monero-project/monero
monero-project/monero
1
0
Fork 0
mirror of https://github.com/monero-project/monero.git synced 2024-11-18 00:37:43 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions
monero/external/unbound/dns64/dns64.c
Erik de Castro Lopo a85b5759f3 Upgrade unbound library 
These files were pulled from the 1.6.3 release tarball.

This new version builds against OpenSSL version 1.1 which will be
the default in the new Debian Stable which is due to be released
RealSoonNow (tm).
2017-06-17 23:04:00 +10:00

854 lines
26 KiB
C
Raw Blame History

/*
* 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, 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;
}
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,
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.
* - CD FLAG was set on querier
* - An AAAA query for which an error was returned.(qstate.return_rcode)
* -> treated as servfail thus synthesize (sec 5.1.3 6147), thus
* synthesize in (sec 5.1.2 of RFC6147).
* - 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->query_flags & BIT_CD)
|| (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(fd->count > RR_COUNT_MAX) {
*dd_out = NULL;
return; /* integer overflow protection in alloc */
}
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) {
*dd_out = NULL;
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");
*dd_out = NULL;
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");
*dd_out = NULL;
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(!reply_info_alloc_rrset_keys(cp, NULL, 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);
if(!dd)
return;
/* 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 (!super->no_cache_store &&
!dns_cache_store(super->env, &super->qinfo, super->return_msg->rep,
0, 0, 0, NULL, super->query_flags))
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(void)
{
return &dns64_block;
}
Reference in a new issue View git blame Copy permalink