Arjun E K | 57a7fcb | 2020-01-30 06:44:45 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2018-present Open Networking Foundation |
| 3 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | * you may not use this file except in compliance with the License. |
| 5 | * You may obtain a copy of the License at |
| 6 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 7 | * Unless required by applicable law or agreed to in writing, software |
| 8 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 9 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 10 | * See the License for the specific language governing permissions and |
| 11 | * limitations under the License. |
| 12 | */ |
| 13 | |
| 14 | package igmp |
| 15 | |
| 16 | import ( |
| 17 | "encoding/binary" |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 18 | "net" |
| 19 | "time" |
| 20 | |
Arjun E K | 57a7fcb | 2020-01-30 06:44:45 +0000 | [diff] [blame] | 21 | "github.com/google/gopacket" |
| 22 | "github.com/google/gopacket/layers" |
| 23 | bbsim "github.com/opencord/bbsim/internal/bbsim/types" |
| 24 | omci "github.com/opencord/omci-sim" |
| 25 | "github.com/opencord/voltha-protos/v2/go/openolt" |
| 26 | log "github.com/sirupsen/logrus" |
Arjun E K | 57a7fcb | 2020-01-30 06:44:45 +0000 | [diff] [blame] | 27 | ) |
| 28 | |
| 29 | func SendIGMPLeaveGroupV2(ponPortId uint32, onuId uint32, serialNumber string, portNo uint32, macAddress net.HardwareAddr, stream bbsim.Stream) error { |
| 30 | log.WithFields(log.Fields{ |
| 31 | "OnuId": onuId, |
| 32 | "SerialNumber": serialNumber, |
| 33 | "PortNo": portNo, |
| 34 | }).Debugf("Entered SendIGMPLeaveGroupV2") |
| 35 | igmp := createIGMPV2LeaveRequestPacket() |
| 36 | pkt, err := serializeIgmpPacket(ponPortId, onuId, macAddress, igmp) |
| 37 | |
| 38 | if err != nil { |
| 39 | log.WithFields(log.Fields{ |
| 40 | "OnuId": onuId, |
| 41 | "IntfId": ponPortId, |
| 42 | "SerialNumber": serialNumber, |
| 43 | }).Errorf("Seriliazation of igmp packet failed : %s", err) |
| 44 | return err |
| 45 | } |
| 46 | |
| 47 | gemid, err := omci.GetGemPortId(ponPortId, onuId) |
| 48 | if err != nil { |
| 49 | log.WithFields(log.Fields{ |
| 50 | "OnuId": onuId, |
| 51 | "IntfId": ponPortId, |
| 52 | "SerialNumber": serialNumber, |
| 53 | }).Errorf("Can't retrieve GemPortId for IGMP: %s", err) |
| 54 | return err |
| 55 | } |
| 56 | |
| 57 | data := &openolt.Indication_PktInd{ |
| 58 | PktInd: &openolt.PacketIndication{ |
| 59 | IntfType: "pon", |
| 60 | IntfId: ponPortId, |
| 61 | GemportId: uint32(gemid), |
| 62 | Pkt: pkt, |
| 63 | PortNo: portNo, |
| 64 | }, |
| 65 | } |
| 66 | //Sending IGMP packets |
| 67 | if err := stream.Send(&openolt.Indication{Data: data}); err != nil { |
Matteo Scandolo | 583f17d | 2020-02-13 10:35:17 -0800 | [diff] [blame] | 68 | log.WithFields(log.Fields{ |
| 69 | "OnuId": onuId, |
| 70 | "SerialNumber": serialNumber, |
| 71 | "PortNo": portNo, |
| 72 | "IntfId": ponPortId, |
| 73 | "err": err, |
| 74 | }).Error("Fail to send IGMP PktInd indication for ONU") |
Arjun E K | 57a7fcb | 2020-01-30 06:44:45 +0000 | [diff] [blame] | 75 | return err |
| 76 | } |
| 77 | return nil |
| 78 | } |
| 79 | |
| 80 | func SendIGMPMembershipReportV2(ponPortId uint32, onuId uint32, serialNumber string, portNo uint32, macAddress net.HardwareAddr, stream bbsim.Stream) error { |
| 81 | log.WithFields(log.Fields{ |
| 82 | "OnuId": onuId, |
| 83 | "SerialNumber": serialNumber, |
| 84 | "PortNo": portNo, |
| 85 | }).Debugf("Entered SendIGMPMembershipReportV2") |
| 86 | igmp := createIGMPV2MembershipReportPacket() |
| 87 | pkt, err := serializeIgmpPacket(ponPortId, onuId, macAddress, igmp) |
| 88 | |
| 89 | if err != nil { |
| 90 | log.WithFields(log.Fields{ |
| 91 | "OnuId": onuId, |
| 92 | "IntfId": ponPortId, |
| 93 | "SerialNumber": serialNumber, |
| 94 | }).Errorf("Seriliazation of igmp packet failed : %s", err) |
| 95 | return err |
| 96 | } |
| 97 | |
| 98 | gemid, err := omci.GetGemPortId(ponPortId, onuId) |
| 99 | if err != nil { |
| 100 | log.WithFields(log.Fields{ |
| 101 | "OnuId": onuId, |
| 102 | "IntfId": ponPortId, |
| 103 | "SerialNumber": serialNumber, |
| 104 | }).Errorf("Can't retrieve GemPortId for IGMP: %s", err) |
| 105 | return err |
| 106 | } |
| 107 | |
| 108 | data := &openolt.Indication_PktInd{ |
| 109 | PktInd: &openolt.PacketIndication{ |
| 110 | IntfType: "pon", |
| 111 | IntfId: ponPortId, |
| 112 | GemportId: uint32(gemid), |
| 113 | Pkt: pkt, |
| 114 | PortNo: portNo, |
| 115 | }, |
| 116 | } |
| 117 | //Sending IGMP packets |
| 118 | if err := stream.Send(&openolt.Indication{Data: data}); err != nil { |
Matteo Scandolo | 583f17d | 2020-02-13 10:35:17 -0800 | [diff] [blame] | 119 | log.WithFields(log.Fields{ |
| 120 | "OnuId": onuId, |
| 121 | "SerialNumber": serialNumber, |
| 122 | "PortNo": portNo, |
| 123 | "IntfId": ponPortId, |
| 124 | "err": err, |
| 125 | }).Errorf("Fail to send IGMP PktInd indication") |
Arjun E K | 57a7fcb | 2020-01-30 06:44:45 +0000 | [diff] [blame] | 126 | return err |
| 127 | } |
| 128 | return nil |
| 129 | } |
| 130 | |
Arjun E K | dd443f0 | 2020-02-07 15:24:01 +0000 | [diff] [blame] | 131 | func SendIGMPMembershipReportV3(ponPortId uint32, onuId uint32, serialNumber string, portNo uint32, macAddress net.HardwareAddr, stream bbsim.Stream) error { |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 132 | log.WithFields(log.Fields{ |
| 133 | "OnuId": onuId, |
| 134 | "SerialNumber": serialNumber, |
| 135 | "PortNo": portNo, |
| 136 | }).Debugf("Entered SendIGMPMembershipReportV3") |
| 137 | igmp := createIGMPV3MembershipReportPacket() |
| 138 | pkt, err := serializeIgmpPacket(ponPortId, onuId, macAddress, igmp) |
Arjun E K | dd443f0 | 2020-02-07 15:24:01 +0000 | [diff] [blame] | 139 | |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 140 | if err != nil { |
| 141 | log.WithFields(log.Fields{ |
| 142 | "OnuId": onuId, |
| 143 | "IntfId": ponPortId, |
| 144 | "SerialNumber": serialNumber, |
