Merge pull request luvit#945 from n1tehawk/20170131_resolvebyip

dns: Add the ability to handle numeric addresses

deps/dns.lua

@@ -20,7 +20,7 @@ limitations under the License.
 -- https://github.com/openresty/lua-resty-dns/blob/master/lib/resty/dns/resolver.lua
 --[[lit-meta
   name = "luvit/dns"
-  version = "2.0.2"
+  version = "2.0.3"
   dependencies = {
     "luvit/[email protected]",
     "luvit/[email protected]",
@@ -51,6 +51,7 @@ local byte = string.byte
 local gsub = string.gsub
 local sub = string.sub
 local format = string.format
+local match = string.match
 local band = bit.band
 local bor = bit.bor
 local rshift = bit.rshift
@@ -604,6 +605,20 @@ local function parse_response(buf, id, server)
 end
 
 local function _query(servers, name, dnsclass, qtype, callback)
+
+  -- Try to resolve IPs directly, without contacting DNS servers
+  if (qtype == TYPE_A and match(name, "^%d+%.%d+%.%d+%.%d+$")) -- numeric IPv4
+     or (qtype == TYPE_AAAA and match(name, "^[:%x]+$")) -- hexadecimal IPv6
+  then
+    -- Answer query 'locally', by passing suitable arguments to the callback
+    -- function. This reports a single address result, with no (`nil`) name,
+    -- an empty "server" table and a TTL of 0.
+    callback(nil, {
+      {address = name, type = qtype, class = CLASS_IN, server = {}, ttl = 0}
+    })
+    return
+  end
+
   local tries, max_tries, server, tcp_iter, udp_iter, get_server_iter
 
   tries = 1

package.lua

@@ -25,7 +25,7 @@ return {
     "luvit/[email protected]",
     "luvit/[email protected]",
     "luvit/[email protected]",
-    "luvit/[email protected].2",
+    "luvit/[email protected].3",
     "luvit/[email protected]",
     "luvit/[email protected]",
     "luvit/[email protected]",

tests/test-dns.lua

@@ -31,15 +31,22 @@ require('tap')(function (test)
       p(answers)
     end))
   end)
+  test("resolve4ip", function (expect)
+    dns.resolve4('127.0.0.1', expect(function(err, answers)
+      assert(not err)
+      assert(#answers > 0)
+      p(answers)
+    end))
+  end)
   test("resolve6", function (expect)
     dns.resolve6('luvit.io', expect(function(err, answers)
       assert(not err)
       p(answers)
       assert(#answers > 0)
     end))
   end)
-  test("resolve6", function (expect)
-    dns.resolve6('luvit.io', expect(function(err, answers)
+  test("resolve6ip", function (expect)
+    dns.resolve6('::1', expect(function(err, answers)
       assert(not err)
       p(answers)
       assert(#answers > 0)