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-rw-r--r--modules/stats/stats.c534
1 files changed, 534 insertions, 0 deletions
diff --git a/modules/stats/stats.c b/modules/stats/stats.c
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+++ b/modules/stats/stats.c
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+/* Copyright (C) CZ.NIC, z.s.p.o. <knot-resolver@labs.nic.cz>
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+/**
+ * @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 <lua.h>
+
+#include "lib/generic/trie.h"
+#include "lib/layer/iterate.h"
+#include "lib/rplan.h"
+#include "lib/module.h"
+#include "lib/layer.h"
+#include "lib/resolve.h"
+
+/* Defaults */
+#define VERBOSE_MSG(qry, ...) kr_log_q(qry, STATISTICS, __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(request,total) X(request,udp) X(request,tcp) X(request,xdp) \
+ X(request,dot) X(request,doh) X(request,internal) \
+ 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 {
+ trie_t *trie;
+ 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)
+{
+ /* 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 (kr_fails_assert(key_len >= 0))
+ 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.transport) {
+ 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 union kr_sockaddr *src = &req->upstream.transport->address;
+ switch (src->ip.sa_family) {
+ case AF_INET: memcpy(e, &src->ip4, sizeof(src->ip4)); break;
+ case AF_INET6: memcpy(e, &src->ip6, sizeof(src->ip6)); 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_transport(kr_layer_t *ctx)
+{
+ struct kr_request *req = ctx->req;
+ struct kr_module *module = ctx->api->data;
+ struct stat_data *data = module->data;
+
+ stat_const_add(data, metric_request_total, 1);
+ if (req->qsource.dst_addr == NULL) {
+ stat_const_add(data, metric_request_internal, 1);
+ return ctx->state;
+ }
+
+ /**
+ * Count each transport only once,
+ * i.e. DoT does not count as TCP and XDP does not count as UDP.
+ */
+ if (req->qsource.flags.http)
+ stat_const_add(data, metric_request_doh, 1);
+ else if (req->qsource.flags.tls)
+ stat_const_add(data, metric_request_dot, 1);
+ else if (req->qsource.flags.tcp)
+ stat_const_add(data, metric_request_tcp, 1);
+ else if (req->qsource.flags.xdp)
+ stat_const_add(data, metric_request_xdp, 1);
+ else
+ stat_const_add(data, metric_request_udp, 1);
+ 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 = &param->rplan;
+ struct stat_data *data = module->data;
+
+ collect_sample(data, rplan);
+ if (!param->answer) {
+ /* The answer is being dropped. TODO: perhaps add some stat for this? */
+ return ctx->state;
+ }
+
+ /* Collect data on final answer */
+ collect_answer(data, 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;
+ }
+ }
+ trie_val_t *trie_val = trie_get_ins(data->trie, pair, strlen(pair));
+ *trie_val = (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 */
+ trie_val_t *val = trie_get_try(data->trie, args, strlen(args));
+ if (!val) {
+ free(ret);
+ return NULL;
+ }
+ sprintf(ret, "%zu", (size_t) *val);
+ return ret;
+}
+
+/** Checks whether:
+ * - `key` starts with `prefix`; OR
+ * - The prefix is a wildcard, which is indicated by `prefix_len` being zero. */
+static inline bool key_matches_prefix(const char *key, size_t key_len,
+ const char *prefix, size_t prefix_len)
+{
+ return prefix_len == 0 || (prefix_len <= key_len && memcmp(key, prefix, prefix_len) == 0);
+}
+
+struct list_entry_context {
+ JsonNode *root; /**< JSON object into which matching entries will be inserted. */
+ const char *key_prefix; /**< The prefix against which entries will be matched. */
+ size_t key_prefix_len; /**< Prefix length. Prefix is a wildcard if zero. */
+};
+
+/** Inserts the entry with a matching key into the JSON object. */
+static int list_entry(const char *key, uint32_t key_len, trie_val_t *val, void *baton)
+{
+ struct list_entry_context *ctx = baton;
+ if (!key_matches_prefix(key, key_len, ctx->key_prefix, ctx->key_prefix_len))
+ return 0;
+ size_t number = (size_t) *val;
+ auto_free char *key_nt = strndup(key, key_len);
+ json_append_member(ctx->root, key_nt, json_mknumber(number));
+ return 0;
+}
+
+/**
+ * List observed metrics.
+ *
+ * Output: { key: val, ... }
+ */
+static char* stats_list(void *env, struct kr_module *module, const char *args)
+{
+ 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));
+ }
+ }
+ struct list_entry_context ctx = {
+ .root = root,
+ .key_prefix = args,
+ .key_prefix_len = args_len
+ };
+ struct stat_data *data = module->data;
+ trie_apply_with_key(data->trie, list_entry, &ctx);
+ 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;
+}
+
+KR_EXPORT
+int stats_init(struct kr_module *module)
+{
+ static kr_layer_api_t layer = {
+ .consume = &collect_rtt,
+ .finish = &collect,
+ .begin = &collect_transport,
+ };
+ /* Store module reference */
+ layer.data = module;
+ module->layer = &layer;
+
+ static const struct kr_prop props[] = {
+ { &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 }
+ };
+ module->props = props;
+
+ struct stat_data *data = calloc(1, sizeof(*data));
+ if (!data) {
+ return kr_error(ENOMEM);
+ }
+ data->trie = trie_create(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);
+ }
+ data->upstreams.q.len = UPSTREAMS_COUNT; /* signify we use the entries */
+ for (size_t i = 0; i < UPSTREAMS_COUNT; ++i) {
+ data->upstreams.q.at[i].sin6_family = AF_UNSPEC;
+ }
+ return kr_ok();
+}
+
+KR_EXPORT
+int stats_deinit(struct kr_module *module)
+{
+ struct stat_data *data = module->data;
+ if (data) {
+ trie_free(data->trie);
+ lru_free(data->queries.frequent);
+ array_clear(data->upstreams.q);
+ free(data);
+ }
+ return kr_ok();
+}
+
+KR_MODULE_EXPORT(stats)
+
+#undef VERBOSE_MSG
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