svc_udp.c

Axis 221 camera embedded programing interface

  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 (xprt, xdr_args, args_ptr)
     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 (xprt, xdr_args, args_ptr)
     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 (xprt)
     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 */

#ifdef USE_IN_LIBIO
# define CACHE_PERROR(msg)	\
	if (_IO_fwide (stderr, 0) > 0)					      \
		(void) __fwprintf(stderr, L"%s\n", msg);		      \
	else								      \
		(void) fprintf(stderr, "%s\n", msg)
#else
# define CACHE_PERROR(msg)	\
	(void) fprintf(stderr,"%s\n", msg)
#endif

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

#define BZERO(addr, type, size)	 \
	memset((char *) addr, 0, sizeof(type) * (int) (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 = ALLOC (cache_ptr, size * SPARSENESS);
  if (uc->uc_entries == NULL)
    {
      CACHE_PERROR (_("enablecache: could not allocate cache data"));
      return 0;
    }
  BZERO (uc->uc_entries, cache_ptr, size * SPARSENESS);
  uc->uc_fifo = ALLOC (cache_ptr, size);
  if (uc->uc_fifo == NULL)
    {
      CACHE_PERROR (_("enablecache: could not allocate cache fifo"));
      return 0;
    }
  BZERO (uc->uc_fifo, cache_ptr, size);
  su->su_cache = (char *) uc;
  return 1;
}


/*
 * 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)
	{
	  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 (xprt, msg, replyp, replylenp)
     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;
}