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 1.35.4.2 2000/06/24 12:35:42 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 static int seconds_till_retry;
61 /* The global list of existing connections */
62 conn_list_t *conn_list = NULL;
63 conn_list_t *myself = NULL;
66 strip off the MAC adresses of an ethernet frame
68 void strip_mac_addresses(vpn_packet_t *p)
70 unsigned char tmp[MAXSIZE];
72 memcpy(tmp, p->data, p->len);
74 memcpy(p->data, &tmp[12], p->len);
79 reassemble MAC addresses
81 void add_mac_addresses(vpn_packet_t *p)
83 unsigned char tmp[MAXSIZE];
85 memcpy(&tmp[12], p->data, p->len);
87 tmp[0] = tmp[6] = 0xfe;
88 tmp[1] = tmp[7] = 0xfd;
89 *((ip_t*)(&tmp[2])) = (ip_t)(htonl(myself->vpn_ip));
90 *((ip_t*)(&tmp[8])) = *((ip_t*)(&tmp[26]));
91 memcpy(p->data, &tmp[0], p->len);
95 int xsend(conn_list_t *cl, void *packet)
100 do_encrypt((vpn_packet_t*)packet, &rp, cl->key);
101 rp.from = htonl(myself->vpn_ip);
102 rp.data.len = htons(rp.data.len);
103 rp.len = htons(rp.len);
106 syslog(LOG_ERR, _("Sent %d bytes to %lx"), ntohs(rp.len), cl->vpn_ip);
108 if((r = send(cl->socket, (char*)&rp, ntohs(rp.len), 0)) < 0)
110 syslog(LOG_ERR, _("Error sending data: %m"));
114 total_socket_out += r;
121 int xrecv(conn_list_t *cl, void *packet)
126 do_decrypt((real_packet_t*)packet, &vp, cl->key);
127 add_mac_addresses(&vp);
129 if((lenin = write(tap_fd, &vp, vp.len + sizeof(vp.len))) < 0)
130 syslog(LOG_ERR, _("Can't write to tap device: %m"));
132 total_tap_out += lenin;
135 cl->last_ping_time = time(NULL);
141 add the given packet of size s to the
142 queue q, be it the send or receive queue
144 void add_queue(packet_queue_t **q, void *packet, size_t s)
149 syslog(LOG_DEBUG, _("packet to queue: %d"), s);
151 e = xmalloc(sizeof(*e));
152 e->packet = xmalloc(s);
153 memcpy(e->packet, packet, s);
157 *q = xmalloc(sizeof(**q));
158 (*q)->head = (*q)->tail = NULL;
161 e->next = NULL; /* We insert at the tail */
163 if((*q)->tail) /* Do we have a tail? */
165 (*q)->tail->next = e;
166 e->prev = (*q)->tail;
168 else /* No tail -> no head too */
178 /* Remove a queue element */
179 void del_queue(packet_queue_t **q, queue_element_t *e)
184 if(e->next) /* There is a successor, so we are not tail */
186 if(e->prev) /* There is a predecessor, so we are not head */
188 e->next->prev = e->prev;
189 e->prev->next = e->next;
191 else /* We are head */
193 e->next->prev = NULL;
194 (*q)->head = e->next;
197 else /* We are tail (or all alone!) */
199 if(e->prev) /* We are not alone :) */
201 e->prev->next = NULL;
202 (*q)->tail = e->prev;
216 flush a queue by calling function for
217 each packet, and removing it when that
218 returned a zero exit code
220 void flush_queue(conn_list_t *cl, packet_queue_t **pq,
221 int (*function)(conn_list_t*,void*))
223 queue_element_t *p, *next = NULL;
225 for(p = (*pq)->head; p != NULL; )
229 if(!function(cl, p->packet))
236 syslog(LOG_DEBUG, _("queue flushed"));
241 flush the send&recv queues
242 void because nothing goes wrong here, packets
243 remain in the queue if something goes wrong
245 void flush_queues(conn_list_t *cl)
251 syslog(LOG_DEBUG, _("Flushing send queue for " IP_ADDR_S),
252 IP_ADDR_V(cl->vpn_ip));
253 flush_queue(cl, &(cl->sq), xsend);
259 syslog(LOG_DEBUG, _("Flushing receive queue for " IP_ADDR_S),
260 IP_ADDR_V(cl->vpn_ip));
261 flush_queue(cl, &(cl->rq), xrecv);
267 send a packet to the given vpn ip.
