Improve STUN/DTLS/SRTP demux, use example from RFC

This commit is contained in:
Sean DuBois
2018-07-14 13:23:53 -07:00
parent ec5c743b55
commit 0c8abd0bc3
2 changed files with 21 additions and 22 deletions

View File

@@ -21,7 +21,11 @@ type incomingPacket struct {
buffer []byte
}
func (p *Port) handleSRTP(b BufferTransportGenerator, certPair *dtls.CertPair, buffer []byte) {
func (p *Port) handleSRTP(b BufferTransportGenerator, buffer []byte) {
if p.certPair == nil {
fmt.Printf("Got SRTP packet but no DTLS state to handle it %v \n", p.certPair)
return
}
if len(buffer) > 4 {
var rtcpPacketType uint8
@@ -48,7 +52,7 @@ func (p *Port) handleSRTP(b BufferTransportGenerator, certPair *dtls.CertPair, b
srtpContext, ok := p.srtpContexts[contextMapKey]
if !ok {
var err error
srtpContext, err = srtp.CreateContext([]byte(certPair.ServerWriteKey[0:16]), []byte(certPair.ServerWriteKey[16:]), certPair.Profile, packet.SSRC)
srtpContext, err = srtp.CreateContext([]byte(p.certPair.ServerWriteKey[0:16]), []byte(p.certPair.ServerWriteKey[16:]), p.certPair.Profile, packet.SSRC)
if err != nil {
fmt.Println("Failed to build SRTP context")
return
@@ -115,33 +119,26 @@ func (p *Port) handleSCTP(raw []byte, a *sctp.Association) {
}
}
func (p *Port) handleDTLS(raw []byte, srcAddr *net.UDPAddr, certPair *dtls.CertPair) bool {
if len(raw) < 0 || (raw[0] < 19 || raw[0] > 65) {
return false
}
func (p *Port) handleDTLS(raw []byte, srcAddr *net.UDPAddr) {
dtlsState := p.dtlsStates[srcAddr.String()]
association := p.sctpAssocations[srcAddr.String()]
if dtlsState == nil || association == nil {
fmt.Printf("Got DTLS packet but no DTLS/SCTP state to handle it %v %v \n", dtlsState, association)
return true
}
if decrypted := dtlsState.HandleDTLSPacket(raw); len(decrypted) > 0 {
p.handleSCTP(decrypted, association)
}
if certPair == nil {
certPair = dtlsState.GetCertPair()
if certPair != nil {
if certPair := dtlsState.GetCertPair(); certPair != nil && p.certPair == nil {
p.certPair = certPair
if p.certPair != nil {
p.authedConnections = append(p.authedConnections, &authedConnection{
pair: certPair,
pair: p.certPair,
peer: srcAddr,
})
}
}
return true
}
const iceTimeout = time.Second * 10
@@ -168,7 +165,6 @@ func (p *Port) networkLoop(remoteKey []byte, tlscfg *dtls.TLSCfg, b BufferTransp
}
}()
var certPair *dtls.CertPair
// Never timeout originally, only start timer after we get an ICE ping
iceTimer := time.NewTimer(time.Hour * 8760)
for {
@@ -189,16 +185,18 @@ func (p *Port) networkLoop(remoteKey []byte, tlscfg *dtls.TLSCfg, b BufferTransp
return
}
if p.handleDTLS(in.buffer, in.srcAddr, certPair) {
if len(in.buffer) == 0 {
fmt.Println("Inbound buffer is not long enough to demux")
continue
}
if packetType, err := stun.GetPacketType(in.buffer); err == nil && packetType == stun.PacketTypeSTUN {
// https://tools.ietf.org/html/rfc5764#page-14
if 127 < in.buffer[0] && in.buffer[0] < 192 {
p.handleSRTP(b, in.buffer)
} else if 19 < in.buffer[0] && in.buffer[0] < 64 {
p.handleDTLS(in.buffer, in.srcAddr)
} else if in.buffer[0] < 2 {
p.handleICE(in, remoteKey, iceTimer, iceNotifier)
} else if certPair == nil {
fmt.Println("SRTP packet, but unable to handle DTLS handshake has not completed")
} else {
p.handleSRTP(b, certPair, in.buffer)
}
if _, ok := p.dtlsStates[in.srcAddr.String()]; !ok {

View File

@@ -41,7 +41,8 @@ type Port struct {
association *sctp.Association
conn *ipv4.PacketConn
conn *ipv4.PacketConn
certPair *dtls.CertPair
}
// NewPort creates a new Port