/*

 * 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) 2012-2018 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

 * <http://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;

}