#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @lint-avoid-python-3-compatibility-imports
#
# tcpstates Trace the TCP session state changes with durations.
# For Linux, uses BCC, BPF. Embedded C.
#
# USAGE: tcpstates [-h] [-C] [-S] [interval [count]] [-4 | -6]
#
# This uses the sock:inet_sock_set_state tracepoint, added to Linux 4.16.
# Linux 4.16 also adds more state transitions so that they can be traced.
#
# Copyright 2018 Netflix, Inc.
# Licensed under the Apache License, Version 2.0 (the "License")
#
# 20-Mar-2018 Brendan Gregg Created this.
from __future__ import print_function
from bcc import BPF
import argparse
from socket import inet_ntop, AF_INET, AF_INET6
from time import strftime, time
from os import getuid
# arguments
examples = """examples:
./tcpstates # trace all TCP state changes
./tcpstates -t # include timestamp column
./tcpstates -T # include time column (HH:MM:SS)
./tcpstates -w # wider columns (fit IPv6)
./tcpstates -stT # csv output, with times & timestamps
./tcpstates -Y # log events to the systemd journal
./tcpstates -L 80 # only trace local port 80
./tcpstates -L 80,81 # only trace local ports 80 and 81
./tcpstates -D 80 # only trace remote port 80
./tcpstates -4 # trace IPv4 family only
./tcpstates -6 # trace IPv6 family only
"""
parser = argparse.ArgumentParser(
description="Trace TCP session state changes and durations",
formatter_class=argparse.RawDescriptionHelpFormatter,
epilog=examples)
parser.add_argument("-T", "--time", action="store_true",
help="include time column on output (HH:MM:SS)")
parser.add_argument("-t", "--timestamp", action="store_true",
help="include timestamp on output (seconds)")
parser.add_argument("-w", "--wide", action="store_true",
help="wide column output (fits IPv6 addresses)")
parser.add_argument("-s", "--csv", action="store_true",
help="comma separated values output")
parser.add_argument("-L", "--localport",
help="comma-separated list of local ports to trace.")
parser.add_argument("-D", "--remoteport",
help="comma-separated list of remote ports to trace.")
parser.add_argument("--ebpf", action="store_true",
help=argparse.SUPPRESS)
parser.add_argument("-Y", "--journal", action="store_true",
help="log session state changes to the systemd journal")
group = parser.add_mutually_exclusive_group()
group.add_argument("-4", "--ipv4", action="store_true",
help="trace IPv4 family only")
group.add_argument("-6", "--ipv6", action="store_true",
help="trace IPv6 family only")
args = parser.parse_args()
debug = 0
# define BPF program
bpf_header = """
#include <uapi/linux/ptrace.h>
#include <linux/tcp.h>
#include <net/sock.h>
#include <bcc/proto.h>
BPF_HASH(last, struct sock *, u64);
// separate data structs for ipv4 and ipv6
struct ipv4_data_t {
u64 ts_us;
u64 skaddr;
u32 saddr[1];
u32 daddr[1];
u64 span_us;
u32 pid;
u16 lport;
u16 dport;
int oldstate;
int newstate;
char task[TASK_COMM_LEN];
};
BPF_PERF_OUTPUT(ipv4_events);
struct ipv6_data_t {
u64 ts_us;
u64 skaddr;
u32 saddr[4];
u32 daddr[4];
u64 span_us;
u32 pid;
u16 lport;
u16 dport;
int oldstate;
int newstate;
