NFC: LLCP raw socket support

This adds support for socket of type SOCK_RAW to LLCP.
sk_buff are copied and sent to raw sockets with a 2 bytes extra header:
The first byte header contains the nfc adapter index.
The second one contains flags:
- 0x01 - Direction (0=RX, 1=TX)
- 0x02-0x80 - Reserved
A raw socket has to be explicitly bound to a nfc adapter. This is achieved
by specifying the adapter index to be bound to in the dev_idx field of the
sockaddr_nfc_llcp struct passed to bind().
Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

include/linux/nfc.h

@@ -183,4 +183,15 @@ struct sockaddr_nfc_llcp {
 
 #define NFC_HEADER_SIZE 1
 
+/**
+ * Pseudo-header info for raw socket packets
+ * First byte is the adapter index
+ * Second byte contains flags
+ *  - 0x01 - Direction (0=RX, 1=TX)
+ *  - 0x02-0x80 - Reserved
+ **/
+#define NFC_LLCP_RAW_HEADER_SIZE	2
+#define NFC_LLCP_DIRECTION_RX		0x00
+#define NFC_LLCP_DIRECTION_TX		0x01
+
 #endif /*__LINUX_NFC_H */

net/nfc/llcp/commands.c

@@ -312,6 +312,8 @@ int nfc_llcp_send_symm(struct nfc_dev *dev)
 
 	skb = llcp_add_header(skb, 0, 0, LLCP_PDU_SYMM);
 
+	nfc_llcp_send_to_raw_sock(local, skb, NFC_LLCP_DIRECTION_TX);
+
 	return nfc_data_exchange(dev, local->target_idx, skb,
 				 nfc_llcp_recv, local);
 }

net/nfc/llcp/llcp.c

@@ -558,6 +558,46 @@ static void nfc_llcp_set_nrns(struct nfc_llcp_sock *sock, struct sk_buff *pdu)
 	sock->recv_ack_n = (sock->recv_n - 1) % 16;
 }
 
+void nfc_llcp_send_to_raw_sock(struct nfc_llcp_local *local,
+			       struct sk_buff *skb, u8 direction)
+{
+	struct hlist_node *node;
+	struct sk_buff *skb_copy = NULL, *nskb;
+	struct sock *sk;
+	u8 *data;
+
+	read_lock(&local->raw_sockets.lock);
+
+	sk_for_each(sk, node, &local->raw_sockets.head) {
+		if (sk->sk_state != LLCP_BOUND)
+			continue;
+
+		if (skb_copy == NULL) {
+			skb_copy = __pskb_copy(skb, NFC_LLCP_RAW_HEADER_SIZE,
+					       GFP_ATOMIC);
+
+			if (skb_copy == NULL)
+				continue;
+
+			data = skb_push(skb_copy, NFC_LLCP_RAW_HEADER_SIZE);
+
+			data[0] = local->dev ? local->dev->idx : 0xFF;
+			data[1] = direction;
+		}
+
+		nskb = skb_clone(skb_copy, GFP_ATOMIC);
+		if (!nskb)
+			continue;
+
+		if (sock_queue_rcv_skb(sk, nskb))
+			kfree_skb(nskb);
+	}
+
+	read_unlock(&local->raw_sockets.lock);
+
+	kfree_skb(skb_copy);
+}
+
 static void nfc_llcp_tx_work(struct work_struct *work)
 {
 	struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
@@ -578,6 +618,9 @@ static void nfc_llcp_tx_work(struct work_struct *work)
 				       DUMP_PREFIX_OFFSET, 16, 1,
 				       skb->data, skb->len, true);
 
+			nfc_llcp_send_to_raw_sock(local, skb,
+						  NFC_LLCP_DIRECTION_TX);
+
 			ret = nfc_data_exchange(local->dev, local->target_idx,
 						skb, nfc_llcp_recv, local);
 
@@ -1022,6 +1065,8 @@ static void nfc_llcp_rx_work(struct work_struct *work)
 		print_hex_dump(KERN_DEBUG, "LLCP Rx: ", DUMP_PREFIX_OFFSET,
 			       16, 1, skb->data, skb->len, true);
 
+	nfc_llcp_send_to_raw_sock(local, skb, NFC_LLCP_DIRECTION_RX);
+
 	switch (ptype) {
 	case LLCP_PDU_SYMM:
 		pr_debug("SYMM\n");
@@ -1158,6 +1203,7 @@ int nfc_llcp_register_device(struct nfc_dev *ndev)
 
 	rwlock_init(&local->sockets.lock);
 	rwlock_init(&local->connecting_sockets.lock);
+	rwlock_init(&local->raw_sockets.lock);
 
 	nfc_llcp_build_gb(local);
 

net/nfc/llcp/llcp.h

@@ -86,6 +86,7 @@ struct nfc_llcp_local {
 	/* sockets array */
 	struct llcp_sock_list sockets;
 	struct llcp_sock_list connecting_sockets;
+	struct llcp_sock_list raw_sockets;
 };
 
 struct nfc_llcp_sock {
@@ -184,6 +185,8 @@ u8 nfc_llcp_get_sdp_ssap(struct nfc_llcp_local *local,
 u8 nfc_llcp_get_local_ssap(struct nfc_llcp_local *local);
 void nfc_llcp_put_ssap(struct nfc_llcp_local *local, u8 ssap);
 int nfc_llcp_queue_i_frames(struct nfc_llcp_sock *sock);
+void nfc_llcp_send_to_raw_sock(struct nfc_llcp_local *local,
+			       struct sk_buff *skb, u8 direction);
 
