/* net.c -- most of the network code Copyright (C) 1998-2001 Ivo Timmermans , 2000,2001 Guus Sliepen 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., 675 Mass Ave, Cambridge, MA 02139, USA. $Id: net.c,v 1.35.4.151 2001/11/16 22:41:38 zarq Exp $ */ #include "config.h" #include #include #include #include #ifdef HAVE_LINUX #include #include #endif #include #include #include #include #include #include #include #include #include #include /* SunOS really wants sys/socket.h BEFORE net/if.h, and FreeBSD wants these lines below the rest. */ #include #include #include #include #include #include #ifndef HAVE_RAND_PSEUDO_BYTES #define RAND_pseudo_bytes RAND_bytes #endif #include #include #include #include #include "conf.h" #include "connection.h" #include "meta.h" #include "net.h" #include "process.h" #include "protocol.h" #include "subnet.h" #include "process.h" #include "route.h" #include "device.h" #include "system.h" int maxtimeout = 900; int seconds_till_retry = 5; int tcp_socket = -1; int udp_socket = -1; int keylifetime = 0; int keyexpires = 0; int do_prune = 0; /* VPN packet I/O */ char *hostlookup(struct sockaddr *addr, int numericonly) { char *hostname; int flags = 0; int r; cp if(numericonly || (get_config_bool(lookup_config(config_tree, "ResolveDNS"), &r) || !r )) flags |= NI_NUMERICHOST; hostname = xmalloc(NI_MAXHOST); if((r = getnameinfo(addr, sizeof(*addr), hostname, NI_MAXHOST, NULL, 0, flags)) != 0) { free(hostname); if(flags & NI_NUMERICHOST) { syslog(LOG_ERR, _("Address conversion failed: %s"), gai_strerror(r)); return NULL; } else return hostlookup(addr, 1); } cp return hostname; } void receive_udppacket(node_t *n, vpn_packet_t *inpkt) { vpn_packet_t outpkt; int outlen, outpad; EVP_CIPHER_CTX ctx; cp /* Decrypt the packet */ EVP_DecryptInit(&ctx, myself->cipher, myself->key, myself->key + myself->cipher->key_len); EVP_DecryptUpdate(&ctx, outpkt.salt, &outlen, inpkt->salt, inpkt->len); EVP_DecryptFinal(&ctx, outpkt.salt + outlen, &outpad); outlen += outpad; outpkt.len = outlen - sizeof(outpkt.salt); receive_packet(n, &outpkt); cp } void receive_tcppacket(connection_t *c, char *buffer, int len) { vpn_packet_t outpkt; cp outpkt.len = len; memcpy(outpkt.data, buffer, len); receive_packet(c->node, &outpkt); cp } void receive_packet(node_t *n, vpn_packet_t *packet) { cp if(debug_lvl >= DEBUG_TRAFFIC) syslog(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"), packet->len, n->name, n->hostname); route_incoming(n, packet); cp } void send_udppacket(node_t *n, vpn_packet_t *inpkt) { vpn_packet_t outpkt; int outlen, outpad; EVP_CIPHER_CTX ctx; vpn_packet_t *copy; cp if(!n->status.validkey) { if(debug_lvl >= DEBUG_TRAFFIC) syslog(LOG_INFO, _("No valid key known yet for %s (%s), queueing packet"), n->name, n->hostname); /* Since packet is on the stack of handle_tap_input(), we have to make a copy of it first. */ copy = xmalloc(sizeof(vpn_packet_t)); memcpy(copy, inpkt, sizeof(vpn_packet_t)); list_insert_tail(n->queue, copy); if(!n->status.waitingforkey) send_req_key(n->nexthop->connection, myself, n); return; } /* Encrypt the packet. */ RAND_pseudo_bytes(inpkt->salt, sizeof(inpkt->salt)); EVP_EncryptInit(&ctx, n->cipher, n->key, n->key + n->cipher->key_len); EVP_EncryptUpdate(&ctx, outpkt.salt, &outlen, inpkt->salt, inpkt->len + sizeof(inpkt->salt)); EVP_EncryptFinal(&ctx, outpkt.salt + outlen, &outpad); outlen += outpad; if((sendto(udp_socket, (char *) outpkt.salt, outlen, 0, n->address->ai_addr, n->address->ai_addrlen)) < 0) { syslog(LOG_ERR, _("Error sending packet to %s (%s): %m"), n->name, n->hostname); return; } cp } /* send a packet to the given vpn ip. */ void send_packet(node_t *n, vpn_packet_t *packet) { cp if(debug_lvl >= DEBUG_TRAFFIC) syslog(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"), packet->len, n->name, n->hostname); if(n == myself) { if(debug_lvl >= DEBUG_TRAFFIC) { syslog(LOG_NOTICE, _("Packet is looping back to us!")); } return; } if(n->via != n && debug_lvl >= DEBUG_TRAFFIC) syslog(LOG_ERR, _("Sending packet to %s via %s (%s)"), n->name, n->via->name, n->via->hostname); if((myself->options | n->via->options) & OPTION_TCPONLY) { if(send_tcppacket(n->via->connection, packet)) terminate_connection(n->via->connection, 1); } else send_udppacket(n->via, packet); } /* Broadcast a packet to all active direct connections */ void broadcast_packet(node_t *from, vpn_packet_t *packet) { avl_node_t *node; connection_t *c; cp if(debug_lvl >= DEBUG_TRAFFIC) syslog(LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"), packet->len, from->name, from->hostname); for(node = connection_tree->head; node; node = node->next) { c = (connection_t *)node->data; if(c->status.active && c != from->nexthop->connection) send_packet(c->node, packet); } cp } void flush_queue(node_t *n) { list_node_t *node, *next; cp if(debug_lvl >= DEBUG_TRAFFIC) syslog(LOG_INFO, _("Flushing queue for %s (%s)"), n->name, n->hostname); for(node = n->queue->head; node; node = next) { next = node->next; send_udppacket(n, (vpn_packet_t *)node->data); list_delete_node(n->queue, node); } cp } /* Setup sockets */ int setup_listen_socket(node_t *n) { int nfd, flags; int option; char *address; int r; struct addrinfo hints, *ai, *aitop; int ipv6preferred; #ifdef HAVE_LINUX char *interface; #endif cp if(!get_config_string(lookup_config(config_tree, "BindToAddress"), &address)) { address = NULL; } hints.ai_socktype = SOCK_STREAM; hints.ai_protocol = IPPROTO_TCP; hints.ai_family = AF_INET; if(get_config_bool(lookup_config(config_tree, "IPv6Preferred"), &ipv6preferred)) { if(ipv6preferred) hints.ai_family = PF_UNSPEC; } if((r = getaddrinfo(address, n->port, &hints, &aitop)) != 0) { syslog(LOG_ERR, _("Looking up `%s' failed: %s\n"), address, gai_strerror(r)); return -1; } /* Try to create a listening socket for all alternatives we got from getaddrinfo. */ for(ai = aitop; ai != NULL; ai = ai->ai_next) { if((nfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol)) < 0) { syslog(LOG_ERR, _("Creating metasocket failed: %m")); continue; } flags = fcntl(nfd, F_GETFL); if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) { close(nfd); syslog(LOG_ERR, _("System call `%s' failed: %m"), "fcntl"); continue; } /* Optimize TCP settings */ option = 1; setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option)); setsockopt(nfd, SOL_SOCKET, SO_KEEPALIVE, &option, sizeof(option)); #ifdef HAVE_LINUX setsockopt(nfd, SOL_TCP, TCP_NODELAY, &option, sizeof(option)); option = IPTOS_LOWDELAY; setsockopt(nfd, SOL_IP, IP_TOS, &option, sizeof(option)); if(get_config_string(lookup_config(config_tree, "BindToInterface"), &interface)) if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, interface, strlen(interface))) { close(nfd); syslog(LOG_ERR, _("Can't bind to interface %s: %m"), interface); continue; } #endif if(bind(nfd, ai->ai_addr, ai->ai_addrlen)) { close(nfd); syslog(LOG_ERR, _("Can't bind to %s port %s/tcp: %m"), ai->ai_canonname, n->port); continue; } if(listen(nfd, 3)) { close(nfd); syslog(LOG_ERR, _("System call `%s' failed: %m"), "listen"); continue; } break; /* We have successfully bound to a socket */ } if(ai == NULL) /* None of the alternatives succeeded */ { syslog(LOG_ERR, _("Failed to open a listening socket.")); return -1; } cp return nfd; } int setup_vpn_in_socket(node_t *n) { const int one = 1; int nfd, flags; int option; char *address; int r; struct addrinfo hints, *ai, *aitop; int ipv6preferred; #ifdef HAVE_LINUX char *interface; #endif cp if(!get_config_string(lookup_config(config_tree, "BindToAddress"), &address)) { address = NULL; } hints.ai_socktype = SOCK_DGRAM; hints.ai_protocol = IPPROTO_UDP; hints.ai_family = AF_INET; if(get_config_bool(lookup_config(config_tree, "IPv6Preferred"), &ipv6preferred)) { if(ipv6preferred) hints.ai_family = PF_UNSPEC; } if((r = getaddrinfo(address, n->port, &hints, &aitop)) != 0) { syslog(LOG_ERR, _("Looking up `%s' failed: %s\n"), address, gai_strerror(r)); return -1; } setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); /* Try to create a listening socket for all alternatives we got from getaddrinfo. */ for(ai = aitop; ai != NULL; ai = ai->ai_next) { if((nfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol)) < 0) { syslog(LOG_ERR, _("Creating metasocket failed: %m")); continue; } flags = fcntl(nfd, F_GETFL); if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) { close(nfd); syslog(LOG_ERR, _("System call `%s' failed: %m"), "fcntl"); continue; } /* Optimize UDP settings */ option = 1; setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option)); #ifdef HAVE_LINUX if(get_config_string(lookup_config(config_tree, "BindToInterface"), &interface)) if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, interface, strlen(interface))) { close(nfd); syslog(LOG_ERR, _("Can't bind to interface %s: %m"), interface); continue; } #endif if(bind(nfd, ai->ai_addr, ai->ai_addrlen)) { close(nfd); syslog(LOG_ERR, _("Can't bind to %s port %s/tcp: %m"), ai->ai_canonname, n->port); continue; } break; /* We have successfully bound to a socket */ } if(ai == NULL) /* None of the alternatives succeeded */ { syslog(LOG_ERR, _("Failed to open a listening socket.")); return -1; } cp return nfd; } int setup_outgoing_socket(connection_t *c) { int flags; cp if(debug_lvl >= DEBUG_CONNECTIONS) syslog(LOG_INFO, _("Trying to connect to %s (%s)"), c->name, c->hostname); c->socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); if(c->socket == -1) { syslog(LOG_ERR, _("Creating socket for %s port %s failed: %m"), c->hostname, c->port); return -1; } /* Bind first to get a fix on our source port??? a.sin_family = AF_INET; a.sin_port = htons(0); a.sin_addr.s_addr = htonl(INADDR_ANY); if(bind(c->socket, (struct sockaddr *)&a, sizeof(struct sockaddr))) { close(c->socket); syslog(LOG_ERR, _("System call `%s' failed: %m"), "bind"); return -1; } */ /* Optimize TCP settings? option = 1; setsockopt(c->socket, SOL_SOCKET, SO_KEEPALIVE, &option, sizeof(option)); #ifdef HAVE_LINUX setsockopt(c->socket, SOL_TCP, TCP_NODELAY, &option, sizeof(option)); option = IPTOS_LOWDELAY; setsockopt(c->socket, SOL_IP, IP_TOS, &option, sizeof(option)); #endif */ /* Connect */ if(connect(c->socket, c->address->ai_addr, c->address->ai_addrlen) == -1) { close(c->socket); syslog(LOG_ERR, _("%s port %s: %m"), c->hostname, c->port); return -1; } flags = fcntl(c->socket, F_GETFL); if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) { close(c->socket); syslog(LOG_ERR, _("fcntl for %s port %s: %m"), c->hostname, c->port); return -1; } if(debug_lvl >= DEBUG_CONNECTIONS) syslog(LOG_INFO, _("Connected to %s port %s"), c->hostname, c->port); cp return 0; } int setup_outgoing_connection(char *name) { connection_t *c; node_t *n; struct addrinfo *ai, *aitop, hints; int r, ipv6preferred; cp n = lookup_node(name); if(n) if(n->connection) { if(debug_lvl >= DEBUG_CONNECTIONS) syslog(LOG_INFO, _("Already connected to %s"), name); return 0; } c = new_connection(); c->name = xstrdup(name); init_configuration(&c->config_tree); read_connection_config(c); if(!get_config_string(lookup_config(c->config_tree, "Address"), &c->hostname)) { syslog(LOG_ERR, _("No address specified for %s"), c->name); free_connection(c); return -1; } if(!get_config_string(lookup_config(c->config_tree, "Port"), &c->port)) { syslog(LOG_ERR, _("No port specified for %s"), c->name); free_connection(c); return -1; } hints.ai_socktype = SOCK_STREAM; hints.ai_family = AF_INET; if(get_config_bool(lookup_config(c->config_tree, "IPv6Preferred"), &ipv6preferred)) { if(ipv6preferred) hints.ai_family = PF_UNSPEC; } if((r = getaddrinfo(c->hostname, c->port, &hints, &aitop)) != 0) { syslog(LOG_ERR, _("Looking up %s failed: %s\n"), c->hostname, gai_strerror(r)); return -1; } for(ai = aitop; ai != NULL; ai = ai->ai_next) { if(setup_outgoing_socket(c) < 0) continue; } if(ai == NULL) { /* No connection alternative succeeded */ free_connection(c); return -1; } c->status.outgoing = 1; c->last_ping_time = time(NULL); connection_add(c); send_id(c); cp return 0; } int read_rsa_public_key(connection_t *c) { FILE *fp; char *fname; char *key; cp if(!c->rsa_key) c->rsa_key = RSA_new(); /* First, check for simple PublicKey statement */ if(get_config_string(lookup_config(c->config_tree, "PublicKey"), &key)) { BN_hex2bn(&c->rsa_key->n, key); BN_hex2bn(&c->rsa_key->e, "FFFF"); return 0; } /* Else, check for PublicKeyFile statement and read it */ if(get_config_string(lookup_config(c->config_tree, "PublicKeyFile"), &fname)) { if(is_safe_path(fname)) { if((fp = fopen(fname, "r")) == NULL) { syslog(LOG_ERR, _("Error reading RSA public key file `%s': %m"), fname); return -1; } c->rsa_key = PEM_read_RSAPublicKey(fp, &c->rsa_key, NULL, NULL); fclose(fp); if(!c->rsa_key) { syslog(LOG_ERR, _("Reading RSA public key file `%s' failed: %m"), fname); return -1; } return 0; } else return -1; } /* Else, check if a harnessed public key is in the config file */ asprintf(&fname, "%s/hosts/%s", confbase, c->name); if((fp = fopen(fname, "r"))) { c->rsa_key = PEM_read_RSAPublicKey(fp, &c->rsa_key, NULL, NULL); fclose(fp); } free(fname); if(c->rsa_key) return 0; else { syslog(LOG_ERR, _("No public key for %s specified!"), c->name); return -1; } } int read_rsa_private_key(void) { FILE *fp; char *fname, *key; cp if(get_config_string(lookup_config(config_tree, "PrivateKey"), &key)) { myself->connection->rsa_key = RSA_new(); BN_hex2bn(&myself->connection->rsa_key->d, key); BN_hex2bn(&myself->connection->rsa_key->e, "FFFF"); } else if(get_config_string(lookup_config(config_tree, "PrivateKeyFile"), &fname)) { if((fp = fopen(fname, "r")) == NULL) { syslog(LOG_ERR, _("Error reading RSA private key file `%s': %m"), fname); return -1; } myself->connection->rsa_key = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL); fclose(fp); if(!myself->connection->rsa_key) { syslog(LOG_ERR, _("Reading RSA private key file `%s' failed: %m"), fname); return -1; } } else { syslog(LOG_ERR, _("No private key for tinc daemon specified!")); return -1; } cp return 0; } /* Configure node_t myself and set up the local sockets (listen only) */ int setup_myself(void) { config_t *cfg; subnet_t *subnet; char *name, *mode; int choice; cp myself = new_node(); myself->connection = new_connection(); init_configuration(&myself->connection->config_tree); asprintf(&myself->hostname, _("MYSELF")); asprintf(&myself->connection->hostname, _("MYSELF")); myself->connection->options = 0; myself->connection->protocol_version = PROT_CURRENT; if(!get_config_string(lookup_config(config_tree, "Name"), &name)) /* Not acceptable */ { syslog(LOG_ERR, _("Name for tinc daemon required!")); return -1; } if(check_id(name)) { syslog(LOG_ERR, _("Invalid name for myself!")); free(name); return -1; } myself->name = name; myself->connection->name = xstrdup(name); cp if(read_rsa_private_key()) return -1; if(read_connection_config(myself->connection)) { syslog(LOG_ERR, _("Cannot open host configuration file for myself!")); return -1; } if(read_rsa_public_key(myself->connection)) return -1; cp /* if(RSA_check_key(rsa_key) != 1) { syslog(LOG_ERR, _("Invalid public/private keypair!")); return -1; } */ if(!get_config_string(lookup_config(myself->connection->config_tree, "Port"), &myself->port)) myself->port = "655"; myself->connection->port = myself->port; /* Read in all the subnets specified in the host configuration file */ cfg = lookup_config(myself->connection->config_tree, "Subnet"); while(cfg) { if(!get_config_subnet(cfg, &subnet)) return -1; subnet_add(myself, subnet); cfg = lookup_config_next(myself->connection->config_tree, cfg); } cp /* Check some options */ if(get_config_bool(lookup_config(config_tree, "IndirectData"), &choice)) if(choice) myself->options |= OPTION_INDIRECT; if(get_config_bool(lookup_config(config_tree, "TCPOnly"), &choice)) if(choice) myself->options |= OPTION_TCPONLY; if(get_config_bool(lookup_config(myself->connection->config_tree, "IndirectData"), &choice)) if(choice) myself->options |= OPTION_INDIRECT; if(get_config_bool(lookup_config(myself->connection->config_tree, "TCPOnly"), &choice)) if(choice) myself->options |= OPTION_TCPONLY; if(myself->options & OPTION_TCPONLY) myself->options |= OPTION_INDIRECT; if(get_config_string(lookup_config(config_tree, "Mode"), &mode)) { if(!strcasecmp(mode, "router")) routing_mode = RMODE_ROUTER; else if (!strcasecmp(mode, "switch")) routing_mode = RMODE_SWITCH; else if (!strcasecmp(mode, "hub")) routing_mode = RMODE_HUB; else { syslog(LOG_ERR, _("Invalid routing mode!")); return -1; } } else routing_mode = RMODE_ROUTER; cp /* Open sockets */ if((tcp_socket = setup_listen_socket(myself)) < 0) { syslog(LOG_ERR, _("Unable to set up a listening TCP socket!")); return -1; } if((udp_socket = setup_vpn_in_socket(myself)) < 0) { syslog(LOG_ERR, _("Unable to set up a listening UDP socket!")); return -1; } cp /* Generate packet encryption key */ myself->cipher = EVP_bf_cbc(); myself->keylength = myself->cipher->key_len + myself->cipher->iv_len; myself->key = (char *)xmalloc(myself->keylength); RAND_pseudo_bytes(myself->key, myself->keylength); if(!get_config_int(lookup_config(config_tree, "KeyExpire"), &keylifetime)) keylifetime = 3600; keyexpires = time(NULL) + keylifetime; cp /* Done */ myself->nexthop = myself; myself->via = myself; myself->status.active = 1; node_add(myself); syslog(LOG_NOTICE, _("Ready: listening on port %s"), myself->port); cp return 0; } /* setup all initial network connections */ int setup_network_connections(void) { cp init_connections(); init_subnets(); init_nodes(); init_edges(); if(get_config_int(lookup_config(config_tree, "PingTimeout"), &timeout)) { if(timeout < 1) { timeout = 86400; } } else timeout = 60; if(setup_device() < 0) return -1; /* Run tinc-up script to further initialize the tap interface */ execute_script("tinc-up"); if(setup_myself() < 0) return -1; signal(SIGALRM, try_outgoing_connections); alarm(5); cp return 0; } /* close all open network connections */ void close_network_connections(void) { avl_node_t *node, *next; connection_t *c; cp for(node = connection_tree->head; node; node = next) { next = node->next; c = (connection_t *)node->data; c->status.outgoing = 0; terminate_connection(c, 0); } terminate_connection(myself->connection, 0); close(udp_socket); close(tcp_socket); exit_edges(); exit_subnets(); exit_nodes(); exit_connections(); execute_script("tinc-down"); close_device(); cp return; } /* handle an incoming tcp connect call and open a connection to it. */ connection_t *create_new_connection(int sfd) { connection_t *c; struct sockaddr_in ci; int len = sizeof(ci); cp c = new_connection(); if(getpeername(sfd, (struct sockaddr *) &ci, (socklen_t *) &len) < 0) { syslog(LOG_ERR, _("System call `%s' failed: %m"), "getpeername"); close(sfd); return NULL; } c->address = sockaddr_to_addrinfo(ci); c->hostname = xmalloc(INET6_ADDRSTRLEN); if((inet_ntop(ci.sin_family, &(ci.sin_addr), c->hostname, INET6_ADDRSTRLEN)) == NULL) { syslog(LOG_ERR, _("Couldn't convert address to string: %m")); free(c->hostname); return NULL; } asprintf(&(c->port), "%d", htons(ci.sin_port)); c->socket = sfd; c->last_ping_time = time(NULL); if(debug_lvl >= DEBUG_CONNECTIONS) syslog(LOG_NOTICE, _("Connection from %s port %s"), c->hostname, c->port); c->allow_request = ID; cp return c; } /* put all file descriptors in an fd_set array */ void build_fdset(fd_set *fs) { avl_node_t *node; connection_t *c; cp FD_ZERO(fs); for(node = connection_tree->head; node; node = node->next) { c = (connection_t *)node->data; FD_SET(c->socket, fs); } FD_SET(tcp_socket, fs); FD_SET(udp_socket, fs); FD_SET(device_fd, fs); cp } /* receive incoming data from the listening udp socket and write it to the ethertap device after being decrypted */ void handle_incoming_vpn_data(void) { vpn_packet_t pkt; int x, l = sizeof(x); struct sockaddr_in from; socklen_t fromlen = sizeof(from); node_t *n; cp if(getsockopt(udp_socket, SOL_SOCKET, SO_ERROR, &x, &l) < 0) { syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%m"), __FILE__, __LINE__, udp_socket); return; } if(x) { syslog(LOG_ERR, _("Incoming data socket error: %s"), strerror(x)); return; } if((pkt.len = recvfrom(udp_socket, (char *) pkt.salt, MTU, 0, (struct sockaddr *)&from, &fromlen)) <= 0) { syslog(LOG_ERR, _("Receiving packet failed: %m")); return; } n = lookup_node_udp(sockaddr_to_addrinfo(&from)); if(!n) { syslog(LOG_WARNING, _("Received UDP packet on port %s from unknown source %x:%hd"), myself->port, ntohl(from.sin_addr.s_addr), ntohs(from.sin_port)); return; } /* if(n->connection) n->connection->last_ping_time = time(NULL); */ receive_udppacket(n, &pkt); cp } /* Terminate a connection: - Close the socket - Remove associated edge and tell other connections about it if report = 1 - Check if we need to retry making an outgoing connection - Deactivate the host */ void terminate_connection(connection_t *c, int report) { avl_node_t *node; connection_t *other; cp if(c->status.remove) return; if(debug_lvl >= DEBUG_CONNECTIONS) syslog(LOG_NOTICE, _("Closing connection with %s (%s)"), c->name, c->hostname); c->status.remove = 1; if(c->socket) close(c->socket); if(c->edge) { if(report) { for(node = connection_tree->head; node; node = node->next) { other = (connection_t *)node->data; if(other->status.active && other != c) send_del_edge(other, c->edge); } } edge_del(c->edge); } /* Check if this was our outgoing connection */ if(c->status.outgoing) { c->status.outgoing = 0; signal(SIGALRM, try_outgoing_connections); alarm(seconds_till_retry); syslog(LOG_NOTICE, _("Trying to re-establish outgoing connection in %d seconds"), seconds_till_retry); } /* Deactivate */ c->status.active = 0; if(c->node) c->node->connection = NULL; do_prune = 1; cp } /* Check if the other end is active. If we have sent packets, but didn't receive any, then possibly the other end is dead. We send a PING request over the meta connection. If the other end does not reply in time, we consider them dead and close the connection. */ void check_dead_connections(void) { time_t now; avl_node_t *node, *next; connection_t *c; cp now = time(NULL); for(node = connection_tree->head; node; node = next) { next = node->next; c = (connection_t *)node->data; if(c->last_ping_time + timeout < now) { if(c->status.active) { if(c->status.pinged) { if(debug_lvl >= DEBUG_PROTOCOL) syslog(LOG_INFO, _("%s (%s) didn't respond to PING"), c->name, c->hostname); c->status.timeout = 1; terminate_connection(c, 1); } else { send_ping(c); } } else { if(debug_lvl >= DEBUG_CONNECTIONS) syslog(LOG_WARNING, _("Timeout from %s (%s) during authentication"), c->name, c->hostname); terminate_connection(c, 0); } } } cp } /* accept a new tcp connect and create a new connection */ int handle_new_meta_connection() { connection_t *new; struct sockaddr client; int fd, len = sizeof(client); cp if((fd = accept(tcp_socket, &client, &len)) < 0) { syslog(LOG_ERR, _("Accepting a new connection failed: %m")); return -1; } if(!