neo-go/pkg/network/payload/headers.go

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package payload
import (
"errors"
"fmt"
"github.com/nspcc-dev/neo-go/pkg/core/block"
"github.com/nspcc-dev/neo-go/pkg/io"
)
2019-10-22 14:56:03 +00:00
// Headers payload.
type Headers struct {
Hdrs []*block.Header
}
// Users can at most request 2k headers.
const (
MaxHeadersAllowed = 2000
)
// ErrTooManyHeaders is an error returned when too many headers have been received.
var ErrTooManyHeaders = fmt.Errorf("too many headers were received (max: %d)", MaxHeadersAllowed)
// ErrNoHeaders is returned for zero-elements Headers payload which is considered to be invalid.
var ErrNoHeaders = errors.New("no headers (zero length array)")
// DecodeBinary implements the Serializable interface.
func (p *Headers) DecodeBinary(br *io.BinReader) {
lenHeaders := br.ReadVarUint()
if br.Err == nil && lenHeaders == 0 {
br.Err = ErrNoHeaders
return
}
var limitExceeded bool
// C# node does it silently
if limitExceeded = lenHeaders > MaxHeadersAllowed; limitExceeded {
lenHeaders = MaxHeadersAllowed
}
p.Hdrs = make([]*block.Header, lenHeaders)
for i := 0; i < int(lenHeaders); i++ {
header := &block.Header{}
header.DecodeBinary(br)
p.Hdrs[i] = header
}
if br.Err == nil && limitExceeded {
br.Err = ErrTooManyHeaders
}
}
// EncodeBinary implements the Serializable interface.
func (p *Headers) EncodeBinary(bw *io.BinWriter) {
bw.WriteArray(p.Hdrs)
}