peerdb/tripe-newpeers.in: Split out a resolver base class.

[tripe] / peerdb / tripe-newpeers.in

diff --git a/peerdb/tripe-newpeers.in b/peerdb/tripe-newpeers.in
index 4476197..202cea8 100644 (file)
--- a/peerdb/tripe-newpeers.in
+++ b/peerdb/tripe-newpeers.in
@@ -34,6 +34,7 @@ import cdb as CDB
 from sys import stdin, stdout, exit, argv
 import re as RX
 import os as OS
+import socket as S
 from cStringIO import StringIO
 
 ###--------------------------------------------------------------------------
@@ -71,14 +72,14 @@ class ResolvingHost (object):
   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)
 
@@ -93,17 +94,19 @@ class ResolvingHost (object):
     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.
 
@@ -122,6 +125,35 @@ class BulkResolver (object):
   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):
@@ -132,20 +164,10 @@ class BulkResolver (object):
       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:
@@ -156,6 +178,9 @@ class BulkResolver (object):
     host._resolv = None
     me._noutstand -= 1
 
+## Select a bulk resolver.  Currently, there's only one choice.
+BulkResolver = BresBulkResolver
+
 ###--------------------------------------------------------------------------
 ### The configuration parser.
 
@@ -182,7 +207,7 @@ RX_REF = RX.compile(r'(?x) \$ \( ([^)]+) \)')
 
 ## 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):
@@ -401,8 +426,9 @@ class MyConfigParser (object):
       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.