269 int send_packet(ip_t to, vpn_packet_t *packet)
273 if((cl = lookup_conn(to)) == NULL)
277 syslog(LOG_NOTICE, _("trying to look up " IP_ADDR_S " in connection list failed."),
281 /* Is this really necessary? If we can't find "to", then neither should any uplink. (GS) */
285 for(cl = conn_list; cl != NULL && !cl->status.outgoing; cl = cl->next);
287 { /* No open outgoing connection has been found. */
289 syslog(LOG_NOTICE, _("There is no remote host I can send this packet to."));
294 /* If we ourselves have indirectdata flag set, we should send only to our uplink! */
296 if(myself->flags & EXPORTINDIRECTDATA)
298 for(cl = conn_list; cl != NULL && !cl->status.outgoing; cl = cl->next);
300 { /* No open outgoing connection has been found. */
302 syslog(LOG_NOTICE, _("There is no remote host I can send this packet to."));
308 /* If indirectdata flag is set for the destination we just looked up,
309 * then real_ip is actually the vpn_ip of the gateway tincd
313 if(cl->flags & INDIRECTDATA)
315 if((cl = lookup_conn(cl->vpn_ip)) == NULL)
319 syslog(LOG_NOTICE, _("indirect look up " IP_ADDR_S " in connection list failed."),
323 /* Gateway tincd dead? Should we kill it? (GS) */
327 if(cl->flags & INDIRECTDATA) /* This should not happen */
330 syslog(LOG_NOTICE, _("double indirection for " IP_ADDR_S),
336 if(my_key_expiry <= time(NULL))
339 if(!cl->status.dataopen)
340 if(setup_vpn_connection(cl) < 0)
343 if(!cl->status.validkey)
345 add_queue(&(cl->sq), packet, packet->len + 2);
346 if(!cl->status.waitingforkey)
347 send_key_request(cl->vpn_ip); /* Keys should be sent to the host running the tincd */
351 if(!cl->status.active)
353 add_queue(&(cl->sq), packet, packet->len + 2);
355 syslog(LOG_INFO, _(IP_ADDR_S " is not ready, queueing packet."), IP_ADDR_V(cl->vpn_ip));
356 return 0; /* We don't want to mess up, do we? */
359 /* can we send it? can we? can we? huh? */
361 return xsend(cl, packet);
365 open the local ethertap device
367 int setup_tap_fd(void)
370 const char *tapfname;
373 if((cfg = get_config_val(tapdevice)) == NULL)
374 tapfname = "/dev/tap0";
376 tapfname = cfg->data.ptr;
378 if((nfd = open(tapfname, O_RDWR | O_NONBLOCK)) < 0)
380 syslog(LOG_ERR, _("Could not open %s: %m"), tapfname);
390 set up the socket that we listen on for incoming
393 int setup_listen_meta_socket(int port)
396 struct sockaddr_in a;
399 if((nfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
401 syslog(LOG_ERR, _("Creating metasocket failed: %m"));
405 if(setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)))
407 syslog(LOG_ERR, _("setsockopt: %m"));
411 flags = fcntl(nfd, F_GETFL);
412 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0)
414 syslog(LOG_ERR, _("fcntl: %m"));
418 memset(&a, 0, sizeof(a));
419 a.sin_family = AF_INET;
420 a.sin_port = htons(port);
421 a.sin_addr.s_addr = htonl(INADDR_ANY);
423 if(bind(nfd, (struct sockaddr *)&a, sizeof(struct sockaddr)))
425 syslog(LOG_ERR, _("Can't bind to port %hd/tcp: %m"), port);
431 syslog(LOG_ERR, _("listen: %m"));
439 setup the socket for incoming encrypted
442 int setup_vpn_in_socket(int port)
445 struct sockaddr_in a;
448 if((nfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
450 syslog(LOG_ERR, _("Creating socket failed: %m"));
454 if(setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)))
456 syslog(LOG_ERR, _("setsockopt: %m"));
460 flags = fcntl(nfd, F_GETFL);
461 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0)
463 syslog(LOG_ERR, _("fcntl: %m"));
467 memset(&a, 0, sizeof(a));
468 a.sin_family = AF_INET;
469 a.sin_port = htons(port);
470 a.sin_addr.s_addr = htonl(INADDR_ANY);
472 if(bind(nfd, (struct sockaddr *)&a, sizeof(struct sockaddr)))
474 syslog(LOG_ERR, _("Can't bind to port %hd/udp: %m"), port);
482 setup an outgoing meta (tcp) socket
484 int setup_outgoing_meta_socket(conn_list_t *cl)
487 struct sockaddr_in a;
490 if((cfg = get_config_val(upstreamport)) == NULL)
493 cl->port = cfg->data.val;
495 cl->meta_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
496 if(cl->meta_socket == -1)
498 syslog(LOG_ERR, _("Creating socket failed: %m"));
502 a.sin_family = AF_INET;
503 a.sin_port = htons(cl->port);
504 a.sin_addr.s_addr = htonl(cl->real_ip);
506 if(connect(cl->meta_socket, (struct sockaddr *)&a, sizeof(a)) == -1)
508 syslog(LOG_ERR, _(IP_ADDR_S ":%d: %m"), IP_ADDR_V(cl->real_ip), cl->port);
512 flags = fcntl(cl->meta_socket, F_GETFL);
513 if(fcntl(cl->meta_socket, F_SETFL, flags | O_NONBLOCK) < 0)
515 syslog(LOG_ERR, _("fcntl: %m"));
519 cl->hostname = hostlookup(htonl(cl->real_ip));
521 syslog(LOG_INFO, _("Connected to %s:%hd"), cl->hostname, cl->port);
527 setup an outgoing connection. It's not
528 necessary to also open an udp socket as
529 well, because the other host will initiate
530 an authentication sequence during which
531 we will do just that.
533 int setup_outgoing_connection(ip_t ip)
537 ncn = new_conn_list();
540 if(setup_outgoing_meta_socket(ncn) < 0)
542 syslog(LOG_ERR, _("Could not set up a meta connection."));
543 free_conn_element(ncn);
547 ncn->status.meta = 1;
548 ncn->status.outgoing = 1;
549 ncn->next = conn_list;
556 set up the local sockets (listen only)
558 int setup_myself(void)
562 myself = new_conn_list();
564 if(!(cfg = get_config_val(myvpnip)))
566 syslog(LOG_ERR, _("No value for my VPN IP given"));
570 myself->vpn_ip = cfg->data.ip->ip;
571 myself->vpn_mask = cfg->data.ip->mask;
574 if(!(cfg = get_config_val(listenport)))
577 myself->port = cfg->data.val;
579 if(cfg = get_config_val(indirectdata))
581 myself->flags |= EXPORTINDIRECTDATA;
583 if((myself->meta_socket = setup_listen_meta_socket(myself->port)) < 0)
585 syslog(LOG_ERR, _("Unable to set up a listening socket"));
589 if((myself->socket = setup_vpn_in_socket(myself->port)) < 0)
591 syslog(LOG_ERR, _("Unable to set up an incoming vpn data socket"));
592 close(myself->meta_socket);
596 myself->status.active = 1;
598 syslog(LOG_NOTICE, _("Ready: listening on port %d."), myself->port);
604 sigalrm_handler(int a)
608 cfg = get_config_val(upstreamip);
610 if(!setup_outgoing_connection(cfg->data.ip->ip))
612 signal(SIGALRM, SIG_IGN);
616 signal(SIGALRM, sigalrm_handler);
617 seconds_till_retry += 5;
618 if(seconds_till_retry>300) /* Don't wait more than 5 minutes. */
619 seconds_till_retry = 300;
620 alarm(seconds_till_retry);
621 syslog(LOG_ERR, _("Still failed to connect to other. Will retry in %d seconds."),
628 setup all initial network connections
630 int setup_network_connections(void)
634 if((cfg = get_config_val(pingtimeout)) == NULL)
637 timeout = cfg->data.val;
639 if(setup_tap_fd() < 0)
642 if(setup_myself() < 0)
645 if((cfg = get_config_val(upstreamip)) == NULL)
646 /* No upstream IP given, we're listen only. */
649 if(setup_outgoing_connection(cfg->data.ip->ip))
651 signal(SIGALRM, sigalrm_handler);
652 seconds_till_retry = 300;
653 alarm(seconds_till_retry);
654 syslog(LOG_NOTICE, _("Try to re-establish outgoing connection in 5 minutes."));
661 close all open network connections
663 void close_network_connections(void)
667 for(p = conn_list; p != NULL; p = p->next)
