tools/tcpstates.py - platform/external/bcc - Git at Google

 #!/usr/bin/python
 # @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]]
 #
 # 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 struct import pack
 import ctypes as ct
 from time import strftime

 # 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 colums (fit IPv6)
     ./tcpstates -stT      # csv output, with times & timestamps
     ./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
 """
 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)
 args = parser.parse_args()
 debug = 0

 # define BPF program
 bpf_text = """
 #include <uapi/linux/ptrace.h>
 #define KBUILD_MODNAME "foo"
 #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;
     u32 daddr;
     u64 span_us;
     u32 pid;
     u32 ports;
     u32 oldstate;
     u32 newstate;
     char task[TASK_COMM_LEN];
 };
 BPF_PERF_OUTPUT(ipv4_events);

 struct ipv6_data_t {
     u64 ts_us;
     u64 skaddr;
     unsigned __int128 saddr;
     unsigned __int128 daddr;
     u64 span_us;
     u32 pid;
     u32 ports;
     u32 oldstate;
     u32 newstate;
     char task[TASK_COMM_LEN];
 };
 BPF_PERF_OUTPUT(ipv6_events);

 struct id_t {
     u32 pid;
     char task[TASK_COMM_LEN];
 };

 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;

     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));
         // a workaround until data4 compiles with separate lport/dport
         data4.ports = dport + ((0ULL + lport) << 32);
         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));
         // a workaround until data6 compiles with separate lport/dport
         data6.ports = dport + ((0ULL + lport) << 32);
         data6.pid = pid;
         bpf_get_current_comm(&data6.task, sizeof(data6.task));
         ipv6_events.perf_submit(args, &data6, sizeof(data6));
     }

     u64 ts = bpf_ktime_get_ns();
     last.update(&sk, &ts);

     return 0;
 }
 """

 if (not BPF.tracepoint_exists("sock", "inet_sock_set_state")):
     print("ERROR: tracepoint sock:inet_sock_set_state missing "
         "(added in Linux 4.16). Exiting")
     exit()

 # 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)
 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()

 # event data
 TASK_COMM_LEN = 16      # linux/sched.h

 class Data_ipv4(ct.Structure):
     _fields_ = [
         ("ts_us", ct.c_ulonglong),
         ("skaddr", ct.c_ulonglong),
         ("saddr", ct.c_uint),
         ("daddr", ct.c_uint),
         ("span_us", ct.c_ulonglong),
         ("pid", ct.c_uint),
         ("ports", ct.c_uint),
         ("oldstate", ct.c_uint),
         ("newstate", ct.c_uint),
         ("task", ct.c_char * TASK_COMM_LEN)
     ]

 class Data_ipv6(ct.Structure):
     _fields_ = [
         ("ts_us", ct.c_ulonglong),
         ("skaddr", ct.c_ulonglong),
         ("saddr", (ct.c_ulonglong * 2)),
         ("daddr", (ct.c_ulonglong * 2)),
         ("span_us", ct.c_ulonglong),
         ("pid", ct.c_uint),
         ("ports", ct.c_uint),
         ("oldstate", ct.c_uint),
         ("newstate", ct.c_uint),
         ("task", ct.c_char * TASK_COMM_LEN)
     ]

 #
 # 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 %-26s %-5s %-26s %-5s %-11s " +
         "-> %-11s %s")
     format_string = ("%-16x %-5d %-16.16s %-2s %-26s %-5s %-26s %-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"

 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)

 # process event
 def print_ipv4_event(cpu, data, size):
     event = ct.cast(data, ct.POINTER(Data_ipv4)).contents
     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="")
     print(format_string % (event.skaddr, event.pid, event.task.decode('utf-8', 'replace'),
         "4" if args.wide or args.csv else "",
         inet_ntop(AF_INET, pack("I", event.saddr)), event.ports >> 32,
         inet_ntop(AF_INET, pack("I", event.daddr)), event.ports & 0xffffffff,
         tcpstate2str(event.oldstate), tcpstate2str(event.newstate),
         float(event.span_us) / 1000))

 def print_ipv6_event(cpu, data, size):
     event = ct.cast(data, ct.POINTER(Data_ipv6)).contents
     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="")
     print(format_string % (event.skaddr, event.pid, event.task.decode('utf-8', 'replace'),
         "6" if args.wide or args.csv else "",
         inet_ntop(AF_INET6, event.saddr), event.ports >> 32,
         inet_ntop(AF_INET6, event.daddr), event.ports & 0xffffffff,
         tcpstate2str(event.oldstate), tcpstate2str(event.newstate),
         float(event.span_us) / 1000))

