[net-next,02/02] net/ipv4: VTI support new module for ip_vti.

New VTI tunnel kernel module, Kconfig and Makefile changes.

Signed-off-by: Saurabh Mohan <saurabh.mohan@vyatta.com>
Reviewed-by: Stephen Hemminger <shemminger@vyatta.com>

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On Fri, Jun 08, 2012 at 10:32:53AM -0700, Saurabh wrote:
> 
> 
> New VTI tunnel kernel module, Kconfig and Makefile changes.

It is an interesting feature, do you plan for an IPv6
version too?

I made some comments on the code below.

Thanks.

> 
> Signed-off-by: Saurabh Mohan <saurabh.mohan@vyatta.com>
> Reviewed-by: Stephen Hemminger <shemminger@vyatta.com>
> 
> ---
> diff --git a/include/linux/if_tunnel.h b/include/linux/if_tunnel.h
> index 16b92d0..4b4ce17 100644
> --- a/include/linux/if_tunnel.h
> +++ b/include/linux/if_tunnel.h
> @@ -80,4 +80,15 @@ enum {
>  
>  #define IFLA_GRE_MAX	(__IFLA_GRE_MAX - 1)
>  
> +enum {
> +	IFLA_VTI_UNSPEC,
> +	IFLA_VTI_LINK,
> +	IFLA_VTI_IKEY,
> +	IFLA_VTI_OKEY,
> +	IFLA_VTI_LOCAL,
> +	IFLA_VTI_REMOTE,
> +	__IFLA_VTI_MAX,
> +};
> +
> +#define IFLA_VTI_MAX	(__IFLA_VTI_MAX - 1)
>  #endif /* _IF_TUNNEL_H_ */
> diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
> index 20f1cb5..3a95308 100644
> --- a/net/ipv4/Kconfig
> +++ b/net/ipv4/Kconfig
> @@ -310,6 +310,20 @@ config SYN_COOKIES
>  
>  	  If unsure, say N.
>  
> +config NET_IPVTI
> +    tristate "Virtual (secure) IP: tunneling"
> +    select INET_TUNNEL

You added your register/deregister functions to net/ipv4/xfrm4_mode_tunnel.c,
so this should somehow select or depend on INET_XFRM_MODE_TUNNEL.

> +    ---help---
> +      Tunneling means encapsulating data of one protocol type within
> +      another protocol and sending it over a channel that understands the
> +      Pencapsulating protocol. This particular tunneling driver implements
> +      encapsulation of IP within IP-ESP. This can be used with xfrm to give
> +      the notion of a secure tunnel and then use routing protocol on top.
> +
> +      Saying Y to this option will produce one module ( = code which can
> +      be inserted in and removed from the running kernel whenever you
> +      want). Most people won't need this and can say N.
> +
>  config INET_AH
>  	tristate "IP: AH transformation"
>  	select XFRM_ALGO
> diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
> index ff75d3b..3999ce9 100644
> --- a/net/ipv4/Makefile
> +++ b/net/ipv4/Makefile
> @@ -20,6 +20,7 @@ obj-$(CONFIG_IP_MROUTE) += ipmr.o
>  obj-$(CONFIG_NET_IPIP) += ipip.o
>  obj-$(CONFIG_NET_IPGRE_DEMUX) += gre.o
>  obj-$(CONFIG_NET_IPGRE) += ip_gre.o
> +obj-$(CONFIG_NET_IPVTI) += ip_vti.o
>  obj-$(CONFIG_SYN_COOKIES) += syncookies.o
>  obj-$(CONFIG_INET_AH) += ah4.o
>  obj-$(CONFIG_INET_ESP) += esp4.o
> diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
> new file mode 100644
> index 0000000..3eaa47c
> --- /dev/null
> +++ b/net/ipv4/ip_vti.c
> @@ -0,0 +1,980 @@
> +/*
> + *	Linux NET3:	IP/IP protocol decoder modified to support virtual tunnel interface
> + *
> + *	Authors:
> + *		Sam Lantinga (slouken@cs.ucdavis.edu)  02/01/95
> + *		Saurabh Mohan (saurabh.mohan@vyatta.com) 05/07/2012
> + *
> + *	This program is free software; you can redistribute it and/or
> + *	modify it under the terms of the GNU General Public License
> + *	as published by the Free Software Foundation; either version
> + *	2 of the License, or (at your option) any later version.
> + *
> + */
> +
> +/*
> +   This version of net/ipv4/ip_vti.c is cloned of net/ipv4/ipip.c
> +
> +   For comments look at net/ipv4/ip_gre.c --ANK
> + */
> +
> +
> +#include <linux/capability.h>
> +#include <linux/module.h>
> +#include <linux/types.h>
> +#include <linux/kernel.h>
> +#include <linux/uaccess.h>
> +#include <linux/skbuff.h>
> +#include <linux/netdevice.h>
> +#include <linux/in.h>
> +#include <linux/tcp.h>
> +#include <linux/udp.h>
> +#include <linux/if_arp.h>
> +#include <linux/mroute.h>
> +#include <linux/init.h>
> +#include <linux/netfilter_ipv4.h>
> +#include <linux/if_ether.h>
> +
> +#include <net/sock.h>
> +#include <net/ip.h>
> +#include <net/icmp.h>
> +#include <net/ipip.h>
> +#include <net/inet_ecn.h>
> +#include <net/xfrm.h>
> +#include <net/net_namespace.h>
> +#include <net/netns/generic.h>
> +
> +#define HASH_SIZE  16
> +#define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
> +
> +static struct rtnl_link_ops vti_link_ops __read_mostly;
> +
> +static int vti_net_id __read_mostly;
> +struct vti_net {
> +	struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
> +	struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
> +	struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
> +	struct ip_tunnel __rcu *tunnels_wc[1];
> +	struct ip_tunnel **tunnels[4];
> +
> +	struct net_device *fb_tunnel_dev;
> +};
> +
> +static int vti_fb_tunnel_init(struct net_device *dev);
> +static int vti_tunnel_init(struct net_device *dev);
> +static void vti_tunnel_setup(struct net_device *dev);
> +static void vti_dev_free(struct net_device *dev);
> +static int vti_tunnel_bind_dev(struct net_device *dev);
> +
> +/*
> + * Locking : hash tables are protected by RCU and RTNL
> + */
> +
> +#define for_each_ip_tunnel_rcu(start) \
> +	for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
> +
> +/* often modified stats are per cpu, other are shared (netdev->stats) */
> +struct pcpu_tstats {
> +	u64	rx_packets;
> +	u64	rx_bytes;
> +	u64	tx_packets;
> +	u64	tx_bytes;
> +	struct	u64_stats_sync	syncp;
> +};
> +
> +#define VTI_XMIT(stats1, stats2) do {				\
> +	int err;						\
> +	int pkt_len = skb->len;					\
> +	err = dst_output(skb);					\
> +	if (net_xmit_eval(err) == 0) {				\
> +		(stats1)->tx_bytes += pkt_len;			\
> +		(stats1)->tx_packets++;				\
> +	} else {						\
> +		(stats2)->tx_errors++;				\
> +		(stats2)->tx_aborted_errors++;			\
> +	}							\
> +} while (0)
> +
> +
> +static struct rtnl_link_stats64 *vti_get_stats64(struct net_device *dev,
> +					       struct rtnl_link_stats64 *tot)
> +{
> +	int i;
> +
> +	for_each_possible_cpu(i) {
> +		const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);
> +		u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
