From 3b56bf8849283977f2f4fa7b8f3dc62fdd8d7587 Mon Sep 17 00:00:00 2001
From: "Ondrej Zajicek (work)" <santiago@crfreenet.org>
Date: Thu, 12 Nov 2020 04:02:38 +0100
Subject: [PATCH] BFD: Better handling of BFD options in BGP configs

Merge multiple BFD option blocks in BGP configs instead of using the last
one. That is necessary for proper handling of templates when BFD options
are used both in a BGP template and in a BGP protocol derived from that
template.
---
 conf/confbase.Y    |  1 -
 nest/config.Y      | 25 +++++++++++++++++++++++--
 proto/bgp/bgp.h    |  2 +-
 proto/bgp/config.Y |  6 +++---
 4 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/conf/confbase.Y b/conf/confbase.Y
index f76dcb3c..f0343a93 100644
--- a/conf/confbase.Y
+++ b/conf/confbase.Y
@@ -79,7 +79,6 @@ CF_DECLS
   struct f_trie *trie;
   struct f_val v;
   struct password_item *p;
-  struct bfd_options *bo;
   struct rt_show_data *ra;
   struct sym_show_data *sd;
   struct lsadb_show_data *ld;
diff --git a/nest/config.Y b/nest/config.Y
index 73556f15..83f2c7ba 100644
--- a/nest/config.Y
+++ b/nest/config.Y
@@ -52,6 +52,28 @@ get_passwords(void)
   return rv;
 }
 
+static inline void
+init_bfd_opts(struct bfd_options **opts)
+{
+  cf_check_bfd(1);
+
+  if (! *opts)
+    *opts = bfd_new_options();
+}
+
+static inline void
+open_bfd_opts(struct bfd_options **opts)
+{
+  init_bfd_opts(opts);
+  this_bfd_opts = *opts;
+}
+
+static inline void
+close_bfd_opts(void)
+{
+  this_bfd_opts = NULL;
+}
+
 static void
 proto_postconfig(void)
 {
@@ -99,7 +121,6 @@ CF_ENUM_PX(T_ENUM_AF, AF_, AFI_, IPV4, IPV6)
 %type <ps> proto_patt proto_patt2
 %type <cc> channel_start proto_channel
 %type <cl> limit_spec
-%type <bo> bfd_opts
 %type <net> r_args_for_val
 %type <net_ptr> r_args_for
 %type <t> r_args_channel
@@ -519,7 +540,7 @@ bfd_items:
  ;
 
 bfd_opts:
- '{' { this_bfd_opts = bfd_new_options(); } bfd_items '}' { $$ = this_bfd_opts; this_bfd_opts = NULL; }
+   '{' bfd_items '}'
  ;
 
 /* Core commands */
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index 5f365fcd..ff52a1a1 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -130,7 +130,7 @@ struct bgp_config {
   const char *dynamic_name;		/* Name pattern for dynamic BGP */
   int dynamic_name_digits;		/* Minimum number of digits for dynamic names */
   int check_link;			/* Use iface link state for liveness detection */
-  const struct bfd_options *bfd;	/* Use BFD for liveness detection */
+  struct bfd_options *bfd;		/* Use BFD for liveness detection */
 };
 
 struct bgp_channel_config {
diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y
index dc295645..cc83bfc7 100644
--- a/proto/bgp/config.Y
+++ b/proto/bgp/config.Y
@@ -190,9 +190,9 @@ bgp_proto:
  | bgp_proto LONG LIVED STALE TIME expr ';' { BGP_CFG->llgr_time = $6; }
  | bgp_proto TTL SECURITY bool ';' { BGP_CFG->ttl_security = $4; }
  | bgp_proto CHECK LINK bool ';' { BGP_CFG->check_link = $4; }
- | bgp_proto BFD bool ';' { cf_check_bfd($3); BGP_CFG->bfd = $3 ? bfd_new_options() : NULL; }
- | bgp_proto BFD GRACEFUL ';' { cf_check_bfd(1); struct bfd_options *opts = bfd_new_options(); opts->mode = BGP_BFD_GRACEFUL; BGP_CFG->bfd = opts; }
- | bgp_proto BFD bfd_opts ';' { BGP_CFG->bfd = $3; cf_check_bfd(1); }
+ | bgp_proto BFD bool ';' { if ($3) init_bfd_opts(&BGP_CFG->bfd); else BGP_CFG->bfd = NULL; }
+ | bgp_proto BFD GRACEFUL ';' { init_bfd_opts(&BGP_CFG->bfd); BGP_CFG->bfd->mode = BGP_BFD_GRACEFUL; }
+ | bgp_proto BFD { open_bfd_opts(&BGP_CFG->bfd); } bfd_opts { close_bfd_opts(); } ';'
  | bgp_proto ENFORCE FIRST AS bool ';' { BGP_CFG->enforce_first_as = $5; }
  ;