diff options
Diffstat (limited to 'modules/stats/stats.c')
| -rw-r--r-- | modules/stats/stats.c | 502 |
1 files changed, 502 insertions, 0 deletions
diff --git a/modules/stats/stats.c b/modules/stats/stats.c new file mode 100644 index 0000000..a2cf78e --- /dev/null +++ b/modules/stats/stats.c @@ -0,0 +1,502 @@ +/* Copyright (C) 2014-2017 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. + */ + +/** + * @file stats.c + * @brief Storage for various counters and metrics from query resolution. + * + * You can either reuse this module to compute statistics or store custom metrics + * in it via the extensions. + */ + +#include <libknot/packet/pkt.h> +#include <libknot/packet/wire.h> +#include <libknot/descriptor.h> +#include <ccan/json/json.h> +#include <contrib/cleanup.h> +#include <arpa/inet.h> + +#include "lib/layer/iterate.h" +#include "lib/rplan.h" +#include "lib/module.h" +#include "lib/layer.h" +#include "lib/resolve.h" + +/** @internal Compatibility wrapper for Lua < 5.2 */ +#if LUA_VERSION_NUM < 502 +#define lua_rawlen(L, obj) lua_objlen((L), (obj)) +#endif + +/* Defaults */ +#define VERBOSE_MSG(qry, ...) QRVERBOSE(qry, "stat", __VA_ARGS__) +#define FREQUENT_PSAMPLE 10 /* Sampling rate, 1 in N */ +#ifdef LRU_REP_SIZE + #define FREQUENT_COUNT LRU_REP_SIZE /* Size of frequent tables */ +#else + #define FREQUENT_COUNT 5000 /* Size of frequent tables */ +#endif +#ifndef UPSTREAMS_COUNT + #define UPSTREAMS_COUNT 512 /* Size of recent upstreams */ +#endif + +/** @cond internal Fixed-size map of predefined metrics. */ +#define CONST_METRICS(X) \ + X(answer,total) X(answer,noerror) X(answer,nodata) X(answer,nxdomain) X(answer,servfail) \ + X(answer,cached) X(answer,1ms) X(answer,10ms) X(answer,50ms) X(answer,100ms) \ + X(answer,250ms) X(answer,500ms) X(answer,1000ms) X(answer,1500ms) X(answer,slow) \ + X(answer,aa) X(answer,tc) X(answer,rd) X(answer,ra) X(answer, ad) X(answer,cd) \ + X(answer,edns0) X(answer,do) \ + X(query,edns) X(query,dnssec) \ + X(const,end) + +enum const_metric { + #define X(a,b) metric_ ## a ## _ ## b, + CONST_METRICS(X) + #undef X +}; +struct const_metric_elm { + const char *key; + size_t val; +}; +static struct const_metric_elm const_metrics[] = { + #define X(a,b) [metric_ ## a ## _ ## b] = { #a "." #b, 0 }, + CONST_METRICS(X) + #undef X +}; +/** @endcond */ + +/** @internal LRU hash of most frequent names. */ +typedef lru_t(unsigned) namehash_t; +typedef array_t(struct sockaddr_in6) addrlist_t; + +/** @internal Stats data structure. */ +struct stat_data { + map_t map; + struct { + namehash_t *frequent; + } queries; + struct { + addrlist_t q; + size_t head; + } upstreams; +}; + +/** @internal We don't store/publish port, repurpose it for RTT instead. */ +#define sin6_rtt sin6_port + +/** @internal Add to const map counter */ +static inline void stat_const_add(struct stat_data *data, enum const_metric key, ssize_t incr) +{ + const_metrics[key].val += incr; +} + +static int collect_answer(struct stat_data *data, knot_pkt_t *pkt) +{ + stat_const_add(data, metric_answer_total, 1); + /* Count per-rcode */ + switch(knot_wire_get_rcode(pkt->wire)) { + case KNOT_RCODE_NOERROR: + if (knot_wire_get_ancount(pkt->wire) > 0) + stat_const_add(data, metric_answer_noerror, 1); + else + stat_const_add(data, metric_answer_nodata, 1); + break; + case KNOT_RCODE_NXDOMAIN: stat_const_add(data, metric_answer_nxdomain, 1); break; + case KNOT_RCODE_SERVFAIL: stat_const_add(data, metric_answer_servfail, 1); break; + default: break; + } + + return kr_ok(); +} + +static inline int collect_key(char *key, const knot_dname_t *name, uint16_t type) +{ + memcpy(key, &type, sizeof(type)); + int key_len = knot_dname_to_wire((uint8_t *)key + sizeof(type), name, KNOT_DNAME_MAXLEN); + if (key_len < 0) { + return kr_error(key_len); + } + return key_len + sizeof(type); +} + +static void collect_sample(struct stat_data *data, struct kr_rplan *rplan, knot_pkt_t *pkt) +{ + /* Sample key = {[2] type, [1-255] owner} */ + char key[sizeof(uint16_t) + KNOT_DNAME_MAXLEN]; + for (size_t i = 0; i < rplan->resolved.len; ++i) { + /* Sample queries leading to iteration */ + struct kr_query *qry = rplan->resolved.at[i]; + if (qry->flags.CACHED) { + continue; + } + /* Consider 1 in N for frequent sampling. + * TODO: redesign the sampling approach. */ + if (kr_rand_coin(1, FREQUENT_PSAMPLE)) { + int key_len = collect_key(key, qry->sname, qry->stype); + if (key_len < 0) { + assert(false); + continue; + } + unsigned *count = lru_get_new(data->queries.frequent, key, key_len, NULL); + if (count) + *count += 1; + } + } +} + +static int collect_rtt(kr_layer_t *ctx, knot_pkt_t *pkt) +{ + struct kr_request *req = ctx->req; + struct kr_query *qry = req->current_query; + if (qry->flags.CACHED || !req->upstream.addr) { + return ctx->state; + } + + /* Push address and RTT to the ring buffer head */ + struct kr_module *module = ctx->api->data; + struct stat_data *data = module->data; + + /* Socket address is encoded into sockaddr_in6 struct that + * unions with sockaddr_in and differ in sa_family */ + struct sockaddr_in6 *e = &data->upstreams.q.at[data->upstreams.head]; + const struct sockaddr *src = req->upstream.addr; + switch (src->sa_family) { + case AF_INET: memcpy(e, src, sizeof(struct sockaddr_in)); break; + case AF_INET6: memcpy(e, src, sizeof(struct sockaddr_in6)); break; + default: return ctx->state; + } + /* Replace port number with the RTT information (cap is UINT16_MAX milliseconds) */ + e->sin6_rtt = req->upstream.rtt; + + /* Advance ring buffer head */ + data->upstreams.head = (data->upstreams.head + 1) % UPSTREAMS_COUNT; + return ctx->state; +} + +static int collect(kr_layer_t *ctx) +{ + struct kr_request *param = ctx->req; + struct kr_module *module = ctx->api->data; + struct kr_rplan *rplan = ¶m->rplan; + struct stat_data *data = module->data; + + /* Collect data on final answer */ + collect_answer(data, param->answer); + collect_sample(data, rplan, param->answer); + /* Count cached and unresolved */ + if (rplan->resolved.len > 0) { + /* Histogram of answer latency. */ + struct kr_query *first = rplan->resolved.at[0]; + uint64_t elapsed = kr_now() - first->timestamp_mono; + if (elapsed <= 1) { + stat_const_add(data, metric_answer_1ms, 1); + } else if (elapsed <= 10) { + stat_const_add(data, metric_answer_10ms, 1); + } else if (elapsed <= 50) { + stat_const_add(data, metric_answer_50ms, 1); + } else if (elapsed <= 100) { + stat_const_add(data, metric_answer_100ms, 1); + } else if (elapsed <= 250) { + stat_const_add(data, metric_answer_250ms, 1); + } else if (elapsed <= 500) { + stat_const_add(data, metric_answer_500ms, 1); + } else if (elapsed <= 1000) { + stat_const_add(data, metric_answer_1000ms, 1); + } else if (elapsed <= 1500) { + stat_const_add(data, metric_answer_1500ms, 1); + } else { + stat_const_add(data, metric_answer_slow, 1); + } + /* Observe the final query. */ + struct kr_query *last = kr_rplan_last(rplan); + stat_const_add(data, metric_answer_cached, last->flags.CACHED); + } + + /* Keep stats of all response header flags; + * these don't return bool, so that's why we use !! */ + stat_const_add(data, metric_answer_aa, !!knot_wire_get_aa(param->answer->wire)); + stat_const_add(data, metric_answer_tc, !!knot_wire_get_tc(param->answer->wire)); + stat_const_add(data, metric_answer_rd, !!knot_wire_get_rd(param->answer->wire)); + stat_const_add(data, metric_answer_ra, !!knot_wire_get_ra(param->answer->wire)); + stat_const_add(data, metric_answer_ad, !!knot_wire_get_ad(param->answer->wire)); + stat_const_add(data, metric_answer_cd, !!knot_wire_get_cd(param->answer->wire)); + + /* EDNS0 