Merge pull request #13 from agaridata/master

Upgrade libudns to 0.4 and add NS record lookup support.

README.markdown

@@ -5,7 +5,7 @@
 
 ## Overview
 
-EM-Udns is an async DNS resolver for [EventMachine](http://rubyeventmachine.com) based on [udns](http://www.corpit.ru/mjt/udns.html) C library. Having most of the code written in C, EM-Udns becomes very fast. It can resolve DNS A, AAAA, PTR, MX, TXT, SRV and NAPTR records, and can handle every kind of errors (domain/record not found, request timeout, malformed response...).
+EM-Udns is an async DNS resolver for [EventMachine](http://rubyeventmachine.com) based on [udns](http://www.corpit.ru/mjt/udns.html) C library. Having most of the code written in C, EM-Udns becomes very fast. It can resolve DNS A, AAAA, PTR, MX, TXT, NS, SRV and NAPTR records, and can handle every kind of errors (domain/record not found, request timeout, malformed response...).
 
 C udns is a stub resolver, so also EM-Udns. This means that it must rely on a recursive name server, usually co-located in local host or local network. A very good choice is [Unbound](http://unbound.net), a validating, recursive and caching DNS resolver.
 
@@ -21,6 +21,11 @@ C udns is a stub resolver, so also EM-Udns. This means that it must rely on a re
       EM::Udns.nameservers = "127.0.0.1"
       
       resolver = EM::Udns::Resolver.new
+
+      # alternate method of setting nameserver, including non-standard port
+      # resolver = EM::Udns::Resolver.new(nameserver: '127.0.0.1:5353')
+      # resolver = EM::Udns::Resolver.new(nameserver: ['192.168.0.1', '192.168.0.2:5353'])
+
       EM::Udns.run resolver
 
       query = resolver.submit_A "google.com"
@@ -67,8 +72,12 @@ Example 2:
 
 Returns a `EM::Udns::Resolver` instance. If there is an error an exception `EM::Udns::UdnsError` is raised.
 
-
-## Runnig a Resolver
+    nameserver(s) may also be passed to `new` as a hash argument:
+
+    resolver = EM::Udns::Resolver.new(nameserver: '127.0.0.1:5353')
+    resolver = EM::Udns::Resolver.new(nameserver: ['192.168.0.1', '192.168.0.2:5353'])
+
+## Running a Resolver
 
     EM::Udns.run resolver
 
@@ -194,6 +203,21 @@ Callback is called with argument:
 
     ["v=spf1 redirect=_spf.google.com"]
 
+
+### NS Record
+
+    resolver.submit_NS(domain)
+
+In case of success the callback is invoked passing as argument an array of `String` objects.  Each `String`  represents a nameserver entry in the NS result.
+
+Example:
+
+    resolver.submit_NS "gmail.com"
+
+Callback is called with argument:
+
+    ["ns1.google.com", "ns3.google.com", "ns4.google.com", "ns2.google.com"]
+
 
 ### SRV Record
 

em-udns.gemspec

@@ -22,7 +22,7 @@ Gem::Specification.new do |spec|
     ext/em-udns.c
     ext/em-udns.h
     ext/extconf.rb
-    ext/udns-0.2-patched.tar.gz
+    ext/udns-0.4-patched.tar.gz
     test/test-em-udns.rb
   }
   spec.require_paths = ["lib"]

ext/em-udns.c

@@ -2,6 +2,8 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
 #include "udns.h"
 #include "em-udns.h"
 
@@ -141,8 +143,7 @@ VALUE Resolver_timeouts(VALUE self)
 VALUE Resolver_cancel(VALUE self, VALUE query)
 {
   VALUE queries;
-  VALUE value;
-
+
   queries = rb_ivar_get(self, id_queries);
   if (TYPE(rb_hash_aref(queries, query)) == T_TRUE) {
     rb_hash_aset(queries, query, Qfalse);
@@ -261,7 +262,7 @@ static void dns_result_PTR_cb(struct dns_ctx *dns_context, struct dns_rr_ptr *rr
   for(i = 0; i < rr->dnsptr_nrr; i++)
     rb_ary_push(array, rb_str_new2(rr->dnsptr_ptr[i]));
   free(rr);
-  
+
   rb_funcall(query, method_do_success, 1, array);
 }
 
@@ -287,6 +288,24 @@ static void dns_result_MX_cb(struct dns_ctx *dns_context, struct dns_rr_mx *rr,
   rb_funcall(query, method_do_success, 1, array);
 }
 
+static void dns_result_NS_cb(struct dns_ctx *dns_context, struct dns_rr_ns *rr, void *data)
+{
+  VALUE query;
+  VALUE array;
+  int i;
+
+  if (!(query = (VALUE)check_query(dns_context, rr, data))) return;
+
+  array = rb_ary_new2(rr->dnsns_nrr);
+  for(i = 0; i < rr->dnsns_nrr; i++) {
+    rb_ary_push(array, rb_str_new2(rr->dnsns_ns[i]));
+  }
+  free(rr);
+
+  rb_funcall(query, method_do_success, 1, array);
+}
+
+
 
 static void dns_result_TXT_cb(struct dns_ctx *dns_context, struct dns_rr_txt *rr, void *data)
 {
@@ -298,7 +317,7 @@ static void dns_result_TXT_cb(struct dns_ctx *dns_context, struct dns_rr_txt *rr
 
   array = rb_ary_new2(rr->dnstxt_nrr);
   for(i = 0; i < rr->dnstxt_nrr; i++)
-    rb_ary_push(array, rb_str_new(rr->dnstxt_txt[i].txt, rr->dnstxt_txt[i].len));
+    rb_ary_push(array, rb_str_new((const char*)rr->dnstxt_txt[i].txt, rr->dnstxt_txt[i].len));
   free(rr);
 
   rb_funcall(query, method_do_success, 1, array);
@@ -524,6 +543,33 @@ VALUE Resolver_submit_MX(VALUE self, VALUE rb_domain)
   return query;
 }
 
