* Copyright (c) 1992 Regents of the University of California.

/* $NetBSD: bootp.c,v 1.43 2019/04/05 20:09:29 christos Exp $ */

/*
* Copyright (c) 1992 Regents of the University of California.
* All rights reserved.
*
* This software was developed by the Computer Systems Engineering group
* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
* contributed to Berkeley.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Lawrence Berkeley Laboratory and its contributors.
* 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
*
* @(#) Header: bootp.c,v 1.4 93/09/11 03:13:51 leres Exp (LBL)
*/

#include <sys/param.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>

#ifdef _STANDALONE
#include <lib/libkern/libkern.h>
#else
#include <string.h>
#endif

#include "stand.h"
#include "net.h"
#include "bootp.h"

struct in_addr servip;
#ifdef SUPPORT_LINUX
char linuxcmdline[256];
#ifndef TAG_LINUX_CMDLINE
#define TAG_LINUX_CMDLINE 123
#endif
#endif

static n_long nmask, smask;

static satime_t bot;

static char vm_rfc1048[4] = VM_RFC1048;
#ifdef BOOTP_VEND_CMU
static char vm_cmu[4] = VM_CMU;
#endif

/* Local forwards */
static ssize_t bootpsend(struct iodesc *, void *, size_t);
static ssize_t bootprecv(struct iodesc *, void *, size_t, saseconds_t);
static int vend_rfc1048(u_char *, u_int);
#ifdef BOOTP_VEND_CMU
static void vend_cmu(u_char *);
#endif

#ifdef SUPPORT_DHCP
static char expected_dhcpmsgtype = -1, dhcp_ok;
struct in_addr dhcp_serverip;
#endif

/*
* Boot programs can patch this at run-time to change the behavior
* of bootp/dhcp.
*/
int bootp_flags;

static void
bootp_addvend(u_char *area)
{
#ifdef SUPPORT_DHCP
char vci[64];
int vcilen;

*area++ = TAG_PARAM_REQ;
*area++ = 6;
*area++ = TAG_SUBNET_MASK;
*area++ = TAG_GATEWAY;
*area++ = TAG_HOSTNAME;
*area++ = TAG_DOMAINNAME;
*area++ = TAG_ROOTPATH;
*area++ = TAG_SWAPSERVER;

/* Insert a NetBSD Vendor Class Identifier option. */
snprintf(vci, sizeof(vci), "NetBSD:%s:libsa", MACHINE);
vcilen = strlen(vci);
*area++ = TAG_CLASSID;
*area++ = vcilen;
(void)memcpy(area, vci, vcilen);
area += vcilen;
#endif
*area = TAG_END;
}

/* Fetch required bootp information */
void
bootp(int sock)
{
struct iodesc *d;
struct bootp *bp;
struct {
u_char header[UDP_TOTAL_HEADER_SIZE];
struct bootp wbootp;
} wbuf;
struct {
u_char header[UDP_TOTAL_HEADER_SIZE];
struct bootp rbootp;
} rbuf;
unsigned int index;

#ifdef BOOTP_DEBUG
if (debug)
printf("%s: socket=%d\n", __func__, sock);
#endif
if (!bot)
bot = getsecs();

if (!(d = socktodesc(sock))) {
printf("%s: bad socket. %d\n", __func__, sock);
return;
}
#ifdef BOOTP_DEBUG
if (debug)
printf("%s: d=%p\n", __func__, d);
#endif

bp = &wbuf.wbootp;
(void)memset(bp, 0, sizeof(*bp));

bp->bp_op = BOOTREQUEST;
bp->bp_htype = 1; /* 10Mb Ethernet (48 bits) */
bp->bp_hlen = 6;
bp->bp_xid = htonl(d->xid);
MACPY(d->myea, bp->bp_chaddr);
(void)strncpy((char *)bp->bp_file, bootfile, sizeof(bp->bp_file));
(void)memcpy(bp->bp_vend, vm_rfc1048, sizeof(vm_rfc1048));
index = 4;
#ifdef SUPPORT_DHCP
bp->bp_vend[index++] = TAG_DHCP_MSGTYPE;
bp->bp_vend[index++] = 1;
bp->bp_vend[index++] = DHCPDISCOVER;
#endif
bootp_addvend(&bp->bp_vend[index]);

d->myip.s_addr = INADDR_ANY;
d->myport = htons(IPPORT_BOOTPC);
d->destip.s_addr = INADDR_BROADCAST;
d->destport = htons(IPPORT_BOOTPS);

