always_inline int
nat44_ed_tcp_is_established (nat44_ed_tcp_state_e state)
{
- static int lookup[] = {
- [NAT44_ED_TCP_STATE_CLOSED] = 0,
- [NAT44_ED_TCP_STATE_SYN_I2O] = 0,
- [NAT44_ED_TCP_STATE_SYN_O2I] = 0,
- [NAT44_ED_TCP_STATE_ESTABLISHED] = 1,
- [NAT44_ED_TCP_STATE_FIN_I2O] = 1,
- [NAT44_ED_TCP_STATE_FIN_O2I] = 1,
- [NAT44_ED_TCP_STATE_RST_TRANS] = 0,
- [NAT44_ED_TCP_STATE_FIN_TRANS] = 0,
- [NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_I2O] = 0,
- [NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_O2I] = 0,
- [NAT44_ED_TCP_N_STATE] = 0,
- };
- ASSERT (state <= ARRAY_LEN (lookup));
- return lookup[state];
+ return state == NAT44_ED_TCP_STATE_ESTABLISHED ? 1 : 0;
}
always_inline u32
s->total_bytes = 0;
}
-always_inline void
-nat44_ed_init_tcp_state_stable (snat_main_t *sm)
-{
- /* first make sure whole table is initialised in a way where state
- * is not changed, then define special cases */
- nat44_ed_tcp_state_e s;
- for (s = 0; s < NAT44_ED_TCP_N_STATE; ++s)
- {
- int i;
- for (i = 0; i < NAT44_ED_N_DIR; ++i)
- {
- int j = 0;
- for (j = 0; j < NAT44_ED_TCP_N_FLAG; ++j)
- {
- sm->tcp_state_change_table[s][i][j] = s;
- }
- }
- }
-
- /* CLOSED and any kind of SYN -> HALF-OPEN */
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_CLOSED][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYN] =
- NAT44_ED_TCP_STATE_SYN_I2O;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_CLOSED][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYN] =
- NAT44_ED_TCP_STATE_SYN_O2I;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_CLOSED][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYNFIN] =
- NAT44_ED_TCP_STATE_SYN_I2O;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_CLOSED][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYNFIN] =
- NAT44_ED_TCP_STATE_SYN_O2I;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_CLOSED][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYNFINRST] =
- NAT44_ED_TCP_STATE_SYN_I2O;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_CLOSED][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYNFINRST] =
- NAT44_ED_TCP_STATE_SYN_O2I;
-
- /* HALF-OPEN and any kind of SYN in right direction -> ESTABLISHED */
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_SYN_I2O][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYN] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_SYN_O2I][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYN] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_SYN_I2O][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYNFIN] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_SYN_O2I][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYNFIN] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_SYN_I2O][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYNFINRST] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_SYN_O2I][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYNFINRST] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
-
- /* ESTABLISHED and any kind of RST -> RST_TRANS */
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_ESTABLISHED][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_RST] =
- NAT44_ED_TCP_STATE_RST_TRANS;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_ESTABLISHED][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_RST] =
- NAT44_ED_TCP_STATE_RST_TRANS;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_ESTABLISHED][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYNRST] =
- NAT44_ED_TCP_STATE_RST_TRANS;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_ESTABLISHED][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYNRST] =
- NAT44_ED_TCP_STATE_RST_TRANS;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_ESTABLISHED][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_FINRST] =
- NAT44_ED_TCP_STATE_RST_TRANS;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_ESTABLISHED][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_FINRST] =
- NAT44_ED_TCP_STATE_RST_TRANS;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_ESTABLISHED][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYNFINRST] =
- NAT44_ED_TCP_STATE_RST_TRANS;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_ESTABLISHED][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYNFINRST] =
- NAT44_ED_TCP_STATE_RST_TRANS;
-
- /* ESTABLISHED and any kind of FIN without RST -> HALF-CLOSED */
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_ESTABLISHED][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_FIN] =
- NAT44_ED_TCP_STATE_FIN_I2O;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_ESTABLISHED][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_FIN] =
- NAT44_ED_TCP_STATE_FIN_O2I;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_ESTABLISHED][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYNFIN] =
- NAT44_ED_TCP_STATE_FIN_I2O;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_ESTABLISHED][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYNFIN] =
- NAT44_ED_TCP_STATE_FIN_O2I;
-
- /* HALF-CLOSED and any kind of FIN -> FIN_TRANS */
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_I2O][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_FIN] =
- NAT44_ED_TCP_STATE_FIN_TRANS;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_O2I][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_FIN] =
- NAT44_ED_TCP_STATE_FIN_TRANS;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_I2O][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYNFIN] =
