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package sip
import (
"log"
"net"
"strconv"
"time"
)
func ReceiveMessages(sock *net.UDPConn, c chan<- *Msg, e chan<- error) {
buf := make([]byte, 2048)
laddr := sock.LocalAddr().(*net.UDPAddr)
lhost := laddr.IP.String()
lport := uint16(laddr.Port)
for {
amt, addr, err := sock.ReadFromUDP(buf)
if err != nil {
e <- err
break
}
ts := time.Now()
packet := string(buf[0:amt])
if *tracing {
trace("recv", packet, addr)
}
msg, err := ParseMsg(packet)
if err != nil {
log.Println("Dropping SIP message:", err)
continue
}
addReceived(msg, addr)
addTimestamp(msg, ts)
if msg.Route != nil && msg.Route.Uri.Host == lhost && or5060(msg.Route.Uri.Port) == lport {
msg.Route = msg.Route.Next
}
fixMessagesFromStrictRouters(lhost, lport, msg)
c <- msg
}
close(c)
close(e) // Must be unbuffered!
}
func addReceived(msg *Msg, addr *net.UDPAddr) {
if msg.Via.Host != addr.IP.String() || int(msg.Via.Port) != addr.Port {
msg.Via.Params["received"] = addr.String()
}
}
func addTimestamp(msg *Msg, ts time.Time) {
if *timestampTagging {
msg.Via.Params["µsi"] = strconv.FormatInt(ts.UnixNano()/int64(time.Microsecond), 10)
}
}
// RFC3261 16.4 Route Information Preprocessing
// RFC3261 16.12.1.2: Traversing a Strict-Routing Proxy
func fixMessagesFromStrictRouters(lhost string, lport uint16, msg *Msg) {
if msg.Request != nil &&
msg.Request.Params.Has("lr") &&
msg.Route != nil &&
msg.Request.Host == lhost &&
or5060(msg.Request.Port) == lport {
var oldReq, newReq *URI
if msg.Route.Next == nil {
oldReq, newReq = msg.Request, msg.Route.Uri
msg.Request = msg.Route.Uri
msg.Route = nil
} else {
seclast := msg.Route
for ; seclast.Next.Next != nil; seclast = seclast.Next {
}
oldReq, newReq = msg.Request, seclast.Next.Uri
msg.Request = seclast.Next.Uri
seclast.Next = nil
msg.Route.Last()
}
log.Printf("Fixing request URI after strict router traversal: %s -> %s", oldReq, newReq)
}
}