Mercurial > hg > nginx
view src/core/ngx_hash.c @ 7312:54683f650cbd
Resolver: retry sending queries on errors (ticket #1511).
Errors when sending UDP datagrams can happen, e.g., when local IP address
changes (see fa0e093b64d7), or an unavailable DNS server on the LAN can cause
send() to fail with EHOSTDOWN on BSD systems. If this happens during
initial query, retry sending immediately, to a different DNS server when
possible. If this is not enough, allow normal resend to happen by ignoring
the return code of the second ngx_resolver_send_query() call, much like we
do in ngx_resolver_resend().
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 05 Jul 2018 22:21:14 +0300 |
parents | 7fc16ff7ddc4 |
children | c3f60d618c17 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> void * ngx_hash_find(ngx_hash_t *hash, ngx_uint_t key, u_char *name, size_t len) { ngx_uint_t i; ngx_hash_elt_t *elt; #if 0 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0, "hf:\"%*s\"", len, name); #endif elt = hash->buckets[key % hash->size]; if (elt == NULL) { return NULL; } while (elt->value) { if (len != (size_t) elt->len) { goto next; } for (i = 0; i < len; i++) { if (name[i] != elt->name[i]) { goto next; } } return elt->value; next: elt = (ngx_hash_elt_t *) ngx_align_ptr(&elt->name[0] + elt->len, sizeof(void *)); continue; } return NULL; } void * ngx_hash_find_wc_head(ngx_hash_wildcard_t *hwc, u_char *name, size_t len) { void *value; ngx_uint_t i, n, key; #if 0 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0, "wch:\"%*s\"", len, name); #endif n = len; while (n) { if (name[n - 1] == '.') { break; } n--; } key = 0; for (i = n; i < len; i++) { key = ngx_hash(key, name[i]); } #if 0 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0, "key:\"%ui\"", key); #endif value = ngx_hash_find(&hwc->hash, key, &name[n], len - n); #if 0 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0, "value:\"%p\"", value); #endif if (value) { /* * the 2 low bits of value have the special meaning: * 00 - value is data pointer for both "example.com" * and "*.example.com"; * 01 - value is data pointer for "*.example.com" only; * 10 - value is pointer to wildcard hash allowing * both "example.com" and "*.example.com"; * 11 - value is pointer to wildcard hash allowing * "*.example.com" only. */ if ((uintptr_t) value & 2) { if (n == 0) { /* "example.com" */ if ((uintptr_t) value & 1) { return NULL; } hwc = (ngx_hash_wildcard_t *) ((uintptr_t) value & (uintptr_t) ~3); return hwc->value; } hwc = (ngx_hash_wildcard_t *) ((uintptr_t) value & (uintptr_t) ~3); value = ngx_hash_find_wc_head(hwc, name, n - 1); if (value) { return value; } return hwc->value; } if ((uintptr_t) value & 1) { if (n == 0) { /* "example.com" */ return NULL; } return (void *) ((uintptr_t) value & (uintptr_t) ~3); } return value; } return hwc->value; } void * ngx_hash_find_wc_tail(ngx_hash_wildcard_t *hwc, u_char *name, size_t len) { void *value; ngx_uint_t i, key; #if 0 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0, "wct:\"%*s\"", len, name); #endif key = 0; for (i = 0; i < len; i++) { if (name[i] == '.') { break; } key = ngx_hash(key, name[i]); } if (i == len) { return NULL; } #if 0 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0, "key:\"%ui\"", key); #endif value = ngx_hash_find(&hwc->hash, key, name, i); #if 0 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0, "value:\"%p\"", value); #endif if (value) { /* * the 2 low bits of value have the special meaning: * 00 - value is data pointer; * 11 - value is pointer to wildcard hash allowing "example.