/*
* Copyright (c) 2007-2013 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/if.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/if_tunnel.h>
#include <linux/if_vlan.h>
#include <linux/in.h>
#include <linux/if_vlan.h>
#include <linux/in.h>
#include <linux/in_route.h>
#include <linux/inetdevice.h>
#include <linux/jhash.h>
#include <linux/list.h>
#include <linux/kernel.h>
#include <linux/workqueue.h>
#include <linux/rculist.h>
#include <net/route.h>
#include <net/xfrm.h>
#include <net/icmp.h>
#include <net/ip.h>
#include <net/ip_tunnels.h>
#include <net/gre.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/protocol.h>
#include "datapath.h"
#include "vport.h"
/* Returns the least-significant 32 bits of a __be64. */
static __be32 be64_get_low32(__be64 x)
{
#ifdef __BIG_ENDIAN
return (__force __be32)x;
#else
return (__force __be32)((__force u64)x >> 32);
#endif
}
static __be16 filter_tnl_flags(__be16 flags)
{
return flags & (TUNNEL_CSUM | TUNNEL_KEY);
}
static struct sk_buff *__build_header(struct sk_buff *skb,
int tunnel_hlen)
{
const struct ovs_key_ipv4_tunnel *tun_key = OVS_CB(skb)->tun_key;
struct tnl_ptk_info tpi;
skb = gre_handle_offloads(skb, !!(tun_key->tun_flags & TUNNEL_CSUM));
if (IS_ERR(skb))
return NULL;
tpi.flags = filter_tnl_flags(tun_key->tun_flags);
tpi.proto = htons(ETH_P_TEB);
tpi.key = be64_get_low32(tun_key->tun_id);
tpi.seq = 0;
gre_build_header(skb, &tpi, tunnel_hlen);
return skb;
}
static __be64 key_to_tunnel_id(__be32 key, __be32 seq)
{
#ifdef __BIG_ENDIAN
return (__force __be64)((__force u64)seq << 32 | (__force u32)key);
#else
return (__force __be64)((__force u64)key << 32 | (__force u32)seq);
#endif
}
/* Called with rcu_read_lock and BH disabled. */
static int gre_rcv(struct sk_buff *skb,
const struct tnl_ptk_info *tpi)
{
struct ovs_key_ipv4_tunnel tun_key;
struct ovs_net *ovs_net;
struct vport *vport;
__be64 key;
ovs_net = net_generic(dev_net(skb->dev), ovs_net_id);
vport = rcu_dereference(ovs_net->vport_net.gre_vport);
if (unlikely(!vport))
return PACKET_REJECT;
key = key_to_tunnel_id(tpi->key, tpi->seq);
ovs_flow_tun_key_init(&tun_key, ip_hdr(skb), key,
filter_tnl_flags(tpi->flags));
ovs_vport_receive(vport, skb, &tun_key);
return PACKET_RCVD;
}
static int gre_tnl_send(struct vport *vport, struct sk_buff *skb)
{
struct net *net = ovs_dp_get_net(vport->dp);
struct flowi4 fl;
struct rtable *rt;
int min_headroom;
int tunnel_hlen;
__be16 df;
int err;
if (unlikely(!OVS_CB(skb)->tun_key)) {
err = -EINVAL;
goto error;
}
/* Route lookup */
memset(&fl, 0, sizeof(fl));
fl.daddr = OVS_CB(skb)->tun_key->ipv4_dst;
fl.saddr = OVS_CB(skb)->tun_key->ipv4_src;
fl.flowi4_tos = RT_TOS(OVS_CB(skb)->tun_key->ipv4_tos);
fl.flowi4_mark = skb->mark;
fl.flowi4_proto = IPPROTO_GRE;
rt = ip_route_output_key(net, &fl);
if (IS_ERR(rt))
return PTR_ERR(rt);
tunnel_hlen = ip_gre_calc_hlen(OVS_CB(skb)->tun_key->tun_flags);
min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
+ tunnel_hlen + sizeof(struct iphdr)
+ (vlan_tx_tag_present(skb) ? VLAN_HLEN : 0);
if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) {
int head_delta = SKB_DATA_ALIGN(min_headroom -
skb_headroom(skb) +
16);
err = pskb_expand_head(skb, max_t(int, head_delta, 0),
0, GFP_ATOMIC);
if (unlikely(err))
goto err_free_rt;
}
if (vlan_tx_tag_present(skb)) {
if (unlikely(!__vlan_put_tag(skb,
skb->vlan_proto,
vlan_tx_tag_get(skb)))) {
err = -ENOMEM;
goto err_free_rt;
}
skb->vlan_tci = 0;
}
/* Push Tunnel header. */
skb = __build_header(skb, tunnel_hlen);
if (unlikely(!skb)) {
err = 0;
goto err_free_rt;
}
df = OVS_CB(skb)->tun_key->tun_flags & TUNNEL_DONT_FRAGMENT ?
htons(IP_DF) : 0;
skb->local_df = 1;
return iptunnel_xmit(net, rt, skb, fl.saddr,
OVS_CB(skb)->tun_key->ipv4_dst, IPPROTO_GRE,
OVS_CB(skb)->tun_key->ipv4_tos,
OVS_CB(skb)->tun_key->ipv4_ttl, df);
err_free_rt:
ip_rt_put(rt);
error:
return err;
}
static struct gre_cisco_protocol gre_protocol = {
.handler = gre_rcv,
.priority = 1,
};
static int gre_ports;
static int gre_init(void)
{
int err;
gre_ports++;
if (gre_ports > 1)
return 0;
err = gre_cisco_register(&gre_protocol);
if (err)
pr_warn("cannot register gre protocol handler\n");
return err;
}
static void gre_exit(void)
{
gre_ports--;
if (gre_ports > 0)
return;
gre_cisco_unregister(&gre_protocol);
}
static const char *gre_get_name(const struct vport *vport)
{
return vport_priv(vport);
}
static struct vport *gre_create(const struct vport_parms *parms)
{
struct net *net = ovs_dp_get_net(parms->dp);
struct ovs_net *ovs_net;
struct vport *vport;
int err;
err = gre_init();
if (err)
return ERR_PTR(err);
ovs_net = net_generic(net, ovs_net_id);
if (ovsl_dereference(ovs_net->vport_net.gre_vport)) {
vport = ERR_PTR(-EEXIST);
goto error;
}
vport = ovs_vport_alloc(IFNAMSIZ, &ovs_gre_vport_ops, parms);
if (IS_ERR(vport))
goto error;
strncpy(vport_priv(vport), parms->name, IFNAMSIZ);
rcu_assign_pointer(ovs_net->vport_net.gre_vport, vport);
return vport;
error:
gre_exit();
return vport;
}
static void gre_tnl_destroy(struct vport *vport)
{
struct net *net = ovs_dp_get_net(vport->dp);
struct ovs_net *ovs_net;
ovs_net = net_generic(net, ovs_net_id);
rcu_assign_pointer(ovs_net->vport_net.gre_vport, NULL);
ovs_vport_deferred_free(vport);
gre_exit();
}
const struct vport_ops ovs_gre_vport_ops = {
.type = OVS_VPORT_TYPE_GRE,
.create = gre_create,
.destroy = gre_tnl_destroy,
.get_name = gre_get_name,
.send = gre_tnl_send,
};
