| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | package l2topology |
| 4 | |
| 5 | import ( |
| 6 | "fmt" |
| 7 | "net/netip" |
| 8 | "sort" |
| 9 | "strconv" |
| 10 | ) |
| 11 | |
| 12 | var ( |
| 13 | pointToPointMaskIPv4 = netip.MustParseAddr("255.255.255.252") |
| 14 | pointToPointMaskIPv6 = netip.MustParseAddr("ffff:ffff:ffff:ffff:ffff:ffff:ffff:fffe") |
| 15 | loopbackMaskIPv4 = netip.MustParseAddr("255.255.255.255") |
| 16 | loopbackMaskIPv6 = netip.MustParseAddr("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff") |
| 17 | loopbackAddrIPv4 = netip.MustParseAddr("127.0.0.1") |
| 18 | ) |
| 19 | |
| 20 | // SubNetwork mirrors Enlinkd SubNetwork behavior for node/IP membership. |
| 21 | type SubNetwork struct { |
| 22 | network netip.Addr |
| 23 | netmask netip.Addr |
| 24 | nodeInterfaceMap map[int]map[netip.Addr]struct{} |
| 25 | } |
| 26 | |
| 27 | // NewSubNetwork creates a subnet from one managed IP interface. |
| 28 | func NewSubNetwork(nodeID int, ip, netmask netip.Addr) (*SubNetwork, error) { |
| 29 | if nodeID <= 0 { |
| 30 | return nil, fmt.Errorf("node id is required") |
| 31 | } |
| 32 | if !ip.IsValid() { |
| 33 | return nil, fmt.Errorf("ip is required") |
| 34 | } |
| 35 | if !netmask.IsValid() { |
| 36 | return nil, fmt.Errorf("netmask is required") |
| 37 | } |
| 38 | network, ok := NetworkAddress(ip, netmask) |
| 39 | if !ok { |
| 40 | return nil, fmt.Errorf("cannot build network from ip %q and netmask %q", ip, netmask) |
| 41 | } |
| 42 | s := &SubNetwork{ |
| 43 | network: network, |
| 44 | netmask: netmask, |
| 45 | nodeInterfaceMap: map[int]map[netip.Addr]struct{}{}, |
| 46 | } |
| 47 | s.nodeInterfaceMap[nodeID] = map[netip.Addr]struct{}{ip.Unmap(): {}} |
| 48 | return s, nil |
| 49 | } |
| 50 | |
| 51 | // Network returns the network address. |
| 52 | func (s *SubNetwork) Network() netip.Addr { |
| 53 | if s == nil { |
| 54 | return netip.Addr{} |
| 55 | } |
| 56 | return s.network |
| 57 | } |
| 58 | |
| 59 | // Netmask returns the subnet mask. |
| 60 | func (s *SubNetwork) Netmask() netip.Addr { |
| 61 | if s == nil { |
| 62 | return netip.Addr{} |
| 63 | } |
| 64 | return s.netmask |
| 65 | } |
| 66 | |
| 67 | // CIDR returns network/prefix format. |
| 68 | func (s *SubNetwork) CIDR() string { |
| 69 | if s == nil || !s.network.IsValid() || !s.netmask.IsValid() { |
| 70 | return "" |
| 71 | } |
| 72 | prefix, err := MaskToCIDRPrefix(s.netmask) |
| 73 | if err != nil { |
| 74 | return "" |
| 75 | } |
| 76 | return s.network.String() + "/" + strconv.Itoa(prefix) |
| 77 | } |
| 78 | |
| 79 | // NetworkPrefix returns the CIDR prefix for the mask. |
| 80 | func (s *SubNetwork) NetworkPrefix() int { |
| 81 | if s == nil { |
| 82 | return 0 |
| 83 | } |
| 84 | prefix, err := MaskToCIDRPrefix(s.netmask) |
| 85 | if err != nil { |
| 86 | return 0 |
| 87 | } |
| 88 | return prefix |
| 89 | } |
| 90 | |
| 91 | // IsIPv4Subnetwork reports if the subnet uses IPv4. |
| 92 | func (s *SubNetwork) IsIPv4Subnetwork() bool { |
| 93 | return s != nil && s.network.IsValid() && s.network.Is4() |
| 94 | } |
| 95 | |
| 96 | // NodeIDs returns sorted node IDs in the subnet. |
| 97 | func (s *SubNetwork) NodeIDs() []int { |
| 98 | if s == nil || len(s.nodeInterfaceMap) == 0 { |
| 99 | return nil |
| 100 | } |
| 101 | ids := make([]int, 0, len(s.nodeInterfaceMap)) |
| 102 | for nodeID := range s.nodeInterfaceMap { |
| 103 | ids = append(ids, nodeID) |
| 104 | } |
| 105 | sort.Ints(ids) |
| 106 | return ids |
| 107 | } |
| 108 | |
| 109 | // Add adds one node/IP membership if the address is in range. |
| 110 | func (s *SubNetwork) Add(nodeID int, ip netip.Addr) bool { |
