git: f8798767219d - main - Fix IPv4 fib bsearch4() lookup array construction.

[Alexander V. Chernikov]

The branch main has been updated by melifaro:

URL: https://cgit.FreeBSD.org/src/commit/?id=f8798767219ddc5a6dc075b1d2c751ee910e4f10

commit f8798767219ddc5a6dc075b1d2c751ee910e4f10
Author:     Alexander V. Chernikov <melifaro at FreeBSD.org>
AuthorDate: 2021-01-17 19:43:52 +0000
Commit:     Alexander V. Chernikov <melifaro at FreeBSD.org>
CommitDate: 2021-01-17 20:32:26 +0000

    Fix IPv4 fib bsearch4() lookup array construction.
    
    Current code didn't properly handle the case with nested prefixes
     like 10.0.0.0/24 && 10.0.0.0/25.
---
 sys/netinet/in_fib_algo.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/sys/netinet/in_fib_algo.c b/sys/netinet/in_fib_algo.c
index 48e48da395fa..fd817a3fedf0 100644
--- a/sys/netinet/in_fib_algo.c
+++ b/sys/netinet/in_fib_algo.c
@@ -360,6 +360,18 @@ bsearch4_process_record(struct bsearch4_array *dst_array,
 			if (!add_array_entry(dst_array, &new_entry))
 				return (false);
 		 }
+
+		 /*
+		  * Special case: adding more specific prefix at the start of
+		  * the previous interval:
+		  * 10.0.0.0(/24,nh=3), 10.0.0.0(/25,nh=4)
+		  * Alter the last record, seeting new nexthop and mask.
+		  */
+		 if (br_tmp->addr4 == rib_entry->addr4) {
+			*br_tmp = *rib_entry;
+			add_array_entry(stack, rib_entry);
+			return (true);
+		 }
 	 }
 
 	if (!add_array_entry(dst_array, rib_entry))