(new = create_new_connection(fd))) { shutdown(fd, 2); close(fd); syslog(LOG_NOTICE, _("Closed attempted connection")); return 0; } connection_add(new); send_id(new); cp return 0; } void randomized_alarm(int seconds) { unsigned char r; RAND_pseudo_bytes(&r, 1); alarm((seconds * (int)r) / 128 + 1); } /* This function is severely fucked up. We want to redesign it so the following rules apply: - Try all ConnectTo's in a row: - if a connect() fails, try next one immediately, - if it works, wait 5 seconds or so. - If none of them were succesful, increase delay and retry. - If all were succesful, don't try anymore. */ RETSIGTYPE try_outgoing_connections(int a) { static config_t *cfg = NULL; static int retry = 0; char *name; cp if(!cfg) cfg = lookup_config(config_tree, "ConnectTo"); if(!cfg) return; while(cfg) { get_config_string(cfg, &name); if(check_id(name)) { syslog(LOG_ERR, _("Invalid name for outgoing connection in %s line %d"), cfg->file, cfg->line); continue; } if(setup_outgoing_connection(name)) /* function returns 0 when there are no problems */ retry = 1; cfg = lookup_config_next(config_tree, cfg); /* Next time skip to next ConnectTo line */ } get_config_int(lookup_config(config_tree, "MaxTimeout"), &maxtimeout); if(retry) { seconds_till_retry += 5; if(seconds_till_retry > maxtimeout) /* Don't wait more than MAXTIMEOUT seconds. */ seconds_till_retry = maxtimeout; syslog(LOG_ERR, _("Failed to setup any outgoing connection, will retry in %d seconds"), seconds_till_retry); /* Randomize timeout to avoid global synchronisation effects */ randomized_alarm(seconds_till_retry); } else { seconds_till_retry = 5; } cp } /* check all connections to see if anything happened on their sockets */ void check_network_activity(fd_set *f) { connection_t *c; avl_node_t *node; cp if(FD_ISSET(udp_socket, f)) handle_incoming_vpn_data(); for(node = connection_tree->head; node; node = node->next) { c = (connection_t *)node->data; if(c->status.remove) return; if(FD_ISSET(c->socket, f)) if(receive_meta(c) < 0) { terminate_connection(c, c->status.active); return; } } if(FD_ISSET(tcp_socket, f)) handle_new_meta_connection(); cp } void prune_connections(void) { connection_t *c; avl_node_t *node, *next; cp for(node = connection_tree->head; node; node = next) { next = node->next; c = (connection_t *)node->data; if(c->status.remove) connection_del(c); } cp } /* this is where it all happens... */ void main_loop(void) { fd_set fset; struct timeval tv; int r; time_t last_ping_check; int t; vpn_packet_t packet; cp last_ping_check = time(NULL); for(;;) { tv.tv_sec = timeout; tv.tv_usec = 0; if(do_prune) { prune_connections(); do_prune = 0; } build_fdset(&fset); if((r = select(FD_SETSIZE, &fset, NULL, NULL, &tv)) < 0) { if(errno != EINTR) /* because of alarm */ { syslog(LOG_ERR, _("Error while waiting for input: %m")); return; } } if(sighup) { syslog(LOG_INFO, _("Rereading configuration file and restarting in 5 seconds")); sighup = 0; close_network_connections(); exit_configuration(&config_tree); if(read_server_config()) { syslog(LOG_ERR, _("Unable to reread configuration file, exiting")); exit(1); } sleep(5); if(setup_network_connections()) return; continue; } t = time(NULL); /* Let's check if everybody is still alive */ if(last_ping_check + timeout < t) { check_dead_connections(); last_ping_check = time(NULL); /* Should we regenerate our key? */ if(keyexpires < t) { if(debug_lvl >= DEBUG_STATUS) syslog(LOG_INFO, _("Regenerating symmetric key")); RAND_pseudo_bytes(myself->key, myself->keylength); send_key_changed(myself->connection, myself); keyexpires = time(NULL) + keylifetime; } } if(r > 0) { check_network_activity(&fset); /* local tap data */ if(FD_ISSET(device_fd, &fset)) { if(read_packet(&packet)) return; else route_outgoing(&packet); } } } cp }