ip6mr: use nla_nest_* helpers

This patch removes the skb manipulations when nested attributes are added by
using standard helpers.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 1c05fe604d37049029b4c8ddfb4c5ef4aa0f4ab6..23f364a9efb5f0304f9202ce5c53797f8d43d103 100644 (file)
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -2119,8 +2119,7 @@ static int __ip6mr_fill_mroute(struct mr6_table *mrt, struct sk_buff *skb,
 {
        int ct;
        struct rtnexthop *nhp;
-       u8 *b = skb_tail_pointer(skb);
-       struct rtattr *mp_head;
+       struct nlattr *mp_attr;
 
        /* If cache is unresolved, don't try to parse IIF and OIF */
        if (c->mf6c_parent >= MAXMIFS)
@@ -2129,28 +2128,29 @@ static int __ip6mr_fill_mroute(struct mr6_table *mrt, struct sk_buff *skb,
        if (MIF_EXISTS(mrt, c->mf6c_parent) &&
            nla_put_u32(skb, RTA_IIF, mrt->vif6_table[c->mf6c_parent].dev->ifindex) < 0)
                return -EMSGSIZE;
-
-       mp_head = (struct rtattr *)skb_put(skb, RTA_LENGTH(0));
+       mp_attr = nla_nest_start(skb, RTA_MULTIPATH);
+       if (mp_attr == NULL)
+               return -EMSGSIZE;
 
        for (ct = c->mfc_un.res.minvif; ct < c->mfc_un.res.maxvif; ct++) {
                if (MIF_EXISTS(mrt, ct) && c->mfc_un.res.ttls[ct] < 255) {
-                       if (skb_tailroom(skb) < RTA_ALIGN(RTA_ALIGN(sizeof(*nhp)) + 4))
-                               goto rtattr_failure;
-                       nhp = (struct rtnexthop *)skb_put(skb, RTA_ALIGN(sizeof(*nhp)));
+                       nhp = nla_reserve_nohdr(skb, sizeof(*nhp));
+                       if (nhp == NULL) {
+                               nla_nest_cancel(skb, mp_attr);
+                               return -EMSGSIZE;
+                       }
+
                        nhp->rtnh_flags = 0;
                        nhp->rtnh_hops = c->mfc_un.res.ttls[ct];
                        nhp->rtnh_ifindex = mrt->vif6_table[ct].dev->ifindex;
                        nhp->rtnh_len = sizeof(*nhp);
                }
        }
-       mp_head->rta_type = RTA_MULTIPATH;
-       mp_head->rta_len = skb_tail_pointer(skb) - (u8 *)mp_head;
+
+       nla_nest_end(skb, mp_attr);
+
        rtm->rtm_type = RTN_MULTICAST;
        return 1;
-
-rtattr_failure:
-       nlmsg_trim(skb, b);
-       return -EMSGSIZE;
 }
 
 int ip6mr_get_route(struct net *net,