Allow the mesh to detect when a node has completely restarted.

When calling meshlink_open(), a node creates a unique ID that is passed
along ADD_EDGE messages. When a node becomes unreachable and then reachable
again, this allows other nodes to detect whether it was just a temporary
network issue, or whether the node completely restarted (either because
meshlink_close() was called or because it crashed).

At the moment, when this is detected, other nodes close all open channels
with the restarted node.

diff --git a/src/edge.h b/src/edge.h
index 2e59fa1de02da0a411787b82359ed855935c9dd5..ba18e875df95108ef1bfa49c8c0f080868295831 100644 (file)
--- a/src/edge.h
+++ b/src/edge.h
@@ -34,6 +34,7 @@ typedef struct edge_t {
        struct edge_t *reverse;                 /* edge in the opposite direction, if available */
 
        int weight;                             /* weight of this edge */
+       uint32_t session_id;                     /* the session_id of the from node */
 } edge_t;
 
 extern void init_edges(struct meshlink_handle *mesh);

diff --git a/src/graph.c b/src/graph.c
index 60ac3adfc362a50806ac93b3b5e44850813f2ef7..d86ac4a81e3ea560e8a14f15b9180399570d3d0a 100644 (file)
--- a/src/graph.c
+++ b/src/graph.c
@@ -196,6 +196,15 @@ static void check_reachability(meshlink_handle_t *mesh) {
        /* Check reachability status. */
 
        for splay_each(node_t, n, mesh->nodes) {
+               /* Check for nodes that have changed session_id */
+               if(n->status.visited && n->prevedge && n->prevedge->reverse->session_id != n->session_id) {
+                       n->session_id = n->prevedge->reverse->session_id;
+
+                       if(n->utcp) {
+                               utcp_abort_all_connections(n->utcp);
+                       }
+               }
+
                if(n->status.visited != n->status.reachable) {
                        n->status.reachable = !n->status.reachable;
                        n->last_state_change = mesh->loop.now.tv_sec;

diff --git a/src/meshlink.c b/src/meshlink.c
index f1b6a334c6a7bb90bd6be8018a90b861a65a2842..0318a497ba98bc4a30549898c72ccbd19b12ef81 100644 (file)
--- a/src/meshlink.c
+++ b/src/meshlink.c
@@ -889,6 +889,7 @@ static bool meshlink_setup(meshlink_handle_t *mesh) {
        mesh->self->name = xstrdup(mesh->name);
        mesh->self->devclass = mesh->devclass;
        mesh->self->ecdsa = ecdsa_set_public_key(ecdsa_get_public_key(mesh->private_key));
+       mesh->self->session_id = mesh->session_id;
 
        if(!write_main_config_files(mesh)) {
                logger(mesh, MESHLINK_ERROR, "Could not write main config files into %s/current: %s\n", mesh->confbase, strerror(errno));
@@ -967,6 +968,7 @@ static bool meshlink_read_config(meshlink_handle_t *mesh) {
        mesh->self = new_node();
        mesh->self->name = xstrdup(name);
        mesh->self->devclass = mesh->devclass;
+       mesh->self->session_id = mesh->session_id;
 
        if(!node_read_public_key(mesh, mesh->self)) {
                logger(NULL, MESHLINK_ERROR, "Could not read our host configuration file!");
@@ -1288,6 +1290,10 @@ meshlink_handle_t *meshlink_open_ex(const meshlink_open_params_t *params) {
 
        randomize(&mesh->prng_state, sizeof(mesh->prng_state));
 
