint_sa(wgp, &psref);
#ifdef WG_DEBUG_LOG
char addr[128];
sockaddr_format(wgsatosa(wgsa), addr, sizeof(addr));
WG_DLOG("send handshake msg to %s\n", addr);
#endif
so = wg_get_so_by_peer(wgp, wgsa);
error = sosend(so, wgsatosa(wgsa), NULL, m, NULL, 0, curlwp);
wg_put_sa(wgp, wgsa, &psref);

return error;
}

static void
wg_send_handshake_msg_init(struct wg_softc *wg, struct wg_peer *wgp)
{
int error;
struct mbuf *m;
struct wg_msg_init *wgmi;
struct wg_session *wgs;

KASSERT(mutex_owned(wgp->wgp_lock));

wgs = wgp->wgp_session_unstable;
/* XXX pull dispatch out into wg_task_send_init_message */
switch (wgs->wgs_state) {
case WGS_STATE_UNKNOWN: /* new session initiated by us */
break;
case WGS_STATE_INIT_ACTIVE: /* we're already initiating, stop */
WG_TRACE("Session already initializing, skip starting new one");
return;
case WGS_STATE_INIT_PASSIVE: /* peer was trying -- XXX what now? */
WG_TRACE("Session already initializing, waiting for peer");
return;
case WGS_STATE_ESTABLISHED: /* can't happen */
panic("unstable session can't be established");
case WGS_STATE_DESTROYING: /* rekey initiated by us too early */
WG_TRACE("Session destroying");
wg_put_session_index(wg, wgs);
KASSERTMSG(wgs->wgs_state == WGS_STATE_UNKNOWN, "state=%d",
wgs->wgs_state);
break;
}

/*
* Assign a fresh session index.
*/
KASSERTMSG(wgs->wgs_state == WGS_STATE_UNKNOWN, "state=%d",
wgs->wgs_state);
wg_get_session_index(wg, wgs);

/*
* We have initiated a session. Transition to INIT_ACTIVE.
* This doesn't publish it for use in the data rx path,
* wg_handle_msg_data, or in the data tx path, wg_output -- we
* have to wait for the peer to respond with their ephemeral
* public key before we can derive a session key for tx/rx.
* Hence only atomic_store_relaxed.
*/
WG_DLOG("session[L=%"PRIx32" R=(unknown)] -> WGS_STATE_INIT_ACTIVE\n",
wgs->wgs_local_index);
atomic_store_relaxed(&wgs->wgs_state, WGS_STATE_INIT_ACTIVE);

m = m_gethdr(M_WAIT, MT_DATA);
if (sizeof(*wgmi) > MHLEN) {
m_clget(m, M_WAIT);
CTASSERT(sizeof(*wgmi) <= MCLBYTES);
}
m->m_pkthdr.len = m->m_len = sizeof(*wgmi);
wgmi = mtod(m, struct wg_msg_init *);
wg_fill_msg_init(wg, wgp, wgs, wgmi);

error = wg->wg_ops->send_hs_msg(wgp, m); /* consumes m */
if (error) {
/*
* Sending out an initiation packet failed; give up on
* this session and toss packet waiting for it if any.
*
* XXX Why don't we just let the periodic handshake
* retry logic work in this case?
*/
WG_DLOG("send_hs_msg failed, error=%d\n", error);
wg_put_session_index(wg, wgs);
m = atomic_swap_ptr(&wgp->wgp_pending, NULL);
membar_acquire(); /* matches membar_release in wgintr */
m_freem(m);
return;
}

WG_TRACE("init msg sent");
if (wgp->wgp_handshake_start_time == 0)
wgp->wgp_handshake_start_time = time_uptime;
callout_schedule(&wgp->wgp_handshake_timeout_timer,
MIN(wg_rekey_timeout, (unsigned)(INT_MAX / hz)) * hz);
}

static void
wg_fill_msg_resp(struct wg_softc *wg, struct wg_peer *wgp,
struct wg_session *wgs, struct wg_msg_resp *wgmr,
const struct wg_msg_init *wgmi)
{
uint8_t ckey[WG_CHAINING_KEY_LEN]; /* [W] 5.4.3: Cr */
uint8_t hash[WG_HASH_LEN]; /* [W] 5.4.3: Hr */
uint8_t cipher_key[WG_KDF_OUTPUT_LEN];
uint8_t pubkey[WG_EPHEMERAL_KEY_LEN];
uint8_t privkey[WG_EPHEMERAL_KEY_LEN];

KASSERT(mutex_owned(wgp->wgp_lock));
KASSERT(wgs == wgp->wgp_session_unstable);
KASSERTMSG(wgs->wgs_state == WGS_STATE_UNKNOWN, "state=%d",
wgs->wgs_state);

memcpy(hash, wgs->wgs_handshake_hash, sizeof(hash));
memcpy(ckey, wgs->wgs_chaining_key, sizeof(ckey));

wgmr->wgmr_type = htole32(WG_MSG_TYPE_RESP);
wgmr->wgmr_sender = wgs->wgs_local_index;
wgmr->wgmr_receiver = wgmi->wgmi_sender;

/* [W] 5.4.3 Second Message: Responder to Initiator */

/* [N] 2.2: "e" */
/* Er^priv, Er^pub := DH-GENERATE() */
wg_algo_generate_keypair(pubkey, privkey);
/* Cr := KDF1(Cr, Er^pub) */
wg_algo_kdf(ckey, NULL, NULL, ckey, pubkey, sizeof(pubkey));
/* msg.ephemeral := Er^pub */
memcpy(wgmr->wgmr_ephemeral, pubkey, sizeof(wgmr->wgmr_ephemeral));
/* Hr := HASH(Hr || msg.ephemeral) */
wg_algo_hash(hash, pubkey, sizeof(pubkey));

WG_DUMP_HASH("ckey", ckey);
WG_DUMP_HASH("hash", hash);

/* [N] 2.2: "ee" */
/* Cr := KDF1(Cr, DH(Er^priv, Ei^pub)) */
wg_algo_dh_kdf(ckey, NULL, privkey, wgs->wgs_ephemeral_key_peer);

/* [N] 2.2: "se" */
/* Cr := KDF1(Cr, DH(Er^priv, Si^pub)) */
wg_algo_dh_kdf(ckey, NULL, privkey, wgp->wgp_pubkey);

/* [N] 9.2: "psk" */
{
uint8_t kdfout[WG_KDF_OUTPUT_LEN];
/* Cr, r, k := KDF3(Cr, Q) */
wg_algo_kdf(ckey, kdfout, cipher_key, ckey, wgp->wgp_psk,
sizeof(wgp->wgp_psk));
/* Hr := HASH(Hr || r) */
wg_algo_hash(hash, kdfout, sizeof(kdfout));
}

/* msg.empty := AEAD(k, 0, e, Hr) */
wg_algo_aead_enc(wgmr->wgmr_empty, sizeof(wgmr->wgmr_empty),
cipher_key, 0, NULL, 0, hash, sizeof(hash));
/* Hr := HASH(Hr || msg.empty) */
wg_algo_hash(hash, wgmr->wgmr_empty, sizeof(wgmr->wgmr_empty));

WG_DUMP_HASH("wgmr_empty", wgmr->wgmr_empty);

/* [W] 5.4.4: Cookie MACs */
/* msg.mac1 := MAC(HASH(LABEL-MAC1 || Sm'^pub), msg_a) */
wg_algo_mac_mac1(wgmr->wgmr_mac1, sizeof(wgmi->wgmi_mac1),
wgp->wgp_pubkey, sizeof(wgp->wgp_pubkey),
(const uint8_t *)wgmr, offsetof(struct wg_msg_resp, wgmr_mac1));
/* Need mac1 to decrypt a cookie from a cookie message */
memcpy(wgp->wgp_last_sent_mac1, wgmr->wgmr_mac1,
sizeof(wgp->wgp_last_sent_mac1));
wgp->wgp_last_sent_mac1_valid = true;

if (wgp->wgp_latest_cookie_time == 0 ||
(time_uptime - wgp->wgp_latest_cookie_time) >= WG_COOKIE_TIME)
/* msg.mac2 := 0^16 */
memset(wgmr->wgmr_mac2, 0, sizeof(wgmr->wgmr_mac2));
else {
/* msg.mac2 := MAC(Lm, msg_b) */
wg_algo_mac(wgmr->wgmr_mac2, sizeof(wgmi->wgmi_mac2),
wgp->wgp_latest_cookie, WG_COOKIE_LEN,
(const uint8_t *)wgmr,
offsetof(struct wg_msg_resp, wgmr_mac2),
NULL, 0);
}

memcpy(wgs->wgs_handshake_hash, hash, sizeof(hash));
memcpy(wgs->wgs_chaining_key, ckey, sizeof(ckey));
memcpy(wgs->wgs_ephemeral_key_pub, pubkey, sizeof(pubkey));
memcpy(wgs->wgs_ephemeral_key_priv, privkey, sizeof(privkey));
wgs->wgs_remote_index = wgmi->wgmi_sender;
WG_DLOG("sender=%x\n", wgs->wgs_local_index);
WG_DLOG("receiver=%x\n", wgs->wgs_remote_index);
}

/*
* wg_swap_sessions(wg, wgp)
*
* Caller has just finished establishing the unstable session in
* wg for peer wgp. Publish it as the stable session, send queued
* packets or keepalives as necessary to kick off the session,
* move the previously stable session to unstable, and begin
* destroying it.
*/
static void
wg_swap_sessions(struct wg_softc *wg, struct wg_peer *wgp)
{
struct wg_session *wgs, *wgs_prev;
struct mbuf *m;

KASSERT(mutex_owned(wgp->wgp_lock));

/*
* Get the newly established session, to become the new
* session. Caller must have transitioned from INIT_ACTIVE to
* INIT_PASSIVE or to ESTABLISHED already. This will become
* the stable session.
*/
wgs = wgp->wgp_session_unstable;
KASSERTMSG(wgs->wgs_state == WGS_STATE_ESTABLISHED, "state=%d",
wgs->wgs_state);

/*
* Get the stable session, which is either the previously
* established session in the ESTABLISHED state, or has not
* been established at all and is UNKNOWN. This will become
* the unstable session.
*/
wgs_prev = wgp->wgp_session_stable;
KASSERTMSG((wgs_prev->wgs_state == WGS_STATE_ESTABLISHED ||
wgs_prev->wgs_state == WGS_STATE_UNKNOWN),
"state=%d", wgs_prev->wgs_state);

/*
* Publish the newly established session for the tx path to use
* and make the other one the unstable session to handle
* stragglers in the rx path and later be used for the next
* session's handshake.
*/
atomic_store_release(&wgp->wgp_session_stable, wgs);
wgp->wgp_session_unstable = wgs_prev;

/*
* Record the handshake time and reset the handshake state.
*/
getnanotime(&wgp->wgp_last_handshake_time);
wgp->wgp_handshake_start_time = 0;
wgp->wgp_last_sent_mac1_valid = false;
wgp->wgp_last_sent_cookie_valid = false;

/*
* If we had a data packet queued up, send it.
*
* If not, but we're the initiator, send a keepalive message --
* if we're the initiator we have to send something immediately
* or else the responder will never answer.
*/
if ((m = atomic_swap_ptr(&wgp->wgp_pending, NULL)) != NULL) {
membar_acquire(); /* matches membar_release in wgintr */
wg_send_data_msg(wgp, wgs, m); /* consumes m */
m = NULL;
} else if (wgs->wgs_is_initiator) {
wg_send_keepalive_msg(wgp, wgs);
}

/*
* If the previous stable session was established, begin to
* destroy it.
*/
if (wgs_prev->wgs_state == WGS_STATE_ESTABLISHED) {
/*
* Transition ESTABLISHED->DESTROYING. The session
* will remain usable for the data rx path to process
* packets still in flight to us, but we won't use it
* for data tx.
*/
WG_DLOG("session[L=%"PRIx32" R=%"PRIx32"]"
" -> WGS_STATE_DESTROYING\n",
wgs_prev->wgs_local_index, wgs_prev->wgs_remote_index);
atomic_store_relaxed(&wgs_prev->wgs_state,
WGS_STATE_DESTROYING);
} else {
KASSERTMSG(wgs_prev->wgs_state == WGS_STATE_UNKNOWN,
"state=%d", wgs_prev->wgs_state);
wgs_prev->wgs_local_index = 0; /* paranoia */
wgs_prev->wgs_remote_index = 0; /* paranoia */
wg_clear_states(wgs_prev); /* paranoia */
wgs_prev->wgs_state = WGS_STATE_UNKNOWN;
}
}

static void __noinline
wg_handle_msg_resp(struct wg_softc *wg, const struct wg_msg_resp *wgmr,
const struct sockaddr *src)
{
uint8_t ckey[WG_CHAINING_KEY_LEN]; /* [W] 5.4.3: Cr */
uint8_t hash[WG_HASH_LEN]; /* [W] 5.4.3: Kr */
uint8_t cipher_key[WG_KDF_OUTPUT_LEN];
struct wg_peer *wgp;
struct wg_session *wgs;
struct psref psref;
int error;
uint8_t mac1[WG_MAC_LEN];

wg_algo_mac_mac1(mac1, sizeof(mac1),
wg->wg_pubkey, sizeof(wg->wg_pubkey),
(const uint8_t *)wgmr, offsetof(struct wg_msg_resp, wgmr_mac1));

/*
* [W] 5.3: Denial of Service Mitigation & Cookies
* "the responder, ..., must always reject messages with an invalid
* msg.mac1"
*/
if (!consttime_memequal(mac1, wgmr->wgmr_mac1, sizeof(mac1))) {
WG_DLOG("mac1 is invalid\n");
return;
}

WG_TRACE("resp msg received");
wgs = wg_lookup_session_by_index(wg, wgmr->wgmr_receiver, &psref);
if (wgs == NULL) {
WG_TRACE("No session found");
return;
}

wgp = wgs->wgs_peer;

mutex_enter(wgp->wgp_lock);

/* If we weren't waiting for a handshake response, drop it. */
if (wgs->wgs_state != WGS_STATE_INIT_ACTIVE) {
WG_TRACE("peer sent spurious handshake response, ignoring");
goto out;
}

if (__predict_false(wg_is_underload(wg, wgp, WG_MSG_TYPE_RESP))) {
WG_TRACE("under load");
/*
* [W] 5.3: Denial of Service Mitigation & Cookies
* "the responder, ..., and when under load may reject messages
* with an invalid msg.mac2. If the responder receives a
* message with a valid msg.mac1 yet with an invalid msg.mac2,
* and is under load, it may respond with a cookie reply
* message"
*/
uint8_t zero[WG_MAC_LEN] = {0};
if (consttime_memequal(wgmr->wgmr_mac2, zero, sizeof(zero))) {
WG_TRACE("sending a cookie message: no cookie included");
wg_send_cookie_msg(wg, wgp, wgmr->wgmr_sender,
wgmr->wgmr_mac1, src);
goto out;
}
if (!wgp->wgp_last_sent_cookie_valid) {
WG_TRACE("sending a cookie message: no cookie sent ever");
wg_send_cookie_msg(wg, wgp, wgmr->wgmr_sender,
wgmr->wgmr_mac1, src);
goto out;
}
uint8_t mac2[WG_MAC_LEN];
wg_algo_mac(mac2, sizeof(mac2), wgp->wgp_last_sent_cookie,
WG_COOKIE_LEN, (const uint8_t *)wgmr,
offsetof(struct wg_msg_resp, wgmr_mac2), NULL, 0);
if (!consttime_memequal(mac2, wgmr->wgmr_mac2, sizeof(mac2))) {
WG_DLOG("mac2 is invalid\n");
goto out;
}
WG_TRACE("under load, but continue to sending");
}

memcpy(hash, wgs->wgs_handshake_hash, sizeof(hash));
memcpy(ckey, wgs->wgs_chaining_key, sizeof(ckey));

