2 discovery.c -- local network discovery
3 Copyright (C) 2014-2021 Guus Sliepen <guus@meshlink.io>
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License along
16 with this program; if not, write to the Free Software Foundation, Inc.,
17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
20 #define __APPLE_USE_RFC_3542
23 #if defined(__APPLE__)
24 #include <CoreFoundation/CoreFoundation.h>
25 #include <CoreFoundation/CFArray.h>
26 #include <CoreFoundation/CFString.h>
27 #include <SystemConfiguration/SystemConfiguration.h>
29 #include <netinet/in.h>
30 #elif defined(__unix) && !defined(__linux)
32 #include <net/route.h>
33 #include <netinet/in.h>
34 #elif defined(__linux)
35 #include <asm/types.h>
37 #include <linux/if_link.h>
38 #include <linux/netlink.h>
39 #include <linux/rtnetlink.h>
43 #include "meshlink_internal.h"
45 #include "discovery.h"
50 #include "connection.h"
54 #define MESHLINK_MDNS_SERVICE_TYPE "_%s._tcp"
55 #define MESHLINK_MDNS_NAME_KEY "name"
56 #define MESHLINK_MDNS_FINGERPRINT_KEY "fingerprint"
59 #define MSG_NOSIGNAL 0
62 #ifndef IPV6_ADD_MEMBERSHIP
63 #define IPV6_ADD_MEMBERSHIP IPV6_JOIN_GROUP
66 #ifndef IPV6_DROP_MEMBERSHIP
67 #define IPV6_DROP_MEMBERSHIP IPV6_LEAVE_GROUP
70 static const sockaddr_t mdns_address_ipv4 = {
71 .in.sin_family = AF_INET,
72 .in.sin_addr.s_addr = 0xfb0000e0,
73 .in.sin_port = 0xe914,
76 static const sockaddr_t mdns_address_ipv6 = {
77 .in6.sin6_family = AF_INET6,
78 .in6.sin6_addr.s6_addr[0x0] = 0xfd,
79 .in6.sin6_addr.s6_addr[0x1] = 0x02,
80 .in6.sin6_addr.s6_addr[0xf] = 0xfb,
81 .in6.sin6_port = 0xe914,
84 typedef struct discovery_address {
88 } discovery_address_t;
90 static int iface_compare(const void *va, const void *vb) {
96 static int address_compare(const void *va, const void *vb) {
97 const discovery_address_t *a = va;
98 const discovery_address_t *b = vb;
100 if(a->index != b->index) {
101 return a->index - b->index;
104 return sockaddrcmp_noport(&a->address, &b->address);
107 static void send_mdns_packet_ipv4(meshlink_handle_t *mesh, int fd, int index, const sockaddr_t *src, const sockaddr_t *dest, void *data, size_t len) {
114 struct in_pktinfo pkti = {
115 .ipi_ifindex = index,
116 .ipi_addr = src->in.sin_addr,
120 char buf[CMSG_SPACE(sizeof(pkti))];
121 struct cmsghdr align;
124 memset(&u, 0, sizeof(u));
126 struct msghdr msg = {
127 .msg_name = (struct sockaddr *) &dest->sa,
128 .msg_namelen = SALEN(dest->sa),
131 .msg_control = u.buf,
132 .msg_controllen = sizeof(u.buf),
135 struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
136 cmsg->cmsg_level = IPPROTO_IP;
137 cmsg->cmsg_type = IP_PKTINFO;
138 cmsg->cmsg_len = CMSG_LEN(sizeof(pkti));
139 memcpy(CMSG_DATA(cmsg), &pkti, sizeof(pkti));
142 ssize_t result = sendmsg(fd, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
148 ssize_t result = sendto(fd, data, len, MSG_DONTWAIT | MSG_NOSIGNAL, &dest->sa, SALEN(dest->sa));
152 logger(mesh, MESHLINK_ERROR, "Error sending multicast packet: %s", strerror(errno));
156 static void send_mdns_packet_ipv6(meshlink_handle_t *mesh, int fd, int index, const sockaddr_t *src, const sockaddr_t *dest, void *data, size_t len) {
163 struct in6_pktinfo pkti = {
164 .ipi6_ifindex = index,
165 .ipi6_addr = src->in6.sin6_addr,
