From 48915bdedb346432327986570f28181d48b68567 Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Tue, 29 Sep 2020 00:18:37 -0700 Subject: Move IP state from NIC to NetworkEndpoint/Protocol * Add network address to network endpoints. Hold network-specific state in the NetworkEndpoint instead of the stack. This results in the stack no longer needing to "know" about the network endpoints and special case certain work for various endpoints (e.g. IPv6 DAD). * Provide NetworkEndpoints with an NetworkInterface interface. Instead of just passing the NIC ID of a NIC, pass an interface so the network endpoint may query other information about the NIC such as whether or not it is a loopback device. * Move NDP code and state to the IPv6 package. NDP is IPv6 specific so there is no need for it to live in the stack. * Control forwarding through NetworkProtocols instead of Stack Forwarding should be controlled on a per-network protocol basis so forwarding configurations are now controlled through network protocols. * Remove stack.referencedNetworkEndpoint. Now that addresses are exposed via AddressEndpoint and only one NetworkEndpoint is created per interface, there is no need for a referenced NetworkEndpoint. * Assume network teardown methods are infallible. Fixes #3871, #3916 PiperOrigin-RevId: 334319433 --- pkg/tcpip/network/ipv6/icmp.go | 64 +++++++++++++++++++++++++----------------- 1 file changed, 39 insertions(+), 25 deletions(-) (limited to 'pkg/tcpip/network/ipv6/icmp.go') diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go index dd3295b31..270439b5c 100644 --- a/pkg/tcpip/network/ipv6/icmp.go +++ b/pkg/tcpip/network/ipv6/icmp.go @@ -15,6 +15,8 @@ package ipv6 import ( + "fmt" + "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/tcpip/buffer" "gvisor.dev/gvisor/pkg/tcpip/header" @@ -207,14 +209,7 @@ func (e *endpoint) handleICMP(r *stack.Route, pkt *stack.PacketBuffer, hasFragme return } - s := r.Stack() - if isTentative, err := s.IsAddrTentative(e.nicID, targetAddr); err != nil { - // We will only get an error if the NIC is unrecognized, which should not - // happen. For now, drop this packet. - // - // TODO(b/141002840): Handle this better? - return - } else if isTentative { + if e.hasTentativeAddr(targetAddr) { // If the target address is tentative and the source of the packet is a // unicast (specified) address, then the source of the packet is // attempting to perform address resolution on the target. In this case, @@ -227,7 +222,20 @@ func (e *endpoint) handleICMP(r *stack.Route, pkt *stack.PacketBuffer, hasFragme // stack know so it can handle such a scenario and do nothing further with // the NS. if r.RemoteAddress == header.IPv6Any { - s.DupTentativeAddrDetected(e.nicID, targetAddr) + // We would get an error if the address no longer exists or the address + // is no longer tentative (DAD resolved between the call to + // hasTentativeAddr and this point). Both of these are valid scenarios: + // 1) An address may be removed at any time. + // 2) As per RFC 4862 section 5.4, DAD is not a perfect: + // "Note that the method for detecting duplicates + // is not completely reliable, and it is possible that duplicate + // addresses will still exist" + // + // TODO(gvisor.dev/issue/4046): Handle the scenario when a duplicate + // address is detected for an assigned address. + if err := e.dupTentativeAddrDetected(targetAddr); err != nil && err != tcpip.ErrBadAddress && err != tcpip.ErrInvalidEndpointState { + panic(fmt.Sprintf("unexpected error handling duplicate tentative address: %s", err)) + } } // Do not handle neighbor solicitations targeted to an address that is @@ -240,7 +248,7 @@ func (e *endpoint) handleICMP(r *stack.Route, pkt *stack.PacketBuffer, hasFragme // section 5.4.3. // Is the NS targeting us? - if s.CheckLocalAddress(e.nicID, ProtocolNumber, targetAddr) == 0 { + if r.Stack().CheckLocalAddress(e.NICID(), ProtocolNumber, targetAddr) == 0 { return } @@ -275,7 +283,7 @@ func (e *endpoint) handleICMP(r *stack.Route, pkt *stack.PacketBuffer, hasFragme } else if e.nud != nil { e.nud.HandleProbe(r.RemoteAddress, r.LocalAddress, header.IPv6ProtocolNumber, sourceLinkAddr, e.protocol) } else { - e.linkAddrCache.AddLinkAddress(e.nicID, r.RemoteAddress, sourceLinkAddr) + e.linkAddrCache.AddLinkAddress(e.NICID(), r.RemoteAddress, sourceLinkAddr) } // ICMPv6 Neighbor Solicit messages are always sent to @@ -353,20 +361,26 @@ func (e *endpoint) handleICMP(r *stack.Route, pkt *stack.PacketBuffer, hasFragme // NDP datagrams are very small and ToView() will not incur allocations. na := header.NDPNeighborAdvert(payload.ToView()) targetAddr := na.TargetAddress() - s := r.Stack() - - if isTentative, err := s.IsAddrTentative(e.nicID, targetAddr); err != nil { - // We will only get an error if the NIC is unrecognized, which should not - // happen. For now short-circuit this packet. - // - // TODO(b/141002840): Handle this better? - return - } else if isTentative { + if e.hasTentativeAddr(targetAddr) { // We just got an NA from a node that owns an address we are performing // DAD on, implying the address is not unique. In this case we let the // stack know so it can handle such a scenario and do nothing furthur with // the NDP NA. - s.DupTentativeAddrDetected(e.nicID, targetAddr) + // + // We would get an error if the address no longer exists or the address + // is no longer tentative (DAD resolved between the call to + // hasTentativeAddr and this point). Both of these are valid scenarios: + // 1) An address may be removed at any time. + // 2) As per RFC 4862 section 5.4, DAD is not a perfect: + // "Note that the method for detecting duplicates + // is not completely reliable, and it is possible that duplicate + // addresses will still exist" + // + // TODO(gvisor.dev/issue/4046): Handle the scenario when a duplicate + // address is detected for an assigned address. + if err := e.dupTentativeAddrDetected(targetAddr); err != nil && err != tcpip.ErrBadAddress && err != tcpip.ErrInvalidEndpointState { + panic(fmt.Sprintf("unexpected error handling duplicate tentative address: %s", err)) + } return } @@ -396,7 +410,7 @@ func (e *endpoint) handleICMP(r *stack.Route, pkt *stack.PacketBuffer, hasFragme // address cache with the link address for the target of the message. if len(targetLinkAddr) != 0 { if e.nud == nil { - e.linkAddrCache.AddLinkAddress(e.nicID, targetAddr, targetLinkAddr) + e.linkAddrCache.AddLinkAddress(e.NICID(), targetAddr, targetLinkAddr) return } @@ -568,9 +582,9 @@ func (e *endpoint) handleICMP(r *stack.Route, pkt *stack.PacketBuffer, hasFragme e.nud.HandleProbe(routerAddr, r.LocalAddress, header.IPv6ProtocolNumber, sourceLinkAddr, e.protocol) } - // Tell the NIC to handle the RA. - stack := r.Stack() - stack.HandleNDPRA(e.nicID, routerAddr, ra) + e.mu.Lock() + e.mu.ndp.handleRA(routerAddr, ra) + e.mu.Unlock() case header.ICMPv6RedirectMsg: // TODO(gvisor.dev/issue/2285): Call `e.nud.HandleProbe` after validating -- cgit v1.2.3