diff options
Diffstat (limited to 'pkg/tcpip/stack/route.go')
| -rw-r--r-- | pkg/tcpip/stack/route.go | 200 |
1 files changed, 118 insertions, 82 deletions
diff --git a/pkg/tcpip/stack/route.go b/pkg/tcpip/stack/route.go index 53cb6694f..de5fe6ffe 100644 --- a/pkg/tcpip/stack/route.go +++ b/pkg/tcpip/stack/route.go @@ -18,19 +18,22 @@ import ( "fmt" "gvisor.dev/gvisor/pkg/sleep" + "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/tcpip/header" ) // Route represents a route through the networking stack to a given destination. +// +// It is safe to call Route's methods from multiple goroutines. +// +// The exported fields are immutable. +// +// TODO(gvisor.dev/issue/4902): Unexpose immutable fields. type Route struct { // RemoteAddress is the final destination of the route. RemoteAddress tcpip.Address - // RemoteLinkAddress is the link-layer (MAC) address of the - // final destination of the route. - RemoteLinkAddress tcpip.LinkAddress - // LocalAddress is the local address where the route starts. LocalAddress tcpip.Address @@ -52,8 +55,16 @@ type Route struct { // address's assigned status without the NIC. localAddressNIC *NIC - // localAddressEndpoint is the local address this route is associated with. - localAddressEndpoint AssignableAddressEndpoint + mu struct { + sync.RWMutex + + // localAddressEndpoint is the local address this route is associated with. + localAddressEndpoint AssignableAddressEndpoint + + // remoteLinkAddress is the link-layer (MAC) address of the next hop in the + // route. + remoteLinkAddress tcpip.LinkAddress + } // outgoingNIC is the interface this route uses to write packets. outgoingNIC *NIC @@ -71,22 +82,24 @@ type Route struct { // ownership of the provided local address. // // Returns an empty route if validation fails. -func constructAndValidateRoute(netProto tcpip.NetworkProtocolNumber, addressEndpoint AssignableAddressEndpoint, localAddressNIC, outgoingNIC *NIC, gateway, remoteAddr tcpip.Address, handleLocal, multicastLoop bool) Route { - addrWithPrefix := addressEndpoint.AddressWithPrefix() +func constructAndValidateRoute(netProto tcpip.NetworkProtocolNumber, addressEndpoint AssignableAddressEndpoint, localAddressNIC, outgoingNIC *NIC, gateway, localAddr, remoteAddr tcpip.Address, handleLocal, multicastLoop bool) *Route { + if len(localAddr) == 0 { + localAddr = addressEndpoint.AddressWithPrefix().Address + } - if localAddressNIC != outgoingNIC && header.IsV6LinkLocalAddress(addrWithPrefix.Address) { + if localAddressNIC != outgoingNIC && header.IsV6LinkLocalAddress(localAddr) { addressEndpoint.DecRef() - return Route{} + return nil } // If no remote address is provided, use the local address. if len(remoteAddr) == 0 { - remoteAddr = addrWithPrefix.Address + remoteAddr = localAddr } r := makeRoute( netProto, - addrWithPrefix.Address, + localAddr, remoteAddr, outgoingNIC, localAddressNIC, @@ -99,8 +112,8 @@ func constructAndValidateRoute(netProto tcpip.NetworkProtocolNumber, addressEndp // broadcast it. if len(gateway) > 0 { r.NextHop = gateway - } else if subnet := addrWithPrefix.Subnet(); subnet.IsBroadcast(remoteAddr) { - r.RemoteLinkAddress = header.EthernetBroadcastAddress + } else if subnet := addressEndpoint.Subnet(); subnet.IsBroadcast(remoteAddr) { + r.ResolveWith(header.EthernetBroadcastAddress) } return r @@ -108,11 +121,15 @@ func constructAndValidateRoute(netProto tcpip.NetworkProtocolNumber, addressEndp // makeRoute initializes a new route. It takes ownership of the provided // AssignableAddressEndpoint. -func makeRoute(netProto tcpip.NetworkProtocolNumber, localAddr, remoteAddr tcpip.Address, outgoingNIC, localAddressNIC *NIC, localAddressEndpoint AssignableAddressEndpoint, handleLocal, multicastLoop bool) Route { +func makeRoute(netProto tcpip.NetworkProtocolNumber, localAddr, remoteAddr tcpip.Address, outgoingNIC, localAddressNIC *NIC, localAddressEndpoint AssignableAddressEndpoint, handleLocal, multicastLoop bool) *Route { if localAddressNIC.stack != outgoingNIC.stack { panic(fmt.Sprintf("cannot create a route with NICs from different stacks")) } + if len(localAddr) == 0 { + localAddr = localAddressEndpoint.AddressWithPrefix().Address + } + loop := PacketOut // TODO(gvisor.dev/issue/4689): Loopback interface loops back packets at the @@ -133,18 +150,21 @@ func makeRoute(netProto tcpip.NetworkProtocolNumber, localAddr, remoteAddr tcpip return makeRouteInner(netProto, localAddr, remoteAddr, outgoingNIC, localAddressNIC, localAddressEndpoint, loop) } -func makeRouteInner(netProto tcpip.NetworkProtocolNumber, localAddr, remoteAddr tcpip.Address, outgoingNIC, localAddressNIC *NIC, localAddressEndpoint AssignableAddressEndpoint, loop PacketLooping) Route { - r := Route{ - NetProto: netProto, - LocalAddress: localAddr, - LocalLinkAddress: outgoingNIC.LinkEndpoint.LinkAddress(), - RemoteAddress: remoteAddr, - localAddressNIC: localAddressNIC, - localAddressEndpoint: localAddressEndpoint, - outgoingNIC: outgoingNIC, - Loop: loop, +func makeRouteInner(netProto tcpip.NetworkProtocolNumber, localAddr, remoteAddr tcpip.Address, outgoingNIC, localAddressNIC *NIC, localAddressEndpoint AssignableAddressEndpoint, loop PacketLooping) *Route { + r := &Route{ + NetProto: netProto, + LocalAddress: localAddr, + LocalLinkAddress: outgoingNIC.LinkEndpoint.LinkAddress(), + RemoteAddress: remoteAddr, + localAddressNIC: localAddressNIC, + outgoingNIC: outgoingNIC, + Loop: loop, } + r.mu.Lock() + r.mu.localAddressEndpoint = localAddressEndpoint + r.mu.Unlock() + if r.outgoingNIC.LinkEndpoint.Capabilities()&CapabilityResolutionRequired != 0 { if linkRes, ok := r.outgoingNIC.stack.linkAddrResolvers[r.NetProto]; ok { r.linkRes = linkRes @@ -159,7 +179,7 @@ func makeRouteInner(netProto tcpip.NetworkProtocolNumber, localAddr, remoteAddr // provided AssignableAddressEndpoint. // // A local route is a route to a destination that is local to the stack. -func makeLocalRoute(netProto tcpip.NetworkProtocolNumber, localAddr, remoteAddr tcpip.Address, outgoingNIC, localAddressNIC *NIC, localAddressEndpoint AssignableAddressEndpoint) Route { +func makeLocalRoute(netProto tcpip.NetworkProtocolNumber, localAddr, remoteAddr tcpip.Address, outgoingNIC, localAddressNIC *NIC, localAddressEndpoint AssignableAddressEndpoint) *Route { loop := PacketLoop // TODO(gvisor.dev/issue/4689): Loopback interface loops back packets at the // link endpoint level. We can remove this check once loopback interfaces @@ -170,6 +190,14 @@ func makeLocalRoute(netProto tcpip.NetworkProtocolNumber, localAddr, remoteAddr return makeRouteInner(netProto, localAddr, remoteAddr, outgoingNIC, localAddressNIC, localAddressEndpoint, loop) } +// RemoteLinkAddress