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glibc/sunrpc/svc_udp.c

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/*
* svc_udp.c,
* Server side for UDP/IP based RPC. (Does some caching in the hopes of
* achieving execute-at-most-once semantics.)
*
* Copyright (C) 2012-2024 Free Software Foundation, Inc.
* This file is part of the GNU C Library.
*
* The GNU C Library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* The GNU C Library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with the GNU C Library; if not, see
* <https://www.gnu.org/licenses/>.
*
* 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.
*/
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <rpc/rpc.h>
#include <sys/socket.h>
#include <errno.h>
#include <libintl.h>
#ifdef IP_PKTINFO
#include <sys/uio.h>
#endif
#include <wchar.h>
#include <libio/iolibio.h>
#include <shlib-compat.h>
#define rpc_buffer(xprt) ((xprt)->xp_p1)
#ifndef MAX
#define MAX(a, b) ((a > b) ? a : b)
#endif
static bool_t svcudp_recv (SVCXPRT *, struct rpc_msg *);
static bool_t svcudp_reply (SVCXPRT *, struct rpc_msg *);
static enum xprt_stat svcudp_stat (SVCXPRT *);
static bool_t svcudp_getargs (SVCXPRT *, xdrproc_t, caddr_t);
static bool_t svcudp_freeargs (SVCXPRT *, xdrproc_t, caddr_t);
static void svcudp_destroy (SVCXPRT *);
static const struct xp_ops svcudp_op =
{
svcudp_recv,
svcudp_stat,
svcudp_getargs,
svcudp_reply,
svcudp_freeargs,
svcudp_destroy
};
static int cache_get (SVCXPRT *, struct rpc_msg *, char **replyp,
u_long *replylenp);
static void cache_set (SVCXPRT *xprt, u_long replylen);
/*
* kept in xprt->xp_p2
*/
struct svcudp_data
{
u_int su_iosz; /* byte size of send.recv buffer */
u_long su_xid; /* transaction id */
XDR su_xdrs; /* XDR handle */
char su_verfbody[MAX_AUTH_BYTES]; /* verifier body */
char *su_cache; /* cached data, NULL if no cache */
};
#define su_data(xprt) ((struct svcudp_data *)(xprt->xp_p2))
/*
* Usage:
* xprt = svcudp_create(sock);
*
* If sock<0 then a socket is created, else sock is used.
* If the socket, sock is not bound to a port then svcudp_create
* binds it to an arbitrary port. In any (successful) case,
* xprt->xp_sock is the registered socket number and xprt->xp_port is the
* associated port number.
* Once *xprt is initialized, it is registered as a transporter;
* see (svc.h, xprt_register).
* The routines returns NULL if a problem occurred.
*/
SVCXPRT *
svcudp_bufcreate (int sock, u_int sendsz, u_int recvsz)
{
bool_t madesock = FALSE;
SVCXPRT *xprt;
struct svcudp_data *su;
struct sockaddr_in addr;
socklen_t len = sizeof (struct sockaddr_in);
int pad;
void *buf;
if (sock == RPC_ANYSOCK)
{
if ((sock = __socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
{
perror (_("svcudp_create: socket creation problem"));
return (SVCXPRT *) NULL;
}
madesock = TRUE;
}
memset ((char *) &addr, 0, sizeof (addr));
addr.sin_family = AF_INET;
if (bindresvport (sock, &addr))
{
addr.sin_port = 0;