> +		unsigned int start;
> +
> +		do {
> +			start = u64_stats_fetch_begin_bh(&tstats->syncp);
> +			rx_packets = tstats->rx_packets;
> +			tx_packets = tstats->tx_packets;
> +			rx_bytes = tstats->rx_bytes;
> +			tx_bytes = tstats->tx_bytes;
> +		} while (u64_stats_fetch_retry_bh(&tstats->syncp, start));
> +
> +		tot->rx_packets += rx_packets;
> +		tot->tx_packets += tx_packets;
> +		tot->rx_bytes   += rx_bytes;
> +		tot->tx_bytes   += tx_bytes;
> +	}
> +
> +	tot->multicast = dev->stats.multicast;
> +	tot->rx_crc_errors = dev->stats.rx_crc_errors;
> +	tot->rx_fifo_errors = dev->stats.rx_fifo_errors;
> +	tot->rx_length_errors = dev->stats.rx_length_errors;
> +	tot->rx_errors = dev->stats.rx_errors;
> +	tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
> +	tot->tx_carrier_errors = dev->stats.tx_carrier_errors;
> +	tot->tx_dropped = dev->stats.tx_dropped;
> +	tot->tx_aborted_errors = dev->stats.tx_aborted_errors;
> +	tot->tx_errors = dev->stats.tx_errors;
> +
> +	return tot;
> +}
> +
> +static struct ip_tunnel *vti_tunnel_lookup(struct net *net,
> +					 __be32 remote, __be32 local)
> +{
> +	unsigned h0 = HASH(remote);
> +	unsigned h1 = HASH(local);
> +	struct ip_tunnel *t;
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +
> +	for_each_ip_tunnel_rcu(ipn->tunnels_r_l[h0 ^ h1])
> +		if (local == t->parms.iph.saddr &&
> +		    remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
> +			return t;
> +	for_each_ip_tunnel_rcu(ipn->tunnels_r[h0])
> +		if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
> +			return t;
> +
> +	for_each_ip_tunnel_rcu(ipn->tunnels_l[h1])
> +		if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
> +			return t;
> +
> +	for_each_ip_tunnel_rcu(ipn->tunnels_wc[0])
> +		if (t && (t->dev->flags&IFF_UP))
> +			return t;
> +	return NULL;
> +}
> +
> +static struct ip_tunnel **__vti_bucket(struct vti_net *ipn,
> +				     struct ip_tunnel_parm *parms)
> +{
> +	__be32 remote = parms->iph.daddr;
> +	__be32 local = parms->iph.saddr;
> +	unsigned h = 0;
> +	int prio = 0;
> +
> +	if (remote) {
> +		prio |= 2;
> +		h ^= HASH(remote);
> +	}
> +	if (local) {
> +		prio |= 1;
> +		h ^= HASH(local);
> +	}
> +	return &ipn->tunnels[prio][h];
> +}
> +
> +static inline struct ip_tunnel **vti_bucket(struct vti_net *ipn,
> +					  struct ip_tunnel *t)
> +{
> +	return __vti_bucket(ipn, &t->parms);
> +}
> +
> +static void vti_tunnel_unlink(struct vti_net *ipn, struct ip_tunnel *t)
> +{
> +	struct ip_tunnel __rcu **tp;
> +	struct ip_tunnel *iter;
> +
> +	for (tp = vti_bucket(ipn, t);
> +	     (iter = rtnl_dereference(*tp)) != NULL;
> +	     tp = &iter->next) {
> +		if (t == iter) {
> +			rcu_assign_pointer(*tp, t->next);
> +			break;
> +		}
> +	}
> +}
> +
> +static void vti_tunnel_link(struct vti_net *ipn, struct ip_tunnel *t)
> +{
> +	struct ip_tunnel __rcu **tp = vti_bucket(ipn, t);
> +
> +	rcu_assign_pointer(t->next, rtnl_dereference(*tp));
> +	rcu_assign_pointer(*tp, t);
> +}
> +
> +static struct ip_tunnel *vti_tunnel_locate(struct net *net,
> +					 struct ip_tunnel_parm *parms,
> +					 int create)
> +{
> +	__be32 remote = parms->iph.daddr;
> +	__be32 local = parms->iph.saddr;
> +	struct ip_tunnel *t, *nt;
> +	struct ip_tunnel __rcu **tp;
> +	struct net_device *dev;
> +	char name[IFNAMSIZ];
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +
> +	for (tp = __vti_bucket(ipn, parms);
> +	     (t = rtnl_dereference(*tp)) != NULL;
> +	     tp = &t->next) {
> +		if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
> +			return t;
> +	}
> +	if (!create)
> +		return NULL;
> +
> +	if (parms->name[0])
> +		strlcpy(name, parms->name, IFNAMSIZ);
> +	else
> +		strcpy(name, "vti%d");
> +
> +	dev = alloc_netdev(sizeof(*t), name, vti_tunnel_setup);
> +	if (dev == NULL)
> +		return NULL;
> +
> +	dev_net_set(dev, net);
> +
> +	nt = netdev_priv(dev);
> +	nt->parms = *parms;
> +	dev->rtnl_link_ops = &vti_link_ops;
> +
> +	vti_tunnel_bind_dev(dev);
> +
> +	if (register_netdevice(dev) < 0)
> +		goto failed_free;
> +
> +	dev_hold(dev);
> +	vti_tunnel_link(ipn, nt);
> +	return nt;
> +
> + failed_free:
> +	free_netdev(dev);
> +	return NULL;
> +}
> +
> +static void vti_tunnel_uninit(struct net_device *dev)
> +{
> +	struct net *net = dev_net(dev);
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +
> +	if (dev == ipn->fb_tunnel_dev)
> +		RCU_INIT_POINTER(ipn->tunnels_wc[0], NULL);
> +	else
> +		vti_tunnel_unlink(ipn, netdev_priv(dev));
> +	dev_put(dev);
> +}
> +
> +static int vti_err(struct sk_buff *skb, u32 info)
> +{
> +
> +	/* All the routers (except for Linux) return only
> +	 * 8 bytes of packet payload. It means, that precise relaying of
> +	 * ICMP in the real Internet is absolutely infeasible.
> +	 */
> +	struct iphdr *iph = (struct iphdr *)skb->data;
> +	const int type = icmp_hdr(skb)->type;
> +	const int code = icmp_hdr(skb)->code;
> +	struct ip_tunnel *t;
> +	int err;
> +
> +	switch (type) {
> +	default:
> +	case ICMP_PARAMETERPROB:
> +		return 0;
> +
> +	case ICMP_DEST_UNREACH:
> +		switch (code) {
> +		case ICMP_SR_FAILED:
> +		case ICMP_PORT_UNREACH:
> +			/* Impossible event. */
> +			return 0;
> +		case ICMP_FRAG_NEEDED:
> +			/* Soft state for pmtu is maintained by IP core. */
> +			return 0;
> +		default:
> +			/* All others are translated to HOST_UNREACH. */
> +			break;
> +		}
> +		break;
> +	case ICMP_TIME_EXCEEDED:
> +		if (code != ICMP_EXC_TTL)
> +			return 0;
> +		break;
> +	}
> +
> +	err = -ENOENT;
> +
> +	rcu_read_lock();
> +	t = vti_tunnel_lookup(dev_net(skb->dev), iph->daddr, iph->saddr);
> +	if (t == NULL || t->parms.iph.daddr == 0)
> +		goto out;
> +
> +	err = 0;
> +	if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
> +		goto out;
> +
> +	if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
> +		t->err_count++;
> +	else
> +		t->err_count = 1;
> +	t->err_time = jiffies;
> +out:
> +	rcu_read_unlock();
> +	return err;
> +}
> +
> +static inline void vti_ecn_decapsulate(const struct iphdr *outer_iph,
> +					struct sk_buff *skb)
> +{
> +	struct iphdr *inner_iph = ip_hdr(skb);
> +
> +	if (INET_ECN_is_ce(outer_iph->tos))
> +		IP_ECN_set_ce(inner_iph);
> +}