- NAT44_ED_TCP_STATE_FIN_TRANS;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_O2I][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYNFIN] =
- NAT44_ED_TCP_STATE_FIN_TRANS;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_I2O][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_FINRST] =
- NAT44_ED_TCP_STATE_FIN_TRANS;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_O2I][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_FINRST] =
- NAT44_ED_TCP_STATE_FIN_TRANS;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_I2O][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYNFINRST] =
- NAT44_ED_TCP_STATE_FIN_TRANS;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_O2I][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYNFINRST] =
- NAT44_ED_TCP_STATE_FIN_TRANS;
-
- /* RST_TRANS and anything non-RST -> ESTABLISHED */
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_RST_TRANS][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_NONE] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_RST_TRANS][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_NONE] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_RST_TRANS][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYN] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_RST_TRANS][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYN] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_RST_TRANS][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_FIN] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_RST_TRANS][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_FIN] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_RST_TRANS][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYNFIN] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_RST_TRANS][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYNFIN] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
-
- /* FIN_TRANS and any kind of SYN -> HALF-REOPEN */
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_TRANS][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYN] =
- NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_I2O;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_TRANS][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYN] =
- NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_O2I;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_TRANS][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYNRST] =
- NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_I2O;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_TRANS][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYNRST] =
- NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_O2I;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_TRANS][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYNFIN] =
- NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_I2O;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_TRANS][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYNFIN] =
- NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_O2I;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_TRANS][NAT44_ED_DIR_I2O]
- [NAT44_ED_TCP_FLAG_SYNFINRST] =
- NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_I2O;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_TRANS][NAT44_ED_DIR_O2I]
- [NAT44_ED_TCP_FLAG_SYNFINRST] =
- NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_O2I;
-
- /* HALF-REOPEN and any kind of SYN in right direction -> ESTABLISHED */
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_I2O]
- [NAT44_ED_DIR_O2I][NAT44_ED_TCP_FLAG_SYN] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_O2I]
- [NAT44_ED_DIR_I2O][NAT44_ED_TCP_FLAG_SYN] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_I2O]
- [NAT44_ED_DIR_O2I][NAT44_ED_TCP_FLAG_SYNRST] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_O2I]
- [NAT44_ED_DIR_I2O][NAT44_ED_TCP_FLAG_SYNRST] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_I2O]
- [NAT44_ED_DIR_O2I][NAT44_ED_TCP_FLAG_SYNFIN] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_O2I]
- [NAT44_ED_DIR_I2O][NAT44_ED_TCP_FLAG_SYNFIN] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_I2O]
- [NAT44_ED_DIR_O2I][NAT44_ED_TCP_FLAG_SYNFINRST] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
- sm->tcp_state_change_table[NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_O2I]
- [NAT44_ED_DIR_I2O][NAT44_ED_TCP_FLAG_SYNFINRST] =
- NAT44_ED_TCP_STATE_ESTABLISHED;
-}
-
-/* TCP state tracking according to RFC 7857 (and RFC 6146, which is referenced
- * by RFC 7857). Our implementation also goes beyond by supporting creation of
- * a new session while old session is in transitory timeout after seeing FIN
- * packets from both sides. */
+/*
+ * "Some rise by SYN, and some by virtue FIN" - William Shakespeare
+ * TCP state tracking patterned after RFC 7857 (and RFC 6146, which is
+ * referenced by RFC 7857). In contrast to the state machine in RFC7857 we only
+ * transition to ESTABLISHED state after seeing a full 3-way handshake (SYNs
+ * and ACKs in both directions). RFC7857 as a means of protecting against
+ * spurious RSTs closing a session, goes back to ESTABLISHED if a data packet
+ * is received after the RST. This state machine will leave the state in
+ * transitory if RST is seen. Our implementation also goes beyond by supporting
+ * creation of a new session while old session is in transitory timeout after
+ * seeing FIN packets from both sides.