169 char buf[CMSG_SPACE(sizeof(pkti))];
170 struct cmsghdr align;
173 memset(&u, 0, sizeof u);
175 struct msghdr msg = {
176 .msg_name = (struct sockaddr *) &dest->sa,
177 .msg_namelen = SALEN(dest->sa),
180 .msg_control = u.buf,
181 .msg_controllen = CMSG_LEN(sizeof(pkti)),
184 struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
185 cmsg->cmsg_level = IPPROTO_IPV6;
186 cmsg->cmsg_type = IPV6_PKTINFO;
187 cmsg->cmsg_len = CMSG_LEN(sizeof(pkti));
188 memcpy(CMSG_DATA(cmsg), &pkti, sizeof(pkti));
191 ssize_t result = sendmsg(fd, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
197 ssize_t result = sendto(fd, data, len, MSG_DONTWAIT | MSG_NOSIGNAL, &dest->sa, SALEN(dest->sa));
201 logger(mesh, MESHLINK_ERROR, "Error sending multicast packet: %s", strerror(errno));
205 static void send_mdns_packet(meshlink_handle_t *mesh, const discovery_address_t *addr) {
206 // Configure the socket to send the packet to the right interface
208 uint8_t request[1024], response[1024];
209 char *fingerprint = meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self);
210 const char *keys[] = {MESHLINK_MDNS_NAME_KEY, MESHLINK_MDNS_FINGERPRINT_KEY};
211 const char *values[] = {mesh->name, fingerprint};
212 size_t request_size = prepare_request(request, sizeof request, mesh->appname, "tcp");
213 size_t response_size = prepare_response(response, sizeof response, fingerprint, mesh->appname, "tcp", atoi(mesh->myport), 2, keys, values);
216 switch(addr->address.sa.sa_family) {
218 fd = mesh->discovery.sockets[0].fd;
219 #ifdef IP_MULTICAST_IF
221 struct ip_mreqn mreq = {
222 .imr_address = addr->address.in.sin_addr,
223 .imr_ifindex = addr->index,
226 if(setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF, &mreq, sizeof(mreq)) != 0) {
227 logger(mesh, MESHLINK_ERROR, "Could not set outgoing multicast interface on IPv4 socket");
234 send_mdns_packet_ipv4(mesh, fd, addr->index, &addr->address, &mdns_address_ipv4, request, request_size);
235 send_mdns_packet_ipv4(mesh, fd, addr->index, &addr->address, &mdns_address_ipv4, response, response_size);
239 fd = mesh->discovery.sockets[1].fd;
240 #ifdef IPV6_MULTICAST_IF
242 if(setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &addr->index, sizeof(addr->index)) != 0) {
243 logger(mesh, MESHLINK_ERROR, "Could not set outgoing multicast interface on IPv6 socket");
249 send_mdns_packet_ipv6(mesh, fd, addr->index, &addr->address, &mdns_address_ipv6, request, request_size);
250 send_mdns_packet_ipv6(mesh, fd, addr->index, &addr->address, &mdns_address_ipv6, response, response_size);
258 static void mdns_io_handler(event_loop_t *loop, void *data, int flags) {
260 meshlink_handle_t *mesh = loop->data;
264 socklen_t sl = sizeof(sa);
266 ssize_t len = recvfrom(io->fd, buf, sizeof(buf), MSG_DONTWAIT, &sa.sa, &sl);
269 if(!sockwouldblock(errno)) {
270 logger(mesh, MESHLINK_ERROR, "Error reading from mDNS discovery socket: %s", strerror(errno));
279 const char *keys[2] = {MESHLINK_MDNS_NAME_KEY, MESHLINK_MDNS_FINGERPRINT_KEY};
280 char *values[2] = {NULL, NULL};
282 if(parse_response(buf, len, &name, mesh->appname, "tcp", &port, 2, keys, values)) {
283 node_t *n = (node_t *)meshlink_get_node(mesh, values[0]);
286 if(n != mesh->self) {