669 if(p->status.dataopen)
671 shutdown(p->socket, 0); /* No more receptions */
677 shutdown(p->meta_socket, 0); /* No more receptions */
678 close(p->meta_socket);
683 if(myself->status.active)
685 close(myself->meta_socket);
686 close(myself->socket);
692 syslog(LOG_NOTICE, _("Terminating."));
698 create a data (udp) socket
700 int setup_vpn_connection(conn_list_t *cl)
703 struct sockaddr_in a;
706 syslog(LOG_DEBUG, _("Opening UDP socket to " IP_ADDR_S), IP_ADDR_V(cl->real_ip));
708 nfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
711 syslog(LOG_ERR, _("Creating data socket failed: %m"));
715 a.sin_family = AF_INET;
716 a.sin_port = htons(cl->port);
717 a.sin_addr.s_addr = htonl(cl->real_ip);
719 if(connect(nfd, (struct sockaddr *)&a, sizeof(a)) == -1)
721 syslog(LOG_ERR, _("Connecting to " IP_ADDR_S ":%d failed: %m"),
722 IP_ADDR_V(cl->real_ip), cl->port);
726 flags = fcntl(nfd, F_GETFL);
727 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0)
729 syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%m"), __FILE__, __LINE__, nfd);
734 cl->status.dataopen = 1;
740 handle an incoming tcp connect call and open
743 conn_list_t *create_new_connection(int sfd)
746 struct sockaddr_in ci;
747 int len = sizeof(ci);
751 if(getpeername(sfd, &ci, &len) < 0)
753 syslog(LOG_ERR, _("Error: getpeername: %m"));
757 p->hostname = hostlookup(ci.sin_addr.s_addr);
758 p->real_ip = ntohl(ci.sin_addr.s_addr);
759 p->meta_socket = sfd;
762 p->last_ping_time = time(NULL);
765 syslog(LOG_NOTICE, _("Connection from %s:%d"), p->hostname, htons(ci.sin_port));
767 if(send_basic_info(p) < 0)
777 put all file descriptors in an fd_set array
779 void build_fdset(fd_set *fs)
785 for(p = conn_list; p != NULL; p = p->next)
788 FD_SET(p->meta_socket, fs);
789 if(p->status.dataopen)
790 FD_SET(p->socket, fs);
793 FD_SET(myself->meta_socket, fs);
794 FD_SET(myself->socket, fs);
800 receive incoming data from the listening
801 udp socket and write it to the ethertap
802 device after being decrypted
804 int handle_incoming_vpn_data(conn_list_t *cl)
808 int x, l = sizeof(x);
811 if(getsockopt(cl->socket, SOL_SOCKET, SO_ERROR, &x, &l) < 0)
813 syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%m"), __FILE__, __LINE__, cl->socket);
818 syslog(LOG_ERR, _("Incoming data socket error: %s"), sys_errlist[x]);
823 lenin = recvfrom(cl->socket, &rp, MTU, 0, NULL, NULL);
826 syslog(LOG_ERR, _("Receiving data failed: %m"));
829 total_socket_in += lenin;
831 rp.data.len = ntohs(rp.data.len);
832 rp.len = ntohs(rp.len);
833 rp.from = ntohl(rp.from);
837 f = lookup_conn(rp.from);
839 syslog(LOG_DEBUG, _("packet from " IP_ADDR_S " (len %d)"),
840 IP_ADDR_V(rp.from), rp.len);
843 syslog(LOG_ERR, _("Got packet from unknown source " IP_ADDR_S),
848 if(f->status.validkey)
852 add_queue(&(f->rq), &rp, rp.len);
853 if(!cl->status.waitingforkey)
854 send_key_request(rp.from);
857 if(my_key_expiry <= time(NULL))
865 terminate a connection and notify the other
866 end before closing the sockets
868 void terminate_connection(conn_list_t *cl)
873 if(cl->status.remove)
877 syslog(LOG_NOTICE, _("Closing connection with %s."), cl->hostname);
879 if(cl->status.timeout)
881 else if(!cl->status.termreq)
886 close(cl->meta_socket);
888 if(cl->status.outgoing)
890 signal(SIGALRM, sigalrm_handler);
891 seconds_till_retry = 5;
892 alarm(seconds_till_retry);
893 syslog(LOG_NOTICE, _("Try to re-establish outgoing connection in 5 seconds."));
896 cl->status.active = 0;
897 cl->status.remove = 1;
