/*      $NetBSD: svc_dg.c,v 1.18 2024/01/23 17:24:38 christos Exp $     */

/*
* Copyright (c) 2010, Oracle America, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
*     * Redistributions of source code must retain the above copyright
*       notice, this list of conditions and the following disclaimer.
*     * 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.
*     * Neither the name of the "Oracle America, Inc." 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 COPYRIGHT HOLDERS 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
*   COPYRIGHT HOLDER 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.
*/

/*
* Copyright (c) 1986-1991 by Sun Microsystems Inc.
*/

/* #ident       "@(#)svc_dg.c   1.17    94/04/24 SMI" */


/*
* svc_dg.c, Server side for connectionless RPC.
*
* Does some caching in the hopes of achieving execute-at-most-once semantics.
*/

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: svc_dg.c,v 1.18 2024/01/23 17:24:38 christos Exp $");
#endif

#include "namespace.h"
#include "reentrant.h"
#include <sys/types.h>
#include <sys/socket.h>
#include <rpc/rpc.h>
#include <assert.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef RPC_CACHE_DEBUG
#include <netconfig.h>
#include <netdir.h>
#endif
#include <err.h>

#include "svc_fdset.h"
#include "rpc_internal.h"
#include "svc_dg.h"

#define su_data(xprt)   ((struct svc_dg_data *)(xprt->xp_p2))
#define rpc_buffer(xprt) ((xprt)->xp_p1)

#ifdef __weak_alias
__weak_alias(svc_dg_create,_svc_dg_create)
#endif

#ifndef MAX
#define MAX(a, b)       (((a) > (b)) ? (a) : (b))
#endif

static void svc_dg_ops(SVCXPRT *);
static enum xprt_stat svc_dg_stat(SVCXPRT *);
static bool_t svc_dg_recv(SVCXPRT *, struct rpc_msg *);
static bool_t svc_dg_reply(SVCXPRT *, struct rpc_msg *);
static bool_t svc_dg_getargs(SVCXPRT *, xdrproc_t, caddr_t);
static bool_t svc_dg_freeargs(SVCXPRT *, xdrproc_t, caddr_t);
static void svc_dg_destroy(SVCXPRT *);
static bool_t svc_dg_control(SVCXPRT *, const u_int, void *);
static int cache_get(SVCXPRT *, struct rpc_msg *, char **, size_t *);
static void cache_set(SVCXPRT *, size_t);

/*
* Usage:
*      xprt = svc_dg_create(sock, sendsize, recvsize);
* Does other connectionless specific initializations.
* Once *xprt is initialized, it is registered.
* see (svc.h, xprt_register). If recvsize or sendsize are 0 suitable
* system defaults are chosen.
* The routines returns NULL if a problem occurred.
*/
static const char svc_dg_str[] = "svc_dg_create: %s";
static const char svc_dg_err1[] = "could not get transport information";
static const char svc_dg_err2[] = " transport does not support data transfer";
static const char __no_mem_str[] = "out of memory";

SVCXPRT *
svc_dg_create(int fd, u_int sendsize, u_int recvsize)
{
       SVCXPRT *xprt;
       struct svc_dg_data *su = NULL;
       struct __rpc_sockinfo si;
       struct sockaddr_storage ss;
       socklen_t slen;

       if (!__rpc_fd2sockinfo(fd, &si)) {
               warnx(svc_dg_str, svc_dg_err1);
               return (NULL);
       }
       /*
        * Find the receive and the send size
        */
       sendsize = __rpc_get_t_size(si.si_af, si.si_proto, (int)sendsize);
       recvsize = __rpc_get_t_size(si.si_af, si.si_proto, (int)recvsize);
       if ((sendsize == 0) || (recvsize == 0)) {
               warnx(svc_dg_str, svc_dg_err2);
               return (NULL);
       }

       xprt = mem_alloc(sizeof (SVCXPRT));
       if (xprt == NULL)
               goto outofmem;
       memset(xprt, 0, sizeof (SVCXPRT));