287 logger(mesh, MESHLINK_INFO, "Node %s discovered on the local network.\n", n->name);
290 switch(sa.sa.sa_family) {
292 sa.in.sin_port = htons(port);
296 sa.in6.sin6_port = htons(port);
300 logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", n->name);
301 sa.sa.sa_family = AF_UNKNOWN;
305 if(sa.sa.sa_family != AF_UNKNOWN) {
306 n->catta_address = sa;
307 n->last_connect_try = 0;
308 node_add_recent_address(mesh, n, &sa);
311 n->connection->last_ping_time = -3600;
314 for list_each(outgoing_t, outgoing, mesh->outgoings) {
315 if(outgoing->node != n) {
319 outgoing->timeout = 0;
321 if(outgoing->ev.cb) {
322 timeout_set(&mesh->loop, &outgoing->ev, &(struct timespec) {
329 } else if(parse_request(buf, len, mesh->appname, "tcp")) {
330 // Send a unicast response back
331 char *fingerprint = meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self);
332 const char *response_values[] = {mesh->name, fingerprint};
333 size_t size = prepare_response(buf, sizeof(buf), fingerprint, mesh->appname, "tcp", atoi(mesh->myport), 2, keys, response_values);
334 sendto(io->fd, buf, size, MSG_DONTWAIT | MSG_NOSIGNAL, &sa.sa, sl);
340 for(int i = 0; i < 2; i++) {
345 static void iface_up(meshlink_handle_t *mesh, int index) {
346 int *p = bsearch(&index, mesh->discovery.ifaces, mesh->discovery.iface_count, sizeof(*p), iface_compare);
352 mesh->discovery.ifaces = xrealloc(mesh->discovery.ifaces, ++mesh->discovery.iface_count * sizeof(*p));
353 mesh->discovery.ifaces[mesh->discovery.iface_count - 1] = index;
354 qsort(mesh->discovery.ifaces, mesh->discovery.iface_count, sizeof(*p), iface_compare);
356 // Add multicast membership
357 struct ip_mreqn mreq4 = {
358 .imr_multiaddr = mdns_address_ipv4.in.sin_addr,
359 .imr_ifindex = index,
361 setsockopt(mesh->discovery.sockets[0].fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq4, sizeof(mreq4));
362 setsockopt(mesh->discovery.sockets[0].fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq4, sizeof(mreq4));
364 struct ipv6_mreq mreq6 = {
365 .ipv6mr_multiaddr = mdns_address_ipv6.in6.sin6_addr,
366 .ipv6mr_interface = index,
368 setsockopt(mesh->discovery.sockets[1].fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq6, sizeof(mreq6));
369 setsockopt(mesh->discovery.sockets[1].fd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &mreq6, sizeof(mreq6));
371 // Send an announcement for all addresses associated with this interface
372 for(int i = 0; i < mesh->discovery.address_count; i++) {
373 if(mesh->discovery.addresses[i].index == index) {
374 send_mdns_packet(mesh, &mesh->discovery.addresses[i]);
378 handle_network_change(mesh, true);
381 static void iface_down(meshlink_handle_t *mesh, int index) {
382 int *p = bsearch(&index, mesh->discovery.ifaces, mesh->discovery.iface_count, sizeof(*p), iface_compare);
388 // Drop multicast membership
389 struct ip_mreqn mreq4 = {
390 .imr_multiaddr = mdns_address_ipv4.in.sin_addr,
391 .imr_ifindex = index,
393 setsockopt(mesh->discovery.sockets[0].fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq4, sizeof(mreq4));
395 struct ipv6_mreq mreq6 = {
396 .ipv6mr_multiaddr = mdns_address_ipv6.in6.sin6_addr,
397 .ipv6mr_interface = index,
399 setsockopt(mesh->discovery.sockets[1].fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq6, sizeof(mreq6));