+       do {
+               randomize(&mesh->session_id, sizeof(mesh->session_id));
+       } while(mesh->session_id == 0);
+
        memcpy(mesh->dev_class_traits, default_class_traits, sizeof(default_class_traits));
 
        if(usingname) {
@@ -2221,6 +2227,7 @@ bool meshlink_set_port(meshlink_handle_t *mesh, int port) {
        mesh->self = new_node();
        mesh->self->name = xstrdup(mesh->name);
        mesh->self->devclass = mesh->devclass;
+       mesh->self->session_id = mesh->session_id;
        xasprintf(&mesh->myport, "%d", port);
 
        if(!node_read_public_key(mesh, mesh->self)) {

diff --git a/src/meshlink_internal.h b/src/meshlink_internal.h
index dd8c7d329f38929e499d3c5b935ba2594d00862f..bad5825591968f4d5bba0ebe88f42108bc70bbc6 100644 (file)
--- a/src/meshlink_internal.h
+++ b/src/meshlink_internal.h
@@ -133,6 +133,7 @@ struct meshlink_handle {
 
        struct connection_t *everyone;
        uint64_t prng_state[4];
+       uint32_t session_id;
 
        int next_pit;
        int pits[10];

diff --git a/src/node.h b/src/node.h
index e42aac4a4d894f02d4a840408c029aceda1d8349..50ee141c6cba88b42e74b1f0fe400ff2e6fe1972 100644 (file)
--- a/src/node.h
+++ b/src/node.h
@@ -50,8 +50,9 @@ typedef struct node_t {
        dev_class_t devclass;
 
        // Used for packet I/O
-       sptps_t sptps;
        int sock;                               /* Socket to use for outgoing UDP packets */
+       uint32_t session_id;                    /* Unique ID for this node's currently running process */
+       sptps_t sptps;
        sockaddr_t address;                     /* his real (internet) ip to send UDP packets to */
 
        struct utcp *utcp;

diff --git a/src/protocol_edge.c b/src/protocol_edge.c
index e817114b3b8072690a21fcfbd97f9717799a4a57..6be658ee56fda5eee86901c99280bf9bab6d2295 100644 (file)
--- a/src/protocol_edge.c
+++ b/src/protocol_edge.c
@@ -74,9 +74,9 @@ bool send_add_edge(meshlink_handle_t *mesh, connection_t *c, const edge_t *e, in
                s = e->to->submesh;
        }
 
-       x = send_request(mesh, c, s, "%d %x %s %d %s %s %s %s %d %s %x %d %d", ADD_EDGE, prng(mesh, UINT_MAX),
+       x = send_request(mesh, c, s, "%d %x %s %d %s %s %s %s %d %s %x %d %d %x", ADD_EDGE, prng(mesh, UINT_MAX),
                         e->from->name, e->from->devclass, from_submesh, e->to->name, address, port,
-                        e->to->devclass, to_submesh, OPTION_PMTU_DISCOVERY, e->weight, contradictions);
+                        e->to->devclass, to_submesh, OPTION_PMTU_DISCOVERY, e->weight, contradictions, e->from->session_id);
        free(address);
        free(port);
 
@@ -100,11 +100,12 @@ bool add_edge_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
        sockaddr_t address;
        int weight;
        int contradictions = 0;
+       uint32_t session_id = 0;
        submesh_t *s = NULL;
 
-       if(sscanf(request, "%*d %*x "MAX_STRING" %d "MAX_STRING" "MAX_STRING" "MAX_STRING" "MAX_STRING" %d "MAX_STRING" %*x %d %d",
+       if(sscanf(request, "%*d %*x "MAX_STRING" %d "MAX_STRING" "MAX_STRING" "MAX_STRING" "MAX_STRING" %d "MAX_STRING" %*x %d %d %x",
                        from_name, &from_devclass, from_submesh_name, to_name, to_address, to_port, &to_devclass, to_submesh_name,
-                       &weight, &contradictions) < 9) {
+                       &weight, &contradictions, &session_id) < 9) {
                logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "ADD_EDGE", c->name);
                return false;
        }
@@ -164,6 +165,10 @@ bool add_edge_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
 
        from->devclass = from_devclass;
 
