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authorMatus Fabian <matfabia@cisco.com>2017-08-15 06:59:19 -0700
committerOle Trøan <otroan@employees.org>2017-11-07 21:58:31 +0000
commitefcd1e9e1d7dda4e4ea3db5750925cd8f6894f4d (patch)
tree63c07cf6a94820a5fb2c3935082b6a02f6d210d3 /src/plugins/nat/out2in.c
parent20ab0a4943f7509f6e07d6c614eee90c80c8b963 (diff)
SNAT: IP fragmentation (VPP-890)
Translation of fragmented packets. Change-Id: I9b1f2e9433ce273638080f32c2d3bff39c49899d Signed-off-by: Matus Fabian <matfabia@cisco.com>
Diffstat (limited to 'src/plugins/nat/out2in.c')
-rwxr-xr-xsrc/plugins/nat/out2in.c336
1 files changed, 334 insertions, 2 deletions
diff --git a/src/plugins/nat/out2in.c b/src/plugins/nat/out2in.c
index f250136b86e..489afadb4a2 100755
--- a/src/plugins/nat/out2in.c
+++ b/src/plugins/nat/out2in.c
@@ -25,6 +25,7 @@
#include <nat/nat.h>
#include <nat/nat_ipfix_logging.h>
#include <nat/nat_det.h>
+#include <nat/nat_reass.h>
#include <vppinfra/hash.h>
#include <vppinfra/error.h>
@@ -78,17 +79,40 @@ static u8 * format_snat_out2in_worker_handoff_trace (u8 * s, va_list * args)
return s;
}
+typedef struct {
+ u32 sw_if_index;
+ u32 next_index;
+ u8 cached;
+} nat44_out2in_reass_trace_t;
+
+static u8 * format_nat44_out2in_reass_trace (u8 * s, va_list * args)
+{
+ CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+ CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+ nat44_out2in_reass_trace_t * t = va_arg (*args, nat44_out2in_reass_trace_t *);
+
+ s = format (s, "NAT44_OUT2IN_REASS: sw_if_index %d, next index %d, status %s",
+ t->sw_if_index, t->next_index,
+ t->cached ? "cached" : "translated");
+
+ return s;
+}
+
vlib_node_registration_t snat_out2in_node;
vlib_node_registration_t snat_out2in_fast_node;
vlib_node_registration_t snat_out2in_worker_handoff_node;
vlib_node_registration_t snat_det_out2in_node;
+vlib_node_registration_t nat44_out2in_reass_node;
#define foreach_snat_out2in_error \
_(UNSUPPORTED_PROTOCOL, "Unsupported protocol") \
_(OUT2IN_PACKETS, "Good out2in packets processed") \
_(BAD_ICMP_TYPE, "unsupported ICMP type") \
_(NO_TRANSLATION, "No translation") \
-_(MAX_SESSIONS_EXCEEDED, "Maximum sessions exceeded")
+_(MAX_SESSIONS_EXCEEDED, "Maximum sessions exceeded") \
+_(DROP_FRAGMENT, "Drop fragment") \
+_(MAX_REASS, "Maximum reassemblies exceeded") \
+_(MAX_FRAG, "Maximum fragments per reassembly exceeded")
typedef enum {
#define _(sym,str) SNAT_OUT2IN_ERROR_##sym,
@@ -107,6 +131,7 @@ typedef enum {
SNAT_OUT2IN_NEXT_DROP,
SNAT_OUT2IN_NEXT_LOOKUP,
SNAT_OUT2IN_NEXT_ICMP_ERROR,
+ SNAT_OUT2IN_NEXT_REASS,
SNAT_OUT2IN_N_NEXT,
} snat_out2in_next_t;
@@ -139,6 +164,7 @@ create_session_for_static_mapping (snat_main_t *sm,
dlist_elt_t * per_user_translation_list_elt;
dlist_elt_t * per_user_list_head_elt;
ip4_header_t *ip0;
+ udp_header_t *udp0;
if (PREDICT_FALSE (maximum_sessions_exceeded(sm, thread_index)))
{
@@ -147,6 +173,7 @@ create_session_for_static_mapping (snat_main_t *sm,
}
ip0 = vlib_buffer_get_current (b0);
+ udp0 = ip4_next_header (ip0);
user_key.addr = in2out.addr;
user_key.fib_index = in2out.fib_index;
@@ -188,7 +215,8 @@ create_session_for_static_mapping (snat_main_t *sm,
s->outside_address_index = ~0;
s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
