3 #if defined(__APPLE__) || defined(__unix) && !defined(__linux)
8 #include <linux/if_link.h>
9 #include <linux/netlink.h>
10 #include <linux/rtnetlink.h>
14 #include "meshlink_internal.h"
16 #include "discovery.h"
21 #include "connection.h"
25 #define MESHLINK_MDNS_SERVICE_TYPE "_%s._tcp"
26 #define MESHLINK_MDNS_NAME_KEY "name"
27 #define MESHLINK_MDNS_FINGERPRINT_KEY "fingerprint"
29 static const sockaddr_t mdns_address_ipv4 = {
30 .in.sin_family = AF_INET,
31 .in.sin_addr.s_addr = 0xfb0000e0,
32 .in.sin_port = 0xe914,
35 static const sockaddr_t mdns_address_ipv6 = {
36 .in6.sin6_family = AF_INET6,
37 .in6.sin6_addr.s6_addr[0x0] = 0xfd,
38 .in6.sin6_addr.s6_addr[0x1] = 0x02,
39 .in6.sin6_addr.s6_addr[0xf] = 0xfb,
40 .in6.sin6_port = 0xe914,
43 typedef struct discovery_address {
47 } discovery_address_t;
49 static int iface_compare(const void *va, const void *vb) {
55 static int address_compare(const void *va, const void *vb) {
56 const discovery_address_t *a = va;
57 const discovery_address_t *b = vb;
59 if(a->index != b->index) {
60 return a->index - b->index;
63 return sockaddrcmp_noport(&a->address, &b->address);
66 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) {
73 struct in_pktinfo pkti = {
75 .ipi_addr = src->in.sin_addr,
79 char buf[CMSG_SPACE(sizeof(pkti))];
84 .msg_name = (struct sockaddr *) &dest->sa,
85 .msg_namelen = SALEN(dest->sa),
89 .msg_controllen = sizeof(u.buf),
93 struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
94 cmsg->cmsg_level = IPPROTO_IP;
95 cmsg->cmsg_type = IP_PKTINFO;
96 cmsg->cmsg_len = CMSG_LEN(sizeof(pkti));
97 memcpy(CMSG_DATA(cmsg), &pkti, sizeof(pkti));
100 ssize_t result = sendmsg(fd, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
103 ssize_t result = sendto(fd, data, len, MSG_DONTWAIT | MSG_NOSIGNAL, &dest->sa, SALEN(dest->sa));
107 logger(mesh, MESHLINK_ERROR, "Error sending multicast packet: %s", strerror(errno));
111 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) {
118 struct in6_pktinfo pkti = {
119 .ipi6_ifindex = index,
120 .ipi6_addr = src->in6.sin6_addr,
124 char buf[CMSG_SPACE(sizeof(pkti))];
125 struct cmsghdr align;
128 memset(&u, 0, sizeof u);
130 struct msghdr msg = {
131 .msg_name = (struct sockaddr *) &dest->sa,
132 .msg_namelen = SALEN(dest->sa),
135 .msg_control = u.buf,
136 .msg_controllen = CMSG_LEN(sizeof(pkti)),
139 struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
140 cmsg->cmsg_level = IPPROTO_IPV6;
141 cmsg->cmsg_type = IPV6_PKTINFO;
142 cmsg->cmsg_len = CMSG_LEN(sizeof(pkti));
143 memcpy(CMSG_DATA(cmsg), &pkti, sizeof(pkti));
146 ssize_t result = sendmsg(fd, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
149 ssize_t result = sendto(fd, data, len, MSG_DONTWAIT | MSG_NOSIGNAL, &dest->sa, SALEN(dest->sa));
153 logger(mesh, MESHLINK_ERROR, "Error sending multicast packet: %s", strerror(errno));
157 static void send_mdns_packet(meshlink_handle_t *mesh, const discovery_address_t *addr) {
158 // Configure the socket to send the packet to the right interface
161 char *fingerprint = meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self);
162 const char *keys[] = {MESHLINK_MDNS_NAME_KEY, MESHLINK_MDNS_FINGERPRINT_KEY};
