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// Copyright (C) 2023-2024 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/option6_dnr.h>
using namespace isc::asiolink;
using namespace isc::util;
namespace isc {
namespace dhcp {
Option6Dnr::Option6Dnr(OptionBufferConstIter begin,
OptionBufferConstIter end,
bool convenient_notation)
: Option(V6, D6O_V6_DNR), DnrInstance(V6), convenient_notation_(convenient_notation) {
unpack(begin, end);
}
OptionPtr
Option6Dnr::clone() const {
return (cloneInternal<Option6Dnr>());
}
void
Option6Dnr::pack(util::OutputBuffer& buf, bool check) const {
packHeader(buf, check);
buf.writeUint16(service_priority_);
buf.writeUint16(adn_length_);
packAdn(buf);
if (adn_only_mode_) {
return;
}
buf.writeUint16(addr_length_);
packAddresses(buf);
packSvcParams(buf);
}
void
Option6Dnr::packAddresses(util::OutputBuffer& buf) const {
for (auto const& address : ip_addresses_) {
if (!address.isV6()) {
isc_throw(isc::BadValue, getLogPrefix()
<< address.toText() << " is not an IPv6 address");
}
buf.writeData(&address.toBytes()[0], V6ADDRESS_LEN);
}
}
void
Option6Dnr::unpack(OptionBufferConstIter begin, OptionBufferConstIter end) {
if (convenient_notation_) {
// parse convenient notation
std::string config_txt = std::string(begin, end);
parseConfigData(config_txt);
} else {
if (std::distance(begin, end) < getMinimalLength()) {
isc_throw(OutOfRange, getLogPrefix()
<< "data truncated to size " << std::distance(begin, end));
}
setData(begin, end);
// First two octets of Option data is Service Priority - this is mandatory field.
unpackServicePriority(begin);
// Next come two octets of ADN Length plus the ADN data itself (variable length).
// This is Opaque Data Tuple so let's use this class to retrieve the ADN data.
unpackAdn(begin, end);
if (begin == end) {
// ADN only mode, other fields are not included.
return;
}
adn_only_mode_ = false;
unpackAddresses(begin, end);
// SvcParams (variable length) field is last.
unpackSvcParams(begin, end);
}
}
std::string
Option6Dnr::toText(int indent) const {
std::ostringstream stream;
std::string in(indent, ' '); // base indentation
stream << in << "type=" << type_ << "(V6_DNR), "
<< "len=" << (len() - getHeaderLen()) << ", " << getDnrInstanceAsText();
return (stream.str());
}
uint16_t
Option6Dnr::len() const {
return (OPTION6_HDR_LEN + dnrInstanceLen());
}
void
Option6Dnr::unpackAddresses(OptionBufferConstIter& begin, OptionBufferConstIter end) {
if (std::distance(begin, end) < getAddrLengthSize()) {
isc_throw(OutOfRange, getLogPrefix() << "after"
" ADN field, there should be at least "
"2 bytes long Addr Length field");
}
// Next come two octets of Addr Length.
addr_length_ = isc::util::readUint16(&(*begin), getAddrLengthSize());
begin += getAddrLengthSize();
// It MUST be a multiple of 16.
if ((addr_length_ % V6ADDRESS_LEN) != 0) {
isc_throw(OutOfRange, getLogPrefix()
<< "Addr Len=" << addr_length_ << " is not divisible by 16");
}
// As per draft-ietf-add-dnr 3.1.8:
// If additional data is supplied (i.e. not ADN only mode),
// the option includes at least one valid IP address.
if (addr_length_ == 0) {
isc_throw(OutOfRange, getLogPrefix()
<< "Addr Len=" << addr_length_
<< " but it must contain at least one valid IP address");
}
// Check if IPv6 Address(es) field is not truncated.
if (std::distance(begin, end) < addr_length_) {
isc_throw(OutOfRange, getLogPrefix() << "Addr Len=" << addr_length_
<< " but IPv6 address(es) are truncated to len="
<< std::distance(begin, end));
}
// Let's unpack the ipv6-address(es).
auto addr_end = begin + addr_length_;
while (begin != addr_end) {
try {
ip_addresses_.push_back(IOAddress::fromBytes(AF_INET6, &(*begin)));
} catch (const Exception& ex) {
isc_throw(BadValue, getLogPrefix() << "failed to parse IPv6 address"
<< " - " << ex.what());
}
begin += V6ADDRESS_LEN;
}
}
void
Option6Dnr::parseConfigData(const std::string& config_txt){
// This parses convenient option config notation.
