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474 lines
11 KiB
474 lines
11 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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// SIP Message Library
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package sip
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import (
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"bytes"
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"net"
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"strconv"
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)
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// Msg represents a SIP message. This can either be a request or a response.
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// These fields are never nil unless otherwise specified.
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type Msg struct {
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// Fields that aren't headers.
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VersionMajor uint8
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VersionMinor uint8
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Method string // Indicates type of request (if request)
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Request *URI // dest URI (nil if response)
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Status int // Indicates happiness of response (if response)
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Phrase string // Explains happiness of response (if response)
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Payload Payload // Stuff that comes after two line breaks
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// Special non-SIP fields.
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SourceAddr *net.UDPAddr // Set by transport layer as received address.
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// Important headers should be further up in the struct.
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From *Addr // Logical sender of message
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To *Addr // Logical destination of message
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Via *Via // Linked list of agents traversed (must have one)
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Route *Addr // Used for goose routing and loose routing
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RecordRoute *Addr // Used for loose routing
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Contact *Addr // Where we send response packets or nil
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CallID string // Identifies call from invite to bye
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CSeq int // Counter for network packet ordering
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CSeqMethod string // Helps with matching to orig message
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MaxForwards int // 0 has context specific meaning
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UserAgent string
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// All the other RFC 3261 headers in plus some extras.
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Accept string
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AcceptContact string
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AcceptEncoding string
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AcceptLanguage string
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AlertInfo string
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Allow string
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AllowEvents string
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AuthenticationInfo string
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Authorization string
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CallInfo string
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ContentDisposition string
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ContentEncoding string
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ContentLanguage string
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Date string
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ErrorInfo string
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Event string
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Expires int // Seconds registration should expire.
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InReplyTo string
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MIMEVersion string
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MinExpires int // Registrars need this when responding
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Organization string
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PAssertedIdentity *Addr // P-Asserted-Identity or nil (used for PSTN ANI)
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Priority string
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ProxyAuthenticate string
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ProxyAuthorization string
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ProxyRequire string
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ReferTo string
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ReferredBy string
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RemotePartyID *Addr // Evil twin of P-Asserted-Identity.
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ReplyTo string
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Require string
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RetryAfter string
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Server string
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Subject string
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Supported string
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Timestamp string
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Unsupported string
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WWWAuthenticate string
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Warning string
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// Extension headers.
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XHeader *XHeader
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}
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//go:generate ragel -Z -G2 -o msg_parse.go msg_parse.rl
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func (msg *Msg) IsResponse() bool {
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return msg.Status > 0
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}
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func (msg *Msg) String() string {
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var b bytes.Buffer
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msg.Append(&b)
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return b.String()
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}
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func (msg *Msg) Copy() *Msg {
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if msg == nil {
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return nil
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}
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res := new(Msg)
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*res = *msg
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res.Request = msg.Request.Copy()
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res.To = msg.To.Copy()
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res.From = msg.From.Copy()
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res.Via = msg.Via.Copy()
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res.PAssertedIdentity = msg.PAssertedIdentity.Copy()
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res.RemotePartyID = msg.RemotePartyID.Copy()
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res.Route = msg.Route.Copy()
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res.Contact = msg.Contact.Copy()
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res.RecordRoute = msg.RecordRoute.Copy()
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res.XHeader = msg.XHeader
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return res
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}
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// I turn a SIP message back into a packet.
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func (msg *Msg) Append(b *bytes.Buffer) {
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if msg == nil {
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return
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}
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if !msg.IsResponse() {
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if msg.Method == "" {
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b.WriteString("INVITE ")
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} else {
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b.WriteString(msg.Method)
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b.WriteString(" ")
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}
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if msg.Request == nil {
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// In case of bugs, keep calm and DDOS NASA.
