class ShellResolver(BaseResolver):
"""
Example dynamic resolver.
Maps DNS labels to shell commands and returns result as TXT record
(Note: No context is passed to the shell command)
"""
def __init__(self,routes,origin,ttl):
self.origin = DNSLabel(origin)
self.ttl = parse_time(ttl)
self.routes = {}
for r in routes:
route,_,cmd = r.partition(":")
if route.endswith('.'):
route = DNSLabel(route)
else:
route = self.origin.add(route)
self.routes[route] = cmd
def resolve(self,request,handler):
reply = request.reply()
qname = request.q.qname
cmd = self.routes.get(qname)
if cmd:
output = getoutput(cmd).encode()
reply.add_answer(RR(qname,QTYPE.TXT,ttl=self.ttl,
rdata=TXT(output[:254])))
else:
reply.header.rcode = RCODE.NXDOMAIN
return reply
class ShellResolver(BaseResolver):
"""
Example dynamic resolver.
Maps DNS labels to shell commands and returns result as TXT record
(Note: No context is passed to the shell command)
Shell commands are passed in a a list in <label>:<cmd> format - eg:
[ 'uptime.abc.com.:uptime', 'ls:ls' ]
Would respond to requests to 'uptime.abc.com.' with the output
of the 'uptime' command.
For non-absolute labels the 'origin' parameter is prepended
"""
def __init__(self, routes, origin, ttl):
self.origin = DNSLabel(origin)
self.ttl = parse_time(ttl)
self.routes = {}
for r in routes:
route, _, cmd = r.partition(":")
if route.endswith('.'):
route = DNSLabel(route)
else:
route = self.origin.add(route)
self.routes[route] = cmd
def resolve(self, request, handler):
print("resolver:" + "-" * 40)
reply = request.reply()
qname = request.q.qname
ia = ip_address(handler.client_address[0])
cmd = self.routes.get(qname)
if cmd:
output = getoutput(cmd).encode()
reply.add_answer(
RR(qname, QTYPE.TXT, ttl=self.ttl, rdata=TXT(output[:254])))
else:
rqt = QTYPE.TXT
rqd = TXT(f"{str(ia)}")
if request.q.qtype in [QTYPE.A, QTYPE.AAAA, QTYPE.PTR]:
QTR = {QTYPE.A: "A", QTYPE.AAAA: "AAAA", QTYPE.PTR: "PTR"}
qt = QTR[request.q.qtype]
if ia.version is 6 and request.q.qtype == QTYPE.AAAA:
rqt = request.q.qtype
rqd = AAAA(str(ia))
elif ia.version is 4 and request.q.qtype == QTYPE.A:
rqt = request.q.qtype
rqd = A(str(ia))
elif request.q.qtype == QTYPE.PTR:
rqt = request.q.qtype
rqd = PTR(str(ia.reverse_pointer))
else:
rqt = QTYPE.TXT
rqd = TXT(
f"Your request for {qt} confuses me, but here is the IP as text {str(ia)}"
)
reply.add_answer(RR(qname, rqt, ttl=self.ttl, rdata=rqd))
return reply
class ShellResolver(BaseResolver):
"""
Example dynamic resolver.
