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356 | // Copyright (C) 2015-2024 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
#include <config.h>
#include <dhcp/libdhcp++.h>
#include <dhcpsrv/cfgmgr.h>
#include <dhcpsrv/client_class_def.h>
#include <dhcpsrv/parsers/dhcp_parsers.h>
#include <dhcpsrv/parsers/client_class_def_parser.h>
#include <dhcpsrv/parsers/simple_parser4.h>
#include <dhcpsrv/parsers/simple_parser6.h>
#include <eval/eval_context.h>
#include <asiolink/io_address.h>
#include <asiolink/io_error.h>
#include <algorithm><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <sstream><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
using namespace isc::data;
using namespace isc::asiolink;
using namespace isc::util;
using namespace std;
/// @file client_class_def_parser.cc
///
/// @brief Method implementations for client class definition parsing
namespace isc {
namespace dhcp {
// ********************** ExpressionParser ****************************
void
ExpressionParser::parse(ExpressionPtr& expression,
ConstElementPtr expression_cfg,
uint16_t family,
EvalContext::CheckDefined check_defined,
EvalContext::ParserType parser_type) {
if (expression_cfg->getType() != Element::string) {
isc_throw(DhcpConfigError, "expression ["
<< expression_cfg->str() << "] must be a string, at ("
<< expression_cfg->getPosition() << ")");
}
// Get the expression's text via getValue() as the text returned
// by str() enclosed in quotes.
std::string value;
expression_cfg->getValue(value);
if (parser_type == EvalContext::PARSER_STRING && value.empty()) {
isc_throw(DhcpConfigError, "expression can not be empty at ("
<< expression_cfg->getPosition() << ")");
}
try {
EvalContext eval_ctx(family == AF_INET ? Option::V4 : Option::V6,
check_defined);
eval_ctx.parseString(value, parser_type);
expression.reset(new Expression());
*expression = eval_ctx.expression;
} catch (const std::exception& ex) {
// Append position if there is a failure.
isc_throw(DhcpConfigError,
"expression: [" << value
<< "] error: " << ex.what() << " at ("
<< expression_cfg->getPosition() << ")");
}
}
// ********************** ClientClassDefParser ****************************
void
ClientClassDefParser::parse(ClientClassDictionaryPtr& class_dictionary,
ConstElementPtr class_def_cfg,
uint16_t family,
bool append_error_position,
bool check_dependencies) {
// name is now mandatory, so let's deal with it first.
std::string name = getString(class_def_cfg, "name");
if (name.empty()) {
isc_throw(DhcpConfigError,
"not empty parameter 'name' is required "
<< getPosition("name", class_def_cfg) << ")");
}
EvalContext::ParserType parser_type = EvalContext::PARSER_BOOL;
// Let's try to parse the template-test expression
bool is_template = false;
// Parse matching expression
ExpressionPtr match_expr;
ConstElementPtr test_cfg = class_def_cfg->get("test");
ConstElementPtr template_test_cfg = class_def_cfg->get("template-test");
if (test_cfg && template_test_cfg) {
isc_throw(DhcpConfigError, "can not use both 'test' and 'template-test' ("
<< test_cfg->getPosition() << ") and ("
<< template_test_cfg->getPosition() << ")");
}
std::string test;
bool depend_on_known = false;
EvalContext::CheckDefined check_defined = EvalContext::acceptAll;
if (template_test_cfg) {
test_cfg = template_test_cfg;
parser_type = EvalContext::PARSER_STRING;
is_template = true;
} else {
check_defined = [&class_dictionary, &depend_on_known, check_dependencies](const ClientClass& cclass) {
return (!check_dependencies || isClientClassDefined(class_dictionary, depend_on_known, cclass));
};
}
if (test_cfg) {
ExpressionParser parser;
parser.parse(match_expr, test_cfg, family, check_defined, parser_type);
test = test_cfg->stringValue();
}
// Parse option def
CfgOptionDefPtr defs(new CfgOptionDef());
ConstElementPtr option_defs = class_def_cfg->get("option-def");
if (option_defs) {
// Apply defaults
SimpleParser::setListDefaults(option_defs,
family == AF_INET ?
