/* net.c -- most of the network code Copyright (C) 1998,1999,2000 Ivo Timmermans , 2000 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 1.35.4.82 2000/11/25 13:33:30 guus Exp $ */ #include "config.h" #include #include #include #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 #ifdef HAVE_OPENSSL_RAND_H # include #else # include #endif #ifdef HAVE_OPENSSL_EVP_H # include #else # include #endif #ifdef HAVE_OPENSSL_ERR_H # include #else # include #endif #ifdef HAVE_TUNTAP #include LINUX_IF_TUN_H #endif #include #include #include "conf.h" #include "connection.h" #include "list.h" #include "meta.h" #include "net.h" #include "netutl.h" #include "process.h" #include "protocol.h" #include "subnet.h" #include "system.h" int tap_fd = -1; int taptype = TAP_TYPE_ETHERTAP; int total_tap_in = 0; int total_tap_out = 0; int total_socket_in = 0; int total_socket_out = 0; config_t *upstreamcfg; static int seconds_till_retry; int keylifetime = 0; int keyexpires = 0; char *unknown = NULL; subnet_t mymac; int xsend(connection_t *cl, vpn_packet_t *inpkt) { vpn_packet_t outpkt; int outlen, outpad; EVP_CIPHER_CTX ctx; struct sockaddr_in to; socklen_t tolen = sizeof(to); cp outpkt.len = inpkt->len; /* Encrypt the packet */ EVP_EncryptInit(&ctx, cl->cipher_pkttype, cl->cipher_pktkey, cl->cipher_pktkey + cl->cipher_pkttype->key_len); EVP_EncryptUpdate(&ctx, outpkt.data, &outlen, inpkt->data, inpkt->len); EVP_EncryptFinal(&ctx, outpkt.data + outlen, &outpad); outlen += outpad + 2; /* Bypass outlen = outpkt.len + 2; memcpy(&outpkt, inpkt, outlen); */ if(debug_lvl >= DEBUG_TRAFFIC) syslog(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"), outlen, cl->name, cl->hostname); total_socket_out += outlen; to.sin_family = AF_INET; to.sin_addr.s_addr = htonl(cl->address); to.sin_port = htons(cl->port); if((sendto(myself->socket, (char *) &(outpkt.len), outlen, 0, (const struct sockaddr *)&to, tolen)) < 0) { syslog(LOG_ERR, _("Error sending packet to %s (%s): %m"), cl->name, cl->hostname); return -1; } cp return 0; } int xrecv(connection_t *cl, vpn_packet_t *inpkt) { vpn_packet_t outpkt; int outlen, outpad; EVP_CIPHER_CTX ctx; cp outpkt.len = inpkt->len; /* Decrypt the packet */ EVP_DecryptInit(&ctx, myself->cipher_pkttype, myself->cipher_pktkey, myself->cipher_pktkey + myself->cipher_pkttype->key_len); EVP_DecryptUpdate(&ctx, outpkt.data, &outlen, inpkt->data, inpkt->len + 8); EVP_DecryptFinal(&ctx, outpkt.data + outlen, &outpad); outlen += outpad; /* Bypass outlen = outpkt.len+2; memcpy(&outpkt, inpkt, outlen); */ if(debug_lvl >= DEBUG_TRAFFIC) syslog(LOG_ERR, _("Writing packet of %d bytes to tap device"), outpkt.len, outlen); /* Fix mac address */ memcpy(outpkt.data, mymac.net.mac.address.x, 6); if(taptype == TAP_TYPE_TUNTAP) { if(write(tap_fd, outpkt.data, outpkt.len) < 0) syslog(LOG_ERR, _("Can't write to tun/tap device: %m")); else total_tap_out += outpkt.len; } else /* ethertap */ { if(write(tap_fd, outpkt.data - 2, outpkt.len + 2) < 0) syslog(LOG_ERR, _("Can't write to ethertap device: %m")); else total_tap_out += outpkt.len + 2; } cp return 0; } /* add the given packet of size s to the queue q, be it the send or receive queue */ void add_queue(packet_queue_t **q, void *packet, size_t s) { queue_element_t *e; cp e = xmalloc(sizeof(*e)); e->packet = xmalloc(s); memcpy(e->packet, packet, s); if(!