2 * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License v2 as published by
6 * the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
18 #include <sys/ioctl.h>
19 #include <sys/socket.h>
34 LIST_HEAD(interfaces);
37 static int host_timeout;
39 static int forward_bcast;
40 static int forward_dhcp;
42 static struct relayd_host *find_host_by_ipaddr(struct relayd_interface *rif, const uint8_t *ipaddr)
44 struct relayd_host *host;
47 list_for_each_entry(rif, &interfaces, list) {
48 host = find_host_by_ipaddr(rif, ipaddr);
57 list_for_each_entry(host, &rif->hosts, list) {
58 if (memcmp(ipaddr, host->ipaddr, sizeof(host->ipaddr)) != 0)
66 static void add_arp(struct relayd_host *host)
68 struct sockaddr_in *sin;
71 strncpy(arp.arp_dev, host->rif->ifname, sizeof(arp.arp_dev));
72 arp.arp_flags = ATF_COM;
74 arp.arp_ha.sa_family = ARPHRD_ETHER;
75 memcpy(arp.arp_ha.sa_data, host->lladdr, ETH_ALEN);
77 sin = (struct sockaddr_in *) &arp.arp_pa;
78 sin->sin_family = AF_INET;
79 memcpy(&sin->sin_addr, host->ipaddr, sizeof(host->ipaddr));
81 ioctl(inet_sock, SIOCSARP, &arp);
84 static void del_host(struct relayd_host *host)
86 DPRINTF(1, "%s: deleting host "IP_FMT" ("MAC_FMT")\n", host->rif->ifname,
87 IP_BUF(host->ipaddr), MAC_BUF(host->lladdr));
89 if (host->rif->managed)
90 relayd_del_route(host);
91 list_del(&host->list);
95 static void fill_arp_request(struct arp_packet *pkt, struct relayd_interface *rif,
96 uint8_t spa[4], uint8_t tpa[4])
98 memset(pkt, 0, sizeof(*pkt));
100 pkt->eth.ether_type = htons(ETHERTYPE_ARP);
101 memcpy(pkt->eth.ether_shost, rif->sll.sll_addr, ETH_ALEN);
103 memcpy(pkt->arp.arp_sha, rif->sll.sll_addr, ETH_ALEN);
104 memcpy(pkt->arp.arp_spa, spa, 4);
105 memcpy(pkt->arp.arp_tpa, tpa, 4);
107 pkt->arp.arp_hrd = htons(ARPHRD_ETHER);
108 pkt->arp.arp_pro = htons(ETH_P_IP);
109 pkt->arp.arp_hln = ETH_ALEN;
110 pkt->arp.arp_pln = 4;
113 static void send_arp_request(struct relayd_host *host)
115 struct relayd_interface *rif = host->rif;
116 struct arp_packet pkt;
118 fill_arp_request(&pkt, host->rif, host->rif->src_ip, host->ipaddr);
120 pkt.arp.arp_op = htons(ARPOP_REQUEST);
121 memcpy(pkt.arp.arp_spa, rif->src_ip, ETH_ALEN);
122 memset(pkt.arp.arp_tha, 0, ETH_ALEN);
123 memset(pkt.eth.ether_dhost, 0xff, ETH_ALEN);
125 DPRINTF(2, "%s: sending ARP who-has "IP_FMT", tell "IP_FMT" ("MAC_FMT")\n",
126 rif->ifname, IP_BUF(pkt.arp.arp_tpa),
127 IP_BUF(pkt.arp.arp_spa), MAC_BUF(pkt.eth.ether_shost));
129 sendto(rif->fd.fd, &pkt, sizeof(pkt), 0,
130 (struct sockaddr *) &rif->sll, sizeof(rif->sll));
133 static void send_arp_reply(struct relayd_interface *rif, uint8_t spa[4],
134 uint8_t tha[ETH_ALEN], uint8_t tpa[4])
136 struct arp_packet pkt;
138 fill_arp_request(&pkt, rif, spa, tpa);
140 pkt.arp.arp_op = htons(ARPOP_REPLY);
141 memcpy(pkt.eth.ether_dhost, tha, ETH_ALEN);
142 memcpy(pkt.arp.arp_tha, tha, ETH_ALEN);
144 DPRINTF(2, "%s: sending ARP reply to "IP_FMT", "IP_FMT" is at ("MAC_FMT")\n",
145 rif->ifname, IP_BUF(pkt.arp.arp_tpa),
146 IP_BUF(pkt.arp.arp_spa), MAC_BUF(pkt.eth.ether_shost));
148 sendto(rif->fd.fd, &pkt, sizeof(pkt), 0,
149 (struct sockaddr *) &rif->sll, sizeof(rif->sll));
152 static void host_entry_timeout(struct uloop_timeout *timeout)
154 struct relayd_host *host = container_of(timeout, struct relayd_host, timeout);
157 * When a host is behind a managed interface, we must not expire its host
158 * entry prematurely, as this will cause routes to the node to expire,
159 * leading to loss of connectivity from the other side.
