1 // Copyright (C) 2011-2021 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/dhcp4.h>
9 #include <dhcp/libdhcp++.h>
10 #include <dhcp/option.h>
11 #include <dhcp/option_space.h>
12 #include <exceptions/exceptions.h>
13 #include <util/encode/hex.h>
14 #include <util/io_utilities.h>
15
16 #include <boost/make_shared.hpp>
17
18 #include <iomanip>
19 #include <list>
20 #include <sstream>
21
22 #include <arpa/inet.h>
23 #include <stdint.h>
24 #include <string.h>
25
26 using namespace std;
27 using namespace isc::util;
28
29 namespace isc {
30 namespace dhcp {
31
32 OptionPtr
factory(Option::Universe u,uint16_t type,const OptionBuffer & buf)33 Option::factory(Option::Universe u,
34 uint16_t type,
35 const OptionBuffer& buf) {
36 return(LibDHCP::optionFactory(u, type, buf));
37 }
38
39
Option(Universe u,uint16_t type)40 Option::Option(Universe u, uint16_t type)
41 :universe_(u), type_(type) {
42 check();
43 }
44
Option(Universe u,uint16_t type,const OptionBuffer & data)45 Option::Option(Universe u, uint16_t type, const OptionBuffer& data)
46 :universe_(u), type_(type), data_(data) {
47 check();
48 }
49
Option(Universe u,uint16_t type,OptionBufferConstIter first,OptionBufferConstIter last)50 Option::Option(Universe u, uint16_t type, OptionBufferConstIter first,
51 OptionBufferConstIter last)
52 :universe_(u), type_(type), data_(first, last) {
53 check();
54 }
55
Option(const Option & option)56 Option::Option(const Option& option)
57 : universe_(option.universe_), type_(option.type_),
58 data_(option.data_), options_(),
59 encapsulated_space_(option.encapsulated_space_) {
60 option.getOptionsCopy(options_);
61 }
62
63 OptionPtr
create(Universe u,uint16_t type)64 Option::create(Universe u, uint16_t type) {
65 return (boost::make_shared<Option>(u, type));
66 }
67
68 OptionPtr
create(Universe u,uint16_t type,const OptionBuffer & data)69 Option::create(Universe u, uint16_t type, const OptionBuffer& data) {
70 return (boost::make_shared<Option>(u, type, data));
71 }
72
73 Option&
operator =(const Option & rhs)74 Option::operator=(const Option& rhs) {
75 if (&rhs != this) {
76 universe_ = rhs.universe_;
77 type_ = rhs.type_;
78 data_ = rhs.data_;
79 rhs.getOptionsCopy(options_);
80 encapsulated_space_ = rhs.encapsulated_space_;
81 }
82 return (*this);
83 }
84
85 OptionPtr
clone() const86 Option::clone() const {
87 return (cloneInternal<Option>());
88 }
89
90 void
check() const91 Option::check() const {
92 if ( (universe_ != V4) && (universe_ != V6) ) {
93 isc_throw(BadValue, "Invalid universe type specified. "
94 << "Only V4 and V6 are allowed.");
95 }
96
97 if (universe_ == V4) {
98
99 if (type_ > 255) {
100 isc_throw(OutOfRange, "DHCPv4 Option type " << type_ << " is too big. "
101 << "For DHCPv4 allowed type range is 0..255");
102 } else if (data_.size() > 255) {
103 isc_throw(OutOfRange, "DHCPv4 Option " << type_ << " is too big.");
104 /// TODO Larger options can be stored as separate instances
105 /// of DHCPv4 options. Clients MUST concatenate them.
106 /// Fortunately, there are no such large options used today.
107 }
108 }
109
110 // no need to check anything for DHCPv6. It allows full range (0-64k) of
111 // both types and data size.
112 }
113
pack(isc::util::OutputBuffer & buf) const114 void Option::pack(isc::util::OutputBuffer& buf) const {
115 // Write a header.
116 packHeader(buf);
117 // Write data.
118 if (!data_.empty()) {
119 buf.writeData(&data_[0], data_.size());
120 }
121 // Write sub-options.
122 packOptions(buf);
123 }
124
125 void
packHeader(isc::util::OutputBuffer & buf) const126 Option::packHeader(isc::util::OutputBuffer& buf) const {
127 if (universe_ == V4) {
128 if (len() > 255) {
129 isc_throw(OutOfRange, "DHCPv4 Option " << type_ << " is too big. "
130 << "At most 255 bytes are supported.");
131 /// TODO Larger options can be stored as separate instances
132 /// of DHCPv4 options. Clients MUST concatenate them.
