net: doc: fix compile warning of no format arguments in ifenslave.c
[linux-2.6.git] / Documentation / networking / proc_net_tcp.txt
1 This document describes the interfaces /proc/net/tcp and /proc/net/tcp6.
2 Note that these interfaces are deprecated in favor of tcp_diag.
3
4 These /proc interfaces provide information about currently active TCP 
5 connections, and are implemented by tcp4_seq_show() in net/ipv4/tcp_ipv4.c
6 and tcp6_seq_show() in net/ipv6/tcp_ipv6.c, respectively.
7
8 It will first list all listening TCP sockets, and next list all established
9 TCP connections. A typical entry of /proc/net/tcp would look like this (split 
10 up into 3 parts because of the length of the line):
11
12    46: 010310AC:9C4C 030310AC:1770 01 
13    |      |      |      |      |   |--> connection state
14    |      |      |      |      |------> remote TCP port number
15    |      |      |      |-------------> remote IPv4 address
16    |      |      |--------------------> local TCP port number
17    |      |---------------------------> local IPv4 address
18    |----------------------------------> number of entry
19
20    00000150:00000000 01:00000019 00000000  
21       |        |     |     |       |--> number of unrecovered RTO timeouts
22       |        |     |     |----------> number of jiffies until timer expires
23       |        |     |----------------> timer_active (see below)
24       |        |----------------------> receive-queue
25       |-------------------------------> transmit-queue
26
27    1000        0 54165785 4 cd1e6040 25 4 27 3 -1
28     |          |    |     |    |     |  | |  | |--> slow start size threshold, 
29     |          |    |     |    |     |  | |  |      or -1 if the threshold
30     |          |    |     |    |     |  | |  |      is >= 0xFFFF
31     |          |    |     |    |     |  | |  |----> sending congestion window
32     |          |    |     |    |     |  | |-------> (ack.quick<<1)|ack.pingpong
33     |          |    |     |    |     |  |---------> Predicted tick of soft clock
34     |          |    |     |    |     |              (delayed ACK control data)
35     |          |    |     |    |     |------------> retransmit timeout
36     |          |    |     |    |------------------> location of socket in memory
37     |          |    |     |-----------------------> socket reference count
38     |          |    |-----------------------------> inode
39     |          |----------------------------------> unanswered 0-window probes
40     |---------------------------------------------> uid
41
42 timer_active:
43   0  no timer is pending
44   1  retransmit-timer is pending
45   2  another timer (e.g. delayed ack or keepalive) is pending
46   3  this is a socket in TIME_WAIT state. Not all fields will contain 
47      data (or even exist)
48   4  zero window probe timer is pending