From 1e4c44bfe66942bb878de3e8b84f68c19cd1fbc1 Mon Sep 17 00:00:00 2001 From: Yuchen Zeng Date: Fri, 5 Aug 2016 10:54:59 -0700 Subject: [PATCH] Check in c_ares/dns_resolver.c --- .../ext/resolver/dns/c_ares/dns_resolver.c | 347 ++++++++++++++++++ 1 file changed, 347 insertions(+) create mode 100644 src/core/ext/resolver/dns/c_ares/dns_resolver.c diff --git a/src/core/ext/resolver/dns/c_ares/dns_resolver.c b/src/core/ext/resolver/dns/c_ares/dns_resolver.c new file mode 100644 index 00000000000..da328bf4f03 --- /dev/null +++ b/src/core/ext/resolver/dns/c_ares/dns_resolver.c @@ -0,0 +1,347 @@ +/* + * + * Copyright 2015, Google Inc. + * All rights reserved. + * + * 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 Google Inc. 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 + * OWNER 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. + * + */ + +#include +#include + +#include +#include +#include + +#include +#include "src/core/ext/client_config/lb_policy_registry.h" +#include "src/core/ext/client_config/resolver_registry.h" +#include "src/core/ext/resolver/dns/c_ares/grpc_ares_wrapper.h" +#include "src/core/lib/iomgr/resolve_address.h" +#include "src/core/lib/iomgr/timer.h" +#include "src/core/lib/support/backoff.h" +#include "src/core/lib/support/string.h" + +#define BACKOFF_MULTIPLIER 1.6 +#define BACKOFF_JITTER 0.2 +#define BACKOFF_MIN_SECONDS 1 +#define BACKOFF_MAX_SECONDS 120 + +typedef struct { + /** base class: must be first */ + grpc_resolver base; + /** refcount */ + gpr_refcount refs; + /** name to resolve */ + char *name; + /** default port to use */ + char *default_port; + /** subchannel factory */ + grpc_client_channel_factory *client_channel_factory; + /** load balancing policy name */ + char *lb_policy_name; + + /** mutex guarding the rest of the state */ + gpr_mu mu; + /** are we currently resolving? */ + int resolving; + /** which version of resolved_config have we published? */ + int published_version; + /** which version of resolved_config is current? */ + int resolved_version; + /** pending next completion, or NULL */ + grpc_closure *next_completion; + /** target config address for next completion */ + grpc_client_config **target_config; + /** current (fully resolved) config */ + grpc_client_config *resolved_config; + /** retry timer */ + bool have_retry_timer; + grpc_timer retry_timer; + /** retry backoff state */ + gpr_backoff backoff_state; + + /** currently resolving addresses */ + grpc_resolved_addresses *addresses; + + grpc_ares_request *request; + + grpc_polling_entity *pollent; +} dns_resolver; + +static void dns_destroy(grpc_exec_ctx *exec_ctx, grpc_resolver *r); + +static void dns_start_resolving_locked(grpc_exec_ctx *exec_ctx, + dns_resolver *r); +static void dns_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx, + dns_resolver *r); + +static void dns_shutdown(grpc_exec_ctx *exec_ctx, grpc_resolver *r); +static void dns_channel_saw_error(grpc_exec_ctx *exec_ctx, grpc_resolver *r); +static void dns_next(grpc_exec_ctx *exec_ctx, grpc_resolver *r, + grpc_polling_entity *pollent, + grpc_client_config **target_config, + grpc_closure *on_complete); + +static const grpc_resolver_vtable dns_resolver_vtable = { + dns_destroy, dns_shutdown, dns_channel_saw_error, dns_next}; + +static void dns_shutdown(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver) { + dns_resolver *r = (dns_resolver *)resolver; + gpr_mu_lock(&r->mu); + if (r->have_retry_timer) { + grpc_timer_cancel(exec_ctx, &r->retry_timer); + } + if (r->next_completion != NULL) { + *r->target_config = NULL; + grpc_exec_ctx_sched(exec_ctx, r->next_completion, + GRPC_ERROR_CREATE("Resolver