Implements protocol templates.

Based on the patch from Alexander V. Chernikov.
Extended to support almost all protocols.
Uses 'protocol bgp NAME from TEMPLATE { ... }' syntax.

nest/config.Y

@@ -26,7 +26,7 @@ static int password_id;
 static inline void
 reset_passwords(void)
 {
- this_p_list = NULL;
+  this_p_list = NULL;
 }
 
 static inline list *
@@ -37,10 +37,11 @@ get_passwords(void)
   return rv;
 }
 
+#define DIRECT_CFG ((struct rt_dev_config *) this_proto)
 
 CF_DECLS
 
-CF_KEYWORDS(ROUTER, ID, PROTOCOL, PREFERENCE, DISABLED, DEBUG, ALL, OFF, DIRECT)
+CF_KEYWORDS(ROUTER, ID, PROTOCOL, TEMPLATE, PREFERENCE, DISABLED, DEBUG, ALL, OFF, DIRECT)
 CF_KEYWORDS(INTERFACE, IMPORT, EXPORT, FILTER, NONE, TABLE, STATES, ROUTES, FILTERS)
 CF_KEYWORDS(PASSWORD, FROM, PASSIVE, TO, ID, EVENTS, PACKETS, PROTOCOLS, INTERFACES)
 CF_KEYWORDS(PRIMARY, STATS, COUNT, FOR, COMMANDS, PREEXPORT, GENERATE)
@@ -58,7 +59,7 @@ CF_ENUM(T_ENUM_RTD, RTD_, ROUTER, DEVICE, BLACKHOLE, UNREACHABLE, PROHIBIT, MULT
 %type <r> rtable
 %type <s> optsym
 %type <ra> r_args
-%type <i> echo_mask echo_size debug_mask debug_list debug_flag mrtdump_mask mrtdump_list mrtdump_flag export_or_preexport
+%type <i> proto_start echo_mask echo_size debug_mask debug_list debug_flag mrtdump_mask mrtdump_list mrtdump_flag export_or_preexport
 %type <ps> proto_patt proto_patt2
 
 CF_GRAMMAR
@@ -115,20 +116,30 @@ newtab: TABLE SYM {
 
 CF_ADDTO(conf, proto)
 
-proto_start: PROTOCOL
+proto_start:
+   PROTOCOL { $$ = SYM_PROTO; }
+ | TEMPLATE { $$ = SYM_TEMPLATE; }
  ;
 
 proto_name:
    /* EMPTY */ {
      struct symbol *s = cf_default_name(this_proto->protocol->template, &this_proto->protocol->name_counter);
-     s->class = SYM_PROTO;
+     s->class = this_proto->class;
      s->def = this_proto;
      this_proto->name = s->name;
      }
  | SYM {
-     cf_define_symbol($1, SYM_PROTO, this_proto);
+     cf_define_symbol($1, this_proto->class, this_proto);
      this_proto->name = $1->name;
    }
+ | SYM FROM SYM {
+     if (($3->class != SYM_TEMPLATE) && ($3->class != SYM_PROTO)) cf_error("Template or protocol name expected");
+
+     cf_define_symbol($1, this_proto->class, this_proto);
+     this_proto->name = $1->name;
+
+     proto_copy_config(this_proto, $3->def);
+   }
  ;
 
 proto_item:
@@ -207,10 +218,9 @@ iface_patt_list:
 CF_ADDTO(proto, dev_proto '}')
 
 dev_proto_start: proto_start DIRECT {
-     struct rt_dev_config *p = proto_config_new(&proto_device, sizeof(struct rt_dev_config));
-     this_proto = &p->c;
-     p->c.preference = DEF_PREF_DIRECT;
-     init_list(&p->iface_list);
+     this_proto = proto_config_new(&proto_device, sizeof(struct rt_dev_config), $1);
+     this_proto->preference = DEF_PREF_DIRECT;
+     init_list(&DIRECT_CFG->iface_list);
    }
  ;
 
