diff options
Diffstat (limited to 'pkg/tcpip/network/fragmentation/fragmentation.go')
| -rw-r--r-- | pkg/tcpip/network/fragmentation/fragmentation.go | 71 |
1 files changed, 34 insertions, 37 deletions
diff --git a/pkg/tcpip/network/fragmentation/fragmentation.go b/pkg/tcpip/network/fragmentation/fragmentation.go index 936601287..c75ca7d71 100644 --- a/pkg/tcpip/network/fragmentation/fragmentation.go +++ b/pkg/tcpip/network/fragmentation/fragmentation.go @@ -71,16 +71,25 @@ type FragmentID struct { // Fragmentation is the main structure that other modules // of the stack should use to implement IP Fragmentation. type Fragmentation struct { - mu sync.Mutex - highLimit int - lowLimit int - reassemblers map[FragmentID]*reassembler - rList reassemblerList - size int - timeout time.Duration - blockSize uint16 - clock tcpip.Clock - releaseJob *tcpip.Job + mu sync.Mutex + highLimit int + lowLimit int + reassemblers map[FragmentID]*reassembler + rList reassemblerList + size int + timeout time.Duration + blockSize uint16 + clock tcpip.Clock + releaseJob *tcpip.Job + timeoutHandler TimeoutHandler +} + +// TimeoutHandler is consulted if a packet reassembly has timed out. +type TimeoutHandler interface { + // OnReassemblyTimeout will be called with the first fragment (or nil, if the + // first fragment has not been received) of a packet whose reassembly has + // timed out. + OnReassemblyTimeout(pkt *stack.PacketBuffer) } // NewFragmentation creates a new Fragmentation. @@ -97,7 +106,7 @@ type Fragmentation struct { // reassemblingTimeout specifies the maximum time allowed to reassemble a packet. // Fragments are lazily evicted only when a new a packet with an // already existing fragmentation-id arrives after the timeout. -func NewFragmentation(blockSize uint16, highMemoryLimit, lowMemoryLimit int, reassemblingTimeout time.Duration, clock tcpip.Clock) *Fragmentation { +func NewFragmentation(blockSize uint16, highMemoryLimit, lowMemoryLimit int, reassemblingTimeout time.Duration, clock tcpip.Clock, timeoutHandler TimeoutHandler) *Fragmentation { if lowMemoryLimit >= highMemoryLimit { lowMemoryLimit = highMemoryLimit } @@ -111,12 +120,13 @@ func NewFragmentation(blockSize uint16, highMemoryLimit, lowMemoryLimit int, rea } f := &Fragmentation{ - reassemblers: make(map[FragmentID]*reassembler), - highLimit: highMemoryLimit, - lowLimit: lowMemoryLimit, - timeout: reassemblingTimeout, - blockSize: blockSize, - clock: clock, + reassemblers: make(map[FragmentID]*reassembler), + highLimit: highMemoryLimit, + lowLimit: lowMemoryLimit, + timeout: reassemblingTimeout, + blockSize: blockSize, + clock: clock, + timeoutHandler: timeoutHandler, } f.releaseJob = tcpip.NewJob(f.clock, &f.mu, f.releaseReassemblersLocked) @@ -136,16 +146,8 @@ func NewFragmentation(blockSize uint16, highMemoryLimit, lowMemoryLimit int, rea // proto is the protocol number marked in the fragment being processed. It has // to be given here outside of the FragmentID struct because IPv6 should not use // the protocol to identify a fragment. -// -// releaseCB is a callback that will run when the fragment reassembly of a -// packet is complete or cancelled. releaseCB take a a boolean argument which is -// true iff the reassembly is cancelled due to timeout. releaseCB should be -// passed only with the first fragment of a packet. If more than one releaseCB -// are passed for the same packet, only the first releaseCB will be saved for -// the packet and the succeeding ones will be dropped by running them -// immediately with a false argument. func (f *Fragmentation) Process( - id FragmentID, first, last uint16, more bool, proto uint8, vv buffer.VectorisedView, releaseCB func(bool)) ( + id FragmentID, first, last uint16, more bool, proto uint8, pkt *stack.PacketBuffer) ( buffer.VectorisedView, uint8, bool, error) { if first > last { return buffer.VectorisedView{}, 0, false, fmt.Errorf("first=%d is greater than last=%d: %w", first, last, ErrInvalidArgs) @@ -160,10 +162,9 @@ func (f *Fragmentation) Process( return buffer.VectorisedView{}, 0, false, fmt.Errorf("fragment size=%d bytes is not a multiple of block size=%d on non-final fragment: %w", fragmentSize, f.blockSize, ErrInvalidArgs) } - if l := vv.Size(); l < int(fragmentSize) { - return buffer.VectorisedView{}, 0, false, fmt.Errorf("got fragment size=%d bytes less than the expected fragment size=%d bytes (first=%d last=%d): %w", l, fragmentSize, first, last, ErrInvalidArgs) + if l := pkt.Data.Size(); l != int(fragmentSize) { + return buffer.VectorisedView{}, 0, false, fmt.Errorf("got fragment size=%d bytes not equal to the expected fragment size=%d bytes (first=%d last=%d): %w", l, fragmentSize, first, last, ErrInvalidArgs) } - vv.CapLength(int(fragmentSize)) f.mu.Lock() r, ok := f.reassemblers[id] @@ -179,15 +180,9 @@ func (f *Fragmentation) Process( f.releaseReassemblersLocked() } } - if releaseCB != nil { - if !r.setCallback(releaseCB) { - // We got a duplicate callback. Release it immediately. - releaseCB(false /* timedOut */) - } - } f.mu.Unlock() - res, firstFragmentProto, done, consumed, err := r.process(first, last, more, proto, vv) + res, firstFragmentProto, done, consumed, err := r.process(first, last, more, proto, pkt) if err != nil { // We probably got an invalid sequence of fragments. Just // discard the reassembler and move on. @@ -231,7 +226,9 @@ func (f *Fragmentation) release(r *reassembler, timedOut bool) { f.size = 0 } - r.release(timedOut) // releaseCB may run. + if h := f.timeoutHandler; timedOut && h != nil { + h.OnReassemblyTimeout(r.pkt) + } } // releaseReassemblersLocked releases already-expired reassemblers, then |