[vpp] Add sonic_ext RIF loopback packet action nodes and binary API

rules/vpp.mk

@@ -2,12 +2,13 @@
 
 VPP_VERSION_BASE = 2606
 # Bump the minor suffix whenever vppbld/patches/series or any patch file
-# under vppbld/patches/*.patch changes content. The VPP_VERSION_SONIC string
+# under vppbld/patches/*.patch -- or any plugin under vppbld/plugins/* -- changes
+# content. The VPP_VERSION_SONIC string
 # is the cache key used by vppbld/Makefile to fetch pre-built debs from
 # https://packages.buildkite.com/sonic-vpp/vpp; if the suffix isn't bumped,
 # downstream sonic-buildimage builds will silently pull stale debs that
 # pre-date the new patch series and end up with VPP/SAI CRC drift.
-VPP_VERSION = $(VPP_VERSION_BASE)-0.3
+VPP_VERSION = $(VPP_VERSION_BASE)-0.8
 VPP_VERSION_SONIC = $(VPP_VERSION)+b1sonic1
 VPP_SRC_PATH = platform/vpp/vppbld
 

vppbld/plugins/sonic_ext/CMakeLists.txt

@@ -18,8 +18,13 @@ add_vpp_plugin(sonic_ext
   aggr_tap_redirect_node.c
   host_xc_node.c
   l2_trap_fixup_node.c
+  ip4_loopback_node.c
+  ip6_loopback_node.c
   cli.c
 
+  API_FILES
+  sonic_ext.api
+
   LINK_LIBRARIES
   lcp
 )

vppbld/plugins/sonic_ext/FEATURE.yaml

@@ -3,6 +3,8 @@ maintainer: SONiC-VPP contributors
 features:
   - punt-via-member: redirect BVI-RX punted unicast/ARP to the original member tap
   - host-xc: bypass ethernet-input for packets injected from the linux-cp host tap
+  - iface-loopback: drop and count routed hairpin packets (RIF loopback packet
+    action) whose egress interface equals their ingress interface
 description: "SONiC VPP extensions for BVI/L2 punt and host-side cross-connect"
 state: experimental
 properties: [API, CLI]

