Drop libevent and use our own event handling again.
[tinc] / src / net_packet.c
index 88d791d..81ca70a 100644 (file)
@@ -77,10 +77,10 @@ bool localdiscovery = false;
    which will be broadcast to the local network.
 */
 
-static void send_mtu_probe_handler(int fd, short events, void *data) {
+static void send_mtu_probe_handler(void *data) {
        node_t *n = data;
        int timeout = 1;
-       
+
        n->mtuprobes++;
 
        if(!n->status.reachable || !n->status.validkey) {
@@ -97,6 +97,7 @@ static void send_mtu_probe_handler(int fd, short events, void *data) {
                }
 
                logger(DEBUG_TRAFFIC, LOG_INFO, "%s (%s) did not respond to UDP ping, restarting PMTU discovery", n->name, n->hostname);
+               n->status.udp_confirmed = false;
                n->mtuprobes = 1;
                n->minmtu = 0;
                n->maxmtu = MTU;
@@ -134,7 +135,7 @@ static void send_mtu_probe_handler(int fd, short events, void *data) {
 
                if(len < 64)
                        len = 64;
-               
+
                vpn_packet_t packet;
                memset(packet.data, 0, 14);
                randomize(packet.data + 14, len - 14);
@@ -150,22 +151,38 @@ static void send_mtu_probe_handler(int fd, short events, void *data) {
        }
 
 end:
-       event_add(&n->mtuevent, &(struct timeval){timeout, 0});
+       timeout_set(&n->mtutimeout, &(struct timeval){timeout, rand() % 100000});
 }
 
 void send_mtu_probe(node_t *n) {
-       if(!timeout_initialized(&n->mtuevent))
-               timeout_set(&n->mtuevent, send_mtu_probe_handler, n);
-       send_mtu_probe_handler(0, 0, n);
+       timeout_add(&n->mtutimeout, send_mtu_probe_handler, n, &(struct timeval){1, 0});
+       send_mtu_probe_handler(n);
 }
 
 static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
        logger(DEBUG_TRAFFIC, LOG_INFO, "Got MTU probe length %d from %s (%s)", packet->len, n->name, n->hostname);
 
        if(!packet->data[0]) {
+               /* It's a probe request, send back a reply */
+
                packet->data[0] = 1;
+
+               /* Temporarily set udp_confirmed, so that the reply is sent
+                  back exactly the way it came in. */
+
+               bool udp_confirmed = n->status.udp_confirmed;
+               n->status.udp_confirmed = true;
                send_udppacket(n, packet);
+               n->status.udp_confirmed = udp_confirmed;
        } else {
+               /* It's a valid reply: now we know bidirectional communication
+                  is possible using the address and socket that the reply
+                  packet used. */
+
+               n->status.udp_confirmed = true;
+
+               /* If we haven't established the PMTU yet, restart the discovery process. */
+
                if(n->mtuprobes > 30) {
                        if(n->minmtu)
                                n->mtuprobes = 30;
@@ -173,6 +190,8 @@ static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
                                n->mtuprobes = 1;
                }
 
+               /* If applicable, raise the minimum supported MTU */
+
                if(len > n->maxmtu)
                        len = n->maxmtu;
                if(n->minmtu < len)
@@ -209,7 +228,7 @@ static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t l
                return -1;
 #endif
        }
-       
+
        return -1;
 }
 
@@ -291,7 +310,7 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 
        if(digest_active(&n->indigest)) {
                inpkt->len -= n->indigest.maclength;
-               if(!digest_verify(&n->indigest, &inpkt->seqno, inpkt->len, (const char *)&inpkt->seqno + inpkt->len)) {
+               if(!digest_verify(&n->indigest, &inpkt->seqno, inpkt->len, (const char *)&inpkt->seqno + inpkt->len)) {
                        logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got unauthenticated packet from %s (%s)", n->name, n->hostname);
                        return;
                }
@@ -306,7 +325,7 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
                        logger(DEBUG_TRAFFIC, LOG_DEBUG, "Error decrypting packet from %s (%s)", n->name, n->hostname);
                        return;
                }
-               
+
                outpkt->len = outlen;
                inpkt = outpkt;
        }
@@ -325,12 +344,12 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
                                        return;
                                }
                                logger(DEBUG_ALWAYS, LOG_WARNING, "Lost %d packets from %s (%s)",
-                                               inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
+                                               inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
                                memset(n->late, 0, replaywin);
                        } else if (inpkt->seqno <= n->received_seqno) {
                                if((n->received_seqno >= replaywin * 8 && inpkt->seqno <= n->received_seqno - replaywin * 8) || !(n->late[(inpkt->seqno / 8) % replaywin] & (1 << inpkt->seqno % 8))) {
                                        logger(DEBUG_ALWAYS, LOG_WARNING, "Got late or replayed packet from %s (%s), seqno %d, last received %d",
-                                               n->name, n->hostname, inpkt->seqno, n->received_seqno);
+                                               n->name, n->hostname, inpkt->seqno, n->received_seqno);
                                        return;
                                }
                        } else {
@@ -345,7 +364,7 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 
        if(inpkt->seqno > n->received_seqno)
                n->received_seqno = inpkt->seqno;
-                       
+
        if(n->received_seqno > MAX_SEQNO)
                regenerate_key();
 