- s->ext_host_addr.as_u32 = ip0->dst_address.as_u32;
+ s->ext_host_addr.as_u32 = ip0->src_address.as_u32;
+ s->ext_host_port = udp0->src_port;
u->nstaticsessions++;
/* Create list elts */
@@ -1033,6 +1061,12 @@ snat_out2in_node_fn (vlib_main_t * vm,
goto trace0;
}
+ if (PREDICT_FALSE (ip4_is_fragment (ip0)))
+ {
+ next0 = SNAT_OUT2IN_NEXT_REASS;
+ goto trace0;
+ }
+
key0.addr = ip0->dst_address;
key0.port = udp0->dst_port;
key0.protocol = proto0;
@@ -1188,6 +1222,12 @@ snat_out2in_node_fn (vlib_main_t * vm,
goto trace1;
}
+ if (PREDICT_FALSE (ip4_is_fragment (ip1)))
+ {
+ next1 = SNAT_OUT2IN_NEXT_REASS;
+ goto trace1;
+ }
+
key1.addr = ip1->dst_address;
key1.port = udp1->dst_port;
key1.protocol = proto1;
@@ -1379,6 +1419,12 @@ snat_out2in_node_fn (vlib_main_t * vm,
goto trace00;
}
+ if (PREDICT_FALSE (ip4_is_fragment (ip0)))
+ {
+ next0 = SNAT_OUT2IN_NEXT_REASS;
+ goto trace00;
+ }
+
key0.addr = ip0->dst_address;
key0.port = udp0->dst_port;
key0.protocol = proto0;
@@ -1530,10 +1576,294 @@ VLIB_REGISTER_NODE (snat_out2in_node) = {
[SNAT_OUT2IN_NEXT_DROP] = "error-drop",
[SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
[SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+ [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
},
};
VLIB_NODE_FUNCTION_MULTIARCH (snat_out2in_node, snat_out2in_node_fn);
+static uword
+nat44_out2in_reass_node_fn (vlib_main_t * vm,
+ vlib_node_runtime_t * node,
+ vlib_frame_t * frame)
+{
+ u32 n_left_from, *from, *to_next;
+ snat_out2in_next_t next_index;
+ u32 pkts_processed = 0;
+ snat_main_t *sm = &snat_main;
+ f64 now = vlib_time_now (vm);
+ u32 thread_index = vlib_get_thread_index ();
+ snat_main_per_thread_data_t *per_thread_data =
+ &sm->per_thread_data[thread_index];
+ u32 *fragments_to_drop = 0;
+ u32 *fragments_to_loopback = 0;
+
+ from = vlib_frame_vector_args (frame);
+ n_left_from = frame->n_vectors;
+ next_index = node->cached_next_index;
+
+ while (n_left_from > 0)
+ {
+ u32 n_left_to_next;
+
+ vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+ while (n_left_from > 0 && n_left_to_next > 0)
+ {
+ u32 bi0, sw_if_index0, proto0, rx_fib_index0, new_addr0, old_addr0;
+ vlib_buffer_t *b0;
+ u32 next0;
+ u8 cached0 = 0;
+ ip4_header_t *ip0;
+ nat_reass_ip4_t *reass0;
+ udp_header_t * udp0;
+ tcp_header_t * tcp0;
+ snat_session_key_t key0, sm0;
+ clib_bihash_kv_8_8_t kv0, value0;
+ snat_session_t * s0 = 0;
+ u16 old_port0, new_port0;
+ ip_csum_t sum0;
+
+ /* speculatively enqueue b0 to the current next frame */
+ bi0 = from[0];
+ to_next[0] = bi0;
+ from += 1;
+ to_next += 1;
+ n_left_from -= 1;
+ n_left_to_next -= 1;
+
+ b0 = vlib_get_buffer (vm, bi0);
+ next0 = SNAT_OUT2IN_NEXT_LOOKUP;
+
+ sw_if_index0 = vnet_buffer(b0)->sw_if_index[VLIB_RX];
+ rx_fib_index0 = fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
+ sw_if_index0);
+
+ if (PREDICT_FALSE (nat_reass_is_drop_frag(0)))
+ {
+ next0 = SNAT_OUT2IN_NEXT_DROP;
+ b0->error = node->errors[SNAT_OUT2IN_ERROR_DROP_FRAGMENT];
+ goto trace0;
+ }
+
+ ip0 = (ip4_header_t *) vlib_buffer_get_current (b0);
+ udp0 = ip4_next_header (ip0);
+ tcp0 = (tcp_header_t *) udp0;
+ proto0 = ip_proto_to_snat_proto (ip0->protocol);
+
+ reass0 = nat_ip4_reass_find_or_create (ip0->src_address,
