unbound/edns-subnet/subnetmod.c
W.C.A. Wijngaards a335e601e4 ipset-pf-support, move startup and destartup to the front of the module
func block functions, modstack call deinit function names, and detect
module change when no startup functions are needed.
2024-07-03 13:53:44 +02:00

1017 lines
32 KiB
C

/*
* edns-subnet/subnetmod.c - edns subnet module. Must be called before validator
* and iterator.
*
* Copyright (c) 2013, NLnet Labs. 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 the NLNET LABS 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 COPYRIGHT
* HOLDER 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
* subnet module for unbound.
*/
#include "config.h"
#ifdef CLIENT_SUBNET /* keeps splint happy */
#include "edns-subnet/subnetmod.h"
#include "edns-subnet/edns-subnet.h"
#include "edns-subnet/addrtree.h"
#include "edns-subnet/subnet-whitelist.h"
#include "services/mesh.h"
#include "services/cache/dns.h"
#include "util/module.h"
#include "util/regional.h"
#include "util/storage/slabhash.h"
#include "util/config_file.h"
#include "util/data/msgreply.h"
#include "sldns/sbuffer.h"
#include "sldns/wire2str.h"
#include "iterator/iter_utils.h"
#ifdef USE_CACHEDB
#include "cachedb/cachedb.h"
#endif
/** externally called */
void
subnet_data_delete(void *d, void *ATTR_UNUSED(arg))
{
struct subnet_msg_cache_data *r;
r = (struct subnet_msg_cache_data*)d;
addrtree_delete(r->tree4);
addrtree_delete(r->tree6);
free(r);
}
/** externally called */
size_t
msg_cache_sizefunc(void *k, void *d)
{
struct msgreply_entry *q = (struct msgreply_entry*)k;
struct subnet_msg_cache_data *r = (struct subnet_msg_cache_data*)d;
size_t s = sizeof(struct msgreply_entry)
+ sizeof(struct subnet_msg_cache_data)
+ q->key.qname_len + lock_get_mem(&q->entry.lock);
s += addrtree_size(r->tree4);
s += addrtree_size(r->tree6);
return s;
}
/** new query for ecs module */
static int
subnet_new_qstate(struct module_qstate *qstate, int id)
{
struct subnet_qstate *sq = (struct subnet_qstate*)regional_alloc(
qstate->region, sizeof(struct subnet_qstate));
if(!sq)
return 0;
qstate->minfo[id] = sq;
memset(sq, 0, sizeof(*sq));
sq->started_no_cache_store = qstate->no_cache_store;
sq->started_no_cache_lookup = qstate->no_cache_lookup;
return 1;
}
/** Add ecs struct to edns list, after parsing it to wire format. */
void
subnet_ecs_opt_list_append(struct ecs_data* ecs, struct edns_option** list,
struct module_qstate *qstate, struct regional *region)
{
size_t sn_octs, sn_octs_remainder;
sldns_buffer* buf = qstate->env->scratch_buffer;
if(ecs->subnet_validdata) {
log_assert(ecs->subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP4 ||
ecs->subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP6);
log_assert(ecs->subnet_addr_fam != EDNSSUBNET_ADDRFAM_IP4 ||
ecs->subnet_source_mask <= INET_SIZE*8);
log_assert(ecs->subnet_addr_fam != EDNSSUBNET_ADDRFAM_IP6 ||
ecs->subnet_source_mask <= INET6_SIZE*8);
sn_octs = ecs->subnet_source_mask / 8;
sn_octs_remainder =
(size_t)((ecs->subnet_source_mask % 8)>0?1:0);
log_assert(sn_octs + sn_octs_remainder <= INET6_SIZE);
sldns_buffer_clear(buf);
sldns_buffer_write_u16(buf, ecs->subnet_addr_fam);
sldns_buffer_write_u8(buf, ecs->subnet_source_mask);
sldns_buffer_write_u8(buf, ecs->subnet_scope_mask);
sldns_buffer_write(buf, ecs->subnet_addr, sn_octs);
if(sn_octs_remainder)
sldns_buffer_write_u8(buf, ecs->subnet_addr[sn_octs] &
~(0xFF >> (ecs->subnet_source_mask % 8)));
sldns_buffer_flip(buf);
edns_opt_list_append(list,
qstate->env->cfg->client_subnet_opcode,
sn_octs + sn_octs_remainder + 4,
sldns_buffer_begin(buf), region);