       su = mem_alloc(sizeof (*su));
       if (su == NULL)
               goto outofmem;
       su->su_iosz = ((MAX(sendsize, recvsize) + 3) / 4) * 4;
       if ((rpc_buffer(xprt) = malloc(su->su_iosz)) == NULL)
               goto outofmem;
       _DIAGASSERT(__type_fit(u_int, su->su_iosz));
       xdrmem_create(&(su->su_xdrs), rpc_buffer(xprt), (u_int)su->su_iosz,
               XDR_DECODE);
       su->su_cache = NULL;
       xprt->xp_fd = fd;
       xprt->xp_p2 = (caddr_t)(void *)su;
       xprt->xp_verf.oa_base = su->su_verfbody;
       svc_dg_ops(xprt);
       xprt->xp_rtaddr.maxlen = sizeof (struct sockaddr_storage);

       slen = sizeof ss;
       if (getsockname(fd, (struct sockaddr *)(void *)&ss, &slen) < 0)
               goto freedata;
       xprt->xp_ltaddr.buf = mem_alloc(sizeof (struct sockaddr_storage));
       xprt->xp_ltaddr.maxlen = sizeof (struct sockaddr_storage);
       xprt->xp_ltaddr.len = slen;
       memcpy(xprt->xp_ltaddr.buf, &ss, slen);

       if (!xprt_register(xprt))
               goto freedata;
       return (xprt);

outofmem:
       (void) warnx(svc_dg_str, __no_mem_str);
freedata:
       if (xprt) {
               if (su)
                       (void) mem_free(su, sizeof (*su));
               (void) mem_free(xprt, sizeof (SVCXPRT));
       }
       return (NULL);
}

/*ARGSUSED*/
static enum xprt_stat
svc_dg_stat(SVCXPRT *xprt)
{
       return (XPRT_IDLE);
}

static bool_t
svc_dg_recv(SVCXPRT *xprt, struct rpc_msg *msg)
{
       struct svc_dg_data *su;
       XDR *xdrs;
       char *reply;
       struct sockaddr_storage ss;
       socklen_t alen;
       size_t replylen;
       ssize_t rlen;

       _DIAGASSERT(xprt != NULL);
       _DIAGASSERT(msg != NULL);

       su = su_data(xprt);
       xdrs = &(su->su_xdrs);

again:
       alen = sizeof (struct sockaddr_storage);
       rlen = recvfrom(xprt->xp_fd, rpc_buffer(xprt), su->su_iosz, 0,
           (struct sockaddr *)(void *)&ss, &alen);
       if (rlen == -1 && errno == EINTR)
               goto again;
       if (rlen == -1 || (rlen < (ssize_t)(4 * sizeof (u_int32_t))))
               return (FALSE);
       if (xprt->xp_rtaddr.len < alen) {
               if (xprt->xp_rtaddr.len != 0)
                       mem_free(xprt->xp_rtaddr.buf, xprt->xp_rtaddr.len);
               xprt->xp_rtaddr.buf = mem_alloc(alen);
               xprt->xp_rtaddr.len = alen;
       }
       memcpy(xprt->xp_rtaddr.buf, &ss, alen);
#ifdef PORTMAP
       if (ss.ss_family == AF_INET) {
               xprt->xp_raddr = *(struct sockaddr_in *)xprt->xp_rtaddr.buf;
               xprt->xp_addrlen = sizeof (struct sockaddr_in);
       }
#endif
       xdrs->x_op = XDR_DECODE;
       XDR_SETPOS(xdrs, 0);
       if (! xdr_callmsg(xdrs, msg)) {
               return (FALSE);
       }
       su->su_xid = msg->rm_xid;
       if (su->su_cache != NULL) {
               if (cache_get(xprt, msg, &reply, &replylen)) {
                       (void)sendto(xprt->xp_fd, reply, replylen, 0,
                           (struct sockaddr *)(void *)&ss, alen);
                       return (FALSE);
               }
       }
       return (TRUE);
}

static bool_t
svc_dg_reply(SVCXPRT *xprt, struct rpc_msg *msg)
{
       struct svc_dg_data *su;
       XDR *xdrs;
       bool_t stat = FALSE;
       size_t slen;

       _DIAGASSERT(xprt != NULL);
       _DIAGASSERT(msg != NULL);

       su = su_data(xprt);
       xdrs = &(su->su_xdrs);

       xdrs->x_op = XDR_ENCODE;
       XDR_SETPOS(xdrs, 0);
       msg->rm_xid = su->su_xid;
       if (xdr_replymsg(xdrs, msg)) {
               slen = XDR_GETPOS(xdrs);
               if (sendto(xprt->xp_fd, rpc_buffer(xprt), slen, 0,
                   (struct sockaddr *)xprt->xp_rtaddr.buf,
                   (socklen_t)xprt->xp_rtaddr.len) == (ssize_t) slen) {
                       stat = TRUE;
                       if (su->su_cache)
                               cache_set(xprt, slen);
               }
       }
       return (stat);
}

static bool_t
svc_dg_getargs(SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)
{
       return (*xdr_args)(&(su_data(xprt)->su_xdrs), args_ptr);
}

static bool_t
svc_dg_freeargs(SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)
{
       XDR *xdrs;

