mirror of
https://github.com/sshuttle/sshuttle.git
synced 2024-11-21 15:33:23 +01:00
Enhanced DNS support. Initial version.
This commit is contained in:
Brian May
parent
783d33cada
commit
9915d736fe
104
client.py
104
client.py
@ -175,8 +175,60 @@ class FirewallClient:
|
||||
raise Fatal('cleanup: %r returned %d' % (self.argv, rv))
|
||||
|
||||
|
||||
def unpack_dns_name(buf, off):
|
||||
name = ''
|
||||
while True:
|
||||
# get the next octet from buffer
|
||||
n = ord(buf[off])
|
||||
|
||||
# zero octet terminates name
|
||||
if n == 0:
|
||||
off += 1
|
||||
break
|
||||
|
||||
# top two bits on
|
||||
# => a 2 octect pointer to another part of the buffer
|
||||
elif (n & 0xc0) == 0xc0:
|
||||
ptr = struct.unpack('>H', buf[off:off+2])[0] & 0x3fff
|
||||
off = ptr
|
||||
|
||||
# an octet representing the number of bytes to process.
|
||||
else:
|
||||
off += 1
|
||||
name = name + buf[off:off+n] + '.'
|
||||
off += n
|
||||
|
||||
return name.strip('.'), off
|
||||
|
||||
class dnspkt:
|
||||
def unpack(self, buf, off):
|
||||
l = len(buf)
|
||||
|
||||
(self.id, self.op, self.qdcount, self.ancount, self.nscount, self.arcount) = struct.unpack("!HHHHHH",buf[off:off+12])
|
||||
off += 12
|
||||
|
||||
self.q = []
|
||||
for i in range(self.qdcount):
|
||||
qname, off = unpack_dns_name(buf, off)
|
||||
qtype, qclass = struct.unpack('!HH', buf[off:off+4])
|
||||
off += 4
|
||||
self.q.append( (qname,qtype,qclass) )
|
||||
|
||||
return off
|
||||
|
||||
def match_q_domain(self, domain):
|
||||
l = len(domain)
|
||||
for qname,qtype,qclass in self.q:
|
||||
if qname[-l:] == domain:
|
||||
if l==len(qname):
|
||||
return True
|
||||
elif qname[-l-1] == '.':
|
||||
return True
|
||||
return False
|
||||
|
||||
def _main(listener, fw, ssh_cmd, remotename, python, latency_control,
|
||||
dnslistener, seed_hosts, auto_nets,
|
||||
dnslistener, dnsforwarder, dns_domains, dns_to,
|
||||
seed_hosts, auto_nets,
|
||||
syslog, daemon):
|
||||
handlers = []
|
||||
if helpers.verbose >= 1:
|
||||
@ -283,6 +335,7 @@ def _main(listener, fw, ssh_cmd, remotename, python, latency_control,
|
||||
handlers.append(Handler([listener], onaccept))
|
||||
|
||||
dnsreqs = {}
|
||||
dnsforwards = {}
|
||||
def dns_done(chan, data):
|
||||
peer,timeout = dnsreqs.get(chan) or (None,None)
|
||||
debug3('dns_done: channel=%r peer=%r\n' % (chan, peer))
|
||||
@ -295,16 +348,54 @@ def _main(listener, fw, ssh_cmd, remotename, python, latency_control,
|
||||
now = time.time()
|
||||
if pkt:
|
||||
debug1('DNS request from %r: %d bytes\n' % (peer, len(pkt)))
|
||||
dns = dnspkt()
|
||||
dns.unpack(pkt, 0)
|
||||
|
||||
match=False
|
||||
if dns_domains is not None:
|
||||
for domain in dns_domains:
|
||||
if dns.match_q_domain(domain):
|
||||
match=True
|
||||
break
|
||||
|
||||
if match:
|
||||
debug3("We need to redirect this request remotely\n")
|
||||
chan = mux.next_channel()
|
||||
dnsreqs[chan] = peer,now+30
|
||||
mux.send(chan, ssnet.CMD_DNS_REQ, pkt)
|
||||
mux.channels[chan] = lambda cmd,data: dns_done(chan,data)
|
||||
else:
|
||||
debug3("We need to forward this request locally\n")
|
||||
dnsforwarder.sendto(pkt, dns_to)
|
||||
dnsforwards[dns.id] = peer,now+30
|
||||
for chan,(peer,timeout) in dnsreqs.items():
|
||||
if timeout < now:
|
||||
del dnsreqs[chan]
|
||||
for chan,(peer,timeout) in dnsforwards.items():
|
||||
if timeout < now:
|
||||
del dnsforwards[chan]
|
||||
debug3('Remaining DNS requests: %d\n' % len(dnsreqs))
|
||||
debug3('Remaining DNS forwards: %d\n' % len(dnsforwards))
|
||||
if dnslistener:
|
||||
handlers.append(Handler([dnslistener], ondns))