}
}
int ecs_whitelist_check(struct query_info* qinfo,
uint16_t ATTR_UNUSED(flags), struct module_qstate* qstate,
struct sockaddr_storage* addr, socklen_t addrlen,
uint8_t* ATTR_UNUSED(zone), size_t ATTR_UNUSED(zonelen),
struct regional *region, int id, void* ATTR_UNUSED(cbargs))
{
struct subnet_qstate *sq;
struct subnet_env *sn_env;
if(!(sq=(struct subnet_qstate*)qstate->minfo[id]))
return 1;
sn_env = (struct subnet_env*)qstate->env->modinfo[id];
/* Cache by default, might be disabled after parsing EDNS option
* received from nameserver. */
if(!iter_stub_fwd_no_cache(qstate, &qstate->qinfo, NULL, NULL, NULL, 0)) {
qstate->no_cache_store = 0;
}
sq->subnet_sent_no_subnet = 0;
if(sq->ecs_server_out.subnet_validdata && ((sq->subnet_downstream &&
qstate->env->cfg->client_subnet_always_forward) ||
ecs_is_whitelisted(sn_env->whitelist,
addr, addrlen, qinfo->qname, qinfo->qname_len,
qinfo->qclass))) {
/* Address on whitelist or client query contains ECS option, we
* want to sent out ECS. Only add option if it is not already
* set. */
if(!edns_opt_list_find(qstate->edns_opts_back_out,
qstate->env->cfg->client_subnet_opcode)) {
/* if the client is not wanting an EDNS subnet option,
* omit it and store that we omitted it but actually
* are doing EDNS subnet to the server. */
if(sq->ecs_server_out.subnet_source_mask == 0) {
sq->subnet_sent_no_subnet = 1;
sq->subnet_sent = 0;
return 1;
}
subnet_ecs_opt_list_append(&sq->ecs_server_out,
&qstate->edns_opts_back_out, qstate, region);
}
sq->subnet_sent = 1;
}
else {
/* Outgoing ECS option is set, but we don't want to sent it to
* this address, remove option. */
if(edns_opt_list_find(qstate->edns_opts_back_out,
qstate->env->cfg->client_subnet_opcode)) {
edns_opt_list_remove(&qstate->edns_opts_back_out,
qstate->env->cfg->client_subnet_opcode);
}
sq->subnet_sent = 0;
}
return 1;
}
void
subnet_markdel(void* key)
{
struct msgreply_entry *e = (struct msgreply_entry*)key;
e->key.qtype = 0;
e->key.qclass = 0;
}
int
subnetmod_init(struct module_env *env, int id)
{
struct subnet_env *sn_env = (struct subnet_env*)calloc(1,
sizeof(struct subnet_env));
if(!sn_env) {
log_err("malloc failure");
return 0;
}
alloc_init(&sn_env->alloc, NULL, 0);
env->modinfo[id] = (void*)sn_env;
/* Warn that serve-expired and prefetch do not work with the subnet
* module cache. */
if(env->cfg->serve_expired)
log_warn(
"subnetcache: serve-expired is set but not working "
"for data originating from the subnet module cache.");
if(env->cfg->prefetch)
log_warn(
"subnetcache: prefetch is set but not working "
"for data originating from the subnet module cache.");
/* Copy msg_cache settings */
sn_env->subnet_msg_cache = slabhash_create(env->cfg->msg_cache_slabs,
HASH_DEFAULT_STARTARRAY, env->cfg->msg_cache_size,
msg_cache_sizefunc, query_info_compare, query_entry_delete,
subnet_data_delete, NULL);
slabhash_setmarkdel(sn_env->subnet_msg_cache, &subnet_markdel);
if(!sn_env->subnet_msg_cache) {
log_err("subnetcache: could not create cache");
free(sn_env);
env->modinfo[id] = NULL;
return 0;
}
/* whitelist for edns subnet capable servers */
sn_env->whitelist = ecs_whitelist_create();
if(!sn_env->whitelist ||
!ecs_whitelist_apply_cfg(sn_env->whitelist, env->cfg)) {
log_err("subnetcache: could not create ECS whitelist");
slabhash_delete(sn_env->subnet_msg_cache);
free(sn_env);
env->modinfo[id] = NULL;
return 0;
}
verbose(VERB_QUERY, "subnetcache: option registered (%d)",
env->cfg->client_subnet_opcode);
/* Create new mesh state for all queries. */
env->unique_mesh = 1;
if(!edns_register_option(env->cfg->client_subnet_opcode,