401 memmove(p, p + 1, (mesh->discovery.ifaces + --mesh->discovery.iface_count - p) * sizeof(*p));
403 handle_network_change(mesh, mesh->discovery.iface_count);
406 static void addr_add(meshlink_handle_t *mesh, const discovery_address_t *addr) {
407 discovery_address_t *p = bsearch(addr, mesh->discovery.addresses, mesh->discovery.address_count, sizeof(*p), address_compare);
413 bool up = bsearch(&addr->index, mesh->discovery.ifaces, mesh->discovery.iface_count, sizeof(int), iface_compare);
415 mesh->discovery.addresses = xrealloc(mesh->discovery.addresses, ++mesh->discovery.address_count * sizeof(*p));
416 mesh->discovery.addresses[mesh->discovery.address_count - 1] = *addr;
417 mesh->discovery.addresses[mesh->discovery.address_count - 1].up = up;
420 send_mdns_packet(mesh, &mesh->discovery.addresses[mesh->discovery.address_count - 1]);
423 qsort(mesh->discovery.addresses, mesh->discovery.address_count, sizeof(*p), address_compare);
426 static void addr_del(meshlink_handle_t *mesh, const discovery_address_t *addr) {
427 discovery_address_t *p = bsearch(addr, mesh->discovery.addresses, mesh->discovery.address_count, sizeof(*p), address_compare);
433 memmove(p, p + 1, (mesh->discovery.addresses + --mesh->discovery.address_count - p) * sizeof(*p));
436 void scan_ifaddrs(meshlink_handle_t *mesh) {
437 #ifdef HAVE_GETIFADDRS
438 struct ifaddrs *ifa = NULL;
440 if(getifaddrs(&ifa) == -1) {
441 logger(mesh, MESHLINK_ERROR, "Could not get list of interface addresses: %s", strerror(errno));
445 // Check for interfaces being removed
446 for(int i = 0; i < mesh->discovery.iface_count;) {
449 for(struct ifaddrs *ifap = ifa; ifap; ifap = ifap->ifa_next) {
450 if(!ifap->ifa_name) {
454 int index = if_nametoindex(ifap->ifa_name);
456 if(mesh->discovery.ifaces[i] == index) {
463 iface_down(mesh, mesh->discovery.ifaces[i]);
469 // Check for addresses being removed
470 for(int i = 0; i < mesh->discovery.address_count;) {
471 discovery_address_t *p = &mesh->discovery.addresses[i];
474 for(struct ifaddrs *ifap = ifa; ifap; ifap = ifap->ifa_next) {
475 if(!ifap->ifa_name || !ifap->ifa_addr) {
479 int index = if_nametoindex(ifap->ifa_name);
481 if(p->index == index && sockaddrcmp_noport(&p->address, (sockaddr_t *)ifap->ifa_addr) == 0) {
489 memmove(p, p + 1, (mesh->discovery.addresses + --mesh->discovery.address_count - p) * sizeof(*p));
495 // Check for interfaces state changes and addresses going up
496 for(struct ifaddrs *ifap = ifa; ifap; ifap = ifap->ifa_next) {
497 if(!ifap->ifa_name) {
501 int index = if_nametoindex(ifap->ifa_name);
503 if(ifap->ifa_flags & IFF_UP && ifap->ifa_flags & IFF_MULTICAST && !(ifap->ifa_flags & IFF_LOOPBACK)) {
504 iface_up(mesh, index);
506 iface_down(mesh, index);
509 if(!ifap->ifa_addr) {
513 discovery_address_t addr = {
517 sockaddr_t *sa = (sockaddr_t *)ifap->ifa_addr;
519 if(sa->sa.sa_family == AF_INET) {
520 memcpy(&addr.address.in, &sa->in, sizeof(sa->in));
521 addr.address.in.sin_port = ntohs(5353);
522 } else if(sa->sa.sa_family == AF_INET6) {
523 memcpy(&addr.address.in6, &sa->in6, sizeof(sa->in6));
524 addr.address.in6.sin6_port = ntohs(5353);
526 addr.address.sa.sa_family = AF_UNKNOWN;
