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authorRao Shoaib <rao.shoaib@oracle.com>2021-08-01 10:57:07 +0300
committerDavid S. Miller <davem@davemloft.net>2021-08-04 11:55:52 +0300
commit314001f0bf927015e459c9d387d62a231fe93af3 (patch)
tree3f5a7d31a347e495833cffdbd638852111bbb78c /net/unix
parent7e89350c901923c48370ae7b922223c6c5a2b7fd (diff)
downloadlinux-314001f0bf927015e459c9d387d62a231fe93af3.tar.xz
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: Rao Shoaib <rao.shoaib@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/unix')
-rw-r--r--net/unix/Kconfig5
-rw-r--r--net/unix/af_unix.c153
2 files changed, 156 insertions, 2 deletions
diff --git a/net/unix/Kconfig b/net/unix/Kconfig
index b6c4282899ec..b7f811216820 100644
--- a/net/unix/Kconfig
+++ b/net/unix/Kconfig
@@ -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
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 256c4e31132e..ec02e70a549b 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -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 @@ out:
*/
#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)
- goto out_err;
+ 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 @@ redo:
}
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;