+ abort();
+ meshlink_handle_t *mesh = n->mesh;
+ if(!mesh->channel_accept_cb)
+ return;
+ meshlink_channel_t *channel = xzalloc(sizeof *channel);
+ channel->node = n;
+ channel->c = utcp_connection;
+ if(mesh->channel_accept_cb(mesh, channel, port, NULL, 0))
+ utcp_accept(utcp_connection, channel_recv, channel);
+ else
+ free(channel);
+}
+
+static ssize_t channel_send(struct utcp *utcp, const void *data, size_t len) {
+ node_t *n = utcp->priv;
+ meshlink_handle_t *mesh = n->mesh;
+ char hex[len * 2 + 1];
+ bin2hex(data, hex, len);
+ logger(mesh, MESHLINK_WARNING, "channel_send(%p, %p, %zu): %s\n", utcp, data, len, hex);
+ return meshlink_send(mesh, (meshlink_node_t *)n, data, len) ? len : -1;
+}
+
+void meshlink_set_channel_receive_cb(meshlink_handle_t *mesh, meshlink_channel_t *channel, meshlink_channel_receive_cb_t cb) {
+ if(!mesh || !channel) {
+ meshlink_errno = MESHLINK_EINVAL;
+ return;
+ }
+
+ channel->receive_cb = cb;
+}
+
+static void channel_receive(meshlink_handle_t *mesh, meshlink_node_t *source, const void *data, size_t len) {
+ node_t *n = (node_t *)source;
+ if(!n->utcp)
+ abort();
+ char hex[len * 2 + 1];
+ bin2hex(data, hex, len);
+ logger(mesh, MESHLINK_WARNING, "channel_receive(%p, %p, %zu): %s\n", n->utcp, data, len, hex);
+ utcp_recv(n->utcp, data, len);
+}
+
+static void channel_poll(struct utcp_connection *connection, size_t len) {
+ meshlink_channel_t *channel = connection->priv;
+ if(!channel)
+ abort();
+ node_t *n = channel->node;
+ meshlink_handle_t *mesh = n->mesh;
+ if(channel->poll_cb)
+ channel->poll_cb(mesh, channel, len);
+}
+
+void meshlink_set_channel_poll_cb(meshlink_handle_t *mesh, meshlink_channel_t *channel, meshlink_channel_poll_cb_t cb) {
+ channel->poll_cb = cb;
+ utcp_set_poll_cb(channel->c, cb ? channel_poll : NULL);
+}
+
+void meshlink_set_channel_accept_cb(meshlink_handle_t *mesh, meshlink_channel_accept_cb_t cb) {
+ if(!mesh) {
+ meshlink_errno = MESHLINK_EINVAL;