Nest: Allow modification of channels inherited from templates

Multiple definitions of same channels are forbidden, but inherited
channel can be redefined. In such case channel options are merged.

3 files changed, 26 insertions, 5 deletions

diff --git a/nest/config.Y b/nest/config.Y
index 5c4f2393..044aba2b 100644
--- a/nest/config.Y
+++ b/nest/config.Y
@@ -214,7 +214,7 @@ proto_item:
 
 channel_start: net_type
 {
-  $$ = this_channel = channel_config_new(NULL, $1, this_proto);
+  $$ = this_channel = channel_config_get(NULL, net_label[$1], $1, this_proto);
 };
 
 channel_item:
diff --git a/nest/proto.c b/nest/proto.c
index e103fec6..d584cb93 100644
--- a/nest/proto.c
+++ b/nest/proto.c
@@ -455,11 +455,10 @@ const struct channel_class channel_basic = {
 };
 
 void *
-channel_config_new(const struct channel_class *cc, uint net_type, struct proto_config *proto)
+channel_config_new(const struct channel_class *cc, const char *name, uint net_type, struct proto_config *proto)
 {
   struct channel_config *cf = NULL;
   struct rtable_config *tab = NULL;
-  const char *name = NULL;
 
   if (net_type)
   {
@@ -470,7 +469,6 @@ channel_config_new(const struct channel_class *cc, uint net_type, struct proto_c
       cf_error("Different channel type");
 
     tab = new_config->def_tables[net_type];
-    name = net_label[net_type];
   }
 
   if (!cc)
@@ -479,6 +477,7 @@ channel_config_new(const struct channel_class *cc, uint net_type, struct proto_c
   cf = cfg_allocz(cc->config_size);
   cf->name = name;
   cf->channel = cc;
+  cf->parent = proto;
   cf->table = tab;
   cf->out_filter = FILTER_REJECT;
 
@@ -491,6 +490,26 @@ channel_config_new(const struct channel_class *cc, uint net_type, struct proto_c
   return cf;
 }
 
+void *
+channel_config_get(const struct channel_class *cc, const char *name, uint net_type, struct proto_config *proto)
+{
+  struct channel_config *cf;
+
+  /* We are using name as token, so no strcmp() */
+  WALK_LIST(cf, proto->channels)
+    if (cf->name == name)
+    {
+      /* Allow to redefine channel only if inherited from template */
+      if (cf->parent == proto)
+	cf_error("Multiple %s channels", name);
+
+      cf->parent = proto;
+      return cf;
+    }
+
+  return channel_config_new(cc, name, net_type, proto);
+}
+
 struct channel_config *
 channel_copy_config(struct channel_config *src, struct proto_config *proto)
 {
diff --git a/nest/protocol.h b/nest/protocol.h
index c8f37367..9afd3a0a 100644
--- a/nest/protocol.h
+++ b/nest/protocol.h
@@ -461,6 +461,7 @@ struct channel_config {
   const char *name;
   const struct channel_class *channel;
 
+  struct proto_config *parent;		/* Where channel is defined (proto or template) */
   struct rtable_config *table;		/* Table we're attached to */
   struct filter *in_filter, *out_filter; /* Attached filters */
   struct channel_limit rx_limit;	/* Limit for receiving routes from protocol
@@ -585,7 +586,8 @@ static inline void channel_open(struct channel *c) { channel_set_state(c, CS_UP)
 static inline void channel_close(struct channel *c) { channel_set_state(c, CS_FLUSHING); }
 
 void channel_request_feeding(struct channel *c);
-void *channel_config_new(const struct channel_class *cc, uint net_type, struct proto_config *proto);
+void *channel_config_new(const struct channel_class *cc, const char *name, uint net_type, struct proto_config *proto);
+void *channel_config_get(const struct channel_class *cc, const char *name, uint net_type, struct proto_config *proto);
 int channel_reconfigure(struct channel *c, struct channel_config *cf);