160 * When the timeout is reached, try pinging the host a few times before
163 if (host->rif->managed && host->cleanup_pending < 2) {
164 send_arp_request(host);
165 host->cleanup_pending++;
166 uloop_timeout_set(&host->timeout, 1000);
172 static struct relayd_host *add_host(struct relayd_interface *rif, const uint8_t *lladdr, const uint8_t *ipaddr)
174 struct relayd_host *host;
176 DPRINTF(1, "%s: adding host "IP_FMT" ("MAC_FMT")\n", rif->ifname,
177 IP_BUF(ipaddr), MAC_BUF(lladdr));
179 host = calloc(1, sizeof(*host));
181 memcpy(host->ipaddr, ipaddr, sizeof(host->ipaddr));
182 memcpy(host->lladdr, lladdr, sizeof(host->lladdr));
183 list_add(&host->list, &rif->hosts);
184 host->timeout.cb = host_entry_timeout;
185 uloop_timeout_set(&host->timeout, host_timeout * 1000);
189 relayd_add_route(host);
194 struct relayd_host *relayd_refresh_host(struct relayd_interface *rif, const uint8_t *lladdr, const uint8_t *ipaddr)
196 struct relayd_host *host;
198 host = find_host_by_ipaddr(rif, ipaddr);
200 host = find_host_by_ipaddr(NULL, ipaddr);
203 * When we suddenly see the host appearing on a different interface,
204 * reduce the timeout to make the old entry expire faster, in case the
206 * If the old entry is behind a managed interface, it will be pinged
207 * before we expire it
209 if (host && !host->cleanup_pending)
210 uloop_timeout_set(&host->timeout, 1);
212 host = add_host(rif, lladdr, ipaddr);
214 host->cleanup_pending = false;
215 uloop_timeout_set(&host->timeout, host_timeout * 1000);
221 static void relay_arp_request(struct relayd_interface *from_rif, struct arp_packet *pkt)
223 struct relayd_interface *rif;
224 struct arp_packet reqpkt;
226 memcpy(&reqpkt, pkt, sizeof(reqpkt));
227 list_for_each_entry(rif, &interfaces, list) {
231 memcpy(reqpkt.eth.ether_shost, rif->sll.sll_addr, ETH_ALEN);
232 memcpy(reqpkt.arp.arp_sha, rif->sll.sll_addr, ETH_ALEN);
234 DPRINTF(2, "%s: sending ARP who-has "IP_FMT", tell "IP_FMT" ("MAC_FMT")\n",
235 rif->ifname, IP_BUF(reqpkt.arp.arp_tpa),
236 IP_BUF(reqpkt.arp.arp_spa), MAC_BUF(reqpkt.eth.ether_shost));
238 sendto(rif->fd.fd, &reqpkt, sizeof(reqpkt), 0,
239 (struct sockaddr *) &rif->sll, sizeof(rif->sll));
243 static void recv_arp_request(struct relayd_interface *rif, struct arp_packet *pkt)
245 struct relayd_host *host;
247 DPRINTF(2, "%s: ARP who-has "IP_FMT", tell "IP_FMT" ("MAC_FMT")\n",
249 IP_BUF(pkt->arp.arp_tpa),
250 IP_BUF(pkt->arp.arp_spa),
251 MAC_BUF(pkt->eth.ether_shost));
253 if (!memcmp(pkt->arp.arp_spa, "\x00\x00\x00\x00", 4))
256 relayd_refresh_host(rif, pkt->eth.ether_shost, pkt->arp.arp_spa);
258 host = find_host_by_ipaddr(NULL, pkt->arp.arp_tpa);
261 * If a host is being pinged because of a timeout, do not use the cached
262 * entry here. That way we can avoid giving out stale data in case the node
263 * has moved. We shouldn't relay requests here either, as we might miss our
264 * chance to create a host route.