/*
* [W] 5.4.3 Second Message: Responder to Initiator
* "When the initiator receives this message, it does the same
* operations so that its final state variables are identical,
* replacing the operands of the DH function to produce equivalent
* values."
* Note that the following comments of operations are just copies of
* the initiator's ones.
*/

/* [N] 2.2: "e" */
/* Cr := KDF1(Cr, Er^pub) */
wg_algo_kdf(ckey, NULL, NULL, ckey, wgmr->wgmr_ephemeral,
sizeof(wgmr->wgmr_ephemeral));
/* Hr := HASH(Hr || msg.ephemeral) */
wg_algo_hash(hash, wgmr->wgmr_ephemeral, sizeof(wgmr->wgmr_ephemeral));

WG_DUMP_HASH("ckey", ckey);
WG_DUMP_HASH("hash", hash);

/* [N] 2.2: "ee" */
/* Cr := KDF1(Cr, DH(Er^priv, Ei^pub)) */
wg_algo_dh_kdf(ckey, NULL, wgs->wgs_ephemeral_key_priv,
wgmr->wgmr_ephemeral);

/* [N] 2.2: "se" */
/* Cr := KDF1(Cr, DH(Er^priv, Si^pub)) */
wg_algo_dh_kdf(ckey, NULL, wg->wg_privkey, wgmr->wgmr_ephemeral);

/* [N] 9.2: "psk" */
{
uint8_t kdfout[WG_KDF_OUTPUT_LEN];
/* Cr, r, k := KDF3(Cr, Q) */
wg_algo_kdf(ckey, kdfout, cipher_key, ckey, wgp->wgp_psk,
sizeof(wgp->wgp_psk));
/* Hr := HASH(Hr || r) */
wg_algo_hash(hash, kdfout, sizeof(kdfout));
}

{
uint8_t out[sizeof(wgmr->wgmr_empty)]; /* for safety */
/* msg.empty := AEAD(k, 0, e, Hr) */
error = wg_algo_aead_dec(out, 0, cipher_key, 0, wgmr->wgmr_empty,
sizeof(wgmr->wgmr_empty), hash, sizeof(hash));
WG_DUMP_HASH("wgmr_empty", wgmr->wgmr_empty);
if (error != 0) {
WG_LOG_RATECHECK(&wgp->wgp_ppsratecheck, LOG_DEBUG,
"%s: peer %s: wg_algo_aead_dec for empty message failed\n",
if_name(&wg->wg_if), wgp->wgp_name);
goto out;
}
/* Hr := HASH(Hr || msg.empty) */
wg_algo_hash(hash, wgmr->wgmr_empty, sizeof(wgmr->wgmr_empty));
}

memcpy(wgs->wgs_handshake_hash, hash, sizeof(wgs->wgs_handshake_hash));
memcpy(wgs->wgs_chaining_key, ckey, sizeof(wgs->wgs_chaining_key));
wgs->wgs_remote_index = wgmr->wgmr_sender;
WG_DLOG("receiver=%x\n", wgs->wgs_remote_index);

/*
* The packet is genuine. Update the peer's endpoint if the
* source address changed.
*
* XXX How to prevent DoS by replaying genuine packets from the
* wrong source address?
*/
wg_update_endpoint_if_necessary(wgp, src);

KASSERTMSG(wgs->wgs_state == WGS_STATE_INIT_ACTIVE, "state=%d",
wgs->wgs_state);
wgs->wgs_time_established = time_uptime32;
wg_schedule_session_dtor_timer(wgp);
wgs->wgs_time_last_data_sent = 0;
wgs->wgs_is_initiator = true;
WG_DLOG("session[L=%"PRIx32" R=%"PRIx32"]:"
" calculate keys as initiator\n",
wgs->wgs_local_index, wgs->wgs_remote_index);
wg_calculate_keys(wgs, true);
wg_clear_states(wgs);

/*
* Session is ready to receive data now that we have received
* the responder's response.
*
* Transition from INIT_ACTIVE to ESTABLISHED to publish it to
* the data rx path, wg_handle_msg_data.
*/
WG_DLOG("session[L=%"PRIx32" R=%"PRIx32" -> WGS_STATE_ESTABLISHED\n",
wgs->wgs_local_index, wgs->wgs_remote_index);
atomic_store_release(&wgs->wgs_state, WGS_STATE_ESTABLISHED);
WG_TRACE("WGS_STATE_ESTABLISHED");

callout_halt(&wgp->wgp_handshake_timeout_timer, NULL);

/*
* Session is ready to send data now that we have received the
* responder's response.
*
* Swap the sessions to publish the new one as the stable
* session for the data tx path, wg_output.
*/
wg_swap_sessions(wg, wgp);
KASSERT(wgs == wgp->wgp_session_stable);

out:
mutex_exit(wgp->wgp_lock);
wg_put_session(wgs, &psref);
}

static void
wg_send_handshake_msg_resp(struct wg_softc *wg, struct wg_peer *wgp,
struct wg_session *wgs, const struct wg_msg_init *wgmi)
{
int error;
struct mbuf *m;
struct wg_msg_resp *wgmr;

KASSERT(mutex_owned(wgp->wgp_lock));
KASSERT(wgs == wgp->wgp_session_unstable);
KASSERTMSG(wgs->wgs_state == WGS_STATE_UNKNOWN, "state=%d",
wgs->wgs_state);

m = m_gethdr(M_WAIT, MT_DATA);
if (sizeof(*wgmr) > MHLEN) {
m_clget(m, M_WAIT);
CTASSERT(sizeof(*wgmr) <= MCLBYTES);
}
m->m_pkthdr.len = m->m_len = sizeof(*wgmr);
wgmr = mtod(m, struct wg_msg_resp *);
wg_fill_msg_resp(wg, wgp, wgs, wgmr, wgmi);

error = wg->wg_ops->send_hs_msg(wgp, m); /* consumes m */
if (error) {
WG_DLOG("send_hs_msg failed, error=%d\n", error);
return;
}

WG_TRACE("resp msg sent");
}

static struct wg_peer *
wg_lookup_peer_by_pubkey(struct wg_softc *wg,
const uint8_t pubkey[static WG_STATIC_KEY_LEN], struct psref *psref)
{
struct wg_peer *wgp;

int s = pserialize_read_enter();
wgp = thmap_get(wg->wg_peers_bypubkey, pubkey, WG_STATIC_KEY_LEN);
if (wgp != NULL)
wg_get_peer(wgp, psref);
pserialize_read_exit(s);

return wgp;
}

static void
wg_fill_msg_cookie(struct wg_softc *wg, struct wg_peer *wgp,
struct wg_msg_cookie *wgmc, const uint32_t sender,
const uint8_t mac1[static WG_MAC_LEN], const struct sockaddr *src)
{
uint8_t cookie[WG_COOKIE_LEN];
uint8_t key[WG_HASH_LEN];
uint8_t addr[sizeof(struct in6_addr)];
size_t addrlen;
uint16_t uh_sport; /* be */

KASSERT(mutex_owned(wgp->wgp_lock));

wgmc->wgmc_type = htole32(WG_MSG_TYPE_COOKIE);
wgmc->wgmc_receiver = sender;
cprng_fast(wgmc->wgmc_salt, sizeof(wgmc->wgmc_salt));

/*
* [W] 5.4.7: Under Load: Cookie Reply Message
* "The secret variable, Rm, changes every two minutes to a
* random value"
*/
if ((time_uptime - wgp->wgp_last_cookiesecret_time) >
WG_COOKIESECRET_TIME) {
cprng_strong(kern_cprng, wgp->wgp_cookiesecret,
sizeof(wgp->wgp_cookiesecret), 0);
wgp->wgp_last_cookiesecret_time = time_uptime;
}

switch (src->sa_family) {
#ifdef INET
case AF_INET: {
const struct sockaddr_in *sin = satocsin(src);
addrlen = sizeof(sin->sin_addr);
memcpy(addr, &sin->sin_addr, addrlen);
uh_sport = sin->sin_port;
break;
}
#endif
#ifdef INET6
case AF_INET6: {
const struct sockaddr_in6 *sin6 = satocsin6(src);
addrlen = sizeof(sin6->sin6_addr);
memcpy(addr, &sin6->sin6_addr, addrlen);
uh_sport = sin6->sin6_port;
break;
}
#endif
default:
panic("invalid af=%d", src->sa_family);
}

wg_algo_mac(cookie, sizeof(cookie),
wgp->wgp_cookiesecret, sizeof(wgp->wgp_cookiesecret),
addr, addrlen, (const uint8_t *)&uh_sport, sizeof(uh_sport));
wg_algo_mac_cookie(key, sizeof(key), wg->wg_pubkey,
sizeof(wg->wg_pubkey));
wg_algo_xaead_enc(wgmc->wgmc_cookie, sizeof(wgmc->wgmc_cookie), key,
cookie, sizeof(cookie), mac1, WG_MAC_LEN, wgmc->wgmc_salt);

/* Need to store to calculate mac2 */
memcpy(wgp->wgp_last_sent_cookie, cookie, sizeof(cookie));
wgp->wgp_last_sent_cookie_valid = true;
}

static void
wg_send_cookie_msg(struct wg_softc *wg, struct wg_peer *wgp,
const uint32_t sender, const uint8_t mac1[static WG_MAC_LEN],
const struct sockaddr *src)
{
int error;
struct mbuf *m;
struct wg_msg_cookie *wgmc;

KASSERT(mutex_owned(wgp->wgp_lock));

m = m_gethdr(M_WAIT, MT_DATA);
if (sizeof(*wgmc) > MHLEN) {
m_clget(m, M_WAIT);
CTASSERT(sizeof(*wgmc) <= MCLBYTES);
}
m->m_pkthdr.len = m->m_len = sizeof(*wgmc);
wgmc = mtod(m, struct wg_msg_cookie *);
wg_fill_msg_cookie(wg, wgp, wgmc, sender, mac1, src);

error = wg->wg_ops->send_hs_msg(wgp, m); /* consumes m */
if (error) {
WG_DLOG("send_hs_msg failed, error=%d\n", error);
return;
}

WG_TRACE("cookie msg sent");
}

static bool
wg_is_underload(struct wg_softc *wg, struct wg_peer *wgp, int msgtype)
{
#ifdef WG_DEBUG_PARAMS
if (wg_force_underload)
return true;
#endif

/*
* XXX we don't have a means of a load estimation. The purpose of
* the mechanism is a DoS mitigation, so we consider frequent handshake
* messages as (a kind of) load; if a message of the same type comes
* to a peer within 1 second, we consider we are under load.
*/
time_t last = wgp->wgp_last_msg_received_time[msgtype];
wgp->wgp_last_msg_received_time[msgtype] = time_uptime;
return (time_uptime - last) == 0;
}

static void
wg_calculate_keys(struct wg_session *wgs, const bool initiator)
{

KASSERT(mutex_owned(wgs->wgs_peer->wgp_lock));

/*
* [W] 5.4.5: Ti^send = Tr^recv, Ti^recv = Tr^send := KDF2(Ci = Cr, e)
*/
if (initiator) {
wg_algo_kdf(wgs->wgs_tkey_send, wgs->wgs_tkey_recv, NULL,
wgs->wgs_chaining_key, NULL, 0);
} else {
wg_algo_kdf(wgs->wgs_tkey_recv, wgs->wgs_tkey_send, NULL,
wgs->wgs_chaining_key, NULL, 0);
}
WG_DUMP_HASH("wgs_tkey_send", wgs->wgs_tkey_send);
WG_DUMP_HASH("wgs_tkey_recv", wgs->wgs_tkey_recv);
}

static uint64_t
wg_session_get_send_counter(struct wg_session *wgs)
{
#ifdef __HAVE_ATOMIC64_LOADSTORE
return atomic_load_relaxed(&wgs->wgs_send_counter);
#else
uint64_t send_counter;

mutex_enter(&wgs->wgs_send_counter_lock);
send_counter = wgs->wgs_send_counter;
mutex_exit(&wgs->wgs_send_counter_lock);

return send_counter;
#endif
}

static uint64_t
wg_session_inc_send_counter(struct wg_session *wgs)
{
#ifdef __HAVE_ATOMIC64_LOADSTORE
return atomic_inc_64_nv(&wgs->wgs_send_counter) - 1;
#else
uint64_t send_counter;

mutex_enter(&wgs->wgs_send_counter_lock);
send_counter = wgs->wgs_send_counter++;
mutex_exit(&wgs->wgs_send_counter_lock);

return send_counter;
#endif
}

static void
wg_clear_states(struct wg_session *wgs)
{

KASSERT(mutex_owned(wgs->wgs_peer->wgp_lock));

wgs->wgs_send_counter = 0;
sliwin_reset(&wgs->wgs_recvwin->window);

#define wgs_clear(v) explicit_memset(wgs->wgs_##v, 0, sizeof(wgs->wgs_##v))
wgs_clear(handshake_hash);
wgs_clear(chaining_key);
wgs_clear(ephemeral_key_pub);
wgs_clear(ephemeral_key_priv);
wgs_clear(ephemeral_key_peer);
#undef wgs_clear
}

static struct wg_session *
wg_lookup_session_by_index(struct wg_softc *wg, const uint32_t index,
struct psref *psref)
{
struct wg_session *wgs;

int s = pserialize_read_enter();
wgs = thmap_get(wg->wg_sessions_byindex, &index, sizeof index);
if (wgs != NULL) {
KASSERTMSG(index == wgs->wgs_local_index,
"index=%"PRIx32" wgs->wgs_local_index=%"PRIx32,
index, wgs->wgs_local_index);
psref_acquire(psref, &wgs->wgs_psref, wg_psref_class);
}
pserialize_read_exit(s);

return wgs;
}

static void
wg_send_keepalive_msg(struct wg_peer *wgp, struct wg_session *wgs)
{
struct mbuf *m;

/*
* [W] 6.5 Passive Keepalive
* "A keepalive message is simply a transport data message with
* a zero-length encapsulated encrypted inner-packet."
*/
WG_TRACE("");
m = m_gethdr(M_WAIT, MT_DATA);
wg_send_data_msg(wgp, wgs, m);
}

static bool
wg_need_to_send_init_message(struct wg_session *wgs)
{
/*
* [W] 6.2 Transport Message Limits
* "if a peer is the initiator of a current secure session,
* WireGuard will send a handshake initiation message to begin
* a new secure session ... if after receiving a transport data
* message, the current secure session is (REJECT-AFTER-TIME −
* KEEPALIVE-TIMEOUT − REKEY-TIMEOUT) seconds old and it has
* not yet acted upon this event."
*/
return wgs->wgs_is_initiator &&
atomic_load_relaxed(&wgs->wgs_time_last_data_sent) == 0 &&
(time_uptime32 - wgs->wgs_time_established >=
(wg_reject_after_time - wg_keepalive_timeout -
wg_rekey_timeout));
}

static void
wg_schedule_peer_task(struct wg_peer *wgp, unsigned int task)
{

mutex_enter(wgp->wgp_intr_lock);
WG_DLOG("tasks=%d, task=%d\n", wgp->wgp_tasks, task);
if (wgp->wgp_tasks == 0)
/*
* XXX If the current CPU is already loaded -- e.g., if
* there's already a bunch of handshakes queued up --
* consider tossing this over to another CPU to
* distribute the load.
*/
workqueue_enqueue(wg_wq, &wgp->wgp_work, NULL);
wgp->wgp_tasks |= task;
mutex_exit(wgp->wgp_intr_lock);
}

static void
wg_change_endpoint(struct wg_peer *wgp, const struct sockaddr *new)
{
struct wg_sockaddr *wgsa_prev;

