// SIP Via Address Library
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package sip
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import (
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"bytes"
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"errors"
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"github.com/jart/gosip/util"
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"strconv"
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)
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var (
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ViaBadHeader = errors.New("Bad Via header")
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ViaProtoBlank = errors.New("Via Transport blank")
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)
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// Example: SIP/2.0/UDP 1.2.3.4:5060;branch=z9hG4bK556f77e6.
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type Via struct {
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Protocol string // should be "SIP"
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Version string // protocol version e.g. "2.0"
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Transport string // transport type "UDP"
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Host string // name or ip of egress interface
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Port uint16 // network port number
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Params Params // params like branch, received, rport, etc.
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Next *Via // pointer to next via header if any
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}
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func (via *Via) Append(b *bytes.Buffer) error {
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if via.Host == "" {
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return ViaProtoBlank
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}
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if via.Protocol == "" {
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b.WriteString("SIP/")
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} else {
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b.WriteString(via.Protocol)
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b.WriteString("/")
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}
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if via.Version == "" {
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b.WriteString("2.0/")
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} else {
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b.WriteString(via.Version)
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b.WriteString("/")
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}
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if via.Transport == "" {
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b.WriteString("UDP ")
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} else {
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b.WriteString(via.Transport)
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b.WriteString(" ")
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}
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b.WriteString(via.Host)
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if via.Port != 5060 {
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b.WriteString(":")
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b.WriteString(strconv.Itoa(int(via.Port)))
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}
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via.Params.Append(b)
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return nil
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}
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// Copy returns a deep copy of via.
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func (via *Via) Copy() *Via {
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if via == nil {
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return nil
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}
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res := new(Via)
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res.Protocol = via.Protocol
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res.Version = via.Version
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res.Transport = via.Transport
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res.Host = via.Host
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res.Port = via.Port
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res.Params = via.Params.Copy()
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res.Next = via.Next.Copy()
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return res
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}
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// Branch mutates via with a newly generated branch ID.
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func (via *Via) Branch() *Via {
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via.Params["branch"] = util.GenerateBranch()
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return via
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}
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// Detach returns a shallow copy of via with Next set to nil.
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func (via *Via) Detach() *Via {
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res := new(Via)
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*res = *via
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res.Next = nil
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return res
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}
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// Last returns pointer to last via in linked list.
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func (via *Via) Last() *Via {
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if via != nil {
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for ; via.Next != nil; via = via.Next {
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}
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}
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return via
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}
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func (via *Via) CompareHostPort(other *Via) bool {
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if via != nil && other != nil {
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if via.Host == other.Host &&
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via.Port == other.Port {
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return true
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}
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}
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return false
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}
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func (via *Via) CompareBranch(other *Via) bool {
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if via != nil && other != nil {
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if b1, ok := via.Params["branch"]; ok {
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if b2, ok := other.Params["branch"]; ok {
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if b1 == b2 {
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return true
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}
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}
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}
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}
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return false
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}
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