vbatts/shadowsocks
1
0
Fork 0
Code Issues Pull requests Releases Wiki Activity

use multiple DNS instead of trying each one

Browse source
This commit is contained in:
clowwindy 2014-06-23 21:46:23 +08:00
parent d4458bceb7
commit 012ab70500
1 changed files with 11 additions and 25 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

36
shadowsocks/asyncdns.py
View file

@ -32,7 +32,7 @@ import lru_cache
import eventloop
CACHE_SWEEP_INTERVAL = 10
CACHE_SWEEP_INTERVAL = 30
VALID_HOSTNAME = re.compile("(?!-)[A-Z\d-]{1,63}(?<!-)$", re.IGNORECASE)
@ -267,21 +267,18 @@ class DNSResolver(object):
self._hosts = {}
self._hostname_status = {}
self._hostname_to_cb = {}
self._cb_to_hostname = lru_cache.LRUCache(timeout=15,
close_callback=self._timedout)
self._cb_to_hostname = {}
self._cache = lru_cache.LRUCache(timeout=300)
self._last_time = time.time()
self._sock = None
self._servers = None
self._server_index = 0
self._parse_resolv()
self._parse_hosts()
# TODO monitor hosts change and reload hosts
# TODO parse /etc/gai.conf and follow its rules
def _parse_resolv(self):
servers = []
self._servers = servers
self._servers = []
try:
with open('/etc/resolv.conf', 'rb') as f:
content = f.readlines()
@ -293,22 +290,11 @@ class DNSResolver(object):
if len(parts) >= 2:
server = parts[1]
if is_ip(server):
servers.append(server)
# TODO support more servers
self._servers.append(server)
except IOError:
pass
if not servers:
servers.append('8.8.8.8')
self._dns_server = (servers[0], 53)
def _timedout(self, hostname):
error = Exception('timed out when resolving %s with DNS %s' %
(hostname, self._dns_server))
self._server_index += 1
self._server_index %= len(self._servers)
self._dns_server = (self._servers[self._server_index], 53)
self._call_callback(hostname, None, error=error)
if not self._servers:
self._servers = ['8.8.4.4', '8.8.8.8']
def _parse_hosts(self):
etc_path = '/etc/hosts'
@ -389,7 +375,7 @@ class DNSResolver(object):
self._loop.add(self._sock, eventloop.POLL_IN)
else:
data, addr = sock.recvfrom(1024)
if addr != self._dns_server:
if addr[0] not in self._servers:
logging.warn('received a packet other than our dns')
break
self._handle_data(data)
@ -397,7 +383,6 @@ class DNSResolver(object):
now = time.time()
if now - self._last_time > CACHE_SWEEP_INTERVAL:
self._cache.sweep()
self._cb_to_hostname.sweep()
self._last_time = now
def remove_callback(self, callback):
@ -413,13 +398,14 @@ class DNSResolver(object):
del self._hostname_status[hostname]
def _send_req(self, hostname, qtype):
logging.debug('resolving %s with type %d using server %s', hostname,
qtype, self._dns_server)
self._request_id += 1
if self._request_id > 32768:
self._request_id = 1
req = build_request(hostname, qtype, self._request_id)
self._sock.sendto(req, self._dns_server)
for server in self._servers:
logging.debug('resolving %s with type %d using server %s', hostname,
qtype, server)
self._sock.sendto(req, (server, 53))
def resolve(self, hostname, callback):
if not hostname: