list_delete() already free()s the deleted element.
[tinc] / src / net_socket.c
index d5f85d5..767e91e 100644 (file)
@@ -1,7 +1,7 @@
 /*
     net_socket.c -- Handle various kinds of sockets.
     Copyright (C) 1998-2005 Ivo Timmermans,
-                  2000-2013 Guus Sliepen <guus@tinc-vpn.org>
+                  2000-2014 Guus Sliepen <guus@tinc-vpn.org>
                   2006      Scott Lamb <slamb@slamb.org>
                   2009      Florian Forster <octo@verplant.org>
 
@@ -43,8 +43,9 @@
 int addressfamily = AF_UNSPEC;
 int maxtimeout = 900;
 int seconds_till_retry = 5;
-int udp_rcvbuf = 0;
-int udp_sndbuf = 0;
+int udp_rcvbuf = 1024 * 1024;
+int udp_sndbuf = 1024 * 1024;
+int max_connection_burst = 100;
 
 listen_socket_t listen_socket[MAXSOCKETS];
 int listen_sockets;
@@ -102,7 +103,7 @@ static bool bind_to_interface(int sd) {
        status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr));
        if(status) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to interface %s: %s", iface,
-                               strerror(errno));
+                               sockstrerror(sockerrno));
                return false;
        }
 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
@@ -112,6 +113,34 @@ static bool bind_to_interface(int sd) {
        return true;
 }
 
+static bool bind_to_address(connection_t *c) {
+       int s = -1;
+
+       for(int i = 0; i < listen_sockets && listen_socket[i].bindto; i++) {
+               if(listen_socket[i].sa.sa.sa_family != c->address.sa.sa_family)
+                       continue;
+               if(s >= 0)
+                       return false;
+               s = i;
+       }
+
+       if(s < 0)
+               return false;
+
+       sockaddr_t sa = listen_socket[s].sa;
+       if(sa.sa.sa_family == AF_INET)
+               sa.in.sin_port = 0;
+       else if(sa.sa.sa_family == AF_INET6)
+               sa.in6.sin6_port = 0;
+
+       if(bind(c->socket, &sa.sa, SALEN(sa.sa))) {
+               logger(DEBUG_CONNECTIONS, LOG_WARNING, "Can't bind outgoing socket: %s", sockstrerror(sockerrno));
+               return false;
+       }
+
+       return true;
+}
+
 int setup_listen_socket(const sockaddr_t *sa) {
        int nfd;
        char *addrstr;
@@ -150,7 +179,7 @@ int setup_listen_socket(const sockaddr_t *sa) {
                if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof ifr)) {
                        closesocket(nfd);
                        logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to interface %s: %s", iface,
-                                  strerror(sockerrno));
+                                  sockstrerror(sockerrno));
                        return -1;
                }
 #else
@@ -218,10 +247,10 @@ int setup_vpn_in_socket(const sockaddr_t *sa) {
        setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof option);
 
        if(udp_rcvbuf && setsockopt(nfd, SOL_SOCKET, SO_RCVBUF, (void *)&udp_rcvbuf, sizeof(udp_rcvbuf)))
-               logger(DEBUG_ALWAYS, LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, strerror(errno));
+               logger(DEBUG_ALWAYS, LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, sockstrerror(sockerrno));
 
        if(udp_sndbuf && setsockopt(nfd, SOL_SOCKET, SO_SNDBUF, (void *)&udp_sndbuf, sizeof(udp_sndbuf)))
-               logger(DEBUG_ALWAYS, LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, strerror(errno));
+               logger(DEBUG_ALWAYS, LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, sockstrerror(sockerrno));
 
 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
        if(sa->sa.sa_family == AF_INET6)
@@ -242,8 +271,6 @@ int setup_vpn_in_socket(const sockaddr_t *sa) {
                option = 1;
                setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
        }
-#else
-#warning No way to disable IPv4 fragmentation
 #endif
 
 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
@@ -256,8 +283,6 @@ int setup_vpn_in_socket(const sockaddr_t *sa) {
                option = 1;
                setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
        }
-#else
-#warning No way to disable IPv6 fragmentation
 #endif
 
        if (!bind_to_interface(nfd)) {
@@ -294,10 +319,7 @@ void retry_outgoing(outgoing_t *outgoing) {
 void finish_connecting(connection_t *c) {
        logger(DEBUG_CONNECTIONS, LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 
-       if(proxytype != PROXY_EXEC)
-               configure_tcp(c);
-
-       c->last_ping_time = time(NULL);
+       c->last_ping_time = now.tv_sec;
        c->status.connecting = false;
 
        send_id(c);
@@ -308,7 +330,7 @@ static void do_outgoing_pipe(connection_t *c, char *command) {
        int fd[2];
 
        if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
-               logger(DEBUG_ALWAYS, LOG_ERR, "Could not create socketpair: %s", strerror(errno));
+               logger(DEBUG_ALWAYS, LOG_ERR, "Could not create socketpair: %s", sockstrerror(sockerrno));
                return;
        }
 
