6.17-stable review patch. If anyone has any objections, please let me know.
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From: Oscar Maes oscmaes92@gmail.com
[ Upstream commit 1b8c5fa0cb35efd08f07f700e6d78a541ebabe26 ]
Currently, ip_extract_route_hint uses RTN_BROADCAST to decide whether to use the route dst hint mechanism.
This check is too strict, as it prevents directed broadcast routes from using the hint, resulting in poor performance during bursts of directed broadcast traffic.
Fix this in ip_extract_route_hint and modify ip_route_use_hint to preserve the intended behaviour.
Signed-off-by: Oscar Maes oscmaes92@gmail.com Reviewed-by: David Ahern dsahern@kernel.org Link: https://patch.msgid.link/20250819174642.5148-2-oscmaes92@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv4/ip_input.c | 11 +++++++---- net/ipv4/route.c | 2 +- 2 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c index fc323994b1fa0..a09aca2c8567d 100644 --- a/net/ipv4/ip_input.c +++ b/net/ipv4/ip_input.c @@ -587,9 +587,13 @@ static void ip_sublist_rcv_finish(struct list_head *head) }
static struct sk_buff *ip_extract_route_hint(const struct net *net, - struct sk_buff *skb, int rt_type) + struct sk_buff *skb) { - if (fib4_has_custom_rules(net) || rt_type == RTN_BROADCAST || + const struct iphdr *iph = ip_hdr(skb); + + if (fib4_has_custom_rules(net) || + ipv4_is_lbcast(iph->daddr) || + ipv4_is_zeronet(iph->daddr) || IPCB(skb)->flags & IPSKB_MULTIPATH) return NULL;
@@ -618,8 +622,7 @@ static void ip_list_rcv_finish(struct net *net, struct list_head *head)
dst = skb_dst(skb); if (curr_dst != dst) { - hint = ip_extract_route_hint(net, skb, - dst_rtable(dst)->rt_type); + hint = ip_extract_route_hint(net, skb);
/* dispatch old sublist */ if (!list_empty(&sublist)) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 5582ccd673eeb..86a20d12472f4 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2210,7 +2210,7 @@ ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr, goto martian_source; }
- if (rt->rt_type != RTN_LOCAL) + if (!(rt->rt_flags & RTCF_LOCAL)) goto skip_validate_source;
reason = fib_validate_source_reason(skb, saddr, daddr, dscp, 0, dev,