net: bridge: use mld2r_ngrec instead of icmpv6_dataun

br_ip6_multicast_mld2_report function uses icmp6h
to parse mld2_report packet.

mld2r_ngrec defines mld2r_hdr.icmp6_dataun.un_data16[1]
in include/net/mld.h.

So, it is more compact to use mld2r rather than icmp6h.

By doing printk test, it is confirmed that
icmp6h->icmp6_dataun.un_data16[1] and mld2r->mld2r_ngrec are
indeed equivalent.

Also, sizeof(*mld2r) and sizeof(*icmp6h) are equivalent, too.

Signed-off-by: MichelleJin <shjy180909@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 2c437d4..9231617 100644 (file)
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -2731,8 +2731,8 @@ static int br_ip6_multicast_mld2_report(struct net_bridge_mcast *brmctx,
        struct net_bridge_mdb_entry *mdst;
        struct net_bridge_port_group *pg;
        unsigned int nsrcs_offset;
+       struct mld2_report *mld2r;
        const unsigned char *src;
-       struct icmp6hdr *icmp6h;
        struct in6_addr *h_addr;
        struct mld2_grec *grec;
        unsigned int grec_len;
@@ -2740,12 +2740,12 @@ static int br_ip6_multicast_mld2_report(struct net_bridge_mcast *brmctx,
        int i, len, num;
        int err = 0;
 
-       if (!ipv6_mc_may_pull(skb, sizeof(*icmp6h)))
+       if (!ipv6_mc_may_pull(skb, sizeof(*mld2r)))
                return -EINVAL;
 
-       icmp6h = icmp6_hdr(skb);
-       num = ntohs(icmp6h->icmp6_dataun.un_data16[1]);
-       len = skb_transport_offset(skb) + sizeof(*icmp6h);
+       mld2r = (struct mld2_report *)icmp6_hdr(skb);
+       num = ntohs(mld2r->mld2r_ngrec);
+       len = skb_transport_offset(skb) + sizeof(*mld2r);
 
        for (i = 0; i < num; i++) {
                __be16 *_nsrcs, __nsrcs;