blob: fd98760876513ffb4020a37a1ec43f1704085c80 [file] [log] [blame]
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
* Definitions for the AF_INET socket handler.
* Version: @(#)sock.h 1.0.4 05/13/93
* Authors: Ross Biro
* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
* Corey Minyard <wf-rch!>
* Florian La Roche <>
* Fixes:
* Alan Cox : Volatiles in skbuff pointers. See
* skbuff comments. May be overdone,
* better to prove they can be removed
* than the reverse.
* Alan Cox : Added a zapped field for tcp to note
* a socket is reset and must stay shut up
* Alan Cox : New fields for options
* Pauline Middelink : identd support
* Alan Cox : Eliminate low level recv/recvfrom
* David S. Miller : New socket lookup architecture.
* Steve Whitehouse: Default routines for sock_ops
* Arnaldo C. Melo : removed net_pinfo, tp_pinfo and made
* protinfo be just a void pointer, as the
* protocol specific parts were moved to
* respective headers and ipv4/v6, etc now
* use private slabcaches for its socks
* Pedro Hortas : New flags field for socket options
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
#ifndef _SOCK_H
#define _SOCK_H
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/timer.h>
#include <linux/cache.h>
#include <linux/module.h>
#include <linux/lockdep.h>
#include <linux/netdevice.h>
#include <linux/pcounter.h>
#include <linux/skbuff.h> /* struct sk_buff */
#include <linux/mm.h>
#include <linux/security.h>
#include <linux/filter.h>
#include <asm/atomic.h>
#include <net/dst.h>
#include <net/checksum.h>
* This structure really needs to be cleaned up.
* Most of it is for TCP, and not used by any of
* the other protocols.
/* Define this to get the SOCK_DBG debugging facility. */
#define SOCK_DEBUG(sk, msg...) do { if ((sk) && sock_flag((sk), SOCK_DBG)) \
printk(KERN_DEBUG msg); } while (0)
#define SOCK_DEBUG(sk, msg...) do { } while (0)
/* This is the per-socket lock. The spinlock provides a synchronization
* between user contexts and software interrupt processing, whereas the
* mini-semaphore synchronizes multiple users amongst themselves.
typedef struct {
spinlock_t slock;
int owned;
wait_queue_head_t wq;
* We express the mutex-alike socket_lock semantics
* to the lock validator by explicitly managing
* the slock as a lock variant (in addition to
* the slock itself):
struct lockdep_map dep_map;
} socket_lock_t;
struct sock;
struct proto;
struct net;
* struct sock_common - minimal network layer representation of sockets
* @skc_family: network address family
* @skc_state: Connection state
* @skc_reuse: %SO_REUSEADDR setting
* @skc_bound_dev_if: bound device index if != 0
* @skc_node: main hash linkage for various protocol lookup tables
* @skc_bind_node: bind hash linkage for various protocol lookup tables
* @skc_refcnt: reference count
* @skc_hash: hash value used with various protocol lookup tables
* @skc_prot: protocol handlers inside a network family
* @skc_net: reference to the network namespace of this socket
* This is the minimal network layer representation of sockets, the header
* for struct sock and struct inet_timewait_sock.
struct sock_common {
unsigned short skc_family;
volatile unsigned char skc_state;
unsigned char skc_reuse;
int skc_bound_dev_if;
struct hlist_node skc_node;
struct hlist_node skc_bind_node;
atomic_t skc_refcnt;
unsigned int skc_hash;
struct proto *skc_prot;
struct net *skc_net;
* struct sock - network layer representation of sockets
* @__sk_common: shared layout with inet_timewait_sock
* @sk_shutdown: mask of %SEND_SHUTDOWN and/or %RCV_SHUTDOWN
* @sk_userlocks: %SO_SNDBUF and %SO_RCVBUF settings
* @sk_lock: synchronizer
* @sk_rcvbuf: size of receive buffer in bytes
* @sk_sleep: sock wait queue
* @sk_dst_cache: destination cache
* @sk_dst_lock: destination cache lock
* @sk_policy: flow policy
* @sk_rmem_alloc: receive queue bytes committed
* @sk_receive_queue: incoming packets
* @sk_wmem_alloc: transmit queue bytes committed
* @sk_write_queue: Packet sending queue
* @sk_async_wait_queue: DMA copied packets
* @sk_omem_alloc: "o" is "option" or "other"
* @sk_wmem_queued: persistent queue size
* @sk_forward_alloc: space allocated forward
* @sk_allocation: allocation mode
* @sk_sndbuf: size of send buffer in bytes
* @sk_flags: %SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE,
* %SO_OOBINLINE settings
* @sk_no_check: %SO_NO_CHECK setting, wether or not checkup packets
* @sk_route_caps: route capabilities (e.g. %NETIF_F_TSO)
* @sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
