ip: fix udp/tcp checksum corner cases

When checksumming chained buffers with odd lengths: insert a
NULL byte, or the calculation fails.

Type: fix

Signed-off-by: Dave Barach <dave@barachs.net>
Signed-off-by: John Lo <loj@cisco.com>
Change-Id: I380f7c42897bdb28c8c29aa1c4cdaaa849cc9ecc

1 files changed, 215 insertions, 0 deletions

diff --git a/src/plugins/oddbuf/node.c b/src/plugins/oddbuf/node.c
new file mode 100644
index 00000000000..d495abaf950
--- /dev/null
+++ b/src/plugins/oddbuf/node.c
@@ -0,0 +1,215 @@
+/*
+ * node.c - skeleton vpp engine plug-in dual-loop node skeleton
+ *
+ * Copyright (c) <current-year> <your-organization>
+ * 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 <oddbuf/oddbuf.h>
+
+typedef struct
+{
+  u32 sw_if_index;
+  u32 next_index;
+  u16 udp_checksum;
+} oddbuf_trace_t;
+
+#ifndef CLIB_MARCH_VARIANT
+
+/* packet trace format function */
+static u8 *
+format_oddbuf_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 *);
+  oddbuf_trace_t *t = va_arg (*args, oddbuf_trace_t *);
+
+  s = format (s, "ODDBUF: sw_if_index %d, next index %d, udp checksum %04x\n",
+	      t->sw_if_index, t->next_index, (u32) t->udp_checksum);
+  return s;
+}
+
+vlib_node_registration_t oddbuf_node;
+
+#endif /* CLIB_MARCH_VARIANT */
+
+#define foreach_oddbuf_error \
+_(SWAPPED, "Mac swap packets processed")
+
+typedef enum
+{
+#define _(sym,str) ODDBUF_ERROR_##sym,
+  foreach_oddbuf_error
+#undef _
+    ODDBUF_N_ERROR,
+} oddbuf_error_t;
+
+#ifndef CLIB_MARCH_VARIANT
+static char *oddbuf_error_strings[] = {
+#define _(sym,string) string,
+  foreach_oddbuf_error
+#undef _
+};
+#endif /* CLIB_MARCH_VARIANT */
+
+typedef enum
+{
+  ODDBUF_NEXT_DROP,
+  ODDBUF_N_NEXT,
+} oddbuf_next_t;
+
+
+always_inline uword
+oddbuf_inline (vlib_main_t * vm,
+	       vlib_node_runtime_t * node, vlib_frame_t * frame,
+	       int is_ip4, int is_trace)
+{
+  oddbuf_main_t *om = &oddbuf_main;
+  u32 n_left_from, *from;
+  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
+  vlib_buffer_t *b0, *b0next;
+  u32 bi;
+  u16 nexts[VLIB_FRAME_SIZE], *next;
+  u16 save_current_length;
+  u32 next0;
+  u8 *src, *dst;
+  int i;
+  ethernet_header_t *eh;
+  ip4_header_t *ip;
+  udp_header_t *udp;
+
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+
+  vlib_get_buffers (vm, from, bufs, n_left_from);
+  b = bufs;
+  next = nexts;
+
+  while (n_left_from > 0)
+    {
+      b0 = b[0];
+      vnet_feature_next (&next0, b0);
+      nexts[0] = next0;
+
+      if (vlib_buffer_alloc (vm, &bi, 1) != 1)
+	{
+	  clib_warning ("Buffer alloc fail, skipping");
+	  goto skip;
+	}
+
+      if (om->first_chunk_offset)
+	{
+	  memmove (b0->data + b0->current_data + om->first_chunk_offset,
+		   b0->data + b0->current_data, b0->current_length);
+	  b0->current_data += om->first_chunk_offset;
+	}
+
+      eh = vlib_buffer_get_current (b0);
+      ip = (ip4_header_t *) (eh + 1);
+      udp = (udp_header_t *) (ip4_next_header (ip));
+
+      if (1)
+	{
+	  save_current_length = vlib_buffer_length_in_chain (vm, b0);
+
+	  b0next = vlib_get_buffer (vm, bi);
+	  b0->flags |= VLIB_BUFFER_NEXT_PRESENT;
+	  b0->flags &= ~VLIB_BUFFER_TOTAL_LENGTH_VALID;
+	  b0->next_buffer = bi;
+
+	  src = b0->data + b0->current_data + b0->current_length -
+	    om->n_to_copy;
+	  b0next->current_data = om->second_chunk_offset;
+	  b0next->current_length = om->n_to_copy;
+	  dst = b0next->data + b0next->current_data;
+
+	  for (i = 0; i < om->n_to_copy; i++)
+	    dst[i] = src[i];
+
+	  b0->current_length -= om->n_to_copy;
+	  b0next->current_length = om->n_to_copy;
+
+	  if (vlib_buffer_length_in_chain (vm, b0) != save_current_length)
+	    clib_warning ("OOPS, length incorrect after chunk split...");
+	}
+
+      udp->checksum = 0;
+      udp->checksum = ip4_tcp_udp_compute_checksum (vm, b0, ip);
+
+      if (is_trace)
+	{
+	  if (b[0]->flags & VLIB_BUFFER_IS_TRACED)
+	    {
+	      oddbuf_trace_t *t =
+		vlib_add_trace (vm, node, b[0], sizeof (*t));
+	      t->next_index = next[0];
+	      t->sw_if_index = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
+	      t->udp_checksum = clib_net_to_host_u16 (udp->checksum);
+	    }
+	}
+
+    skip:
+      b += 1;
+      next += 1;
+      n_left_from -= 1;
+    }
+
+  vlib_buffer_enqueue_to_next (vm, node, from, nexts, frame->n_vectors);
+
+  return frame->n_vectors;
+}
+
+VLIB_NODE_FN (oddbuf_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
+			    vlib_frame_t * frame)
+{
+  if (PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE))
+    return oddbuf_inline (vm, node, frame, 1 /* is_ip4 */ ,
+			  1 /* is_trace */ );
+  else
+    return oddbuf_inline (vm, node, frame, 1 /* is_ip4 */ ,
+			  0 /* is_trace */ );
+}
+
+/* *INDENT-OFF* */
+#ifndef CLIB_MARCH_VARIANT
+VLIB_REGISTER_NODE (oddbuf_node) =
+{
+  .name = "oddbuf",
+  .vector_size = sizeof (u32),
+  .format_trace = format_oddbuf_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+
+  .n_errors = ARRAY_LEN(oddbuf_error_strings),
+  .error_strings = oddbuf_error_strings,
+
+  .n_next_nodes = ODDBUF_N_NEXT,
+
+  /* edit / add dispositions here */
+  .next_nodes = {
+        [ODDBUF_NEXT_DROP] = "error-drop",
+  },
+};
+#endif /* CLIB_MARCH_VARIANT */
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */