Allow to specify UDPv4/6 multicast interface

[paraslash.git] / udp_send.c

diff --git a/udp_send.c b/udp_send.c
index b0f55bc35c7ccb661b6db32997a88fc9284ed98e..140458e7ed9b1d4e3a03d05c2e26a6b36d66db54 100644 (file)
--- a/udp_send.c
+++ b/udp_send.c
@@ -68,19 +68,107 @@ static void udp_delete_target(struct udp_target *ut, const char *msg)
        free(ut);
 }
 
        free(ut);
 }
 

+/**
+ * Perform AF-independent multicast sender setup.
+ *
+ * \param fd   The connected socket descriptor.
+ * \param ttl  UDPv4 multicast TTL or UDPv6 multicast number of hops.
+ *             Use -1 to mean default, 0..255 otherwise.
+ * \param iface        The outgoing multicast interface, or NULL for the default.
+ *
+ * \return Zero if okay, negative on error.
+ */
+static int mcast_sender_setup(struct udp_target *ut, int ttl, char *iface)
+{
+       struct sockaddr_storage ss;
+       socklen_t sslen = sizeof(ss);
+
+       const int on = 1;
+       int id = iface == NULL ? 0 : if_nametoindex(iface);
+
+       if (getpeername(ut->fd, (struct sockaddr *)&ss, &sslen) < 0)
+               goto err;
+
+       if (iface != NULL && id == 0)
+               PARA_WARNING_LOG("could not resolve interface %s, using default", iface);
+
+       /* RFC 3493, 5.2: -1 means 'use kernel default' */
+       if (ttl < 0 || ttl > 255)
+               ttl = -1;
+
+       switch (ss.ss_family) {
+       case AF_INET:
+               if (!IN_MULTICAST(htonl(((struct sockaddr_in *)&ss)->sin_addr.s_addr)))
+                       return 0;
+               if (id != 0) {
+#ifdef HAVE_IP_MREQN
+                       struct ip_mreqn mn;
+
+                       memset(&mn, 0, sizeof(mn));
+                       mn.imr_ifindex = id;
+                       if (setsockopt(ut->fd, IPPROTO_IP, IP_MULTICAST_IF, &mn, sizeof(mn)) < 0)
+                               goto err;
+#else
+                       PARA_ERROR_LOG("No support for setting outgoing IPv4 mcast interface.");
+#endif
+               }
+               /*
+                * Enable receiving multicast messages generated on the local host
+                * At least on Linux, this is enabled by default.
+                */
+               if (setsockopt(ut->fd, IPPROTO_IP, IP_MULTICAST_LOOP, &on, sizeof(on)) < 0)
+                       break;
+
+               /* Default: use local subnet (do not flood out into the WAN) */
+               if (ttl == -1)
+                       ttl = 1;
+               if (setsockopt(ut->fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) < 0)
+                       break;
+               return 0;
+       case AF_INET6:
+               if (!IN6_IS_ADDR_MULTICAST(&((struct sockaddr_in6 *)&ss)->sin6_addr))
+                       return 0;
+               if (id != 0 &&
+                   setsockopt(ut->fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &id, sizeof(id)) < 0)
+                       break;
+               if (setsockopt(ut->fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &on, sizeof(on)) < 0)
+                       break;
+               if (setsockopt(ut->fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl)) < 0)
+                       break;
+               return 0;
+       default:
+               PARA_ERROR_LOG("address family %d not supported", ss.ss_family);
+               return -E_ADDRESS_LOOKUP;
+       }
+err:
+       return -ERRNO_TO_PARA_ERROR(errno);
+}
+
+/** The maximal size of the per-target chunk queue. */

 #define UDP_CQ_BYTES 40000
 
 static int udp_init_session(struct udp_target *ut)
 {
        int ret;
 #define UDP_CQ_BYTES 40000
 
 static int udp_init_session(struct udp_target *ut)
 {
        int ret;

+       char *iface = NULL;

 
        if (ut->fd >= 0) /* nothing to do */
                return 0;
 
        if (ut->fd >= 0) /* nothing to do */
                return 0;

-       ret = create_udp_send_socket(TARGET_ADDR(ut), ut->port,
-               conf.udp_ttl_arg);
+
+       ret = makesock(AF_UNSPEC, IPPROTO_UDP, 0, TARGET_ADDR(ut), ut->port);

        if (ret < 0)
                return ret;
        ut->fd = ret;
        if (ret < 0)
                return ret;
        ut->fd = ret;

+
+       if (conf.udp_mcast_iface_given)
+               iface = conf.udp_mcast_iface_arg;
+
+       ret = mcast_sender_setup(ut, conf.udp_ttl_arg, iface);
+       if (ret < 0) {
+               close(ut->fd);
+               return ret;
+       }
+

        ret = mark_fd_nonblocking(ut->fd);
        if (ret < 0) {
                close(ut->fd);
        ret = mark_fd_nonblocking(ut->fd);
        if (ret < 0) {
                close(ut->fd);