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openvswitch: Use regular GRE net_device instead of vport
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Using GRE tunnel meta data collection feature, we can implement
OVS GRE vport. This patch removes all of the OVS
specific GRE code and make OVS use a ip_gre net_device.
Minimal GRE vport is kept to handle compatibility with
current userspace application.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Pravin B Shelar authored and David S. Miller committed Aug 10, 2015
1 parent 2e15ea3 commit b2acd1d
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Showing 5 changed files with 61 additions and 260 deletions.
12 changes: 2 additions & 10 deletions include/net/gre.h
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Original file line number Diff line number Diff line change
Expand Up @@ -33,16 +33,8 @@ struct gre_cisco_protocol {
int gre_cisco_register(struct gre_cisco_protocol *proto);
int gre_cisco_unregister(struct gre_cisco_protocol *proto);

void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
int hdr_len);

static inline struct sk_buff *gre_handle_offloads(struct sk_buff *skb,
bool csum)
{
return iptunnel_handle_offloads(skb, csum,
csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE);
}

struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
u8 name_assign_type);

static inline int ip_gre_calc_hlen(__be16 o_flags)
{
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34 changes: 0 additions & 34 deletions net/ipv4/gre_demux.c
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Original file line number Diff line number Diff line change
Expand Up @@ -61,40 +61,6 @@ int gre_del_protocol(const struct gre_protocol *proto, u8 version)
}
EXPORT_SYMBOL_GPL(gre_del_protocol);

void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
int hdr_len)
{
struct gre_base_hdr *greh;

skb_push(skb, hdr_len);

skb_reset_transport_header(skb);
greh = (struct gre_base_hdr *)skb->data;
greh->flags = tnl_flags_to_gre_flags(tpi->flags);
greh->protocol = tpi->proto;

if (tpi->flags&(TUNNEL_KEY|TUNNEL_CSUM|TUNNEL_SEQ)) {
__be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);

if (tpi->flags&TUNNEL_SEQ) {
*ptr = tpi->seq;
ptr--;
}
if (tpi->flags&TUNNEL_KEY) {
*ptr = tpi->key;
ptr--;
}
if (tpi->flags&TUNNEL_CSUM &&
!(skb_shinfo(skb)->gso_type &
(SKB_GSO_GRE|SKB_GSO_GRE_CSUM))) {
*ptr = 0;
*(__sum16 *)ptr = csum_fold(skb_checksum(skb, 0,
skb->len, 0));
}
}
}
EXPORT_SYMBOL_GPL(gre_build_header);

static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
bool *csum_err)
{
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36 changes: 36 additions & 0 deletions net/ipv4/ip_gre.c
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Original file line number Diff line number Diff line change
Expand Up @@ -318,6 +318,13 @@ static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
ip_tunnel_xmit(skb, dev, tnl_params, tnl_params->protocol);
}

static struct sk_buff *gre_handle_offloads(struct sk_buff *skb,
bool csum)
{
return iptunnel_handle_offloads(skb, csum,
csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE);
}

static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ip_tunnel_info *tun_info;
Expand Down Expand Up @@ -1012,6 +1019,35 @@ static struct rtnl_link_ops ipgre_tap_ops __read_mostly = {
.get_link_net = ip_tunnel_get_link_net,
};

struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
u8 name_assign_type)
{
struct nlattr *tb[IFLA_MAX + 1];
struct net_device *dev;
struct ip_tunnel *t;
int err;

memset(&tb, 0, sizeof(tb));

dev = rtnl_create_link(net, name, name_assign_type,
&ipgre_tap_ops, tb);
if (IS_ERR(dev))
return dev;

/* Configure flow based GRE device. */
t = netdev_priv(dev);
t->collect_md = true;

err = ipgre_newlink(net, dev, tb, NULL);
if (err < 0)
goto out;
return dev;
out:
free_netdev(dev);
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(gretap_fb_dev_create);

static int __net_init ipgre_tap_init_net(struct net *net)
{
return ip_tunnel_init_net(net, gre_tap_net_id, &ipgre_tap_ops, "gretap0");
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2 changes: 1 addition & 1 deletion net/openvswitch/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -34,7 +34,7 @@ config OPENVSWITCH
config OPENVSWITCH_GRE
tristate "Open vSwitch GRE tunneling support"
depends on OPENVSWITCH
depends on NET_IPGRE_DEMUX
depends on NET_IPGRE
default OPENVSWITCH
---help---
If you say Y here, then the Open vSwitch will be able create GRE
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237 changes: 22 additions & 215 deletions net/openvswitch/vport-gre.c
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Original file line number Diff line number Diff line change
Expand Up @@ -45,235 +45,43 @@