WG_TRACE("Changing endpoint");

memcpy(wgp->wgp_endpoint0, new, new->sa_len);
wgsa_prev = wgp->wgp_endpoint;
atomic_store_release(&wgp->wgp_endpoint, wgp->wgp_endpoint0);
wgp->wgp_endpoint0 = wgsa_prev;
atomic_store_release(&wgp->wgp_endpoint_available, true);

wg_schedule_peer_task(wgp, WGP_TASK_ENDPOINT_CHANGED);
}

static bool
wg_validate_inner_packet(const char *packet, size_t decrypted_len, int *af)
{
uint16_t packet_len;
const struct ip *ip;

if (__predict_false(decrypted_len < sizeof(*ip))) {
WG_DLOG("decrypted_len=%zu < %zu\n", decrypted_len,
sizeof(*ip));
return false;
}

ip = (const struct ip *)packet;
if (ip->ip_v == 4)
*af = AF_INET;
else if (ip->ip_v == 6)
*af = AF_INET6;
else {
WG_DLOG("ip_v=%d\n", ip->ip_v);
return false;
}

WG_DLOG("af=%d\n", *af);

switch (*af) {
#ifdef INET
case AF_INET:
packet_len = ntohs(ip->ip_len);
break;
#endif
#ifdef INET6
case AF_INET6: {
const struct ip6_hdr *ip6;

if (__predict_false(decrypted_len < sizeof(*ip6))) {
WG_DLOG("decrypted_len=%zu < %zu\n", decrypted_len,
sizeof(*ip6));
return false;
}

ip6 = (const struct ip6_hdr *)packet;
packet_len = sizeof(*ip6) + ntohs(ip6->ip6_plen);
break;
}
#endif
default:
return false;
}

if (packet_len > decrypted_len) {
WG_DLOG("packet_len %u > decrypted_len %zu\n", packet_len,
decrypted_len);
return false;
}

return true;
}

static bool
wg_validate_route(struct wg_softc *wg, struct wg_peer *wgp_expected,
int af, char *packet)
{
struct sockaddr_storage ss;
struct sockaddr *sa;
struct psref psref;
struct wg_peer *wgp;
bool ok;

/*
* II CRYPTOKEY ROUTING
* "it will only accept it if its source IP resolves in the
* table to the public key used in the secure session for
* decrypting it."
*/

switch (af) {
#ifdef INET
case AF_INET: {
const struct ip *ip = (const struct ip *)packet;
struct sockaddr_in *sin = (struct sockaddr_in *)&ss;
sockaddr_in_init(sin, &ip->ip_src, 0);
sa = sintosa(sin);
break;
}
#endif
#ifdef INET6
case AF_INET6: {
const struct ip6_hdr *ip6 = (const struct ip6_hdr *)packet;
struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&ss;
sockaddr_in6_init(sin6, &ip6->ip6_src, 0, 0, 0);
sa = sin6tosa(sin6);
break;
}
#endif
default:
__USE(ss);
return false;
}

wgp = wg_pick_peer_by_sa(wg, sa, &psref);
ok = (wgp == wgp_expected);
if (wgp != NULL)
wg_put_peer(wgp, &psref);

return ok;
}

static void
wg_session_dtor_timer(void *arg)
{
struct wg_peer *wgp = arg;

WG_TRACE("enter");

wg_schedule_session_dtor_timer(wgp);
wg_schedule_peer_task(wgp, WGP_TASK_DESTROY_PREV_SESSION);
}

static void
wg_schedule_session_dtor_timer(struct wg_peer *wgp)
{

/*
* If the periodic session destructor is already pending to
* handle the previous session, that's fine -- leave it in
* place; it will be scheduled again.
*/
if (callout_pending(&wgp->wgp_session_dtor_timer)) {
WG_DLOG("session dtor already pending\n");
return;
}

WG_DLOG("scheduling session dtor in %u secs\n", wg_reject_after_time);
callout_schedule(&wgp->wgp_session_dtor_timer,
wg_reject_after_time*hz);
}

static bool
sockaddr_port_match(const struct sockaddr *sa1, const struct sockaddr *sa2)
{
if (sa1->sa_family != sa2->sa_family)
return false;

switch (sa1->sa_family) {
#ifdef INET
case AF_INET:
return satocsin(sa1)->sin_port == satocsin(sa2)->sin_port;
#endif
#ifdef INET6
case AF_INET6:
return satocsin6(sa1)->sin6_port == satocsin6(sa2)->sin6_port;
#endif
default:
return false;
}
}

static void
wg_update_endpoint_if_necessary(struct wg_peer *wgp,
const struct sockaddr *src)
{
struct wg_sockaddr *wgsa;
struct psref psref;

wgsa = wg_get_endpoint_sa(wgp, &psref);

#ifdef WG_DEBUG_LOG
char oldaddr[128], newaddr[128];
sockaddr_format(wgsatosa(wgsa), oldaddr, sizeof(oldaddr));
sockaddr_format(src, newaddr, sizeof(newaddr));
WG_DLOG("old=%s, new=%s\n", oldaddr, newaddr);
#endif

/*
* III: "Since the packet has authenticated correctly, the source IP of
* the outer UDP/IP packet is used to update the endpoint for peer..."
*/
if (__predict_false(sockaddr_cmp(src, wgsatosa(wgsa)) != 0 ||
!sockaddr_port_match(src, wgsatosa(wgsa)))) {
/* XXX We can't change the endpoint twice in a short period */
if (atomic_swap_uint(&wgp->wgp_endpoint_changing, 1) == 0) {
wg_change_endpoint(wgp, src);
}
}

wg_put_sa(wgp, wgsa, &psref);
}

static void __noinline
wg_handle_msg_data(struct wg_softc *wg, struct mbuf *m,
const struct sockaddr *src)
{
struct wg_msg_data *wgmd;
char *encrypted_buf = NULL, *decrypted_buf;
size_t encrypted_len, decrypted_len;
struct wg_session *wgs;
struct wg_peer *wgp;
int state;
uint32_t age;
size_t mlen;
struct psref psref;
int error, af;
bool success, free_encrypted_buf = false, ok;
struct mbuf *n;

KASSERT(m->m_len >= sizeof(struct wg_msg_data));
wgmd = mtod(m, struct wg_msg_data *);

KASSERT(wgmd->wgmd_type == htole32(WG_MSG_TYPE_DATA));
WG_TRACE("data");

/* Find the putative session, or drop. */
wgs = wg_lookup_session_by_index(wg, wgmd->wgmd_receiver, &psref);
if (wgs == NULL) {
WG_TRACE("No session found");
m_freem(m);
return;
}

/*
* We are only ready to handle data when in INIT_PASSIVE,
* ESTABLISHED, or DESTROYING. All transitions out of that
* state dissociate the session index and drain psrefs.
*
* atomic_load_acquire matches atomic_store_release in either
* wg_handle_msg_init or wg_handle_msg_resp. (The transition
* INIT_PASSIVE to ESTABLISHED in wg_task_establish_session
* doesn't make a difference for this rx path.)
*/
state = atomic_load_acquire(&wgs->wgs_state);
switch (state) {
case WGS_STATE_UNKNOWN:
case WGS_STATE_INIT_ACTIVE:
WG_TRACE("not yet ready for data");
goto out;
case WGS_STATE_INIT_PASSIVE:
case WGS_STATE_ESTABLISHED:
case WGS_STATE_DESTROYING:
break;
}

/*
* Reject if the session is too old.
*/
age = time_uptime32 - wgs->wgs_time_established;
if (__predict_false(age >= wg_reject_after_time)) {
WG_DLOG("session %"PRIx32" too old, %"PRIu32" sec\n",
wgmd->wgmd_receiver, age);
goto out;
}

/*
* Get the peer, for rate-limited logs (XXX MPSAFE, dtrace) and
* to update the endpoint if authentication succeeds.
*/
wgp = wgs->wgs_peer;

/*
* Reject outrageously wrong sequence numbers before doing any
* crypto work or taking any locks.
*/
error = sliwin_check_fast(&wgs->wgs_recvwin->window,
le64toh(wgmd->wgmd_counter));
if (error) {
WG_LOG_RATECHECK(&wgp->wgp_ppsratecheck, LOG_DEBUG,
"%s: peer %s: out-of-window packet: %"PRIu64"\n",
if_name(&wg->wg_if), wgp->wgp_name,
le64toh(wgmd->wgmd_counter));
goto out;
}

/* Ensure the payload and authenticator are contiguous. */
mlen = m_length(m);
encrypted_len = mlen - sizeof(*wgmd);
if (encrypted_len < WG_AUTHTAG_LEN) {
WG_DLOG("Short encrypted_len: %zu\n", encrypted_len);
goto out;
}
success = m_ensure_contig(&m, sizeof(*wgmd) + encrypted_len);
if (success) {
encrypted_buf = mtod(m, char *) + sizeof(*wgmd);
} else {
encrypted_buf = kmem_intr_alloc(encrypted_len, KM_NOSLEEP);
if (encrypted_buf == NULL) {
WG_DLOG("failed to allocate encrypted_buf\n");
goto out;
}
m_copydata(m, sizeof(*wgmd), encrypted_len, encrypted_buf);
free_encrypted_buf = true;
}
/* m_ensure_contig may change m regardless of its result */
KASSERT(m->m_len >= sizeof(*wgmd));
wgmd = mtod(m, struct wg_msg_data *);

/*
* Get a buffer for the plaintext. Add WG_AUTHTAG_LEN to avoid
* a zero-length buffer (XXX). Drop if plaintext is longer
* than MCLBYTES (XXX).
*/
decrypted_len = encrypted_len - WG_AUTHTAG_LEN;
if (decrypted_len > MCLBYTES) {
/* FIXME handle larger data than MCLBYTES */
WG_DLOG("couldn't handle larger data than MCLBYTES\n");
goto out;
}
n = wg_get_mbuf(0, decrypted_len + WG_AUTHTAG_LEN);
if (n == NULL) {
WG_DLOG("wg_get_mbuf failed\n");
goto out;
}
decrypted_buf = mtod(n, char *);

/* Decrypt and verify the packet. */
WG_DLOG("mlen=%zu, encrypted_len=%zu\n", mlen, encrypted_len);
error = wg_algo_aead_dec(decrypted_buf,
encrypted_len - WG_AUTHTAG_LEN /* can be 0 */,
wgs->wgs_tkey_recv, le64toh(wgmd->wgmd_counter), encrypted_buf,
encrypted_len, NULL, 0);
if (error != 0) {
WG_LOG_RATECHECK(&wgp->wgp_ppsratecheck, LOG_DEBUG,
"%s: peer %s: failed to wg_algo_aead_dec\n",
if_name(&wg->wg_if), wgp->wgp_name);
m_freem(n);
goto out;
}
WG_DLOG("outsize=%u\n", (u_int)decrypted_len);

/* Packet is genuine. Reject it if a replay or just too old. */
mutex_enter(&wgs->wgs_recvwin->lock);
error = sliwin_update(&wgs->wgs_recvwin->window,
le64toh(wgmd->wgmd_counter));
mutex_exit(&wgs->wgs_recvwin->lock);
if (error) {
WG_LOG_RATECHECK(&wgp->wgp_ppsratecheck, LOG_DEBUG,
"%s: peer %s: replay or out-of-window packet: %"PRIu64"\n",
if_name(&wg->wg_if), wgp->wgp_name,
le64toh(wgmd->wgmd_counter));
m_freem(n);
goto out;
}

/* We're done with m now; free it and chuck the pointers. */
m_freem(m);
m = NULL;
wgmd = NULL;

/*
* The packet is genuine. Update the peer's endpoint if the
* source address changed.
*
* XXX How to prevent DoS by replaying genuine packets from the
* wrong source address?
*/
wg_update_endpoint_if_necessary(wgp, src);

/*
* Validate the encapsulated packet header and get the address
* family, or drop.
*/
ok = wg_validate_inner_packet(decrypted_buf, decrypted_len, &af);
if (!ok) {
m_freem(n);
goto update_state;
}

/* Submit it into our network stack if routable. */
ok = wg_validate_route(wg, wgp, af, decrypted_buf);
if (ok) {
wg->wg_ops->input(&wg->wg_if, n, af);
} else {
char addrstr[INET6_ADDRSTRLEN];
memset(addrstr, 0, sizeof(addrstr));
switch (af) {
#ifdef INET
case AF_INET: {
const struct ip *ip = (const struct ip *)decrypted_buf;
IN_PRINT(addrstr, &ip->ip_src);
break;
}
#endif
#ifdef INET6
case AF_INET6: {
const struct ip6_hdr *ip6 =
(const struct ip6_hdr *)decrypted_buf;
IN6_PRINT(addrstr, &ip6->ip6_src);
break;
}
#endif
default:
panic("invalid af=%d", af);
}
WG_LOG_RATECHECK(&wgp->wgp_ppsratecheck, LOG_DEBUG,
"%s: peer %s: invalid source address (%s)\n",
if_name(&wg->wg_if), wgp->wgp_name, addrstr);
m_freem(n);
/*
* The inner address is invalid however the session is valid
* so continue the session processing below.
*/
}
n = NULL;

update_state:
/* Update the state machine if necessary. */
if (__predict_false(state == WGS_STATE_INIT_PASSIVE)) {
/*
* We were waiting for the initiator to send their
* first data transport message, and that has happened.
* Schedule a task to establish this session.
*/
wg_schedule_peer_task(wgp, WGP_TASK_ESTABLISH_SESSION);
} else {
if (__predict_false(wg_need_to_send_init_message(wgs))) {
wg_schedule_peer_task(wgp, WGP_TASK_SEND_INIT_MESSAGE);
}
/*
* [W] 6.5 Passive Keepalive
* "If a peer has received a validly-authenticated transport
* data message (section 5.4.6), but does not have any packets
* itself to send back for KEEPALIVE-TIMEOUT seconds, it sends
* a keepalive message."
*/
const uint32_t now = time_uptime32;
const uint32_t time_last_data_sent =
atomic_load_relaxed(&wgs->wgs_time_last_data_sent);
WG_DLOG("time_uptime32=%"PRIu32
" wgs_time_last_data_sent=%"PRIu32"\n",
now, time_last_data_sent);
if ((now - time_last_data_sent) >= wg_keepalive_timeout) {
WG_TRACE("Schedule sending keepalive message");
/*
* We can't send a keepalive message here to avoid
* a deadlock; we already hold the solock of a socket
* that is used to send the message.
*/
wg_schedule_peer_task(wgp,
WGP_TASK_SEND_KEEPALIVE_MESSAGE);
}
}
out:
wg_put_session(wgs, &psref);
m_freem(m);
if (free_encrypted_buf)
kmem_intr_free(encrypted_buf, encrypted_len);
}

static void __noinline
wg_handle_msg_cookie(struct wg_softc *wg, const struct wg_msg_cookie *wgmc)
{
struct wg_session *wgs;
struct wg_peer *wgp;
struct psref psref;
int error;
uint8_t key[WG_HASH_LEN];
uint8_t cookie[WG_COOKIE_LEN];

WG_TRACE("cookie msg received");

/* Find the putative session. */
wgs = wg_lookup_session_by_index(wg, wgmc->wgmc_receiver, &psref);
if (wgs == NULL) {
WG_TRACE("No session found");
return;
}

/* Lock the peer so we can update the cookie state. */
wgp = wgs->wgs_peer;
mutex_enter(wgp->wgp_lock);

if (!wgp->wgp_last_sent_mac1_valid) {
WG_TRACE("No valid mac1 sent (or expired)");
goto out;
}

/*
* wgp_last_sent_mac1_valid is only set to true when we are
* transitioning to INIT_ACTIVE or INIT_PASSIVE, and always
* cleared on transition out of them.
*/
KASSERTMSG((wgs->wgs_state == WGS_STATE_INIT_ACTIVE ||
wgs->wgs_state == WGS_STATE_INIT_PASSIVE),
"state=%d", wgs->wgs_state);