char task[TASK_COMM_LEN];
};
BPF_PERF_OUTPUT(ipv6_events);
"""
bpf_text_tracepoint = """
TRACEPOINT_PROBE(sock, inet_sock_set_state)
{
if (args->protocol != IPPROTO_TCP)
return 0;
u32 pid = bpf_get_current_pid_tgid() >> 32;
// sk is used as a UUID
struct sock *sk = (struct sock *)args->skaddr;
// lport is either used in a filter here, or later
u16 lport = args->sport;
FILTER_LPORT
// dport is either used in a filter here, or later
u16 dport = args->dport;
FILTER_DPORT
// calculate delta
u64 *tsp, delta_us;
tsp = last.lookup(&sk);
if (tsp == 0)
delta_us = 0;
else
delta_us = (bpf_ktime_get_ns() - *tsp) / 1000;
u16 family = args->family;
FILTER_FAMILY
// workaround to avoid llvm optimization which will cause context ptr args modified
int tcp_newstate = args->newstate;
if (args->family == AF_INET) {
struct ipv4_data_t data4 = {
.span_us = delta_us,
.oldstate = args->oldstate,
.newstate = args->newstate };
data4.skaddr = (u64)args->skaddr;
data4.ts_us = bpf_ktime_get_ns() / 1000;
__builtin_memcpy(&data4.saddr, args->saddr, sizeof(data4.saddr));
__builtin_memcpy(&data4.daddr, args->daddr, sizeof(data4.daddr));
data4.lport = lport;
data4.dport = dport;
data4.pid = pid;
bpf_get_current_comm(&data4.task, sizeof(data4.task));
ipv4_events.perf_submit(args, &data4, sizeof(data4));
} else /* 6 */ {
struct ipv6_data_t data6 = {
.span_us = delta_us,
.oldstate = args->oldstate,
.newstate = args->newstate };
data6.skaddr = (u64)args->skaddr;
data6.ts_us = bpf_ktime_get_ns() / 1000;
__builtin_memcpy(&data6.saddr, args->saddr_v6, sizeof(data6.saddr));
__builtin_memcpy(&data6.daddr, args->daddr_v6, sizeof(data6.daddr));
data6.lport = lport;
data6.dport = dport;
data6.pid = pid;
bpf_get_current_comm(&data6.task, sizeof(data6.task));
ipv6_events.perf_submit(args, &data6, sizeof(data6));
}
if (tcp_newstate == TCP_CLOSE) {
last.delete(&sk);
} else {
u64 ts = bpf_ktime_get_ns();
last.update(&sk, &ts);
}
return 0;
}
"""
bpf_text_kprobe = """
int kprobe__tcp_set_state(struct pt_regs *ctx, struct sock *sk, int state)
{
u32 pid = bpf_get_current_pid_tgid() >> 32;
// sk is used as a UUID
// lport is either used in a filter here, or later
u16 lport = sk->__sk_common.skc_num;
FILTER_LPORT
// dport is either used in a filter here, or later
u16 dport = sk->__sk_common.skc_dport;
dport = ntohs(dport);
FILTER_DPORT
// calculate delta
u64 *tsp, delta_us;
tsp = last.lookup(&sk);
if (tsp == 0)
delta_us = 0;
else
delta_us = (bpf_ktime_get_ns() - *tsp) / 1000;
u16 family = sk->__sk_common.skc_family;
FILTER_FAMILY
if (family == AF_INET) {
struct ipv4_data_t data4 = {
.span_us = delta_us,
.oldstate = sk->__sk_common.skc_state,
.newstate = state };
data4.skaddr = (u64)sk;
data4.ts_us = bpf_ktime_get_ns() / 1000;
data4.saddr = sk->__sk_common.skc_rcv_saddr;
data4.daddr = sk->__sk_common.skc_daddr;
data4.lport = lport;
data4.dport = dport;
data4.pid = pid;
bpf_get_current_comm(&data4.task, sizeof(data4.task));
ipv4_events.perf_submit(ctx, &data4, sizeof(data4));
} else /* 6 */ {
struct ipv6_data_t data6 = {
.span_us = delta_us,
.oldstate = sk->__sk_common.skc_state,
