Commit fa57a8a7 authored by Daniel Stenberg's avatar Daniel Stenberg
Browse files

Ben Greear's SO_BINDTODEVICE patch that binds to a network interface "even 

more" when the previous approach. Known to work on Linux, possibly on other
platforms as well.
parent eb4d65d0

lib/connect.c

+32 −2
Original line number Diff line number Diff line
@@ -228,6 +228,7 @@ static CURLcode bindlocal(struct connectdata *conn, 
    char myhost[256] = "";

    in_addr_t in;

    int rc;

    bool was_iface = FALSE;



    /* First check if the given name is an IP address */

    in=inet_addr(data->set.device);
@@ -239,7 +240,10 @@ static CURLcode bindlocal(struct connectdata *conn, 
       */

      rc = Curl_resolv(conn, myhost, 0, &h);

      if(rc == 1)

        rc = Curl_wait_for_resolv(conn, &h);

        (void)Curl_wait_for_resolv(conn, &h);



      if(h)

        was_iface = TRUE;



    }

    else {
@@ -250,7 +254,7 @@ static CURLcode bindlocal(struct connectdata *conn, 
         */

        rc = Curl_resolv(conn, data->set.device, 0, &h);

        if(rc == 1)

          rc = Curl_wait_for_resolv(conn, &h);

          (void)Curl_wait_for_resolv(conn, &h);



        if(h)

          /* we know data->set.device is shorter than the myhost array */
@@ -266,11 +270,37 @@ static CURLcode bindlocal(struct connectdata *conn, 
         hostent_buf,

         sizeof(hostent_buf));

      */

      failf(data, "Couldn't bind to '%s'", data->set.device);

      return CURLE_HTTP_PORT_FAILED;

    }



    infof(data, "We bind local end to %s\n", myhost);



#ifdef SO_BINDTODEVICE

    /* I am not sure any other OSs than Linux that provide this feature, and

     * at the least I cannot test. --Ben

     *

     * This feature allows one to tightly bind the local socket to a

     * particular interface.  This will force even requests to other local

     * interfaces to go out the external interface.

     *

     */

    if (was_iface) {

      /* Only bind to the interface when specified as interface, not just as a

       * hostname or ip address.

       */

      if (setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE,

                     data->set.device, strlen(data->set.device)+1) != 0) {

        /* printf("Failed to BINDTODEVICE, socket: %d  device: %s error: %s\n",

           sockfd, data->set.device, strerror(errno)); */

        infof(data, "SO_BINDTODEVICE %s failed\n",

              data->set.device);

        /* This is typiclally "errno 1, error: Operation not permitted" if

           you're not running as root or another suitable privileged user */

      }

    }

#endif



    in=inet_addr(myhost);

    if (CURL_INADDR_NONE != in) {