       _DIAGASSERT(xprt != NULL);

       xdrs = &(su_data(xprt)->su_xdrs);
       xdrs->x_op = XDR_FREE;
       return (*xdr_args)(xdrs, args_ptr);
}

static void
svc_dg_destroy(SVCXPRT *xprt)
{
       struct svc_dg_data *su;

       _DIAGASSERT(xprt != NULL);

       su = su_data(xprt);

       xprt_unregister(xprt);
       if (xprt->xp_fd != -1)
               (void)close(xprt->xp_fd);
       XDR_DESTROY(&(su->su_xdrs));
       (void) mem_free(rpc_buffer(xprt), su->su_iosz);
       (void) mem_free(su, sizeof (*su));
       if (xprt->xp_rtaddr.buf)
               (void) mem_free(xprt->xp_rtaddr.buf, xprt->xp_rtaddr.maxlen);
       if (xprt->xp_ltaddr.buf)
               (void) mem_free(xprt->xp_ltaddr.buf, xprt->xp_ltaddr.maxlen);
       if (xprt->xp_tp)
               (void) free(xprt->xp_tp);
       (void) mem_free(xprt, sizeof (SVCXPRT));
}

static bool_t
/*ARGSUSED*/
svc_dg_control(SVCXPRT *xprt, const u_int rq, void *in)
{
       return (FALSE);
}

static void
svc_dg_ops(SVCXPRT *xprt)
{
       static struct xp_ops ops;
       static struct xp_ops2 ops2;

       _DIAGASSERT(xprt != NULL);

/* VARIABLES PROTECTED BY ops_lock: ops */

       mutex_lock(&ops_lock);
       if (ops.xp_recv == NULL) {
               ops.xp_recv = svc_dg_recv;
               ops.xp_stat = svc_dg_stat;
               ops.xp_getargs = svc_dg_getargs;
               ops.xp_reply = svc_dg_reply;
               ops.xp_freeargs = svc_dg_freeargs;
               ops.xp_destroy = svc_dg_destroy;
               ops2.xp_control = svc_dg_control;
       }
       xprt->xp_ops = &ops;
       xprt->xp_ops2 = &ops2;
       mutex_unlock(&ops_lock);
}

/*  The CACHING COMPONENT */

/*
* Could have been a separate file, but some part of it depends upon the
* private structure of the client handle.
*
* Fifo cache for cl server
* Copies pointers to reply buffers into fifo cache
* Buffers are sent again if retransmissions are detected.
*/

#define SPARSENESS 4    /* 75% sparse */

#define ALLOC(type, size)       \
       mem_alloc((sizeof (type) * (size)))

#define MEMZERO(addr, type, size)        \
       (void) memset((void *) (addr), 0, sizeof (type) * (int) (size))

#define FREE(addr, type, size)  \
       mem_free((addr), (sizeof (type) * (size)))

/*
* An entry in the cache
*/
typedef struct cache_node *cache_ptr;
struct cache_node {
       /*
        * Index into cache is xid, proc, vers, prog and address
        */
       u_int32_t cache_xid;
       rpcproc_t cache_proc;
       rpcvers_t cache_vers;
       rpcprog_t cache_prog;
       struct netbuf cache_addr;
       /*
        * The cached reply and length
        */
       char *cache_reply;
       size_t cache_replylen;
       /*
        * Next node on the list, if there is a collision
        */
       cache_ptr cache_next;
};

/*
* The entire cache
*/
struct cl_cache {
       u_int uc_size;          /* size of cache */
       cache_ptr *uc_entries;  /* hash table of entries in cache */
       cache_ptr *uc_fifo;     /* fifo list of entries in cache */
       u_int uc_nextvictim;    /* points to next victim in fifo list */
       rpcprog_t uc_prog;      /* saved program number */
       rpcvers_t uc_vers;      /* saved version number */
       rpcproc_t uc_proc;      /* saved procedure number */
};