returns the link-layer (MAC) address of the next hop in +// the route. +func (r *Route) RemoteLinkAddress() tcpip.LinkAddress { + r.mu.RLock() + defer r.mu.RUnlock() + return r.mu.remoteLinkAddress +} + // NICID returns the id of the NIC from which this route originates. func (r *Route) NICID() tcpip.NICID { return r.outgoingNIC.ID() @@ -231,7 +259,9 @@ func (r *Route) GSOMaxSize() uint32 { // ResolveWith immediately resolves a route with the specified remote link // address. func (r *Route) ResolveWith(addr tcpip.LinkAddress) { - r.RemoteLinkAddress = addr + r.mu.Lock() + defer r.mu.Unlock() + r.mu.remoteLinkAddress = addr } // Resolve attempts to resolve the link address if necessary. Returns ErrWouldBlock in @@ -244,7 +274,10 @@ func (r *Route) ResolveWith(addr tcpip.LinkAddress) { // // The NIC r uses must not be locked. func (r *Route) Resolve(waker *sleep.Waker) (<-chan struct{}, *tcpip.Error) { - if !r.IsResolutionRequired() { + r.mu.Lock() + defer r.mu.Unlock() + + if !r.isResolutionRequiredRLocked() { // Nothing to do if there is no cache (which does the resolution on cache miss) or // link address is already known. return nil, nil @@ -254,7 +287,7 @@ func (r *Route) Resolve(waker *sleep.Waker) (<-chan struct{}, *tcpip.Error) { if nextAddr == "" { // Local link address is already known. if r.RemoteAddress == r.LocalAddress { - r.RemoteLinkAddress = r.LocalLinkAddress + r.mu.remoteLinkAddress = r.LocalLinkAddress return nil, nil } nextAddr = r.RemoteAddress @@ -272,7 +305,7 @@ func (r *Route) Resolve(waker *sleep.Waker) (<-chan struct{}, *tcpip.Error) { if err != nil { return ch, err } - r.RemoteLinkAddress = entry.LinkAddr + r.mu.remoteLinkAddress = entry.LinkAddr return nil, nil } @@ -280,7 +313,7 @@ func (r *Route) Resolve(waker *sleep.Waker) (<-chan struct{}, *tcpip.Error) { if err != nil { return ch, err } - r.RemoteLinkAddress = linkAddr + r.mu.remoteLinkAddress = linkAddr return nil, nil } @@ -309,7 +342,13 @@ func (r *Route) local() bool { // // The NICs the route is associated with must not be locked. func (r *Route) IsResolutionRequired() bool { - if !r.isValidForOutgoing() || r.RemoteLinkAddress != "" || r.local() { + r.mu.RLock() + defer r.mu.RUnlock() + return r.isResolutionRequiredRLocked() +} + +func (r *Route) isResolutionRequiredRLocked() bool { + if !r.isValidForOutgoingRLocked() || r.mu.remoteLinkAddress != "" || r.local() { return false } @@ -317,11 +356,18 @@ func (r *Route) IsResolutionRequired() bool { } func (r *Route) isValidForOutgoing() bool { + r.mu.RLock() + defer r.mu.RUnlock() + return r.isValidForOutgoingRLocked() +} + +func (r *Route) isValidForOutgoingRLocked() bool { if !r.outgoingNIC.Enabled() { return false } - if !r.localAddressNIC.isValidForOutgoing(r.localAddressEndpoint) { + localAddressEndpoint := r.mu.localAddressEndpoint + if localAddressEndpoint == nil || !r.localAddressNIC.isValidForOutgoing(localAddressEndpoint) { return false } @@ -375,37 +421,44 @@ func (r *Route) MTU() uint32 { // Release frees all resources associated with the route. func (r *Route) Release() { - if r.localAddressEndpoint != nil { - r.localAddressEndpoint.DecRef() - r.localAddressEndpoint = nil + r.mu.Lock() + defer r.mu.Unlock() + + if r.mu.localAddressEndpoint != nil { + r.mu.localAddressEndpoint.DecRef() + r.mu.localAddressEndpoint = nil } } // Clone clones the route. -func (r *Route) Clone() Route { - if r.localAddressEndpoint != nil { - if !r.localAddressEndpoint.IncRef() { - panic(fmt.Sprintf("failed to increment reference count for local address endpoint = %s", r.LocalAddress)) - } +func (r *Route) Clone() *Route { + r.mu.RLock() + defer r.mu.RUnlock() + + newRoute := &Route{ + RemoteAddress: r.RemoteAddress, + LocalAddress: r.LocalAddress, + LocalLinkAddress: r.LocalLinkAddress, + NextHop: r.NextHop, + NetProto: r.NetProto, + Loop: r.Loop, + localAddressNIC: r.localAddressNIC, + outgoingNIC: r.outgoingNIC, + linkCache: r.linkCache, + linkRes: r.linkRes, } - return *r -} -// MakeLoopedRoute duplicates the given route with special handling for routes -// used for sending multicast or broadcast packets. In those cases the -// multicast/broadcast address is the remote address when sending out, but for -// incoming (looped) packets it becomes the local address. Similarly, the local -// interface address that was the local address going out becomes the remote -// address coming in. This is different to unicast routes where local and -// remote addresses remain the same as they identify location (local vs remote) -// not direction (source vs destination). -func (r *Route) MakeLoopedRoute() Route { - l := r.Clone() - if r.RemoteAddress == header.IPv4Broadcast || header.IsV4MulticastAddress(r.RemoteAddress) || header.IsV6MulticastAddress(r.RemoteAddress) { - l.RemoteAddress, l.LocalAddress = l.LocalAddress, l.RemoteAddress - l.RemoteLinkAddress = l.LocalLinkAddress + newRoute.mu.Lock() + defer newRoute.mu.Unlock() + newRoute.mu.localAddressEndpoint = r.mu.localAddressEndpoint + if newRoute.mu.localAddressEndpoint != nil { + if !newRoute.mu.localAddressEndpoint.IncRef() { + panic(fmt.Sprintf("failed to increment reference count for local address endpoint = %s", newRoute.LocalAddress)) + } } - return l + newRoute.mu.remoteLinkAddress = r.mu.remoteLinkAddress + + return newRoute } // Stack returns the instance of the Stack that owns this route. @@ -418,7 +471,14 @@ func (r *Route) isV4Broadcast(addr tcpip.Address) bool { return true } - subnet := r.localAddressEndpoint.Subnet() + r.mu.RLock() + localAddressEndpoint := r.mu.localAddressEndpoint + r.mu.RUnlock() + if localAddressEndpoint == nil { + return false + } + + subnet := localAddressEndpoint.Subnet() return subnet.IsBroadcast(addr) } @@ -428,27 +488,3 @@ func (r *Route) IsOutboundBroadcast() bool { // Only IPv4 has a notion of broadcast. return r.isV4Broadcast(r.RemoteAddress) } - -// isInboundBroadcast returns true if the route is for an inbound broadcast -// packet. -func (r *Route) isInboundBroadcast() bool { - // Only IPv4 has a notion of broadcast. - return r.isV4Broadcast(r.LocalAddress) -} - -// ReverseRoute returns new route with given source and destination address. -func (r *Route) ReverseRoute(src tcpip.Address, dst tcpip.Address) Route { - return Route{ - NetProto: r.NetProto, - LocalAddress: dst, - LocalLinkAddress: r.RemoteLinkAddress, - RemoteAddress: src, - RemoteLinkAddress: r.LocalLinkAddress, - Loop: r.Loop, - localAddressNIC: r.localAddressNIC, - localAddressEndpoint: r.localAddressEndpoint, - outgoingNIC: r.outgoingNIC, - linkCache: r.linkCache, - linkRes: r.linkRes, - } -} |