Shutdown"), NULL); + r->next_completion = NULL; + } + gpr_mu_unlock(&r->mu); +} + +static void dns_channel_saw_error(grpc_exec_ctx *exec_ctx, + grpc_resolver *resolver) { + dns_resolver *r = (dns_resolver *)resolver; + gpr_mu_lock(&r->mu); + if (!r->resolving) { + gpr_backoff_reset(&r->backoff_state); + dns_start_resolving_locked(exec_ctx, r); + } + gpr_mu_unlock(&r->mu); +} + +static void dns_on_retry_timer(grpc_exec_ctx *exec_ctx, void *arg, + grpc_error *error) { + dns_resolver *r = arg; + + gpr_mu_lock(&r->mu); + r->have_retry_timer = false; + if (error == GRPC_ERROR_NONE) { + if (!r->resolving) { + dns_start_resolving_locked(exec_ctx, r); + } + } + gpr_mu_unlock(&r->mu); + + GRPC_RESOLVER_UNREF(exec_ctx, &r->base, "retry-timer"); +} + +static void dns_on_resolved(grpc_exec_ctx *exec_ctx, void *arg, + grpc_error *error) { + gpr_log(GPR_ERROR, "dns_on_resolved"); + dns_resolver *r = arg; + grpc_client_config *config = NULL; + grpc_lb_policy *lb_policy; + gpr_log(GPR_ERROR, "before mu"); + gpr_mu_lock(&r->mu); + gpr_log(GPR_ERROR, "after mu"); + GPR_ASSERT(r->resolving); + r->resolving = 0; + grpc_resolved_addresses *addresses = r->addresses; + if (addresses != NULL) { + gpr_log(GPR_ERROR, "addresses != NULL"); + grpc_lb_policy_args lb_policy_args; + config = grpc_client_config_create(); + memset(&lb_policy_args, 0, sizeof(lb_policy_args)); + lb_policy_args.addresses = addresses; + lb_policy_args.client_channel_factory = r->client_channel_factory; + lb_policy = + grpc_lb_policy_create(exec_ctx, r->lb_policy_name, &lb_policy_args); + if (lb_policy != NULL) { + grpc_client_config_set_lb_policy(config, lb_policy); + GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "construction"); + } + grpc_resolved_addresses_destroy(addresses); + } else { + gpr_log(GPR_ERROR, "addresses == NULL"); + gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC); + gpr_timespec next_try = gpr_backoff_step(&r->backoff_state, now); + gpr_timespec timeout = gpr_time_sub(next_try, now); + const char *msg = grpc_error_string(error); + gpr_log(GPR_DEBUG, "dns resolution failed: %s", msg); + grpc_error_free_string(msg); + GPR_ASSERT(!r->have_retry_timer); + r->have_retry_timer = true; + GRPC_RESOLVER_REF(&r->base, "retry-timer"); + if (gpr_time_cmp(timeout, gpr_time_0(timeout.clock_type)) <= 0) { + gpr_log(GPR_DEBUG, "retrying in %" PRId64 ".%09d seconds", timeout.tv_sec, + timeout.tv_nsec); + } else { + gpr_log(GPR_DEBUG, "retrying immediately"); + } + grpc_timer_init(exec_ctx, &r->retry_timer, next_try, dns_on_retry_timer, r, + now); + } + if (r->resolved_config) { + grpc_client_config_unref(exec_ctx, r->resolved_config); + } + r->resolved_config = config; + r->resolved_version++; + dns_maybe_finish_next_locked(exec_ctx, r); + gpr_mu_unlock(&r->mu); + gpr_log(GPR_ERROR, "mu_unlock"); + GRPC_RESOLVER_UNREF(exec_ctx, &r->base, "dns-resolving"); + gpr_log(GPR_ERROR, "after GRPC_RESOLVER_UNREF"); +} + +static void dns_next(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver, + grpc_polling_entity *pollent, + grpc_client_config **target_config, + grpc_closure *on_complete) { + dns_resolver *r = (dns_resolver *)resolver; + gpr_mu_lock(&r->mu); + GPR_ASSERT(!r->next_completion); + r->next_completion = on_complete; + r->target_config = target_config; + if (r->resolved_version == 0 && !r->resolving) { + gpr_backoff_reset(&r->backoff_state); + gpr_log(GPR_ERROR, "dns_start_resolving_locked"); + GRPC_RESOLVER_REF(&r->base, "dns-resolving"); + GPR_ASSERT(!r->resolving); + if (pollent) { + r->pollent = pollent; + grpc_polling_entity_add_to_pollset_set(exec_ctx, pollent, + r->base.pollset_set); + } + r->resolving = 