NFC: llcp: Service Name Lookup netlink interface

This adds a netlink interface for service name lookup support.
Multiple URIs can be passed nested into the NFC_ATTR_LLC_SDP attribute
using the NFC_CMD_LLC_SDREQ netlink command.
When the SNL reply is received, a NFC_EVENT_LLC_SDRES event is sent to
the user space. URI and SAP tuples are passed back, nested into
NFC_ATTR_LLC_SDP attribute.

Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

net/nfc/llcp/commands.c

@@ -144,12 +144,59 @@ struct nfc_llcp_sdp_tlv *nfc_llcp_build_sdres_tlv(u8 tid, u8 sap)
 	return sdres;
 }
 
+struct nfc_llcp_sdp_tlv *nfc_llcp_build_sdreq_tlv(u8 tid, char *uri,
+						  size_t uri_len)
+{
+	struct nfc_llcp_sdp_tlv *sdreq;
+
+	pr_debug("uri: %s, len: %zu\n", uri, uri_len);
+
+	sdreq = kzalloc(sizeof(struct nfc_llcp_sdp_tlv), GFP_KERNEL);
+	if (sdreq == NULL)
+		return NULL;
+
+	sdreq->tlv_len = uri_len + 3;
+
+	if (uri[uri_len - 1] == 0)
+		sdreq->tlv_len--;
+
+	sdreq->tlv = kzalloc(sdreq->tlv_len + 1, GFP_KERNEL);
+	if (sdreq->tlv == NULL) {
+		kfree(sdreq);
+		return NULL;
+	}
+
+	sdreq->tlv[0] = LLCP_TLV_SDREQ;
+	sdreq->tlv[1] = sdreq->tlv_len - 2;
+	sdreq->tlv[2] = tid;
+
+	sdreq->tid = tid;
+	sdreq->uri = sdreq->tlv + 3;
+	memcpy(sdreq->uri, uri, uri_len);
+
+	INIT_HLIST_NODE(&sdreq->node);
+
+	return sdreq;
+}
+
 void nfc_llcp_free_sdp_tlv(struct nfc_llcp_sdp_tlv *sdp)
 {
 	kfree(sdp->tlv);
 	kfree(sdp);
 }
 
+void nfc_llcp_free_sdp_tlv_list(struct hlist_head *head)
+{
+	struct nfc_llcp_sdp_tlv *sdp;
+	struct hlist_node *n;
+
+	hlist_for_each_entry_safe(sdp, n, head, node) {
+		hlist_del(&sdp->node);
+
+		nfc_llcp_free_sdp_tlv(sdp);
+	}
+}
+
 int nfc_llcp_parse_gb_tlv(struct nfc_llcp_local *local,
 			  u8 *tlv_array, u16 tlv_array_len)
 {
@@ -511,6 +558,37 @@ int nfc_llcp_send_snl_sdres(struct nfc_llcp_local *local,
 	return 0;
 }
 
+int nfc_llcp_send_snl_sdreq(struct nfc_llcp_local *local,
+			    struct hlist_head *tlv_list, size_t tlvs_len)
+{
+	struct nfc_llcp_sdp_tlv *sdreq;
+	struct hlist_node *n;
+	struct sk_buff *skb;
+
+	skb = nfc_llcp_allocate_snl(local, tlvs_len);
+	if (IS_ERR(skb))
+		return PTR_ERR(skb);
+
+	mutex_lock(&local->sdreq_lock);
+
+	hlist_for_each_entry_safe(sdreq, n, tlv_list, node) {
+		pr_debug("tid %d for %s\n", sdreq->tid, sdreq->uri);
+
+		memcpy(skb_put(skb, sdreq->tlv_len), sdreq->tlv,
+		       sdreq->tlv_len);
+
+		hlist_del(&sdreq->node);
+
+		hlist_add_head(&sdreq->node, &local->pending_sdreqs);
+	}
+
+	mutex_unlock(&local->sdreq_lock);
+
+	skb_queue_tail(&local->tx_queue, skb);
+
+	return 0;
+}
+
 int nfc_llcp_send_dm(struct nfc_llcp_local *local, u8 ssap, u8 dsap, u8 reason)
 {
 	struct sk_buff *skb;

net/nfc/llcp/llcp.c

@@ -156,6 +156,7 @@ static void local_release(struct kref *ref)
 	cancel_work_sync(&local->rx_work);
 	cancel_work_sync(&local->timeout_work);
 	kfree_skb(local->rx_pending);
+	nfc_llcp_free_sdp_tlv_list(&local->pending_sdreqs);
 	kfree(local);
 }
 
