| /* |
| * |
| * 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 <string.h> |
| |
| #include <grpc/support/alloc.h> |
| #include <grpc/support/host_port.h> |
| #include <grpc/support/string_util.h> |
| |
| #include "src/core/ext/client_config/lb_policy_registry.h" |
| #include "src/core/ext/client_config/resolver_registry.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; |
| } 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_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_next(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver, |
| 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); |
| dns_start_resolving_locked(exec_ctx, r); |
| } else { |
| dns_maybe_finish_next_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) { |
| dns_resolver *r = arg; |
| grpc_client_config *config = NULL; |
| grpc_lb_policy *lb_policy; |
| gpr_mu_lock(&r->mu); |
| GPR_ASSERT(r->resolving); |
| r->resolving = 0; |
| grpc_resolved_addresses *addresses = r->addresses; |
| if (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_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); |
| |
| GRPC_RESOLVER_UNREF(exec_ctx, &r->base, "dns-resolving"); |
| } |
| |
| static void dns_start_resolving_locked(grpc_exec_ctx *exec_ctx, |
| dns_resolver *r) { |
| GRPC_RESOLVER_REF(&r->base, "dns-resolving"); |
| GPR_ASSERT(!r->resolving); |
| r->resolving = 1; |
| r->addresses = NULL; |
| 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); |
| 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_native_init(void) { |
| grpc_register_resolver_type(dns_resolver_factory_create()); |
| } |
| |
| void grpc_resolver_dns_native_shutdown(void) {} |