SimpleParser4::OPTION4_DEF_DEFAULTS :
SimpleParser6::OPTION6_DEF_DEFAULTS);
OptionDefParser parser(family);
for (auto const& option_def : option_defs->listValue()) {
OptionDefinitionPtr def = parser.parse(option_def);
// Verify if the definition is for an option which is in a deferred
// processing list.
if (!LibDHCP::shouldDeferOptionUnpack(def->getOptionSpaceName(),
def->getCode())) {
isc_throw(DhcpConfigError,
"Not allowed option definition for code '"
<< def->getCode() << "' in space '"
<< def->getOptionSpaceName() << "' at ("
<< option_def->getPosition() << ")");
}
try {
defs->add(def);
} catch (const std::exception& ex) {
// Sanity check: it should never happen
isc_throw(DhcpConfigError, ex.what() << " ("
<< option_def->getPosition() << ")");
}
}
}
// Parse option data
CfgOptionPtr options(new CfgOption());
ConstElementPtr option_data = class_def_cfg->get("option-data");
if (option_data) {
auto opts_parser = createOptionDataListParser(family, defs);
opts_parser->parse(options, option_data);
}
// Parse user context
ConstElementPtr user_context = class_def_cfg->get("user-context");
if (user_context) {
if (user_context->getType() != Element::map) {
isc_throw(isc::dhcp::DhcpConfigError, "User context has to be a map ("
<< user_context->getPosition() << ")");
}
}
// Let's try to parse the only-if-required flag
bool required = false;
if (class_def_cfg->contains("only-if-required")) {
required = getBoolean(class_def_cfg, "only-if-required");
}
// Let's try to parse the next-server field
IOAddress next_server("0.0.0.0");
if (class_def_cfg->contains("next-server")) {
std::string next_server_txt = getString(class_def_cfg, "next-server");
try {
next_server = IOAddress(next_server_txt);
} catch (const IOError& ex) {
isc_throw(DhcpConfigError,
"Invalid next-server value specified: '"
<< next_server_txt << "' ("
<< getPosition("next-server", class_def_cfg) << ")");
}
if (next_server.getFamily() != AF_INET) {
isc_throw(DhcpConfigError, "Invalid next-server value: '"
<< next_server_txt << "', must be IPv4 address ("
<< getPosition("next-server", class_def_cfg) << ")");
}
if (next_server.isV4Bcast()) {
isc_throw(DhcpConfigError, "Invalid next-server value: '"
<< next_server_txt << "', must not be a broadcast ("
<< getPosition("next-server", class_def_cfg) << ")");
}
}
// Let's try to parse server-hostname
std::string sname;
if (class_def_cfg->contains("server-hostname")) {
sname = getString(class_def_cfg, "server-hostname");
if (sname.length() >= Pkt4::MAX_SNAME_LEN) {
isc_throw(DhcpConfigError, "server-hostname must be at most "
<< Pkt4::MAX_SNAME_LEN - 1 << " bytes long, it is "
<< sname.length() << " ("
<< getPosition("server-hostname", class_def_cfg) << ")");
}
}
// Let's try to parse boot-file-name
std::string filename;
if (class_def_cfg->contains("boot-file-name")) {
filename = getString(class_def_cfg, "boot-file-name");
if (filename.length() > Pkt4::MAX_FILE_LEN) {
isc_throw(DhcpConfigError, "boot-file-name must be at most "
<< Pkt4::MAX_FILE_LEN - 1 << " bytes long, it is "
<< filename.length() << " ("
<< getPosition("boot-file-name", class_def_cfg) << ")");
}
}
Optional<uint32_t> offer_lft;
if (class_def_cfg->contains("offer-lifetime")) {
auto value = getInteger(class_def_cfg, "offer-lifetime");
if (value < 0) {
isc_throw(DhcpConfigError, "the value of offer-lifetime '"
<< value << "' must be a positive number ("
<< getPosition("offer-lifetime", class_def_cfg) << ")");
}
offer_lft = value;
}
// Parse valid lifetime triplet.
