ip_tunnels: extend iptunnel_xmit()

Refactor various ip tunnels xmit functions and extend iptunnel_xmit()
so that there is more code sharing.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 108 insertions, 59 deletions

diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index 7fcf8101d85f..86ded0bac9c7 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -11,7 +11,7 @@ obj-y     := route.o inetpeer.o protocol.o \
              tcp_offload.o datagram.o raw.o udp.o udplite.o \
              udp_offload.o arp.o icmp.o devinet.o af_inet.o igmp.o \
              fib_frontend.o fib_semantics.o fib_trie.o \
-             inet_fragment.o ping.o
+             inet_fragment.o ping.o ip_tunnel_core.o
 
 obj-$(CONFIG_NET_IP_TUNNEL) += ip_tunnel.o
 obj-$(CONFIG_SYSCTL) += sysctl_net_ipv4.o
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index e189db409b0e..a06a2ed49597 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -491,19 +491,17 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
 {
         struct ip_tunnel *tunnel = netdev_priv(dev);
         const struct iphdr *inner_iph;
-        struct iphdr *iph;
         struct flowi4 fl4;
         u8     tos, ttl;
         __be16 df;
         struct rtable *rt;              /* Route to the other host */
-        struct net_device *tdev;        /* Device to other host */
         unsigned int max_headroom;      /* The extra header space needed */
         __be32 dst;
         int mtu;
+        int err;
 
         inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
 
-        memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
         dst = tnl_params->daddr;
         if (dst == 0) {
                 /* NBMA tunnel */
@@ -571,14 +569,11 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
                 dev->stats.tx_carrier_errors++;
                 goto tx_error;
         }
-        tdev = rt->dst.dev;
-
-        if (tdev == dev) {
+        if (rt->dst.dev == dev) {
                 ip_rt_put(rt);
                 dev->stats.collisions++;
                 goto tx_error;
         }
-
         df = tnl_params->frag_off;
 
         if (df)
@@ -596,6 +591,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
                 if (!skb_is_gso(skb) &&
                     (inner_iph->frag_off&htons(IP_DF)) &&
                      mtu < ntohs(inner_iph->tot_len)) {
+                        memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
                         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
                         ip_rt_put(rt);
                         goto tx_error;
@@ -646,8 +642,8 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
                         ttl = ip4_dst_hoplimit(&rt->dst);
         }
 
-        max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct iphdr)
-                                               + rt->dst.header_len;
+        max_headroom = LL_RESERVED_SPACE(rt->dst.dev) + sizeof(struct iphdr)
+                        + rt->dst.header_len;
         if (max_headroom > dev->needed_headroom) {
                 dev->needed_headroom = max_headroom;
                 if (skb_cow_head(skb, dev->needed_headroom)) {
@@ -657,27 +653,11 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
                 }
         }
 
-        skb_dst_drop(skb);
-        skb_dst_set(skb, &rt->dst);
-
-        /* Push down and install the IP header. */
-        skb_push(skb, sizeof(struct iphdr));
-        skb_reset_network_header(skb);
-
-        iph = ip_hdr(skb);
-        inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
+        err = iptunnel_xmit(dev_net(dev), rt, skb,
+                            fl4.saddr, fl4.daddr, protocol,
+                            ip_tunnel_ecn_encap(tos, inner_iph, skb), ttl, df);
+        iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
 
-        iph->version    =       4;
-        iph->ihl        =       sizeof(struct iphdr) >> 2;
-        iph->frag_off   =       df;
-        iph->protocol   =       protocol;
-        iph->tos        =       ip_tunnel_ecn_encap(tos, inner_iph, skb);
-        iph->daddr      =       fl4.daddr;
-        iph->saddr      =       fl4.saddr;
-        iph->ttl        =       ttl;
-        tunnel_ip_select_ident(skb, inner_iph, &rt->dst);
-
-        iptunnel_xmit(skb, dev);
         return;
 
