tools/tcpv4connect

#!/usr/bin/python
#
# tcpv4connect	Trace TCP IPv4 connect()s.
#		For Linux, uses BCC, eBPF. Embedded C.
#
# USAGE: tcpv4connect [-h] [-t] [-p PID]
#
# Copyright (c) 2015 Brendan Gregg.
# Licensed under the Apache License, Version 2.0 (the "License")
#
# 25-Sep-2015	Brendan Gregg	Created this.

from __future__ import print_function
from bcc import BPF
import argparse

# arguments
examples = """examples:
    ./tcpv4connect           # trace all open() syscalls
    ./tcpv4connect -t        # include timestamps
    ./tcpv4connect -p 181    # only trace PID 181
"""
parser = argparse.ArgumentParser(
	description="Trace TCP IPv4 connects",
	formatter_class=argparse.RawDescriptionHelpFormatter,
	epilog=examples)
parser.add_argument("-t", "--timestamp", action="store_true",
	help="include timestamp on output")
parser.add_argument("-p", "--pid",
	help="trace this PID only")
args = parser.parse_args()
debug = 0

# define BPF program
bpf_text = """
#include <uapi/linux/ptrace.h>
#include <net/sock.h>
#include <bcc/proto.h>

BPF_HASH(currsock, u32, struct sock *);

int kprobe__tcp_v4_connect(struct pt_regs *ctx, struct sock *sk)
{
	u32 pid = bpf_get_current_pid_tgid();
	FILTER

	// stash the sock ptr for lookup on return
	currsock.update(&pid, &sk);

	return 0;
};

int kretprobe__tcp_v4_connect(struct pt_regs *ctx)
{
	int ret = ctx->ax;
	u32 pid = bpf_get_current_pid_tgid();

	struct sock **skpp;
	skpp = currsock.lookup(&pid);
	if (skpp == 0) {
		return 0;	// missed entry
	}

	if (ret != 0) {
		// failed to send SYNC packet, socket __sk_common.{skc_rcv_saddr, ...}
		// may not be populated properly.
		currsock.delete(&pid);
		return 0;
	}

	// pull in details
	struct sock *skp = *skpp;
	u32 saddr = 0, daddr = 0;
	u16 dport = 0;
	bpf_probe_read(&saddr, sizeof(saddr), &skp->__sk_common.skc_rcv_saddr);
	bpf_probe_read(&daddr, sizeof(daddr), &skp->__sk_common.skc_daddr);
	bpf_probe_read(&dport, sizeof(dport), &skp->__sk_common.skc_dport);

	// output
	bpf_trace_printk("%x %x %d\\n", saddr, daddr, ntohs(dport));

	currsock.delete(&pid);

	return 0;
}
"""

# code substitutions
if args.pid:
	bpf_text = bpf_text.replace('FILTER',
	    'if (pid != %s) { return 0; }' % args.pid)
else:
	bpf_text = bpf_text.replace('FILTER', '')
if debug:
	print(bpf_text)

# initialize BPF
b = BPF(text=bpf_text)

# header
if args.timestamp:
	print("%-9s" % ("TIME(s)"), end="")
print("%-6s %-12s %-16s %-16s %-4s" % ("PID", "COMM", "SADDR", "DADDR",
    "DPORT"))

start_ts = 0

def inet_ntoa(addr):
	dq = ''
	for i in range(0, 4):
		dq = dq + str(addr & 0xff)
		if (i != 3):
			dq = dq + '.'
		addr = addr >> 8
	return dq

# format output
while 1:
	(task, pid, cpu, flags, ts, msg) = b.trace_fields()
	(saddr_hs, daddr_hs, dport_s) = msg.split(" ")

	if args.timestamp:
		if start_ts == 0:
			start_ts = ts
		print("%-9.3f" % (ts - start_ts), end="")
	print("%-6d %-12.12s %-16s %-16s %-4s" % (pid, task,
	    inet_ntoa(int(saddr_hs, 16)),
	    inet_ntoa(int(daddr_hs, 16)),
	    dport_s))