from optparse import OptionParser
import cdb as CDB
from sys import stdin, stdout, exit, argv
+import subprocess as SUB
import re as RX
import os as OS
+import errno as E
+import fcntl as F
+import socket as S
from cStringIO import StringIO
###--------------------------------------------------------------------------
def __init__(me, name):
"""Make a new resolving-host object for the host NAME."""
me.name = name
- me.addr = { 'INET': [] }
+ me.addr = { 'INET': [], 'INET6': [] }
me.failure = None
def addaddr(me, af, addr):
"""
Add the address ADDR with address family AF.
- The address family must currently be `INET'.
+ The address family may be `INET' or `INET6'.
"""
me.addr[af].append(addr)
if me.failure is not None: raise ResolverFailure(me.name, me.failure)
aa = []
a4 = me.addr['INET']
+ a6 = me.addr['INET6']
all, any = False, False
for ch in flags:
if ch == '*': all = True
elif ch == '4': aa += a4; any = True
+ elif ch == '6': aa += a6; any = True
else: raise ValueError("unknown address-resolution flag `%s'" % ch)
- if not any: aa = a4
+ if not any: aa = a4 + a6
if not aa: raise ResolverFailure(me.name, 'no matching addresses found')
if not all: aa = [aa[0]]
return aa
-class BulkResolver (object):
+class BaseBulkResolver (object):
"""
Resolve a number of DNS names in parallel.
def __init__(me):
"""Initialize the resolver."""
me._namemap = {}
+
+ def prepare(me, name):
+ """Prime the resolver to resolve the given host NAME."""
+ if name not in me._namemap:
+ me._namemap[name] = host = ResolvingHost(name)
+ try:
+ ailist = S.getaddrinfo(name, None, S.AF_UNSPEC, S.SOCK_DGRAM, 0,
+ S.AI_NUMERICHOST | S.AI_NUMERICSERV)
+ except S.gaierror:
+ me._prepare(host, name)
+ else:
+ for af, skty, proto, cname, sa in ailist:
+ if af == S.AF_INET: host.addaddr('INET', sa[0])
+ elif af == S.AF_INET6: host.addaddr('INET6', sa[0])
+
+ def lookup(me, name, flags):
+ """Fetch the address corresponding to the host NAME."""
+ return me._namemap[name].get(flags)
+
+class BresBulkResolver (BaseBulkResolver):
+ """
+ A BulkResolver using mLib's `bres' background resolver.
+
+ This is always available (and might use ADNS), but only does IPv4.
+ """
+
+ def __init__(me):
+ super(BresBulkResolver, me).__init__()
+ """Initialize the resolver."""
me._noutstand = 0
def _prepare(me, host, name):
lambda: me._resolved(host, None, []))
me._noutstand += 1
- def prepare(me, name):
- """Prime the resolver to resolve the given host NAME."""
- if name not in me._namemap:
- me._namemap[name] = host = ResolvingHost(name)
- me._prepare(host, name)
-
def run(me):
"""Run the background DNS resolver until it's finished."""
while me._noutstand: M.select()
- def lookup(me, name, flags):
- """Fetch the address corresponding to the host NAME."""
- return me._namemap[name].get(flags)
-
def _resolved(me, host, cname, addr):
"""Callback function: remember that ADDRs are the addresses for HOST."""
if not addr:
host._resolv = None
me._noutstand -= 1
+class AdnsBulkResolver (BaseBulkResolver):
+ """
+ A BulkResolver using ADNS, via the `adnshost' command-line tool.
+
+ This can do simultaneous IPv4 and IPv6 lookups and is quite shiny.
+ """
+
+ def __init__(me):
+ """Initialize the resolver."""
+
+ super(AdnsBulkResolver, me).__init__()
+
+ ## Start the external resolver process.
+ me._kid = SUB.Popen(['adnshost', '-afs'],
+ stdin = SUB.PIPE, stdout = SUB.PIPE)
+
+ ## Set up the machinery for feeding input to the resolver.
+ me._in = me._kid.stdin
+ M.fdflags(me._in, fbic = OS.O_NONBLOCK, fxor = OS.O_NONBLOCK)
+ me._insel = M.SelFile(me._in.fileno(), M.SEL_WRITE, me._write)
+ me._inbuf, me._inoff, me._inlen = '', 0, 0
+ me._idmap = {}
+ me._nextid = 0
+
+ ## Set up the machinery for collecting the resolver's output.
+ me._out = me._kid.stdout
+ M.fdflags(me._out, fbic = OS.O_NONBLOCK, fxor = OS.O_NONBLOCK)
+ me._outline = M.SelLineBuffer(me._out,
+ lineproc = me._hostline, eofproc = me._eof)
+ me._outline.enable()
+
+ ## It's not finished yet.
+ me._done = False
+
+ def _prepare(me, host, name):
+ """Arrange for the resolver to resolve the name NAME."""
+
+ ## Work out the next job id, and associate that with the host record.
