+static_always_inline int
+icmp_get_ed_key(ip4_header_t *ip0, nat_ed_ses_key_t *p_key0)
+{
+ icmp46_header_t *icmp0;
+ nat_ed_ses_key_t key0;
+ icmp_echo_header_t *echo0, *inner_echo0 = 0;
+ ip4_header_t *inner_ip0;
+ void *l4_header = 0;
+ icmp46_header_t *inner_icmp0;
+
+ icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
+ echo0 = (icmp_echo_header_t *)(icmp0+1);
+
+ if (!icmp_is_error_message (icmp0))
+ {
+ key0.proto = IP_PROTOCOL_ICMP;
+ key0.l_addr = ip0->dst_address;
+ key0.r_addr = ip0->src_address;
+ key0.l_port = key0.r_port = echo0->identifier;
+ }
+ else
+ {
+ inner_ip0 = (ip4_header_t *)(echo0+1);
+ l4_header = ip4_next_header (inner_ip0);
+ key0.proto = inner_ip0->protocol;
+ key0.l_addr = inner_ip0->src_address;
+ key0.r_addr = inner_ip0->dst_address;
+ switch (ip_proto_to_snat_proto (inner_ip0->protocol))
+ {
+ case SNAT_PROTOCOL_ICMP:
+ inner_icmp0 = (icmp46_header_t*)l4_header;
+ inner_echo0 = (icmp_echo_header_t *)(inner_icmp0+1);
+ key0.l_port = key0.r_port = inner_echo0->identifier;
+ break;
+ case SNAT_PROTOCOL_UDP:
+ case SNAT_PROTOCOL_TCP:
+ key0.l_port = ((tcp_udp_header_t*)l4_header)->src_port;
+ key0.r_port = ((tcp_udp_header_t*)l4_header)->dst_port;
+ break;
+ default:
+ return -1;
+ }
+ }
+ *p_key0 = key0;
+ return 0;
+}
+
+static int
+next_src_nat (snat_main_t * sm, ip4_header_t * ip, u32 proto, u16 src_port,
+ u32 thread_index)
+{
+ snat_session_key_t key;
+ clib_bihash_kv_8_8_t kv, value;
+
+ key.addr = ip->src_address;
+ key.port = src_port;
+ key.protocol = proto;
+ key.fib_index = sm->inside_fib_index;
+ kv.key = key.as_u64;
+
+ if (!clib_bihash_search_8_8 (&sm->per_thread_data[thread_index].in2out, &kv,
+ &value))
+ return 1;
+
+ return 0;
+}
+
+static void
+create_bypass_for_fwd(snat_main_t * sm, ip4_header_t * ip, u32 rx_fib_index,
+ u32 thread_index)
+{
+ nat_ed_ses_key_t key;
+ clib_bihash_kv_16_8_t kv, value;
+ udp_header_t *udp;
+ snat_user_t *u;
+ snat_session_t *s = 0;
+ snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+
+ if (ip->protocol == IP_PROTOCOL_ICMP)
+ {
+ if (icmp_get_ed_key (ip, &key))
+ return;
+ }
+ else if (ip->protocol == IP_PROTOCOL_UDP || ip->protocol == IP_PROTOCOL_TCP)
+ {
+ udp = ip4_next_header(ip);
+ key.r_addr = ip->src_address;
+ key.l_addr = ip->dst_address;
+ key.proto = ip->protocol;
+ key.l_port = udp->dst_port;
+ key.r_port = udp->src_port;
+ }
+ else
+ {
+ key.r_addr = ip->src_address;
+ key.l_addr = ip->dst_address;
+ key.proto = ip->protocol;
+ key.l_port = key.r_port = 0;
+ }
+ key.fib_index = 0;
+ kv.key[0] = key.as_u64[0];
+ kv.key[1] = key.as_u64[1];
+
+ if (!clib_bihash_search_16_8 (&sm->in2out_ed, &kv, &value))
+ {
+ s = pool_elt_at_index (tsm->sessions, value.value);
+ }
+ else
+ {
+ if (PREDICT_FALSE (maximum_sessions_exceeded(sm, thread_index)))
+ return;
+
+ u = nat_user_get_or_create (sm, &ip->dst_address, sm->inside_fib_index, thread_index);
+ if (!u)
+ {
+ clib_warning ("create NAT user failed");
+ return;
+ }
+
+ s = nat_session_alloc_or_recycle (sm, u, thread_index);
+ if (!s)
+ {
+ clib_warning ("create NAT session failed");
+ return;
+ }
+
+ s->ext_host_addr = key.r_addr;
+ s->ext_host_port = key.r_port;
+ s->flags |= SNAT_SESSION_FLAG_FWD_BYPASS;
+ s->outside_address_index = ~0;
+ s->out2in.addr = key.l_addr;
+ s->out2in.port = key.l_port;
+ s->out2in.protocol = ip_proto_to_snat_proto (key.proto);
+ s->out2in.fib_index = 0;
+ s->in2out = s->out2in;
+ user_session_increment (sm, u, 0);
+
+ kv.value = s - tsm->sessions;
+ if (clib_bihash_add_del_16_8 (&sm->in2out_ed, &kv, 1))
+ clib_warning ("in2out_ed key add failed");
+ }
+
+ if (ip->protocol == IP_PROTOCOL_TCP)
+ {
+ tcp_header_t *tcp = ip4_next_header(ip);
+ nat44_set_tcp_session_state (sm, s, tcp, thread_index);
+ }
+ /* Per-user LRU list maintenance */
+ clib_dlist_remove (tsm->list_pool, s->per_user_index);
+ clib_dlist_addtail (tsm->list_pool, s->per_user_list_head_index,
+ s->per_user_index);
+}
+