[IPV6]: Don't allocate memory for Tunnel Encapsulation Limit Option

Signed-off-by: Ville Nuorvala <vnuorval@tcs.hut.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 36 deletions

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 3944ea24c38..daad1e5a2a8 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -572,31 +572,23 @@ discard:
         return 0;
 }
 
-static inline struct ipv6_txoptions *create_tel(__u8 encap_limit)
-{
-        struct ipv6_tlv_tnl_enc_lim *tel;
-        struct ipv6_txoptions *opt;
-        __u8 *raw;
-
-        int opt_len = sizeof(*opt) + 8;
-
-        if (!(opt = kzalloc(opt_len, GFP_ATOMIC))) {
-                return NULL;
-        }
-        opt->tot_len = opt_len;
-        opt->dst0opt = (struct ipv6_opt_hdr *) (opt + 1);
-        opt->opt_nflen = 8;
+struct ipv6_tel_txoption {
+        struct ipv6_txoptions ops;
+        __u8 dst_opt[8];
+};
 
-        tel = (struct ipv6_tlv_tnl_enc_lim *) (opt->dst0opt + 1);
-        tel->type = IPV6_TLV_TNL_ENCAP_LIMIT;
-        tel->length = 1;
-        tel->encap_limit = encap_limit;
+static void init_tel_txopt(struct ipv6_tel_txoption *opt, __u8 encap_limit)
+{
+        memset(opt, 0, sizeof(struct ipv6_tel_txoption));
 
-        raw = (__u8 *) opt->dst0opt;
-        raw[5] = IPV6_TLV_PADN;
-        raw[6] = 1;
+        opt->dst_opt[2] = IPV6_TLV_TNL_ENCAP_LIMIT;
+        opt->dst_opt[3] = 1;
+        opt->dst_opt[4] = encap_limit;
+        opt->dst_opt[5] = IPV6_TLV_PADN;
+        opt->dst_opt[6] = 1;
 
-        return opt;
+        opt->ops.dst0opt = (struct ipv6_opt_hdr *) opt->dst_opt;
+        opt->ops.opt_nflen = 8;
 }
 
 /**
@@ -666,8 +658,8 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
         struct ip6_tnl *t = netdev_priv(dev);
         struct net_device_stats *stats = &t->stat;
         struct ipv6hdr *ipv6h = skb->nh.ipv6h;
-        struct ipv6_txoptions *opt = NULL;
         int encap_limit = -1;
+        struct ipv6_tel_txoption opt;
         __u16 offset;
         struct flowi fl;
         struct dst_entry *dst;
@@ -696,9 +688,9 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
                         goto tx_err;
                 }
                 encap_limit = tel->encap_limit - 1;
-        } else if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT)) {
+        } else if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
                 encap_limit = t->parms.encap_limit;
-        }
+
         memcpy(&fl, &t->fl, sizeof (fl));
         proto = fl.proto;
 
@@ -708,9 +700,6 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
         if ((t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL))
                 fl.fl6_flowlabel |= (*(__be32 *) ipv6h & IPV6_FLOWLABEL_MASK);
 
-        if (encap_limit >= 0 && (opt = create_tel(encap_limit)) == NULL)
-                goto tx_err;
-
         if ((dst = ip6_tnl_dst_check(t)) != NULL)
                 dst_hold(dst);
         else {
@@ -731,7 +720,7 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
                 goto tx_err_dst_release;
         }
         mtu = dst_mtu(dst) - sizeof (*ipv6h);
-        if (opt) {
+        if (encap_limit >= 0) {
                 max_headroom += 8;
                 mtu -= 8;
         }
@@ -769,9 +758,10 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 
         skb->h.raw = skb->nh.raw;
 
-        if (opt)
-                ipv6_push_nfrag_opts(skb, opt, &proto, NULL);
-
+        if (encap_limit >= 0) {
+                init_tel_txopt(&opt, encap_limit);
+                ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL);
+        }
         skb->nh.raw = skb_push(skb, sizeof(struct ipv6hdr));
         ipv6h = skb->nh.ipv6h;
         *(__be32*)ipv6h = fl.fl6_flowlabel | htonl(0x60000000);
@@ -795,9 +785,6 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
                 stats->tx_aborted_errors++;
         }
         ip6_tnl_dst_store(t, dst);
-
-        kfree(opt);
-
         t->recursion--;
         return 0;
 tx_err_link_failure:
@@ -805,7 +792,6 @@ tx_err_link_failure:
         dst_link_failure(skb);
 tx_err_dst_release:
         dst_release(dst);
-        kfree(opt);
 tx_err:
         stats->tx_errors++;
         stats->tx_dropped++;