|
||||
def ondnsforward():
|
||||
debug1("We got a response.\n")
|
||||
pkt,server = dnsforwarder.recvfrom(4096)
|
||||
now = time.time()
|
||||
if server[0] != dns_to[0] or server[1] != dns_to[1]:
|
||||
debug1("Ooops. The response came from the wrong server. Ignoring\n")
|
||||
else:
|
||||
dns = dnspkt()
|
||||
dns.unpack(pkt, 0)
|
||||
chan=dns.id
|
||||
peer,timeout = dnsforwards.get(chan) or (None,None)
|
||||
debug3('dns_done: channel=%r peer=%r\n' % (chan, peer))
|
||||
if peer:
|
||||
del dnsforwards[chan]
|
||||
debug3('doing sendto %r\n' % (peer,))
|
||||
dnslistener.sendto(pkt, peer)
|
||||
if dnsforwarder:
|
||||
handlers.append(Handler([dnsforwarder], ondnsforward))
|
||||
|
||||
if seed_hosts != None:
|
||||
debug1('seed_hosts: %r\n' % seed_hosts)
|
||||
@ -321,7 +412,8 @@ def _main(listener, fw, ssh_cmd, remotename, python, latency_control,
|
||||
mux.callback()
|
||||
|
||||
|
||||
def main(listenip, ssh_cmd, remotename, python, latency_control, dns,
|
||||
def main(listenip, ssh_cmd, remotename, python, latency_control,
|
||||
dns, dns_domains, dns_to,
|
||||
seed_hosts, auto_nets,
|
||||
subnets_include, subnets_exclude, syslog, daemon, pidfile):
|
||||
if syslog:
|
||||
@ -366,15 +458,21 @@ def main(listenip, ssh_cmd, remotename, python, latency_control, dns,
|
||||
dnsip = dnslistener.getsockname()
|
||||
debug1('DNS listening on %r.\n' % (dnsip,))
|
||||
dnsport = dnsip[1]
|
||||
|
||||
dnsforwarder = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
|
||||
dnsforwarder.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
|
||||
dnsforwarder.setsockopt(socket.SOL_IP, socket.IP_TTL, 42)
|
||||
else:
|
||||
dnsport = 0
|
||||
dnslistener = None
|
||||
dnsforwarder = None
|
||||
|
||||
fw = FirewallClient(listenip[1], subnets_include, subnets_exclude, dnsport)
|
||||
|
||||
try:
|
||||
return _main(listener, fw, ssh_cmd, remotename,
|
||||
python, latency_control, dnslistener,
|
||||
python, latency_control,
|
||||
dnslistener, dnsforwarder, dns_domains, dns_to,
|
||||
seed_hosts, auto_nets, syslog, daemon)
|
||||
finally:
|
||||
try:
|
||||
|
||||
18
main.py
18
main.py
@ -54,6 +54,8 @@ l,listen= transproxy to this ip address and port number [127.0.0.1:0]
|
||||
H,auto-hosts scan for remote hostnames and update local /etc/hosts
|
||||
N,auto-nets automatically determine subnets to route
|
||||
dns capture local DNS requests and forward to the remote DNS server
|
||||
dns-domains= comma seperated list of DNS domains for DNS forwarding
|
||||
dns-to= forward any DNS requests that don't match domains to this address
|
||||
python= path to python interpreter on the remote server
|
||||
r,remote= ssh hostname (and optional username) of remote sshuttle server
|
||||
x,exclude= exclude this subnet (can be used more than once)
|
||||
@ -110,12 +112,26 @@ try:
|
||||
sh = []
|
||||
else:
|
||||
sh = None
|
||||
if opt.dns and opt.dns_domains:
|
||||
dns_domains = opt.dns_domains.split(",")
|
||||
if opt.dns_to:
|
||||
addr,colon,port = opt.dns_to.rpartition(":")
|
||||
if colon == ":":
|
||||
dns_to = ( addr, int(port) )
|
||||
else:
|
||||
dns_to = ( port, 53 )
|
||||
else:
|
||||
o.fatal('--dns-to=ip is required with --dns-domains=list')
|
||||
else:
|
||||
dns_domains = None
|
||||
dns_to = None
|
||||
|
||||
sys.exit(client.main(parse_ipport(opt.listen or '0.0.0.0:0'),
|
||||
opt.ssh_cmd,
|
||||
remotename,
|
||||
opt.python,
|
||||
opt.latency_control,
|
||||
opt.dns,
|
||||
opt.dns, dns_domains, dns_to,
|
||||
sh,
|
||||
opt.auto_nets,
|
||||
parse_subnets(includes),
|
||||
|
||||
Loading…
Reference in New Issue
Block a user