Package v2 provides simple and painless handling of GTPv2-C protocol in pure Golang.
Working examples are available in example directory, which might be the better instruction for developers.
Dial opens a connection between the specified peer by confirming the peer is alive by Echo Request/Response exchange. If you don't need Echo, see Server section.
// Note that the conn is not bound to raddr. to let a Conn to be able to communicate with multiple peers.
// Interface type is required here to let Conn know which is the local interface type.
conn, err := gtpv2.Dial(ctx, laddr, raddr, gtpv2.IFTypeS11MMEGTPC, 0)
if err != nil {
// ...
}Retrieve Conn with NewConn, and ListenAndServe to start listening.
// Interface type is required here to let Conn know which is the local interface type.
srvConn := gtpv2.NewConn(srvAddr, gtpv2.IFTypeS11MMEGTPC, 0)
if err := srvConn.ListenAndServe(ctx); err != nil {
// ...
}Prepare functions that comform to HandlerFunc, and register them to Conn with AddHandler. This should be done as soon as you get Conn not to miss the incoming messages.
HandlerFunc is to handle the incoming messages by message type. See example for how it is like.
Also consider using AddHandlers when you have many HandlerFuncs.
// write what you expect to do on receiving a message. Handlers should be added per message type.
// by default, Echo Request/Response and Version Not Supported Indication is handled automatically.
conn.AddHandler(
// first param is the type of message. give number in uint8 or use gtpgtpv2.MsgTypeXXX.
messages.MsgTypeCreateSessionResponse,
// second param is the HandlerFunc to describe how you handle the message coming from peer.
func(c *gtpv2.Conn, senderAddr net.Addr, msg messages.Message) error {
// Do what you want with CreateSessionResponse message here.
// see examples directly for functional examples
},
)With Conn, you can create, modify, delete GTPv2-C sessions and bearers with the built-in methods.
CreateSession creates a Session, while storing values given as IEs and creating a default bearer.
In the following call, for example, IMSI and TEID for S1-U eNB is stored in the created Session.
session, err := c.CreateSession(
// put IEs required for your implementation here.
// it is easier to use constructors in ie package.
ie.NewIMSI("123451234567890"),
// or, you can use ie.New() to create an IE without type-specific constructor.
// put the type of IE, flags/instance, and payload as the parameters.
ie.New(ie.ExtendedTraceInformation, 0x00, []byte{0xde, 0xad, 0xbe, 0xef}),
// to set the instance to IE created with message-specific constructor, WithInstance()
// may be your help.
ie.NewIMSI("123451234567890").WithInstance(1), // no one wants to set instance to IMSI, though.
// don't forget to contain the Sender F-TEID, as it is used to distinguish the incoming
// message by Conn.
//
// to be secure, TEID should be generated with random values, without conflicts in a Conn.
// to achieve that, gtpv2 provides NewFTEID() which returns F-TEID in *ie.IE.
s11Conn.NewFTEID(gtpv2.IFTypeS11MMEGTPC, mmeIP, ""),
)
if err != nil {
// ...
}DeleteSession and ModifyBearer methods are provided to send each message as easy as possible.
Unlike CreateSession, they don't manipulate the Session information automatically.
See v1/README.md.
The following Messages marked with "Yes" are currently available with their own useful constructors.
Even there are some missing Messages, you can create any kind of Message by using messages.NewGeneric().
