1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
|
/*
* ZeroTier One - Network Virtualization Everywhere
* Copyright (C) 2011-2017 ZeroTier, Inc. https://www.zerotier.com/
*
* 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/>.
*
* --
*
* You can be released from the requirements of the license by purchasing
* a commercial license. Buying such a license is mandatory as soon as you
* develop commercial closed-source software that incorporates or links
* directly against ZeroTier software without disclosing the source code
* of your own application.
*/
#ifndef ZT_MULTICASTGROUP_HPP
#define ZT_MULTICASTGROUP_HPP
#include <stdint.h>
#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() :
_mac(),
_adi(0)
{
}
MulticastGroup(const MAC &m,uint32_t a) :
_mac(m),
_adi(a)
{
}
/**
* 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)
{
if (ip.isV4()) {
// IPv4 wants broadcast 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 Multicast address
*/
inline const MAC &mac() const { return _mac; }
/**
* @return Additional distinguishing information
*/
inline uint32_t adi() const { return _adi; }
inline unsigned long hashCode() const { return (_mac.hashCode() ^ (unsigned long)_adi); }
inline bool operator==(const MulticastGroup &g) const { return ((_mac == g._mac)&&(_adi == g._adi)); }
inline bool operator!=(const MulticastGroup &g) const { return ((_mac != g._mac)||(_adi != g._adi)); }
inline bool operator<(const MulticastGroup &g) const
{
if (_mac < g._mac)
return true;
else if (_mac == g._mac)
return (_adi < g._adi);
return false;
}
inline bool operator>(const MulticastGroup &g) const { return (g < *this); }
inline bool operator<=(const MulticastGroup &g) const { return !(g < *this); }
inline bool operator>=(const MulticastGroup &g) const { return !(*this < g); }
private:
MAC _mac;
uint32_t _adi;
};
} // namespace ZeroTier
#endif
|