*q) { *q = xmalloc(sizeof(**q)); (*q)->head = (*q)->tail = NULL; } e->next = NULL; /* We insert at the tail */ if((*q)->tail) /* Do we have a tail? */ { (*q)->tail->next = e; e->prev = (*q)->tail; } else /* No tail -> no head too */ { (*q)->head = e; e->prev = NULL; } (*q)->tail = e; cp } /* Remove a queue element */ void del_queue(packet_queue_t **q, queue_element_t *e) { cp free(e->packet); if(e->next) /* There is a successor, so we are not tail */ { if(e->prev) /* There is a predecessor, so we are not head */ { e->next->prev = e->prev; e->prev->next = e->next; } else /* We are head */ { e->next->prev = NULL; (*q)->head = e->next; } } else /* We are tail (or all alone!) */ { if(e->prev) /* We are not alone :) */ { e->prev->next = NULL; (*q)->tail = e->prev; } else /* Adieu */ { free(*q); *q = NULL; } } free(e); cp } /* flush a queue by calling function for each packet, and removing it when that returned a zero exit code */ void flush_queue(connection_t *cl, packet_queue_t **pq, int (*function)(connection_t*,vpn_packet_t*)) { queue_element_t *p, *next = NULL; cp for(p = (*pq)->head; p != NULL; ) { next = p->next; if(!function(cl, p->packet)) del_queue(pq, p); p = next; } if(debug_lvl >= DEBUG_TRAFFIC) syslog(LOG_DEBUG, _("Queue flushed")); cp } /* flush the send&recv queues void because nothing goes wrong here, packets remain in the queue if something goes wrong */ void flush_queues(connection_t *cl) { cp if(cl->sq) { if(debug_lvl >= DEBUG_TRAFFIC) syslog(LOG_DEBUG, _("Flushing send queue for %s (%s)"), cl->name, cl->hostname); flush_queue(cl, &(cl->sq), xsend); } if(cl->rq) { if(debug_lvl >= DEBUG_TRAFFIC) syslog(LOG_DEBUG, _("Flushing receive queue for %s (%s)"), cl->name, cl->hostname); flush_queue(cl, &(cl->rq), xrecv); } cp } /* send a packet to the given vpn ip. */ int send_packet(ip_t to, vpn_packet_t *packet) { connection_t *cl; subnet_t *subnet; cp if((subnet = lookup_subnet_ipv4(to)) == NULL) { if(debug_lvl >= DEBUG_TRAFFIC) { syslog(LOG_NOTICE, _("Trying to look up %d.%d.%d.%d in connection list failed!"), IP_ADDR_V(to)); } return -1; } cl = subnet->owner; if(cl == myself) { if(debug_lvl >= DEBUG_TRAFFIC) { syslog(LOG_NOTICE, _("Packet with destination %d.%d.%d.%d is looping back to us!"), IP_ADDR_V(to)); } return -1; } /* If we ourselves have indirectdata flag set, we should send only to our uplink! */ /* FIXME - check for indirection and reprogram it The Right Way(tm) this time. */ if(!cl->status.validkey) { /* FIXME: Don't queue until everything else is fixed. if(debug_lvl >= DEBUG_TRAFFIC) syslog(LOG_INFO, _("No valid key known yet for %s (%s), queueing packet"), cl->name, cl->hostname); add_queue(&(cl->sq), packet, packet->len + 2); */ if(!cl->status.waitingforkey) send_req_key(myself, cl); /* Keys should be sent to the host running the tincd */ return 0; } if(!cl->status.active) { /* FIXME: Don't queue until everything else is fixed. if(debug_lvl >= DEBUG_TRAFFIC) syslog(LOG_INFO, _("%s (%s) is not ready, queueing packet"), cl->name, cl->hostname); add_queue(&(cl->sq), packet, packet->len + 2); */ return 0; /* We don't want to mess up, do we? */ } /* can we send it? can