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mirror of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2025-09-04 20:19:47 +08:00

af_unix: Introduce SO_INQ.

We have an application that uses almost the same code for TCP and
AF_UNIX (SOCK_STREAM).

TCP can use TCP_INQ, but AF_UNIX doesn't have it and requires an
extra syscall, ioctl(SIOCINQ) or getsockopt(SO_MEMINFO) as an
alternative.

Let's introduce the generic version of TCP_INQ.

If SO_INQ is enabled, recvmsg() will put a cmsg of SCM_INQ that
contains the exact value of ioctl(SIOCINQ).  The cmsg is also
included when msg->msg_get_inq is non-zero to make sockets
io_uring-friendly.

Note that SOCK_CUSTOM_SOCKOPT is flagged only for SOCK_STREAM to
override setsockopt() for SOL_SOCKET.

By having the flag in struct unix_sock, instead of struct sock, we
can later add SO_INQ support for TCP and reuse tcp_sk(sk)->recvmsg_inq.

Note also that supporting custom getsockopt() for SOL_SOCKET will need
preparation for other SOCK_CUSTOM_SOCKOPT users (UDP, vsock, MPTCP).

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250702223606.1054680-7-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Kuniyuki Iwashima 2025-07-02 22:35:18 +00:00 committed by Jakub Kicinski
parent 8b77338eb2
commit df30285b36
7 changed files with 76 additions and 2 deletions

View File

@ -152,6 +152,9 @@
#define SO_PASSRIGHTS 83
#define SO_INQ 84
#define SCM_INQ SO_INQ
#if !defined(__KERNEL__)
#if __BITS_PER_LONG == 64

View File

@ -163,6 +163,9 @@
#define SO_PASSRIGHTS 83
#define SO_INQ 84
#define SCM_INQ SO_INQ
#if !defined(__KERNEL__)
#if __BITS_PER_LONG == 64

View File

@ -144,6 +144,9 @@
#define SO_PASSRIGHTS 0x4051
#define SO_INQ 0x4052
#define SCM_INQ SO_INQ
#if !defined(__KERNEL__)
#if __BITS_PER_LONG == 64

View File

@ -145,6 +145,9 @@
#define SO_PASSRIGHTS 0x005c
#define SO_INQ 0x005d
#define SCM_INQ SO_INQ
#if !defined(__KERNEL__)

View File

@ -48,6 +48,7 @@ struct unix_sock {
wait_queue_entry_t peer_wake;
struct scm_stat scm_stat;
int inq_len;
bool recvmsg_inq;
#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
struct sk_buff *oob_skb;
#endif

View File

@ -147,6 +147,9 @@
#define SO_PASSRIGHTS 83
#define SO_INQ 84
#define SCM_INQ SO_INQ
#if !defined(__KERNEL__)
#if __BITS_PER_LONG == 64 || (defined(__x86_64__) && defined(__ILP32__))

View File

@ -934,6 +934,52 @@ static void unix_show_fdinfo(struct seq_file *m, struct socket *sock)
#define unix_show_fdinfo NULL
#endif
static bool unix_custom_sockopt(int optname)
{
switch (optname) {
case SO_INQ:
return true;
default:
return false;
}
}
static int unix_setsockopt(struct socket *sock, int level, int optname,
sockptr_t optval, unsigned int optlen)
{
struct unix_sock *u = unix_sk(sock->sk);
struct sock *sk = sock->sk;
int val;
if (level != SOL_SOCKET)
return -EOPNOTSUPP;
if (!unix_custom_sockopt(optname))
return sock_setsockopt(sock, level, optname, optval, optlen);
if (optlen != sizeof(int))
return -EINVAL;
if (copy_from_sockptr(&val, optval, sizeof(val)))
return -EFAULT;
switch (optname) {
case SO_INQ:
if (sk->sk_type != SOCK_STREAM)
return -EINVAL;
if (val > 1 || val < 0)
return -EINVAL;
WRITE_ONCE(u->recvmsg_inq, val);
break;
default:
return -ENOPROTOOPT;
}
return 0;
}
static const struct proto_ops unix_stream_ops = {
.family = PF_UNIX,
.owner = THIS_MODULE,
@ -950,6 +996,7 @@ static const struct proto_ops unix_stream_ops = {
#endif
.listen = unix_listen,
.shutdown = unix_shutdown,
.setsockopt = unix_setsockopt,
.sendmsg = unix_stream_sendmsg,
.recvmsg = unix_stream_recvmsg,
.read_skb = unix_stream_read_skb,
@ -1116,6 +1163,7 @@ static int unix_create(struct net *net, struct socket *sock, int protocol,
switch (sock->type) {
case SOCK_STREAM:
set_bit(SOCK_CUSTOM_SOCKOPT, &sock->flags);
sock->ops = &unix_stream_ops;
break;
/*
@ -1847,6 +1895,9 @@ static int unix_accept(struct socket *sock, struct socket *newsock,
skb_free_datagram(sk, skb);
wake_up_interruptible(&unix_sk(sk)->peer_wait);
if (tsk->sk_type == SOCK_STREAM)
set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags);
/* attach accepted sock to socket */
unix_state_lock(tsk);
unix_update_edges(unix_sk(tsk));
@ -3034,10 +3085,17 @@ unlock:
} while (size);
mutex_unlock(&u->iolock);
if (msg)
if (msg) {
scm_recv_unix(sock, msg, &scm, flags);
else
if (READ_ONCE(u->recvmsg_inq) || msg->msg_get_inq) {
msg->msg_inq = READ_ONCE(u->inq_len);
put_cmsg(msg, SOL_SOCKET, SCM_INQ,
sizeof(msg->msg_inq), &msg->msg_inq);
}
} else {
scm_destroy(&scm);
}
out:
return copied ? : err;
}