diff options
Diffstat (limited to 'pkg/tcpip/stack/route.go')
| -rw-r--r-- | pkg/tcpip/stack/route.go | 172 |
1 files changed, 89 insertions, 83 deletions
diff --git a/pkg/tcpip/stack/route.go b/pkg/tcpip/stack/route.go index de5fe6ffe..b0251d0b4 100644 --- a/pkg/tcpip/stack/route.go +++ b/pkg/tcpip/stack/route.go @@ -17,7 +17,6 @@ package stack import ( "fmt" - "gvisor.dev/gvisor/pkg/sleep" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/tcpip/header" @@ -31,24 +30,7 @@ import ( // // TODO(gvisor.dev/issue/4902): Unexpose immutable fields. type Route struct { - // RemoteAddress is the final destination of the route. - RemoteAddress tcpip.Address - - // LocalAddress is the local address where the route starts. - LocalAddress tcpip.Address - - // LocalLinkAddress is the link-layer (MAC) address of the - // where the route starts. - LocalLinkAddress tcpip.LinkAddress - - // NextHop is the next node in the path to the destination. - NextHop tcpip.Address - - // NetProto is the network-layer protocol. - NetProto tcpip.NetworkProtocolNumber - - // Loop controls where WritePacket should send packets. - Loop PacketLooping + routeInfo // localAddressNIC is the interface the address is associated with. // TODO(gvisor.dev/issue/4548): Remove this field once we can query the @@ -78,6 +60,45 @@ type Route struct { linkRes LinkAddressResolver } +type routeInfo struct { + // RemoteAddress is the final destination of the route. + RemoteAddress tcpip.Address + + // LocalAddress is the local address where the route starts. + LocalAddress tcpip.Address + + // LocalLinkAddress is the link-layer (MAC) address of the + // where the route starts. + LocalLinkAddress tcpip.LinkAddress + + // NextHop is the next node in the path to the destination. + NextHop tcpip.Address + + // NetProto is the network-layer protocol. + NetProto tcpip.NetworkProtocolNumber + + // Loop controls where WritePacket should send packets. + Loop PacketLooping +} + +// RouteInfo contains all of Route's exported fields. +type RouteInfo struct { + routeInfo + + // RemoteLinkAddress is the link-layer (MAC) address of the next hop in the + // route. + RemoteLinkAddress tcpip.LinkAddress +} + +// GetFields returns a RouteInfo with all of r's exported fields. This allows +// callers to store the route's fields without retaining a reference to it. +func (r *Route) GetFields() RouteInfo { + return RouteInfo{ + routeInfo: r.routeInfo, + RemoteLinkAddress: r.RemoteLinkAddress(), + } +} + // constructAndValidateRoute validates and initializes a route. It takes // ownership of the provided local address. // @@ -152,13 +173,15 @@ func makeRoute(netProto tcpip.NetworkProtocolNumber, localAddr, remoteAddr tcpip 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, + routeInfo: routeInfo{ + NetProto: netProto, + LocalAddress: localAddr, + LocalLinkAddress: outgoingNIC.LinkEndpoint.LinkAddress(), + RemoteAddress: remoteAddr, + Loop: loop, + }, + localAddressNIC: localAddressNIC, + outgoingNIC: outgoingNIC, } r.mu.Lock() @@ -264,22 +287,21 @@ func (r *Route) ResolveWith(addr tcpip.LinkAddress) { r.mu.remoteLinkAddress = addr } -// Resolve attempts to resolve the link address if necessary. Returns ErrWouldBlock in -// case address resolution requires blocking, e.g. wait for ARP reply. Waker is -// notified when address resolution is complete (success or not). +// Resolve attempts to resolve the link address if necessary. // -// If address resolution is required, ErrNoLinkAddress and a notification channel is -// returned for the top level caller to block. Channel is closed once address resolution -// is complete (success or not). -// -// The NIC r uses must not be locked. -func (r *Route) Resolve(waker *sleep.Waker) (<-chan struct{}, *tcpip.Error) { +// Returns tcpip.ErrWouldBlock if