@@ -358,7 +377,7 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 
                if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, n->incompression)) < 0) {
                        logger(DEBUG_TRAFFIC, LOG_ERR, "Error while uncompressing packet from %s (%s)",
-                                                n->name, n->hostname);
+                                                n->name, n->hostname);
                        return;
                }
 
@@ -394,6 +413,7 @@ static void send_sptps_packet(node_t *n, vpn_packet_t *origpkt) {
                if(!n->status.waitingforkey)
                        send_req_key(n);
                else if(n->last_req_key + 10 < time(NULL)) {
+                       logger(DEBUG_ALWAYS, LOG_DEBUG, "No key from %s after 10 seconds, restarting SPTPS", n->name);
                        sptps_stop(&n->sptps);
                        n->status.waitingforkey = false;
                        send_req_key(n);
@@ -434,6 +454,84 @@ static void send_sptps_packet(node_t *n, vpn_packet_t *origpkt) {
        return;
 }
 
+static void choose_udp_address(const node_t *n, const sockaddr_t **sa, int *sock) {
+       /* Latest guess */
+       *sa = &n->address;
+       *sock = n->sock;
+
+       /* If the UDP address is confirmed, use it. */
+       if(n->status.udp_confirmed)
+               return;
+
+       /* Send every third packet to n->address; that could be set
+          to the node's reflexive UDP address discovered during key
+          exchange. */
+
+       static int x = 0;
+       if(++x >= 3) {
+               x = 0;
+               return;
+       }
+
+       /* Otherwise, address are found in edges to this node.
+          So we pick a random edge and a random socket. */
+
+       int i = 0;
+       int j = rand() % n->edge_tree->count;
+       edge_t *candidate = NULL;
+
+       for splay_each(edge_t, e, n->edge_tree) {
+               if(i++ == j) {
+                       candidate = e->reverse;
+                       break;
+               }
+       }
+
+       if(candidate) {
+               *sa = &candidate->address;
+               *sock = rand() % listen_sockets;
+       }
+
+       /* Make sure we have a suitable socket for the chosen address */
+       if(listen_socket[*sock].sa.sa.sa_family != (*sa)->sa.sa_family) {
+               for(int i = 0; i < listen_sockets; i++) {
+                       if(listen_socket[i].sa.sa.sa_family == (*sa)->sa.sa_family) {
+                               *sock = i;
+                               break;
+                       }
+               }
+       }
+}
+
+static void choose_broadcast_address(const node_t *n, const sockaddr_t **sa, int *sock) {
+       static sockaddr_t broadcast_ipv4 = {
+               .in = {
+                       .sin_family = AF_INET,
+                       .sin_addr.s_addr = -1,
+               }
+       };
+
+       static sockaddr_t broadcast_ipv6 = {
+               .in6 = {
+                       .sin6_family = AF_INET6,
+                       .sin6_addr.s6_addr[0x0] = 0xff,
+                       .sin6_addr.s6_addr[0x1] = 0x02,
+                       .sin6_addr.s6_addr[0xf] = 0x01,
+               }
+       };
+
+       *sock = rand() % listen_sockets;
+
+       if(listen_socket[*sock].sa.sa.sa_family == AF_INET6) {
+               broadcast_ipv6.in6.sin6_port = n->prevedge->address.in.sin_port;
+               broadcast_ipv6.in6.sin6_scope_id = listen_socket[*sock].sa.in6.sin6_scope_id;
+               *sa = &broadcast_ipv6;
+       } else {
+               broadcast_ipv4.in.sin_port = n->prevedge->address.in.sin_port;
+               *sa = &broadcast_ipv4;
+       }
+}
+
 static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
        vpn_packet_t pkt1, pkt2;
        vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
@@ -458,15 +556,13 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
        /* Make sure we have a valid key */
 
