contrib/unbound/edns-subnet/subnetmod.c

   1 /*
   2  * edns-subnet/subnetmod.c - edns subnet module. Must be called before validator
   3  * and iterator.
   4  *
   5  * Copyright (c) 2013, NLnet Labs. All rights reserved.
   6  *
   7  * This software is open source.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  *
  13  * Redistributions of source code must retain the above copyright notice,
  14  * this list of conditions and the following disclaimer.
  15  *
  16  * Redistributions in binary form must reproduce the above copyright notice,
  17  * this list of conditions and the following disclaimer in the documentation
  18  * and/or other materials provided with the distribution.
  19  *
  20  * Neither the name of the NLNET LABS nor the names of its contributors may
  21  * be used to endorse or promote products derived from this software without
  22  * specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  25  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  26  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  27  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  28  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  29  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  30  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  31  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  32  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  33  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  34  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  */
  36  /**
  37  * \file
  38  * subnet module for unbound.
  39  */
  40
  41 #include "config.h"
  42
  43 #ifdef CLIENT_SUBNET /* keeps splint happy */
  44
  45 #include "edns-subnet/subnetmod.h"
  46 #include "edns-subnet/edns-subnet.h"
  47 #include "edns-subnet/addrtree.h"
  48 #include "edns-subnet/subnet-whitelist.h"
  49
  50 #include "services/mesh.h"
  51 #include "services/cache/dns.h"
  52 #include "util/module.h"
  53 #include "util/regional.h"
  54 #include "util/storage/slabhash.h"
  55 #include "util/config_file.h"
  56 #include "util/data/msgreply.h"
  57 #include "sldns/sbuffer.h"
  58
  59 #define ECS_MAX_TREESIZE 100
  60
  61 /** externally called */
  62 void
  63 subnet_data_delete(void *d, void *ATTR_UNUSED(arg))
  64 {
  65         struct subnet_msg_cache_data *r;
  66         r = (struct subnet_msg_cache_data*)d;
  67         addrtree_delete(r->tree4);
  68         addrtree_delete(r->tree6);
  69         free(r);
  70 }
  71
  72 /** externally called */
  73 size_t
  74 msg_cache_sizefunc(void *k, void *d)
  75 {
  76         struct msgreply_entry *q = (struct msgreply_entry*)k;
  77         struct subnet_msg_cache_data *r = (struct subnet_msg_cache_data*)d;
  78         size_t s = sizeof(struct msgreply_entry)
  79                 + sizeof(struct subnet_msg_cache_data)
  80                 + q->key.qname_len + lock_get_mem(&q->entry.lock);
  81         s += addrtree_size(r->tree4);
  82         s += addrtree_size(r->tree6);
  83         return s;
  84 }
  85
  86 /** new query for ecs module */
  87 static int
  88 subnet_new_qstate(struct module_qstate *qstate, int id)
  89 {
  90         struct subnet_qstate *sq = (struct subnet_qstate*)regional_alloc(
  91                 qstate->region, sizeof(struct subnet_qstate));
  92         if(!sq)
  93                 return 0;
  94         qstate->minfo[id] = sq;
  95         memset(sq, 0, sizeof(*sq));
  96         return 1;
  97 }
  98
  99 /** Add ecs struct to edns list, after parsing it to wire format. */
 100 static void
 101 ecs_opt_list_append(struct ecs_data* ecs, struct edns_option** list,
 102         struct module_qstate *qstate)
 103 {
 104         size_t sn_octs, sn_octs_remainder;
 105         sldns_buffer* buf = qstate->env->scratch_buffer;
 106
 107         if(ecs->subnet_validdata) {
 108                 log_assert(ecs->subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP4 ||
 109                         ecs->subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP6);
 110                 log_assert(ecs->subnet_addr_fam != EDNSSUBNET_ADDRFAM_IP4 ||
 111                         ecs->subnet_source_mask <=  INET_SIZE*8);
 112                 log_assert(ecs->subnet_addr_fam != EDNSSUBNET_ADDRFAM_IP6 ||
 113                         ecs->subnet_source_mask <= INET6_SIZE*8);
 114
 115                 sn_octs = ecs->subnet_source_mask / 8;
 116                 sn_octs_remainder =
 117                         (size_t)((ecs->subnet_source_mask % 8)>0?1:0);
 118
 119                 log_assert(sn_octs + sn_octs_remainder <= INET6_SIZE);