@@ -222,9 +232,8 @@ dev_proto:
 
 dev_iface_init:
    /* EMPTY */ {
-     struct rt_dev_config *p = (void *) this_proto;
      this_ipatt = cfg_allocz(sizeof(struct iface_patt));
-     add_tail(&p->iface_list, NODE this_ipatt);
+     add_tail(&DIRECT_CFG->iface_list, NODE this_ipatt);
      init_list(&this_ipatt->ipn_list);
    }
  ;

nest/proto.c

@@ -175,6 +175,7 @@ proto_flush_hooks(struct proto *p)
  * proto_config_new - create a new protocol configuration
  * @pr: protocol the configuration will belong to
  * @size: size of the structure including generic data
+ * @class: SYM_PROTO or SYM_TEMPLATE
  *
  * Whenever the configuration file says that a new instance
  * of a routing protocol should be created, the parser calls
@@ -183,16 +184,23 @@ proto_flush_hooks(struct proto *p)
  * containing all the generic items followed by protocol-specific
  * ones). Also, the configuration entry gets added to the list
  * of protocol instances kept in the configuration.
+ *
+ * The function is also used to create protocol templates (when class
+ * SYM_TEMPLATE is specified), the only difference is that templates
+ * are not added to the list of protocol instances and therefore not
+ * initialized during protos_commit()).
  */
 void *
-proto_config_new(struct protocol *pr, unsigned size)
+proto_config_new(struct protocol *pr, unsigned size, int class)
 {
   struct proto_config *c = cfg_allocz(size);
 
-  add_tail(&new_config->protos, &c->n);
+  if (class == SYM_PROTO)
+    add_tail(&new_config->protos, &c->n);
   c->global = new_config;
   c->protocol = pr;
   c->name = pr->name;
+  c->class = class;
   c->out_filter = FILTER_REJECT;
   c->table = c->global->master_rtc;
   c->debug = new_config->proto_default_debug;
@@ -200,6 +208,50 @@ proto_config_new(struct protocol *pr, unsigned size)
   return c;
 }
 
+/**
+ * proto_copy_config - copy a protocol configuration
+ * @dest: destination protocol configuration
+ * @src: source protocol configuration
+ *
+ * Whenever a new instance of a routing protocol is created from the
+ * template, proto_copy_config() is called to copy a content of
+ * the source protocol configuration to the new protocol configuration.
+ * Name, class and a node in protos list of @dest are kept intact.
+ * copy_config() protocol hook is used to copy protocol-specific data.
+ */
+void
+proto_copy_config(struct proto_config *dest, struct proto_config *src)
+{
+  node old_node;
+  int old_class;
+  char *old_name;
+
+  if (dest->protocol != src->protocol)
+    cf_error("Can't copy configuration from a different protocol type");
+
+  if (dest->protocol->copy_config == NULL)
+    cf_error("Inheriting configuration for %s is not supported", src->protocol->name);
+
+  DBG("Copying configuration from %s to %s\n", src->name, dest->name);
+
+  /* 
+   * Copy struct proto_config here. Keep original node, class and name.
+   * protocol-specific config copy is handled by protocol copy_config() hook
+   */
+
+  old_node = dest->n;
+  old_class = dest->class;
+  old_name = dest->name;
+
+  memcpy(dest, src, sizeof(struct proto_config));
+
+  dest->n = old_node;
+  dest->class = old_class;
+  dest->name = old_name;
+
+  dest->protocol->copy_config(dest, src);
+}
+
 /**
  * protos_preconfig - pre-configuration processing
  * @c: new configuration
@@ -230,7 +282,8 @@ protos_preconfig(struct config *c)
  * @c: new configuration
  *
  * This function calls the postconfig() hooks of all protocol
- * instances specified in configuration @c.
+ * instances specified in configuration @c. The hooks are not
+ * called for protocol templates.
  */
 void
 protos_postconfig(struct config *c)
@@ -366,14 +419,15 @@ protos_commit(struct config *new, struct config *old, int force_reconfig, int ty
 {
   struct proto_config *oc, *nc;
   struct proto *p, *n;
+  struct symbol *sym;
 
