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/*
*
* Copyright 2016 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#include <grpc/support/port_platform.h>
#include "src/core/ext/filters/client_channel/http_proxy.h"
#include <stdbool.h>
#include <string.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/string_util.h>
#include "src/core/ext/filters/client_channel/http_connect_handshaker.h"
#include "src/core/ext/filters/client_channel/proxy_mapper_registry.h"
#include "src/core/lib/channel/channel_args.h"
#include "src/core/lib/gpr/env.h"
#include "src/core/lib/gpr/host_port.h"
#include "src/core/lib/gpr/string.h"
#include "src/core/lib/slice/b64.h"
#include "src/core/lib/uri/uri_parser.h"
/**
* Parses the 'https_proxy' env var (fallback on 'http_proxy') and returns the
* proxy hostname to resolve or nullptr on error. Also sets 'user_cred' to user
* credentials if present in the 'http_proxy' env var, otherwise leaves it
* unchanged. It is caller's responsibility to gpr_free user_cred.
*/
static char* get_http_proxy_server(char** user_cred) {
GPR_ASSERT(user_cred != nullptr);
char* proxy_name = nullptr;
char** authority_strs = nullptr;
size_t authority_nstrs;
/* Prefer using 'https_proxy'. Fallback on 'http_proxy' if it is not set. The
* fallback behavior can be removed if there's a demand for it.
*/
char* uri_str = gpr_getenv("https_proxy");
if (uri_str == nullptr) uri_str = gpr_getenv("http_proxy");
if (uri_str == nullptr) return nullptr;
grpc_uri* uri = grpc_uri_parse(uri_str, false /* suppress_errors */);
if (uri == nullptr || uri->authority == nullptr) {
gpr_log(GPR_ERROR, "cannot parse value of 'http_proxy' env var");
goto done;
}
if (strcmp(uri->scheme, "http") != 0) {
gpr_log(GPR_ERROR, "'%s' scheme not supported in proxy URI", uri->scheme);
goto done;
}
/* Split on '@' to separate user credentials from host */
gpr_string_split(uri->authority, "@", &authority_strs, &authority_nstrs);
GPR_ASSERT(authority_nstrs != 0); /* should have at least 1 string */
if (authority_nstrs == 1) {
/* User cred not present in authority */
proxy_name = authority_strs[0];
} else if (authority_nstrs == 2) {
/* User cred found */
*user_cred = authority_strs[0];
proxy_name = authority_strs[1];
gpr_log(GPR_DEBUG, "userinfo found in proxy URI");
} else {
/* Bad authority */
for (size_t i = 0; i < authority_nstrs; i++) {
gpr_free(authority_strs[i]);
}
proxy_name = nullptr;
}
gpr_free(authority_strs);
done:
gpr_free(uri_str);
grpc_uri_destroy(uri);
return proxy_name;
}
/**
* Checks the value of GRPC_ARG_ENABLE_HTTP_PROXY to determine if http_proxy
* should be used.
