Kea 2.5.4
client_class_def_parser.cc
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1// Copyright (C) 2015-2023 Internet Systems Consortium, Inc. ("ISC")
2//
3// This Source Code Form is subject to the terms of the Mozilla Public
4// License, v. 2.0. If a copy of the MPL was not distributed with this
5// file, You can obtain one at http://mozilla.org/MPL/2.0/.
6
7#include <config.h>
8#include <dhcp/libdhcp++.h>
9#include <dhcpsrv/cfgmgr.h>
15#include <eval/eval_context.h>
16#include <asiolink/io_address.h>
17#include <asiolink/io_error.h>
18
19#include <boost/foreach.hpp>
20#include <algorithm>
21#include <sstream>
22
23using namespace isc::data;
24using namespace isc::asiolink;
25using namespace isc::util;
26using namespace std;
27
31
32namespace isc {
33namespace dhcp {
34
35// ********************** ExpressionParser ****************************
36
37void
39 ConstElementPtr expression_cfg,
40 uint16_t family,
41 EvalContext::CheckDefined check_defined,
42 EvalContext::ParserType parser_type) {
43 if (expression_cfg->getType() != Element::string) {
44 isc_throw(DhcpConfigError, "expression ["
45 << expression_cfg->str() << "] must be a string, at ("
46 << expression_cfg->getPosition() << ")");
47 }
48
49 // Get the expression's text via getValue() as the text returned
50 // by str() enclosed in quotes.
51 std::string value;
52 expression_cfg->getValue(value);
53
54 if (parser_type == EvalContext::PARSER_STRING && value.empty()) {
55 isc_throw(DhcpConfigError, "expression can not be empty at ("
56 << expression_cfg->getPosition() << ")");
57 }
58
59 try {
60 EvalContext eval_ctx(family == AF_INET ? Option::V4 : Option::V6,
61 check_defined);
62 eval_ctx.parseString(value, parser_type);
63 expression.reset(new Expression());
64 *expression = eval_ctx.expression;
65 } catch (const std::exception& ex) {
66 // Append position if there is a failure.
68 "expression: [" << value
69 << "] error: " << ex.what() << " at ("
70 << expression_cfg->getPosition() << ")");
71 }
72}
73
74// ********************** ClientClassDefParser ****************************
75
76void
78 ConstElementPtr class_def_cfg,
79 uint16_t family,
80 bool append_error_position,
81 bool check_dependencies) {
82 // name is now mandatory, so let's deal with it first.
83 std::string name = getString(class_def_cfg, "name");
84 if (name.empty()) {
86 "not empty parameter 'name' is required "
87 << getPosition("name", class_def_cfg) << ")");
88 }
89
90 EvalContext::ParserType parser_type = EvalContext::PARSER_BOOL;
91
92 // Let's try to parse the template-test expression
93 bool is_template = false;
94
95 // Parse matching expression
96 ExpressionPtr match_expr;
97 ConstElementPtr test_cfg = class_def_cfg->get("test");
98 ConstElementPtr template_test_cfg = class_def_cfg->get("template-test");
99 if (test_cfg && template_test_cfg) {
100 isc_throw(DhcpConfigError, "can not use both 'test' and 'template-test' ("
101 << test_cfg->getPosition() << ") and ("
102 << template_test_cfg->getPosition() << ")");
103 }
104 std::string test;
105 bool depend_on_known = false;
106 EvalContext::CheckDefined check_defined = EvalContext::acceptAll;
107 if (template_test_cfg) {
108 test_cfg = template_test_cfg;
109 parser_type = EvalContext::PARSER_STRING;
110 is_template = true;
111 } else {
112 check_defined = [&class_dictionary, &depend_on_known, check_dependencies](const ClientClass& cclass) {
113 return (!check_dependencies || isClientClassDefined(class_dictionary, depend_on_known, cclass));
114 };
115 }
116
117 if (test_cfg) {
118 ExpressionParser parser;
119 parser.parse(match_expr, test_cfg, family, check_defined, parser_type);
120 test = test_cfg->stringValue();
121 }
122
123 // Parse option def
124 CfgOptionDefPtr defs(new CfgOptionDef());
125 ConstElementPtr option_defs = class_def_cfg->get("option-def");
126 if (option_defs) {
127 // Apply defaults
129 family == AF_INET ?