vti_ecn_decapsulate is unused.

> +
> +/*
> + * We dont digest the packet therefore let the packet pass.
> + */
> +static int vti_rcv(struct sk_buff *skb)
> +{
> +	struct ip_tunnel *tunnel;
> +	const struct iphdr *iph = ip_hdr(skb);
> +
> +	rcu_read_lock();
> +	tunnel = vti_tunnel_lookup(dev_net(skb->dev), iph->saddr, iph->daddr);
> +	if (tunnel != NULL) {
> +		struct pcpu_tstats *tstats;
> +
> +		tstats = this_cpu_ptr(tunnel->dev->tstats);
> +		tstats->rx_packets++;
> +		tstats->rx_bytes += skb->len;
> +
> +		skb->dev = tunnel->dev;
> +		skb_dst_drop(skb);

Really need to drop a refcount here? xfrm_input() does that too before
it reinjects the packet into layer 2.

> +		nf_reset(skb);

Same here.

> +		rcu_read_unlock();
> +		/* We do not eat the packet here therefore return 1 */
> +		return 1;
> +	}
> +	rcu_read_unlock();
> +
> +	return -1;
> +}
> +
> +/*
> + *	This function assumes it is being called from dev_queue_xmit()
> + *	and that skb is filled properly by that function.
> + */
> +
> +static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
> +{
> +	struct ip_tunnel *tunnel = netdev_priv(dev);
> +	struct pcpu_tstats *tstats;
> +	struct net_device_stats *stats = &tunnel->dev->stats;
> +	struct iphdr  *tiph = &tunnel->parms.iph;
> +	u8     tos = tunnel->parms.iph.tos;
> +	struct rtable *rt;		/* Route to the other host */
> +	struct net_device *tdev;	/* Device to other host */
> +	struct iphdr  *old_iph = ip_hdr(skb);
> +	__be32 dst = tiph->daddr;
> +	struct flowi4 fl4;
> +
> +	if (skb->protocol != htons(ETH_P_IP))
> +		goto tx_error;
> +
> +	if (tos&1)
> +		tos = old_iph->tos;
> +
> +	if (!dst) {
> +		/* NBMA tunnel */
> +		rt = skb_rtable(skb);
> +		if (rt == NULL) {
> +			stats->tx_fifo_errors++;
> +			goto tx_error;
> +		}
> +		dst = rt->rt_gateway;
> +		if (dst == 0)
> +			goto tx_error_icmp;
> +	}
> +
> +	memset(&fl4, 0, sizeof(fl4));
> +	flowi4_init_output(&fl4, tunnel->parms.link,
> +		htonl(tunnel->parms.i_key), RT_TOS(tos), RT_SCOPE_UNIVERSE,
> +		IPPROTO_IPIP, 0,
> +		dst, tiph->saddr, 0, 0);
> +	rt = ip_route_output_key(dev_net(dev), &fl4);
> +	if (IS_ERR(rt)) {
> +		dev->stats.tx_carrier_errors++;
> +		goto tx_error_icmp;
> +	}
> +#ifdef CONFIG_XFRM
> +		/* if there is no transform then this tunnel is not functional. */
> +		if (!rt->dst.xfrm) {
> +			stats->tx_carrier_errors++;
> +			goto tx_error_icmp;
> +		}
> +#endif
> +	tdev = rt->dst.dev;
> +
> +	if (tdev == dev) {
> +		ip_rt_put(rt);
> +		stats->collisions++;
> +		goto tx_error;
> +
> +	}
> +
> +
> +	if (tunnel->err_count > 0) {
> +		if (time_before(jiffies,
> +				tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
> +			tunnel->err_count--;
> +			dst_link_failure(skb);
> +		} else
> +			tunnel->err_count = 0;
> +	}
> +
> +
> +	IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
> +			      IPSKB_REROUTED);
> +	skb_dst_drop(skb);
> +	skb_dst_set(skb, &rt->dst);
> +	nf_reset(skb);
> +	skb->dev = skb_dst(skb)->dev;
> +
> +	tstats = this_cpu_ptr(dev->tstats);
> +	VTI_XMIT(tstats, &dev->stats);
> +	return NETDEV_TX_OK;
> +
> +tx_error_icmp:
> +	dst_link_failure(skb);
> +tx_error:
> +	stats->tx_errors++;
> +	dev_kfree_skb(skb);
> +	return NETDEV_TX_OK;
> +}
> +
> +static int vti_tunnel_bind_dev(struct net_device *dev)
> +{
> +	struct net_device *tdev = NULL;
> +	struct ip_tunnel *tunnel;
> +	struct iphdr *iph;
> +
> +	tunnel = netdev_priv(dev);
> +	iph = &tunnel->parms.iph;
> +
> +	if (iph->daddr) {
> +		struct rtable *rt;
> +		struct flowi4 fl4;
> +		memset(&fl4, 0, sizeof(fl4));
> +		flowi4_init_output(&fl4, tunnel->parms.link,
> +				htonl(tunnel->parms.i_key), RT_TOS(iph->tos), RT_SCOPE_UNIVERSE,
> +				IPPROTO_IPIP, 0,
> +				iph->daddr, iph->saddr, 0, 0);
> +		rt = ip_route_output_key(dev_net(dev), &fl4);
> +		if (!IS_ERR(rt)) {
> +			tdev = rt->dst.dev;
> +			ip_rt_put(rt);
> +		}
> +		dev->flags |= IFF_POINTOPOINT;
> +	}
> +
> +	if (!tdev && tunnel->parms.link)
> +		tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
> +
> +	if (tdev) {
> +		dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
> +		dev->mtu = tdev->mtu;
> +	}
> +	dev->iflink = tunnel->parms.link;
> +	return dev->mtu;
> +}
> +
> +static int
> +vti_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
> +{
> +	int err = 0;
> +	struct ip_tunnel_parm p;
> +	struct ip_tunnel *t;
> +	struct net *net = dev_net(dev);
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +
> +	switch (cmd) {
> +	case SIOCGETTUNNEL:
> +		t = NULL;
> +		if (dev == ipn->fb_tunnel_dev) {
> +			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
> +				err = -EFAULT;
> +				break;
> +			}
> +			t = vti_tunnel_locate(net, &p, 0);
> +		}
> +		if (t == NULL)
> +			t = netdev_priv(dev);
> +		memcpy(&p, &t->parms, sizeof(p));
> +		p.i_flags |= GRE_KEY;
> +		p.o_flags |= GRE_KEY;
> +		if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
> +			err = -EFAULT;
> +		break;
> +
> +	case SIOCADDTUNNEL:
> +	case SIOCCHGTUNNEL:
> +		err = -EPERM;
> +		if (!capable(CAP_NET_ADMIN))
> +			goto done;
> +
> +		err = -EFAULT;
> +		if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
> +			goto done;
> +
> +		err = -EINVAL;
> +		if (p.iph.version != 4 || p.iph.protocol != IPPROTO_ESP ||
> +		    p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
> +			goto done;
> +		if (p.iph.ttl)
> +			p.iph.frag_off |= htons(IP_DF);
> +
> +		t = vti_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
> +
> +		if (dev != ipn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
> +			if (t != NULL) {
> +				if (t->dev != dev) {
> +					err = -EEXIST;
> +					break;
> +				}
> +			} else {
> +				if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
> +				    (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
> +					err = -EINVAL;
> +					break;
> +				}
> +				t = netdev_priv(dev);
> +				vti_tunnel_unlink(ipn, t);
> +				synchronize_net();
> +				t->parms.iph.saddr = p.iph.saddr;
> +				t->parms.iph.daddr = p.iph.daddr;
> +				t->parms.i_key = p.i_key;
> +				t->parms.o_key = p.o_key;
> +				t->parms.iph.protocol = IPPROTO_ESP;
> +				memcpy(dev->dev_addr, &p.iph.saddr, 4);
> +				memcpy(dev->broadcast, &p.iph.daddr, 4);
> +				vti_tunnel_link(ipn, t);
> +				netdev_state_change(dev);
> +			}
> +		}
> +
> +		if (t) {
> +			err = 0;
> +			if (cmd == SIOCCHGTUNNEL) {
> +				t->parms.iph.ttl = p.iph.ttl;
> +				t->parms.iph.tos = p.iph.tos;
> +				t->parms.iph.frag_off = p.iph.frag_off;
> +				t->parms.i_key = p.i_key;
> +				t->parms.o_key = p.o_key;
> +				if (t->parms.link != p.link) {
> +					t->parms.link = p.link;
> +					vti_tunnel_bind_dev(dev);
> +					netdev_state_change(dev);
> +				}
> +			}
> +			if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
> +				err = -EFAULT;
> +		} else
> +			err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
> +		break;
> +
> +	case SIOCDELTUNNEL:
> +		err = -EPERM;
> +		if (!capable(CAP_NET_ADMIN))
> +			goto done;
> +
> +		if (dev == ipn->fb_tunnel_dev) {
> +			err = -EFAULT;
> +			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
> +				goto done;
> +			err = -ENOENT;
> +
> +			t = vti_tunnel_locate(net, &p, 0);
> +			if (t == NULL)
> +				goto done;
> +			err = -EPERM;
> +			if (t->dev == ipn->fb_tunnel_dev)
> +				goto done;
> +			dev = t->dev;
> +		}
> +		unregister_netdevice(dev);
> +		err = 0;
> +		break;
> +
> +	default:
> +		err = -EINVAL;
> +	}
> +
> +done:
> +	return err;
> +}
> +
> +static int vti_tunnel_change_mtu(struct net_device *dev, int new_mtu)
> +{
> +	if (new_mtu < 68 || new_mtu > 0xFFF8)
> +		return -EINVAL;
> +	dev->mtu = new_mtu;
> +	return 0;
> +}
> +
> +static const struct net_device_ops vti_netdev_ops = {
> +	.ndo_init	= vti_tunnel_init,
> +	.ndo_uninit	= vti_tunnel_uninit,
> +	.ndo_start_xmit	= vti_tunnel_xmit,
> +	.ndo_do_ioctl	= vti_tunnel_ioctl,
> +	.ndo_change_mtu	= vti_tunnel_change_mtu,
> +	.ndo_get_stats64  = vti_get_stats64,
> +};
> +
> +static void vti_dev_free(struct net_device *dev)
> +{
> +	free_percpu(dev->tstats);
> +	free_netdev(dev);
> +}
> +
> +static void vti_tunnel_setup(struct net_device *dev)
> +{
> +	dev->netdev_ops		= &vti_netdev_ops;
> +	dev->destructor		= vti_dev_free;
> +
> +	dev->type		= ARPHRD_TUNNEL;
> +	dev->hard_header_len	= LL_MAX_HEADER + sizeof(struct iphdr);
> +	dev->mtu		= ETH_DATA_LEN;
> +	dev->flags		= IFF_NOARP;
> +	dev->iflink		= 0;
> +	dev->addr_len		= 4;
> +	dev->features		|= NETIF_F_NETNS_LOCAL;
> +	dev->features		|= NETIF_F_LLTX;
> +	dev->priv_flags		&= ~IFF_XMIT_DST_RELEASE;
> +}
> +
> +static int vti_tunnel_init(struct net_device *dev)
> +{
> +	struct ip_tunnel *tunnel = netdev_priv(dev);
> +
> +	tunnel->dev = dev;
> +	strcpy(tunnel->parms.name, dev->name);
> +
> +	memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
> +	memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
> +
> +	dev->tstats = alloc_percpu(struct pcpu_tstats);
> +	if (!dev->tstats)
> +		return -ENOMEM;
> +
> +	return 0;
> +}
> +
> +static int __net_init vti_fb_tunnel_init(struct net_device *dev)
> +{
> +	struct ip_tunnel *tunnel = netdev_priv(dev);
> +	struct iphdr *iph = &tunnel->parms.iph;
> +	struct vti_net *ipn = net_generic(dev_net(dev), vti_net_id);
> +
> +	tunnel->dev = dev;
> +	strcpy(tunnel->parms.name, dev->name);
> +
> +	iph->version		= 4;
> +	iph->protocol		= IPPROTO_ESP;

Why IPPROTO_ESP? What's with the other IPsec protocols?
Shouldn't this be IPPROTO_IPIP?

