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Diffstat (limited to 'usr.sbin/unbound/cachedb/cachedb.c')
| -rw-r--r-- | usr.sbin/unbound/cachedb/cachedb.c | 702 |
1 files changed, 702 insertions, 0 deletions
diff --git a/usr.sbin/unbound/cachedb/cachedb.c b/usr.sbin/unbound/cachedb/cachedb.c new file mode 100644 index 00000000000..76d9afa47c8 --- /dev/null +++ b/usr.sbin/unbound/cachedb/cachedb.c @@ -0,0 +1,702 @@ +/* + * cachedb/cachedb.c - cache from a database external to the program module + * + * Copyright (c) 2016, 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 + * + * This file contains a module that uses an external database to cache + * dns responses. + */ + +#include "config.h" +#ifdef USE_CACHEDB +#include "cachedb/cachedb.h" +#include "util/regional.h" +#include "util/net_help.h" +#include "util/config_file.h" +#include "util/data/msgreply.h" +#include "util/data/msgencode.h" +#include "services/cache/dns.h" +#include "validator/val_neg.h" +#include "validator/val_secalgo.h" +#include "iterator/iter_utils.h" +#include "sldns/parseutil.h" +#include "sldns/wire2str.h" +#include "sldns/sbuffer.h" + +#define CACHEDB_HASHSIZE 256 /* bit hash */ + +/** the unit test testframe for cachedb, its module state contains + * a cache for a couple queries (in memory). */ +struct testframe_moddata { + /** key for single stored data element, NULL if none */ + char* stored_key; + /** data for single stored data element, NULL if none */ + uint8_t* stored_data; + /** length of stored data */ + size_t stored_datalen; +}; + +static int +testframe_init(struct module_env* env, struct cachedb_env* cachedb_env) +{ + (void)env; + verbose(VERB_ALGO, "testframe_init"); + cachedb_env->backend_data = (void*)calloc(1, + sizeof(struct testframe_moddata)); + if(!cachedb_env->backend_data) { + log_err("out of memory"); + return 0; + } + return 1; +} + +static void +testframe_deinit(struct module_env* env, struct cachedb_env* cachedb_env) +{ + struct testframe_moddata* d = (struct testframe_moddata*) + cachedb_env->backend_data; + (void)env; + verbose(VERB_ALGO, "testframe_deinit"); + if(!d) + return; + free(d->stored_key); + free(d->stored_data); + free(d); +} + +static int +testframe_lookup(struct module_env* env, struct cachedb_env* cachedb_env, + char* key, struct sldns_buffer* result_buffer) +{ + struct testframe_moddata* d = (struct testframe_moddata*) + cachedb_env->backend_data; + (void)env; + verbose(VERB_ALGO, "testframe_lookup of %s", key); + if(d->stored_key && strcmp(d->stored_key, key) == 0) { + if(d->stored_datalen > sldns_buffer_capacity(result_buffer)) + return 0; /* too large */ + verbose(VERB_ALGO, "testframe_lookup found %d bytes", + (int)d->stored_datalen); + sldns_buffer_clear(result_buffer); + sldns_buffer_write(result_buffer, d->stored_data, + d->stored_datalen); + sldns_buffer_flip(result_buffer); + return 1; + } + return 0; +} + +static void +testframe_store(struct module_env* env, struct cachedb_env* cachedb_env, + char* key, uint8_t* data, size_t data_len) +{ + struct testframe_moddata* d = (struct testframe_moddata*) + cachedb_env->backend_data; + (void)env; + verbose(VERB_ALGO, "testframe_store %s (%d bytes)", key, (int)data_len); + + /* free old data element (if any) */ + free(d->stored_key); + d->stored_key = NULL; + free(d->stored_data); + d->stored_data = NULL; + d->stored_datalen = 0; + + d->stored_data = memdup(data, data_len); + if(!d->stored_data) { + log_err("out of memory"); + return; + } + d->stored_datalen = data_len; + d->stored_key = strdup(key); + if(!d->stored_key) { + free(d->stored_data); + d->stored_data = NULL; + d->stored_datalen = 0; + return; + } + /* (key,data) successfully stored */ +} + +/** The testframe backend is for unit tests */ +static struct cachedb_backend testframe_backend = { "testframe", + testframe_init, testframe_deinit, testframe_lookup, testframe_store +}; + +/** find a particular backend