diff options
-rw-r--r-- | pkg/tcpip/stack/conntrack.go | 4 | ||||
-rw-r--r-- | pkg/tcpip/transport/tcpconntrack/tcp_conntrack.go | 175 |
2 files changed, 90 insertions, 89 deletions
diff --git a/pkg/tcpip/stack/conntrack.go b/pkg/tcpip/stack/conntrack.go index 4a28be585..f5e990f03 100644 --- a/pkg/tcpip/stack/conntrack.go +++ b/pkg/tcpip/stack/conntrack.go @@ -164,9 +164,9 @@ func (cn *conn) updateLocked(pkt *PacketBuffer, reply bool) { } if reply { - cn.tcb.UpdateStateInbound(tcpHeader) + cn.tcb.UpdateStateReply(tcpHeader) } else { - cn.tcb.UpdateStateOutbound(tcpHeader) + cn.tcb.UpdateStateOriginal(tcpHeader) } } diff --git a/pkg/tcpip/transport/tcpconntrack/tcp_conntrack.go b/pkg/tcpip/transport/tcpconntrack/tcp_conntrack.go index 558b06df0..a3ea9e197 100644 --- a/pkg/tcpip/transport/tcpconntrack/tcp_conntrack.go +++ b/pkg/tcpip/transport/tcpconntrack/tcp_conntrack.go @@ -22,8 +22,8 @@ import ( "gvisor.dev/gvisor/pkg/tcpip/seqnum" ) -// Result is returned when the state of a TCB is updated in response to an -// inbound or outbound segment. +// Result is returned when the state of a TCB is updated in response to a +// segment. type Result int const ( @@ -40,24 +40,24 @@ const ( // ResultReset indicates that the connection was reset. ResultReset - // ResultClosedByPeer indicates that the connection was gracefully - // closed, and the inbound stream was closed first. - ResultClosedByPeer + // ResultClosedByResponder indicates that the connection was gracefully + // closed, and the reply stream was closed first. + ResultClosedByResponder - // ResultClosedBySelf indicates that the connection was gracefully - // closed, and the outbound stream was closed first. - ResultClosedBySelf + // ResultClosedByOriginator indicates that the connection was gracefully + // closed, and the original stream was closed first. + ResultClosedByOriginator ) // TCB is a TCP Control Block. It holds state necessary to keep track of a TCP // connection and inform the caller when the connection has been closed. type TCB struct { - inbound stream - outbound stream + reply stream + original stream // State handlers. - handlerInbound func(*TCB, header.TCP) Result - handlerOutbound func(*TCB, header.TCP) Result + handlerReply func(*TCB, header.TCP) Result + handlerOriginal func(*TCB, header.TCP) Result // firstFin holds a pointer to the first stream to send a FIN. firstFin *stream @@ -68,38 +68,38 @@ type TCB struct { // Init initializes the state of the TCB according to the initial SYN. func (t *TCB) Init(initialSyn header.TCP) Result { - t.handlerInbound = synSentStateInbound - t.handlerOutbound = synSentStateOutbound + t.handlerReply = synSentStateReply + t.handlerOriginal = synSentStateOriginal iss := seqnum.Value(initialSyn.SequenceNumber()) - t.outbound.una = iss - t.outbound.nxt = iss.Add(logicalLen(initialSyn)) - t.outbound.end = t.outbound.nxt + t.original.una = iss + t.original.nxt = iss.Add(logicalLen(initialSyn)) + t.original.end = t.original.nxt // Even though "end" is a sequence number, we don't know the initial // receive sequence number yet, so we store the window size until we get - // a SYN from the peer. - t.inbound.una = 0 - t.inbound.nxt = 0 - t.inbound.end = seqnum.Value(initialSyn.WindowSize()) + // a SYN from the server. + t.reply.una = 0 + t.reply.nxt = 0 + t.reply.end = seqnum.Value(initialSyn.WindowSize()) t.state = ResultConnecting return t.state } -// UpdateStateInbound updates the state of the TCB based on the supplied inbound +// UpdateStateReply updates the state of the TCB based on the supplied reply // segment. -func (t *TCB) UpdateStateInbound(tcp header.TCP) Result { - st := t.handlerInbound(t, tcp) +func (t *TCB) UpdateStateReply(tcp header.TCP) Result { + st := t.handlerReply(t, tcp) if st != ResultDrop { t.state = st } return st } -// UpdateStateOutbound updates the state of the TCB based on the supplied -// outbound segment. -func (t *TCB) UpdateStateOutbound(tcp header.TCP) Result { - st := t.handlerOutbound(t, tcp) +// UpdateStateOriginal updates the state of the TCB based on the supplied +// original segment. +func (t *TCB) UpdateStateOriginal(tcp header.TCP) Result { + st := t.handlerOriginal(t, tcp) if