Maps DNS labels to shell commands and returns result as TXT record
(Note: No context is passed to the shell command)
"""
def __init__(self, routes, origin, ttl):
self.origin = DNSLabel(origin)
self.ttl = parse_time(ttl)
self.routes = {}
for r in routes:
route, _, cmd = r.partition(":")
if route.endswith('.'):
route = DNSLabel(route)
else:
route = self.origin.add(route)
self.routes[route] = cmd
def resolve(self, request, handler):
reply = request.reply()
qname = request.q.qname
cmd = self.routes.get(qname)
if cmd:
output = getoutput(cmd).encode()
reply.add_answer(
RR(qname, QTYPE.TXT, ttl=self.ttl, rdata=TXT(output[:254])))
else:
reply.header.rcode = RCODE.NXDOMAIN
return reply
def _generate_as_topo(self, topo_id, as_conf):
dns_domain = DNSLabel(as_conf.get("dns_domain", DEFAULT_DNS_DOMAIN))
dns_domain = dns_domain.add("isd%s" % topo_id[0]).add("as%s" %
topo_id[1])
mtu = as_conf.get('mtu', self.default_mtu)
assert mtu >= SCION_MIN_MTU, mtu
self.topo_dicts[topo_id] = {
'Core': as_conf.get('core', False),
'ISD_AS': str(topo_id),
'DnsDomain': str(dns_domain),
'Zookeepers': {},
'MTU': mtu,
}
for i in SCION_SERVICE_NAMES:
self.topo_dicts[topo_id][i] = {}
self._gen_srv_entries(topo_id, as_conf, dns_domain)
self._gen_er_entries(topo_id)
self._gen_zk_entries(topo_id, as_conf)
class ShellResolver(BaseResolver):
"""
Example dynamic resolver.
Maps DNS labels to shell commands and returns result as TXT record
(Note: No context is passed to the shell command)
Shell commands are passed in a a list in <label>:<cmd> format - eg:
[ 'uptime.abc.com.:uptime', 'ls:ls' ]
Would respond to requests to 'uptime.abc.com.' with the output
of the 'uptime' command.
For non-absolute labels the 'origin' parameter is prepended
"""
def __init__(self,routes,origin,ttl):
self.origin = DNSLabel(origin)
self.ttl = parse_time(ttl)
self.routes = {}
for r in routes:
route,_,cmd = r.partition(":")
if route.endswith('.'):
route = DNSLabel(route)
else:
route = self.origin.add(route)
self.routes[route] = cmd
def resolve(self,request,handler):
reply = request.reply()
qname = request.q.qname
cmd = self.routes.get(qname)
if cmd:
output = getoutput(cmd).encode()
reply.add_answer(RR(qname,QTYPE.TXT,ttl=self.ttl,
rdata=TXT(output[:254])))
else:
reply.header.rcode = RCODE.NXDOMAIN
return reply
class ShellResolver(BaseResolver):
"""
Example dynamic resolver.
Maps DNS labels to shell commands and returns result as TXT record
(Note: No context is passed to the shell command)
Shell commands are passed in a a list in <label>:<cmd> format - eg:
[ 'uptime.abc.com.:uptime', 'ls:ls' ]
Would respond to requests to 'uptime.abc.com.' with the output
of the 'uptime' command.
For non-absolute labels the 'origin' parameter is prepended
"""
def __init__(self, routes, origin, ttl):
self.origin = DNSLabel(origin)
self.ttl = parse_time(ttl)
self.routes = {}
for r in routes:
route, _, cmd = r.partition(":")
if route.endswith('.'):
route = DNSLabel(route)
else:
route = self.origin.add(route)
self.routes[route] = cmd
def resolve(self, request, handler):
reply = request.reply()
qname = request.q.qname
cmd = self.routes.get(qname)
if cmd:
output = getoutput(cmd).encode()
reply.add_answer(
RR(qname, QTYPE.TXT, ttl=self.ttl, rdata=TXT(output[:254])))
else:
reply.header.rcode = RCODE.NXDOMAIN
return reply
class ZoneParser:
"""
Zone file parser
>>> z = ZoneParser("www.example.com. 60 IN A 1.2.3.4")
>>> list(z.parse())
[<DNS RR: 'www.example.com.' rtype=A rclass=IN ttl=60 rdata='1.2.3.4'>]
"""
def __init__(self, zone, origin="", ttl=0):
