/
udpHeartbeat.go
104 lines (92 loc) · 2.37 KB
/
udpHeartbeat.go
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package protocol
import (
"encoding/binary"
"errors"
)
const MaxHeartbeatSize = 1400
type AmAliveChunk struct {
ID int
Checksum uint64
}
//AmAlive stores heartbeat information
type AmAlive struct {
KnownChunks []AmAliveChunk //Chunks known by the server
RecentlyAddedServers []string
RecentlyDeadServers []string
}
//Marshal serializes aa into a []byte
func (aa *AmAlive) Marshal() []byte {
//KnownChunks
msg := make([]byte, MaxHeartbeatSize)
binary.LittleEndian.PutUint16(msg[0:], uint16(len(aa.KnownChunks)))
m := msg[2:]
for _, c := range aa.KnownChunks {
binary.LittleEndian.PutUint32(m[:], uint32(c.ID))
binary.LittleEndian.PutUint64(m[4:], c.Checksum)
m = m[12:]
}
//RecentlyAddedServers
for _, addr := range aa.RecentlyAddedServers {
if len(addr)+64 >= len(m[:]) {
break
}
binary.LittleEndian.PutUint16(m, uint16(len([]byte(addr))))
copy(m[2:], addr)
m = m[2+len([]byte(addr)):]
}
binary.LittleEndian.PutUint16(m, 0)
m = m[2:]
//RecentlyDeadServers
for _, addr := range aa.RecentlyDeadServers {
if len(addr)+4 >= len(m[:]) {
break
}
binary.LittleEndian.PutUint16(m[:2], uint16(len([]byte(addr))))
copy(m[2:], addr)
m = m[2+len([]byte(addr)):]
}
binary.LittleEndian.PutUint16(m, 0)
return msg
}
//AmAliveUnMarshal unserializes s into an AmAlive object
func AmAliveUnMarshal(msg []byte) (*AmAlive, error) {
aa := new(AmAlive)
lenKnownChunks := binary.LittleEndian.Uint16(msg)
aa.KnownChunks = make([]AmAliveChunk, 0, lenKnownChunks)
m := msg[2:]
for i := 0; i < int(lenKnownChunks); i++ {
if len(m) < 16 {
return nil, errors.New("Bad formatting, error 1")
}
var chunk AmAliveChunk
chunk.ID = int(binary.LittleEndian.Uint32(m))
chunk.Checksum = binary.LittleEndian.Uint64(m[4:])
aa.KnownChunks = append(aa.KnownChunks, chunk)
m = m[12:]
}
for {
if len(m) < 4 {
return nil, errors.New("Bad formatting, error 2")
}
lenAddr := binary.LittleEndian.Uint16(m)
if lenAddr == 0 {
break
}
addr := string(m[2 : 2+lenAddr])
aa.RecentlyAddedServers = append(aa.RecentlyAddedServers, addr)
m = m[2+lenAddr:]
}
for {
if len(m) < 2 {
return nil, errors.New("Bad formatting, error 3")
}
lenAddr := binary.LittleEndian.Uint16(m)
if lenAddr == 0 {
break
}
addr := string(m[2 : 2+lenAddr])
aa.RecentlyDeadServers = append(aa.RecentlyDeadServers, addr)
m = m[2+lenAddr:]
}
return aa, nil
}