| 145 | }).Errorf("Seriliazation of igmp packet failed : %s", err) |
| 146 | return err |
| 147 | } |
Arjun E K | dd443f0 | 2020-02-07 15:24:01 +0000 | [diff] [blame] | 148 | |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 149 | gemid, err := omci.GetGemPortId(ponPortId, onuId) |
| 150 | if err != nil { |
| 151 | log.WithFields(log.Fields{ |
| 152 | "OnuId": onuId, |
| 153 | "IntfId": ponPortId, |
| 154 | "SerialNumber": serialNumber, |
| 155 | }).Errorf("Can't retrieve GemPortId for IGMP: %s", err) |
| 156 | return err |
| 157 | } |
Arjun E K | dd443f0 | 2020-02-07 15:24:01 +0000 | [diff] [blame] | 158 | |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 159 | data := &openolt.Indication_PktInd{ |
| 160 | PktInd: &openolt.PacketIndication{ |
| 161 | IntfType: "pon", |
| 162 | IntfId: ponPortId, |
| 163 | GemportId: uint32(gemid), |
| 164 | Pkt: pkt, |
| 165 | PortNo: portNo, |
| 166 | }, |
| 167 | } |
| 168 | //Sending IGMP packets |
| 169 | if err := stream.Send(&openolt.Indication{Data: data}); err != nil { |
| 170 | log.Errorf("Fail to send IGMP PktInd indication for ONU: %s, IntfId: %s, SerialNumber: %s, error: %v", onuId, ponPortId, serialNumber, err) |
| 171 | return err |
| 172 | } |
| 173 | return nil |
Arjun E K | dd443f0 | 2020-02-07 15:24:01 +0000 | [diff] [blame] | 174 | } |
| 175 | |
| 176 | func createIGMPV3MembershipReportPacket() IGMP { |
| 177 | |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 178 | groupRecord1 := IGMPv3GroupRecord{ |
| 179 | Type: IGMPv3GroupRecordType(IGMPIsIn), |
| 180 | AuxDataLen: 0, // this should always be 0 as per IGMPv3 spec. |
| 181 | NumberOfSources: 3, |
| 182 | MulticastAddress: net.IPv4(224, 0, 0, 22), |
| 183 | SourceAddresses: []net.IP{net.IPv4(15, 14, 20, 24), net.IPv4(15, 14, 20, 26), net.IPv4(15, 14, 20, 25)}, |
| 184 | AuxData: 0, // NOT USED |
| 185 | } |
Arjun E K | dd443f0 | 2020-02-07 15:24:01 +0000 | [diff] [blame] | 186 | |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 187 | groupRecord2 := IGMPv3GroupRecord{ |
| 188 | Type: IGMPv3GroupRecordType(IGMPIsIn), |
| 189 | AuxDataLen: 0, // this should always be 0 as per IGMPv3 spec. |
| 190 | NumberOfSources: 2, |
| 191 | MulticastAddress: net.IPv4(224, 0, 0, 25), |
| 192 | SourceAddresses: []net.IP{net.IPv4(15, 14, 20, 30), net.IPv4(15, 14, 20, 31)}, |
| 193 | AuxData: 0, // NOT USED |
| 194 | } |
Arjun E K | dd443f0 | 2020-02-07 15:24:01 +0000 | [diff] [blame] | 195 | |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 196 | igmpDefault := IGMP{ |
| 197 | Type: 0x22, //IGMPV3 Membership Report |
| 198 | MaxResponseTime: time.Duration(1), |
| 199 | Checksum: 0, |
| 200 | GroupAddress: net.IPv4(224, 0, 0, 22), |
| 201 | SupressRouterProcessing: false, |
| 202 | RobustnessValue: 0, |
| 203 | IntervalTime: time.Duration(1), |
| 204 | SourceAddresses: []net.IP{net.IPv4(224, 0, 0, 24)}, |
| 205 | NumberOfGroupRecords: 2, |
| 206 | NumberOfSources: 1, |
| 207 | GroupRecords: []IGMPv3GroupRecord{groupRecord1, groupRecord2}, |
| 208 | Version: 3, |