        if(!n->status.validkey) {
-               time_t now = time(NULL);
-
                logger(DEBUG_TRAFFIC, LOG_INFO,
                                   "No valid key known yet for %s (%s), forwarding via TCP",
                                   n->name, n->hostname);
 
-               if(n->last_req_key + 10 <= now) {
+               if(n->last_req_key + 10 <= now.tv_sec) {
                        send_req_key(n);
-                       n->last_req_key = now;
+                       n->last_req_key = now.tv_sec;
                }
 
                send_tcppacket(n->nexthop->connection, origpkt);
@@ -528,53 +624,29 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
                inpkt->len += digest_length(&n->outdigest);
        }
 
-       /* Determine which socket we have to use */
-
-       if(n->address.sa.sa_family != listen_socket[n->sock].sa.sa.sa_family) {
-               for(int sock = 0; sock < listen_sockets; sock++) {
-                       if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family) {
-                               n->sock = sock;
-                               break;
-                       }
-               }
-       }
-
        /* Send the packet */
 
-       struct sockaddr *sa;
-       socklen_t sl;
+       const sockaddr_t *sa;
        int sock;
 
        /* Overloaded use of priority field: -1 means local broadcast */
 
-       if(origpriority == -1 && n->prevedge) {
-               struct sockaddr_in in;
-               in.sin_family = AF_INET;
-               in.sin_addr.s_addr = -1;
-               in.sin_port = n->prevedge->address.in.sin_port;
-               sa = (struct sockaddr *)&in;
-               sl = sizeof in;
-               sock = 0;
-       } else {
-               if(origpriority == -1)
-                       origpriority = 0;
-
-               sa = &(n->address.sa);
-               sl = SALEN(n->address.sa);
-               sock = n->sock;
-       }
+       if(origpriority == -1 && n->prevedge)
+               choose_broadcast_address(n, &sa, &sock);
+       else
+               choose_udp_address(n, &sa, &sock);
 
 #if defined(SOL_IP) && defined(IP_TOS)
        if(priorityinheritance && origpriority != priority
           && listen_socket[n->sock].sa.sa.sa_family == AF_INET) {
                priority = origpriority;
                logger(DEBUG_TRAFFIC, LOG_DEBUG, "Setting outgoing packet priority to %d", priority);
-               if(setsockopt(listen_socket[n->sock].udp, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
+               if(setsockopt(listen_socket[n->sock].udp.fd, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
                        logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "setsockopt", strerror(errno));
        }
 #endif
 
-       if(sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, sa, sl) < 0 && !sockwouldblock(sockerrno)) {
+       if(sendto(listen_socket[sock].udp.fd, (char *) &inpkt->seqno, inpkt->len, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
                if(sockmsgsize(sockerrno)) {
                        if(n->maxmtu >= origlen)
                                n->maxmtu = origlen - 1;
@@ -591,28 +663,27 @@ end:
 bool send_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
        node_t *to = handle;
 
-       if(type >= SPTPS_HANDSHAKE
-                       || ((myself->options | to->options) & OPTION_TCPONLY)
-                       || (type != PKT_PROBE && len > to->minmtu)) {
+       /* Send it via TCP if it is a handshake packet, TCPOnly is in use, or this packet is larger than the MTU. */
+
+       if(type >= SPTPS_HANDSHAKE || ((myself->options | to->options) & OPTION_TCPONLY) || (type != PKT_PROBE && len > to->minmtu)) {
                char buf[len * 4 / 3 + 5];
                b64encode(data, buf, len);
+               /* If no valid key is known yet, send the packets using ANS_KEY requests,
+                  to ensure we get to learn the reflexive UDP address. */
                if(!to->status.validkey)
                        return send_request(to->nexthop->connection, "%d %s %s %s -1 -1 -1 %d", ANS_KEY, myself->name, to->name, buf, myself->incompression);
                else
-                       return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, type >= SPTPS_HANDSHAKE ? REQ_SPTPS : REQ_PACKET, buf);
+                       return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_SPTPS, buf);
        }
 