| 111 | if s == nil || nodeID <= 0 || !ip.IsValid() || !s.IsInRange(ip) { |
| 112 | return false |
| 113 | } |
| 114 | ip = ip.Unmap() |
| 115 | if _, ok := s.nodeInterfaceMap[nodeID]; !ok { |
| 116 | s.nodeInterfaceMap[nodeID] = map[netip.Addr]struct{}{} |
| 117 | } |
| 118 | if _, exists := s.nodeInterfaceMap[nodeID][ip]; exists { |
| 119 | return false |
| 120 | } |
| 121 | s.nodeInterfaceMap[nodeID][ip] = struct{}{} |
| 122 | return true |
| 123 | } |
| 124 | |
| 125 | // Remove removes one node/IP membership. |
| 126 | func (s *SubNetwork) Remove(nodeID int, ip netip.Addr) bool { |
| 127 | if s == nil || nodeID <= 0 || !ip.IsValid() { |
| 128 | return false |
| 129 | } |
| 130 | ip = ip.Unmap() |
| 131 | ips, ok := s.nodeInterfaceMap[nodeID] |
| 132 | if !ok { |
| 133 | return false |
| 134 | } |
| 135 | if _, exists := ips[ip]; !exists { |
| 136 | return false |
| 137 | } |
| 138 | delete(ips, ip) |
| 139 | if len(ips) == 0 { |
| 140 | delete(s.nodeInterfaceMap, nodeID) |
| 141 | } |
| 142 | return true |
| 143 | } |
| 144 | |
| 145 | // IsInRange reports if ip belongs to this subnet. |
| 146 | func (s *SubNetwork) IsInRange(ip netip.Addr) bool { |
| 147 | if s == nil || !ip.IsValid() || !s.network.IsValid() || !s.netmask.IsValid() { |
| 148 | return false |
| 149 | } |
| 150 | return InSameNetwork(ip.Unmap(), s.network, s.netmask) |
| 151 | } |
| 152 | |
| 153 | // HasDuplicatedAddress reports true when the same address exists under multiple entries. |
| 154 | func (s *SubNetwork) HasDuplicatedAddress() bool { |
| 155 | if s == nil { |
| 156 | return false |
| 157 | } |
| 158 | seen := make(map[netip.Addr]struct{}) |
| 159 | for _, addresses := range s.nodeInterfaceMap { |
| 160 | for addr := range addresses { |
| 161 | if _, ok := seen[addr]; ok { |
| 162 | return true |
| 163 | } |
| 164 | seen[addr] = struct{}{} |
| 165 | } |
| 166 | } |
| 167 | return false |
| 168 | } |
| 169 | |
| 170 | func (s *SubNetwork) clone() *SubNetwork { |
| 171 | if s == nil { |
| 172 | return nil |
| 173 | } |
| 174 | out := &SubNetwork{ |
| 175 | network: s.network, |
| 176 | netmask: s.netmask, |
| 177 | nodeInterfaceMap: make(map[int]map[netip.Addr]struct{}, len(s.nodeInterfaceMap)), |
| 178 | } |
| 179 | for nodeID, ips := range s.nodeInterfaceMap { |
| 180 | copySet := make(map[netip.Addr]struct{}, len(ips)) |
| 181 | for ip := range ips { |
| 182 | copySet[ip] = struct{}{} |
| 183 | } |
| 184 | out.nodeInterfaceMap[nodeID] = copySet |
| 185 | } |
| 186 | return out |
| 187 | } |
| 188 | |
| 189 | func (s *SubNetwork) key() string { |
| 190 | if s == nil { |
| 191 | return "" |
| 192 | } |
| 193 | return subnetKey(s.network, s.netmask) |
| 194 | } |
| 195 | |
| 196 | func subnetKey(network, netmask netip.Addr) string { |
| 197 | if !network.IsValid() || !netmask.IsValid() { |
| 198 | return "" |
| 199 | } |
| 200 | // Unmap IPv4-mapped IPv6 addresses so that ::ffff:10.0.0.0 and 10.0.0.0 |
| 201 | // produce the same key. |
| 202 | network = network.Unmap() |
| 203 | netmask = netmask.Unmap() |
| 204 | return network.String() + keySep + netmask.String() |
| 205 | } |
| 206 | |
| 207 | func sortedSubnetworkKeys(subnets map[string]*SubNetwork) []string { |
| 208 | keys := make([]string, 0, len(subnets)) |
| 209 | for key := range subnets { |
| 210 | keys = append(keys, key) |
| 211 | } |
| 212 | sort.Strings(keys) |
| 213 | return keys |
| 214 | } |
| 215 | |
| 216 | func compareAddr(a, b netip.Addr) int { |
| 217 | ab := addrBytes(a) |
| 218 | bb := addrBytes(b) |
| 219 | if len(ab) != len(bb) { |
| 220 | if len(ab) < len(bb) { |
| 221 | return -1 |
| 222 | } |
| 223 | return 1 |
| 224 | } |
| 225 | for i := range ab { |
| 226 | if ab[i] < bb[i] { |
| 227 | return -1 |