env->cfg->client_subnet_always_forward /* bypass cache */,
1 /* no aggregation */, env)) {
log_err("subnetcache: could not register opcode");
ecs_whitelist_delete(sn_env->whitelist);
slabhash_delete(sn_env->subnet_msg_cache);
free(sn_env);
env->modinfo[id] = NULL;
return 0;
}
inplace_cb_register((void*)ecs_whitelist_check, inplace_cb_query, NULL,
env, id);
inplace_cb_register((void*)ecs_edns_back_parsed,
inplace_cb_edns_back_parsed, NULL, env, id);
inplace_cb_register((void*)ecs_query_response,
inplace_cb_query_response, NULL, env, id);
lock_rw_init(&sn_env->biglock);
return 1;
}
void
subnetmod_deinit(struct module_env *env, int id)
{
struct subnet_env *sn_env;
if(!env || !env->modinfo[id])
return;
sn_env = (struct subnet_env*)env->modinfo[id];
lock_rw_destroy(&sn_env->biglock);
inplace_cb_delete(env, inplace_cb_edns_back_parsed, id);
inplace_cb_delete(env, inplace_cb_query, id);
inplace_cb_delete(env, inplace_cb_query_response, id);
ecs_whitelist_delete(sn_env->whitelist);
slabhash_delete(sn_env->subnet_msg_cache);
alloc_clear(&sn_env->alloc);
free(sn_env);
env->modinfo[id] = NULL;
}
/** Tells client that upstream has no/improper support */
static void
cp_edns_bad_response(struct ecs_data *target, struct ecs_data *source)
{
target->subnet_scope_mask = 0;
target->subnet_source_mask = source->subnet_source_mask;
target->subnet_addr_fam = source->subnet_addr_fam;
memcpy(target->subnet_addr, source->subnet_addr, INET6_SIZE);
target->subnet_validdata = 1;
}
static void
delfunc(void *envptr, void *elemptr) {
struct reply_info *elem = (struct reply_info *)elemptr;
struct subnet_env *env = (struct subnet_env *)envptr;
reply_info_parsedelete(elem, &env->alloc);
}
static size_t
sizefunc(void *elemptr) {
struct reply_info *elem = (struct reply_info *)elemptr;
size_t s = sizeof (struct reply_info) - sizeof (struct rrset_ref)
+ elem->rrset_count * sizeof (struct rrset_ref)
+ elem->rrset_count * sizeof (struct ub_packed_rrset_key *);
size_t i;
for (i = 0; i < elem->rrset_count; i++) {
struct ub_packed_rrset_key *key = elem->rrsets[i];
struct packed_rrset_data *data = key->entry.data;
s += ub_rrset_sizefunc(key, data);
}
if(elem->reason_bogus_str)
s += strlen(elem->reason_bogus_str)+1;
return s;
}
/**
* Select tree from cache entry based on edns data.
* If for address family not present it will create a new one.
* NULL on failure to create. */
static struct addrtree*
get_tree(struct subnet_msg_cache_data *data, struct ecs_data *edns,
struct subnet_env *env, struct config_file* cfg)
{
struct addrtree *tree;
if (edns->subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP4) {
if (!data->tree4)
data->tree4 = addrtree_create(
cfg->max_client_subnet_ipv4, &delfunc,
&sizefunc, env, cfg->max_ecs_tree_size_ipv4);
tree = data->tree4;
} else {
if (!data->tree6)
data->tree6 = addrtree_create(
cfg->max_client_subnet_ipv6, &delfunc,
&sizefunc, env, cfg->max_ecs_tree_size_ipv6);
tree = data->tree6;
}
return tree;
}
static void
update_cache(struct module_qstate *qstate, int id)
{
struct msgreply_entry *mrep_entry;
struct addrtree *tree;
struct reply_info *rep;
struct query_info qinf;
struct subnet_env *sne = qstate->env->modinfo[id];
struct subnet_qstate *sq = (struct subnet_qstate*)qstate->minfo[id];
struct slabhash *subnet_msg_cache = sne->subnet_msg_cache;
struct ecs_data *edns = &sq->ecs_client_in;
size_t i;
int only_match_scope_zero, diff_size;
/* We already calculated hash upon lookup (lookup_and_reply) if we were
* allowed to look in the ECS cache */
hashvalue_type h = qstate->minfo[id] &&
((struct subnet_qstate*)qstate->minfo[id])->qinfo_hash_calculated?