-       /* Send the packet */
+       /* Otherwise, send the packet via UDP */
 
-       struct sockaddr *sa;
-       socklen_t sl;
+       const sockaddr_t *sa;
        int sock;
 
-       sa = &(to->address.sa);
-       sl = SALEN(to->address.sa);
-       sock = to->sock;
+       choose_udp_address(to, &sa, &sock);
 
-       if(sendto(listen_socket[sock].udp, data, len, 0, sa, sl) < 0 && !sockwouldblock(sockerrno)) {
+       if(sendto(listen_socket[sock].udp.fd, data, len, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
                if(sockmsgsize(sockerrno)) {
                        if(to->maxmtu >= len)
                                to->maxmtu = len - 1;
@@ -631,9 +702,11 @@ bool receive_sptps_record(void *handle, uint8_t type, const char *data, uint16_t
        node_t *from = handle;
 
        if(type == SPTPS_HANDSHAKE) {
-               from->status.validkey = true;
-               from->status.waitingforkey = false;
-               logger(DEBUG_META, LOG_INFO, "SPTPS key exchange with %s (%s) succesful", from->name, from->hostname);
+               if(!from->status.validkey) {
+                       from->status.validkey = true;
+                       from->status.waitingforkey = false;
+                       logger(DEBUG_META, LOG_INFO, "SPTPS key exchange with %s (%s) succesful", from->name, from->hostname);
+               }
                return true;
        }
 
@@ -755,7 +828,7 @@ void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
                send_packet(myself, packet);
 
        // In TunnelServer mode, do not forward broadcast packets.
-        // The MST might not be valid and create loops.
+       // The MST might not be valid and create loops.
        if(tunnelserver || broadcast_mode == BMODE_NONE)
                return;
 
@@ -773,7 +846,7 @@ void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
                        break;
 
                // In direct mode, we send copies to each node we know of.
-               // However, this only reaches nodes that can be reached in a single hop.
+               // However, this only reaches nodes that can be reached in a single hop.
                // We don't have enough information to forward broadcast packets in this case.
                case BMODE_DIRECT:
                        if(from != myself)
@@ -793,14 +866,13 @@ static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
        node_t *n = NULL;
        bool hard = false;
        static time_t last_hard_try = 0;
-       time_t now = time(NULL);
 
        for splay_each(edge_t, e, edge_weight_tree) {
                if(!e->to->status.reachable || e->to == myself)
                        continue;
 
                if(sockaddrcmp_noport(from, &e->address)) {
-                       if(last_hard_try == now)
+                       if(last_hard_try == now.tv_sec)
                                continue;
                        hard = true;
                }
@@ -813,13 +885,14 @@ static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
        }
 
        if(hard)
-               last_hard_try = now;
+               last_hard_try = now.tv_sec;
 
-       last_hard_try = now;
+       last_hard_try = now.tv_sec;
        return n;
 }
 
-void handle_incoming_vpn_data(int sock, short events, void *data) {
+void handle_incoming_vpn_data(void *data, int flags) {
+       listen_socket_t *ls = data;
        vpn_packet_t pkt;
        char *hostname;
        sockaddr_t from = {{0}};
@@ -827,7 +900,7 @@ void handle_incoming_vpn_data(int sock, short events, void *data) {
        node_t *n;
        int len;
 
-       len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
+       len = recvfrom(ls->udp.fd, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
 
        if(len <= 0 || len > MAXSIZE) {
                if(!sockwouldblock(sockerrno))
@@ -837,7 +910,7 @@ void handle_incoming_vpn_data(int sock, short events, void *data) {
 
        pkt.len = len;
 
-       sockaddrunmap(&from);           /* Some braindead IPv6 implementations do stupid things. */
+       sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */
 
        n = lookup_node_udp(&from);
 
@@ -855,12 +928,12 @@ void handle_incoming_vpn_data(int sock, short events, void *data) {
                        return;
        }
 
-       n->sock = (intptr_t)data;
+       n->sock = ls - listen_socket;
 
        receive_udppacket(n, &pkt);
 }
 
-void handle_device_data(int sock, short events, void *data) {
+void handle_device_data(void *data, int flags) {
        vpn_packet_t packet;
 
        packet.priority = 0;