we? can we? huh? */ cp return xsend(cl, packet); } /* open the local ethertap device */ int setup_tap_fd(void) { int nfd; const char *tapfname; config_t const *cfg; #ifdef HAVE_LINUX #ifdef HAVE_TUNTAP struct ifreq ifr; #endif #endif cp if((cfg = get_config_val(config, config_tapdevice))) tapfname = cfg->data.ptr; else { #ifdef HAVE_LINUX #ifdef HAVE_TUNTAP tapfname = "/dev/misc/net/tun"; #else tapfname = "/dev/tap0"; #endif #endif #ifdef HAVE_FREEBSD tapfname = "/dev/tap0"; #endif #ifdef HAVE_SOLARIS tapfname = "/dev/tun"; #endif } cp if((nfd = open(tapfname, O_RDWR | O_NONBLOCK)) < 0) { syslog(LOG_ERR, _("Could not open %s: %m"), tapfname); return -1; } cp tap_fd = nfd; taptype = TAP_TYPE_ETHERTAP; /* Set default MAC address for ethertap devices */ mymac.type = SUBNET_MAC; mymac.net.mac.address.x[0] = 0xfe; mymac.net.mac.address.x[1] = 0xfd; mymac.net.mac.address.x[2] = 0x00; mymac.net.mac.address.x[3] = 0x00; mymac.net.mac.address.x[4] = 0x00; mymac.net.mac.address.x[5] = 0x00; #ifdef HAVE_LINUX #ifdef HAVE_TUNTAP /* Ok now check if this is an old ethertap or a new tun/tap thingie */ memset(&ifr, 0, sizeof(ifr)); cp ifr.ifr_flags = IFF_TAP | IFF_NO_PI; if (netname) strncpy(ifr.ifr_name, netname, IFNAMSIZ); cp if (!ioctl(tap_fd, TUNSETIFF, (void *) &ifr)) { syslog(LOG_INFO, _("%s is a new style tun/tap device"), tapfname); taptype = TAP_TYPE_TUNTAP; } #endif #endif #ifdef HAVE_FREEBSD taptype = TAP_TYPE_TUNTAP; #endif cp return 0; } /* set up the socket that we listen on for incoming (tcp) connections */ int setup_listen_meta_socket(int port) { int nfd, flags; struct sockaddr_in a; const int one = 1; config_t const *cfg; cp if((nfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) { syslog(LOG_ERR, _("Creating metasocket failed: %m")); return -1; } if(setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one))) { close(nfd); syslog(LOG_ERR, _("System call `%s' failed: %m"), "setsockopt"); return -1; } if(setsockopt(nfd, SOL_SOCKET, SO_KEEPALIVE, &one, sizeof(one))) { close(nfd); syslog(LOG_ERR, _("System call `%s' failed: %m"), "setsockopt"); return -1; } 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"); return -1; } if((cfg = get_config_val(config, config_interface))) { if(setsockopt(nfd, SOL_SOCKET, SO_KEEPALIVE, cfg->data.ptr, strlen(cfg->data.ptr))) { close(nfd); syslog(LOG_ERR, _("Unable to bind listen socket to interface %s: %m"), cfg->data.ptr); return -1; } } memset(&a, 0, sizeof(a)); a.sin_family = AF_INET; a.sin_port = htons(port); if((cfg = get_config_val(config, config_interfaceip))) a.sin_addr.s_addr = htonl(cfg->data.ip->address); else a.sin_addr.s_addr = htonl(INADDR_ANY); if(bind(nfd, (struct sockaddr *)&a, sizeof(struct sockaddr))) { close(nfd); syslog(LOG_ERR, _("Can't bind to port %hd/tcp: %m"), port); return -1; } if(listen(nfd, 3)) { close(nfd); syslog(LOG_ERR, _("System call `%s' failed: %m"), "listen"); return -1; } cp return nfd; } /* setup the socket for incoming encrypted data (the udp part) */ int setup_vpn_in_socket(int port) { int nfd, flags; struct sockaddr_in a; const int one = 1; cp if((nfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) { close(nfd); syslog(LOG_ERR, _("Creating socket failed: %m")); return -1; } if(setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one))) { close(nfd); syslog(LOG_ERR, _("System call `%s' failed: %m"), "setsockopt"); return -1; } 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"); return -1; } memset(&a, 0, sizeof(a)); a.sin_family = AF_INET; a.sin_port = htons(port); a.sin_addr.s_addr = htonl(INADDR_ANY); if(bind(nfd, (struct sockaddr *)&a, sizeof(struct sockaddr))) { close(nfd); syslog(LOG_ERR, _("Can't bind to port %hd/udp: %m"), port); return -1; } cp return nfd; } /* setup an outgoing meta (tcp) socket */ int setup_outgoing_meta_socket(connection_t *cl) { int flags; struct sockaddr_in a; config_t const *cfg; cp if(debug_lvl >= DEBUG_CONNECTIONS) syslog(LOG_INFO, _("Trying to connect to %s"), cl->hostname); if((cfg = get_config_val(cl->config, config_port)) == NULL) cl->port = 655; else cl->port = cfg->data.val; cl->meta_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); if(cl->meta_socket == -1) { syslog(LOG_ERR, _("Creating socket for %s port %d failed: %m"), cl->hostname, cl->port); return -1; } a.sin_family = AF_INET; a.sin_port = htons(cl->port); a.sin_addr.s_addr = htonl(cl->address); if(connect(cl->meta_socket, (struct sockaddr *)&a, sizeof(a)) == -1) { close(cl->meta_socket); syslog(LOG_ERR, _("%s port %hd: %m"), cl->hostname, cl->port); return -1; } flags = fcntl(cl->meta_socket, F_GETFL); if(fcntl(cl->meta_socket, F_SETFL, flags | O_NONBLOCK) < 0) { close(cl->meta_socket); syslog(LOG_ERR, _("fcntl for %s port %d: %m"), cl->hostname, cl->port); return -1; } if(debug_lvl >= DEBUG_CONNECTIONS) syslog(LOG_INFO, _("Connected to %s port %hd"), cl->hostname, cl->port); cl->status.meta = 1; cp return 0; } /* Setup an outgoing meta connection. */ int setup_outgoing_connection(char *name) { connection_t *ncn; struct hostent *h; config_t const *cfg; cp if(check_id(name)) { syslog(LOG_ERR, _("Invalid name for outgoing connection")); return -1; } ncn = new_connection(); asprintf(&ncn->name, "%s", name); if(read_host_config(ncn)) { syslog(LOG_ERR, _("Error reading host configuration file for %s")); free_connection(ncn); return -1; } if(!(cfg = get_config_val(ncn->config, config_address))) { syslog(LOG_ERR, _("No address specified for %s")); free_connection(ncn); return -1; } if(!(h = gethostbyname(cfg->data.ptr))) { syslog(LOG_ERR, _("Error looking up `%s': %m"), cfg->data.ptr); free_connection(ncn); return -1; } ncn->address = ntohl(*((ip_t*)(h->h_addr_list[0]))); ncn->hostname = hostlookup(htonl(ncn->address)); if(setup_outgoing_meta_socket(ncn) < 0) { syslog(LOG_ERR, _("Could not set up a meta connection to %s"), ncn->hostname); free_connection(ncn); return -1; } ncn->status.outgoing = 1; ncn->buffer = xmalloc(MAXBUFSIZE); ncn->buflen = 0; ncn->last_ping_time = time(NULL); connection_add(ncn); send_id(ncn); cp return 0; } /* Configure connection_t myself and set up the local sockets (listen only) */ int setup_myself(void) { config_t const *cfg; config_t *next; subnet_t *net; cp myself = new_connection(); asprintf(&myself->hostname, "MYSELF"); /* FIXME? Do hostlookup on ourselves? */ myself->flags = 0; myself->protocol_version = PROT_CURRENT; if(!