/* Decrypt the cookie and store it for later handshake retry. */
wg_algo_mac_cookie(key, sizeof(key), wgp->wgp_pubkey,
sizeof(wgp->wgp_pubkey));
error = wg_algo_xaead_dec(cookie, sizeof(cookie), key,
wgmc->wgmc_cookie, sizeof(wgmc->wgmc_cookie),
wgp->wgp_last_sent_mac1, sizeof(wgp->wgp_last_sent_mac1),
wgmc->wgmc_salt);
if (error != 0) {
WG_LOG_RATECHECK(&wgp->wgp_ppsratecheck, LOG_DEBUG,
"%s: peer %s: wg_algo_aead_dec for cookie failed: "
"error=%d\n", if_name(&wg->wg_if), wgp->wgp_name, error);
goto out;
}
/*
* [W] 6.6: Interaction with Cookie Reply System
* "it should simply store the decrypted cookie value from the cookie
* reply message, and wait for the expiration of the REKEY-TIMEOUT
* timer for retrying a handshake initiation message."
*/
wgp->wgp_latest_cookie_time = time_uptime;
memcpy(wgp->wgp_latest_cookie, cookie, sizeof(wgp->wgp_latest_cookie));
out:
mutex_exit(wgp->wgp_lock);
wg_put_session(wgs, &psref);
}

static struct mbuf *
wg_validate_msg_header(struct wg_softc *wg, struct mbuf *m)
{
struct wg_msg wgm;
size_t mbuflen;
size_t msglen;

/*
* Get the mbuf chain length. It is already guaranteed, by
* wg_overudp_cb, to be large enough for a struct wg_msg.
*/
mbuflen = m_length(m);
KASSERT(mbuflen >= sizeof(struct wg_msg));

/*
* Copy the message header (32-bit message type) out -- we'll
* worry about contiguity and alignment later.
*/
m_copydata(m, 0, sizeof(wgm), &wgm);
switch (le32toh(wgm.wgm_type)) {
case WG_MSG_TYPE_INIT:
msglen = sizeof(struct wg_msg_init);
break;
case WG_MSG_TYPE_RESP:
msglen = sizeof(struct wg_msg_resp);
break;
case WG_MSG_TYPE_COOKIE:
msglen = sizeof(struct wg_msg_cookie);
break;
case WG_MSG_TYPE_DATA:
msglen = sizeof(struct wg_msg_data);
break;
default:
WG_LOG_RATECHECK(&wg->wg_ppsratecheck, LOG_DEBUG,
"%s: Unexpected msg type: %u\n", if_name(&wg->wg_if),
le32toh(wgm.wgm_type));
goto error;
}

/* Verify the mbuf chain is long enough for this type of message. */
if (__predict_false(mbuflen < msglen)) {
WG_DLOG("Invalid msg size: mbuflen=%zu type=%u\n", mbuflen,
le32toh(wgm.wgm_type));
goto error;
}

/* Make the message header contiguous if necessary. */
if (__predict_false(m->m_len < msglen)) {
m = m_pullup(m, msglen);
if (m == NULL)
return NULL;
}

return m;

error:
m_freem(m);
return NULL;
}

static void
wg_handle_packet(struct wg_softc *wg, struct mbuf *m,
const struct sockaddr *src)
{
struct wg_msg *wgm;

KASSERT(curlwp->l_pflag & LP_BOUND);

m = wg_validate_msg_header(wg, m);
if (__predict_false(m == NULL))
return;

KASSERT(m->m_len >= sizeof(struct wg_msg));
wgm = mtod(m, struct wg_msg *);
switch (le32toh(wgm->wgm_type)) {
case WG_MSG_TYPE_INIT:
wg_handle_msg_init(wg, (struct wg_msg_init *)wgm, src);
break;
case WG_MSG_TYPE_RESP:
wg_handle_msg_resp(wg, (struct wg_msg_resp *)wgm, src);
break;
case WG_MSG_TYPE_COOKIE:
wg_handle_msg_cookie(wg, (struct wg_msg_cookie *)wgm);
break;
case WG_MSG_TYPE_DATA:
wg_handle_msg_data(wg, m, src);
/* wg_handle_msg_data frees m for us */
return;
default:
panic("invalid message type: %d", le32toh(wgm->wgm_type));
}

m_freem(m);
}

static void
wg_receive_packets(struct wg_softc *wg, const int af)
{

for (;;) {
int error, flags;
struct socket *so;
struct mbuf *m = NULL;
struct uio dummy_uio;
struct mbuf *paddr = NULL;
struct sockaddr *src;

so = wg_get_so_by_af(wg, af);
flags = MSG_DONTWAIT;
dummy_uio.uio_resid = 1000000000;

error = so->so_receive(so, &paddr, &dummy_uio, &m, NULL,
&flags);
if (error || m == NULL) {
//if (error == EWOULDBLOCK)
return;
}

KASSERT(paddr != NULL);
KASSERT(paddr->m_len >= sizeof(struct sockaddr));
src = mtod(paddr, struct sockaddr *);

wg_handle_packet(wg, m, src);
}
}

static void
wg_get_peer(struct wg_peer *wgp, struct psref *psref)
{

psref_acquire(psref, &wgp->wgp_psref, wg_psref_class);
}

static void
wg_put_peer(struct wg_peer *wgp, struct psref *psref)
{

psref_release(psref, &wgp->wgp_psref, wg_psref_class);
}

static void
wg_task_send_init_message(struct wg_softc *wg, struct wg_peer *wgp)
{
struct wg_session *wgs;

WG_TRACE("WGP_TASK_SEND_INIT_MESSAGE");

KASSERT(mutex_owned(wgp->wgp_lock));

if (!atomic_load_acquire(&wgp->wgp_endpoint_available)) {
WGLOG(LOG_DEBUG, "%s: No endpoint available\n",
if_name(&wg->wg_if));
/* XXX should do something? */
return;
}

/*
* If we already have an established session, there's no need
* to initiate a new one -- unless the rekey-after-time or
* rekey-after-messages limits have passed.
*/
wgs = wgp->wgp_session_stable;
if (wgs->wgs_state == WGS_STATE_ESTABLISHED &&
!atomic_load_relaxed(&wgs->wgs_force_rekey))
return;

/*
* Ensure we're initiating a new session. If the unstable
* session is already INIT_ACTIVE or INIT_PASSIVE, this does
* nothing.
*/
wg_send_handshake_msg_init(wg, wgp);
}

static void
wg_task_retry_handshake(struct wg_softc *wg, struct wg_peer *wgp)
{
struct wg_session *wgs;

WG_TRACE("WGP_TASK_RETRY_HANDSHAKE");

KASSERT(mutex_owned(wgp->wgp_lock));

wgs = wgp->wgp_session_unstable;
if (wgs->wgs_state != WGS_STATE_INIT_ACTIVE)
return;

KASSERT(wgp->wgp_handshake_start_time != 0);

/*
* XXX no real need to assign a new index here, but we do need
* to transition to UNKNOWN temporarily
*/
wg_put_session_index(wg, wgs);

/* [W] 6.4 Handshake Initiation Retransmission */
if ((time_uptime - wgp->wgp_handshake_start_time) >
wg_rekey_attempt_time) {
/* Give up handshaking */
wgp->wgp_handshake_start_time = 0;
WG_TRACE("give up");

/*
* If a new data packet comes, handshaking will be retried
* and a new session would be established at that time,
* however we don't want to send pending packets then.
*/
wg_purge_pending_packets(wgp);
return;
}

wg_task_send_init_message(wg, wgp);
}

static void
wg_task_establish_session(struct wg_softc *wg, struct wg_peer *wgp)
{
struct wg_session *wgs;

KASSERT(mutex_owned(wgp->wgp_lock));

wgs = wgp->wgp_session_unstable;
if (wgs->wgs_state != WGS_STATE_INIT_PASSIVE)
/* XXX Can this happen? */
return;

wgs->wgs_time_last_data_sent = 0;
wgs->wgs_is_initiator = false;

/*
* Session was already ready to receive data. Transition from
* INIT_PASSIVE to ESTABLISHED just so we can swap the
* sessions.
*
* atomic_store_relaxed because this doesn't affect the data rx
* path, wg_handle_msg_data -- changing from INIT_PASSIVE to
* ESTABLISHED makes no difference to the data rx path, and the
* transition to INIT_PASSIVE with store-release already
* published the state needed by the data rx path.
*/
WG_DLOG("session[L=%"PRIx32" R=%"PRIx32"] -> WGS_STATE_ESTABLISHED\n",
wgs->wgs_local_index, wgs->wgs_remote_index);
atomic_store_relaxed(&wgs->wgs_state, WGS_STATE_ESTABLISHED);
WG_TRACE("WGS_STATE_ESTABLISHED");

/*
* Session is ready to send data too now that we have received
* the peer initiator's first data packet.
*
* Swap the sessions to publish the new one as the stable
* session for the data tx path, wg_output.
*/
wg_swap_sessions(wg, wgp);
KASSERT(wgs == wgp->wgp_session_stable);
}

static void
wg_task_endpoint_changed(struct wg_softc *wg, struct wg_peer *wgp)
{

WG_TRACE("WGP_TASK_ENDPOINT_CHANGED");

KASSERT(mutex_owned(wgp->wgp_lock));

if (atomic_load_relaxed(&wgp->wgp_endpoint_changing)) {
pserialize_perform(wgp->wgp_psz);
mutex_exit(wgp->wgp_lock);
psref_target_destroy(&wgp->wgp_endpoint0->wgsa_psref,
wg_psref_class);
psref_target_init(&wgp->wgp_endpoint0->wgsa_psref,
wg_psref_class);
mutex_enter(wgp->wgp_lock);
atomic_store_release(&wgp->wgp_endpoint_changing, 0);
}
}

static void
wg_task_send_keepalive_message(struct wg_softc *wg, struct wg_peer *wgp)
{
struct wg_session *wgs;

WG_TRACE("WGP_TASK_SEND_KEEPALIVE_MESSAGE");

KASSERT(mutex_owned(wgp->wgp_lock));

wgs = wgp->wgp_session_stable;
if (wgs->wgs_state != WGS_STATE_ESTABLISHED)
return;

wg_send_keepalive_msg(wgp, wgs);
}

static void
wg_task_destroy_prev_session(struct wg_softc *wg, struct wg_peer *wgp)
{
struct wg_session *wgs;
uint32_t age;

WG_TRACE("WGP_TASK_DESTROY_PREV_SESSION");

KASSERT(mutex_owned(wgp->wgp_lock));

/*
* If theres's any previous unstable session, i.e., one that
* was ESTABLISHED and is now DESTROYING, older than
* reject-after-time, destroy it. Upcoming sessions are still
* in INIT_ACTIVE or INIT_PASSIVE -- we don't touch those here.
*/
wgs = wgp->wgp_session_unstable;
KASSERT(wgs->wgs_state != WGS_STATE_ESTABLISHED);
if (wgs->wgs_state == WGS_STATE_DESTROYING &&
((age = (time_uptime32 - wgs->wgs_time_established)) >=
wg_reject_after_time)) {
WG_DLOG("destroying past session %"PRIu32" sec old\n", age);
wg_put_session_index(wg, wgs);
KASSERTMSG(wgs->wgs_state == WGS_STATE_UNKNOWN, "state=%d",
wgs->wgs_state);
}

/*
* If theres's any ESTABLISHED stable session older than
* reject-after-time, destroy it. (The stable session can also
* be in UNKNOWN state -- nothing to do in that case)
*/
wgs = wgp->wgp_session_stable;
KASSERT(wgs->wgs_state != WGS_STATE_INIT_ACTIVE);
KASSERT(wgs->wgs_state != WGS_STATE_INIT_PASSIVE);
KASSERT(wgs->wgs_state != WGS_STATE_DESTROYING);
if (wgs->wgs_state == WGS_STATE_ESTABLISHED &&
((age = (time_uptime32 - wgs->wgs_time_established)) >=
wg_reject_after_time)) {
WG_DLOG("destroying current session %"PRIu32" sec old\n", age);
atomic_store_relaxed(&wgs->wgs_state, WGS_STATE_DESTROYING);
wg_put_session_index(wg, wgs);
KASSERTMSG(wgs->wgs_state == WGS_STATE_UNKNOWN, "state=%d",
wgs->wgs_state);
}

/*
* If there's no sessions left, no need to have the timer run
* until the next time around -- halt it.
*
* It is only ever scheduled with wgp_lock held or in the
* callout itself, and callout_halt prevents rescheudling
* itself, so this never races with rescheduling.
*/
if (wgp->wgp_session_unstable->wgs_state == WGS_STATE_UNKNOWN &&
wgp->wgp_session_stable->wgs_state == WGS_STATE_UNKNOWN)
callout_halt(&wgp->wgp_session_dtor_timer, NULL);
}

static void
wg_peer_work(struct work *wk, void *cookie)
{
struct wg_peer *wgp = container_of(wk, struct wg_peer, wgp_work);
struct wg_softc *wg = wgp->wgp_sc;
unsigned int tasks;

mutex_enter(wgp->wgp_intr_lock);
while ((tasks = wgp->wgp_tasks) != 0) {
wgp->wgp_tasks = 0;
mutex_exit(wgp->wgp_intr_lock);

mutex_enter(wgp->wgp_lock);
if (ISSET(tasks, WGP_TASK_SEND_INIT_MESSAGE))
wg_task_send_init_message(wg, wgp);
if (ISSET(tasks, WGP_TASK_RETRY_HANDSHAKE))
wg_task_retry_handshake(wg, wgp);
if (ISSET(tasks, WGP_TASK_ESTABLISH_SESSION))
wg_task_establish_session(wg, wgp);
if (ISSET(tasks, WGP_TASK_ENDPOINT_CHANGED))
wg_task_endpoint_changed(wg, wgp);
if (ISSET(tasks, WGP_TASK_SEND_KEEPALIVE_MESSAGE))
wg_task_send_keepalive_message(wg, wgp);
if (ISSET(tasks, WGP_TASK_DESTROY_PREV_SESSION))
wg_task_destroy_prev_session(wg, wgp);
mutex_exit(wgp->wgp_lock);

mutex_enter(wgp->wgp_intr_lock);
}
mutex_exit(wgp->wgp_intr_lock);
}

static void
wg_job(struct threadpool_job *job)
{
struct wg_softc *wg = container_of(job, struct wg_softc, wg_job);
int bound, upcalls;

mutex_enter(wg->wg_intr_lock);
while ((upcalls = wg->wg_upcalls) != 0) {
wg->wg_upcalls = 0;
mutex_exit(wg->wg_intr_lock);
bound = curlwp_bind();
if (ISSET(upcalls, WG_UPCALL_INET))
wg_receive_packets(wg, AF_INET);
if (ISSET(upcalls, WG_UPCALL_INET6))
wg_receive_packets(wg, AF_INET6);
curlwp_bindx(bound);
mutex_enter(wg->wg_intr_lock);
}
threadpool_job_done(job);
mutex_exit(wg->wg_intr_lock);
}

static int
wg_bind_port(struct wg_softc *wg, const uint16_t port)
{
int error = 0;
uint16_t old_port = wg->wg_listen_port;

if (port != 0 && old_port == port)
return 0;

#ifdef INET
struct sockaddr_in _sin, *sin = &_sin;
sin->sin_len = sizeof(*sin);
sin->sin_family = AF_INET;
sin->sin_addr.s_addr = INADDR_ANY;
sin->sin_port = htons(port);

error = sobind(wg->wg_so4, sintosa(sin), curlwp);
if (error)
return error;
#endif

