ipmr, ip6mr: return lastuse relative to now

When I introduced the lastuse member I made a subtle error because it was
returned as an absolute value but that is meaningless to user-space as it
doesn't allow to see how old exactly an entry is. Let's make it similar to
how the bridge returns such values and make it relative to "now" (jiffies).
This allows us to show the actual age of the entries and is much more
useful (e.g. user-space daemons can age out entries, iproute2 can display
the lastuse properly).

Fixes: 43b9e1274060 ("net: ipmr/ip6mr: add support for keeping an entry age")
Reported-by: Satish Ashok <sashok@cumulusnetworks.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 26253328d227bda8e3a6b23be3130a4ce4231b60..a87bcd2d4a94ed1712dd0379d3f81283a41965d4 100644 (file)
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -2076,6 +2076,7 @@ static int __ipmr_fill_mroute(struct mr_table *mrt, struct sk_buff *skb,
        struct rta_mfc_stats mfcs;
        struct nlattr *mp_attr;
        struct rtnexthop *nhp;
+       unsigned long lastuse;
        int ct;
 
        /* If cache is unresolved, don't try to parse IIF and OIF */
@@ -2105,12 +2106,14 @@ static int __ipmr_fill_mroute(struct mr_table *mrt, struct sk_buff *skb,
 
        nla_nest_end(skb, mp_attr);
 
+       lastuse = READ_ONCE(c->mfc_un.res.lastuse);
+       lastuse = time_after_eq(jiffies, lastuse) ? jiffies - lastuse : 0;
+
        mfcs.mfcs_packets = c->mfc_un.res.pkt;
        mfcs.mfcs_bytes = c->mfc_un.res.bytes;
        mfcs.mfcs_wrong_if = c->mfc_un.res.wrong_if;
        if (nla_put_64bit(skb, RTA_MFC_STATS, sizeof(mfcs), &mfcs, RTA_PAD) ||
-           nla_put_u64_64bit(skb, RTA_EXPIRES,
-                             jiffies_to_clock_t(c->mfc_un.res.lastuse),
+           nla_put_u64_64bit(skb, RTA_EXPIRES, jiffies_to_clock_t(lastuse),
                              RTA_PAD))
                return -EMSGSIZE;
 

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 6122f9c5cc496d2ad329cd4d286c37ddd6239012..fccb5dd91902891a6ef7bb6154b2a5cf6b1c3792 100644 (file)
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -2239,6 +2239,7 @@ static int __ip6mr_fill_mroute(struct mr6_table *mrt, struct sk_buff *skb,
        struct rta_mfc_stats mfcs;
        struct nlattr *mp_attr;
        struct rtnexthop *nhp;
+       unsigned long lastuse;
        int ct;
 
        /* If cache is unresolved, don't try to parse IIF and OIF */
@@ -2269,12 +2270,14 @@ static int __ip6mr_fill_mroute(struct mr6_table *mrt, struct sk_buff *skb,
 
        nla_nest_end(skb, mp_attr);
 
+       lastuse = READ_ONCE(c->mfc_un.res.lastuse);
+       lastuse = time_after_eq(jiffies, lastuse) ? jiffies - lastuse : 0;
+
        mfcs.mfcs_packets = c->mfc_un.res.pkt;
        mfcs.mfcs_bytes = c->mfc_un.res.bytes;
        mfcs.mfcs_wrong_if = c->mfc_un.res.wrong_if;
        if (nla_put_64bit(skb, RTA_MFC_STATS, sizeof(mfcs), &mfcs, RTA_PAD) ||
-           nla_put_u64_64bit(skb, RTA_EXPIRES,
-                             jiffies_to_clock_t(c->mfc_un.res.lastuse),
+           nla_put_u64_64bit(skb, RTA_EXPIRES, jiffies_to_clock_t(lastuse),
                              RTA_PAD))
                return -EMSGSIZE;