900 /* Find all connections that were lost because they were behind cl
901 (the connection that was dropped). */
902 for(p = conn_list; p != NULL; p = p->next)
905 p->status.active = 0;
906 p->status.remove = 1;
910 /* Then send a notification about all these connections to all hosts
911 that are still connected to us. */
912 for(p = conn_list; p != NULL; p = p->next)
913 if(!p->status.remove && p->status.meta)
914 for(q = conn_list; q != NULL; q = q->next)
922 Check if the other end is active.
923 If we have sent packets, but didn't receive any,
924 then possibly the other end is dead. We send a
925 PING request over the meta connection. If the other
926 end does not reply in time, we consider them dead
927 and close the connection.
929 int check_dead_connections(void)
935 for(p = conn_list; p != NULL; p = p->next)
939 if(p->status.active && p->status.meta)
941 if(p->last_ping_time + timeout < now)
943 if(p->status.pinged && !p->status.got_pong)
945 syslog(LOG_INFO, _("%s (" IP_ADDR_S ") didn't respond to ping"),
946 p->hostname, IP_ADDR_V(p->vpn_ip));
947 p->status.timeout = 1;
948 terminate_connection(p);
950 else if(p->want_ping)
953 p->last_ping_time = now;
954 p->status.pinged = 1;
955 p->status.got_pong = 0;
965 accept a new tcp connect and create a
968 int handle_new_meta_connection(conn_list_t *cl)
971 struct sockaddr client;
972 int nfd, len = sizeof(client);
974 if((nfd = accept(cl->meta_socket, &client, &len)) < 0)
976 syslog(LOG_ERR, _("Accepting a new connection failed: %m"));
980 if((ncn = create_new_connection(nfd)) == NULL)
984 syslog(LOG_NOTICE, _("Closed attempted connection."));
988 ncn->status.meta = 1;
989 ncn->next = conn_list;
996 dispatch any incoming meta requests
998 int handle_incoming_meta_data(conn_list_t *cl)
1000 int x, l = sizeof(x);
1001 int request, oldlen, i;
1004 if(getsockopt(cl->meta_socket, SOL_SOCKET, SO_ERROR, &x, &l) < 0)
1006 syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%m"), __FILE__, __LINE__, cl->meta_socket);
1011 syslog(LOG_ERR, _("Metadata socket error: %s"), sys_errlist[x]);
1015 if(cl->buflen >= MAXBUFSIZE)
1017 syslog(LOG_ERR, _("Metadata read buffer overflow."));
1021 lenin = read(cl->meta_socket, cl->buffer, MAXBUFSIZE-cl->buflen);
1025 syslog(LOG_ERR, _("Metadata socket read error: %m"));
1029 oldlen = cl->buflen;
1030 cl->buflen += lenin;
1036 for(i = oldlen; i < cl->buflen; i++)
1038 if(cl->buffer[i] == '\n')
1040 cl->buffer[i] = 0; /* replace end-of-line by end-of-string so we can use sscanf */
1048 if(sscanf(cl->buffer, "%d", &request) == 1)
1050 if((request < 0) || (request > 255) || (request_handlers[request] == NULL))
1052 syslog(LOG_ERR, _("Unknown request: %s"), cl->buffer);
1057 syslog(LOG_DEBUG, _("Got request: %s"), cl->buffer);
1059 if(request_handlers[request](cl)) /* Something went wrong. Probably scriptkiddies. Terminate. */
1061 syslog(LOG_ERR, _("Error while processing request from " IP_ADDR_S), IP_ADDR_V(cl->real_ip));
1067 syslog(LOG_ERR, _("Bogus data received."));
1071 cl->buflen -= cl->reqlen;
1072 memmove(cl->buffer, cl->buffer + cl->reqlen, cl->buflen);
1081 cl->last_ping_time = time(NULL);
1088 check all connections to see if anything
1089 happened on their sockets
1091 void check_network_activity(fd_set *f)
1094 int x, l = sizeof(x);
1096 for(p = conn_list; p != NULL; p = p->next)
1098 if(p->status.remove)
1101 if(p->status.dataopen)
1102 if(FD_ISSET(p->socket, f))
1105 The only thing that can happen to get us here is apparently an
1106 error on this outgoing(!) UDP socket that isn't immediate (i.e.
