/
dialog.go
161 lines (129 loc) · 3.7 KB
/
dialog.go
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package sip
import (
"errors"
"fmt"
"net/http"
"strconv"
"time"
)
const (
StatusOK = 200
StatusRequestCancelled = 487
StatusDecline = 603
)
type Dialog struct {
transport Transport
caller URI
authenticationHandlers []AuthenticationHandler
cseq int
callID string
}
func NewDialog(transport Transport, caller URI, authenticationHandlers ...AuthenticationHandler) *Dialog {
return &Dialog{
transport: transport,
caller: caller,
authenticationHandlers: authenticationHandlers,
cseq: 1,
callID: fmt.Sprintf("c%d", time.Now().Unix()),
}
}
func (d *Dialog) Ring(callee URI, maxRingingTime time.Duration) (bool, error) {
inviteRequest := d.invite(callee, maxRingingTime)
con, err := d.transport.Send(inviteRequest)
if err != nil {
return false, err
}
defer con.Close()
inviteResponse, err := RecvFinal(con)
if err != nil {
return false, err
}
var authenticationChallenge AuthenticationChallenge
if inviteResponse.StatusCode == http.StatusUnauthorized {
authenticationChallenge, err = parseWWWAuthenticateHeader(inviteResponse.Header.Get("WWW-Authenticate"))
if err != nil {
return false, err
}
if err := d.authenticate(inviteRequest, authenticationChallenge); err != nil {
return false, err
}
if err := con.Send(inviteRequest); err != nil {
return false, err
}
inviteResponse, err = RecvFinal(con)
if err != nil {
return false, err
}
}
accepted := inviteResponse.StatusCode == StatusOK
to := inviteResponse.Header.Get("To")
ack, err := d.ack(callee, to, authenticationChallenge)
if err != nil {
return false, err
}
if err := con.Send(ack); err != nil {
return false, err
}
d.cseq++
bye := d.request("BYE", callee)
bye.Header.Set("To", to)
if err := con.Send(bye); err != nil {
return false, err
}
resp, err := RecvFinal(con)
if err != nil {
return false, err
}
if resp.StatusCode != StatusOK {
return false, fmt.Errorf("Got unexpected status from BYE: %d", resp.StatusCode)
}
return accepted, nil
}
func (d *Dialog) invite(callee URI, maxRingingTime time.Duration) *Request {
r := d.request("INVITE", callee)
r.Header.Add("Expires", strconv.Itoa(int(maxRingingTime.Seconds())))
return r
}
func (d *Dialog) ack(callee URI, to string, authenticationChallenge AuthenticationChallenge) (*Request, error) {
r := d.request("ACK", callee)
r.Header.Set("To", to)
r.SetBody("application/sdp", []byte(d.formatSDP()))
if authenticationChallenge.Method != "" {
err := d.authenticate(r, authenticationChallenge)
if err != nil {
return nil, err
}
}
return r, nil
}
func (d *Dialog) formatSDP() string {
sessionId := time.Now().UnixMilli()
version := sessionId
addr := "fe80::b644:fe20:c499:dd4e"
return fmt.Sprintf("v=0\r\no=klingel1 %d %d IN IP6 %s\r\ns=\r\nc=IN IP6 %s\r\nt=0 0\r\n", sessionId, version, addr, addr)
}
func (d *Dialog) request(method string, callee URI) *Request {
req := NewRequest(method, callee)
req.Header.Set("From", d.caller.String())
req.Header.Set("To", callee.String())
req.Header.Set("Contact", d.caller.String())
req.Header.Set("Max-Forwards", "70")
req.Header.Set("Cseq", fmt.Sprintf("%d %s", d.cseq, req.Method))
req.Header.Set("Call-ID", d.callID)
return req
}
func (d *Dialog) authenticate(req *Request, c AuthenticationChallenge) error {
for _, h := range d.authenticationHandlers {
err := h.Solve(c, req)
if err == nil {
d.cseq++
req.Header.Set("Cseq", fmt.Sprintf("%d %s", d.cseq, req.Method))
return nil
}
if errors.Is(err, ErrUnsolveableAuthenticationChallenge) {
continue
}
return err
}
return ErrUnsolveableAuthenticationChallenge
}