def handle_time_exceeded(ip_packet):
time_exceed = ip_packet.icmp.data
if not isinstance(time_exceed.data, dpkt.ip.IP):
return
te_ip_packet = time_exceed.data
if not isinstance(te_ip_packet.data, dpkt.icmp.ICMP):
return
te_icmp_packet = te_ip_packet.data
if not isinstance(te_icmp_packet.data, dpkt.icmp.ICMP.Echo):
return
te_icmp_echo = te_icmp_packet.data
ttl = te_icmp_echo.id
dst_ip = socket.inet_ntoa(te_ip_packet.dst)
router_ip = socket.inet_ntoa(ip_packet.src)
is_china_router = china_ip.is_china_ip(router_ip)
if is_china_router and MAX_TTL_TO_GFW == ttl:
LOGGER.info(
'treat ip as domestic as max ttl is still in china: %s, %s' %
(dst_ip, pending_connection.get_detected_routers(dst_ip)))
add_domestic_ip(dst_ip)
return
else:
pending_connection.record_router(dst_ip, ttl, is_china_router)
ttl_to_gfw = pending_connection.get_ttl_to_gfw(dst_ip)
if ttl_to_gfw:
LOGGER.info('found ttl to gfw: %s %s' %
(dst_ip, ttl_to_gfw - SAFETY_DELTA))
add_international_ip(dst_ip, ttl_to_gfw - SAFETY_DELTA)
def handle_time_exceeded(ip_packet):
time_exceed = ip_packet.icmp.data
if not isinstance(time_exceed.data, dpkt.ip.IP):
return
te_ip_packet = time_exceed.data
if not isinstance(te_ip_packet.data, dpkt.icmp.ICMP):
return
te_icmp_packet = te_ip_packet.data
if not isinstance(te_icmp_packet.data, dpkt.icmp.ICMP.Echo):
return
te_icmp_echo = te_icmp_packet.data
ttl = te_icmp_echo.id
dst_ip = socket.inet_ntoa(te_ip_packet.dst)
router_ip = socket.inet_ntoa(ip_packet.src)
is_china_router = china_ip.is_china_ip(router_ip)
if is_china_router and MAX_TTL_TO_GFW == ttl:
LOGGER.info('treat ip as domestic as max ttl is still in china: %s, %s' %
(dst_ip, pending_connection.get_detected_routers(dst_ip)))
add_domestic_ip(dst_ip)
return
else:
pending_connection.record_router(dst_ip, ttl, is_china_router)
ttl_to_gfw = pending_connection.get_ttl_to_gfw(dst_ip)
if ttl_to_gfw:
LOGGER.info('found ttl to gfw: %s %s' % (dst_ip, ttl_to_gfw - SAFETY_DELTA))
add_international_ip(dst_ip, ttl_to_gfw - SAFETY_DELTA)
def handle_syn_ack(syn_ack):
uncertain_ip = socket.inet_ntoa(syn_ack.src)
full_proxy_service.add_to_white_list(uncertain_ip)
if uncertain_ip in pending_syn:
del pending_syn[uncertain_ip]
expected_ttl = syn_ack_ttl.get((uncertain_ip, syn_ack.tcp.sport)) or 0
if expected_ttl and abs(syn_ack.ttl - expected_ttl) > 2:
log_jamming_event(uncertain_ip, 'tcp syn ack spoofing')
LOGGER.error(
'received spoofed SYN ACK: expected ttl is %s, actually is %s, the packet %s'
% (expected_ttl, syn_ack.ttl, format_ip_packet(syn_ack)))
syn_ack_ttl[(
uncertain_ip, syn_ack.tcp.sport
)] = syn_ack.ttl # later one should be the correct one as GFW is closer to us
if uncertain_ip in international_zone:
inject_poison_ack_to_fill_gfw_buffer_with_garbage(
syn_ack, international_zone[uncertain_ip])
return True
elif uncertain_ip in domestic_zone:
return True
elif pending_connection.is_ip_pending(uncertain_ip):
pending_connection.record_syn_ack(syn_ack)
timeouted = pending_connection.is_ip_timeouted(uncertain_ip)
if timeouted:
international_ip = uncertain_ip
LOGGER.info(
'treat ip as international due to timeout: %s, %s' %
(international_ip,
pending_connection.get_detected_routers(international_ip)))
ttl_to_gfw = pending_connection.get_ttl_to_gfw(
international_ip, exact_match_only=False)
add_international_ip(international_ip,
(ttl_to_gfw or DEFAULT_TTL_TO_GFW) -
SAFETY_DELTA)
return False
elif china_ip.is_china_ip(uncertain_ip):
domestic_ip = uncertain_ip
LOGGER.info('found domestic ip: %s' % domestic_ip)
domestic_zone.add(domestic_ip)
return True
else:
pending_connection.record_syn_ack(syn_ack)
inject_ping_requests_to_find_right_ttl(uncertain_ip)
return False
def handle_syn_ack(syn_ack):
uncertain_ip = socket.inet_ntoa(syn_ack.src)
full_proxy_service.add_to_white_list(uncertain_ip)
if uncertain_ip in pending_syn:
del pending_syn[uncertain_ip]
expected_ttl = syn_ack_ttl.get((uncertain_ip, syn_ack.tcp.sport)) or 0
if expected_ttl and abs(syn_ack.ttl - expected_ttl) > 2:
log_jamming_event(uncertain_ip, 'tcp syn ack spoofing')
LOGGER.error(
'received spoofed SYN ACK: expected ttl is %s, actually is %s, the packet %s' %
(expected_ttl, syn_ack.ttl, format_ip_packet(syn_ack)))
syn_ack_ttl[
(uncertain_ip, syn_ack.tcp.sport)] = syn_ack.ttl # later one should be the correct one as GFW is closer to us
if uncertain_ip in international_zone:
inject_poison_ack_to_fill_gfw_buffer_with_garbage(syn_ack, international_zone[uncertain_ip])
return True
elif uncertain_ip in domestic_zone:
return True
elif pending_connection.is_ip_pending(uncertain_ip):
pending_connection.record_syn_ack(syn_ack)
timeouted = pending_connection.is_ip_timeouted(uncertain_ip)
if timeouted:
international_ip = uncertain_ip
ttl_to_gfw = pending_connection.get_ttl_to_gfw(international_ip, exact_match_only=False)
LOGGER.info('treat ip as international due to timeout: %s, %s, %s' %
(international_ip, ttl_to_gfw, pending_connection.get_detected_routers(international_ip)))
add_international_ip(international_ip, (ttl_to_gfw or DEFAULT_TTL_TO_GFW) - SAFETY_DELTA)
return False
elif china_ip.is_china_ip(uncertain_ip):
domestic_ip = uncertain_ip
LOGGER.info('found domestic ip: %s' % domestic_ip)
domestic_zone.add(domestic_ip)
return True
else:
pending_connection.record_syn_ack(syn_ack)
inject_ping_requests_to_find_right_ttl(uncertain_ip)
return False