+ */
always_inline void
nat44_set_tcp_session_state (snat_main_t *sm, f64 now, snat_session_t *ses,
u8 tcp_flags, u32 thread_index,
nat44_ed_dir_e dir)
{
snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
- nat44_ed_tcp_flag_e flags =
- tcp_flags & (TCP_FLAG_SYN | TCP_FLAG_FIN | TCP_FLAG_RST);
+ u8 old_flags = ses->tcp_flags[dir];
+ ses->tcp_flags[dir] |=
+ tcp_flags & (TCP_FLAG_FIN | TCP_FLAG_SYN | TCP_FLAG_RST | TCP_FLAG_ACK);
+ if (old_flags == ses->tcp_flags[dir])
+ return;
u8 old_state = ses->tcp_state;
- ses->tcp_state = sm->tcp_state_change_table[ses->tcp_state][dir][flags];
- if (old_state != ses->tcp_state)
+ switch (old_state)
{
- if (nat44_ed_tcp_is_established (ses->tcp_state))
+ case NAT44_ED_TCP_STATE_CLOSED:
+ // ESTABLISHED when a SYN and ACK is seen from both sides
+ if ((ses->tcp_flags[NAT44_ED_DIR_I2O] &
+ ses->tcp_flags[NAT44_ED_DIR_O2I]) == (TCP_FLAG_SYN | TCP_FLAG_ACK))
{
- if (NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_I2O == old_state ||
- NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_O2I == old_state)
- {
- nat44_ed_session_reopen (thread_index, ses);
- }
+ ses->tcp_state = NAT44_ED_TCP_STATE_ESTABLISHED;
ses->lru_head_index = tsm->tcp_estab_lru_head_index;
}
- else
+ break;
+ case NAT44_ED_TCP_STATE_ESTABLISHED:
+ // CLOSING when a FIN is seen from either side or session has been RST
+ if ((ses->tcp_flags[dir] & TCP_FLAG_FIN) ||
+ (ses->tcp_flags[dir] & TCP_FLAG_RST))
{
- if (NAT44_ED_TCP_STATE_ESTABLISHED == old_state)
- { // need to update last heard otherwise session might get
- // immediately timed out if it has been idle longer than
- // transitory timeout
- ses->last_heard = now;
- }
+ ses->tcp_state = NAT44_ED_TCP_STATE_CLOSING;
+ ses->tcp_flags[NAT44_ED_DIR_I2O] = 0;
+ ses->tcp_flags[NAT44_ED_DIR_O2I] = 0;
+ // need to update last heard otherwise session might get
+ // immediately timed out if it has been idle longer than
+ // transitory timeout
+ ses->last_heard = now;
ses->lru_head_index = tsm->tcp_trans_lru_head_index;
}
- ses->last_lru_update = now;
- clib_dlist_remove (tsm->lru_pool, ses->lru_index);
- clib_dlist_addtail (tsm->lru_pool, ses->lru_head_index, ses->lru_index);
+ break;
+ case NAT44_ED_TCP_STATE_CLOSING:
+ // Allow a transitory session to reopen
+ if ((ses->tcp_flags[NAT44_ED_DIR_I2O] &
+ ses->tcp_flags[NAT44_ED_DIR_O2I]) == (TCP_FLAG_SYN | TCP_FLAG_ACK))
+ {
+ nat44_ed_session_reopen (thread_index, ses);
+ ses->tcp_state = NAT44_ED_TCP_STATE_ESTABLISHED;
+ ses->lru_head_index = tsm->tcp_estab_lru_head_index;
+ }
+ break;
}
+ if (old_state == ses->tcp_state)
+ return;
+ ses->last_lru_update = now;
+ clib_dlist_remove (tsm->lru_pool, ses->lru_index);
+ clib_dlist_addtail (tsm->lru_pool, ses->lru_head_index, ses->lru_index);
}
always_inline void
nat44_session_update_counters (snat_session_t *s, f64 now, uword bytes,
u32 thread_index)
{
- if (NAT44_ED_TCP_STATE_RST_TRANS != s->tcp_state &&
- NAT44_ED_TCP_STATE_FIN_TRANS != s->tcp_state &&
- NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_I2O != s->tcp_state &&
- NAT44_ED_TCP_STATE_FIN_REOPEN_SYN_O2I != s->tcp_state)
- {
- s->last_heard = now;
- }
+ // regardless of TCP state, reset the timer if data packet is seen.
+ s->last_heard = now;
s->total_pkts++;
s->total_bytes += bytes;
}
Code Review / vpp.git / blobdiff