Triplet<uint32_t> valid_lft = parseIntTriplet(class_def_cfg, "valid-lifetime");
Triplet<uint32_t> preferred_lft;
if (family != AF_INET) {
// Parse preferred lifetime triplet.
preferred_lft = parseIntTriplet(class_def_cfg, "preferred-lifetime");
}
// Sanity checks on built-in classes
for (auto const& bn : builtinNames) {
if (name == bn) {
if (required) {
isc_throw(DhcpConfigError, "built-in class '" << name
<< "' only-if-required flag must be false");
}
if (!test.empty()) {
isc_throw(DhcpConfigError, "built-in class '" << name
<< "' test expression must be empty");
}
}
}
// Sanity checks on DROP
if (name == "DROP") {
if (required) {
isc_throw(DhcpConfigError, "special class '" << name
<< "' only-if-required flag must be false");
}
// depend_on_known is now allowed
}
// Add the client class definition
try {
class_dictionary->addClass(name, match_expr, test, required,
depend_on_known, options, defs,
user_context, next_server, sname, filename,
valid_lft, preferred_lft, is_template, offer_lft);
} catch (const std::exception& ex) {
std::ostringstream s;
s << "Can't add class: " << ex.what();
// Append position of the error in JSON string if required.
if (append_error_position) {
s << " (" << class_def_cfg->getPosition() << ")";
}
isc_throw(DhcpConfigError, s.str());
}
}
void
ClientClassDefParser::checkParametersSupported(const ConstElementPtr& class_def_cfg,
const uint16_t family) {
// Make sure that the client class definition is stored in a map.
if (!class_def_cfg || (class_def_cfg->getType() != Element::map)) {
isc_throw(DhcpConfigError, "client class definition is not a map");
}
// Common v4 and v6 parameters supported for the client class.
static std::set<std::string> supported_params = { "name",
"test",
"option-data",
"user-context",
"only-if-required",
"valid-lifetime",
"min-valid-lifetime",
"max-valid-lifetime",
"template-test"};
// The v4 client class supports additional parameters.
static std::set<std::string> supported_params_v4 = { "option-def",
"next-server",
"server-hostname",
"boot-file-name" };
// The v6 client class supports additional parameters.
static std::set<std::string> supported_params_v6 = { "preferred-lifetime",
"min-preferred-lifetime",
"max-preferred-lifetime" };
// Iterate over the specified parameters and check if they are all supported.
for (auto const& name_value_pair : class_def_cfg->mapValue()) {
if ((supported_params.count(name_value_pair.first) > 0) ||
((family == AF_INET) && (supported_params_v4.count(name_value_pair.first) > 0)) ||
((family != AF_INET) && (supported_params_v6.count(name_value_pair.first) > 0))) {
continue;
} else {
isc_throw(DhcpConfigError, "unsupported client class parameter '"
<< name_value_pair.first << "'");
}
}
}
boost::shared_ptr<OptionDataListParser>
ClientClassDefParser::createOptionDataListParser(const uint16_t address_family,
CfgOptionDefPtr cfg_option_def) const {
auto parser = boost::make_shared<OptionDataListParser>(address_family, cfg_option_def);
return (parser);
}
// ****************** ClientClassDefListParser ************************
ClientClassDictionaryPtr
ClientClassDefListParser::parse(ConstElementPtr client_class_def_list,
uint16_t family, bool check_dependencies) {
ClientClassDictionaryPtr dictionary(new ClientClassDictionary());
for (auto const& client_class_def : client_class_def_list->listValue()) {
ClientClassDefParser parser;
parser.parse(dictionary, client_class_def, family, true, check_dependencies);
}
return (dictionary);
}
} // end of namespace isc::dhcp
} // end of namespace isc
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