// The config to be parsed may contain escaped characters like "\\," or "\\|".
// Example configs are below (first contains recommended resolvers' IP addresses, and SvcParams;
// second is an example of ADN-only mode):
//
// "name": "v6-dnr",
// "data": "100, dot1.example.org., 2001:db8::1 2001:db8::2, alpn=dot\\,doq\\,h2\\,h3 port=8530 dohpath=/q{?dns}"
//
// "name": "v6-dnr",
// "data": "200, resolver.example."
// get tokens using comma separator with double backslash escaping enabled
std::vector<std::string> tokens = str::tokens(config_txt, std::string(","), true);
if (tokens.size() < 2) {
isc_throw(BadValue, getLogPrefix() << "Option config requires at least comma separated "
<< "Service Priority and ADN");
}
if (tokens.size() > 4) {
isc_throw(BadValue, getLogPrefix() << "Option config supports maximum 4 comma separated "
<< "fields: Service Priority, ADN, resolver IP "
<< "address/es and SvcParams");
}
// parse Service Priority
std::string txt_svc_priority = str::trim(tokens[0]);
try {
service_priority_ = boost::lexical_cast<uint16_t>(txt_svc_priority);
} catch (const std::exception& e) {
isc_throw(BadValue, getLogPrefix() << "Given service priority " + txt_svc_priority
<< " cannot be parsed into uint_16 integer. "
<< "Error: " << e.what());
}
// parse ADN
std::string txt_adn = str::trim(tokens[1]);
try {
adn_.reset(new isc::dns::Name(txt_adn, true));
} catch (const std::exception& e) {
isc_throw(InvalidOptionDnrDomainName, getLogPrefix()
<< "Given ADN " + txt_adn
<< " cannot be parsed into fully qualified "
<< "domain-name. "
<< "Error: " << e.what());
}
adn_length_ = adn_->getLength();
if (adn_length_ == 0) {
isc_throw(InvalidOptionDnrDomainName, getLogPrefix()
<< "Mandatory Authentication Domain Name fully "
"qualified domain-name is missing");
}
if (tokens.size() > 2) {
setAdnOnlyMode(false);
// parse resolver IP address/es
std::string txt_addresses = str::trim(tokens[2]);
// IP addresses are separated with space
std::vector<std::string> addresses = str::tokens(txt_addresses, std::string(" "));
for (auto const& txt_addr : addresses) {
try {
ip_addresses_.push_back(IOAddress(str::trim(txt_addr)));
} catch (const Exception& e) {
isc_throw(BadValue, getLogPrefix() << "Given string " + txt_addr
<< " cannot be parsed into IPv6 address. "
<< "Error: " << e.what());
}
}
// As per RFC9463 section 3.1.8:
// (If ADN-only mode is not used)
// The option includes at least one valid IP address.
if (ip_addresses_.empty()) {
isc_throw(BadValue, getLogPrefix() << "Option config requires at least one valid IP "
<< "address.");
}
addr_length_ = ip_addresses_.size() * V6ADDRESS_LEN;
}
if (tokens.size() == 4) {
// parse Service Parameters
std::string txt_svc_params = str::trim(tokens[3]);
// SvcParamKey=SvcParamValue pairs are separated with space
std::vector<std::string> svc_params_pairs = str::tokens(txt_svc_params, std::string(" "));
std::vector<std::string> alpn_ids_tokens;
OpaqueDataTuple svc_param_val_tuple(OpaqueDataTuple::LENGTH_2_BYTES);
OutputBuffer out_buf(2);
for (auto const& svc_param_pair : svc_params_pairs) {
std::vector<std::string> key_val_tokens = str::tokens(str::trim(svc_param_pair), "=");
if (key_val_tokens.size() != 2) {
isc_throw(InvalidOptionDnrSvcParams,
getLogPrefix() << "Wrong Svc Params syntax - SvcParamKey=SvcParamValue "
<< "pair syntax must be used");
}
// SvcParam Key related checks come below.
std::string svc_param_key = str::trim(key_val_tokens[0]);
// As per RFC9463 Section 3.1.8:
// The service parameters do not include "ipv4hint" or "ipv6hint" parameters.
if (FORBIDDEN_SVC_PARAMS.find(svc_param_key) != FORBIDDEN_SVC_PARAMS.end()) {
isc_throw(InvalidOptionDnrSvcParams,
getLogPrefix() << "Wrong Svc Params syntax - key "
<< svc_param_key << " must not be used");
}
// Check if SvcParamKey is known in https://www.iana.org/assignments/dns-svcb/dns-svcb.xhtml
auto svc_params_iterator = SVC_PARAMS.find(svc_param_key);
if (svc_params_iterator == SVC_PARAMS.end()) {
isc_throw(InvalidOptionDnrSvcParams,
getLogPrefix() << "Wrong Svc Params syntax - key "
<< svc_param_key
<< " not found in SvcParamKeys registry");
}
// Check if SvcParamKey usage is supported by DNR DHCP option.