> +	iph->ihl		= 5;
> +
> +	dev->tstats = alloc_percpu(struct pcpu_tstats);
> +	if (!dev->tstats)
> +		return -ENOMEM;
> +
> +	dev_hold(dev);
> +	rcu_assign_pointer(ipn->tunnels_wc[0], tunnel);
> +	return 0;
> +}
> +
> +static struct xfrm_tunnel vti_handler __read_mostly = {
> +	.handler	=	vti_rcv,
> +	.err_handler	=	vti_err,
> +	.priority	=	1,
> +};
> +
> +static void vti_destroy_tunnels(struct vti_net *ipn, struct list_head *head)
> +{
> +	int prio;
> +
> +	for (prio = 1; prio < 4; prio++) {
> +		int h;
> +		for (h = 0; h < HASH_SIZE; h++) {
> +			struct ip_tunnel *t;
> +
> +			t = rtnl_dereference(ipn->tunnels[prio][h]);
> +			while (t != NULL) {
> +				unregister_netdevice_queue(t->dev, head);
> +				t = rtnl_dereference(t->next);
> +			}
> +		}
> +	}
> +}
> +
> +static int __net_init vti_init_net(struct net *net)
> +{
> +	int err;
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +
> +	ipn->tunnels[0] = ipn->tunnels_wc;
> +	ipn->tunnels[1] = ipn->tunnels_l;
> +	ipn->tunnels[2] = ipn->tunnels_r;
> +	ipn->tunnels[3] = ipn->tunnels_r_l;
> +
> +	ipn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel),
> +					   "ip_vti0",
> +					   vti_tunnel_setup);
> +	if (!ipn->fb_tunnel_dev) {
> +		err = -ENOMEM;
> +		goto err_alloc_dev;
> +	}
> +	dev_net_set(ipn->fb_tunnel_dev, net);
> +
> +	err = vti_fb_tunnel_init(ipn->fb_tunnel_dev);
> +	if (err)
> +		goto err_reg_dev;
> +	ipn->fb_tunnel_dev->rtnl_link_ops = &vti_link_ops;
> +
> +	err = register_netdev(ipn->fb_tunnel_dev);
> +	if (err)
> +		goto err_reg_dev;
> +	return 0;
> +
> +err_reg_dev:
> +	vti_dev_free(ipn->fb_tunnel_dev);
> +err_alloc_dev:
> +	/* nothing */
> +	return err;
> +}
> +
> +static void __net_exit vti_exit_net(struct net *net)
> +{
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +	LIST_HEAD(list);
> +
> +	rtnl_lock();
> +	vti_destroy_tunnels(ipn, &list);
> +	unregister_netdevice_many(&list);
> +	rtnl_unlock();
> +}
> +
> +static struct pernet_operations vti_net_ops = {
> +	.init = vti_init_net,
> +	.exit = vti_exit_net,
> +	.id   = &vti_net_id,
> +	.size = sizeof(struct vti_net),
> +};
> +
> +static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
> +{
> +	return 0;
> +}
> +
> +static void vti_netlink_parms(struct nlattr *data[],
> +				struct ip_tunnel_parm *parms)
> +{
> +	memset(parms, 0, sizeof(*parms));
> +
> +	parms->iph.protocol = IPPROTO_ESP;
> +
> +	if (!data)
> +		return;
> +
> +	if (data[IFLA_VTI_LINK])
> +		parms->link = nla_get_u32(data[IFLA_VTI_LINK]);
> +
> +	if (data[IFLA_VTI_IKEY])
> +		parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]);
> +
> +	if (data[IFLA_VTI_OKEY])
> +		parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]);
> +
> +	if (data[IFLA_VTI_LOCAL])
> +		parms->iph.saddr = nla_get_be32(data[IFLA_VTI_LOCAL]);
> +
> +	if (data[IFLA_VTI_REMOTE])
> +		parms->iph.daddr = nla_get_be32(data[IFLA_VTI_REMOTE]);
> +
> +}
> +
> +static int vti_newlink(struct net *src_net, struct net_device *dev, struct nlattr *tb[],
> +			 struct nlattr *data[])
> +{
> +	struct ip_tunnel *nt;
> +	struct net *net = dev_net(dev);
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +	int mtu;
> +	int err;
> +
> +	nt = netdev_priv(dev);
> +	vti_netlink_parms(data, &nt->parms);
> +
> +	if (vti_tunnel_locate(net, &nt->parms, 0))
> +		return -EEXIST;
> +
> +	mtu = vti_tunnel_bind_dev(dev);
> +	if (!tb[IFLA_MTU])
> +		dev->mtu = mtu;
> +
> +	err = register_netdevice(dev);
> +	if (err)
> +		goto out;
> +
> +	dev_hold(dev);
> +	vti_tunnel_link(ipn, nt);
> +
> +out:
> +	return err;
> +	return 0;
> +}
> +
> +static int vti_changelink(struct net_device *dev, struct nlattr *tb[],
> +			    struct nlattr *data[])
> +{
> +	struct ip_tunnel *t, *nt;
> +	struct net *net = dev_net(dev);
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +	struct ip_tunnel_parm p;
> +	int mtu;
> +
> +	if (dev == ipn->fb_tunnel_dev)
> +		return -EINVAL;
> +
> +	nt = netdev_priv(dev);
> +	vti_netlink_parms(data, &p);
> +
> +	t = vti_tunnel_locate(net, &p, 0);
> +
> +	if (t) {
> +		if (t->dev != dev)
> +			return -EEXIST;
> +	} else {
> +		t = nt;
> +
> +		vti_tunnel_unlink(ipn, t);
> +		t->parms.iph.saddr = p.iph.saddr;
> +		t->parms.iph.daddr = p.iph.daddr;
> +		t->parms.i_key = p.i_key;
> +		t->parms.o_key = p.o_key;
> +		if (dev->type != ARPHRD_ETHER) {
> +			memcpy(dev->dev_addr, &p.iph.saddr, 4);
> +			memcpy(dev->broadcast, &p.iph.daddr, 4);
> +		}
> +		vti_tunnel_link(ipn, t);
> +		netdev_state_change(dev);
> +	}
> +
> +	if (t->parms.link != p.link) {
> +		t->parms.link = p.link;
> +		mtu = vti_tunnel_bind_dev(dev);
> +		if (!tb[IFLA_MTU])
> +			dev->mtu = mtu;
> +		netdev_state_change(dev);
> +	}
> +
> +	return 0;
> +}
> +
> +static size_t vti_get_size(const struct net_device *dev)
> +{
> +	return
> +		/* IFLA_VTI_LINK */
> +		nla_total_size(4) +
> +		/* IFLA_VTI_IKEY */
> +		nla_total_size(4) +
> +		/* IFLA_VTI_OKEY */
> +		nla_total_size(4) +
> +		/* IFLA_VTI_LOCAL */
> +		nla_total_size(4) +
> +		/* IFLA_VTI_REMOTE */
> +		nla_total_size(4) +
> +		0;
> +}
> +
> +static int vti_fill_info(struct sk_buff *skb, const struct net_device *dev)
> +{
> +	struct ip_tunnel *t = netdev_priv(dev);
> +	struct ip_tunnel_parm *p = &t->parms;
> +
> +	nla_put_u32(skb, IFLA_VTI_LINK, p->link);
> +	nla_put_be32(skb, IFLA_VTI_IKEY, p->i_key);
> +	nla_put_be32(skb, IFLA_VTI_OKEY, p->o_key);
> +	nla_put_be32(skb, IFLA_VTI_LOCAL, p->iph.saddr);
> +	nla_put_be32(skb, IFLA_VTI_REMOTE, p->iph.daddr);
> +
> +	return 0;
> +}
> +
> +static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = {
> +	[IFLA_VTI_LINK]		= { .type = NLA_U32 },
> +	[IFLA_VTI_IKEY]		= { .type = NLA_U32 },
> +	[IFLA_VTI_OKEY]		= { .type = NLA_U32 },
> +	[IFLA_VTI_LOCAL]	= { .len = FIELD_SIZEOF(struct iphdr, saddr) },
> +	[IFLA_VTI_REMOTE]	= { .len = FIELD_SIZEOF(struct iphdr, daddr) },
> +};
> +
> +static struct rtnl_link_ops vti_link_ops __read_mostly = {
> +	.kind		= "vti",
> +	.maxtype	= IFLA_VTI_MAX,
> +	.policy		= vti_policy,
> +	.priv_size	= sizeof(struct ip_tunnel),
> +	.setup		= vti_tunnel_setup,
> +	.validate	= vti_tunnel_validate,
> +	.newlink	= vti_newlink,
> +	.changelink	= vti_changelink,
> +	.get_size	= vti_get_size,
> +	.fill_info	= vti_fill_info,
> +};
> +
> +static int __init vti_init(void)
> +{
> +	int err;
> +
> +	pr_info("IPv4 over ESP tunneling driver v4\n");
> +
> +	err = register_pernet_device(&vti_net_ops);
> +	if (err < 0)
> +		return err;
> +	err = xfrm4_mode_tunnel_input_register(&vti_handler);
> +	if (err < 0) {
> +		unregister_pernet_device(&vti_net_ops);
> +		pr_info(KERN_INFO "vti init: can't register tunnel\n");
> +	}
> +
> +	err = rtnl_link_register(&vti_link_ops);
> +	if (err < 0)
> +		goto rtnl_link_failed;
> +
> +	return err;
> +
> +rtnl_link_failed:
> +	xfrm4_mode_tunnel_input_deregister(&vti_handler);
> +	unregister_pernet_device(&vti_net_ops);
> +	return err;
> +}
> +
> +static void __exit vti_fini(void)
> +{
> +	rtnl_link_unregister(&vti_link_ops);
> +	if (xfrm4_mode_tunnel_input_deregister(&vti_handler))
> +		pr_info("vti close: can't deregister tunnel\n");
> +
> +	unregister_pernet_device(&vti_net_ops);
> +}
> +
> +module_init(vti_init);
> +module_exit(vti_fini);
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS_RTNL_LINK("vti");
> +MODULE_ALIAS_NETDEV("ip_vti0");
> --
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Steffen,
Thanks for your feedback. Responses are inline (@SM)


----- Original Message -----
From: "Steffen Klassert" <steffen.klassert@secunet.com>
To: "Saurabh" <saurabh.mohan@vyatta.com>
Cc: netdev@vger.kernel.org
Sent: Thursday, June 14, 2012 2:12:54 AM
Subject: Re: [net-next PATCH 02/02] net/ipv4: VTI support new module for ip_vti.

On Fri, Jun 08, 2012 at 10:32:53AM -0700, Saurabh wrote:
> 
> 
> New VTI tunnel kernel module, Kconfig and Makefile changes.

It is an interesting feature, do you plan for an IPv6
version too?
@SM: Yes, we do plan to do the same for ipv6. The timelines are not yet certain though.


I made some comments on the code below.

Thanks.

> 
> Signed-off-by: Saurabh Mohan <saurabh.mohan@vyatta.com>
> Reviewed-by: Stephen Hemminger <shemminger@vyatta.com>
> 
> ---
> diff --git a/include/linux/if_tunnel.h b/include/linux/if_tunnel.h
> index 16b92d0..4b4ce17 100644
> --- a/include/linux/if_tunnel.h
> +++ b/include/linux/if_tunnel.h
> @@ -80,4 +80,15 @@ enum {
>  
>  #define IFLA_GRE_MAX	(__IFLA_GRE_MAX - 1)
>  
> +enum {
> +	IFLA_VTI_UNSPEC,
> +	IFLA_VTI_LINK,
> +	IFLA_VTI_IKEY,
> +	IFLA_VTI_OKEY,
> +	IFLA_VTI_LOCAL,
> +	IFLA_VTI_REMOTE,
> +	__IFLA_VTI_MAX,
> +};
> +
> +#define IFLA_VTI_MAX	(__IFLA_VTI_MAX - 1)
>  #endif /* _IF_TUNNEL_H_ */
> diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
> index 20f1cb5..3a95308 100644
> --- a/net/ipv4/Kconfig
> +++ b/net/ipv4/Kconfig
> @@ -310,6 +310,20 @@ config SYN_COOKIES
>  
>  	  If unsure, say N.
>  
> +config NET_IPVTI
> +    tristate "Virtual (secure) IP: tunneling"
> +    select INET_TUNNEL

You added your register/deregister functions to net/ipv4/xfrm4_mode_tunnel.c,
so this should somehow select or depend on INET_XFRM_MODE_TUNNEL.

