From 97567475d4a5cd2860df6aeac5cef30be4342da6 Mon Sep 17 00:00:00 2001
Message-Id: <97567475d4a5cd2860df6aeac5cef30be4342da6.1719076106.git.mdw@distorted.org.uk>
From: Mark Wooding <mdw@chiark.greenend.org.uk>
Date: Wed, 27 Sep 2017 09:07:20 +0100
Subject: [PATCH] peerdb/tripe-newpeers.in: Add support for v4 and v6 address
 literals.
Organization: Straylight/Edgeware

From: Mark Wooding <mdw@distorted.org.uk>

At least they get canonified now.  I think v4 literals should have
worked before, but it seems that they didn't.  This adds a `6' flag to
request only the v6 addresses for a name, but currently you can predict
which addresses you get pretty well.
---
 peerdb/peers.in.5.in     | 12 +++++++++++-
 peerdb/tripe-newpeers.in | 26 +++++++++++++++++++-------
 2 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/peerdb/peers.in.5.in b/peerdb/peers.in.5.in
index 4e6d5cad..6aa8ffca 100644
--- a/peerdb/peers.in.5.in
+++ b/peerdb/peers.in.5.in
@@ -97,9 +97,19 @@ consist of zero or more of the following characters:
 looks up the
 .IR host 's
 IPv4 address(es);
+.RB ` 6 '
+looks up the
+.IR host 's
+IPv6 address(es);
+and
 .RB ` * '
 returns all of the found addresses, separated by spaces, rather than
-just the first one.
+just the first one.  If neither address family is requested, then
+.RB ` 46 '
+is assumed.  Currently,
+.BR tripe-newpeers(8)
+can only resolve hostnames to IPv4 addresses, but it can `resolve'
+numeric addresses of either kind.
 .PP
 There is a simple concept of
 .I inheritance
diff --git a/peerdb/tripe-newpeers.in b/peerdb/tripe-newpeers.in
index 44761972..5f33f5bd 100644
--- 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)
 
@@ -93,12 +94,14 @@ 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
@@ -136,7 +139,15 @@ class BulkResolver (object):
     """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)
+      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 run(me):
     """Run the background DNS resolver until it's finished."""
@@ -182,7 +193,7 @@ 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 +412,9 @@ 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.
 
-- 
[mdw]