Method DeliverLoopback

wgengine/netstack/link_endpoint.go:211–237

DeliverLoopback delivers pkt back into gVisor's network stack as if it arrived from the network, for self-addressed (loopback) packets. It takes ownership of one reference count on pkt. The caller must not use pkt after calling this method. It returns false if the dispatcher is not attached. Outbou

(pkt *stack.PacketBuffer)

// a raw unparsed packet, so we must re-serialize the packet into a new
// PacketBuffer with all bytes in the payload for gVisor to parse on inbound.
func (ep *linkEndpoint) DeliverLoopback(pkt *stack.PacketBuffer) bool {
	ep.mu.RLock()
	d := ep.dispatcher
	ep.mu.RUnlock()
	if d == nil {
		pkt.DecRef()
		return false
	}

	// Serialize the outbound packet back to raw bytes.
	raw := stack.PayloadSince(pkt.NetworkHeader()).AsSlice()
	proto := pkt.NetworkProtocolNumber

	// We're done with the original outbound packet.
	pkt.DecRef()

	// Create a new PacketBuffer from the raw bytes for inbound delivery.
	newPkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
		Payload: buffer.MakeWithData(raw),
	})
	newPkt.NetworkProtocolNumber = proto
	newPkt.RXChecksumValidated = true

	d.DeliverNetworkPacket(proto, newPkt)
	newPkt.DecRef()
	return true
}

// Attach saves the stack network-layer dispatcher for use later when packets
// are injected.