blob: 6841115e401067905d964efe81530a4aef9cd1c8 [file] [log] [blame]
#!/usr/bin/python
#
# tcpv4connect Trace TCP IPv4 connect()s.
# For Linux, uses BCC, eBPF. Embedded C.
#
# USAGE: tcpv4connect [-h] [-t] [-p PID]
#
# This is provided as a basic example of TCP connection & socket tracing.
#
# All IPv4 connection attempts are traced, even if they ultimately fail.
#
# Copyright (c) 2015 Brendan Gregg.
# Licensed under the Apache License, Version 2.0 (the "License")
#
# 15-Oct-2015 Brendan Gregg Created this.
from __future__ import print_function
from bcc import BPF
# 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();
// 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, may not have populated
// socket __sk_common.{skc_rcv_saddr, ...}
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("trace_tcp4connect %x %x %d\\n", saddr, daddr, ntohs(dport));
currsock.delete(&pid);
return 0;
}
"""
# initialize BPF
b = BPF(text=bpf_text)
# header
print("%-6s %-12s %-16s %-16s %-4s" % ("PID", "COMM", "SADDR", "DADDR",
"DPORT"))
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
# filter and format output
while 1:
# Read messages from kernel pipe
try:
(task, pid, cpu, flags, ts, msg) = b.trace_fields()
(_tag, saddr_hs, daddr_hs, dport_s) = msg.split(" ")
except ValueError:
# Ignore messages from other tracers
continue
# Ignore messages from other tracers
if _tag != "trace_tcp4connect":
continue
print("%-6d %-12.12s %-16s %-16s %-4s" % (pid, task,
inet_ntoa(int(saddr_hs, 16)),
inet_ntoa(int(daddr_hs, 16)),
dport_s))