/* * Copyright (C) Igor Sysoev */ #include #include #include #define NGX_RESOLVER_UDP_SIZE 4096 typedef struct { u_char ident_hi; u_char ident_lo; u_char flags_hi; u_char flags_lo; u_char nqs_hi; u_char nqs_lo; u_char nan_hi; u_char nan_lo; u_char nns_hi; u_char nns_lo; u_char nar_hi; u_char nar_lo; } ngx_resolver_query_t; typedef struct { u_char type_hi; u_char type_lo; u_char class_hi; u_char class_lo; } ngx_resolver_qs_t; typedef struct { u_char type_hi; u_char type_lo; u_char class_hi; u_char class_lo; u_char ttl[4]; u_char len_hi; u_char len_lo; } ngx_resolver_an_t; ngx_int_t ngx_udp_connect(ngx_udp_connection_t *uc); static void ngx_resolver_cleanup(void *data); static void ngx_resolver_cleanup_tree(ngx_resolver_t *r, ngx_rbtree_t *tree); static ngx_int_t ngx_resolve_name_locked(ngx_resolver_t *r, ngx_resolver_ctx_t *ctx); static void ngx_resolver_expire(ngx_resolver_t *r, ngx_rbtree_t *tree, ngx_queue_t *queue); static ngx_int_t ngx_resolver_send_query(ngx_resolver_t *r, ngx_resolver_node_t *rn); static ngx_int_t ngx_resolver_create_name_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx); static ngx_int_t ngx_resolver_create_addr_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx); static void ngx_resolver_resend_handler(ngx_event_t *ev); static time_t ngx_resolver_resend(ngx_resolver_t *r, ngx_rbtree_t *tree, ngx_queue_t *queue); static void ngx_resolver_read_response(ngx_event_t *rev); static void ngx_resolver_process_response(ngx_resolver_t *r, u_char *buf, size_t n); static void ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t n, ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan, ngx_uint_t ans); static void ngx_resolver_process_ptr(ngx_resolver_t *r, u_char *buf, size_t n, ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan); static ngx_resolver_node_t *ngx_resolver_lookup_name(ngx_resolver_t *r, ngx_str_t *name, uint32_t hash); static ngx_resolver_node_t *ngx_resolver_lookup_addr(ngx_resolver_t *r, in_addr_t addr); static void ngx_resolver_rbtree_insert_value(ngx_rbtree_node_t *temp, ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel); static ngx_int_t ngx_resolver_copy(ngx_resolver_t *r, ngx_str_t *name, u_char *buf, u_char *src, u_char *last); static void ngx_resolver_timeout_handler(ngx_event_t *ev); static void ngx_resolver_free_node(ngx_resolver_t *r, ngx_resolver_node_t *rn); static void *ngx_resolver_alloc(ngx_resolver_t *r, size_t size); static void *ngx_resolver_calloc(ngx_resolver_t *r, size_t size); static void ngx_resolver_free(ngx_resolver_t *r, void *p); static void ngx_resolver_free_locked(ngx_resolver_t *r, void *p); static void *ngx_resolver_dup(ngx_resolver_t *r, void *src, size_t size); /* STUB: ngx_peer_addr_t * */ ngx_resolver_t * ngx_resolver_create(ngx_conf_t *cf, ngx_peer_addr_t *addr) { ngx_resolver_t *r; ngx_pool_cleanup_t *cln; ngx_udp_connection_t *uc; cln = ngx_pool_cleanup_add(cf->pool, 0); if (cln == NULL) { return NULL; } cln->handler = ngx_resolver_cleanup; r = ngx_calloc(sizeof(ngx_resolver_t), cf->log); if (r == NULL) { return NULL; } cln->data = r; r->event = ngx_calloc(sizeof(ngx_event_t), cf->log); if (r->event == NULL) { return NULL; } ngx_rbtree_init(&r->name_rbtree, &r->name_sentinel, ngx_resolver_rbtree_insert_value); ngx_rbtree_init(&r->addr_rbtree, &r->addr_sentinel, ngx_rbtree_insert_value); ngx_queue_init(&r->name_resend_queue); ngx_queue_init(&r->addr_resend_queue); ngx_queue_init(&r->name_expire_queue); ngx_queue_init(&r->addr_expire_queue); r->event->handler = ngx_resolver_resend_handler; r->event->data = r; r->event->log = cf->cycle->new_log; r->ident = -1; r->resend_timeout = 5; r->expire = 30; r->valid = 300; r->log = cf->cycle->new_log; r->log_level = NGX_LOG_ALERT; if (addr) { uc = ngx_calloc(sizeof(ngx_udp_connection_t), cf->log); if (uc == NULL) { return NULL; } r->udp_connection = uc; uc->sockaddr = addr->sockaddr; uc->socklen = addr->socklen; uc->server = addr->name; uc->log = cf->cycle->new_log; } return r; } static void ngx_resolver_cleanup(void *data) { ngx_resolver_t *r = data; if (r) { ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, "cleanup resolver"); ngx_resolver_cleanup_tree(r, &r->name_rbtree); ngx_resolver_cleanup_tree(r, &r->addr_rbtree); if (r->event) { ngx_free(r->event); } if (r->udp_connection) { if (r->udp_connection->connection) { ngx_close_connection(r->udp_connection->connection); } ngx_free(r->udp_connection); } ngx_free(r); } } static