/* net_socket.c -- Handle various kinds of sockets. Copyright (C) 1998-2005 Ivo Timmermans, 2000-2012 Guus Sliepen 2006 Scott Lamb 2009 Florian Forster 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 "avl_tree.h" #include "conf.h" #include "connection.h" #include "event.h" #include "logger.h" #include "meta.h" #include "net.h" #include "netutl.h" #include "protocol.h" #include "utils.h" #include "xalloc.h" /* Needed on Mac OS/X */ #ifndef SOL_TCP #define SOL_TCP IPPROTO_TCP #endif int addressfamily = AF_UNSPEC; int maxtimeout = 900; int seconds_till_retry = 5; int udp_rcvbuf = 0; int udp_sndbuf = 0; listen_socket_t listen_socket[MAXSOCKETS]; int listen_sockets; list_t *outgoing_list = NULL; /* Setup sockets */ static void configure_tcp(connection_t *c) { int option; #ifdef O_NONBLOCK int flags = fcntl(c->socket, F_GETFL); if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) { logger(LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno)); } #elif defined(WIN32) unsigned long arg = 1; if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) { logger(LOG_ERR, "ioctlsocket for %s: %d", c->hostname, sockstrerror(sockerrno)); } #endif #if defined(SOL_TCP) && defined(TCP_NODELAY) option = 1; setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&option, sizeof(option)); #endif #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY) option = IPTOS_LOWDELAY; setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&option, sizeof(option)); #endif } static bool bind_to_interface(int sd) { char *iface; #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) struct ifreq ifr; int status; #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */ if(!get_config_string (lookup_config (config_tree, "BindToInterface"), &iface)) return true; #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) memset(&ifr, 0, sizeof(ifr)); strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ); ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0; status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr)); if(status) { logger(LOG_ERR, "Can't bind to interface %s: %s", iface, strerror(errno)); return false; } #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */ logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface"); #endif return true; } int setup_listen_socket(const sockaddr_t *sa) { int nfd; char *addrstr; int option; char *iface; nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP); if(nfd < 0) { ifdebug(STATUS) logger(LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno)); return -1; } #ifdef FD_CLOEXEC fcntl(nfd, F_SETFD, FD_CLOEXEC); #endif /* Optimize TCP settings */ option = 1; setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option)); #if defined(SOL_IPV6) && defined(IPV6_V6ONLY) if(sa->sa.sa_family == AF_INET6) setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option); #endif if(get_config_string (lookup_config(config_tree, "BindToInterface"), &iface)) { #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) struct ifreq ifr; memset(&ifr, 0, sizeof(ifr)); strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ); if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr))) { closesocket(nfd); logger(LOG_ERR, "Can't bind to interface %s: %s", iface, strerror(sockerrno)); return -1; } #else logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface"); #endif } if(bind(nfd, &sa->sa, SALEN(sa->sa))) { closesocket(nfd); addrstr = sockaddr2hostname(sa); logger(LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno)); free(addrstr); return -1; } if(listen(nfd, 3)) { closesocket(nfd); logger(LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno)); return -1; } return nfd; } int setup_vpn_in_socket(const sockaddr_t *sa) { int nfd; char *addrstr; int option; nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP); if(nfd < 0) { logger(LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno)); return -1; } #ifdef FD_CLOEXEC fcntl(nfd, F_SETFD, FD_CLOEXEC); #endif #ifdef O_NONBLOCK { int flags = fcntl(nfd, F_GETFL); if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) { closesocket(nfd); logger(LOG_ERR, "System call `%s' failed: %s", "fcntl", strerror(errno)); return -1; } } #elif defined(WIN32) { unsigned long arg = 1; if(ioctlsocket(nfd, FIONBIO, &arg) != 0) { closesocket(nfd); logger(LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno)); return -1; } } #endif option = 1; setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option)); 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(LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, strerror(errno)); if(udp_sndbuf && setsockopt(nfd, SOL_SOCKET, SO_SNDBUF, (void *)&udp_sndbuf, sizeof(udp_sndbuf))) logger(LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, strerror(errno)); #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY) if(sa->sa.sa_family == AF_INET6) setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option); #endif #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT) #define IP_DONTFRAGMENT IP_DONTFRAG #endif #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO) if(myself->options & OPTION_PMTU_DISCOVERY) { option = IP_PMTUDISC_DO; setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option)); } #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT) if(myself->options & OPTION_PMTU_DISCOVERY) { 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) if(myself->options & OPTION_PMTU_DISCOVERY) { option = IPV6_PMTUDISC_DO; setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option)); } #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG) if(myself->options & OPTION_PMTU_DISCOVERY) { 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)) { closesocket(nfd); return -1; } if(bind(nfd, &sa->sa, SALEN(sa->sa))) { closesocket(nfd); addrstr = sockaddr2hostname(sa); logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno)); free(addrstr); return -1; } return nfd; } /* int setup_vpn_in_socket */ void retry_outgoing(outgoing_t *outgoing) { outgoing->timeout += 5; if(outgoing->timeout > maxtimeout) outgoing->timeout = maxtimeout; if(outgoing->event) event_del(outgoing->event); outgoing->event = new_event(); outgoing->event->handler = (event_handler_t) setup_outgoing_connection; outgoing->event->time = now + outgoing->timeout; outgoing->event->data = outgoing; event_add(outgoing->event); ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout); } void finish_connecting(connection_t *c) { ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname); if(proxytype != PROXY_EXEC) configure_tcp(c); c->last_ping_time = now; send_id(c); } static void do_outgoing_pipe(connection_t *c, char *command) { #ifndef HAVE_MINGW int fd[2]; if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) { logger(LOG_ERR, "Could not create socketpair: %s\n", strerror(errno)); return; } if(fork()) { c->socket = fd[0]; close(fd[1]); logger(LOG_DEBUG, "Using proxy %s", command); return; } close(0); close(1); close(fd[0]); dup2(fd[1], 0); dup2(fd[1], 1); close(fd[1]); // Other filedescriptors should be closed automatically by CLOEXEC char *host = NULL; char *port = NULL; sockaddr2str(&c->address, &host, &port); setenv("REMOTEADDRESS", host, true); setenv("REMOTEPORT", port, true); setenv("NODE", c->name, true); setenv("NAME", myself->name, true); if(netname) setenv("NETNAME", netname, true); int result = system(command); if(result < 0) logger(LOG_ERR, "Could not execute %s: %s\n", command, strerror(errno)); else if(result) logger(LOG_ERR, "%s exited with non-zero status %d", command, result); exit(result); #else logger(LOG_ERR, "Proxy type exec not supported on this platform!"); return; #endif } void do_outgoing_connection(connection_t *c) { char *address, *port, *space; struct addrinfo *proxyai; int result; if(!c->outgoing) { logger(LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name); abort(); } begin: if(!c->outgoing->ai) { if(!c->outgoing->cfg) { ifdebug(CONNECTIONS) logger(LOG_ERR, "Could not set up a meta connection to %s", c->name); c->status.remove = true; retry_outgoing(c->outgoing); c->outgoing = NULL; return; } get_config_string(c->outgoing->cfg, &address); space = strchr(address, ' '); if(space) { port = xstrdup(space + 1); *space = 0; } else { if(!get_config_string(lookup_config(c->config_tree, "Port"), &port)) port = xstrdup("655"); } c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM); free(address); free(port); c->outgoing->aip = c->outgoing->ai; c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg); } if(!c->outgoing->aip) { if(c->outgoing->ai) freeaddrinfo(c->outgoing->ai); c->outgoing->ai = NULL; goto begin; } memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen); c->outgoing->aip = c->outgoing->aip->ai_next; if(c->hostname) free(c->hostname); c->hostname = sockaddr2hostname(&c->address); ifdebug(CONNECTIONS) logger(LOG_INFO, "Trying to connect to %s (%s)", c->name, c->hostname); if(!proxytype) { c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP); configure_tcp(c); } else if(proxytype == PROXY_EXEC) { do_outgoing_pipe(c, proxyhost); } else { proxyai = str2addrinfo(proxyhost, proxyport, SOCK_STREAM); if(!proxyai) goto begin; ifdebug(CONNECTIONS) logger(LOG_INFO, "Using proxy at %s port %s", proxyhost, proxyport); c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP); } if(c->socket == -1) { ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno)); goto begin; } #ifdef FD_CLOEXEC fcntl(c->socket, F_SETFD, FD_CLOEXEC); #endif if(proxytype != PROXY_EXEC) { #if defined(SOL_IPV6) && defined(IPV6_V6ONLY) int option = 1; if(c->address.sa.sa_family == AF_INET6) setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option); #endif bind_to_interface(c->socket); } /* Connect */ if(!proxytype) { result = connect(c->socket, &c->address.sa, SALEN(c->address.sa)); } else if(proxytype == PROXY_EXEC) { result = 0; } else { result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen); freeaddrinfo(proxyai); } if(result == -1) { if(sockinprogress(sockerrno)) { c->status.connecting = true; return; } closesocket(c->socket); ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno)); goto begin; } finish_connecting(c); return; } void setup_outgoing_connection(outgoing_t *outgoing) { connection_t *c; node_t *n; outgoing->event = NULL; n = lookup_node(outgoing->name); if(n) if(n->connection) { ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name); n->connection->outgoing = outgoing; return; } c = new_connection(); c->name = xstrdup(outgoing->name); c->outcipher = myself->connection->outcipher; c->outdigest = myself->connection->outdigest; c->outmaclength = myself->connection->outmaclength; c->outcompression = myself->connection->outcompression; init_configuration(&c->config_tree); read_connection_config(c); outgoing->cfg = lookup_config(c->config_tree, "Address"); if(!outgoing->cfg) { logger(LOG_ERR, "No address specified for %s", c->name); free_connection(c); return; } c->outgoing = outgoing; c->last_ping_time = now; connection_add(c); do_outgoing_connection(c); } /* accept a new tcp connect and create a new connection */ bool handle_new_meta_connection(int sock) { connection_t *c; sockaddr_t sa; int fd; socklen_t len = sizeof(sa); fd = accept(sock, &sa.sa, &len); if(fd < 0) { logger(LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno)); return false; } sockaddrunmap(&sa); c = new_connection(); c->name = xstrdup(""); c->outcipher = myself->connection->outcipher; c->outdigest = myself->connection->outdigest; c->outmaclength = myself->connection->outmaclength; c->outcompression = myself->connection->outcompression; c->address = sa; c->hostname = sockaddr2hostname(&sa); c->socket = fd; c->last_ping_time = now; ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname); configure_tcp(c); connection_add(c); c->allow_request = ID; send_id(c); return true; } static void free_outgoing(outgoing_t *outgoing) { if(outgoing->ai) freeaddrinfo(outgoing->ai); if(outgoing->name) free(outgoing->name); free(outgoing); } void try_outgoing_connections(void) { static config_t *cfg = NULL; char *name; outgoing_t *outgoing; outgoing_list = list_alloc((list_action_t)free_outgoing); for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) { get_config_string(cfg, &name); if(!check_id(name)) { logger(LOG_ERR, "Invalid name for outgoing connection in %s line %d", cfg->file, cfg->line); free(name); continue; } outgoing = xmalloc_and_zero(sizeof(*outgoing)); outgoing->name = name; list_insert_tail(outgoing_list, outgoing); setup_outgoing_connection(outgoing); } }