[IPV6] IP6TUNNEL: Split out generic routine in ip6ip6_xmit().

This enables to add IPv4/IPv6 specific handling later,

Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 98 insertions, 45 deletions

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 985d106dff6d..4546bb923a20 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -678,9 +678,13 @@ static inline int ip6_tnl_xmit_ctl(struct ip6_tnl *t)
         return ret;
 }
 /**
- * ip6ip6_tnl_xmit - encapsulate packet and send
+ * ip6_tnl_xmit2 - encapsulate packet and send
  *   @skb: the outgoing socket buffer
  *   @dev: the outgoing tunnel device
+ *   @dsfield: dscp code for outer header
+ *   @fl: flow of tunneled packet
+ *   @encap_limit: encapsulation limit
+ *   @pmtu: Path MTU is stored if packet is too big
  *
  * Description:
  *   Build new header and do some sanity checks on the packet before sending
@@ -688,62 +692,35 @@ static inline int ip6_tnl_xmit_ctl(struct ip6_tnl *t)
  *
  * Return:
  *   0
+ *   -1 fail
+ *   %-EMSGSIZE message too big. return mtu in this case.
  **/
 
-static int
-ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
+static int ip6_tnl_xmit2(struct sk_buff *skb,
+                         struct net_device *dev,
+                         __u8 dsfield,
+                         struct flowi *fl,
+                         int encap_limit,
+                         __u32 *pmtu)
 {
         struct ip6_tnl *t = netdev_priv(dev);
         struct net_device_stats *stats = &t->stat;
         struct ipv6hdr *ipv6h = skb->nh.ipv6h;
-        int encap_limit = -1;
         struct ipv6_tel_txoption opt;
-        __u16 offset;
-        struct flowi fl;
         struct dst_entry *dst;
         struct net_device *tdev;
         int mtu;
         int max_headroom = sizeof(struct ipv6hdr);
         u8 proto;
-        int err;
+        int err = -1;
         int pkt_len;
-        int dsfield;
-
-        if (t->recursion++) {
-                stats->collisions++;
-                goto tx_err;
-        }
-        if (skb->protocol != htons(ETH_P_IPV6) ||
-            !ip6_tnl_xmit_ctl(t) || ip6ip6_tnl_addr_conflict(t, ipv6h))
-                goto tx_err;
-
-        if ((offset = parse_tlv_tnl_enc_lim(skb, skb->nh.raw)) > 0) {
-                struct ipv6_tlv_tnl_enc_lim *tel;
-                tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->nh.raw[offset];
-                if (tel->encap_limit == 0) {
-                        icmpv6_send(skb, ICMPV6_PARAMPROB,
-                                    ICMPV6_HDR_FIELD, offset + 2, skb->dev);
-                        goto tx_err;
-                }
-                encap_limit = tel->encap_limit - 1;
-        } 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;
-
-        dsfield = ipv6_get_dsfield(ipv6h);
-        if ((t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS))
-                fl.fl6_flowlabel |= (*(__be32 *) ipv6h & IPV6_TCLASS_MASK);
-        if ((t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL))
-                fl.fl6_flowlabel |= (*(__be32 *) ipv6h & IPV6_FLOWLABEL_MASK);
 
         if ((dst = ip6_tnl_dst_check(t)) != NULL)
                 dst_hold(dst);
         else {
-                dst = ip6_route_output(NULL, &fl);
+                dst = ip6_route_output(NULL, fl);
 
-                if (dst->error || xfrm_lookup(&dst, &fl, NULL, 0) < 0)
+                if (dst->error || xfrm_lookup(&dst, fl, NULL, 0) < 0)
                         goto tx_err_link_failure;
         }
 
@@ -767,7 +744,8 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
         if (skb->dst)
                 skb->dst->ops->update_pmtu(skb->dst, mtu);
         if (skb->len > mtu) {
-                icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
+                *pmtu = mtu;
+                err = -EMSGSIZE;
                 goto tx_err_dst_release;
         }
 
@@ -793,20 +771,21 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 
         skb->h.raw = skb->nh.raw;
 