+VALUE Resolver_submit_NS(VALUE self, VALUE rb_domain)
+{
+  struct dns_ctx *dns_context;
+  char *domain;
+  VALUE query;
+  VALUE error;
+  struct resolver_query *data;
+
+  Data_Get_Struct(self, struct dns_ctx, dns_context);
+  domain = StringValueCStr(rb_domain);
+  query = rb_obj_alloc(cQuery);
+
+  data = ALLOC(struct resolver_query);
+  data->resolver = self;
+  data-> query = query;
+
+  if (!dns_submit_ns(dns_context, domain, 0, dns_result_NS_cb, (void *)data)) {
+    error = get_dns_error(dns_context);
+    xfree(data);
+    rb_funcall(query, method_do_error, 1, error);
+  }
+  else {
+    rb_hash_aset(rb_ivar_get(self, id_queries), query, Qtrue);
+  }
+  return query;
+}
+
 
 VALUE Resolver_submit_TXT(VALUE self, VALUE rb_domain)
 {
@@ -624,6 +670,36 @@ VALUE Resolver_submit_NAPTR(VALUE self, VALUE rb_domain)
   return query;
 }
 
+int _add_serv_s(struct dns_ctx *dns_context, const char *ip, in_port_t port)
+{
+  struct sockaddr_in server_addr;
+  server_addr.sin_family = AF_INET;
+  inet_aton(ip, &server_addr.sin_addr);
+  server_addr.sin_port = htons(port);
+  return dns_add_serv_s(dns_context, (struct sockaddr *)&server_addr);
+}
+
+VALUE Resolver_add_serv(VALUE self, VALUE ip)
+{
+  struct dns_ctx *dns_context;
+  struct servent *sp;
+
+  Data_Get_Struct(self, struct dns_ctx, dns_context);
+
+  if (TYPE(ip) == T_NIL) {
+    return INT2FIX(dns_add_serv(dns_context, NULL));
+  }
+
+  sp = getservbyname("domain", "udp");
+  return INT2FIX(_add_serv_s(dns_context, StringValueCStr(ip), htons(sp->s_port)));
+}
+
+VALUE Resolver_add_serv_s(VALUE self, VALUE ip, VALUE port)
+{
+  struct dns_ctx *dns_context;
+  Data_Get_Struct(self, struct dns_ctx, dns_context);
+  return INT2FIX(_add_serv_s(dns_context, StringValueCStr(ip), FIX2INT(port)));
+}
 
 /* Attribute readers. */
 VALUE RR_MX_domain(VALUE self)          { return rb_ivar_get(self, id_domain); }
@@ -663,6 +739,9 @@ void Init_em_udns_ext()
   rb_define_method(cResolver, "submit_TXT", Resolver_submit_TXT, 1);
   rb_define_method(cResolver, "submit_SRV", Resolver_submit_SRV, -1);
   rb_define_method(cResolver, "submit_NAPTR", Resolver_submit_NAPTR, 1);
+  rb_define_method(cResolver, "submit_NS", Resolver_submit_NS, 1);
+  rb_define_method(cResolver, "add_serv", Resolver_add_serv, 1);
+  rb_define_method(cResolver, "add_serv_s", Resolver_add_serv_s, 2);
 
   cQuery = rb_define_class_under(mUdns, "Query", rb_cObject);
 

lib/em-udns/resolver.rb

@@ -1,9 +1,21 @@
 module EventMachine::Udns
 
   class Resolver
-    def initialize
+    def initialize(options = {})
       raise UdnsError, @alloc_error if @alloc_error
       @queries = {}
+      nameservers = [*options[:nameserver]] + [*options[:nameservers]]
+      if nameservers.any?
+        add_serv(nil) # clear the list initialized from /etc/resolv.conf
+        nameservers.each do |ns|
+          host, port = ns.split(':')
+          if port
+            add_serv_s(host, port.to_i)
+          else
+            add_serv(host)
+          end
+        end
+      end
       dns_open
     end
 
@@ -15,4 +27,4 @@ def set_timer(timeout)
     end
   end
 
-end
+end

lib/em-udns/version.rb

@@ -1,5 +1,5 @@
 module EventMachine
   module Udns
-    VERSION = "0.3.6"
+    VERSION = "0.3.6.2"
   end
 end

test/test-em-udns.rb

@@ -18,6 +18,7 @@ def show_usage
   #{$0} SRV _service._protocol.domain [times]
   #{$0} SRV domain [service] [protocol] [times]
   #{$0} NAPTR domain [times]
+  #{$0} NS domain [times]
 END_USAGE
 end
 
@@ -30,7 +31,7 @@ def show_usage
 type = ARGV[0].upcase
 name = ARGV[1]
 case type
-when "A", "AAAA", "MX", "TXT", "PTR", "NAPTR"
+when "A", "AAAA", "MX", "TXT", "PTR", "NAPTR", "NS"
   times = (ARGV[2].to_i > 0) ? ARGV[2].to_i : 1
 when "SRV"
   if ARGV[3]
@@ -92,6 +93,8 @@ def print_info(times, time_start)
           resolver.submit_SRV name, service, protocol
         when "NAPTR"
           resolver.submit_NAPTR name
+        when "NS"
+          resolver.submit_NS name
       end
 
       query.callback do |result|