On 17.10.2012 02:55, Gustavo Luiz Duarte wrote: > > 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); Here you don't handle error conditions in called functions. > + 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; In this and many other places in this patch you return error value without using grub_error. > + 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, >
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