163 const char *values[] = {mesh->name, fingerprint};
164 size_t size = prepare_packet(data, sizeof data, fingerprint, mesh->appname, "tcp", atoi(mesh->myport), 2, keys, values, false);
167 switch(addr->address.sa.sa_family) {
169 fd = mesh->discovery.sockets[0].fd;
170 #ifdef IP_MULTICAST_IF
172 struct ip_mreqn mreq = {
173 .imr_address = addr->address.in.sin_addr,
174 .imr_ifindex = addr->index,
177 if(setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF, &mreq, sizeof(mreq)) != 0) {
178 logger(mesh, MESHLINK_ERROR, "Could not set outgoing multicast interface on IPv4 socket");
185 send_mdns_packet_ipv4(mesh, fd, addr->index, &addr->address, &mdns_address_ipv4, data, size);
189 fd = mesh->discovery.sockets[1].fd;
190 #ifdef IPV6_MULTICAST_IF
192 if(setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &addr->index, sizeof(addr->index)) != 0) {
193 logger(mesh, MESHLINK_ERROR, "Could not set outgoing multicast interface on IPv6 socket");
199 send_mdns_packet_ipv6(mesh, fd, addr->index, &addr->address, &mdns_address_ipv6, data, size);
207 static void mdns_io_handler(event_loop_t *loop, void *data, int flags) {
209 meshlink_handle_t *mesh = loop->data;
213 socklen_t sl = sizeof(sa);
215 ssize_t len = recvfrom(io->fd, buf, sizeof(buf), MSG_DONTWAIT, &sa.sa, &sl);
218 if(!sockwouldblock(errno)) {
219 logger(mesh, MESHLINK_ERROR, "Error reading from mDNS discovery socket: %s", strerror(errno));
228 const char *keys[2] = {MESHLINK_MDNS_NAME_KEY, MESHLINK_MDNS_FINGERPRINT_KEY};
229 char *values[2] = {NULL, NULL};
232 if(parse_packet(buf, len, &name, mesh->appname, "tcp", &port, 2, keys, values, &response)) {
233 node_t *n = (node_t *)meshlink_get_node(mesh, values[0]);
236 if(n != mesh->self) {
237 logger(mesh, MESHLINK_INFO, "Node %s discovered on the local network.\n", n->name);
240 if(!response && n != mesh->self) {
241 // Send a unicast response back
242 char *fingerprint = meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self);
243 const char *response_values[] = {mesh->name, fingerprint};
244 size_t size = prepare_packet(buf, sizeof(buf), fingerprint, mesh->appname, "tcp", atoi(mesh->myport), 2, keys, response_values, true);
245 sendto(io->fd, buf, size, MSG_DONTWAIT | MSG_NOSIGNAL, &sa.sa, sl);
249 switch(sa.sa.sa_family) {
251 sa.in.sin_port = port;
255 sa.in6.sin6_port = port;
259 logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", n->name);
260 sa.sa.sa_family = AF_UNKNOWN;
264 if(sa.sa.sa_family != AF_UNKNOWN) {
265 n->catta_address = sa;
266 node_add_recent_address(mesh, n, &sa);
268 connection_t *c = n->connection;
270 if(c && c->outgoing && !c->status.active) {
271 c->outgoing->timeout = 0;
273 if(c->outgoing->ev.cb) {
274 timeout_set(&mesh->loop, &c->outgoing->ev, &(struct timespec) {
279 c->last_ping_time = -3600;
287 for(int i = 0; i < 2; i++) {
292 static void iface_up(meshlink_handle_t *mesh, int index) {
293 int *p = bsearch(&index, mesh->discovery.ifaces, mesh->discovery.iface_count, sizeof(*p), iface_compare);
299 mesh->discovery.ifaces = xrealloc(mesh->discovery.ifaces, ++mesh->discovery.iface_count * sizeof(*p));
300 mesh->discovery.ifaces[mesh->discovery.iface_count - 1] = index;
301 qsort(mesh->discovery.ifaces, mesh->discovery.iface_count, sizeof(*p), iface_compare);
303 // Add multicast membership
304 struct ip_mreqn mreq4 = {
305 .imr_multiaddr = mdns_address_ipv4.in.sin_addr,
306 .imr_ifindex = index,
308 setsockopt(mesh->discovery.sockets[0].fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq4, sizeof(mreq4));
309 setsockopt(mesh->discovery.sockets[0].fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq4, sizeof(mreq4));
311 struct ipv6_mreq mreq6 = {
312 .ipv6mr_multiaddr = mdns_address_ipv6.in6.sin6_addr,
313 .ipv6mr_interface = index,
315 setsockopt(mesh->discovery.sockets[1].fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq6, sizeof(mreq6));
316 setsockopt(mesh->discovery.sockets[1].fd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &mreq6, sizeof(mreq6));
318 // Send an announcement for all addresses associated with this interface
319 for(int i = 0; i < mesh->discovery.address_count; i++) {
320 if(mesh->discovery.addresses[i].index == index) {
321 send_mdns_packet(mesh, &mesh->discovery.addresses[i]);
325 handle_network_change(mesh, true);
328 static void iface_down(meshlink_handle_t *const mesh, int index) {
329 int *p = bsearch(&index, mesh->discovery.ifaces, mesh->discovery.iface_count, sizeof(*p), iface_compare);
335 // Drop multicast membership
336 struct ip_mreqn mreq4 = {
337 .imr_multiaddr = mdns_address_ipv4.in.sin_addr,
338 .imr_ifindex = index,
340 setsockopt(mesh->discovery.sockets[0].fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq4, sizeof(mreq4));
342 struct ipv6_mreq mreq6 = {
343 .ipv6mr_multiaddr = mdns_address_ipv6.in6.sin6_addr,
344 .ipv6mr_interface = index,
346 setsockopt(mesh->discovery.sockets[1].fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq6, sizeof(mreq6));
348 memmove(p, p + 1, (mesh->discovery.ifaces + --mesh->discovery.iface_count - p) * sizeof(*p));
350 handle_network_change(mesh, mesh->discovery.iface_count);
353 static void addr_add(meshlink_handle_t *mesh, const discovery_address_t *addr) {
354 discovery_address_t *p = bsearch(addr, mesh->discovery.addresses, mesh->discovery.address_count, sizeof(*p), address_compare);
360 bool up = bsearch(&addr->index, mesh->discovery.ifaces, mesh->discovery.iface_count, sizeof(int), iface_compare);
362 mesh->discovery.addresses = xrealloc(mesh->discovery.addresses, ++mesh->discovery.address_count * sizeof(*p));
363 mesh->discovery.addresses[mesh->discovery.address_count - 1] = *addr;
364 mesh->discovery.addresses[mesh->discovery.address_count - 1].up = up;
367 send_mdns_packet(mesh, &mesh->discovery.addresses[mesh->discovery.address_count - 1]);
370 qsort(mesh->discovery.addresses, mesh->discovery.address_count, sizeof(*p), address_compare);
373 static void addr_del(meshlink_handle_t *mesh, const discovery_address_t *addr) {
374 discovery_address_t *p = bsearch(addr, mesh->discovery.addresses, mesh->discovery.address_count, sizeof(*p), address_compare);
380 memmove(p, p + 1, (mesh->discovery.addresses + --mesh->discovery.address_count - p) * sizeof(*p));
384 static void netlink_getlink(int fd) {
