94 lines
2.9 KiB
Go
94 lines
2.9 KiB
Go
package sctp
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import (
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"errors"
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"fmt"
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)
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/*
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chunkHeartbeatAck represents an SCTP Chunk of type HEARTBEAT ACK
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An endpoint should send this chunk to its peer endpoint as a response
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to a HEARTBEAT chunk (see Section 8.3). A HEARTBEAT ACK is always
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sent to the source IP address of the IP datagram containing the
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HEARTBEAT chunk to which this ack is responding.
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The parameter field contains a variable-length opaque data structure.
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0 1 2 3
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Type = 5 | Chunk Flags | Heartbeat Ack Length |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Heartbeat Information TLV (Variable-Length) |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Defined as a variable-length parameter using the format described
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in Section 3.2.1, i.e.:
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Variable Parameters Status Type Value
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-------------------------------------------------------------
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Heartbeat Info Mandatory 1
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*/
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type chunkHeartbeatAck struct {
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chunkHeader
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params []param
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}
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var (
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errUnimplemented = errors.New("unimplemented")
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errHeartbeatAckParams = errors.New("heartbeat Ack must have one param")
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errHeartbeatAckNotHeartbeatInfo = errors.New("heartbeat Ack must have one param, and it should be a HeartbeatInfo")
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errHeartbeatAckMarshalParam = errors.New("unable to marshal parameter for Heartbeat Ack")
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)
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func (h *chunkHeartbeatAck) unmarshal(raw []byte) error {
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return errUnimplemented
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}
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func (h *chunkHeartbeatAck) marshal() ([]byte, error) {
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if len(h.params) != 1 {
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return nil, errHeartbeatAckParams
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}
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switch h.params[0].(type) {
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case *paramHeartbeatInfo:
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// ParamHeartbeatInfo is valid
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default:
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return nil, errHeartbeatAckNotHeartbeatInfo
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}
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out := make([]byte, 0)
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for idx, p := range h.params {
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pp, err := p.marshal()
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if err != nil {
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return nil, fmt.Errorf("%w: %v", errHeartbeatAckMarshalParam, err)
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}
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out = append(out, pp...)
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// Chunks (including Type, Length, and Value fields) are padded out
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// by the sender with all zero bytes to be a multiple of 4 bytes
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// long. This padding MUST NOT be more than 3 bytes in total. The
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// Chunk Length value does not include terminating padding of the
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// chunk. *However, it does include padding of any variable-length
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// parameter except the last parameter in the chunk.* The receiver
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// MUST ignore the padding.
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if idx != len(h.params)-1 {
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out = padByte(out, getPadding(len(pp)))
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}
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}
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h.chunkHeader.typ = ctHeartbeatAck
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h.chunkHeader.raw = out
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return h.chunkHeader.marshal()
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}
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func (h *chunkHeartbeatAck) check() (abort bool, err error) {
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return false, nil
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}
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