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b.WriteString("sip:www.nasa.gov:80")
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} else {
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msg.Request.Append(b)
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}
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b.WriteString(" ")
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msg.appendVersion(b)
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b.WriteString("\r\n")
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} else {
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if msg.Phrase == "" {
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msg.Phrase = Phrase(msg.Status)
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}
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msg.appendVersion(b)
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b.WriteString(" ")
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b.WriteString(strconv.Itoa(msg.Status))
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b.WriteString(" ")
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b.WriteString(msg.Phrase)
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b.WriteString("\r\n")
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}
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b.WriteString("From: ")
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msg.From.Append(b)
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b.WriteString("\r\n")
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b.WriteString("To: ")
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msg.To.Append(b)
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b.WriteString("\r\n")
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for viap := msg.Via; viap != nil; viap = viap.Next {
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b.WriteString("Via: ")
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viap.Append(b)
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b.WriteString("\r\n")
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}
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if msg.Route != nil {
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b.WriteString("Route: ")
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msg.Route.Append(b)
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b.WriteString("\r\n")
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}
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if msg.RecordRoute != nil {
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b.WriteString("Record-Route: ")
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msg.RecordRoute.Append(b)
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b.WriteString("\r\n")
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}
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if msg.Contact != nil {
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b.WriteString("Contact: ")
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msg.Contact.Append(b)
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b.WriteString("\r\n")
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}
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b.WriteString("Call-ID: ")
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b.WriteString(msg.CallID)
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b.WriteString("\r\n")
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b.WriteString("CSeq: ")
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b.WriteString(strconv.Itoa(msg.CSeq))
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b.WriteString(" ")
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b.WriteString(msg.CSeqMethod)
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b.WriteString("\r\n")
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if msg.UserAgent != "" {
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b.WriteString("User-Agent: ")
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b.WriteString(msg.UserAgent)
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b.WriteString("\r\n")
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}
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if !msg.IsResponse() {
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if msg.MaxForwards == 0 {
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b.WriteString("Max-Forwards: 70\r\n")
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} else {
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b.WriteString("Max-Forwards: ")
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b.WriteString(strconv.Itoa(msg.MaxForwards))
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b.WriteString("\r\n")
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}
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}
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if msg.Accept != "" {
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b.WriteString("Accept: ")
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b.WriteString(msg.Accept)
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b.WriteString("\r\n")
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}
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if msg.AcceptEncoding != "" {
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b.WriteString("Accept-Encoding: ")
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b.WriteString(msg.AcceptEncoding)
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b.WriteString("\r\n")
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}
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if msg.AcceptLanguage != "" {
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b.WriteString("Accept-Language: ")
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b.WriteString(msg.AcceptLanguage)
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b.WriteString("\r\n")
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}
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if msg.AlertInfo != "" {
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b.WriteString("Alert-Info: ")
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b.WriteString(msg.AlertInfo)
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b.WriteString("\r\n")
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}
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if msg.Allow != "" {
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b.WriteString("Allow: ")
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b.WriteString(msg.Allow)
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b.WriteString("\r\n")
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}
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if msg.AllowEvents != "" {
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b.WriteString("Allow-Events: ")
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b.WriteString(msg.AllowEvents)
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b.WriteString("\r\n")
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}
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if msg.AuthenticationInfo != "" {
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b.WriteString("Authentication-Info: ")
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b.WriteString(msg.AuthenticationInfo)
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b.WriteString("\r\n")
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}
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if msg.Authorization != "" {
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b.WriteString("Authorization: ")
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b.WriteString(msg.Authorization)
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b.WriteString("\r\n")
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}
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if msg.CallInfo != "" {
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b.WriteString("Call-Info: ")
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b.WriteString(msg.CallInfo)
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b.WriteString("\r\n")
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}
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if msg.ContentDisposition != "" {
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b.WriteString("Content-Disposition: ")
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b.WriteString(msg.ContentDisposition)
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b.WriteString("\r\n")
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}
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if msg.ContentEncoding != "" {
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b.WriteString("Content-Encoding: ")
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b.WriteString(msg.ContentEncoding)
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b.WriteString("\r\n")
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}
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if msg.ContentLanguage != "" {
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b.WriteString("Content-Language: ")
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b.WriteString(msg.ContentLanguage)
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b.WriteString("\r\n")
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}
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if msg.Date != "" {
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b.WriteString("Date: ")
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b.WriteString(msg.Date)
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b.WriteString("\r\n")
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}
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if msg.ErrorInfo != "" {
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b.WriteString("Error-Info: ")
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b.WriteString(msg.ErrorInfo)
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b.WriteString("\r\n")
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}
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if msg.Event != "" {
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b.WriteString("Event: ")
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b.WriteString(msg.Event)
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b.WriteString("\r\n")
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}
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// Expires is allowed to be 0 for for REGISTER stuff.
