]> git.meshlink.io Git - meshlink/commitdiff
Add local discovery support for macOS.
authorGuus Sliepen <guus@meshlink.io>
Thu, 13 Aug 2020 20:48:06 +0000 (22:48 +0200)
committerGuus Sliepen <guus@meshlink.io>
Tue, 26 Jan 2021 20:43:45 +0000 (21:43 +0100)
This implements the pfroute counterpart to Linux's netlink interface.
Pfroute doesn't allow easy querying the current interfaces and addresses,
so we use getifaddrs() for that.

src/discovery.c

index 6fec9a2466299592fb51b6f6cf47e145723416b5..eb29c735f63e4c3e06a3c9f840243fd10b5183d0 100644 (file)
@@ -1,7 +1,10 @@
+#define __APPLE_USE_RFC_3542
 #include "system.h"
 
 #if defined(__APPLE__) || defined(__unix) && !defined(__linux)
+#include <net/if.h>
 #include <net/route.h>
+#include <netinet/in.h>
 #elif defined(__linux)
 #include <asm/types.h>
 #include <net/if.h>
 #define MESHLINK_MDNS_NAME_KEY "name"
 #define MESHLINK_MDNS_FINGERPRINT_KEY "fingerprint"
 
+#ifndef MSG_NOSIGNAL
+#define MSG_NOSIGNAL 0
+#endif
+
+#ifndef IPV6_ADD_MEMBERSHIP
+#define IPV6_ADD_MEMBERSHIP IPV6_JOIN_GROUP
+#endif
+
+#ifndef IPV6_DROP_MEMBERSHIP
+#define IPV6_DROP_MEMBERSHIP IPV6_LEAVE_GROUP
+#endif
+
 static const sockaddr_t mdns_address_ipv4 = {
        .in.sin_family = AF_INET,
        .in.sin_addr.s_addr = 0xfb0000e0,
@@ -99,6 +114,9 @@ static void send_mdns_packet_ipv4(meshlink_handle_t *mesh, int fd, int index, co
        // Send the packet
        ssize_t result = sendmsg(fd, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
 #else
+       (void)index;
+       (void)src;
+
        // Send the packet
        ssize_t result = sendto(fd, data, len, MSG_DONTWAIT | MSG_NOSIGNAL, &dest->sa, SALEN(dest->sa));
 #endif
@@ -145,6 +163,9 @@ static void send_mdns_packet_ipv6(meshlink_handle_t *mesh, int fd, int index, co
        // Send the packet
        ssize_t result = sendmsg(fd, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
 #else
+       (void)index;
+       (void)src;
+
        // Send the packet
        ssize_t result = sendto(fd, data, len, MSG_DONTWAIT | MSG_NOSIGNAL, &dest->sa, SALEN(dest->sa));
 #endif
@@ -444,11 +465,11 @@ static void netlink_parse_addr(meshlink_handle_t *mesh, const struct nlmsghdr *n
                        if(rta->rta_len == 8) {
                                addr.address.sa.sa_family = AF_INET;
                                memcpy(&addr.address.in.sin_addr, ptr + 4, 4);
-                               addr.address.in.sin_port = 5353;
+                               addr.address.in.sin_port = ntohs(5353);
                        } else if(rta->rta_len == 20) {
                                addr.address.sa.sa_family = AF_INET6;
                                memcpy(&addr.address.in6.sin6_addr, ptr + 4, 16);
-                               addr.address.in6.sin6_port = 5353;
+                               addr.address.in6.sin6_port = ntohs(5353);
                                addr.address.in6.sin6_scope_id = ifa->ifa_index;
                        } else {
                                addr.address.sa.sa_family = AF_UNKNOWN;
@@ -539,10 +560,61 @@ static void netlink_io_handler(event_loop_t *loop, void *data, int flags) {
        }
 }
 #elif defined(RTM_NEWADDR)
+static void pfroute_parse_iface(meshlink_handle_t *mesh, const struct rt_msghdr *rtm) {
+       const struct if_msghdr *ifm = (const struct if_msghdr *)rtm;
+
+       if(ifm->ifm_flags & IFF_UP && ifm->ifm_flags & IFF_MULTICAST && !(ifm->ifm_flags & IFF_LOOPBACK)) {
+               iface_up(mesh, ifm->ifm_index);
+       } else {
+               iface_down(mesh, ifm->ifm_index);
+       }
+}
+
+static void pfroute_parse_addr(meshlink_handle_t *mesh, const struct rt_msghdr *rtm) {
+       const struct ifa_msghdr *ifam = (const struct ifa_msghdr *)rtm;
+       const char *p = (const char *)(ifam + 1);
+
+       for(unsigned int i = 1; i; i <<= 1) {
+               if(!(ifam->ifam_addrs & i)) {
+                       continue;
+               }
+
+               const sockaddr_t *sa = (const sockaddr_t *)p;
+
+               if(i == RTA_IFA) {
+                       discovery_address_t addr = {
+                               .index = ifam->ifam_index,
+                       };
+
+                       if(sa->sa.sa_family == AF_INET) {
+                               addr.address.in = sa->in;
+                               addr.address.in.sin_port = ntohs(5353);
+                       } else if(sa->sa.sa_family == AF_INET6) {
+                               addr.address.in6 = sa->in6;
+                               addr.address.in6.sin6_port = ntohs(5353);
+                       } else {
+                               addr.address.sa.sa_family = AF_UNKNOWN;
+                       }
+
+                       if(addr.address.sa.sa_family != AF_UNKNOWN) {
+                               if(ifam->ifam_type == RTM_NEWADDR) {
+                                       addr_add(mesh, &addr);
+                               } else {
+                                       addr_del(mesh, &addr);
+                               }
+                       }
+
+                       break;
+               }
+
+               size_t len = (sa->sa.sa_len + 3) & ~3;
+               p += len;
+       }
+}
+
 static void pfroute_io_handler(event_loop_t *loop, void *data, int flags) {
        (void)flags;
        (void)data;
-       static time_t prev_update;
        meshlink_handle_t *mesh = loop->data;
 