 /* Sock API */
 struct sock *nfc_llcp_sock_alloc(struct socket *sock, int type, gfp_t gfp);

net/nfc/llcp/sock.c

@@ -142,6 +142,60 @@ static int llcp_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
 	return ret;
 }
 
+static int llcp_raw_sock_bind(struct socket *sock, struct sockaddr *addr,
+			      int alen)
+{
+	struct sock *sk = sock->sk;
+	struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
+	struct nfc_llcp_local *local;
+	struct nfc_dev *dev;
+	struct sockaddr_nfc_llcp llcp_addr;
+	int len, ret = 0;
+
+	if (!addr || addr->sa_family != AF_NFC)
+		return -EINVAL;
+
+	pr_debug("sk %p addr %p family %d\n", sk, addr, addr->sa_family);
+
+	memset(&llcp_addr, 0, sizeof(llcp_addr));
+	len = min_t(unsigned int, sizeof(llcp_addr), alen);
+	memcpy(&llcp_addr, addr, len);
+
+	lock_sock(sk);
+
+	if (sk->sk_state != LLCP_CLOSED) {
+		ret = -EBADFD;
+		goto error;
+	}
+
+	dev = nfc_get_device(llcp_addr.dev_idx);
+	if (dev == NULL) {
+		ret = -ENODEV;
+		goto error;
+	}
+
+	local = nfc_llcp_find_local(dev);
+	if (local == NULL) {
+		ret = -ENODEV;
+		goto put_dev;
+	}
+
+	llcp_sock->dev = dev;
+	llcp_sock->local = nfc_llcp_local_get(local);
+	llcp_sock->nfc_protocol = llcp_addr.nfc_protocol;
+
+	nfc_llcp_sock_link(&local->raw_sockets, sk);
+
+	sk->sk_state = LLCP_BOUND;
+
+put_dev:
+	nfc_put_device(dev);
+
+error:
+	release_sock(sk);
+	return ret;
+}
+
 static int llcp_sock_listen(struct socket *sock, int backlog)
 {
 	struct sock *sk = sock->sk;
@@ -418,7 +472,10 @@ static int llcp_sock_release(struct socket *sock)
 
 	release_sock(sk);
 
-	nfc_llcp_sock_unlink(&local->sockets, sk);
+	if (sock->type == SOCK_RAW)
+		nfc_llcp_sock_unlink(&local->raw_sockets, sk);
+	else
+		nfc_llcp_sock_unlink(&local->sockets, sk);
 
 out:
 	sock_orphan(sk);
@@ -614,7 +671,7 @@ static int llcp_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
 	if (!(flags & MSG_PEEK)) {
 
 		/* SOCK_STREAM: re-queue skb if it contains unreceived data */
-		if (sk->sk_type == SOCK_STREAM) {
+		if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_RAW) {
 			skb_pull(skb, copied);
 			if (skb->len) {
 				skb_queue_head(&sk->sk_receive_queue, skb);
@@ -655,6 +712,26 @@ static const struct proto_ops llcp_sock_ops = {
 	.mmap           = sock_no_mmap,
 };
 
+static const struct proto_ops llcp_rawsock_ops = {
+	.family         = PF_NFC,
+	.owner          = THIS_MODULE,
+	.bind           = llcp_raw_sock_bind,
+	.connect        = sock_no_connect,
+	.release        = llcp_sock_release,
+	.socketpair     = sock_no_socketpair,
+	.accept         = sock_no_accept,
+	.getname        = llcp_sock_getname,
+	.poll           = llcp_sock_poll,
+	.ioctl          = sock_no_ioctl,
+	.listen         = sock_no_listen,
+	.shutdown       = sock_no_shutdown,
+	.setsockopt     = sock_no_setsockopt,
+	.getsockopt     = sock_no_getsockopt,
+	.sendmsg        = sock_no_sendmsg,
+	.recvmsg        = llcp_sock_recvmsg,
+	.mmap           = sock_no_mmap,
+};
+
 static void llcp_sock_destruct(struct sock *sk)
 {
 	struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
@@ -732,10 +809,15 @@ static int llcp_sock_create(struct net *net, struct socket *sock,
 
 	pr_debug("%p\n", sock);
 
-	if (sock->type != SOCK_STREAM && sock->type != SOCK_DGRAM)
+	if (sock->type != SOCK_STREAM &&
+	    sock->type != SOCK_DGRAM &&
+	    sock->type != SOCK_RAW)
 		return -ESOCKTNOSUPPORT;
 
-	sock->ops = &llcp_sock_ops;
+	if (sock->type == SOCK_RAW)
+		sock->ops = &llcp_rawsock_ops;
+	else
+		sock->ops = &llcp_sock_ops;
 
 	sk = nfc_llcp_sock_alloc(sock, sock->type, GFP_ATOMIC);
 	if (sk == NULL)