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143 lines
3.0 KiB
143 lines
3.0 KiB
// 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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"strings"
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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 Proto 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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Version string // protocol version e.g. "2.0"
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Proto 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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// Parses a single SIP Via header, provided the part that comes after "Via: ".
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//
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// Via headers are goofy; they're like a URI without a scheme, user, and pass.
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// They tell about the network interfaces a packet traversed to reach us.
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//
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// EBNF: http://sofia-sip.sourceforge.net/refdocs/sip/group__sip__via.html
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func ParseVia(s string) (via *Via, err error) {
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if s[0:4] == "SIP/" {
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s = s[4:]
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if n1 := strings.Index(s, "/"); n1 > 0 {
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if n2 := strings.Index(s, " "); n2 >= n1+3 {
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via = new(Via)
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via.Version = s[0:n1]
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via.Proto = s[n1+1 : n2]
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s, via.Host, via.Port, err = extractHostPort(s[n2+1:])
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if err != nil {
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return nil, err
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}
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if s != "" && s[0] == ';' {
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via.Params = parseParams(s[1:])
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s = ""
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}
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return via, nil
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}
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}
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}
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return nil, ViaBadHeader
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}
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func (via *Via) Append(b *bytes.Buffer) error {
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if via.Version == "" {
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via.Version = "2.0"
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}
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if via.Proto == "" {
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via.Proto = "UDP"
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}
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if via.Port == 0 {
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via.Port = 5060
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}
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if via.Host == "" {
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return ViaProtoBlank
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}
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b.WriteString("SIP/")
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b.WriteString(via.Version)
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b.WriteString("/")
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b.WriteString(via.Proto)
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b.WriteString(" ")
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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.Version = via.Version
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res.Proto = via.Proto
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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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