.newstate = state };
data6.skaddr = (u64)sk;
data6.ts_us = bpf_ktime_get_ns() / 1000;
bpf_probe_read_kernel(&data6.saddr, sizeof(data6.saddr),
sk->__sk_common.skc_v6_rcv_saddr.in6_u.u6_addr32);
bpf_probe_read_kernel(&data6.daddr, sizeof(data6.daddr),
sk->__sk_common.skc_v6_daddr.in6_u.u6_addr32);
data6.lport = lport;
data6.dport = dport;
data6.pid = pid;
bpf_get_current_comm(&data6.task, sizeof(data6.task));
ipv6_events.perf_submit(ctx, &data6, sizeof(data6));
}
if (state == TCP_CLOSE) {
last.delete(&sk);
} else {
u64 ts = bpf_ktime_get_ns();
last.update(&sk, &ts);
}
return 0;
};
"""
bpf_text = bpf_header
if BPF.tracepoint_exists("sock", "inet_sock_set_state"):
bpf_text += bpf_text_tracepoint
else:
bpf_text += bpf_text_kprobe
# code substitutions
if args.remoteport:
dports = [int(dport) for dport in args.remoteport.split(',')]
dports_if = ' && '.join(['dport != %d' % dport for dport in dports])
bpf_text = bpf_text.replace('FILTER_DPORT',
'if (%s) { last.delete(&sk); return 0; }' % dports_if)
if args.localport:
lports = [int(lport) for lport in args.localport.split(',')]
lports_if = ' && '.join(['lport != %d' % lport for lport in lports])
bpf_text = bpf_text.replace('FILTER_LPORT',
'if (%s) { last.delete(&sk); return 0; }' % lports_if)
if args.ipv4:
bpf_text = bpf_text.replace('FILTER_FAMILY',
'if (family != AF_INET) { return 0; }')
elif args.ipv6:
bpf_text = bpf_text.replace('FILTER_FAMILY',
'if (family != AF_INET6) { return 0; }')
bpf_text = bpf_text.replace('FILTER_FAMILY', '')
bpf_text = bpf_text.replace('FILTER_DPORT', '')
bpf_text = bpf_text.replace('FILTER_LPORT', '')
if debug or args.ebpf:
print(bpf_text)
if args.ebpf:
exit()
#
# Setup output formats
#
# Don't change the default output (next 2 lines): this fits in 80 chars. I
# know it doesn't have NS or UIDs etc. I know. If you really, really, really
# need to add columns, columns that solve real actual problems, I'd start by
# adding an extended mode (-x) to included those columns.
#
header_string = "%-16s %-5s %-10.10s %s%-15s %-5s %-15s %-5s %-11s -> %-11s %s"
format_string = ("%-16x %-5d %-10.10s %s%-15s %-5d %-15s %-5d %-11s " +
"-> %-11s %.3f")
if args.wide:
header_string = ("%-16s %-5s %-16.16s %-2s %-39s %-5s %-39s %-5s %-11s " +
"-> %-11s %s")
format_string = ("%-16x %-5d %-16.16s %-2s %-39s %-5s %-39s %-5d %-11s " +
"-> %-11s %.3f")
if args.csv:
header_string = "%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s"
format_string = "%x,%d,%s,%s,%s,%s,%s,%d,%s,%s,%.3f"
if args.journal:
try:
from systemd import journal
except ImportError:
print("ERROR: Journal logging requires the systemd.journal module")
exit(1)
def tcpstate2str(state):
# from include/net/tcp_states.h:
tcpstate = {
1: "ESTABLISHED",
2: "SYN_SENT",
3: "SYN_RECV",
4: "FIN_WAIT1",
5: "FIN_WAIT2",
6: "TIME_WAIT",
7: "CLOSE",
8: "CLOSE_WAIT",
9: "LAST_ACK",
10: "LISTEN",
11: "CLOSING",
12: "NEW_SYN_RECV",
}
if state in tcpstate:
return tcpstate[state]
else:
return str(state)
def journal_fields(event, addr_family):
addr_pfx = 'IPV4'
if addr_family == AF_INET6:
addr_pfx = 'IPV6'