*". */ if ((uintptr_t) value & 2) { i++; hwc = (ngx_hash_wildcard_t *) ((uintptr_t) value & (uintptr_t) ~3); value = ngx_hash_find_wc_tail(hwc, &name[i], len - i); if (value) { return value; } return hwc->value; } return value; } return hwc->value; } void * ngx_hash_find_combined(ngx_hash_combined_t *hash, ngx_uint_t key, u_char *name, size_t len) { void *value; if (hash->hash.buckets) { value = ngx_hash_find(&hash->hash, key, name, len); if (value) { return value; } } if (len == 0) { return NULL; } if (hash->wc_head && hash->wc_head->hash.buckets) { value = ngx_hash_find_wc_head(hash->wc_head, name, len); if (value) { return value; } } if (hash->wc_tail && hash->wc_tail->hash.buckets) { value = ngx_hash_find_wc_tail(hash->wc_tail, name, len); if (value) { return value; } } return NULL; } #define NGX_HASH_ELT_SIZE(name) \ (sizeof(void *) + ngx_align((name)->key.len + 2, sizeof(void *))) ngx_int_t ngx_hash_init(ngx_hash_init_t *hinit, ngx_hash_key_t *names, ngx_uint_t nelts) { u_char *elts; size_t len; u_short *test; ngx_uint_t i, n, key, size, start, bucket_size; ngx_hash_elt_t *elt, **buckets; if (hinit->max_size == 0) { ngx_log_error(NGX_LOG_EMERG, hinit->pool->log, 0, "could not build %s, you should " "increase %s_max_size: %i", hinit->name, hinit->name, hinit->max_size); return NGX_ERROR; } for (n = 0; n < nelts; n++) { if (hinit->bucket_size < NGX_HASH_ELT_SIZE(&names[n]) + sizeof(void *)) { ngx_log_error(NGX_LOG_EMERG, hinit->pool->log, 0, "could not build %s, you should " "increase %s_bucket_size: %i", hinit->name, hinit->name, hinit->bucket_size); return NGX_ERROR; } } test = ngx_alloc(hinit->max_size * sizeof(u_short), hinit->pool->log); if (test == NULL) { return NGX_ERROR; } bucket_size = hinit->bucket_size - sizeof(void *); start = nelts / (bucket_size / (2 * sizeof(void *))); start = start ? start : 1; if (hinit->max_size > 10000 && nelts && hinit->max_size / nelts < 100) { start = hinit->max_size - 1000; } for (size = start; size <= hinit->max_size; size++) { ngx_memzero(test, size * sizeof(u_short)); for (n = 0; n < nelts; n++) { if (names[n].key.data == NULL) { continue; } key = names[n].key_hash % size; test[key] = (u_short) (test[key] + NGX_HASH_ELT_SIZE(&names[n])); #if 0 ngx_log_error(NGX_LOG_ALERT, hinit->pool->log, 0, "%ui: %ui %ui \"%V\"", size, key, test[key], &names[n].key); #endif if (test[key] > (u_short) bucket_size) { goto next; } } goto found; next: continue; } size = hinit->max_size; ngx_log_error(NGX_LOG_WARN, hinit->pool->log, 0, "could not build optimal %s, you should increase " "either %s_max_size: %i or %s_bucket_size: %i; " "ignoring %s_bucket_size", hinit->name, hinit->name, hinit->max_size, hinit->name, hinit->bucket_size, hinit->name); found: for (i = 0; i < size; i++) { test[i] = sizeof(void *); } for (n = 0; n < nelts; n++) { if (names[n].key.data == NULL) { continue; } key = names[n].key_hash % size; test[key] = (u_short) (test[key] + NGX_HASH_ELT_SIZE(&names[n])); } len = 0; for (i = 0; i < size; i++) { if (test[i] == sizeof(void *)) { continue; } test[i] = (u_short) (ngx_align(test[i], ngx_cacheline_size)); len += test[i]; } if (hinit->hash == NULL) { hinit->hash = ngx_pcalloc(hinit->pool, sizeof(ngx_hash_wildcard_t) + size * sizeof(ngx_hash_elt_t *)); if (hinit->hash == NULL) { ngx_free(test); return NGX_ERROR; } buckets = (ngx_hash_elt_t **) ((u_char *) hinit->hash + sizeof(ngx_hash_wildcard_t)); } else { buckets = ngx_pcalloc(hinit->pool, size * sizeof(ngx_hash_elt_t *)); if (buckets == NULL) { ngx_free(test); return NGX_ERROR; } } elts = ngx_palloc(hinit->pool, len + ngx_cacheline_size); if (elts == NULL) { ngx_free(test); return NGX_ERROR; } elts = ngx_align_ptr(elts, ngx_cacheline_size); for (i = 0; i < size; i++) { if (test[i] == sizeof(void *)) { continue; } buckets[i] = (ngx_hash_elt_t *) elts; elts += test[i]; } for (i = 0; i < size; i++) { test[i] = 0; } for (n = 0; n < nelts; n++) { if (names[n].key.data == NULL) { continue; } key = names[n].key_hash % size; elt = (ngx_hash_elt_t *) ((u_char *) buckets[key] + test[key]); elt->value = names[n].value; elt->len = (u_short) names[n].key.len; ngx_strlow(elt->name, names[n].key.data, names[n].key.len); test[key] = (u_short) (test[key] + NGX_HASH_ELT_SIZE(&names[n])); } for (i = 0; i < size; i++) { if (buckets[i] == NULL) { continue; } elt = (ngx_hash_elt_t *) ((u_char *) buckets[i] + test[i]); elt->value = NULL; } ngx_free(test); hinit->hash->buckets = buckets; hinit->hash->size = size; #if 0 for (i = 0; i < size; i++) { ngx_str_t val; ngx_uint_t key; elt = buckets[i]; if (elt == NULL) { ngx_log_error(NGX_LOG_ALERT, hinit->pool->log, 0, "%ui: NULL", i); continue; } while (elt->value) { val.len = elt->len; val.data = &elt->name[0]; key = hinit->key(val.data, val.len); ngx_log_error(NGX_LOG_ALERT, hinit->pool->log, 0, "%ui: %p \"%V\" %ui", i, elt, &val, key); elt = (ngx_hash_elt_t *) ngx_align_ptr(&elt->name[0] + elt->len, sizeof(void *)); } } #endif return NGX_OK; } ngx_int_t ngx_hash_wildcard_init(ngx_hash_init_t *hinit, ngx_hash_key_t *names, ngx_uint_t nelts) { size_t len, dot_len; ngx_uint_t i, n, dot; ngx_array_t curr_names, next_names; ngx_hash_key_t *name, *next_name; ngx_hash_init_t h; ngx_hash_wildcard_t *wdc; if (ngx_array_init(&curr_names, hinit->temp_pool, nelts, sizeof(ngx_hash_key_t)) != NGX_OK) { return NGX_ERROR; } if (ngx_array_init(&next_names, hinit->temp_pool, nelts, sizeof(ngx_hash_key_t)) != NGX_OK) { return NGX_ERROR; } for (n = 0; n < nelts; n = i) { #if 0 ngx_log_error(NGX_LOG_ALERT, hinit->pool->log, 0, "wc0: \"%V\"", &names[n].key); #endif dot = 0; for (len = 0; len < names[n].key.len; len++) { if (names[n].key.data[len] == '.') { dot = 1; break; } } name = ngx_array_push(&curr_names); if (name == NULL) { return NGX_ERROR; } name->key.len = len; name->key.data = names[n].key.data; name->key_hash = hinit->key(name->key.data, name->key.len); name->value = names[n].value; #if 0 ngx_log_error(NGX_LOG_ALERT, hinit->pool->log, 0, "wc1: \"%V\" %ui", &name->key, dot); #endif dot_len = len + 1; if (dot) { len++; } next_names.nelts = 0; if (names[n].key.len != len) { next_name = ngx_array_push(&next_names); if (next_name == NULL) { return NGX_ERROR; } next_name->key.len = names[n].key.len - len; next_name->key.data = names[n].key.data + len; next_name->key_hash = 0; next_name->value = names[n].value; #if 0 ngx_log_error(NGX_LOG_ALERT, hinit->pool->log, 