// Note that SUPPORTED_SVC_PARAMS set may expand in future.
uint16_t num_svc_param_key = svc_params_iterator->second;
if (SUPPORTED_SVC_PARAMS.find(num_svc_param_key) == SUPPORTED_SVC_PARAMS.end()) {
isc_throw(InvalidOptionDnrSvcParams,
getLogPrefix() << "Wrong Svc Params syntax - key "
<< svc_param_key
<< " not supported in DNR option SvcParams");
}
// As per RFC9460 Section 2.2:
// SvcParamKeys SHALL appear in increasing numeric order. (...)
// There are no duplicate SvcParamKeys.
//
// We check for duplicates here. Correct ordering is done when option gets packed.
if (svc_params_map_.find(num_svc_param_key) != svc_params_map_.end()) {
isc_throw(InvalidOptionDnrSvcParams,
getLogPrefix() << "Wrong Svc Params syntax - key "
<< svc_param_key
<< " is duplicated.");
}
// SvcParam Val check.
std::string svc_param_val = str::trim(key_val_tokens[1]);
if (svc_param_val.empty()) {
isc_throw(InvalidOptionDnrSvcParams,
getLogPrefix() << "Wrong Svc Params syntax - empty SvcParamValue for key "
<< svc_param_key);
}
svc_param_val_tuple.clear();
switch (num_svc_param_key) {
case 1:
// alpn
// The wire-format value for "alpn" consists of at least one alpn-id prefixed by its
// length as a single octet, and these length-value pairs are concatenated to form
// the SvcParamValue.
alpn_ids_tokens = str::tokens(svc_param_val, std::string(","));
for (auto const& alpn_id : alpn_ids_tokens) {
// Check if alpn-id is known in
// https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml#alpn-protocol-ids
if (ALPN_IDS.find(alpn_id) == ALPN_IDS.end()) {
isc_throw(InvalidOptionDnrSvcParams,
getLogPrefix() << "Wrong Svc Params syntax - alpn-id "
<< alpn_id
<< " not found in ALPN-IDs registry");
}
OpaqueDataTuple alpn_id_tuple(OpaqueDataTuple::LENGTH_1_BYTE);
alpn_id_tuple.append(alpn_id);
alpn_id_tuple.pack(out_buf);
svc_param_val_tuple.append(static_cast<const char*>(out_buf.getData()), out_buf.getLength());
out_buf.clear();
}
svc_params_map_.insert(std::make_pair(num_svc_param_key, svc_param_val_tuple));
break;
case 3:
// port
// The wire format of the SvcParamValue is the corresponding 2-octet numeric value
// in network byte order.
uint16_t port;
try {
port = boost::lexical_cast<uint16_t>(svc_param_val);
} catch (const std::exception& e) {
isc_throw(InvalidOptionDnrSvcParams,
getLogPrefix() << "Wrong Svc Params syntax - given port nr "
<< svc_param_val
<< " cannot be parsed into uint_16 integer. "
<< "Error: " << e.what());
}
out_buf.writeUint16(port);
svc_param_val_tuple.append(static_cast<const char*>(out_buf.getData()), out_buf.getLength());
out_buf.clear();
svc_params_map_.insert(std::make_pair(num_svc_param_key, svc_param_val_tuple));
break;
case 7:
// dohpath
break;
}
}
std::ostringstream stream;
for (auto const& p : SUPPORTED_SVC_PARAMS) {
auto it = svc_params_map_.find(p);
if (it != svc_params_map_.end()) {
out_buf.writeUint16(it->first);
(it->second).pack(out_buf);
stream << str::dumpAsHex(static_cast<const uint8_t*>(out_buf.getData()), out_buf.getLength());
stream << " ";
out_buf.clear();
}
}
isc_throw(BadValue,
getLogPrefix() << "SvcParams: " + txt_svc_params
<< ", packed hex: "
<< stream.str()
);
}
}
} // namespace dhcp
} // namespace isc
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