 120
 121                 sldns_buffer_clear(buf);
 122                 sldns_buffer_write_u16(buf, ecs->subnet_addr_fam);
 123                 sldns_buffer_write_u8(buf, ecs->subnet_source_mask);
 124                 sldns_buffer_write_u8(buf, ecs->subnet_scope_mask);
 125                 sldns_buffer_write(buf, ecs->subnet_addr, sn_octs);
 126                 if(sn_octs_remainder)
 127                         sldns_buffer_write_u8(buf, ecs->subnet_addr[sn_octs] &
 128                                 ~(0xFF >> (ecs->subnet_source_mask % 8)));
 129                 sldns_buffer_flip(buf);
 130
 131                 edns_opt_list_append(list,
 132                                 qstate->env->cfg->client_subnet_opcode,
 133                                 sn_octs + sn_octs_remainder + 4,
 134                                 sldns_buffer_begin(buf), qstate->region);
 135         }
 136 }
 137
 138 int ecs_whitelist_check(struct query_info* qinfo,
 139         uint16_t ATTR_UNUSED(flags), struct module_qstate* qstate,
 140         struct sockaddr_storage* addr, socklen_t addrlen,
 141         uint8_t* ATTR_UNUSED(zone), size_t ATTR_UNUSED(zonelen),
 142         struct regional* ATTR_UNUSED(region), int id, void* ATTR_UNUSED(cbargs))
 143 {
 144         struct subnet_qstate *sq;
 145         struct subnet_env *sn_env;
 146
 147         if(!(sq=(struct subnet_qstate*)qstate->minfo[id]))
 148                 return 1;
 149         sn_env = (struct subnet_env*)qstate->env->modinfo[id];
 150
 151         /* Cache by default, might be disabled after parsing EDNS option
 152          * received from nameserver. */
 153         qstate->no_cache_store = 0;
 154
 155         if(sq->ecs_server_out.subnet_validdata && ((sq->subnet_downstream &&
 156                 qstate->env->cfg->client_subnet_always_forward) ||
 157                 ecs_is_whitelisted(sn_env->whitelist,
 158                 addr, addrlen, qinfo->qname, qinfo->qname_len,
 159                 qinfo->qclass))) {
 160                 /* Address on whitelist or client query contains ECS option, we
 161                  * want to sent out ECS. Only add option if it is not already
 162                  * set. */
 163                 if(!(sq->subnet_sent)) {
 164                         ecs_opt_list_append(&sq->ecs_server_out,
 165                                 &qstate->edns_opts_back_out, qstate);
 166                         sq->subnet_sent = 1;
 167                 }
 168         }
 169         else if(sq->subnet_sent) {
 170                 /* Outgoing ECS option is set, but we don't want to sent it to
 171                  * this address, remove option. */
 172                 edns_opt_list_remove(&qstate->edns_opts_back_out,
 173                         qstate->env->cfg->client_subnet_opcode);
 174                 sq->subnet_sent = 0;
 175         }
 176         return 1;
 177 }
 178
 179
 180 int
 181 subnetmod_init(struct module_env *env, int id)
 182 {
 183         struct subnet_env *sn_env = (struct subnet_env*)calloc(1,
 184                 sizeof(struct subnet_env));
 185         if(!sn_env) {
 186                 log_err("malloc failure");
 187                 return 0;
 188         }
 189         alloc_init(&sn_env->alloc, NULL, 0);
 190         env->modinfo[id] = (void*)sn_env;
 191         /* Copy msg_cache settings */
 192         sn_env->subnet_msg_cache = slabhash_create(env->cfg->msg_cache_slabs,
 193                 HASH_DEFAULT_STARTARRAY, env->cfg->msg_cache_size,
 194                 msg_cache_sizefunc, query_info_compare, query_entry_delete,
 195                 subnet_data_delete, NULL);
 196         if(!sn_env->subnet_msg_cache) {
 197                 log_err("subnet: could not create cache");
 198                 free(sn_env);
 199                 env->modinfo[id] = NULL;
 200                 return 0;
 201         }
 202         /* whitelist for edns subnet capable servers */
 203         sn_env->whitelist = ecs_whitelist_create();
 204         if(!sn_env->whitelist ||
 205                 !ecs_whitelist_apply_cfg(sn_env->whitelist, env->cfg)) {
 206                 log_err("subnet: could not create ECS whitelist");
 207                 slabhash_delete(sn_env->subnet_msg_cache);
 208                 free(sn_env);
 209                 env->modinfo[id] = NULL;
 210                 return 0;
 211         }
 212
 213         verbose(VERB_QUERY, "subnet: option registered (%d)",
 214                 env->cfg->client_subnet_opcode);
 215         /* Create new mesh state for all queries. */