        struct {
@@ -570,13 +642,12 @@ static void pfroute_io_handler(event_loop_t *loop, void *data, int flags) {
 
                switch(msg.rtm.rtm_type) {
                case RTM_IFINFO:
+                       pfroute_parse_iface(mesh, &msg.rtm);
+                       break;
+
                case RTM_NEWADDR:
                case RTM_DELADDR:
-                       if(loop->now.tv_sec > prev_update + 5) {
-                               prev_update = loop->now.tv_sec;
-                               handle_network_change(mesh, 1);
-                       }
-
+                       pfroute_parse_addr(mesh, &msg.rtm);
                        break;
 
                default:
@@ -594,6 +665,8 @@ bool discovery_start(meshlink_handle_t *mesh) {
        // Set up multicast sockets for mDNS
        static const int one = 1;
        static const int ttl = 255;
+       static const uint8_t one8 = 1;
+       static const uint8_t ttl8 = 255;
 
        int fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
        sockaddr_t sa4 = {
@@ -601,9 +674,9 @@ bool discovery_start(meshlink_handle_t *mesh) {
                .in.sin_port = ntohs(5353),
        };
        setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+       setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one8, sizeof(one8));
+       setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl8, sizeof(ttl8));
        bind(fd, &sa4.sa, SALEN(sa4.sa));
-       setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one));
-       setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
        io_add(&mesh->loop, &mesh->discovery.sockets[0], mdns_io_handler, &mesh->discovery.sockets[0], fd, IO_READ);
 
        sockaddr_t sa6 = {
@@ -613,9 +686,10 @@ bool discovery_start(meshlink_handle_t *mesh) {
        fd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
        setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
        setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
-       bind(fd, &sa6.sa, SALEN(sa6.sa));
        setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one));
        setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl));
+       setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl));
+       bind(fd, &sa6.sa, SALEN(sa6.sa));
        io_add(&mesh->loop, &mesh->discovery.sockets[1], mdns_io_handler, &mesh->discovery.sockets[1], fd, IO_READ);
 
 #if defined(__linux)
@@ -646,6 +720,51 @@ bool discovery_start(meshlink_handle_t *mesh) {
                logger(mesh, MESHLINK_WARNING, "Could not open PF_ROUTE socket: %s", strerror(errno));
        }
 
+       struct ifaddrs *ifa = NULL;
+
+       if(getifaddrs(&ifa) == -1) {
+               logger(mesh, MESHLINK_ERROR, "Could not get list of interface addresses: %s", strerror(errno));
+               return true;
+       }
+
+       for(struct ifaddrs *ifap = ifa; ifap; ifap = ifap->ifa_next) {
+               if(!ifap->ifa_name) {
+                       continue;
+               }
+
+               int index = if_nametoindex(ifap->ifa_name);
+
+               if(ifap->ifa_flags & IFF_UP && ifap->ifa_flags & IFF_MULTICAST && !(ifap->ifa_flags & IFF_LOOPBACK)) {
+                       iface_up(mesh, index);
+               }
+
+               if(!ifap->ifa_addr) {
+                       continue;
+               }
+
+               discovery_address_t addr  = {
+                       .index = index,
+               };
+
+               sockaddr_t *sa = (sockaddr_t *)ifap->ifa_addr;
+
+               if(sa->sa.sa_family == AF_INET) {
+                       memcpy(&addr.address.in, &sa->in, sizeof(sa->in));
+                       addr.address.in.sin_port = ntohs(5353);
+               } else if(sa->sa.sa_family == AF_INET6) {
+                       memcpy(&addr.address.in6, &sa->in6, sizeof(sa->in6));
+                       addr.address.in6.sin6_port = ntohs(5353);
+               } else {
+                       addr.address.sa.sa_family = AF_UNKNOWN;
+               }
+
+               if(addr.address.sa.sa_family != AF_UNKNOWN) {
+                       addr_add(mesh, &addr);
+               }
+       }
+
+       freeifaddrs(ifa);
+
 #endif
 
        return true;