| ID | Name | Supported |
|---|---|---|
| 0 | (Spare/Reserved) | - |
| 1 | Echo Request | Yes |
| 2 | Echo Response | Yes |
| 3 | Version Not Supported Indication | Yes |
| 4-16 | (Spare/Reserved) | - |
| 17-24 | (Spare/Reserved) | - |
| 25-31 | (Spare/Reserved) | - |
| 32 | Create Session Request | Yes |
| 33 | Create Session Response | Yes |
| 34 | Modify Bearer Request | Yes |
| 35 | Modify Bearer Response | Yes |
| 36 | Delete Session Request | Yes |
| 37 | Delete Session Response | Yes |
| 38 | Change Notification Request | |
| 39 | Change Notification Response | |
| 40 | Remote UE Report Notification | |
| 41 | Remote UE Report Acknowledge | |
| 42-63 | (Spare/Reserved) | - |
| 64 | Modify Bearer Command | Yes |
| 65 | Modify Bearer Failure Indication | Yes |
| 66 | Delete Bearer Command | Yes |
| 67 | Delete Bearer Failure Indication | Yes |
| 68 | Bearer Resource Command | |
| 69 | Bearer Resource Failure Indication | |
| 70 | Downlink Data Notification Failure Indication | Yes |
| 71 | Trace Session Activation | |
| 72 | Trace Session Deactivation | |
| 73 | Stop Paging Indication | Yes |
| 74-94 | (Spare/Reserved) | - |
| 95 | Create Bearer Request | Yes |
| 96 | Create Bearer Response | Yes |
| 97 | Update Bearer Request | Yes |
| 98 | Update Bearer Response | Yes |
| 99 | Delete Bearer Request | Yes |
| 100 | Delete Bearer Response | Yes |
| 101 | Delete PDN Connection Set Request | Yes |
| 102 | Delete PDN Connection Set Response | Yes |
| 103 | PGW Downlink Triggering Notification | |
| 104 | PGW Downlink Triggering Acknowledge | |
| 105-127 | (Spare/Reserved) | - |
| 128 | Identification Request | |
| 129 | Identification Response | |
| 130 | Context Request | Yes |
| 131 | Context Response | Yes |
| 132 | Context Acknowledge | Yes |
| 133 | Forward Relocation Request | |
| 134 | Forward Relocation Response | |
| 135 | Forward Relocation Complete Notification | |
| 136 | Forward Relocation Complete Acknowledge | |
| 137 | Forward Access Context Notification | |
| 138 | Forward Access Context Acknowledge | |
| 139 | Relocation Cancel Request | |
| 140 | Relocation Cancel Response | |
| 141 | Configuration Transfer Tunnel | |
| 142-148 | (Spare/Reserved) | - |
| 149 | Detach Notification | Yes |
| 150 | Detach Acknowledge | Yes |
| 151 | CS Paging Indication | |
| 152 | RAN Information Relay | |
| 153 | Alert MME Notification | |
| 154 | Alert MME Acknowledge | |
| 155 | UE Activity Notification | |
| 156 | UE Activity Acknowledge | |
| 157 | ISR Status Indication | |
| 158 | UE Registration Query Request | |
| 159 | UE Registration Query Response | |
| 160 | Create Forwarding Tunnel Request | |
| 161 | Create Forwarding Tunnel Response | |
| 162 | Suspend Notification | Yes |
| 163 | Suspend Acknowledge | Yes |
| 164 | Resume Notification | Yes |
| 165 | Resume Acknowledge | Yes |
| 166 | Create Indirect Data Forwarding Tunnel Request | |
| 167 | Create Indirect Data Forwarding Tunnel Response | |
| 168 | Delete Indirect Data Forwarding Tunnel Request | |
| 169 | Delete Indirect Data Forwarding Tunnel Response | |
| 170 | Release Access Bearers Request | Yes |
| 171 | Release Access Bearers Response | Yes |
| 172-175 | (Spare/Reserved) | - |
| 176 | Downlink Data Notification | Yes |
| 177 | Downlink Data Notification Acknowledge | Yes |
| 178 | (Spare/Reserved) | - |
| 179 | PGW Restart Notification | Yes |
| 180 | PGW Restart Notification Acknowledge | Yes |
| 181-199 | (Spare/Reserved) | - |
| 200 | Update PDN Connection Set Request | Yes |
| 201 | Update PDN Connection Set Response | Yes |
| 202-210 | (Spare/Reserved) | - |
| 211 | Modify Access Bearers Request | Yes |
| 212 | Modify Access Bearers Response | Yes |
| 213-230 | (Spare/Reserved) | - |
| 231 | MBMS Session Start Request | |
| 232 | MBMS Session Start Response | |
| 233 | MBMS Session Update Request | |
| 234 | MBMS Session Update Response | |
| 235 | MBMS Session Stop Request | |
| 236 | MBMS Session Stop Response | |
| 237-239 | (Spare/Reserved) | - |
| 240-247 | (Spare/Reserved) | - |
| 248-255 | (Spare/Reserved) | - |
The following Information Elements marked with "Yes" are currently available with their own useful constructors.
