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remarkable-linux/include/net/sock.h
Hans Verkuil 626cf23660 poll: add poll_requested_events() and poll_does_not_wait() functions 
In some cases the poll() implementation in a driver has to do different
things depending on the events the caller wants to poll for.  An example
is when a driver needs to start a DMA engine if the caller polls for
POLLIN, but doesn't want to do that if POLLIN is not requested but instead
only POLLOUT or POLLPRI is requested.  This is something that can happen
in the video4linux subsystem among others.

Unfortunately, the current epoll/poll/select implementation doesn't
provide that information reliably.  The poll_table_struct does have it: it
has a key field with the event mask.  But once a poll() call matches one
or more bits of that mask any following poll() calls are passed a NULL
poll_table pointer.

Also, the eventpoll implementation always left the key field at ~0 instead
of using the requested events mask.

This was changed in eventpoll.c so the key field now contains the actual
events that should be polled for as set by the caller.

The solution to the NULL poll_table pointer is to set the qproc field to
NULL in poll_table once poll() matches the events, not the poll_table
pointer itself.  That way drivers can obtain the mask through a new
poll_requested_events inline.

The poll_table_struct can still be NULL since some kernel code calls it
internally (netfs_state_poll() in ./drivers/staging/pohmelfs/netfs.h).  In
that case poll_requested_events() returns ~0 (i.e.  all events).

Very rarely drivers might want to know whether poll_wait will actually
wait.  If another earlier file descriptor in the set already matched the
events the caller wanted to wait for, then the kernel will return from the
select() call without waiting.  This might be useful information in order
to avoid doing expensive work.

A new helper function poll_does_not_wait() is added that drivers can use
to detect this situation.  This is now used in sock_poll_wait() in
include/net/sock.h.  This was the only place in the kernel that needed
this information.

Drivers should no longer access any of the poll_table internals, but use
the poll_requested_events() and poll_does_not_wait() access functions
instead.  In order to enforce that the poll_table fields are now prepended
with an underscore and a comment was added warning against using them
directly.

This required a change in unix_dgram_poll() in unix/af_unix.c which used
the key field to get the requested events.  It's been replaced by a call
to poll_requested_events().

For qproc it was especially important to change its name since the
behavior of that field changes with this patch since this function pointer
can now be NULL when that wasn't possible in the past.

Any driver accessing the qproc or key fields directly will now fail to compile.

Some notes regarding the correctness of this patch: the driver's poll()
function is called with a 'struct poll_table_struct *wait' argument.  This
pointer may or may not be NULL, drivers can never rely on it being one or
the other as that depends on whether or not an earlier file descriptor in
the select()'s fdset matched the requested events.

There are only three things a driver can do with the wait argument:

1) obtain the key field:

	events = wait ? wait->key : ~0;

   This will still work although it should be replaced with the new
   poll_requested_events() function (which does exactly the same).
   This will now even work better, since wait is no longer set to NULL
   unnecessarily.

2) use the qproc callback. This could be deadly since qproc can now be
   NULL. Renaming qproc should prevent this from happening. There are no
   kernel drivers that actually access this callback directly, BTW.

3) test whether wait == NULL to determine whether poll would return without
   waiting. This is no longer sufficient as the correct test is now
   wait == NULL || wait->_qproc == NULL.

   However, the worst that can happen here is a slight performance hit in
   the case where wait != NULL and wait->_qproc == NULL. In that case the
   driver will assume that poll_wait() will actually add the fd to the set
   of waiting file descriptors. Of course, poll_wait() will not do that
   since it tests for wait->_qproc. This will not break anything, though.

   There is only one place in the whole kernel where this happens
   (sock_poll_wait() in include/net/sock.h) and that code will be replaced
   by a call to poll_does_not_wait() in the next patch.

   Note that even if wait->_qproc != NULL drivers cannot rely on poll_wait()
   actually waiting. The next file descriptor from the set might match the
   event mask and thus any possible waits will never happen.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Jonathan Corbet <corbet@lwn.net>
Reviewed-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-23 16:58:38 -07:00