529 if(addr.address.sa.sa_family != AF_UNKNOWN) {
530 addr_add(mesh, &addr);
541 static void netlink_getlink(int fd) {
542 static const struct {
544 struct ifinfomsg ifi;
546 .nlm.nlmsg_len = NLMSG_LENGTH(sizeof(msg.ifi)),
547 .nlm.nlmsg_type = RTM_GETLINK,
548 .nlm.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
550 .ifi.ifi_family = AF_UNSPEC,
552 send(fd, &msg, msg.nlm.nlmsg_len, 0);
555 static void netlink_getaddr(int fd) {
556 static const struct {
558 struct ifaddrmsg ifa;
560 .nlm.nlmsg_len = NLMSG_LENGTH(sizeof(msg.ifa)),
561 .nlm.nlmsg_type = RTM_GETADDR,
562 .nlm.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
564 .ifa.ifa_family = AF_UNSPEC,
566 send(fd, &msg, msg.nlm.nlmsg_len, 0);
569 static void netlink_parse_link(meshlink_handle_t *mesh, const struct nlmsghdr *nlm) {
570 const struct ifinfomsg *ifi = (const struct ifinfomsg *)(nlm + 1);
572 if(ifi->ifi_flags & IFF_UP && ifi->ifi_flags & IFF_MULTICAST) {
573 iface_up(mesh, ifi->ifi_index);
575 iface_down(mesh, ifi->ifi_index);
579 static void netlink_parse_addr(meshlink_handle_t *mesh, const struct nlmsghdr *nlm) {
580 const struct ifaddrmsg *ifa = (const struct ifaddrmsg *)(nlm + 1);
581 const uint8_t *ptr = (const uint8_t *)(ifa + 1);
582 size_t len = nlm->nlmsg_len - (ptr - (const uint8_t *)nlm);
584 while(len >= sizeof(struct rtattr)) {
585 const struct rtattr *rta = (const struct rtattr *)ptr;
587 if(rta->rta_len <= 0 || rta->rta_len > len) {
591 if(rta->rta_type == IFA_ADDRESS) {
592 discovery_address_t addr = {
593 .index = ifa->ifa_index,
596 if(rta->rta_len == 8) {
597 addr.address.sa.sa_family = AF_INET;
598 memcpy(&addr.address.in.sin_addr, ptr + 4, 4);
599 addr.address.in.sin_port = ntohs(5353);
600 } else if(rta->rta_len == 20) {
601 addr.address.sa.sa_family = AF_INET6;
602 memcpy(&addr.address.in6.sin6_addr, ptr + 4, 16);
603 addr.address.in6.sin6_port = ntohs(5353);
604 addr.address.in6.sin6_scope_id = ifa->ifa_index;
606 addr.address.sa.sa_family = AF_UNKNOWN;
609 if(addr.address.sa.sa_family != AF_UNKNOWN) {
610 if(nlm->nlmsg_type == RTM_NEWADDR) {
611 addr_add(mesh, &addr);
613 addr_del(mesh, &addr);
618 unsigned short rta_len = (rta->rta_len + 3) & ~3;
624 static void netlink_parse(meshlink_handle_t *mesh, const void *data, size_t len) {
625 const uint8_t *ptr = data;
627 while(len >= sizeof(struct nlmsghdr)) {
628 const struct nlmsghdr *nlm = (const struct nlmsghdr *)ptr;
630 if(nlm->nlmsg_len > len) {
634 switch(nlm->nlmsg_type) {
637 netlink_parse_link(mesh, nlm);
642 netlink_parse_addr(mesh, nlm);
645 ptr += nlm->nlmsg_len;
646 len -= nlm->nlmsg_len;
650 static void netlink_io_handler(event_loop_t *loop, void *data, int flags) {
653 meshlink_handle_t *mesh = loop->data;
661 ssize_t result = recv(mesh->discovery.pfroute_io.fd, &msg, sizeof(msg), MSG_DONTWAIT);
664 if(result == 0 || errno == EAGAIN || errno == EINTR) {
668 logger(mesh, MESHLINK_ERROR, "Reading from Netlink socket failed: %s\n", strerror(errno));
669 io_set(loop, &mesh->discovery.pfroute_io, 0);
672 if((size_t)result < sizeof(msg.nlm)) {
673 logger(mesh, MESHLINK_ERROR, "Invalid Netlink message\n");
677 if(msg.nlm.nlmsg_type == NLMSG_DONE) {
678 if(msg.nlm.nlmsg_seq == 1) {
679 // We just got the result of GETLINK, now send GETADDR.
