diff options
| -rw-r--r-- | pkg/tcpip/seqnum/seqnum.go | 5 | ||||
| -rw-r--r-- | pkg/tcpip/transport/tcp/accept.go | 14 | ||||
| -rw-r--r-- | pkg/tcpip/transport/tcp/connect.go | 15 | ||||
| -rw-r--r-- | pkg/tcpip/transport/tcp/endpoint.go | 13 | ||||
| -rw-r--r-- | pkg/tcpip/transport/tcp/rcv.go | 23 | ||||
| -rwxr-xr-x | pkg/tcpip/transport/tcpconntrack/tcp_conntrack.go | 13 |
6 files changed, 40 insertions, 43 deletions
diff --git a/pkg/tcpip/seqnum/seqnum.go b/pkg/tcpip/seqnum/seqnum.go index b40a3c212..d3bea7de4 100644 --- a/pkg/tcpip/seqnum/seqnum.go +++ b/pkg/tcpip/seqnum/seqnum.go @@ -46,11 +46,6 @@ func (v Value) InWindow(first Value, size Size) bool { return v.InRange(first, first.Add(size)) } -// Overlap checks if the window [a,a+b) overlaps with the window [x, x+y). -func Overlap(a Value, b Size, x Value, y Size) bool { - return a.LessThan(x.Add(y)) && x.LessThan(a.Add(b)) -} - // Add calculates the sequence number following the [v, v+s) window. func (v Value) Add(s Size) Value { return v + Value(s) diff --git a/pkg/tcpip/transport/tcp/accept.go b/pkg/tcpip/transport/tcp/accept.go index 5bb243e3b..e6a23c978 100644 --- a/pkg/tcpip/transport/tcp/accept.go +++ b/pkg/tcpip/transport/tcp/accept.go @@ -101,7 +101,7 @@ type listenContext struct { // v6Only is true if listenEP is a dual stack socket and has the // IPV6_V6ONLY option set. - v6only bool + v6Only bool // netProto indicates the network protocol(IPv4/v6) for the listening // endpoint. @@ -126,12 +126,12 @@ func timeStamp() uint32 { } // newListenContext creates a new listen context. -func newListenContext(stk *stack.Stack, listenEP *endpoint, rcvWnd seqnum.Size, v6only bool, netProto tcpip.NetworkProtocolNumber) *listenContext { +func newListenContext(stk *stack.Stack, listenEP *endpoint, rcvWnd seqnum.Size, v6Only bool, netProto tcpip.NetworkProtocolNumber) *listenContext { l := &listenContext{ stack: stk, rcvWnd: rcvWnd, hasher: sha1.New(), - v6only: v6only, + v6Only: v6Only, netProto: netProto, listenEP: listenEP, pendingEndpoints: make(map[stack.TransportEndpointID]*endpoint), @@ -207,7 +207,7 @@ func (l *listenContext) createConnectingEndpoint(s *segment, iss seqnum.Value, i netProto = s.route.NetProto } n := newEndpoint(l.stack, netProto, queue) - n.v6only = l.v6only + n.v6only = l.v6Only n.ID = s.id n.boundNICID = s.route.NICID() n.route = s.route.Clone() @@ -293,7 +293,7 @@ func (l *listenContext) createEndpointAndPerformHandshake(s *segment, opts *head } // Perform the 3-way handshake. - h := newPassiveHandshake(ep, seqnum.Size(ep.initialReceiveWindow()), isn, irs, opts, deferAccept) + h := newPassiveHandshake(ep, ep.rcv.rcvWnd, isn, irs, opts, deferAccept) if err := h.execute(); err != nil { ep.mu.Unlock() ep.Close() @@ -613,8 +613,8 @@ func (e *endpoint) handleListenSegment(ctx *listenContext, s *segment) { // its own goroutine and is responsible for handling connection requests. func (e *endpoint) protocolListenLoop(rcvWnd seqnum.Size) *tcpip.Error { e.mu.Lock() - v6only := e.v6only - ctx := newListenContext(e.stack, e, rcvWnd, v6only, e.NetProto) + v6Only := e.v6only + ctx := newListenContext(e.stack, e, rcvWnd, v6Only, e.NetProto) defer func() { // Mark endpoint as closed. This will prevent goroutines running diff --git a/pkg/tcpip/transport/tcp/connect.go b/pkg/tcpip/transport/tcp/connect.go index 368865911..76e27bf26 100644 --- a/pkg/tcpip/transport/tcp/connect.go +++ b/pkg/tcpip/transport/tcp/connect.go @@ -105,24 +105,11 @@ type handshake struct { } func newHandshake(ep *endpoint, rcvWnd seqnum.Size) handshake { - rcvWndScale := ep.rcvWndScaleForHandshake() - - // Round-down the rcvWnd to a multiple of wndScale. This ensures that the - // window offered in SYN won't be reduced due to the loss of precision if - // window scaling is enabled after the handshake. - rcvWnd = (rcvWnd >> uint8(rcvWndScale)) << uint8(rcvWndScale) - - // Ensure we can always accept at least 1 byte if the scale specified - // was too high for the provided rcvWnd. - if rcvWnd == 0 { - rcvWnd = 1 - } - h := handshake{ ep: ep, active: true, rcvWnd: rcvWnd, - rcvWndScale: int(rcvWndScale), + rcvWndScale: ep.rcvWndScaleForHandshake(), } h.resetState() return h diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go index 7e8def82d..45f2aa78b 100644 --- a/pkg/tcpip/transport/tcp/endpoint.go +++ b/pkg/tcpip/transport/tcp/endpoint.go @@ -1062,6 +1062,19 @@ func (e *endpoint) initialReceiveWindow() int { if rcvWnd > routeWnd { rcvWnd = routeWnd } + rcvWndScale := e.rcvWndScaleForHandshake() + + // Round-down the rcvWnd to a multiple of wndScale. This ensures that the + // window offered in SYN won't be reduced due to the loss of precision if + // window scaling is enabled after the handshake. + rcvWnd = (rcvWnd >> uint8(rcvWndScale)) << uint8(rcvWndScale) + + // Ensure we can always accept at least 1 byte if the scale specified + // was too high for the provided rcvWnd. + if rcvWnd == 0 { + rcvWnd = 1 + } + return rcvWnd } diff --git a/pkg/tcpip/transport/tcp/rcv.go b/pkg/tcpip/transport/tcp/rcv.go index caf8977b3..a4b73b588 100644 --- a/pkg/tcpip/transport/tcp/rcv.go +++ b/pkg/tcpip/transport/tcp/rcv.go @@ -70,13 +70,24 @@ func newReceiver(ep *endpoint, irs seqnum.Value, rcvWnd seqnum.Size, rcvWndScale // acceptable checks if the segment sequence number range is acceptable // according to the table on page 26 of RFC 793. func (r *receiver) acceptable(segSeq seqnum.Value, segLen seqnum.Size) bool { - rcvWnd := r.rcvNxt.Size(r.rcvAcc) - if rcvWnd == 0 { - return segLen == 0 && segSeq == r.rcvNxt - } + return Acceptable(segSeq, segLen, r.rcvNxt, r.rcvAcc) +} - return segSeq.InWindow(r.rcvNxt, rcvWnd) || - seqnum.Overlap(r.rcvNxt, rcvWnd, segSeq, segLen) +// Acceptable checks if a segment that starts at segSeq and has length segLen is +// "acceptable" for arriving in a receive window that starts at rcvNxt and ends +// before rcvAcc, according to the table on page 26 and 69 of RFC 793. +func Acceptable(segSeq seqnum.Value, segLen seqnum.Size, rcvNxt, rcvAcc seqnum.Value) bool { + if rcvNxt == rcvAcc { + return segLen == 0 && segSeq == rcvNxt + } + if segLen == 0 { + // rcvWnd is incremented by 1 because that is Linux's behavior despite the + // RFC. + return segSeq.InRange(rcvNxt, rcvAcc.Add(1)) + } + // Page 70 of RFC 793 allows packets that can be made "acceptable" by trimming + // the payload, so we'll accept any payload that overlaps the receieve window. + return rcvNxt.LessThan(segSeq.Add(segLen)) && segSeq.LessThan(rcvAcc) } // getSendParams returns the parameters needed by the sender when building diff --git a/pkg/tcpip/transport/tcpconntrack/tcp_conntrack.go b/pkg/tcpip/transport/tcpconntrack/tcp_conntrack.go index 93712cd45..30d05200f 100755 --- a/pkg/tcpip/transport/tcpconntrack/tcp_conntrack.go +++ b/pkg/tcpip/transport/tcpconntrack/tcp_conntrack.go @@ -20,6 +20,7 @@ package tcpconntrack import ( "gvisor.dev/gvisor/pkg/tcpip/header" "gvisor.dev/gvisor/pkg/tcpip/seqnum" + "gvisor.dev/gvisor/pkg/tcpip/transport/tcp" ) // Result is returned when the state of a TCB is updated in response to an @@ -311,17 +312,7 @@ type stream struct { // the window is zero, if it's a packet with no payload and sequence number // equal to una. func (s *stream) acceptable(segSeq seqnum.Value, segLen seqnum.Size) bool { - wnd := s.una.Size(s.end) - if wnd == 0 { - return segLen == 0 && segSeq == s.una - } - - // Make sure [segSeq, seqSeq+segLen) is non-empty. - if segLen == 0 { - segLen = 1 - } - - return seqnum.Overlap(s.una, wnd, segSeq, segLen) + return tcp.Acceptable(segSeq, segLen, s.una, s.end) } // closed determines if the stream has already been closed. This happens when |