[PATCH] Net:cache didn't flush when ipv6 rule changed

["Lena Wang (王娜)" <Lena.Wang@mediatek.com>]

From a415abaf4fc90a27dd86357ea8be62d32956f7d8 Mon Sep 17 00:00:00 2001
From: shiming cheng <shiming.cheng@mediatek.com>
Date: Mon, 26 Feb 2024 20:17:58 +0800
Subject: [PATCH] Net:cache didn't flush when ipv6 rule changed

When changed from old rule&route configure to new one as below,
ipv6 cache dst_entry did not change to new route table as no
cache flush callback function, then forward to wrong out interface.
When fib6_check dst_entry, the fib6_node version[fn_sernm] is
always the same with socket dst_cookie, old cache dst_entry is
always used and no chance to update.

So we need to update fib6_node version when rule changed and
flush cache to avoid dispatching a wrong interface.

Signed-off-by: shiming cheng <shiming.cheng@mediatek.com>
---
 net/ipv6/fib6_rules.c | 10 ++++++++++
 1 files changed, 10 insertions(+)

diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
index 7523c4baef35..bec2cf4436e1 100644
--- a/net/ipv6/fib6_rules.c
+++ b/net/ipv6/fib6_rules.c
@@ -449,6 +449,15 @@ static size_t fib6_rule_nlmsg_payload(struct
fib_rule *rule)
               + nla_total_size(16); /* src */
 }

+static void fib6_rule_flush_cache(struct fib_rules_ops *ops)
+{
+       struct net *net = ops->fro_net;
+       if (!net)
+               return;
+       rt_genid_bump_ipv6(net);
+       return;
+}
+
 static const struct fib_rules_ops __net_initconst
fib6_rules_ops_template = {
        .family                 = AF_INET6,
        .rule_size              = sizeof(struct fib6_rule),
@@ -461,6 +470,7 @@ static const struct fib_rules_ops __net_initconst
fib6_rules_ops_template = {
        .compare                = fib6_rule_compare,
        .fill                   = fib6_rule_fill,
        .nlmsg_payload          = fib6_rule_nlmsg_payload,
+       .flush_cache    = fib6_rule_flush_cache,
        .nlgroup                = RTNLGRP_IPV6_RULE,
        .owner                  = THIS_MODULE,
        .fro_net                = &init_net,
--
2.18.0