st != ResultDrop { t.state = st } @@ -114,46 +114,47 @@ func (t *TCB) State() Result { // IsAlive returns true as long as the connection is established(Alive) // or connecting state. func (t *TCB) IsAlive() bool { - return !t.inbound.rstSeen && !t.outbound.rstSeen && (!t.inbound.closed() || !t.outbound.closed()) + return !t.reply.rstSeen && !t.original.rstSeen && (!t.reply.closed() || !t.original.closed()) } -// OutboundSendSequenceNumber returns the snd.NXT for the outbound stream. -func (t *TCB) OutboundSendSequenceNumber() seqnum.Value { - return t.outbound.nxt +// OriginalSendSequenceNumber returns the snd.NXT for the original stream. +func (t *TCB) OriginalSendSequenceNumber() seqnum.Value { + return t.original.nxt } -// InboundSendSequenceNumber returns the snd.NXT for the inbound stream. -func (t *TCB) InboundSendSequenceNumber() seqnum.Value { - return t.inbound.nxt +// ReplySendSequenceNumber returns the snd.NXT for the reply stream. +func (t *TCB) ReplySendSequenceNumber() seqnum.Value { + return t.reply.nxt } // adapResult modifies the supplied "Result" according to the state of the TCB; // if r is anything other than "Alive", or if one of the streams isn't closed // yet, it is returned unmodified. Otherwise it's converted to either -// ClosedBySelf or ClosedByPeer depending on which stream was closed first. +// ClosedByOriginator or ClosedByResponder depending on which stream was closed +// first. func (t *TCB) adaptResult(r Result) Result { // Check the unmodified case. - if r != ResultAlive || !t.inbound.closed() || !t.outbound.closed() { + if r != ResultAlive || !t.reply.closed() || !t.original.closed() { return r } // Find out which was closed first. - if t.firstFin == &t.outbound { - return ResultClosedBySelf + if t.firstFin == &t.original { + return ResultClosedByOriginator } - return ResultClosedByPeer + return ResultClosedByResponder } -// synSentStateInbound is the state handler for inbound segments when the +// synSentStateReply is the state handler for reply segments when the // connection is in SYN-SENT state. -func synSentStateInbound(t *TCB, tcp header.TCP) Result { +func synSentStateReply(t *TCB, tcp header.TCP) Result { flags := tcp.Flags() ackPresent := flags&header.TCPFlagAck != 0 ack := seqnum.Value(tcp.AckNumber()) // Ignore segment if ack is present but not acceptable. - if ackPresent && !(ack-1).InRange(t.outbound.una, t.outbound.nxt) { + if ackPresent && !(ack-1).InRange(t.original.una, t.original.nxt) { return ResultConnecting } @@ -162,7 +163,7 @@ func synSentStateInbound(t *TCB, tcp header.TCP) Result { // implicitly acceptable). if flags&header.TCPFlagRst != 0 { if ackPresent { - t.inbound.rstSeen = true + t.reply.rstSeen = true return ResultReset } return ResultConnecting @@ -175,62 +176,62 @@ func synSentStateInbound(t *TCB, tcp header.TCP) Result { // Update state informed by this SYN. irs := seqnum.Value(tcp.SequenceNumber()) - t.inbound.una = irs - t.inbound.nxt = irs.Add(logicalLen(tcp)) - t.inbound.end += irs + t.reply.una = irs + t.reply.nxt = irs.Add(logicalLen(tcp)) + t.reply.end += irs - t.outbound.end = t.outbound.una.Add(seqnum.Size(tcp.WindowSize())) + t.original.end = t.original.una.Add(seqnum.Size(tcp.WindowSize())) // If the ACK was set (it is acceptable), update our unacknowledgement // tracking. if ackPresent { - // Advance the "una" and "end" indices of the outbound stream. - if t.outbound.una.LessThan(ack) { - t.outbound.una = ack + // Advance the "una" and "end" indices of the original stream. + if t.original.una.LessThan(ack) { + t.original.una = ack } - if end := ack.Add(seqnum.Size(tcp.WindowSize())); t.outbound.end.LessThan(end) { - t.outbound.end = end + if end := ack.Add(seqnum.Size(tcp.WindowSize())); t.original.end.LessThan(end) { + t.original.end = end } } // Update handlers so that new calls will be handled by new state. - t.handlerInbound = allOtherInbound - t.handlerOutbound = allOtherOutbound + t.handlerReply = allOtherReply + t.handlerOriginal = allOtherOriginal return ResultAlive } -// synSentStateOutbound is the state handler for outbound segments when the +// synSentStateOriginal is the state handler for original