stats */ + stat_const_add(data, metric_answer_edns0, knot_pkt_has_edns(param->answer)); + stat_const_add(data, metric_answer_do, knot_pkt_has_dnssec(param->answer)); + + /* Query parameters and transport mode */ + /* + DEPRECATED + use new names metric_answer_edns0 and metric_answer_do + */ + stat_const_add(data, metric_query_edns, knot_pkt_has_edns(param->answer)); + stat_const_add(data, metric_query_dnssec, knot_pkt_has_dnssec(param->answer)); + + return ctx->state; +} + +/** + * Set nominal value of a key. + * + * Input: { key, val } + * + */ +static char* stats_set(void *env, struct kr_module *module, const char *args) +{ + if (args == NULL) + return NULL; + + struct stat_data *data = module->data; + + auto_free char *pair = strdup(args); + char *val = strchr(pair, ' '); + if (val) { + *val = '\0'; + size_t number = strtoul(val + 1, NULL, 10); + for (unsigned i = 0; i < metric_const_end; ++i) { + if (strcmp(const_metrics[i].key, pair) == 0) { + const_metrics[i].val = number; + return NULL; + } + } + map_set(&data->map, pair, (void *)number); + } + + return NULL; +} + +/** + * Retrieve metrics by key. + * + * Input: string key + * Output: number value + */ +static char* stats_get(void *env, struct kr_module *module, const char *args) +{ + if (args == NULL) + return NULL; + + struct stat_data *data = module->data; + + /* Expecting CHAR_BIT to be 8, this is a safe bet */ + char *ret = malloc(3 * sizeof(size_t) + 2); + if (!ret) { + return NULL; + } + + /* Check if it exists in const map. */ + for (unsigned i = 0; i < metric_const_end; ++i) { + if (strcmp(const_metrics[i].key, args) == 0) { + sprintf(ret, "%zu", const_metrics[i].val); + return ret; + } + } + /* Check in variable map */ + if (!map_contains(&data->map, args)) { + free(ret); + return NULL; + } + void *val = map_get(&data->map, args); + sprintf(ret, "%zu", (size_t) val); + return ret; +} + +static int list_entry(const char *key, void *val, void *baton) +{ + JsonNode *root = baton; + size_t number = (size_t) val; + json_append_member(root, key, json_mknumber(number)); + return 0; +} + +/** + * List observed metrics. + * + * Output: { key: val, ... } + */ +static char* stats_list(void *env, struct kr_module *module, const char *args) +{ + struct stat_data *data = module->data; + JsonNode *root = json_mkobject(); + /* Walk const metrics map */ + size_t args_len = args ? strlen(args) : 0; + for (unsigned i = 0; i < metric_const_end; ++i) { + struct const_metric_elm *elm = &const_metrics[i]; + if (!args || strncmp(elm->key, args, args_len) == 0) { + json_append_member(root, elm->key, json_mknumber(elm->val)); + } + } + map_walk_prefixed(&data->map, (args_len > 0) ? args : "", list_entry, root); + char *ret = json_encode(root); + json_delete(root); + return ret; +} + +/** @internal Helper for dump_list: add a single namehash_t item to JSON. */ +static enum lru_apply_do dump_value(const char *key, uint len, unsigned *val, void *baton) +{ + uint16_t key_type = 0; + /* Extract query name, type and counter */ + memcpy(&key_type, key, sizeof(key_type)); + KR_DNAME_GET_STR(key_name, (uint8_t *)key + sizeof(key_type)); + KR_RRTYPE_GET_STR(type_str, key_type); + + /* Convert to JSON object */ + JsonNode *json_val = json_mkobject(); + json_append_member(json_val, "count", json_mknumber(*val)); + json_append_member(json_val, "name", json_mkstring(key_name)); + json_append_member(json_val, "type", json_mkstring(type_str)); + json_append_element((JsonNode *)baton, json_val); + return LRU_APPLY_DO_NOTHING; // keep the item +} +/** + * List frequent names. + * + * Output: [{ count: <counter>, name: <qname>, type: <qtype>}, ... ] + */ +static char* dump_list(void *env, struct kr_module *module, const char *args, namehash_t *table) +{ + if (!table) { + return NULL; + } + JsonNode *root = json_mkarray(); + lru_apply(table, dump_value, root); + char *ret = json_encode(root); + json_delete(root); + return ret; +} + +static char* dump_frequent(void *env, struct kr_module *module, const char *args) +{ + struct stat_data *data = module->data; + return dump_list(env, module, args, data->queries.frequent); +} + +static char* clear_frequent(void *env, struct kr_module *module, const char *args) +{ + struct stat_data *data = module->data; + lru_reset(data->queries.frequent); + return NULL; +} + +static char* dump_upstreams(void *env, struct kr_module *module, const char *args) +{ + struct stat_data *data = module->data; + if (!data) { + return NULL; + } + + /* Walk the ring backwards until AF_UNSPEC or we hit head. */ + JsonNode *root = json_mkobject(); + size_t head = data->upstreams.head; + for (size_t i = 1; i < UPSTREAMS_COUNT; ++i) { + size_t h = (UPSTREAMS_COUNT + head - i) % UPSTREAMS_COUNT; + struct sockaddr_in6 *e = &data->upstreams.q.at[h]; + if (e->sin6_family == AF_UNSPEC) { + break; + } + /* Convert address to string */ + char addr_str[INET6_ADDRSTRLEN]; + const char *ret = inet_ntop(e->sin6_family, kr_inaddr((const struct sockaddr *)e), addr_str, sizeof(addr_str)); + if (!ret) { + break; + } + /* Append to map with an array encoding RTTs */ + JsonNode *json_val = json_find_member(root, addr_str); + if (!json_val) { + json_val = json_mkarray(); + json_append_member(root, addr_str, json_val); + } + json_append_element(json_val, json_mknumber(e->sin6_rtt)); + } + + /* Encode and return */ + char *ret = json_encode(root); + json_delete(root); + return ret; +} + +/* + * Module implementation. + */ + +KR_EXPORT +const kr_layer_api_t *stats_layer(struct kr_module *module) +{ + static kr_layer_api_t _layer = { + .consume = &collect_rtt, + .finish = &collect, + }; + /* Store module reference */ + _layer.data = module; + return &_layer; +} + +KR_EXPORT +int stats_init(struct kr_module *module) +{ + struct stat_data *data = malloc(sizeof(*data)); + if (!data) { + return kr_error(ENOMEM); + } + memset(data, 0, sizeof(*data)); + data->map = map_make(NULL); + module->data = data; + lru_create(&data->queries.frequent, FREQUENT_COUNT, NULL, NULL); + /* Initialize ring buffer of recently visited upstreams */ + array_init(data->upstreams.q); + if (array_reserve(data->upstreams.q, UPSTREAMS_COUNT) != 0) { + return kr_error(ENOMEM); + } + for (size_t i = 0; i < UPSTREAMS_COUNT; ++i) { + struct sockaddr *sa = (struct sockaddr *)&data->upstreams.q.at[i]; + sa->sa_family = AF_UNSPEC; + } + return kr_ok(); +} + +KR_EXPORT +int stats_deinit(struct kr_module *module) +{ + struct stat_data *data = module->data; + if (data) { + map_clear(&data->map); + lru_free(data->queries.frequent); + array_clear(data->upstreams.q); + free(data); + } + return kr_ok(); +} + +KR_EXPORT +struct kr_prop *stats_props(void) +{ + static struct kr_prop prop_list[] = { + { &stats_set, "set", "Set {key, val} metrics.", }, + { &stats_get, "get", "Get metrics for given key.", }, + { &stats_list, "list", "List observed metrics.", }, + { &dump_frequent, "frequent", "List most frequent queries.", }, + { &clear_frequent,"clear_frequent", "Clear frequent queries log.", }, + { &dump_upstreams, "upstreams", "List recently seen authoritatives.", }, + { NULL, NULL, NULL } + }; + return prop_list; +} + +KR_MODULE_EXPORT(stats) + +#undef VERBOSE_MSG |