from possible backends */ +static struct cachedb_backend* +cachedb_find_backend(const char* str) +{ + if(strcmp(str, testframe_backend.name) == 0) + return &testframe_backend; + /* TODO add more backends here */ + return NULL; +} + +/** apply configuration to cachedb module 'global' state */ +static int +cachedb_apply_cfg(struct cachedb_env* cachedb_env, struct config_file* cfg) +{ + const char* backend_str = "testframe"; /* TODO get from cfg */ + if(backend_str && backend_str[0]) { + cachedb_env->backend = cachedb_find_backend(backend_str); + if(!cachedb_env->backend) { + log_err("cachedb: cannot find backend name '%s", + backend_str); + return NULL; + } + } + /* TODO see if more configuration needs to be applied or not */ + return 1; +} + +int +cachedb_init(struct module_env* env, int id) +{ + struct cachedb_env* cachedb_env = (struct cachedb_env*)calloc(1, + sizeof(struct cachedb_env)); + if(!cachedb_env) { + log_err("malloc failure"); + return 0; + } + env->modinfo[id] = (void*)cachedb_env; + if(!cachedb_apply_cfg(cachedb_env, env->cfg)) { + log_err("cachedb: could not apply configuration settings."); + return 0; + } + /* see if a backend is selected */ + if(!cachedb_env->backend || !cachedb_env->backend->name) + return 1; + if(!(*cachedb_env->backend->init)(env, cachedb_env)) { + log_err("cachedb: could not init %s backend", + cachedb_env->backend->name); + return 0; + } + cachedb_env->enabled = 1; + return 1; +} + +void +cachedb_deinit(struct module_env* env, int id) +{ + struct cachedb_env* cachedb_env; + if(!env || !env->modinfo[id]) + return; + cachedb_env = (struct cachedb_env*)env->modinfo[id]; + /* free contents */ + /* TODO */ + if(cachedb_env->enabled) { + (*cachedb_env->backend->deinit)(env, cachedb_env); + } + + free(cachedb_env); + env->modinfo[id] = NULL; +} + +/** new query for cachedb */ +static int +cachedb_new(struct module_qstate* qstate, int id) +{ + struct cachedb_qstate* iq = (struct cachedb_qstate*)regional_alloc( + qstate->region, sizeof(struct cachedb_qstate)); + qstate->minfo[id] = iq; + if(!iq) + return 0; + memset(iq, 0, sizeof(*iq)); + /* initialise it */ + /* TODO */ + + return 1; +} + +/** + * Return an error + * @param qstate: our query state + * @param id: module id + * @param rcode: error code (DNS errcode). + * @return: 0 for use by caller, to make notation easy, like: + * return error_response(..). + */ +static int +error_response(struct module_qstate* qstate, int id, int rcode) +{ + verbose(VERB_QUERY, "return error response %s", + sldns_lookup_by_id(sldns_rcodes, rcode)? + sldns_lookup_by_id(sldns_rcodes, rcode)->name:"??"); + qstate->return_rcode = rcode; + qstate->return_msg = NULL; + qstate->ext_state[id] = module_finished; + return 0; +} + +/** + * Hash the query name, type, class and dbacess-secret into lookup buffer. + * @param qstate: query state with query info + * and env->cfg with secret. + * @param buf: returned buffer with hash to lookup + * @param len: length of the buffer. + */ +static void +calc_hash(struct module_qstate* qstate, char* buf, size_t len) +{ + uint8_t clear[1024]; + size_t clen = 0; + uint8_t hash[CACHEDB_HASHSIZE/8]; + const char* hex = "0123456789ABCDEF"; + const char* secret = "default"; /* TODO: from qstate->env->cfg */ + size_t i; + + /* copy the hash info into the clear buffer */ + if(clen + qstate->qinfo.qname_len < sizeof(clear)) { + memmove(clear+clen, qstate->qinfo.qname, + qstate->qinfo.qname_len); + clen += qstate->qinfo.qname_len; + } + if(clen + 4 < sizeof(clear)) { + uint16_t t = htons(qstate->qinfo.qtype); + uint16_t c = htons(qstate->qinfo.qclass); + memmove(clear+clen, &t, 2); + memmove(clear+clen+2, &c, 2); + clen += 4; + } + if(secret && secret[0] && clen + strlen(secret) < sizeof(clear)) { + memmove(clear+clen, secret, strlen(secret)); + clen += strlen(secret); + } + + /* hash the buffer */ + secalgo_hash_sha256(clear, clen, hash); + memset(clear, 