385 static const struct {
387 struct ifinfomsg ifi;
389 .nlm.nlmsg_len = NLMSG_LENGTH(sizeof(msg.ifi)),
390 .nlm.nlmsg_type = RTM_GETLINK,
391 .nlm.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
393 .ifi.ifi_family = AF_UNSPEC,
395 send(fd, &msg, msg.nlm.nlmsg_len, 0);
398 static void netlink_getaddr(int fd) {
399 static const struct {
401 struct ifaddrmsg ifa;
403 .nlm.nlmsg_len = NLMSG_LENGTH(sizeof(msg.ifa)),
404 .nlm.nlmsg_type = RTM_GETADDR,
405 .nlm.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
407 .ifa.ifa_family = AF_UNSPEC,
409 send(fd, &msg, msg.nlm.nlmsg_len, 0);
412 static void netlink_parse_link(meshlink_handle_t *mesh, const struct nlmsghdr *nlm) {
413 const struct ifinfomsg *ifi = (const struct ifinfomsg *)(nlm + 1);
415 if(ifi->ifi_flags & IFF_UP && ifi->ifi_flags & IFF_MULTICAST) {
416 iface_up(mesh, ifi->ifi_index);
418 iface_down(mesh, ifi->ifi_index);
422 static void netlink_parse_addr(meshlink_handle_t *mesh, const struct nlmsghdr *nlm) {
423 const struct ifaddrmsg *ifa = (const struct ifaddrmsg *)(nlm + 1);
424 const uint8_t *ptr = (const uint8_t *)(ifa + 1);
425 size_t len = nlm->nlmsg_len - (ptr - (const uint8_t *)nlm);
427 while(len >= sizeof(struct rtattr)) {
428 const struct rtattr *rta = (const struct rtattr *)ptr;
430 if(rta->rta_len <= 0 || rta->rta_len > len) {
434 if(rta->rta_type == IFA_ADDRESS) {
435 discovery_address_t addr = {
436 .index = ifa->ifa_index,
439 if(rta->rta_len == 8) {
440 addr.address.sa.sa_family = AF_INET;
441 memcpy(&addr.address.in.sin_addr, ptr + 4, 4);
442 addr.address.in.sin_port = 5353;
443 } else if(rta->rta_len == 20) {
444 addr.address.sa.sa_family = AF_INET6;
445 memcpy(&addr.address.in6.sin6_addr, ptr + 4, 16);
446 addr.address.in6.sin6_port = 5353;
447 addr.address.in6.sin6_scope_id = ifa->ifa_index;
449 addr.address.sa.sa_family = AF_UNKNOWN;
452 if(addr.address.sa.sa_family != AF_UNKNOWN) {
453 if(nlm->nlmsg_type == RTM_NEWADDR) {
454 addr_add(mesh, &addr);
456 addr_del(mesh, &addr);
461 unsigned short rta_len = (rta->rta_len + 3) & ~3;
467 static void netlink_parse(meshlink_handle_t *mesh, const void *data, size_t len) {
468 const uint8_t *ptr = data;
470 while(len >= sizeof(struct nlmsghdr)) {
471 const struct nlmsghdr *nlm = (const struct nlmsghdr *)ptr;
473 if(nlm->nlmsg_len > len) {
477 switch(nlm->nlmsg_type) {
480 netlink_parse_link(mesh, nlm);
485 netlink_parse_addr(mesh, nlm);
488 ptr += nlm->nlmsg_len;
489 len -= nlm->nlmsg_len;
493 static void netlink_io_handler(event_loop_t *loop, void *data, int flags) {
496 static time_t prev_update;
497 meshlink_handle_t *mesh = loop->data;
505 ssize_t result = recv(mesh->discovery.pfroute_io.fd, &msg, sizeof(msg), MSG_DONTWAIT);
508 if(result == 0 || errno == EAGAIN || errno == EINTR) {
512 logger(mesh, MESHLINK_ERROR, "Reading from Netlink socket failed: %s\n", strerror(errno));
513 io_set(loop, &mesh->discovery.pfroute_io, 0);
516 if((size_t)result < sizeof(msg.nlm)) {
517 logger(mesh, MESHLINK_ERROR, "Invalid Netlink message\n");
521 if(msg.nlm.nlmsg_type == NLMSG_DONE) {
522 if(msg.nlm.nlmsg_seq == 1) {
523 // We just got the result of GETLINK, now send GETADDR.
