Attachment 628205 Details for Bug 860829 – [PATCH] Issue separate DNS queries for ipv4 and ipv6

[PATCH] Issue separate DNS queries for ipv4 and ipv6

0001-Issue-separate-DNS-queries-for-ipv4-and-ipv6.patch (text/plain), 7.45 KB, created by IBM Bug Proxy on 2012-10-16 15:01:48 UTC

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Creator: IBM Bug Proxy

Created: 2012-10-16 15:01:48 UTC

Size: 7.45 KB

patch

obsolete

>From 3e00d82827f80461f9fe6da37acd84235c08e5a5 Mon Sep 17 00:00:00 2001
>From: Gustavo Luiz Duarte <gustavold@linux.vnet.ibm.com>
>Date: Fri, 28 Sep 2012 19:42:07 -0400
>Subject: [PATCH] Issue separate DNS queries for ipv4 and ipv6
>
>Adding multiple questions on a single DNS query is not supportted by
>most DNS servers. This patch issues two separate DNS queries
>sequentially for ipv4 and then for ipv6.
>
>There are 4 possible config options:
> DNS_OPTION_IPV4: issue only one ipv4 query
> DNS_OPTION_IPV6: issue only one ipv6 query
> DNS_OPTION_PREFER_IPV4: issue the ipv4 query first and fallback to ipv6
> DNS_OPTION_PREFER_IPV6: issue the ipv6 query first and fallback to ipv4
>However, there is no code yet to set such config option. The default is
>DNS_OPTION_PREFER_IPV4.
>
>Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=860829
>---
> grub-core/net/dns.c | 99 ++++++++++++++++++++++++++++++++++++-----------------
> include/grub/net.h  |  9 +++++
> 2 files changed, 76 insertions(+), 32 deletions(-)
>
>diff --git a/grub-core/net/dns.c b/grub-core/net/dns.c
>index 3381ea7..725725c 100644
>--- a/grub-core/net/dns.c
>+++ b/grub-core/net/dns.c
>@@ -34,6 +34,14 @@ struct dns_cache_element
> #define DNS_CACHE_SIZE 1021
> #define DNS_HASH_BASE 423
> 
>+typedef enum grub_dns_qtype_id
>+  {
>+    GRUB_DNS_QTYPE_A = 1,
>+    GRUB_DNS_QTYPE_AAAA = 28
>+  } grub_dns_qtype_id_t;
>+
>+static grub_dns_option_t dns_type_option = DNS_OPTION_PREFER_IPV4;
>+
> static struct dns_cache_element dns_cache[DNS_CACHE_SIZE];
> static struct grub_net_network_level_address *dns_servers;
> static grub_size_t dns_nservers, dns_servers_alloc;
>@@ -410,13 +418,13 @@ recv_hook (grub_net_udp_socket_t sock __attribute__ ((unused)),
>   return GRUB_ERR_NONE;
> }
> 
>-grub_err_t
>-grub_net_dns_lookup (const char *name,
>+static grub_err_t
>+grub_net_dns_lookup_qtype (const char *name,
> 		     const struct grub_net_network_level_address *servers,
> 		     grub_size_t n_servers,
> 		     grub_size_t *naddresses,
> 		     struct grub_net_network_level_address **addresses,
>-		     int cache)
>+		     int cache, grub_dns_qtype_id_t qtype)
> {
>   grub_size_t send_servers = 0;
>   grub_size_t i, j;
>@@ -471,8 +479,7 @@ grub_net_dns_lookup (const char *name,
> 			   + GRUB_NET_MAX_LINK_HEADER_SIZE
> 			   + GRUB_NET_UDP_HEADER_SIZE
> 			   + sizeof (struct dns_header)
>-			   + grub_strlen (name) + 2 + 4
>-			   + 2 + 4);
>+			   + grub_strlen (name) + 2 + 4);
>   if (!nb)
>     {
>       grub_free (data.name);
>@@ -482,7 +489,7 @@ grub_net_dns_lookup (const char *name,
> 			+ GRUB_NET_MAX_LINK_HEADER_SIZE
> 			+ GRUB_NET_UDP_HEADER_SIZE);
>   grub_netbuff_put (nb, sizeof (struct dns_header)
>-		    + grub_strlen (name) + 2 + 4 + 2 + 4);
>+		    + grub_strlen (name) + 2 + 4);
>   head = (struct dns_header *) nb->data;
>   optr = (grub_uint8_t *) (head + 1);
>   for (iptr = name; *iptr; )
>@@ -509,18 +516,7 @@ grub_net_dns_lookup (const char *name,
> 
>   /* Type: A.  */
>   *optr++ = 0;
>-  *optr++ = 1;
>-
>-  /* Class.  */
>-  *optr++ = 0;
>-  *optr++ = 1;
>-
>-  /* Compressed name.  */
>-  *optr++ = 0xc0;
>-  *optr++ = 0x0c;
>-  /* Type: AAAA.  */
>-  *optr++ = 0;
>-  *optr++ = 28;
>+  *optr++ = qtype;
> 
>   /* Class.  */
>   *optr++ = 0;
>@@ -529,7 +525,7 @@ grub_net_dns_lookup (const char *name,
>   head->id = data.id;
>   head->flags = FLAGS_RD;
>   head->ra_z_r_code = 0;
>-  head->qdcount = grub_cpu_to_be16_compile_time (2);
>+  head->qdcount = grub_cpu_to_be16_compile_time (1);
>   head->ancount = grub_cpu_to_be16_compile_time (0);
>   head->nscount = grub_cpu_to_be16_compile_time (0);
>   head->arcount = grub_cpu_to_be16_compile_time (0);
>@@ -587,16 +583,47 @@ grub_net_dns_lookup (const char *name,
>   if (*data.naddresses)