fields = {
# Standard fields described in systemd.journal-fields(7). journal.send
# will fill in CODE_LINE, CODE_FILE, and CODE_FUNC for us. If we're
# root and specify OBJECT_PID, systemd-journald will add other OBJECT_*
# fields for us.
'SYSLOG_IDENTIFIER': 'tcpstates',
'PRIORITY': 5,
'_SOURCE_REALTIME_TIMESTAMP': time() * 1000000,
'OBJECT_PID': str(event.pid),
'OBJECT_COMM': event.task.decode('utf-8', 'replace'),
# Custom fields, aka "stuff we sort of made up".
'OBJECT_' + addr_pfx + '_SOURCE_ADDRESS': inet_ntop(addr_family, event.saddr),
'OBJECT_TCP_SOURCE_PORT': str(event.lport),
'OBJECT_' + addr_pfx + '_DESTINATION_ADDRESS': inet_ntop(addr_family, event.daddr),
'OBJECT_TCP_DESTINATION_PORT': str(event.dport),
'OBJECT_TCP_OLD_STATE': tcpstate2str(event.oldstate),
'OBJECT_TCP_NEW_STATE': tcpstate2str(event.newstate),
'OBJECT_TCP_SPAN_TIME': str(event.span_us)
}
msg_format_string = (u"%(OBJECT_COMM)s " +
u"%(OBJECT_" + addr_pfx + "_SOURCE_ADDRESS)s " +
u"%(OBJECT_TCP_SOURCE_PORT)s → " +
u"%(OBJECT_" + addr_pfx + "_DESTINATION_ADDRESS)s " +
u"%(OBJECT_TCP_DESTINATION_PORT)s " +
u"%(OBJECT_TCP_OLD_STATE)s → %(OBJECT_TCP_NEW_STATE)s")
fields['MESSAGE'] = msg_format_string % (fields)
if getuid() == 0:
del fields['OBJECT_COMM'] # Handled by systemd-journald
return fields
# process event
def print_event(event, addr_family):
global start_ts
if args.time:
if args.csv:
print("%s," % strftime("%H:%M:%S"), end="")
else:
print("%-8s " % strftime("%H:%M:%S"), end="")
if args.timestamp:
if start_ts == 0:
start_ts = event.ts_us
delta_s = (float(event.ts_us) - start_ts) / 1000000
if args.csv:
print("%.6f," % delta_s, end="")
else:
print("%-9.6f " % delta_s, end="")
if addr_family == AF_INET:
version = "4"
else:
version = "6"
print(format_string % (event.skaddr, event.pid, event.task.decode('utf-8', 'replace'),
version if args.wide or args.csv else "",
inet_ntop(addr_family, event.saddr), event.lport,
inet_ntop(addr_family, event.daddr), event.dport,
tcpstate2str(event.oldstate), tcpstate2str(event.newstate),
float(event.span_us) / 1000))
if args.journal:
journal.send(**journal_fields(event, addr_family))
def print_ipv4_event(cpu, data, size):
event = b["ipv4_events"].event(data)
print_event(event, AF_INET)
def print_ipv6_event(cpu, data, size):
event = b["ipv6_events"].event(data)
print_event(event, AF_INET6)
# initialize BPF
b = BPF(text=bpf_text)
# header
if args.time:
if args.csv:
print("%s," % ("TIME"), end="")
else:
print("%-8s " % ("TIME"), end="")
if args.timestamp:
if args.csv:
print("%s," % ("TIME(s)"), end="")
else:
print("%-9s " % ("TIME(s)"), end="")
print(header_string % ("SKADDR", "C-PID", "C-COMM",
"IP" if args.wide or args.csv else "",
"LADDR", "LPORT", "RADDR", "RPORT",
"OLDSTATE", "NEWSTATE", "MS"))
start_ts = 0
# read events
b["ipv4_events"].open_perf_buffer(print_ipv4_event, page_cnt=64)
b["ipv6_events"].open_perf_buffer(print_ipv6_event, page_cnt=64)
while 1:
try:
b.perf_buffer_poll()
except KeyboardInterrupt:
exit()
