NAME

       tcpconnect.bt - Trace TCP active connections (connect()). Uses Linux bpftrace/eBPF

SYNOPSIS

       tcpconnect.bt

DESCRIPTION

       This tool traces active TCP connections (eg, via a connect() syscall; accept() are passive
       connections). This can be useful for general troubleshooting to see what  connections  are
       initiated by the local server.

       All connection attempts are traced, even if they ultimately fail.

       This  works  by  tracing  the kernel tcp_v4_connect() and tcp_v6_connect() functions using
       dynamic tracing, and will need updating to match any changes to these functions.

       Since this uses BPF, only the root user can use this tool.

REQUIREMENTS

       CONFIG_BPF and bpftrace.

EXAMPLES

       Trace all active TCP connections:
              # tcpconnect.bt

       FIELDS

       TIME(s)
              Time of the call, in HH:MM:SS format.

       PID    Process ID

       COMM   Process name

       SADDR  Source IP address.

       SPORT  Source port.

       DADDR  Destination IP address.

       DPORT  Destination port

OVERHEAD

       This traces the kernel tcp_v[46]_connect functions and prints output for  each  event.  As
       the rate of this is generally expected to be low (< 1000/s), the overhead is also expected
       to be negligible. If you have an application that is calling a high rate  of  connects()s,
       such as a proxy server, then test and understand this overhead before use.

SOURCE

       This is from bpftrace

              https://github.com/iovisor/bpftrace

       Also  look  in  the  bpftrace  distribution  for a companion _examples.txt file containing
       example usage, output, and commentary for this tool.

       This is a bpftrace version of the bcc tool of the same name. The bcc tool may provide more
       options and customizations.

              https://github.com/iovisor/bcc

OS

       Linux

STABILITY

       Unstable - in development.

AUTHOR

       Brendan Gregg, adapted for bpftrace by Dale Hamel

SEE ALSO

       tcpaccept(8), funccount(8), tcpdump(8)