[PATCH net v3] ipv6:flush ipv6 route cache when rule is changed

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

From: Shiming Cheng <shiming.cheng@mediatek.com>

When rule policy is changed, ipv6 socket cache is not refreshed.
The sock's skb still uses a outdated route cache and was sent to
a wrong interface.

To avoid this error we should update fib node's version when
rule is changed. Then skb's route will be reroute checked as
route cache version is already different with fib node version.
The route cache is refreshed to match the latest rule.

Signed-off-by: Shiming Cheng <shiming.cheng@mediatek.com>
Signed-off-by: Lena Wang <lena.wang@mediatek.com>
---
v3: Changes according to Jiri's suggestions, update patch
description and name format in commit message.

v2: Changes according to David Ahern's suggestions, modify
flush function same way as ipv4 flush cache and use tabs
to aligh with existing code.
---
---
 net/ipv6/fib6_rules.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
index 7523c4baef35..52c04f0ac498 100644
--- a/net/ipv6/fib6_rules.c
+++ b/net/ipv6/fib6_rules.c
@@ -449,6 +449,11 @@ 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)
+{
+	rt_genid_bump_ipv6(ops->fro_net);
+}
+
 static const struct fib_rules_ops __net_initconst
fib6_rules_ops_template = {
 	.family			= AF_INET6,
 	.rule_size		= sizeof(struct fib6_rule),
@@ -461,6 +466,7 @@ 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