diff options
Diffstat (limited to '')
| -rw-r--r-- | external/unbound/dns64/dns64.c | 865 |
1 files changed, 865 insertions, 0 deletions
diff --git a/external/unbound/dns64/dns64.c b/external/unbound/dns64/dns64.c new file mode 100644 index 000000000..963e727fe --- /dev/null +++ b/external/unbound/dns64/dns64.c @@ -0,0 +1,865 @@ +/* + * dns64/dns64.c - DNS64 module + * + * Copyright (c) 2009, Viagénie. All rights reserved. + * + * This software is open source. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * Neither the name of Viagénie nor the names of its contributors may + * be used to endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +/** + * \file + * + * This file contains a module that performs DNS64 query processing. + */ + +#include "config.h" +#include "dns64/dns64.h" +#include "services/cache/dns.h" +#include "services/cache/rrset.h" +#include "util/config_file.h" +#include "util/data/msgreply.h" +#include "util/fptr_wlist.h" +#include "util/net_help.h" +#include "util/regional.h" + +/****************************************************************************** + * * + * STATIC CONSTANTS * + * * + ******************************************************************************/ + +/** + * This is the default DNS64 prefix that is used whent he dns64 module is listed + * in module-config but when the dns64-prefix variable is not present. + */ +static const char DEFAULT_DNS64_PREFIX[] = "64:ff9b::/96"; + +/** + * Maximum length of a domain name in a PTR query in the .in-addr.arpa tree. + */ +#define MAX_PTR_QNAME_IPV4 30 + +/** + * Per-query module-specific state. This is usually a dynamically-allocated + * structure, but in our case we only need to store one variable describing the + * state the query is in. So we repurpose the minfo pointer by storing an + * integer in there. + */ +enum dns64_qstate { + DNS64_INTERNAL_QUERY, /**< Internally-generated query, no DNS64 + processing. */ + DNS64_NEW_QUERY, /**< Query for which we're the first module in + line. */ + DNS64_SUBQUERY_FINISHED /**< Query for which we generated a sub-query, and + for which this sub-query is finished. */ +}; + + +/****************************************************************************** + * * + * STRUCTURES * + * * + ******************************************************************************/ + +/** + * This structure contains module configuration information. One instance of + * this structure exists per instance of the module. Normally there is only one + * instance of the module. + */ +struct dns64_env { + /** + * DNS64 prefix address. We're using a full sockaddr instead of just an + * in6_addr because we can reuse Unbound's generic string parsing functions. + * It will always contain a sockaddr_in6, and only the sin6_addr member will + * ever be used. + */ + struct sockaddr_storage prefix_addr; + + /** + * This is always sizeof(sockaddr_in6). + */ + socklen_t prefix_addrlen; + + /** + * This is the CIDR length of the prefix. It needs to be between 0 and 96. + */ + int prefix_net; +}; + + +/****************************************************************************** + * * + * UTILITY FUNCTIONS * + * * + ******************************************************************************/ + +/** + * Generic macro for swapping two variables. + * + * \param t Type of the variables. (e.g. int) + * \param a First variable. + * \param b Second variable. + * + * \warning Do not attempt something foolish such as swap(int,a++,b++)! + */ +#define swap(t,a,b) do {t x = a; a = b; b = x;} while(0) + +/** + * Reverses a string. + * + * \param begin Points to the first character of the string. + * \param end Points one past the last character of the string. + */ +static void +reverse(char* begin, char* end) +{ + while ( begin < --end ) { + swap(char, *begin, *end); + ++begin; + } +} + +/** + * Convert an unsigned integer to a string. The point of this function is that + * of being faster than sprintf(). + * + * \param n The number to be converted. + * \param s The result will be written here. Must be large enough, be careful! + * + * \return The number of characters written. + */ +static int +uitoa(unsigned n, char* s) +{ + char* ss = s; + do { + *ss++ = '0' + n % 10; + } while (n /= 10); + reverse(s, ss); + return ss - s; +} + +/** + * Extract an IPv4 address embedded in the IPv6 address \a ipv6 at offset \a + * offset (in bits). Note that bits are not necessarily aligned on bytes so we + * need to be careful. + * + * \param ipv6 IPv6 address represented as a 128-bit array in big-endian + * order. + * \param offset Index of the MSB of the IPv4 address embedded in the IPv6 + * address. + */ +static uint32_t +extract_ipv4(const uint8_t ipv6[16], const int offset) +{ + uint32_t ipv4 = (uint32_t)ipv6[offset/8+0] << (24 + (offset%8)) + | (uint32_t)ipv6[offset/8+1] << (16 + (offset%8)) + | (uint32_t)ipv6[offset/8+2] << ( 8 + (offset%8)) + | (uint32_t)ipv6[offset/8+3] << ( 0 + (offset%8)); + if (offset/8+4 < 16) + ipv4 |= (uint32_t)ipv6[offset/8+4] >> (8 - offset%8); + return ipv4; +} + +/** + * Builds the PTR query name corresponding to an IPv4 address. For example, + * given the number 3,464,175,361, this will build the string + * "\03206\03123\0231\011\07in-addr\04arpa". + * + * \param ipv4 IPv4 address represented as an unsigned 32-bit number. + * \param ptr The result will be written here. Must be large enough, be + * careful! + * + * \return The number of characters written. + */ +static size_t +ipv4_to_ptr(uint32_t ipv4, char ptr[MAX_PTR_QNAME_IPV4]) +{ + static const char IPV4_PTR_SUFFIX[] = "\07in-addr\04arpa"; + int i; + char* c = ptr; + + for (i = 0; i < 4; ++i) { + *c = uitoa((unsigned int)(ipv4 % 256), c + 1); + c += *c + 1; + ipv4 /= 256; + } + + memmove(c, IPV4_PTR_SUFFIX, sizeof(IPV4_PTR_SUFFIX)); + + return c + sizeof(IPV4_PTR_SUFFIX) - ptr; +} + +/** + * Converts an IPv6-related domain name string from a PTR query into an IPv6 + * address represented as a 128-bit array. + * + * \param ptr The domain name. (e.g. "\011[...]\010\012\016\012\03ip6\04arpa") + * \param ipv6 The result will be written here, in network byte order. + * + * \return 1 on success, 0 on failure. + */ +static int +ptr_to_ipv6(const char* ptr, uint8_t ipv6[16]) +{ + int i; + + for (i = 0; i < 64; i++) { + int x; + + if (ptr[i++] != 1) + return 0; + + if (ptr[i] >= '0' && ptr[i] <= '9') { + x = ptr[i] - '0'; + } else if (ptr[i] >= 'a' && ptr[i] <= 'f') { + x = ptr[i] - 'a' + 10; + } else if (ptr[i] >= 'A' && ptr[i] <= 'F') { + x = ptr[i] - 'A' + 10; + } else { + return 0; + } + + ipv6[15-i/4] |= x << (2 * ((i-1) % 4)); + } + + return 1; +} + +/** + * Synthesize an IPv6 address based on an IPv4 address and the DNS64 prefix. + * + * \param prefix_addr DNS64 prefix address. + * \param prefix_net CIDR length of the DNS64 prefix. Must be between 0 and 96. + * \param a IPv4 address. + * \param aaaa IPv6 address. The result will be written here. + */ +static void +synthesize_aaaa(const uint8_t prefix_addr[16], int prefix_net, + const uint8_t a[4], uint8_t aaaa[16]) +{ + memcpy(aaaa, prefix_addr, 