 216         env->unique_mesh = 1;
 217         if(!edns_register_option(env->cfg->client_subnet_opcode,
 218                 env->cfg->client_subnet_always_forward /* bypass cache */,
 219                 0 /* no aggregation */, env)) {
 220                 log_err("subnet: could not register opcode");
 221                 ecs_whitelist_delete(sn_env->whitelist);
 222                 slabhash_delete(sn_env->subnet_msg_cache);
 223                 free(sn_env);
 224                 env->modinfo[id] = NULL;
 225                 return 0;
 226         }
 227         inplace_cb_register((void*)ecs_whitelist_check, inplace_cb_query, NULL,
 228                 env, id);
 229         inplace_cb_register((void*)ecs_edns_back_parsed,
 230                 inplace_cb_edns_back_parsed, NULL, env, id);
 231         inplace_cb_register((void*)ecs_query_response,
 232                 inplace_cb_query_response, NULL, env, id);
 233         lock_rw_init(&sn_env->biglock);
 234         return 1;
 235 }
 236
 237 void
 238 subnetmod_deinit(struct module_env *env, int id)
 239 {
 240         struct subnet_env *sn_env;
 241         if(!env || !env->modinfo[id])
 242                 return;
 243         sn_env = (struct subnet_env*)env->modinfo[id];
 244         lock_rw_destroy(&sn_env->biglock);
 245         inplace_cb_delete(env, inplace_cb_edns_back_parsed, id);
 246         inplace_cb_delete(env, inplace_cb_query, id);
 247         inplace_cb_delete(env, inplace_cb_query_response, id);
 248         ecs_whitelist_delete(sn_env->whitelist);
 249         slabhash_delete(sn_env->subnet_msg_cache);
 250         alloc_clear(&sn_env->alloc);
 251         free(sn_env);
 252         env->modinfo[id] = NULL;
 253 }
 254
 255 /** Tells client that upstream has no/improper support */
 256 static void
 257 cp_edns_bad_response(struct ecs_data *target, struct ecs_data *source)
 258 {
 259         target->subnet_scope_mask  = 0;
 260         target->subnet_source_mask = source->subnet_source_mask;
 261         target->subnet_addr_fam    = source->subnet_addr_fam;
 262         memcpy(target->subnet_addr, source->subnet_addr, INET6_SIZE);
 263         target->subnet_validdata = 1;
 264 }
 265
 266 static void
 267 delfunc(void *envptr, void *elemptr) {
 268         struct reply_info *elem = (struct reply_info *)elemptr;
 269         struct subnet_env *env = (struct subnet_env *)envptr;
 270         reply_info_parsedelete(elem, &env->alloc);
 271 }
 272
 273 static size_t
 274 sizefunc(void *elemptr) {
 275         struct reply_info *elem  = (struct reply_info *)elemptr;
 276         return sizeof (struct reply_info) - sizeof (struct rrset_ref)
 277                 + elem->rrset_count * sizeof (struct rrset_ref)
 278                 + elem->rrset_count * sizeof (struct ub_packed_rrset_key *);
 279 }
 280
 281 /**
 282  * Select tree from cache entry based on edns data.
 283  * If for address family not present it will create a new one.
 284  * NULL on failure to create. */
 285 static struct addrtree*
 286 get_tree(struct subnet_msg_cache_data *data, struct ecs_data *edns,
 287         struct subnet_env *env, struct config_file* cfg)
 288 {
 289         struct addrtree *tree;
 290         if (edns->subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP4) {
 291                 if (!data->tree4)
 292                         data->tree4 = addrtree_create(
 293                                 cfg->max_client_subnet_ipv4, &delfunc,
 294                                 &sizefunc, env, ECS_MAX_TREESIZE);
 295                 tree = data->tree4;
 296         } else {
 297                 if (!data->tree6)
 298                         data->tree6 = addrtree_create(
 299                                 cfg->max_client_subnet_ipv6, &delfunc,
 300                                 &sizefunc, env, ECS_MAX_TREESIZE);
 301                 tree = data->tree6;
 302         }
 303         return tree;
 304 }
 305
 306 static void
 307 update_cache(struct module_qstate *qstate, int id)
 308 {
 309         struct msgreply_entry *mrep_entry;
 310         struct addrtree *tree;
 311         struct reply_info *rep;
 312         struct query_info qinf;
 313         struct subnet_env *sne = qstate->env->modinfo[id];
 314         struct subnet_qstate *sq = (struct subnet_qstate*)qstate->minfo[id];
 315         struct slabhash *subnet_msg_cache = sne->subnet_msg_cache;
 316         struct ecs_data *edns = &sq->ecs_client_in;
 317         size_t i;
 318
 319         /* We already calculated hash upon lookup */
 320         hashvalue_type h = qstate->minfo[id] ?
