![Daniel Axtens](/assets/img/avatar_default.png)
If you take a GSO skb, and split it into packets, will the network length (L3 headers + L4 headers + payload) of those packets be small enough to fit within a given MTU? skb_gso_validate_mtu gives you the answer to that question. However, we recently added to add a way to validate the MAC length of a split GSO skb (L2+L3+L4+payload), and the names get confusing, so rename skb_gso_validate_mtu to skb_gso_validate_network_len Signed-off-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
357 lines
7.6 KiB
C
357 lines
7.6 KiB
C
/*
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* xfrm_device.c - IPsec device offloading code.
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*
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* Copyright (c) 2015 secunet Security Networks AG
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*
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* Author:
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* Steffen Klassert <steffen.klassert@secunet.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/errno.h>
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#include <linux/module.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <net/dst.h>
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#include <net/xfrm.h>
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#include <linux/notifier.h>
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#ifdef CONFIG_XFRM_OFFLOAD
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struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t features, bool *again)
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{
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int err;
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unsigned long flags;
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struct xfrm_state *x;
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struct sk_buff *skb2;
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struct softnet_data *sd;
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netdev_features_t esp_features = features;
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struct xfrm_offload *xo = xfrm_offload(skb);
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if (!xo)
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return skb;
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if (!(features & NETIF_F_HW_ESP))
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esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
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x = skb->sp->xvec[skb->sp->len - 1];
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if (xo->flags & XFRM_GRO || x->xso.flags & XFRM_OFFLOAD_INBOUND)
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return skb;
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local_irq_save(flags);
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sd = this_cpu_ptr(&softnet_data);
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err = !skb_queue_empty(&sd->xfrm_backlog);
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local_irq_restore(flags);
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if (err) {
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*again = true;
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return skb;
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}
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if (skb_is_gso(skb)) {
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struct net_device *dev = skb->dev;
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if (unlikely(!x->xso.offload_handle || (x->xso.dev != dev))) {
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struct sk_buff *segs;
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/* Packet got rerouted, fixup features and segment it. */
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esp_features = esp_features & ~(NETIF_F_HW_ESP
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| NETIF_F_GSO_ESP);
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segs = skb_gso_segment(skb, esp_features);
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if (IS_ERR(segs)) {
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kfree_skb(skb);
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atomic_long_inc(&dev->tx_dropped);
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return NULL;
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} else {
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consume_skb(skb);
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skb = segs;
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}
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}
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}
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if (!skb->next) {
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x->outer_mode->xmit(x, skb);
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xo->flags |= XFRM_DEV_RESUME;
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err = x->type_offload->xmit(x, skb, esp_features);
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if (err) {
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if (err == -EINPROGRESS)
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return NULL;
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XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
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kfree_skb(skb);
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return NULL;
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}
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skb_push(skb, skb->data - skb_mac_header(skb));
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return skb;
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}
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skb2 = skb;
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do {
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struct sk_buff *nskb = skb2->next;
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skb2->next = NULL;
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xo = xfrm_offload(skb2);
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xo->flags |= XFRM_DEV_RESUME;
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x->outer_mode->xmit(x, skb2);
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err = x->type_offload->xmit(x, skb2, esp_features);
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if (!err) {
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skb2->next = nskb;
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} else if (err != -EINPROGRESS) {
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XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
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skb2->next = nskb;
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kfree_skb_list(skb2);
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return NULL;
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} else {
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if (skb == skb2)
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skb = nskb;
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if (!skb)
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return NULL;
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goto skip_push;
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}
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skb_push(skb2, skb2->data - skb_mac_header(skb2));
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skip_push:
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skb2 = nskb;
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} while (skb2);
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return skb;
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}
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EXPORT_SYMBOL_GPL(validate_xmit_xfrm);
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int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
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struct xfrm_user_offload *xuo)
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{
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int err;
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struct dst_entry *dst;
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struct net_device *dev;
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struct xfrm_state_offload *xso = &x->xso;
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xfrm_address_t *saddr;
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xfrm_address_t *daddr;
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if (!x->type_offload)
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return -EINVAL;
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/* We don't yet support UDP encapsulation and TFC padding. */
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if (x->encap || x->tfcpad)
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return -EINVAL;
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dev = dev_get_by_index(net, xuo->ifindex);
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if (!dev) {
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if (!(xuo->flags & XFRM_OFFLOAD_INBOUND)) {
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saddr = &x->props.saddr;
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daddr = &x->id.daddr;
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} else {
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saddr = &x->id.daddr;
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daddr = &x->props.saddr;
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}
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dst = __xfrm_dst_lookup(net, 0, 0, saddr, daddr,
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x->props.family, x->props.output_mark);
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if (IS_ERR(dst))
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return 0;
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dev = dst->dev;
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dev_hold(dev);
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dst_release(dst);
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}
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if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_state_add) {
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xso->dev = NULL;
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dev_put(dev);
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return 0;
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}
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if (x->props.flags & XFRM_STATE_ESN &&
