VPP-598: tcp stack initial commit

Change-Id: I49e5ce0aae6e4ff634024387ceaf7dbc432a0351
Signed-off-by: Dave Barach <dave@barachs.net>
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 542 insertions, 0 deletions

diff --git a/src/vnet/tcp/tcp_syn_filter4.c b/src/vnet/tcp/tcp_syn_filter4.c
new file mode 100644
index 00000000000..c7605a30c98
--- /dev/null
+++ b/src/vnet/tcp/tcp_syn_filter4.c
@@ -0,0 +1,542 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <vnet/pg/pg.h>
+#include <vppinfra/error.h>
+#include <vnet/feature/feature.h>
+#include <vnet/ip/ip.h>
+#include <vppinfra/xxhash.h>
+
+typedef struct
+{
+  f64 next_reset;
+  f64 reset_interval;
+  u8 *syn_counts;
+} syn_filter4_runtime_t;
+
+typedef struct
+{
+  u32 next_index;
+  int not_a_syn;
+  u8 filter_value;
+} syn_filter4_trace_t;
+
+/* packet trace format function */
+static u8 *
+format_syn_filter4_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 *);
+  syn_filter4_trace_t *t = va_arg (*args, syn_filter4_trace_t *);
+
+  s = format (s, "SYN_FILTER4: next index %d, %s",
+	      t->next_index, t->not_a_syn ? "not a syn" : "syn");
+  if (t->not_a_syn == 0)
+    s = format (s, ", filter value %d\n", t->filter_value);
+  else
+    s = format (s, "\n");
+  return s;
+}
+
+static vlib_node_registration_t syn_filter4_node;
+
+#define foreach_syn_filter_error                \
+_(THROTTLED, "TCP SYN packet throttle drops")   \
+_(OK, "TCP SYN packets passed")
+
+typedef enum
+{
+#define _(sym,str) SYN_FILTER_ERROR_##sym,
+  foreach_syn_filter_error
+#undef _
+    SYN_FILTER_N_ERROR,
+} syn_filter_error_t;
+
+static char *syn_filter4_error_strings[] = {
+#define _(sym,string) string,
+  foreach_syn_filter_error
+#undef _
+};
+
+typedef enum
+{
+  SYN_FILTER_NEXT_DROP,
+  SYN_FILTER_N_NEXT,
+} syn_filter_next_t;
+
+extern vnet_feature_arc_registration_t vnet_feat_arc_ip4_local;
+
+static uword
+syn_filter4_node_fn (vlib_main_t * vm,
+		     vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  u32 n_left_from, *from, *to_next;
+  syn_filter_next_t next_index;
+  u32 ok_syn_packets = 0;
+  vnet_feature_main_t *fm = &feature_main;
+  u8 arc_index = vnet_feat_arc_ip4_local.feature_arc_index;
+  vnet_feature_config_main_t *cm = &fm->feature_config_mains[arc_index];
+  syn_filter4_runtime_t *rt = (syn_filter4_runtime_t *) node->runtime_data;
+  f64 now = vlib_time_now (vm);
+  /* Shut up spurious gcc warnings. */
+  u8 *c0 = 0, *c1 = 0, *c2 = 0, *c3 = 0;
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+
+  if (now > rt->next_reset)
+    {
+      memset (rt->syn_counts, 0, vec_len (rt->syn_counts));
+      rt->next_reset = now + rt->reset_interval;
+    }
+
+  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 >= 8 && n_left_to_next >= 4)
+	{
+	  u32 bi0, bi1, bi2, bi3;
+	  vlib_buffer_t *b0, *b1, *b2, *b3;
+	  u32 next0, next1, next2, next3;
+	  ip4_header_t *ip0, *ip1, *ip2, *ip3;
+	  tcp_header_t *tcp0, *tcp1, *tcp2, *tcp3;
+	  u32 not_a_syn0 = 1, not_a_syn1 = 1, not_a_syn2 = 1, not_a_syn3 = 1;
+	  u64 hash0, hash1, hash2, hash3;
+
+	  /* Prefetch next iteration. */
+	  {
+	    vlib_buffer_t *p4, *p5, *p6, *p7;
+
+	    p4 = vlib_get_buffer (vm, from[4]);
+	    p5 = vlib_get_buffer (vm, from[5]);
+	    p6 = vlib_get_buffer (vm, from[6]);
+	    p7 = vlib_get_buffer (vm, from[7]);
+
+	    vlib_prefetch_buffer_header (p4, LOAD);
+	    vlib_prefetch_buffer_header (p5, LOAD);
+	    vlib_prefetch_buffer_header (p6, LOAD);
+	    vlib_prefetch_buffer_header (p7, LOAD);
+
+	    CLIB_PREFETCH (p4->data, CLIB_CACHE_LINE_BYTES, STORE);
+	    CLIB_PREFETCH (p5->data, CLIB_CACHE_LINE_BYTES, STORE);
+	    CLIB_PREFETCH (p6->data, CLIB_CACHE_LINE_BYTES, STORE);
+	    CLIB_PREFETCH (p7->data, CLIB_CACHE_LINE_BYTES, STORE);
+	  }
+
+	  /* speculatively enqueue b0 and b1 to the current next frame */
+	  to_next[0] = bi0 = from[0];
+	  to_next[1] = bi1 = from[1];
+	  to_next[2] = bi2 = from[2];
+	  to_next[3] = bi3 = from[3];
+	  from += 4;
+	  to_next += 4;
+	  n_left_from -= 4;
+	  n_left_to_next -= 4;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  b1 = vlib_get_buffer (vm, bi1);
+	  b2 = vlib_get_buffer (vm, bi2);
+	  b3 = vlib_get_buffer (vm, bi3);
+
+	  vnet_get_config_data
+	    (&cm->config_main, &b0->current_config_index,
+	     &next0, 0 /* sizeof (c0[0]) */ );
+	  vnet_get_config_data
+	    (&cm->config_main, &b1->current_config_index,
+	     &next1, 0 /* sizeof (c0[0]) */ );
+	  vnet_get_config_data
+	    (&cm->config_main, &b2->current_config_index,
+	     &next2, 0 /* sizeof (c0[0]) */ );
+	  vnet_get_config_data
+	    (&cm->config_main, &b3->current_config_index,
+	     &next3, 0 /* sizeof (c0[0]) */ );
+
+	  /* Not TCP? */
+	  ip0 = vlib_buffer_get_current (b0);
+	  if (ip0->protocol != IP_PROTOCOL_TCP)
+	    goto trace00;
+
+	  tcp0 = ip4_next_header (ip0);
+	  /*
+	   * Not a SYN?
+	   * $$$$ hack: the TCP bitfield flags seem not to compile
+	   * correct code.
+	   */
+	  if (PREDICT_TRUE (!(tcp0->flags & 0x2)))
+	    goto trace00;
+
+	  not_a_syn0 = 0;
+	  hash0 = clib_xxhash ((u64) ip0->src_address.as_u32);
+	  c0 = &rt->syn_counts[hash0 & (_vec_len (rt->syn_counts) - 1)];
+	  if (PREDICT_FALSE (*c0 >= 0x80))
+	    {
+	      next0 = SYN_FILTER_NEXT_DROP;
+	      b0->error = node->errors[SYN_FILTER_ERROR_THROTTLED];
+	      goto trace00;
+	    }
+	  *c0 += 1;
+	  ok_syn_packets++;
+
+	trace00:
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      syn_filter4_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->not_a_syn = not_a_syn0;
+	      t->next_index = next0;
+	      t->filter_value = not_a_syn0 ? 0 : *c0;
+	    }
+
+	  /* Not TCP? */
+	  ip1 = vlib_buffer_get_current (b1);
+	  if (ip1->protocol != IP_PROTOCOL_TCP)
+	    goto trace01;
+
+	  tcp1 = ip4_next_header (ip1);
+	  /*
+	   * Not a SYN?
+	   * $$$$ hack: the TCP bitfield flags seem not to compile
+	   * correct code.
+	   */
+	  if (PREDICT_TRUE (!(tcp1->flags & 0x2)))
+	    goto trace01;
+
+	  not_a_syn1 = 0;
+	  hash1 = clib_xxhash ((u64) ip1->src_address.as_u32);
+	  c1 = &rt->syn_counts[hash1 & (_vec_len (rt->syn_counts) - 1)];
+	  if (PREDICT_FALSE (*c1 >= 0x80))
+	    {
+	      next1 = SYN_FILTER_NEXT_DROP;
+	      b1->error = node->errors[SYN_FILTER_ERROR_THROTTLED];
+	      goto trace01;
+	    }
+	  *c1 += 1;
+	  ok_syn_packets++;
+
+	trace01:
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b1->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      syn_filter4_trace_t *t =
+		vlib_add_trace (vm, node, b1, sizeof (*t));
+	      t->not_a_syn = not_a_syn1;
+	      t->next_index = next1;
+	      t->filter_value = not_a_syn1 ? 0 : *c1;
+	    }
+
+	  /* Not TCP? */
+	  ip2 = vlib_buffer_get_current (b2);
+	  if (ip2->protocol != IP_PROTOCOL_TCP)
+	    goto trace02;
+
+	  tcp2 = ip4_next_header (ip2);
+	  /*
+	   * Not a SYN?