self.l = WordLexer(zone)
self.l.commentchars = ";"
self.l.nltok = ("NL", None)
self.l.spacetok = ("SPACE", None)
self.i = iter(self.l)
if type(origin) is DNSLabel:
self.origin = origin
else:
self.origin = DNSLabel(origin)
self.ttl = ttl
self.label = DNSLabel("")
self.prev = None
def expect(self, expect):
t, val = next(self.i)
if t != expect:
raise ValueError("Invalid Token: %s (expecting: %s)" % (t, expect))
return val
def parse_label(self, label):
if label.endswith("."):
self.label = DNSLabel(label)
elif label == "@":
self.label = self.origin
elif label == "":
pass
else:
self.label = self.origin.add(label)
return self.label
def parse_rr(self, rr):
label = self.parse_label(rr.pop(0))
ttl = int(rr.pop(0)) if rr[0].isdigit() else self.ttl
rclass = rr.pop(0) if rr[0] in ("IN", "CH", "HS") else "IN"
rtype = rr.pop(0)
rdata = rr
rd = RDMAP.get(rtype, RD)
return RR(
rname=label,
ttl=ttl,
rclass=getattr(CLASS, rclass),
rtype=getattr(QTYPE, rtype),
rdata=rd.fromZone(rdata, self.origin),
)
def __iter__(self):
return self.parse()
def parse(self):
rr = []
paren = False
try:
while True:
tok, val = next(self.i)
if tok == "NL":
if not paren and rr:
self.prev = tok
yield self.parse_rr(rr)
rr = []
elif tok == "SPACE" and self.prev == "NL" and not paren:
rr.append("")
elif tok == "ATOM":
if val == "(":
paren = True
elif val == ")":
paren = False
elif val == "$ORIGIN":
self.expect("SPACE")
origin = self.expect("ATOM")
self.origin = self.label = DNSLabel(origin)
elif val == "$TTL":
self.expect("SPACE")
ttl = self.expect("ATOM")
self.ttl = parse_time(ttl)
else:
rr.append(val)
self.prev = tok
except StopIteration:
if rr:
yield self.parse_rr(rr)
class ZoneParser:
"""
Zone file parser
>>> z = ZoneParser("www.example.com. 60 IN A 1.2.3.4")
>>> list(z.parse())
[<DNS RR: 'www.example.com.' rtype=A rclass=IN ttl=60 rdata='1.2.3.4'>]
"""
def __init__(self,zone,origin="",ttl=0):
self.l = WordLexer(zone)
self.l.commentchars = ';'
self.l.nltok = ('NL',None)
self.l.spacetok = ('SPACE',None)
self.i = iter(self.l)
if type(origin) is DNSLabel:
self.origin = origin
else:
self.origin= DNSLabel(origin)
self.ttl = ttl
self.label = DNSLabel("")
self.prev = None
def expect(self,expect):
t,val = next(self.i)
if t != expect:
raise ValueError("Invalid Token: %s (expecting: %s)" % (t,expect))
return val
def parse_label(self,label):
if label.endswith("."):
self.label = DNSLabel(label)
elif label == "@":
self.label = self.origin
elif label == '':
pass
else:
self.label = self.origin.add(label)
return self.label
def parse_rr(self,rr):
label = self.parse_label(rr.pop(0))
ttl = int(rr.pop(0)) if rr[0].isdigit() else self.ttl
rclass = rr.pop(0) if rr[0] in ('IN','CH','HS') else 'IN'
rtype = rr.pop(0)
rdata = rr
rd = RDMAP.get(rtype,RD)
return RR(rname=label,
ttl=ttl,
rclass=getattr(CLASS,rclass),
rtype=getattr(QTYPE,rtype),
rdata=rd.fromZone(rdata,self.origin))
def __iter__(self):
return self.parse()
def parse(self):
rr = []
paren = False
try:
while True:
tok,val = next(self.i)
if tok == 'NL':
if not paren and rr:
self.prev = tok
yield self.parse_rr(rr)
rr = []
elif tok == 'SPACE' and self.prev == 'NL' and not paren:
rr.append('')
elif tok == 'ATOM':
if val == '(':
paren = True
elif val == ')':
paren = False
elif val == '$ORIGIN':
self.expect('SPACE')
origin = self.expect('ATOM')
self.origin = self.label = DNSLabel(origin)
elif val == '$TTL':
self.expect('SPACE')
ttl = self.expect('ATOM')
self.ttl = parse_time(ttl)
else:
rr.append(val)
self.prev = tok
except StopIteration:
if rr:
yield self.parse_rr(rr)