0, clen); + + /* hex encode output for portability (some online dbs need + * no nulls, no control characters, and so on) */ + log_assert(len >= sizeof(hash)*2 + 1); + (void)len; + for(i=0; i<sizeof(hash); i++) { + buf[i*2] = hex[(hash[i]&0xf0)>>4]; + buf[i*2+1] = hex[hash[i]&0x0f]; + } + buf[sizeof(hash)*2] = 0; +} + +/** convert data from return_msg into the data buffer */ +static int +prep_data(struct module_qstate* qstate, struct sldns_buffer* buf) +{ + uint64_t timestamp, expiry; + size_t oldlim; + struct edns_data edns; + memset(&edns, 0, sizeof(edns)); + edns.edns_present = 1; + edns.bits = EDNS_DO; + edns.ext_rcode = 0; + edns.edns_version = EDNS_ADVERTISED_VERSION; + edns.udp_size = EDNS_ADVERTISED_SIZE; + + if(!qstate->return_msg || !qstate->return_msg->rep) + return 0; + if(verbosity >= VERB_ALGO) + log_dns_msg("cachedb encoding", &qstate->return_msg->qinfo, + qstate->return_msg->rep); + if(!reply_info_answer_encode(&qstate->return_msg->qinfo, + qstate->return_msg->rep, 0, qstate->query_flags, + buf, 0, 1, qstate->env->scratch, 65535, &edns, 1, 0)) + return 0; + + /* TTLs in the return_msg are relative to time(0) so we have to + * store that, we also store the smallest ttl in the packet+time(0) + * as the packet expiry time */ + /* qstate->return_msg->rep->ttl contains that relative shortest ttl */ + timestamp = (uint64_t)*qstate->env->now; + expiry = timestamp + (uint64_t)qstate->return_msg->rep->ttl; + timestamp = htobe64(timestamp); + expiry = htobe64(expiry); + oldlim = sldns_buffer_limit(buf); + if(oldlim + sizeof(timestamp)+sizeof(expiry) >= + sldns_buffer_capacity(buf)) + return 0; /* doesn't fit. */ + sldns_buffer_set_limit(buf, oldlim + sizeof(timestamp)+sizeof(expiry)); + sldns_buffer_write_at(buf, oldlim, ×tamp, sizeof(timestamp)); + sldns_buffer_write_at(buf, oldlim+sizeof(timestamp), &expiry, + sizeof(expiry)); + + return 1; +} + +/** check expiry, return true if matches OK */ +static int +good_expiry_and_qinfo(struct module_qstate* qstate, struct sldns_buffer* buf) +{ + uint64_t expiry; + /* the expiry time is the last bytes of the buffer */ + if(sldns_buffer_limit(buf) < sizeof(expiry)) + return 0; + sldns_buffer_read_at(buf, sldns_buffer_limit(buf)-sizeof(expiry), + &expiry, sizeof(expiry)); + expiry = be64toh(expiry); + + if((time_t)expiry < *qstate->env->now) + return 0; + + return 1; +} + +/** convert dns message in buffer to return_msg */ +static int +parse_data(struct module_qstate* qstate, struct sldns_buffer* buf) +{ + struct msg_parse* prs; + struct edns_data edns; + uint64_t timestamp, expiry; + time_t adjust; + size_t lim = sldns_buffer_limit(buf); + if(lim < LDNS_HEADER_SIZE+sizeof(timestamp)+sizeof(expiry)) + return 0; /* too short */ + + /* remove timestamp and expiry from end */ + sldns_buffer_read_at(buf, lim-sizeof(expiry), &expiry, sizeof(expiry)); + sldns_buffer_read_at(buf, lim-sizeof(expiry)-sizeof(timestamp), + ×tamp, sizeof(timestamp)); + expiry = be64toh(expiry); + timestamp = be64toh(timestamp); + + /* parse DNS packet */ + regional_free_all(qstate->env->scratch); + prs = (struct msg_parse*)regional_alloc(qstate->env->scratch, + sizeof(struct msg_parse)); + if(!prs) + return 0; /* out of memory */ + memset(prs, 0, sizeof(*prs)); + memset(&edns, 0, sizeof(edns)); + sldns_buffer_set_limit(buf, lim - sizeof(expiry)-sizeof(timestamp)); + if(parse_packet(buf, prs, qstate->env->scratch) != LDNS_RCODE_NOERROR) { + sldns_buffer_set_limit(buf, lim); + return 0; + } + if(parse_extract_edns(prs, &edns, qstate->env->scratch) != + LDNS_RCODE_NOERROR) { + sldns_buffer_set_limit(buf, lim); + return 0; + } + + qstate->return_msg = dns_alloc_msg(buf, prs, qstate->region); + sldns_buffer_set_limit(buf, lim); + if(!qstate->return_msg) + return 0; + + qstate->return_rcode = LDNS_RCODE_NOERROR; + + /* see how much of the TTL expired, and remove it */ + adjust = *qstate->env->now - (time_t)timestamp; + verbose(VERB_ALGO, "cachedb