+	   * $$$$ hack: the TCP bitfield flags seem not to compile
+	   * correct code.
+	   */
+	  if (PREDICT_TRUE (!(tcp2->flags & 0x2)))
+	    goto trace02;
+
+	  not_a_syn2 = 0;
+	  hash2 = clib_xxhash ((u64) ip2->src_address.as_u32);
+	  c2 = &rt->syn_counts[hash2 & (_vec_len (rt->syn_counts) - 1)];
+	  if (PREDICT_FALSE (*c2 >= 0x80))
+	    {
+	      next2 = SYN_FILTER_NEXT_DROP;
+	      b2->error = node->errors[SYN_FILTER_ERROR_THROTTLED];
+	      goto trace02;
+	    }
+	  *c2 += 1;
+	  ok_syn_packets++;
+
+	trace02:
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b2->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      syn_filter4_trace_t *t =
+		vlib_add_trace (vm, node, b2, sizeof (*t));
+	      t->not_a_syn = not_a_syn2;
+	      t->next_index = next2;
+	      t->filter_value = not_a_syn2 ? 0 : *c2;
+	    }
+
+	  /* Not TCP? */
+	  ip3 = vlib_buffer_get_current (b3);
+	  if (ip3->protocol != IP_PROTOCOL_TCP)
+	    goto trace03;
+
+	  tcp3 = ip4_next_header (ip3);
+	  /*
+	   * Not a SYN?
+	   * $$$$ hack: the TCP bitfield flags seem not to compile
+	   * correct code.
+	   */
+	  if (PREDICT_TRUE (!(tcp3->flags & 0x2)))
+	    goto trace03;
+
+	  not_a_syn3 = 0;
+	  hash3 = clib_xxhash ((u64) ip3->src_address.as_u32);
+	  c3 = &rt->syn_counts[hash3 & (_vec_len (rt->syn_counts) - 1)];
+	  if (PREDICT_FALSE (*c3 >= 0x80))
+	    {
+	      next3 = SYN_FILTER_NEXT_DROP;
+	      b3->error = node->errors[SYN_FILTER_ERROR_THROTTLED];
+	      goto trace03;
+	    }
+	  *c3 += 1;
+	  ok_syn_packets++;
+
+	trace03:
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b3->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      syn_filter4_trace_t *t =
+		vlib_add_trace (vm, node, b3, sizeof (*t));
+	      t->not_a_syn = not_a_syn3;
+	      t->next_index = next3;
+	      t->filter_value = not_a_syn3 ? 0 : *c3;
+	    }
+	  vlib_validate_buffer_enqueue_x4 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   bi0, bi1, bi2, bi3,
+					   next0, next1, next2, next3);
+	}
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  u32 next0;
+	  ip4_header_t *ip0;
+	  tcp_header_t *tcp0;
+	  u32 not_a_syn0 = 1;
+	  u32 hash0;
+	  u8 *c0;
+
+	  /* speculatively enqueue b0 to the current next frame */
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+
+	  vnet_get_config_data
+	    (&cm->config_main, &b0->current_config_index,
+	     &next0, 0 /* sizeof (c0[0]) */ );
+
+	  /* Not TCP? */
+	  ip0 = vlib_buffer_get_current (b0);
+	  if (ip0->protocol != IP_PROTOCOL_TCP)
+	    goto trace0;
+
+	  tcp0 = ip4_next_header (ip0);
+	  /*
+	   * Not a SYN?
+	   * $$$$ hack: the TCP bitfield flags seem not to compile
+	   * correct code.