1107 something that will not trigger an error directly on send()).
1108 I've once got here when it said `No route to host'.
1110 getsockopt(p->socket, SOL_SOCKET, SO_ERROR, &x, &l);
1111 syslog(LOG_ERR, _("Outgoing data socket error: %s"), sys_errlist[x]);
1112 terminate_connection(p);
1117 if(FD_ISSET(p->meta_socket, f))
1118 if(handle_incoming_meta_data(p) < 0)
1120 terminate_connection(p);
1125 if(FD_ISSET(myself->socket, f))
1126 handle_incoming_vpn_data(myself);
1128 if(FD_ISSET(myself->meta_socket, f))
1129 handle_new_meta_connection(myself);
1134 read, encrypt and send data that is
1135 available through the ethertap device
1137 void handle_tap_input(void)
1141 int ether_type, lenin;
1143 memset(&vp, 0, sizeof(vp));
1144 if((lenin = read(tap_fd, &vp, MTU)) <= 0)
1146 syslog(LOG_ERR, _("Error while reading from tapdevice: %m"));
1150 total_tap_in += lenin;
1152 ether_type = ntohs(*((unsigned short*)(&vp.data[12])));
1153 if(ether_type != 0x0800)
1156 syslog(LOG_INFO, _("Non-IP ethernet frame %04x from " MAC_ADDR_S),
1157 ether_type, MAC_ADDR_V(vp.data[6]));
1164 syslog(LOG_INFO, _("Dropping short packet"));
1168 from = ntohl(*((unsigned long*)(&vp.data[26])));
1169 to = ntohl(*((unsigned long*)(&vp.data[30])));
1172 syslog(LOG_DEBUG, _("An IP packet (%04x) for " IP_ADDR_S " from " IP_ADDR_S),
1173 ether_type, IP_ADDR_V(to), IP_ADDR_V(from));
1175 syslog(LOG_DEBUG, _(MAC_ADDR_S " to " MAC_ADDR_S),
1176 MAC_ADDR_V(vp.data[0]), MAC_ADDR_V(vp.data[6]));
1178 vp.len = (length_t)lenin - 2;
1180 strip_mac_addresses(&vp);
1182 send_packet(to, &vp);
1187 this is where it all happens...
1189 void main_loop(void)
1194 time_t last_ping_check;
1196 last_ping_check = time(NULL);
1200 tv.tv_sec = timeout;
1206 if((r = select(FD_SETSIZE, &fset, NULL, NULL, &tv)) < 0)
1208 if(errno == EINTR) /* because of alarm */
1210 syslog(LOG_ERR, _("Error while waiting for input: %m"));
1214 if(last_ping_check + timeout < time(NULL))
1215 /* Let's check if everybody is still alive */
1217 check_dead_connections();
1218 last_ping_check = time(NULL);
1222 check_network_activity(&fset);
1224 /* local tap data */
1225 if(FD_ISSET(tap_fd, &fset))