address resolution requires blocking (e.g. +// waiting for ARP reply). If address resolution is required, a notification +// channel is also returned for the caller to block on. The channel is closed +// once address resolution is complete (successful or not). If a callback is +// provided, it will be called when address resolution is complete, regardless +// of success or failure. +func (r *Route) Resolve(afterResolve func()) (<-chan struct{}, *tcpip.Error) { 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. + r.mu.Unlock() return nil, nil } @@ -288,6 +310,7 @@ func (r *Route) Resolve(waker *sleep.Waker) (<-chan struct{}, *tcpip.Error) { // Local link address is already known. if r.RemoteAddress == r.LocalAddress { r.mu.remoteLinkAddress = r.LocalLinkAddress + r.mu.Unlock() return nil, nil } nextAddr = r.RemoteAddress @@ -300,38 +323,36 @@ func (r *Route) Resolve(waker *sleep.Waker) (<-chan struct{}, *tcpip.Error) { linkAddressResolutionRequestLocalAddr = r.LocalAddress } + // Increment the route's reference count because finishResolution retains a + // reference to the route and releases it when called. + r.acquireLocked() + r.mu.Unlock() + + finishResolution := func(linkAddress tcpip.LinkAddress, ok bool) { + if ok { + r.ResolveWith(linkAddress) + } + if afterResolve != nil { + afterResolve() + } + r.Release() + } + if neigh := r.outgoingNIC.neigh; neigh != nil { - entry, ch, err := neigh.entry(nextAddr, linkAddressResolutionRequestLocalAddr, r.linkRes, waker) + _, ch, err := neigh.entry(nextAddr, linkAddressResolutionRequestLocalAddr, r.linkRes, finishResolution) if err != nil { return ch, err } - r.mu.remoteLinkAddress = entry.LinkAddr return nil, nil } - linkAddr, ch, err := r.linkCache.GetLinkAddress(r.outgoingNIC.ID(), nextAddr, linkAddressResolutionRequestLocalAddr, r.NetProto, waker) + _, ch, err := r.linkCache.GetLinkAddress(r.outgoingNIC.ID(), nextAddr, linkAddressResolutionRequestLocalAddr, r.NetProto, finishResolution) if err != nil { return ch, err } - r.mu.remoteLinkAddress = linkAddr return nil, nil } -// RemoveWaker removes a waker that has been added in Resolve(). -func (r *Route) RemoveWaker(waker *sleep.Waker) { - nextAddr := r.NextHop - if nextAddr == "" { - nextAddr = r.RemoteAddress - } - - if neigh := r.outgoingNIC.neigh; neigh != nil { - neigh.removeWaker(nextAddr, waker) - return - } - - r.linkCache.RemoveWaker(r.outgoingNIC.ID(), nextAddr, waker) -} - // local returns true if the route is a local route. func (r *Route) local() bool { return r.Loop == PacketLoop || r.outgoingNIC.IsLoopback() @@ -419,46 +440,31 @@ func (r *Route) MTU() uint32 { return r.outgoingNIC.getNetworkEndpoint(r.NetProto).MTU() } -// Release frees all resources associated with the route. +// Release decrements the reference counter of the resources associated with the +// route. func (r *Route) Release() { r.mu.Lock() defer r.mu.Unlock() - if r.mu.localAddressEndpoint != nil { - r.mu.localAddressEndpoint.DecRef() - r.mu.localAddressEndpoint = nil + if ep := r.mu.localAddressEndpoint; ep != nil { + ep.DecRef() } } -// Clone clones the route. -func (r *Route) Clone() *Route { +// Acquire increments the reference counter of the resources associated with the +// route. +func (r *Route) Acquire() { r.mu.RLock() defer r.mu.RUnlock() + r.acquireLocked() +} - 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, - } - - 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)) +func (r *Route) acquireLocked() { + if ep := r.mu.localAddressEndpoint; ep != nil { + if !ep.IncRef() { + panic(fmt.Sprintf("failed to increment reference count for local address endpoint = %s", r.LocalAddress)) } } - newRoute.mu.remoteLinkAddress = r.mu.remoteLinkAddress - - return newRoute } // Stack returns the instance of the Stack that owns this route. |