#include "datapath.h"
#include "vport.h"
#include "vport-netdev.h"

static struct vport_ops ovs_gre_vport_ops;

/* Returns the least-significant 32 bits of a __be64. */
static __be32 be64_get_low32(__be64 x)
static struct vport *gre_tnl_create(const struct vport_parms *parms)
{
#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)
{
struct tnl_ptk_info tpi;
const struct ip_tunnel_key *tun_key;

tun_key = &OVS_CB(skb)->egress_tun_info->key;

skb = gre_handle_offloads(skb, !!(tun_key->tun_flags & TUNNEL_CSUM));
if (IS_ERR(skb))
return skb;

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 ip_tunnel_info tun_info;
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);
ip_tunnel_info_init(&tun_info, ip_hdr(skb), 0, 0, key,
filter_tnl_flags(tpi->flags), NULL, 0);

ovs_vport_receive(vport, skb, &tun_info);
return PACKET_RCVD;
}

/* Called with rcu_read_lock and BH disabled. */
static int gre_err(struct sk_buff *skb, u32 info,
const struct tnl_ptk_info *tpi)
{
struct ovs_net *ovs_net;
struct net *net = ovs_dp_get_net(parms->dp);
struct net_device *dev;
struct vport *vport;

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;
else
return PACKET_RCVD;
}

static int gre_tnl_send(struct vport *vport, struct sk_buff *skb)
{
struct net *net = ovs_dp_get_net(vport->dp);
const struct ip_tunnel_key *tun_key;
struct flowi4 fl;
struct rtable *rt;
int min_headroom;
int tunnel_hlen;
__be16 df;
int err;

if (unlikely(!OVS_CB(skb)->egress_tun_info)) {
err = -EINVAL;
goto err_free_skb;
}

tun_key = &OVS_CB(skb)->egress_tun_info->key;
rt = ovs_tunnel_route_lookup(net, tun_key, skb->mark, &fl, IPPROTO_GRE);
if (IS_ERR(rt)) {
err = PTR_ERR(rt);
goto err_free_skb;
}

tunnel_hlen = ip_gre_calc_hlen(tun_key->tun_flags);

min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
+ tunnel_hlen + sizeof(struct iphdr)
+ (skb_vlan_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;
}

skb = vlan_hwaccel_push_inside(skb);
if (unlikely(!skb)) {
err = -ENOMEM;
goto err_free_rt;
}

/* Push Tunnel header. */
skb = __build_header(skb, tunnel_hlen);
if (IS_ERR(skb)) {
err = PTR_ERR(skb);
skb = NULL;
goto err_free_rt;
vport = ovs_vport_alloc(0, &ovs_gre_vport_ops, parms);
if (IS_ERR(vport))
return vport;

rtnl_lock();
dev = gretap_fb_dev_create(net, parms->name, NET_NAME_USER);
if (IS_ERR(dev)) {
rtnl_unlock();
ovs_vport_free(vport);
return ERR_CAST(dev);
}

df = tun_key->tun_flags & TUNNEL_DONT_FRAGMENT ?
htons(IP_DF) : 0;

skb->ignore_df = 1;

return iptunnel_xmit(skb->sk, rt, skb, fl.saddr,
tun_key->ipv4_dst, IPPROTO_GRE,
tun_key->ipv4_tos, tun_key->ipv4_ttl, df, false);
err_free_rt:
ip_rt_put(rt);
err_free_skb:
kfree_skb(skb);
return err;
}

static struct gre_cisco_protocol gre_protocol = {
.handler = gre_rcv,
.err_handler = gre_err,
.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);
}
dev_change_flags(dev, dev->flags | IFF_UP);
rtnl_unlock();

static const char *gre_get_name(const struct vport *vport)
{
return vport_priv(vport);
return 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);
vport = gre_tnl_create(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);
return vport;

RCU_INIT_POINTER(ovs_net->vport_net.gre_vport, NULL);
ovs_vport_deferred_free(vport);
gre_exit();
return ovs_netdev_link(vport, parms->name);
}

static int gre_get_egress_tun_info(struct vport *vport, struct sk_buff *skb,
Expand All @@ -288,10 +96,9 @@ static int gre_get_egress_tun_info(struct vport *vport, struct sk_buff *skb,
static 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,
.send = ovs_netdev_send,
.get_egress_tun_info = gre_get_egress_tun_info,
.destroy = ovs_netdev_tunnel_destroy,
.owner = THIS_MODULE,
};

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