(cfg = get_config_val(config, config_name))) /* Not acceptable */ { syslog(LOG_ERR, _("Name for tinc daemon required!")); return -1; } else asprintf(&myself->name, "%s", (char*)cfg->data.val); if(check_id(myself->name)) { syslog(LOG_ERR, _("Invalid name for myself!")); return -1; } cp if(!(cfg = get_config_val(config, config_privatekey))) { syslog(LOG_ERR, _("Private key for tinc daemon required!")); return -1; } else { myself->rsa_key = RSA_new(); BN_hex2bn(&myself->rsa_key->d, cfg->data.ptr); BN_hex2bn(&myself->rsa_key->e, "FFFF"); } if(read_host_config(myself)) { syslog(LOG_ERR, _("Cannot open host configuration file for myself!")); return -1; } cp if(!(cfg = get_config_val(myself->config, config_publickey))) { syslog(LOG_ERR, _("Public key for tinc daemon required!")); return -1; } else { BN_hex2bn(&myself->rsa_key->n, cfg->data.ptr); } /* if(RSA_check_key(myself->rsa_key) != 1) { syslog(LOG_ERR, _("Invalid public/private keypair!")); return -1; } */ if(!(cfg = get_config_val(myself->config, config_port))) myself->port = 655; else myself->port = cfg->data.val; if((cfg = get_config_val(myself->config, config_indirectdata))) if(cfg->data.val == stupid_true) myself->flags |= EXPORTINDIRECTDATA; if((cfg = get_config_val(myself->config, config_tcponly))) if(cfg->data.val == stupid_true) myself->flags |= TCPONLY; /* Read in all the subnets specified in the host configuration file */ for(next = myself->config; (cfg = get_config_val(next, config_subnet)); next = cfg->next) { net = new_subnet(); net->type = SUBNET_IPV4; net->net.ipv4.address = cfg->data.ip->address; net->net.ipv4.mask = cfg->data.ip->mask; /* Teach newbies what subnets are... */ if((net->net.ipv4.address & net->net.ipv4.mask) != net->net.ipv4.address) { syslog(LOG_ERR, _("Network address and subnet mask do not match!")); return -1; } subnet_add(myself, net); } if((myself->meta_socket = setup_listen_meta_socket(myself->port)) < 0) { syslog(LOG_ERR, _("Unable to set up a listening TCP socket!")); return -1; } if((myself->socket = setup_vpn_in_socket(myself->port)) < 0) { syslog(LOG_ERR, _("Unable to set up a listening UDP socket!")); return -1; } /* Generate packet encryption key */ myself->cipher_pkttype = EVP_bf_cfb(); myself->cipher_pktkeylength = myself->cipher_pkttype->key_len + myself->cipher_pkttype->iv_len; myself->cipher_pktkey = (char *)xmalloc(myself->cipher_pktkeylength); RAND_bytes(myself->cipher_pktkey, myself->cipher_pktkeylength); if(!(cfg = get_config_val(config, config_keyexpire))) keylifetime = 3600; else keylifetime = cfg->data.val; keyexpires = time(NULL) + keylifetime; /* Activate ourselves */ myself->status.active = 1; syslog(LOG_NOTICE, _("Ready: listening on port %hd"), myself->port); cp return 0; } RETSIGTYPE sigalrm_handler(int a) { config_t const *cfg; cp cfg = get_config_val(upstreamcfg, config_connectto); if(!cfg && upstreamcfg == config) /* No upstream IP given, we're listen only. */ return; while(cfg) { upstreamcfg = cfg->next; if(!setup_outgoing_connection(cfg->data.ptr)) /* function returns 0 when there are no problems */ { signal(SIGALRM, SIG_IGN); return; } cfg = get_config_val(upstreamcfg, config_connectto); /* Or else we try the next ConnectTo line */ } signal(SIGALRM, sigalrm_handler); upstreamcfg = config; seconds_till_retry += 5; if(seconds_till_retry > MAXTIMEOUT) /* Don't wait more than MAXTIMEOUT