* @sk_lingertime: %SO_LINGER l_linger setting
* @sk_backlog: always used with the per-socket spinlock held
* @sk_callback_lock: used with the callbacks in the end of this struct
* @sk_error_queue: rarely used
* @sk_prot_creator: sk_prot of original sock creator (see ipv6_setsockopt,
* IPV6_ADDRFORM for instance)
* @sk_err: last error
* @sk_err_soft: errors that don't cause failure but are the cause of a
* persistent failure not just 'timed out'
* @sk_drops: raw drops counter
* @sk_ack_backlog: current listen backlog
* @sk_max_ack_backlog: listen backlog set in listen()
* @sk_priority: %SO_PRIORITY setting
* @sk_type: socket type (%SOCK_STREAM, etc)
* @sk_protocol: which protocol this socket belongs in this network family
* @sk_peercred: %SO_PEERCRED setting
* @sk_rcvlowat: %SO_RCVLOWAT setting
* @sk_rcvtimeo: %SO_RCVTIMEO setting
* @sk_sndtimeo: %SO_SNDTIMEO setting
* @sk_filter: socket filtering instructions
* @sk_protinfo: private area, net family specific, when not using slab
* @sk_timer: sock cleanup timer
* @sk_stamp: time stamp of last packet received
* @sk_socket: Identd and reporting IO signals
* @sk_user_data: RPC layer private data
* @sk_sndmsg_page: cached page for sendmsg
* @sk_sndmsg_off: cached offset for sendmsg
* @sk_send_head: front of stuff to transmit
* @sk_security: used by security modules
* @sk_mark: generic packet mark
* @sk_write_pending: a write to stream socket waits to start
* @sk_state_change: callback to indicate change in the state of the sock
* @sk_data_ready: callback to indicate there is data to be processed
* @sk_write_space: callback to indicate there is bf sending space available
* @sk_error_report: callback to indicate errors (e.g. %MSG_ERRQUEUE)
* @sk_backlog_rcv: callback to process the backlog
* @sk_destruct: called at sock freeing time, i.e. when all refcnt == 0
struct sock {
* Now struct inet_timewait_sock also uses sock_common, so please just
* don't add nothing before this first member (__sk_common) --acme
struct sock_common __sk_common;
#define sk_family __sk_common.skc_family
#define sk_state __sk_common.skc_state
#define sk_reuse __sk_common.skc_reuse
#define sk_bound_dev_if __sk_common.skc_bound_dev_if
#define sk_node __sk_common.skc_node
#define sk_bind_node __sk_common.skc_bind_node
#define sk_refcnt __sk_common.skc_refcnt
#define sk_hash __sk_common.skc_hash
#define sk_prot __sk_common.skc_prot
#define sk_net __sk_common.skc_net
unsigned char sk_shutdown : 2,
sk_no_check : 2,
sk_userlocks : 4;
unsigned char sk_protocol;
unsigned short sk_type;
int sk_rcvbuf;
socket_lock_t sk_lock;
* The backlog queue is special, it is always used with
* the per-socket spinlock held and requires low latency
* access. Therefore we special case it's implementation.
struct {
struct sk_buff *head;
struct sk_buff *tail;
} sk_backlog;
wait_queue_head_t *sk_sleep;
struct dst_entry *sk_dst_cache;
struct xfrm_policy *sk_policy[2];
rwlock_t sk_dst_lock;
atomic_t sk_rmem_alloc;
atomic_t sk_wmem_alloc;
atomic_t sk_omem_alloc;
int sk_sndbuf;
struct sk_buff_head sk_receive_queue;
struct sk_buff_head sk_write_queue;
struct sk_buff_head sk_async_wait_queue;
int sk_wmem_queued;
int sk_forward_alloc;
gfp_t sk_allocation;
int sk_route_caps;
int sk_gso_type;
int sk_rcvlowat;
unsigned long sk_flags;
unsigned long sk_lingertime;
struct sk_buff_head sk_error_queue;
struct proto *sk_prot_creator;
rwlock_t sk_callback_lock;
int sk_err,
atomic_t sk_drops;
unsigned short sk_ack_backlog;
unsigned short sk_max_ack_backlog;
__u32 sk_priority;
struct ucred sk_peercred;
long sk_rcvtimeo;
long sk_sndtimeo;
struct sk_filter *sk_filter;
void *sk_protinfo;
struct timer_list sk_timer;
ktime_t sk_stamp;
struct socket *sk_socket;
void *sk_user_data;
struct page *sk_sndmsg_page;
struct sk_buff *sk_send_head;
__u32 sk_sndmsg_off;
int sk_write_pending;
void *sk_security;
__u32 sk_mark;
/* XXX 4 bytes hole on 64 bit */
void (*sk_state_change)(struct sock *sk);
void (*sk_data_ready)(struct sock *sk, int bytes);
void (*sk_write_space)(struct sock *sk);
void (*sk_error_report)(struct sock *sk);
int (*sk_backlog_rcv)(struct sock *sk,
struct sk_buff *skb);
void (*sk_destruct)(struct sock *sk);
* Hashed lists helper routines
static inline struct sock *__sk_head(const struct hlist_head *head)
return hlist_entry(head->first, struct sock, sk_node);
static inline struct sock *sk_head(const struct hlist_head *head)
return hlist_empty(head) ? NULL : __sk_head(head);
static inline struct sock *sk_next(const struct sock *sk)
return sk-> ?
