net: qrtr: Allow non-immediate node routing

In order to reach non-immediate remote node services that are
accessed through an intermediate node, the route to the remote
node needs to be saved.

E.g for a [node1 <=> node2 <=> node3] network
- node2 forwards node3 service to node1
- node1 must save node2 as route for reaching node3
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/qrtr/qrtr.c

@@ -401,12 +401,13 @@ static void qrtr_node_assign(struct qrtr_node *node, unsigned int nid)
 {
 	unsigned long flags;
 
-	if (node->nid != QRTR_EP_NID_AUTO || nid == QRTR_EP_NID_AUTO)
+	if (nid == QRTR_EP_NID_AUTO)
 		return;
 
 	spin_lock_irqsave(&qrtr_nodes_lock, flags);
 	radix_tree_insert(&qrtr_nodes, nid, node);
-	node->nid = nid;
+	if (node->nid == QRTR_EP_NID_AUTO)
+		node->nid = nid;
 	spin_unlock_irqrestore(&qrtr_nodes_lock, flags);
 }
 
@@ -494,6 +495,13 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
 
 	qrtr_node_assign(node, cb->src_node);
 
+	if (cb->type == QRTR_TYPE_NEW_SERVER) {
+		/* Remote node endpoint can bridge other distant nodes */
+		const struct qrtr_ctrl_pkt *pkt = data + hdrlen;
+
+		qrtr_node_assign(node, le32_to_cpu(pkt->server.node));
+	}
+
 	if (cb->type == QRTR_TYPE_RESUME_TX) {
 		qrtr_tx_resume(node, skb);
 	} else {