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net/ipv6: set expires in rt6_add_dflt_router().

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Pass the duration of a lifetime (in seconds) to the function
rt6_add_dflt_router() so that it can properly set the expiration time.

The function ndisc_router_discovery() is the only one that calls
rt6_add_dflt_router(), and it will later set the expiration time for the
route created by rt6_add_dflt_router(). However, there is a gap of time
between calling rt6_add_dflt_router() and setting the expiration time in
ndisc_router_discovery(). During this period, there is a possibility that a
new route may be removed from the routing table. By setting the correct
expiration time in rt6_add_dflt_router(), we can prevent this from
happening. The reason for setting RTF_EXPIRES in rt6_add_dflt_router() is
to start the Garbage Collection (GC) timer, as it only activates when a
route with RTF_EXPIRES is added to a table.

Suggested-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Kui-Feng Lee 2024-02-08 14:06:49 -08:00 committed by David S. Miller
parent 9c52994e32
commit 129e406e18
3 changed files with 7 additions and 3 deletions
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3
include/net/ip6_route.h
View File

@ -170,7 +170,8 @@ struct fib6_info *rt6_get_dflt_router(struct net *net,
struct fib6_info *rt6_add_dflt_router(struct net *net,
const struct in6_addr *gwaddr,
struct net_device *dev, unsigned int pref,
u32 defrtr_usr_metric);
u32 defrtr_usr_metric,
int lifetime);
void rt6_purge_dflt_routers(struct net *net);

3
net/ipv6/ndisc.c
View File

@ -1382,7 +1382,8 @@ static enum skb_drop_reason ndisc_router_discovery(struct sk_buff *skb)
neigh_release(neigh);
rt = rt6_add_dflt_router(net, &ipv6_hdr(skb)->saddr,
skb->dev, pref, defrtr_usr_metric);
skb->dev, pref, defrtr_usr_metric,
lifetime);
if (!rt) {
ND_PRINTK(0, err,
"RA: %s failed to add default route\n",

4
net/ipv6/route.c
View File

@ -4355,7 +4355,8 @@ struct fib6_info *rt6_add_dflt_router(struct net *net,
const struct in6_addr *gwaddr,
struct net_device *dev,
unsigned int pref,
u32 defrtr_usr_metric)
u32 defrtr_usr_metric,
int lifetime)
{
struct fib6_config cfg = {
.fc_table = l3mdev_fib_table(dev) ? : RT6_TABLE_DFLT,
@ -4368,6 +4369,7 @@ struct fib6_info *rt6_add_dflt_router(struct net *net,
.fc_nlinfo.portid = 0,
.fc_nlinfo.nlh = NULL,
.fc_nlinfo.nl_net = net,
.fc_expires = jiffies_to_clock_t(lifetime * HZ),
};
cfg.fc_gateway = *gwaddr;