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authorKlement Sekera <ksekera@cisco.com>2022-01-10 21:57:27 +0000
committerOle Tr�an <otroan@employees.org>2022-01-24 12:59:46 +0000
commit56c492aa0502751de2dd9d890096a82c5f04776d (patch)
treea2b8a1c300853070b26f9953a10bd1a4e41f3bdd /src/plugins/nat/nat44-ed/nat44_ed_in2out.c
parent4634d02501235d3803a17839eeaf076110abcb18 (diff)
nat: TCP state tracking based on RFC 7857/RFC 6146
Implement proper state machine based on above RFCs. ACKs to SYNs/FINs are no longer required/tracked. This is more friendly to peers and accounts for lost packets and retransmits. This change also means that all traffic is translated and forwarded while in transitory timeout, which helps delivering e.g. retransmitted FINs, FINACKs and other messages. Also support reopening a session in transitory timeout after seeing both FINs by seeing both SYNs again. This helps quick connection reestablishment if the peers want to. Type: improvement Signed-off-by: Klement Sekera <ksekera@cisco.com> Signed-off-by: Miklos Tirpak <miklos.tirpak@gmail.com> Change-Id: Ibf521c79463472db97e593bfa02b32b4a06dfd2a
Diffstat (limited to 'src/plugins/nat/nat44-ed/nat44_ed_in2out.c')
-rw-r--r--src/plugins/nat/nat44-ed/nat44_ed_in2out.c57
1 files changed, 21 insertions, 36 deletions
diff --git a/src/plugins/nat/nat44-ed/nat44_ed_in2out.c b/src/plugins/nat/nat44-ed/nat44_ed_in2out.c
index 23e0957dabe..99db6010783 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_in2out.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_in2out.c
@@ -49,6 +49,7 @@ typedef struct
u8 is_slow_path;
u8 translation_via_i2of;
u8 lookup_skipped;
+ u8 tcp_state;
} nat_in2out_ed_trace_t;
static u8 *
@@ -78,7 +79,7 @@ format_nat_in2out_ed_trace (u8 * s, va_list * args)
{
if (t->lookup_skipped)
{
- s = format (s, "\n lookup skipped - cached session index used");
+ s = format (s, "\n lookup skipped - cached session index used");
}
else
{
@@ -86,6 +87,11 @@ format_nat_in2out_ed_trace (u8 * s, va_list * args)
&t->search_key);
}
}
+ if (IP_PROTOCOL_TCP == t->i2of.match.proto)
+ {
+ s = format (s, "\n TCP state: %U", format_nat44_ed_tcp_state,
+ t->tcp_state);
+ }
return s;
}
@@ -675,7 +681,9 @@ nat_not_translate_output_feature_fwd (snat_main_t * sm, ip4_header_t * ip,
{
if (ip->protocol == IP_PROTOCOL_TCP)
{
- nat44_set_tcp_session_state_i2o (sm, now, s, b, thread_index);
+ nat44_set_tcp_session_state_i2o (
+ sm, now, s, vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags,
+ thread_index);
}
/* Accounting */
nat44_session_update_counters (s, now,
@@ -697,7 +705,7 @@ nat44_ed_not_translate_output_feature (snat_main_t *sm, vlib_buffer_t *b,
ip4_header_t *ip, u16 src_port,
u16 dst_port, u32 thread_index,
u32 rx_sw_if_index, u32 tx_sw_if_index,
- f64 now, int is_multi_worker)
+ int is_multi_worker)
{
clib_bihash_kv_16_8_t kv, value;
snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
@@ -715,12 +723,6 @@ nat44_ed_not_translate_output_feature (snat_main_t *sm, vlib_buffer_t *b,
s =
pool_elt_at_index (tsm->sessions,
ed_value_get_session_index (&value));
- if (nat44_is_ses_closed (s)
- && (!s->tcp_closed_timestamp || now >= s->tcp_closed_timestamp))
- {
- nat44_ed_free_session_data (sm, s, thread_index, 0);
- nat_ed_session_delete (sm, s, thread_index, 1);
- }
return 1;
}
@@ -800,7 +802,7 @@ icmp_in2out_ed_slow_path (snat_main_t *sm, vlib_buffer_t *b, ip4_header_t *ip,
{
if (PREDICT_FALSE (nat44_ed_not_translate_output_feature (
sm, b, ip, lookup_sport, lookup_dport, thread_index, sw_if_index,
- tx_sw_if_index, now, is_multi_worker)))
+ tx_sw_if_index, is_multi_worker)))
{
return next;
}
@@ -1173,22 +1175,6 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
goto trace0;
}
- if (s0->tcp_closed_timestamp)
- {
- if (now >= s0->tcp_closed_timestamp)
- {
- // session is closed, go slow path, freed in slow path
- next[0] = def_slow;
- }
- else
- {
- // session in transitory timeout, drop
- b0->error = node->errors[NAT_IN2OUT_ED_ERROR_TCP_CLOSED];
- next[0] = NAT_NEXT_DROP;
- }
- goto trace0;
- }
-
// drop if session expired
u64 sess_timeout_time;
sess_timeout_time =
@@ -1239,7 +1225,9 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
case IP_PROTOCOL_TCP:
vlib_increment_simple_counter (&sm->counters.fastpath.in2out.tcp,
thread_index, cntr_sw_if_index0, 1);
- nat44_set_tcp_session_state_i2o (sm, now, s0, b0, thread_index);
+ nat44_set_tcp_session_state_i2o (
+ sm, now, s0, vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags,
+ thread_index);
break;
case IP_PROTOCOL_UDP:
vlib_increment_simple_counter (&sm->counters.fastpath.in2out.udp,
@@ -1282,6 +1270,7 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
clib_memcpy (&t->i2of, &s0->i2o, sizeof (t->i2of));
clib_memcpy (&t->o2if, &s0->o2i, sizeof (t->o2if));
t->translation_via_i2of = (&s0->i2o == f);
+ t->tcp_state = s0->tcp_state;
}
else
{
@@ -1426,13 +1415,6 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
s0 =
pool_elt_at_index (tsm->sessions,
ed_value_get_session_index (&value0));
-
- if (s0->tcp_closed_timestamp && now >= s0->tcp_closed_timestamp)
- {
- nat44_ed_free_session_data (sm, s0, thread_index, 0);
- nat_ed_session_delete (sm, s0, thread_index, 1);
- s0 = NULL;
- }
}
if (!s0)
@@ -1442,7 +1424,7 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
if (PREDICT_FALSE (nat44_ed_not_translate_output_feature (
sm, b0, ip0, vnet_buffer (b0)->ip.reass.l4_src_port,
vnet_buffer (b0)->ip.reass.l4_dst_port, thread_index,
- rx_sw_if_index0, tx_sw_if_index0, now, is_multi_worker)))
+ rx_sw_if_index0, tx_sw_if_index0, is_multi_worker)))
goto trace0;
/*
@@ -1496,7 +1478,9 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
{
vlib_increment_simple_counter (&sm->counters.slowpath.in2out.tcp,
thread_index, cntr_sw_if_index0, 1);
- nat44_set_tcp_session_state_i2o (sm, now, s0, b0, thread_index);
+ nat44_set_tcp_session_state_i2o (
+ sm, now, s0, vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags,
+ thread_index);
}
else
{
@@ -1529,6 +1513,7 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
clib_memcpy (&t->i2of, &s0->i2o, sizeof (t->i2of));
clib_memcpy (&t->o2if, &s0->o2i, sizeof (t->o2if));
t->translation_via_i2of = 1;
+ t->tcp_state = s0->tcp_state;
}
else