 #if IS_ENABLED(CONFIG_IPV6)
diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
new file mode 100644
index 000000000000..927687e83f18
--- /dev/null
+++ b/net/ipv4/ip_tunnel_core.c
@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2013 Nicira, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/in.h>
+#include <linux/if_arp.h>
+#include <linux/mroute.h>
+#include <linux/init.h>
+#include <linux/in6.h>
+#include <linux/inetdevice.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/etherdevice.h>
+#include <linux/if_ether.h>
+#include <linux/if_vlan.h>
+
+#include <net/ip.h>
+#include <net/icmp.h>
+#include <net/protocol.h>
+#include <net/ip_tunnels.h>
+#include <net/arp.h>
+#include <net/checksum.h>
+#include <net/dsfield.h>
+#include <net/inet_ecn.h>
+#include <net/xfrm.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+#include <net/rtnetlink.h>
+
+int iptunnel_xmit(struct net *net, struct rtable *rt,
+                  struct sk_buff *skb,
+                  __be32 src, __be32 dst, __u8 proto,
+                  __u8 tos, __u8 ttl, __be16 df)
+{
+        int pkt_len = skb->len;
+        struct iphdr *iph;
+        int err;
+
+        nf_reset(skb);
+        secpath_reset(skb);
+        skb->rxhash = 0;
+        skb_dst_drop(skb);
+        skb_dst_set(skb, &rt->dst);
+        memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
+
+        /* Push down and install the IP header. */
+        __skb_push(skb, sizeof(struct iphdr));
+        skb_reset_network_header(skb);
+
+        iph = ip_hdr(skb);
+
+        iph->version    =       4;
+        iph->ihl        =       sizeof(struct iphdr) >> 2;
+        iph->frag_off   =       df;
+        iph->protocol   =       proto;
+        iph->tos        =       tos;
+        iph->daddr      =       dst;
+        iph->saddr      =       src;
+        iph->ttl        =       ttl;
+        tunnel_ip_select_ident(skb,
+                               (const struct iphdr *)skb_inner_network_header(skb),
+                               &rt->dst);
+
+        err = ip_local_out(skb);
+        if (unlikely(net_xmit_eval(err)))
+                pkt_len = 0;
+        return pkt_len;
+}
+EXPORT_SYMBOL_GPL(iptunnel_xmit);
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 6b9c1f128eaf..76bb8de435b2 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -723,13 +723,14 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
         __be16 df = tiph->frag_off;
         struct rtable *rt;                      /* Route to the other host */
         struct net_device *tdev;                /* Device to other host */
-        struct iphdr  *iph;                     /* Our new IP header */
         unsigned int max_headroom;              /* The extra header space needed */
         __be32 dst = tiph->daddr;
         struct flowi4 fl4;
         int    mtu;
         const struct in6_addr *addr6;
         int addr_type;
+        u8 ttl;
+        int err;
 
         if (skb->protocol != htons(ETH_P_IPV6))
                 goto tx_error;
@@ -872,34 +873,14 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
                 skb = new_skb;
                 iph6 = ipv6_hdr(skb);
         }
-
-        skb->transport_header = skb->network_header;
-        skb_push(skb, sizeof(struct iphdr));
-        skb_reset_network_header(skb);
-        memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
-        IPCB(skb)->flags = 0;
-        skb_dst_drop(skb);
-        skb_dst_set(skb, &rt->dst);
-
-        /*
-         *      Push down and install the IPIP header.
-         */
-
-        iph                     =       ip_hdr(skb);
-        iph->version            =       4;
-        iph->ihl                =       sizeof(struct iphdr)>>2;
-        iph->frag_off           =       df;
-        iph->protocol           =       IPPROTO_IPV6;
-        iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
-        iph->daddr              =       fl4.daddr;
-        iph->saddr              =       fl4.saddr;
-
-        if ((iph->ttl = tiph->ttl) == 0)
-                iph->ttl        =       iph6->hop_limit;
-
-        skb->ip_summed = CHECKSUM_NONE;
-        ip_select_ident(iph, skb_dst(skb), NULL);
-        iptunnel_xmit(skb, dev);
+        ttl = tiph->ttl;
+        if (ttl == 0)
+                ttl = iph6->hop_limit;
+        tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
+
+        err = iptunnel_xmit(dev_net(dev), rt, skb, fl4.saddr, fl4.daddr,
+                            IPPROTO_IPV6, tos, ttl, df);
+        iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
         return NETDEV_TX_OK;
 
 tx_error_icmp: