要找个工具来调查下unix域套接字的发送和接受情况，比如说A程序是否送出，B程序是否接收到，他找了tcpdump ,wireshark什么的，貌似都不支持。
这时候还是伟大的systemtap来救助了。 因为所有的socket通讯都是通过socket接口来的，任何family的通讯包括unix域套接都要走的，所以只要截获了socket 读写的几个syscall 就搞定了.
systemtap发行版本提供了个工具socktop， 位于 /usr/share/doc/systemtap/examples/network/socktop, 是个非常方便的工具, 干这个事情最合适了。
socktop源码里面的版权和简单的功能介绍：
# Socktop systemtap script
# Copyright (C) 2006 IBM Corp.
#
# This file is part of systemtap, and is free software. You can
# redistribute it and/or modify it under the terms of the GNU General
# Public License (GPL); either version 2, or (at your option) any
# later version.
###
### socktop – Combination shell/systemtap script to track reads and writes
### on sockets by process. Can be filtered by process IDs and
### names, protocols, protocol families, users and socket type.
###
| $ rpm -i kernel-debuginfo-common-2.6.18-164.el5.x86_64.rpm |
| $ rpm -i kernel-debuginfo-2.6.18-164.el5.x86_64.rpm |
| $ /usr/share/doc/systemtap/examples/network/socktop -h |
| USAGE: socktop [-d] [-i interval] [-N num] [-P protocol]... [-f family]... |
| [-t stype]... [-n pname]... [-p pid]... [-u username]... [-h] |
| -d # print network device traffic (default: off) |
| -i interval # interval in seconds between printing (default: 5) |
| -N num # number of top processes and devices to print (default: 10) |
| -f family # this protocol family only (default: all) |
| -P protocol # this protocol only (default: all) |
| -t stype # this socket type only (default: all) |
| -n pname # this process name only (default: all) |
| -p pid # this process ID only (default: all) |
| -u username # this user only (default: all) |
| -c count # number of iteration |
| -m mod_name # generate instrumentation (but do not run) |
| -h # print this help text |
| LOCAL, INET, INET6, IPX, NETLINK, X25, AX25, ATMPVC, APPLETALK, PACKET |
| TCP, UDP, SCTP, IP, FC, ... (see /etc/protocols for complete list) |
| STREAM, DGRAM, RAW, RDM, SEQPACKET, DCCP, PACKET |
上面的使用写的很明白了，我们要过滤的是unix套接字， 每5秒报告下情况， 还顺手把网络设备的流量打出来。
| $sudo /usr/share/doc/systemtap/examples/network/socktop -f LOCAL -i 5 -d |
| ======================= Thu Mar 31 21:23:03 2011 ======================== |
| ------------------------------- PROCESSES ------------------------------- |
| PID UID #SEND #RECV SEND_KB RECV_KB PROT FAMILY COMMAND |
| 24821 50453 1 0 0 0 IP LOCAL crond |
| 3840 0 0 2 0 0 IP LOCAL syslog-ng |
| -------------------------------- DEVICES -------------------------------- |
| DEV #XMIT #RECV XMIT_KB RECV_KB |
| ========================================================================= |
我们很清楚的看到了，crond在发，syslog-ng在收。
如果你想知道报文的内容的话，可以改改脚本把报文也dump出来。