@@ -352,18 +374,21 @@ static void do_outgoing_pipe(connection_t *c, char *command) {
 }
 
 static void handle_meta_write(connection_t *c) {
+       if(c->outbuf.len <= c->outbuf.offset)
+               return;
+
        ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, 0);
        if(outlen <= 0) {
-               if(!errno || errno == EPIPE) {
+               if(!sockerrno || sockerrno == EPIPE) {
                        logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection closed by %s (%s)", c->name, c->hostname);
                } else if(sockwouldblock(sockerrno)) {
                        logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Sending %d bytes to %s (%s) would block", c->outbuf.len - c->outbuf.offset, c->name, c->hostname);
                        return;
                } else {
-                       logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not send %d bytes of data to %s (%s): %s", c->outbuf.len - c->outbuf.offset, c->name, c->hostname, strerror(errno));
+                       logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not send %d bytes of data to %s (%s): %s", c->outbuf.len - c->outbuf.offset, c->name, c->hostname, sockstrerror(sockerrno));
                }
 
-               terminate_connection(c, c->status.active);
+               terminate_connection(c, c->edge);
                return;
        }
 
@@ -373,10 +398,47 @@ static void handle_meta_write(connection_t *c) {
 }
 
 static void handle_meta_io(void *data, int flags) {
+       connection_t *c = data;
+
+       if(c->status.connecting) {
+               /*
+                  The event loop does not protect against spurious events. Verify that we are actually connected
+                  by issuing an empty send() call.
+
+                  Note that the behavior of send() on potentially unconnected sockets differ between platforms:
+                  +------------+-----------+-------------+-----------+
+                  |   Event    |   POSIX   |    Linux    |  Windows  |
+                  +------------+-----------+-------------+-----------+
+                  | Spurious   | ENOTCONN  | EWOULDBLOCK | ENOTCONN  |
+                  | Failed     | ENOTCONN  | (cause)     | ENOTCONN  |
+                  | Successful | (success) | (success)   | (success) |
+                  +------------+-----------+-------------+-----------+
+               */
+               if (send(c->socket, NULL, 0, 0) != 0) {
+                       if (sockwouldblock(sockerrno))
+                               return;
+                       int socket_error;
+                       if (!socknotconn(sockerrno))
+                               socket_error = sockerrno;
+                       else {
+                               socklen_t len = sizeof socket_error;
+                               getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&socket_error, &len);
+                       }
+                       if (socket_error) {
+                               logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while connecting to %s (%s): %s", c->name, c->hostname, sockstrerror(socket_error));
+                               terminate_connection(c, false);
+                       }
+                       return;
+               }
+
+               c->status.connecting = false;
+               finish_connecting(c);
+       }
+
        if(flags & IO_WRITE)
-               handle_meta_write(data);
+               handle_meta_write(c);
        else
-               handle_meta_connection_data(data);
+               handle_meta_connection_data(c);
 }
 
 bool do_outgoing_connection(outgoing_t *outgoing) {
@@ -441,6 +503,7 @@ begin:
                }
                logger(DEBUG_CONNECTIONS, LOG_INFO, "Using proxy at %s port %s", proxyhost, proxyport);
                c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
+               configure_tcp(c);
        }
 
        if(c->socket == -1) {
@@ -461,6 +524,7 @@ begin:
 #endif
 
                bind_to_interface(c->socket);
+               bind_to_address(c);
        }
 
        /* Connect */
@@ -485,19 +549,54 @@ begin:
 
        c->status.connecting = true;
        c->name = xstrdup(outgoing->name);
+#ifndef DISABLE_LEGACY
        c->outcipher = myself->connection->outcipher;
        c->outdigest = myself->connection->outdigest;
+#endif
        c->outmaclength = myself->connection->outmaclength;
        c->outcompression = myself->connection->outcompression;
-       c->last_ping_time = time(NULL);
+       c->last_ping_time = now.tv_sec;
 
        connection_add(c);
 
-       io_add(&c->io, handle_meta_io, c, c->socket, IO_READ);
+       io_add(&c->io, handle_meta_io, c, c->socket, IO_READ|IO_WRITE);
 
        return true;
 }
 
+// Find edges pointing to this node, and use them to build a list of unique, known addresses.
+static struct addrinfo *get_known_addresses(node_t *n) {
+       struct addrinfo *ai = NULL;
+
+       for splay_each(edge_t, e, n->edge_tree) {
+               if(!e->reverse)
+                       continue;
+
+               bool found = false;
+               for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
+                       if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
+                               found = true;
+                               break;
+                       }
+               }
+               if(found)
+                       continue;
+
+               struct addrinfo *nai = xzalloc(sizeof *nai);
+               if(ai)
+                       ai->ai_next = nai;
+               ai = nai;
+               ai->ai_family = e->reverse->address.sa.sa_family;
+               ai->ai_socktype = SOCK_STREAM;
+               ai->ai_protocol = IPPROTO_TCP;
+               ai->ai_addrlen = SALEN(e->reverse->address.sa);
+               ai->ai_addr = xmalloc(ai->ai_addrlen);
+               memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
+       }
+
+       return ai;
+}
+
 void setup_outgoing_connection(outgoing_t *outgoing) {
        timeout_del(&outgoing->ev);
 
