net: ipv6: mld: get rid of MLDV2_MRC and simplify calculation

Get rid of MLDV2_MRC and use our new macros for mantisse and
exponent to calculate Maximum Response Delay out of the Maximum
Response Code.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 23 insertions, 26 deletions

diff --git a/include/net/mld.h b/include/net/mld.h
index 2b5421f6a7c2..faa1d161bf24 100644
--- a/include/net/mld.h
+++ b/include/net/mld.h
@@ -63,15 +63,6 @@ struct mld2_query {
 #define mld2q_mrc               mld2q_hdr.icmp6_maxdelay
 #define mld2q_resv1             mld2q_hdr.icmp6_dataun.un_data16[1]
 
-/* Max Response Code, TODO: transform this to use the below */
-#define MLDV2_MASK(value, nb) ((nb)>=32 ? (value) : ((1<<(nb))-1) & (value))
-#define MLDV2_EXP(thresh, nbmant, nbexp, value) \
-        ((value) < (thresh) ? (value) : \
-        ((MLDV2_MASK(value, nbmant) | (1<<(nbmant))) << \
-        (MLDV2_MASK((value) >> (nbmant), nbexp) + (nbexp))))
-
-#define MLDV2_MRC(value) MLDV2_EXP(0x8000, 12, 3, value)
-
 /* RFC3810, 5.1.3. Maximum Response Code:
  *
  * If Maximum Response Code >= 32768, Maximum Response Code represents a
@@ -97,4 +88,23 @@ struct mld2_query {
 #define MLDV2_QQIC_EXP(value)   (((value) >> 4) & 0x07)
 #define MLDV2_QQIC_MAN(value)   ((value) & 0x0f)
 
+static inline unsigned long mldv2_mrc(const struct mld2_query *mlh2)
+{
+        /* RFC3810, 5.1.3. Maximum Response Code */
+        unsigned long ret, mc_mrc = ntohs(mlh2->mld2q_mrc);
+
+        if (mc_mrc < 32768) {
+                ret = mc_mrc;
+        } else {
+                unsigned long mc_man, mc_exp;
+
+                mc_exp = MLDV2_MRC_EXP(mc_mrc);
+                mc_man = MLDV2_MRC_MAN(mc_mrc);
+
+                ret = (mc_man | 0x1000) << (mc_exp + 3);
+        }
+
+        return ret;
+}
+
 #endif
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 08e576ada0b2..4accd0de6e8e 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1203,7 +1203,8 @@ static int br_ip6_multicast_query(struct net_bridge *br,
                 mld2q = (struct mld2_query *)icmp6_hdr(skb);
                 if (!mld2q->mld2q_nsrcs)
                         group = &mld2q->mld2q_mca;
-                max_delay = mld2q->mld2q_mrc ? MLDV2_MRC(ntohs(mld2q->mld2q_mrc)) : 1;
+
+                max_delay = max(msecs_to_jiffies(mldv2_mrc(mld2q)), 1UL);
         }
 
         br_multicast_query_received(br, port, !ipv6_addr_any(&ip6h->saddr),
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index f86e26b7296c..005b22fd6bcb 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -1195,20 +1195,7 @@ static void mld_update_qri(struct inet6_dev *idev,
          *  - 5.1.3. Maximum Response Code
          *  - 9.3. Query Response Interval
          */
-        unsigned long mc_qri, mc_mrc = ntohs(mlh2->mld2q_mrc);
-
-        if (mc_mrc < 32768) {
-                mc_qri = mc_mrc;
-        } else {
-                unsigned long mc_man, mc_exp;
-
-                mc_exp = MLDV2_MRC_EXP(mc_mrc);
-                mc_man = MLDV2_MRC_MAN(mc_mrc);
-
-                mc_qri = (mc_man | 0x1000) << (mc_exp + 3);
-        }
-
-        idev->mc_qri = msecs_to_jiffies(mc_qri);
+        idev->mc_qri = msecs_to_jiffies(mldv2_mrc(mlh2));
 }
 
 /* called with rcu_read_lock() */
@@ -1277,8 +1264,7 @@ int igmp6_event_query(struct sk_buff *skb)
 
                 mlh2 = (struct mld2_query *)skb_transport_header(skb);
 
-                max_delay = max(msecs_to_jiffies(MLDV2_MRC(ntohs(mlh2->mld2q_mrc))), 1UL);
-
+                max_delay = max(msecs_to_jiffies(mldv2_mrc(mlh2)), 1UL);
                 idev->mc_maxdelay = max_delay;
 
                 mld_update_qrv(idev, mlh2);