| 209 | } |
Arjun E K | dd443f0 | 2020-02-07 15:24:01 +0000 | [diff] [blame] | 210 | |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 211 | return igmpDefault |
Arjun E K | dd443f0 | 2020-02-07 15:24:01 +0000 | [diff] [blame] | 212 | } |
| 213 | |
Arjun E K | 57a7fcb | 2020-01-30 06:44:45 +0000 | [diff] [blame] | 214 | //func serializeIgmpPacket(intfId uint32, onuId uint32, srcMac net.HardwareAddr, igmp *layers.IGMP) ([]byte, error) { |
| 215 | func createIGMPV2MembershipReportPacket() IGMP { |
| 216 | return IGMP{ |
| 217 | Type: 0x16, //IGMPV2 Membership Report |
| 218 | MaxResponseTime: time.Duration(1), |
| 219 | Checksum: 0, |
| 220 | GroupAddress: net.IPv4(224, 0, 0, 22), |
| 221 | Version: 2, |
| 222 | } |
| 223 | } |
| 224 | |
| 225 | func createIGMPV2LeaveRequestPacket() IGMP { |
| 226 | return IGMP{ |
| 227 | Type: 0x17, //IGMPV2 Leave Group |
| 228 | MaxResponseTime: time.Duration(1), |
| 229 | Checksum: 0, |
| 230 | GroupAddress: net.IPv4(224, 0, 0, 22), |
| 231 | Version: 2, |
| 232 | } |
| 233 | } |
| 234 | |
| 235 | func serializeIgmpPacket(intfId uint32, onuId uint32, srcMac net.HardwareAddr, igmp IGMP) ([]byte, error) { |
| 236 | buffer := gopacket.NewSerializeBuffer() |
| 237 | options := gopacket.SerializeOptions{ |
| 238 | ComputeChecksums: true, |
| 239 | FixLengths: true, |
| 240 | } |
| 241 | |
| 242 | ethernetLayer := &layers.Ethernet{ |
| 243 | SrcMAC: srcMac, |
| 244 | DstMAC: net.HardwareAddr{0xff, 0xff, 0xff, 0xff, 0xff, 0xff}, |
| 245 | EthernetType: layers.EthernetTypeIPv4, |
| 246 | } |
| 247 | |
| 248 | ipLayer := &layers.IPv4{ |
| 249 | Version: 4, |
| 250 | TOS: 0x10, |
| 251 | Id: 0, |
| 252 | TTL: 128, |
| 253 | SrcIP: []byte{0, 0, 0, 0}, |
| 254 | DstIP: []byte{224, 0, 0, 22}, |
| 255 | Protocol: layers.IPProtocolIGMP, |
| 256 | Options: []layers.IPv4Option{{OptionType: 148, OptionLength: 4, OptionData: make([]byte, 0)}}, //Adding router alert option |
| 257 | } |
| 258 | |
| 259 | if err := gopacket.SerializeLayers(buffer, options, ethernetLayer, ipLayer, igmp); err != nil { |
| 260 | return nil, err |
| 261 | } |
| 262 | |
| 263 | return buffer.Bytes(), nil |
| 264 | } |
| 265 | |
| 266 | //-----------------------------------------***********************--------------------------------- |
| 267 | // BaseLayer is a convenience struct which implements the LayerData and |
| 268 | // LayerPayload functions of the Layer interface. |
| 269 | type BaseLayer struct { |
| 270 | // Contents is the set of bytes that make up this layer. IE: for an |
| 271 | // Ethernet packet, this would be the set of bytes making up the |
| 272 | // Ethernet frame. |
| 273 | Contents []byte |
| 274 | // Payload is the set of bytes contained by (but not part of) this |
| 275 | // Layer. Again, to take Ethernet as an example, this would be the |
| 276 | // set of bytes encapsulated by the Ethernet protocol. |
| 277 | Payload []byte |
| 278 | } |
| 279 | |
| 280 | type IGMPType uint8 |
| 281 | |
| 282 | type IGMP struct { |
| 283 | BaseLayer |