((struct subnet_qstate*)qstate->minfo[id])->qinfo_hash :
query_info_hash(&qstate->qinfo, qstate->query_flags);
/* Step 1, general qinfo lookup */
struct lruhash_entry* lru_entry = slabhash_lookup(subnet_msg_cache, h,
&qstate->qinfo, 1);
int need_to_insert = (lru_entry == NULL);
if (!lru_entry) {
void* data = calloc(1,
sizeof(struct subnet_msg_cache_data));
if(!data) {
log_err("malloc failed");
return;
}
qinf = qstate->qinfo;
qinf.qname = memdup(qstate->qinfo.qname,
qstate->qinfo.qname_len);
if(!qinf.qname) {
free(data);
log_err("memdup failed");
return;
}
mrep_entry = query_info_entrysetup(&qinf, data, h);
free(qinf.qname); /* if qname 'consumed', it is set to NULL */
if (!mrep_entry) {
free(data);
log_err("query_info_entrysetup failed");
return;
}
lru_entry = &mrep_entry->entry;
lock_rw_wrlock(&lru_entry->lock);
}
/* lru_entry->lock is locked regardless of how we got here,
* either from the slabhash_lookup, or above in the new allocated */
/* Step 2, find the correct tree */
if (!(tree = get_tree(lru_entry->data, edns, sne, qstate->env->cfg))) {
lock_rw_unlock(&lru_entry->lock);
log_err("subnetcache: cache insertion failed");
return;
}
lock_quick_lock(&sne->alloc.lock);
rep = reply_info_copy(qstate->return_msg->rep, &sne->alloc, NULL);
lock_quick_unlock(&sne->alloc.lock);
if (!rep) {
lock_rw_unlock(&lru_entry->lock);
log_err("subnetcache: cache insertion failed");
return;
}
/* store RRsets */
for(i=0; i<rep->rrset_count; i++) {
rep->ref[i].key = rep->rrsets[i];
rep->ref[i].id = rep->rrsets[i]->id;
}
reply_info_set_ttls(rep, *qstate->env->now);
reply_info_sortref(rep);
rep->flags |= (BIT_RA | BIT_QR); /* fix flags to be sensible for */
rep->flags &= ~(BIT_AA | BIT_CD);/* a reply based on the cache */
if(edns->subnet_source_mask == 0 && edns->subnet_scope_mask == 0)
only_match_scope_zero = 1;
else only_match_scope_zero = 0;
diff_size = (int)tree->size_bytes;
addrtree_insert(tree, (addrkey_t*)edns->subnet_addr,
edns->subnet_source_mask, sq->max_scope, rep,
rep->ttl, *qstate->env->now, only_match_scope_zero);
diff_size = (int)tree->size_bytes - diff_size;
lock_rw_unlock(&lru_entry->lock);
if (need_to_insert) {
slabhash_insert(subnet_msg_cache, h, lru_entry, lru_entry->data,
NULL);
} else {
slabhash_update_space_used(subnet_msg_cache, h, NULL,
diff_size);
}
}
/** Lookup in cache and reply true iff reply is sent. */
static int
lookup_and_reply(struct module_qstate *qstate, int id, struct subnet_qstate *sq, int prefetch)
{
struct lruhash_entry *e;
struct module_env *env = qstate->env;
struct subnet_env *sne = (struct subnet_env*)env->modinfo[id];
hashvalue_type h = query_info_hash(&qstate->qinfo, qstate->query_flags);
struct subnet_msg_cache_data *data;
struct ecs_data *ecs = &sq->ecs_client_in;
struct addrtree *tree;
struct addrnode *node;
uint8_t scope;
memset(&sq->ecs_client_out, 0, sizeof(sq->ecs_client_out));
if (sq) {
sq->qinfo_hash = h; /* Might be useful on cache miss */
sq->qinfo_hash_calculated = 1;
}
e = slabhash_lookup(sne->subnet_msg_cache, h, &qstate->qinfo, 1);
if (!e) return 0; /* qinfo not in cache */
data = e->data;
tree = (ecs->subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP4)?
data->tree4 : data->tree6;
if (!tree) { /* qinfo in cache but not for this family */
lock_rw_unlock(&e->lock);
return 0;
}
node = addrtree_find(tree, (addrkey_t*)ecs->subnet_addr,
ecs->subnet_source_mask, *env->now);
if (!node) { /* plain old cache miss */
lock_rw_unlock(&e->lock);
return 0;
}
qstate->return_msg = tomsg(NULL, &qstate->qinfo,
(struct reply_info *)node->elem, qstate->region, *env->now, 0,
env->scratch);
scope = (uint8_t)node->scope;
lock_rw_unlock(&e->lock);
if (!qstate->return_msg) { /* Failed allocation or expired TTL */
return 0;
}
if (sq->subnet_downstream) { /* relay to interested client */
sq->ecs_client_out.subnet_scope_mask = scope;
sq->ecs_client_out.subnet_addr_fam = ecs->subnet_addr_fam;
sq->ecs_client_out.subnet_source_mask = ecs->subnet_source_mask;
memcpy(&sq->ecs_client_out.subnet_addr, &ecs->subnet_addr,
INET6_SIZE);
sq->ecs_client_out.subnet_validdata = 1;
}
if (prefetch && *qstate->env->now >= ((struct reply_info *)node->elem)->prefetch_ttl) {
qstate->need_refetch = 1;
}
return 1;
}
/**
* Test first bits of addresses for equality. Caller is responsible
* for making sure that both a and b are at least net/8 octets long.
* @param a: first address.
* @param a: seconds address.
* @param net: Number of bits to test.
* @return: 1 if equal, 0 otherwise.