@SM: I'll create a dependency here.

> +    ---help---
> +      Tunneling means encapsulating data of one protocol type within
> +      another protocol and sending it over a channel that understands the
> +      Pencapsulating protocol. This particular tunneling driver implements
> +      encapsulation of IP within IP-ESP. This can be used with xfrm to give
> +      the notion of a secure tunnel and then use routing protocol on top.
> +
> +      Saying Y to this option will produce one module ( = code which can
> +      be inserted in and removed from the running kernel whenever you
> +      want). Most people won't need this and can say N.
> +
>  config INET_AH
>  	tristate "IP: AH transformation"
>  	select XFRM_ALGO
> diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
> index ff75d3b..3999ce9 100644
> --- a/net/ipv4/Makefile
> +++ b/net/ipv4/Makefile
> @@ -20,6 +20,7 @@ obj-$(CONFIG_IP_MROUTE) += ipmr.o
>  obj-$(CONFIG_NET_IPIP) += ipip.o
>  obj-$(CONFIG_NET_IPGRE_DEMUX) += gre.o
>  obj-$(CONFIG_NET_IPGRE) += ip_gre.o
> +obj-$(CONFIG_NET_IPVTI) += ip_vti.o
>  obj-$(CONFIG_SYN_COOKIES) += syncookies.o
>  obj-$(CONFIG_INET_AH) += ah4.o
>  obj-$(CONFIG_INET_ESP) += esp4.o
> diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
> new file mode 100644
> index 0000000..3eaa47c
> --- /dev/null
> +++ b/net/ipv4/ip_vti.c
> @@ -0,0 +1,980 @@
> +/*
> + *	Linux NET3:	IP/IP protocol decoder modified to support virtual tunnel interface
> + *
> + *	Authors:
> + *		Sam Lantinga (slouken@cs.ucdavis.edu)  02/01/95
> + *		Saurabh Mohan (saurabh.mohan@vyatta.com) 05/07/2012
> + *
> + *	This program is free software; you can redistribute it and/or
> + *	modify it under the terms of the GNU General Public License
> + *	as published by the Free Software Foundation; either version
> + *	2 of the License, or (at your option) any later version.
> + *
> + */
> +
> +/*
> +   This version of net/ipv4/ip_vti.c is cloned of net/ipv4/ipip.c
> +
> +   For comments look at net/ipv4/ip_gre.c --ANK
> + */
> +
> +
> +#include <linux/capability.h>
> +#include <linux/module.h>
> +#include <linux/types.h>
> +#include <linux/kernel.h>
> +#include <linux/uaccess.h>
> +#include <linux/skbuff.h>
> +#include <linux/netdevice.h>
> +#include <linux/in.h>
> +#include <linux/tcp.h>
> +#include <linux/udp.h>
> +#include <linux/if_arp.h>
> +#include <linux/mroute.h>
> +#include <linux/init.h>
> +#include <linux/netfilter_ipv4.h>
> +#include <linux/if_ether.h>
> +
> +#include <net/sock.h>
> +#include <net/ip.h>
> +#include <net/icmp.h>
> +#include <net/ipip.h>
> +#include <net/inet_ecn.h>
> +#include <net/xfrm.h>
> +#include <net/net_namespace.h>
> +#include <net/netns/generic.h>
> +
> +#define HASH_SIZE  16
> +#define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
> +
> +static struct rtnl_link_ops vti_link_ops __read_mostly;
> +
> +static int vti_net_id __read_mostly;
> +struct vti_net {
> +	struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
> +	struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
> +	struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
> +	struct ip_tunnel __rcu *tunnels_wc[1];
> +	struct ip_tunnel **tunnels[4];
> +
> +	struct net_device *fb_tunnel_dev;
> +};
> +
> +static int vti_fb_tunnel_init(struct net_device *dev);
> +static int vti_tunnel_init(struct net_device *dev);
> +static void vti_tunnel_setup(struct net_device *dev);
> +static void vti_dev_free(struct net_device *dev);
> +static int vti_tunnel_bind_dev(struct net_device *dev);
> +
> +/*
> + * Locking : hash tables are protected by RCU and RTNL
> + */
> +
> +#define for_each_ip_tunnel_rcu(start) \
> +	for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
> +
> +/* often modified stats are per cpu, other are shared (netdev->stats) */
> +struct pcpu_tstats {
> +	u64	rx_packets;
> +	u64	rx_bytes;
> +	u64	tx_packets;
> +	u64	tx_bytes;
> +	struct	u64_stats_sync	syncp;
> +};
> +
> +#define VTI_XMIT(stats1, stats2) do {				\
> +	int err;						\
> +	int pkt_len = skb->len;					\
> +	err = dst_output(skb);					\
> +	if (net_xmit_eval(err) == 0) {				\
> +		(stats1)->tx_bytes += pkt_len;			\
> +		(stats1)->tx_packets++;				\
> +	} else {						\
> +		(stats2)->tx_errors++;				\
> +		(stats2)->tx_aborted_errors++;			\
> +	}							\
> +} while (0)
> +
> +
> +static struct rtnl_link_stats64 *vti_get_stats64(struct net_device *dev,
> +					       struct rtnl_link_stats64 *tot)
> +{
> +	int i;
> +
> +	for_each_possible_cpu(i) {
> +		const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);
> +		u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
> +		unsigned int start;
> +
> +		do {
> +			start = u64_stats_fetch_begin_bh(&tstats->syncp);
> +			rx_packets = tstats->rx_packets;
> +			tx_packets = tstats->tx_packets;
> +			rx_bytes = tstats->rx_bytes;
> +			tx_bytes = tstats->tx_bytes;
> +		} while (u64_stats_fetch_retry_bh(&tstats->syncp, start));
> +
> +		tot->rx_packets += rx_packets;
> +		tot->tx_packets += tx_packets;
> +		tot->rx_bytes   += rx_bytes;
> +		tot->tx_bytes   += tx_bytes;
> +	}
> +
> +	tot->multicast = dev->stats.multicast;
> +	tot->rx_crc_errors = dev->stats.rx_crc_errors;
> +	tot->rx_fifo_errors = dev->stats.rx_fifo_errors;
> +	tot->rx_length_errors = dev->stats.rx_length_errors;
> +	tot->rx_errors = dev->stats.rx_errors;
> +	tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