Even there are some missing IEs, you can create any kind of IEs by using ie.New() function or by initializing ie.IE directly.
| ID | Name | Supported |
|---|---|---|
| 0 | (Spare/Reserved) | - |
| 1 | International Mobile Subscriber Identity (IMSI) | Yes |
| 2 | Cause | Yes |
| 3 | Recovery (Restart Counter) | Yes |
| 4-34 | (Spare/Reserved) | - |
| 35-50 | (Spare/Reserved) | - |
| 51 | STN-SR | |
| 52-70 | (Spare/Reserved) | - |
| 71 | Access Point Name (APN) | Yes |
| 72 | Aggregate Maximum Bit Rate (AMBR) | Yes |
| 73 | EPS Bearer ID (EBI) | Yes |
| 74 | IP Address | Yes |
| 75 | Mobile Equipment Identity (MEI) | Yes |
| 76 | MSISDN | Yes |
| 77 | Indication | Yes |
| 78 | Protocol Configuration Options (PCO) | Yes |
| 79 | PDN Address Allocation (PAA) | Yes |
| 80 | Bearer Level Quality of Service (Bearer QoS) | Yes |
| 81 | Flow Quality of Service (Flow QoS) | Yes |
| 82 | RAT Type | Yes |
| 83 | Serving Network | Yes |
| 84 | EPS Bearer Level Traffic Flow Template (Bearer TFT) | Yes |
| 85 | Traffic Aggregation Description (TAD) | |
| 86 | User Location Information (ULI) | Yes |
| 87 | Fully Qualified Tunnel Endpoint Identifier (F-TEID) | Yes |
| 88 | TMSI | Yes |
| 89 | Global CN-Id | Yes |
| 90 | S103 PDN Data Forwarding Info (S103PDF) | Yes |
| 91 | S1-U Data Forwarding Info (S1UDF) | Yes |
| 92 | Delay Value | Yes |
| 93 | Bearer Context | Yes |
| 94 | Charging ID | Yes |
| 95 | Charging Characteristics | Yes |
| 96 | Trace Information | |
| 97 | Bearer Flags | Yes |
| 98 | (Spare/Reserved) | - |
| 99 | PDN Type | Yes |
| 100 | Procedure Transaction ID | Yes |
| 101 | (Spare/Reserved) | - |
| 102 | (Spare/Reserved) | - |
| 103 | MM Context (GSM Key and Triplets) | |
| 104 | MM Context (UMTS Key, Used Cipher and Quintuplets) | |
| 105 | MM Context (GSM Key, Used Cipher and Quintuplets) | |
| 106 | MM Context (UMTS Key and Quintuplets) | |
| 107 | MM Context (EPS Security Context, Quadruplets and Quintuplets) | |
| 108 | MM Context (UMTS Key, Quadruplets and Quintuplets) | |
| 109 | PDN Connection | |
| 110 | PDU Numbers | |
| 111 | Packet TMSI | Yes |
| 112 | P-TMSI Signature | Yes |
| 113 | Hop Counter | Yes |
| 114 | UE Time Zone | Yes |
| 115 | Trace Reference | Yes |
| 116 | Complete Request Message | |
| 117 | GUTI | Yes |
| 118 | F-Container | |
| 119 | F-Cause | |
| 120 | PLMN ID | Yes |
| 121 | Target Identification | |
| 122 | (Spare/Reserved) | - |
| 123 | Packet Flow ID | |
| 124 | RAB Context | |
| 125 | Source RNC PDCP Context Info | |
| 126 | Port Number | Yes |
| 127 | APN Restriction | Yes |
| 128 | Selection Mode | Yes |
| 129 | Source Identification | |
| 130 | (Spare/Reserved) | - |
| 131 | Change Reporting Action | |
| 132 | Fully Qualified PDN Connection Set Identifier (FQ-CSID) | Yes |
| 133 | Channel Needed | |
| 134 | eMLPP Priority | |
| 135 | Node Type | Yes |
| 136 | Fully Qualified Domain Name (FQDN) | Yes |