16); + aaaa[prefix_net/8+0] |= a[0] >> (0+prefix_net%8); + aaaa[prefix_net/8+1] |= a[0] << (8-prefix_net%8); + aaaa[prefix_net/8+1] |= a[1] >> (0+prefix_net%8); + aaaa[prefix_net/8+2] |= a[1] << (8-prefix_net%8); + aaaa[prefix_net/8+2] |= a[2] >> (0+prefix_net%8); + aaaa[prefix_net/8+3] |= a[2] << (8-prefix_net%8); + aaaa[prefix_net/8+3] |= a[3] >> (0+prefix_net%8); + if (prefix_net/8+4 < 16) /* <-- my beautiful symmetry is destroyed! */ + aaaa[prefix_net/8+4] |= a[3] << (8-prefix_net%8); +} + + +/****************************************************************************** + * * + * DNS64 MODULE FUNCTIONS * + * * + ******************************************************************************/ + +/** + * This function applies the configuration found in the parsed configuration + * file \a cfg to this instance of the dns64 module. Currently only the DNS64 + * prefix (a.k.a. Pref64) is configurable. + * + * \param dns64_env Module-specific global parameters. + * \param cfg Parsed configuration file. + */ +static int +dns64_apply_cfg(struct dns64_env* dns64_env, struct config_file* cfg) +{ + verbose(VERB_ALGO, "dns64-prefix: %s", cfg->dns64_prefix); + if (!netblockstrtoaddr(cfg->dns64_prefix ? cfg->dns64_prefix : + DEFAULT_DNS64_PREFIX, 0, &dns64_env->prefix_addr, + &dns64_env->prefix_addrlen, &dns64_env->prefix_net)) { + log_err("cannot parse dns64-prefix netblock: %s", cfg->dns64_prefix); + return 0; + } + if (!addr_is_ip6(&dns64_env->prefix_addr, dns64_env->prefix_addrlen)) { + log_err("dns64_prefix is not IPv6: %s", cfg->dns64_prefix); + return 0; + } + if (dns64_env->prefix_net < 0 || dns64_env->prefix_net > 96) { + log_err("dns64-prefix length it not between 0 and 96: %s", + cfg->dns64_prefix); + return 0; + } + return 1; +} + +/** + * Initializes this instance of the dns64 module. + * + * \param env Global state of all module instances. + * \param id This instance's ID number. + */ +int +dns64_init(struct module_env* env, int id) +{ + struct dns64_env* dns64_env = + (struct dns64_env*)calloc(1, sizeof(struct dns64_env)); + if (!dns64_env) { + log_err("malloc failure"); + return 0; + } + env->modinfo[id] = (void*)dns64_env; + if (!dns64_apply_cfg(dns64_env, env->cfg)) { + log_err("dns64: could not apply configuration settings."); + return 0; + } + return 1; +} + +/** + * Deinitializes this instance of the dns64 module. + * + * \param env Global state of all module instances. + * \param id This instance's ID number. + */ +void +dns64_deinit(struct module_env* env, int id) +{ + if (!env) + return; + free(env->modinfo[id]); + env->modinfo[id] = NULL; +} + +/** + * Handle PTR queries for IPv6 addresses. If the address belongs to the DNS64 + * prefix, we must do a PTR query for the corresponding IPv4 address instead. + * + * \param qstate Query state structure. + * \param id This module instance's ID number. + * + * \return The new state of the query. + */ +static enum module_ext_state +handle_ipv6_ptr(struct module_qstate* qstate, int id) +{ + struct dns64_env* dns64_env = (struct dns64_env*)qstate->env->modinfo[id]; + struct module_qstate* subq = NULL; + struct query_info qinfo; + struct sockaddr_in6 sin6; + + /* Convert the PTR query string to an IPv6 address. */ + memset(&sin6, 0, sizeof(sin6)); + sin6.sin6_family = AF_INET6; + if (!ptr_to_ipv6((char*)qstate->qinfo.qname, sin6.sin6_addr.s6_addr)) + return module_wait_module; /* Let other module handle this. */ + + /* + * If this IPv6 address is not part of our DNS64 prefix, then we don't need + * to do anything. Let another module handle the query. + */ + if (addr_in_common((struct sockaddr_storage*)&sin6, 128, + &dns64_env->prefix_addr, dns64_env->prefix_net, + (socklen_t)sizeof(sin6)) != dns64_env->prefix_net) + return module_wait_module; + + verbose(VERB_ALGO, "dns64: rewrite PTR record"); + + /* + * Create a new PTR query info for the domain name corresponding to the IPv4 + * address corresponding to the IPv6 address corresponding to the original + * PTR query domain name. + */ + qinfo = qstate->qinfo; + if (!