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

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      inet_connect 3
   6 /* SUMMARY
   7 /*      connect to TCP listener
   8 /* SYNOPSIS
   9 /*      #include <connect.h>
  10 /*
  11 /*      int     inet_windowsize;
  12 /*
  13 /*      int     inet_connect(addr, block_mode, timeout)
  14 /*      const char *addr;
  15 /*      int     block_mode;
  16 /*      int     timeout;
  17 /* DESCRIPTION
  18 /*      inet_connect connects to a TCP listener at
  19 /*      the specified address, and returns the resulting file descriptor.
  20 /*
  21 /*      Specify an inet_windowsize value > 0 to override the TCP
  22 /*      window size that the client advertises to the server.
  23 /*
  24 /*      Arguments:
  25 /* .IP addr
  26 /*      The destination to connect to. The format is host:port. If no
  27 /*      host is specified, a port on the local host is assumed.
  28 /*      Host and port information may be given in numerical form
  29 /*      or as symbolical names.
  30 /* .IP block_mode
  31 /*      Either NON_BLOCKING for a non-blocking socket, or BLOCKING for
  32 /*      blocking mode.
  33 /* .IP timeout
  34 /*      Bounds the number of seconds that the operation may take. Specify
  35 /*      a value <= 0 to disable the time limit.
  36 /* DIAGNOSTICS
  37 /*      The result is -1 when the connection could not be made.
  38 /*      The nature of the error is available via the global \fIerrno\fR
  39 /*      variable.
  40 /*      Fatal errors: other system call failures.
  41 /* LICENSE
  42 /* .ad
  43 /* .fi
  44 /*      The Secure Mailer license must be distributed with this software.
  45 /* AUTHOR(S)
  46 /*      Wietse Venema
  47 /*      IBM T.J. Watson Research
  48 /*      P.O. Box 704
  49 /*      Yorktown Heights, NY 10598, USA
  50 /*--*/
  51
  52 /* System interfaces. */
  53
  54 #include <sys_defs.h>
  55 #include <sys/socket.h>
  56 #include <netinet/in.h>
  57 #include <string.h>
  58 #include <unistd.h>
  59 #include <errno.h>
  60 #include <netdb.h>
  61
  62 /* Utility library. */
  63
  64 #include "mymalloc.h"
  65 #include "msg.h"
  66 #include "iostuff.h"
  67 #include "host_port.h"
  68 #include "sane_connect.h"
  69 #include "connect.h"
  70 #include "timed_connect.h"
  71 #include "myaddrinfo.h"
  72 #include "sock_addr.h"
  73 #include "inet_proto.h"
  74
  75 static int inet_connect_one(struct addrinfo *, int, int);
  76
  77 /* inet_connect - connect to TCP listener */
  78
  79 int     inet_connect(const char *addr, int block_mode, int timeout)
  80 {
  81     char   *buf;
  82     char   *host;
  83     char   *port;
  84     const char *parse_err;
  85     struct addrinfo *res;
  86     struct addrinfo *res0;
  87     int     aierr;
  88     int     sock;
  89     MAI_HOSTADDR_STR hostaddr;
  90     INET_PROTO_INFO *proto_info;
  91     int     found;
  92
  93     /*
  94      * Translate address information to internal form. No host defaults to
  95      * the local host.
  96      */
  97     buf = mystrdup(addr);
  98     if ((parse_err = host_port(buf, &host, "localhost", &port, (char *) 0)) != 0)
  99         msg_fatal("%s: %s", addr, parse_err);
 100     if ((aierr = hostname_to_sockaddr(host, port, SOCK_STREAM, &res0)) != 0)
 101         msg_fatal("host/service %s/%s not found: %s",
 102                   host, port, MAI_STRERROR(aierr));
 103     myfree(buf);
 104
 105     proto_info = inet_proto_info();
 106     for (sock = -1, found = 0, res = res0; res != 0; res = res->ai_next) {
 107
 108         /*
 109          * Safety net.
 110          */
 111         if (strchr((char *) proto_info->sa_family_list, res->ai_family) == 0) {
 112             msg_info("skipping address family %d for host %s",
 113                      res->ai_family, host);
 114             continue;
 115         }
 116         found++;
 117
 118         /*
 119          * In case of multiple addresses, show what address we're trying now.
 120          */
 121         if (msg_verbose) {
 122             SOCKADDR_TO_HOSTADDR(res->ai_addr, res->ai_addrlen,
 123                                  &hostaddr, (MAI_SERVPORT_STR *) 0, 0);
 124             msg_info("trying... [%s]", hostaddr.buf);
 125         }
 126         if ((sock = inet_connect_one(res, block_mode, timeout)) < 0) {
 127             if (msg_verbose)
 128                 msg_info("%m");
 129         } else
 130             break;
 131     }
 132     if (found == 0)
 133         msg_fatal("host not found: %s", addr);
 134     freeaddrinfo(res0);
 135     return (sock);
 136 }
 137
 138 /* inet_connect_one - try to connect to one address */
 139
 140 static int inet_connect_one(struct addrinfo * res, int block_mode, int timeout)
 141 {
 142     int     sock;
 143
 144     /*
 145      * Create a client socket.
 146      */
 147     sock = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
 148     if (sock < 0)
 149         return (-1);
 150
 151     /*
 152      * Window scaling workaround.
 153      */
 154     if (inet_windowsize > 0)
 155         set_inet_windowsize(sock, inet_windowsize);
 156
 157     /*
 158      * Timed connect.
 159      */
 160     if (timeout > 0) {
 161         non_blocking(sock, NON_BLOCKING);
 162         if (timed_connect(sock, res->ai_addr, res->ai_addrlen, timeout) < 0) {
 163             close(sock);
 164             return (-1);
 165         }
 166         if (block_mode != NON_BLOCKING)
 167             non_blocking(sock, block_mode);
 168         return (sock);
 169     }
 170
 171     /*
 172      * Maybe block until connected.
 173      */
 174     else {
 175         non_blocking(sock, block_mode);
 176         if (sane_connect(sock, res->ai_addr, res->ai_addrlen) < 0
 177             && errno != EINPROGRESS) {
 178             close(sock);
 179             return (-1);
 180         }
 181         return (sock);
 182     }
 183 }