+        proto = fl->proto;
         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);
+        *(__be32*)ipv6h = fl->fl6_flowlabel | htonl(0x60000000);
         dsfield = INET_ECN_encapsulate(0, dsfield);
         ipv6_change_dsfield(ipv6h, ~INET_ECN_MASK, dsfield);
         ipv6h->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
         ipv6h->hop_limit = t->parms.hop_limit;
         ipv6h->nexthdr = proto;
-        ipv6_addr_copy(&ipv6h->saddr, &fl.fl6_src);
-        ipv6_addr_copy(&ipv6h->daddr, &fl.fl6_dst);
+        ipv6_addr_copy(&ipv6h->saddr, &fl->fl6_src);
+        ipv6_addr_copy(&ipv6h->daddr, &fl->fl6_dst);
         nf_reset(skb);
         pkt_len = skb->len;
         err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL,
@@ -820,13 +799,87 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
                 stats->tx_aborted_errors++;
         }
         ip6_tnl_dst_store(t, dst);
-        t->recursion--;
         return 0;
 tx_err_link_failure:
         stats->tx_carrier_errors++;
         dst_link_failure(skb);
 tx_err_dst_release:
         dst_release(dst);
+        return err;
+}
+
+static inline int
+ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+        struct ip6_tnl *t = netdev_priv(dev);
+        struct ipv6hdr *ipv6h = skb->nh.ipv6h;
+        int encap_limit = -1;
+        __u16 offset;
+        struct flowi fl;
+        __u8 dsfield;
+        __u32 mtu;
+        int err;
+
+        if (!ip6_tnl_xmit_ctl(t) || ip6ip6_tnl_addr_conflict(t, ipv6h))
+                return -1;
+
+        if ((offset = parse_tlv_tnl_enc_lim(skb, skb->nh.raw)) > 0) {
+                struct ipv6_tlv_tnl_enc_lim *tel;
+                tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->nh.raw[offset];
+                if (tel->encap_limit == 0) {
+                        icmpv6_send(skb, ICMPV6_PARAMPROB,
+                                    ICMPV6_HDR_FIELD, offset + 2, skb->dev);
+                        return -1;
+                }
+                encap_limit = tel->encap_limit - 1;
+        } else if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
+                encap_limit = t->parms.encap_limit;
+
+        memcpy(&fl, &t->fl, sizeof (fl));
+        fl.proto = IPPROTO_IPV6;
+
+        dsfield = ipv6_get_dsfield(ipv6h);
+        if ((t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS))
+                fl.fl6_flowlabel |= (*(__be32 *) ipv6h & IPV6_TCLASS_MASK);
+        if ((t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL))
+                fl.fl6_flowlabel |= (*(__be32 *) ipv6h & IPV6_FLOWLABEL_MASK);
+
+        err = ip6_tnl_xmit2(skb, dev, dsfield, &fl, encap_limit, &mtu);
+        if (err != 0) {
+                if (err == -EMSGSIZE)
+                        icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
+                return -1;
+        }
+
+        return 0;
+}
+
+static int
+ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+        struct ip6_tnl *t = netdev_priv(dev);
+        struct net_device_stats *stats = &t->stat;
+        int ret;
+
+        if (t->recursion++) {
+                t->stat.collisions++;
+                goto tx_err;
+        }
+
+        switch (skb->protocol) {
+        case __constant_htons(ETH_P_IPV6):
+                ret = ip6ip6_tnl_xmit(skb, dev);
+                break;
+        default:
+                goto tx_err;
+        }
+
+        if (ret < 0)
+                goto tx_err;
+
+        t->recursion--;
+        return 0;
+
 tx_err:
         stats->tx_errors++;
         stats->tx_dropped++;
@@ -1088,7 +1141,7 @@ static void ip6ip6_tnl_dev_setup(struct net_device *dev)
         SET_MODULE_OWNER(dev);
         dev->uninit = ip6ip6_tnl_dev_uninit;
         dev->destructor = free_netdev;
-        dev->hard_start_xmit = ip6ip6_tnl_xmit;
+        dev->hard_start_xmit = ip6_tnl_xmit;
         dev->get_stats = ip6ip6_tnl_get_stats;
         dev->do_ioctl = ip6ip6_tnl_ioctl;
         dev->change_mtu = ip6ip6_tnl_change_mtu;