(void) __bind (sock, (struct sockaddr *) &addr, len);
}
if (__getsockname (sock, (struct sockaddr *) &addr, &len) != 0)
{
perror (_("svcudp_create - cannot getsockname"));
if (madesock)
(void) __close (sock);
return (SVCXPRT *) NULL;
}
xprt = (SVCXPRT *) mem_alloc (sizeof (SVCXPRT));
su = (struct svcudp_data *) mem_alloc (sizeof (*su));
buf = mem_alloc (((MAX (sendsz, recvsz) + 3) / 4) * 4);
if (xprt == NULL || su == NULL || buf == NULL)
{
(void) __fxprintf (NULL, "%s: %s",
"svcudp_create", _("out of memory\n"));
mem_free (xprt, sizeof (SVCXPRT));
mem_free (su, sizeof (*su));
mem_free (buf, ((MAX (sendsz, recvsz) + 3) / 4) * 4);
return NULL;
}
su->su_iosz = ((MAX (sendsz, recvsz) + 3) / 4) * 4;
rpc_buffer (xprt) = buf;
xdrmem_create (&(su->su_xdrs), rpc_buffer (xprt), su->su_iosz, XDR_DECODE);
su->su_cache = NULL;
xprt->xp_p2 = (caddr_t) su;
xprt->xp_verf.oa_base = su->su_verfbody;
xprt->xp_ops = &svcudp_op;
xprt->xp_port = ntohs (addr.sin_port);
xprt->xp_sock = sock;
#ifdef IP_PKTINFO
if ((sizeof (struct iovec) + sizeof (struct msghdr)
+ sizeof(struct cmsghdr) + sizeof (struct in_pktinfo))
> sizeof (xprt->xp_pad))
{
(void) __fxprintf (NULL,"%s", _("\
svcudp_create: xp_pad is too small for IP_PKTINFO\n"));
return NULL;
}
pad = 1;
if (__setsockopt (sock, SOL_IP, IP_PKTINFO, (void *) &pad,
sizeof (pad)) == 0)
/* Set the padding to all 1s. */
pad = 0xff;
else
#endif
/* Clear the padding. */
pad = 0;
memset (&xprt->xp_pad [0], pad, sizeof (xprt->xp_pad));
xprt_register (xprt);
return xprt;
}
#ifdef EXPORT_RPC_SYMBOLS
libc_hidden_def (svcudp_bufcreate)
#else
libc_hidden_nolink_sunrpc (svcudp_bufcreate, GLIBC_2_0)
#endif
SVCXPRT *
svcudp_create (int sock)
{
return svcudp_bufcreate (sock, UDPMSGSIZE, UDPMSGSIZE);
}
#ifdef EXPORT_RPC_SYMBOLS
libc_hidden_def (svcudp_create)
#else
libc_hidden_nolink_sunrpc (svcudp_create, GLIBC_2_0)
#endif
static enum xprt_stat
svcudp_stat (SVCXPRT *xprt)
{
return XPRT_IDLE;
}
static bool_t
svcudp_recv (SVCXPRT *xprt, struct rpc_msg *msg)
{
struct svcudp_data *su = su_data (xprt);
XDR *xdrs = &(su->su_xdrs);
int rlen;
char *reply;
u_long replylen;
socklen_t len;
/* It is very tricky when you have IP aliases. We want to make sure
that we are sending the packet from the IP address where the
incoming packet is addressed to. H.J. */
#ifdef IP_PKTINFO
struct iovec *iovp;
struct msghdr *mesgp;
#endif
again:
/* FIXME -- should xp_addrlen be a size_t? */
len = (socklen_t) sizeof(struct sockaddr_in);
#ifdef IP_PKTINFO
iovp = (struct iovec *) &xprt->xp_pad [0];
mesgp = (struct msghdr *) &xprt->xp_pad [sizeof (struct iovec)];
if (mesgp->msg_iovlen)
{
iovp->iov_base = rpc_buffer (xprt);
iovp->iov_len = su->su_iosz;
mesgp->msg_iov = iovp;
mesgp->msg_iovlen = 1;
mesgp->msg_name = &(xprt->xp_raddr);
mesgp->msg_namelen = len;
mesgp->msg_control = &xprt->xp_pad [sizeof (struct iovec)
+ sizeof (struct msghdr)];
mesgp->msg_controllen = sizeof(xprt->xp_pad)
- sizeof (struct iovec) - sizeof (struct msghdr);
rlen = __recvmsg (xprt->xp_sock, mesgp, 0);
if (rlen >= 0)
{
struct cmsghdr *cmsg;
len = mesgp->msg_namelen;
cmsg = CMSG_FIRSTHDR (mesgp);
if (cmsg == NULL
|| CMSG_NXTHDR (mesgp, cmsg) != NULL
|| cmsg->cmsg_level != SOL_IP
|| cmsg->cmsg_type != IP_PKTINFO
|| cmsg->cmsg_len < (sizeof (struct cmsghdr)
+ sizeof (struct in_pktinfo)))
{
/* Not a simple IP_PKTINFO, ignore it. */
mesgp->msg_control = NULL;
mesgp->msg_controllen = 0;
}
else
{
/* It was a simple IP_PKTIFO as we expected, discard the
interface field. */
struct in_pktinfo *pkti = (struct in_pktinfo *) CMSG_DATA (cmsg);
pkti->ipi_ifindex = 0;
}
}
}
else
#endif
rlen = __recvfrom (xprt->xp_sock, rpc_buffer (xprt),
(int) su->su_iosz, 0,
(struct sockaddr *) &(xprt->xp_raddr), &len);
xprt->xp_addrlen = len;
if (rlen == -1)
{
if (errno == EINTR)
goto again;
__svc_accept_failed ();
}
if (rlen < 16) /* < 4 32-bit ints? */
return FALSE;
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))
{
#ifdef IP_PKTINFO
if (mesgp->msg_iovlen)
{
iovp->iov_base = reply;
iovp->iov_len = replylen;
(void) __sendmsg (xprt->xp_sock, mesgp, 0);
}
else
#endif
(void) __sendto (xprt->xp_sock, reply, (int) replylen, 0,
(struct sockaddr *) &xprt->xp_raddr, len);
return TRUE;
}
}
return TRUE;
}
static bool_t
svcudp_reply (SVCXPRT *xprt, struct rpc_msg *msg)
{
struct svcudp_data *su = su_data (xprt);
XDR *xdrs = &(su->su_xdrs);
int slen, sent;
bool_t stat = FALSE;
#ifdef IP_PKTINFO
struct iovec *iovp;
struct msghdr *mesgp;
#endif
xdrs->x_op = XDR_ENCODE;
XDR_SETPOS (xdrs, 0);
msg->rm_xid = su->su_xid;
if (xdr_replymsg (xdrs, msg))
{
slen = (int) XDR_GETPOS (xdrs);
#ifdef IP_PKTINFO
mesgp = (struct msghdr *) &xprt->xp_pad [sizeof (struct iovec)];
if (mesgp->msg_iovlen)
{
iovp = (struct iovec *) &xprt->xp_pad [0];
iovp->iov_base = rpc_buffer (xprt);
iovp->iov_len = slen;
sent = __sendmsg (xprt->xp_sock, mesgp, 0);
}
else
#endif
sent = __sendto (xprt->xp_sock, rpc_buffer (xprt), slen, 0,
(struct sockaddr *) &(xprt->xp_raddr),
xprt->xp_addrlen);
if (sent == slen)
{
stat = TRUE;
if (su->su_cache && slen >= 0)
{
cache_set (xprt, (u_long) slen);
}
}
}
return stat;
}
static bool_t
svcudp_getargs (SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)
{
return (*xdr_args) (&(su_data (xprt)->su_xdrs), args_ptr);
}
static bool_t
svcudp_freeargs (SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)
{
XDR *xdrs = &(su_data (xprt)->su_xdrs);
xdrs->x_op = XDR_FREE;
return (*xdr_args) (xdrs, args_ptr);
}
static void
svcudp_destroy (SVCXPRT *xprt)
{
struct svcudp_data *su = su_data (xprt);
xprt_unregister (xprt);
(void) __close (xprt->xp_sock);
XDR_DESTROY (&(su->su_xdrs));
mem_free (rpc_buffer (xprt), su->su_iosz);
mem_free ((caddr_t) su, sizeof (struct svcudp_data));
mem_free ((caddr_t) xprt, sizeof (SVCXPRT));
}
/***********this could be a separate file*********************/
/*
* Fifo cache for udp server
* Copies pointers to reply buffers into fifo cache
* Buffers are sent again if retransmissions are detected.
