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/*
* 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
*/
#include <linux/version.h>
#if LINUX_VERSION_CODE < KERNEL_VERSION(3,16,0)
#include <linux/module.h>
#include <linux/if.h>
#include <linux/if_tunnel.h>
#include <linux/if_vlan.h>
#include <linux/icmp.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <net/gre.h>
#include <net/icmp.h>
#include <net/protocol.h>
#include <net/route.h>
#include <net/xfrm.h>
#include "gso.h"
#include "mpls.h"
#include "vlan.h"
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,37) && \
!defined(HAVE_VLAN_BUG_WORKAROUND)
#include <linux/module.h>
static int vlan_tso __read_mostly;
module_param(vlan_tso, int, 0644);
MODULE_PARM_DESC(vlan_tso, "Enable TSO for VLAN packets");
#else
#define vlan_tso true
#endif
static bool dev_supports_vlan_tx(struct net_device *dev)
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,37)
return true;
#elif defined(HAVE_VLAN_BUG_WORKAROUND)
return dev->features & NETIF_F_HW_VLAN_TX;
#else
/* Assume that the driver is buggy. */
return false;
#endif
}
/* Strictly this is not needed and will be optimised out
* as this code is guarded by if LINUX_VERSION_CODE < KERNEL_VERSION(3,16,0).
* It is here to make things explicit should the compatibility
* code be extended in some way prior extending its life-span
* beyond v3.16.
*/
static bool supports_mpls_gso(void)
{
/* MPLS GSO was introduced in v3.11, however it was not correctly
* activated using mpls_features until v3.16. */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,16,0)
return true;
#else
return false;
#endif
}
int rpl_dev_queue_xmit(struct sk_buff *skb)
{
#undef dev_queue_xmit
int err = -ENOMEM;
bool vlan, mpls;
vlan = mpls = false;
/* Avoid traversing any VLAN tags that are present to determine if
* the ethtype is MPLS. Instead compare the mac_len (end of L2) and
* skb_network_offset() (beginning of L3) whose inequality will
* indicate the presence of an MPLS label stack. */
if (skb->mac_len != skb_network_offset(skb) && !supports_mpls_gso())
mpls = true;
if (vlan_tx_tag_present(skb) && !dev_supports_vlan_tx(skb->dev))
vlan = true;
if (vlan || mpls) {
int features;
features = netif_skb_features(skb);
if (vlan) {
if (!vlan_tso)
features &= ~(NETIF_F_TSO | NETIF_F_TSO6 |
NETIF_F_UFO | NETIF_F_FSO);
skb = __vlan_put_tag(skb, skb->vlan_proto,
vlan_tx_tag_get(skb));
if (unlikely(!skb))
return err;
vlan_set_tci(skb, 0);
}
/* As of v3.11 the kernel provides an mpls_features field in
* struct net_device which allows devices to advertise which
* features its supports for MPLS. This value defaults to
* NETIF_F_SG and as of v3.16.
*
* This compatibility code is intended for kernels older
* than v3.16 that do not support MPLS GSO and do not
* use mpls_features. Thus this code uses NETIF_F_SG
* directly in place of mpls_features.
*/
if (mpls)
features &= NETIF_F_SG;
if (netif_needs_gso(skb, features)) {
struct sk_buff *nskb;
nskb = skb_gso_segment(skb, features);
if (!nskb) {
if (unlikely(skb_cloned(skb) &&
pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
goto drop;
skb_shinfo(skb)->gso_type &= ~SKB_GSO_DODGY;
goto xmit;
}
if (IS_ERR(nskb)) {
err = PTR_ERR(nskb);
goto drop;
}
consume_skb(skb);
skb = nskb;
do {
nskb = skb->next;
skb->next = NULL;
err = dev_queue_xmit(skb);
skb = nskb;
} while (skb);
return err;
}
}
xmit:
return dev_queue_xmit(skb);
drop:
kfree_skb(skb);
return err;
}
static __be16 __skb_network_protocol(struct sk_buff *skb)
{
__be16 type = skb->protocol;
int vlan_depth = ETH_HLEN;
while (type == htons(ETH_P_8021Q) || type == htons(ETH_P_8021AD)) {
struct vlan_hdr *vh;
if (unlikely(!pskb_may_pull(skb, vlan_depth + VLAN_HLEN)))
return 0;
vh = (struct vlan_hdr *)(skb->data + vlan_depth);
type = vh->h_vlan_encapsulated_proto;
vlan_depth += VLAN_HLEN;
}
if (eth_p_mpls(type))
type = ovs_skb_get_inner_protocol(skb);
return type;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(3,12,0)
static void tnl_fix_segment(struct sk_buff *skb)
{
if (OVS_GSO_CB(skb)->fix_segment)
OVS_GSO_CB(skb)->fix_segment(skb);
}
#else
static void tnl_fix_segment(struct sk_buff *skb) { }
#endif
static struct sk_buff *tnl_skb_gso_segment(struct sk_buff *skb,
netdev_features_t features,
bool tx_path)
{
struct iphdr *iph = ip_hdr(skb);
int pkt_hlen = skb_inner_network_offset(skb); /* inner l2 + tunnel hdr. */
int mac_offset = skb_inner_mac_offset(skb);
struct sk_buff *skb1 = skb;
struct sk_buff *segs;
__be16 proto = skb->protocol;
char cb[sizeof(skb->cb)];
/* setup whole inner packet to get protocol. */
__skb_pull(skb, mac_offset);
skb->protocol = __skb_network_protocol(skb);
/* setup l3 packet to gso, to get around segmentation bug on older kernel.*/
__skb_pull(skb, (pkt_hlen - mac_offset));
skb_reset_mac_header(skb);
skb_reset_network_header(skb);
skb_reset_transport_header(skb);
/* From 3.9 kernel skb->cb is used by skb gso. Therefore
* make copy of it to restore it back. */
memcpy(cb, skb->cb, sizeof(cb));
segs = __skb_gso_segment(skb, 0, tx_path);
if (!segs || IS_ERR(segs))
goto free;
skb = segs;
while (skb) {
__skb_push(skb, pkt_hlen);
skb_reset_mac_header(skb);
skb_reset_network_header(skb);
skb_set_transport_header(skb, sizeof(struct iphdr));
skb->mac_len = 0;
memcpy(ip_hdr(skb), iph, pkt_hlen);
memcpy(skb->cb, cb, sizeof(cb));
tnl_fix_segment(skb);
skb->protocol = proto;
skb = skb->next;
}
free:
consume_skb(skb1);
return segs;
}
int rpl_ip_local_out(struct sk_buff *skb)
{
int ret = NETDEV_TX_OK;
int id = -1;
if (skb_is_gso(skb)) {
struct iphdr *iph;
iph = ip_hdr(skb);
id = ntohs(iph->id);
skb = tnl_skb_gso_segment(skb, 0, false);
if (!skb || IS_ERR(skb))
return 0;
} else if (skb->ip_summed == CHECKSUM_PARTIAL) {
int err;
err = skb_checksum_help(skb);
if (unlikely(err))
return 0;
}
while (skb) {
struct sk_buff *next_skb = skb->next;
struct iphdr *iph;
int err;
skb->next = NULL;
iph = ip_hdr(skb);
if (id >= 0)
iph->id = htons(id++);
memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
#undef ip_local_out
err = ip_local_out(skb);
if (unlikely(net_xmit_eval(err)))
ret = err;
skb = next_skb;
}
return ret;
}
#endif /* 3.16 */
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