266 if (host && host->cleanup_pending)
269 relay_arp_request(rif, pkt);
273 static void recv_arp_reply(struct relayd_interface *rif, struct arp_packet *pkt)
275 struct relayd_host *host;
277 DPRINTF(2, "%s: received ARP reply for "IP_FMT" from "MAC_FMT", deliver to "IP_FMT"\n",
279 IP_BUF(pkt->arp.arp_spa),
280 MAC_BUF(pkt->eth.ether_shost),
281 IP_BUF(pkt->arp.arp_tpa));
283 relayd_refresh_host(rif, pkt->arp.arp_sha, pkt->arp.arp_spa);
285 if (!memcmp(pkt->arp.arp_tpa, rif->src_ip, 4))
288 host = find_host_by_ipaddr(NULL, pkt->arp.arp_tpa);
292 if (host->rif == rif)
295 send_arp_reply(host->rif, pkt->arp.arp_spa, host->lladdr, host->ipaddr);
298 static void recv_packet(struct uloop_fd *fd, unsigned int events)
300 struct relayd_interface *rif = container_of(fd, struct relayd_interface, fd);
301 struct arp_packet *pkt;
302 static char pktbuf[4096];
309 pktlen = recv(rif->fd.fd, pktbuf, sizeof(pktbuf), 0);
320 pkt = (void *)pktbuf;
321 if (pkt->arp.arp_op == htons(ARPOP_REPLY))
322 recv_arp_reply(rif, pkt);
323 else if (pkt->arp.arp_op == htons(ARPOP_REQUEST))
324 recv_arp_request(rif, pkt);
326 DPRINTF(1, "received unknown packet type: %04x\n", ntohs(pkt->arp.arp_op));
331 static void forward_bcast_packet(struct relayd_interface *from_rif, void *packet, int len)
333 struct relayd_interface *rif;
334 struct ether_header *eth = packet;
336 list_for_each_entry(rif, &interfaces, list) {
340 DPRINTF(3, "%s: forwarding broadcast packet to %s\n", from_rif->ifname, rif->ifname);
341 memcpy(eth->ether_shost, rif->sll.sll_addr, ETH_ALEN);
342 send(rif->bcast_fd.fd, packet, len, 0);
347 chksum(uint16_t sum, const uint8_t *data, uint16_t len)
352 last = data + len - 1;
355 t = (data[0] << 8) + data[1];
363 t = (data[0] << 8) + 0;
372 static bool forward_dhcp_packet(struct relayd_interface *rif, void *data, int len)
374 struct ip_packet *pkt = data;
376 struct dhcp_header *dhcp;
380 if (pkt->eth.ether_type != htons(ETH_P_IP))
383 if (pkt->iph.version != 4)
386 if (pkt->iph.protocol != IPPROTO_UDP)
389 udp = (void *) ((char *) &pkt->iph + (pkt->iph.ihl << 2));
390 dhcp = (void *) (udp + 1);
392 udplen = ntohs(udp->len);
393 if (udplen > len - ((char *) udp - (char *) data))
396 if (udp->dest != htons(67) && udp->source != htons(67))
399 if (dhcp->op != 1 && dhcp->op != 2)
406 relayd_refresh_host(rif, pkt->eth.ether_shost, (void *) &pkt->iph.saddr);
408 DPRINTF(2, "%s: handling DHCP %s\n", rif->ifname, (dhcp->op == 1 ? "request" : "response"));
410 dhcp->flags |= htons(DHCP_FLAG_BROADCAST);
413 sum = udplen + IPPROTO_UDP;
414 sum = chksum(sum, (void *) &pkt->iph.saddr, 8);
415 sum = chksum(sum, (void *) udp, udplen);
419 udp->check = htons(~sum);
421 forward_bcast_packet(rif, data, len);
426 static void recv_bcast_packet(struct uloop_fd *fd, unsigned int events)
428 struct relayd_interface *rif = container_of(fd, struct relayd_interface, bcast_fd);
429 static char pktbuf[4096];
436 pktlen = recv(rif->bcast_fd.fd, pktbuf, sizeof(pktbuf), 0);
447 if (!forward_bcast && !forward_dhcp)
450 if (forward_dhcp_packet(rif, pktbuf, pktlen))
454 forward_bcast_packet(rif, pktbuf, pktlen);
459 static int init_interface(struct relayd_interface *rif)
461 struct sockaddr_ll *sll = &rif->sll;
462 struct sockaddr_in *sin;
465 #ifdef PACKET_RECV_TYPE
466 unsigned int pkt_type;
469 fd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ARP));
475 memset(&ifr, 0, sizeof(ifr));
476 strcpy(ifr.ifr_name, rif->ifname);
478 if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0) {
