snort: snort3 plugin and DAQ

Zero copy interface which exposes VPP buffers to snort instance(s).
Includes VPP DAQ which is compiled only if libdaq 3 API headers are
available.

Type: feature
Change-Id: I96611b43f94fbae091e7391589e0454ae66de88b
Signed-off-by: Damjan Marion <damarion@cisco.com>
Signed-off-by: Filip Tehlar <ftehlar@cisco.com>

1 files changed, 223 insertions, 0 deletions

diff --git a/src/plugins/snort/enqueue.c b/src/plugins/snort/enqueue.c
new file mode 100644
index 00000000000..3f44e8013fd
--- /dev/null
+++ b/src/plugins/snort/enqueue.c
@@ -0,0 +1,223 @@
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright(c) 2021 Cisco Systems, Inc.
+ */
+
+#include <vlib/vlib.h>
+#include <vnet/feature/feature.h>
+#include <snort/snort.h>
+
+typedef struct
+{
+  u32 next_index;
+  u32 sw_if_index;
+  u16 instance;
+  u16 qpair;
+  u32 enq_slot;
+  u32 desc_index;
+  daq_vpp_desc_t desc;
+} snort_enq_trace_t;
+
+static u8 *
+format_snort_enq_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 *);
+  snort_enq_trace_t *t = va_arg (*args, snort_enq_trace_t *);
+  u32 indent = format_get_indent (s);
+
+  s = format (s,
+	      "sw-if-index %u next-index %u\n"
+	      "%Uinstance %u qpair %u desc-index %u slot %u\n"
+	      "%Udesc: buffer-pool %u offset %u len %u address-space-id %u\n",
+	      t->sw_if_index, t->next_index, format_white_space, indent,
+	      t->instance, t->qpair, t->desc_index, t->enq_slot,
+	      format_white_space, indent, t->desc.buffer_pool, t->desc.offset,
+	      t->desc.length, t->desc.address_space_id);
+
+  return s;
+}
+
+#define foreach_snort_enq_error                                               \
+  _ (SOCKET_ERROR, "write socket error")                                      \
+  _ (NO_INSTANCE, "no snort instance")                                        \
+  _ (NO_ENQ_SLOTS, "no enqueue slots (packet dropped)")
+
+typedef enum
+{
+#define _(sym, str) SNORT_ENQ_ERROR_##sym,
+  foreach_snort_enq_error
+#undef _
+    SNORT_ENQ_N_ERROR,
+} snort_enq_error_t;
+
+static char *snort_enq_error_strings[] = {
+#define _(sym, string) string,
+  foreach_snort_enq_error
+#undef _
+};
+
+static_always_inline uword
+snort_enq_node_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
+		       vlib_frame_t *frame, int with_trace)
+{
+  snort_main_t *sm = &snort_main;
+  snort_instance_t *si = 0;
+  snort_qpair_t *qp = 0;
+  u32 thread_index = vm->thread_index;
+  u32 n_left = frame->n_vectors;
+  u32 n_trace = 0;
+  u32 total_enq = 0, n_processed = 0;
+  u32 *from = vlib_frame_vector_args (frame);
+  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
+  u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
+
+  vlib_get_buffers (vm, from, bufs, n_left);
+
+  while (n_left)
+    {
+      u32 instance_index, next_index, n;
+      instance_index =
+	*(u32 *) vnet_feature_next_with_data (&next_index, b[0], sizeof (u32));
+      si = vec_elt_at_index (sm->instances, instance_index);
+
+      /* if client isn't connected skip enqueue and take default action */
+      if (PREDICT_FALSE (si->client_index == ~0))
+	{
+	  if (si->drop_on_disconnect)
+	    next[0] = SNORT_ENQ_NEXT_DROP;
+	  else
+	    next[0] = next_index;
+	  next++;
+	  n_processed++;
+	}
+      else
+	{
+	  qp = vec_elt_at_index (si->qpairs, thread_index);
+	  n = qp->n_pending++;
+	  daq_vpp_desc_t *d = qp->pending_descs + n;
+
+	  qp->pending_nexts[n] = next_index;
+	  qp->pending_buffers[n] = from[0];
+
+	  vlib_buffer_chain_linearize (vm, b[0]);
+
+	  /* If this pkt is traced, snapshoot the data */
