/* 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 "conf.h" #include "connection.h" #include "list.h" #include "logger.h" #include "meta.h" #include "names.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(DEBUG_ALWAYS, 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(DEBUG_ALWAYS, LOG_ERR, "ioctlsocket for %s: %s", 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(DEBUG_ALWAYS, LOG_ERR, "Can't bind to interface %s: %s", iface, strerror(errno)); return false; } #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */ logger(DEBUG_ALWAYS, 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) { logger(DEBUG_STATUS, 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(DEBUG_ALWAYS, LOG_ERR, "Can't bind to interface %s: %s", iface, strerror(sockerrno)); return -1; } #else logger(DEBUG_ALWAYS, LOG_WARNING, "%s not supported on this platform", "BindToInterface"); #endif } if(bind(nfd, &sa->sa, SALEN(sa->sa))) { closesocket(nfd); addrstr = sockaddr2hostname(sa); logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno)); free(addrstr); return -1; } if(listen(nfd, 3)) { closesocket(nfd); logger(DEBUG_ALWAYS, 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(DEBUG_ALWAYS, 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(DEBUG_ALWAYS, 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(DEBUG_ALWAYS, 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(DEBUG_ALWAYS, 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(DEBUG_ALWAYS, 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(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno)); free(addrstr); return -1; } return nfd; } /* int setup_vpn_in_socket */ static void retry_outgoing_handler(void *data) { setup_outgoing_connection(data); } void retry_outgoing(outgoing_t *outgoing) { outgoing->timeout += 5; if(outgoing->timeout > maxtimeout) outgoing->timeout = maxtimeout; timeout_add(&outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval){outgoing->timeout, rand() % 100000}); logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout); } 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->status.connecting = false; 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(DEBUG_ALWAYS, LOG_ERR, "Could not create socketpair: %s", strerror(errno)); return; } if(fork()) { c->socket = fd[0]; close(fd[1]); logger(DEBUG_CONNECTIONS, 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(DEBUG_ALWAYS, LOG_ERR, "Could not execute %s: %s", command, strerror(errno)); else if(result) logger(DEBUG_ALWAYS, LOG_ERR, "%s exited with non-zero status %d", command, result); exit(result); #else logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type exec not supported on this platform!"); return; #endif } static void handle_meta_write(connection_t *c) { 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) { 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)); } terminate_connection(c, c->status.active); return; } buffer_read(&c->outbuf, outlen); if(!c->outbuf.len) io_set(&c->io, IO_READ); } static void handle_meta_io(void *data, int flags) { if(flags & IO_WRITE) handle_meta_write(data); else handle_meta_connection_data(data); } bool do_outgoing_connection(outgoing_t *outgoing) { char *address, *port, *space; struct addrinfo *proxyai = NULL; int result; begin: if(!outgoing->ai) { if(!outgoing->cfg) { logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not set up a meta connection to %s", outgoing->name); retry_outgoing(outgoing); return false; } get_config_string(outgoing->cfg, &address); space = strchr(address, ' '); if(space) { port = xstrdup(space + 1); *space = 0; } else { if(!get_config_string(lookup_config(outgoing->config_tree, "Port"), &port)) port = xstrdup("655"); } outgoing->ai = str2addrinfo(address, port, SOCK_STREAM); free(address); free(port); outgoing->aip = outgoing->ai; outgoing->cfg = lookup_config_next(outgoing->config_tree, outgoing->cfg); } if(!outgoing->aip) { if(outgoing->ai) freeaddrinfo(outgoing->ai); outgoing->ai = NULL; goto begin; } connection_t *c = new_connection(); c->outgoing = outgoing; memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen); outgoing->aip = outgoing->aip->ai_next; c->hostname = sockaddr2hostname(&c->address); logger(DEBUG_CONNECTIONS, LOG_INFO, "Trying to connect to %s (%s)", outgoing->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) { free_connection(c); goto begin; } logger(DEBUG_CONNECTIONS, LOG_INFO, "Using proxy at %s port %s", proxyhost, proxyport); c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP); } if(c->socket == -1) { logger(DEBUG_CONNECTIONS, LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno)); free_connection(c); 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 && !sockinprogress(sockerrno)) { logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not connect to %s (%s): %s", outgoing->name, c->hostname, sockstrerror(sockerrno)); free_connection(c); goto begin; } /* Now that there is a working socket, fill in the rest and register this connection. */ c->status.connecting = true; 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; c->last_ping_time = time(NULL); connection_add(c); io_add(&c->io, handle_meta_io, c, c->socket, IO_READ); return true; } void setup_outgoing_connection(outgoing_t *outgoing) { timeout_del(&outgoing->ev); node_t *n = lookup_node(outgoing->name); if(n && n->connection) { logger(DEBUG_CONNECTIONS, LOG_INFO, "Already connected to %s", outgoing->name); n->connection->outgoing = outgoing; return; } init_configuration(&outgoing->config_tree); read_host_config(outgoing->config_tree, outgoing->name); outgoing->cfg = lookup_config(outgoing->config_tree, "Address"); if(!outgoing->cfg) { logger(DEBUG_ALWAYS, LOG_ERR, "No address specified for %s", outgoing->name); return; } do_outgoing_connection(outgoing); } /* accept a new tcp connect and create a new connection */ void handle_new_meta_connection(void *data, int flags) { listen_socket_t *l = data; connection_t *c; sockaddr_t sa; int fd; socklen_t len = sizeof sa; fd = accept(l->tcp.fd, &sa.sa, &len); if(fd < 0) { logger(DEBUG_ALWAYS, LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno)); return; } 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 = time(NULL); logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname); io_add(&c->io, handle_meta_io, c, c->socket, IO_READ); configure_tcp(c); connection_add(c); c->allow_request = ID; send_id(c); } static void free_outgoing(outgoing_t *outgoing) { timeout_del(&outgoing->ev); if(outgoing->ai) freeaddrinfo(outgoing->ai); if(outgoing->config_tree) exit_configuration(&outgoing->config_tree); if(outgoing->name) free(outgoing->name); free(outgoing); } void try_outgoing_connections(void) { /* If there is no outgoing list yet, create one. Otherwise, mark all outgoings as deleted. */ if(!outgoing_list) { outgoing_list = list_alloc((list_action_t)free_outgoing); } else { for list_each(outgoing_t, outgoing, outgoing_list) outgoing->timeout = -1; } /* Make sure there is one outgoing_t in the list for each ConnectTo. */ for(config_t *cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) { char *name; get_config_string(cfg, &name); if(!check_id(name)) { logger(DEBUG_ALWAYS, LOG_ERR, "Invalid name for outgoing connection in %s line %d", cfg->file, cfg->line); free(name); continue; } bool found = false; for list_each(outgoing_t, outgoing, outgoing_list) { if(!strcmp(outgoing->name, name)) { found = true; outgoing->timeout = 0; break; } } if(!found) { outgoing_t *outgoing = xmalloc_and_zero(sizeof *outgoing); outgoing->name = name; list_insert_tail(outgoing_list, outgoing); setup_outgoing_connection(outgoing); } } /* Terminate any connections whose outgoing_t is to be deleted. */ for list_each(connection_t, c, connection_list) { 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); } } /* Delete outgoing_ts for which there is no ConnectTo. */ for list_each(outgoing_t, outgoing, outgoing_list) if(outgoing->timeout == -1) list_delete_node(outgoing_list, node); }