zebra: add optional extra data about routes' interfaces

Add extra data about the interfaces used in route updates'
nexthops - some consumers of route updates may want additional
data, but dataplane plugins running in the dplane pthread
cannot safely access the normal zebra data structures. Capturing
this info is optional - a plugin must request it (via an api).

Signed-off-by: Mark Stapp <mjs@voltanet.io>

zebra/zebra_dplane.c

@@ -40,12 +40,18 @@
 
 /* Memory type for context blocks */
 DEFINE_MTYPE_STATIC(ZEBRA, DP_CTX, "Zebra DPlane Ctx")
+DEFINE_MTYPE_STATIC(ZEBRA, DP_INTF, "Zebra DPlane Intf")
 DEFINE_MTYPE_STATIC(ZEBRA, DP_PROV, "Zebra DPlane Provider")
 
 #ifndef AOK
 #  define AOK 0
 #endif
 
+/* Control for collection of extra interface info with route updates; a plugin
+ * can enable the extra info via a dplane api.
+ */
+static bool dplane_collect_extra_intf_info;
+
 /* Enable test dataplane provider */
 /*#define DPLANE_TEST_PROVIDER 1 */
 
@@ -84,6 +90,18 @@ struct dplane_nexthop_info {
 	uint8_t nh_grp_count;
 };
 
+/*
+ * Optional extra info about interfaces used in route updates' nexthops.
+ */
+struct dplane_intf_extra {
+	vrf_id_t vrf_id;
+	uint32_t ifindex;
+	uint32_t flags;
+	uint32_t status;
+
+	TAILQ_ENTRY(dplane_intf_extra) link;
+};
+
 /*
  * Route information captured for route updates.
  */
@@ -127,8 +145,8 @@ struct dplane_route_info {
 	struct nexthop_group zd_old_ng;
 	struct nexthop_group old_backup_ng;
 
-	/* TODO -- use fixed array of nexthops, to avoid mallocs? */
-
+	/* Optional list of extra interface info */
+	TAILQ_HEAD(dp_intf_extra_q, dplane_intf_extra) intf_extra_q;
 };
 
 /*
@@ -507,6 +525,8 @@ void dplane_enable_sys_route_notifs(void)
  */
 static void dplane_ctx_free_internal(struct zebra_dplane_ctx *ctx)
 {
+	struct dplane_intf_extra *if_extra, *if_tmp;
+
 	/*
 	 * Some internal allocations may need to be freed, depending on
 	 * the type of info captured in the ctx.
@@ -549,6 +569,14 @@ static void dplane_ctx_free_internal(struct zebra_dplane_ctx *ctx)
 			ctx->u.rinfo.old_backup_ng.nexthop = NULL;
 		}
 
+		/* Optional extra interface info */
+		TAILQ_FOREACH_SAFE(if_extra, &ctx->u.rinfo.intf_extra_q,
+				   link, if_tmp) {
+			TAILQ_REMOVE(&ctx->u.rinfo.intf_extra_q, if_extra,
+				     link);
+			XFREE(MTYPE_DP_INTF, if_extra);
+		}
+
 		break;
 
 	case DPLANE_OP_NH_INSTALL:
@@ -1819,6 +1847,45 @@ dplane_ctx_get_br_port_backup_nhg_id(const struct zebra_dplane_ctx *ctx)
  * End of dplane context accessors
  */
 
+/* Optional extra info about interfaces in nexthops - a plugin must enable
+ * this extra info.
+ */
+const struct dplane_intf_extra *
+dplane_ctx_get_intf_extra(const struct zebra_dplane_ctx *ctx)
+{
+	return TAILQ_FIRST(&ctx->u.rinfo.intf_extra_q);
+}
+
+const struct dplane_intf_extra *
+dplane_ctx_intf_extra_next(const struct zebra_dplane_ctx *ctx,
+			   const struct dplane_intf_extra *ptr)
+{
+	return TAILQ_NEXT(ptr, link);
+}
+
+vrf_id_t dplane_intf_extra_get_vrfid(const struct dplane_intf_extra *ptr)
+{
+	return ptr->vrf_id;
+}
+
+uint32_t dplane_intf_extra_get_ifindex(const struct dplane_intf_extra *ptr)
+{
+	return ptr->ifindex;
+}
+
+uint32_t dplane_intf_extra_get_flags(const struct dplane_intf_extra *ptr)
+{
+	return ptr->flags;
+}
+
+uint32_t dplane_intf_extra_get_status(const struct dplane_intf_extra *ptr)
+{
+	return ptr->status;
+}
+
+/*
+ * End of interface extra info accessors
+ */
 
 /*
  * Retrieve the limit on the number of pending, unprocessed updates.
@@ -1887,10 +1954,14 @@ int dplane_ctx_route_init(struct zebra_dplane_ctx *ctx, enum dplane_op_e op,
 	struct zebra_vrf *zvrf;
 	struct nexthop *nexthop;
 	zebra_l3vni_t *zl3vni;
+	const struct interface *ifp;
+	struct dplane_intf_extra *if_extra;
 
 	if (!ctx || !rn || !re)
 		goto done;
 
+	TAILQ_INIT(&ctx->u.rinfo.intf_extra_q);
+
 	ctx->zd_op = op;
 	ctx->zd_status = ZEBRA_DPLANE_REQUEST_SUCCESS;
 
@@ -1952,6 +2023,27 @@ int dplane_ctx_route_init(struct zebra_dplane_ctx *ctx, enum dplane_op_e op,
 			nexthop->nh_encap_type = NET_VXLAN;
 			nexthop->nh_encap.vni = zl3vni->vni;
 		}
+
+		/* Optionally capture extra interface info while we're in the
+		 * main zebra pthread - a plugin has to ask for this info.
+		 */
+		if (dplane_collect_extra_intf_info) {
+			ifp = if_lookup_by_index(nexthop->ifindex,
+						 nexthop->vrf_id);
+
+			if (ifp) {
+				if_extra = XCALLOC(
+					MTYPE_DP_INTF,
+					sizeof(struct dplane_intf_extra));
+				if_extra->vrf_id = nexthop->vrf_id;
+				if_extra->ifindex = nexthop->ifindex;
+				if_extra->flags = ifp->flags;
+				if_extra->status = ifp->status;
+
+				TAILQ_INSERT_TAIL(&ctx->u.rinfo.intf_extra_q,
+						  if_extra, link);
+			}
+		}
 	}
 
 	/* Don't need some info when capturing a system notification */
@@ -4243,6 +4335,14 @@ bool dplane_is_in_shutdown(void)
 	return zdplane_info.dg_is_shutdown;
 }
 
+/*
+ * Enable collection of extra info about interfaces in route updates.
+ */
+void dplane_enable_intf_extra_info(void)
+{
+	dplane_collect_extra_intf_info = true;
+}
+
 /*
  * Early or pre-shutdown, de-init notification api. This runs pretty
  * early during zebra shutdown, as a signal to stop new work and prepare

zebra/zebra_dplane.h

@@ -204,6 +204,9 @@ void dplane_enable_sys_route_notifs(void);
  */
 TAILQ_HEAD(dplane_ctx_q, zebra_dplane_ctx);
 
+/* Declare a type for (optional) extended interface info objects. */
+TAILQ_HEAD(dplane_intf_extra_q, dplane_intf_extra);
+
 /* Allocate a context object */
 struct zebra_dplane_ctx *dplane_ctx_alloc(void);
 
@@ -313,6 +316,21 @@ const struct nexthop_group *dplane_ctx_get_ng(
 const struct nexthop_group *dplane_ctx_get_old_ng(
 	const struct zebra_dplane_ctx *ctx);
 
+/* Optional extra info about interfaces in nexthops - a plugin must enable
+ * this extra info.
+ */
+const struct dplane_intf_extra *
+dplane_ctx_get_intf_extra(const struct zebra_dplane_ctx *ctx);
+
+const struct dplane_intf_extra *
+dplane_ctx_intf_extra_next(const struct zebra_dplane_ctx *ctx,
+			   const struct dplane_intf_extra *ptr);
+
+vrf_id_t dplane_intf_extra_get_vrfid(const struct dplane_intf_extra *ptr);
+uint32_t dplane_intf_extra_get_ifindex(const struct dplane_intf_extra *ptr);
+uint32_t dplane_intf_extra_get_flags(const struct dplane_intf_extra *ptr);
+uint32_t dplane_intf_extra_get_status(const struct dplane_intf_extra *ptr);
+
 /* Backup nexthop information (list of nexthops) if present. */
 const struct nexthop_group *
 dplane_ctx_get_backup_ng(const struct zebra_dplane_ctx *ctx);
@@ -743,6 +761,12 @@ void dplane_provider_enqueue_out_ctx(struct zebra_dplane_provider *prov,
 /* Enqueue a context directly to zebra main. */
 void dplane_provider_enqueue_to_zebra(struct zebra_dplane_ctx *ctx);
 
+/* Enable collection of extra info about interfaces in route updates;
+ * this allows a provider/plugin to see some extra info in route update
+ * context objects.
+ */
+void dplane_enable_intf_extra_info(void);
+
 /*
  * Initialize the dataplane modules at zebra startup. This is currently called
  * by the rib module. Zebra registers a results callback with the dataplane.