+ ip0->dst_address,
+ ip0->fragment_id,
+ ip0->protocol,
+ 1,
+ &fragments_to_drop);
+
+ if (PREDICT_FALSE (!reass0))
+ {
+ next0 = SNAT_OUT2IN_NEXT_DROP;
+ b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_REASS];
+ goto trace0;
+ }
+
+ if (PREDICT_FALSE (ip4_is_first_fragment (ip0)))
+ {
+ key0.addr = ip0->dst_address;
+ key0.port = udp0->dst_port;
+ key0.protocol = proto0;
+ key0.fib_index = rx_fib_index0;
+ kv0.key = key0.as_u64;
+
+ if (clib_bihash_search_8_8 (&per_thread_data->out2in, &kv0, &value0))
+ {
+ /* Try to match static mapping by external address and port,
+ destination address and port in packet */
+ if (snat_static_mapping_match(sm, key0, &sm0, 1, 0))
+ {
+ b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
+ /*
+ * Send DHCP packets to the ipv4 stack, or we won't
+ * be able to use dhcp client on the outside interface
+ */
+ if (proto0 != SNAT_PROTOCOL_UDP
+ || (udp0->dst_port
+ != clib_host_to_net_u16(UDP_DST_PORT_dhcp_to_client)))
+
+ next0 = SNAT_OUT2IN_NEXT_DROP;
+ goto trace0;
+ }
+
+ /* Create session initiated by host from external network */
+ s0 = create_session_for_static_mapping(sm, b0, sm0, key0, node,
+ thread_index);
+ if (!s0)
+ {
+ b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
+ next0 = SNAT_OUT2IN_NEXT_DROP;
+ goto trace0;
+ }
+ reass0->sess_index = s0 - per_thread_data->sessions;
+ }
+ else
+ {
+ s0 = pool_elt_at_index (per_thread_data->sessions,
+ value0.value);
+ reass0->sess_index = value0.value;
+ }
+ nat_ip4_reass_get_frags (reass0, &fragments_to_loopback);
+ }
+ else
+ {
+ if (PREDICT_FALSE (reass0->sess_index == (u32) ~0))
+ {
+ if (nat_ip4_reass_add_fragment (reass0, bi0))
+ {
+ b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_FRAG];
+ next0 = SNAT_OUT2IN_NEXT_DROP;
+ goto trace0;
+ }
+ cached0 = 1;
+ goto trace0;
+ }
+ s0 = pool_elt_at_index (per_thread_data->sessions,
+ reass0->sess_index);
+ }
+
+ old_addr0 = ip0->dst_address.as_u32;
+ ip0->dst_address = s0->in2out.addr;
+ new_addr0 = ip0->dst_address.as_u32;
+ vnet_buffer(b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
+
+ sum0 = ip0->checksum;
+ sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
+ ip4_header_t,
+ dst_address /* changed member */);
+ ip0->checksum = ip_csum_fold (sum0);
+
+ if (PREDICT_FALSE (ip4_is_first_fragment (ip0)))
+ {
+ if (PREDICT_TRUE(proto0 == SNAT_PROTOCOL_TCP))
+ {
+ old_port0 = tcp0->dst_port;
+ tcp0->dst_port = s0->in2out.port;
+ new_port0 = tcp0->dst_port;
+
+ sum0 = tcp0->checksum;
+ sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
+ ip4_header_t,
+ dst_address /* changed member */);
+
+ sum0 = ip_csum_update (sum0, old_port0, new_port0,
+ ip4_header_t /* cheat */,
+ length /* changed member */);
+ tcp0->checksum = ip_csum_fold(sum0);
+ }
+ else
+ {
+ old_port0 = udp0->dst_port;
+ udp0->dst_port = s0->in2out.port;
+ udp0->checksum = 0;
+ }
+ }
+
+ /* Accounting */
+ s0->last_heard = now;
+ s0->total_pkts++;
+ s0->total_bytes += vlib_buffer_length_in_chain (vm, b0);
+ /* Per-user LRU list maintenance for dynamic translation */
+ if (!snat_is_session_static (s0))
+ {
+ clib_dlist_remove (sm->per_thread_data[thread_index].list_pool,
+ s0->per_user_index);
+ clib_dlist_addtail (sm->per_thread_data[thread_index].list_pool,