hlist_entry(sk->, struct sock, sk_node) : NULL;
static inline int sk_unhashed(const struct sock *sk)
return hlist_unhashed(&sk->sk_node);
static inline int sk_hashed(const struct sock *sk)
return !sk_unhashed(sk);
static __inline__ void sk_node_init(struct hlist_node *node)
node->pprev = NULL;
static __inline__ void __sk_del_node(struct sock *sk)
static __inline__ int __sk_del_node_init(struct sock *sk)
if (sk_hashed(sk)) {
return 1;
return 0;
/* Grab socket reference count. This operation is valid only
when sk is ALREADY grabbed f.e. it is found in hash table
or a list and the lookup is made under lock preventing hash table
static inline void sock_hold(struct sock *sk)
/* Ungrab socket in the context, which assumes that socket refcnt
cannot hit zero, f.e. it is true in context of any socketcall.
static inline void __sock_put(struct sock *sk)
static __inline__ int sk_del_node_init(struct sock *sk)
int rc = __sk_del_node_init(sk);
if (rc) {
/* paranoid for a while -acme */
WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
return rc;
static __inline__ void __sk_add_node(struct sock *sk, struct hlist_head *list)
hlist_add_head(&sk->sk_node, list);
static __inline__ void sk_add_node(struct sock *sk, struct hlist_head *list)
__sk_add_node(sk, list);
static __inline__ void __sk_del_bind_node(struct sock *sk)
static __inline__ void sk_add_bind_node(struct sock *sk,
struct hlist_head *list)
hlist_add_head(&sk->sk_bind_node, list);
#define sk_for_each(__sk, node, list) \
hlist_for_each_entry(__sk, node, list, sk_node)
#define sk_for_each_from(__sk, node) \
if (__sk && ({ node = &(__sk)->sk_node; 1; })) \
hlist_for_each_entry_from(__sk, node, sk_node)
#define sk_for_each_continue(__sk, node) \
if (__sk && ({ node = &(__sk)->sk_node; 1; })) \
hlist_for_each_entry_continue(__sk, node, sk_node)
#define sk_for_each_safe(__sk, node, tmp, list) \
hlist_for_each_entry_safe(__sk, node, tmp, list, sk_node)
#define sk_for_each_bound(__sk, node, list) \
hlist_for_each_entry(__sk, node, list, sk_bind_node)
/* Sock flags */
enum sock_flags {
SOCK_USE_WRITE_QUEUE, /* whether to call sk->sk_write_space in sock_wfree */
SOCK_DBG, /* %SO_DEBUG setting */
SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
SOCK_QUEUE_SHRUNK, /* write queue has been shrunk recently */
static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
nsk->sk_flags = osk->sk_flags;
static inline void sock_set_flag(struct sock *sk, enum sock_flags flag)
__set_bit(flag, &sk->sk_flags);
static inline void sock_reset_flag(struct sock *sk, enum sock_flags flag)
__clear_bit(flag, &sk->sk_flags);
static inline int sock_flag(struct sock *sk, enum sock_flags flag)
return test_bit(flag, &sk->sk_flags);
static inline void sk_acceptq_removed(struct sock *sk)
static inline void sk_acceptq_added(struct sock *sk)
static inline int sk_acceptq_is_full(struct sock *sk)
return sk->sk_ack_backlog > sk->sk_max_ack_backlog;
* Compute minimal free write space needed to queue new packets.