0, "wc2: \"%V\"", &next_name->key); #endif } for (i = n + 1; i < nelts; i++) { if (ngx_strncmp(names[n].key.data, names[i].key.data, len) != 0) { break; } if (!dot && names[i].key.len > len && names[i].key.data[len] != '.') { break; } next_name = ngx_array_push(&next_names); if (next_name == NULL) { return NGX_ERROR; } next_name->key.len = names[i].key.len - dot_len; next_name->key.data = names[i].key.data + dot_len; next_name->key_hash = 0; next_name->value = names[i].value; #if 0 ngx_log_error(NGX_LOG_ALERT, hinit->pool->log, 0, "wc3: \"%V\"", &next_name->key); #endif } if (next_names.nelts) { h = *hinit; h.hash = NULL; if (ngx_hash_wildcard_init(&h, (ngx_hash_key_t *) next_names.elts, next_names.nelts) != NGX_OK) { return NGX_ERROR; } wdc = (ngx_hash_wildcard_t *) h.hash; if (names[n].key.len == len) { wdc->value = names[n].value; } name->value = (void *) ((uintptr_t) wdc | (dot ? 3 : 2)); } else if (dot) { name->value = (void *) ((uintptr_t) name->value | 1); } } if (ngx_hash_init(hinit, (ngx_hash_key_t *) curr_names.elts, curr_names.nelts) != NGX_OK) { return NGX_ERROR; } return NGX_OK; } ngx_uint_t ngx_hash_key(u_char *data, size_t len) { ngx_uint_t i, key; key = 0; for (i = 0; i < len; i++) { key = ngx_hash(key, data[i]); } return key; } ngx_uint_t ngx_hash_key_lc(u_char *data, size_t len) { ngx_uint_t i, key; key = 0; for (i = 0; i < len; i++) { key = ngx_hash(key, ngx_tolower(data[i])); } return key; } ngx_uint_t ngx_hash_strlow(u_char *dst, u_char *src, size_t n) { ngx_uint_t key; key = 0; while (n--) { *dst = ngx_tolower(*src); key = ngx_hash(key, *dst); dst++; src++; } return key; } ngx_int_t ngx_hash_keys_array_init(ngx_hash_keys_arrays_t *ha, ngx_uint_t type) { ngx_uint_t asize; if (type == NGX_HASH_SMALL) { asize = 4; ha->hsize = 107; } else { asize = NGX_HASH_LARGE_ASIZE; ha->hsize = NGX_HASH_LARGE_HSIZE; } if (ngx_array_init(&ha->keys, ha->temp_pool, asize, sizeof(ngx_hash_key_t)) != NGX_OK) { return NGX_ERROR; } if (ngx_array_init(&ha->dns_wc_head, ha->temp_pool, asize, sizeof(ngx_hash_key_t)) != NGX_OK) { return NGX_ERROR; } if (ngx_array_init(&ha->dns_wc_tail, ha->temp_pool, asize, sizeof(ngx_hash_key_t)) != NGX_OK) { return NGX_ERROR; } ha->keys_hash = ngx_pcalloc(ha->temp_pool, sizeof(ngx_array_t) * ha->hsize); if (ha->keys_hash == NULL) { return NGX_ERROR; } ha->dns_wc_head_hash = ngx_pcalloc(ha->temp_pool, sizeof(ngx_array_t) * ha->hsize); if (ha->dns_wc_head_hash == NULL) { return NGX_ERROR; } ha->dns_wc_tail_hash = ngx_pcalloc(ha->temp_pool, sizeof(ngx_array_t) * ha->hsize); if (ha->dns_wc_tail_hash == NULL) { return NGX_ERROR; } return NGX_OK; } ngx_int_t ngx_hash_add_key(ngx_hash_keys_arrays_t *ha, ngx_str_t *key, void *value, ngx_uint_t flags) { size_t len; u_char *p; ngx_str_t *name; ngx_uint_t i, k, n, skip, last; ngx_array_t *keys, *hwc; ngx_hash_key_t *hk; last = key->len; if (flags & NGX_HASH_WILDCARD_KEY) { /* * supported wildcards: * "*.example.com", ".example.com", and "www.example.*" */ n = 0; for (i = 0; i < key->len; i++) { if (key->data[i] == '*') { if (++n > 1) { return NGX_DECLINED; } } if (key->data[i] == '.' && key->data[i + 1] == '.') { return NGX_DECLINED; } if (key->data[i] == '\0') { return NGX_DECLINED; } } if (key->len > 1 && key->data[0] == '.') { skip = 1; goto wildcard; } if (key->len > 2) { if (key->data[0] == '*' && key->data[1] == '.') { skip = 2; goto wildcard; } if (key->data[i - 2] == '.' && key->data[i - 1] == '*') { skip = 0; last -= 2; goto wildcard; } } if (n) { return NGX_DECLINED; } } /* exact hash */ k = 0; for (i = 0; i < last; i++) { if (!