GitHub - emiago/sipgo: SIP library for writing fast SIP services in GO

SIPGO is library for writing fast SIP services in GO language.
It comes with SIP stack (RFC 3261|RFC3581|RFC6026) optimized for fast parsing.

Libs on top of sipgo:

diago github.com/emiago/diago: Full VOIP library/framework with media stack (Active development)

Fetch lib with:

go get github.com/emiago/sipgo

If you like/use project currently and looking for support/sponsoring checkout Support section

You can follow on X/Twitter for more updates.

More on documentation you can find on Go doc

Supported protocols

RFC:

State of Torture Tests RFC4475 you can find on issue github.com/emiago/sipgo/issues/57 but NOTE: some strict validation things may be seperated from parsing or not built into library.

Examples

Stateful proxy example/proxysip
Register with authentication example/register
Call and media with diago examples diago/examples

Also thanks to pion project sharing this example of using SIPgo with webrtc:

https://github.com/pion/example-webrtc-applications/tree/master/sip-to-webrtc original post on X

Performance

SIPgo was proven that can excel in performance compared to some other configured base proxy solutions.

As an example, you can find example/proxysip as simple version of statefull proxy. It is used for stress testing with sipp. To find out more about performance check the latest results:
example/proxysip

Usage

Lib allows you to write easily sip servers, clients, stateful proxies, registrars or any sip routing. Writing in GO we are not limited to handle SIP requests/responses in many ways, or to integrate and scale with any external services (databases, caches...).

UAS/UAC build

Using server or client handle for UA you can build incoming or outgoing requests.

ua, _ := sipgo.NewUA() // Build user agent
srv, _ := sipgo.NewServer(ua) // Creating server handle for ua
client, _ := sipgo.NewClient(ua) // Creating client handle for ua
srv.OnInvite(inviteHandler)
srv.OnAck(ackHandler)
srv.OnBye(byeHandler)

// For registrars
// srv.OnRegister(registerHandler)
ctx, _ := signal.NotifyContext(ctx, os.Interrupt)
go srv.ListenAndServe(ctx, "udp", "127.0.0.1:5060")
go srv.ListenAndServe(ctx, "tcp", "127.0.0.1:5061")
go srv.ListenAndServe(ctx, "ws", "127.0.0.1:5080")
<-ctx.Done()

Server handle creates listeners and reacts on incoming requests. More on server transactions
Client handle allows creating transaction requests More on client transactions

TLS transports

// TLS
conf := generateTLSConfig(certFile, keyFile, rootPems)
srv.ListenAndServeTLS(ctx, "tcp", "127.0.0.1:5061", conf)
srv.ListenAndServeTLS(ctx, "ws", "127.0.0.1:5081", conf)

func generateTLSConfig(certFile string, keyFile string, rootPems []byte) (*tls.Config, error) {
	roots := x509.NewCertPool()
	if rootPems != nil {
		ok := roots.AppendCertsFromPEM(rootPems)
		if !ok {
			return nil, fmt.Errorf("failed to parse root certificate")
		}
	}

	cert, err := tls.LoadX509KeyPair(certFile, keyFile)
	if err != nil {
		return nil, fmt.Errorf("fail to load cert. err=%w", err)
	}

	conf := &tls.Config{
		Certificates: []tls.Certificate{cert},
		RootCAs:      roots,
	}

	return conf, nil
}

UAC first

If you are acting as client first, you can say to client which host:port to use, and this connection will be reused until closing UA. Any request received can be still processed with server handle.

ua, _ := sipgo.NewUA() // Build user agent
defer ua.Close()

client, _ := sipgo.NewClient(ua, sipgo.WithClientHostname("127.0.0.1"), sipgo.WithClientPort(5060))
server, _ := sipgo.NewServer(ua) 
srv.OnBye(func(req *sip.Request, tx sip.ServerTransaction)) {
    // This will be received on 127.0.0.1:5060
}

tx, err := client.TransactionRequest(ctx, sip.NewRequest(sip.INVITE, recipient))