 321                 ((struct subnet_qstate*)qstate->minfo[id])->qinfo_hash :
 322                 query_info_hash(&qstate->qinfo, qstate->query_flags);
 323         /* Step 1, general qinfo lookup */
 324         struct lruhash_entry *lru_entry = slabhash_lookup(subnet_msg_cache, h,
 325                 &qstate->qinfo, 1);
 326         int acquired_lock = (lru_entry != NULL);
 327         if (!lru_entry) {
 328                 qinf = qstate->qinfo;
 329                 qinf.qname = memdup(qstate->qinfo.qname,
 330                         qstate->qinfo.qname_len);
 331                 if(!qinf.qname) {
 332                         log_err("memdup failed");
 333                         return;
 334                 }
 335                 mrep_entry = query_info_entrysetup(&qinf, NULL, h);
 336                 free(qinf.qname); /* if qname 'consumed', it is set to NULL */
 337                 if (!mrep_entry) {
 338                         log_err("query_info_entrysetup failed");
 339                         return;
 340                 }
 341                 lru_entry = &mrep_entry->entry;
 342                 lock_rw_wrlock(&lru_entry->lock);
 343                 lru_entry->data = calloc(1,
 344                         sizeof(struct subnet_msg_cache_data));
 345                 if (!lru_entry->data) {
 346                         log_err("malloc failed");
 347                         return;
 348                 }
 349         }
 350         /* Step 2, find the correct tree */
 351         if (!(tree = get_tree(lru_entry->data, edns, sne, qstate->env->cfg))) {
 352                 if (acquired_lock) lock_rw_unlock(&lru_entry->lock);
 353                 log_err("Subnet cache insertion failed");
 354                 return;
 355         }
 356         lock_quick_lock(&sne->alloc.lock);
 357         rep = reply_info_copy(qstate->return_msg->rep, &sne->alloc, NULL);
 358         lock_quick_unlock(&sne->alloc.lock);
 359         if (!rep) {
 360                 if (acquired_lock) lock_rw_unlock(&lru_entry->lock);
 361                 log_err("Subnet cache insertion failed");
 362                 return;
 363         }
 364
 365         /* store RRsets */
 366         for(i=0; i<rep->rrset_count; i++) {
 367                 rep->ref[i].key = rep->rrsets[i];
 368                 rep->ref[i].id = rep->rrsets[i]->id;
 369         }
 370         reply_info_set_ttls(rep, *qstate->env->now);
 371         rep->flags |= (BIT_RA | BIT_QR); /* fix flags to be sensible for */
 372         rep->flags &= ~(BIT_AA | BIT_CD);/* a reply based on the cache   */
 373         addrtree_insert(tree, (addrkey_t*)edns->subnet_addr,
 374                 edns->subnet_source_mask,
 375                 sq->ecs_server_in.subnet_scope_mask, rep,
 376                 rep->ttl, *qstate->env->now);
 377         if (acquired_lock) {
 378                 lock_rw_unlock(&lru_entry->lock);
 379         } else {
 380                 lock_rw_unlock(&lru_entry->lock);
 381                 slabhash_insert(subnet_msg_cache, h, lru_entry, lru_entry->data,
 382                         NULL);
 383         }
 384 }
 385
 386 /** Lookup in cache and reply true iff reply is sent. */
 387 static int
 388 lookup_and_reply(struct module_qstate *qstate, int id, struct subnet_qstate *sq)
 389 {
 390         struct lruhash_entry *e;
 391         struct module_env *env = qstate->env;
 392         struct subnet_env *sne = (struct subnet_env*)env->modinfo[id];
 393         hashvalue_type h = query_info_hash(&qstate->qinfo, qstate->query_flags);
 394         struct subnet_msg_cache_data *data;
 395         struct ecs_data *ecs = &sq->ecs_client_in;
 396         struct addrtree *tree;
 397         struct addrnode *node;
 398         uint8_t scope;
 399
 400         memset(&sq->ecs_client_out, 0, sizeof(sq->ecs_client_out));
 401
 402         if (sq) sq->qinfo_hash = h; /* Might be useful on cache miss */
 403         e = slabhash_lookup(sne->subnet_msg_cache, h, &qstate->qinfo, 1);
 404         if (!e) return 0; /* qinfo not in cache */
 405         data = e->data;
 406         tree = (ecs->subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP4)?
