svc_dg.c

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/*
 * Copyright (c) 2009, Sun Microsystems, Inc.
 * All rights reserved.
 *
 * 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 Sun Microsystems, 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.
 */
 
//#include <sys/cdefs.h>
 
/*
 * svc_dg.c, Server side for connectionless RPC.
 *
 * Does some caching in the hopes of achieving execute-at-most-once semantics.
 */
#include <wintirpc.h>
//#include <pthread.h>
#include <reentrant.h>
#include <sys/types.h>
//#include <sys/socket.h>
#include <rpc/rpc.h>
#include <rpc/svc_dg.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 "rpc_com.h"
 
#define su_data(xprt)   ((struct svc_dg_data *)(xprt->xp_p2))
#define rpc_buffer(xprt) ((xprt)->xp_p1)
 
#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, void *);
static bool_t svc_dg_freeargs(SVCXPRT *, xdrproc_t, void *);
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);
int svc_dg_enablecache(SVCXPRT *, u_int);
 
/*
 * 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(fd, sendsize, recvsize)
    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)) {
        // XXX 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)) {
        // XXX warnx(svc_dg_str, svc_dg_err2);
        return (NULL);
    }
 
    xprt = mem_alloc(sizeof (SVCXPRT));
    if (xprt == NULL)
        goto freedata;
    memset(xprt, 0, sizeof (SVCXPRT));
 
    su = mem_alloc(sizeof (*su));
    if (su == NULL)
        goto freedata;
    su->su_iosz = ((MAX(sendsize, recvsize) + 3) / 4) * 4;
    if ((rpc_buffer(xprt) = mem_alloc(su->su_iosz)) == NULL)
        goto freedata;
    xdrmem_create(&(su->su_xdrs), rpc_buffer(xprt), su->su_iosz,
        XDR_DECODE);
    su->su_cache = NULL;
    xprt->xp_fd = fd;
    xprt->xp_p2 = 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) == SOCKET_ERROR)
        goto freedata;
    __rpc_set_netbuf(&xprt->xp_ltaddr, &ss, slen);
 
    xprt_register(xprt);
    return (xprt);
freedata:
    // XXX (void) warnx(svc_dg_str, __no_mem_str);
    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(xprt)
    SVCXPRT *xprt;
{
    return (XPRT_IDLE);
}
 
static bool_t
svc_dg_recv(xprt, msg)
    SVCXPRT *xprt;
    struct rpc_msg *msg;
{
    struct svc_dg_data *su = su_data(xprt);
    XDR *xdrs = &(su->su_xdrs);
    char *reply;
    struct sockaddr_storage ss;
    socklen_t alen;
    size_t replylen;
    ssize_t rlen;
 
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);
    __rpc_set_netbuf(&xprt->xp_rtaddr, &ss, alen);
 
    __xprt_set_raddr(xprt, &ss);
    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(xprt, msg)
    SVCXPRT *xprt;
    struct rpc_msg *msg;
{
    struct svc_dg_data *su = su_data(xprt);
    XDR *xdrs = &(su->su_xdrs);
    bool_t stat = FALSE;
    size_t slen;
 
    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(xprt, xdr_args, args_ptr)
    SVCXPRT *xprt;
    xdrproc_t xdr_args;
    void *args_ptr;
{
    return (*xdr_args)(&(su_data(xprt)->su_xdrs), args_ptr);
}
 
static bool_t
svc_dg_freeargs(xprt, xdr_args, args_ptr)
    SVCXPRT *xprt;
    xdrproc_t xdr_args;
    void *args_ptr;
{
    XDR *xdrs = &(su_data(xprt)->su_xdrs);
 
    xdrs->x_op = XDR_FREE;
    return (*xdr_args)(xdrs, args_ptr);
}
 
static void
svc_dg_destroy(xprt)
    SVCXPRT *xprt;
{
    struct svc_dg_data *su = su_data(xprt);
 
    xprt_unregister(xprt);
    if (xprt->xp_fd != -1)
        (void)closesocket(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(xprt, rq, in)
    SVCXPRT *xprt;
    const u_int rq;
    void        *in;
{
    return (FALSE);
}
 
static void
svc_dg_ops(xprt)
    SVCXPRT *xprt;
{
    static struct xp_ops ops;
    static struct xp_ops2 ops2;
    extern mutex_t ops_lock;
 
/* 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)   \
    (type *) 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))
 
extern mutex_t  dupreq_lock;
 
/*
 * 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(transp, size)
    SVCXPRT *transp;
    u_int size;
{
    struct svc_dg_data *su = su_data(transp);
    struct cl_cache *uc;
 
    mutex_lock(&dupreq_lock);
    if (su->su_cache != NULL) {
        // XXX (void) warnx(cache_enable_str, enable_err, " ");
        mutex_unlock(&dupreq_lock);
        return (0);
    }
    uc = ALLOC(struct cl_cache, 1);
    if (uc == NULL) {
        // XXX 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) {
        // XXX 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) {
        // XXX 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(xprt, replylen)
    SVCXPRT *xprt;
    size_t replylen;
{
    cache_ptr victim;
    cache_ptr *vicp;
    struct svc_dg_data *su = su_data(xprt);
    struct cl_cache *uc = (struct cl_cache *) su->su_cache;
    u_int loc;
    char *newbuf;
#ifdef RPC_CACHE_DEBUG
    struct netconfig *nconf;
    char *uaddr;
#endif
 
    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) {
            // XXX 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) {
            // XXX warnx(cache_set_str, cache_set_err2);
            mutex_unlock(&dupreq_lock);
            return;
        }
        newbuf = mem_alloc(su->su_iosz);
        if (newbuf == NULL) {
            // XXX 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;
    xdrmem_create(&(su->su_xdrs), rpc_buffer(xprt),
            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(xprt, msg, replyp, replylenp)
    SVCXPRT *xprt;
    struct rpc_msg *msg;
    char **replyp;
    size_t *replylenp;
{
    u_int loc;
    cache_ptr ent;
    struct svc_dg_data *su = su_data(xprt);
    struct cl_cache *uc = (struct cl_cache *) su->su_cache;
#ifdef RPC_CACHE_DEBUG
    struct netconfig *nconf;
    char *uaddr;
#endif
 
    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);
}