From 3789c34b22e7a7466149bfbeedf05bf49188130c Mon Sep 17 00:00:00 2001 From: Bhasker Hariharan Date: Tue, 3 Sep 2019 15:59:58 -0700 Subject: Make UDP traceroute work. Adds support to generate Port Unreachable messages for UDP datagrams received on a port for which there is no valid endpoint. Fixes #703 PiperOrigin-RevId: 267034418 --- pkg/tcpip/header/ipv6.go | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) (limited to 'pkg/tcpip/header/ipv6.go') diff --git a/pkg/tcpip/header/ipv6.go b/pkg/tcpip/header/ipv6.go index bc4e56535..093850e25 100644 --- a/pkg/tcpip/header/ipv6.go +++ b/pkg/tcpip/header/ipv6.go @@ -22,12 +22,14 @@ import ( ) const ( - versTCFL = 0 - payloadLen = 4 - nextHdr = 6 - hopLimit = 7 - v6SrcAddr = 8 - v6DstAddr = v6SrcAddr + IPv6AddressSize + versTCFL = 0 + // IPv6PayloadLenOffset is the offset of the PayloadLength field in + // IPv6 header. + IPv6PayloadLenOffset = 4 + nextHdr = 6 + hopLimit = 7 + v6SrcAddr = 8 + v6DstAddr = v6SrcAddr + IPv6AddressSize ) // IPv6Fields contains the fields of an IPv6 packet. It is used to describe the @@ -94,7 +96,7 @@ var IPv6EmptySubnet = func() tcpip.Subnet { // PayloadLength returns the value of the "payload length" field of the ipv6 // header. func (b IPv6) PayloadLength() uint16 { - return binary.BigEndian.Uint16(b[payloadLen:]) + return binary.BigEndian.Uint16(b[IPv6PayloadLenOffset:]) } // HopLimit returns the value of the "hop limit" field of the ipv6 header. @@ -148,7 +150,7 @@ func (b IPv6) SetTOS(t uint8, l uint32) { // SetPayloadLength sets the "payload length" field of the ipv6 header. func (b IPv6) SetPayloadLength(payloadLength uint16) { - binary.BigEndian.PutUint16(b[payloadLen:], payloadLength) + binary.BigEndian.PutUint16(b[IPv6PayloadLenOffset:], payloadLength) } // SetSourceAddress sets the "source address" field of the ipv6 header. -- cgit v1.2.3