+	  if (with_trace && b[0]->flags & VLIB_BUFFER_IS_TRACED)
+	    n_trace++;
+
+	  /* fill descriptor */
+	  d->buffer_pool = b[0]->buffer_pool_index;
+	  d->length = b[0]->current_length;
+	  d->offset = (u8 *) b[0]->data + b[0]->current_data -
+		      sm->buffer_pool_base_addrs[d->buffer_pool];
+	  d->address_space_id = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
+	}
+
+      n_left--;
+      from++;
+      b++;
+    }
+
+  if (n_processed)
+    {
+      vlib_node_increment_counter (vm, snort_enq_node.index,
+				   SNORT_ENQ_ERROR_NO_INSTANCE, n_processed);
+      vlib_buffer_enqueue_to_next (vm, node, vlib_frame_vector_args (frame),
+				   nexts, n_processed);
+    }
+
+  vec_foreach (si, sm->instances)
+    {
+      u32 head, freelist_len, n_pending, n_enq, mask;
+      u64 ctr = 1;
+      qp = vec_elt_at_index (si->qpairs, thread_index);
+      mask = pow2_mask (qp->log2_queue_size);
+      n_pending = qp->n_pending;
+      qp->n_pending = 0;
+
+      if (n_pending == 0)
+	continue;
+
+      freelist_len = vec_len (qp->freelist);
+
+      if (freelist_len < n_pending)
+	{
+	  n_enq = freelist_len;
+	  vlib_buffer_free (vm, qp->pending_buffers + n_enq,
+			    n_pending - n_enq);
+	  vlib_node_increment_counter (vm, snort_enq_node.index,
+				       SNORT_ENQ_ERROR_NO_ENQ_SLOTS,
+				       n_pending - n_enq);
+	}
+      else
+	n_enq = n_pending;
+
+      if (n_enq == 0)
+	continue;
+
+      total_enq += n_enq;
+      head = *qp->enq_head;
+
+      for (u32 i = 0; i < n_enq; i++)
+	{
+	  u32 desc_index = qp->freelist[--freelist_len];
+	  qp->next_indices[desc_index] = qp->pending_nexts[i];
+	  ASSERT (qp->buffer_indices[desc_index] == ~0);
+	  qp->buffer_indices[desc_index] = qp->pending_buffers[i];
+	  clib_memcpy_fast (qp->descriptors + desc_index,
+			    qp->pending_descs + i, sizeof (daq_vpp_desc_t));
+	  qp->enq_ring[head & mask] = desc_index;
+
+	  /* trace */
+	  if (with_trace && n_trace)
+	    {
+	      vlib_buffer_t *tb = vlib_get_buffer (vm, qp->pending_buffers[i]);
+	      if (tb->flags & VLIB_BUFFER_IS_TRACED)
+		{
+		  snort_enq_trace_t *t =
+		    vlib_add_trace (vm, node, tb, sizeof (*t));
+		  t->sw_if_index = vnet_buffer (tb)->sw_if_index[VLIB_RX];
+		  t->next_index = qp->pending_nexts[i];
+		  t->instance = si->index;
+		  t->qpair = qp - si->qpairs;
+		  t->enq_slot = head & mask;
+		  t->desc_index = desc_index;
+		  clib_memcpy_fast (&t->desc, qp->pending_descs + i,
+				    sizeof (daq_vpp_desc_t));
+		}
+	    }
+	  head = head + 1;
+	}
+
+      __atomic_store_n (qp->enq_head, head, __ATOMIC_RELEASE);
+      _vec_len (qp->freelist) = freelist_len;
+      if (sm->input_mode == VLIB_NODE_STATE_INTERRUPT)
+	{
+	  if (write (qp->enq_fd, &ctr, sizeof (ctr)) < 0)
+	    vlib_node_increment_counter (vm, snort_enq_node.index,
+					 SNORT_ENQ_ERROR_SOCKET_ERROR, 1);
+	}
+    }
+
+  return total_enq;
+}
+
+VLIB_NODE_FN (snort_enq_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
+{
+  if (PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE))
+    return snort_enq_node_inline (vm, node, frame, 1 /* is_trace*/);
+  else
+    return snort_enq_node_inline (vm, node, frame, 0 /* is_trace*/);
+}
+
+VLIB_REGISTER_NODE (snort_enq_node) = {
+  .name = "snort-enq",
+  .vector_size = sizeof (u32),
+  .format_trace = format_snort_enq_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_next_nodes = SNORT_ENQ_N_NEXT_NODES,
+  .next_nodes = SNORT_ENQ_NEXT_NODES,
+  .n_errors = ARRAY_LEN (snort_enq_error_strings),
+  .error_strings = snort_enq_error_strings,
+};