1; + r->addresses = NULL; + r->request = grpc_resolve_address_ares( + exec_ctx, r->name, r->default_port, r->base.pollset_set, + grpc_closure_create(dns_on_resolved, r), &r->addresses); + } else { + dns_maybe_finish_next_locked(exec_ctx, r); + } + gpr_mu_unlock(&r->mu); +} + +static void dns_start_resolving_locked(grpc_exec_ctx *exec_ctx, + dns_resolver *r) { + gpr_log(GPR_ERROR, "dns_start_resolving_locked"); + GRPC_RESOLVER_REF(&r->base, "dns-resolving"); + GPR_ASSERT(!r->resolving); + r->resolving = 1; + r->addresses = NULL; + r->request = grpc_resolve_address_ares( + exec_ctx, r->name, r->default_port, r->base.pollset_set, + grpc_closure_create(dns_on_resolved, r), &r->addresses); + // grpc_resolve_address(exec_ctx, r->name, r->default_port, + // grpc_closure_create(dns_on_resolved, r), &r->addresses); +} + +static void dns_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx, + dns_resolver *r) { + if (r->next_completion != NULL && + r->resolved_version != r->published_version) { + *r->target_config = r->resolved_config; + if (r->resolved_config) { + grpc_client_config_ref(r->resolved_config); + } + grpc_exec_ctx_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE, NULL); + r->next_completion = NULL; + r->published_version = r->resolved_version; + } +} + +static void dns_destroy(grpc_exec_ctx *exec_ctx, grpc_resolver *gr) { + dns_resolver *r = (dns_resolver *)gr; + gpr_mu_destroy(&r->mu); + if (r->resolved_config) { + grpc_client_config_unref(exec_ctx, r->resolved_config); + } + grpc_client_channel_factory_unref(exec_ctx, r->client_channel_factory); + gpr_free(r->name); + gpr_free(r->default_port); + gpr_free(r->lb_policy_name); + gpr_free(r); +} + +static grpc_resolver *dns_create(grpc_resolver_args *args, + const char *default_port, + const char *lb_policy_name) { + dns_resolver *r; + const char *path = args->uri->path; + + if (0 != strcmp(args->uri->authority, "")) { + gpr_log(GPR_ERROR, "authority based dns uri's not supported"); + return NULL; + } + + if (path[0] == '/') ++path; + + r = gpr_malloc(sizeof(dns_resolver)); + memset(r, 0, sizeof(*r)); + gpr_ref_init(&r->refs, 1); + gpr_mu_init(&r->mu); + grpc_resolver_init(&r->base, &dns_resolver_vtable); + r->name = gpr_strdup(path); + r->default_port = gpr_strdup(default_port); + r->client_channel_factory = args->client_channel_factory; + gpr_backoff_init(&r->backoff_state, BACKOFF_MULTIPLIER, BACKOFF_JITTER, + BACKOFF_MIN_SECONDS * 1000, BACKOFF_MAX_SECONDS * 1000); + grpc_client_channel_factory_ref(r->client_channel_factory); + r->lb_policy_name = gpr_strdup(lb_policy_name); + grpc_ares_init(); + return &r->base; +} + +/* + * FACTORY + */ + +static void dns_factory_ref(grpc_resolver_factory *factory) {} + +static void dns_factory_unref(grpc_resolver_factory *factory) {} + +static grpc_resolver *dns_factory_create_resolver( + grpc_resolver_factory *factory, grpc_resolver_args *args) { + return dns_create(args, "https", "pick_first"); +} + +static char *dns_factory_get_default_host_name(grpc_resolver_factory *factory, + grpc_uri *uri) { + const char *path = uri->path; + if (path[0] == '/') ++path; + return gpr_strdup(path); +} + +static const grpc_resolver_factory_vtable dns_factory_vtable = { + dns_factory_ref, dns_factory_unref, dns_factory_create_resolver, + dns_factory_get_default_host_name, "dns"}; +static grpc_resolver_factory dns_resolver_factory = {&dns_factory_vtable}; + +static grpc_resolver_factory *dns_resolver_factory_create() { + return &dns_resolver_factory; +} + +void grpc_resolver_dns_ares_init(void) { + grpc_register_resolver_type(dns_resolver_factory_create()); +} + +void grpc_resolver_dns_ares_shutdown(void) {}