github.com/hxx258456/ccgo@v0.0.5-0.20230213014102-48b35f46f66f/net/icmp/dstunreach.go (about)

     1  // Copyright 2014 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package icmp
     6  
     7  import (
     8  	"github.com/hxx258456/ccgo/net/internal/iana"
     9  	"github.com/hxx258456/ccgo/net/ipv4"
    10  	"github.com/hxx258456/ccgo/net/ipv6"
    11  )
    12  
    13  // A DstUnreach represents an ICMP destination unreachable message
    14  // body.
    15  type DstUnreach struct {
    16  	Data       []byte      // data, known as original datagram field
    17  	Extensions []Extension // extensions
    18  }
    19  
    20  // Len implements the Len method of MessageBody interface.
    21  func (p *DstUnreach) Len(proto int) int {
    22  	if p == nil {
    23  		return 0
    24  	}
    25  	l, _ := multipartMessageBodyDataLen(proto, true, p.Data, p.Extensions)
    26  	return l
    27  }
    28  
    29  // Marshal implements the Marshal method of MessageBody interface.
    30  func (p *DstUnreach) Marshal(proto int) ([]byte, error) {
    31  	var typ Type
    32  	switch proto {
    33  	case iana.ProtocolICMP:
    34  		typ = ipv4.ICMPTypeDestinationUnreachable
    35  	case iana.ProtocolIPv6ICMP:
    36  		typ = ipv6.ICMPTypeDestinationUnreachable
    37  	default:
    38  		return nil, errInvalidProtocol
    39  	}
    40  	if !validExtensions(typ, p.Extensions) {
    41  		return nil, errInvalidExtension
    42  	}
    43  	return marshalMultipartMessageBody(proto, true, p.Data, p.Extensions)
    44  }
    45  
    46  // parseDstUnreach parses b as an ICMP destination unreachable message
    47  // body.
    48  func parseDstUnreach(proto int, typ Type, b []byte) (MessageBody, error) {
    49  	if len(b) < 4 {
    50  		return nil, errMessageTooShort
    51  	}
    52  	p := &DstUnreach{}
    53  	var err error
    54  	p.Data, p.Extensions, err = parseMultipartMessageBody(proto, typ, b)
    55  	if err != nil {
    56  		return nil, err
    57  	}
    58  	return p, nil
    59  }