*/
static int
common_prefix(uint8_t *a, uint8_t *b, uint8_t net)
{
size_t n = (size_t)net / 8;
return !memcmp(a, b, n) && ((net % 8) == 0 || a[n] == b[n]);
}
static enum module_ext_state
eval_response(struct module_qstate *qstate, int id, struct subnet_qstate *sq)
{
struct subnet_env *sne = qstate->env->modinfo[id];
struct ecs_data *c_in = &sq->ecs_client_in; /* rcvd from client */
struct ecs_data *c_out = &sq->ecs_client_out;/* will send to client */
struct ecs_data *s_in = &sq->ecs_server_in; /* rcvd from auth */
struct ecs_data *s_out = &sq->ecs_server_out;/* sent to auth */
memset(c_out, 0, sizeof(*c_out));
if (!qstate->return_msg) {
/* already an answer and its not a message, but retain
* the actual rcode, instead of module_error, so send
* module_finished */
return module_finished;
}
/* We have not asked for subnet data */
if (!sq->subnet_sent && !sq->subnet_sent_no_subnet) {
if (s_in->subnet_validdata)
verbose(VERB_QUERY, "subnetcache: received spurious data");
if (sq->subnet_downstream) /* Copy back to client */
cp_edns_bad_response(c_out, c_in);
return module_finished;
}
/* subnet sent but nothing came back */
if (!s_in->subnet_validdata && !sq->subnet_sent_no_subnet) {
/* The authority indicated no support for edns subnet. As a
* consequence the answer ended up in the regular cache. It
* is still useful to put it in the edns subnet cache for
* when a client explicitly asks for subnet specific answer. */
verbose(VERB_QUERY, "subnetcache: Authority indicates no support");
if(!sq->started_no_cache_store) {
lock_rw_wrlock(&sne->biglock);
update_cache(qstate, id);
lock_rw_unlock(&sne->biglock);
}
if (sq->subnet_downstream)
cp_edns_bad_response(c_out, c_in);
return module_finished;
}
/* Purposefully there was no sent subnet, and there is consequently
* no subnet in the answer. If there was, use the subnet in the answer
* anyway. But if there is not, treat it as a prefix 0 answer. */
if(sq->subnet_sent_no_subnet && !s_in->subnet_validdata) {
/* Fill in 0.0.0.0/0 scope 0, or ::0/0 scope 0, for caching. */
s_in->subnet_addr_fam = s_out->subnet_addr_fam;
s_in->subnet_source_mask = 0;
s_in->subnet_scope_mask = 0;
memset(s_in->subnet_addr, 0, INET6_SIZE);
s_in->subnet_validdata = 1;
}
/* Being here means we have asked for and got a subnet specific
* answer. Also, the answer from the authority is not yet cached
* anywhere. */
/* can we accept response? */
if(s_out->subnet_addr_fam != s_in->subnet_addr_fam ||
s_out->subnet_source_mask != s_in->subnet_source_mask ||
!common_prefix(s_out->subnet_addr, s_in->subnet_addr,
s_out->subnet_source_mask))
{
/* we can not accept, restart query without option */
verbose(VERB_QUERY, "subnetcache: forged data");
s_out->subnet_validdata = 0;
(void)edns_opt_list_remove(&qstate->edns_opts_back_out,
qstate->env->cfg->client_subnet_opcode);
sq->subnet_sent = 0;
sq->subnet_sent_no_subnet = 0;
return module_restart_next;
}
lock_rw_wrlock(&sne->biglock);
if(!sq->started_no_cache_store) {
update_cache(qstate, id);
}
sne->num_msg_nocache++;
lock_rw_unlock(&sne->biglock);
/* If there is an expired answer in the global cache, remove that,
* because expired answers would otherwise resurface once the ecs data
* expires, giving once in a while global data responses for ecs
* domains, with serve expired enabled. */
if(qstate->env->cfg->serve_expired) {
msg_cache_remove(qstate->env, qstate->qinfo.qname,
qstate->qinfo.qname_len, qstate->qinfo.qtype,
qstate->qinfo.qclass, 0);
#ifdef USE_CACHEDB
if(qstate->env->cachedb_enabled)
cachedb_msg_remove(qstate);
#endif
}
if (sq->subnet_downstream) {
/* Client wants to see the answer, echo option back
* and adjust the scope. */
c_out->subnet_addr_fam = c_in->subnet_addr_fam;
c_out->subnet_source_mask = c_in->subnet_source_mask;
memcpy(&c_out->subnet_addr, &c_in->subnet_addr, INET6_SIZE);
c_out->subnet_scope_mask = sq->max_scope;
/* Limit scope returned to client to scope used for caching. */
if(c_out->subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP4) {
if(c_out->subnet_scope_mask >
qstate->env->cfg->max_client_subnet_ipv4) {
c_out->subnet_scope_mask =
qstate->env->cfg->max_client_subnet_ipv4;
}
}
else if(c_out->subnet_scope_mask >
qstate->env->cfg->max_client_subnet_ipv6) {
c_out->subnet_scope_mask =
qstate->env->cfg->max_client_subnet_ipv6;
}
c_out->subnet_validdata = 1;
}
return module_finished;
}
/** Parse EDNS opt data containing ECS */
static int
parse_subnet_option(struct edns_option* ecs_option, struct ecs_data* ecs)
{
memset(ecs, 0, sizeof(*ecs));
if (ecs_option->opt_len < 4)
return 0;
ecs->subnet_addr_fam = sldns_read_uint16(ecs_option->opt_data);
ecs->subnet_source_mask = ecs_option->opt_data[2];
ecs->subnet_scope_mask = ecs_option->opt_data[3];
/* remaining bytes indicate address */
/* validate input*/
/* option length matches calculated length? */
if (ecs_option->opt_len != (size_t)((ecs->subnet_source_mask+7)/8 + 4))
return 0;
if (ecs_option->opt_len - 4 > INET6_SIZE || ecs_option->opt_len == 0)
return 0;
if (ecs->subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP4) {
if (ecs->subnet_source_mask > 32 || ecs->subnet_scope_mask > 32)
return 0;
} else if (ecs->subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP6) {
if (ecs->subnet_source_mask > 128 ||
ecs->subnet_scope_mask > 128)
return 0;
} else
return 0;
/* valid ECS data, write to ecs_data */
if (copy_clear(ecs->subnet_addr, INET6_SIZE, ecs_option->opt_data + 4,
ecs_option->opt_len - 4, ecs->subnet_source_mask))
return 0;
ecs->subnet_validdata = 1;
return 1;
}
void
subnet_option_from_ss(struct sockaddr_storage *ss, struct ecs_data* ecs,
struct config_file* cfg)
{
void* sinaddr;
/* Construct subnet option from original query */
if(((struct sockaddr_in*)ss)->sin_family == AF_INET) {
ecs->subnet_source_mask = cfg->max_client_subnet_ipv4;
ecs->subnet_addr_fam = EDNSSUBNET_ADDRFAM_IP4;
sinaddr = &((struct sockaddr_in*)ss)->sin_addr;
if (!copy_clear( ecs->subnet_addr, INET6_SIZE,
(uint8_t *)sinaddr, INET_SIZE,
ecs->subnet_source_mask)) {
ecs->subnet_validdata = 1;
}
}
#ifdef INET6
else {
ecs->subnet_source_mask = cfg->max_client_subnet_ipv6;
ecs->subnet_addr_fam = EDNSSUBNET_ADDRFAM_IP6;
sinaddr = &((struct sockaddr_in6*)ss)->sin6_addr;
if (!copy_clear( ecs->subnet_addr, INET6_SIZE,
(uint8_t *)sinaddr, INET6_SIZE,
ecs->subnet_source_mask)) {
ecs->subnet_validdata = 1;
}
}
#else
/* We don't know how to handle ip6, just pass */
#endif /* INET6 */
}
int
ecs_query_response(struct module_qstate* qstate, struct dns_msg* response,
int id, void* ATTR_UNUSED(cbargs))
{
struct subnet_qstate *sq;
if(!response || !(sq=(struct subnet_qstate*)qstate->minfo[id]))
return 1;
if(sq->subnet_sent &&
FLAGS_GET_RCODE(response->rep->flags) == LDNS_RCODE_REFUSED) {
/* REFUSED response to ECS query, remove ECS option. */
edns_opt_list_remove(&qstate->edns_opts_back_out,
qstate->env->cfg->client_subnet_opcode);
sq->subnet_sent = 0;
sq->subnet_sent_no_subnet = 0;
memset(&sq->ecs_server_out, 0, sizeof(sq->ecs_server_out));
} else if (!sq->track_max_scope &&
FLAGS_GET_RCODE(response->rep->flags) == LDNS_RCODE_NOERROR &&
response->rep->an_numrrsets > 0
) {
struct ub_packed_rrset_key* s = response->rep->rrsets[0];
if(ntohs(s->rk.type) == LDNS_RR_TYPE_CNAME &&
query_dname_compare(qstate->qinfo.qname,
s->rk.dname) == 0) {
/* CNAME response for QNAME. From now on keep track of
* longest received ECS prefix for all queries on this
* qstate. */
sq->track_max_scope = 1;
}
}
return 1;
}
/** verbose print edns subnet option in pretty print */
static void
subnet_log_print(const char* s, struct edns_option* ecs_opt)
{
if(verbosity >= VERB_ALGO) {
char buf[256];
char* str = buf;
size_t str_len = sizeof(buf);
if(!ecs_opt) {