 407                 data->tree4 : data->tree6;
 408         if (!tree) { /* qinfo in cache but not for this family */
 409                 lock_rw_unlock(&e->lock);
 410                 return 0;
 411         }
 412         node = addrtree_find(tree, (addrkey_t*)ecs->subnet_addr,
 413                 ecs->subnet_source_mask, *env->now);
 414         if (!node) { /* plain old cache miss */
 415                 lock_rw_unlock(&e->lock);
 416                 return 0;
 417         }
 418
 419         qstate->return_msg = tomsg(NULL, &qstate->qinfo,
 420                 (struct reply_info *)node->elem, qstate->region, *env->now,
 421                 env->scratch);
 422         scope = (uint8_t)node->scope;
 423         lock_rw_unlock(&e->lock);
 424
 425         if (!qstate->return_msg) { /* Failed allocation or expired TTL */
 426                 return 0;
 427         }
 428
 429         if (sq->subnet_downstream) { /* relay to interested client */
 430                 sq->ecs_client_out.subnet_scope_mask = scope;
 431                 sq->ecs_client_out.subnet_addr_fam = ecs->subnet_addr_fam;
 432                 sq->ecs_client_out.subnet_source_mask = ecs->subnet_source_mask;
 433                 memcpy(&sq->ecs_client_out.subnet_addr, &ecs->subnet_addr,
 434                         INET6_SIZE);
 435                 sq->ecs_client_out.subnet_validdata = 1;
 436         }
 437         return 1;
 438 }
 439
 440 /**
 441  * Test first bits of addresses for equality. Caller is responsible
 442  * for making sure that both a and b are at least net/8 octets long.
 443  * @param a: first address.
 444  * @param a: seconds address.
 445  * @param net: Number of bits to test.
 446  * @return: 1 if equal, 0 otherwise.
 447  */
 448 static int
 449 common_prefix(uint8_t *a, uint8_t *b, uint8_t net)
 450 {
 451         size_t n = (size_t)net / 8;
 452         return !memcmp(a, b, n) && ((net % 8) == 0 || a[n] == b[n]);
 453 }
 454
 455 static enum module_ext_state
 456 eval_response(struct module_qstate *qstate, int id, struct subnet_qstate *sq)
 457 {
 458         struct subnet_env *sne = qstate->env->modinfo[id];
 459
 460         struct ecs_data *c_in  = &sq->ecs_client_in; /* rcvd from client */
 461         struct ecs_data *c_out = &sq->ecs_client_out;/* will send to client */
 462         struct ecs_data *s_in  = &sq->ecs_server_in; /* rcvd from auth */
 463         struct ecs_data *s_out = &sq->ecs_server_out;/* sent to auth */
 464
 465         memset(c_out, 0, sizeof(*c_out));
 466
 467         if (!qstate->return_msg) {
 468                 /* already an answer and its not a message, but retain
 469                  * the actual rcode, instead of module_error, so send
 470                  * module_finished */
 471                 return module_finished;
 472         }
 473
 474         /* We have not asked for subnet data */
 475         if (!sq->subnet_sent) {
 476                 if (s_in->subnet_validdata)
 477                         verbose(VERB_QUERY, "subnet: received spurious data");
 478                 if (sq->subnet_downstream) /* Copy back to client */
 479                         cp_edns_bad_response(c_out, c_in);
 480                 return module_finished;
 481         }
 482
 483         /* subnet sent but nothing came back */
 484         if (!s_in->subnet_validdata) {
 485                 /* The authority indicated no support for edns subnet. As a
 486                  * consequence the answer ended up in the regular cache. It
 487                  * is still usefull to put it in the edns subnet cache for
 488                  * when a client explicitly asks for subnet specific answer. */
 489                 verbose(VERB_QUERY, "subnet: Authority indicates no support");
 490                 lock_rw_wrlock(&sne->biglock);
 491                 update_cache(qstate, id);
 492                 lock_rw_unlock(&sne->biglock);
 493                 if (sq->subnet_downstream)
 494                         cp_edns_bad_response(c_out, c_in);
 495                 return module_finished;
 496         }
 497
 498         /* Being here means we have asked for and got a subnet specific
 499          * answer. Also, the answer from the authority is not yet cached
 500          * anywhere. */
 501
 502         /* can we accept response? */
 503         if(s_out->subnet_addr_fam != s_in->subnet_addr_fam ||
 504                 s_out->subnet_source_mask != s_in->subnet_source_mask ||
 505                 !common_prefix(s_out->subnet_addr, s_in->subnet_addr,
 506                         s_out->subnet_source_mask))
 507         {
 508                 /* we can not accept, restart query without option */
 509                 verbose(VERB_QUERY, "subnet: forged data");
 510                 s_out->subnet_validdata = 0;
 511                 (void)edns_opt_list_remove(&qstate->edns_opts_back_out,
 512                         qstate->env->cfg->client_subnet_opcode);
 513                 sq->subnet_sent = 0;
 514                 return module_restart_next;
 515         }
 516
 517         lock_rw_wrlock(&sne->biglock);
 518         update_cache(qstate, id);