132
133 OptionDefParser parser(family);
134 BOOST_FOREACH(ConstElementPtr option_def, option_defs->listValue()) {
135 OptionDefinitionPtr def = parser.parse(option_def);
136
137 // Verify if the definition is for an option which is in a deferred
138 // processing list.
139 if (!LibDHCP::shouldDeferOptionUnpack(def->getOptionSpaceName(),
140 def->getCode())) {
142 "Not allowed option definition for code '"
143 << def->getCode() << "' in space '"
144 << def->getOptionSpaceName() << "' at ("
145 << option_def->getPosition() << ")");
146 }
147 try {
148 defs->add(def);
149 } catch (const std::exception& ex) {
150 // Sanity check: it should never happen
151 isc_throw(DhcpConfigError, ex.what() << " ("
152 << option_def->getPosition() << ")");
153 }
154 }
155 }
156
157 // Parse option data
158 CfgOptionPtr options(new CfgOption());
159 ConstElementPtr option_data = class_def_cfg->get("option-data");
160 if (option_data) {
161 auto opts_parser = createOptionDataListParser(family, defs);
162 opts_parser->parse(options, option_data);
163 }
164
165 // Parse user context
166 ConstElementPtr user_context = class_def_cfg->get("user-context");
167 if (user_context) {
168 if (user_context->getType() != Element::map) {
169 isc_throw(isc::dhcp::DhcpConfigError, "User context has to be a map ("
170 << user_context->getPosition() << ")");
171 }
172 }
173
174 // Let's try to parse the only-if-required flag
175 bool required = false;
176 if (class_def_cfg->contains("only-if-required")) {
177 required = getBoolean(class_def_cfg, "only-if-required");
178 }
179
180 // Let's try to parse the next-server field
181 IOAddress next_server("0.0.0.0");
182 if (class_def_cfg->contains("next-server")) {
183 std::string next_server_txt = getString(class_def_cfg, "next-server");
184 try {
185 next_server = IOAddress(next_server_txt);
186 } catch (const IOError& ex) {
188 "Invalid next-server value specified: '"
189 << next_server_txt << "' ("
190 << getPosition("next-server", class_def_cfg) << ")");
191 }
192
193 if (next_server.getFamily() != AF_INET) {
194 isc_throw(DhcpConfigError, "Invalid next-server value: '"
195 << next_server_txt << "', must be IPv4 address ("
196 << getPosition("next-server", class_def_cfg) << ")");
197 }
198
199 if (next_server.isV4Bcast()) {
200 isc_throw(DhcpConfigError, "Invalid next-server value: '"
201 << next_server_txt << "', must not be a broadcast ("
202 << getPosition("next-server", class_def_cfg) << ")");
203 }
204 }
205
206 // Let's try to parse server-hostname
207 std::string sname;
208 if (class_def_cfg->contains("server-hostname")) {
209 sname = getString(class_def_cfg, "server-hostname");
210
211 if (sname.length() >= Pkt4::MAX_SNAME_LEN) {
212 isc_throw(DhcpConfigError, "server-hostname must be at most "
213 << Pkt4::MAX_SNAME_LEN - 1 << " bytes long, it is "
214 << sname.length() << " ("
215 << getPosition("server-hostname", class_def_cfg) << ")");
216 }
217 }
218
219 // Let's try to parse boot-file-name
220 std::string filename;
221 if (class_def_cfg->contains("boot-file-name")) {
222 filename = getString(class_def_cfg, "boot-file-name");
223
224 if (filename.length() > Pkt4::MAX_FILE_LEN) {
225 isc_throw(DhcpConfigError, "boot-file-name must be at most "
226 << Pkt4::MAX_FILE_LEN - 1 << " bytes long, it is "
227 << filename.length() << " ("
228 << getPosition("boot-file-name", class_def_cfg) << ")");
229 }
230 }
231
232 Optional<uint32_t> offer_lft;
233 if (class_def_cfg->contains("offer-lifetime")) {
234 auto value = getInteger(class_def_cfg, "offer-lifetime");
235 if (value < 0) {
236 isc_throw(DhcpConfigError, "the value of offer-lifetime '"
237 << value << "' must be a positive number ("
238 << getPosition("offer-lifetime", class_def_cfg) << ")");
239 }
240
241 offer_lft = value;
242 }
243
244 // Parse valid lifetime triplet.