+	   */
+	  if (PREDICT_TRUE (!(tcp0->flags & 0x2)))
+	    goto trace0;
+
+	  not_a_syn0 = 0;
+	  hash0 = clib_xxhash ((u64) ip0->src_address.as_u32);
+	  c0 = &rt->syn_counts[hash0 & (_vec_len (rt->syn_counts) - 1)];
+	  if (PREDICT_FALSE (*c0 >= 0x80))
+	    {
+	      next0 = SYN_FILTER_NEXT_DROP;
+	      b0->error = node->errors[SYN_FILTER_ERROR_THROTTLED];
+	      goto trace0;
+	    }
+	  *c0 += 1;
+	  ok_syn_packets++;
+
+	trace0:
+
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      syn_filter4_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->not_a_syn = not_a_syn0;
+	      t->next_index = next0;
+	      t->filter_value = not_a_syn0 ? 0 : *c0;
+	    }
+
+	  /* 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);
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  vlib_node_increment_counter (vm, syn_filter4_node.index,
+			       SYN_FILTER_ERROR_OK, ok_syn_packets);
+  return frame->n_vectors;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (syn_filter4_node, static) =
+{
+  .function = syn_filter4_node_fn,
+  .name = "syn-filter-4",
+  .vector_size = sizeof (u32),
+  .format_trace = format_syn_filter4_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+
+  .runtime_data_bytes = sizeof (syn_filter4_runtime_t),
+  .n_errors = ARRAY_LEN(syn_filter4_error_strings),
+  .error_strings = syn_filter4_error_strings,
+
+  .n_next_nodes = SYN_FILTER_N_NEXT,
+
+  /* edit / add dispositions here */
+  .next_nodes = {
+    [SYN_FILTER_NEXT_DROP] = "error-drop",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (syn_filter4_node, syn_filter4_node_fn);
+
+/* *INDENT-OFF* */
+VNET_FEATURE_INIT (syn_filter_4, static) =
+{
+  .arc_name = "ip4-local",
+  .node_name = "syn-filter-4",
+  .runs_before = VNET_FEATURES("ip4-local-end-of-arc"),
+};
+/* *INDENT-ON* */
+
+int
+syn_filter_enable_disable (u32 sw_if_index, int enable_disable)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  vnet_sw_interface_t *sw;
+  int rv = 0;
+
+  /* Utterly wrong? */
+  if (pool_is_free_index (vnm->interface_main.sw_interfaces, sw_if_index))
+    return VNET_API_ERROR_INVALID_SW_IF_INDEX;
+
+  /* Not a physical port? */
+  sw = vnet_get_sw_interface (vnm, sw_if_index);
+  if (sw->type != VNET_SW_INTERFACE_TYPE_HARDWARE)
+    return VNET_API_ERROR_INVALID_SW_IF_INDEX;
+
+  if (enable_disable)
+    {
+      vlib_main_t *vm = vlib_get_main ();
+      syn_filter4_runtime_t *rt;
+
+      rt = vlib_node_get_runtime_data (vm, syn_filter4_node.index);
+      vec_validate (rt->syn_counts, 1023);
+      /*
+       * Given perfect disperson / optimal hashing results:
+       * Allow 128k (successful) syns/sec. 1024, buckets each of which
+       * absorb 128 syns before filtering. Reset table once a second.
+       * Reality bites, lets try resetting once every 100ms.
+       */
+      rt->reset_interval = 0.1;	/* reset interval in seconds */
+    }
+
+  rv = vnet_feature_enable_disable ("ip4-local", "syn-filter-4",
+				    sw_if_index, enable_disable, 0, 0);
+
+  return rv;
+}
+
+static clib_error_t *
+syn_filter_enable_disable_command_fn (vlib_main_t * vm,
+				      unformat_input_t * input,
+				      vlib_cli_command_t * cmd)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  u32 sw_if_index = ~0;
+  int enable_disable = 1;
+  int rv;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "disable"))
+	enable_disable = 0;
+      else if (unformat (input, "%U", unformat_vnet_sw_interface,
+			 vnm, &sw_if_index))
+	;
+      else
+	break;
+    }
+
+  if (sw_if_index == ~0)
+    return clib_error_return (0, "Please specify an interface...");
+
+  rv = syn_filter_enable_disable (sw_if_index, enable_disable);
+
+  switch (rv)
+    {
+    case 0:
+      break;
+
+    case VNET_API_ERROR_INVALID_SW_IF_INDEX:
+      return clib_error_return
+	(0, "Invalid interface, only works on physical ports");
+      break;
+
+    case VNET_API_ERROR_UNIMPLEMENTED:
+      return clib_error_return (0,
+				"Device driver doesn't support redirection");
+      break;
+
+    case VNET_API_ERROR_INVALID_VALUE:
+      return clib_error_return (0, "feature arc not found");
+
+    case VNET_API_ERROR_INVALID_VALUE_2:
+      return clib_error_return (0, "feature node not found");
+
+    default:
+      return clib_error_return (0, "syn_filter_enable_disable returned %d",
+				rv);
+    }
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (sr_content_command, static) =
+{
+  .path = "ip syn filter",
+  .short_help = "ip syn filter <interface-name> [disable]",
+  .function = syn_filter_enable_disable_command_fn,
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */