This commit is contained in:
Arceliar 2021-06-13 05:44:32 -05:00
commit 6c63b02385
2 changed files with 81 additions and 1 deletions

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@ -1,7 +1,7 @@
version: '{build}'
pull_requests:
do_not_increment_build_number: true
os: Visual Studio 2017
os: Visual Studio 2019
shallow_clone: false
environment:

80
src/core/icmpv6.go Normal file
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package core
// The ICMPv6 module implements functions to easily create ICMPv6
// packets. These functions, when mixed with the built-in Go IPv6
// and ICMP libraries, can be used to send control messages back
// to the host. Examples include:
// - NDP messages, when running in TAP mode
// - Packet Too Big messages, when packets exceed the session MTU
// - Destination Unreachable messages, when a session prohibits
// incoming traffic
import (
"encoding/binary"
"net"
"golang.org/x/net/icmp"
"golang.org/x/net/ipv6"
)
type ICMPv6 struct{}
// Marshal returns the binary encoding of h.
func ipv6Header_Marshal(h *ipv6.Header) ([]byte, error) {
b := make([]byte, 40)
b[0] |= byte(h.Version) << 4
b[0] |= byte(h.TrafficClass) >> 4
b[1] |= byte(h.TrafficClass) << 4
b[1] |= byte(h.FlowLabel >> 16)
b[2] = byte(h.FlowLabel >> 8)
b[3] = byte(h.FlowLabel)
binary.BigEndian.PutUint16(b[4:6], uint16(h.PayloadLen))
b[6] = byte(h.NextHeader)
b[7] = byte(h.HopLimit)
copy(b[8:24], h.Src)
copy(b[24:40], h.Dst)
return b, nil
}
// Creates an ICMPv6 packet based on the given icmp.MessageBody and other
// parameters, complete with IP headers only, which can be written directly to
// a TUN adapter, or called directly by the CreateICMPv6L2 function when
// generating a message for TAP adapters.
func CreateICMPv6(dst net.IP, src net.IP, mtype ipv6.ICMPType, mcode int, mbody icmp.MessageBody) ([]byte, error) {
// Create the ICMPv6 message
icmpMessage := icmp.Message{
Type: mtype,
Code: mcode,
Body: mbody,
}
// Convert the ICMPv6 message into []byte
icmpMessageBuf, err := icmpMessage.Marshal(icmp.IPv6PseudoHeader(src, dst))
if err != nil {
return nil, err
}
// Create the IPv6 header
ipv6Header := ipv6.Header{
Version: ipv6.Version,
NextHeader: 58,
PayloadLen: len(icmpMessageBuf),
HopLimit: 255,
Src: src,
Dst: dst,
}
// Convert the IPv6 header into []byte
ipv6HeaderBuf, err := ipv6Header_Marshal(&ipv6Header)
if err != nil {
return nil, err
}
// Construct the packet
responsePacket := make([]byte, ipv6.HeaderLen+ipv6Header.PayloadLen)
copy(responsePacket[:ipv6.HeaderLen], ipv6HeaderBuf)
copy(responsePacket[ipv6.HeaderLen:], icmpMessageBuf)
// Send it back
return responsePacket, nil
}