> +	tot->tx_carrier_errors = dev->stats.tx_carrier_errors;
> +	tot->tx_dropped = dev->stats.tx_dropped;
> +	tot->tx_aborted_errors = dev->stats.tx_aborted_errors;
> +	tot->tx_errors = dev->stats.tx_errors;
> +
> +	return tot;
> +}
> +
> +static struct ip_tunnel *vti_tunnel_lookup(struct net *net,
> +					 __be32 remote, __be32 local)
> +{
> +	unsigned h0 = HASH(remote);
> +	unsigned h1 = HASH(local);
> +	struct ip_tunnel *t;
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +
> +	for_each_ip_tunnel_rcu(ipn->tunnels_r_l[h0 ^ h1])
> +		if (local == t->parms.iph.saddr &&
> +		    remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
> +			return t;
> +	for_each_ip_tunnel_rcu(ipn->tunnels_r[h0])
> +		if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
> +			return t;
> +
> +	for_each_ip_tunnel_rcu(ipn->tunnels_l[h1])
> +		if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
> +			return t;
> +
> +	for_each_ip_tunnel_rcu(ipn->tunnels_wc[0])
> +		if (t && (t->dev->flags&IFF_UP))
> +			return t;
> +	return NULL;
> +}
> +
> +static struct ip_tunnel **__vti_bucket(struct vti_net *ipn,
> +				     struct ip_tunnel_parm *parms)
> +{
> +	__be32 remote = parms->iph.daddr;
> +	__be32 local = parms->iph.saddr;
> +	unsigned h = 0;
> +	int prio = 0;
> +
> +	if (remote) {
> +		prio |= 2;
> +		h ^= HASH(remote);
> +	}
> +	if (local) {
> +		prio |= 1;
> +		h ^= HASH(local);
> +	}
> +	return &ipn->tunnels[prio][h];
> +}
> +
> +static inline struct ip_tunnel **vti_bucket(struct vti_net *ipn,
> +					  struct ip_tunnel *t)
> +{
> +	return __vti_bucket(ipn, &t->parms);
> +}
> +
> +static void vti_tunnel_unlink(struct vti_net *ipn, struct ip_tunnel *t)
> +{
> +	struct ip_tunnel __rcu **tp;
> +	struct ip_tunnel *iter;
> +
> +	for (tp = vti_bucket(ipn, t);
> +	     (iter = rtnl_dereference(*tp)) != NULL;
> +	     tp = &iter->next) {
> +		if (t == iter) {
> +			rcu_assign_pointer(*tp, t->next);
> +			break;
> +		}
> +	}
> +}
> +
> +static void vti_tunnel_link(struct vti_net *ipn, struct ip_tunnel *t)
> +{
> +	struct ip_tunnel __rcu **tp = vti_bucket(ipn, t);
> +
> +	rcu_assign_pointer(t->next, rtnl_dereference(*tp));
> +	rcu_assign_pointer(*tp, t);
> +}
> +
> +static struct ip_tunnel *vti_tunnel_locate(struct net *net,
> +					 struct ip_tunnel_parm *parms,
> +					 int create)
> +{
> +	__be32 remote = parms->iph.daddr;
> +	__be32 local = parms->iph.saddr;
> +	struct ip_tunnel *t, *nt;
> +	struct ip_tunnel __rcu **tp;
> +	struct net_device *dev;
> +	char name[IFNAMSIZ];
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +
> +	for (tp = __vti_bucket(ipn, parms);
> +	     (t = rtnl_dereference(*tp)) != NULL;
> +	     tp = &t->next) {
> +		if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
> +			return t;
> +	}
> +	if (!create)
> +		return NULL;
> +
> +	if (parms->name[0])
> +		strlcpy(name, parms->name, IFNAMSIZ);
> +	else
> +		strcpy(name, "vti%d");
> +
> +	dev = alloc_netdev(sizeof(*t), name, vti_tunnel_setup);
> +	if (dev == NULL)
> +		return NULL;
> +
> +	dev_net_set(dev, net);
> +
> +	nt = netdev_priv(dev);
> +	nt->parms = *parms;
> +	dev->rtnl_link_ops = &vti_link_ops;
> +
> +	vti_tunnel_bind_dev(dev);
> +
> +	if (register_netdevice(dev) < 0)
> +		goto failed_free;
> +
> +	dev_hold(dev);
> +	vti_tunnel_link(ipn, nt);
> +	return nt;
> +
> + failed_free:
> +	free_netdev(dev);
> +	return NULL;
> +}
> +
> +static void vti_tunnel_uninit(struct net_device *dev)
> +{
> +	struct net *net = dev_net(dev);
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +
> +	if (dev == ipn->fb_tunnel_dev)
> +		RCU_INIT_POINTER(ipn->tunnels_wc[0], NULL);
> +	else
> +		vti_tunnel_unlink(ipn, netdev_priv(dev));
> +	dev_put(dev);
> +}
> +
> +static int vti_err(struct sk_buff *skb, u32 info)
> +{
> +
> +	/* All the routers (except for Linux) return only
> +	 * 8 bytes of packet payload. It means, that precise relaying of
> +	 * ICMP in the real Internet is absolutely infeasible.
> +	 */
> +	struct iphdr *iph = (struct iphdr *)skb->data;
> +	const int type = icmp_hdr(skb)->type;
> +	const int code = icmp_hdr(skb)->code;
> +	struct ip_tunnel *t;
> +	int err;
> +
> +	switch (type) {
> +	default:
> +	case ICMP_PARAMETERPROB:
> +		return 0;
> +
> +	case ICMP_DEST_UNREACH:
> +		switch (code) {
> +		case ICMP_SR_FAILED:
> +		case ICMP_PORT_UNREACH:
> +			/* Impossible event. */
> +			return 0;
> +		case ICMP_FRAG_NEEDED:
> +			/* Soft state for pmtu is maintained by IP core. */
> +			return 0;
> +		default:
> +			/* All others are translated to HOST_UNREACH. */
> +			break;
> +		}
> +		break;
> +	case ICMP_TIME_EXCEEDED:
> +		if (code != ICMP_EXC_TTL)
> +			return 0;
> +		break;
> +	}
> +
> +	err = -ENOENT;
> +
> +	rcu_read_lock();
> +	t = vti_tunnel_lookup(dev_net(skb->dev), iph->daddr, iph->saddr);
> +	if (t == NULL || t->parms.iph.daddr == 0)
> +		goto out;
> +
> +	err = 0;
> +	if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
> +		goto out;
> +
> +	if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
> +		t->err_count++;
> +	else
> +		t->err_count = 1;
> +	t->err_time = jiffies;
> +out:
> +	rcu_read_unlock();
> +	return err;
> +}
> +
> +static inline void vti_ecn_decapsulate(const struct iphdr *outer_iph,
> +					struct sk_buff *skb)
> +{
> +	struct iphdr *inner_iph = ip_hdr(skb);
> +
> +	if (INET_ECN_is_ce(outer_iph->tos))
> +		IP_ECN_set_ce(inner_iph);
> +}