133 /// Fortunately, there are no such large options used today.
134 }
135
136 buf.writeUint8(type_);
137 buf.writeUint8(len() - getHeaderLen());
138
139 } else {
140 buf.writeUint16(type_);
141 buf.writeUint16(len() - getHeaderLen());
142 }
143 }
144
145 void
packOptions(isc::util::OutputBuffer & buf) const146 Option::packOptions(isc::util::OutputBuffer& buf) const {
147 switch (universe_) {
148 case V4:
149 LibDHCP::packOptions4(buf, options_);
150 return;
151 case V6:
152 LibDHCP::packOptions6(buf, options_);
153 return;
154 default:
155 isc_throw(isc::BadValue, "Invalid universe type " << universe_);
156 }
157 }
158
unpack(OptionBufferConstIter begin,OptionBufferConstIter end)159 void Option::unpack(OptionBufferConstIter begin,
160 OptionBufferConstIter end) {
161 setData(begin, end);
162 }
163
164 void
unpackOptions(const OptionBuffer & buf)165 Option::unpackOptions(const OptionBuffer& buf) {
166 list<uint16_t> deferred;
167 switch (universe_) {
168 case V4:
169 LibDHCP::unpackOptions4(buf, getEncapsulatedSpace(),
170 options_, deferred,
171 getType() == DHO_VENDOR_ENCAPSULATED_OPTIONS);
172 return;
173 case V6:
174 LibDHCP::unpackOptions6(buf, getEncapsulatedSpace(), options_);
175 return;
176 default:
177 isc_throw(isc::BadValue, "Invalid universe type " << universe_);
178 }
179 }
180
len() const181 uint16_t Option::len() const {
182 // Returns length of the complete option (data length + DHCPv4/DHCPv6
183 // option header)
184
185 // length of the whole option is header and data stored in this option...
186 size_t length = getHeaderLen() + data_.size();
187
188 // ... and sum of lengths of all suboptions
189 for (OptionCollection::const_iterator it = options_.begin();
190 it != options_.end();
191 ++it) {
192 length += (*it).second->len();
193 }
194
195 // note that this is not equal to length field. This value denotes
196 // number of bytes required to store this option. length option should
197 // contain (len()-getHeaderLen()) value.
198 return (static_cast<uint16_t>(length));
199 }
200
201 bool
valid() const202 Option::valid() const {
203 if (universe_ != V4 &&
204 universe_ != V6) {
205 return (false);
206 }
207
208 return (true);
209 }
210
getOption(uint16_t opt_type) const211 OptionPtr Option::getOption(uint16_t opt_type) const {
212 isc::dhcp::OptionCollection::const_iterator x =
213 options_.find(opt_type);
214 if ( x != options_.end() ) {
215 return (*x).second;
216 }
217 return OptionPtr(); // NULL
218 }
219
220 void
getOptionsCopy(OptionCollection & options_copy) const221 Option::getOptionsCopy(OptionCollection& options_copy) const {
222 OptionCollection local_options;
223 for (OptionCollection::const_iterator it = options_.begin();
224 it != options_.end(); ++it) {
225 OptionPtr copy = it->second->clone();
226 local_options.insert(std::make_pair(it->second->getType(),
227 copy));
228 }
229 // All options copied successfully, so assign them to the output
230 // parameter.
231 options_copy.swap(local_options);
232 }
233
delOption(uint16_t opt_type)234 bool Option::delOption(uint16_t opt_type) {
235 isc::dhcp::OptionCollection::iterator x = options_.find(opt_type);
236 if ( x != options_.end() ) {
237 options_.erase(x);
238 return true; // delete successful
239 }
240 return (false); // option not found, can't delete
241 }
242
243
toText(int indent) const244 std::string Option::toText(int indent) const {
245 std::stringstream output;
246 output << headerToText(indent) << ": ";
247
248 for (unsigned int i = 0; i < data_.size(); i++) {
249 if (i) {
250 output << ":";
251 }
252 output << setfill('0') << setw(2) << hex
253 << static_cast<unsigned short>(data_[i]);
254 }
255
256 // Append suboptions.
257 output << suboptionsToText(indent + 2);
258
259 return (output.str());
260 }
261
262 std::string
toString() const263 Option::toString() const {
264 /// @todo: Implement actual conversion in derived classes.
265 return (toText(0));
266 }
267
268 std::vector<uint8_t>
toBinary(const bool include_header) const269 Option::toBinary(const bool include_header) const {
270 OutputBuffer buf(len());
271 try {
272 // If the option is too long, exception will be thrown. We allow
273 // for this exception to propagate to not mask this error.