 519         sne->num_msg_nocache++;
 520         lock_rw_unlock(&sne->biglock);
 521
 522         if (sq->subnet_downstream) {
 523                 /* Client wants to see the answer, echo option back
 524                  * and adjust the scope. */
 525                 c_out->subnet_addr_fam = c_in->subnet_addr_fam;
 526                 c_out->subnet_source_mask = c_in->subnet_source_mask;
 527                 memcpy(&c_out->subnet_addr, &c_in->subnet_addr, INET6_SIZE);
 528                 c_out->subnet_scope_mask = s_in->subnet_scope_mask;
 529                 c_out->subnet_validdata = 1;
 530         }
 531         return module_finished;
 532 }
 533
 534 /** Parse EDNS opt data containing ECS */
 535 static int
 536 parse_subnet_option(struct edns_option* ecs_option, struct ecs_data* ecs)
 537 {
 538         memset(ecs, 0, sizeof(*ecs));
 539         if (ecs_option->opt_len < 4)
 540                 return 0;
 541
 542         ecs->subnet_addr_fam = sldns_read_uint16(ecs_option->opt_data);
 543         ecs->subnet_source_mask = ecs_option->opt_data[2];
 544         ecs->subnet_scope_mask = ecs_option->opt_data[3];
 545         /* remaining bytes indicate address */
 546
 547         /* validate input*/
 548         /* option length matches calculated length? */
 549         if (ecs_option->opt_len != (size_t)((ecs->subnet_source_mask+7)/8 + 4))
 550                 return 0;
 551         if (ecs_option->opt_len - 4 > INET6_SIZE || ecs_option->opt_len == 0)
 552                 return 0;
 553         if (ecs->subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP4) {
 554                 if (ecs->subnet_source_mask > 32 || ecs->subnet_scope_mask > 32)
 555                         return 0;
 556         } else if (ecs->subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP6) {
 557                 if (ecs->subnet_source_mask > 128 ||
 558                         ecs->subnet_scope_mask > 128)
 559                         return 0;
 560         } else
 561                 return 0;
 562
 563         /* valid ECS data, write to ecs_data */
 564         if (copy_clear(ecs->subnet_addr, INET6_SIZE, ecs_option->opt_data + 4,
 565                 ecs_option->opt_len - 4, ecs->subnet_source_mask))
 566                 return 0;
 567         ecs->subnet_validdata = 1;
 568         return 1;
 569 }
 570
 571 static void
 572 subnet_option_from_ss(struct sockaddr_storage *ss, struct ecs_data* ecs,
 573         struct config_file* cfg)
 574 {
 575         void* sinaddr;
 576
 577         /* Construct subnet option from original query */
 578         if(((struct sockaddr_in*)ss)->sin_family == AF_INET) {
 579                 ecs->subnet_source_mask = cfg->max_client_subnet_ipv4;
 580                 ecs->subnet_addr_fam = EDNSSUBNET_ADDRFAM_IP4;
 581                 sinaddr = &((struct sockaddr_in*)ss)->sin_addr;
 582                 if (!copy_clear( ecs->subnet_addr, INET6_SIZE,
 583                         (uint8_t *)sinaddr, INET_SIZE,
 584                         ecs->subnet_source_mask)) {
 585                         ecs->subnet_validdata = 1;
 586                 }
 587         }
 588 #ifdef INET6
 589         else {
 590                 ecs->subnet_source_mask = cfg->max_client_subnet_ipv6;
 591                 ecs->subnet_addr_fam = EDNSSUBNET_ADDRFAM_IP6;
 592                 sinaddr = &((struct sockaddr_in6*)ss)->sin6_addr;
 593                 if (!copy_clear( ecs->subnet_addr, INET6_SIZE,
 594                         (uint8_t *)sinaddr, INET6_SIZE,
 595                         ecs->subnet_source_mask)) {
 596                         ecs->subnet_validdata = 1;
 597                 }
 598         }
 599 #else
 600                         /* We don't know how to handle ip6, just pass */
 601 #endif /* INET6 */
 602 }
 603
 604 int
 605 ecs_query_response(struct module_qstate* qstate, struct dns_msg* response,
 606         int id, void* ATTR_UNUSED(cbargs))
 607 {
 608         struct subnet_qstate *sq;
 609
 610         if(!response || !(sq=(struct subnet_qstate*)qstate->minfo[id]))
 611                 return 1;
 612
 613         if(sq->subnet_sent &&
 614                 FLAGS_GET_RCODE(response->rep->flags) == LDNS_RCODE_REFUSED) {
 615                 /* REFUSED response to ECS query, remove ECS option. */
 616                 edns_opt_list_remove(&qstate->edns_opts_back_out,
 617                         qstate->env->cfg->client_subnet_opcode);
 618                 sq->subnet_sent = 0;
 619                 memset(&sq->ecs_server_out, 0, sizeof(sq->ecs_server_out));
 620         }
 621         return 1;
 622 }
 623
 624 int
 625 ecs_edns_back_parsed(struct module_qstate* qstate, int id,
 626         void* ATTR_UNUSED(cbargs))
 627 {
 628         struct subnet_qstate *sq;
 629         struct edns_option* ecs_opt;
 630
 631         if(!(sq=(struct subnet_qstate*)qstate->minfo[id]))
 632                 return 1;
 633         if((ecs_opt = edns_opt_list_find(
 634                 qstate->edns_opts_back_in,
 635                 qstate->env->cfg->client_subnet_opcode))) {
 636                 if(parse_subnet_option(ecs_opt, &sq->ecs_server_in) &&