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/*
* 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!minyard@relay.EU.net>
* Florian La Roche <flla@stud.uni-sb.de>
*
* 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/hardirq.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/list_nulls.h>
#include <linux/timer.h>
#include <linux/cache.h>
#include <linux/lockdep.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h> /* struct sk_buff */
#include <linux/mm.h>
#include <linux/security.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/memcontrol.h>
#include <linux/res_counter.h>
#include <linux/static_key.h>
#include <linux/aio.h>
#include <linux/sched.h>
#include <linux/filter.h>
#include <linux/rculist_nulls.h>
#include <linux/poll.h>
#include <linux/atomic.h>
#include <net/dst.h>
#include <net/checksum.h>
struct cgroup;
struct cgroup_subsys;
#ifdef CONFIG_NET
int mem_cgroup_sockets_init(struct cgroup *cgrp, struct cgroup_subsys *ss);
void mem_cgroup_sockets_destroy(struct cgroup *cgrp);
#else
static inline
int mem_cgroup_sockets_init(struct cgroup *cgrp, struct cgroup_subsys *ss)
{
return 0;
}
static inline
void mem_cgroup_sockets_destroy(struct cgroup *cgrp)
{
}
#endif
/*
* 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_DEBUGGING
#ifdef SOCK_DEBUGGING
#define SOCK_DEBUG(sk, msg...) do { if ((sk) && sock_flag((sk), SOCK_DBG)) \
printk(KERN_DEBUG msg); } while (0)
#else
/* Validate arguments and do nothing */
static inline __printf(2, 3)
void SOCK_DEBUG(struct sock *sk, const char *msg, ...)
{
}
#endif
/* 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):
*/
#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lockdep_map dep_map;
#endif
} socket_lock_t;
struct sock;
struct proto;
struct net;
/**
* struct sock_common - minimal network layer representation of sockets
* @skc_daddr: Foreign IPv4 addr
* @skc_rcv_saddr: Bound local IPv4 addr
* @skc_hash: hash value used with various protocol lookup tables
* @skc_u16hashes: two u16 hash values used by UDP lookup tables
* @skc_family: network address family
* @skc_state: Connection state
* @skc_reuse: %SO_REUSEADDR setting
* @skc_bound_dev_if: bound device index if != 0
* @skc_bind_node: bind hash linkage for various protocol lookup tables
* @skc_portaddr_node: second hash linkage for UDP/UDP-Lite protocol
* @skc_prot: protocol handlers inside a network family
* @skc_net: reference to the network namespace of this socket
* @skc_node: main hash linkage for various protocol lookup tables
* @skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol
* @skc_tx_queue_mapping: tx queue number for this connection
* @skc_refcnt: reference count
*
* This is the minimal network layer representation of sockets, the header
* for struct sock and struct inet_timewait_sock.
*/
struct sock_common {
/* skc_daddr and skc_rcv_saddr must be grouped :
* cf INET_MATCH() and INET_TW_MATCH()
*/
__be32 skc_daddr;
__be32 skc_rcv_saddr;
union {
unsigned int skc_hash;
__u16 skc_u16hashes[2];
};
unsigned short skc_family;
volatile unsigned char skc_state;
unsigned char skc_reuse;
int skc_bound_dev_if;
union {
struct hlist_node skc_bind_node;
struct hlist_nulls_node skc_portaddr_node;
};
struct proto *skc_prot;
#ifdef CONFIG_NET_NS
struct net *skc_net;
#endif
/*
* fields between dontcopy_begin/dontcopy_end
* are not copied in sock_copy()
*/
/* private: */
int skc_dontcopy_begin[0];
/* public: */
union {
struct hlist_node skc_node;
struct hlist_nulls_node skc_nulls_node;
};
int skc_tx_queue_mapping;
atomic_t skc_refcnt;
/* private: */
int skc_dontcopy_end[0];
/* public: */
};
struct cg_proto;
/**
* 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_wq: sock wait queue and async head
* @sk_dst_cache: destination cache
* @sk_dst_lock: destination cache lock
* @sk_policy: flow policy
* @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, %SO_TIMESTAMPING settings
* @sk_no_check: %SO_NO_CHECK setting, wether or not checkup packets
* @sk_route_caps: route capabilities (e.g. %NETIF_F_TSO)
* @sk_route_nocaps: forbidden route capabilities (e.g NETIF_F_GSO_MASK)
* @sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
* @sk_gso_max_size: Maximum GSO segment size to build
* @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/udp drops counter
* @sk_ack_backlog: current listen backlog
* @sk_max_ack_backlog: listen backlog set in listen()
* @sk_priority: %SO_PRIORITY setting
* @sk_cgrp_prioidx: socket group's priority map index
* @sk_type: socket type (%SOCK_STREAM, etc)
* @sk_protocol: which protocol this socket belongs in this network family
* @sk_peer_pid: &struct pid for this socket's peer
* @sk_peer_cred: %SO_PEERCRED setting
* @sk_rcvlowat: %SO_RCVLOWAT setting
* @sk_rcvtimeo: %SO_RCVTIMEO setting
* @sk_sndtimeo: %SO_SNDTIMEO setting
* @sk_rxhash: flow hash received from netif layer
* @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_classid: this socket's cgroup classid
* @sk_cgrp: this socket's cgroup-specific proto data
* @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_node __sk_common.skc_node
#define sk_nulls_node __sk_common.skc_nulls_node
#define sk_refcnt __sk_common.skc_refcnt
#define sk_tx_queue_mapping __sk_common.skc_tx_queue_mapping
#define sk_dontcopy_begin __sk_common.skc_dontcopy_begin