+ s0->per_user_list_head_index,
+ s0->per_user_index);
+ }
+
+ trace0:
+ if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE)
+ && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+ {
+ nat44_out2in_reass_trace_t *t =
+ vlib_add_trace (vm, node, b0, sizeof (*t));
+ t->cached = cached0;
+ t->sw_if_index = sw_if_index0;
+ t->next_index = next0;
+ }
+
+ if (cached0)
+ {
+ n_left_to_next++;
+ to_next--;
+ }
+ else
+ {
+ pkts_processed += next0 != SNAT_OUT2IN_NEXT_DROP;
+
+ /* verify speculative enqueue, maybe switch current next frame */
+ vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+ to_next, n_left_to_next,
+ bi0, next0);
+ }
+
+ if (n_left_from == 0 && vec_len (fragments_to_loopback))
+ {
+ from = vlib_frame_vector_args (frame);
+ u32 len = vec_len (fragments_to_loopback);
+ if (len <= VLIB_FRAME_SIZE)
+ {
+ clib_memcpy (from, fragments_to_loopback, sizeof (u32) * len);
+ n_left_from = len;
+ vec_reset_length (fragments_to_loopback);
+ }
+ else
+ {
+ clib_memcpy (from,
+ fragments_to_loopback + (len - VLIB_FRAME_SIZE),
+ sizeof (u32) * VLIB_FRAME_SIZE);
+ n_left_from = VLIB_FRAME_SIZE;
+ _vec_len (fragments_to_loopback) = len - VLIB_FRAME_SIZE;
+ }
+ }
+ }
+
+ vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+ }
+
+ vlib_node_increment_counter (vm, nat44_out2in_reass_node.index,
+ SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
+ pkts_processed);
+
+ nat_send_all_to_node (vm, fragments_to_drop, node,
+ &node->errors[SNAT_OUT2IN_ERROR_DROP_FRAGMENT],
+ SNAT_OUT2IN_NEXT_DROP);
+
+ vec_free (fragments_to_drop);
+ vec_free (fragments_to_loopback);
+ return frame->n_vectors;
+}
+
+VLIB_REGISTER_NODE (nat44_out2in_reass_node) = {
+ .function = nat44_out2in_reass_node_fn,
+ .name = "nat44-out2in-reass",
+ .vector_size = sizeof (u32),
+ .format_trace = format_nat44_out2in_reass_trace,
+ .type = VLIB_NODE_TYPE_INTERNAL,
+
+ .n_errors = ARRAY_LEN(snat_out2in_error_strings),
+ .error_strings = snat_out2in_error_strings,
+
+ .n_next_nodes = SNAT_OUT2IN_N_NEXT,
+
+ /* edit / add dispositions here */
+ .next_nodes = {
+ [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
+ [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
+ [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+ [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
+ },
+};
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_out2in_reass_node,
+ nat44_out2in_reass_node_fn);
+
/**************************/
/*** deterministic mode ***/
/**************************/
@@ -2017,6 +2347,7 @@ VLIB_REGISTER_NODE (snat_det_out2in_node) = {
[SNAT_OUT2IN_NEXT_DROP] = "error-drop",
[SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
[SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+ [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
},
};
VLIB_NODE_FUNCTION_MULTIARCH (snat_det_out2in_node, snat_det_out2in_node_fn);
@@ -2509,6 +2840,7 @@ VLIB_REGISTER_NODE (snat_out2in_fast_node) = {
[SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
[SNAT_OUT2IN_NEXT_DROP] = "error-drop",
[SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+ [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
},
};
VLIB_NODE_FUNCTION_MULTIARCH (snat_out2in_fast_node, snat_out2in_fast_node_fn);