vti_ecn_decapsulate is unused.
@SM: Thx!

> +
> +/*
> + * We dont digest the packet therefore let the packet pass.
> + */
> +static int vti_rcv(struct sk_buff *skb)
> +{
> +	struct ip_tunnel *tunnel;
> +	const struct iphdr *iph = ip_hdr(skb);
> +
> +	rcu_read_lock();
> +	tunnel = vti_tunnel_lookup(dev_net(skb->dev), iph->saddr, iph->daddr);
> +	if (tunnel != NULL) {
> +		struct pcpu_tstats *tstats;
> +
> +		tstats = this_cpu_ptr(tunnel->dev->tstats);
> +		tstats->rx_packets++;
> +		tstats->rx_bytes += skb->len;
> +
> +		skb->dev = tunnel->dev;
> +		skb_dst_drop(skb);

Really need to drop a refcount here? xfrm_input() does that too before
it reinjects the packet into layer 2.

> +		nf_reset(skb);

Same here.

@SM: Incorporated both.

> +		rcu_read_unlock();
> +		/* We do not eat the packet here therefore return 1 */
> +		return 1;
> +	}
> +	rcu_read_unlock();
> +
> +	return -1;
> +}
> +
> +/*
> + *	This function assumes it is being called from dev_queue_xmit()
> + *	and that skb is filled properly by that function.
> + */
> +
> +static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
> +{
> +	struct ip_tunnel *tunnel = netdev_priv(dev);
> +	struct pcpu_tstats *tstats;
> +	struct net_device_stats *stats = &tunnel->dev->stats;
> +	struct iphdr  *tiph = &tunnel->parms.iph;
> +	u8     tos = tunnel->parms.iph.tos;
> +	struct rtable *rt;		/* Route to the other host */
> +	struct net_device *tdev;	/* Device to other host */
> +	struct iphdr  *old_iph = ip_hdr(skb);
> +	__be32 dst = tiph->daddr;
> +	struct flowi4 fl4;
> +
> +	if (skb->protocol != htons(ETH_P_IP))
> +		goto tx_error;
> +
> +	if (tos&1)
> +		tos = old_iph->tos;
> +
> +	if (!dst) {
> +		/* NBMA tunnel */
> +		rt = skb_rtable(skb);
> +		if (rt == NULL) {
> +			stats->tx_fifo_errors++;
> +			goto tx_error;
> +		}
> +		dst = rt->rt_gateway;
> +		if (dst == 0)
> +			goto tx_error_icmp;
> +	}
> +
> +	memset(&fl4, 0, sizeof(fl4));
> +	flowi4_init_output(&fl4, tunnel->parms.link,
> +		htonl(tunnel->parms.i_key), RT_TOS(tos), RT_SCOPE_UNIVERSE,
> +		IPPROTO_IPIP, 0,
> +		dst, tiph->saddr, 0, 0);
> +	rt = ip_route_output_key(dev_net(dev), &fl4);
> +	if (IS_ERR(rt)) {
> +		dev->stats.tx_carrier_errors++;
> +		goto tx_error_icmp;
> +	}
> +#ifdef CONFIG_XFRM
> +		/* if there is no transform then this tunnel is not functional. */
> +		if (!rt->dst.xfrm) {
> +			stats->tx_carrier_errors++;
> +			goto tx_error_icmp;
> +		}
> +#endif
> +	tdev = rt->dst.dev;
> +
> +	if (tdev == dev) {
> +		ip_rt_put(rt);
> +		stats->collisions++;
> +		goto tx_error;
> +
> +	}
> +
> +
> +	if (tunnel->err_count > 0) {
> +		if (time_before(jiffies,
> +				tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
> +			tunnel->err_count--;
> +			dst_link_failure(skb);
> +		} else
> +			tunnel->err_count = 0;
> +	}
> +
> +
> +	IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
> +			      IPSKB_REROUTED);
> +	skb_dst_drop(skb);
> +	skb_dst_set(skb, &rt->dst);
> +	nf_reset(skb);
> +	skb->dev = skb_dst(skb)->dev;
> +
> +	tstats = this_cpu_ptr(dev->tstats);
> +	VTI_XMIT(tstats, &dev->stats);
> +	return NETDEV_TX_OK;
> +
> +tx_error_icmp:
> +	dst_link_failure(skb);
> +tx_error:
> +	stats->tx_errors++;
> +	dev_kfree_skb(skb);
> +	return NETDEV_TX_OK;
> +}
> +
> +static int vti_tunnel_bind_dev(struct net_device *dev)
> +{
> +	struct net_device *tdev = NULL;
> +	struct ip_tunnel *tunnel;
> +	struct iphdr *iph;
> +
> +	tunnel = netdev_priv(dev);
> +	iph = &tunnel->parms.iph;
> +
> +	if (iph->daddr) {
> +		struct rtable *rt;
> +		struct flowi4 fl4;
> +		memset(&fl4, 0, sizeof(fl4));
> +		flowi4_init_output(&fl4, tunnel->parms.link,
> +				htonl(tunnel->parms.i_key), RT_TOS(iph->tos), RT_SCOPE_UNIVERSE,
> +				IPPROTO_IPIP, 0,
> +				iph->daddr, iph->saddr, 0, 0);
> +		rt = ip_route_output_key(dev_net(dev), &fl4);
> +		if (!IS_ERR(rt)) {
> +			tdev = rt->dst.dev;
> +			ip_rt_put(rt);
> +		}
> +		dev->flags |= IFF_POINTOPOINT;
> +	}
> +
> +	if (!tdev && tunnel->parms.link)
> +		tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
> +
> +	if (tdev) {
> +		dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
> +		dev->mtu = tdev->mtu;
> +	}
> +	dev->iflink = tunnel->parms.link;
> +	return dev->mtu;
> +}
> +
> +static int
> +vti_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
> +{
> +	int err = 0;
> +	struct ip_tunnel_parm p;
> +	struct ip_tunnel *t;
> +	struct net *net = dev_net(dev);
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +
> +	switch (cmd) {
> +	case SIOCGETTUNNEL:
> +		t = NULL;
> +		if (dev == ipn->fb_tunnel_dev) {
> +			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
> +				err = -EFAULT;
> +				break;
> +			}
> +			t = vti_tunnel_locate(net, &p, 0);
> +		}
> +		if (t == NULL)
> +			t = netdev_priv(dev);
> +		memcpy(&p, &t->parms, sizeof(p));
> +		p.i_flags |= GRE_KEY;
> +		p.o_flags |= GRE_KEY;
> +		if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
> +			err = -EFAULT;
> +		break;
> +
> +	case SIOCADDTUNNEL:
> +	case SIOCCHGTUNNEL:
> +		err = -EPERM;
> +		if (!capable(CAP_NET_ADMIN))
> +			goto done;
> +
> +		err = -EFAULT;
> +		if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
> +			goto done;
> +
> +		err = -EINVAL;
> +		if (p.iph.version != 4 || p.iph.protocol != IPPROTO_ESP ||
> +		    p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
> +			goto done;
> +		if (p.iph.ttl)
> +			p.iph.frag_off |= htons(IP_DF);
> +
> +		t = vti_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
> +
> +		if (dev != ipn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
> +			if (t != NULL) {
> +				if (t->dev != dev) {
> +					err = -EEXIST;
> +					break;
> +				}
> +			} else {
> +				if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
> +				    (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
> +					err = -EINVAL;
> +					break;
> +				}
> +				t = netdev_priv(dev);
> +				vti_tunnel_unlink(ipn, t);
> +				synchronize_net();
> +				t->parms.iph.saddr = p.iph.saddr;
> +				t->parms.iph.daddr = p.iph.daddr;
> +				t->parms.i_key = p.i_key;
> +				t->parms.o_key = p.o_key;
> +				t->parms.iph.protocol = IPPROTO_ESP;
> +				memcpy(dev->dev_addr, &p.iph.saddr, 4);
> +				memcpy(dev->broadcast, &p.iph.daddr, 4);
> +				vti_tunnel_link(ipn, t);
> +				netdev_state_change(dev);
> +			}
> +		}
> +
> +		if (t) {
> +			err = 0;
> +			if (cmd == SIOCCHGTUNNEL) {
> +				t->parms.iph.ttl = p.iph.ttl;
> +				t->parms.iph.tos = p.iph.tos;
> +				t->parms.iph.frag_off = p.iph.frag_off;
> +				t->parms.i_key = p.i_key;
> +				t->parms.o_key = p.o_key;
> +				if (t->parms.link != p.link) {
> +					t->parms.link = p.link;
> +					vti_tunnel_bind_dev(dev);
> +					netdev_state_change(dev);
> +				}
> +			}
> +			if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
> +				err = -EFAULT;
> +		} else
> +			err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
> +		break;
> +
> +	case SIOCDELTUNNEL:
> +		err = -EPERM;
> +		if (!capable(CAP_NET_ADMIN))
> +			goto done;
> +
> +		if (dev == ipn->fb_tunnel_dev) {
> +			err = -EFAULT;
> +			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
> +				goto done;
> +			err = -ENOENT;
> +
> +			t = vti_tunnel_locate(net, &p, 0);
> +			if (t == NULL)
> +				goto done;
> +			err = -EPERM;
> +			if (t->dev == ipn->fb_tunnel_dev)
> +				goto done;
> +			dev = t->dev;
> +		}
> +		unregister_netdevice(dev);
> +		err = 0;
> +		break;
> +
> +	default:
> +		err = -EINVAL;
> +	}
> +
> +done:
> +	return err;
> +}
> +
> +static int vti_tunnel_change_mtu(struct net_device *dev, int new_mtu)
> +{
> +	if (new_mtu < 68 || new_mtu > 0xFFF8)
> +		return -EINVAL;
> +	dev->mtu = new_mtu;
> +	return 0;
> +}
> +
> +static const struct net_device_ops vti_netdev_ops = {
> +	.ndo_init	= vti_tunnel_init,
> +	.ndo_uninit	= vti_tunnel_uninit,
> +	.ndo_start_xmit	= vti_tunnel_xmit,
> +	.ndo_do_ioctl	= vti_tunnel_ioctl,
> +	.ndo_change_mtu	= vti_tunnel_change_mtu,
> +	.ndo_get_stats64  = vti_get_stats64,
> +};
> +
> +static void vti_dev_free(struct net_device *dev)
> +{
> +	free_percpu(dev->tstats);
> +	free_netdev(dev);
> +}
> +
> +static void vti_tunnel_setup(struct net_device *dev)
> +{
> +	dev->netdev_ops		= &vti_netdev_ops;
> +	dev->destructor		= vti_dev_free;
> +
> +	dev->type		= ARPHRD_TUNNEL;
> +	dev->hard_header_len	= LL_MAX_HEADER + sizeof(struct iphdr);
> +	dev->mtu		= ETH_DATA_LEN;
> +	dev->flags		= IFF_NOARP;
> +	dev->iflink		= 0;
> +	dev->addr_len		= 4;
> +	dev->features		|= NETIF_F_NETNS_LOCAL;
> +	dev->features		|= NETIF_F_LLTX;
> +	dev->priv_flags		&= ~IFF_XMIT_DST_RELEASE;
> +}
> +
> +static int vti_tunnel_init(struct net_device *dev)
> +{
> +	struct ip_tunnel *tunnel = netdev_priv(dev);
> +
> +	tunnel->dev = dev;
> +	strcpy(tunnel->parms.name, dev->name);
> +
> +	memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
> +	memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
> +
> +	dev->tstats = alloc_percpu(struct pcpu_tstats);
> +	if (!dev->tstats)
> +		return -ENOMEM;
> +
> +	return 0;
> +}
> +
> +static int __net_init vti_fb_tunnel_init(struct net_device *dev)
> +{
> +	struct ip_tunnel *tunnel = netdev_priv(dev);
> +	struct iphdr *iph = &tunnel->parms.iph;
> +	struct vti_net *ipn = net_generic(dev_net(dev), vti_net_id);
> +
> +	tunnel->dev = dev;
> +	strcpy(tunnel->parms.name, dev->name);
> +
> +	iph->version		= 4;
> +	iph->protocol		= IPPROTO_ESP;

Why IPPROTO_ESP? What's with the other IPsec protocols?
Shouldn't this be IPPROTO_IPIP?

@SM: VTI will work only with ESP not with AH (at least I have never heard of any one using it with AH). Plus I wanted to keep this module separate from IPIP (ip-in-ip tunnels).

