Merge branch 'net-qrtr-add-distant-node-support'

Loic Poulain says:

====================
net: qrtr: Add distant node support

QRTR protocol allows a node to communicate with an other non-immediate
node via an intermdediate immediate node acting as a 'bridge':

node-0 <=> node-1 <=> node-2

This is currently not supported in this upstream version and this
series aim to fix that.

This series is V2 because changes 1, 2 and 3 have already been submitted
separately on LKML.

Changes in v2:
- Add reviewed-by tags from Bjorn and Mani
- Fixing checkpatch issue reported by Jakub
====================

Link: https://lore.kernel.org/r/1604684010-24090-1-git-send-email-loic.poulain@linaro.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/qrtr/ns.c

@@ -517,10 +517,6 @@ static int ctrl_cmd_new_server(struct sockaddr_qrtr *from,
 		port = from->sq_port;
 	}
 
-	/* Don't accept spoofed messages */
-	if (from->sq_node != node_id)
-		return -EINVAL;
-
 	srv = server_add(service, instance, node_id, port);
 	if (!srv)
 		return -EINVAL;
@@ -559,10 +555,6 @@ static int ctrl_cmd_del_server(struct sockaddr_qrtr *from,
 		port = from->sq_port;
 	}
 
-	/* Don't accept spoofed messages */
-	if (from->sq_node != node_id)
-		return -EINVAL;
-
 	/* Local servers may only unregister themselves */
 	if (from->sq_node == qrtr_ns.local_node && from->sq_port != port)
 		return -EINVAL;

net/qrtr/qrtr.c

@@ -171,8 +171,13 @@ static void __qrtr_node_release(struct kref *kref)
 	void __rcu **slot;
 
 	spin_lock_irqsave(&qrtr_nodes_lock, flags);
-	if (node->nid != QRTR_EP_NID_AUTO)
-		radix_tree_delete(&qrtr_nodes, node->nid);
+	/* If the node is a bridge for other nodes, there are possibly
+	 * multiple entries pointing to our released node, delete them all.
+	 */
+	radix_tree_for_each_slot(slot, &qrtr_nodes, &iter, 0) {
+		if (*slot == node)
+			radix_tree_iter_delete(&qrtr_nodes, &iter, slot);
+	}
 	spin_unlock_irqrestore(&qrtr_nodes_lock, flags);
 
 	list_del(&node->item);
@@ -347,7 +352,7 @@ static int qrtr_node_enqueue(struct qrtr_node *node, struct sk_buff *skb,
 	hdr->src_port_id = cpu_to_le32(from->sq_port);
 	if (to->sq_port == QRTR_PORT_CTRL) {
 		hdr->dst_node_id = cpu_to_le32(node->nid);
-		hdr->dst_port_id = cpu_to_le32(QRTR_NODE_BCAST);
+		hdr->dst_port_id = cpu_to_le32(QRTR_PORT_CTRL);
 	} else {
 		hdr->dst_node_id = cpu_to_le32(to->sq_node);
 		hdr->dst_port_id = cpu_to_le32(to->sq_port);
@@ -401,12 +406,13 @@ 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 +500,13 @@ 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 {
@@ -519,18 +532,20 @@ EXPORT_SYMBOL_GPL(qrtr_endpoint_post);
 /**
  * qrtr_alloc_ctrl_packet() - allocate control packet skb
  * @pkt: reference to qrtr_ctrl_pkt pointer
+ * @flags: the type of memory to allocate
  *
  * Returns newly allocated sk_buff, or NULL on failure
  *
  * This function allocates a sk_buff large enough to carry a qrtr_ctrl_pkt and
  * on success returns a reference to the control packet in @pkt.
  */
-static struct sk_buff *qrtr_alloc_ctrl_packet(struct qrtr_ctrl_pkt **pkt)
+static struct sk_buff *qrtr_alloc_ctrl_packet(struct qrtr_ctrl_pkt **pkt,
+					      gfp_t flags)
 {
 	const int pkt_len = sizeof(struct qrtr_ctrl_pkt);
 	struct sk_buff *skb;
 
-	skb = alloc_skb(QRTR_HDR_MAX_SIZE + pkt_len, GFP_KERNEL);
+	skb = alloc_skb(QRTR_HDR_MAX_SIZE + pkt_len, flags);
 	if (!skb)
 		return NULL;
 
@@ -592,6 +607,7 @@ void qrtr_endpoint_unregister(struct qrtr_endpoint *ep)
 	struct qrtr_ctrl_pkt *pkt;
 	struct qrtr_tx_flow *flow;
 	struct sk_buff *skb;
+	unsigned long flags;
 	void __rcu **slot;
 
 	mutex_lock(&node->ep_lock);
@@ -599,11 +615,18 @@ void qrtr_endpoint_unregister(struct qrtr_endpoint *ep)
 	mutex_unlock(&node->ep_lock);
 
 	/* Notify the local controller about the event */
-	skb = qrtr_alloc_ctrl_packet(&pkt);
-	if (skb) {
-		pkt->cmd = cpu_to_le32(QRTR_TYPE_BYE);
-		qrtr_local_enqueue(NULL, skb, QRTR_TYPE_BYE, &src, &dst);
+	spin_lock_irqsave(&qrtr_nodes_lock, flags);
+	radix_tree_for_each_slot(slot, &qrtr_nodes, &iter, 0) {
+		if (*slot != node)
+			continue;
+		src.sq_node = iter.index;
+		skb = qrtr_alloc_ctrl_packet(&pkt, GFP_ATOMIC);
+		if (skb) {
+			pkt->cmd = cpu_to_le32(QRTR_TYPE_BYE);
+			qrtr_local_enqueue(NULL, skb, QRTR_TYPE_BYE, &src, &dst);
+		}
 	}
+	spin_unlock_irqrestore(&qrtr_nodes_lock, flags);
 
 	/* Wake up any transmitters waiting for resume-tx from the node */
 	mutex_lock(&node->qrtr_tx_lock);
@@ -656,7 +679,7 @@ static void qrtr_port_remove(struct qrtr_sock *ipc)
 	to.sq_node = QRTR_NODE_BCAST;
 	to.sq_port = QRTR_PORT_CTRL;
 
-	skb = qrtr_alloc_ctrl_packet(&pkt);
+	skb = qrtr_alloc_ctrl_packet(&pkt, GFP_KERNEL);
 	if (skb) {
 		pkt->cmd = cpu_to_le32(QRTR_TYPE_DEL_CLIENT);
 		pkt->client.node = cpu_to_le32(ipc->us.sq_node);
@@ -982,7 +1005,7 @@ static int qrtr_send_resume_tx(struct qrtr_cb *cb)
 	if (!node)
 		return -EINVAL;
 
-	skb = qrtr_alloc_ctrl_packet(&pkt);
+	skb = qrtr_alloc_ctrl_packet(&pkt, GFP_KERNEL);
 	if (!skb)
 		return -ENOMEM;