*/
#define SPARSENESS 4 /* 75% sparse */
#define CACHE_PERROR(msg) \
(void) __fxprintf(NULL, "%s\n", msg)
#define ALLOC(type, size) \
(type *) mem_alloc((unsigned) (sizeof(type) * (size)))
#define CALLOC(type, size) \
(type *) calloc (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_long cache_xid;
u_long cache_proc;
u_long cache_vers;
u_long cache_prog;
struct sockaddr_in cache_addr;
/*
* The cached reply and length
*/
char *cache_reply;
u_long cache_replylen;
/*
* Next node on the list, if there is a collision
*/
cache_ptr cache_next;
};
/*
* The entire cache
*/
struct udp_cache
{
u_long 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_long uc_nextvictim; /* points to next victim in fifo list */
u_long uc_prog; /* saved program number */
u_long uc_vers; /* saved version number */
u_long uc_proc; /* saved procedure number */
struct sockaddr_in uc_addr; /* saved caller's address */
};
/*
* the hashing function
*/
#define CACHE_LOC(transp, xid) \
(xid % (SPARSENESS*((struct udp_cache *) su_data(transp)->su_cache)->uc_size))
/*
* Enable use of the cache.
* Note: there is no disable.
*/
int
svcudp_enablecache (SVCXPRT *transp, u_long size)
{
struct svcudp_data *su = su_data (transp);
struct udp_cache *uc;
if (su->su_cache != NULL)
{
CACHE_PERROR (_("enablecache: cache already enabled"));
return 0;
}
uc = ALLOC (struct udp_cache, 1);
if (uc == NULL)
{
CACHE_PERROR (_("enablecache: could not allocate cache"));
return 0;
}
uc->uc_size = size;
uc->uc_nextvictim = 0;
uc->uc_entries = CALLOC (cache_ptr, size * SPARSENESS);
if (uc->uc_entries == NULL)
{
mem_free (uc, sizeof (struct udp_cache));
CACHE_PERROR (_("enablecache: could not allocate cache data"));
return 0;
}
uc->uc_fifo = CALLOC (cache_ptr, size);
if (uc->uc_fifo == NULL)
{
mem_free (uc->uc_entries, size * SPARSENESS);
mem_free (uc, sizeof (struct udp_cache));
CACHE_PERROR (_("enablecache: could not allocate cache fifo"));
return 0;
}
su->su_cache = (char *) uc;
return 1;
}
libc_hidden_nolink_sunrpc (svcudp_enablecache, GLIBC_2_0)
/*
* Set an entry in the cache
*/
static void
cache_set (SVCXPRT *xprt, u_long replylen)
{
cache_ptr victim;
cache_ptr *vicp;
struct svcudp_data *su = su_data (xprt);
struct udp_cache *uc = (struct udp_cache *) su->su_cache;
u_int loc;
char *newbuf;
/*
* 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)
{
CACHE_PERROR (_("cache_set: victim not found"));
return;
}
*vicp = victim->cache_next; /* remote from cache */
newbuf = victim->cache_reply;
}
else
{
victim = ALLOC (struct cache_node, 1);
if (victim == NULL)
{
CACHE_PERROR (_("cache_set: victim alloc failed"));
return;
}
newbuf = mem_alloc (su->su_iosz);
if (newbuf == NULL)
{
mem_free (victim, sizeof (struct cache_node));
CACHE_PERROR (_("cache_set: could not allocate new rpc_buffer"));
return;
}
}
/*
* Store it away
*/
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 = uc->uc_addr;
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;
}
/*
* Try to get an entry from the cache
* return 1 if found, 0 if not found
*/
static int
cache_get (SVCXPRT *xprt, struct rpc_msg *msg, char **replyp,
u_long *replylenp)
{
u_int loc;
cache_ptr ent;
struct svcudp_data *su = su_data (xprt);
struct udp_cache *uc = (struct udp_cache *) su->su_cache;
#define EQADDR(a1, a2) (memcmp((char*)&a1, (char*)&a2, sizeof(a1)) == 0)
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 == uc->uc_proc &&
ent->cache_vers == uc->uc_vers &&
ent->cache_prog == uc->uc_prog &&
EQADDR (ent->cache_addr, uc->uc_addr))
{
*replyp = ent->cache_reply;
*replylenp = ent->cache_replylen;
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;
memcpy (&uc->uc_addr, &xprt->xp_raddr, sizeof (uc->uc_addr));
return 0;
}
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