| 284 | Type IGMPType |
| 285 | MaxResponseTime time.Duration |
| 286 | Checksum uint16 |
| 287 | GroupAddress net.IP |
| 288 | SupressRouterProcessing bool |
| 289 | RobustnessValue uint8 |
| 290 | IntervalTime time.Duration |
| 291 | SourceAddresses []net.IP |
| 292 | NumberOfGroupRecords uint16 |
| 293 | NumberOfSources uint16 |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 294 | GroupRecords []IGMPv3GroupRecord |
Arjun E K | 57a7fcb | 2020-01-30 06:44:45 +0000 | [diff] [blame] | 295 | Version uint8 // IGMP protocol version |
| 296 | } |
| 297 | |
Arjun E K | dd443f0 | 2020-02-07 15:24:01 +0000 | [diff] [blame] | 298 | // IGMPv3GroupRecord stores individual group records for a V3 Membership Report message. |
| 299 | type IGMPv3GroupRecord struct { |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 300 | Type IGMPv3GroupRecordType |
| 301 | AuxDataLen uint8 // this should always be 0 as per IGMPv3 spec. |
| 302 | NumberOfSources uint16 |
| 303 | MulticastAddress net.IP |
| 304 | SourceAddresses []net.IP |
| 305 | AuxData uint32 // NOT USED |
Arjun E K | dd443f0 | 2020-02-07 15:24:01 +0000 | [diff] [blame] | 306 | } |
| 307 | |
| 308 | type IGMPv3GroupRecordType uint8 |
| 309 | |
| 310 | const ( |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 311 | IGMPIsIn IGMPv3GroupRecordType = 0x01 // Type MODE_IS_INCLUDE, source addresses x |
| 312 | IGMPIsEx IGMPv3GroupRecordType = 0x02 // Type MODE_IS_EXCLUDE, source addresses x |
| 313 | IGMPToIn IGMPv3GroupRecordType = 0x03 // Type CHANGE_TO_INCLUDE_MODE, source addresses x |
| 314 | IGMPToEx IGMPv3GroupRecordType = 0x04 // Type CHANGE_TO_EXCLUDE_MODE, source addresses x |
| 315 | IGMPAllow IGMPv3GroupRecordType = 0x05 // Type ALLOW_NEW_SOURCES, source addresses x |
| 316 | IGMPBlock IGMPv3GroupRecordType = 0x06 // Type BLOCK_OLD_SOURCES, source addresses x |
Arjun E K | dd443f0 | 2020-02-07 15:24:01 +0000 | [diff] [blame] | 317 | ) |
| 318 | |
| 319 | func (i IGMPv3GroupRecordType) String() string { |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 320 | switch i { |
| 321 | case IGMPIsIn: |
| 322 | return "MODE_IS_INCLUDE" |
| 323 | case IGMPIsEx: |
| 324 | return "MODE_IS_EXCLUDE" |
| 325 | case IGMPToIn: |
| 326 | return "CHANGE_TO_INCLUDE_MODE" |
| 327 | case IGMPToEx: |
| 328 | return "CHANGE_TO_EXCLUDE_MODE" |
| 329 | case IGMPAllow: |
| 330 | return "ALLOW_NEW_SOURCES" |
| 331 | case IGMPBlock: |
| 332 | return "BLOCK_OLD_SOURCES" |
| 333 | default: |
| 334 | return "" |
| 335 | } |
Arjun E K | dd443f0 | 2020-02-07 15:24:01 +0000 | [diff] [blame] | 336 | } |
| 337 | |
Arjun E K | 57a7fcb | 2020-01-30 06:44:45 +0000 | [diff] [blame] | 338 | // SerializeTo writes the serialized form of this layer into the |
| 339 | // SerializationBuffer, implementing gopacket.SerializableLayer. |
| 340 | // See the docs for gopacket.SerializableLayer for more info. |
