2 net.c -- most of the network code
3 Copyright (C) 1998,1999,2000 Ivo Timmermans <itimmermans@bigfoot.com>,
4 2000 Guus Sliepen <guus@sliepen.warande.net>
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 $Id: net.c,v 1.35.4.16 2000/06/30 11:45:14 guus Exp $
25 #include <arpa/inet.h>
29 #include <netinet/in.h>
33 #include <sys/signal.h>
34 #include <sys/socket.h>
36 #include <sys/types.h>
55 int total_tap_out = 0;
56 int total_socket_in = 0;
57 int total_socket_out = 0;
59 int upstreamindex = 0;
60 static int seconds_till_retry;
62 /* The global list of existing connections */
63 conn_list_t *conn_list = NULL;
64 conn_list_t *myself = NULL;
67 strip off the MAC adresses of an ethernet frame
69 void strip_mac_addresses(vpn_packet_t *p)
71 unsigned char tmp[MAXSIZE];
73 memcpy(tmp, p->data, p->len);
75 memcpy(p->data, &tmp[12], p->len);
80 reassemble MAC addresses
82 void add_mac_addresses(vpn_packet_t *p)
84 unsigned char tmp[MAXSIZE];
86 memcpy(&tmp[12], p->data, p->len);
88 tmp[0] = tmp[6] = 0xfe;
89 tmp[1] = tmp[7] = 0xfd;
90 *((ip_t*)(&tmp[2])) = (ip_t)(htonl(myself->vpn_ip));
91 *((ip_t*)(&tmp[8])) = *((ip_t*)(&tmp[26]));
92 memcpy(p->data, &tmp[0], p->len);
96 int xsend(conn_list_t *cl, void *packet)
101 do_encrypt((vpn_packet_t*)packet, &rp, cl->key);
102 rp.from = htonl(myself->vpn_ip);
103 rp.data.len = htons(rp.data.len);
104 rp.len = htons(rp.len);
107 syslog(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"),
108 ntohs(rp.len), cl->vpn_hostname, cl->real_hostname);
110 if((r = send(cl->socket, (char*)&rp, ntohs(rp.len), 0)) < 0)
112 syslog(LOG_ERR, _("Error sending packet to %s (%s): %m"),
113 cl->vpn_hostname, cl->real_hostname);
117 total_socket_out += r;
124 int xrecv(conn_list_t *cl, void *packet)
129 do_decrypt((real_packet_t*)packet, &vp, cl->key);
130 add_mac_addresses(&vp);
133 syslog(LOG_ERR, _("Receiving packet of %d bytes from %s (%s)"),
134 ((real_packet_t*)packet)->len, cl->vpn_hostname, cl->real_hostname);
136 if((lenin = write(tap_fd, &vp, vp.len + sizeof(vp.len))) < 0)
137 syslog(LOG_ERR, _("Can't write to tap device: %m"));
139 total_tap_out += lenin;
142 cl->last_ping_time = time(NULL);
148 add the given packet of size s to the
149 queue q, be it the send or receive queue
151 void add_queue(packet_queue_t **q, void *packet, size_t s)
155 e = xmalloc(sizeof(*e));
156 e->packet = xmalloc(s);
157 memcpy(e->packet, packet, s);
161 *q = xmalloc(sizeof(**q));
162 (*q)->head = (*q)->tail = NULL;
165 e->next = NULL; /* We insert at the tail */
167 if((*q)->tail) /* Do we have a tail? */
169 (*q)->tail->next = e;
170 e->prev = (*q)->tail;
172 else /* No tail -> no head too */
182 /* Remove a queue element */
183 void del_queue(packet_queue_t **q, queue_element_t *e)
188 if(e->next) /* There is a successor, so we are not tail */
190 if(e->prev) /* There is a predecessor, so we are not head */
192 e->next->prev = e->prev;
193 e->prev->next = e->next;
195 else /* We are head */
197 e->next->prev = NULL;
198 (*q)->head = e->next;
201 else /* We are tail (or all alone!) */
203 if(e->prev) /* We are not alone :) */
205 e->prev->next = NULL;
206 (*q)->tail = e->prev;
220 flush a queue by calling function for
221 each packet, and removing it when that
222 returned a zero exit code
224 void flush_queue(conn_list_t *cl, packet_queue_t **pq,
225 int (*function)(conn_list_t*,void*))
227 queue_element_t *p, *next = NULL;
229 for(p = (*pq)->head; p != NULL; )
233 if(!function(cl, p->packet))
240 syslog(LOG_DEBUG, _("Queue flushed"));
245 flush the send&recv queues
246 void because nothing goes wrong here, packets
247 remain in the queue if something goes wrong
249 void flush_queues(conn_list_t *cl)
255 syslog(LOG_DEBUG, _("Flushing send queue for %s (%s)"),
256 cl->vpn_hostname, cl->real_hostname);
257 flush_queue(cl, &(cl->sq), xsend);
263 syslog(LOG_DEBUG, _("Flushing receive queue for %s (%s)"),
264 cl->vpn_hostname, cl->real_hostname);
265 flush_queue(cl, &(cl->rq), xrecv);
271 send a packet to the given vpn ip.
273 int send_packet(ip_t to, vpn_packet_t *packet)
277 if((cl = lookup_conn(to)) == NULL)
281 syslog(LOG_NOTICE, _("Trying to look up %d.%d.%d.%d in connection list failed!"),
285 /* Is this really necessary? If we can't find "to", then neither should any uplink. (GS) */
289 for(cl = conn_list; cl != NULL && !cl->status.outgoing; cl = cl->next);
291 { /* No open outgoing connection has been found. */
293 syslog(LOG_NOTICE, _("There is no remote host I can send this packet to!"));
298 /* If we ourselves have indirectdata flag set, we should send only to our uplink! */
300 if(myself->flags & EXPORTINDIRECTDATA)
302 for(cl = conn_list; cl != NULL && !cl->status.outgoing; cl = cl->next);
304 { /* No open outgoing connection has been found. */
306 syslog(LOG_NOTICE, _("There is no remote host I can send this packet to!"));
312 /* If indirectdata flag is set for the destination we just looked up,
313 * then real_ip is actually the vpn_ip of the gateway tincd
317 if(cl->flags & INDIRECTDATA)
320 syslog(LOG_NOTICE, _("Indirect packet to %s via %s"),
321 cl->vpn_hostname, cl->real_hostname);
322 if((cl = lookup_conn(cl->real_ip)) == NULL)
325 syslog(LOG_NOTICE, _("Indirect look up %d.%d.%d.%d in connection list failed!"),
328 /* Gateway tincd dead? Should we kill it? (GS) */
332 if(cl->flags & INDIRECTDATA) /* This should not happen */
335 syslog(LOG_NOTICE, _("Double indirection for %d.%d.%d.%d"),
341 if(my_key_expiry <= time(NULL))
344 if(!cl->status.dataopen)
345 if(setup_vpn_connection(cl) < 0)
347 syslog(LOG_ERR, _("Could not open UDP connection to %s (%s)"), cl->vpn_hostname, cl->real_hostname);
351 if(!cl->status.validkey)
354 syslog(LOG_INFO, _("%s (%s) has no valid key, queueing packet"), cl->vpn_hostname, cl->real_hostname);
355 add_queue(&(cl->sq), packet, packet->len + 2);
356 if(!cl->status.waitingforkey)
357 send_key_request(cl->vpn_ip); /* Keys should be sent to the host running the tincd */
361 if(!cl->status.active)
364 syslog(LOG_INFO, _("%s (%s) is not ready, queueing packet"), cl->vpn_hostname, cl->real_hostname);
365 add_queue(&(cl->sq), packet, packet->len + 2);
366 return 0; /* We don't want to mess up, do we? */
369 /* can we send it? can we? can we? huh? */
371 return xsend(cl, packet);
375 open the local ethertap device
377 int setup_tap_fd(void)
380 const char *tapfname;
383 if((cfg = get_config_val(tapdevice)) == NULL)
384 tapfname = "/dev/tap0";
386 tapfname = cfg->data.ptr;
388 if((nfd = open(tapfname, O_RDWR | O_NONBLOCK)) < 0)
390 syslog(LOG_ERR, _("Could not open %s: %m"), tapfname);
400 set up the socket that we listen on for incoming
403 int setup_listen_meta_socket(int port)
406 struct sockaddr_in a;
409 if((nfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
411 syslog(LOG_ERR, _("Creating metasocket failed: %m"));
415 if(setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)))
417 syslog(LOG_ERR, _("setsockopt: %m"));
421 flags = fcntl(nfd, F_GETFL);
422 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0)
424 syslog(LOG_ERR, _("fcntl: %m"));
428 memset(&a, 0, sizeof(a));
429 a.sin_family = AF_INET;
430 a.sin_port = htons(port);
431 a.sin_addr.s_addr = htonl(INADDR_ANY);
433 if(bind(nfd, (struct sockaddr *)&a, sizeof(struct sockaddr)))
435 syslog(LOG_ERR, _("Can't bind to port %hd/tcp: %m"), port);
441 syslog(LOG_ERR, _("listen: %m"));
449 setup the socket for incoming encrypted
452 int setup_vpn_in_socket(int port)
455 struct sockaddr_in a;
458 if((nfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