(qinfo.qname = regional_alloc(qstate->region, MAX_PTR_QNAME_IPV4))) + return module_error; + qinfo.qname_len = ipv4_to_ptr(extract_ipv4(sin6.sin6_addr.s6_addr, + dns64_env->prefix_net), (char*)qinfo.qname); + + /* Create the new sub-query. */ + fptr_ok(fptr_whitelist_modenv_attach_sub(qstate->env->attach_sub)); + if(!(*qstate->env->attach_sub)(qstate, &qinfo, qstate->query_flags, 0, + &subq)) + return module_error; + if (subq) { + subq->curmod = id; + subq->ext_state[id] = module_state_initial; + subq->minfo[id] = NULL; + } + + return module_wait_subquery; +} + +/** allocate (special) rrset keys, return 0 on error */ +static int +repinfo_alloc_rrset_keys(struct reply_info* rep, + struct regional* region) +{ + size_t i; + for(i=0; i<rep->rrset_count; i++) { + if(region) { + rep->rrsets[i] = (struct ub_packed_rrset_key*) + regional_alloc(region, + sizeof(struct ub_packed_rrset_key)); + if(rep->rrsets[i]) { + memset(rep->rrsets[i], 0, + sizeof(struct ub_packed_rrset_key)); + rep->rrsets[i]->entry.key = rep->rrsets[i]; + } + } + else return 0;/* rep->rrsets[i] = alloc_special_obtain(alloc);*/ + if(!rep->rrsets[i]) + return 0; + rep->rrsets[i]->entry.data = NULL; + } + return 1; +} + +static enum module_ext_state +generate_type_A_query(struct module_qstate* qstate, int id) +{ + struct module_qstate* subq = NULL; + struct query_info qinfo; + + verbose(VERB_ALGO, "dns64: query A record"); + + /* Create a new query info. */ + qinfo = qstate->qinfo; + qinfo.qtype = LDNS_RR_TYPE_A; + + /* Start the sub-query. */ + fptr_ok(fptr_whitelist_modenv_attach_sub(qstate->env->attach_sub)); + if(!(*qstate->env->attach_sub)(qstate, &qinfo, qstate->query_flags, 0, + &subq)) + { + verbose(VERB_ALGO, "dns64: sub-query creation failed"); + return module_error; + } + if (subq) { + subq->curmod = id; + subq->ext_state[id] = module_state_initial; + subq->minfo[id] = NULL; + } + + return module_wait_subquery; +} + +/** + * Handles the "pass" event for a query. This event is received when a new query + * is received by this module. The query may have been generated internally by + * another module, in which case we don't want to do any special processing + * (this is an interesting discussion topic), or it may be brand new, e.g. + * received over a socket, in which case we do want to apply DNS64 processing. + * + * \param qstate A structure representing the state of the query that has just + * received the "pass" event. + * \param id This module's instance ID. + * + * \return The new state of the query. + */ +static enum module_ext_state +handle_event_pass(struct module_qstate* qstate, int id) +{ + if ((uintptr_t)qstate->minfo[id] == DNS64_NEW_QUERY + && qstate->qinfo.qtype == LDNS_RR_TYPE_PTR + && qstate->qinfo.qname_len == 74 + && !strcmp((char*)&qstate->qinfo.qname[64], "\03ip6\04arpa")) + /* Handle PTR queries for IPv6 addresses. */ + return handle_ipv6_ptr(qstate, id); + + if (qstate->env->cfg->dns64_synthall && + (uintptr_t)qstate->minfo[id] == DNS64_NEW_QUERY + && qstate->qinfo.qtype == LDNS_RR_TYPE_AAAA) + return