#ifdef SUPPORT_DHCP
expected_dhcpmsgtype = DHCPOFFER;
dhcp_ok = 0;
#endif

if (sendrecv(d, bootpsend, bp, sizeof(*bp),
bootprecv, &rbuf.rbootp, sizeof(rbuf.rbootp)) == -1) {
printf("%s: no reply\n", __func__);
return;
}

#ifdef SUPPORT_DHCP
if (dhcp_ok) {
u_int32_t leasetime;
index = 6;
bp->bp_vend[index++] = DHCPREQUEST;
bp->bp_vend[index++] = TAG_REQ_ADDR;
bp->bp_vend[index++] = 4;
(void)memcpy(&bp->bp_vend[9], &rbuf.rbootp.bp_yiaddr, 4);
index += 4;
bp->bp_vend[index++] = TAG_SERVERID;
bp->bp_vend[index++] = 4;
(void)memcpy(&bp->bp_vend[index], &dhcp_serverip.s_addr, 4);
index += 4;
bp->bp_vend[index++] = TAG_LEASETIME;
bp->bp_vend[index++] = 4;
leasetime = htonl(300);
(void)memcpy(&bp->bp_vend[index], &leasetime, 4);
index += 4;
bootp_addvend(&bp->bp_vend[index]);

expected_dhcpmsgtype = DHCPACK;

if (sendrecv(d,
bootpsend, bp, sizeof(*bp),
bootprecv, &rbuf.rbootp, sizeof(rbuf.rbootp))
== -1) {
printf("DHCPREQUEST failed\n");
return;
}
}
#endif

myip = d->myip = rbuf.rbootp.bp_yiaddr;
servip = rbuf.rbootp.bp_siaddr;
if (rootip.s_addr == INADDR_ANY)
rootip = servip;
(void)memcpy(bootfile, rbuf.rbootp.bp_file, sizeof(bootfile));
bootfile[sizeof(bootfile) - 1] = '\0';

if (IN_CLASSA(myip.s_addr))
nmask = IN_CLASSA_NET;
else if (IN_CLASSB(myip.s_addr))
nmask = IN_CLASSB_NET;
else
nmask = IN_CLASSC_NET;
#ifdef BOOTP_DEBUG
if (debug)
printf("'native netmask' is %s\n", intoa(nmask));
#endif

/* Get subnet (or natural net) mask */
netmask = nmask;
if (smask)
netmask = smask;
#ifdef BOOTP_DEBUG
if (debug)
printf("mask: %s\n", intoa(netmask));
#endif

/* We need a gateway if root is on a different net */
if (!SAMENET(myip, rootip, netmask)) {
#ifdef BOOTP_DEBUG
if (debug)
printf("need gateway for root ip\n");
#endif
}

/* Toss gateway if on a different net */
if (!SAMENET(myip, gateip, netmask)) {
#ifdef BOOTP_DEBUG
if (debug)
printf("gateway ip (%s) bad\n", inet_ntoa(gateip));
#endif
gateip.s_addr = 0;
}

#ifdef BOOTP_DEBUG
if (debug) {
printf("client addr: %s\n", inet_ntoa(myip));
if (smask)
printf("subnet mask: %s\n", intoa(smask));
if (gateip.s_addr != 0)
printf("net gateway: %s\n", inet_ntoa(gateip));
printf("server addr: %s\n", inet_ntoa(rootip));
if (rootpath[0] != '\0')
printf("server path: %s\n", rootpath);
if (bootfile[0] != '\0')
printf("file name: %s\n", bootfile);
}
#endif

/* Bump xid so next request will be unique. */
++d->xid;
}

/* Transmit a bootp request */
static ssize_t
bootpsend(struct iodesc *d, void *pkt, size_t len)
{
struct bootp *bp;

#ifdef BOOTP_DEBUG
if (debug)
printf("%s: d=%p called.\n", __func__, d);
#endif

bp = pkt;
bp->bp_secs = htons((u_short)(getsecs() - bot));

#ifdef BOOTP_DEBUG
if (debug)
printf("%s: calling sendudp\n", __func__);
#endif

return sendudp(d, pkt, len);
}

static ssize_t
bootprecv(struct iodesc *d, void *pkt, size_t len, saseconds_t tleft)
{
ssize_t n;
struct bootp *bp;