| 137 | Transaction Identifier (TI) | |
| 138 | MBMS Session Duration | |
| 139 | MBMS Service Area | |
| 140 | MBMS Session Identifier | |
| 141 | MBMS Flow Identifier | |
| 142 | MBMS IP Multicast Distribution | |
| 143 | MBMS Distribution Acknowledge | |
| 144 | RFSP Index | |
| 145 | User CSG Information (UCI) | Yes |
| 146 | CSG Information Reporting Action | |
| 147 | CSG ID | Yes |
| 148 | CSG Membership Indication (CMI) | Yes |
| 149 | Service Indicator | Yes |
| 150 | Detach Type | Yes |
| 151 | Local Distinguished Name (LDN) | Yes |
| 152 | Node Features | Yes |
| 153 | MBMS Time to Data Transfer | |
| 154 | Throttling | Yes |
| 155 | Allocation/Retention Priority (ARP) | Yes |
| 156 | EPC Timer | Yes |
| 157 | Signalling Priority Indication | |
| 158 | Temporary Mobile Group Identity (TMGI) | |
| 159 | Additional MM context for SRVCC | |
| 160 | Additional flags for SRVCC | |
| 161 | (Spare/Reserved) | - |
| 162 | MDT Configuration | |
| 163 | Additional Protocol Configuration Options (APCO) | |
| 164 | Absolute Time of MBMS Data Transfer | |
| 165 | H(e)NB Information Reporting | |
| 166 | IPv4 Configuration Parameters (IP4CP) | |
| 167 | Change to Report Flags | |
| 168 | Action Indication | |
| 169 | TWAN Identifier | |
| 170 | ULI Timestamp | Yes |
| 171 | MBMS Flags | |
| 172 | RAN/NAS Cause | Yes |
| 173 | CN Operator Selection Entity | |
| 174 | Trusted WLAN Mode Indication | |
| 175 | Node Number | |
| 176 | Node Identifier | |
| 177 | Presence Reporting Area Action | |
| 178 | Presence Reporting Area Information | |
| 179 | TWAN Identifier Timestamp | |
| 180 | Overload Control Information | |
| 181 | Load Control Information | |
| 182 | Metric | |
| 183 | Sequence Number | |
| 184 | APN and Relative Capacity | |
| 185 | WLAN Offloadability Indication | |
| 186 | Paging and Service Information | Yes |
| 187 | Integer Number | Yes |
| 188 | Millisecond Time Stamp | |
| 189 | Monitoring Event Information | |
| 190 | ECGI List | |
| 191 | Remote UE Context | |
| 192 | Remote User ID | |
| 193 | Remote UE IP information | |
| 194 | CIoT Optimizations Support Indication | |
| 195 | SCEF PDN Connection | |
| 196 | Header Compression Configuration | |
| 197 | Extended Protocol Configuration Options (ePCO) | |
| 198 | Serving PLMN Rate Control | |
| 199 | Counter | |
| 200 | Mapped UE Usage Type | |
| 201 | Secondary RAT Usage Data Report | |
| 202 | UP Function Selection Indication Flags | |
| 203 | Maximum Packet Loss Rate | |
| 204 | APN Rate Control Status | |
| 205 | Extended Trace Information | |
| 206 | Monitoring Event Extension Information | |
| 207 | Additional RRM Policy Index | |
| 208 | V2X Context | |
| 209 | PC5 QoS Parameters | |
| 210 | Services Authorized | |
| 211 | Bit Rate | |
| 212 | PC5 QoS Flow | |
| 213-253 | (Spare/Reserved) | - |
| 254 | (Spare/Reserved) | - |
| 255 | Private Extension | Yes |