460 syslog(LOG_ERR, _("Creating socket failed: %m"));
464 if(setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)))
466 syslog(LOG_ERR, _("setsockopt: %m"));
470 flags = fcntl(nfd, F_GETFL);
471 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0)
473 syslog(LOG_ERR, _("fcntl: %m"));
477 memset(&a, 0, sizeof(a));
478 a.sin_family = AF_INET;
479 a.sin_port = htons(port);
480 a.sin_addr.s_addr = htonl(INADDR_ANY);
482 if(bind(nfd, (struct sockaddr *)&a, sizeof(struct sockaddr)))
484 syslog(LOG_ERR, _("Can't bind to port %hd/udp: %m"), port);
492 setup an outgoing meta (tcp) socket
494 int setup_outgoing_meta_socket(conn_list_t *cl)
497 struct sockaddr_in a;
501 syslog(LOG_INFO, _("Trying to connect to %s"), cl->real_hostname);
503 if((cfg = get_config_val(upstreamport)) == NULL)
506 cl->port = cfg->data.val;
508 cl->meta_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
509 if(cl->meta_socket == -1)
511 syslog(LOG_ERR, _("Creating socket failed: %m"));
515 a.sin_family = AF_INET;
516 a.sin_port = htons(cl->port);
517 a.sin_addr.s_addr = htonl(cl->real_ip);
519 if(connect(cl->meta_socket, (struct sockaddr *)&a, sizeof(a)) == -1)
521 syslog(LOG_ERR, _("%s port %hd: %m"), cl->real_hostname, cl->port);
525 flags = fcntl(cl->meta_socket, F_GETFL);
526 if(fcntl(cl->meta_socket, F_SETFL, flags | O_NONBLOCK) < 0)
528 syslog(LOG_ERR, _("fcntl: %m"));
532 syslog(LOG_INFO, _("Connected to %s port %hd"),
533 cl->real_hostname, cl->port);
539 setup an outgoing connection. It's not
540 necessary to also open an udp socket as
541 well, because the other host will initiate
542 an authentication sequence during which
543 we will do just that.
545 int setup_outgoing_connection(ip_t ip)
549 ncn = new_conn_list();
551 ncn->real_hostname = hostlookup(htonl(ip));
553 if(setup_outgoing_meta_socket(ncn) < 0)
555 syslog(LOG_ERR, _("Could not set up a meta connection to %s"),
557 free_conn_element(ncn);
561 ncn->status.meta = 1;
562 ncn->status.outgoing = 1;
563 ncn->next = conn_list;
570 set up the local sockets (listen only)
572 int setup_myself(void)
576 myself = new_conn_list();
578 if(!(cfg = get_config_val(myvpnip)))
580 syslog(LOG_ERR, _("No value for my VPN IP given"));
584 myself->vpn_ip = cfg->data.ip->ip;
585 myself->vpn_hostname = hostlookup(htonl(myself->vpn_ip));
586 myself->real_hostname = hostlookup(htonl(myself->vpn_ip));
587 myself->vpn_mask = cfg->data.ip->mask;
590 if(!(cfg = get_config_val(listenport)))
593 myself->port = cfg->data.val;
595 if(cfg = get_config_val(indirectdata))
596 if(cfg->data.val == stupid_true)
597 myself->flags |= EXPORTINDIRECTDATA;
599 if((myself->meta_socket = setup_listen_meta_socket(myself->port)) < 0)
601 syslog(LOG_ERR, _("Unable to set up a listening socket"));
605 if((myself->socket = setup_vpn_in_socket(myself->port)) < 0)
607 syslog(LOG_ERR, _("Unable to set up an incoming vpn data socket"));
608 close(myself->meta_socket);
612 myself->status.active = 1;
614 syslog(LOG_NOTICE, _("Ready: listening on port %hd"), myself->port);
620 sigalrm_handler(int a)
624 cfg = get_next_config_val(upstreamip, upstreamindex++);
628 if(!setup_outgoing_connection(cfg->data.ip->ip)) /* function returns 0 when there are no problems */
630 signal(SIGALRM, SIG_IGN);
633 cfg = get_next_config_val(upstreamip, upstreamindex++); /* Or else we try the next ConnectTo line */
636 signal(SIGALRM, sigalrm_handler);
638 seconds_till_retry += 5;
639 if(seconds_till_retry > MAXTIMEOUT) /* Don't wait more than MAXTIMEOUT seconds. */