   DBG("protos_commit:\n");
   if (old)
     {
       WALK_LIST(oc, old->protos)
 	{
-	  struct proto *p = oc->proto;
-	  struct symbol *sym = cf_find_symbol(oc->name);
+	  p = oc->proto;
+	  sym = cf_find_symbol(oc->name);
 	  if (sym && sym->class == SYM_PROTO && !new->shutdown)
 	    {
 	      /* Found match, let's check if we can smoothly switch to new configuration */

nest/protocol.h

@@ -53,6 +53,7 @@ struct protocol {
   void (*get_route_info)(struct rte *, byte *buf, struct ea_list *attrs); /* Get route information (for `show route' command) */
   int (*get_attr)(struct eattr *, byte *buf, int buflen);	/* ASCIIfy dynamic attribute (returns GA_*) */
   void (*show_proto_info)(struct proto *);	/* Show protocol info (for `show protocols all' command) */
+  void (*copy_config)(struct proto_config *, struct proto_config *);	/* Copy config from given protocol instance */
 };
 
 void protos_build(void);
@@ -85,12 +86,15 @@ struct proto_config {
   struct proto *proto;			/* Instance we've created */
   char *name;
   char *dsc;
+  int class;				/* SYM_PROTO or SYM_TEMPLATE */
   u32 debug, mrtdump;			/* Debugging bitfields, both use D_* constants */
   unsigned preference, disabled;	/* Generic parameters */
   u32 router_id;			/* Protocol specific router ID */
   struct rtable_config *table;		/* Table we're attached to */
   struct filter *in_filter, *out_filter; /* Attached filters */
 
+  /* Check proto_reconfigure() and proto_copy_config() after changing struct proto_config */
+
   /* Protocol-specific data follow... */
 };
 
@@ -203,9 +207,14 @@ struct proto_spec {
 
 
 void *proto_new(struct proto_config *, unsigned size);
-void *proto_config_new(struct protocol *, unsigned size);
+void *proto_config_new(struct protocol *, unsigned size, int class);
+void proto_copy_config(struct proto_config *dest, struct proto_config *src);
 void proto_request_feeding(struct proto *p);
 
+static inline void
+proto_copy_rest(struct proto_config *dest, struct proto_config *src, unsigned size)
+{ memcpy(dest + 1, src + 1, size - sizeof(struct proto_config)); }
+
 void proto_cmd_show(struct proto *, unsigned int, int);
 void proto_cmd_disable(struct proto *, unsigned int, int);
 void proto_cmd_enable(struct proto *, unsigned int, int);

nest/rt-dev.c

@@ -92,9 +92,24 @@ dev_reconfigure(struct proto *p, struct proto_config *new)
   return iface_patts_equal(&o->iface_list, &n->iface_list, NULL);
 }
 
+static void
+dev_copy_config(struct proto_config *dest, struct proto_config *src)
+{
+  struct rt_dev_config *d = (struct rt_dev_config *) dest;
+  struct rt_dev_config *s = (struct rt_dev_config *) src;
+
+  /*
+   * We copy iface_list as ifaces can be shared by more direct protocols.
+   * Copy suffices to be is shallow, because new nodes can be added, but
+   * old nodes cannot be modified (although they contain internal lists).
+   */
+  cfg_copy_list(&d->iface_list, &s->iface_list, sizeof(struct iface_patt));
+}
+
 struct protocol proto_device = {
   name:		"Direct",
   template:	"direct%d",
   init:		dev_init,
-  reconfigure:	dev_reconfigure
+  reconfigure:	dev_reconfigure,
+  copy_config:	dev_copy_config
 };

nest/rt-dev.h

@@ -11,7 +11,7 @@
 
 struct rt_dev_config {
   struct proto_config c;
-  list iface_list;
+  list iface_list;		/* list of struct iface_patt */
 };
 
 #endif