#define sk_dontcopy_end __sk_common.skc_dontcopy_end
#define sk_hash __sk_common.skc_hash
#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_bind_node __sk_common.skc_bind_node
#define sk_prot __sk_common.skc_prot
#define sk_net __sk_common.skc_net
socket_lock_t sk_lock;
struct sk_buff_head sk_receive_queue;
/*
* 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.
* Note : rmem_alloc is in this structure to fill a hole
* on 64bit arches, not because its logically part of
* backlog.
*/
struct {
atomic_t rmem_alloc;
int len;
struct sk_buff *head;
struct sk_buff *tail;
} sk_backlog;
#define sk_rmem_alloc sk_backlog.rmem_alloc
int sk_forward_alloc;
#ifdef CONFIG_RPS
__u32 sk_rxhash;
#endif
atomic_t sk_drops;
int sk_rcvbuf;
struct sk_filter __rcu *sk_filter;
struct socket_wq __rcu *sk_wq;
#ifdef CONFIG_NET_DMA
struct sk_buff_head sk_async_wait_queue;
#endif
#ifdef CONFIG_XFRM
struct xfrm_policy *sk_policy[2];
#endif
unsigned long sk_flags;
struct dst_entry *sk_dst_cache;
spinlock_t sk_dst_lock;
atomic_t sk_wmem_alloc;
atomic_t sk_omem_alloc;
int sk_sndbuf;
struct sk_buff_head sk_write_queue;
kmemcheck_bitfield_begin(flags);
unsigned int sk_shutdown : 2,
sk_no_check : 2,
sk_userlocks : 4,
sk_protocol : 8,
sk_type : 16;
kmemcheck_bitfield_end(flags);
int sk_wmem_queued;
gfp_t sk_allocation;
netdev_features_t sk_route_caps;
netdev_features_t sk_route_nocaps;
int sk_gso_type;
unsigned int sk_gso_max_size;
int sk_rcvlowat;
unsigned long sk_lingertime;
struct sk_buff_head sk_error_queue;
struct proto *sk_prot_creator;
rwlock_t sk_callback_lock;
int sk_err,
sk_err_soft;
unsigned short sk_ack_backlog;
unsigned short sk_max_ack_backlog;
__u32 sk_priority;
#ifdef CONFIG_CGROUPS
__u32 sk_cgrp_prioidx;
#endif
struct pid *sk_peer_pid;
const struct cred *sk_peer_cred;
long sk_rcvtimeo;
long sk_sndtimeo;
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;
__s32 sk_peek_off;
int sk_write_pending;
#ifdef CONFIG_SECURITY
void *sk_security;
#endif
__u32 sk_mark;
u32 sk_classid;
struct cg_proto *sk_cgrp;
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);
};
static inline int sk_peek_offset(struct sock *sk, int flags)
{
if ((flags & MSG_PEEK) && (sk->sk_peek_off >= 0))
return sk->sk_peek_off;
else
return 0;
}
static inline void sk_peek_offset_bwd(struct sock *sk, int val)
{
if (sk->sk_peek_off >= 0) {
if (sk->sk_peek_off >= val)
sk->sk_peek_off -= val;
else
sk->sk_peek_off = 0;
}
}
static inline void sk_peek_offset_fwd(struct sock *sk, int val)
{
if (sk->sk_peek_off >= 0)
sk->sk_peek_off += val;
}
/*
* Hashed lists helper routines
*/
static inline struct sock *sk_entry(const struct hlist_node *node)
{
return hlist_entry(node, struct sock, sk_node);
}
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_nulls_head(const struct hlist_nulls_head *head)
{
return hlist_nulls_entry(head->first, struct sock, sk_nulls_node);
}
static inline struct sock *sk_nulls_head(const struct hlist_nulls_head *head)
{
return hlist_nulls_empty(head) ? NULL : __sk_nulls_head(head);
}
static inline struct sock *sk_next(const struct sock *sk)
{
return sk->sk_node.next ?
hlist_entry(sk->sk_node.next, struct sock, sk_node) : NULL;
}
static inline struct sock *sk_nulls_next(const struct sock *sk)
{
return (!is_a_nulls(sk->sk_nulls_node.next)) ?
hlist_nulls_entry(sk->sk_nulls_node.next,
struct sock, sk_nulls_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_nulls_node_init(struct hlist_nulls_node *node)
{
node->pprev = NULL;
}
static __inline__ void __sk_del_node(struct sock *sk)
{
__hlist_del(&sk->sk_node);
}
/* NB: equivalent to hlist_del_init_rcu */
static __inline__ int __sk_del_node_init(struct sock *sk)
{
if (sk_hashed(sk)) {
__sk_del_node(sk);
sk_node_init(&sk->sk_node);
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
modifications.
*/
static inline void sock_hold(struct sock *sk)
{
atomic_inc(&sk->sk_refcnt);
}
/* 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)
{
atomic_dec(&sk->sk_refcnt);
}
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);
__sock_put(sk);
}
return rc;
}
#define sk_del_node_init_rcu(sk) sk_del_node_init(sk)
static __inline__ int __sk_nulls_del_node_init_rcu(struct sock *sk)
{
if (sk_hashed(sk)) {
hlist_nulls_del_init_rcu(&sk->sk_nulls_node);
return 1;
}
return 0;
}
static __inline__ int sk_nulls_del_node_init_rcu(struct sock *sk)
{
int rc = __sk_nulls_del_node_init_rcu(sk);
if (rc) {
/* paranoid for a while -acme */
WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
__sock_put(sk);
}
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)
{
sock_hold(sk);
__sk_add_node(sk, list);
}
static __inline__ void sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
{
sock_hold(sk);
hlist_add_head_rcu(&sk->sk_node, list);
}
static __inline__ void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
{
hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);
}
static __inline__ void sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
{
sock_hold(sk);
__sk_nulls_add_node_rcu(sk, list);
}
static __inline__ void __sk_del_bind_node(struct sock *sk)
{
__hlist_del(&sk->sk_bind_node);
}
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_rcu(__sk, node, list) \
hlist_for_each_entry_rcu(__sk, node, list, sk_node)