245 Triplet<uint32_t> valid_lft = parseIntTriplet(class_def_cfg, "valid-lifetime");
246
247 Triplet<uint32_t> preferred_lft;
248 if (family != AF_INET) {
249 // Parse preferred lifetime triplet.
250 preferred_lft = parseIntTriplet(class_def_cfg, "preferred-lifetime");
251 }
252
253 // Sanity checks on built-in classes
254 for (auto bn : builtinNames) {
255 if (name == bn) {
256 if (required) {
257 isc_throw(DhcpConfigError, "built-in class '" << name
258 << "' only-if-required flag must be false");
259 }
260 if (!test.empty()) {
261 isc_throw(DhcpConfigError, "built-in class '" << name
262 << "' test expression must be empty");
263 }
264 }
265 }
266
267 // Sanity checks on DROP
268 if (name == "DROP") {
269 if (required) {
270 isc_throw(DhcpConfigError, "special class '" << name
271 << "' only-if-required flag must be false");
272 }
273 // depend_on_known is now allowed
274 }
275
276 // Add the client class definition
277 try {
278 class_dictionary->addClass(name, match_expr, test, required,
279 depend_on_known, options, defs,
280 user_context, next_server, sname, filename,
281 valid_lft, preferred_lft, is_template, offer_lft);
282 } catch (const std::exception& ex) {
283 std::ostringstream s;
284 s << "Can't add class: " << ex.what();
285 // Append position of the error in JSON string if required.
286 if (append_error_position) {
287 s << " (" << class_def_cfg->getPosition() << ")";
288 }
289 isc_throw(DhcpConfigError, s.str());
290 }
291}
292
293void
295 const uint16_t family) {
296 // Make sure that the client class definition is stored in a map.
297 if (!class_def_cfg || (class_def_cfg->getType() != Element::map)) {
298 isc_throw(DhcpConfigError, "client class definition is not a map");
299 }
300
301 // Common v4 and v6 parameters supported for the client class.
302 static std::set<std::string> supported_params = { "name",
303 "test",
304 "option-data",
305 "user-context",
306 "only-if-required",
307 "valid-lifetime",
308 "min-valid-lifetime",
309 "max-valid-lifetime",
310 "template-test"};
311
312 // The v4 client class supports additional parameters.
313 static std::set<std::string> supported_params_v4 = { "option-def",
314 "next-server",
315 "server-hostname",
316 "boot-file-name" };
317
318 // The v6 client class supports additional parameters.
319 static std::set<std::string> supported_params_v6 = { "preferred-lifetime",
320 "min-preferred-lifetime",
321 "max-preferred-lifetime" };
322
323 // Iterate over the specified parameters and check if they are all supported.
324 for (auto name_value_pair : class_def_cfg->mapValue()) {
325 if ((supported_params.count(name_value_pair.first) > 0) ||
326 ((family == AF_INET) && (supported_params_v4.count(name_value_pair.first) > 0)) ||
327 ((family != AF_INET) && (supported_params_v6.count(name_value_pair.first) > 0))) {
328 continue;
329 } else {
330 isc_throw(DhcpConfigError, "unsupported client class parameter '"
331 << name_value_pair.first << "'");
332 }
333 }
334}
335
336boost::shared_ptr<OptionDataListParser>
338 CfgOptionDefPtr cfg_option_def) const {
339 auto parser = boost::make_shared<OptionDataListParser>(address_family, cfg_option_def);
340 return (parser);
341}
342
343// ****************** ClientClassDefListParser ************************
344
347 uint16_t family, bool check_dependencies) {
349 BOOST_FOREACH(ConstElementPtr client_class_def,
350 client_class_def_list->listValue()) {
352 parser.parse(dictionary, client_class_def, family, true, check_dependencies);
353 }
354 return (dictionary);
355}
356
357} // end of namespace isc::dhcp
358} // end of namespace isc
virtual const char * what() const
Returns a C-style character string of the cause of the exception.
static size_t setListDefaults(isc::data::ConstElementPtr list, const SimpleDefaults &default_values)
Sets the default values for all entries in a list.
static const data::Element::Position & getPosition(const std::string &name, const data::ConstElementPtr parent)
Utility method that returns position of an element.
static std::string getString(isc::data::ConstElementPtr scope, const std::string &name)
Returns a string parameter from a scope.
const isc::util::Triplet< uint32_t > parseIntTriplet(const data::ConstElementPtr &scope, const std::string &name)
Parses an integer triplet.
static bool getBoolean(isc::data::ConstElementPtr scope, const std::string &name)
Returns a boolean parameter from a scope.
static int64_t getInteger(isc::data::ConstElementPtr scope, const std::string &name)
Returns an integer parameter from a scope.
Represents option definitions used by the DHCP server.
Represents option data configuration for the DHCP server.
Definition: cfg_option.h:351
ClientClassDictionaryPtr parse(isc::data::ConstElementPtr class_def_list, uint16_t family, bool check_dependencies=true)
Parse configuration entries.
Parser for a single client class definition.
virtual boost::shared_ptr< OptionDataListParser > createOptionDataListParser(const uint16_t address_family, CfgOptionDefPtr cfg_option_def) const
Returns an instance of the OptionDataListParser to be used in parsing the option-data structure.
void parse(ClientClassDictionaryPtr &class_dictionary, isc::data::ConstElementPtr client_class_def, uint16_t family, bool append_error_position=true, bool check_dependencies=true)
Parses an entry that describes single client class definition.
void checkParametersSupported(const isc::data::ConstElementPtr &class_def_cfg, const uint16_t family)
Iterates over class parameters and checks if they are supported.
Maintains a list of ClientClassDef's.
To be removed. Please use ConfigError instead.
Parser for a logical expression.
void parse(ExpressionPtr &expression, isc::data::ConstElementPtr expression_cfg, uint16_t family, isc::eval::EvalContext::CheckDefined check_defined=isc::eval::EvalContext::acceptAll, isc::eval::EvalContext::ParserType parser_type=isc::eval::EvalContext::PARSER_BOOL)
Parses an expression configuration element into an Expression.
static bool shouldDeferOptionUnpack(const std::string &space, const uint16_t code)
Checks if an option unpacking has to be deferred.
Definition: libdhcp++.cc:278
Parser for a single option definition.
Definition: dhcp_parsers.h:228
OptionDefinitionPtr parse(isc::data::ConstElementPtr option_def)
Parses an entry that describes single option definition.
Definition: dhcp_parsers.cc:98
static const size_t MAX_SNAME_LEN
length of the SNAME field in DHCPv4 message
Definition: pkt4.h:44
static const size_t MAX_FILE_LEN
length of the FILE field in DHCPv4 message
Definition: pkt4.h:47
static const isc::data::SimpleDefaults OPTION4_DEF_DEFAULTS
This table defines default values for option definitions in DHCPv4.
static const isc::data::SimpleDefaults OPTION6_DEF_DEFAULTS
This table defines default values for option definitions in DHCPv6.
Evaluation context, an interface to the expression evaluation.
Definition: eval_context.h:34
std::function< bool(const ClientClass &)> CheckDefined
Type of the check defined function.
Definition: eval_context.h:44
bool parseString(const std::string &str, ParserType type=PARSER_BOOL)
Run the parser on the string specified.
Definition: eval_context.cc:37
ParserType
Specifies what type of expression the parser is expected to see.
Definition: eval_context.h:38
isc::dhcp::Expression expression
Parsed expression (output tokens are stored here)
Definition: eval_context.h:67
Defines classes for storing client class definitions.
Parsers for client class definitions.
#define isc_throw(type, stream)
A shortcut macro to insert known values into exception arguments.
boost::shared_ptr< const Element > ConstElementPtr
Definition: data.h:29
std::string ClientClass
Defines a single class name.
Definition: classify.h:42
boost::shared_ptr< CfgOption > CfgOptionPtr
Non-const pointer.
Definition: cfg_option.h:803
boost::shared_ptr< CfgOptionDef > CfgOptionDefPtr
Non-const pointer.
boost::shared_ptr< OptionDefinition > OptionDefinitionPtr
Pointer to option definition object.
boost::shared_ptr< Expression > ExpressionPtr
Definition: token.h:30
boost::shared_ptr< ClientClassDictionary > ClientClassDictionaryPtr
Defines a pointer to a ClientClassDictionary.
bool isClientClassDefined(ClientClassDictionaryPtr &class_dictionary, bool &depend_on_known, const ClientClass &client_class)
Check if a client class name is already defined, i.e.
std::vector< TokenPtr > Expression
This is a structure that holds an expression converted to RPN.
Definition: token.h:28
std::list< std::string > builtinNames
List of classes for which test expressions cannot be defined.
Definition: edns.h:19
Defines the logger used by the top-level component of kea-lfc.