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executable file 240 lines (207 sloc) 6.85 KB
#!/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 <uapi/linux/ptrace.h>
#include <net/sock.h>
#include <bcc/proto.h>
BPF_HASH(currsock, u32, struct sock *);
// separate data structs for ipv4 and ipv6
struct ipv4_data_t {
u64 ts_us;
u32 pid;
u32 saddr;
u32 daddr;
u64 ip;
u16 dport;
char task[TASK_COMM_LEN];
};
BPF_PERF_OUTPUT(ipv4_events);
struct ipv6_data_t {
u64 ts_us;
u32 pid;
unsigned __int128 saddr;
unsigned __int128 daddr;
u64 ip;
u16 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_uint),
("saddr", ct.c_uint),
("daddr", ct.c_uint),
("ip", ct.c_ulonglong),
("dport", ct.c_ushort),
("task", ct.c_char * TASK_COMM_LEN)
]
class Data_ipv6(ct.Structure):
_fields_ = [
("ts_us", ct.c_ulonglong),
("pid", ct.c_uint),
("saddr", (ct.c_ulonglong * 2)),
("daddr", (ct.c_ulonglong * 2)),
("ip", ct.c_ulonglong),
("dport", ct.c_ushort),
("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()