#!/usr/bin/python # @lint-avoid-python-3-compatibility-imports # # tcpconnect Trace TCP connect()s. # For Linux, uses BCC, eBPF. Embedded C. # # USAGE: tcpconnect [-h] [-t] [-p PID] # # All connection attempts are traced, even if they ultimately fail. # # 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: ./tcpconnect # trace all TCP connect()s ./tcpconnect -t # include timestamps ./tcpconnect -p 181 # only trace PID 181 """ parser = argparse.ArgumentParser( description="Trace TCP 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 #include #include BPF_HASH(currsock, u32, struct sock *); int trace_connect_entry(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; }; static int trace_connect_return(struct pt_regs *ctx, short ipver) { int ret = PT_REGS_RC(ctx); 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; dport = skp->__sk_common.skc_dport; if (ipver == 4) { saddr = skp->__sk_common.skc_rcv_saddr; daddr = skp->__sk_common.skc_daddr; // output bpf_trace_printk("4 %x %x %d\\n", saddr, daddr, ntohs(dport)); } else /* 6 */ { // just grab the last 4 bytes for now bpf_probe_read(&saddr, sizeof(saddr), &skp->__sk_common.skc_v6_rcv_saddr.in6_u.u6_addr32[3]); bpf_probe_read(&daddr, sizeof(daddr), &skp->__sk_common.skc_v6_daddr.in6_u.u6_addr32[3]); // output and flip byte order of addresses bpf_trace_printk("6 %x %x %d\\n", bpf_ntohl(saddr), bpf_ntohl(daddr), ntohs(dport)); } currsock.delete(&pid); return 0; } int trace_connect_v4_return(struct pt_regs *ctx) { return trace_connect_return(ctx, 4); } int trace_connect_v6_return(struct pt_regs *ctx) { return trace_connect_return(ctx, 6); } """ # 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) b.attach_kprobe(event="tcp_v4_connect", fn_name="trace_connect_entry") b.attach_kprobe(event="tcp_v6_connect", fn_name="trace_connect_entry") b.attach_kretprobe(event="tcp_v4_connect", fn_name="trace_connect_v4_return") b.attach_kretprobe(event="tcp_v6_connect", fn_name="trace_connect_v6_return") # header if args.timestamp: print("%-9s" % ("TIME(s)"), end="") print("%-6s %-12s %-2s %-16s %-16s %-4s" % ("PID", "COMM", "IP", "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() (ip_s, 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 %-2s %-16s %-16s %-4s" % (pid, task, ip_s, inet_ntoa(int(saddr_hs, 16)) if ip_s == "4" else "..." + saddr_hs, inet_ntoa(int(daddr_hs, 16)) if ip_s == "4" else "..." + daddr_hs, dport_s))