640 seconds_till_retry = MAXTIMEOUT;
641 syslog(LOG_ERR, _("Still failed to connect to other, will retry in %d seconds"),
643 alarm(seconds_till_retry);
648 setup all initial network connections
650 int setup_network_connections(void)
654 if((cfg = get_config_val(pingtimeout)) == NULL)
657 timeout = cfg->data.val;
659 if(setup_tap_fd() < 0)
662 if(setup_myself() < 0)
665 if((cfg = get_next_config_val(upstreamip, upstreamindex++)) == NULL)
666 /* No upstream IP given, we're listen only. */
671 if(!setup_outgoing_connection(cfg->data.ip->ip)) /* function returns 0 when there are no problems */
673 cfg = get_next_config_val(upstreamip, upstreamindex++); /* Or else we try the next ConnectTo line */
676 signal(SIGALRM, sigalrm_handler);
678 seconds_till_retry = MAXTIMEOUT;
679 syslog(LOG_NOTICE, _("Trying to re-establish outgoing connection in %d seconds"), seconds_till_retry);
680 alarm(seconds_till_retry);
686 close all open network connections
688 void close_network_connections(void)
692 for(p = conn_list; p != NULL; p = p->next)
694 if(p->status.dataopen)
696 shutdown(p->socket, 0); /* No more receptions */
702 shutdown(p->meta_socket, 0); /* No more receptions */
703 close(p->meta_socket);
708 if(myself->status.active)
710 close(myself->meta_socket);
711 close(myself->socket);
717 syslog(LOG_NOTICE, _("Terminating"));
723 create a data (udp) socket
725 int setup_vpn_connection(conn_list_t *cl)
728 struct sockaddr_in a;
731 syslog(LOG_DEBUG, _("Opening UDP socket to %s"), cl->real_hostname);
733 nfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
736 syslog(LOG_ERR, _("Creating UDP socket failed: %m"));
740 a.sin_family = AF_INET;
741 a.sin_port = htons(cl->port);
742 a.sin_addr.s_addr = htonl(cl->real_ip);
744 if(connect(nfd, (struct sockaddr *)&a, sizeof(a)) == -1)
746 syslog(LOG_ERR, _("Connecting to %s port %d failed: %m"),
747 cl->real_hostname, cl->port);
751 flags = fcntl(nfd, F_GETFL);
752 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0)
754 syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%m"), __FILE__, __LINE__, nfd);
759 cl->status.dataopen = 1;
765 handle an incoming tcp connect call and open
768 conn_list_t *create_new_connection(int sfd)
771 struct sockaddr_in ci;
772 int len = sizeof(ci);
776 if(getpeername(sfd, &ci, &len) < 0)
778 syslog(LOG_ERR, _("Error: getpeername: %m"));
782 p->real_ip = ntohl(ci.sin_addr.s_addr);
783 p->real_hostname = hostlookup(ci.sin_addr.s_addr);
784 p->meta_socket = sfd;
787 p->last_ping_time = time(NULL);
791 syslog(LOG_NOTICE, _("Connection from %s port %d"),
792 p->real_hostname, htons(ci.sin_port));
794 if(send_basic_info(p) < 0)
796 free_conn_element(p);
804 put all file descriptors in an fd_set array
806 void build_fdset(fd_set *fs)
812 for(p = conn_list; p != NULL; p = p->next)
815 FD_SET(p->meta_socket, fs);
816 if(p->status.dataopen)
817 FD_SET(p->socket, fs);
820 FD_SET(myself->meta_socket, fs);
821 FD_SET(myself->socket, fs);
827 receive incoming data from the listening
828 udp socket and write it to the ethertap
829 device after being decrypted
831 int handle_incoming_vpn_data(conn_list_t *cl)
835 int x, l = sizeof(x);
838 if(getsockopt(cl->socket, SOL_SOCKET, SO_ERROR, &x, &l) < 0)
840 syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%m"), __FILE__, __LINE__, cl->socket);
845 syslog(LOG_ERR, _("Incoming data socket error: %s"), sys_errlist[x]);
850 lenin = recvfrom(cl->socket, &rp, MTU, 0, NULL, NULL);
