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Copy pathtcpaccept.py
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executable file
·202 lines (182 loc) · 5.89 KB
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#!/usr/bin/python
# @lint-avoid-python-3-compatibility-imports
#
# tcpaccept Trace TCP accept()s.
# For Linux, uses BCC, eBPF. Embedded C.
#
# USAGE: tcpaccept [-h] [-t] [-p PID]
#
# This uses dynamic tracing of the kernel inet_csk_accept() socket function
# (from tcp_prot.accept), and will need to be modified to match kernel changes.
#
# IPv4 addresses are printed as dotted quads. For IPv6 addresses, the last four
# bytes are printed after "..."; check for future versions with better IPv6
# support.
#
# Copyright (c) 2015 Brendan Gregg.
# Licensed under the Apache License, Version 2.0 (the "License")
#
# 13-Oct-2015 Brendan Gregg Created this.
# 14-Feb-2016 " " Switch to bpf_perf_output.
from __future__ import print_function
from bcc import BPF
import argparse
import ctypes as ct
# arguments
examples = """examples:
./tcpaccept # trace all TCP accept()s
./tcpaccept -t # include timestamps
./tcpaccept -p 181 # only trace PID 181
"""
parser = argparse.ArgumentParser(
description="Trace TCP accepts",
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>
// 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 ip;
u64 saddr;
u64 daddr;
u64 lport;
char task[TASK_COMM_LEN];
};
BPF_PERF_OUTPUT(ipv4_events);
struct ipv6_data_t {
// XXX: update to transfer full ipv6 addrs
u64 ts_us;
u64 pid;
u64 ip;
u64 saddr;
u64 daddr;
u64 lport;
char task[TASK_COMM_LEN];
};
BPF_PERF_OUTPUT(ipv6_events);
int kretprobe__inet_csk_accept(struct pt_regs *ctx)
{
struct sock *newsk = (struct sock *)ctx->ax;
u32 pid = bpf_get_current_pid_tgid();
if (newsk == NULL)
return 0;
// check this is TCP
u8 protocol = 0;
// workaround for reading the sk_protocol bitfield:
bpf_probe_read(&protocol, 1, (void *)((long)&newsk->sk_wmem_queued) - 3);
if (protocol != IPPROTO_TCP)
return 0;
// pull in details
u16 family = 0, lport = 0;
bpf_probe_read(&family, sizeof(family), &newsk->__sk_common.skc_family);
bpf_probe_read(&lport, sizeof(lport), &newsk->__sk_common.skc_num);
if (family == AF_INET) {
struct ipv4_data_t data4 = {.pid = pid, .ip = 4};
data4.ts_us = bpf_ktime_get_ns() / 1000;
bpf_probe_read(&data4.saddr, sizeof(u32),
&newsk->__sk_common.skc_rcv_saddr);
bpf_probe_read(&data4.daddr, sizeof(u32),
&newsk->__sk_common.skc_daddr);
data4.lport = lport;
bpf_get_current_comm(&data4.task, sizeof(data4.task));
ipv4_events.perf_submit(ctx, &data4, sizeof(data4));
} else if (family == AF_INET6) {
struct ipv6_data_t data6 = {.pid = pid, .ip = 6};
data6.ts_us = bpf_ktime_get_ns() / 1000;
// just grab the last 4 bytes for now
u32 saddr = 0, daddr = 0;
bpf_probe_read(&saddr, sizeof(saddr),
&newsk->__sk_common.skc_v6_rcv_saddr.in6_u.u6_addr32[3]);
bpf_probe_read(&daddr, sizeof(daddr),
&newsk->__sk_common.skc_v6_daddr.in6_u.u6_addr32[3]);
data6.saddr = bpf_ntohl(saddr);
data6.daddr = bpf_ntohl(daddr);
data6.lport = lport;
bpf_get_current_comm(&data6.task, sizeof(data6.task));
ipv6_events.perf_submit(ctx, &data6, sizeof(data6));
}
// else drop
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)
# event data
TASK_COMM_LEN = 16 # linux/sched.h
class Data_ipv4(ct.Structure):
_fields_ = [
("ts_us", ct.c_ulonglong),
("pid", ct.c_ulonglong),
("ip", ct.c_ulonglong),
("saddr", ct.c_ulonglong),
("daddr", ct.c_ulonglong),
("lport", 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),
("ip", ct.c_ulonglong),
("saddr", ct.c_ulonglong),
("daddr", ct.c_ulonglong),
("lport", 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
if args.timestamp:
if start_ts == 0:
start_ts = event.ts_us
print("%-9.3f" % ((event.ts_us - start_ts) / 100000), end="")
print("%-6d %-12.12s %-2d %-16s %-16s %-4d" % (event.pid, event.task,
event.ip, inet_ntoa(event.daddr), inet_ntoa(event.saddr),
event.lport))
def print_ipv6_event(cpu, data, size):
event = ct.cast(data, ct.POINTER(Data_ipv6)).contents
if args.timestamp:
if start_ts == 0:
start_ts = event.ts_us
print("%-9.3f" % ((event.ts_us - start_ts) / 100000), end="")
print("%-6d %-12.12s %-2d ...%-13x ...%-13x %-4d" % (event.pid,
event.task, event.ip, event.daddr, event.saddr, event.lport))
# initialize BPF
b = BPF(text=bpf_text)
# header
if args.timestamp:
print("%-9s" % ("TIME(s)"), end="")
print("%-6s %-12s %-2s %-16s %-16s %-4s" % ("PID", "COMM", "IP", "RADDR",
"LADDR", "LPORT"))
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
# read events
b["ipv4_events"].open_perf_buffer(print_ipv4_event)
b["ipv6_events"].open_perf_buffer(print_ipv6_event)
while 1:
b.kprobe_poll()