/*
* the hashing function
*/
#define CACHE_LOC(transp, xid)  \
       (xid % (SPARSENESS * ((struct cl_cache *) \
               su_data(transp)->su_cache)->uc_size))

/*
* Enable use of the cache. Returns 1 on success, 0 on failure.
* Note: there is no disable.
*/
static const char cache_enable_str[] = "svc_enablecache: %s %s";
static const char alloc_err[] = "could not allocate cache ";
static const char enable_err[] = "cache already enabled";

int
svc_dg_enablecache(SVCXPRT *transp, u_int size)
{
       struct svc_dg_data *su;
       struct cl_cache *uc;

       _DIAGASSERT(transp != NULL);

       su = su_data(transp);

       mutex_lock(&dupreq_lock);
       if (su->su_cache != NULL) {
               (void) warnx(cache_enable_str, enable_err, " ");
               mutex_unlock(&dupreq_lock);
               return (0);
       }
       uc = ALLOC(struct cl_cache, 1);
       if (uc == NULL) {
               warnx(cache_enable_str, alloc_err, " ");
               mutex_unlock(&dupreq_lock);
               return (0);
       }
       uc->uc_size = size;
       uc->uc_nextvictim = 0;
       uc->uc_entries = ALLOC(cache_ptr, size * SPARSENESS);
       if (uc->uc_entries == NULL) {
               warnx(cache_enable_str, alloc_err, "data");
               FREE(uc, struct cl_cache, 1);
               mutex_unlock(&dupreq_lock);
               return (0);
       }
       MEMZERO(uc->uc_entries, cache_ptr, size * SPARSENESS);
       uc->uc_fifo = ALLOC(cache_ptr, size);
       if (uc->uc_fifo == NULL) {
               warnx(cache_enable_str, alloc_err, "fifo");
               FREE(uc->uc_entries, cache_ptr, size * SPARSENESS);
               FREE(uc, struct cl_cache, 1);
               mutex_unlock(&dupreq_lock);
               return (0);
       }
       MEMZERO(uc->uc_fifo, cache_ptr, size);
       su->su_cache = (char *)(void *)uc;
       mutex_unlock(&dupreq_lock);
       return (1);
}

/*
* Set an entry in the cache.  It assumes that the uc entry is set from
* the earlier call to cache_get() for the same procedure.  This will always
* happen because cache_get() is calle by svc_dg_recv and cache_set() is called
* by svc_dg_reply().  All this hoopla because the right RPC parameters are
* not available at svc_dg_reply time.
*/

static const char cache_set_str[] = "cache_set: %s";
static const char cache_set_err1[] = "victim not found";
static const char cache_set_err2[] = "victim alloc failed";
static const char cache_set_err3[] = "could not allocate new rpc buffer";

static void
cache_set(SVCXPRT *xprt, size_t replylen)
{
       cache_ptr victim;
       cache_ptr *vicp;
       struct svc_dg_data *su;
       struct cl_cache *uc;
       u_int loc;
       char *newbuf;
#ifdef RPC_CACHE_DEBUG
       struct netconfig *nconf;
       char *uaddr;
#endif

       _DIAGASSERT(xprt != NULL);

       su = su_data(xprt);
       uc = (struct cl_cache *) su->su_cache;

       mutex_lock(&dupreq_lock);
       /*
        * Find space for the new entry, either by
        * reusing an old entry, or by mallocing a new one
        */
       victim = uc->uc_fifo[uc->uc_nextvictim];
       if (victim != NULL) {
               loc = CACHE_LOC(xprt, victim->cache_xid);
               for (vicp = &uc->uc_entries[loc];
                       *vicp != NULL && *vicp != victim;
                       vicp = &(*vicp)->cache_next)
                       ;
               if (*vicp == NULL) {
                       warnx(cache_set_str, cache_set_err1);
                       mutex_unlock(&dupreq_lock);
                       return;
               }
               *vicp = victim->cache_next;     /* remove from cache */
               newbuf = victim->cache_reply;
       } else {
               victim = ALLOC(struct cache_node, 1);
               if (victim == NULL) {
                       warnx(cache_set_str, cache_set_err2);
                       mutex_unlock(&dupreq_lock);
                       return;
               }
               newbuf = mem_alloc(su->su_iosz);
               if (newbuf == NULL) {
                       warnx(cache_set_str, cache_set_err3);
                       FREE(victim, struct cache_node, 1);
                       mutex_unlock(&dupreq_lock);
                       return;
               }
       }

