Static: Minor overhaul

The patch fixes several bugs introduced in previous changes, simplifies
the protocol by handing routes uniformly, introduces asynchronous route
processing to avoid issues with separate notifications for each next-hop
in ECMP routes, and makes reconfiguration faster by avoiding quadratic
complexity.

lib/buffer.h

@@ -14,7 +14,7 @@
 #include "sysdep/config.h"
 
 #define BUFFER(type)		struct { type *data; uint used, size; }
-
+#define BUFFER_TYPE(v)		typeof(* (v).data)
 #define BUFFER_SIZE(v)		((v).size * sizeof(* (v).data))
 
 #define BUFFER_INIT(v,pool,isize)					\
@@ -46,6 +46,9 @@
 
 #define BUFFER_FLUSH(v)		({ (v).used = 0; })
 
+#define BUFFER_WALK(v,n)						\
+  for (BUFFER_TYPE(v) *_n = (v).data, n; _n < ((v).data + (v).used) && (n = *_n, 1); _n++)
+
 #define BUFFER_SHALLOW_COPY(dst, src)					\
   ({									\
     (dst).used = (src).used;						\

lib/buffer_test.c

@@ -133,6 +133,25 @@ t_buffer_flush(void)
   return 1;
 }
 
+static int
+t_buffer_walk(void)
+{
+  int i;
+
+  init_buffer();
+  fill_expected_array();
+  for (i = 0; i < MAX_NUM; i++)
+    BUFFER_PUSH(buf) = expected[i];
+
+  i = 0;
+  BUFFER_WALK(buf, v)
+    bt_assert(v == expected[i++]);
+
+  bt_assert(i == MAX_NUM);
+
+  return 1;
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -142,6 +161,7 @@ main(int argc, char *argv[])
   bt_test_suite(t_buffer_pop, "Fill whole buffer (PUSH), a half of elements POP and PUSH new elements");
   bt_test_suite(t_buffer_resize, "Init a small buffer and try overfill");
   bt_test_suite(t_buffer_flush, "Fill and flush all elements");
+  bt_test_suite(t_buffer_walk, "Fill and walk through buffer");
 
   return bt_exit_value();
 }

proto/static/config.Y

@@ -19,15 +19,9 @@ static struct f_inst **this_srt_last_cmd;
 static struct static_route *
 static_nexthop_new(void)
 {
-  struct static_route *nh;
+  struct static_route *nh = this_srt;
 
-  if (!this_snh)
-  {
-    /* First next hop */
-    nh = this_srt;
-    rem_node(&this_srt->n);
-  }
-  else
+  if (this_snh)
   {
     /* Additional next hop */
     nh = cfg_allocz(sizeof(struct static_route));
@@ -57,7 +51,7 @@ CF_ADDTO(proto, static_proto '}')
 static_proto_start: proto_start STATIC
 {
   this_proto = proto_config_new(&proto_static, $1);
-  static_init_config(STATIC_CFG);
+  init_list(&STATIC_CFG->routes);
 };
 
 static_proto:
@@ -74,13 +68,11 @@ stat_nexthop:
       this_snh = static_nexthop_new();
       this_snh->via = $2;
       this_snh->iface = $3;
-      add_tail(&STATIC_CFG->neigh_routes, &this_snh->n);
     }
   | VIA TEXT {
       this_snh = static_nexthop_new();
       this_snh->via = IPA_NONE;
-      this_snh->if_name = $2;
-      add_tail(&STATIC_CFG->iface_routes, &this_snh->n);
+      this_snh->iface = if_get_by_name($2);
     }
   | stat_nexthop MPLS label_stack {
     this_snh->label_count = $3[0];
@@ -102,7 +94,7 @@ stat_nexthops:
 
 stat_route0: ROUTE net_any {
      this_srt = cfg_allocz(sizeof(struct static_route));
-     add_tail(&STATIC_CFG->other_routes, &this_srt->n);
+     add_tail(&STATIC_CFG->routes, &this_srt->n);
      this_srt->net = $2;
      this_srt_last_cmd = &(this_srt->cmds);
      this_srt->mp_next = NULL;

proto/static/static.h

@@ -11,49 +11,58 @@
 
 #include "nest/route.h"
 #include "nest/bfd.h"
+#include "lib/buffer.h"
 
 struct static_config {
   struct proto_config c;
-  list iface_routes;		/* Routes to search on interface events */
-  list neigh_routes;		/* Routes to search on neighbor events */
-  list other_routes;		/* Non-nexthop routes */
+  list routes;				/* List of static routes (struct static_route) */
   int check_link;			/* Whether iface link state is used */
   struct rtable_config *igp_table;	/* Table used for recursive next hop lookups */
 };
 
+struct static_proto {
+  struct proto p;
 
-void static_init_config(struct static_config *);
+  struct event *event;			/* Event for announcing updated routes */
+  BUFFER(struct static_route *) marked;	/* Routes marked for reannouncement */
+};
 
 struct static_route {
   node n;
-  struct static_route *chain;		/* Next for the same neighbor */
   net_addr *net;			/* Network we route */
-  int dest;				/* Destination type (RTD_*) */
   ip_addr via;				/* Destination router */
   struct iface *iface;			/* Destination iface, for link-local vias or device routes */
-  struct neighbor *neigh;
-  byte *if_name;			/* Name for device routes */
-  struct static_route *mp_next;		/* Nexthops for multipath routes */
+  struct neighbor *neigh;		/* Associated neighbor entry */
+  struct static_route *chain;		/* Next for the same neighbor */
   struct static_route *mp_head;		/* First nexthop of this route */
+  struct static_route *mp_next;		/* Nexthops for multipath routes */
   struct f_inst *cmds;			/* List of commands for setting attributes */
-  u32 state;				/* Current state: STS_* */
-  int weight;				/* Multipath next hop weight */
+  byte dest;				/* Destination type (RTD_*) */
+  byte state;				/* State of route announcement (SRS_*) */
+  byte active;				/* Next hop is active (nbr/iface/BFD available) */
+  byte weight;				/* Multipath next hop weight */
   byte use_bfd;				/* Configured to use BFD */
   byte label_count;			/* Number of labels in stack */
   struct bfd_request *bfd_req;		/* BFD request, if BFD is used */
   u32 *label_stack;			/* Label stack if label_count > 0 */
 };
 
-#define STS_INSTALLED		0x1
-#define STS_WANT		0x2
-#define STS_FORCE		0x4
-
-/* Dummy nodes (parts of multipath route) abuses masklen field for weight
-   and if_name field for a ptr to the master (RTD_MULTIPATH) node. */
-
+/*
+ * Note that data fields neigh, chain, state, active and bfd_req are runtime
+ * data, not real configuration data. Must be handled carefully.
+ *
+ * Regular (i.e. dest == RTD_UNICAST) routes use static_route structure for
+ * additional next hops (fields mp_head, mp_next). Note that 'state' is for
+ * whole route, while 'active' is for each next hop. Also note that fields
+ * mp_head, mp_next, active are zero for other kinds of routes.
+ */
 
 #define RTDX_RECURSIVE 0x7f		/* Phony dest value for recursive routes */
 
+#define SRS_DOWN	0		/* Route is not announced */
+#define SRS_CLEAN	1		/* Route is active and announced */
+#define SRS_DIRTY	2		/* Route changed since announcement */
+
 void static_show(struct proto *);
 
 #endif