seconds. */ seconds_till_retry = MAXTIMEOUT; syslog(LOG_ERR, _("Still failed to connect to other, will retry in %d seconds"), seconds_till_retry); alarm(seconds_till_retry); cp } /* setup all initial network connections */ int setup_network_connections(void) { config_t const *cfg; cp init_connections(); init_subnets(); if((cfg = get_config_val(config, config_pingtimeout)) == NULL) timeout = 60; else { timeout = cfg->data.val; if(timeout < 1) { timeout = 86400; } } if(setup_tap_fd() < 0) return -1; /* Run tinc-up script to further initialize the tap interface */ execute_script("tinc-up"); if(setup_myself() < 0) return -1; if(!(cfg = get_config_val(config, config_connectto))) /* No upstream IP given, we're listen only. */ return 0; while(cfg) { upstreamcfg = cfg->next; if(!setup_outgoing_connection(cfg->data.ptr)) /* function returns 0 when there are no problems */ return 0; cfg = get_config_val(upstreamcfg, config_connectto); /* Or else we try the next ConnectTo line */ } signal(SIGALRM, sigalrm_handler); upstreamcfg = config; seconds_till_retry = MAXTIMEOUT; syslog(LOG_NOTICE, _("Trying to re-establish outgoing connection in %d seconds"), seconds_till_retry); alarm(seconds_till_retry); cp return 0; } /* close all open network connections */ void close_network_connections(void) { rbl_t *rbl; connection_t *p; cp RBL_FOREACH(connection_tree, rbl) { p = (connection_t *)rbl->data; p->status.active = 0; terminate_connection(p); } if(myself) if(myself->status.active) { close(myself->meta_socket); free_connection(myself); myself = NULL; } close(tap_fd); /* Execute tinc-down script right after shutting down the interface */ execute_script("tinc-down"); destroy_connection_tree(); cp return; } /* create a data (udp) socket OBSOLETED: use only one listening socket for compatibility with non-Linux operating systems */ int setup_vpn_connection(connection_t *cl) { int nfd, flags; struct sockaddr_in a; const int one = 1; cp if(debug_lvl >= DEBUG_TRAFFIC) syslog(LOG_DEBUG, _("Opening UDP socket to %s"), cl->hostname); nfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); if(nfd == -1) { syslog(LOG_ERR, _("Creating UDP socket failed: %m")); return -1; } if(setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one))) { close(nfd); syslog(LOG_ERR, _("System call `%s' failed: %m"), "setsockopt"); return -1; } 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"); return -1; } memset(&a, 0, sizeof(a)); a.sin_family = AF_INET; a.sin_port = htons(myself->port); a.sin_addr.s_addr = htonl(INADDR_ANY); if(bind(nfd, (struct sockaddr *)&a, sizeof(struct sockaddr))) { close(nfd); syslog(LOG_ERR, _("Can't bind to port %hd/udp: %m"), myself->port); return -1; } a.sin_family = AF_INET; a.sin_port = htons(cl->port); a.sin_addr.s_addr = htonl(cl->address); if(connect(nfd, (struct sockaddr *)&a, sizeof(a)) == -1) { close(nfd); syslog(LOG_ERR, _("Connecting to %s port %d failed: %m"), cl->hostname, cl->port); return -1; } flags = fcntl(nfd, F_GETFL); if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) { close(nfd); syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%m %s (%s)"), __FILE__, __LINE__, nfd, cl->name, cl->hostname); return -1; } cl->socket = nfd; cl->status.dataopen = 1; cp return 0; } /* handle