| 228 | } |
| 229 | if ab[i] > bb[i] { |
| 230 | return 1 |
| 231 | } |
| 232 | } |
| 233 | return 0 |
| 234 | } |
| 235 | |
| 236 | // IsPointToPointMask ports InetAddressUtils.isPointToPointMask(). |
| 237 | func IsPointToPointMask(mask netip.Addr) bool { |
| 238 | mask = mask.Unmap() |
| 239 | return mask == pointToPointMaskIPv4 || mask == pointToPointMaskIPv6 |
| 240 | } |
| 241 | |
| 242 | // IsLoopbackMask ports InetAddressUtils.isLoopbackMask(). |
| 243 | func IsLoopbackMask(mask netip.Addr) bool { |
| 244 | mask = mask.Unmap() |
| 245 | return mask == loopbackMaskIPv4 || mask == loopbackMaskIPv6 |
| 246 | } |
| 247 | |
| 248 | // InSameNetwork ports InetAddressUtils.inSameNetwork(). |
| 249 | func InSameNetwork(addr1, addr2, mask netip.Addr) bool { |
| 250 | addr1 = addr1.Unmap() |
| 251 | addr2 = addr2.Unmap() |
| 252 | mask = mask.Unmap() |
| 253 | if !addr1.IsValid() || !addr2.IsValid() || !mask.IsValid() { |
| 254 | return false |
| 255 | } |
| 256 | if addr1.Is4() != addr2.Is4() || addr1.Is4() != mask.Is4() { |
| 257 | return false |
| 258 | } |
| 259 | |
| 260 | ab := addrBytes(addr1) |
| 261 | bb := addrBytes(addr2) |
| 262 | mb := addrBytes(mask) |
| 263 | if len(ab) != len(bb) || len(ab) != len(mb) { |
| 264 | return false |
| 265 | } |
| 266 | for i := range ab { |
| 267 | if (ab[i] & mb[i]) != (bb[i] & mb[i]) { |
| 268 | return false |
| 269 | } |
| 270 | } |
| 271 | return true |
| 272 | } |
| 273 | |
| 274 | // NetworkAddress returns ip&mask for matching IP families. |
| 275 | func NetworkAddress(ip, mask netip.Addr) (netip.Addr, bool) { |
| 276 | ip = ip.Unmap() |
| 277 | mask = mask.Unmap() |
| 278 | if !ip.IsValid() || !mask.IsValid() || ip.Is4() != mask.Is4() { |
| 279 | return netip.Addr{}, false |
| 280 | } |
| 281 | ib := addrBytes(ip) |
| 282 | mb := addrBytes(mask) |
| 283 | if len(ib) != len(mb) { |
| 284 | return netip.Addr{}, false |
| 285 | } |
| 286 | out := make([]byte, len(ib)) |
| 287 | for i := range ib { |
| 288 | out[i] = ib[i] & mb[i] |
| 289 | } |
| 290 | addr, ok := netip.AddrFromSlice(out) |
| 291 | if !ok { |
| 292 | return netip.Addr{}, false |
| 293 | } |
| 294 | return addr.Unmap(), true |
| 295 | } |
| 296 | |
| 297 | // MaskToCIDRPrefix ports InetAddressUtils.convertInetAddressMaskToCidr(). |
| 298 | func MaskToCIDRPrefix(mask netip.Addr) (int, error) { |
| 299 | mask = mask.Unmap() |
| 300 | if !mask.IsValid() { |
| 301 | return 0, fmt.Errorf("invalid mask") |
| 302 | } |
| 303 | foundZero := false |
| 304 | cidr := 0 |
| 305 | for _, value := range addrBytes(mask) { |
| 306 | k := int(value) |
| 307 | if foundZero && k != 0 { |
| 308 | return 0, fmt.Errorf("invalid mask %q", mask) |
| 309 | } |
| 310 | switch k { |
| 311 | case 255: |
| 312 | cidr += 8 |
| 313 | case 254: |
| 314 | cidr += 7 |
| 315 | foundZero = true |
| 316 | case 252: |
| 317 | cidr += 6 |
| 318 | foundZero = true |
| 319 | case 248: |
| 320 | cidr += 5 |
| 321 | foundZero = true |
| 322 | case 240: |
| 323 | cidr += 4 |
| 324 | foundZero = true |
| 325 | case 224: |
| 326 | cidr += 3 |
| 327 | foundZero = true |
| 328 | case 192: |
| 329 | cidr += 2 |
| 330 | foundZero = true |
| 331 | case 128: |
| 332 | cidr += 1 |
| 333 | foundZero = true |
| 334 | case 0: |
| 335 | foundZero = true |
| 336 | default: |
| 337 | return 0, fmt.Errorf("invalid mask %q", mask) |
| 338 | } |
| 339 | } |
| 340 | return cidr, nil |
| 341 | } |
| 342 | |
| 343 | func addrBytes(addr netip.Addr) []byte { |
| 344 | if !addr.IsValid() { |
| 345 | return nil |
| 346 | } |
| 347 | if addr.Is4() { |
| 348 | a := addr.As4() |
| 349 | return a[:] |
| 350 | } |
| 351 | a := addr.As16() |
| 352 | return a[:] |
| 353 | } |