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!dev->xfrmdev_ops->xdo_dev_state_advance_esn) {
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xso->dev = NULL;
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dev_put(dev);
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return -EINVAL;
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}
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xso->dev = dev;
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xso->num_exthdrs = 1;
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xso->flags = xuo->flags;
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err = dev->xfrmdev_ops->xdo_dev_state_add(x);
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if (err) {
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xso->dev = NULL;
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dev_put(dev);
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return err;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(xfrm_dev_state_add);
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bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
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{
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int mtu;
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struct dst_entry *dst = skb_dst(skb);
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struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
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struct net_device *dev = x->xso.dev;
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if (!x->type_offload || x->encap)
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return false;
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if ((!dev || (x->xso.offload_handle && (dev == xfrm_dst_path(dst)->dev))) &&
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(!xdst->child->xfrm && x->type->get_mtu)) {
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mtu = x->type->get_mtu(x, xdst->child_mtu_cached);
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if (skb->len <= mtu)
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goto ok;
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if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
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goto ok;
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}
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return false;
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ok:
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if (dev && dev->xfrmdev_ops && dev->xfrmdev_ops->xdo_dev_offload_ok)
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return x->xso.dev->xfrmdev_ops->xdo_dev_offload_ok(skb, x);
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return true;
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}
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EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);
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void xfrm_dev_resume(struct sk_buff *skb)
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{
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struct net_device *dev = skb->dev;
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int ret = NETDEV_TX_BUSY;
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struct netdev_queue *txq;
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struct softnet_data *sd;
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unsigned long flags;
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rcu_read_lock();
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txq = netdev_pick_tx(dev, skb, NULL);
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HARD_TX_LOCK(dev, txq, smp_processor_id());
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if (!netif_xmit_frozen_or_stopped(txq))
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skb = dev_hard_start_xmit(skb, dev, txq, &ret);
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HARD_TX_UNLOCK(dev, txq);
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if (!dev_xmit_complete(ret)) {
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local_irq_save(flags);
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sd = this_cpu_ptr(&softnet_data);
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skb_queue_tail(&sd->xfrm_backlog, skb);
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raise_softirq_irqoff(NET_TX_SOFTIRQ);
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local_irq_restore(flags);
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}
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rcu_read_unlock();
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}
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EXPORT_SYMBOL_GPL(xfrm_dev_resume);
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void xfrm_dev_backlog(struct softnet_data *sd)
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{
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struct sk_buff_head *xfrm_backlog = &sd->xfrm_backlog;
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struct sk_buff_head list;
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struct sk_buff *skb;
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if (skb_queue_empty(xfrm_backlog))
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return;
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__skb_queue_head_init(&list);
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spin_lock(&xfrm_backlog->lock);
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skb_queue_splice_init(xfrm_backlog, &list);
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spin_unlock(&xfrm_backlog->lock);
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while (!skb_queue_empty(&list)) {
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skb = __skb_dequeue(&list);
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xfrm_dev_resume(skb);
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}
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}
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#endif
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static int xfrm_api_check(struct net_device *dev)
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{
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#ifdef CONFIG_XFRM_OFFLOAD
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if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
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!(dev->features & NETIF_F_HW_ESP))
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return NOTIFY_BAD;
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if ((dev->features & NETIF_F_HW_ESP) &&
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(!(dev->xfrmdev_ops &&
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dev->xfrmdev_ops->xdo_dev_state_add &&
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dev->xfrmdev_ops->xdo_dev_state_delete)))
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return NOTIFY_BAD;
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#else
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if (dev->features & (NETIF_F_HW_ESP | NETIF_F_HW_ESP_TX_CSUM))
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return NOTIFY_BAD;
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#endif
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return NOTIFY_DONE;
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}
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static int xfrm_dev_register(struct net_device *dev)
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{
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return xfrm_api_check(dev);
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}
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static int xfrm_dev_unregister(struct net_device *dev)
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{
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xfrm_policy_cache_flush();
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return NOTIFY_DONE;
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}
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static int xfrm_dev_feat_change(struct net_device *dev)
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{
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return xfrm_api_check(dev);
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}
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static int xfrm_dev_down(struct net_device *dev)
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{
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if (dev->features & NETIF_F_HW_ESP)
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xfrm_dev_state_flush(dev_net(dev), dev, true);
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xfrm_policy_cache_flush();
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return NOTIFY_DONE;
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}
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static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
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{
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struct net_device *dev = netdev_notifier_info_to_dev(ptr);
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switch (event) {
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case NETDEV_REGISTER:
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return xfrm_dev_register(dev);
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case NETDEV_UNREGISTER:
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return xfrm_dev_unregister(dev);
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case NETDEV_FEAT_CHANGE:
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return xfrm_dev_feat_change(dev);
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case NETDEV_DOWN:
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return xfrm_dev_down(dev);
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}
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return NOTIFY_DONE;
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}
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static struct notifier_block xfrm_dev_notifier = {
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.notifier_call = xfrm_dev_event,
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};
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void __net_init xfrm_dev_init(void)
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{
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register_netdevice_notifier(&xfrm_dev_notifier);
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}
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