680 netlink_getaddr(mesh->discovery.pfroute_io.fd);
683 netlink_parse(mesh, &msg, result);
685 if(loop->now.tv_sec > mesh->discovery.last_update + 5) {
686 mesh->discovery.last_update = loop->now.tv_sec;
687 handle_network_change(mesh, true);
692 #elif defined(__APPLE__)
693 static void reachability_change_callback(SCNetworkReachabilityRef reachability, SCNetworkReachabilityFlags flags, void *info) {
697 meshlink_handle_t *mesh = info;
699 pthread_mutex_lock(&mesh->mutex);
703 if(mesh->loop.now.tv_sec > mesh->discovery.last_update + 5) {
704 logger(mesh, MESHLINK_INFO, "Network change detected");
705 mesh->discovery.last_update = mesh->loop.now.tv_sec;
706 handle_network_change(mesh, true);
709 pthread_mutex_unlock(&mesh->mutex);
712 static void *network_change_handler(void *arg) {
713 meshlink_handle_t *mesh = arg;
715 mesh->discovery.runloop = CFRunLoopGetCurrent();
717 SCNetworkReachabilityRef reach_v4 = SCNetworkReachabilityCreateWithName(NULL, "93.184.216.34");
718 SCNetworkReachabilityRef reach_v6 = SCNetworkReachabilityCreateWithName(NULL, "2606:2800:220:1:248:1893:25c8:1946");
720 SCNetworkReachabilityContext context;
721 memset(&context, 0, sizeof(context));
725 SCNetworkReachabilitySetCallback(reach_v4, reachability_change_callback, &context);
726 SCNetworkReachabilityScheduleWithRunLoop(reach_v4, mesh->discovery.runloop, kCFRunLoopDefaultMode);
728 logger(mesh, MESHLINK_ERROR, "Could not create IPv4 network reachability watcher");
732 SCNetworkReachabilitySetCallback(reach_v6, reachability_change_callback, &context);
733 SCNetworkReachabilityScheduleWithRunLoop(reach_v6, mesh->discovery.runloop, kCFRunLoopDefaultMode);
735 logger(mesh, MESHLINK_ERROR, "Could not create IPv6 network reachability watcher");
740 mesh->discovery.runloop = NULL;
743 SCNetworkReachabilityUnscheduleFromRunLoop(reach_v4, mesh->discovery.runloop, kCFRunLoopDefaultMode);
748 SCNetworkReachabilityUnscheduleFromRunLoop(reach_v6, mesh->discovery.runloop, kCFRunLoopDefaultMode);
754 #elif defined(RTM_NEWADDR)
755 static void pfroute_parse_iface(meshlink_handle_t *mesh, const struct rt_msghdr *rtm) {
756 const struct if_msghdr *ifm = (const struct if_msghdr *)rtm;
758 if(ifm->ifm_flags & IFF_UP && ifm->ifm_flags & IFF_MULTICAST && !(ifm->ifm_flags & IFF_LOOPBACK)) {
759 iface_up(mesh, ifm->ifm_index);
761 iface_down(mesh, ifm->ifm_index);
765 static void pfroute_parse_addr(meshlink_handle_t *mesh, const struct rt_msghdr *rtm) {
766 const struct ifa_msghdr *ifam = (const struct ifa_msghdr *)rtm;
767 const char *p = (const char *)(ifam + 1);
769 for(unsigned int i = 1; i; i <<= 1) {
770 if(!(ifam->ifam_addrs & i)) {
774 const sockaddr_t *sa = (const sockaddr_t *)p;
777 discovery_address_t addr = {
778 .index = ifam->ifam_index,
781 if(sa->sa.sa_family == AF_INET) {
782 addr.address.in = sa->in;
783 addr.address.in.sin_port = ntohs(5353);
784 } else if(sa->sa.sa_family == AF_INET6) {
785 addr.address.in6 = sa->in6;
786 addr.address.in6.sin6_port = ntohs(5353);
788 addr.address.sa.sa_family = AF_UNKNOWN;
791 if(addr.address.sa.sa_family != AF_UNKNOWN) {
792 if(ifam->ifam_type == RTM_NEWADDR) {
793 addr_add(mesh, &addr);
795 addr_del(mesh, &addr);
802 size_t len = (sa->sa.sa_len + 3) & ~3;
807 static void pfroute_io_handler(event_loop_t *loop, void *data, int flags) {
810 meshlink_handle_t *mesh = loop->data;
813 struct rt_msghdr rtm;
818 msg.rtm.rtm_version = 0;
819 ssize_t result = recv(mesh->discovery.pfroute_io.fd, &msg, sizeof(msg), MSG_DONTWAIT);
822 if(result == 0 || errno == EAGAIN || errno == EINTR) {
826 logger(mesh, MESHLINK_ERROR, "Reading from PFROUTE socket failed: %s\n", strerror(errno));
827 io_set(loop, &mesh->discovery.pfroute_io, 0);
830 if(msg.rtm.rtm_version != RTM_VERSION) {
831 logger(mesh, MESHLINK_ERROR, "Invalid PFROUTE message version\n");
835 switch(msg.rtm.rtm_type) {
837 pfroute_parse_iface(mesh, &msg.rtm);
842 pfroute_parse_addr(mesh, &msg.rtm);