segments when the // connection is in SYN-SENT state. -func synSentStateOutbound(t *TCB, tcp header.TCP) Result { - // Drop outbound segments that aren't retransmits of the original one. +func synSentStateOriginal(t *TCB, tcp header.TCP) Result { + // Drop original segments that aren't retransmits of the original one. if tcp.Flags() != header.TCPFlagSyn || - tcp.SequenceNumber() != uint32(t.outbound.una) { + tcp.SequenceNumber() != uint32(t.original.una) { return ResultDrop } // Update the receive window. We only remember the largest value seen. - if wnd := seqnum.Value(tcp.WindowSize()); wnd > t.inbound.end { - t.inbound.end = wnd + if wnd := seqnum.Value(tcp.WindowSize()); wnd > t.reply.end { + t.reply.end = wnd } return ResultConnecting } -// update updates the state of inbound and outbound streams, given the supplied -// inbound segment. For outbound segments, this same function can be called with -// swapped inbound/outbound streams. -func update(tcp header.TCP, inbound, outbound *stream, firstFin **stream) Result { +// update updates the state of reply and original streams, given the supplied +// reply segment. For original segments, this same function can be called with +// swapped reply/original streams. +func update(tcp header.TCP, reply, original *stream, firstFin **stream) Result { // Ignore segments out of the window. s := seqnum.Value(tcp.SequenceNumber()) - if !inbound.acceptable(s, dataLen(tcp)) { + if !reply.acceptable(s, dataLen(tcp)) { return ResultAlive } flags := tcp.Flags() if flags&header.TCPFlagRst != 0 { - inbound.rstSeen = true + reply.rstSeen = true return ResultReset } @@ -242,49 +243,49 @@ func update(tcp header.TCP, inbound, outbound *stream, firstFin **stream) Result // Ignore segments that acknowledge not yet sent data. ack := seqnum.Value(tcp.AckNumber()) - if outbound.nxt.LessThan(ack) { + if original.nxt.LessThan(ack) { return ResultAlive } - // Advance the "una" and "end" indices of the outbound stream. - if outbound.una.LessThan(ack) { - outbound.una = ack + // Advance the "una" and "end" indices of the original stream. + if original.una.LessThan(ack) { + original.una = ack } - if end := ack.Add(seqnum.Size(tcp.WindowSize())); outbound.end.LessThan(end) { - outbound.end = end + if end := ack.Add(seqnum.Size(tcp.WindowSize())); original.end.LessThan(end) { + original.end = end } - // Advance the "nxt" index of the inbound stream. + // Advance the "nxt" index of the reply stream. end := s.Add(logicalLen(tcp)) - if inbound.nxt.LessThan(end) { - inbound.nxt = end + if reply.nxt.LessThan(end) { + reply.nxt = end } // Note the index of the FIN segment. And stash away a pointer to the // first stream to see a FIN. - if flags&header.TCPFlagFin != 0 && !inbound.finSeen { - inbound.finSeen = true - inbound.fin = end - 1 + if flags&header.TCPFlagFin != 0 && !reply.finSeen { + reply.finSeen = true + reply.fin = end - 1 if *firstFin == nil { - *firstFin = inbound + *firstFin = reply } } return ResultAlive } -// allOtherInbound is the state handler for inbound segments in all states +// allOtherReply is the state handler for reply segments in all states // except SYN-SENT. -func allOtherInbound(t *TCB, tcp header.TCP) Result { - return t.adaptResult(update(tcp, &t.inbound, &t.outbound, &t.firstFin)) +func allOtherReply(t *TCB, tcp header.TCP) Result { + return t.adaptResult(update(tcp, &t.reply, &t.original, &t.firstFin)) } -// allOtherOutbound is the state handler for outbound segments in all states +// allOtherOriginal is the state handler for original segments in all states // except SYN-SENT. -func allOtherOutbound(t *TCB, tcp header.TCP) Result { - return t.adaptResult(update(tcp, &t.outbound, &t.inbound, &t.firstFin)) +func allOtherOriginal(t *TCB, tcp header.TCP) Result { + return t.adaptResult(update(tcp, &t.original, &t.reply, &t.firstFin)) } // streams holds the state of a TCP unidirectional stream. @@ -345,7 +346,7 @@ func logicalLen(tcp header.TCP) seqnum.Size { // IsEmpty returns true if tcb is not initialized. func (t *TCB) IsEmpty() bool { - if t.inbound != (stream{}) || t.outbound != (stream{}) { + if t.reply != (stream{}) || t.original != (stream{}) { return false } |