 637                         sq->subnet_sent &&
 638                         sq->ecs_server_in.subnet_validdata)
 639                         /* Only skip global cache store if we sent an ECS option
 640                          * and received one back. Answers from non-whitelisted
 641                          * servers will end up in global cache. Answers for
 642                          * queries with 0 source will not (unless nameserver
 643                          * does not support ECS). */
 644                         qstate->no_cache_store = 1;
 645         }
 646
 647         return 1;
 648 }
 649
 650 void
 651 subnetmod_operate(struct module_qstate *qstate, enum module_ev event,
 652         int id, struct outbound_entry* outbound)
 653 {
 654         struct subnet_env *sne = qstate->env->modinfo[id];
 655         struct subnet_qstate *sq = (struct subnet_qstate*)qstate->minfo[id];
 656
 657         verbose(VERB_QUERY, "subnet[module %d] operate: extstate:%s "
 658                 "event:%s", id, strextstate(qstate->ext_state[id]),
 659                 strmodulevent(event));
 660         log_query_info(VERB_QUERY, "subnet operate: query", &qstate->qinfo);
 661
 662         if((event == module_event_new || event == module_event_pass) &&
 663                 sq == NULL) {
 664                 struct edns_option* ecs_opt;
 665                 if(!subnet_new_qstate(qstate, id)) {
 666                         qstate->return_msg = NULL;
 667                         qstate->ext_state[id] = module_finished;
 668                         return;
 669                 }
 670
 671                 sq = (struct subnet_qstate*)qstate->minfo[id];
 672
 673                 if((ecs_opt = edns_opt_list_find(
 674                         qstate->edns_opts_front_in,
 675                         qstate->env->cfg->client_subnet_opcode))) {
 676                         if(!parse_subnet_option(ecs_opt, &sq->ecs_client_in)) {
 677                                 /* Wrongly formatted ECS option. RFC mandates to
 678                                  * return FORMERROR. */
 679                                 qstate->return_rcode = LDNS_RCODE_FORMERR;
 680                                 qstate->ext_state[id] = module_finished;
 681                                 return;
 682                         }
 683                         sq->subnet_downstream = 1;
 684                 }
 685                 else if(qstate->mesh_info->reply_list) {
 686                         subnet_option_from_ss(
 687                                 &qstate->mesh_info->reply_list->query_reply.addr,
 688                                 &sq->ecs_client_in, qstate->env->cfg);
 689                 }
 690
 691                 if(sq->ecs_client_in.subnet_validdata == 0) {
 692                         /* No clients are interested in result or we could not
 693                          * parse it, we don't do client subnet */
 694                         sq->ecs_server_out.subnet_validdata = 0;
 695                         verbose(VERB_ALGO, "subnet: pass to next module");
 696                         qstate->ext_state[id] = module_wait_module;
 697                         return;
 698                 }
 699
 700                 lock_rw_wrlock(&sne->biglock);
 701                 if (lookup_and_reply(qstate, id, sq)) {
 702                         sne->num_msg_cache++;
 703                         lock_rw_unlock(&sne->biglock);
 704                         verbose(VERB_QUERY, "subnet: answered from cache");
 705                         qstate->ext_state[id] = module_finished;
 706
 707                         ecs_opt_list_append(&sq->ecs_client_out,
 708                                 &qstate->edns_opts_front_out, qstate);
 709                         return;
 710                 }
 711                 lock_rw_unlock(&sne->biglock);
 712
 713                 sq->ecs_server_out.subnet_addr_fam =
 714                         sq->ecs_client_in.subnet_addr_fam;
 715                 sq->ecs_server_out.subnet_source_mask =
 716                         sq->ecs_client_in.subnet_source_mask;
 717                 /* Limit source prefix to configured maximum */
 718                 if(sq->ecs_server_out.subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP4
 719                         && sq->ecs_server_out.subnet_source_mask >
 720                         qstate->env->cfg->max_client_subnet_ipv4)
 721                         sq->ecs_server_out.subnet_source_mask =
 722                                 qstate->env->cfg->max_client_subnet_ipv4;
 723                 else if(sq->ecs_server_out.subnet_addr_fam == EDNSSUBNET_ADDRFAM_IP6
 724                         && sq->ecs_server_out.subnet_source_mask >
 725                         qstate->env->cfg->max_client_subnet_ipv6)
 726                         sq->ecs_server_out.subnet_source_mask =
 727                                 qstate->env->cfg->max_client_subnet_ipv6;
 728                 /* Safe to copy completely, even if the source is limited by the
 729                  * configuration. ecs_opt_list_append() will limit the address.
