Add support for multicast communication with UML/QEMU/KVM.
[tinc] / src / multicast_device.c
diff --git a/src/multicast_device.c b/src/multicast_device.c
new file mode 100644 (file)
index 0000000..392fd37
--- /dev/null
@@ -0,0 +1,216 @@
+/*
+    device.c -- multicast socket
+    Copyright (C) 2002-2005 Ivo Timmermans,
+                  2002-2012 Guus Sliepen <guus@tinc-vpn.org>
+
+    This program 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.
+
+    This program 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.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "system.h"
+
+#include "conf.h"
+#include "device.h"
+#include "net.h"
+#include "logger.h"
+#include "netutl.h"
+#include "utils.h"
+#include "route.h"
+#include "xalloc.h"
+
+static char *device_info;
+
+static uint64_t device_total_in = 0;
+static uint64_t device_total_out = 0;
+
+static struct addrinfo *ai = NULL;
+static mac_t ignore_src = {0};
+
+static bool setup_device(void) {
+       char *host;
+       char *port;
+       char *space;
+       int ttl = 1;
+
+       device_info = "multicast socket";
+
+       get_config_string(lookup_config(config_tree, "Interface"), &iface);
+
+       if(!get_config_string(lookup_config(config_tree, "Device"), &device)) {
+               logger(LOG_ERR, "Device variable required for %s", device_info);
+               return false;
+       }
+
+       host = xstrdup(device);
+       space = strchr(host, ' ');
+       if(!space) {
+               logger(LOG_ERR, "Port number required for %s", device_info);
+               return false;
+       }
+
+       *space++ = 0;
+       port = space;
+       space = strchr(port, ' ');
+
+       if(space) {
+               *space++ = 0;
+               ttl = atoi(space);
+       }
+
+       ai = str2addrinfo(host, port, SOCK_DGRAM);
+       if(!ai)
+               return false;
+
+       device_fd = socket(ai->ai_family, SOCK_DGRAM, IPPROTO_UDP);
+       if(device_fd < 0) {
+               logger(LOG_ERR, "Creating socket failed: %s", sockstrerror(sockerrno));
+               return false;
+       }
+
+#ifdef FD_CLOEXEC
+       fcntl(device_fd, F_SETFD, FD_CLOEXEC);
+#endif
+
+       static const int one = 1;
+       setsockopt(device_fd, SOL_SOCKET, SO_REUSEADDR, (void *)&one, sizeof one);
+
+       if(bind(device_fd, ai->ai_addr, ai->ai_addrlen)) {
+               closesocket(device_fd);
+               logger(LOG_ERR, "Can't bind to %s %s: %s", host, port, sockstrerror(sockerrno));
+               return false;
+       }
+
+       switch(ai->ai_family) {
+               case AF_INET: {
+                       struct ip_mreq mreq;
+                       struct sockaddr_in in;
+                       memcpy(&in, ai->ai_addr, sizeof in);
+                       mreq.imr_multiaddr.s_addr = in.sin_addr.s_addr;
+                       mreq.imr_interface.s_addr = htonl(INADDR_ANY);
+                       if(setsockopt(device_fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof mreq)) {
+                               logger(LOG_ERR, "Cannot join multicast group %s %s: %s", host, port, sockstrerror(sockerrno));
+                               closesocket(device_fd);
+                               return false;
+                       }
+                       setsockopt(device_fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof one);
+                       setsockopt(device_fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof ttl);
+               } break;
+
+               case AF_INET6: {
+                       struct ipv6_mreq mreq;
+                       struct sockaddr_in6 in6;
+                       memcpy(&in6, ai->ai_addr, sizeof in6);
+                       memcpy(&mreq.ipv6mr_multiaddr, &in6.sin6_addr, sizeof mreq.ipv6mr_multiaddr);
+                       mreq.ipv6mr_interface = 0;
+                       if(setsockopt(device_fd, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq, sizeof mreq)) {
+                               logger(LOG_ERR, "Cannot join multicast group %s %s: %s", host, port, sockstrerror(sockerrno));
+                               closesocket(device_fd);
+                               return false;
+                       }
+                       setsockopt(device_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof one);
+                       setsockopt(device_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof ttl);
+               } break;
+       
+               default:
+                       logger(LOG_ERR, "Multicast for address family %hx unsupported", ai->ai_family);
+                       closesocket(device_fd);
+                       return false;
+       }
+
+       logger(LOG_INFO, "%s is a %s", device, device_info);
+
+       return true;
+}
+
+static void close_device(void) {
+       close(device_fd);
+
+       free(device);
+       free(iface);
+
+       if(ai)
+               freeaddrinfo(ai);
+}
+
+static bool read_packet(vpn_packet_t *packet) {
+       int lenin;
+
+       if((lenin = recv(device_fd, packet->data, MTU, 0)) <= 0) {
+               logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
+                          device, strerror(errno));
+               return false;
+       }
+
+       if(!memcmp(&ignore_src, packet->data + 6, sizeof ignore_src)) {
+               ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Ignoring loopback packet of %d bytes from %s", lenin, device_info);
+               packet->len = 0;
+               return true;
+       }
+
+       packet->len = lenin;
+
+       device_total_in += packet->len;
+
+       ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
+                          device_info);
+
+       return true;
+}
+
+static bool write_packet(vpn_packet_t *packet) {
+       ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
+                          packet->len, device_info);
+
+       if(sendto(device_fd, packet->data, packet->len, 0, ai->ai_addr, ai->ai_addrlen) < 0) {
+               logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
+                          strerror(errno));
+               return false;
+       }
+
+       device_total_out += packet->len;
+
+       memcpy(&ignore_src, packet->data + 6, sizeof ignore_src);
+
+       return true;
+}
+
+static void dump_device_stats(void) {
+       logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
+       logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
+       logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
+}
+
+const devops_t multicast_devops = {
+       .setup = setup_device,
+       .close = close_device,
+       .read = read_packet,
+       .write = write_packet,
+       .dump_stats = dump_device_stats,
+};
+
+#if 0
+
+static bool not_supported(void) {
+       logger(LOG_ERR, "Raw socket device not supported on this platform");
+       return false;
+}
+
+const devops_t multicast_devops = {
+       .setup = not_supported,
+       .close = NULL,
+       .read = NULL,
+       .write = NULL,
+       .dump_stats = NULL,
+};
+#endif