Bugfixes in MULIT_EXIT_DISC attribute handling.

 - Old MED handling was completely different from behavior
   specified in RFCs - for example they havn't been propagated
   to neighboring areas.

 - Update tie-breaking according to RFC 4271.

 - Change default value for 'default bgp_med' configuration
   option according to RFC 4271.

2 files changed, 15 insertions, 0 deletions

diff --git a/nest/a-path.c b/nest/a-path.c
index f4666911..5e3ecfd4 100644
--- a/nest/a-path.c
+++ b/nest/a-path.c
@@ -244,6 +244,20 @@ as_path_get_first(struct adata *path, u32 *orig_as)
 }
 
 int
+as_path_get_last(struct adata *path, u32 *last_as)
+{
+  u8 *p = path->data;
+
+  if ((path->length == 0) || (p[0] != AS_PATH_SEQUENCE) || (p[1] == 0))
+    return 0;
+  else
+    {
+      *last_as = get_as(p+2);
+      return 1;
+    }
+}
+
+int
 as_path_is_member(struct adata *path, u32 as)
 {
   int bs = bgp_as4_support ? 4 : 2;
diff --git a/nest/attrs.h b/nest/attrs.h
index aaa5f4a2..fee2c2c8 100644
--- a/nest/attrs.h
+++ b/nest/attrs.h
@@ -27,6 +27,7 @@ int as_path_convert_to_new(struct adata *path, byte *dst, int req_as);
 void as_path_format(struct adata *path, byte *buf, unsigned int size);
 int as_path_getlen(struct adata *path);
 int as_path_get_first(struct adata *path, u32 *orig_as);
+int as_path_get_last(struct adata *path, u32 *last_as);
 int as_path_is_member(struct adata *path, u32 as);