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