Commit 314001f0 authored by Rao Shoaib's avatar Rao Shoaib Committed by David S. Miller
Browse files

af_unix: Add OOB support 



This patch adds OOB support for AF_UNIX sockets.
The semantics is same as TCP.

The last byte of a message with the OOB flag is
treated as the OOB byte. The byte is separated into
a skb and a pointer to the skb is stored in unix_sock.
The pointer is used to enforce OOB semantics.

Signed-off-by: default avatarRao Shoaib <rao.shoaib@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7e89350c

include/net/af_unix.h

+3 −0
Original line number Diff line number Diff line
@@ -70,6 +70,9 @@ struct unix_sock { 
	struct socket_wq	peer_wq;

	wait_queue_entry_t	peer_wake;

	struct scm_stat		scm_stat;

#if IS_ENABLED(CONFIG_AF_UNIX_OOB)

	struct sk_buff		*oob_skb;

#endif

};



static inline struct unix_sock *unix_sk(const struct sock *sk)

net/unix/Kconfig

+5 −0
Original line number Diff line number Diff line
@@ -25,6 +25,11 @@ config UNIX_SCM 
	depends on UNIX

	default y



config	AF_UNIX_OOB

	bool

	depends on UNIX

	default y



config UNIX_DIAG

	tristate "UNIX: socket monitoring interface"

	depends on UNIX

net/unix/af_unix.c

+151 −2
Original line number Diff line number Diff line
@@ -503,6 +503,12 @@ static void unix_sock_destructor(struct sock *sk) 


	skb_queue_purge(&sk->sk_receive_queue);



#if IS_ENABLED(CONFIG_AF_UNIX_OOB)

	if (u->oob_skb) {

		kfree_skb(u->oob_skb);

		u->oob_skb = NULL;

	}

#endif

	WARN_ON(refcount_read(&sk->sk_wmem_alloc));

	WARN_ON(!sk_unhashed(sk));

	WARN_ON(sk->sk_socket);
@@ -1889,6 +1895,46 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, 
 */

#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))



#if (IS_ENABLED(CONFIG_AF_UNIX_OOB))

static int queue_oob(struct socket *sock, struct msghdr *msg, struct sock *other)

{

	struct unix_sock *ousk = unix_sk(other);

	struct sk_buff *skb;

	int err = 0;



	skb = sock_alloc_send_skb(sock->sk, 1, msg->msg_flags & MSG_DONTWAIT, &err);



	if (!skb)

		return err;



	skb_put(skb, 1);

	skb->len = 1;

	err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, 1);



	if (err) {

		kfree_skb(skb);

		return err;

	}



	unix_state_lock(other);

	maybe_add_creds(skb, sock, other);

	skb_get(skb);



	if (ousk->oob_skb)

		kfree_skb(ousk->oob_skb);



	ousk->oob_skb = skb;



	scm_stat_add(other, skb);

	skb_queue_tail(&other->sk_receive_queue, skb);

	sk_send_sigurg(other);

	unix_state_unlock(other);

	other->sk_data_ready(other);



	return err;

}

#endif



static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,

			       size_t len)

{
@@ -1907,8 +1953,14 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, 
		return err;



	err = -EOPNOTSUPP;

	if (msg->msg_flags&MSG_OOB)

	if (msg->msg_flags & MSG_OOB) {

#if (IS_ENABLED(CONFIG_AF_UNIX_OOB))

		if (len)

			len--;

		else

#endif

			goto out_err;

	}



	if (msg->msg_namelen) {

		err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
@@ -1973,6 +2025,15 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, 
		sent += size;

	}



#if (IS_ENABLED(CONFIG_AF_UNIX_OOB))

	if (msg->msg_flags & MSG_OOB) {

		err = queue_oob(sock, msg, other);

		if (err)

			goto out_err;

		sent++;

	}

#endif



	scm_destroy(&scm);



	return sent;
@@ -2358,6 +2419,59 @@ struct unix_stream_read_state { 
	unsigned int splice_flags;