479 perror("ioctl(SIOCGIFHWADDR)");
483 memcpy(sll->sll_addr, ifr.ifr_hwaddr.sa_data, ETH_ALEN);
484 sll->sll_family = AF_PACKET;
485 sll->sll_protocol = htons(ETH_P_ARP);
486 sll->sll_pkttype = PACKET_BROADCAST;
487 sll->sll_hatype = ARPHRD_ETHER;
488 sll->sll_halen = ETH_ALEN;
490 if (ioctl(fd, SIOCGIFINDEX, &ifr) < 0) {
491 perror("ioctl(SIOCGIFINDEX)");
495 sll->sll_ifindex = ifr.ifr_ifindex;
497 if (ioctl(fd, SIOCGIFADDR, &ifr) < 0) {
498 memcpy(rif->src_ip, DUMMY_IP, sizeof(rif->src_ip));
500 sin = (struct sockaddr_in *) &ifr.ifr_addr;
501 memcpy(rif->src_ip, &sin->sin_addr.s_addr, sizeof(rif->src_ip));
504 if (bind(fd, (struct sockaddr *)sll, sizeof(struct sockaddr_ll)) < 0) {
505 perror("bind(ETH_P_ARP)");
509 rif->fd.cb = recv_packet;
510 uloop_fd_add(&rif->fd, ULOOP_READ | ULOOP_EDGE_TRIGGER);
512 if (!forward_bcast && !forward_dhcp)
515 fd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_IP));
519 rif->bcast_fd.fd = fd;
520 rif->bcast_fd.cb = recv_bcast_packet;
522 memcpy(&rif->bcast_sll, &rif->sll, sizeof(rif->bcast_sll));
523 sll = &rif->bcast_sll;
524 sll->sll_protocol = htons(ETH_P_IP);
526 if (bind(fd, (struct sockaddr *)sll, sizeof(struct sockaddr_ll)) < 0) {
527 perror("bind(ETH_P_IP)");
531 #ifdef PACKET_RECV_TYPE
532 pkt_type = (1 << PACKET_BROADCAST);
533 setsockopt(fd, SOL_PACKET, PACKET_RECV_TYPE, &pkt_type, sizeof(pkt_type));
536 uloop_fd_add(&rif->bcast_fd, ULOOP_READ | ULOOP_EDGE_TRIGGER);
540 static int init_interfaces(void)
542 struct relayd_interface *rif;
545 list_for_each_entry(rif, &interfaces, list) {
546 ret = init_interface(rif);
554 static void del_interface(struct relayd_interface *rif)
556 struct relayd_host *host, *htmp;
558 list_for_each_entry_safe(host, htmp, &rif->hosts, list) {
564 static void cleanup_interfaces(void)
566 struct relayd_interface *rif, *rtmp;
568 list_for_each_entry_safe(rif, rtmp, &interfaces, list) {
573 static int alloc_interface(const char *ifname, bool managed)
575 struct relayd_interface *rif;
577 if (strlen(ifname) >= IFNAMSIZ)
580 rif = calloc(1, sizeof(*rif));
584 INIT_LIST_HEAD(&rif->list);
585 INIT_LIST_HEAD(&rif->hosts);
586 strcpy(rif->ifname, ifname);
587 list_add(&rif->list, &interfaces);
588 rif->managed = managed;
593 static void die(int signo)
596 * When we hit SIGTERM, clean up interfaces directly, so that we
597 * won't leave our routing in an invalid state.
599 cleanup_interfaces();
603 static int usage(const char *progname)
605 fprintf(stderr, "Usage: %s <options>\n"
608 " -d Enable debug messages\n"
609 " -i <ifname> Add an interface for relaying\n"
610 " -I <ifname> Same as -i, except with ARP cache and host route management\n"
611 " You need to specify at least two interfaces\n"
612 " -t <timeout> Host entry expiry timeout\n"
613 " -B Enable broadcast forwarding\n"
614 " -D Enable DHCP forwarding\n"
620 int main(int argc, char **argv)
627 inet_sock = socket(AF_INET, SOCK_DGRAM, 0);
629 perror("socket(AF_INET)");
637 while ((ch = getopt(argc, argv, "I:i:t:BDd")) != -1) {
644 if (alloc_interface(optarg, managed) < 0)
650 host_timeout = atoi(optarg);
651 if (host_timeout <= 0)
652 return usage(argv[0]);
665 return usage(argv[0]);
669 if (list_empty(&interfaces))
670 return usage(argv[0]);
673 fprintf(stderr, "ERROR: Need at least 2 interfaces for relaying\n");
680 signal(SIGTERM, die);
682 signal(SIGUSR1, die);
683 signal(SIGUSR2, die);
685 if (init_interfaces() < 0)
688 if (relayd_rtnl_init() < 0)
694 cleanup_interfaces();