static inline int sk_stream_min_wspace(struct sock *sk)
return sk->sk_wmem_queued >> 1;
static inline int sk_stream_wspace(struct sock *sk)
return sk->sk_sndbuf - sk->sk_wmem_queued;
extern void sk_stream_write_space(struct sock *sk);
static inline int sk_stream_memory_free(struct sock *sk)
return sk->sk_wmem_queued < sk->sk_sndbuf;
/* The per-socket spinlock must be held here. */
static inline void sk_add_backlog(struct sock *sk, struct sk_buff *skb)
if (!sk->sk_backlog.tail) {
sk->sk_backlog.head = sk->sk_backlog.tail = skb;
} else {
sk->sk_backlog.tail->next = skb;
sk->sk_backlog.tail = skb;
skb->next = NULL;
#define sk_wait_event(__sk, __timeo, __condition) \
({ int __rc; \
release_sock(__sk); \
__rc = __condition; \
if (!__rc) { \
*(__timeo) = schedule_timeout(*(__timeo)); \
} \
lock_sock(__sk); \
__rc = __condition; \
__rc; \
extern int sk_stream_wait_connect(struct sock *sk, long *timeo_p);
extern int sk_stream_wait_memory(struct sock *sk, long *timeo_p);
extern void sk_stream_wait_close(struct sock *sk, long timeo_p);
extern int sk_stream_error(struct sock *sk, int flags, int err);
extern void sk_stream_kill_queues(struct sock *sk);
extern int sk_wait_data(struct sock *sk, long *timeo);
struct request_sock_ops;
struct timewait_sock_ops;
struct inet_hashinfo;
/* Networking protocol blocks we attach to sockets.
* socket layer -> transport layer interface
* transport -> network interface is defined by struct inet_proto
struct proto {
void (*close)(struct sock *sk,
long timeout);
int (*connect)(struct sock *sk,
struct sockaddr *uaddr,
int addr_len);
int (*disconnect)(struct sock *sk, int flags);
struct sock * (*accept) (struct sock *sk, int flags, int *err);
int (*ioctl)(struct sock *sk, int cmd,
unsigned long arg);
int (*init)(struct sock *sk);
int (*destroy)(struct sock *sk);
void (*shutdown)(struct sock *sk, int how);
int (*setsockopt)(struct sock *sk, int level,
int optname, char __user *optval,
int optlen);
int (*getsockopt)(struct sock *sk, int level,
int optname, char __user *optval,
int __user *option);
int (*compat_setsockopt)(struct sock *sk,
int level,
int optname, char __user *optval,
int optlen);
int (*compat_getsockopt)(struct sock *sk,
int level,
int optname, char __user *optval,
int __user *option);
int (*sendmsg)(struct kiocb *iocb, struct sock *sk,
struct msghdr *msg, size_t len);
int (*recvmsg)(struct kiocb *iocb, struct sock *sk,
struct msghdr *msg,
size_t len, int noblock, int flags,
int *addr_len);
int (*sendpage)(struct sock *sk, struct page *page,
int offset, size_t size, int flags);
int (*bind)(struct sock *sk,
struct sockaddr *uaddr, int addr_len);
int (*backlog_rcv) (struct sock *sk,
struct sk_buff *skb);
/* Keeping track of sk's, looking them up, and port selection methods. */
void (*hash)(struct sock *sk);
void (*unhash)(struct sock *sk);
int (*get_port)(struct sock *sk, unsigned short snum);
/* Keeping track of sockets in use */
struct pcounter inuse;
/* Memory pressure */
void (*enter_memory_pressure)(void);
atomic_t *memory_allocated; /* Current allocated memory. */
atomic_t *sockets_allocated; /* Current number of sockets. */
* Pressure flag: try to collapse.
* Technical note: it is used by multiple contexts non atomically.
* All the __sk_mem_schedule() is of this nature: accounting
* is strict, actions are advisory and have some latency.
int *memory_pressure;
int *sysctl_mem;
int *sysctl_wmem;
int *sysctl_rmem;
int max_header;
struct kmem_cache *slab;
unsigned int obj_size;
atomic_t *orphan_count;
struct request_sock_ops *rsk_prot;
struct timewait_sock_ops *twsk_prot;
struct inet_hashinfo *hashinfo;
struct module *owner;
char name[32];
struct list_head node;
atomic_t socks;
extern int proto_register(struct proto *prot, int alloc_slab);
extern void proto_unregister(struct proto *prot);
static inline void sk_refcnt_debug_inc(struct sock *sk)
static inline void sk_refcnt_debug_dec(struct sock *sk)
printk(KERN_DEBUG "%s socket %p released, %d are still alive\n",
sk->sk_prot->name, sk, atomic_read(&sk->sk_prot->socks));
static inline void sk_refcnt_debug_release(const struct sock *sk)
if (atomic_read(&sk->sk_refcnt) != 1)
printk(KERN_DEBUG "Destruction of the %s socket %p delayed, refcnt=%d\n",
sk->sk_prot->name, sk, atomic_read(&sk->sk_refcnt));
#define sk_refcnt_debug_inc(sk) do { } while (0)
#define sk_refcnt_debug_dec(sk) do { } while (0)
#define sk_refcnt_debug_release(sk) do { } while (0)
#endif /* SOCK_REFCNT_DEBUG */
/* Called with local bh disabled */
static inline void sock_prot_inuse_add(struct proto *prot, int inc)
pcounter_add(&prot->inuse, inc);
static inline int sock_prot_inuse_init(struct proto *proto)
return pcounter_alloc(&proto->inuse);
static inline int sock_prot_inuse_get(struct proto *proto)
return pcounter_getval(&proto->inuse);
static inline void sock_prot_inuse_free(struct proto *proto)
static void inline sock_prot_inuse_add(struct proto *prot, int inc)
static int inline sock_prot_inuse_init(struct proto *proto)
return 0;
static void inline sock_prot_inuse_free(struct proto *proto)
/* With per-bucket locks this operation is not-atomic, so that
* this version is not worse.
static inline void __sk_prot_rehash(struct sock *sk)
/* About 10 seconds */
/* Sockets 0-1023 can't be bound to unless you are superuser */
#define PROT_SOCK 1024
#define RCV_SHUTDOWN 1
/* sock_iocb: used to kick off async processing of socket ios */
struct sock_iocb {
struct list_head list;
int flags;
int size;
struct socket *sock;
struct sock *sk;
struct scm_cookie *scm;
struct msghdr *msg, async_msg;
struct kiocb *kiocb;
static inline struct sock_iocb *kiocb_to_siocb(struct kiocb *iocb)
return (struct sock_iocb *)iocb->private;
static inline struct kiocb *siocb_to_kiocb(struct sock_iocb *si)
return si->kiocb;
struct socket_alloc {
struct socket socket;
struct inode vfs_inode;
static inline struct socket *SOCKET_I(struct inode *inode)
return &container_of(inode, struct socket_alloc, vfs_inode)->socket;
static inline struct inode *SOCK_INODE(struct socket *socket)
return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
* Functions for memory accounting
extern int __sk_mem_schedule(struct sock *sk, int size, int kind);
extern void __sk_mem_reclaim(struct sock *sk);
#define SK_MEM_SEND 0
#define SK_MEM_RECV 1
static inline int sk_mem_pages(int amt)
return (amt + SK_MEM_QUANTUM - 1) >> SK_MEM_QUANTUM_SHIFT;
static inline int sk_has_account(struct sock *sk)
/* return true if protocol supports memory accounting */
return !!sk->sk_prot->memory_allocated;
static inline int sk_wmem_schedule(struct sock *sk, int size)
if (!sk_has_account(sk))
return 1;
return size <= sk->sk_forward_alloc ||
__sk_mem_schedule(sk, size, SK_MEM_SEND);
static inline int sk_rmem_schedule(struct sock *sk, int size)
if (!sk_has_account(sk))
return 1;
return size <= sk->sk_forward_alloc ||
__sk_mem_schedule(sk, size, SK_MEM_RECV);
static inline void sk_mem_reclaim(struct sock *sk)
if (!sk_has_account(sk))
if (sk->sk_forward_alloc >= SK_MEM_QUANTUM)
static inline void sk_mem_reclaim_partial(struct sock *sk)
if (!sk_has_account(sk))
if (sk->sk_forward_alloc > SK_MEM_QUANTUM)
static inline void sk_mem_charge(struct sock *sk, int size)
if (!sk_has_account(sk))
sk->sk_forward_alloc -= size;
static inline void sk_mem_uncharge(struct sock *sk, int size)
if (!sk_has_account(sk))
sk->sk_forward_alloc += size;
static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
sock_set_flag(sk, SOCK_QUEUE_SHRUNK);
sk->sk_wmem_queued -= skb->truesize;
sk_mem_uncharge(sk, skb->truesize);
/* Used by processes to "lock" a socket state, so that
* interrupts and bottom half handlers won't change it
* from under us. It essentially blocks any incoming
* packets, so that we won't get any new data or any
* packets that change the state of the socket.
* While locked, BH processing will add new packets to
* the backlog queue. This queue is processed by the
* owner of the socket lock right before it is released.
* Since ~2.3.5 it is also exclusive sleep lock serializing
* accesses from user process context.
#define sock_owned_by_user(sk) ((sk)->sk_lock.owned)
* Macro so as to not evaluate some arguments when
* lockdep is not enabled.
* Mark both the sk_lock and the sk_lock.slock as a
* per-address-family lock class.
#define sock_lock_init_class_and_name(sk, sname, skey, name, key) \
do { \
sk->sk_lock.owned = 0; \
init_waitqueue_head(&sk->sk_lock.wq); \
spin_lock_init(&(sk)->sk_lock.slock); \
debug_check_no_locks_freed((void *)&(sk)->sk_lock, \
sizeof((sk)->sk_lock)); \
lockdep_set_class_and_name(&(sk)->sk_lock.slock, \
(skey), (sname)); \
lockdep_init_map(&(sk)->sk_lock.dep_map, (name), (key), 0); \
} while (0)
extern void lock_sock_nested(struct sock *sk, int subclass);
static inline void lock_sock(struct sock *sk)
lock_sock_nested(sk, 0);
extern void release_sock(struct sock *sk);
/* BH context may only use the following locking interface. */
#define bh_lock_sock(__sk) spin_lock(&((__sk)->sk_lock.slock))
#define bh_lock_sock_nested(__sk) \
spin_lock_nested(&((__sk)->sk_lock.slock), \
#define bh_unlock_sock(__sk) spin_unlock(&((__sk)->sk_lock.slock))
extern struct sock *sk_alloc(struct net *net, int family,
gfp_t priority,
struct proto *prot);
extern void sk_free(struct sock *sk);
extern struct sock *sk_clone(const struct sock *sk,
const gfp_t priority);
extern struct sk_buff *sock_wmalloc(struct sock *sk,
unsigned long size, int force,
gfp_t priority);
extern struct sk_buff *sock_rmalloc(struct sock *sk,
unsigned long size, int force,
gfp_t priority);
extern void sock_wfree(struct sk_buff *skb);
extern void sock_rfree(struct sk_buff *skb);
extern int sock_setsockopt(struct socket *sock, int level,
int op, char __user *optval,
int optlen);
extern int sock_getsockopt(struct socket *sock, int level,
int op, char __user *optval,
int __user *optlen);
extern struct sk_buff *sock_alloc_send_skb(struct sock *sk,
unsigned long size,
int noblock,
int *errcode);
extern void *sock_kmalloc(struct sock *sk, int size,
gfp_t priority);
extern void sock_kfree_s(struct sock *sk, void *mem, int size);
extern void sk_send_sigurg(struct sock *sk);
* Functions to fill in entries in struct proto_ops when a protocol
* does not implement a particular function.
extern int sock_no_bind(struct socket *,
struct sockaddr *, int);
extern int sock_no_connect(struct socket *,
struct sockaddr *, int, int);
extern int sock_no_socketpair(struct socket *,
struct socket *);
extern int sock_no_accept(struct socket *,
struct socket *, int);
extern int sock_no_getname(struct socket *,
struct sockaddr *, int *, int);
extern unsigned int sock_no_poll(struct file *, struct socket *,
struct poll_table_struct *);
extern int sock_no_ioctl(struct socket *, unsigned int,
unsigned long);
extern int sock_no_listen(struct socket *, int);
extern int sock_no_shutdown(struct socket *, int);
extern int sock_no_getsockopt(struct socket *, int , int,
char __user *, int __user *);
extern int sock_no_setsockopt(struct socket *, int, int,
char __user *, int);
extern int sock_no_sendmsg(struct kiocb *, struct socket *,
struct msghdr *, size_t);
extern int sock_no_recvmsg(struct kiocb *, struct socket *,
struct msghdr *, size_t, int);
extern int sock_no_mmap(struct file *file,
struct socket *sock,
struct vm_area_struct *vma);
extern ssize_t sock_no_sendpage(struct socket *sock,
struct page *page,
int offset, size_t size,
int flags);
* Functions to fill in entries in struct proto_ops when a protocol
* uses the inet style.
extern int sock_common_getsockopt(struct socket *sock, int level, int optname,
char __user *optval, int __user *optlen);
extern int sock_common_recvmsg(struct kiocb *iocb, struct socket *sock,
struct msghdr *msg, size_t size, int flags);
extern int sock_common_setsockopt(struct socket *sock, int level, int optname,
char __user *optval, int optlen);
extern int compat_sock_common_getsockopt(struct socket *sock, int level,
int optname, char __user *optval, int __user *optlen);
extern int compat_sock_common_setsockopt(struct socket *sock, int level,
int optname, char __user *optval, int optlen);
extern void sk_common_release(struct sock *sk);
* Default socket callbacks and setup code
/* Initialise core socket variables */
extern void sock_init_data(struct socket *sock, struct sock *sk);
* sk_filter - run a packet through a socket filter
* @sk: sock associated with &sk_buff
* @skb: buffer to filter
* @needlock: set to 1 if the sock is not locked by caller.