void ngx_resolver_cleanup_tree(ngx_resolver_t *r, ngx_rbtree_t *tree) { ngx_resolver_ctx_t *ctx, *next; ngx_resolver_node_t *rn; while (tree->root != tree->sentinel) { rn = (ngx_resolver_node_t *) ngx_rbtree_min(tree->root, tree->sentinel); ngx_queue_remove(&rn->queue); for (ctx = rn->waiting; ctx; ctx = next) { next = ctx->next; if (ctx->event) { ngx_resolver_free(r, ctx->event); } ngx_resolver_free(r, ctx); } ngx_rbtree_delete(tree, &rn->node); ngx_resolver_free_node(r, rn); } } ngx_resolver_ctx_t * ngx_resolve_start(ngx_resolver_t *r, ngx_resolver_ctx_t *temp) { in_addr_t addr; ngx_resolver_ctx_t *ctx; if (temp) { addr = ngx_inet_addr(temp->name.data, temp->name.len); if (addr != INADDR_NONE) { temp->resolver = r; temp->state = NGX_OK; temp->naddrs = 1; temp->addrs = &temp->addr; temp->addr = addr; temp->quick = 1; return temp; } } if (r->udp_connection == NULL) { return NGX_NO_RESOLVER; } ctx = ngx_resolver_calloc(r, sizeof(ngx_resolver_ctx_t)); if (ctx) { ctx->resolver = r; } return ctx; } ngx_int_t ngx_resolve_name(ngx_resolver_ctx_t *ctx) { ngx_int_t rc; ngx_resolver_t *r; r = ctx->resolver; ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0, "resolve: \"%V\"", &ctx->name); if (ctx->quick) { ctx->handler(ctx); return NGX_OK; } /* lock name mutex */ rc = ngx_resolve_name_locked(r, ctx); if (rc == NGX_OK) { return NGX_OK; } /* unlock name mutex */ if (rc == NGX_AGAIN) { return NGX_OK; } /* NGX_ERROR */ if (ctx->event) { ngx_resolver_free(r, ctx->event); } ngx_resolver_free(r, ctx); return NGX_ERROR; } void ngx_resolve_name_done(ngx_resolver_ctx_t *ctx) { uint32_t hash; ngx_resolver_t *r; ngx_resolver_ctx_t *w, **p; ngx_resolver_node_t *rn; r = ctx->resolver; ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0, "resolve name done: %i", ctx->state); if (ctx->quick) { return; } if (ctx->event && ctx->event->timer_set) { ngx_del_timer(ctx->event); } /* lock name mutex */ if (ctx->state == NGX_AGAIN || ctx->state == NGX_RESOLVE_TIMEDOUT) { hash = ngx_crc32_short(ctx->name.data, ctx->name.len); rn = ngx_resolver_lookup_name(r, &ctx->name, hash); if (rn) { p = &rn->waiting; w = rn->waiting; while (w) { if (w == ctx) { *p = w->next; goto done; } p = &w->next; w = w->next; } } ngx_log_error(NGX_LOG_ALERT, r->log, 0, "could not cancel %V resolving", &ctx->name); } done: ngx_resolver_expire(r, &r->name_rbtree, &r->name_expire_queue); /* unlock name mutex */ /* lock alloc mutex */ if (ctx->event) { ngx_resolver_free_locked(r, ctx->event); } ngx_resolver_free_locked(r, ctx); /* unlock alloc mutex */ } /* NGX_RESOLVE_A only */ static ngx_int_t ngx_resolve_name_locked(ngx_resolver_t *r, ngx_resolver_ctx_t *ctx) { uint32_t hash; in_addr_t addr, *addrs; ngx_int_t rc; ngx_uint_t naddrs; ngx_resolver_ctx_t *next; ngx_resolver_node_t *rn; hash = ngx_crc32_short(ctx->name.data, ctx->name.len); rn = ngx_resolver_lookup_name(r, &ctx->name, hash); if (rn) { if (rn->valid >= ngx_time()) { ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0, "resolve cached"); ngx_queue_remove(&rn->queue); rn->expire = ngx_time() + r->expire; ngx_queue_insert_head(&r->name_expire_queue, &rn->queue); naddrs = rn->naddrs; if (naddrs) { /* NGX_RESOLVE_A answer */ if (naddrs != 1) { addr = 0; addrs = ngx_resolver_dup(r, rn->u.addrs, naddrs * sizeof(in_addr_t)); if (addrs == NULL) { return NGX_ERROR; } } else { addr = rn->u.addr; addrs = NULL; } ctx->next = rn->waiting; rn->waiting = NULL; /* unlock name mutex */ do { ctx->state = NGX_OK; ctx->naddrs = naddrs; ctx->addrs = (naddrs == 1) ? &ctx->addr : addrs; ctx->addr = addr; next = ctx->next; ctx->handler(ctx); ctx = next; } while (ctx); if (addrs) { ngx_resolver_free(r, addrs); } return NGX_OK; } /* NGX_RESOLVE_CNAME */ if (ctx->recursion++ < NGX_RESOLVER_MAX_RECURSION) { ctx->name.len = rn->cnlen; ctx->name.data = rn->u.cname; return ngx_resolve_name_locked(r, ctx); } ctx->next = rn->waiting; rn->waiting = NULL; /* unlock name mutex */ do { ctx->state = NGX_RESOLVE_NXDOMAIN; next = ctx->next; ctx->handler(ctx); ctx = next; } while (ctx); return NGX_OK; } if (rn->waiting) { ctx->next = rn->waiting; rn->waiting = ctx; return NGX_AGAIN; } ngx_queue_remove(&rn->queue); /* lock alloc mutex */ ngx_resolver_free_locked(r, rn->query); rn->query = NULL; if (rn->cnlen) { ngx_resolver_free_locked(r, rn->u.cname); } if (rn->naddrs > 1) { ngx_resolver_free_locked(r, rn->u.addrs); } /* unlock alloc mutex */ } else { rn = ngx_resolver_alloc(r, sizeof(ngx_resolver_node_t)); if (rn == NULL) { return NGX_ERROR; } rn->name = ngx_resolver_dup(r, ctx->name.data, ctx->name.len); if (rn->name == NULL) { ngx_resolver_free(r, rn); return NGX_ERROR; } rn->node.key = hash; rn->nlen = (u_short) ctx->name.len; rn->query = NULL; ngx_rbtree_insert(&r->name_rbtree, &rn->node); } rc = ngx_resolver_create_name_query(rn, ctx); if (rc == NGX_ERROR) { goto failed; } if (rc == NGX_DECLINED) { ngx_rbtree_delete(&r->name_rbtree, &rn->node); ngx_resolver_free(r, rn->query); ngx_resolver_free(r, rn->name); ngx_resolver_free(r, rn); ctx->state = NGX_RESOLVE_NXDOMAIN; ctx->handler(ctx); return NGX_OK; } if (ngx_resolver_send_query(r, rn) != NGX_OK) { goto failed; } if (ctx->event == NULL) { ctx->event = ngx_resolver_calloc(r, sizeof(ngx_event_t)); if (ctx->event == NULL) { goto failed; } ctx->event->handler = ngx_resolver_timeout_handler; ctx->event->data = ctx; ctx->event->log = r->log; ctx->ident = -1; ngx_add_timer(ctx->event, ctx->timeout); } if (ngx_queue_empty(&r->name_resend_queue)) { ngx_add_timer(r->event, (ngx_msec_t) (r->resend_timeout * 1000)); } rn->expire = ngx_time() + r->resend_timeout; ngx_queue_insert_head(&r->name_resend_queue, &rn->queue); rn->cnlen = 0; rn->naddrs = 0; rn->valid = 0; rn->waiting = ctx; ctx->state = NGX_AGAIN; return NGX_AGAIN; failed: ngx_rbtree_delete(&r->name_rbtree, &rn->node); if (rn->query) { ngx_resolver_free(r, rn->query); } ngx_resolver_free(r, rn->name); ngx_resolver_free(r, rn); return NGX_ERROR; } ngx_int_t ngx_resolve_addr(ngx_resolver_ctx_t *ctx) { ngx_resolver_t *r; ngx_resolver_node_t *rn; r = ctx->resolver; ctx->addr = ntohl(ctx->addr); /* lock addr mutex */ rn = ngx_resolver_lookup_addr(r, ctx->addr); if (rn) { if (rn->valid >= ngx_time()) { ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0, "resolve cached"); ngx_queue_remove(&rn->queue); rn->expire = ngx_time() + r->expire; ngx_queue_insert_head(&r->addr_expire_queue, &rn->queue); ctx->name.len = rn->nlen; ctx->name.data = ngx_resolver_dup(r, rn->name, rn->nlen); if (ctx->name.data == NULL) { goto failed; } /* unlock addr mutex */ ctx->state = NGX_OK; ctx->handler(ctx); ngx_resolver_free(r, ctx->name.data); return NGX_OK; } if (rn->waiting) { ctx->next = rn->waiting; rn->waiting = ctx; return NGX_AGAIN; } ngx_queue_remove(&rn->queue); ngx_resolver_free(r, rn->query); rn->query = NULL; } else { rn = ngx_resolver_alloc(r, sizeof(ngx_resolver_node_t)); if (rn == NULL) { goto failed; } rn->node.key = ctx->addr; rn->query = NULL; ngx_rbtree_insert(&r->addr_rbtree, &rn->node); } if (ngx_resolver_create_addr_query(rn, ctx) != NGX_OK) { goto failed; } if (ngx_resolver_send_query(r, rn) != NGX_OK) { goto failed; } ctx->event = ngx_resolver_calloc(r, sizeof(ngx_event_t)); if (ctx->event == NULL) { goto failed; } ctx->event->handler = ngx_resolver_timeout_handler; ctx->event->data = ctx; ctx->event->log = r->log; ctx->ident = -1; ngx_add_timer(ctx->event, ctx->timeout); if (ngx_queue_empty(&r->addr_resend_queue)) { ngx_add_timer(r->event, (ngx_msec_t) (r->resend_timeout * 1000)); } rn->expire = ngx_time() + r->resend_timeout; ngx_queue_insert_head(&r->addr_resend_queue, &rn->queue); rn->cnlen = 0; rn->naddrs = 0; rn->name = NULL; rn->nlen = 0; rn->valid = 0; rn->waiting = ctx; /* unlock addr mutex */ ctx->state = NGX_AGAIN; return NGX_OK; failed: if (rn) { ngx_rbtree_delete(&r->addr_rbtree, &rn->node); if (rn->query) { ngx_resolver_free(r, rn->query); } ngx_resolver_free(r, rn); } /* unlock addr mutex */ if (ctx->event) { ngx_resolver_free(r, ctx->event); } ngx_resolver_free(r, ctx); return NGX_ERROR; } void ngx_resolve_addr_done(ngx_resolver_ctx_t *ctx) { in_addr_t addr; ngx_resolver_t *r; ngx_resolver_ctx_t *w, **p; ngx_resolver_node_t *rn; r = ctx->resolver; ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0, "resolve addr done: %i", ctx->state); if (ctx->event && ctx->event->timer_set) { ngx_del_timer(ctx->event); } /* lock addr mutex */ if (ctx->state == NGX_AGAIN || ctx->state == NGX_RESOLVE_TIMEDOUT) { rn = ngx_resolver_lookup_addr(r, ctx->addr); if (rn) { p = &rn->waiting; w = rn->waiting; while (w) { if (w == ctx) { *p = w->next; goto done; } p = &w->next; w = w->next; } } addr = ntohl(ctx->addr); ngx_log_error(NGX_LOG_ALERT, r->log, 0, "could not cancel %ud.%ud.%ud.