tsend.c

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/*
 * $Id: tsend.c 4518 2008-07-28 15:39:28Z henningw $
 *
 * Copyright (C) 2001-2003 FhG Fokus
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version
 *
 * Kamailio 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *
 * send with timeout for stream and datagram sockets
 * 
 * History:
 * --------
 *  2004-02-26  created by andrei
 *  2003-03-03  switched to heavy macro use, added tsend_dgram_ev (andrei) 
 */

#include <string.h>
#include <errno.h>
#include <sys/poll.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/uio.h>

#include "dprint.h"

/* the functions below are very similar => some generic macros */
#define TSEND_INIT \
   int n; \
   struct pollfd pf; \
   pf.fd=fd; \
   pf.events=POLLOUT

#define TSEND_POLL(f_name) \
poll_loop: \
   while(1){ \
      n=poll(&pf, 1, timeout); \
      if (n<0){ \
         if (errno==EINTR) continue; /* signal, ignore */ \
         LM_ERR(f_name ": poll failed: %s [%d]\n", \
               strerror(errno), errno); \
         goto error; \
      }else if (n==0){ \
         /* timeout */ \
         LM_ERR(f_name ": send timeout (%d)\n", timeout); \
         goto error; \
      } \
      if (pf.revents&POLLOUT){ \
         /* we can write again */ \
         goto again; \
      }else if (pf.revents&(POLLERR|POLLHUP|POLLNVAL)){ \
         LM_ERR(f_name ": bad poll flags %x\n", \
               pf.revents); \
         goto error; \
      } \
      /* if POLLIN or POLLPRI or other non-harmful events happened,    \
       * continue ( although poll should never signal them since we're  \
       * not interested in them => we should never reach this point) */ \
   } 


#define TSEND_ERR_CHECK(f_name)\
   if (n<0){ \
      if (errno==EINTR) goto again; \
      else if (errno!=EAGAIN && errno!=EWOULDBLOCK){ \
         LM_ERR(f_name ": failed to send: (%d) %s\n", \
               errno, strerror(errno)); \
         goto error; \
      }else goto poll_loop; \
   }
   


/*! \brief sends on fd (which must be O_NONBLOCK); if it cannot send any data
 * in timeout milliseconds it will return ERROR
 * \return -1 on error, or number of bytes written
 *  (if less than len => couldn't send all)
 *  bugs: signals will reset the timer
 */
int tsend_stream(int fd, char* buf, unsigned int len, int timeout)
{
   int written;
   TSEND_INIT;
   
   written=0;
again:
   n=send(fd, buf, len,
#ifdef HAVE_MSG_NOSIGNAL
         MSG_NOSIGNAL
#else
         0
#endif
      );
   TSEND_ERR_CHECK("tsend_stream");
   written+=n; 
   if ((unsigned int)n<len){ 
      /* partial write */ 
      buf+=n; 
      len-=n; 
   }else{ 
      /* successful full write */ 
      return written;
   }
   TSEND_POLL("tsend_stream");
error:
   return -1;
}



/*! \brief sends on dgram fd (which must be O_NONBLOCK); if it cannot send any data
 * in timeout milliseconds it will return ERROR
 * \return -1 on error, or number of bytes written
 *  (if less than len => couldn't send all)
 *  bugs: signals will reset the timer
 */
int tsend_dgram(int fd, char* buf, unsigned int len, 
            const struct sockaddr* to, socklen_t tolen, int timeout)
{
   TSEND_INIT;
again:
   n=sendto(fd, buf, len, 0, to, tolen);
   TSEND_ERR_CHECK("tsend_dgram");
   /* we don't care about partial writes: they shouldn't happen on 
    * a datagram socket */
   return n;
   TSEND_POLL("tsend_datagram");
error:
   return -1;
}

   
/*! \brief sends on connected datagram fd (which must be O_NONBLOCK); 
 * if it cannot send any data in timeout milliseconds it will return ERROR
 * \return -1 on error, or number of bytes written
 *  (if less than len => couldn't send all)
 *  bugs: signals will reset the timer
 */
int tsend_dgram_ev(int fd, const struct iovec* v, int count, int timeout)
{
   TSEND_INIT;
again:
   n=writev(fd, v, count);
   TSEND_ERR_CHECK("tsend_datagram_ev");
   return n;
   TSEND_POLL("tsend_datagram_ev");
error:
   return -1;
}

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