64 lines
1.4 KiB
Go
64 lines
1.4 KiB
Go
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package stun
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import "errors"
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// UnknownAttributes represents UNKNOWN-ATTRIBUTES attribute.
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//
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// RFC 5389 Section 15.9
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type UnknownAttributes []AttrType
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func (a UnknownAttributes) String() string {
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s := ""
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if len(a) == 0 {
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return "<nil>"
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}
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last := len(a) - 1
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for i, t := range a {
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s += t.String()
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if i != last {
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s += ", "
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}
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}
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return s
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}
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// type size is 16 bit.
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const attrTypeSize = 4
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// AddTo adds UNKNOWN-ATTRIBUTES attribute to message.
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func (a UnknownAttributes) AddTo(m *Message) error {
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v := make([]byte, 0, attrTypeSize*20) // 20 should be enough
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// If len(a.Types) > 20, there will be allocations.
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for i, t := range a {
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v = append(v, 0, 0, 0, 0) // 4 times by 0 (16 bits)
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first := attrTypeSize * i
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last := first + attrTypeSize
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bin.PutUint16(v[first:last], t.Value())
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}
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m.Add(AttrUnknownAttributes, v)
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return nil
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}
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// ErrBadUnknownAttrsSize means that UNKNOWN-ATTRIBUTES attribute value
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// has invalid length.
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var ErrBadUnknownAttrsSize = errors.New("bad UNKNOWN-ATTRIBUTES size")
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// GetFrom parses UNKNOWN-ATTRIBUTES from message.
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func (a *UnknownAttributes) GetFrom(m *Message) error {
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v, err := m.Get(AttrUnknownAttributes)
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if err != nil {
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return err
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}
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if len(v)%attrTypeSize != 0 {
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return ErrBadUnknownAttrsSize
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}
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*a = (*a)[:0]
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first := 0
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for first < len(v) {
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last := first + attrTypeSize
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*a = append(*a, AttrType(bin.Uint16(v[first:last])))
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first = last
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}
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return nil
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}
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