Arjun E K | 57a7fcb | 2020-01-30 06:44:45 +0000 | [diff] [blame] | 341 | func (igmp IGMP) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error { |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 342 | log.Debugf("Serializing IGMP Packet") |
Arjun E K | 57a7fcb | 2020-01-30 06:44:45 +0000 | [diff] [blame] | 343 | data, err := b.PrependBytes(8915) |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 344 | if err != nil { |
| 345 | return err |
| 346 | } |
| 347 | if igmp.Version == 2 { |
| 348 | data[0] = byte(igmp.Type) |
| 349 | data[1] = byte(igmp.MaxResponseTime) |
| 350 | data[2] = 0 |
| 351 | data[3] = 0 |
| 352 | copy(data[4:8], igmp.GroupAddress.To4()) |
| 353 | if opts.ComputeChecksums { |
| 354 | igmp.Checksum = tcpipChecksum(data, 0) |
| 355 | binary.BigEndian.PutUint16(data[2:4], igmp.Checksum) |
| 356 | } |
| 357 | } else if igmp.Version == 3 { |
Arjun E K | 57a7fcb | 2020-01-30 06:44:45 +0000 | [diff] [blame] | 358 | |
Anand S Katti | 0954135 | 2020-01-29 15:54:01 +0530 | [diff] [blame^] | 359 | data[0] = byte(igmp.Type) |
| 360 | data[1] = 0 |
| 361 | data[2] = 0 |
| 362 | data[3] = 0 |
| 363 | data[4] = 0 |
| 364 | data[5] = 0 |
| 365 | binary.BigEndian.PutUint16(data[6:8], igmp.NumberOfGroupRecords) |
| 366 | j := 8 |
| 367 | for i := uint16(0); i < igmp.NumberOfGroupRecords; i++ { |
| 368 | data[j] = byte(igmp.GroupRecords[i].Type) |
| 369 | data[j+1] = byte(0) |
| 370 | binary.BigEndian.PutUint16(data[j+2:j+4], igmp.GroupRecords[i].NumberOfSources) |
| 371 | copy(data[j+4:j+8], igmp.GroupRecords[i].MulticastAddress.To4()) |
| 372 | j = j + 8 |
| 373 | for m := uint16(0); m < igmp.GroupRecords[i].NumberOfSources; m++ { |
| 374 | copy(data[j:(j+4)], igmp.GroupRecords[i].SourceAddresses[m].To4()) |
| 375 | j = j + 4 |
| 376 | } |
| 377 | } |
| 378 | if opts.ComputeChecksums { |
| 379 | igmp.Checksum = tcpipChecksum(data, 0) |
| 380 | binary.BigEndian.PutUint16(data[2:4], igmp.Checksum) |
| 381 | } |
| 382 | } |
| 383 | return nil |
Arjun E K | 57a7fcb | 2020-01-30 06:44:45 +0000 | [diff] [blame] | 384 | } |
| 385 | |
| 386 | // Calculate the TCP/IP checksum defined in rfc1071. The passed-in csum is any |
| 387 | // initial checksum data that's already been computed. |
| 388 | func tcpipChecksum(data []byte, csum uint32) uint16 { |
| 389 | // to handle odd lengths, we loop to length - 1, incrementing by 2, then |
| 390 | // handle the last byte specifically by checking against the original |
| 391 | // length. |
| 392 | length := len(data) - 1 |
| 393 | for i := 0; i < length; i += 2 { |
| 394 | // For our test packet, doing this manually is about 25% faster |
| 395 | // (740 ns vs. 1000ns) than doing it by calling binary.BigEndian.Uint16. |
| 396 | csum += uint32(data[i]) << 8 |
| 397 | csum += uint32(data[i+1]) |
| 398 | } |
| 399 | if len(data)%2 == 1 { |
| 400 | csum += uint32(data[length]) << 8 |
| 401 | } |
| 402 | for csum > 0xffff { |
| 403 | csum = (csum >> 16) + (csum & 0xffff) |
| 404 | } |
| 405 | return ^uint16(csum) |
| 406 | } |
| 407 | |
| 408 | func (IGMP) LayerType() gopacket.LayerType { return layers.LayerTypeIGMP } |