NFC: llcp: Add cleanup support for unreplied SNL requests

If the remote LLC doesn't reply in time to our SNL requests we remove
them from the list of pending requests. The timeout is fixed to an
arbitrary value of 3 times remote_lto.

When not replied, the local LLC broadcasts NFC_EVENT_LLC_SDRES nl events for
the concerned uris with sap values set to LLCP_SDP_UNBOUND (which is 65).
Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

net/nfc/llcp/commands.c

@@ -174,6 +174,8 @@ struct nfc_llcp_sdp_tlv *nfc_llcp_build_sdreq_tlv(u8 tid, char *uri,
 	sdreq->uri = sdreq->tlv + 3;
 	memcpy(sdreq->uri, uri, uri_len);
 
+	sdreq->time = jiffies;
+
 	INIT_HLIST_NODE(&sdreq->node);
 
 	return sdreq;
@@ -571,6 +573,10 @@ int nfc_llcp_send_snl_sdreq(struct nfc_llcp_local *local,
 
 	mutex_lock(&local->sdreq_lock);
 
+	if (hlist_empty(&local->pending_sdreqs))
+		mod_timer(&local->sdreq_timer,
+			  jiffies + msecs_to_jiffies(3 * local->remote_lto));
+
 	hlist_for_each_entry_safe(sdreq, n, tlv_list, node) {
 		pr_debug("tid %d for %s\n", sdreq->tid, sdreq->uri);
 

net/nfc/llcp/llcp.c

@@ -156,6 +156,8 @@ static void local_release(struct kref *ref)
 	cancel_work_sync(&local->rx_work);
 	cancel_work_sync(&local->timeout_work);
 	kfree_skb(local->rx_pending);
+	del_timer_sync(&local->sdreq_timer);
+	cancel_work_sync(&local->sdreq_timeout_work);
 	nfc_llcp_free_sdp_tlv_list(&local->pending_sdreqs);
 	kfree(local);
 }
@@ -224,6 +226,47 @@ static void nfc_llcp_symm_timer(unsigned long data)
 	schedule_work(&local->timeout_work);
 }
 
+static void nfc_llcp_sdreq_timeout_work(struct work_struct *work)
+{
+	unsigned long time;
+	HLIST_HEAD(nl_sdres_list);
+	struct hlist_node *n;
+	struct nfc_llcp_sdp_tlv *sdp;
+	struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
+						    sdreq_timeout_work);
+
+	mutex_lock(&local->sdreq_lock);
+
+	time = jiffies - msecs_to_jiffies(3 * local->remote_lto);
+
+	hlist_for_each_entry_safe(sdp, n, &local->pending_sdreqs, node) {
+		if (time_after(sdp->time, time))
+			continue;
+
+		sdp->sap = LLCP_SDP_UNBOUND;
+
+		hlist_del(&sdp->node);
+
+		hlist_add_head(&sdp->node, &nl_sdres_list);
+	}
+
+	if (!hlist_empty(&local->pending_sdreqs))
+		mod_timer(&local->sdreq_timer,
+			  jiffies + msecs_to_jiffies(3 * local->remote_lto));
+
+	mutex_unlock(&local->sdreq_lock);
+
+	if (!hlist_empty(&nl_sdres_list))
+		nfc_genl_llc_send_sdres(local->dev, &nl_sdres_list);
+}
+
+static void nfc_llcp_sdreq_timer(unsigned long data)
+{
+	struct nfc_llcp_local *local = (struct nfc_llcp_local *) data;
+
+	schedule_work(&local->sdreq_timeout_work);
+}
+
 struct nfc_llcp_local *nfc_llcp_find_local(struct nfc_dev *dev)
 {
 	struct nfc_llcp_local *local, *n;
@@ -1457,6 +1500,10 @@ int nfc_llcp_register_device(struct nfc_dev *ndev)
 
 	mutex_init(&local->sdreq_lock);
 	INIT_HLIST_HEAD(&local->pending_sdreqs);
+	init_timer(&local->sdreq_timer);
+	local->sdreq_timer.data = (unsigned long) local;
+	local->sdreq_timer.function = nfc_llcp_sdreq_timer;
+	INIT_WORK(&local->sdreq_timeout_work, nfc_llcp_sdreq_timeout_work);
 
 	list_add(&local->list, &llcp_devices);
 

net/nfc/llcp/llcp.h

@@ -54,6 +54,8 @@ struct nfc_llcp_sdp_tlv {
 	u8 tid;
 	u8 sap;
 
+	unsigned long time;
+
 	struct hlist_node node;
 };
 
@@ -99,6 +101,8 @@ struct nfc_llcp_local {
 
 	struct mutex sdreq_lock;
 	struct hlist_head pending_sdreqs;
+	struct timer_list sdreq_timer;
+	struct work_struct sdreq_timeout_work;
 	u8 sdreq_next_tid;
 
 	/* sockets array */