@@ -1147,6 +1148,7 @@ static void nfc_llcp_recv_snl(struct nfc_llcp_local *local,
 	struct nfc_llcp_sdp_tlv *sdp;
 	HLIST_HEAD(llc_sdres_list);
 	size_t sdres_tlvs_len;
+	HLIST_HEAD(nl_sdres_list);
 
 	dsap = nfc_llcp_dsap(skb);
 	ssap = nfc_llcp_ssap(skb);
@@ -1229,6 +1231,30 @@ add_snl:
 			hlist_add_head(&sdp->node, &llc_sdres_list);
 			break;
 
+		case LLCP_TLV_SDRES:
+			mutex_lock(&local->sdreq_lock);
+
+			pr_debug("LLCP_TLV_SDRES: searching tid %d\n", tlv[2]);
+
+			hlist_for_each_entry(sdp, &local->pending_sdreqs, node) {
+				if (sdp->tid != tlv[2])
+					continue;
+
+				sdp->sap = tlv[3];
+
+				pr_debug("Found: uri=%s, sap=%d\n",
+					 sdp->uri, sdp->sap);
+
+				hlist_del(&sdp->node);
+
+				hlist_add_head(&sdp->node, &nl_sdres_list);
+
+				break;
+			}
+
+			mutex_unlock(&local->sdreq_lock);
+			break;
+
 		default:
 			pr_err("Invalid SNL tlv value 0x%x\n", type);
 			break;
@@ -1239,6 +1265,9 @@ add_snl:
 	}
 
 exit:
+	if (!hlist_empty(&nl_sdres_list))
+		nfc_genl_llc_send_sdres(local->dev, &nl_sdres_list);
+
 	if (!hlist_empty(&llc_sdres_list))
 		nfc_llcp_send_snl_sdres(local, &llc_sdres_list, sdres_tlvs_len);
 }
@@ -1426,6 +1455,9 @@ int nfc_llcp_register_device(struct nfc_dev *ndev)
 	local->remote_miu = LLCP_DEFAULT_MIU;
 	local->remote_lto = LLCP_DEFAULT_LTO;
 
+	mutex_init(&local->sdreq_lock);
+	INIT_HLIST_HEAD(&local->pending_sdreqs);
+
 	list_add(&local->list, &llcp_devices);
 
 	return 0;

net/nfc/llcp/llcp.h

@@ -97,6 +97,10 @@ struct nfc_llcp_local {
 	u8  remote_opt;
 	u16 remote_wks;
 
+	struct mutex sdreq_lock;
+	struct hlist_head pending_sdreqs;
+	u8 sdreq_next_tid;
+
 	/* sockets array */
 	struct llcp_sock_list sockets;
 	struct llcp_sock_list connecting_sockets;
@@ -230,7 +234,10 @@ int nfc_llcp_parse_connection_tlv(struct nfc_llcp_sock *sock,
 void nfc_llcp_recv(void *data, struct sk_buff *skb, int err);
 u8 *nfc_llcp_build_tlv(u8 type, u8 *value, u8 value_length, u8 *tlv_length);
 struct nfc_llcp_sdp_tlv *nfc_llcp_build_sdres_tlv(u8 tid, u8 sap);
+struct nfc_llcp_sdp_tlv *nfc_llcp_build_sdreq_tlv(u8 tid, char *uri,
+						  size_t uri_len);
 void nfc_llcp_free_sdp_tlv(struct nfc_llcp_sdp_tlv *sdp);
+void nfc_llcp_free_sdp_tlv_list(struct hlist_head *sdp_head);
 void nfc_llcp_recv(void *data, struct sk_buff *skb, int err);
 int nfc_llcp_disconnect(struct nfc_llcp_sock *sock);
 int nfc_llcp_send_symm(struct nfc_dev *dev);
@@ -238,6 +245,8 @@ int nfc_llcp_send_connect(struct nfc_llcp_sock *sock);
 int nfc_llcp_send_cc(struct nfc_llcp_sock *sock);
 int nfc_llcp_send_snl_sdres(struct nfc_llcp_local *local,
 			    struct hlist_head *tlv_list, size_t tlvs_len);
+int nfc_llcp_send_snl_sdreq(struct nfc_llcp_local *local,
+			    struct hlist_head *tlv_list, size_t tlvs_len);
 int nfc_llcp_send_dm(struct nfc_llcp_local *local, u8 ssap, u8 dsap, u8 reason);
 int nfc_llcp_send_disconnect(struct nfc_llcp_sock *sock);
 int nfc_llcp_send_i_frame(struct nfc_llcp_sock *sock,