* Run the filter code and then cut skb->data to correct size returned by
* sk_run_filter. If pkt_len is 0 we toss packet. If skb->len is smaller
* than pkt_len we keep whole skb->data. This is the socket level
* wrapper to sk_run_filter. It returns 0 if the packet should
* be accepted or -EPERM if the packet should be tossed.
static inline int sk_filter(struct sock *sk, struct sk_buff *skb)
int err;
struct sk_filter *filter;
err = security_sock_rcv_skb(sk, skb);
if (err)
return err;
filter = rcu_dereference(sk->sk_filter);
if (filter) {
unsigned int pkt_len = sk_run_filter(skb, filter->insns,
err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM;
return err;
* sk_filter_release: Release a socket filter
* @sk: socket
* @fp: filter to remove
* Remove a filter from a socket and release its resources.
static inline void sk_filter_release(struct sk_filter *fp)
if (atomic_dec_and_test(&fp->refcnt))
static inline void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp)
unsigned int size = sk_filter_len(fp);
atomic_sub(size, &sk->sk_omem_alloc);
static inline void sk_filter_charge(struct sock *sk, struct sk_filter *fp)
atomic_add(sk_filter_len(fp), &sk->sk_omem_alloc);
* 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 (atomic_dec_and_test(&sk->sk_refcnt))
extern int sk_receive_skb(struct sock *sk, struct sk_buff *skb,
const int nested);
/* Detach socket from process context.
* Announce socket dead, detach it from wait queue and inode.
* Note that parent inode held reference count on this struct sock,
* we do not release it in this function, because protocol
* probably wants some additional cleanups or even continuing
* to work with this socket (TCP).
static inline void sock_orphan(struct sock *sk)
sock_set_flag(sk, SOCK_DEAD);
sk->sk_socket = NULL;
sk->sk_sleep = NULL;
static inline void sock_graft(struct sock *sk, struct socket *parent)
sk->sk_sleep = &parent->wait;
parent->sk = sk;
sk->sk_socket = parent;
security_sock_graft(sk, parent);
extern int sock_i_uid(struct sock *sk);
extern unsigned long sock_i_ino(struct sock *sk);
static inline struct dst_entry *
__sk_dst_get(struct sock *sk)
return sk->sk_dst_cache;
static inline struct dst_entry *
sk_dst_get(struct sock *sk)
struct dst_entry *dst;
dst = sk->sk_dst_cache;
if (dst)
return dst;
static inline void
__sk_dst_set(struct sock *sk, struct dst_entry *dst)
struct dst_entry *old_dst;
old_dst = sk->sk_dst_cache;
sk->sk_dst_cache = dst;
static inline void
sk_dst_set(struct sock *sk, struct dst_entry *dst)
__sk_dst_set(sk, dst);
static inline void
__sk_dst_reset(struct sock *sk)
struct dst_entry *old_dst;
old_dst = sk->sk_dst_cache;
sk->sk_dst_cache = NULL;
static inline void
sk_dst_reset(struct sock *sk)
extern struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie);
extern struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie);
static inline int sk_can_gso(const struct sock *sk)
return net_gso_ok(sk->sk_route_caps, sk->sk_gso_type);
extern void sk_setup_caps(struct sock *sk, struct dst_entry *dst);
static inline int skb_copy_to_page(struct sock *sk, char __user *from,
struct sk_buff *skb, struct page *page,
int off, int copy)
if (skb->ip_summed == CHECKSUM_NONE) {
int err = 0;
__wsum csum = csum_and_copy_from_user(from,
page_address(page) + off,
copy, 0, &err);
if (err)
return err;
skb->csum = csum_block_add(skb->csum, csum, skb->len);
} else if (copy_from_user(page_address(page) + off, from, copy))
return -EFAULT;
skb->len += copy;
skb->data_len += copy;
skb->truesize += copy;
sk->sk_wmem_queued += copy;
sk_mem_charge(sk, copy);
return 0;
* Queue a received datagram if it will fit. Stream and sequenced
* protocols can't normally use this as they need to fit buffers in
* and play with them.