an incoming tcp connect call and open a connection to it. */ connection_t *create_new_connection(int sfd) { connection_t *p; struct sockaddr_in ci; int len = sizeof(ci); cp p = new_connection(); if(getpeername(sfd, (struct sockaddr *) &ci, (socklen_t *) &len) < 0) { syslog(LOG_ERR, _("System call `%s' failed: %m"), "getpeername"); return NULL; } p->name = unknown; p->address = ntohl(ci.sin_addr.s_addr); p->hostname = hostlookup(ci.sin_addr.s_addr); p->meta_socket = sfd; p->status.meta = 1; p->buffer = xmalloc(MAXBUFSIZE); p->buflen = 0; p->last_ping_time = time(NULL); if(debug_lvl >= DEBUG_CONNECTIONS) syslog(LOG_NOTICE, _("Connection from %s port %d"), p->hostname, htons(ci.sin_port)); p->allow_request = ID; cp return p; } /* put all file descriptors in an fd_set array */ void build_fdset(fd_set *fs) { rbl_t *rbl; connection_t *p; cp FD_ZERO(fs); FD_SET(myself->socket, fs); RBL_FOREACH(connection_tree, rbl) { p = (connection_t *)rbl->data; if(p->status.meta) FD_SET(p->meta_socket, fs); } FD_SET(myself->meta_socket, fs); FD_SET(tap_fd, fs); cp } /* receive incoming data from the listening udp socket and write it to the ethertap device after being decrypted */ int handle_incoming_vpn_data(void) { vpn_packet_t pkt; int x, l = sizeof(x); int lenin; struct sockaddr_in from; socklen_t fromlen = sizeof(from); connection_t *cl; cp if(getsockopt(myself->socket, SOL_SOCKET, SO_ERROR, &x, &l) < 0) { syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%m"), __FILE__, __LINE__, myself->socket); return -1; } if(x) { syslog(LOG_ERR, _("Incoming data socket error: %s"), strerror(x)); return -1; } if((lenin = recvfrom(myself->socket, (char *) &(pkt.len), MTU, 0, (struct sockaddr *)&from, &fromlen)) <= 0) { syslog(LOG_ERR, _("Receiving packet failed: %m")); return -1; } cl = lookup_connection(ntohl(from.sin_addr.s_addr), ntohs(from.sin_port)); if(!cl) { syslog(LOG_WARNING, _("Received UDP packets on port %d from unknown source %lx:%d"), ntohl(from.sin_addr.s_addr), ntohs(from.sin_port)); return 0; } if(debug_lvl >= DEBUG_TRAFFIC) { syslog(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"), lenin, cl->name, cl->hostname); } cp return xrecv(cl, &pkt); } /* terminate a connection and notify the other end before closing the sockets */ void terminate_connection(connection_t *cl) { connection_t *p; subnet_t *subnet; rbl_t *rbl; cp if(cl->status.remove) return; cl->status.remove = 1; if(debug_lvl >= DEBUG_CONNECTIONS) syslog(LOG_NOTICE, _("Closing connection with %s (%s)"), cl->name, cl->hostname); if(cl->socket) close(cl->socket); if(cl->status.meta) close(cl->meta_socket); /* Find all connections that were lost because they were behind cl (the connection that was dropped). */ if(cl->status.meta) RBL_FOREACH(connection_tree, rbl) { p = (connection_t *)rbl->data; if(p->nexthop == cl && p != cl) terminate_connection(p); } /* Inform others of termination if it was still active */ if(cl->status.active) RBL_FOREACH(connection_tree, rbl) { p = (connection_t *)rbl->data; if(p->status.meta && p->status.active && p!