Server Transaction

Server transaction is passed on handler

// Incoming request
srv.OnInvite(func(req *sip.Request, tx sip.ServerTransaction) {
    // Send provisional
    res := sip.NewResponseFromRequest(req, 100, "Trying", nil)
    tx.Respond(res)
    
    // Send OK. TODO: some body like SDP
    res := sip.NewResponseFromRequest(req, 200, "OK", body)
    tx.Respond(res)

    // Wait transaction termination.
    select {
        case m := <-tx.Acks(): // Handle ACK for response . ACKs on 2xx are send as different request
        case <-tx.Done():
            // Signal transaction is done. 
            // Check any errors with tx.Err() to have more info why terminated
            return
    }
    // terminating handler terminates Server transaction automaticaly
})

Server stateless response

srv := sipgo.NewServer()
...
func ackHandler(req *sip.Request, tx sip.ServerTransaction) {
    res := sip.NewResponseFromRequest(req, code, reason, body)
    srv.WriteResponse(res)
}
srv.OnACK(ackHandler)

Client Do request

Unless you need more control over Client Transaction you can simply go with client Do request and wait final response (following std http package).

req := sip.NewRequest(sip.INVITE, sip.Uri{User:"bob", Host: "example.com"})
res, err := client.Do(req)

Client Transaction

Using client handle allows easy creating and sending request. Unless you customize transaction request with opts by default client.TransactionRequest will build all other headers needed to pass correct sip request.

Here is full example:

ctx := context.Background()
client, _ := sipgo.NewClient(ua) // Creating client handle

req := sip.NewRequest(sip.INVITE, sip.Uri{User:"bob", Host: "example.com"})
tx, err := client.TransactionRequest(ctx, req) // Send request and get client transaction handle

defer tx.Terminate() // Client Transaction must be terminated for cleanup
...

select {
    case res := <-tx.Responses():
    // Handle responses
    case <-tx.Done():
    // Wait for termination
    return
}

CSEQ Header increase rule:

Every new transaction will have implicitely CSEQ increase if present -> Issue 160. This fixes problem when you are passing same request like ex. REGISTER
Above rule does not apply for In Dialog cases
To avoid 1. pass option client.TransactionRequest(ctx, req, sipgo.ClientRequestBuild) or more better used DialogClient

Client stateless request

client, _ := sipgo.NewClient(ua) // Creating client handle
req := sip.NewRequest(sip.ACK, sip.Uri{User:"bob", Host: "example.com"})
// Send request and forget
client.WriteRequest(req)

Dialog handling

DialogUA is helper struct to create Dialog. Dialog can be as server or as client created. Later on this provides you RFC way of sending request within dialog Do or TransactionRequest functions.

For basic usage DialogClientCache and DialogServerCache are created to be part of library to manage and cache dialog accross multiple request. They are seperated based on your request context, but they act more like peer.

NOTE: It is recomended that you build your OWN Dialog Server/Client Cache mechanism for dialogs.

For basic control some handling request wrappers like Ack, Bye, ReadAck, ReadBye is provided. Sending any other request should be done with Do or receiving can be validated with ReadRequest

UAC:

ua, _ := sipgo.NewUA() // Build user agent
srv, _ := sipgo.NewServer(ua) // Creating server handle
client, _ := sipgo.NewClient(ua) // Creating client handle

contactHDR := sip.ContactHeader{
    Address: sip.Uri{User: "test", Host: "127.0.0.200", Port: 5088},
}
dialogCli := sipgo.NewDialogClientCache(client, contactHDR)

// Attach Bye handling for dialog
srv.OnBye(func(req *sip.Request, tx sip.ServerTransaction) {
    err := dialogCli.ReadBye(req, tx)
    //handle error
})

// Create dialog session
dialog, err := dialogCli.Invite(ctx, recipientURI, nil)
defer dialog.Close() // Cleans up from dialog pool
// Wait for answer
err = dialog.WaitAnswer(ctx, AnswerOptions{})
// Check dialog response dialog.InviteResponse (SDP) and return ACK
err = dialog.Ack(ctx)
// Send BYE to terminate call
err = dialog.Bye(ctx)

UAS:

ua, _ := sipgo.NewUA() // Build user agent
srv, _ := sipgo.NewServer(ua) // Creating server handle
client, _ := sipgo.NewClient(ua) // Creating client handle

uasContact := sip.ContactHeader{
    Address: sip.Uri{User: "test", Host: "127.0.0.200", Port: 5099},
}
dialogSrv := sipgo.NewDialogServerCache(client, uasContact)

srv.OnInvite(func(req *sip.Request, tx sip.ServerTransaction) {
    dlg, err := dialogSrv.ReadInvite(req, tx)
    if err != nil {
        return err
    }
    defer dlg.Close() // Close for cleanup from cache
    // handle error
    dlg.Respond(sip.StatusTrying, "Trying", nil)
    dlg.Respond(sip.StatusOK, "OK", nil)
    
    // Instead Done also dlg.State() can be used for granular state checking
    <-dlg.Context().Done()
})

srv.OnAck(func(req *sip.Request, tx sip.ServerTransaction) {
    dialogSrv.ReadAck(req, tx)
})

srv.OnBye(func(req *sip.Request, tx sip.ServerTransaction) {
    dialogSrv.ReadBye(req, tx)
})

Dialog Do/Transaction request

For any other request within dialog you should use dialog.Do to send request. Requests withing dialog need more checks to pass and therefore this API helps to keep requests within dialog session.

req := sip.NewRequest(sip.INFO, recipient)
res, err := dialog.Do(ctx, req)

Stateful Proxy build

Proxy is combination client and server handle that creates server/client transaction. They need to share same ua same like uac/uas build.

Forwarding request is done via client handle:

ua, _ := sipgo.NewUA() // Build user agent
srv, _ := sipgo.NewServer(ua) // Creating server handle
client, _ := sipgo.NewClient(ua) // Creating client handle

srv.OnInvite(func(req *sip.Request, tx sip.ServerTransaction) {
    ctx := context.Background()
    req.SetDestination("10.1.2.3") // Change sip.Request destination
    // Start client transaction and relay our request. Add Via and Record-Route header
    clTx, err := client.TransactionRequest(ctx, req, sipgo.ClientRequestAddVia, sipgo.ClientRequestAddRecordRoute)
    // Send back response
    res := <-cltx.Responses()
    tx.Respond(res)
})

SIP Debug

You can have full SIP messages dumped from transport into Debug level message.

Example:

Feb 24 23:32:26.493191 DBG UDP read 10.10.0.10:5060 <- 10.10.0.100:5060:
SIP/2.0 100 Trying
Via: SIP/2.0/UDP 10.10.0.10:5060;rport=5060;received=10.10.0.10;branch=z9hG4bK.G3nCwpXAKJQ0T2oZUII70wuQx9NeXc61;alias
Via: SIP/2.0/UDP 10.10.1.1:5060;branch=z9hG4bK-1-1-0
Record-Route: <sip:10.10.0.10;transport=udp;lr>
Call-ID: 1-1@10.10.1.1
From: "sipp" <sip:sipp@10.10.1.1>;tag=1SIPpTag001
To: "uac" <sip:uac@10.10.0.10>
CSeq: 1 INVITE
Server: Asterisk PBX 18.16.0
Content-Length:  0

Support

If you find this project interesting for bigger support or consulting, you can contact me on mail

For bugs features pls create issue.

Extra

E2E/integration testing

If you are interested using lib for your testing services then checkout article on how easy you can make calls and other

Tests

Library will be covered with more tests. Focus is more on benchmarking currently.

Credits

This project was influenced by gosip, project by @ghetovoice, but started as new project to achieve best/better performance and to improve API. This unfortunately required many design changes, therefore this libraries are not compatible.