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/*
* This file is part of PowerDNS or dnsdist.
* Copyright -- PowerDNS.COM B.V. and its contributors
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* In addition, for the avoidance of any doubt, permission is granted to
* link this program with OpenSSL and to (re)distribute the binaries
* produced as the result of such linking.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "ednssubnet.hh"
#include "dns.hh"
namespace
{
struct EDNSSubnetOptsWire
{
uint16_t family;
uint8_t sourceMask;
uint8_t scopeMask;
} GCCPACKATTRIBUTE; // BRRRRR
}
bool getEDNSSubnetOptsFromString(const string& options, EDNSSubnetOpts* eso)
{
// cerr<<"options.size:"<<options.size()<<endl;
return getEDNSSubnetOptsFromString(options.c_str(), options.length(), eso);
}
bool getEDNSSubnetOptsFromString(const char* options, unsigned int len, EDNSSubnetOpts* eso)
{
EDNSSubnetOptsWire esow{};
static_assert(sizeof(esow) == 4, "sizeof(EDNSSubnetOptsWire) must be 4 bytes");
if (len < sizeof(esow)) {
return false;
}
memcpy(&esow, options, sizeof(esow));
esow.family = ntohs(esow.family);
// cerr<<"Family when parsing from string: "<<esow.family<<endl;
ComboAddress address;
unsigned int octetsin = esow.sourceMask > 0 ? (((esow.sourceMask - 1) >> 3) + 1) : 0;
// cerr<<"octetsin:"<<octetsin<<endl;
if (esow.family == 1) {
if (len != sizeof(esow) + octetsin) {
return false;
}
if (octetsin > sizeof(address.sin4.sin_addr.s_addr)) {
return false;
}
address.reset();
address.sin4.sin_family = AF_INET;
if (octetsin > 0) {
memcpy(&address.sin4.sin_addr.s_addr, options + sizeof(esow), octetsin); // NOLINT(cppcoreguidelines-pro-bounds-pointer-arithmetic)
}
}
else if (esow.family == 2) {
if (len != sizeof(esow) + octetsin) {
return false;
}
if (octetsin > sizeof(address.sin6.sin6_addr.s6_addr)) {
return false;
}
address.reset();
address.sin4.sin_family = AF_INET6;
if (octetsin > 0) {
memcpy(&address.sin6.sin6_addr.s6_addr, options + sizeof(esow), octetsin); // NOLINT(cppcoreguidelines-pro-bounds-pointer-arithmetic)
}
}
else {
return false;
}
eso->source = Netmask(address, esow.sourceMask);
/* 'address' has more bits set (potentially) than scopeMask. This leads to odd looking netmasks that promise
more precision than they have. For this reason we truncate the address to scopeMask bits */
address.truncate(esow.scopeMask); // truncate will not throw for odd scopeMasks
eso->scope = Netmask(address, esow.scopeMask);
return true;
}
string makeEDNSSubnetOptsString(const EDNSSubnetOpts& eso)
{
string ret;
EDNSSubnetOptsWire esow{};
uint16_t family = htons(eso.source.getNetwork().sin4.sin_family == AF_INET ? 1 : 2);
esow.family = family;
esow.sourceMask = eso.source.getBits();
esow.scopeMask = eso.scope.getBits();
ret.assign((const char*)&esow, sizeof(esow)); // NOLINT(cppcoreguidelines-pro-type-cstyle-cast)
int octetsout = ((esow.sourceMask - 1) >> 3) + 1;
ComboAddress src = eso.source.getNetwork();
src.truncate(esow.sourceMask);
if (family == htons(1)) {
ret.append((const char*)&src.sin4.sin_addr.s_addr, octetsout); // NOLINT(cppcoreguidelines-pro-type-cstyle-cast)
}
else {
ret.append((const char*)&src.sin6.sin6_addr.s6_addr, octetsout); // NOLINT(cppcoreguidelines-pro-type-cstyle-cast)
}
return ret;
}
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