@@ -505,9 +604,12 @@ void setup_outgoing_connection(outgoing_t *outgoing) {
 
        if(n && n->connection) {
                logger(DEBUG_CONNECTIONS, LOG_INFO, "Already connected to %s", outgoing->name);
-
-               n->connection->outgoing = outgoing;
-               return;
+               if(!n->connection->outgoing) {
+                       n->connection->outgoing = outgoing;
+                       return;
+               } else {
+                       goto remove;
+               }
        }
 
        init_configuration(&outgoing->config_tree);
@@ -515,11 +617,19 @@ void setup_outgoing_connection(outgoing_t *outgoing) {
        outgoing->cfg = lookup_config(outgoing->config_tree, "Address");
 
        if(!outgoing->cfg) {
-               logger(DEBUG_ALWAYS, LOG_ERR, "No address specified for %s", outgoing->name);
-               return;
+               if(n)
+                       outgoing->aip = outgoing->ai = get_known_addresses(n);
+               if(!outgoing->ai) {
+                       logger(DEBUG_ALWAYS, LOG_DEBUG, "No address known for %s", outgoing->name);
+                       goto remove;
+               }
        }
 
        do_outgoing_connection(outgoing);
+       return;
+
+remove:
+       list_delete(outgoing_list, outgoing);
 }
 
 /*
@@ -542,17 +652,70 @@ void handle_new_meta_connection(void *data, int flags) {
 
        sockaddrunmap(&sa);
 
+       // Check if we get many connections from the same host
+
+       static sockaddr_t prev_sa;
+       static int tarpit = -1;
+
+       if(tarpit >= 0) {
+               closesocket(tarpit);
+               tarpit = -1;
+       }
+
+       if(!sockaddrcmp_noport(&sa, &prev_sa)) {
+               static int samehost_burst;
+               static int samehost_burst_time;
+
+               if(now.tv_sec - samehost_burst_time > samehost_burst)
+                       samehost_burst = 0;
+               else
+                       samehost_burst -= now.tv_sec - samehost_burst_time;
+
+               samehost_burst_time = now.tv_sec;
+               samehost_burst++;
+
+               if(samehost_burst > max_connection_burst) {
+                       tarpit = fd;
+                       return;
+               }
+       }
+
+       memcpy(&prev_sa, &sa, sizeof sa);
+
+       // Check if we get many connections from different hosts
+
+       static int connection_burst;
+       static int connection_burst_time;
+
+       if(now.tv_sec - connection_burst_time > connection_burst)
+               connection_burst = 0;
+       else
+               connection_burst -= now.tv_sec - connection_burst_time;
+
+       connection_burst_time = now.tv_sec;
+       connection_burst++;
+
+       if(connection_burst >= max_connection_burst) {
+               connection_burst = max_connection_burst;
+               tarpit = fd;
+               return;
+       }
+
+       // Accept the new connection
+
        c = new_connection();
        c->name = xstrdup("<unknown>");
+#ifndef DISABLE_LEGACY
        c->outcipher = myself->connection->outcipher;
        c->outdigest = myself->connection->outdigest;
+#endif
        c->outmaclength = myself->connection->outmaclength;
        c->outcompression = myself->connection->outcompression;
 
        c->address = sa;
        c->hostname = sockaddr2hostname(&sa);
        c->socket = fd;
-       c->last_ping_time = time(NULL);
+       c->last_ping_time = now.tv_sec;
 
        logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
 
@@ -591,7 +754,7 @@ void handle_new_unix_connection(void *data, int flags) {
        c->address = sa;
        c->hostname = xstrdup("localhost port unix");
        c->socket = fd;
-       c->last_ping_time = time(NULL);
+       c->last_ping_time = now.tv_sec;
 
        logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
 
@@ -644,6 +807,11 @@ void try_outgoing_connections(void) {
                        continue;
                }
 
+               if(!strcmp(name, myself->name)) {
+                       free(name);
+                       continue;
+               }
+
                bool found = false;
 
                for list_each(outgoing_t, outgoing, outgoing_list) {
@@ -655,7 +823,7 @@ void try_outgoing_connections(void) {
                }
 
                if(!found) {
-                       outgoing_t *outgoing = xmalloc_and_zero(sizeof *outgoing);
+                       outgoing_t *outgoing = xzalloc(sizeof *outgoing);
                        outgoing->name = name;
                        list_insert_tail(outgoing_list, outgoing);
                        setup_outgoing_connection(outgoing);
@@ -668,7 +836,7 @@ void try_outgoing_connections(void) {
                if(c->outgoing && c->outgoing->timeout == -1) {
                        c->outgoing = NULL;
                        logger(DEBUG_CONNECTIONS, LOG_INFO, "No more outgoing connection to %s", c->name);
-                       terminate_connection(c, c->status.active);
+                       terminate_connection(c, c->edge);
                }
        }