generate_type_A_query(qstate, id); + + /* We are finished when our sub-query is finished. */ + if ((uintptr_t)qstate->minfo[id] == DNS64_SUBQUERY_FINISHED) + return module_finished; + + /* Otherwise, pass request to next module. */ + verbose(VERB_ALGO, "dns64: pass to next module"); + return module_wait_module; +} + +/** + * Handles the "done" event for a query. We need to analyze the response and + * maybe issue a new sub-query for the A record. + * + * \param qstate A structure representing the state of the query that has just + * received the "pass" event. + * \param id This module's instance ID. + * + * \return The new state of the query. + */ +static enum module_ext_state +handle_event_moddone(struct module_qstate* qstate, int id) +{ + /* + * In many cases we have nothing special to do. From most to least common: + * + * - An internal query. + * - A query for a record type other than AAAA. + * - An AAAA query for which an error was returned. + * - A successful AAAA query with an answer. + */ + if ( (enum dns64_qstate)qstate->minfo[id] == DNS64_INTERNAL_QUERY + || qstate->qinfo.qtype != LDNS_RR_TYPE_AAAA + || qstate->return_rcode != LDNS_RCODE_NOERROR + || (qstate->return_msg && + qstate->return_msg->rep && + reply_find_answer_rrset(&qstate->qinfo, + qstate->return_msg->rep))) + return module_finished; + + /* So, this is a AAAA noerror/nodata answer */ + return generate_type_A_query(qstate, id); +} + +/** + * This is the module's main() function. It gets called each time a query + * receives an event which we may need to handle. We respond by updating the + * state of the query. + * + * \param qstate Structure containing the state of the query. + * \param event Event that has just been received. + * \param id This module's instance ID. + * \param outbound State of a DNS query on an authoritative server. We never do + * our own queries ourselves (other modules do it for us), so + * this is unused. + */ +void +dns64_operate(struct module_qstate* qstate, enum module_ev event, int id, + struct outbound_entry* outbound) +{ + (void)outbound; + verbose(VERB_QUERY, "dns64[module %d] operate: extstate:%s event:%s", + id, strextstate(qstate->ext_state[id]), + strmodulevent(event)); + log_query_info(VERB_QUERY, "dns64 operate: query", &qstate->qinfo); + + switch(event) { + case module_event_new: + /* Tag this query as being new and fall through. */ + qstate->minfo[id] = (void*)DNS64_NEW_QUERY; + case module_event_pass: + qstate->ext_state[id] = handle_event_pass(qstate, id); + break; + case module_event_moddone: + qstate->ext_state[id] = handle_event_moddone(qstate, id); + break; + default: + qstate->ext_state[id] = module_finished; + break; + } +} + +static void +dns64_synth_aaaa_data(const struct ub_packed_rrset_key* fk, + const struct packed_rrset_data* fd, + struct ub_packed_rrset_key *dk, + struct packed_rrset_data **dd_out, struct regional *region, + struct dns64_env* dns64_env ) +{ + struct packed_rrset_data *dd; + size_t i; + /* + * Create synthesized AAAA RR set data. We need to allocated extra memory + * for the RRs themselves. Each RR has a length, TTL, pointer to wireformat + * data, 2 bytes of data length, and 16 bytes of IPv6 address. + */ + if (!