%ud resolving", (addr >> 24) & 0xff, (addr >> 16) & 0xff, (addr >> 8) & 0xff, addr & 0xff); } done: ngx_resolver_expire(r, &r->addr_rbtree, &r->addr_expire_queue); /* unlock addr mutex */ /* lock alloc mutex */ if (ctx->event) { ngx_resolver_free_locked(r, ctx->event); } ngx_resolver_free_locked(r, ctx); /* unlock alloc mutex */ } static void ngx_resolver_expire(ngx_resolver_t *r, ngx_rbtree_t *tree, ngx_queue_t *queue) { time_t now; ngx_uint_t i; ngx_queue_t *q; ngx_resolver_node_t *rn; ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver expire"); now = ngx_time(); for (i = 0; i < 2; i++) { if (ngx_queue_empty(queue)) { return; } q = ngx_queue_last(queue); rn = ngx_queue_data(q, ngx_resolver_node_t, queue); if (now <= rn->expire) { return; } ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver expire \"%*s\"", (size_t) rn->nlen, rn->name); ngx_queue_remove(q); ngx_rbtree_delete(tree, &rn->node); ngx_resolver_free_node(r, rn); } } static ngx_int_t ngx_resolver_send_query(ngx_resolver_t *r, ngx_resolver_node_t *rn) { ssize_t n; ngx_udp_connection_t *uc; uc = r->udp_connection; if (uc->connection == NULL) { if (ngx_udp_connect(uc) != NGX_OK) { return NGX_ERROR; } uc->connection->data = r; uc->connection->read->handler = ngx_resolver_read_response; uc->connection->read->resolver = 1; } n = ngx_send(uc->connection, rn->query, rn->qlen); if (n == -1) { return NGX_ERROR; } if ((size_t) n != (size_t) rn->qlen) { ngx_log_error(NGX_LOG_CRIT, uc->log, 0, "send() incomplete"); return NGX_ERROR; } return NGX_OK; } static void ngx_resolver_resend_handler(ngx_event_t *ev) { time_t timer, atimer, ntimer; ngx_resolver_t *r; r = ev->data; ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver resend handler"); /* lock name mutex */ ntimer = ngx_resolver_resend(r, &r->name_rbtree, &r->name_resend_queue); /* unlock name mutex */ /* lock addr mutex */ atimer = ngx_resolver_resend(r, &r->addr_rbtree, &r->addr_resend_queue); /* unlock addr mutex */ if (ntimer == 0) { timer = atimer; } else if (atimer == 0) { timer = ntimer; } else { timer = (atimer < ntimer) ? atimer : ntimer; } if (timer) { ngx_add_timer(r->event, (ngx_msec_t) (timer * 1000)); } } static time_t ngx_resolver_resend(ngx_resolver_t *r, ngx_rbtree_t *tree, ngx_queue_t *queue) { time_t now; ngx_queue_t *q; ngx_resolver_node_t *rn; now = ngx_time(); for ( ;; ) { if (ngx_queue_empty(queue)) { return 0; } q = ngx_queue_last(queue); rn = ngx_queue_data(q, ngx_resolver_node_t, queue); if (now < rn->expire) { return rn->expire - now; } ngx_log_debug3(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver resend \"%*s\" %p", (size_t) rn->nlen, rn->name, rn->waiting); ngx_queue_remove(q); if (rn->waiting) { if (ngx_resolver_send_query(r, rn) == NGX_OK) { rn->expire = now + r->resend_timeout; ngx_queue_insert_head(queue, &rn->queue); } continue; } ngx_rbtree_delete(tree, &rn->node); ngx_resolver_free_node(r, rn); } } static void ngx_resolver_read_response(ngx_event_t *rev) { ssize_t n; ngx_connection_t *c; u_char buf[NGX_RESOLVER_UDP_SIZE]; c = rev->data; do { n = ngx_udp_recv(c, buf, NGX_RESOLVER_UDP_SIZE); if (n < 0) { return; } ngx_resolver_process_response(c->data, buf, n); } while (rev->ready); } static void ngx_resolver_process_response(ngx_resolver_t *r, u_char *buf, size_t n) { char *err; size_t len; ngx_uint_t i, ident, flags, code, nqs, nan, qtype, qclass; ngx_resolver_qs_t *qs; ngx_resolver_query_t *query; if ((size_t) n < sizeof(ngx_resolver_query_t)) { goto short_response; } query = (ngx_resolver_query_t *) buf; ident = (query->ident_hi << 8) + query->ident_lo; flags = (query->flags_hi << 8) + query->flags_lo; nqs = (query->nqs_hi << 8) + query->nqs_lo; nan = (query->nan_hi << 8) + query->nan_lo; ngx_log_debug6(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver DNS response %ui fl:%04Xui %ui/%ui/%ui/%ui", ident, flags, nqs, nan, (query->nns_hi << 8) + query->nns_lo, (query->nar_hi << 8) + query->nar_lo); if (!