#ifdef INET6
struct sockaddr_in6 _sin6, *sin6 = &_sin6;
sin6->sin6_len = sizeof(*sin6);
sin6->sin6_family = AF_INET6;
sin6->sin6_addr = in6addr_any;
sin6->sin6_port = htons(port);

error = sobind(wg->wg_so6, sin6tosa(sin6), curlwp);
if (error)
return error;
#endif

wg->wg_listen_port = port;

return error;
}

static void
wg_so_upcall(struct socket *so, void *cookie, int events, int waitflag)
{
struct wg_softc *wg = cookie;
int reason;

reason = (so->so_proto->pr_domain->dom_family == AF_INET) ?
WG_UPCALL_INET :
WG_UPCALL_INET6;

mutex_enter(wg->wg_intr_lock);
wg->wg_upcalls |= reason;
threadpool_schedule_job(wg->wg_threadpool, &wg->wg_job);
mutex_exit(wg->wg_intr_lock);
}

/*
* wg_overudp_cb(&m, offset, so, src, arg)
*
* Callback for incoming UDP packets in high-priority
* packet-processing path.
*
* Three cases:
*
* - Data packet. Consumed here for high-priority handling.
* => Returns 1 and takes ownership of m.
*
* - Handshake packet. Defer to thread context via so_receive in
* wg_receive_packets.
* => Returns 0 and leaves caller with ownership of m.
*
* - Invalid. Dropped on the floor and freed.
* => Returns -1 and takes ownership of m (frees m).
*/
static int
wg_overudp_cb(struct mbuf **mp, int offset, struct socket *so,
struct sockaddr *src, void *arg)
{
struct wg_softc *wg = arg;
struct wg_msg wgm;
struct mbuf *m = *mp;

WG_TRACE("enter");

/* Verify the mbuf chain is long enough to have a wg msg header. */
KASSERT(offset <= m_length(m));
if (__predict_false(m_length(m) - offset < sizeof(struct wg_msg))) {
/* drop on the floor */
m_freem(m);
*mp = NULL;
return -1; /* dropped */
}

/*
* Copy the message header (32-bit message type) out -- we'll
* worry about contiguity and alignment later.
*/
m_copydata(m, offset, sizeof(struct wg_msg), &wgm);
WG_DLOG("type=%d\n", le32toh(wgm.wgm_type));

/*
* Handle DATA packets promptly as they arrive, if they are in
* an active session. Other packets may require expensive
* public-key crypto and are not as sensitive to latency, so
* defer them to the worker thread.
*/
switch (le32toh(wgm.wgm_type)) {
case WG_MSG_TYPE_DATA:
/* handle immediately */
m_adj(m, offset);
if (__predict_false(m->m_len < sizeof(struct wg_msg_data))) {
m = m_pullup(m, sizeof(struct wg_msg_data));
if (m == NULL) {
*mp = NULL;
return -1; /* dropped */
}
}
wg_handle_msg_data(wg, m, src);
*mp = NULL;
return 1; /* consumed */
case WG_MSG_TYPE_INIT:
case WG_MSG_TYPE_RESP:
case WG_MSG_TYPE_COOKIE:
/* pass through to so_receive in wg_receive_packets */
return 0; /* passthrough */
default:
/* drop on the floor */
m_freem(m);
*mp = NULL;
return -1; /* dropped */
}
}

static int
wg_socreate(struct wg_softc *wg, int af, struct socket **sop)
{
int error;
struct socket *so;

error = socreate(af, &so, SOCK_DGRAM, 0, curlwp, NULL);
if (error != 0)
return error;

solock(so);
so->so_upcallarg = wg;
so->so_upcall = wg_so_upcall;
so->so_rcv.sb_flags |= SB_UPCALL;
inpcb_register_overudp_cb(sotoinpcb(so), wg_overudp_cb, wg);
sounlock(so);

*sop = so;

return 0;
}

static bool
wg_session_hit_limits(struct wg_session *wgs)
{

/*
* [W] 6.2: Transport Message Limits
* "After REJECT-AFTER-MESSAGES transport data messages or after the
* current secure session is REJECT-AFTER-TIME seconds old, whichever
* comes first, WireGuard will refuse to send or receive any more
* transport data messages using the current secure session, ..."
*/
KASSERT(wgs->wgs_time_established != 0 || time_uptime > UINT32_MAX);
if (time_uptime32 - wgs->wgs_time_established > wg_reject_after_time) {
WG_DLOG("The session hits REJECT_AFTER_TIME\n");
return true;
} else if (wg_session_get_send_counter(wgs) >
wg_reject_after_messages) {
WG_DLOG("The session hits REJECT_AFTER_MESSAGES\n");
return true;
}

return false;
}

static void
wgintr(void *cookie)
{
struct wg_peer *wgp;
struct wg_session *wgs;
struct mbuf *m;
struct psref psref;

while ((m = pktq_dequeue(wg_pktq)) != NULL) {
wgp = M_GETCTX(m, struct wg_peer *);
if ((wgs = wg_get_stable_session(wgp, &psref)) == NULL) {
/*
* No established session. If we're the first
* to try sending data, schedule a handshake
* and queue the packet for when the handshake
* is done; otherwise just drop the packet and
* let the ongoing handshake attempt continue.
* We could queue more data packets but it's
* not clear that's worthwhile.
*/
WG_TRACE("no stable session");
membar_release();
if ((m = atomic_swap_ptr(&wgp->wgp_pending, m)) ==
NULL) {
WG_TRACE("queued first packet;"
" init handshake");
wg_schedule_peer_task(wgp,
WGP_TASK_SEND_INIT_MESSAGE);
} else {
membar_acquire();
WG_TRACE("first packet already queued,"
" dropping");
}
goto next0;
}
if (__predict_false(wg_session_hit_limits(wgs))) {
WG_TRACE("stable session hit limits");
membar_release();
if ((m = atomic_swap_ptr(&wgp->wgp_pending, m)) ==
NULL) {
WG_TRACE("queued first packet in a while;"
" reinit handshake");
atomic_store_relaxed(&wgs->wgs_force_rekey,
true);
wg_schedule_peer_task(wgp,
WGP_TASK_SEND_INIT_MESSAGE);
} else {
membar_acquire();
WG_TRACE("first packet in already queued,"
" dropping");
}
goto next1;
}
wg_send_data_msg(wgp, wgs, m);
m = NULL; /* consumed */
next1: wg_put_session(wgs, &psref);
next0: m_freem(m);
/* XXX Yield to avoid userland starvation? */
}
}

static void
wg_purge_pending_packets(struct wg_peer *wgp)
{
struct mbuf *m;

m = atomic_swap_ptr(&wgp->wgp_pending, NULL);
membar_acquire(); /* matches membar_release in wgintr */
m_freem(m);
#ifdef ALTQ
wg_start(&wgp->wgp_sc->wg_if);
#endif
pktq_barrier(wg_pktq);
}

static void
wg_handshake_timeout_timer(void *arg)
{
struct wg_peer *wgp = arg;

WG_TRACE("enter");

wg_schedule_peer_task(wgp, WGP_TASK_RETRY_HANDSHAKE);
}

static struct wg_peer *
wg_alloc_peer(struct wg_softc *wg)
{
struct wg_peer *wgp;

wgp = kmem_zalloc(sizeof(*wgp), KM_SLEEP);

wgp->wgp_sc = wg;
callout_init(&wgp->wgp_handshake_timeout_timer, CALLOUT_MPSAFE);
callout_setfunc(&wgp->wgp_handshake_timeout_timer,
wg_handshake_timeout_timer, wgp);
callout_init(&wgp->wgp_session_dtor_timer, CALLOUT_MPSAFE);
callout_setfunc(&wgp->wgp_session_dtor_timer,
wg_session_dtor_timer, wgp);
PSLIST_ENTRY_INIT(wgp, wgp_peerlist_entry);
wgp->wgp_endpoint_changing = false;
wgp->wgp_endpoint_available = false;
wgp->wgp_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
wgp->wgp_intr_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_SOFTNET);
wgp->wgp_psz = pserialize_create();
psref_target_init(&wgp->wgp_psref, wg_psref_class);

wgp->wgp_endpoint = kmem_zalloc(sizeof(*wgp->wgp_endpoint), KM_SLEEP);
wgp->wgp_endpoint0 = kmem_zalloc(sizeof(*wgp->wgp_endpoint0), KM_SLEEP);
psref_target_init(&wgp->wgp_endpoint->wgsa_psref, wg_psref_class);
psref_target_init(&wgp->wgp_endpoint0->wgsa_psref, wg_psref_class);

struct wg_session *wgs;
wgp->wgp_session_stable =
kmem_zalloc(sizeof(*wgp->wgp_session_stable), KM_SLEEP);
wgp->wgp_session_unstable =
kmem_zalloc(sizeof(*wgp->wgp_session_unstable), KM_SLEEP);
wgs = wgp->wgp_session_stable;
wgs->wgs_peer = wgp;
wgs->wgs_state = WGS_STATE_UNKNOWN;
psref_target_init(&wgs->wgs_psref, wg_psref_class);
#ifndef __HAVE_ATOMIC64_LOADSTORE
mutex_init(&wgs->wgs_send_counter_lock, MUTEX_DEFAULT, IPL_SOFTNET);
#endif
wgs->wgs_recvwin = kmem_zalloc(sizeof(*wgs->wgs_recvwin), KM_SLEEP);
mutex_init(&wgs->wgs_recvwin->lock, MUTEX_DEFAULT, IPL_SOFTNET);

wgs = wgp->wgp_session_unstable;
wgs->wgs_peer = wgp;
wgs->wgs_state = WGS_STATE_UNKNOWN;
psref_target_init(&wgs->wgs_psref, wg_psref_class);
#ifndef __HAVE_ATOMIC64_LOADSTORE
mutex_init(&wgs->wgs_send_counter_lock, MUTEX_DEFAULT, IPL_SOFTNET);
#endif
wgs->wgs_recvwin = kmem_zalloc(sizeof(*wgs->wgs_recvwin), KM_SLEEP);
mutex_init(&wgs->wgs_recvwin->lock, MUTEX_DEFAULT, IPL_SOFTNET);

return wgp;
}

static void
wg_destroy_peer(struct wg_peer *wgp)
{
struct wg_session *wgs;
struct wg_softc *wg = wgp->wgp_sc;

/* Prevent new packets from this peer on any source address. */
rw_enter(wg->wg_rwlock, RW_WRITER);
for (int i = 0; i < wgp->wgp_n_allowedips; i++) {
struct wg_allowedip *wga = &wgp->wgp_allowedips[i];
struct radix_node_head *rnh = wg_rnh(wg, wga->wga_family);
struct radix_node *rn;

KASSERT(rnh != NULL);
rn = rnh->rnh_deladdr(&wga->wga_sa_addr,
&wga->wga_sa_mask, rnh);
if (rn == NULL) {
char addrstr[128];
sockaddr_format(&wga->wga_sa_addr, addrstr,
sizeof(addrstr));
WGLOG(LOG_WARNING, "%s: Couldn't delete %s",
if_name(&wg->wg_if), addrstr);
}
}
rw_exit(wg->wg_rwlock);

/* Purge pending packets. */
wg_purge_pending_packets(wgp);

/* Halt all packet processing and timeouts. */
callout_halt(&wgp->wgp_handshake_timeout_timer, NULL);
callout_halt(&wgp->wgp_session_dtor_timer, NULL);

/* Wait for any queued work to complete. */
workqueue_wait(wg_wq, &wgp->wgp_work);

wgs = wgp->wgp_session_unstable;
if (wgs->wgs_state != WGS_STATE_UNKNOWN) {
mutex_enter(wgp->wgp_lock);
wg_destroy_session(wg, wgs);
mutex_exit(wgp->wgp_lock);
}
mutex_destroy(&wgs->wgs_recvwin->lock);
kmem_free(wgs->wgs_recvwin, sizeof(*wgs->wgs_recvwin));
#ifndef __HAVE_ATOMIC64_LOADSTORE
mutex_destroy(&wgs->wgs_send_counter_lock);
#endif
kmem_free(wgs, sizeof(*wgs));

wgs = wgp->wgp_session_stable;
if (wgs->wgs_state != WGS_STATE_UNKNOWN) {
mutex_enter(wgp->wgp_lock);
wg_destroy_session(wg, wgs);
mutex_exit(wgp->wgp_lock);
}
mutex_destroy(&wgs->wgs_recvwin->lock);
kmem_free(wgs->wgs_recvwin, sizeof(*wgs->wgs_recvwin));
#ifndef __HAVE_ATOMIC64_LOADSTORE
mutex_destroy(&wgs->wgs_send_counter_lock);
#endif
kmem_free(wgs, sizeof(*wgs));

psref_target_destroy(&wgp->wgp_endpoint->wgsa_psref, wg_psref_class);
psref_target_destroy(&wgp->wgp_endpoint0->wgsa_psref, wg_psref_class);
kmem_free(wgp->wgp_endpoint, sizeof(*wgp->wgp_endpoint));
kmem_free(wgp->wgp_endpoint0, sizeof(*wgp->wgp_endpoint0));

pserialize_destroy(wgp->wgp_psz);
mutex_obj_free(wgp->wgp_intr_lock);
mutex_obj_free(wgp->wgp_lock);

kmem_free(wgp, sizeof(*wgp));
}

static void
wg_destroy_all_peers(struct wg_softc *wg)
{
struct wg_peer *wgp, *wgp0 __diagused;
void *garbage_byname, *garbage_bypubkey;

restart:
garbage_byname = garbage_bypubkey = NULL;
mutex_enter(wg->wg_lock);
WG_PEER_WRITER_FOREACH(wgp, wg) {
if (wgp->wgp_name[0]) {
wgp0 = thmap_del(wg->wg_peers_byname, wgp->wgp_name,
strlen(wgp->wgp_name));
KASSERT(wgp0 == wgp);
garbage_byname = thmap_stage_gc(wg->wg_peers_byname);
}
wgp0 = thmap_del(wg->wg_peers_bypubkey, wgp->wgp_pubkey,
sizeof(wgp->wgp_pubkey));
KASSERT(wgp0 == wgp);
garbage_bypubkey = thmap_stage_gc(wg->wg_peers_bypubkey);
WG_PEER_WRITER_REMOVE(wgp);
wg->wg_npeers--;
mutex_enter(wgp->wgp_lock);
pserialize_perform(wgp->wgp_psz);
mutex_exit(wgp->wgp_lock);
PSLIST_ENTRY_DESTROY(wgp, wgp_peerlist_entry);
break;
}
mutex_exit(wg->wg_lock);

if (wgp == NULL)
return;

psref_target_destroy(&wgp->wgp_psref, wg_psref_class);

wg_destroy_peer(wgp);
thmap_gc(wg->wg_peers_byname, garbage_byname);
thmap_gc(wg->wg_peers_bypubkey, garbage_bypubkey);

goto restart;
}

static int
wg_destroy_peer_name(struct wg_softc *wg, const char *name)
{
struct wg_peer *wgp, *wgp0 __diagused;
void *garbage_byname, *garbage_bypubkey;

mutex_enter(wg->wg_lock);
wgp = thmap_del(wg->wg_peers_byname, name, strlen(name));
if (wgp != NULL) {
wgp0 = thmap_del(wg->wg_peers_bypubkey, wgp->wgp_pubkey,
sizeof(wgp->wgp_pubkey));
KASSERT(wgp0 == wgp);
garbage_byname = thmap_stage_gc(wg->wg_peers_byname);
garbage_bypubkey = thmap_stage_gc(wg->wg_peers_bypubkey);
WG_PEER_WRITER_REMOVE(wgp);
wg->wg_npeers--;
if (wg->wg_npeers == 0)
if_link_state_change(&wg->wg_if, LINK_STATE_DOWN);
mutex_enter(wgp->wgp_lock);
pserialize_perform(wgp->wgp_psz);
mutex_exit(wgp->wgp_lock);
PSLIST_ENTRY_DESTROY(wgp, wgp_peerlist_entry);
}
mutex_exit(wg->wg_lock);

if (wgp == NULL)
return ENOENT;

psref_target_destroy(&wgp->wgp_psref, wg_psref_class);

wg_destroy_peer(wgp);
thmap_gc(wg->wg_peers_byname, garbage_byname);
thmap_gc(wg->wg_peers_bypubkey, garbage_bypubkey);

return 0;
}

static int
wg_if_attach(struct wg_softc *wg)
{

wg->wg_if.if_addrlen = 0;
wg->wg_if.if_mtu = WG_MTU;
wg->wg_if.if_flags = IFF_MULTICAST;
wg->wg_if.if_extflags = IFEF_MPSAFE;
wg->wg_if.if_ioctl = wg_ioctl;
wg->wg_if.if_output = wg_output;
wg->wg_if.if_init = wg_init;
#ifdef ALTQ
wg->wg_if.if_start = wg_start;
#endif
wg->wg_if.if_stop = wg_stop;
wg->wg_if.if_type = IFT_OTHER;
wg->wg_if.if_dlt = DLT_NULL;
wg->wg_if.if_softc = wg;
#ifdef ALTQ
IFQ_SET_READY(&wg->wg_if.if_snd);
#endif
if_initialize(&wg->wg_if);

wg->wg_if.if_link_state = LINK_STATE_DOWN;
if_alloc_sadl(&wg->wg_if);
if_register(&wg->wg_if);

bpf_attach(&wg->wg_if, DLT_NULL, sizeof(uint32_t));

return 0;
}

static void
wg_if_detach(struct wg_softc *wg)
{
struct ifnet *ifp = &wg->wg_if;

bpf_detach(ifp);
if_detach(ifp);
}

static int
wg_clone_create(struct if_clone *ifc, int unit)
{
struct wg_softc *wg;
int error;

wg_guarantee_initialized();

error = wg_count_inc();
if (error)
return error;

wg = kmem_zalloc(sizeof(*wg), KM_SLEEP);

if_initname(&wg->wg_if, ifc->ifc_name, unit);

PSLIST_INIT(&wg->wg_peers);
wg->wg_peers_bypubkey = thmap_create(0, NULL, THMAP_NOCOPY);
wg->wg_peers_byname = thmap_create(0, NULL, THMAP_NOCOPY);
wg->wg_sessions_byindex = thmap_create(0, NULL, THMAP_NOCOPY);
wg->wg_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
wg->wg_intr_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_SOFTNET);
wg->wg_rwlock = rw_obj_alloc();
threadpool_job_init(&wg->wg_job, wg_job, wg->wg_intr_lock,
"%s", if_name(&wg->wg_if));
wg->wg_ops = &wg_ops_rumpkernel;

error = threadpool_get(&wg->wg_threadpool, PRI_NONE);
if (error)
goto fail0;

#ifdef INET
error = wg_socreate(wg, AF_INET, &wg->wg_so4);
if (error)
goto fail1;
rn_inithead((void **)&wg->wg_rtable_ipv4,
offsetof(struct sockaddr_in, sin_addr) * NBBY);
#endif
#ifdef INET6
error = wg_socreate(wg, AF_INET6, &wg->wg_so6);
if (error)
goto fail2;
rn_inithead((void **)&wg->wg_rtable_ipv6,
offsetof(struct sockaddr_in6, sin6_addr) * NBBY);
#endif

error = wg_if_attach(wg);
if (error)
goto fail3;

return 0;

fail4: __unused
wg_destroy_all_peers(wg);
wg_if_detach(wg);
fail3:
#ifdef INET6
solock(wg->wg_so6);
wg->wg_so6->so_rcv.sb_flags &= ~SB_UPCALL;
sounlock(wg->wg_so6);
#endif
#ifdef INET
solock(wg->wg_so4);
wg->wg_so4->so_rcv.sb_flags &= ~SB_UPCALL;
sounlock(wg->wg_so4);
#endif
mutex_enter(wg->wg_intr_lock);
threadpool_cancel_job(wg->wg_threadpool, &wg->wg_job);
mutex_exit(wg->wg_intr_lock);
#ifdef INET6
if (wg->wg_rtable_ipv6 != NULL)
free(wg->wg_rtable_ipv6, M_RTABLE);
soclose(wg->wg_so6);
fail2:
#endif
#ifdef INET
if (wg->wg_rtable_ipv4 != NULL)
free(wg->wg_rtable_ipv4, M_RTABLE);
soclose(wg->wg_so4);
fail1:
#endif
threadpool_put(wg->wg_threadpool, PRI_NONE);
fail0: threadpool_job_destroy(&wg->wg_job);
rw_obj_free(wg->wg_rwlock);
mutex_obj_free(wg->wg_intr_lock);
mutex_obj_free(wg->wg_lock);
thmap_destroy(wg->wg_sessions_byindex);
thmap_destroy(wg->wg_peers_byname);
thmap_destroy(wg->wg_peers_bypubkey);
PSLIST_DESTROY(&wg->wg_peers);
kmem_free(wg, sizeof(*wg));
wg_count_dec();
return error;
}

static int
wg_clone_destroy(struct ifnet *ifp)
{
struct wg_softc *wg = container_of(ifp, struct wg_softc, wg_if);

#ifdef WG_RUMPKERNEL
if (wg_user_mode(wg)) {
rumpuser_wg_destroy(wg->wg_user);
wg->wg_user = NULL;
}
#endif

wg_destroy_all_peers(wg);
wg_if_detach(wg);
#ifdef INET6
solock(wg->wg_so6);
wg->wg_so6->so_rcv.sb_flags &= ~SB_UPCALL;
sounlock(wg->wg_so6);
#endif
#ifdef INET
solock(wg->wg_so4);
wg->wg_so4->so_rcv.sb_flags &= ~SB_UPCALL;
sounlock(wg->wg_so4);
#endif
mutex_enter(wg->wg_intr_lock);
threadpool_cancel_job(wg->wg_threadpool, &wg->wg_job);
mutex_exit(wg->wg_intr_lock);
#ifdef INET6
if (wg->wg_rtable_ipv6 != NULL)
free(wg->wg_rtable_ipv6, M_RTABLE);
soclose(wg->wg_so6);
#endif
#ifdef INET
if (wg->wg_rtable_ipv4 != NULL)
free(wg->wg_rtable_ipv4, M_RTABLE);
soclose(wg->wg_so4);
#endif
threadpool_put(wg->wg_threadpool, PRI_NONE);
threadpool_job_destroy(&wg->wg_job);
rw_obj_free(wg->wg_rwlock);
mutex_obj_free(wg->wg_intr_lock);
mutex_obj_free(wg->wg_lock);
thmap_destroy(wg->wg_sessions_byindex);
thmap_destroy(wg->wg_peers_byname);
thmap_destroy(wg->wg_peers_bypubkey);
PSLIST_DESTROY(&wg->wg_peers);
kmem_free(wg, sizeof(*wg));
wg_count_dec();

return 0;
}

static struct wg_peer *
wg_pick_peer_by_sa(struct wg_softc *wg, const struct sockaddr *sa,
struct psref *psref)
{
struct radix_node_head *rnh;
struct radix_node *rn;
struct wg_peer *wgp = NULL;
struct wg_allowedip *wga;

#ifdef WG_DEBUG_LOG
char addrstr[128];
sockaddr_format(sa, addrstr, sizeof(addrstr));
WG_DLOG("sa=%s\n", addrstr);
#endif

rw_enter(wg->wg_rwlock, RW_READER);

rnh = wg_rnh(wg, sa->sa_family);
if (rnh == NULL)
goto out;

rn = rnh->rnh_matchaddr(sa, rnh);
if (rn == NULL || (rn->rn_flags & RNF_ROOT) != 0)
goto out;

WG_TRACE("success");

wga = container_of(rn, struct wg_allowedip, wga_nodes[0]);
wgp = wga->wga_peer;
wg_get_peer(wgp, psref);

out:
rw_exit(wg->wg_rwlock);
return wgp;
}

static void
wg_fill_msg_data(struct wg_softc *wg, struct wg_peer *wgp,
struct wg_session *wgs, struct wg_msg_data *wgmd)
{

memset(wgmd, 0, sizeof(*wgmd));
wgmd->wgmd_type = htole32(WG_MSG_TYPE_DATA);
wgmd->wgmd_receiver = wgs->wgs_remote_index;
/* [W] 5.4.6: msg.counter := Nm^send */
/* [W] 5.4.6: Nm^send := Nm^send + 1 */
wgmd->wgmd_counter = htole64(wg_session_inc_send_counter(wgs));
WG_DLOG("counter=%"PRIu64"\n", le64toh(wgmd->wgmd_counter));
}

static int
wg_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
const struct rtentry *rt)
{
struct wg_softc *wg = ifp->if_softc;
struct wg_peer *wgp = NULL;
struct psref wgp_psref;
int bound;
int error;

bound = curlwp_bind();

/* TODO make the nest limit configurable via sysctl */
error = if_tunnel_check_nesting(ifp, m, 1);
if (error) {
WGLOG(LOG_ERR,
"%s: tunneling loop detected and packet dropped\n",
if_name(&wg->wg_if));
goto out0;
}

#ifdef ALTQ
bool altq = atomic_load_relaxed(&ifp->if_snd.altq_flags)
& ALTQF_ENABLED;
if (altq)
IFQ_CLASSIFY(&ifp->if_snd, m, dst->sa_family);
#endif

bpf_mtap_af(ifp, dst->sa_family, m, BPF_D_OUT);

m->m_flags &= ~(M_BCAST|M_MCAST);

wgp = wg_pick_peer_by_sa(wg, dst, &wgp_psref);
if (wgp == NULL) {
WG_TRACE("peer not found");
error = EHOSTUNREACH;
goto out0;
}

/* Clear checksum-offload flags. */
m->m_pkthdr.csum_flags = 0;
m->m_pkthdr.csum_data = 0;

/* Toss it in the queue. */
#ifdef ALTQ
if (altq) {
mutex_enter(ifp->if_snd.ifq_lock);
if (ALTQ_IS_ENABLED(&ifp->if_snd)) {
M_SETCTX(m, wgp);
ALTQ_ENQUEUE(&ifp->if_snd, m, error);
m = NULL; /* consume */
}
mutex_exit(ifp->if_snd.ifq_lock);
if (m == NULL) {
wg_start(ifp);
goto out1;
}
}
#endif
kpreempt_disable();
const uint32_t h = curcpu()->ci_index; // pktq_rps_hash(m)
M_SETCTX(m, wgp);
if (__predict_false(!pktq_enqueue(wg_pktq, m, h))) {
WGLOG(LOG_ERR, "%s: pktq full, dropping\n",
if_name(&wg->wg_if));
error = ENOBUFS;
goto out2;
}
m = NULL; /* consumed */
error = 0;
out2: kpreempt_enable();

#ifdef ALTQ
out1:
#endif
wg_put_peer(wgp, &wgp_psref);
out0: m_freem(m);
curlwp_bindx(bound);
return error;
}

static int
wg_send_data(struct wg_peer *wgp, struct mbuf *m)
{
struct psref psref;
struct wg_sockaddr *wgsa;
int error;
struct socket *so;

wgsa = wg_get_endpoint_sa(wgp, &psref);
so = wg_get_so_by_peer(wgp, wgsa);
solock(so);
switch (wgsatosa(wgsa)->sa_family) {
#ifdef INET
case AF_INET:
error = udp_send(so, m, wgsatosa(wgsa), NULL, curlwp);
break;
#endif
#ifdef INET6
case AF_INET6:
error = udp6_output(sotoinpcb(so), m, wgsatosin6(wgsa),
NULL, curlwp);
break;
#endif
default:
m_freem(m);
error = EPFNOSUPPORT;
}
sounlock(so);
wg_put_sa(wgp, wgsa, &psref);

return error;
}

/* Inspired by pppoe_get_mbuf */
static struct mbuf *
wg_get_mbuf(size_t leading_len, size_t len)
{
struct mbuf *m;

KASSERT(leading_len <= MCLBYTES);
KASSERT(len <= MCLBYTES - leading_len);

m = m_gethdr(M_DONTWAIT, MT_DATA);
if (m == NULL)
return NULL;
if (len + leading_len > MHLEN) {
m_clget(m, M_DONTWAIT);
if ((m->m_flags & M_EXT) == 0) {
m_free(m);
return NULL;
}
}
m->m_data += leading_len;
m->m_pkthdr.len = m->m_len = len;

return m;
}

static void
wg_send_data_msg(struct wg_peer *wgp, struct wg_session *wgs, struct mbuf *m)
{
struct wg_softc *wg = wgp->wgp_sc;
int error;
size_t inner_len, padded_len, encrypted_len;
char *padded_buf = NULL;
size_t mlen;
struct wg_msg_data *wgmd;
bool free_padded_buf = false;
struct mbuf *n;
size_t leading_len = max_hdr + sizeof(struct udphdr);

mlen = m_length(m);
inner_len = mlen;
padded_len = roundup(mlen, 16);
encrypted_len = padded_len + WG_AUTHTAG_LEN;
WG_DLOG("inner=%zu, padded=%zu, encrypted_len=%zu\n",
inner_len, padded_len, encrypted_len);
if (mlen != 0) {
bool success;
success = m_ensure_contig(&m, padded_len);
if (success) {
padded_buf = mtod(m, char *);
} else {
padded_buf = kmem_intr_alloc(padded_len, KM_NOSLEEP);
if (padded_buf == NULL) {
error = ENOBUFS;
goto out;
}
free_padded_buf = true;
m_copydata(m, 0, mlen, padded_buf);
}
memset(padded_buf + mlen, 0, padded_len - inner_len);
}

n = wg_get_mbuf(leading_len, sizeof(*wgmd) + encrypted_len);
if (n == NULL) {
error = ENOBUFS;
goto out;
}
KASSERT(n->m_len >= sizeof(*wgmd));
wgmd = mtod(n, struct wg_msg_data *);
wg_fill_msg_data(wg, wgp, wgs, wgmd);

/* [W] 5.4.6: AEAD(Tm^send, Nm^send, P, e) */
wg_algo_aead_enc((char *)wgmd + sizeof(*wgmd), encrypted_len,
wgs->wgs_tkey_send, le64toh(wgmd->wgmd_counter),
padded_buf, padded_len,
NULL, 0);

error = wg->wg_ops->send_data_msg(wgp, n); /* consumes n */
if (error) {
WG_DLOG("send_data_msg failed, error=%d\n", error);
goto out;
}

/*
* Packet was sent out -- count it in the interface statistics.
*/
if_statadd(&wg->wg_if, if_obytes, mlen);
if_statinc(&wg->wg_if, if_opackets);

/*
* Record when we last sent data, for determining when we need
* to send a passive keepalive.
*
* Other logic assumes that wgs_time_last_data_sent is zero iff
* we have never sent data on this session. Early at boot, if
* wg(4) starts operating within <1sec, or after 136 years of
* uptime, we may observe time_uptime32 = 0. In that case,
* pretend we observed 1 instead. That way, we correctly
* indicate we have sent data on this session; the only logic
* this might adversely affect is the keepalive timeout
* detection, which might spuriously send a keepalive during
* one second every 136 years. All of this is very silly, of
* course, but the cost to guaranteeing wgs_time_last_data_sent
* is nonzero is negligible here.
*/
const uint32_t now = time_uptime32;
atomic_store_relaxed(&wgs->wgs_time_last_data_sent, MAX(now, 1));