(dd = *dd_out = regional_alloc(region, + sizeof(struct packed_rrset_data) + + fd->count * (sizeof(size_t) + sizeof(time_t) + + sizeof(uint8_t*) + 2 + 16)))) { + log_err("out of memory"); + return; + } + + /* Copy attributes from A RR set. */ + dd->ttl = fd->ttl; + dd->count = fd->count; + dd->rrsig_count = 0; + dd->trust = fd->trust; + dd->security = fd->security; + + /* + * Synthesize AAAA records. Adjust pointers in structure. + */ + dd->rr_len = + (size_t*)((uint8_t*)dd + sizeof(struct packed_rrset_data)); + dd->rr_data = (uint8_t**)&dd->rr_len[dd->count]; + dd->rr_ttl = (time_t*)&dd->rr_data[dd->count]; + for(i = 0; i < fd->count; ++i) { + if (fd->rr_len[i] != 6 || fd->rr_data[i][0] != 0 + || fd->rr_data[i][1] != 4) + return; + dd->rr_len[i] = 18; + dd->rr_data[i] = + (uint8_t*)&dd->rr_ttl[dd->count] + 18*i; + dd->rr_data[i][0] = 0; + dd->rr_data[i][1] = 16; + synthesize_aaaa( + ((struct sockaddr_in6*)&dns64_env->prefix_addr)->sin6_addr.s6_addr, + dns64_env->prefix_net, &fd->rr_data[i][2], + &dd->rr_data[i][2] ); + dd->rr_ttl[i] = fd->rr_ttl[i]; + } + + /* + * Create synthesized AAAA RR set key. This is mostly just bookkeeping, + * nothing interesting here. + */ + if(!dk) { + log_err("no key"); + return; + } + + dk->rk.dname = (uint8_t*)regional_alloc_init(region, + fk->rk.dname, fk->rk.dname_len); + + if(!dk->rk.dname) { + log_err("out of memory"); + return; + } + + dk->rk.type = htons(LDNS_RR_TYPE_AAAA); + memset(&dk->entry, 0, sizeof(dk->entry)); + dk->entry.key = dk; + dk->entry.hash = rrset_key_hash(&dk->rk); + dk->entry.data = dd; + +} + +/** + * Synthesize an AAAA RR set from an A sub-query's answer and add it to the + * original empty response. + * + * \param id This module's instance ID. + * \param super Original AAAA query. + * \param qstate A query. + */ +static void +dns64_adjust_a(int id, struct module_qstate* super, struct module_qstate* qstate) +{ + struct dns64_env* dns64_env = (struct dns64_env*)super->env->modinfo[id]; + struct reply_info *rep, *cp; + size_t i, s; + struct packed_rrset_data* fd, *dd; + struct ub_packed_rrset_key* fk, *dk; + + verbose(VERB_ALGO, "converting A answers to AAAA answers"); + + log_assert(super->region); + log_assert(qstate->return_msg); + log_assert(qstate->return_msg->rep); + + /* If dns64-synthall is enabled, return_msg is not initialized */ + if(!super->return_msg) { + super->return_msg = (struct dns_msg*)regional_alloc( + super->region, sizeof(struct dns_msg)); + if(!super->return_msg) + return; + memset(super->return_msg, 0, sizeof(*super->return_msg)); + super->return_msg->qinfo = super->qinfo; + } + + rep = qstate->return_msg->rep; + + /* + * Build the actual reply. + */ + cp = construct_reply_info_base(super->region, rep->flags, rep->qdcount, + rep->ttl, rep->prefetch_ttl, rep->an_numrrsets, rep->ns_numrrsets, + rep->ar_numrrsets, rep->rrset_count, rep->security); + if(!cp) + return; + + /* allocate ub_key structures special or not */ + if(!repinfo_alloc_rrset_keys(cp, super->region)) { + return; + } + + /* copy everything and replace A by AAAA */ + for(i=0; i<cp->rrset_count; i++) { + fk = rep->rrsets[i]; + dk = cp->rrsets[i]; + fd = (struct packed_rrset_data*)fk->entry.data; + dk->rk = fk->rk; + dk->id = fk->id; + + if(i<rep->an_numrrsets && fk->rk.type == htons(LDNS_RR_TYPE_A)) { + /* also sets dk->entry.hash */ + dns64_synth_aaaa_data(fk, fd, dk, &dd, super->region, dns64_env); + /* Delete negative AAAA record from cache stored by + * the iterator module */ + rrset_cache_remove(super->env->rrset_cache, dk->rk.dname, + dk->rk.dname_len, LDNS_RR_TYPE_AAAA, + LDNS_RR_CLASS_IN, 0); + } else { + dk->entry.hash = fk->entry.hash; + dk->rk.dname = (uint8_t*)regional_alloc_init(super->region, + fk->rk.dname, fk->rk.dname_len); + + if(!dk->rk.dname) + return; + + s = packed_rrset_sizeof(fd); + dd = (struct