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/*
* ZeroTier One - Network Virtualization Everywhere
* Copyright (C) 2011-2015 ZeroTier, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* 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, see <http://www.gnu.org/licenses/>.
*
* --
*
* ZeroTier may be used and distributed under the terms of the GPLv3, which
* are available at: http://www.gnu.org/licenses/gpl-3.0.html
*
* If you would like to embed ZeroTier into a commercial application or
* redistribute it in a modified binary form, please contact ZeroTier Networks
* LLC. Start here: http://www.zerotier.com/
*/
#ifndef ZT_MULTICASTGROUP_HPP
#define ZT_MULTICASTGROUP_HPP
#include <stdint.h>
#include <string>
#include "MAC.hpp"
#include "InetAddress.hpp"
namespace ZeroTier {
/**
* A multicast group composed of a multicast MAC and a 32-bit ADI field
*
* ADI stands for additional distinguishing information. ADI is primarily for
* adding additional information to broadcast (ff:ff:ff:ff:ff:ff) memberships,
* since straight-up broadcast won't scale. Right now it's zero except for
* IPv4 ARP, where it holds the IPv4 address itself to make ARP into a
* selective multicast query that can scale.
*
* In the future we might add some kind of plugin architecture that can add
* ADI for things like mDNS (multicast DNS) to improve the selectivity of
* those protocols.
*
* MulticastGroup behaves as an immutable value object.
*/
class MulticastGroup
{
public:
MulticastGroup()
throw() :
_mac(),
_adi(0)
{
}
MulticastGroup(const MAC &m,uint32_t a)
throw() :
_mac(m),
_adi(a)
{
}
MulticastGroup(const char *s)
{
fromString(s);
}
MulticastGroup(const std::string &s)
{
fromString(s.c_str());
}
/**
* Derive the multicast group used for address resolution (ARP/NDP) for an IP
*
* @param ip IP address (port field is ignored)
* @return Multicat group for ARP/NDP
*/
static inline MulticastGroup deriveMulticastGroupForAddressResolution(const InetAddress &ip)
throw()
{
if (ip.isV4()) {
// IPv4 wants braodcast MACs, so we shove the V4 address itself into
// the Multicast Group ADI field. Making V4 ARP work is basically why
// ADI was added, as well as handling other things that want mindless
// Ethernet broadcast to all.
return MulticastGroup(MAC(0xffffffffffffULL),Utils::ntoh(*((const uint32_t *)ip.rawIpData())));
} else if (ip.isV6()) {
// IPv6 is better designed in this respect. We can compute the IPv6
// multicast address directly from the IP address, and it gives us
// 24 bits of uniqueness. Collisions aren't likely to be common enough
// to care about.
const unsigned char *a = (const unsigned char *)ip.rawIpData();
return MulticastGroup(MAC(0x33,0x33,0xff,a[13],a[14],a[15]),0);
}
return MulticastGroup();
}
/**
* @return Human readable string representing this group (MAC/ADI in hex)
*/
inline std::string toString() const
{
char buf[64];
Utils::snprintf(buf,sizeof(buf),"%.2x%.2x%.2x%.2x%.2x%.2x/%.8lx",(unsigned int)_mac[0],(unsigned int)_mac[1],(unsigned int)_mac[2],(unsigned int)_mac[3],(unsigned int)_mac[4],(unsigned int)_mac[5],(unsigned long)_adi);
return std::string(buf);
}
/**
* Parse a human-readable multicast group
*
* @param s Multicast group in hex MAC/ADI format
*/
inline void fromString(const char *s)
{
char hex[17];
unsigned int hexlen = 0;
while ((*s)&&(*s != '/')&&(hexlen < (sizeof(hex) - 1)))
hex[hexlen++] = *s;
hex[hexlen] = (char)0;
_mac.fromString(hex);
_adi = (*s == '/') ? (uint32_t)Utils::hexStrToULong(s + 1) : (uint32_t)0;
}
/**
* @return Multicast address
*/
inline const MAC &mac() const throw() { return _mac; }
/**
* @return Additional distinguishing information
*/
inline uint32_t adi() const throw() { return _adi; }
inline bool operator==(const MulticastGroup &g) const throw() { return ((_mac == g._mac)&&(_adi == g._adi)); }
inline bool operator!=(const MulticastGroup &g) const throw() { return ((_mac != g._mac)||(_adi != g._adi)); }
inline bool operator<(const MulticastGroup &g) const throw()
{
if (_mac < g._mac)
return true;
else if (_mac == g._mac)
return (_adi < g._adi);
return false;
}
inline bool operator>(const MulticastGroup &g) const throw() { return (g < *this); }
inline bool operator<=(const MulticastGroup &g) const throw() { return !(g < *this); }
inline bool operator>=(const MulticastGroup &g) const throw() { return !(*this < g); }
private:
MAC _mac;
uint32_t _adi;
};
} // namespace ZeroTier
#endif
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