/*
* Check rekey-after-time.
*/
if (wgs->wgs_is_initiator &&
now - wgs->wgs_time_established >= wg_rekey_after_time) {
/*
* [W] 6.2 Transport Message Limits
* "if a peer is the initiator of a current secure
* session, WireGuard will send a handshake initiation
* message to begin a new secure session if, after
* transmitting a transport data message, the current
* secure session is REKEY-AFTER-TIME seconds old,"
*/
WG_TRACE("rekey after time");
atomic_store_relaxed(&wgs->wgs_force_rekey, true);
wg_schedule_peer_task(wgp, WGP_TASK_SEND_INIT_MESSAGE);
}

/*
* Check rekey-after-messages.
*/
if (wg_session_get_send_counter(wgs) >= wg_rekey_after_messages) {
/*
* [W] 6.2 Transport Message Limits
* "WireGuard will try to create a new session, by
* sending a handshake initiation message (section
* 5.4.2), after it has sent REKEY-AFTER-MESSAGES
* transport data messages..."
*/
WG_TRACE("rekey after messages");
atomic_store_relaxed(&wgs->wgs_force_rekey, true);
wg_schedule_peer_task(wgp, WGP_TASK_SEND_INIT_MESSAGE);
}

out: m_freem(m);
if (free_padded_buf)
kmem_intr_free(padded_buf, padded_len);
}

static void
wg_input(struct ifnet *ifp, struct mbuf *m, const int af)
{
pktqueue_t *pktq;
size_t pktlen;

KASSERT(af == AF_INET || af == AF_INET6);

WG_TRACE("");

m_set_rcvif(m, ifp);
pktlen = m->m_pkthdr.len;

bpf_mtap_af(ifp, af, m, BPF_D_IN);

switch (af) {
#ifdef INET
case AF_INET:
pktq = ip_pktq;
break;
#endif
#ifdef INET6
case AF_INET6:
pktq = ip6_pktq;
break;
#endif
default:
panic("invalid af=%d", af);
}

kpreempt_disable();
const u_int h = curcpu()->ci_index;
if (__predict_true(pktq_enqueue(pktq, m, h))) {
if_statadd(ifp, if_ibytes, pktlen);
if_statinc(ifp, if_ipackets);
} else {
m_freem(m);
}
kpreempt_enable();
}

static void
wg_calc_pubkey(uint8_t pubkey[static WG_STATIC_KEY_LEN],
const uint8_t privkey[static WG_STATIC_KEY_LEN])
{

crypto_scalarmult_base(pubkey, privkey);
}

static int
wg_rtable_add_route(struct wg_softc *wg, struct wg_allowedip *wga)
{
struct radix_node_head *rnh;
struct radix_node *rn;
int error = 0;

rw_enter(wg->wg_rwlock, RW_WRITER);
rnh = wg_rnh(wg, wga->wga_family);
KASSERT(rnh != NULL);
rn = rnh->rnh_addaddr(&wga->wga_sa_addr, &wga->wga_sa_mask, rnh,
wga->wga_nodes);
rw_exit(wg->wg_rwlock);

if (rn == NULL)
error = EEXIST;

return error;
}

static int
wg_handle_prop_peer(struct wg_softc *wg, prop_dictionary_t peer,
struct wg_peer **wgpp)
{
int error = 0;
const void *pubkey;
size_t pubkey_len;
const void *psk;
size_t psk_len;
const char *name = NULL;

if (prop_dictionary_get_string(peer, "name", &name)) {
if (strlen(name) > WG_PEER_NAME_MAXLEN) {
error = EINVAL;
goto out;
}
}

if (!prop_dictionary_get_data(peer, "public_key",
&pubkey, &pubkey_len)) {
error = EINVAL;
goto out;
}
#ifdef WG_DEBUG_DUMP
if (wg_debug & WG_DEBUG_FLAGS_DUMP) {
char *hex = gethexdump(pubkey, pubkey_len);
log(LOG_DEBUG, "pubkey=%p, pubkey_len=%zu\n%s\n",
pubkey, pubkey_len, hex);
puthexdump(hex, pubkey, pubkey_len);
}
#endif

struct wg_peer *wgp = wg_alloc_peer(wg);
memcpy(wgp->wgp_pubkey, pubkey, sizeof(wgp->wgp_pubkey));
if (name != NULL)
strncpy(wgp->wgp_name, name, sizeof(wgp->wgp_name));

if (prop_dictionary_get_data(peer, "preshared_key", &psk, &psk_len)) {
if (psk_len != sizeof(wgp->wgp_psk)) {
error = EINVAL;
goto out;
}
memcpy(wgp->wgp_psk, psk, sizeof(wgp->wgp_psk));
}

const void *addr;
size_t addr_len;
struct wg_sockaddr *wgsa = wgp->wgp_endpoint;

if (!prop_dictionary_get_data(peer, "endpoint", &addr, &addr_len))
goto skip_endpoint;
if (addr_len < sizeof(*wgsatosa(wgsa)) ||
addr_len > sizeof(*wgsatoss(wgsa))) {
error = EINVAL;
goto out;
}
memcpy(wgsatoss(wgsa), addr, addr_len);
switch (wgsa_family(wgsa)) {
#ifdef INET
case AF_INET:
break;
#endif
#ifdef INET6
case AF_INET6:
break;
#endif
default:
error = EPFNOSUPPORT;
goto out;
}
if (addr_len != sockaddr_getsize_by_family(wgsa_family(wgsa))) {
error = EINVAL;
goto out;
}
{
char addrstr[128];
sockaddr_format(wgsatosa(wgsa), addrstr, sizeof(addrstr));
WG_DLOG("addr=%s\n", addrstr);
}
wgp->wgp_endpoint_available = true;

prop_array_t allowedips;
skip_endpoint:
allowedips = prop_dictionary_get(peer, "allowedips");
if (allowedips == NULL)
goto skip;

prop_object_iterator_t _it = prop_array_iterator(allowedips);
prop_dictionary_t prop_allowedip;
int j = 0;
while ((prop_allowedip = prop_object_iterator_next(_it)) != NULL) {
struct wg_allowedip *wga = &wgp->wgp_allowedips[j];

if (!prop_dictionary_get_int(prop_allowedip, "family",
&wga->wga_family))
continue;
if (!prop_dictionary_get_data(prop_allowedip, "ip",
&addr, &addr_len))
continue;
if (!prop_dictionary_get_uint8(prop_allowedip, "cidr",
&wga->wga_cidr))
continue;

switch (wga->wga_family) {
#ifdef INET
case AF_INET: {
struct sockaddr_in sin;
char addrstr[128];
struct in_addr mask;
struct sockaddr_in sin_mask;

if (addr_len != sizeof(struct in_addr))
return EINVAL;
memcpy(&wga->wga_addr4, addr, addr_len);

sockaddr_in_init(&sin, (const struct in_addr *)addr,
0);
sockaddr_copy(&wga->wga_sa_addr,
sizeof(sin), sintosa(&sin));

sockaddr_format(sintosa(&sin),
addrstr, sizeof(addrstr));
WG_DLOG("addr=%s/%d\n", addrstr, wga->wga_cidr);

in_len2mask(&mask, wga->wga_cidr);
sockaddr_in_init(&sin_mask, &mask, 0);
sockaddr_copy(&wga->wga_sa_mask,
sizeof(sin_mask), sintosa(&sin_mask));

break;
}
#endif
#ifdef INET6
case AF_INET6: {
struct sockaddr_in6 sin6;
char addrstr[128];
struct in6_addr mask;
struct sockaddr_in6 sin6_mask;

if (addr_len != sizeof(struct in6_addr))
return EINVAL;
memcpy(&wga->wga_addr6, addr, addr_len);

sockaddr_in6_init(&sin6, (const struct in6_addr *)addr,
0, 0, 0);
sockaddr_copy(&wga->wga_sa_addr,
sizeof(sin6), sin6tosa(&sin6));

sockaddr_format(sin6tosa(&sin6),
addrstr, sizeof(addrstr));
WG_DLOG("addr=%s/%d\n", addrstr, wga->wga_cidr);

in6_prefixlen2mask(&mask, wga->wga_cidr);
sockaddr_in6_init(&sin6_mask, &mask, 0, 0, 0);
sockaddr_copy(&wga->wga_sa_mask,
sizeof(sin6_mask), sin6tosa(&sin6_mask));

break;
}
#endif
default:
error = EINVAL;
goto out;
}
wga->wga_peer = wgp;

error = wg_rtable_add_route(wg, wga);
if (error != 0)
goto out;

j++;
}
wgp->wgp_n_allowedips = j;
skip:
*wgpp = wgp;
out:
return error;
}

static int
wg_alloc_prop_buf(char **_buf, struct ifdrv *ifd)
{
int error;
char *buf;

WG_DLOG("buf=%p, len=%zu\n", ifd->ifd_data, ifd->ifd_len);
if (ifd->ifd_len >= WG_MAX_PROPLEN)
return E2BIG;
buf = kmem_alloc(ifd->ifd_len + 1, KM_SLEEP);
error = copyin(ifd->ifd_data, buf, ifd->ifd_len);
if (error != 0)
return error;
buf[ifd->ifd_len] = '\0';
#ifdef WG_DEBUG_DUMP
if (wg_debug & WG_DEBUG_FLAGS_DUMP) {
log(LOG_DEBUG, "%.*s\n", (int)MIN(INT_MAX, ifd->ifd_len),
(const char *)buf);
}
#endif
*_buf = buf;
return 0;
}

static int
wg_ioctl_set_private_key(struct wg_softc *wg, struct ifdrv *ifd)
{
int error;
prop_dictionary_t prop_dict;
char *buf = NULL;
const void *privkey;
size_t privkey_len;

error = wg_alloc_prop_buf(&buf, ifd);
if (error != 0)
return error;
error = EINVAL;
prop_dict = prop_dictionary_internalize(buf);
if (prop_dict == NULL)
goto out;
if (!prop_dictionary_get_data(prop_dict, "private_key",
&privkey, &privkey_len))
goto out;
#ifdef WG_DEBUG_DUMP
if (wg_debug & WG_DEBUG_FLAGS_DUMP) {
char *hex = gethexdump(privkey, privkey_len);
log(LOG_DEBUG, "privkey=%p, privkey_len=%zu\n%s\n",
privkey, privkey_len, hex);
puthexdump(hex, privkey, privkey_len);
}
#endif
if (privkey_len != WG_STATIC_KEY_LEN)
goto out;
memcpy(wg->wg_privkey, privkey, WG_STATIC_KEY_LEN);
wg_calc_pubkey(wg->wg_pubkey, wg->wg_privkey);
error = 0;

out:
kmem_free(buf, ifd->ifd_len + 1);
return error;
}

static int
wg_ioctl_set_listen_port(struct wg_softc *wg, struct ifdrv *ifd)
{
int error;
prop_dictionary_t prop_dict;
char *buf = NULL;
uint16_t port;

error = wg_alloc_prop_buf(&buf, ifd);
if (error != 0)
return error;
error = EINVAL;
prop_dict = prop_dictionary_internalize(buf);
if (prop_dict == NULL)
goto out;
if (!prop_dictionary_get_uint16(prop_dict, "listen_port", &port))
goto out;

error = wg->wg_ops->bind_port(wg, (uint16_t)port);

out:
kmem_free(buf, ifd->ifd_len + 1);
return error;
}

static int
wg_ioctl_add_peer(struct wg_softc *wg, struct ifdrv *ifd)
{
int error;
prop_dictionary_t prop_dict;
char *buf = NULL;
struct wg_peer *wgp = NULL, *wgp0 __diagused;

error = wg_alloc_prop_buf(&buf, ifd);
if (error != 0)
return error;
error = EINVAL;
prop_dict = prop_dictionary_internalize(buf);
if (prop_dict == NULL)
goto out;

error = wg_handle_prop_peer(wg, prop_dict, &wgp);
if (error != 0)
goto out;

mutex_enter(wg->wg_lock);
if (thmap_get(wg->wg_peers_bypubkey, wgp->wgp_pubkey,
sizeof(wgp->wgp_pubkey)) != NULL ||
(wgp->wgp_name[0] &&
thmap_get(wg->wg_peers_byname, wgp->wgp_name,
strlen(wgp->wgp_name)) != NULL)) {
mutex_exit(wg->wg_lock);
wg_destroy_peer(wgp);
error = EEXIST;
goto out;
}
wgp0 = thmap_put(wg->wg_peers_bypubkey, wgp->wgp_pubkey,
sizeof(wgp->wgp_pubkey), wgp);
KASSERT(wgp0 == wgp);
if (wgp->wgp_name[0]) {
wgp0 = thmap_put(wg->wg_peers_byname, wgp->wgp_name,
strlen(wgp->wgp_name), wgp);
KASSERT(wgp0 == wgp);
}
WG_PEER_WRITER_INSERT_HEAD(wgp, wg);
wg->wg_npeers++;
mutex_exit(wg->wg_lock);

if_link_state_change(&wg->wg_if, LINK_STATE_UP);

out:
kmem_free(buf, ifd->ifd_len + 1);
return error;
}

static int
wg_ioctl_delete_peer(struct wg_softc *wg, struct ifdrv *ifd)
{
int error;
prop_dictionary_t prop_dict;
char *buf = NULL;
const char *name;

error = wg_alloc_prop_buf(&buf, ifd);
if (error != 0)
return error;
error = EINVAL;
prop_dict = prop_dictionary_internalize(buf);
if (prop_dict == NULL)
goto out;

if (!prop_dictionary_get_string(prop_dict, "name", &name))
goto out;
if (strlen(name) > WG_PEER_NAME_MAXLEN)
goto out;

error = wg_destroy_peer_name(wg, name);
out:
kmem_free(buf, ifd->ifd_len + 1);
return error;
}

static bool
wg_is_authorized(struct wg_softc *wg, u_long cmd)
{
int au = cmd == SIOCGDRVSPEC ?
KAUTH_REQ_NETWORK_INTERFACE_WG_GETPRIV :
KAUTH_REQ_NETWORK_INTERFACE_WG_SETPRIV;
return kauth_authorize_network(kauth_cred_get(),
KAUTH_NETWORK_INTERFACE_WG, au, &wg->wg_if,
(void *)cmd, NULL) == 0;
}

static int
wg_ioctl_get(struct wg_softc *wg, struct ifdrv *ifd)
{
int error = ENOMEM;
prop_dictionary_t prop_dict;
prop_array_t peers = NULL;
char *buf;
struct wg_peer *wgp;
int s, i;

prop_dict = prop_dictionary_create();
if (prop_dict == NULL)
goto error;

if (wg_is_authorized(wg, SIOCGDRVSPEC)) {
if (!prop_dictionary_set_data(prop_dict, "private_key",
wg->wg_privkey, WG_STATIC_KEY_LEN))
goto error;
}

if (wg->wg_listen_port != 0) {
if (!prop_dictionary_set_uint16(prop_dict, "listen_port",
wg->wg_listen_port))
goto error;
}

if (wg->wg_npeers == 0)
goto skip_peers;

peers = prop_array_create();
if (peers == NULL)
goto error;

s = pserialize_read_enter();
i = 0;
WG_PEER_READER_FOREACH(wgp, wg) {
struct wg_sockaddr *wgsa;
struct psref wgp_psref, wgsa_psref;
prop_dictionary_t prop_peer;

wg_get_peer(wgp, &wgp_psref);
pserialize_read_exit(s);

prop_peer = prop_dictionary_create();
if (prop_peer == NULL)
goto next;

if (strlen(wgp->wgp_name) > 0) {
if (!prop_dictionary_set_string(prop_peer, "name",
wgp->wgp_name))
goto next;
}

if (!prop_dictionary_set_data(prop_peer, "public_key",
wgp->wgp_pubkey, sizeof(wgp->wgp_pubkey)))
goto next;