853 syslog(LOG_ERR, _("Receiving packet from %s failed: %m"), cl->real_hostname);
856 total_socket_in += lenin;
858 rp.data.len = ntohs(rp.data.len);
859 rp.len = ntohs(rp.len);
860 rp.from = ntohl(rp.from);
864 f = lookup_conn(rp.from);
867 syslog(LOG_ERR, _("Got packet from %s (%s) with unknown origin %d.%d.%d.%d?"),
868 cl->vpn_hostname, cl->real_hostname, IP_ADDR_V(rp.from));
872 if(f->status.validkey)
876 add_queue(&(f->rq), &rp, rp.len);
877 if(!cl->status.waitingforkey)
878 send_key_request(rp.from);
881 if(my_key_expiry <= time(NULL))
889 terminate a connection and notify the other
890 end before closing the sockets
892 void terminate_connection(conn_list_t *cl)
897 if(cl->status.remove)
901 syslog(LOG_NOTICE, _("Closing connection with %s (%s)"),
902 cl->vpn_hostname, cl->real_hostname);
904 if(cl->status.timeout)
906 /* else if(!cl->status.termreq)
913 close(cl->meta_socket);
915 cl->status.remove = 1;
917 /* If this cl isn't active, don't send any DEL_HOSTs. */
918 if(cl->status.active)
919 notify_others(cl,NULL,send_del_host);
922 /* Find all connections that were lost because they were behind cl
923 (the connection that was dropped). */
925 for(p = conn_list; p != NULL; p = p->next)
927 if((p->nexthop == cl) && (p != cl))
929 if(cl->status.active && p->status.active)
930 notify_others(p,cl,send_del_host);
933 p->status.active = 0;
934 p->status.remove = 1;
938 cl->status.active = 0;
940 if(cl->status.outgoing)
942 signal(SIGALRM, sigalrm_handler);
943 seconds_till_retry = 5;
944 alarm(seconds_till_retry);
945 syslog(LOG_NOTICE, _("Trying to re-establish outgoing connection in 5 seconds"));
951 Check if the other end is active.
952 If we have sent packets, but didn't receive any,
953 then possibly the other end is dead. We send a
954 PING request over the meta connection. If the other
955 end does not reply in time, we consider them dead
956 and close the connection.
958 int check_dead_connections(void)
964 for(p = conn_list; p != NULL; p = p->next)
968 if(p->status.active && p->status.meta)
970 if(p->last_ping_time + timeout < now)
972 if(p->status.pinged && !p->status.got_pong)
975 syslog(LOG_INFO, _("%s (%s) didn't respond to PING"),
976 p->vpn_hostname, p->real_hostname);
977 p->status.timeout = 1;
978 terminate_connection(p);
980 else if(p->want_ping)
983 p->last_ping_time = now;
984 p->status.pinged = 1;
985 p->status.got_pong = 0;
995 accept a new tcp connect and create a
998 int handle_new_meta_connection(conn_list_t *cl)
1001 struct sockaddr client;
1002 int nfd, len = sizeof(client);
1004 if((nfd = accept(cl->meta_socket, &client, &len)) < 0)
1006 syslog(LOG_ERR, _("Accepting a new connection failed: %m"));
1010 if(!(ncn = create_new_connection(nfd)))
1014 syslog(LOG_NOTICE, _("Closed attempted connection"));
1018 ncn->status.meta = 1;
1019 ncn->next = conn_list;
1026 dispatch any incoming meta requests
1028 int handle_incoming_meta_data(conn_list_t *cl)
1030 int x, l = sizeof(x);
1031 int request, oldlen, i;
1034 if(getsockopt(cl->meta_socket, SOL_SOCKET, SO_ERROR, &x, &l) < 0)
1036 syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%m"), __FILE__, __LINE__, cl->meta_socket);
1041 syslog(LOG_ERR, _("Metadata socket error: %s"), sys_errlist[x]);
1045 if(cl->buflen >= MAXBUFSIZE)
1047 syslog(LOG_ERR, _("Metadata read buffer overflow!"));
1051 lenin = read(cl->meta_socket, cl->buffer, MAXBUFSIZE-cl->buflen);
1057 syslog(LOG_ERR, _("Metadata socket read error: %m"));
1061 oldlen = cl->buflen;
1062 cl->buflen += lenin;
1068 for(i = oldlen; i < cl->buflen; i++)
