Commit | Line | Data |
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1da177e4 | 1 | This document describes the interfaces /proc/net/tcp and /proc/net/tcp6. |
d603d0ab | 2 | Note that these interfaces are deprecated in favor of tcp_diag. |
1da177e4 LT |
3 | |
4 | These /proc interfaces provide information about currently active TCP | |
d603d0ab JD |
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. | |
1da177e4 LT |
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, | |
fa00e7e1 | 29 | | | | | | | | | | or -1 if the threshold |
1da177e4 LT |
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 |