};



#if IS_ENABLED(CONFIG_AF_UNIX_OOB)

static int unix_stream_recv_urg(struct unix_stream_read_state *state)

{

	struct socket *sock = state->socket;

	struct sock *sk = sock->sk;

	struct unix_sock *u = unix_sk(sk);

	int chunk = 1;



	if (sock_flag(sk, SOCK_URGINLINE) || !u->oob_skb)

		return -EINVAL;



	chunk = state->recv_actor(u->oob_skb, 0, chunk, state);

	if (chunk < 0)

		return -EFAULT;



	if (!(state->flags & MSG_PEEK)) {

		UNIXCB(u->oob_skb).consumed += 1;

		kfree_skb(u->oob_skb);

		u->oob_skb = NULL;

	}

	state->msg->msg_flags |= MSG_OOB;

	return 1;

}



static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,

				  int flags, int copied)

{

	struct unix_sock *u = unix_sk(sk);



	if (!unix_skb_len(skb) && !(flags & MSG_PEEK)) {

		skb_unlink(skb, &sk->sk_receive_queue);

		consume_skb(skb);

		skb = NULL;

	} else {

		if (skb == u->oob_skb) {

			if (copied) {

				skb = NULL;

			} else if (sock_flag(sk, SOCK_URGINLINE)) {

				if (!(flags & MSG_PEEK)) {

					u->oob_skb = NULL;

					consume_skb(skb);

				}

			} else if (!(flags & MSG_PEEK)) {

				skb_unlink(skb, &sk->sk_receive_queue);

				consume_skb(skb);

				skb = skb_peek(&sk->sk_receive_queue);

			}

		}

	}

	return skb;

}

#endif



static int unix_stream_read_generic(struct unix_stream_read_state *state,

				    bool freezable)

{
@@ -2383,6 +2497,15 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state, 


	if (unlikely(flags & MSG_OOB)) {

		err = -EOPNOTSUPP;

#if IS_ENABLED(CONFIG_AF_UNIX_OOB)

		mutex_lock(&u->iolock);

		unix_state_lock(sk);



		err = unix_stream_recv_urg(state);



		unix_state_unlock(sk);

		mutex_unlock(&u->iolock);

#endif

		goto out;

	}
@@ -2411,6 +2534,18 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state, 
		}

		last = skb = skb_peek(&sk->sk_receive_queue);

		last_len = last ? last->len : 0;



#if IS_ENABLED(CONFIG_AF_UNIX_OOB)

		if (skb) {

			skb = manage_oob(skb, sk, flags, copied);

			if (!skb) {

				unix_state_unlock(sk);

				if (copied)

					break;

				goto redo;

			}

		}

#endif

again:

		if (skb == NULL) {

			if (copied >= target)
@@ -2746,6 +2881,20 @@ static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) 
	case SIOCUNIXFILE:

		err = unix_open_file(sk);

		break;

#if IS_ENABLED(CONFIG_AF_UNIX_OOB)

	case SIOCATMARK:

		{

			struct sk_buff *skb;

			struct unix_sock *u = unix_sk(sk);

			int answ = 0;



			skb = skb_peek(&sk->sk_receive_queue);

			if (skb && skb == u->oob_skb)

				answ = 1;

			err = put_user(answ, (int __user *)arg);

		}

		break;

#endif

	default:

		err = -ENOIOCTLCMD;

		break;

tools/testing/selftests/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ TARGETS += mount_setattr 
TARGETS += mqueue

TARGETS += nci

TARGETS += net

TARGETS += net/af_unix

TARGETS += net/forwarding

TARGETS += net/mptcp

TARGETS += netfilter

tools/testing/selftests/net/af_unix/Makefile

0 → 100644
+5 −0
Original line number Diff line number Diff line 
##TEST_GEN_FILES := test_unix_oob

TEST_PROGS := test_unix_oob

include ../../lib.mk



all: $(TEST_PROGS)