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authorFilip Varga <fivarga@cisco.com>2020-02-25 14:31:33 +0100
committerOle Trøan <otroan@employees.org>2020-03-13 11:17:13 +0000
commita73f2d6f53c224668bd6bbea1a980ee4313c794f (patch)
treec40965985639940beb294e8688aedbe30e47a548 /src/plugins/nat/in2out_ed.c
parentc27b43673237c3971c1c170646b531728e0d8eb1 (diff)
nat: timed out session scavenging upgrade
Patch changes the behavior of session scavenging and fixes multiple nat issues. Allows proper session clearing and removes issue with lingering sessions in session db. Patch also updates and fixes CLI/API calls for better readability of session state metrics. Fixes security issue that would allow attacker to reuse timed out session in both directions (in2out/out2in). Type: improvement Signed-off-by: Filip Varga <fivarga@cisco.com> Change-Id: I78897585a2a57291fad5db6d457941aa0a0457bd
Diffstat (limited to 'src/plugins/nat/in2out_ed.c')
-rw-r--r--src/plugins/nat/in2out_ed.c55
1 files changed, 42 insertions, 13 deletions
diff --git a/src/plugins/nat/in2out_ed.c b/src/plugins/nat/in2out_ed.c
index 581d7b4ef60..ca737d56663 100644
--- a/src/plugins/nat/in2out_ed.c
+++ b/src/plugins/nat/in2out_ed.c
@@ -209,14 +209,18 @@ slow_path_ed (snat_main_t * sm,
};
nat44_is_idle_session_ctx_t ctx;
- nat44_session_try_cleanup (&key->l_addr, rx_fib_index, thread_index, now);
+ u32 cleared = 0;
if (PREDICT_FALSE (nat44_maximum_sessions_exceeded (sm, thread_index)))
{
- b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_SESSIONS_EXCEEDED];
- nat_ipfix_logging_max_sessions (thread_index, sm->max_translations);
- nat_elog_notice ("maximum sessions exceeded");
- return NAT_NEXT_DROP;
+ if (PREDICT_FALSE
+ (!(cleared = nat44_users_cleanup (thread_index, now))))
+ {
+ b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_SESSIONS_EXCEEDED];
+ nat_ipfix_logging_max_sessions (thread_index, sm->max_translations);
+ nat_elog_notice ("maximum sessions exceeded");
+ return NAT_NEXT_DROP;
+ }
}
key0.addr = key->l_addr;
@@ -224,6 +228,7 @@ slow_path_ed (snat_main_t * sm,
key1.protocol = key0.protocol = proto;
key0.fib_index = rx_fib_index;
key1.fib_index = sm->outside_fib_index;
+
/* First try to match static mapping by local address and port */
if (snat_static_mapping_match
(sm, key0, &key1, 0, 0, 0, &lb, 0, &identity_nat))
@@ -234,9 +239,16 @@ slow_path_ed (snat_main_t * sm,
sm->port_per_thread,
tsm->snat_thread_index))
{
- nat_elog_notice ("addresses exhausted");
- b->error = node->errors[NAT_IN2OUT_ED_ERROR_OUT_OF_PORTS];
- return NAT_NEXT_DROP;
+ if (cleared || !nat44_out_of_ports_cleanup (thread_index, now) ||
+ snat_alloc_outside_address_and_port (sm->addresses,
+ rx_fib_index, thread_index,
+ &key1, sm->port_per_thread,
+ tsm->snat_thread_index))
+ {
+ nat_elog_notice ("addresses exhausted");
+ b->error = node->errors[NAT_IN2OUT_ED_ERROR_OUT_OF_PORTS];
+ return NAT_NEXT_DROP;
+ }
}
}
else
@@ -246,16 +258,19 @@ slow_path_ed (snat_main_t * sm,
*sessionp = s;
return next;
}
-
is_sm = 1;
}
- if (proto == SNAT_PROTOCOL_TCP)
+ if (PREDICT_TRUE (proto == SNAT_PROTOCOL_TCP))
{
- if (!tcp_flags_is_init
- (vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags))
+ if (PREDICT_FALSE
+ (!tcp_flags_is_init
+ (vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags)))
{
b->error = node->errors[NAT_IN2OUT_ED_ERROR_NON_SYN];
+ if (!is_sm)
+ snat_free_outside_address_and_port (sm->addresses,
+ thread_index, &key1);
return NAT_NEXT_DROP;
}
}
@@ -932,9 +947,23 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t * vm,
next0 = def_slow;
goto trace0;
}
-
s0 = pool_elt_at_index (tsm->sessions, value0.value);
+ // drop if session expired
+ u64 sess_timeout_time;
+ sess_timeout_time = s0->last_heard +
+ (f64) nat44_session_get_timeout (sm, s0);
+ if (now >= sess_timeout_time)
+ {
+ // delete session
+ nat_free_session_data (sm, s0, thread_index, 0);
+ nat44_delete_session (sm, s0, thread_index);
+
+ next0 = NAT_NEXT_DROP;
+ goto trace0;
+ }
+ //
+
b0->flags |= VNET_BUFFER_F_IS_NATED;
if (!is_output_feature)