(flags & NGX_HASH_READONLY_KEY)) { key->data[i] = ngx_tolower(key->data[i]); } k = ngx_hash(k, key->data[i]); } k %= ha->hsize; /* check conflicts in exact hash */ name = ha->keys_hash[k].elts; if (name) { for (i = 0; i < ha->keys_hash[k].nelts; i++) { if (last != name[i].len) { continue; } if (ngx_strncmp(key->data, name[i].data, last) == 0) { return NGX_BUSY; } } } else { if (ngx_array_init(&ha->keys_hash[k], ha->temp_pool, 4, sizeof(ngx_str_t)) != NGX_OK) { return NGX_ERROR; } } name = ngx_array_push(&ha->keys_hash[k]); if (name == NULL) { return NGX_ERROR; } *name = *key; hk = ngx_array_push(&ha->keys); if (hk == NULL) { return NGX_ERROR; } hk->key = *key; hk->key_hash = ngx_hash_key(key->data, last); hk->value = value; return NGX_OK; wildcard: /* wildcard hash */ k = ngx_hash_strlow(&key->data[skip], &key->data[skip], last - skip); k %= ha->hsize; if (skip == 1) { /* check conflicts in exact hash for ".example.com" */ name = ha->keys_hash[k].elts; if (name) { len = last - skip; for (i = 0; i < ha->keys_hash[k].nelts; i++) { if (len != name[i].len) { continue; } if (ngx_strncmp(&key->data[1], name[i].data, len) == 0) { return NGX_BUSY; } } } else { if (ngx_array_init(&ha->keys_hash[k], ha->temp_pool, 4, sizeof(ngx_str_t)) != NGX_OK) { return NGX_ERROR; } } name = ngx_array_push(&ha->keys_hash[k]); if (name == NULL) { return NGX_ERROR; } name->len = last - 1; name->data = ngx_pnalloc(ha->temp_pool, name->len); if (name->data == NULL) { return NGX_ERROR; } ngx_memcpy(name->data, &key->data[1], name->len); } if (skip) { /* * convert "*.example.com" to "com.example.\0" * and ".example.com" to "com.example\0" */ p = ngx_pnalloc(ha->temp_pool, last); if (p == NULL) { return NGX_ERROR; } len = 0; n = 0; for (i = last - 1; i; i--) { if (key->data[i] == '.') { ngx_memcpy(&p[n], &key->data[i + 1], len); n += len; p[n++] = '.'; len = 0; continue; } len++; } if (len) { ngx_memcpy(&p[n], &key->data[1], len); n += len; } p[n] = '\0'; hwc = &ha->dns_wc_head; keys = &ha->dns_wc_head_hash[k]; } else { /* convert "www.example.*" to "www.example\0" */ last++; p = ngx_pnalloc(ha->temp_pool, last); if (p == NULL) { return NGX_ERROR; } ngx_cpystrn(p, key->data, last); hwc = &ha->dns_wc_tail; keys = &ha->dns_wc_tail_hash[k]; } /* check conflicts in wildcard hash */ name = keys->elts; if (name) { len = last - skip; for (i = 0; i < keys->nelts; i++) { if (len != name[i].len) { continue; } if (ngx_strncmp(key->data + skip, name[i].data, len) == 0) { return NGX_BUSY; } } } else { if (ngx_array_init(keys, ha->temp_pool, 4, sizeof(ngx_str_t)) != NGX_OK) { return NGX_ERROR; } } name = ngx_array_push(keys); if (name == NULL) { return NGX_ERROR; } name->len = last - skip; name->data = ngx_pnalloc(ha->temp_pool, name->len); if (name->data == NULL) { return NGX_ERROR; } ngx_memcpy(name->data, key->data + skip, name->len); /* add to wildcard hash */ hk = ngx_array_push(hwc); if (hk == NULL) { return NGX_ERROR; } hk->key.len = last - 1; hk->key.data = p; hk->key_hash = 0; hk->value = value; return NGX_OK; }