+       if(!from->session_id) {
+               from->session_id = session_id;
+       }
+
        if(!to) {
                to = new_node();
                to->status.dirty = true;
@@ -194,7 +199,7 @@ bool add_edge_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
        e = lookup_edge(from, to);
 
        if(e) {
-               if(e->weight != weight || sockaddrcmp(&e->address, &address)) {
+               if(e->weight != weight || e->session_id != session_id || sockaddrcmp(&e->address, &address)) {
                        if(from == mesh->self) {
                                logger(mesh, MESHLINK_WARNING, "Got %s from %s for ourself which does not match existing entry",
                                       "ADD_EDGE", c->name);
@@ -215,6 +220,7 @@ bool add_edge_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
                e = new_edge();
                e->from = from;
                e->to = to;
+               e->session_id = session_id;
                send_del_edge(mesh, c, e, mesh->contradicting_add_edge);
                free_edge(e);
                return true;
@@ -225,6 +231,7 @@ bool add_edge_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
        e->to = to;
        e->address = address;
        e->weight = weight;
+       e->session_id = session_id;
        edge_add(mesh, e);
 
        /* Run MST before or after we tell the rest? */
@@ -273,8 +280,8 @@ bool send_del_edge(meshlink_handle_t *mesh, connection_t *c, const edge_t *e, in
                s = e->to->submesh;
        }
 
-       return send_request(mesh, c, s, "%d %x %s %s %d", DEL_EDGE, prng(mesh, UINT_MAX),
-                           e->from->name, e->to->name, contradictions);
+       return send_request(mesh, c, s, "%d %x %s %s %d %x", DEL_EDGE, prng(mesh, UINT_MAX),
+                           e->from->name, e->to->name, contradictions, e->session_id);
 }
 
 bool del_edge_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
@@ -286,9 +293,10 @@ bool del_edge_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
        char to_name[MAX_STRING_SIZE];
        node_t *from, *to;
        int contradictions = 0;
+       uint32_t session_id = 0;
        submesh_t *s = NULL;
 
-       if(sscanf(request, "%*d %*x "MAX_STRING" "MAX_STRING" %d", from_name, to_name, &contradictions) < 2) {
+       if(sscanf(request, "%*d %*x "MAX_STRING" "MAX_STRING" %d %x", from_name, to_name, &contradictions, &session_id) < 2) {
                logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "DEL_EDGE", c->name);
                return false;
        }

diff --git a/test/channels-failure.c b/test/channels-failure.c
index 18aef2d5e3453ae300170f001f8ce04f3dd984ee..5c98005575cc803f477c3bd9d7cf9637dbabfb42 100644 (file)
--- a/test/channels-failure.c
+++ b/test/channels-failure.c
@@ -87,8 +87,8 @@ int main() {
 
        // Try setting up a new channel while b is still down.
 
-       poll_flag.flag = false;
-       receive_flag.flag = false;
+       set_sync_flag(&poll_flag, false);
+       set_sync_flag(&receive_flag, false);
 
        channel = meshlink_channel_open(mesh_a, b, 7, NULL, NULL, 0);
        assert(channel);
@@ -98,6 +98,33 @@ int main() {
        assert(wait_sync_flag(&poll_flag, 5));
        assert(poll_len == 0);
 
+       meshlink_channel_close(mesh_a, channel);
+
+       // Restart b and create a new channel
+
+       set_sync_flag(&poll_flag, false);
+       set_sync_flag(&receive_flag, false);
+
+       meshlink_set_node_channel_timeout(mesh_a, b, 60);
+
+       assert(meshlink_start(mesh_b));
+
+       channel = meshlink_channel_open(mesh_a, b, 7, receive_cb, NULL, 0);
+       meshlink_set_channel_poll_cb(mesh_a, channel, poll_cb);
+       assert(channel);
+       assert(wait_sync_flag(&poll_flag, 10));
+       assert(poll_len != 0);
+
+       // Close and reopen b, we should get a fast notification that the channel has been closed.
+
+       meshlink_close(mesh_b);
+       mesh_b = meshlink_open("channels_failure_conf.2", "b", "channels_failure", DEV_CLASS_BACKBONE);
+       assert(mesh_b);
+       assert(meshlink_start(mesh_b));
+
+       assert(wait_sync_flag(&receive_flag, 10));
+       assert(receive_len == 0);
+
        // Clean up.
 
        close_meshlink_pair(mesh_a, mesh_b);