STRUCT SOCK(9) Linux Networking STRUCT SOCK(9)NAMEstruct_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_copy_start __sk_common.skc_hash
#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_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
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_rcvbuf;
socket_lock_t sk_lock;
struct sk_backlog;
wait_queue_head_t * sk_sleep;
struct dst_entry * sk_dst_cache;
#ifdef CONFIG_XFRM
struct xfrm_policy * sk_policy[2];
#endif
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;
#ifdef CONFIG_NET_DMA
struct sk_buff_head sk_async_wait_queue;
#endif
int sk_wmem_queued;
int sk_forward_alloc;
gfp_t sk_allocation;
int sk_route_caps;
int sk_gso_type;
unsigned int sk_gso_max_size;
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;
int sk_err_soft;
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;
#ifdef CONFIG_SECURITY
void * sk_security;
#endif
__u32 sk_mark;
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_shutdown
mask of SEND_SHUTDOWN and/or RCV_SHUTDOWN
sk_no_check
SO_NO_CHECK setting, wether 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_rcvbuf
size of receive buffer in bytes
sk_lock
synchronizer
sk_backlog
always used with the per-socket spinlock held
sk_sleep
sock wait queue
sk_dst_cache
destination cache
sk_policy[2]
flow policy
sk_dst_lock
destination cache lock
sk_rmem_alloc
receive queue bytes committed
sk_wmem_alloc
transmit queue bytes committed
sk_omem_alloc
"o“ is ”option“ or ”other"
sk_sndbuf
size of send buffer in bytes
sk_receive_queue
incoming packets
sk_write_queue
Packet sending queue
sk_async_wait_queue
DMA copied packets
sk_wmem_queued
persistent queue size
sk_forward_alloc
space allocated forward
sk_allocation
allocation mode
sk_route_caps
route capabilities (e.g. NETIF_F_TSO)
sk_gso_type
GSO type (e.g. SKB_GSO_TCPV4)
sk_gso_max_size
Maximum GSO segment size to build
sk_rcvlowat
SO_RCVLOWAT setting
sk_flags
SO_LINGER (l_onoff), SO_BROADCAST, SO_KEEPALIVE, SO_OOBINLINE
settings, SO_TIMESTAMPING settings
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_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_peercred
SO_PEERCRED 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_send_head
front of stuff to transmit
sk_sndmsg_off
cached offset for sendmsg
sk_write_pending
a write to stream socket waits to start
sk_security
used by security modules
sk_mark
generic packet mark
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
COPYRIGHTKernel Hackers Manual 2.6. November 2013 STRUCT SOCK(9)
