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authorOle Troan <ot@cisco.com>2022-03-17 11:58:38 +0100
committerOle Tr�an <otroan@employees.org>2022-04-21 10:35:58 +0000
commit5297447bd64ab253ab3ab3e144605dd39f995f12 (patch)
treed351435893287349ebb9ca5736a627ff53cc28f9 /src/plugins/nat/nat44-ed/nat44_ed_format.c
parente0c875551fa0cd49131671be0f521801e06764f8 (diff)
nat: tweak rfc7857 tcp connection tracking
The RFC7857 state machine introduced in 56c492a is a trade-off. It tries to retain sessions as much as possible and also offers some protection against spurious RST by re-establishing sessions if data is received after the RST. From experience in the wild, this algorithm is a little too liberal, as it leaves too many spurious established sessions in the session table. E.g. a oberserved pattern is: client server <- FIN, ACK ACK -> ACK -> RST, ACK -> With the current state machine this would leave the session in established state. These proposed changes do: - require 3-way handshake to establish session. (current requires only to see SYNs from both sides) - RST will move session to transitory without recovery if data is sent after - Only a single FIN is needed to move to transitory Fixes: 56c492aa0502751de2dd9d890096a82c5f04776d Type: fix Signed-off-by: Ole Troan <ot@cisco.com> Change-Id: I92e593e00b2efe48d04997642d85bd59e0eaa2ea Signed-off-by: Ole Troan <ot@cisco.com>
Diffstat (limited to 'src/plugins/nat/nat44-ed/nat44_ed_format.c')
-rw-r--r--src/plugins/nat/nat44-ed/nat44_ed_format.c29
1 files changed, 3 insertions, 26 deletions
diff --git a/src/plugins/nat/nat44-ed/nat44_ed_format.c b/src/plugins/nat/nat44-ed/nat44_ed_format.c
index f643d1c6056..ee3e925e529 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_format.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_format.c
@@ -303,34 +303,11 @@ format_nat44_ed_tcp_state (u8 *s, va_list *args)
case NAT44_ED_TCP_STATE_CLOSED:
s = format (s, "closed");
break;
- case NAT44_ED_TCP_STATE_SYN_I2O:
- s = format (s, "SYN seen in in2out direction");
- break;
- case NAT44_ED_TCP_STATE_SYN_O2I:
- s = format (s, "SYN seen in out2in direction");
- break;
case NAT44_ED_TCP_STATE_ESTABLISHED:
- s = format (s, "SYN seen in both directions/established");
- break;
- case NAT44_ED_TCP_STATE_FIN_I2O:
- s = format (s, "FIN seen in in2out direction");
- break;
- case NAT44_ED_TCP_STATE_FIN_O2I:
- s = format (s, "FIN seen in out2in direction");
- break;
- case NAT44_ED_TCP_STATE_RST_TRANS:
- s = format (s, "RST seen/transitory timeout");
- break;
- case NAT44_ED_TCP_STATE_FIN_TRANS:
- s = format (s, "FIN seen in both directions/transitory timeout");
- break;
- case NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_O2I:
- s = format (s, "FIN seen in both directions/transitory timeout/session "
- "reopening in out2in direction");
+ s = format (s, "established");
break;
- case NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_I2O:
- s = format (s, "FIN seen in both directions/transitory timeout/session "
- "reopening in in2out direction");
+ case NAT44_ED_TCP_STATE_CLOSING:
+ s = format (s, "closing");
break;
case NAT44_ED_TCP_N_STATE:
s = format (s, "BUG! unexpected N_STATE! BUG!");