>     return GRUB_ERR_NONE;
>   if (data.dns_err)
>-    return grub_error (GRUB_ERR_NET_NO_DOMAIN,
>-		       N_("no DNS record found"));
>-    
>+    {
>+      grub_dprintf ("dns", "%s. QTYPE: %u QNAME: %s\n",
>+                    N_("no DNS record found"), qtype, name);
>+      return GRUB_ERR_NET_NO_DOMAIN;
>+    }
>   if (err)
>     {
>       grub_errno = err;
>       return err;
>     }
>-  return grub_error (GRUB_ERR_TIMEOUT,
>-		     N_("no DNS reply received"));
>+  grub_dprintf ("dns", "%s. QTYPE: %u QNAME: %s\n",
>+                N_("no DNS reply received"), qtype, name);
>+  return GRUB_ERR_TIMEOUT;
>+}
>+
>+grub_err_t
>+grub_net_dns_lookup (const char *name,
>+		     const struct grub_net_network_level_address *servers,
>+		     grub_size_t n_servers,
>+		     grub_size_t *naddresses,
>+		     struct grub_net_network_level_address **addresses,
>+		     int cache)
>+{
>+  if (dns_type_option == DNS_OPTION_IPV6 || dns_type_option == DNS_OPTION_PREFER_IPV6)
>+      grub_net_dns_lookup_qtype (name, servers, n_servers, naddresses,
>+                                 addresses, cache, GRUB_DNS_QTYPE_AAAA);
>+  else
>+      grub_net_dns_lookup_qtype (name, servers, n_servers, naddresses,
>+                                 addresses, cache, GRUB_DNS_QTYPE_A);
>+  if (!*naddresses)
>+    {
>+      if (dns_type_option == DNS_OPTION_PREFER_IPV4)
>+          grub_net_dns_lookup_qtype (name, servers, n_servers, naddresses,
>+                                     addresses, cache, GRUB_DNS_QTYPE_AAAA);
>+      else if (dns_type_option == DNS_OPTION_PREFER_IPV6)
>+          grub_net_dns_lookup_qtype (name, servers, n_servers, naddresses,
>+                                     addresses, cache, GRUB_DNS_QTYPE_A);
>+    }
>+  if (!*naddresses)
>+      return GRUB_ERR_NET_NO_DOMAIN;
>+  return GRUB_ERR_NONE;
> }
> 
> static grub_err_t
>@@ -604,22 +631,28 @@ grub_cmd_nslookup (struct grub_command *cmd __attribute__ ((unused)),
> 		   int argc, char **args)
> {
>   grub_err_t err;
>-  grub_size_t naddresses, i;
>+  struct grub_net_network_level_address cmd_server;
>+  struct grub_net_network_level_address *servers;
>+  grub_size_t nservers, i, naddresses = 0;
>   struct grub_net_network_level_address *addresses = 0;
>   if (argc != 2 && argc != 1)
>     return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("two arguments expected"));
>   if (argc == 2)
>     {
>-      struct grub_net_network_level_address server;
>-      err = grub_net_resolve_address (args[1], &server);
>+      err = grub_net_resolve_address (args[1], &cmd_server);
>       if (err)
> 	return err;
>-      err = grub_net_dns_lookup (args[0], &server, 1, &naddresses,
>-				 &addresses, 0);
>+      servers = &cmd_server;
>+      nservers = 1;
>     }
>   else
>-    err = grub_net_dns_lookup (args[0], dns_servers, dns_nservers, &naddresses,
>-			       &addresses, 0);
>+    {
>+      servers = dns_servers;
>+      nservers = dns_nservers;
>+    }
>+
>+  grub_net_dns_lookup (args[0], servers, nservers, &naddresses,
>+                       &addresses, 0);
> 
>   for (i = 0; i < naddresses; i++)
>     {
>@@ -628,7 +661,9 @@ grub_cmd_nslookup (struct grub_command *cmd __attribute__ ((unused)),
>       grub_printf ("%s\n", buf);
>     }
>   grub_free (addresses);
>-  return GRUB_ERR_NONE;
>+  if (naddresses)
>+    return GRUB_ERR_NONE;
>+  return grub_error (GRUB_ERR_NET_NO_DOMAIN, N_("no DNS record found"));
> }
> 
> static grub_err_t
>diff --git a/include/grub/net.h b/include/grub/net.h
>index 3877451..a7e5b2c 100644
>--- a/include/grub/net.h
>+++ b/include/grub/net.h
>@@ -505,6 +505,15 @@ grub_err_t
> grub_net_link_layer_resolve (struct grub_net_network_level_interface *inf,
> 			     const grub_net_network_level_address_t *proto_addr,
> 			     grub_net_link_level_address_t *hw_addr);
>+
>+typedef enum
>+  {
>+    DNS_OPTION_IPV4,
>+    DNS_OPTION_IPV6,
>+    DNS_OPTION_PREFER_IPV4,
>+    DNS_OPTION_PREFER_IPV6
>+  } grub_dns_option_t;
>+
> grub_err_t
> grub_net_dns_lookup (const char *name,
> 		     const struct grub_net_network_level_address *servers,
>-- 
>1.7.11.4
>

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Attachments on bug 860829: 618761 | 628205