#define sk_nulls_for_each(__sk, node, list) \
hlist_nulls_for_each_entry(__sk, node, list, sk_nulls_node)
#define sk_nulls_for_each_rcu(__sk, node, list) \
hlist_nulls_for_each_entry_rcu(__sk, node, list, sk_nulls_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_nulls_for_each_from(__sk, node) \
if (__sk && ({ node = &(__sk)->sk_nulls_node; 1; })) \
hlist_nulls_for_each_entry_from(__sk, node, sk_nulls_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_DEAD,
SOCK_DONE,
SOCK_URGINLINE,
SOCK_KEEPOPEN,
SOCK_LINGER,
SOCK_DESTROY,
SOCK_BROADCAST,
SOCK_TIMESTAMP,
SOCK_ZAPPED,
SOCK_USE_WRITE_QUEUE, /* whether to call sk->sk_write_space in sock_wfree */
SOCK_DBG, /* %SO_DEBUG setting */
SOCK_RCVTSTAMP, /* %SO_TIMESTAMP setting */
SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */
SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
SOCK_QUEUE_SHRUNK, /* write queue has been shrunk recently */
SOCK_TIMESTAMPING_TX_HARDWARE, /* %SOF_TIMESTAMPING_TX_HARDWARE */
SOCK_TIMESTAMPING_TX_SOFTWARE, /* %SOF_TIMESTAMPING_TX_SOFTWARE */
SOCK_TIMESTAMPING_RX_HARDWARE, /* %SOF_TIMESTAMPING_RX_HARDWARE */
SOCK_TIMESTAMPING_RX_SOFTWARE, /* %SOF_TIMESTAMPING_RX_SOFTWARE */
SOCK_TIMESTAMPING_SOFTWARE, /* %SOF_TIMESTAMPING_SOFTWARE */
SOCK_TIMESTAMPING_RAW_HARDWARE, /* %SOF_TIMESTAMPING_RAW_HARDWARE */
SOCK_TIMESTAMPING_SYS_HARDWARE, /* %SOF_TIMESTAMPING_SYS_HARDWARE */
SOCK_FASYNC, /* fasync() active */
SOCK_RXQ_OVFL,
SOCK_ZEROCOPY, /* buffers from userspace */
SOCK_WIFI_STATUS, /* push wifi status to userspace */
SOCK_NOFCS, /* Tell NIC not to do the Ethernet FCS.
* Will use last 4 bytes of packet sent from
* user-space instead.
*/
};
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)
{
sk->sk_ack_backlog--;
}
static inline void sk_acceptq_added(struct sock *sk)
{
sk->sk_ack_backlog++;
}
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;
}
/* OOB backlog add */
static inline void __sk_add_backlog(struct sock *sk, struct sk_buff *skb)
{
/* dont let skb dst not refcounted, we are going to leave rcu lock */
skb_dst_force(skb);
if (!sk->sk_backlog.tail)
sk->sk_backlog.head = skb;
else
sk->sk_backlog.tail->next = skb;
sk->sk_backlog.tail = skb;
skb->next = NULL;
}
/*
* Take into account size of receive queue and backlog queue
* Do not take into account this skb truesize,
* to allow even a single big packet to come.
*/
static inline bool sk_rcvqueues_full(const struct sock *sk, const struct sk_buff *skb)
{
unsigned int qsize = sk->sk_backlog.len + atomic_read(&sk->sk_rmem_alloc);
return qsize > sk->sk_rcvbuf;
}
/* The per-socket spinlock must be held here. */
static inline __must_check int sk_add_backlog(struct sock *sk, struct sk_buff *skb)
{
if (sk_rcvqueues_full(sk, skb))
return -ENOBUFS;
__sk_add_backlog(sk, skb);
sk->sk_backlog.len += skb->truesize;
return 0;
}
static inline int sk_backlog_rcv(struct sock *sk, struct sk_buff *skb)
{
return sk->sk_backlog_rcv(sk, skb);
}
static inline void sock_rps_record_flow(const struct sock *sk)
{
#ifdef CONFIG_RPS
struct rps_sock_flow_table *sock_flow_table;
rcu_read_lock();
sock_flow_table = rcu_dereference(rps_sock_flow_table);
rps_record_sock_flow(sock_flow_table, sk->sk_rxhash);
rcu_read_unlock();
#endif
}
static inline void sock_rps_reset_flow(const struct sock *sk)
{
#ifdef CONFIG_RPS
struct rps_sock_flow_table *sock_flow_table;
rcu_read_lock();
sock_flow_table = rcu_dereference(rps_sock_flow_table);
rps_reset_sock_flow(sock_flow_table, sk->sk_rxhash);
rcu_read_unlock();
#endif
}
static inline void sock_rps_save_rxhash(struct sock *sk,
const struct sk_buff *skb)
{
#ifdef CONFIG_RPS
if (unlikely(sk->sk_rxhash != skb->rxhash)) {
sock_rps_reset_flow(sk);
sk->sk_rxhash = skb->rxhash;
}
#endif
}
static inline void sock_rps_reset_rxhash(struct sock *sk)
{
#ifdef CONFIG_RPS
sock_rps_reset_flow(sk);
sk->sk_rxhash = 0;
#endif
}
#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;
struct raw_hashinfo;
struct module;
/* 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);
void (*destroy)(struct sock *sk);
void (*shutdown)(struct sock *sk, int how);
int (*setsockopt)(struct sock *sk, int level,
int optname, char __user *optval,
unsigned int optlen);
int (*getsockopt)(struct sock *sk, int level,
int optname, char __user *optval,
int __user *option);
#ifdef CONFIG_COMPAT
int (*compat_setsockopt)(struct sock *sk,
int level,
int optname, char __user *optval,
unsigned int optlen);
int (*compat_getsockopt)(struct sock *sk,
int level,
int optname, char __user *optval,
int __user *option);
int (*compat_ioctl)(struct sock *sk,
unsigned int cmd, unsigned long arg);
#endif
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);
void (*rehash)(struct sock *sk);
int (*get_port)(struct sock *sk, unsigned short snum);
void (*clear_sk)(struct sock *sk, int size);
/* Keeping track of sockets in use */
#ifdef CONFIG_PROC_FS
unsigned int inuse_idx;
#endif
/* Memory pressure */
void (*enter_memory_pressure)(struct sock *sk);
atomic_long_t *memory_allocated; /* Current allocated memory. */
struct percpu_counter *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;
long *sysctl_mem;
int *sysctl_wmem;
int *sysctl_rmem;
int max_header;
bool no_autobind;
struct kmem_cache *slab;
unsigned int obj_size;
int slab_flags;
struct percpu_counter *orphan_count;
