#!/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] [-P PORT [PORT ...]] # # All connection attempts are traced, even if they ultimately fail. # # This uses dynamic tracing of kernel functions, and will need to be updated # to match kernel changes. # # Copyright (c) 2015 Brendan Gregg. # Licensed under the Apache License, Version 2.0 (the "License") # # 25-Sep-2015 Brendan Gregg Created this. # 14-Feb-2016 " " Switch to bpf_perf_output. from __future__ import print_function from bcc import BPF import argparse from socket import inet_ntop, ntohs, AF_INET, AF_INET6 from struct import pack import ctypes as ct # arguments examples = """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 """ 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") parser.add_argument("-P", "--port", help="comma-separated list of destination ports to trace.") parser.add_argument("--ebpf", action="store_true", help=argparse.SUPPRESS) args = parser.parse_args() debug = 0 # define BPF program bpf_text = """ #include #include #include BPF_HASH(currsock, u32, struct sock *); // separate data structs for ipv4 and ipv6 struct ipv4_data_t { // XXX: switch some to u32's when supported u64 ts_us; u64 pid; u64 saddr; u64 daddr; u64 ip; u64 dport; char task[TASK_COMM_LEN]; }; BPF_PERF_OUTPUT(ipv4_events); struct ipv6_data_t { u64 ts_us; u64 pid; unsigned __int128 saddr; unsigned __int128 daddr; u64 ip; u64 dport; char task[TASK_COMM_LEN]; }; BPF_PERF_OUTPUT(ipv6_events); int trace_connect_entry(struct pt_regs *ctx, struct sock *sk) { u32 pid = bpf_get_current_pid_tgid(); FILTER_PID // 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; u16 dport = skp->__sk_common.skc_dport; FILTER_PORT if (ipver == 4) { struct ipv4_data_t data4 = {.pid = pid, .ip = ipver}; data4.ts_us = bpf_ktime_get_ns() / 1000; data4.saddr = skp->__sk_common.skc_rcv_saddr; data4.daddr = skp->__sk_common.skc_daddr; data4.dport = ntohs(dport); bpf_get_current_comm(&data4.task, sizeof(data4.task)); ipv4_events.perf_submit(ctx, &data4, sizeof(data4)); } else /* 6 */ { struct ipv6_data_t data6 = {.pid = pid, .ip = ipver}; data6.ts_us = bpf_ktime_get_ns() / 1000; bpf_probe_read(&data6.saddr, sizeof(data6.saddr), skp->__sk_common.skc_v6_rcv_saddr.in6_u.u6_addr32); bpf_probe_read(&data6.daddr, sizeof(data6.daddr), skp->__sk_common.skc_v6_daddr.in6_u.u6_addr32); data6.dport = ntohs(dport); bpf_get_current_comm(&data6.task, sizeof(data6.task)); ipv6_events.perf_submit(ctx, &data6, sizeof(data6)); } 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_PID', 'if (pid != %s) { return 0; }' % args.pid) if args.port: dports = [int(dport) for dport in args.port.split(',')] dports_if = ' && '.join(['dport != %d' % ntohs(dport) for dport in dports]) bpf_text = bpf_text.replace('FILTER_PORT', 'if (%s) { currsock.delete(&pid); return 0; }' % dports_if) bpf_text = bpf_text.replace('FILTER_PID', '') bpf_text = bpf_text.replace('FILTER_PORT', '') if debug or args.ebpf: print(bpf_text) if args.ebpf: exit() # event data TASK_COMM_LEN = 16 # linux/sched.h class Data_ipv4(ct.Structure): _fields_ = [ ("ts_us", ct.c_ulonglong), ("pid", ct.c_ulonglong), ("saddr", ct.c_ulonglong), ("daddr", ct.c_ulonglong), ("ip", ct.c_ulonglong), ("dport", ct.c_ulonglong), ("task", ct.c_char * TASK_COMM_LEN) ] class Data_ipv6(ct.Structure): _fields_ = [ ("ts_us", ct.c_ulonglong), ("pid", ct.c_ulonglong), ("saddr", (ct.c_ulonglong * 2)), ("daddr", (ct.c_ulonglong * 2)), ("ip", ct.c_ulonglong), ("dport", ct.c_ulonglong), ("task", ct.c_char * TASK_COMM_LEN) ] # process event def print_ipv4_event(cpu, data, size): event = ct.cast(data, ct.POINTER(Data_ipv4)).contents global start_ts if args.timestamp: if start_ts == 0: start_ts = event.ts_us print("%-9.3f" % ((float(event.ts_us) - start_ts) / 1000000), end="") print("%-6d %-12.12s %-2d %-16s %-16s %-4d" % (event.pid, event.task.decode(), event.ip, inet_ntop(AF_INET, pack("I", event.saddr)), inet_ntop(AF_INET, pack("I", event.daddr)), event.dport)) def print_ipv6_event(cpu, data, size): event = ct.cast(data, ct.POINTER(Data_ipv6)).contents global start_ts if args.timestamp: if start_ts == 0: start_ts = event.ts_us print("%-9.3f" % ((float(event.ts_us) - start_ts) / 1000000), end="") print("%-6d %-12.12s %-2d %-16s %-16s %-4d" % (event.pid, event.task.decode(), event.ip, inet_ntop(AF_INET6, event.saddr), inet_ntop(AF_INET6, event.daddr), event.dport)) # 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 # read events b["ipv4_events"].open_perf_buffer(print_ipv4_event) b["ipv6_events"].open_perf_buffer(print_ipv6_event) while 1: b.perf_buffer_poll()