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>

1 files changed, 13 insertions, 13 deletions

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 1c05fe604d37..23f364a9efb5 100644
--- 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,