*/
bool http_proxy_enabled(const grpc_channel_args* args) {
const grpc_arg* arg =
grpc_channel_args_find(args, GRPC_ARG_ENABLE_HTTP_PROXY);
return grpc_channel_arg_get_bool(arg, true);
}
static bool proxy_mapper_map_name(grpc_proxy_mapper* mapper,
const char* server_uri,
const grpc_channel_args* args,
char** name_to_resolve,
grpc_channel_args** new_args) {
if (!http_proxy_enabled(args)) {
return false;
}
char* user_cred = nullptr;
*name_to_resolve = get_http_proxy_server(&user_cred);
if (*name_to_resolve == nullptr) return false;
char* no_proxy_str = nullptr;
grpc_uri* uri = grpc_uri_parse(server_uri, false /* suppress_errors */);
if (uri == nullptr || uri->path[0] == '\0') {
gpr_log(GPR_ERROR,
"'http_proxy' environment variable set, but cannot "
"parse server URI '%s' -- not using proxy",
server_uri);
goto no_use_proxy;
}
if (strcmp(uri->scheme, "unix") == 0) {
gpr_log(GPR_INFO, "not using proxy for Unix domain socket '%s'",
server_uri);
goto no_use_proxy;
}
no_proxy_str = gpr_getenv("no_proxy");
if (no_proxy_str != nullptr) {
static const char* NO_PROXY_SEPARATOR = ",";
bool use_proxy = true;
char* server_host;
char* server_port;
if (!gpr_split_host_port(uri->path[0] == '/' ? uri->path + 1 : uri->path,
&server_host, &server_port)) {
gpr_log(GPR_INFO,
"unable to split host and port, not checking no_proxy list for "
"host '%s'",
server_uri);
gpr_free(no_proxy_str);
} else {
size_t uri_len = strlen(server_host);
char** no_proxy_hosts;
size_t num_no_proxy_hosts;
gpr_string_split(no_proxy_str, NO_PROXY_SEPARATOR, &no_proxy_hosts,
&num_no_proxy_hosts);
for (size_t i = 0; i < num_no_proxy_hosts; i++) {
char* no_proxy_entry = no_proxy_hosts[i];
size_t no_proxy_len = strlen(no_proxy_entry);
if (no_proxy_len <= uri_len &&
gpr_stricmp(no_proxy_entry, &server_host[uri_len - no_proxy_len]) ==
0) {
gpr_log(GPR_INFO, "not using proxy for host in no_proxy list '%s'",
server_uri);
use_proxy = false;
break;
}
}
for (size_t i = 0; i < num_no_proxy_hosts; i++) {
gpr_free(no_proxy_hosts[i]);
}
gpr_free(no_proxy_hosts);
gpr_free(server_host);
gpr_free(server_port);
gpr_free(no_proxy_str);
if (!use_proxy) goto no_use_proxy;
}
}
grpc_arg args_to_add[2];
args_to_add[0] = grpc_channel_arg_string_create(
(char*)GRPC_ARG_HTTP_CONNECT_SERVER,
uri->path[0] == '/' ? uri->path + 1 : uri->path);
if (user_cred != nullptr) {
/* Use base64 encoding for user credentials as stated in RFC 7617 */
char* encoded_user_cred =
grpc_base64_encode(user_cred, strlen(user_cred), 0, 0);
char* header;
gpr_asprintf(&header, "Proxy-Authorization:Basic %s", encoded_user_cred);
gpr_free(encoded_user_cred);
args_to_add[1] = grpc_channel_arg_string_create(
(char*)GRPC_ARG_HTTP_CONNECT_HEADERS, header);
*new_args = grpc_channel_args_copy_and_add(args, args_to_add, 2);
gpr_free(header);
} else {
*new_args = grpc_channel_args_copy_and_add(args, args_to_add, 1);
}
grpc_uri_destroy(uri);
gpr_free(user_cred);
return true;
no_use_proxy:
if (uri != nullptr) grpc_uri_destroy(uri);
gpr_free(*name_to_resolve);
*name_to_resolve = nullptr;
gpr_free(user_cred);
return false;
}
static bool proxy_mapper_map_address(grpc_proxy_mapper* mapper,
const grpc_resolved_address* address,
const grpc_channel_args* args,
grpc_resolved_address** new_address,
grpc_channel_args** new_args) {
return false;
}
static void proxy_mapper_destroy(grpc_proxy_mapper* mapper) {}
static const grpc_proxy_mapper_vtable proxy_mapper_vtable = {
proxy_mapper_map_name, proxy_mapper_map_address, proxy_mapper_destroy};
static grpc_proxy_mapper proxy_mapper = {&proxy_mapper_vtable};
void grpc_register_http_proxy_mapper() {
grpc_proxy_mapper_register(true /* at_start */, &proxy_mapper);
}
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