msg adjusted down by %d", (int)adjust); + /*adjust_msg(qstate->return_msg, adjust);*/ + /* TODO: + msg->rep->ttl = r->ttl - adjust; + msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl); + for(i=0; i<d->count + d->rrsig_count; i++) { + if(d->rr_ttl[i] < adjust) + d->rr_ttl[i] = 0; + else d->rr_ttl[i] -= adjust; + } + if(d->ttl < adjust) + d->ttl = 0; + else d->ttl -= adjust; + */ + /* TODO */ + + return 0; +} + +/** + * Lookup the qstate.qinfo in extcache, store in qstate.return_msg. + * return true if lookup was successful. + */ +static int +cachedb_extcache_lookup(struct module_qstate* qstate, struct cachedb_env* ie) +{ + char key[(CACHEDB_HASHSIZE/8)*2+1]; + calc_hash(qstate, key, sizeof(key)); + + /* call backend to fetch data for key into scratch buffer */ + if( !(*ie->backend->lookup)(qstate->env, ie, key, + qstate->env->scratch_buffer)) { + return 0; + } + + /* check expiry date and check if query-data matches */ + if( !good_expiry_and_qinfo(qstate, qstate->env->scratch_buffer) ) { + return 0; + } + + /* parse dns message into return_msg */ + if( !parse_data(qstate, qstate->env->scratch_buffer) ) { + return 0; + } + return 1; +} + +/** + * Store the qstate.return_msg in extcache for key qstate.info + */ +static void +cachedb_extcache_store(struct module_qstate* qstate, struct cachedb_env* ie) +{ + char key[(CACHEDB_HASHSIZE/8)*2+1]; + calc_hash(qstate, key, sizeof(key)); + + /* prepare data in scratch buffer */ + if(!prep_data(qstate, qstate->env->scratch_buffer)) + return; + + /* call backend */ + (*ie->backend->store)(qstate->env, ie, key, + sldns_buffer_begin(qstate->env->scratch_buffer), + sldns_buffer_limit(qstate->env->scratch_buffer)); +} + +/** + * See if unbound's internal cache can answer the query + */ +static int +cachedb_intcache_lookup(struct module_qstate* qstate) +{ + struct dns_msg* msg; + msg = dns_cache_lookup(qstate->env, qstate->qinfo.qname, + qstate->qinfo.qname_len, qstate->qinfo.qtype, + qstate->qinfo.qclass, qstate->query_flags, + qstate->region, qstate->env->scratch); + if(!msg && qstate->env->neg_cache) { + /* lookup in negative cache; may result in + * NOERROR/NODATA or NXDOMAIN answers that need validation */ + msg = val_neg_getmsg(qstate->env->neg_cache, &qstate->qinfo, + qstate->region, qstate->env->rrset_cache, + qstate->env->scratch_buffer, + *qstate->env->now, 1/*add SOA*/, NULL); + } + if(!msg) + return 0; + /* this is the returned msg */ + qstate->return_rcode = LDNS_RCODE_NOERROR; + qstate->return_msg = msg; + return 1; +} + +/** + * Store query into the internal cache of unbound. + */ +static void +cachedb_intcache_store(struct module_qstate* qstate) +{ + if(!qstate->return_msg) + return; + (void)dns_cache_store(qstate->env, &qstate->qinfo, + qstate->return_msg->rep, 0, qstate->prefetch_leeway, 0, + qstate->region, qstate->query_flags); +} + +/** + * Handle a cachedb module event with a query + * @param qstate: query state (from the mesh), passed between modules. + * contains qstate->env module environment with global caches and so on. + * @param iq: query state specific for this module. per-query. + * @param ie: environment specific for this module. global. + * @param id: module id. + */ +static void +cachedb_handle_query(struct module_qstate* qstate, + struct cachedb_qstate* ATTR_UNUSED(iq), + struct cachedb_env* ie, int id) +{ + /* check if we are enabled, and skip if so */ + if(!ie->enabled) { + /* pass request to next module */ + qstate->ext_state[id] = module_wait_module; + return; + } + + if(qstate->blacklist) { + /* cache is blacklisted */ + /* pass request to next module */ + qstate->ext_state[id] = module_wait_module; + return; + } + + /* lookup inside unbound's internal cache */ + if(cachedb_intcache_lookup(qstate)) { + if(verbosity >= VERB_ALGO) + log_dns_msg("cachedb internal cache lookup", + &qstate->return_msg->qinfo, + qstate->return_msg->rep); + /* we are done with the query */ + qstate->ext_state[id] = module_finished; + return; + } + + /* ask backend cache to see if we have data */ + if(cachedb_extcache_lookup(qstate, ie)) { + if(verbosity >= VERB_ALGO) + log_dns_msg(ie->backend->name, + &qstate->return_msg->qinfo, + qstate->return_msg->rep); + /* store this result in internal cache */ + cachedb_intcache_store(qstate); + /* we are done with the query */ + qstate->ext_state[id] = module_finished; + return; + } + + /* no cache fetches */ + /* pass request to next module */ + qstate->ext_state[id] = module_wait_module; +} + +/** + * Handle a cachedb module event with a response from the iterator. + * @param qstate: query state (from the mesh), passed between modules. + * contains qstate->env module environment with global caches and so on. + * @param iq: query state specific for this module. per-query. + * @param ie: environment specific for this module. global. + * @param id: module id. + */ +static void +cachedb_handle_response(struct module_qstate* qstate, + struct cachedb_qstate* ATTR_UNUSED(iq), struct cachedb_env* ie, int id) +{ + /* check if we are enabled, and skip if not */ + if(!ie->enabled) { + /* we are done with the query */ + qstate->ext_state[id] = module_finished; + return; + } + + /* store the item into the backend cache */ + cachedb_extcache_store(qstate, ie); + + /* we are done with the query */ + qstate->ext_state[id] = module_finished; +} + +void +cachedb_operate(struct module_qstate* qstate, enum module_ev event, int id, + struct outbound_entry* outbound) +{ + struct cachedb_env* ie = (struct cachedb_env*)qstate->env->modinfo[id]; + struct cachedb_qstate* iq = (struct cachedb_qstate*)qstate->minfo[id]; + verbose(VERB_QUERY, "cachedb[module %d] operate: extstate:%s event:%s", + id, strextstate(qstate->ext_state[id]), strmodulevent(event)); + if(iq) log_query_info(VERB_QUERY, "cachedb operate: query", + &qstate->qinfo); + + /* perform cachedb state machine */ + if((event == module_event_new || event == module_event_pass) && + iq == NULL) { + if(!cachedb_new(qstate, id)) { + (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); + return; + } + iq = (struct cachedb_qstate*)qstate->minfo[id]; + } + if(iq && (event == module_event_pass || event == module_event_new)) { + cachedb_handle_query(qstate, iq, ie, id); + return; + } + if(iq && (event == module_event_moddone)) { + cachedb_handle_response(qstate, iq, ie, id); + return; + } + if(iq && outbound) { + /* cachedb does not need to process responses at this time + * ignore it. + cachedb_process_response(qstate, iq, ie, id, outbound, event); + */ + return; + } + if(event == module_event_error) { + verbose(VERB_ALGO, "got called with event error, giving up"); + (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); + return; + } + + log_err("bad event for cachedb"); + (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); +} + +void +cachedb_inform_super(struct module_qstate* ATTR_UNUSED(qstate), + int ATTR_UNUSED(id), struct module_qstate* ATTR_UNUSED(super)) +{ + /* cachedb does not use subordinate requests at this time */ + verbose(VERB_ALGO, "cachedb inform_super was called"); +} + +void +cachedb_clear(struct module_qstate* qstate, int id) +{ + struct cachedb_qstate* iq; + if(!qstate) + return; + iq = (struct cachedb_qstate*)qstate->minfo[id]; + if(iq) { + /* free contents of iq */ + /* TODO */ + } + qstate->minfo[id] = NULL; +} + +size_t +cachedb_get_mem(struct module_env* env, int id) +{ + struct cachedb_env* ie = (struct cachedb_env*)env->modinfo[id]; + if(!ie) + return 0; + return sizeof(*ie); /* TODO - more mem */ +} + +/** + * The cachedb function block + */ +static struct module_func_block cachedb_block = { + "cachedb", + &cachedb_init, &cachedb_deinit, &cachedb_operate, + &cachedb_inform_super, &cachedb_clear, &cachedb_get_mem +}; + +struct module_func_block* +cachedb_get_funcblock(void) +{ + return &cachedb_block; +} +#endif /* USE_CACHEDB */ |