       /*
        * Store it away
        */
#ifdef RPC_CACHE_DEBUG
       if (nconf = getnetconfigent(xprt->xp_netid)) {
               uaddr = taddr2uaddr(nconf, &xprt->xp_rtaddr);
               freenetconfigent(nconf);
               printf(
       "cache set for xid= %x prog=%d vers=%d proc=%d for rmtaddr=%s\n",
                       su->su_xid, uc->uc_prog, uc->uc_vers,
                       uc->uc_proc, uaddr);
               free(uaddr);
       }
#endif
       victim->cache_replylen = replylen;
       victim->cache_reply = rpc_buffer(xprt);
       rpc_buffer(xprt) = newbuf;
       _DIAGASSERT(__type_fit(u_int, su->su_iosz));
       xdrmem_create(&(su->su_xdrs), rpc_buffer(xprt), (u_int)su->su_iosz,
           XDR_ENCODE);
       victim->cache_xid = su->su_xid;
       victim->cache_proc = uc->uc_proc;
       victim->cache_vers = uc->uc_vers;
       victim->cache_prog = uc->uc_prog;
       victim->cache_addr = xprt->xp_rtaddr;
       victim->cache_addr.buf = ALLOC(char, xprt->xp_rtaddr.len);
       (void) memcpy(victim->cache_addr.buf, xprt->xp_rtaddr.buf,
           (size_t)xprt->xp_rtaddr.len);
       loc = CACHE_LOC(xprt, victim->cache_xid);
       victim->cache_next = uc->uc_entries[loc];
       uc->uc_entries[loc] = victim;
       uc->uc_fifo[uc->uc_nextvictim++] = victim;
       uc->uc_nextvictim %= uc->uc_size;
       mutex_unlock(&dupreq_lock);
}

/*
* Try to get an entry from the cache
* return 1 if found, 0 if not found and set the stage for cache_set()
*/
static int
cache_get(SVCXPRT *xprt, struct rpc_msg *msg, char **replyp, size_t *replylenp)
{
       u_int loc;
       cache_ptr ent;
       struct svc_dg_data *su;
       struct cl_cache *uc;
#ifdef RPC_CACHE_DEBUG
       struct netconfig *nconf;
       char *uaddr;
#endif

       _DIAGASSERT(xprt != NULL);
       _DIAGASSERT(msg != NULL);
       _DIAGASSERT(replyp != NULL);
       _DIAGASSERT(replylenp != NULL);

       su = su_data(xprt);
       uc = (struct cl_cache *) su->su_cache;

       mutex_lock(&dupreq_lock);
       loc = CACHE_LOC(xprt, su->su_xid);
       for (ent = uc->uc_entries[loc]; ent != NULL; ent = ent->cache_next) {
               if (ent->cache_xid == su->su_xid &&
                       ent->cache_proc == msg->rm_call.cb_proc &&
                       ent->cache_vers == msg->rm_call.cb_vers &&
                       ent->cache_prog == msg->rm_call.cb_prog &&
                       ent->cache_addr.len == xprt->xp_rtaddr.len &&
                       (memcmp(ent->cache_addr.buf, xprt->xp_rtaddr.buf,
                               xprt->xp_rtaddr.len) == 0)) {
#ifdef RPC_CACHE_DEBUG
                       if (nconf = getnetconfigent(xprt->xp_netid)) {
                               uaddr = taddr2uaddr(nconf, &xprt->xp_rtaddr);
                               freenetconfigent(nconf);
                               printf(
       "cache entry found for xid=%x prog=%d vers=%d proc=%d for rmtaddr=%s\n",
                                       su->su_xid, msg->rm_call.cb_prog,
                                       msg->rm_call.cb_vers,
                                       msg->rm_call.cb_proc, uaddr);
                               free(uaddr);
                       }
#endif
                       *replyp = ent->cache_reply;
                       *replylenp = ent->cache_replylen;
                       mutex_unlock(&dupreq_lock);
                       return (1);
               }
       }
       /*
        * Failed to find entry
        * Remember a few things so we can do a set later
        */
       uc->uc_proc = msg->rm_call.cb_proc;
       uc->uc_vers = msg->rm_call.cb_vers;
       uc->uc_prog = msg->rm_call.cb_prog;
       mutex_unlock(&dupreq_lock);
       return (0);
}

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