1070 if(cl->buffer[i] == '\n')
1072 cl->buffer[i] = 0; /* replace end-of-line by end-of-string so we can use sscanf */
1081 syslog(LOG_DEBUG, _("Got request from %s (%s): %s"),
1082 cl->vpn_hostname, cl->real_hostname, cl->buffer);
1083 if(sscanf(cl->buffer, "%d", &request) == 1)
1085 if((request < 0) || (request > 255) || (request_handlers[request] == NULL))
1087 syslog(LOG_ERR, _("Unknown request from %s (%s)"),
1088 cl->vpn_hostname, cl->real_hostname);
1092 if(request_handlers[request](cl)) /* Something went wrong. Probably scriptkiddies. Terminate. */
1094 syslog(LOG_ERR, _("Error while processing request from %s (%s)"),
1095 cl->vpn_hostname, cl->real_hostname);
1101 syslog(LOG_ERR, _("Bogus data received from %s (%s)"),
1102 cl->vpn_hostname, cl->real_hostname);
1106 cl->buflen -= cl->reqlen;
1107 memmove(cl->buffer, cl->buffer + cl->reqlen, cl->buflen);
1116 cl->last_ping_time = time(NULL);
1123 check all connections to see if anything
1124 happened on their sockets
1126 void check_network_activity(fd_set *f)
1129 int x, l = sizeof(x);
1131 for(p = conn_list; p != NULL; p = p->next)
1133 if(p->status.remove)
1136 if(p->status.dataopen)
1137 if(FD_ISSET(p->socket, f))
1140 The only thing that can happen to get us here is apparently an
1141 error on this outgoing(!) UDP socket that isn't immediate (i.e.
1142 something that will not trigger an error directly on send()).
1143 I've once got here when it said `No route to host'.
1145 getsockopt(p->socket, SOL_SOCKET, SO_ERROR, &x, &l);
1146 syslog(LOG_ERR, _("Outgoing data socket error for %s (%s): %s"),
1147 p->vpn_hostname, p->real_hostname, sys_errlist[x]);
1148 terminate_connection(p);
1153 if(FD_ISSET(p->meta_socket, f))
1154 if(handle_incoming_meta_data(p) < 0)
1156 terminate_connection(p);
1161 if(FD_ISSET(myself->socket, f))
1162 handle_incoming_vpn_data(myself);
1164 if(FD_ISSET(myself->meta_socket, f))
1165 handle_new_meta_connection(myself);
1170 read, encrypt and send data that is
1171 available through the ethertap device
1173 void handle_tap_input(void)
1177 int ether_type, lenin;
1179 memset(&vp, 0, sizeof(vp));
1180 if((lenin = read(tap_fd, &vp, MTU)) <= 0)
1182 syslog(LOG_ERR, _("Error while reading from tapdevice: %m"));
1186 total_tap_in += lenin;
1188 ether_type = ntohs(*((unsigned short*)(&vp.data[12])));
1189 if(ether_type != 0x0800)
1192 syslog(LOG_INFO, _("Non-IP ethernet frame %04x from " MAC_ADDR_S),
1193 ether_type, MAC_ADDR_V(vp.data[6]));
1200 syslog(LOG_INFO, _("Dropping short packet"));
1204 from = ntohl(*((unsigned long*)(&vp.data[26])));
1205 to = ntohl(*((unsigned long*)(&vp.data[30])));
1207 vp.len = (length_t)lenin - 2;
1209 strip_mac_addresses(&vp);
1211 send_packet(to, &vp);
1216 this is where it all happens...
1218 void main_loop(void)
1223 time_t last_ping_check;
1225 last_ping_check = time(NULL);
1229 tv.tv_sec = timeout;
1235 if((r = select(FD_SETSIZE, &fset, NULL, NULL, &tv)) < 0)
1237 if(errno != EINTR) /* because of alarm */
1239 syslog(LOG_ERR, _("Error while waiting for input: %m"));
1247 close_network_connections();
1249 if(read_config_file(configfilename))
1251 syslog(LOG_ERR, _("Unable to reread configuration file, exiting"));
1254 setup_network_connections();
1258 if(last_ping_check + timeout < time(NULL))
1259 /* Let's check if everybody is still alive */
1261 check_dead_connections();
1262 last_ping_check = time(NULL);
1267 check_network_activity(&fset);
1269 /* local tap data */
1270 if(FD_ISSET(tap_fd, &fset))