 730                  * */
 731                 memcpy(&sq->ecs_server_out.subnet_addr,
 732                         sq->ecs_client_in.subnet_addr, INET6_SIZE);
 733                 sq->ecs_server_out.subnet_scope_mask = 0;
 734                 sq->ecs_server_out.subnet_validdata = 1;
 735                 if(sq->ecs_server_out.subnet_source_mask != 0 &&
 736                         qstate->env->cfg->client_subnet_always_forward &&
 737                         sq->subnet_downstream)
 738                         /* ECS specific data required, do not look at the global
 739                          * cache in other modules. */
 740                         qstate->no_cache_lookup = 1;
 741
 742                 /* pass request to next module */
 743                 verbose(VERB_ALGO,
 744                         "subnet: not found in cache. pass to next module");
 745                 qstate->ext_state[id] = module_wait_module;
 746                 return;
 747         }
 748         /* Query handed back by next module, we have a 'final' answer */
 749         if(sq && event == module_event_moddone) {
 750                 qstate->ext_state[id] = eval_response(qstate, id, sq);
 751                 if(qstate->ext_state[id] == module_finished &&
 752                         qstate->return_msg) {
 753                         ecs_opt_list_append(&sq->ecs_client_out,
 754                                 &qstate->edns_opts_front_out, qstate);
 755                 }
 756                 return;
 757         }
 758         if(sq && outbound) {
 759                 return;
 760         }
 761         /* We are being revisited */
 762         if(event == module_event_pass || event == module_event_new) {
 763                 /* Just pass it on, we already did the work */
 764                 verbose(VERB_ALGO, "subnet: pass to next module");
 765                 qstate->ext_state[id] = module_wait_module;
 766                 return;
 767         }
 768         if(!sq && (event == module_event_moddone)) {
 769                 /* during priming, module done but we never started */
 770                 qstate->ext_state[id] = module_finished;
 771                 return;
 772         }
 773         log_err("subnet: bad event %s", strmodulevent(event));
 774         qstate->ext_state[id] = module_error;
 775         return;
 776 }
 777
 778 void
 779 subnetmod_clear(struct module_qstate *ATTR_UNUSED(qstate),
 780         int ATTR_UNUSED(id))
 781 {
 782         /* qstate has no data outside region */
 783 }
 784
 785 void
 786 subnetmod_inform_super(struct module_qstate *ATTR_UNUSED(qstate),
 787         int ATTR_UNUSED(id), struct module_qstate *ATTR_UNUSED(super))
 788 {
 789         /* Not used */
 790 }
 791
 792 size_t
 793 subnetmod_get_mem(struct module_env *env, int id)
 794 {
 795         struct subnet_env *sn_env = env->modinfo[id];
 796         if (!sn_env) return 0;
 797         return sizeof(*sn_env) +
 798                 slabhash_get_mem(sn_env->subnet_msg_cache) +
 799                 ecs_whitelist_get_mem(sn_env->whitelist);
 800 }
 801
 802 /**
 803  * The module function block
 804  */
 805 static struct module_func_block subnetmod_block = {
 806         "subnet", &subnetmod_init, &subnetmod_deinit, &subnetmod_operate,
 807         &subnetmod_inform_super, &subnetmod_clear, &subnetmod_get_mem
 808 };
 809
 810 struct module_func_block*
 811 subnetmod_get_funcblock(void)
 812 {
 813         return &subnetmod_block;
 814 }
 815
 816 /** Wrappers for static functions to unit test */
 817 size_t
 818 unittest_wrapper_subnetmod_sizefunc(void *elemptr)
 819 {
 820         return sizefunc(elemptr);
 821 }
 822
 823 #endif  /* CLIENT_SUBNET */