 # 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:
     b.perf_buffer_poll()
	#!/usr/bin/python
	# @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]]
	#
	# 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 struct import pack
	import ctypes as ct
	from time import strftime

	# 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 colums (fit IPv6)
	./tcpstates -stT # csv output, with times & timestamps
	./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
	"""
	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)
	args = parser.parse_args()
	debug = 0

	# define BPF program
	bpf_text = """
	#include <uapi/linux/ptrace.h>
	#define KBUILD_MODNAME "foo"
	#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;
	u32 daddr;
	u64 span_us;
	u32 pid;
	u32 ports;
	u32 oldstate;
	u32 newstate;
	char task[TASK_COMM_LEN];
	};
	BPF_PERF_OUTPUT(ipv4_events);

	struct ipv6_data_t {
	u64 ts_us;
	u64 skaddr;
	unsigned __int128 saddr;
	unsigned __int128 daddr;
	u64 span_us;
	u32 pid;
	u32 ports;
	u32 oldstate;
	u32 newstate;
	char task[TASK_COMM_LEN];
	};
	BPF_PERF_OUTPUT(ipv6_events);

	struct id_t {
	u32 pid;
	char task[TASK_COMM_LEN];
	};

	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;

	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));
	// a workaround until data4 compiles with separate lport/dport
	data4.ports = dport + ((0ULL + lport) << 32);
	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));
	// a workaround until data6 compiles with separate lport/dport
	data6.ports = dport + ((0ULL + lport) << 32);
	data6.pid = pid;
	bpf_get_current_comm(&data6.task, sizeof(data6.task));
	ipv6_events.perf_submit(args, &data6, sizeof(data6));
	}

	u64 ts = bpf_ktime_get_ns();
	last.update(&sk, &ts);

	return 0;
	}
	"""

	if (not BPF.tracepoint_exists("sock", "inet_sock_set_state")):
	print("ERROR: tracepoint sock:inet_sock_set_state missing "
	"(added in Linux 4.16). Exiting")
	exit()

	# 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)
	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()

	# event data
	TASK_COMM_LEN = 16 # linux/sched.h

	class Data_ipv4(ct.Structure):
	_fields_ = [
	("ts_us", ct.c_ulonglong),
	("skaddr", ct.c_ulonglong),
	("saddr", ct.c_uint),
	("daddr", ct.c_uint),
	("span_us", ct.c_ulonglong),
	("pid", ct.c_uint),
	("ports", ct.c_uint),
	("oldstate", ct.c_uint),
	("newstate", ct.c_uint),
	("task", ct.c_char * TASK_COMM_LEN)
	]

	class Data_ipv6(ct.Structure):
	_fields_ = [
	("ts_us", ct.c_ulonglong),
	("skaddr", ct.c_ulonglong),
	("saddr", (ct.c_ulonglong * 2)),
	("daddr", (ct.c_ulonglong * 2)),
	("span_us", ct.c_ulonglong),
	("pid", ct.c_uint),
	("ports", ct.c_uint),
	("oldstate", ct.c_uint),
	("newstate", ct.c_uint),
	("task", ct.c_char * TASK_COMM_LEN)
	]

	#
	# 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 %-26s %-5s %-26s %-5s %-11s " +
	"-> %-11s %s")
	format_string = ("%-16x %-5d %-16.16s %-2s %-26s %-5s %-26s %-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"

	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)

	# process event
	def print_ipv4_event(cpu, data, size):
	event = ct.cast(data, ct.POINTER(Data_ipv4)).contents
	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="")
	print(format_string % (event.skaddr, event.pid, event.task.decode('utf-8', 'replace'),
	"4" if args.wide or args.csv else "",
	inet_ntop(AF_INET, pack("I", event.saddr)), event.ports >> 32,
	inet_ntop(AF_INET, pack("I", event.daddr)), event.ports & 0xffffffff,
	tcpstate2str(event.oldstate), tcpstate2str(event.newstate),
	float(event.span_us) / 1000))

	def print_ipv6_event(cpu, data, size):
	event = ct.cast(data, ct.POINTER(Data_ipv6)).contents
	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="")
	print(format_string % (event.skaddr, event.pid, event.task.decode('utf-8', 'replace'),
	"6" if args.wide or args.csv else "",
	inet_ntop(AF_INET6, event.saddr), event.ports >> 32,
	inet_ntop(AF_INET6, event.daddr), event.ports & 0xffffffff,
	tcpstate2str(event.oldstate), tcpstate2str(event.newstate),
	float(event.span_us) / 1000))

	# 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:
	b.perf_buffer_poll()