+ host.id = me._nextid; me._nextid += 1
+ me._namemap[name] = me._idmap[host.id] = host
+
+ ## Feed the name to the resolver process.
+ me._inbuf += name + '\n'
+ me._inlen += len(name) + 1
+ if not me._insel.activep: me._insel.enable()
+ while me._inoff < me._inlen: M.select()
+
+ def _write(me):
+ """Write material from `_inbuf' to the resolver when it's ready."""
+
+ ## Try to feed some more material to the resolver.
+ try: n = OS.write(me._in.fileno(), me._inbuf[me._inoff:])
+ except OSError, e:
+ if e.errno == E.EAGAIN or e.errno == E.EWOULDBLOCK: return
+ else: raise
+
+ ## If we're done, then clear the buffer.
+ me._inoff += n
+ if me._inoff >= me._inlen:
+ me._insel.disable()
+ me._inbuf, me._inoff, me._inlen = '', 0, 0
+
+ def _eof(me):
+ """Notice that the resolver has finished."""
+ me._outline.disable()
+ me._done = True
+ me._kid.wait()
+
+ def run(me):
+ """
+ Tell the resolver it has all of our input now, and wait for it to finish.
+ """
+ me._in.close()
+ while not me._done: M.select()
+ if me._idmap:
+ raise Exception('adnshost failed to process all the requests')
+
+ def _hostline(me, line):
+ """Handle a host line from the resolver."""
+
+ ## Parse the line into fields.
+ (id, nrrs, stty, stocde, stmsg, owner, cname, ststr), _ = \
+ M.split(line, quotep = True)
+ id, nrrs = int(id), int(nrrs)
+
+ ## Find the right record.
+ host = me._idmap[id]
+ if stty != 'ok': host.failed(ststr)
+
+ ## Stash away the canonical name of the host.
+ host.name = cname == '$' and owner or cname
+
+ ## If there are no record lines to come, then remove this record from the
+ ## list of outstanding jobs. Otherwise, switch to the handler for record
+ ## lines.
+ if not nrrs:
+ del me._idmap[id]
+ else:
+ me._outline.lineproc = me._rrline
+ me._nrrs = nrrs
+ me._outhost = host
+
+ def _rrline(me, line):
+ """Handle a record line from the resolver."""
+
+ ## Parse the line into fields.
+ ww, _ = M.split(line, quotep = True)
+ owner, type, af = ww[:3]
+
+ ## If this is an address record, and it looks like an interesting address
+ ## type, then stash the address.
+ if type == 'A' and (af == 'INET' or af == 'INET6'):
+ me._outhost.addaddr(af, ww[3])
+
+ ## Update the parser state. If there are no more records for this job
+ ## then mark the job as done and switch back to expecting a host line.
+ me._nrrs -= 1
+ if not me._nrrs:
+ me._outline.lineproc = me._hostline
+ del me._idmap[me._outhost.id]
+ me._outhost = None
+
+## Select a bulk resolver. If `adnshost' exists then we might as well use
+## it.
+BulkResolver = BresBulkResolver
+try:
+ p = SUB.Popen(['adnshost', '--version'],
+ stdin = SUB.PIPE, stdout = SUB.PIPE, stderr = SUB.PIPE)
+ _out, _err = p.communicate()
+ st = p.wait()
+ if st == 0: BulkResolver = AdnsBulkResolver
+except OSError:
+ pass
+
###--------------------------------------------------------------------------
### The configuration parser.
## Match a $FLAGS[HOST] name resolution reference; group 1 are the flags;
## group 2 is the HOST.
-RX_RESOLVE = RX.compile(r'(?x) \$ ([4*]*) \[ ([^]]+) \]')
+RX_RESOLVE = RX.compile(r'(?x) \$ ([46*]*) \[ ([^]]+) \]')
class ConfigSyntaxError (ExpectedError):
def __init__(me, fname, lno, msg):
path.append(me.name)
try:
- ## If we've been this way before on another pass through then return the
- ## value we found then. If we're still thinking about it then we've
- ## found a cycle.
+ ## If we've been this way before on another pass through then return
+ ## the value we found then. If we're still thinking about it then
+ ## we've found a cycle.
try: v, p = me._cache[key]
except KeyError: pass
else:
expansion and processes them correctly.
* It recognizes `$FLAGS[HOST]' name-resolver requests and handles them
- correctly. FLAGS consists of characters `4' (IPv4 addresses), and `*'
- (all addresses, space-separated, rather than just the first).
+ correctly. FLAGS consists of characters `4' (IPv4 addresses), `6'
+ (IPv6 addresses), and `*' (all, space-separated, rather than just the
+ first).
* Its parsing behaviour is well-defined.
if a in ('y', 'yes', 't', 'true', '1', 'on'): auto.append(sec.name)
try: u = sec.get('user')
except MissingKeyException: pass
- else: cdb.add('U%s' % u)
+ else: cdb.add('U%s' % u, sec.name)
url = M.URLEncode(semip = True)
for key in sorted(sec.items()):
if not key.startswith('@'):