=cl) send_del_host(p, cl); /* Sounds like recursion, but p does not have a meta connection :) */ } /* Remove the associated subnets */ RBL_FOREACH(cl->subnet_tree, rbl) { subnet = (subnet_t *)rbl->data; subnet_del(subnet); } /* Check if this was our outgoing connection */ if(cl->status.outgoing && cl->status.active) { signal(SIGALRM, sigalrm_handler); seconds_till_retry = 5; alarm(seconds_till_retry); syslog(LOG_NOTICE, _("Trying to re-establish outgoing connection in 5 seconds")); } /* Inactivate */ cl->status.active = 0; 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; rbl_t *rbl; connection_t *cl; cp now = time(NULL); RBL_FOREACH(connection_tree, rbl) { cl = (connection_t *)rbl->data; if(cl->status.active && cl->status.meta) { if(cl->last_ping_time + timeout < now) { if(cl->status.pinged) { if(debug_lvl >= DEBUG_PROTOCOL) syslog(LOG_INFO, _("%s (%s) didn't respond to PING"), cl->name, cl->hostname); cl->status.timeout = 1; terminate_connection(cl); } else { send_ping(cl); } } } } cp } /* accept a new tcp connect and create a new connection */ int handle_new_meta_connection() { connection_t *ncn; struct sockaddr client; int nfd, len = sizeof(client); cp if((nfd = accept(myself->meta_socket, &client, &len)) < 0) { syslog(LOG_ERR, _("Accepting a new connection failed: %m")); return -1; } if(!(ncn = create_new_connection(nfd))) { shutdown(nfd, 2); close(nfd); syslog(LOG_NOTICE, _("Closed attempted connection")); return 0; } connection_add(ncn); cp return 0; } /* check all connections to see if anything happened on their sockets */ void check_network_activity(fd_set *f) { connection_t *p; rbl_t *rbl; cp if(FD_ISSET(myself->socket, f)) handle_incoming_vpn_data(); RBL_FOREACH(connection_tree, rbl) { p = (connection_t *)rbl->data; if(p->status.remove) return; if(p->status.meta) if(FD_ISSET(p->meta_socket, f)) if(receive_meta(p) < 0) { terminate_connection(p); return; } } if(FD_ISSET(myself->meta_socket, f)) handle_new_meta_connection(); cp } /* read, encrypt and send data that is available through the ethertap device */ void handle_tap_input(void) { vpn_packet_t vp; int lenin; cp if(taptype == TAP_TYPE_TUNTAP) { if((lenin = read(tap_fd, vp.data, MTU)) <= 0) { syslog(LOG_ERR, _("Error while reading from tun/tap device: %m")); return; } vp.len = lenin; } else /* ethertap */ { if((lenin = read(tap_fd, vp.data - 2, MTU)) <= 0) { syslog(LOG_ERR, _("Error while reading from ethertap device: %m")); return; } vp.len = lenin - 2; } total_tap_in += lenin; if(lenin < 32) { if(debug_lvl >= DEBUG_TRAFFIC) syslog(LOG_WARNING, _("Received short packet from tap device")); return; } if(debug_lvl >= DEBUG_TRAFFIC) { syslog(LOG_DEBUG, _("Read packet of length %d from tap device"), vp.len); } send_packet(ntohl(*((unsigned long*)(&vp.data[30]))), &vp); 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; cp last_ping_check = time(NULL); for(;;) { tv.tv_sec = timeout; tv.tv_usec = 0; prune_connection_tree(); 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(); clear_config(&config); if(read_server_config()) { syslog(LOG_ERR, _("Unable to reread configuration file, exiting")); exit(0); } 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_bytes(myself->cipher_pktkey, myself->cipher_pktkeylength); send_key_changed(myself, NULL); keyexpires = time(NULL) + keylifetime; } } if(r > 0) { check_network_activity(&fset); /* local tap data */ if(FD_ISSET(tap_fd, &fset)) handle_tap_input(); } } cp }