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149 lines
3.9 KiB
149 lines
3.9 KiB
// Copyright 2020 Justine Alexandra Roberts Tunney
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package sip
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import (
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"errors"
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"log"
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"net"
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"strconv"
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"github.com/jart/gosip/util"
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)
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type AddressRoute struct {
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Address string
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Next *AddressRoute
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}
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func PopulateMessage(via *Via, contact *Addr, msg *Msg) {
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if !msg.IsResponse() {
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if msg.Via == nil {
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msg.Via = via
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}
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if msg.Contact == nil {
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msg.Contact = contact
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}
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if msg.To == nil {
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msg.To = &Addr{Uri: msg.Request}
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}
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if msg.From == nil {
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msg.From = msg.Contact.Copy()
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msg.From.Uri.Param = nil
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}
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if msg.CallID == "" {
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msg.CallID = util.GenerateCallID()
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}
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if msg.CSeq == 0 {
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msg.CSeq = util.GenerateCSeq()
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}
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if msg.CSeqMethod == "" {
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msg.CSeqMethod = msg.Method
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}
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if msg.MaxForwards == 0 {
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msg.MaxForwards = 70
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}
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if msg.UserAgent == "" {
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msg.UserAgent = GosipUA
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}
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if msg.Via.Param.Get("branch") == nil {
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msg.Via.Param = &Param{"branch", util.GenerateBranch(), msg.Via.Param}
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}
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if msg.From.Param.Get("tag") == nil {
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msg.From.Param = &Param{"tag", util.GenerateTag(), msg.From.Param}
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}
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}
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}
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func RouteMessage(via *Via, contact *Addr, msg *Msg) (host string, port uint16, err error) {
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if msg.IsResponse() {
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if via.CompareHostPort(msg.Via) {
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msg.Via = msg.Via.Next
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}
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host, port = msg.Via.Host, msg.Via.Port
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if received := msg.Via.Param.Get("received"); received != nil {
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host = received.Value
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}
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// fix: Get real port from rport field.
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// Request path like UAC->NAT->UAS will change port(according to NAT type) sometime,
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// we should use rport as real port in request-line
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if rport := msg.Via.Param.Get("rport"); rport != nil && len(rport.Value) > 0 {
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i, err := strconv.ParseInt(rport.Value, 10, 16)
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if err != nil {
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return "", 0, err
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}
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port = uint16(i)
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}
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} else {
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if contact.CompareHostPort(msg.Route) {
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msg.Route = msg.Route.Next
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}
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if msg.Route != nil {
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if msg.Method == "REGISTER" {
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return "", 0, errors.New("Don't route REGISTER requests")
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}
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if msg.Route.Uri.Param.Get("lr") != nil {
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// RFC3261 16.12.1.1 Basic SIP Trapezoid
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host, port = msg.Route.Uri.Host, msg.Route.Uri.Port
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} else {
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// RFC3261 16.12.1.2: Traversing a Strict-Routing Proxy
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msg.Route = msg.Route.Copy()
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msg.Route.Last().Next = &Addr{Uri: msg.Request}
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msg.Request = msg.Route.Uri
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msg.Route = msg.Route.Next
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host, port = msg.Request.Host, msg.Request.Port
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}
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} else {
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host, port = msg.Request.Host, msg.Request.Port
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}
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}
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return
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}
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func RouteAddress(host string, port uint16, wantSRV bool) (routes *AddressRoute, err error) {
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if net.ParseIP(host) != nil {
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if port == 0 {
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port = 5060
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}
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return &AddressRoute{Address: net.JoinHostPort(host, portstr(port))}, nil
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}
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if port == 0 {
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if wantSRV {
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_, srvs, err := net.LookupSRV("sip", "udp", host)
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if err == nil && len(srvs) > 0 {
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s := ""
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for i := len(srvs) - 1; i >= 0; i-- {
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routes = &AddressRoute{
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Address: net.JoinHostPort(srvs[i].Target, portstr(srvs[i].Port)),
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Next: routes,
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}
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s = " " + routes.Address + s
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}
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log.Printf("%s routes to: %s\r\n", host, s)
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return routes, nil
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}
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log.Printf("net.LookupSRV(sip, udp, %s) failed: %s\r\n", host, err)
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}
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port = 5060
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}
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addr, err := net.ResolveUDPAddr("udp", net.JoinHostPort(host, portstr(port)))
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if err != nil {
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return nil, err
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}
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return &AddressRoute{Address: addr.String()}, nil
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}
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