* Inlined as it's very short and called for pretty much every
* packet ever received.
static inline void skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
skb->sk = sk;
skb->destructor = sock_wfree;
atomic_add(skb->truesize, &sk->sk_wmem_alloc);
static inline void skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
skb->sk = sk;
skb->destructor = sock_rfree;
atomic_add(skb->truesize, &sk->sk_rmem_alloc);
sk_mem_charge(sk, skb->truesize);
extern void sk_reset_timer(struct sock *sk, struct timer_list* timer,
unsigned long expires);
extern void sk_stop_timer(struct sock *sk, struct timer_list* timer);
extern int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
static inline int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
/* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
number of warnings when compiling with -W --ANK
if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
return -ENOMEM;
skb_set_owner_r(skb, sk);
skb_queue_tail(&sk->sk_error_queue, skb);
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_data_ready(sk, skb->len);
return 0;
* Recover an error report and clear atomically
static inline int sock_error(struct sock *sk)
int err;
if (likely(!sk->sk_err))
return 0;
err = xchg(&sk->sk_err, 0);
return -err;
static inline unsigned long sock_wspace(struct sock *sk)
int amt = 0;
if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
amt = sk->sk_sndbuf - atomic_read(&sk->sk_wmem_alloc);
if (amt < 0)
amt = 0;
return amt;
static inline void sk_wake_async(struct sock *sk, int how, int band)
if (sk->sk_socket && sk->sk_socket->fasync_list)
sock_wake_async(sk->sk_socket, how, band);
#define SOCK_MIN_SNDBUF 2048
#define SOCK_MIN_RCVBUF 256
static inline void sk_stream_moderate_sndbuf(struct sock *sk)
if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK)) {
sk->sk_sndbuf = min(sk->sk_sndbuf, sk->sk_wmem_queued >> 1);
sk->sk_sndbuf = max(sk->sk_sndbuf, SOCK_MIN_SNDBUF);
struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp);
static inline struct page *sk_stream_alloc_page(struct sock *sk)
struct page *page = NULL;
page = alloc_pages(sk->sk_allocation, 0);
if (!page) {
return page;
* Default write policy as shown to user space via poll/select/SIGIO
static inline int sock_writeable(const struct sock *sk)
return atomic_read(&sk->sk_wmem_alloc) < (sk->sk_sndbuf >> 1);
static inline gfp_t gfp_any(void)
return in_atomic() ? GFP_ATOMIC : GFP_KERNEL;
static inline long sock_rcvtimeo(const struct sock *sk, int noblock)
return noblock ? 0 : sk->sk_rcvtimeo;
static inline long sock_sndtimeo(const struct sock *sk, int noblock)
return noblock ? 0 : sk->sk_sndtimeo;
static inline int sock_rcvlowat(const struct sock *sk, int waitall, int len)
return (waitall ? len : min_t(int, sk->sk_rcvlowat, len)) ? : 1;
/* Alas, with timeout socket operations are not restartable.
* Compare this to poll().
static inline int sock_intr_errno(long timeo)
extern void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
struct sk_buff *skb);
static __inline__ void
sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
ktime_t kt = skb->tstamp;
if (sock_flag(sk, SOCK_RCVTSTAMP))
__sock_recv_timestamp(msg, sk, skb);
sk->sk_stamp = kt;
* sk_eat_skb - Release a skb if it is no longer needed
* @sk: socket to eat this skb from
* @skb: socket buffer to eat
* @copied_early: flag indicating whether DMA operations copied this data early
* This routine must be called with interrupts disabled or with the socket
* locked so that the sk_buff queue operation is ok.
static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb, int copied_early)
__skb_unlink(skb, &sk->sk_receive_queue);
if (!copied_early)
__skb_queue_tail(&sk->sk_async_wait_queue, skb);
static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb, int copied_early)
__skb_unlink(skb, &sk->sk_receive_queue);
extern void sock_enable_timestamp(struct sock *sk);
extern int sock_get_timestamp(struct sock *, struct timeval __user *);
extern int sock_get_timestampns(struct sock *, struct timespec __user *);
* Enable debug/info messages
extern int net_msg_warn;
#define NETDEBUG(fmt, args...) \
do { if (net_msg_warn) printk(fmt,##args); } while (0)
#define LIMIT_NETDEBUG(fmt, args...) \
do { if (net_msg_warn && net_ratelimit()) printk(fmt,##args); } while(0)
* Macros for sleeping on a socket. Use them like this:
* if (condition)
* schedule();
* N.B. These are now obsolete and were, afaik, only ever used in DECnet
* and when the last use of them in DECnet has gone, I'm intending to
* remove them.
#define SOCK_SLEEP_PRE(sk) { struct task_struct *tsk = current; \
tsk->state = TASK_INTERRUPTIBLE; \
add_wait_queue((sk)->sk_sleep, &wait); \
#define SOCK_SLEEP_POST(sk) tsk->state = TASK_RUNNING; \
remove_wait_queue((sk)->sk_sleep, &wait); \
lock_sock(sk); \
extern __u32 sysctl_wmem_max;
extern __u32 sysctl_rmem_max;
extern void sk_init(void);
extern int sysctl_optmem_max;
extern __u32 sysctl_wmem_default;
extern __u32 sysctl_rmem_default;
#endif /* _SOCK_H */