Doc: Migration guide updated about onlink and from route attributes

The onlink route attribute has been fixed.

The from route attribute changed behavior slightly
between BIRD 2 and 3 so it is now described in the
migration guide.

Related to #258 and #262.

diff --git a/doc/migration-bird3.md b/doc/migration-bird3.md
index 6098c10fbb40d8a1337802ac2b174115cd4aec64..af487109b148d35d9da954585cb133c1a1ca4511 100644 (file)
--- a/doc/migration-bird3.md
+++ b/doc/migration-bird3.md
@@ -72,11 +72,12 @@ All protocol attributes have been renamed in CLI to align with the filter langua
 Output of `show route all` also shows more information, including some internal
 data for easier debugging and route tracing.
 
-The `onlink` route attribute has been temporarily disabled until we find out
-how to implement it properly.
-
 The `scope` route attribute has been removed. Use custom route attributes instead.
 
+The `from` route attribute is set only if it's relevant, therefore some of
+the filters may refuse to process routes if relying on the default zero value.
+Now it's possible to check for `defined(from)` in filters before using it.
+
 ## Protocols common
 
 There is now a guard against too frequent restarts due to limits, called