Fix invitation URL generation when running in a network namespace.

MeshLink could call getifaddrs() in the namespace of the caller instead of
the MeshLink thread, causing the wrong addresses to be put in the inviation
URL.

diff --git a/src/meshlink.c b/src/meshlink.c
index d54fe30b1ae8f49500214036709f983b6a015ba3..340b6041cfee81d7f7ef641ec55794dae6c1e5f0 100644 (file)
--- a/src/meshlink.c
+++ b/src/meshlink.c
@@ -344,6 +344,52 @@ static bool is_localaddr(sockaddr_t *sa) {
        }
 }
 
+#ifdef HAVE_GETIFADDRS
+struct getifaddrs_in_netns_params {
+       struct ifaddrs **ifa;
+       int netns;
+};
+
+#ifdef HAVE_SETNS
+static void *getifaddrs_in_netns_thread(void *arg) {
+       struct getifaddrs_in_netns_params *params = arg;
+
+       if(setns(params->netns, CLONE_NEWNET) == -1) {
+               meshlink_errno = MESHLINK_EINVAL;
+               return NULL;
+       }
+
+       if(getifaddrs(params->ifa) != 0) {
+               *params->ifa = NULL;
+       }
+
+       return NULL;
+}
+#endif // HAVE_SETNS
+
+static int getifaddrs_in_netns(struct ifaddrs **ifa, int netns) {
+       if(netns == -1) {
+               return getifaddrs(ifa);
+       }
+
+#ifdef HAVE_SETNS
+       struct getifaddrs_in_netns_params params = {ifa, netns};
+       pthread_t thr;
+
+       if(pthread_create(&thr, NULL, getifaddrs_in_netns_thread, &params) == 0) {
+               if(pthread_join(thr, NULL) != 0) {
+                       abort();
+               }
+       }
+
+       return *params.ifa ? 0 : -1;
+#else
+       return -1;
+#endif // HAVE_SETNS
+
+}
+#endif
+
 char *meshlink_get_local_address_for_family(meshlink_handle_t *mesh, int family) {
        (void)mesh;
 
@@ -361,7 +407,7 @@ char *meshlink_get_local_address_for_family(meshlink_handle_t *mesh, int family)
 
        if(!success) {
                struct ifaddrs *ifa = NULL;
-               getifaddrs(&ifa);
+               getifaddrs_in_netns(&ifa, mesh->netns);
 
                for(struct ifaddrs *ifap = ifa; ifap; ifap = ifap->ifa_next) {
                        sockaddr_t *sa = (sockaddr_t *)ifap->ifa_addr;