I'll resubmit the patch with the changes tested.
-Saurabh.
> +	iph->ihl		= 5;
> +
> +	dev->tstats = alloc_percpu(struct pcpu_tstats);
> +	if (!dev->tstats)
> +		return -ENOMEM;
> +
> +	dev_hold(dev);
> +	rcu_assign_pointer(ipn->tunnels_wc[0], tunnel);
> +	return 0;
> +}
> +
> +static struct xfrm_tunnel vti_handler __read_mostly = {
> +	.handler	=	vti_rcv,
> +	.err_handler	=	vti_err,
> +	.priority	=	1,
> +};
> +
> +static void vti_destroy_tunnels(struct vti_net *ipn, struct list_head *head)
> +{
> +	int prio;
> +
> +	for (prio = 1; prio < 4; prio++) {
> +		int h;
> +		for (h = 0; h < HASH_SIZE; h++) {
> +			struct ip_tunnel *t;
> +
> +			t = rtnl_dereference(ipn->tunnels[prio][h]);
> +			while (t != NULL) {
> +				unregister_netdevice_queue(t->dev, head);
> +				t = rtnl_dereference(t->next);
> +			}
> +		}
> +	}
> +}
> +
> +static int __net_init vti_init_net(struct net *net)
> +{
> +	int err;
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +
> +	ipn->tunnels[0] = ipn->tunnels_wc;
> +	ipn->tunnels[1] = ipn->tunnels_l;
> +	ipn->tunnels[2] = ipn->tunnels_r;
> +	ipn->tunnels[3] = ipn->tunnels_r_l;
> +
> +	ipn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel),
> +					   "ip_vti0",
> +					   vti_tunnel_setup);
> +	if (!ipn->fb_tunnel_dev) {
> +		err = -ENOMEM;
> +		goto err_alloc_dev;
> +	}
> +	dev_net_set(ipn->fb_tunnel_dev, net);
> +
> +	err = vti_fb_tunnel_init(ipn->fb_tunnel_dev);
> +	if (err)
> +		goto err_reg_dev;
> +	ipn->fb_tunnel_dev->rtnl_link_ops = &vti_link_ops;
> +
> +	err = register_netdev(ipn->fb_tunnel_dev);
> +	if (err)
> +		goto err_reg_dev;
> +	return 0;
> +
> +err_reg_dev:
> +	vti_dev_free(ipn->fb_tunnel_dev);
> +err_alloc_dev:
> +	/* nothing */
> +	return err;
> +}
> +
> +static void __net_exit vti_exit_net(struct net *net)
> +{
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +	LIST_HEAD(list);
> +
> +	rtnl_lock();
> +	vti_destroy_tunnels(ipn, &list);
> +	unregister_netdevice_many(&list);
> +	rtnl_unlock();
> +}
> +
> +static struct pernet_operations vti_net_ops = {
> +	.init = vti_init_net,
> +	.exit = vti_exit_net,
> +	.id   = &vti_net_id,
> +	.size = sizeof(struct vti_net),
> +};
> +
> +static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
> +{
> +	return 0;
> +}
> +
> +static void vti_netlink_parms(struct nlattr *data[],
> +				struct ip_tunnel_parm *parms)
> +{
> +	memset(parms, 0, sizeof(*parms));
> +
> +	parms->iph.protocol = IPPROTO_ESP;
> +
> +	if (!data)
> +		return;
> +
> +	if (data[IFLA_VTI_LINK])
> +		parms->link = nla_get_u32(data[IFLA_VTI_LINK]);
> +
> +	if (data[IFLA_VTI_IKEY])
> +		parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]);
> +
> +	if (data[IFLA_VTI_OKEY])
> +		parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]);
> +
> +	if (data[IFLA_VTI_LOCAL])
> +		parms->iph.saddr = nla_get_be32(data[IFLA_VTI_LOCAL]);
> +
> +	if (data[IFLA_VTI_REMOTE])
> +		parms->iph.daddr = nla_get_be32(data[IFLA_VTI_REMOTE]);
> +
> +}
> +
> +static int vti_newlink(struct net *src_net, struct net_device *dev, struct nlattr *tb[],
> +			 struct nlattr *data[])
> +{
> +	struct ip_tunnel *nt;
> +	struct net *net = dev_net(dev);
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +	int mtu;
> +	int err;
> +
> +	nt = netdev_priv(dev);
> +	vti_netlink_parms(data, &nt->parms);
> +
> +	if (vti_tunnel_locate(net, &nt->parms, 0))
> +		return -EEXIST;
> +
> +	mtu = vti_tunnel_bind_dev(dev);
> +	if (!tb[IFLA_MTU])
> +		dev->mtu = mtu;
> +
> +	err = register_netdevice(dev);
> +	if (err)
> +		goto out;
> +
> +	dev_hold(dev);
> +	vti_tunnel_link(ipn, nt);
> +
> +out:
> +	return err;
> +	return 0;
> +}
> +
> +static int vti_changelink(struct net_device *dev, struct nlattr *tb[],
> +			    struct nlattr *data[])
> +{
> +	struct ip_tunnel *t, *nt;
> +	struct net *net = dev_net(dev);
> +	struct vti_net *ipn = net_generic(net, vti_net_id);
> +	struct ip_tunnel_parm p;
> +	int mtu;
> +
> +	if (dev == ipn->fb_tunnel_dev)
> +		return -EINVAL;
> +
> +	nt = netdev_priv(dev);
> +	vti_netlink_parms(data, &p);
> +
> +	t = vti_tunnel_locate(net, &p, 0);
> +
> +	if (t) {
> +		if (t->dev != dev)
> +			return -EEXIST;
> +	} else {
> +		t = nt;
> +
> +		vti_tunnel_unlink(ipn, t);
> +		t->parms.iph.saddr = p.iph.saddr;
> +		t->parms.iph.daddr = p.iph.daddr;
> +		t->parms.i_key = p.i_key;
> +		t->parms.o_key = p.o_key;
> +		if (dev->type != ARPHRD_ETHER) {
> +			memcpy(dev->dev_addr, &p.iph.saddr, 4);
> +			memcpy(dev->broadcast, &p.iph.daddr, 4);
> +		}
> +		vti_tunnel_link(ipn, t);
> +		netdev_state_change(dev);
> +	}
> +
> +	if (t->parms.link != p.link) {
> +		t->parms.link = p.link;
> +		mtu = vti_tunnel_bind_dev(dev);
> +		if (!tb[IFLA_MTU])
> +			dev->mtu = mtu;
> +		netdev_state_change(dev);
> +	}
> +
> +	return 0;
> +}
> +
> +static size_t vti_get_size(const struct net_device *dev)
> +{
> +	return
> +		/* IFLA_VTI_LINK */
> +		nla_total_size(4) +
> +		/* IFLA_VTI_IKEY */
> +		nla_total_size(4) +
> +		/* IFLA_VTI_OKEY */
> +		nla_total_size(4) +
> +		/* IFLA_VTI_LOCAL */
> +		nla_total_size(4) +
> +		/* IFLA_VTI_REMOTE */
> +		nla_total_size(4) +
> +		0;
> +}
> +
> +static int vti_fill_info(struct sk_buff *skb, const struct net_device *dev)
> +{
> +	struct ip_tunnel *t = netdev_priv(dev);
> +	struct ip_tunnel_parm *p = &t->parms;
> +
> +	nla_put_u32(skb, IFLA_VTI_LINK, p->link);
> +	nla_put_be32(skb, IFLA_VTI_IKEY, p->i_key);
> +	nla_put_be32(skb, IFLA_VTI_OKEY, p->o_key);
> +	nla_put_be32(skb, IFLA_VTI_LOCAL, p->iph.saddr);
> +	nla_put_be32(skb, IFLA_VTI_REMOTE, p->iph.daddr);
> +
> +	return 0;
> +}
> +
> +static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = {
> +	[IFLA_VTI_LINK]		= { .type = NLA_U32 },
> +	[IFLA_VTI_IKEY]		= { .type = NLA_U32 },
> +	[IFLA_VTI_OKEY]		= { .type = NLA_U32 },
> +	[IFLA_VTI_LOCAL]	= { .len = FIELD_SIZEOF(struct iphdr, saddr) },
> +	[IFLA_VTI_REMOTE]	= { .len = FIELD_SIZEOF(struct iphdr, daddr) },
> +};
> +
> +static struct rtnl_link_ops vti_link_ops __read_mostly = {
> +	.kind		= "vti",
> +	.maxtype	= IFLA_VTI_MAX,
> +	.policy		= vti_policy,
> +	.priv_size	= sizeof(struct ip_tunnel),
> +	.setup		= vti_tunnel_setup,
> +	.validate	= vti_tunnel_validate,
> +	.newlink	= vti_newlink,
> +	.changelink	= vti_changelink,
> +	.get_size	= vti_get_size,
> +	.fill_info	= vti_fill_info,
> +};
> +
> +static int __init vti_init(void)
> +{
> +	int err;
> +
> +	pr_info("IPv4 over ESP tunneling driver v4\n");
> +
> +	err = register_pernet_device(&vti_net_ops);
> +	if (err < 0)
> +		return err;
> +	err = xfrm4_mode_tunnel_input_register(&vti_handler);
> +	if (err < 0) {
> +		unregister_pernet_device(&vti_net_ops);
> +		pr_info(KERN_INFO "vti init: can't register tunnel\n");
> +	}
> +
> +	err = rtnl_link_register(&vti_link_ops);
> +	if (err < 0)
> +		goto rtnl_link_failed;
> +
> +	return err;
> +
> +rtnl_link_failed:
> +	xfrm4_mode_tunnel_input_deregister(&vti_handler);
> +	unregister_pernet_device(&vti_net_ops);
> +	return err;
> +}
> +
> +static void __exit vti_fini(void)
> +{
> +	rtnl_link_unregister(&vti_link_ops);
> +	if (xfrm4_mode_tunnel_input_deregister(&vti_handler))
> +		pr_info("vti close: can't deregister tunnel\n");
> +
> +	unregister_pernet_device(&vti_net_ops);
> +}
> +
> +module_init(vti_init);
> +module_exit(vti_fini);
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS_RTNL_LINK("vti");
> +MODULE_ALIAS_NETDEV("ip_vti0");
> --
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From: Saurabh Mohan <saurabh.mohan@vyatta.com>
Date: Thu, 14 Jun 2012 19:43:59 -0700 (PDT)

> Thanks for your feedback. Responses are inline (@SM)
 ...
> @SM: Yes, we do plan to do the same for ipv6. The timelines are not yet certain though.

Top-posting and using this special "@FOO" way of replying to other
people's emails is extremely hard to read and follow.

Please use normal email quotation mannerisms to reply to people,
otherwise many developers will simply give much lower precedence to
your postings or flat out ignore them altogether.

Thank you.
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On Thu, Jun 14, 2012 at 07:43:59PM -0700, Saurabh Mohan wrote:
> > +
> > +	iph->version		= 4;
> > +	iph->protocol		= IPPROTO_ESP;
> 
> Why IPPROTO_ESP? What's with the other IPsec protocols?
> Shouldn't this be IPPROTO_IPIP?
> 
> @SM: VTI will work only with ESP not with AH (at least I have never heard of any one using it with AH). Plus I wanted to keep this module separate from IPIP (ip-in-ip tunnels).
> 

VTI should be independent of the IPsec protocol.
Our IPsec implementation supports AH (and IPCOMP)
so VTI should support these protocols too.

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----- Original Message -----
> On Thu, Jun 14, 2012 at 07:43:59PM -0700, Saurabh Mohan wrote:
> > > +
> > > +	iph->version		= 4;
> > > +	iph->protocol		= IPPROTO_ESP;
> > 
> > Why IPPROTO_ESP? What's with the other IPsec protocols?
> > Shouldn't this be IPPROTO_IPIP?
> > 
> > @SM: VTI will work only with ESP not with AH (at least I have never
> > heard of any one using it with AH). Plus I wanted to keep this
> > module separate from IPIP (ip-in-ip tunnels).
> > 
> 
> VTI should be independent of the IPsec protocol.
> Our IPsec implementation supports AH (and IPCOMP)
> so VTI should support these protocols too.
> 
> 
That is not the intent of this feature. It is only meant to support ESP-tunnel mode. I don't know what your implementation is. 
There are many ways to skin a cat. This is just one way and that is why this feature has been implemented as a module. Thus making it optional for use.
If your objection is that I called it VTI, then I can call it "ip_esp" or something similar.

A few ppl have expressed interest in this implementation and have asked for more details and enhancements. Clearly they and our customers find it useful.
I'll resubmit with the code fixes you had mentioned.
-Saurabh
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From: Steffen Klassert <steffen.klassert@secunet.com>
Date: Fri, 15 Jun 2012 07:37:07 +0200

> VTI should be independent of the IPsec protocol.
> Our IPsec implementation supports AH (and IPCOMP)
> so VTI should support these protocols too.

I agree with Steffen, it shouldn't require very much work to support
all of the 3 major IPSEC protocols.  So if we are going to add a
feature like this I require that you completely flesh out the support
and support IPV6 as well.

Doing otherwise creates a terrible user experience.
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