struct request_sock_ops *rsk_prot;
struct timewait_sock_ops *twsk_prot;
union {
struct inet_hashinfo *hashinfo;
struct udp_table *udp_table;
struct raw_hashinfo *raw_hash;
} h;
struct module *owner;
char name[32];
struct list_head node;
#ifdef SOCK_REFCNT_DEBUG
atomic_t socks;
#endif
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
/*
* cgroup specific init/deinit functions. Called once for all
* protocols that implement it, from cgroups populate function.
* This function has to setup any files the protocol want to
* appear in the kmem cgroup filesystem.
*/
int (*init_cgroup)(struct cgroup *cgrp,
struct cgroup_subsys *ss);
void (*destroy_cgroup)(struct cgroup *cgrp);
struct cg_proto *(*proto_cgroup)(struct mem_cgroup *memcg);
#endif
};
struct cg_proto {
void (*enter_memory_pressure)(struct sock *sk);
struct res_counter *memory_allocated; /* Current allocated memory. */
struct percpu_counter *sockets_allocated; /* Current number of sockets. */
int *memory_pressure;
long *sysctl_mem;
/*
* memcg field is used to find which memcg we belong directly
* Each memcg struct can hold more than one cg_proto, so container_of
* won't really cut.
*
* The elegant solution would be having an inverse function to
* proto_cgroup in struct proto, but that means polluting the structure
* for everybody, instead of just for memcg users.
*/
struct mem_cgroup *memcg;
};
extern int proto_register(struct proto *prot, int alloc_slab);
extern void proto_unregister(struct proto *prot);
#ifdef SOCK_REFCNT_DEBUG
static inline void sk_refcnt_debug_inc(struct sock *sk)
{
atomic_inc(&sk->sk_prot->socks);
}
static inline void sk_refcnt_debug_dec(struct sock *sk)
{
atomic_dec(&sk->sk_prot->socks);
printk(KERN_DEBUG "%s socket %p released, %d are still alive\n",
sk->sk_prot->name, sk, atomic_read(&sk->sk_prot->socks));
}
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));
}
#else /* SOCK_REFCNT_DEBUG */
#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 */
#if defined(CONFIG_CGROUP_MEM_RES_CTLR_KMEM) && defined(CONFIG_NET)
extern struct static_key memcg_socket_limit_enabled;
static inline struct cg_proto *parent_cg_proto(struct proto *proto,
struct cg_proto *cg_proto)
{
return proto->proto_cgroup(parent_mem_cgroup(cg_proto->memcg));
}
#define mem_cgroup_sockets_enabled static_key_false(&memcg_socket_limit_enabled)
#else
#define mem_cgroup_sockets_enabled 0
static inline struct cg_proto *parent_cg_proto(struct proto *proto,
struct cg_proto *cg_proto)
{
return NULL;
}
#endif
static inline bool sk_has_memory_pressure(const struct sock *sk)
{
return sk->sk_prot->memory_pressure != NULL;
}
static inline bool sk_under_memory_pressure(const struct sock *sk)
{
if (!sk->sk_prot->memory_pressure)
return false;
if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
return !!*sk->sk_cgrp->memory_pressure;
return !!*sk->sk_prot->memory_pressure;
}
static inline void sk_leave_memory_pressure(struct sock *sk)
{
int *memory_pressure = sk->sk_prot->memory_pressure;
if (!memory_pressure)
return;
if (*memory_pressure)
*memory_pressure = 0;
if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
struct cg_proto *cg_proto = sk->sk_cgrp;
struct proto *prot = sk->sk_prot;
for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
if (*cg_proto->memory_pressure)
*cg_proto->memory_pressure = 0;
}
}
static inline void sk_enter_memory_pressure(struct sock *sk)
{
if (!sk->sk_prot->enter_memory_pressure)
return;
if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
struct cg_proto *cg_proto = sk->sk_cgrp;
struct proto *prot = sk->sk_prot;
for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
cg_proto->enter_memory_pressure(sk);
}
sk->sk_prot->enter_memory_pressure(sk);
}
static inline long sk_prot_mem_limits(const struct sock *sk, int index)
{
long *prot = sk->sk_prot->sysctl_mem;
if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
prot = sk->sk_cgrp->sysctl_mem;
return prot[index];
}
static inline void memcg_memory_allocated_add(struct cg_proto *prot,
unsigned long amt,
int *parent_status)
{
struct res_counter *fail;
int ret;
ret = res_counter_charge_nofail(prot->memory_allocated,
amt << PAGE_SHIFT, &fail);
if (ret < 0)
*parent_status = OVER_LIMIT;
}
static inline void memcg_memory_allocated_sub(struct cg_proto *prot,
unsigned long amt)
{
res_counter_uncharge(prot->memory_allocated, amt << PAGE_SHIFT);
}
static inline u64 memcg_memory_allocated_read(struct cg_proto *prot)
{
u64 ret;
ret = res_counter_read_u64(prot->memory_allocated, RES_USAGE);
return ret >> PAGE_SHIFT;
}
static inline long
sk_memory_allocated(const struct sock *sk)
{
struct proto *prot = sk->sk_prot;
if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
return memcg_memory_allocated_read(sk->sk_cgrp);
return atomic_long_read(prot->memory_allocated);
}
static inline long
sk_memory_allocated_add(struct sock *sk, int amt, int *parent_status)
{
struct proto *prot = sk->sk_prot;
if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
memcg_memory_allocated_add(sk->sk_cgrp, amt, parent_status);
/* update the root cgroup regardless */
atomic_long_add_return(amt, prot->memory_allocated);
return memcg_memory_allocated_read(sk->sk_cgrp);
}
return atomic_long_add_return(amt, prot->memory_allocated);
}
static inline void
sk_memory_allocated_sub(struct sock *sk, int amt)
{
struct proto *prot = sk->sk_prot;
if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
memcg_memory_allocated_sub(sk->sk_cgrp, amt);
atomic_long_sub(amt, prot->memory_allocated);
}
static inline void sk_sockets_allocated_dec(struct sock *sk)
{
struct proto *prot = sk->sk_prot;
if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
struct cg_proto *cg_proto = sk->sk_cgrp;
for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
percpu_counter_dec(cg_proto->sockets_allocated);
}
percpu_counter_dec(prot->sockets_allocated);
}
static inline void sk_sockets_allocated_inc(struct sock *sk)
{
struct proto *prot = sk->sk_prot;
if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
struct cg_proto *cg_proto = sk->sk_cgrp;
for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
percpu_counter_inc(cg_proto->sockets_allocated);
}
percpu_counter_inc(prot->sockets_allocated);
}
static inline int
sk_sockets_allocated_read_positive(struct sock *sk)
{
struct proto *prot = sk->sk_prot;
if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
return percpu_counter_sum_positive(sk->sk_cgrp->sockets_allocated);
return percpu_counter_sum_positive(prot->sockets_allocated);
}
static inline int
proto_sockets_allocated_sum_positive(struct proto *prot)
{
return percpu_counter_sum_positive(prot->sockets_allocated);
}
static inline long
proto_memory_allocated(struct proto *prot)
{
return atomic_long_read(prot->memory_allocated);
}
static inline bool
proto_memory_pressure(struct proto *prot)
{
if (!prot->memory_pressure)
return false;
return !!*prot->memory_pressure;
}
#ifdef CONFIG_PROC_FS
/* Called with local bh disabled */
extern void sock_prot_inuse_add(struct net *net, struct proto *prot, int inc);
extern int sock_prot_inuse_get(struct net *net, struct proto *proto);
#else
static void inline sock_prot_inuse_add(struct net *net, struct proto *prot,
int inc)
{
}
#endif
/* 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)
{
sk->sk_prot->unhash(sk);
sk->sk_prot->hash(sk);
}
void sk_prot_clear_portaddr_nulls(struct sock *sk, int size);
/* About 10 seconds */
#define SOCK_DESTROY_TIME (10*HZ)
/* Sockets 0-1023 can't be bound to unless you are superuser */
#define PROT_SOCK 1024
#define SHUTDOWN_MASK 3
#define RCV_SHUTDOWN 1
#define SEND_SHUTDOWN 2
#define SOCK_SNDBUF_LOCK 1
#define SOCK_RCVBUF_LOCK 2
#define SOCK_BINDADDR_LOCK 4
#define SOCK_BINDPORT_LOCK 8
/* 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_QUANTUM ((int)PAGE_SIZE)
#define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)
#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))
return;
if (sk->sk_forward_alloc >= SK_MEM_QUANTUM)
__sk_mem_reclaim(sk);
}
static inline void sk_mem_reclaim_partial(struct sock *sk)
{
if (!sk_has_account(sk))
return;
if (sk->sk_forward_alloc > SK_MEM_QUANTUM)
__sk_mem_reclaim(sk);
}
static inline void sk_mem_charge(struct sock *sk, int size)
{
if (!sk_has_account(sk))
return;
sk->sk_forward_alloc -= size;
}
static inline void sk_mem_uncharge(struct sock *sk, int size)
{
if (!sk_has_account(sk))
return;
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);
__kfree_skb(skb);
}
/* 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), \
SINGLE_DEPTH_NESTING)
#define bh_unlock_sock(__sk) spin_unlock(&((__sk)->sk_lock.slock))
extern bool lock_sock_fast(struct sock *sk);
/**
* unlock_sock_fast - complement of lock_sock_fast
* @sk: socket
* @slow: slow mode
*
* fast unlock socket for user context.
* If slow mode is on, we call regular release_sock()
*/
static inline void unlock_sock_fast(struct sock *sk, bool slow)
{
if (slow)
release_sock(sk);
else
spin_unlock_bh(&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 void sk_release_kernel(struct sock *sk);
extern struct sock *sk_clone_lock(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,
unsigned 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 struct sk_buff *sock_alloc_send_pskb(struct sock *sk,
unsigned long header_len,
unsigned long data_len,
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);
#ifdef CONFIG_CGROUPS
extern void sock_update_classid(struct sock *sk);
#else
static inline void sock_update_classid(struct sock *sk)
{
}
#endif
/*
* 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 *, unsigned 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, unsigned 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, unsigned 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);
extern void sk_filter_release_rcu(struct rcu_head *rcu);
/**
* sk_filter_release - release a socket filter
* @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))
call_rcu(&fp->rcu, sk_filter_release_rcu);
}
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);
sk_filter_release(fp);
}
static inline void sk_filter_charge(struct sock *sk, struct sk_filter *fp)
{
atomic_inc(&fp->refcnt);
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))
sk_free(sk);
}
extern int sk_receive_skb(struct sock *sk, struct sk_buff *skb,
const int nested);
static inline void sk_tx_queue_set(struct sock *sk, int tx_queue)
{
sk->sk_tx_queue_mapping = tx_queue;
}
static inline void sk_tx_queue_clear(struct sock *sk)
{
sk->sk_tx_queue_mapping = -1;
}
static inline int sk_tx_queue_get(const struct sock *sk)
{
return sk ? sk->sk_tx_queue_mapping : -1;
}
static inline void sk_set_socket(struct sock *sk, struct socket *sock)
{
sk_tx_queue_clear(sk);
sk->sk_socket = sock;
}
static inline wait_queue_head_t *sk_sleep(struct sock *sk)
{
BUILD_BUG_ON(offsetof(struct socket_wq, wait) != 0);
return &rcu_dereference_raw(sk->sk_wq)->wait;
}
/* 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)
{
write_lock_bh(&sk->sk_callback_lock);
sock_set_flag(sk, SOCK_DEAD);
sk_set_socket(sk, NULL);
sk->sk_wq = NULL;
write_unlock_bh(&sk->sk_callback_lock);
}
static inline void sock_graft(struct sock *sk, struct socket *parent)
{
write_lock_bh(&sk->sk_callback_lock);
sk->sk_wq = parent->wq;
parent->sk = sk;
sk_set_socket(sk, parent);
security_sock_graft(sk, parent);
write_unlock_bh(&sk->sk_callback_lock);
}
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 rcu_dereference_check(sk->sk_dst_cache, sock_owned_by_user(sk) ||
lockdep_is_held(&sk->sk_lock.slock));
}
static inline struct dst_entry *
sk_dst_get(struct sock *sk)
{
struct dst_entry *dst;
rcu_read_lock();
dst = rcu_dereference(sk->sk_dst_cache);
if (dst)
dst_hold(dst);
rcu_read_unlock();
return dst;
}
extern void sk_reset_txq(struct sock *sk);
static inline void dst_negative_advice(struct sock *sk)
{
struct dst_entry *ndst, *dst = __sk_dst_get(sk);
if (dst && dst->ops->negative_advice) {
ndst = dst->ops->negative_advice(dst);
if (ndst != dst) {
rcu_assign_pointer(sk->sk_dst_cache, ndst);
sk_reset_txq(sk);
}
}
}
static inline void
__sk_dst_set(struct sock *sk, struct dst_entry *dst)
{
struct dst_entry *old_dst;
sk_tx_queue_clear(sk);
/*
* This can be called while sk is owned by the caller only,
* with no state that can be checked in a rcu_dereference_check() cond
*/
old_dst = rcu_dereference_raw(sk->sk_dst_cache);
rcu_assign_pointer(sk->sk_dst_cache, dst);
dst_release(old_dst);
}
static inline void
sk_dst_set(struct sock *sk, struct dst_entry *dst)
{
spin_lock(&sk->sk_dst_lock);
__sk_dst_set(sk, dst);
spin_unlock(&sk->sk_dst_lock);
}
static inline void
__sk_dst_reset(struct sock *sk)
{
__sk_dst_set(sk, NULL);
}
static inline void
sk_dst_reset(struct sock *sk)
{
spin_lock(&sk->sk_dst_lock);
__sk_dst_reset(sk);
spin_unlock(&sk->sk_dst_lock);
}
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 void sk_nocaps_add(struct sock *sk, netdev_features_t flags)
{
sk->sk_route_nocaps |= flags;
sk->sk_route_caps &= ~flags;
}
static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
char __user *from, char *to,
int copy, int offset)
{
if (skb->ip_summed == CHECKSUM_NONE) {
int err = 0;
__wsum csum = csum_and_copy_from_user(from, to, copy, 0, &err);
if (err)
return err;
skb->csum = csum_block_add(skb->csum, csum, offset);
} else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
if (!access_ok(VERIFY_READ, from, copy) ||
__copy_from_user_nocache(to, from, copy))
return -EFAULT;
} else if (copy_from_user(to, from, copy))
return -EFAULT;
return 0;
}
static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb,
char __user *from, int copy)
{
int err, offset = skb->len;
err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy),
copy, offset);
if (err)
__skb_trim(skb, offset);
return err;
}
static inline int skb_copy_to_page_nocache(struct sock *sk, char __user *from,
struct sk_buff *skb,
struct page *page,
int off, int copy)
{
int err;
err = skb_do_copy_data_nocache(sk, skb, from, page_address(page) + off,
copy, skb->len);
if (err)
return err;
skb->len += copy;
skb->data_len += copy;
skb->truesize += copy;
sk->sk_wmem_queued += copy;
sk_mem_charge(sk, copy);
return 0;
}
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;
}
/**
* sk_wmem_alloc_get - returns write allocations
* @sk: socket
*
* Returns sk_wmem_alloc minus initial offset of one
*/
static inline int sk_wmem_alloc_get(const struct sock *sk)
{
return atomic_read(&sk->sk_wmem_alloc) - 1;
}
/**
* sk_rmem_alloc_get - returns read allocations
* @sk: socket
*
* Returns sk_rmem_alloc
*/
static inline int sk_rmem_alloc_get(const struct sock *sk)
{
return atomic_read(&sk->sk_rmem_alloc);
}
/**
* sk_has_allocations - check if allocations are outstanding
* @sk: socket
*
* Returns true if socket has write or read allocations
*/
static inline int sk_has_allocations(const struct sock *sk)
{
return sk_wmem_alloc_get(sk) || sk_rmem_alloc_get(sk);
}
/**
* wq_has_sleeper - check if there are any waiting processes
* @wq: struct socket_wq
*
* Returns true if socket_wq has waiting processes
*
* The purpose of the wq_has_sleeper and sock_poll_wait is to wrap the memory
* barrier call. They were added due to the race found within the tcp code.
*
* Consider following tcp code paths:
*
* CPU1 CPU2
*
* sys_select receive packet
* ... ...
* __add_wait_queue update tp->rcv_nxt
* ... ...
* tp->rcv_nxt check sock_def_readable
* ... {
* schedule rcu_read_lock();
* wq = rcu_dereference(sk->sk_wq);
* if (wq && waitqueue_active(&wq->wait))
* wake_up_interruptible(&wq->wait)
* ...
* }
*
* The race for tcp fires when the __add_wait_queue changes done by CPU1 stay
* in its cache, and so does the tp->rcv_nxt update on CPU2 side. The CPU1
* could then endup calling schedule and sleep forever if there are no more
* data on the socket.
*
*/
static inline bool wq_has_sleeper(struct socket_wq *wq)
{
/*
* We need to be sure we are in sync with the
* add_wait_queue modifications to the wait queue.
*
* This memory barrier is paired in the sock_poll_wait.
*/
smp_mb();
return wq && waitqueue_active(&wq->wait);
}
/**
* sock_poll_wait - place memory barrier behind the poll_wait call.
* @filp: file
* @wait_address: socket wait queue
* @p: poll_table
*
* See the comments in the wq_has_sleeper function.
*/
static inline void sock_poll_wait(struct file *filp,
wait_queue_head_t *wait_address, poll_table *p)
{
if (!poll_does_not_wait(p) && wait_address) {
poll_wait(filp, wait_address, p);
/*
* We need to be sure we are in sync with the
* socket flags modification.
*
* This memory barrier is paired in the wq_has_sleeper.
*/
smp_mb();
}
}
/*
* 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_orphan(skb);
skb->sk = sk;
skb->destructor = sock_wfree;
/*
* We used to take a refcount on sk, but following operation
* is enough to guarantee sk_free() wont free this sock until
* all in-flight packets are completed
*/
atomic_add(skb->truesize, &sk->sk_wmem_alloc);
}
static inline void skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
{
skb_orphan(skb);
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);
extern int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb);
/*
* 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 (sock_flag(sk, SOCK_FASYNC))
sock_wake_async(sk->sk_socket, how, band);
}
#define SOCK_MIN_SNDBUF 2048
/*
* Since sk_rmem_alloc sums skb->truesize, even a small frame might need
* sizeof(sk_buff) + MTU + padding, unless net driver perform copybreak
*/
#define SOCK_MIN_RCVBUF (2048 + sizeof(struct sk_buff))
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) {
sk_enter_memory_pressure(sk);
sk_stream_moderate_sndbuf(sk);
}
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_softirq() ? 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)
{
return timeo == MAX_SCHEDULE_TIMEOUT ? -ERESTARTSYS : -EINTR;
}
extern void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
struct sk_buff *skb);
extern void __sock_recv_wifi_status(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;
struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
/*
* generate control messages if
* - receive time stamping in software requested (SOCK_RCVTSTAMP
* or SOCK_TIMESTAMPING_RX_SOFTWARE)
* - software time stamp available and wanted
* (SOCK_TIMESTAMPING_SOFTWARE)
* - hardware time stamps available and wanted
* (SOCK_TIMESTAMPING_SYS_HARDWARE or
* SOCK_TIMESTAMPING_RAW_HARDWARE)
*/
if (sock_flag(sk, SOCK_RCVTSTAMP) ||
sock_flag(sk, SOCK_TIMESTAMPING_RX_SOFTWARE) ||
(kt.tv64 && sock_flag(sk, SOCK_TIMESTAMPING_SOFTWARE)) ||
(hwtstamps->hwtstamp.tv64 &&
sock_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE)) ||
(hwtstamps->syststamp.tv64 &&
sock_flag(sk, SOCK_TIMESTAMPING_SYS_HARDWARE)))
__sock_recv_timestamp(msg, sk, skb);
else
sk->sk_stamp = kt;
if (sock_flag(sk, SOCK_WIFI_STATUS) && skb->wifi_acked_valid)
__sock_recv_wifi_status(msg, sk, skb);
}
extern void __sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
struct sk_buff *skb);
static inline void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
struct sk_buff *skb)
{
#define FLAGS_TS_OR_DROPS ((1UL << SOCK_RXQ_OVFL) | \
(1UL << SOCK_RCVTSTAMP) | \
(1UL << SOCK_TIMESTAMPING_RX_SOFTWARE) | \
(1UL << SOCK_TIMESTAMPING_SOFTWARE) | \
(1UL << SOCK_TIMESTAMPING_RAW_HARDWARE) | \
(1UL << SOCK_TIMESTAMPING_SYS_HARDWARE))
if (sk->sk_flags & FLAGS_TS_OR_DROPS)
__sock_recv_ts_and_drops(msg, sk, skb);
else
sk->sk_stamp = skb->tstamp;
}
/**
* sock_tx_timestamp - checks whether the outgoing packet is to be time stamped
* @sk: socket sending this packet
* @tx_flags: filled with instructions for time stamping
*
* Currently only depends on SOCK_TIMESTAMPING* flags. Returns error code if
* parameters are invalid.
*/
extern int sock_tx_timestamp(struct sock *sk, __u8 *tx_flags);
/**
* 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.
*/
#ifdef CONFIG_NET_DMA
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)
__kfree_skb(skb);
else
__skb_queue_tail(&sk->sk_async_wait_queue, skb);
}
#else
static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb, int copied_early)
{
__skb_unlink(skb, &sk->sk_receive_queue);
__kfree_skb(skb);
}
#endif
static inline
struct net *sock_net(const struct sock *sk)
{
return read_pnet(&sk->sk_net);
}
static inline
void sock_net_set(struct sock *sk, struct net *net)
{
write_pnet(&sk->sk_net, net);
}
/*
* Kernel sockets, f.e. rtnl or icmp_socket, are a part of a namespace.
* They should not hold a reference to a namespace in order to allow
* to stop it.
* Sockets after sk_change_net should be released using sk_release_kernel
*/
static inline void sk_change_net(struct sock *sk, struct net *net)
{
put_net(sock_net(sk));
sock_net_set(sk, hold_net(net));
}
static inline struct sock *skb_steal_sock(struct sk_buff *skb)
{
if (unlikely(skb->sk)) {
struct sock *sk = skb->sk;
skb->destructor = NULL;
skb->sk = NULL;
return sk;
}
return NULL;
}
extern void sock_enable_timestamp(struct sock *sk, int flag);
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)
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 */
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