include/net/sock.h

Source file repositories/reference/linux-study-clean/include/net/sock.h

File Facts

System
Linux kernel
Corpus path
include/net/sock.h
Extension
.h
Size
91421 bytes
Lines
3185
Domain
Networking Core
Bucket
Sockets, Protocols, Packet Path, And Network Policy
Inferred role
Networking Core: operation-table or driver-model contract
Status
pattern implementation candidate

Why This File Exists

Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.

Dependency Surface

Detected Declarations

Annotated Snippet

* Functions to fill in entries in struct proto_ops when a protocol
 * does not implement a particular function.
 */
int sock_no_bind(struct socket *sock, struct sockaddr_unsized *saddr, int len);
int sock_no_connect(struct socket *sock, struct sockaddr_unsized *saddr, int len, int flags);
int sock_no_socketpair(struct socket *, struct socket *);
int sock_no_accept(struct socket *, struct socket *, struct proto_accept_arg *);
int sock_no_getname(struct socket *, struct sockaddr *, int);
int sock_no_ioctl(struct socket *, unsigned int, unsigned long);
int sock_no_listen(struct socket *, int);
int sock_no_shutdown(struct socket *, int);
int sock_no_sendmsg(struct socket *, struct msghdr *, size_t);
int sock_no_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t len);
int sock_no_recvmsg(struct socket *, struct msghdr *, size_t, int);
int sock_no_mmap(struct file *file, struct socket *sock,
		 struct vm_area_struct *vma);

/*
 * Functions to fill in entries in struct proto_ops when a protocol
 * uses the inet style.
 */
int sock_common_getsockopt(struct socket *sock, int level, int optname,
				  char __user *optval, int __user *optlen);
int sock_common_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
			int flags);
int sock_common_setsockopt(struct socket *sock, int level, int optname,
			   sockptr_t optval, unsigned int optlen);

void sk_common_release(struct sock *sk);

/*
 *	Default socket callbacks and setup code
 */

/* Initialise core socket variables using an explicit uid. */
void sock_init_data_uid(struct socket *sock, struct sock *sk, kuid_t uid);

/* Initialise core socket variables.
 * Assumes struct socket *sock is embedded in a struct socket_alloc.
 */
void sock_init_data(struct socket *sock, struct sock *sk);

/*
 * Socket reference counting postulates.
 *
 * * Each user of socket SHOULD hold a reference count.
 * * Each access point to socket (an hash table bucket, reference from a list,
 *   running timer, skb in flight MUST hold a reference count.
 * * When reference count hits 0, it means it will never increase back.
 * * When reference count hits 0, it means that no references from
 *   outside exist to this socket and current process on current CPU
 *   is last user and may/should destroy this socket.
 * * sk_free is called from any context: process, BH, IRQ. When
 *   it is called, socket has no references from outside -> sk_free
 *   may release descendant resources allocated by the socket, but
 *   to the time when it is called, socket is NOT referenced by any
 *   hash tables, lists etc.
 * * Packets, delivered from outside (from network or from another process)
 *   and enqueued on receive/error queues SHOULD NOT grab reference count,
 *   when they sit in queue. Otherwise, packets will leak to hole, when
 *   socket is looked up by one cpu and unhasing is made by another CPU.
 *   It is true for udp/raw, netlink (leak to receive and error queues), tcp
 *   (leak to backlog). Packet socket does all the processing inside
 *   BR_NETPROTO_LOCK, so that it has not this race condition. UNIX sockets
 *   use separate SMP lock, so that they are prone too.
 */

/* Ungrab socket and destroy it, if it was the last reference. */
static inline void sock_put(struct sock *sk)
{
	if (refcount_dec_and_test(&sk->sk_refcnt))
		sk_free(sk);
}
/* Generic version of sock_put(), dealing with all sockets
 * (TCP_TIMEWAIT, TCP_NEW_SYN_RECV, ESTABLISHED...)
 */
void sock_gen_put(struct sock *sk);

int __sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested,
		     unsigned int trim_cap, bool refcounted);
static inline int sk_receive_skb(struct sock *sk, struct sk_buff *skb,
				 const int nested)
{
	return __sk_receive_skb(sk, skb, nested, 1, true);
}

static inline void sk_tx_queue_set(struct sock *sk, int tx_queue)
{
	/* sk_tx_queue_mapping accept only upto a 16-bit value */
	if (WARN_ON_ONCE((unsigned short)tx_queue >= USHRT_MAX))

Annotation

Implementation Notes