From a551add5d8a5bf631cd9859c761e579fdb33ec82 Mon Sep 17 00:00:00 2001 From: Kevin Krakauer Date: Mon, 13 Apr 2020 17:37:21 -0700 Subject: Remove View.First() and View.RemoveFirst() These methods let users eaily break the VectorisedView abstraction, and allowed netstack to slip into pseudo-enforcement of the "all headers are in the first View" invariant. Removing them and replacing with PullUp(n) breaks this reliance and will make it easier to add iptables support and rework network buffer management. The new View.PullUp(n) method is low cost in the common case, when when all the headers fit in the first View. --- pkg/tcpip/network/ipv4/icmp.go | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) (limited to 'pkg/tcpip/network/ipv4/icmp.go') diff --git a/pkg/tcpip/network/ipv4/icmp.go b/pkg/tcpip/network/ipv4/icmp.go index c4bf1ba5c..4cbefe5ab 100644 --- a/pkg/tcpip/network/ipv4/icmp.go +++ b/pkg/tcpip/network/ipv4/icmp.go @@ -25,7 +25,11 @@ import ( // used to find out which transport endpoint must be notified about the ICMP // packet. func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt stack.PacketBuffer) { - h := header.IPv4(pkt.Data.First()) + h, ok := pkt.Data.PullUp(header.IPv4MinimumSize) + if !ok { + return + } + hdr := header.IPv4(h) // We don't use IsValid() here because ICMP only requires that the IP // header plus 8 bytes of the transport header be included. So it's @@ -34,12 +38,12 @@ func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt stack. // // Drop packet if it doesn't have the basic IPv4 header or if the // original source address doesn't match the endpoint's address. - if len(h) < header.IPv4MinimumSize || h.SourceAddress() != e.id.LocalAddress { + if hdr.SourceAddress() != e.id.LocalAddress { return } - hlen := int(h.HeaderLength()) - if pkt.Data.Size() < hlen || h.FragmentOffset() != 0 { + hlen := int(hdr.HeaderLength()) + if pkt.Data.Size() < hlen || hdr.FragmentOffset() != 0 { // We won't be able to handle this if it doesn't contain the // full IPv4 header, or if it's a fragment not at offset 0 // (because it won't have the transport header). @@ -48,15 +52,15 @@ func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt stack. // Skip the ip header, then deliver control message. pkt.Data.TrimFront(hlen) - p := h.TransportProtocol() - e.dispatcher.DeliverTransportControlPacket(e.id.LocalAddress, h.DestinationAddress(), ProtocolNumber, p, typ, extra, pkt) + p := hdr.TransportProtocol() + e.dispatcher.DeliverTransportControlPacket(e.id.LocalAddress, hdr.DestinationAddress(), ProtocolNumber, p, typ, extra, pkt) } func (e *endpoint) handleICMP(r *stack.Route, pkt stack.PacketBuffer) { stats := r.Stats() received := stats.ICMP.V4PacketsReceived - v := pkt.Data.First() - if len(v) < header.ICMPv4MinimumSize { + v, ok := pkt.Data.PullUp(header.ICMPv4MinimumSize) + if !ok { received.Invalid.Increment() return } -- cgit v1.2.3