524 netlink_getaddr(mesh->discovery.pfroute_io.fd);
527 netlink_parse(mesh, &msg, result);
529 if(loop->now.tv_sec > prev_update + 5) {
530 prev_update = loop->now.tv_sec;
531 handle_network_change(mesh, 1);
536 #elif defined(RTM_NEWADDR)
537 static void pfroute_io_handler(event_loop_t *loop, void *data, int flags) {
540 static time_t prev_update;
541 meshlink_handle_t *mesh = loop->data;
544 struct rt_msghdr rtm;
549 msg.rtm.rtm_version = 0;
550 ssize_t result = recv(mesh->discovery.pfroute_io.fd, &msg, sizeof(msg), MSG_DONTWAIT);
553 if(result == 0 || errno == EAGAIN || errno == EINTR) {
557 logger(mesh, MESHLINK_ERROR, "Reading from PFROUTE socket failed: %s\n", strerror(errno));
558 io_set(loop, &mesh->discovery.pfroute_io, 0);
561 if(msg.rtm.rtm_version != RTM_VERSION) {
562 logger(mesh, MESHLINK_ERROR, "Invalid PFROUTE message version\n");
566 switch(msg.rtm.rtm_type) {
570 if(loop->now.tv_sec > prev_update + 5) {
571 prev_update = loop->now.tv_sec;
572 handle_network_change(mesh, 1);
584 bool discovery_start(meshlink_handle_t *mesh) {
585 logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
589 // Set up multicast sockets for mDNS
590 static const int one = 1;
591 static const int ttl = 255;
593 int fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
595 .in.sin_family = AF_INET,
596 .in.sin_port = ntohs(5353),
598 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
599 bind(fd, &sa4.sa, SALEN(sa4.sa));
600 setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one));
601 setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
602 io_add(&mesh->loop, &mesh->discovery.sockets[0], mdns_io_handler, &mesh->discovery.sockets[0], fd, IO_READ);
605 .in6.sin6_family = AF_INET6,
606 .in6.sin6_port = ntohs(5353),
608 fd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
609 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
610 setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
611 bind(fd, &sa6.sa, SALEN(sa6.sa));
612 setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one));
613 setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl));
614 io_add(&mesh->loop, &mesh->discovery.sockets[1], mdns_io_handler, &mesh->discovery.sockets[1], fd, IO_READ);
617 int sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
620 struct sockaddr_nl sa;
621 memset(&sa, 0, sizeof(sa));
622 sa.nl_family = AF_NETLINK;
623 sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_IFADDR;
625 if(bind(sock, (struct sockaddr *)&sa, sizeof(sa)) != -1) {
626 io_add(&mesh->loop, &mesh->discovery.pfroute_io, netlink_io_handler, NULL, sock, IO_READ);
627 netlink_getlink(sock);
629 logger(mesh, MESHLINK_WARNING, "Could not bind AF_NETLINK socket: %s", strerror(errno));
632 logger(mesh, MESHLINK_WARNING, "Could not open AF_NETLINK socket: %s", strerror(errno));
635 #elif defined(RTM_NEWADDR)
636 int sock = socket(PF_ROUTE, SOCK_RAW, AF_UNSPEC);
639 io_add(&mesh->loop, &mesh->discovery.pfroute_io, pfroute_io_handler, NULL, sock, IO_READ);
641 logger(mesh, MESHLINK_WARNING, "Could not open PF_ROUTE socket: %s", strerror(errno));
649 void discovery_stop(meshlink_handle_t *mesh) {
650 logger(mesh, MESHLINK_DEBUG, "discovery_stop called\n");
654 free(mesh->discovery.ifaces);
655 free(mesh->discovery.addresses);
656 mesh->discovery.ifaces = NULL;
657 mesh->discovery.addresses = NULL;
658 mesh->discovery.iface_count = 0;
659 mesh->discovery.address_count = 0;
661 if(mesh->discovery.pfroute_io.cb) {
662 close(mesh->discovery.pfroute_io.fd);
663 io_del(&mesh->loop, &mesh->discovery.pfroute_io);
666 for(int i = 0; i < 2; i++) {
667 if(mesh->discovery.sockets[i].cb) {
668 close(mesh->discovery.sockets[i].fd);
669 io_del(&mesh->loop, &mesh->discovery.sockets[i]);
674 void discovery_refresh(meshlink_handle_t *mesh) {
675 for(int i = 0; i < mesh->discovery.address_count; i++) {
676 if(mesh->discovery.addresses[i].up) {
677 send_mdns_packet(mesh, &mesh->discovery.addresses[i]);