uint8_t psk_zero[WG_PRESHARED_KEY_LEN] = {0};
if (!consttime_memequal(wgp->wgp_psk, psk_zero,
sizeof(wgp->wgp_psk))) {
if (wg_is_authorized(wg, SIOCGDRVSPEC)) {
if (!prop_dictionary_set_data(prop_peer,
"preshared_key",
wgp->wgp_psk, sizeof(wgp->wgp_psk)))
goto next;
}
}

wgsa = wg_get_endpoint_sa(wgp, &wgsa_psref);
CTASSERT(AF_UNSPEC == 0);
if (wgsa_family(wgsa) != 0 /*AF_UNSPEC*/ &&
!prop_dictionary_set_data(prop_peer, "endpoint",
wgsatoss(wgsa),
sockaddr_getsize_by_family(wgsa_family(wgsa)))) {
wg_put_sa(wgp, wgsa, &wgsa_psref);
goto next;
}
wg_put_sa(wgp, wgsa, &wgsa_psref);

const struct timespec *t = &wgp->wgp_last_handshake_time;

if (!prop_dictionary_set_uint64(prop_peer,
"last_handshake_time_sec", (uint64_t)t->tv_sec))
goto next;
if (!prop_dictionary_set_uint32(prop_peer,
"last_handshake_time_nsec", (uint32_t)t->tv_nsec))
goto next;

if (wgp->wgp_n_allowedips == 0)
goto skip_allowedips;

prop_array_t allowedips = prop_array_create();
if (allowedips == NULL)
goto next;
for (int j = 0; j < wgp->wgp_n_allowedips; j++) {
struct wg_allowedip *wga = &wgp->wgp_allowedips[j];
prop_dictionary_t prop_allowedip;

prop_allowedip = prop_dictionary_create();
if (prop_allowedip == NULL)
break;

if (!prop_dictionary_set_int(prop_allowedip, "family",
wga->wga_family))
goto _next;
if (!prop_dictionary_set_uint8(prop_allowedip, "cidr",
wga->wga_cidr))
goto _next;

switch (wga->wga_family) {
#ifdef INET
case AF_INET:
if (!prop_dictionary_set_data(prop_allowedip,
"ip", &wga->wga_addr4,
sizeof(wga->wga_addr4)))
goto _next;
break;
#endif
#ifdef INET6
case AF_INET6:
if (!prop_dictionary_set_data(prop_allowedip,
"ip", &wga->wga_addr6,
sizeof(wga->wga_addr6)))
goto _next;
break;
#endif
default:
panic("invalid af=%d", wga->wga_family);
}
prop_array_set(allowedips, j, prop_allowedip);
_next:
prop_object_release(prop_allowedip);
}
prop_dictionary_set(prop_peer, "allowedips", allowedips);
prop_object_release(allowedips);

skip_allowedips:

prop_array_set(peers, i, prop_peer);
next:
if (prop_peer)
prop_object_release(prop_peer);
i++;

s = pserialize_read_enter();
wg_put_peer(wgp, &wgp_psref);
}
pserialize_read_exit(s);

prop_dictionary_set(prop_dict, "peers", peers);
prop_object_release(peers);
peers = NULL;

skip_peers:
buf = prop_dictionary_externalize(prop_dict);
if (buf == NULL)
goto error;
if (ifd->ifd_len < (strlen(buf) + 1)) {
error = EINVAL;
goto error;
}
error = copyout(buf, ifd->ifd_data, strlen(buf) + 1);

free(buf, 0);
error:
if (peers != NULL)
prop_object_release(peers);
if (prop_dict != NULL)
prop_object_release(prop_dict);

return error;
}

static int
wg_ioctl(struct ifnet *ifp, u_long cmd, void *data)
{
struct wg_softc *wg = ifp->if_softc;
struct ifreq *ifr = data;
struct ifaddr *ifa = data;
struct ifdrv *ifd = data;
int error = 0;

switch (cmd) {
case SIOCINITIFADDR:
if (ifa->ifa_addr->sa_family != AF_LINK &&
(ifp->if_flags & (IFF_UP | IFF_RUNNING)) !=
(IFF_UP | IFF_RUNNING)) {
ifp->if_flags |= IFF_UP;
error = if_init(ifp);
}
return error;
case SIOCADDMULTI:
case SIOCDELMULTI:
switch (ifr->ifr_addr.sa_family) {
#ifdef INET
case AF_INET: /* IP supports Multicast */
break;
#endif
#ifdef INET6
case AF_INET6: /* IP6 supports Multicast */
break;
#endif
default: /* Other protocols doesn't support Multicast */
error = EAFNOSUPPORT;
break;
}
return error;
case SIOCSDRVSPEC:
if (!wg_is_authorized(wg, cmd)) {
return EPERM;
}
switch (ifd->ifd_cmd) {
case WG_IOCTL_SET_PRIVATE_KEY:
error = wg_ioctl_set_private_key(wg, ifd);
break;
case WG_IOCTL_SET_LISTEN_PORT:
error = wg_ioctl_set_listen_port(wg, ifd);
break;
case WG_IOCTL_ADD_PEER:
error = wg_ioctl_add_peer(wg, ifd);
break;
case WG_IOCTL_DELETE_PEER:
error = wg_ioctl_delete_peer(wg, ifd);
break;
default:
error = EINVAL;
break;
}
return error;
case SIOCGDRVSPEC:
return wg_ioctl_get(wg, ifd);
case SIOCSIFFLAGS:
if ((error = ifioctl_common(ifp, cmd, data)) != 0)
break;
switch (ifp->if_flags & (IFF_UP|IFF_RUNNING)) {
case IFF_RUNNING:
/*
* If interface is marked down and it is running,
* then stop and disable it.
*/
if_stop(ifp, 1);
break;
case IFF_UP:
/*
* If interface is marked up and it is stopped, then
* start it.
*/
error = if_init(ifp);
break;
default:
break;
}
return error;
#ifdef WG_RUMPKERNEL
case SIOCSLINKSTR:
error = wg_ioctl_linkstr(wg, ifd);
if (error)
return error;
wg->wg_ops = &wg_ops_rumpuser;
return 0;
#endif
default:
break;
}

error = ifioctl_common(ifp, cmd, data);

#ifdef WG_RUMPKERNEL
if (!wg_user_mode(wg))
return error;

/* Do the same to the corresponding tun device on the host */
/*
* XXX Actually the command has not been handled yet. It
* will be handled via pr_ioctl form doifioctl later.
*/
switch (cmd) {
#ifdef INET
case SIOCAIFADDR:
case SIOCDIFADDR: {
struct in_aliasreq _ifra = *(const struct in_aliasreq *)data;
struct in_aliasreq *ifra = &_ifra;
KASSERT(error == ENOTTY);
strncpy(ifra->ifra_name, rumpuser_wg_get_tunname(wg->wg_user),
IFNAMSIZ);
error = rumpuser_wg_ioctl(wg->wg_user, cmd, ifra, AF_INET);
if (error == 0)
error = ENOTTY;
break;
}
#endif
#ifdef INET6
case SIOCAIFADDR_IN6:
case SIOCDIFADDR_IN6: {
struct in6_aliasreq _ifra = *(const struct in6_aliasreq *)data;
struct in6_aliasreq *ifra = &_ifra;
KASSERT(error == ENOTTY);
strncpy(ifra->ifra_name, rumpuser_wg_get_tunname(wg->wg_user),
IFNAMSIZ);
error = rumpuser_wg_ioctl(wg->wg_user, cmd, ifra, AF_INET6);
if (error == 0)
error = ENOTTY;
break;
}
#endif
default:
break;
}
#endif /* WG_RUMPKERNEL */

return error;
}

static int
wg_init(struct ifnet *ifp)
{

ifp->if_flags |= IFF_RUNNING;

/* TODO flush pending packets. */
return 0;
}

#ifdef ALTQ
static void
wg_start(struct ifnet *ifp)
{
struct mbuf *m;

for (;;) {
IFQ_DEQUEUE(&ifp->if_snd, m);
if (m == NULL)
break;

kpreempt_disable();
const uint32_t h = curcpu()->ci_index; // pktq_rps_hash(m)
if (__predict_false(!pktq_enqueue(wg_pktq, m, h))) {
WGLOG(LOG_ERR, "%s: pktq full, dropping\n",
if_name(ifp));
m_freem(m);
}
kpreempt_enable();
}
}
#endif

static void
wg_stop(struct ifnet *ifp, int disable)
{

KASSERT((ifp->if_flags & IFF_RUNNING) != 0);
ifp->if_flags &= ~IFF_RUNNING;

/* Need to do something? */
}

#ifdef WG_DEBUG_PARAMS
SYSCTL_SETUP(sysctl_net_wg_setup, "sysctl net.wg setup")
{
const struct sysctlnode *node = NULL;

sysctl_createv(clog, 0, NULL, &node,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "wg",
SYSCTL_DESCR("wg(4)"),
NULL, 0, NULL, 0,
CTL_NET, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, &node, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_QUAD, "rekey_after_messages",
SYSCTL_DESCR("session liftime by messages"),
NULL, 0, &wg_rekey_after_messages, 0, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, &node, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "rekey_after_time",
SYSCTL_DESCR("session liftime"),
NULL, 0, &wg_rekey_after_time, 0, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, &node, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "rekey_timeout",
SYSCTL_DESCR("session handshake retry time"),
NULL, 0, &wg_rekey_timeout, 0, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, &node, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "rekey_attempt_time",
SYSCTL_DESCR("session handshake timeout"),
NULL, 0, &wg_rekey_attempt_time, 0, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, &node, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "keepalive_timeout",
SYSCTL_DESCR("keepalive timeout"),
NULL, 0, &wg_keepalive_timeout, 0, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, &node, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_BOOL, "force_underload",
SYSCTL_DESCR("force to detemine under load"),
NULL, 0, &wg_force_underload, 0, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, &node, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "debug",
SYSCTL_DESCR("set debug flags 1=log 2=trace 4=dump 8=packet"),
NULL, 0, &wg_debug, 0, CTL_CREATE, CTL_EOL);
}
#endif

#ifdef WG_RUMPKERNEL
static bool
wg_user_mode(struct wg_softc *wg)
{

return wg->wg_user != NULL;
}

static int
wg_ioctl_linkstr(struct wg_softc *wg, struct ifdrv *ifd)
{
struct ifnet *ifp = &wg->wg_if;
int error;

if (ifp->if_flags & IFF_UP)
return EBUSY;

if (ifd->ifd_cmd == IFLINKSTR_UNSET) {
/* XXX do nothing */
return 0;
} else if (ifd->ifd_cmd != 0) {
return EINVAL;
} else if (wg->wg_user != NULL) {
return EBUSY;
}

/* Assume \0 included */
if (ifd->ifd_len > IFNAMSIZ) {
return E2BIG;
} else if (ifd->ifd_len < 1) {
return EINVAL;
}

char tun_name[IFNAMSIZ];
error = copyinstr(ifd->ifd_data, tun_name, ifd->ifd_len, NULL);
if (error != 0)
return error;

if (strncmp(tun_name, "tun", 3) != 0)
return EINVAL;

error = rumpuser_wg_create(tun_name, wg, &wg->wg_user);

return error;
}

static int
wg_send_user(struct wg_peer *wgp, struct mbuf *m, bool handshake)
{
int error;
struct psref psref;
struct wg_sockaddr *wgsa;
struct wg_softc *wg = wgp->wgp_sc;
struct iovec iov[1];

wgsa = wg_get_endpoint_sa(wgp, &psref);

#ifdef WG_DEBUG_LOG
if (handshake) {
char addr[128];
sockaddr_format(wgsatosa(wgsa), addr, sizeof(addr));
WG_DLOG("send handshake msg to %s\n", addr);
}
#endif

iov[0].iov_base = mtod(m, void *);
iov[0].iov_len = m->m_len;

/* Send messages to a peer via an ordinary socket. */
error = rumpuser_wg_send_peer(wg->wg_user, wgsatosa(wgsa), iov, 1);

wg_put_sa(wgp, wgsa, &psref);

m_freem(m);

return error;
}

static int
wg_send_hs_user(struct wg_peer *wgp, struct mbuf *m)
{

return wg_send_user(wgp, m, /*handshake*/true);
}

static int
wg_send_data_user(struct wg_peer *wgp, struct mbuf *m)
{

return wg_send_user(wgp, m, /*handshake*/false);
}

static void
wg_input_user(struct ifnet *ifp, struct mbuf *m, const int af)
{
struct wg_softc *wg = ifp->if_softc;
struct iovec iov[2];
struct sockaddr_storage ss;

KASSERT(af == AF_INET || af == AF_INET6);

WG_TRACE("");

switch (af) {
#ifdef INET
case AF_INET: {
struct sockaddr_in *sin = (struct sockaddr_in *)&ss;
struct ip *ip;

KASSERT(m->m_len >= sizeof(struct ip));
ip = mtod(m, struct ip *);
sockaddr_in_init(sin, &ip->ip_dst, 0);
break;
}
#endif
#ifdef INET6
case AF_INET6: {
struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&ss;
struct ip6_hdr *ip6;

KASSERT(m->m_len >= sizeof(struct ip6_hdr));
ip6 = mtod(m, struct ip6_hdr *);
sockaddr_in6_init(sin6, &ip6->ip6_dst, 0, 0, 0);
break;
}
#endif
default:
goto out;
}

iov[0].iov_base = &ss;
iov[0].iov_len = ss.ss_len;
iov[1].iov_base = mtod(m, void *);
iov[1].iov_len = m->m_len;

WG_DUMP_BUF(iov[1].iov_base, iov[1].iov_len);

/* Send decrypted packets to users via a tun. */
rumpuser_wg_send_user(wg->wg_user, iov, 2);

out: m_freem(m);
}

static int
wg_bind_port_user(struct wg_softc *wg, const uint16_t port)
{
int error;
uint16_t old_port = wg->wg_listen_port;

if (port != 0 && old_port == port)
return 0;

error = rumpuser_wg_sock_bind(wg->wg_user, port);
if (error)
return error;

wg->wg_listen_port = port;
return 0;
}

/*
* Receive user packets.
*/
void
rumpkern_wg_recv_user(struct wg_softc *wg, struct iovec *iov, size_t iovlen)
{
struct ifnet *ifp = &wg->wg_if;
struct mbuf *m;
const struct sockaddr *dst;
int error;

WG_TRACE("");

dst = iov[0].iov_base;

m = m_gethdr(M_DONTWAIT, MT_DATA);
if (m == NULL)
return;
m->m_len = m->m_pkthdr.len = 0;
m_copyback(m, 0, iov[1].iov_len, iov[1].iov_base);

WG_DLOG("iov_len=%zu\n", iov[1].iov_len);
WG_DUMP_BUF(iov[1].iov_base, iov[1].iov_len);

error = wg_output(ifp, m, dst, NULL); /* consumes m */
if (error)
WG_DLOG("wg_output failed, error=%d\n", error);
}

/*
* Receive packets from a peer.
*/
void
rumpkern_wg_recv_peer(struct wg_softc *wg, struct iovec *iov, size_t iovlen)
{
struct mbuf *m;
const struct sockaddr *src;
int bound;

WG_TRACE("");

src = iov[0].iov_base;

m = m_gethdr(M_DONTWAIT, MT_DATA);
if (m == NULL)
return;
m->m_len = m->m_pkthdr.len = 0;
m_copyback(m, 0, iov[1].iov_len, iov[1].iov_base);

WG_DLOG("iov_len=%zu\n", iov[1].iov_len);
WG_DUMP_BUF(iov[1].iov_base, iov[1].iov_len);

bound = curlwp_bind();
wg_handle_packet(wg, m, src);
curlwp_bindx(bound);
}
#endif /* WG_RUMPKERNEL */

/*
* Module infrastructure
*/
#include "if_module.h"

IF_MODULE(MODULE_CLASS_DRIVER, wg, "sodium,blake2s")