linux/include/net/af_unix.h
Kuniyuki Iwashima df30285b36 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>
2025-07-08 18:05:25 -07:00

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1.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_NET_AFUNIX_H
#define __LINUX_NET_AFUNIX_H
#include <linux/atomic.h>
#include <linux/mutex.h>
#include <linux/net.h>
#include <linux/path.h>
#include <linux/refcount.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <net/sock.h>
#include <uapi/linux/un.h>
#if IS_ENABLED(CONFIG_UNIX)
struct unix_sock *unix_get_socket(struct file *filp);
#else
static inline struct unix_sock *unix_get_socket(struct file *filp)
{
return NULL;
}
#endif
struct unix_address {
refcount_t refcnt;
int len;
struct sockaddr_un name[];
};
struct scm_stat {
atomic_t nr_fds;
unsigned long nr_unix_fds;
};
/* The AF_UNIX socket */
struct unix_sock {
/* WARNING: sk has to be the first member */
struct sock sk;
struct unix_address *addr;
struct path path;
struct mutex iolock, bindlock;
struct sock *peer;
struct sock *listener;
struct unix_vertex *vertex;
spinlock_t lock;
struct socket_wq peer_wq;
#define peer_wait peer_wq.wait
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
};
#define unix_sk(ptr) container_of_const(ptr, struct unix_sock, sk)
#define unix_peer(sk) (unix_sk(sk)->peer)
#define unix_state_lock(s) spin_lock(&unix_sk(s)->lock)
#define unix_state_unlock(s) spin_unlock(&unix_sk(s)->lock)
#endif