packed_rrset_data*)regional_alloc_init( + super->region, fd, s); + + if(!dd) + return; + } + + packed_rrset_ptr_fixup(dd); + dk->entry.data = (void*)dd; + } + + /* Commit changes. */ + super->return_msg->rep = cp; +} + +/** + * Generate a response for the original IPv6 PTR query based on an IPv4 PTR + * sub-query's response. + * + * \param qstate IPv4 PTR sub-query. + * \param super Original IPv6 PTR query. + */ +static void +dns64_adjust_ptr(struct module_qstate* qstate, struct module_qstate* super) +{ + struct ub_packed_rrset_key* answer; + + verbose(VERB_ALGO, "adjusting PTR reply"); + + /* Copy the sub-query's reply to the parent. */ + if (!(super->return_msg = (struct dns_msg*)regional_alloc(super->region, + sizeof(struct dns_msg)))) + return; + super->return_msg->qinfo = super->qinfo; + super->return_msg->rep = reply_info_copy(qstate->return_msg->rep, NULL, + super->region); + + /* + * Adjust the domain name of the answer RR set so that it matches the + * initial query's domain name. + */ + answer = reply_find_answer_rrset(&qstate->qinfo, super->return_msg->rep); + log_assert(answer); + answer->rk.dname = super->qinfo.qname; + answer->rk.dname_len = super->qinfo.qname_len; +} + +/** + * This function is called when a sub-query finishes to inform the parent query. + * + * We issue two kinds of sub-queries: PTR and A. + * + * \param qstate State of the sub-query. + * \param id This module's instance ID. + * \param super State of the super-query. + */ +void +dns64_inform_super(struct module_qstate* qstate, int id, + struct module_qstate* super) +{ + log_query_info(VERB_ALGO, "dns64: inform_super, sub is", + &qstate->qinfo); + log_query_info(VERB_ALGO, "super is", &super->qinfo); + + /* + * Signal that the sub-query is finished, no matter whether we are + * successful or not. This lets the state machine terminate. + */ + super->minfo[id] = (void*)DNS64_SUBQUERY_FINISHED; + + /* If there is no successful answer, we're done. */ + if (qstate->return_rcode != LDNS_RCODE_NOERROR + || !qstate->return_msg + || !qstate->return_msg->rep + || !reply_find_answer_rrset(&qstate->qinfo, + qstate->return_msg->rep)) + return; + + /* Generate a response suitable for the original query. */ + if (qstate->qinfo.qtype == LDNS_RR_TYPE_A) { + dns64_adjust_a(id, super, qstate); + } else { + log_assert(qstate->qinfo.qtype == LDNS_RR_TYPE_PTR); + dns64_adjust_ptr(qstate, super); + } + + /* Store the generated response in cache. */ + if (!dns_cache_store(super->env, &super->qinfo, super->return_msg->rep, + 0, 0, 0, NULL)) + log_err("out of memory"); +} + +/** + * Clear module-specific data from query state. Since we do not allocate memory, + * it's just a matter of setting a pointer to NULL. + * + * \param qstate Query state. + * \param id This module's instance ID. + */ +void +dns64_clear(struct module_qstate* qstate, int id) +{ + qstate->minfo[id] = NULL; +} + +/** + * Returns the amount of global memory that this module uses, not including + * per-query data. + * + * \param env Module environment. + * \param id This module's instance ID. + */ +size_t +dns64_get_mem(struct module_env* env, int id) +{ + struct dns64_env* dns64_env = (struct dns64_env*)env->modinfo[id]; + if (!dns64_env) + return 0; + return sizeof(*dns64_env); +} + +/** + * The dns64 function block. + */ +static struct module_func_block dns64_block = { + "dns64", + &dns64_init, &dns64_deinit, &dns64_operate, &dns64_inform_super, + &dns64_clear, &dns64_get_mem +}; + +/** + * Function for returning the above function block. + */ +struct module_func_block * +dns64_get_funcblock() +{ + return &dns64_block; +} |