verbose(VERB_ALGO, "%s (null)", s);
return;
}
(void)sldns_wire2str_edns_subnet_print(&str, &str_len,
ecs_opt->opt_data, ecs_opt->opt_len);
verbose(VERB_ALGO, "%s %s", s, buf);
}
}
int
ecs_edns_back_parsed(struct module_qstate* qstate, int id,
void* ATTR_UNUSED(cbargs))
{
struct subnet_qstate *sq;
struct edns_option* ecs_opt;
if(!(sq=(struct subnet_qstate*)qstate->minfo[id]))
return 1;
if((ecs_opt = edns_opt_list_find(
qstate->edns_opts_back_in,
qstate->env->cfg->client_subnet_opcode)) &&
parse_subnet_option(ecs_opt, &sq->ecs_server_in) &&
sq->subnet_sent && sq->ecs_server_in.subnet_validdata) {
subnet_log_print("answer has edns subnet", ecs_opt);
/* Only skip global cache store if we sent an ECS option
* and received one back. Answers from non-whitelisted
* servers will end up in global cache. Answers for
* queries with 0 source will not (unless nameserver
* does not support ECS). */
qstate->no_cache_store = 1;
if(!sq->track_max_scope || (sq->track_max_scope &&
sq->ecs_server_in.subnet_scope_mask >
sq->max_scope))
sq->max_scope = sq->ecs_server_in.subnet_scope_mask;
} else if(sq->subnet_sent_no_subnet) {
/* The answer can be stored as scope 0, not in global cache. */
qstate->no_cache_store = 1;
}
return 1;
}
void
subnetmod_operate(struct module_qstate *qstate, enum module_ev event,
int id, struct outbound_entry* outbound)
{
struct subnet_env *sne = qstate->env->modinfo[id];
struct subnet_qstate *sq = (struct subnet_qstate*)qstate->minfo[id];
verbose(VERB_QUERY, "subnetcache[module %d] operate: extstate:%s "
"event:%s", id, strextstate(qstate->ext_state[id]),
strmodulevent(event));
log_query_info(VERB_QUERY, "subnetcache operate: query", &qstate->qinfo);
if((event == module_event_new || event == module_event_pass) &&
sq == NULL) {
struct edns_option* ecs_opt;
if(!subnet_new_qstate(qstate, id)) {
qstate->return_msg = NULL;
qstate->ext_state[id] = module_finished;
return;
}
sq = (struct subnet_qstate*)qstate->minfo[id];
if((ecs_opt = edns_opt_list_find(
qstate->edns_opts_front_in,
qstate->env->cfg->client_subnet_opcode))) {
if(!parse_subnet_option(ecs_opt, &sq->ecs_client_in)) {
/* Wrongly formatted ECS option. RFC mandates to
* return FORMERROR. */
qstate->return_rcode = LDNS_RCODE_FORMERR;
qstate->ext_state[id] = module_finished;
return;
}
subnet_log_print("query has edns subnet", ecs_opt);
sq->subnet_downstream = 1;
}
else if(qstate->mesh_info->reply_list) {
subnet_option_from_ss(
&qstate->mesh_info->reply_list->query_reply.client_addr,
&sq->ecs_client_in, qstate->env->cfg);
}
else if(qstate->client_addr.ss_family != AF_UNSPEC) {
subnet_option_from_ss(
&qstate->client_addr,
&sq->ecs_client_in, qstate->env->cfg);
}
if(sq->ecs_client_in.subnet_validdata == 0) {
/* No clients are interested in result or we could not
* parse it, we don't do client subnet */
sq->ecs_server_out.subnet_validdata = 0;
verbose(VERB_ALGO, "subnetcache: pass to next module");
qstate->ext_state[id] = module_wait_module;
return;
}
/* Limit to minimum allowed source mask */
if(sq->ecs_client_in.subnet_source_mask != 0 && (
(sq->ecs_client_in.subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP4 &&
sq->ecs_client_in.subnet_source_mask < qstate->env->cfg->min_client_subnet_ipv4) ||
(sq->ecs_client_in.subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP6 &&
sq->ecs_client_in.subnet_source_mask < qstate->env->cfg->min_client_subnet_ipv6))) {
qstate->return_rcode = LDNS_RCODE_REFUSED;
qstate->ext_state[id] = module_finished;
return;
}
if(!sq->started_no_cache_lookup && !qstate->blacklist) {
lock_rw_wrlock(&sne->biglock);
if(qstate->mesh_info->reply_list &&
lookup_and_reply(qstate, id, sq,
qstate->env->cfg->prefetch)) {
sne->num_msg_cache++;
lock_rw_unlock(&sne->biglock);
verbose(VERB_QUERY, "subnetcache: answered from cache");
qstate->ext_state[id] = module_finished;
subnet_ecs_opt_list_append(&sq->ecs_client_out,
