external/ibm-public/postfix/dist/src/util/sane_connect.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      sane_connect 3
   6 /* SUMMARY
   7 /*      sanitize connect() results
   8 /* SYNOPSIS
   9 /*      #include <sane_connect.h>
  10 /*
  11 /*      int     sane_connect(sock, buf, len)
  12 /*      int     sock;
  13 /*      struct sockaddr *buf;
  14 /*      SOCKADDR_SIZE *len;
  15 /* DESCRIPTION
  16 /*      sane_connect() implements the connect(2) socket call, and maps
  17 /*      known harmless error results to EAGAIN.
  18 /* BUGS
  19 /*      Bizarre systems may have other harmless error results. Such
  20 /*      systems encourage programmers to ignore error results, and
  21 /*      penalize programmers who code defensively.
  22 /* LICENSE
  23 /* .ad
  24 /* .fi
  25 /*      The Secure Mailer license must be distributed with this software.
  26 /* AUTHOR(S)
  27 /*      Wietse Venema
  28 /*      IBM T.J. Watson Research
  29 /*      P.O. Box 704
  30 /*      Yorktown Heights, NY 10598, USA
  31 /*--*/
  32
  33 /* System library. */
  34
  35 #include "sys_defs.h"
  36 #include <sys/socket.h>
  37 #include <errno.h>
  38
  39 /* Utility library. */
  40
  41 #include "msg.h"
  42 #include "sane_connect.h"
  43
  44 /* sane_connect - sanitize connect() results */
  45
  46 int     sane_connect(int sock, struct sockaddr * sa, SOCKADDR_SIZE len)
  47 {
  48
  49     /*
  50      * XXX Solaris select() produces false read events, so that read() blocks
  51      * forever on a blocking socket, and fails with EAGAIN on a non-blocking
  52      * socket. Turning on keepalives will fix a blocking socket provided that
  53      * the kernel's keepalive timer expires before the Postfix watchdog
  54      * timer.
  55      *
  56      * XXX Work around NAT induced damage by sending a keepalive before an idle
  57      * connection is expired. This requires that the kernel keepalive timer
  58      * is set to a short time, like 100s.
  59      */
  60     if (sa->sa_family == AF_INET) {
  61         int     on = 1;
  62
  63         (void) setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
  64                           (char *) &on, sizeof(on));
  65     }
  66     return (connect(sock, sa, len));
  67 }