Re: [PATCH net 1/2] net: ipv4: fix regression in local-broadcast routes
From: Jakub Kicinski <kuba@kernel.org>
Date: 2025-08-25 22:56:31
Also in:
regressions, stable
On Mon, 25 Aug 2025 08:09:17 +0200 Oscar Maes wrote:
Commit 9e30ecf23b1b ("net: ipv4: fix incorrect MTU in broadcast routes")
introduced a regression where local-broadcast packets would have their
gateway set in __mkroute_output, which was caused by fi = NULL being
removed.
Fix this by resetting the fib_info for local-broadcast packets.Meaning that 9e30ecf23b1b would still change behavior for the subnet broadcast address?
quoted hunk ↗ jump to hunk
diff --git a/net/ipv4/route.c b/net/ipv4/route.c index f639a2ae881a..98d237e3ec04 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c@@ -2575,9 +2575,12 @@ static struct rtable *__mkroute_output(const struct fib_result *res, !netif_is_l3_master(dev_out)) return ERR_PTR(-EINVAL); - if (ipv4_is_lbcast(fl4->daddr)) + if (ipv4_is_lbcast(fl4->daddr)) { type = RTN_BROADCAST; - else if (ipv4_is_multicast(fl4->daddr)) + + /* reset fi to prevent gateway resolution */ + fi = NULL; + } else if (ipv4_is_multicast(fl4->daddr)) type = RTN_MULTICAST; else if (ipv4_is_zeronet(fl4->daddr)) return ERR_PTR(-EINVAL);
nit: please add curly braces around all branches of this if / else if / else ladder, per kernel coding style guide. -- pw-bot: cr