(flags & 0x8000)) { ngx_log_error(r->log_level, r->log, 0, "invalid DNS response %ui fl:%04Xui", ident, flags); return; } code = flags & 0x7f; if (code == NGX_RESOLVE_FORMERR || code > NGX_RESOLVE_REFUSED) { ngx_log_error(r->log_level, r->log, 0, "DNS error (%ui: %s), query id:%ui", code, ngx_resolver_strerror(code), ident); return; } if (nqs != 1) { err = "invalid number of questions in DNS response"; goto done; } i = sizeof(ngx_resolver_query_t); while (i < (ngx_uint_t) n) { if (buf[i] == '\0') { goto found; } len = buf[i]; i += 1 + len; } goto short_response; found: if (i++ == 0) { err = "zero-length domain name in DNS response"; goto done; } if (i + sizeof(ngx_resolver_qs_t) + nan * (2 + sizeof(ngx_resolver_an_t)) > (ngx_uint_t) n) { goto short_response; } qs = (ngx_resolver_qs_t *) &buf[i]; qtype = (qs->type_hi << 8) + qs->type_lo; qclass = (qs->class_hi << 8) + qs->class_lo; ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver DNS response qt:%ui cl:%ui", qtype, qclass); if (qclass != 1) { ngx_log_error(r->log_level, r->log, 0, "unknown query class %ui in DNS response", qclass); return; } switch (qtype) { case NGX_RESOLVE_A: ngx_resolver_process_a(r, buf, n, ident, code, nan, i + sizeof(ngx_resolver_qs_t)); break; case NGX_RESOLVE_PTR: ngx_resolver_process_ptr(r, buf, n, ident, code, nan); break; default: ngx_log_error(r->log_level, r->log, 0, "unknown query type %ui in DNS response", qtype); return; } return; short_response: err = "short dns response"; done: ngx_log_error(r->log_level, r->log, 0, err); return; } static void ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t last, ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan, ngx_uint_t ans) { char *err; u_char *cname; size_t len; uint32_t hash; in_addr_t addr, *addrs; ngx_str_t name; ngx_uint_t qtype, qident, naddrs, a, i, n, start; ngx_resolver_an_t *an; ngx_resolver_ctx_t *ctx, *next; ngx_resolver_node_t *rn; if (ngx_resolver_copy(r, &name, buf, &buf[12], &buf[last]) != NGX_OK) { return; } ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver qs:%V", &name); hash = ngx_crc32_short(name.data, name.len); /* lock name mutex */ rn = ngx_resolver_lookup_name(r, &name, hash); if (rn == NULL || rn->query == NULL) { ngx_log_error(r->log_level, r->log, 0, "unexpected response for %V", &name); goto failed; } qident = (rn->query[0] << 8) + rn->query[1]; if (ident != qident) { ngx_log_error(r->log_level, r->log, 0, "wrong ident %ui response for %V, expect %ui", ident, &name, qident); goto failed; } if (code == 0 && nan == 0) { code = 3; /* NXDOMAIN */ } if (code) { next = rn->waiting; rn->waiting = NULL; ngx_queue_remove(&rn->queue); ngx_rbtree_delete(&r->name_rbtree, &rn->node); ngx_resolver_free_node(r, rn); /* unlock name mutex */ while (next) { ctx = next; ctx->state = code; next = ctx->next; ctx->handler(ctx); } return; } i = ans; naddrs = 0; addr = 0; addrs = NULL; cname = NULL; qtype = 0; for (a = 0; a < nan; a++) { start = i; while (i < last) { if (buf[i] & 0xc0) { i += 2; goto found; } if (buf[i] == 0) { i++; goto test_length; } i += 1 + buf[i]; } goto short_response; test_length: if (i - start < 2) { err = "invalid name in dns response"; goto invalid; } found: if (i + sizeof(ngx_resolver_an_t) >= last) { goto short_response; } an = (ngx_resolver_an_t *) &buf[i]; qtype = (an->type_hi << 8) + an->type_lo; len = (an->len_hi << 8) + an->len_lo; if (qtype == NGX_RESOLVE_A) { i += sizeof(ngx_resolver_an_t); if (i + len > last) { goto short_response; } addr = htonl((buf[i] << 24) + (buf[i + 1] << 16) + (buf[i + 2] << 8) + (buf[i + 3])); naddrs++; i += len; } else if (qtype == NGX_RESOLVE_CNAME) { cname = &buf[i] + sizeof(ngx_resolver_an_t); i += sizeof(ngx_resolver_an_t) + len; } else if (qtype == NGX_RESOLVE_DNAME) { i += sizeof(ngx_resolver_an_t) + len; } else { ngx_log_error(r->log_level, r->log, 0, "unexpected qtype %ui", qtype); } } ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver naddrs:%ui cname:%p", naddrs, cname); if (naddrs) { if (naddrs == 1) { rn->u.addr = addr; } else { addrs = ngx_resolver_alloc(r, naddrs * sizeof(in_addr_t)); if (addrs == NULL) { return; } n = 0; i = ans; for (a = 0; a < nan; a++) { for ( ;; ) { if (buf[i] & 0xc0) { i += 2; goto ok; } if (buf[i] == 0) { i++; goto ok; } i += 1 + buf[i]; } ok: an = (ngx_resolver_an_t *) &buf[i]; qtype = (an->type_hi << 8) + an->type_lo; len = (an->len_hi << 8) + an->len_lo; i += sizeof(ngx_resolver_an_t); if (qtype == NGX_RESOLVE_A) { addrs[n++] = htonl((buf[i] << 24) + (buf[i + 1] << 16) + (buf[i + 2] << 8) + (buf[i + 3])); if (n == naddrs) { break; } } i += len; } rn->u.addrs = addrs; addrs = ngx_resolver_dup(r, rn->u.addrs, naddrs * sizeof(in_addr_t)); if (addrs == NULL) { return; } } rn->naddrs = (u_short) naddrs; ngx_queue_remove(&rn->queue); rn->valid = ngx_time() + r->valid; rn->expire = ngx_time() + r->expire; ngx_queue_insert_head(&r->name_expire_queue, &rn->queue); next = rn->waiting; rn->waiting = NULL; /* unlock name mutex */ while (next) { ctx = next; ctx->state = NGX_OK; ctx->naddrs = naddrs; ctx->addrs = (naddrs == 1) ? &ctx->addr : addrs; ctx->addr = addr; next = ctx->next; ctx->handler(ctx); } if (naddrs) { ngx_resolver_free(r, addrs); } return; } else if (cname) { /* CNAME only */ if (ngx_resolver_copy(r, &name, buf, cname, &buf[last]) != NGX_OK) { return; } ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver cname:\"%V\"", &name); ngx_queue_remove(&rn->queue); rn->cnlen = (u_short) name.len; rn->u.cname = name.data; rn->valid = ngx_time() + r->valid; rn->expire = ngx_time() + r->expire; ngx_queue_insert_head(&r->name_expire_queue, &rn->queue); ctx = rn->waiting; rn->waiting = NULL; if (ctx) { ctx->name = name; (void) ngx_resolve_name_locked(r, ctx); } return; } ngx_log_error(r->log_level, r->log, 0, "no A or CNAME types in DNS responses, unknown query type: %ui", qtype); return; short_response: err = "short dns response"; invalid: /* unlock name mutex */ ngx_log_error(r->log_level, r->log, 0, err); return; failed: /* unlock name mutex */ return; } static void ngx_resolver_process_ptr(ngx_resolver_t *r, u_char *buf, size_t n, ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan) { char *err; size_t len; in_addr_t addr; ngx_int_t digit; ngx_str_t name; ngx_uint_t i, mask, qtype, qclass, qident; ngx_resolver_an_t *an; ngx_resolver_ctx_t *ctx, *next; ngx_resolver_node_t *rn; if (ngx_resolver_copy(r, NULL, buf, &buf[12], &buf[n]) != NGX_OK) { goto invalid_in_addr_arpa; } addr = 0; i = 12; for (mask = 0; mask < 32; mask += 8) { len = buf[i++]; digit = ngx_atoi(&buf[i], len); if (digit == NGX_ERROR || digit > 255) { goto invalid_in_addr_arpa; } addr += digit << mask; i += len; } if (ngx_strcmp(&buf[i], "\7in-addr\4arpa") != 0) { goto invalid_in_addr_arpa; } /* lock addr mutex */ rn = ngx_resolver_lookup_addr(r, addr); if (rn == NULL || rn->query == NULL) { ngx_log_error(r->log_level, r->log, 0, "unexpected response for %ud.%ud.%ud.%ud", (addr >> 24) & 0xff, (addr >> 16) & 0xff, (addr >> 8) & 0xff, addr & 0xff); goto failed; } qident = (rn->query[0] << 8) + rn->query[1]; if (ident != qident) { ngx_log_error(r->log_level, r->log, 0, "wrong ident %ui response for %ud.%ud.%ud.%ud, expect %ui", ident, (addr >> 24) & 0xff, (addr >> 16) & 0xff, (addr >> 8) & 0xff, addr & 0xff, qident); goto failed; } if (code == 0 && nan == 0) { code = 3; /* NXDOMAIN */ } if (code) { next = rn->waiting; rn->waiting = NULL; ngx_queue_remove(&rn->queue); ngx_rbtree_delete(&r->addr_rbtree, &rn->node); ngx_resolver_free_node(r, rn); /* unlock addr mutex */ while (next) { ctx = next; ctx->state = code; next = ctx->next; ctx->handler(ctx); } return; } i += sizeof("\7in-addr\4arpa") + sizeof(ngx_resolver_qs_t); if (i + 2 + sizeof(ngx_resolver_an_t) > (ngx_uint_t) n) { goto short_response; } /* compression pointer to "XX.XX.XX.XX.in-addr.arpa */ if (buf[i] != 0xc0 || buf[i + 1] != 0x0c) { err = "invalid in-addr.arpa name in DNS response"; goto invalid; } an = (ngx_resolver_an_t *) &buf[i + 2]; qtype = (an->type_hi << 8) + an->type_lo; qclass = (an->class_hi << 8) + an->class_lo; len = (an->len_hi << 8) + an->len_lo; ngx_log_debug3(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver qt:%ui cl:%ui len:%uz", qtype, qclass, len); i += 2 + sizeof(ngx_resolver_an_t); if (i + len > (ngx_uint_t) n) { goto short_response; } len -= 2; if (ngx_resolver_copy(r, &name, buf, &buf[i], &buf[n]) != NGX_OK) { return; } ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver an:%V", &name); if (len != (size_t) rn->nlen || ngx_strncmp(name.data, rn->name, len) != 0) { ngx_resolver_free(r, rn->name); rn->name = name.data; name.data = ngx_resolver_dup(r, rn->name, len); if (name.data == NULL) { goto failed; } } ngx_queue_remove(&rn->queue); rn->valid = ngx_time() + r->valid; rn->expire = ngx_time() + r->expire; ngx_queue_insert_head(&r->addr_expire_queue, &rn->queue); next = rn->waiting; rn->waiting = NULL; /* unlock addr mutex */ while (next) { ctx = next; ctx->state = NGX_OK; ctx->name = name; next = ctx->next; ctx->handler(ctx); } ngx_resolver_free(r, name.data); return; invalid_in_addr_arpa: ngx_log_error(r->log_level, r->log, 0, "invalid in-addr.arpa name in DNS response"); return; short_response: err = "short DNS response"; invalid: /* unlock addr mutex */ ngx_log_error(r->log_level, r->log, 0, err); return; failed: /* unlock addr mutex */ return; } static ngx_resolver_node_t * ngx_resolver_lookup_name(ngx_resolver_t *r, ngx_str_t *name, uint32_t hash) { ngx_int_t rc; size_t len; ngx_rbtree_node_t *node, *sentinel; ngx_resolver_node_t *rn; node = r->name_rbtree.root; sentinel = r->name_rbtree.sentinel; while (node != sentinel) { if (hash < node->key) { node = node->left; continue; } if (hash > node->key) { node = node->right; continue; } /* hash == node->key */ do { rn = (ngx_resolver_node_t *) node; len = (name->len > (size_t) rn->nlen) ? rn->nlen : name->len; rc = ngx_strncmp(name->data, rn->name, len); if (rc == 0) { return rn; } node = (rc < 0) ? node->left : node->right; } while (node != sentinel && hash == node->key); break; } /* not found */ return NULL; } static ngx_resolver_node_t * ngx_resolver_lookup_addr(ngx_resolver_t *r, in_addr_t addr) { ngx_rbtree_node_t *node, *sentinel; node = r->addr_rbtree.root; sentinel = r->addr_rbtree.sentinel; while (node != sentinel) { if (addr < node->key) { node = node->left; continue; } if (addr > node->key) { node = node->right; continue; } /* addr == node->key */ return (ngx_resolver_node_t *) node; } /* not found */ return NULL; } static void ngx_resolver_rbtree_insert_value(ngx_rbtree_node_t *temp, ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel) { size_t len; ngx_rbtree_node_t **p; ngx_resolver_node_t *rn, *rn_temp; for ( ;; ) { if (node->key < temp->key) { p = &temp->left; } else if (node->key > temp->key) { p = &temp->right; } else { /* node->key == temp->key */ rn = (ngx_resolver_node_t *) node; rn_temp = (ngx_resolver_node_t *) temp; len = (rn->nlen > rn_temp->nlen) ? rn_temp->nlen : rn->nlen; p = (ngx_strncmp(rn->name, rn_temp->name, len) < 0) ? &temp->left : &temp->right; } if (*p == sentinel) { break; } temp = *p; } *p = node; node->parent = temp; node->left = sentinel; node->right = sentinel; ngx_rbt_red(node); } static ngx_int_t ngx_resolver_create_name_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx) { u_char *p, *s; size_t len; ngx_uint_t ident; ngx_resolver_qs_t *qs; ngx_resolver_query_t *query; len = sizeof(ngx_resolver_query_t) + 1 + ctx->name.len + 1 + sizeof(ngx_resolver_qs_t); p = ngx_resolver_calloc(ctx->resolver, len); if (p == NULL) { return NGX_ERROR; } rn->qlen = (u_short) len; rn->query = p; query = (ngx_resolver_query_t *) p; ident = ngx_random(); ngx_log_debug2(NGX_LOG_DEBUG_CORE, ctx->resolver->log, 0, "resolve: \"%V\" %i", &ctx->name, ident & 0xffff); query->ident_hi = (u_char) ((ident >> 8) & 0xff); query->ident_lo = (u_char) (ident & 0xff); /* recursion query */ query->flags_hi = 1; query->flags_lo = 0; /* one question */ query->nqs_hi = 0; query->nqs_lo = 1; query->nan_hi = 0; query->nan_lo = 0; query->nns_hi = 0; query->nns_lo = 0; query->nar_hi = 0; query->nar_lo = 0; p += sizeof(ngx_resolver_query_t) + 1 + ctx->name.len + 1; qs = (ngx_resolver_qs_t *) p; /* query type */ qs->type_hi = 0; qs->type_lo = (u_char) ctx->type; /* IP query class */ qs->class_hi = 0; qs->class_lo = 1; /* convert "www.example.com" to "\3www\7example\3com\0" */ len = 0; p--; *p-- = '\0'; for (s = ctx->name.data + ctx->name.len - 1; s >= ctx->name.data; s--) { if (*s != '.') { *p = *s; len++; } else { if (len == 0) { return NGX_DECLINED; } *p = (u_char) len; len = 0; } p--; } *p = (u_char) len; return NGX_OK; } /* AF_INET only */ static ngx_int_t ngx_resolver_create_addr_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx) { u_char *p, *d; size_t len; ngx_int_t n; ngx_uint_t ident; ngx_resolver_query_t *query; len = sizeof(ngx_resolver_query_t) + sizeof(".255.255.255.255.in-addr.arpa.") - 1 + sizeof(ngx_resolver_qs_t); p = ngx_resolver_calloc(ctx->resolver, len); if (p == NULL) { return NGX_ERROR; } rn->query = p; query = (ngx_resolver_query_t *) p; ident = ngx_random(); query->ident_hi = (u_char) ((ident >> 8) & 0xff); query->ident_lo = (u_char) (ident & 0xff); /* recursion query */ query->flags_hi = 1; query->flags_lo = 0; /* one question */ query->nqs_hi = 0; query->nqs_lo = 1; query->nan_hi = 0; query->nan_lo = 0; query->nns_hi = 0; query->nns_lo = 0; query->nar_hi = 0; query->nar_lo = 0; p += sizeof(ngx_resolver_query_t); for (n = 0; n < 32; n += 8){ d = ngx_sprintf(&p[1], "%ud", (ctx->addr >> n) & 0xff); *p = (u_char) (d - &p[1]); p = d; } /* query type "PTR", IP query class */ ngx_memcpy(p, "\7in-addr\4arpa\0\0\14\0\1", 18); rn->qlen = (u_short) (p + sizeof("\7in-addr\4arpa") + sizeof(ngx_resolver_qs_t) - rn->query); return NGX_OK; } static ngx_int_t ngx_resolver_copy(ngx_resolver_t *r, ngx_str_t *name, u_char *buf, u_char *src, u_char *last) { char *err; u_char *p, *dst; ssize_t len; ngx_uint_t i, n; p = src; len = -1; /* * compression pointers allow to create endless loop, so we set limit; * 128 pointers should be enough to store 255-byte name */ for (i = 0; i < 128; i++) { n = *p++; if (n == 0) { goto done; } if (n & 0xc0) { n = (n & 0x3f << 8) + *p; p = &buf[n]; } else { len += 1 + n; p = &p[n]; } if (p >= last) { err = "name is out of response"; goto invalid; } } err = "compression pointers loop"; invalid: ngx_log_error(r->log_level, r->log, 0, err); return NGX_ERROR; done: if (name == NULL) { return NGX_OK; } dst = ngx_resolver_alloc(r, len); if (dst == NULL) { return NGX_ERROR; } name->data = dst; n = *src++; for ( ;; ) { if (n != 0xc0) { ngx_memcpy(dst, src, n); dst += n; src += n; n = *src++; if (n != 0) { *dst++ = '.'; } } else { n = (n & 0x3f << 8) + *src; src = &buf[n]; n = *src++; } if (n == 0) { name->len = dst - name->data; return NGX_OK; } } } static void ngx_resolver_timeout_handler(ngx_event_t *ev) { ngx_resolver_ctx_t *ctx; ctx = ev->data; ctx->state = NGX_RESOLVE_TIMEDOUT; ctx->handler(ctx); } static void ngx_resolver_free_node(ngx_resolver_t *r, ngx_resolver_node_t *rn) { /* lock alloc mutex */ if (rn->query) { ngx_resolver_free_locked(r, rn->query); } if (rn->name) { ngx_resolver_free_locked(r, rn->name); } if (rn->cnlen) { ngx_resolver_free_locked(r, rn->u.cname); } if (rn->naddrs > 1) { ngx_resolver_free_locked(r, rn->u.addrs); } ngx_resolver_free_locked(r, rn); /* unlock alloc mutex */ } static void * ngx_resolver_alloc(ngx_resolver_t *r, size_t size) { u_char *p; /* lock alloc mutex */ p = ngx_alloc(size, r->log); /* unlock alloc mutex */ return p; } static void * ngx_resolver_calloc(ngx_resolver_t *r, size_t size) { u_char *p; p = ngx_resolver_alloc(r, size); if (p) { ngx_memzero(p, size); } return p; } static void ngx_resolver_free(ngx_resolver_t *r, void *p) { /* lock alloc mutex */ ngx_free(p); /* unlock alloc mutex */ } static void ngx_resolver_free_locked(ngx_resolver_t *r, void *p) { ngx_free(p); } static void * ngx_resolver_dup(ngx_resolver_t *r, void *src, size_t size) { void *dst; dst = ngx_resolver_alloc(r, size); if (dst == NULL) { return dst; } ngx_memcpy(dst, src, size); return dst; } char * ngx_resolver_strerror(ngx_int_t err) { static char *errors[] = { "Format error", /* FORMERR */ "Server failure", /* SERVFAIL */ "Host not found", /* NXDOMAIN */ "Unimplemented", /* NOTIMP */ "Operation refused" /* REFUSED */ }; if (err > 0 && err < 6) { return errors[err - 1]; } if (err == NGX_RESOLVE_TIMEDOUT) { return "Operation timed out"; } return "Unknown error"; } ngx_int_t ngx_udp_connect(ngx_udp_connection_t *uc) { int rc; ngx_int_t event; ngx_event_t *rev, *wev; ngx_socket_t s; ngx_connection_t *c; s = ngx_socket(AF_INET, SOCK_DGRAM, 0); ngx_log_debug1(NGX_LOG_DEBUG_EVENT, uc->log, 0, "UDP socket %d", s); if (s == -1) { ngx_log_error(NGX_LOG_ALERT, uc->log, ngx_socket_errno, ngx_socket_n " failed"); return NGX_ERROR; } c = ngx_get_connection(s, uc->log); if (c == NULL) { if (ngx_close_socket(s) == -1) { ngx_log_error(NGX_LOG_ALERT, uc->log, ngx_socket_errno, ngx_close_socket_n "failed"); } return NGX_ERROR; } if (ngx_nonblocking(s) == -1) { ngx_log_error(NGX_LOG_ALERT, uc->log, ngx_socket_errno, ngx_nonblocking_n " failed"); ngx_free_connection(c); if (ngx_close_socket(s) == -1) { ngx_log_error(NGX_LOG_ALERT, uc->log, ngx_socket_errno, ngx_close_socket_n " failed"); } return NGX_ERROR; } rev = c->read; wev = c->write; rev->log = uc->log; wev->log = uc->log; uc->connection = c; c->number = ngx_atomic_fetch_add(ngx_connection_counter, 1); #if (NGX_THREADS) /* TODO: lock event when call completion handler */ rev->lock = &c->lock; wev->lock = &c->lock; rev->own_lock = &c->lock; wev->own_lock = &c->lock; #endif ngx_log_debug3(NGX_LOG_DEBUG_EVENT, uc->log, 0, "connect to %V, fd:%d #%d", &uc->server, s, c->number); rc = connect(s, uc->sockaddr, uc->socklen); /* TODO: aio, iocp */ if (rc == -1) { ngx_log_error(NGX_LOG_CRIT, uc->log, ngx_socket_errno, "connect() to %V failed", &uc->server); return NGX_ERROR; } /* UDP sockets are always ready to write */ wev->ready = 1; if (ngx_add_event) { event = (ngx_event_flags & NGX_USE_CLEAR_EVENT) ? /* kqueue, epoll */ NGX_CLEAR_EVENT: /* select, poll, /dev/poll */ NGX_LEVEL_EVENT; /* eventport event type has no meaning: oneshot only */ if (ngx_add_event(rev, NGX_READ_EVENT, event) != NGX_OK) { return NGX_ERROR; } } else { /* rtsig */ if (ngx_add_conn(c) == NGX_ERROR) { return NGX_ERROR; } } return NGX_OK; }