#ifdef BOOTP_DEBUG
if (debug)
printf("%s: called\n", __func__);
#endif

n = readudp(d, pkt, len, tleft);
if (n == -1 || (size_t)n < sizeof(struct bootp) - BOOTP_VENDSIZE)
goto bad;

bp = (struct bootp *)pkt;

#ifdef BOOTP_DEBUG
if (debug)
printf("%s: checked. bp = %p, n = %zd\n", __func__, bp, n);
#endif
if (bp->bp_xid != htonl(d->xid)) {
#ifdef BOOTP_DEBUG
if (debug) {
printf("%s: expected xid 0x%lx, got 0x%x\n", __func__,
d->xid, ntohl(bp->bp_xid));
}
#endif
goto bad;
}

/* protect against bogus addresses sent by DHCP servers */
if (bp->bp_yiaddr.s_addr == INADDR_ANY ||
bp->bp_yiaddr.s_addr == INADDR_BROADCAST)
goto bad;

#ifdef BOOTP_DEBUG
if (debug)
printf("%s: got one!\n", __func__);
#endif

/* Suck out vendor info */
if (memcmp(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048)) == 0) {
if (vend_rfc1048(bp->bp_vend, sizeof(bp->bp_vend)) != 0)
goto bad;
}
#ifdef BOOTP_VEND_CMU
else if (memcmp(vm_cmu, bp->bp_vend, sizeof(vm_cmu)) == 0)
vend_cmu(bp->bp_vend);
#endif
else
printf("%s: unknown vendor %p\n", __func__, bp->bp_vend);

return n;
bad:
errno = 0;
return -1;
}

static int
vend_rfc1048(u_char *cp, u_int len)
{
u_char *ep;
size_t size;
u_char tag;

#ifdef BOOTP_DEBUG
if (debug)
printf("%s: bootp info. len=%d\n", __func__, len);
#endif
ep = cp + len;

/* Step over magic cookie */
cp += sizeof(int);

while (cp < ep) {
tag = *cp++;
size = *cp++;
if (tag == TAG_END)
break;

if (tag == TAG_SUBNET_MASK && size >= sizeof(smask)) {
(void)memcpy(&smask, cp, sizeof(smask));
}
if (tag == TAG_GATEWAY && size >= sizeof(gateip.s_addr)) {
(void)memcpy(&gateip.s_addr, cp, sizeof(gateip.s_addr));
}
if (tag == TAG_SWAPSERVER && size >= sizeof(rootip.s_addr)) {
/* let it override bp_siaddr */
(void)memcpy(&rootip.s_addr, cp, sizeof(rootip.s_addr));
}
if (tag == TAG_ROOTPATH && size < sizeof(rootpath)) {
strncpy(rootpath, (char *)cp, sizeof(rootpath));
rootpath[size] = '\0';
}
if (tag == TAG_HOSTNAME && size < sizeof(hostname)) {
strncpy(hostname, (char *)cp, sizeof(hostname));
hostname[size] = '\0';
}
#ifdef SUPPORT_DHCP
if (tag == TAG_DHCP_MSGTYPE) {
if (*cp != expected_dhcpmsgtype)
return -1;
dhcp_ok = 1;
}
if (tag == TAG_SERVERID &&
size >= sizeof(dhcp_serverip.s_addr))
{
(void)memcpy(&dhcp_serverip.s_addr, cp,
sizeof(dhcp_serverip.s_addr));
}
#endif
#ifdef SUPPORT_LINUX
if (tag == TAG_LINUX_CMDLINE && size < sizeof(linuxcmdline)) {
strncpy(linuxcmdline, (char *)cp, sizeof(linuxcmdline));
linuxcmdline[size] = '\0';
}
#endif
cp += size;
}
return 0;
}

#ifdef BOOTP_VEND_CMU
static void
vend_cmu(u_char *cp)
{
struct cmu_vend *vp;

#ifdef BOOTP_DEBUG
if (debug)
printf("%s: bootp info.\n", __func__);
#endif
vp = (struct cmu_vend *)cp;

if (vp->v_smask.s_addr != 0) {
smask = vp->v_smask.s_addr;
}
if (vp->v_dgate.s_addr != 0) {
gateip = vp->v_dgate;
}
}
#endif