vppbld/plugins/sonic_ext/ip4_loopback_node.c

@@ -0,0 +1,145 @@
+/*
+ * Copyright (c) 2026 SONiC-VPP contributors
+ * 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/feature/feature.h>
+#include <vnet/ip/ip4_packet.h>
+#include <sonic_ext/sonic_ext.h>
+
+typedef struct
+{
+  u32 rx_sw_if_index;
+  u32 tx_sw_if_index;
+  u32 next_index;
+  u8 dropped;
+} ip4_loopback_trace_t;
+
+static u8 *
+format_ip4_loopback_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 *);
+  ip4_loopback_trace_t *t = va_arg (*args, ip4_loopback_trace_t *);
+
+  s = format (s, "SONIC-EXT-IP4-LOOPBACK: rx %d tx %d next %d %s",
+	      t->rx_sw_if_index, t->tx_sw_if_index, t->next_index,
+	      t->dropped ? "(hairpin-drop)" : "");
+  return s;
+}
+
+#define foreach_ip4_loopback_error _ (HAIRPIN_DROP, "hairpin packets dropped")
+
+typedef enum
+{
+#define _(sym, str) IP4_LOOPBACK_ERROR_##sym,
+  foreach_ip4_loopback_error
+#undef _
+    IP4_LOOPBACK_N_ERROR,
+} ip4_loopback_error_t;
+
+static char *ip4_loopback_error_strings[] = {
+#define _(sym, string) string,
+  foreach_ip4_loopback_error
+#undef _
+};
+
+typedef enum
+{
+  IP4_LOOPBACK_NEXT_DROP,
+  IP4_LOOPBACK_NEXT_INTERFACE_OUTPUT,
+  IP4_LOOPBACK_N_NEXT,
+} ip4_loopback_next_t;
+
+VLIB_NODE_FN (sonic_ext_ip4_loopback_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
+{
+  sonic_ext_main_t *sem = &sonic_ext_main;
+  vnet_main_t *vnm = vnet_get_main ();
+  u32 thread_index = vm->thread_index;
+  u32 n_left_from, *from;
+  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
+  u16 nexts[VLIB_FRAME_SIZE], *next;
+
+  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)
+    {
+      u32 rx = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
+      u32 tx = vnet_buffer (b[0])->sw_if_index[VLIB_TX];
+      u8 action = (tx < vec_len (sem->loopback_action_by_sw_if_index))
+		    ? sem->loopback_action_by_sw_if_index[tx]
+		    : SONIC_EXT_LOOPBACK_ACTION_FORWARD;
+      u8 dropped = 0;
+
+      if (PREDICT_FALSE (rx == tx && action == SONIC_EXT_LOOPBACK_ACTION_DROP))
+	{
+	  next[0] = IP4_LOOPBACK_NEXT_DROP;
+	  b[0]->error = node->errors[IP4_LOOPBACK_ERROR_HAIRPIN_DROP];
+	  vlib_increment_simple_counter (
+	    vnm->interface_main.sw_if_counters + VNET_INTERFACE_COUNTER_TX_ERROR,
+	    thread_index, tx, 1);
+	  dropped = 1;
+	}
+      else
+	{
+	  u32 fnext = 0;
+	  vnet_feature_next (&fnext, b[0]);
+	  next[0] = (u16) fnext;
+	}
+
+      if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
+			 (b[0]->flags & VLIB_BUFFER_IS_TRACED)))
+	{
+	  ip4_loopback_trace_t *t = vlib_add_trace (vm, node, b[0], sizeof (*t));
+	  t->rx_sw_if_index = rx;
+	  t->tx_sw_if_index = tx;
+	  t->next_index = next[0];
+	  t->dropped = dropped;
+	}
+
+      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_REGISTER_NODE (sonic_ext_ip4_loopback_node) = {
+  .name = "sonic-ext-ip4-loopback",
+  .vector_size = sizeof (u32),
+  .format_trace = format_ip4_loopback_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (ip4_loopback_error_strings),
+  .error_strings = ip4_loopback_error_strings,
+  .n_next_nodes = IP4_LOOPBACK_N_NEXT,
+  .next_nodes = {
+    [IP4_LOOPBACK_NEXT_DROP] = "error-drop",
+    [IP4_LOOPBACK_NEXT_INTERFACE_OUTPUT] = "interface-output",
+  },
+};
+
+VNET_FEATURE_INIT (sonic_ext_ip4_loopback_feat, static) = {
+  .arc_name = "ip4-output",
+  .node_name = "sonic-ext-ip4-loopback",
+  .runs_before = VNET_FEATURES ("interface-output"),
+};