274 pack(buf);
275
276 } catch (const std::exception &ex) {
277 isc_throw(OutOfRange, "unable to obtain hexadecimal representation"
278 " of option " << getType() << ": " << ex.what());
279 }
280 const uint8_t* option_data = static_cast<const uint8_t*>(buf.getData());
281
282 // Assign option data to a vector, with or without option header depending
283 // on the value of "include_header" flag.
284 std::vector<uint8_t> option_vec(option_data + (include_header ? 0 : getHeaderLen()),
285 option_data + buf.getLength());
286 return (option_vec);
287 }
288
289 std::string
toHexString(const bool include_header) const290 Option::toHexString(const bool include_header) const {
291 // Prepare binary version of the option.
292 std::vector<uint8_t> option_vec = toBinary(include_header);
293
294 // Return hexadecimal representation prepended with 0x or empty string
295 // if option has no payload and the header fields are excluded.
296 std::ostringstream s;
297 if (!option_vec.empty()) {
298 s << "0x" << encode::encodeHex(option_vec);
299 }
300 return (s.str());
301 }
302
303 std::string
headerToText(const int indent,const std::string & type_name) const304 Option::headerToText(const int indent, const std::string& type_name) const {
305 std::stringstream output;
306 for (int i = 0; i < indent; i++)
307 output << " ";
308
309 int field_len = (getUniverse() == V4 ? 3 : 5);
310 output << "type=" << std::setw(field_len) << std::setfill('0')
311 << type_;
312
313 if (!type_name.empty()) {
314 output << "(" << type_name << ")";
315 }
316
317 output << ", len=" << std::setw(field_len) << std::setfill('0')
318 << len()-getHeaderLen();
319 return (output.str());
320 }
321
322 std::string
suboptionsToText(const int indent) const323 Option::suboptionsToText(const int indent) const {
324 std::stringstream output;
325
326 if (!options_.empty()) {
327 output << "," << std::endl << "options:";
328 for (OptionCollection::const_iterator opt = options_.begin();
329 opt != options_.end(); ++opt) {
330 output << std::endl << (*opt).second->toText(indent);
331 }
332 }
333
334 return (output.str());
335 }
336
337 uint16_t
getHeaderLen() const338 Option::getHeaderLen() const {
339 switch (universe_) {
340 case V4:
341 return OPTION4_HDR_LEN; // header length for v4
342 case V6:
343 return OPTION6_HDR_LEN; // header length for v6
344 }
345 return 0; // should not happen
346 }
347
addOption(OptionPtr opt)348 void Option::addOption(OptionPtr opt) {
349 if (universe_ == V4) {
350 // check for uniqueness (DHCPv4 options must be unique)
351 if (getOption(opt->getType())) {
352 isc_throw(BadValue, "Option " << opt->getType()
353 << " already present in this message.");
354 }
355 }
356 options_.insert(make_pair(opt->getType(), opt));
357 }
358
getUint8() const359 uint8_t Option::getUint8() const {
360 if (data_.size() < sizeof(uint8_t) ) {
361 isc_throw(OutOfRange, "Attempt to read uint8 from option " << type_
362 << " that has size " << data_.size());
363 }
364 return (data_[0]);
365 }
366
getUint16() const367 uint16_t Option::getUint16() const {
368 // readUint16() checks and throws OutOfRange if data_ is too small.
369 return (readUint16(&data_[0], data_.size()));
370 }
371
getUint32() const372 uint32_t Option::getUint32() const {
373 // readUint32() checks and throws OutOfRange if data_ is too small.
374 return (readUint32(&data_[0], data_.size()));
375 }
376
setUint8(uint8_t value)377 void Option::setUint8(uint8_t value) {
378 data_.resize(sizeof(value));
379 data_[0] = value;
380 }
381
setUint16(uint16_t value)382 void Option::setUint16(uint16_t value) {
383 data_.resize(sizeof(value));
384 writeUint16(value, &data_[0], data_.size());
385 }
386
setUint32(uint32_t value)387 void Option::setUint32(uint32_t value) {
388 data_.resize(sizeof(value));
389 writeUint32(value, &data_[0], data_.size());
390 }
391
equals(const OptionPtr & other) const392 bool Option::equals(const OptionPtr& other) const {
393 return (equals(*other));
394 }
395
equals(const Option & other) const396 bool Option::equals(const Option& other) const {
397 return ( (getType() == other.getType()) &&
398 (getData() == other.getData()) );
399 }
400
~Option()401 Option::~Option() {
402
403 }
404
405 bool Option::lenient_parsing_;
406
407 } // end of isc::dhcp namespace
408 } // end of isc namespace
409