&qstate->edns_opts_front_out, qstate,
qstate->region);
if(verbosity >= VERB_ALGO) {
subnet_log_print("reply has edns subnet",
edns_opt_list_find(
qstate->edns_opts_front_out,
qstate->env->cfg->
client_subnet_opcode));
}
return;
}
lock_rw_unlock(&sne->biglock);
}
sq->ecs_server_out.subnet_addr_fam =
sq->ecs_client_in.subnet_addr_fam;
sq->ecs_server_out.subnet_source_mask =
sq->ecs_client_in.subnet_source_mask;
/* Limit source prefix to configured maximum */
if(sq->ecs_server_out.subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP4
&& sq->ecs_server_out.subnet_source_mask >
qstate->env->cfg->max_client_subnet_ipv4)
sq->ecs_server_out.subnet_source_mask =
qstate->env->cfg->max_client_subnet_ipv4;
else if(sq->ecs_server_out.subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP6
&& sq->ecs_server_out.subnet_source_mask >
qstate->env->cfg->max_client_subnet_ipv6)
sq->ecs_server_out.subnet_source_mask =
qstate->env->cfg->max_client_subnet_ipv6;
/* Safe to copy completely, even if the source is limited by the
* configuration. subnet_ecs_opt_list_append() will limit the address.
* */
memcpy(&sq->ecs_server_out.subnet_addr,
sq->ecs_client_in.subnet_addr, INET6_SIZE);
sq->ecs_server_out.subnet_scope_mask = 0;
sq->ecs_server_out.subnet_validdata = 1;
if(sq->ecs_server_out.subnet_source_mask != 0 &&
qstate->env->cfg->client_subnet_always_forward &&
sq->subnet_downstream)
/* ECS specific data required, do not look at the global
* cache in other modules. */
qstate->no_cache_lookup = 1;
/* pass request to next module */
verbose(VERB_ALGO,
"subnetcache: not found in cache. pass to next module");
qstate->ext_state[id] = module_wait_module;
return;
}
/* Query handed back by next module, we have a 'final' answer */
if(sq && event == module_event_moddone) {
qstate->ext_state[id] = eval_response(qstate, id, sq);
if(qstate->ext_state[id] == module_finished &&
qstate->return_msg) {
subnet_ecs_opt_list_append(&sq->ecs_client_out,
&qstate->edns_opts_front_out, qstate,
qstate->region);
if(verbosity >= VERB_ALGO) {
subnet_log_print("reply has edns subnet",
edns_opt_list_find(
qstate->edns_opts_front_out,
qstate->env->cfg->
client_subnet_opcode));
}
}
qstate->no_cache_store = sq->started_no_cache_store;
qstate->no_cache_lookup = sq->started_no_cache_lookup;
return;
}
if(sq && outbound) {
return;
}
/* We are being revisited */
if(event == module_event_pass || event == module_event_new) {
/* Just pass it on, we already did the work */
verbose(VERB_ALGO, "subnetcache: pass to next module");
qstate->ext_state[id] = module_wait_module;
return;
}
if(!sq && (event == module_event_moddone)) {
/* during priming, module done but we never started */
qstate->ext_state[id] = module_finished;
return;
}
log_err("subnetcache: bad event %s", strmodulevent(event));
qstate->ext_state[id] = module_error;
return;
}
void
subnetmod_clear(struct module_qstate *ATTR_UNUSED(qstate),
int ATTR_UNUSED(id))
{
/* qstate has no data outside region */
}
void
subnetmod_inform_super(struct module_qstate *ATTR_UNUSED(qstate),
int ATTR_UNUSED(id), struct module_qstate *ATTR_UNUSED(super))
{
/* Not used */
}
size_t
subnetmod_get_mem(struct module_env *env, int id)
{
struct subnet_env *sn_env = env->modinfo[id];
if (!sn_env) return 0;
return sizeof(*sn_env) +
slabhash_get_mem(sn_env->subnet_msg_cache) +
ecs_whitelist_get_mem(sn_env->whitelist);
}
/**
* The module function block
*/
static struct module_func_block subnetmod_block = {
"subnetcache",
NULL, NULL, &subnetmod_init, &subnetmod_deinit, &subnetmod_operate,
&subnetmod_inform_super, &subnetmod_clear, &subnetmod_get_mem
};
struct module_func_block*
subnetmod_get_funcblock(void)
{
return &subnetmod_block;
}
/** Wrappers for static functions to unit test */
size_t
unittest_wrapper_subnetmod_sizefunc(void *elemptr)
{
return sizefunc(elemptr);
}
#endif /* CLIENT_SUBNET */