vppbld/plugins/sonic_ext/ip6_loopback_node.c

@@ -0,0 +1,145 @@
+/*
+ * Copyright (c) 2026 SONiC-VPP contributors
+ * 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/feature/feature.h>
+#include <vnet/ip/ip6_packet.h>
+#include <sonic_ext/sonic_ext.h>
+
+typedef struct
+{
+  u32 rx_sw_if_index;
+  u32 tx_sw_if_index;
+  u32 next_index;
+  u8 dropped;
+} ip6_loopback_trace_t;
+
+static u8 *
+format_ip6_loopback_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 *);
+  ip6_loopback_trace_t *t = va_arg (*args, ip6_loopback_trace_t *);
+
+  s = format (s, "SONIC-EXT-IP6-LOOPBACK: rx %d tx %d next %d %s",
+	      t->rx_sw_if_index, t->tx_sw_if_index, t->next_index,
+	      t->dropped ? "(hairpin-drop)" : "");
+  return s;
+}
+
+#define foreach_ip6_loopback_error _ (HAIRPIN_DROP, "hairpin packets dropped")
+
+typedef enum
+{
+#define _(sym, str) IP6_LOOPBACK_ERROR_##sym,
+  foreach_ip6_loopback_error
+#undef _
+    IP6_LOOPBACK_N_ERROR,
+} ip6_loopback_error_t;
+
+static char *ip6_loopback_error_strings[] = {
+#define _(sym, string) string,
+  foreach_ip6_loopback_error
+#undef _
+};
+
+typedef enum
+{
+  IP6_LOOPBACK_NEXT_DROP,
+  IP6_LOOPBACK_NEXT_INTERFACE_OUTPUT,
+  IP6_LOOPBACK_N_NEXT,
+} ip6_loopback_next_t;
+
+VLIB_NODE_FN (sonic_ext_ip6_loopback_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
+{
+  sonic_ext_main_t *sem = &sonic_ext_main;
+  vnet_main_t *vnm = vnet_get_main ();
+  u32 thread_index = vm->thread_index;
+  u32 n_left_from, *from;
+  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
+  u16 nexts[VLIB_FRAME_SIZE], *next;
+
+  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)
+    {
+      u32 rx = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
+      u32 tx = vnet_buffer (b[0])->sw_if_index[VLIB_TX];
+      u8 action = (tx < vec_len (sem->loopback_action_by_sw_if_index))
+		    ? sem->loopback_action_by_sw_if_index[tx]
+		    : SONIC_EXT_LOOPBACK_ACTION_FORWARD;
+      u8 dropped = 0;
+
+      if (PREDICT_FALSE (rx == tx && action == SONIC_EXT_LOOPBACK_ACTION_DROP))
+	{
+	  next[0] = IP6_LOOPBACK_NEXT_DROP;
+	  b[0]->error = node->errors[IP6_LOOPBACK_ERROR_HAIRPIN_DROP];
+	  vlib_increment_simple_counter (
+	    vnm->interface_main.sw_if_counters + VNET_INTERFACE_COUNTER_TX_ERROR,
+	    thread_index, tx, 1);
+	  dropped = 1;
+	}
+      else
+	{
+	  u32 fnext = 0;
+	  vnet_feature_next (&fnext, b[0]);
+	  next[0] = (u16) fnext;
+	}
+
+      if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
+			 (b[0]->flags & VLIB_BUFFER_IS_TRACED)))
+	{
+	  ip6_loopback_trace_t *t = vlib_add_trace (vm, node, b[0], sizeof (*t));
+	  t->rx_sw_if_index = rx;
+	  t->tx_sw_if_index = tx;
+	  t->next_index = next[0];
+	  t->dropped = dropped;
+	}
+
+      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_REGISTER_NODE (sonic_ext_ip6_loopback_node) = {
+  .name = "sonic-ext-ip6-loopback",
+  .vector_size = sizeof (u32),
+  .format_trace = format_ip6_loopback_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (ip6_loopback_error_strings),
+  .error_strings = ip6_loopback_error_strings,
+  .n_next_nodes = IP6_LOOPBACK_N_NEXT,
+  .next_nodes = {
+    [IP6_LOOPBACK_NEXT_DROP] = "error-drop",
+    [IP6_LOOPBACK_NEXT_INTERFACE_OUTPUT] = "interface-output",
+  },
+};
+
+VNET_FEATURE_INIT (sonic_ext_ip6_loopback_feat, static) = {
+  .arc_name = "ip6-output",
+  .node_name = "sonic-ext-ip6-loopback",
+  .runs_before = VNET_FEATURES ("interface-output"),
+};

vppbld/plugins/sonic_ext/sonic_ext.api

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2026 SONiC-VPP contributors
+ * 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.
+ */
+
+option version = "1.0.0";
+import "vnet/interface_types.api";
+
+/** \brief Set the loopback (hairpin) packet action on a router interface
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param sw_if_index - the interface the action applies to
+    @param action - 0 = FORWARD (default), 1 = DROP
+
+    When action is DROP, a routed packet whose ingress interface equals its
+    egress interface (a hairpin) is dropped on the ip4-output / ip6-output arc
+    and the interface tx-error counter is incremented. The node is enabled on
+    the interface's output arcs only while the action is DROP.
+*/
+autoreply define iface_loopback_set_action
+{
+  u32 client_index;
+  u32 context;
+  vl_api_interface_index_t sw_if_index;
+  u8 action;
+};