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if msg.Expires > 0 || msg.Method == "REGISTER" || msg.CSeqMethod == "REGISTER" {
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b.WriteString("Expires: ")
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b.WriteString(strconv.Itoa(msg.Expires))
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b.WriteString("\r\n")
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}
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if msg.InReplyTo != "" {
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b.WriteString("In-Reply-To: ")
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b.WriteString(msg.InReplyTo)
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b.WriteString("\r\n")
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}
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if msg.MIMEVersion != "" {
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b.WriteString("MIME-Version: ")
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b.WriteString(msg.MIMEVersion)
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b.WriteString("\r\n")
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}
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if msg.MinExpires > 0 {
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b.WriteString("Min-Expires: ")
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b.WriteString(strconv.Itoa(msg.MinExpires))
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b.WriteString("\r\n")
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}
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if msg.Organization != "" {
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b.WriteString("Organization: ")
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b.WriteString(msg.Organization)
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b.WriteString("\r\n")
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}
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if msg.PAssertedIdentity != nil {
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b.WriteString("P-Asserted-Identity: ")
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msg.PAssertedIdentity.Append(b)
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b.WriteString("\r\n")
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}
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if msg.Priority != "" {
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b.WriteString("Priority: ")
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b.WriteString(msg.Priority)
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b.WriteString("\r\n")
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}
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if msg.ProxyAuthenticate != "" {
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b.WriteString("Proxy-Authenticate: ")
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b.WriteString(msg.ProxyAuthenticate)
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b.WriteString("\r\n")
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}
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if msg.ProxyAuthorization != "" {
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b.WriteString("Proxy-Authorization: ")
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b.WriteString(msg.ProxyAuthorization)
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b.WriteString("\r\n")
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}
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if msg.ProxyRequire != "" {
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b.WriteString("Proxy-Require: ")
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b.WriteString(msg.ProxyRequire)
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b.WriteString("\r\n")
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}
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if msg.ReferTo != "" {
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b.WriteString("Refer-To: ")
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b.WriteString(msg.ReferTo)
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b.WriteString("\r\n")
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}
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if msg.ReferredBy != "" {
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b.WriteString("Referred-By: ")
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b.WriteString(msg.ReferredBy)
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b.WriteString("\r\n")
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}
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if msg.RemotePartyID != nil {
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b.WriteString("Remote-Party-ID: ")
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msg.RemotePartyID.Append(b)
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b.WriteString("\r\n")
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}
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if msg.ReplyTo != "" {
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b.WriteString("Reply-To: ")
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b.WriteString(msg.ReplyTo)
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b.WriteString("\r\n")
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}
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if msg.Require != "" {
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b.WriteString("Require: ")
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b.WriteString(msg.Require)
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b.WriteString("\r\n")
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}
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if msg.RetryAfter != "" {
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b.WriteString("RetryAfter: ")
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b.WriteString(msg.RetryAfter)
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b.WriteString("\r\n")
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}
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if msg.Server != "" {
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b.WriteString("Server: ")
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b.WriteString(msg.Server)
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b.WriteString("\r\n")
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}
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if msg.Subject != "" {
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b.WriteString("Subject: ")
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b.WriteString(msg.Subject)
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b.WriteString("\r\n")
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}
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if msg.Supported != "" {
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b.WriteString("Supported: ")
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b.WriteString(msg.Supported)
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b.WriteString("\r\n")
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}
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if msg.Timestamp != "" {
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b.WriteString("Timestamp: ")
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b.WriteString(msg.Timestamp)
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b.WriteString("\r\n")
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}
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if msg.Unsupported != "" {
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b.WriteString("Unsupported: ")
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b.WriteString(msg.Unsupported)
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b.WriteString("\r\n")
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}
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if msg.Warning != "" {
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b.WriteString("Warning: ")
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b.WriteString(msg.Warning)
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b.WriteString("\r\n")
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}
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if msg.WWWAuthenticate != "" {
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b.WriteString("WWW-Authenticate: ")
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b.WriteString(msg.WWWAuthenticate)
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b.WriteString("\r\n")
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}
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msg.XHeader.Append(b)
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if msg.Payload != nil {
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b.WriteString("Content-Type: ")
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b.WriteString(msg.Payload.ContentType())
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b.WriteString("\r\n")
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payload := msg.Payload.Data()
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b.WriteString("Content-Length: ")
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b.WriteString(strconv.Itoa(len(payload)))
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b.WriteString("\r\n\r\n")
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b.Write(payload)
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} else {
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b.WriteString("Content-Length: 0\r\n\r\n")
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}
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}
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func (msg *Msg) appendVersion(b *bytes.Buffer) {
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b.WriteString("SIP/")
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if msg.VersionMajor == 0 {
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b.WriteString("2.0")
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} else {
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b.WriteString(strconv.FormatUint(uint64(msg.VersionMajor), 10))
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b.WriteString(".")
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b.WriteString(strconv.FormatUint(uint64(msg.VersionMinor), 10))
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}
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}
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