| Demonstrations of tcpconnect, the Linux eBPF/bcc version. |
| |
| |
| This tool traces the kernel function performing active TCP connections |
| (eg, via a connect() syscall; accept() are passive connections). Some example |
| output (IP addresses changed to protect the innocent): |
| |
| # ./tcpconnect |
| PID COMM IP SADDR DADDR DPORT |
| 1479 telnet 4 127.0.0.1 127.0.0.1 23 |
| 1469 curl 4 10.201.219.236 54.245.105.25 80 |
| 1469 curl 4 10.201.219.236 54.67.101.145 80 |
| 1991 telnet 6 ::1 ::1 23 |
| 2015 ssh 6 fe80::2000:bff:fe82:3ac fe80::2000:bff:fe82:3ac 22 |
| |
| This output shows four connections, one from a "telnet" process, two from |
| "curl", and one from "ssh". The output details shows the IP version, source |
| address, destination address, and destination port. This traces attempted |
| connections: these may have failed. |
| |
| The overhead of this tool should be negligible, since it is only tracing the |
| kernel functions performing connect. It is not tracing every packet and then |
| filtering. |
| |
| |
| The -t option prints a timestamp column: |
| |
| # ./tcpconnect -t |
| TIME(s) PID COMM IP SADDR DADDR DPORT |
| 31.871 2482 local_agent 4 10.103.219.236 10.251.148.38 7001 |
| 31.874 2482 local_agent 4 10.103.219.236 10.101.3.132 7001 |
| 31.878 2482 local_agent 4 10.103.219.236 10.171.133.98 7101 |
| 90.917 2482 local_agent 4 10.103.219.236 10.251.148.38 7001 |
| 90.928 2482 local_agent 4 10.103.219.236 10.102.64.230 7001 |
| 90.938 2482 local_agent 4 10.103.219.236 10.115.167.169 7101 |
| |
| The output shows some periodic connections (or attempts) from a "local_agent" |
| process to various other addresses. A few connections occur every minute. |
| |
| |
| The -U option prints a UID column: |
| |
| # ./tcpconnect -U |
| UID PID COMM IP SADDR DADDR DPORT |
| 0 31333 telnet 6 ::1 ::1 23 |
| 0 31333 telnet 4 127.0.0.1 127.0.0.1 23 |
| 1000 31322 curl 4 127.0.0.1 127.0.0.1 80 |
| 1000 31322 curl 6 ::1 ::1 80 |
| |
| |
| The -u option filtering UID: |
| |
| # ./tcpconnect -Uu 1000 |
| UID PID COMM IP SADDR DADDR DPORT |
| 1000 31338 telnet 6 ::1 ::1 23 |
| 1000 31338 telnet 4 127.0.0.1 127.0.0.1 23 |
| |
| To spot heavy outbound connections quickly one can use the -c flag. It will |
| count all active connections per source ip and destination ip/port. |
| |
| # ./tcpconnect.py -c |
| Tracing connect ... Hit Ctrl-C to end |
| ^C |
| LADDR RADDR RPORT CONNECTS |
| 192.168.10.50 172.217.21.194 443 70 |
| 192.168.10.50 172.213.11.195 443 34 |
| 192.168.10.50 172.212.22.194 443 21 |
| [...] |
| |
| |
| The --cgroupmap option filters based on a cgroup set. It is meant to be used |
| with an externally created map. |
| |
| # ./tcpconnect --cgroupmap /sys/fs/bpf/test01 |
| |
| For more details, see docs/filtering_by_cgroups.md |
| |
| |
| USAGE message: |
| |
| # ./tcpconnect -h |
| usage: tcpconnect.py [-h] [-t] [-p PID] [-P PORT] [-U] [-u UID] [-c] |
| [--cgroupmap CGROUPMAP] |
| |
| Trace TCP connects |
| |
| optional arguments: |
| -h, --help show this help message and exit |
| -t, --timestamp include timestamp on output |
| -p PID, --pid PID trace this PID only |
| -P PORT, --port PORT comma-separated list of destination ports to trace. |
| -U, --print-uid include UID on output |
| -u UID, --uid UID trace this UID only |
| -c, --count count connects per src ip and dest ip/port |
| --cgroupmap CGROUPMAP |
| trace cgroups in this BPF map only |
| |
| examples: |
| ./tcpconnect # trace all TCP connect()s |
| ./tcpconnect -t # include timestamps |
| ./tcpconnect -p 181 # only trace PID 181 |
| ./tcpconnect -P 80 # only trace port 80 |
| ./tcpconnect -P 80,81 # only trace port 80 and 81 |
| ./tcpconnect -U # include UID |
| ./tcpconnect -u 1000 # only trace UID 1000 |
| ./tcpconnect -c # count connects per src ip and dest ip/port |
| ./tcpconnect --cgroupmap ./mappath # only trace cgroups in this BPF map |
