pg: set vnet buffer flags in pg streams

See .../extras/pg/checksum_offload.pg for a nontrivial example, which
deliberately sets bogus ip and udp checksums in the generated packets,
then fixes the mess with (software emulated) hardware checksum
offload.

Validated via "pcap dispatch trace on max 1000 buffer-trace pg-input 100".
Packets stuffed into loop1-output have the configured bogus ip and udp
checksums. vnet_calc_checksums_inline(...) fixes the checksums, which
are correct when packets visit loop1-tx.

The packet generator is a dumb robot in this regard. If you ask for a
ridiculous flag combination - example: ip4 and ip6 - your mileage may
vary.

Type: feature

Signed-off-by: Dave Barach <dave@barachs.net>
Change-Id: I6d9e790f373bcd9e445a89113ca8e4c8f9aa9419

5 files changed, 40 insertions, 1 deletions

diff --git a/src/vnet/interface_format.c b/src/vnet/interface_format.c
index 507e2676ccb..8278102c644 100644
--- a/src/vnet/interface_format.c
+++ b/src/vnet/interface_format.c
@@ -671,6 +671,34 @@ vnet_register_format_buffer_opaque2_helper (vnet_buffer_opquae_formatter_t fp)
 
 
 uword
+unformat_vnet_buffer_flags (unformat_input_t * input, va_list * args)
+{
+  u32 *flagp = va_arg (*args, u32 *);
+  int rv = 0;
+  u32 flags = 0;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      /* Red herring, there is no such buffer flag */
+      if (unformat (input, "avail8"))
+	return 0;
+#define _(bit,enum,str,verbose)                                 \
+      else if (unformat (input, str))                           \
+        {                                                       \
+          flags |= (1 << LOG2_VLIB_BUFFER_FLAG_USER(bit));      \
+          rv = 1;                                               \
+        }
+      foreach_vnet_buffer_flag
+#undef _
+	else
+	break;
+    }
+  if (rv)
+    *flagp = flags;
+  return rv;
+}
+
+uword
 unformat_vnet_hw_interface (unformat_input_t * input, va_list * args)
 {
   vnet_main_t *vnm = va_arg (*args, vnet_main_t *);
diff --git a/src/vnet/interface_funcs.h b/src/vnet/interface_funcs.h
index f5c66d447de..7d9c098b118 100644
--- a/src/vnet/interface_funcs.h
+++ b/src/vnet/interface_funcs.h
@@ -444,6 +444,7 @@ format_function_t format_vnet_sw_interface_flags;
 /* Parses sw/hw interface name -> index. */
 unformat_function_t unformat_vnet_sw_interface;
 unformat_function_t unformat_vnet_hw_interface;
+unformat_function_t unformat_vnet_buffer_flags;
 
 /* Parses interface flags (up, down, enable, disable, etc.) */
 unformat_function_t unformat_vnet_hw_interface_flags;
diff --git a/src/vnet/pg/cli.c b/src/vnet/pg/cli.c
index 9336ca406d7..b3aaddfda2b 100644
--- a/src/vnet/pg/cli.c
+++ b/src/vnet/pg/cli.c
@@ -376,6 +376,10 @@ new_stream (vlib_main_t * vm,
       else if (unformat (input, "source pg%u", &s.if_id))
 	;
 
+      else if (unformat (input, "buffer-flags %U",
+			 unformat_vnet_buffer_flags, &s.buffer_flags))
+	;
+
       else if (unformat (input, "node %U",
 			 unformat_vlib_node, vm, &s.node_index))
 	;
diff --git a/src/vnet/pg/input.c b/src/vnet/pg/input.c
index bbcd34e763a..8ba3b361894 100644
--- a/src/vnet/pg/input.c
+++ b/src/vnet/pg/input.c
@@ -1106,6 +1106,8 @@ init_buffers_inline (vlib_main_t * vm,
 
       b0 = vlib_get_buffer (vm, bi0);
       b1 = vlib_get_buffer (vm, bi1);
+      b0->flags |= s->buffer_flags;
+      b1->flags |= s->buffer_flags;
 
       vnet_buffer (b0)->sw_if_index[VLIB_RX] =
 	vnet_buffer (b1)->sw_if_index[VLIB_RX] = s->sw_if_index[VLIB_RX];
@@ -1135,6 +1137,7 @@ init_buffers_inline (vlib_main_t * vm,
       n_left -= 1;
 
       b0 = vlib_get_buffer (vm, bi0);
+      b0->flags |= s->buffer_flags;
       vnet_buffer (b0)->sw_if_index[VLIB_RX] = s->sw_if_index[VLIB_RX];
       vnet_buffer (b0)->sw_if_index[VLIB_TX] = s->sw_if_index[VLIB_TX];
 
@@ -1269,7 +1272,7 @@ pg_stream_fill_replay (pg_main_t * pg, pg_stream_t * s, u32 n_alloc)
 	  clib_memcpy_fast (b->data, d0 + data_offset, bytes_this_chunk);
 	  vnet_buffer (b)->sw_if_index[VLIB_RX] = s->sw_if_index[VLIB_RX];
 	  vnet_buffer (b)->sw_if_index[VLIB_TX] = s->sw_if_index[VLIB_TX];
-	  b->flags = 0;
+	  b->flags = s->buffer_flags;
 	  b->next_buffer = 0;
 	  b->current_data = 0;
 	  b->current_length = bytes_this_chunk;
diff --git a/src/vnet/pg/pg.h b/src/vnet/pg/pg.h
index 55bc75dc282..a6616d9ced7 100644
--- a/src/vnet/pg/pg.h
+++ b/src/vnet/pg/pg.h
@@ -123,6 +123,9 @@ typedef struct pg_stream_t
      for max_packet_bytes. */
   u32 buffer_bytes;
 
+  /* Buffer flags to set in each packet e.g. checksum offload flags */
+  u32 buffer_flags;
+
   /* Last packet length if packet size edit type is increment. */
   u32 last_increment_packet_size;