centos man page for struct_sock

STRUCT 
SOCK(9)							 Linux Networking						    STRUCT SOCK(9)

NAME
       struct_sock - network layer representation of sockets

SYNOPSIS
       struct sock {
	 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_portpair	__sk_common.skc_portpair
       #define sk_num		__sk_common.skc_num
       #define sk_dport 	__sk_common.skc_dport
       #define sk_addrpair	__sk_common.skc_addrpair
       #define sk_daddr 	__sk_common.skc_daddr
       #define sk_rcv_saddr	     __sk_common.skc_rcv_saddr
       #define sk_family	__sk_common.skc_family
       #define sk_state 	__sk_common.skc_state
       #define sk_reuse 	__sk_common.skc_reuse
       #define sk_reuseport	     __sk_common.skc_reuseport
       #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
       #define sk_v6_daddr	__sk_common.skc_v6_daddr
       #define sk_v6_rcv_saddr	__sk_common.skc_v6_rcv_saddr
	 socket_lock_t sk_lock;
	 struct sk_buff_head sk_receive_queue;
	 struct sk_backlog;
       #define sk_rmem_alloc sk_backlog.rmem_alloc
	 int sk_forward_alloc;
       #ifdef CONFIG_RPS
	 __u32 sk_rxhash;
       #endif
       #ifdef CONFIG_NET_RX_BUSY_POLL
	 unsigned int sk_napi_id;
	 unsigned int sk_ll_usec;
       #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_rx_dst;
	 struct dst_entry __rcu * 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;
	 unsigned int sk_shutdown:2;
	 unsigned int sk_no_check:2;
	 unsigned int sk_userlocks:4;
	 unsigned int sk_protocol:8;
	 unsigned int sk_type:16;
	 int sk_wmem_queued;
	 gfp_t sk_allocation;
	 u32 sk_pacing_rate;
	 netdev_features_t sk_route_caps;
	 netdev_features_t sk_route_nocaps;
	 int sk_gso_type;
	 unsigned int sk_gso_max_size;
	 u16 sk_gso_max_segs;
	 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;
	 int sk_err_soft;
	 unsigned short sk_ack_backlog;
	 unsigned short sk_max_ack_backlog;
	 __u32 sk_priority;
       #if IS_ENABLED(CONFIG_NETPRIO_CGROUP)
	 __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_frag sk_frag;
	 struct sk_buff * sk_send_head;
	 __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);
       };

MEMBERS
       __sk_common
	   shared layout with inet_timewait_sock

       sk_lock
	   synchronizer

       sk_receive_queue
	   incoming packets

       sk_backlog
	   always used with the per-socket spinlock held

       sk_forward_alloc
	   space allocated forward

       sk_rxhash
	   flow hash received from netif layer

       sk_napi_id
	   id of the last napi context to receive data for sk

       sk_ll_usec
	   usecs to busypoll when there is no data

       sk_drops
	   raw/udp drops counter

       sk_rcvbuf
	   size of receive buffer in bytes

       sk_filter
	   socket filtering instructions

       sk_wq
	   sock wait queue and async head

       sk_async_wait_queue
	   DMA copied packets

       sk_policy[2]
	   flow policy

       sk_flags
	   SO_LINGER (l_onoff), SO_BROADCAST, SO_KEEPALIVE, SO_OOBINLINE settings, SO_TIMESTAMPING settings

       sk_rx_dst
	   receive input route used by early tcp demux

       sk_dst_cache
	   destination cache

       sk_dst_lock
	   destination cache lock

       sk_wmem_alloc
	   transmit queue bytes committed

       sk_omem_alloc
	   "o" is "option" or "other"

       sk_sndbuf
	   size of send buffer in bytes

       sk_write_queue
	   Packet sending queue

       sk_shutdown
	   mask of SEND_SHUTDOWN and/or RCV_SHUTDOWN

       sk_no_check
	   SO_NO_CHECK setting, whether or not checkup packets

       sk_userlocks
	   SO_SNDBUF and SO_RCVBUF settings

       sk_protocol
	   which protocol this socket belongs in this network family

       sk_type
	   socket type (SOCK_STREAM, etc)

       sk_wmem_queued
	   persistent queue size

       sk_allocation
	   allocation mode

       sk_pacing_rate
	   Pacing rate (if supported by transport/packet scheduler)

       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_gso_max_segs
	   Maximum number of GSO segments

       sk_rcvlowat
	   SO_RCVLOWAT setting

       sk_lingertime
	   SO_LINGER l_linger setting

       sk_error_queue
	   rarely used

       sk_prot_creator
	   sk_prot of original sock creator (see ipv6_setsockopt, IPV6_ADDRFORM for instance)

       sk_callback_lock
	   used with the callbacks in the end of this struct

       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_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_peer_pid
	   struct pid for this socket's peer

       sk_peer_cred
	   SO_PEERCRED setting

       sk_rcvtimeo
	   SO_RCVTIMEO setting

       sk_sndtimeo
	   SO_SNDTIMEO setting

       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_frag
	   cached page frag

       sk_send_head
	   front of stuff to transmit

       sk_peek_off
	   current peek_offset value

       sk_write_pending
	   a write to stream socket waits to start

       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_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

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014							    STRUCT SOCK(9)