852 bool discovery_start(meshlink_handle_t *mesh) {
853 logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
857 // Set up multicast sockets for mDNS
858 static const int one = 1;
859 static const int ttl = 255;
860 static const uint8_t one8 = 1;
861 static const uint8_t ttl8 = 255;
863 int fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
866 logger(mesh, MESHLINK_ERROR, "Error creating IPv4 socket: %s", strerror(errno));
870 .in.sin_family = AF_INET,
871 .in.sin_port = ntohs(5353),
873 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
875 setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one));
877 setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one8, sizeof(one8));
878 setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl8, sizeof(ttl8));
880 if(bind(fd, &sa4.sa, SALEN(sa4.sa)) == -1) {
881 logger(mesh, MESHLINK_ERROR, "Error binding to IPv4 multicast socket: %s", strerror(errno));
883 io_add(&mesh->loop, &mesh->discovery.sockets[0], mdns_io_handler, &mesh->discovery.sockets[0], fd, IO_READ);
887 .in6.sin6_family = AF_INET6,
888 .in6.sin6_port = ntohs(5353),
890 fd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
893 logger(mesh, MESHLINK_ERROR, "Error creating IPv6 socket: %s", strerror(errno));
896 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
898 setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one));
900 setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
901 setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one));
902 setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl));
903 setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl));
905 if(bind(fd, &sa6.sa, SALEN(sa6.sa)) == -1) {
906 logger(mesh, MESHLINK_ERROR, "Error binding to IPv4 multicast socket: %s", strerror(errno));
908 io_add(&mesh->loop, &mesh->discovery.sockets[1], mdns_io_handler, &mesh->discovery.sockets[1], fd, IO_READ);
912 int sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
915 struct sockaddr_nl sa;
916 memset(&sa, 0, sizeof(sa));
917 sa.nl_family = AF_NETLINK;
918 sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_IFADDR;
920 if(bind(sock, (struct sockaddr *)&sa, sizeof(sa)) != -1) {
921 io_add(&mesh->loop, &mesh->discovery.pfroute_io, netlink_io_handler, NULL, sock, IO_READ);
922 netlink_getlink(sock);
924 logger(mesh, MESHLINK_WARNING, "Could not bind AF_NETLINK socket: %s", strerror(errno));
928 logger(mesh, MESHLINK_WARNING, "Could not open AF_NETLINK socket: %s", strerror(errno));
932 #elif defined(__APPLE__)
933 pthread_create(&mesh->discovery.thread, NULL, network_change_handler, mesh);
934 // TODO: Do we need to wait for the thread to start succesfully?
936 #elif defined(RTM_NEWADDR)
937 int sock = socket(PF_ROUTE, SOCK_RAW, AF_UNSPEC);
940 io_add(&mesh->loop, &mesh->discovery.pfroute_io, pfroute_io_handler, NULL, sock, IO_READ);
942 logger(mesh, MESHLINK_WARNING, "Could not open PF_ROUTE socket: %s", strerror(errno));
951 void discovery_stop(meshlink_handle_t *mesh) {
952 logger(mesh, MESHLINK_DEBUG, "discovery_stop called\n");
956 free(mesh->discovery.ifaces);
957 free(mesh->discovery.addresses);
958 mesh->discovery.ifaces = NULL;
959 mesh->discovery.addresses = NULL;
960 mesh->discovery.iface_count = 0;
961 mesh->discovery.address_count = 0;
963 #if defined(__APPLE__)
965 if(mesh->discovery.runloop) {
966 CFRunLoopStop(mesh->discovery.runloop);
967 pthread_join(mesh->discovery.thread, NULL);
972 if(mesh->discovery.pfroute_io.cb) {
973 close(mesh->discovery.pfroute_io.fd);
974 io_del(&mesh->loop, &mesh->discovery.pfroute_io);
977 for(int i = 0; i < 2; i++) {
978 if(mesh->discovery.sockets[i].cb) {
979 close(mesh->discovery.sockets[i].fd);
980 io_del(&mesh->loop, &mesh->discovery.sockets[i]);
985 void discovery_refresh(meshlink_handle_t *mesh) {
986 for(int i = 0; i < mesh->discovery.address_count; i++) {
987 if(mesh->discovery.addresses[i].up) {
988 send_mdns_packet(mesh, &mesh->discovery.addresses[i]);