| /* |
| * |
| * 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 "src/core/client_config/resolvers/dns_resolver.h" |
| |
| #include <string.h> |
| |
| #include <grpc/support/alloc.h> |
| #include <grpc/support/host_port.h> |
| #include <grpc/support/string_util.h> |
| |
| #include "src/core/client_config/lb_policies/pick_first.h" |
| #include "src/core/client_config/subchannel_factory_decorators/add_channel_arg.h" |
| #include "src/core/iomgr/resolve_address.h" |
| #include "src/core/support/string.h" |
| |
| 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_subchannel_factory *subchannel_factory; |
| /** load balancing policy factory */ |
| grpc_lb_policy *(*lb_policy_factory)(grpc_subchannel **subchannels, |
| size_t num_subchannels); |
| |
| /** 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_iomgr_closure *next_completion; |
| /** target config address for next completion */ |
| grpc_client_config **target_config; |
| /** current (fully resolved) config */ |
| grpc_client_config *resolved_config; |
| } dns_resolver; |
| |
| static void dns_destroy(grpc_resolver *r); |
| |
| static void dns_start_resolving_locked(dns_resolver *r); |
| static void dns_maybe_finish_next_locked(dns_resolver *r); |
| |
| static void dns_shutdown(grpc_resolver *r); |
| static void dns_channel_saw_error(grpc_resolver *r, |
| struct sockaddr *failing_address, |
| int failing_address_len); |
| static void dns_next(grpc_resolver *r, grpc_client_config **target_config, |
| grpc_iomgr_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_resolver *resolver) { |
| dns_resolver *r = (dns_resolver *)resolver; |
| gpr_mu_lock(&r->mu); |
| if (r->next_completion != NULL) { |
| *r->target_config = NULL; |
| grpc_iomgr_add_callback(r->next_completion); |
| r->next_completion = NULL; |
| } |
| gpr_mu_unlock(&r->mu); |
| } |
| |
| static void dns_channel_saw_error(grpc_resolver *resolver, struct sockaddr *sa, |
| int len) { |
| dns_resolver *r = (dns_resolver *)resolver; |
| gpr_mu_lock(&r->mu); |
| if (!r->resolving) { |
| dns_start_resolving_locked(r); |
| } |
| gpr_mu_unlock(&r->mu); |
| } |
| |
| static void dns_next(grpc_resolver *resolver, |
| grpc_client_config **target_config, |
| grpc_iomgr_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) { |
| dns_start_resolving_locked(r); |
| } else { |
| dns_maybe_finish_next_locked(r); |
| } |
| gpr_mu_unlock(&r->mu); |
| } |
| |
| static void dns_on_resolved(void *arg, grpc_resolved_addresses *addresses) { |
| dns_resolver *r = arg; |
| grpc_client_config *config = NULL; |
| grpc_subchannel **subchannels; |
| grpc_subchannel_args args; |
| grpc_lb_policy *lb_policy; |
| size_t i; |
| if (addresses) { |
| config = grpc_client_config_create(); |
| subchannels = gpr_malloc(sizeof(grpc_subchannel *) * addresses->naddrs); |
| for (i = 0; i < addresses->naddrs; i++) { |
| memset(&args, 0, sizeof(args)); |
| args.addr = (struct sockaddr *)(addresses->addrs[i].addr); |
| args.addr_len = addresses->addrs[i].len; |
| subchannels[i] = grpc_subchannel_factory_create_subchannel( |
| r->subchannel_factory, &args); |
| } |
| lb_policy = r->lb_policy_factory(subchannels, addresses->naddrs); |
| grpc_client_config_set_lb_policy(config, lb_policy); |
| GRPC_LB_POLICY_UNREF(lb_policy, "construction"); |
| grpc_resolved_addresses_destroy(addresses); |
| gpr_free(subchannels); |
| } |
| gpr_mu_lock(&r->mu); |
| GPR_ASSERT(r->resolving); |
| r->resolving = 0; |
| if (r->resolved_config) { |
| grpc_client_config_unref(r->resolved_config); |
| } |
| r->resolved_config = config; |
| r->resolved_version++; |
| dns_maybe_finish_next_locked(r); |
| gpr_mu_unlock(&r->mu); |
| |
| GRPC_RESOLVER_UNREF(&r->base, "dns-resolving"); |
| } |
| |
| static void dns_start_resolving_locked(dns_resolver *r) { |
| GRPC_RESOLVER_REF(&r->base, "dns-resolving"); |
| GPR_ASSERT(!r->resolving); |
| r->resolving = 1; |
| grpc_resolve_address(r->name, r->default_port, dns_on_resolved, r); |
| } |
| |
| static void dns_maybe_finish_next_locked(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_iomgr_add_callback(r->next_completion); |
| r->next_completion = NULL; |
| r->published_version = r->resolved_version; |
| } |
| } |
| |
| static void dns_destroy(grpc_resolver *gr) { |
| dns_resolver *r = (dns_resolver *)gr; |
| gpr_mu_destroy(&r->mu); |
| if (r->resolved_config) { |
| grpc_client_config_unref(r->resolved_config); |
| } |
| grpc_subchannel_factory_unref(r->subchannel_factory); |
| gpr_free(r->name); |
| gpr_free(r->default_port); |
| gpr_free(r); |
| } |
| |
| static grpc_resolver *dns_create( |
| grpc_uri *uri, const char *default_port, |
| grpc_lb_policy *(*lb_policy_factory)(grpc_subchannel **subchannels, |
| size_t num_subchannels), |
| grpc_subchannel_factory *subchannel_factory) { |
| dns_resolver *r; |
| const char *path = uri->path; |
| |
| if (0 != strcmp(uri->authority, "")) { |
| gpr_log(GPR_ERROR, "authority based 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->subchannel_factory = subchannel_factory; |
| grpc_subchannel_factory_ref(subchannel_factory); |
| r->lb_policy_factory = lb_policy_factory; |
| 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_uri *uri, |
| grpc_subchannel_factory *subchannel_factory) { |
| return dns_create(uri, "https", grpc_create_pick_first_lb_policy, |
| subchannel_factory); |
| } |
| |
| 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}; |
| |
| grpc_resolver_factory *grpc_dns_resolver_factory_create() { |
| return &dns_resolver_factory; |
| } |