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300 lines
6.3 KiB
300 lines
6.3 KiB
/*
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* xfrm_output.c - Common IPsec encapsulation code.
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*
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* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
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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/netfilter.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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static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb);
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static int xfrm_skb_check_space(struct sk_buff *skb)
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{
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struct dst_entry *dst = skb_dst(skb);
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int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev)
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- skb_headroom(skb);
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int ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
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if (nhead <= 0) {
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if (ntail <= 0)
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return 0;
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nhead = 0;
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} else if (ntail < 0)
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ntail = 0;
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return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
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}
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/* Children define the path of the packet through the
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* Linux networking. Thus, destinations are stackable.
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*/
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static struct dst_entry *skb_dst_pop(struct sk_buff *skb)
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{
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struct dst_entry *child = dst_clone(skb_dst(skb)->child);
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skb_dst_drop(skb);
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return child;
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}
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static int xfrm_output_one(struct sk_buff *skb, int err)
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{
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struct dst_entry *dst = skb_dst(skb);
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struct xfrm_state *x = dst->xfrm;
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struct net *net = xs_net(x);
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if (err <= 0)
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goto resume;
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do {
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err = xfrm_skb_check_space(skb);
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if (err) {
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XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
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goto error_nolock;
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}
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skb->mark = xfrm_smark_get(skb->mark, x);
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err = x->outer_mode->output(x, skb);
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if (err) {
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XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
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goto error_nolock;
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}
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spin_lock_bh(&x->lock);
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if (unlikely(x->km.state != XFRM_STATE_VALID)) {
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XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
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err = -EINVAL;
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goto error;
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}
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err = xfrm_state_check_expire(x);
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if (err) {
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XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
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goto error;
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}
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err = x->repl->overflow(x, skb);
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if (err) {
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XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
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goto error;
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}
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x->curlft.bytes += skb->len;
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x->curlft.packets++;
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spin_unlock_bh(&x->lock);
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skb_dst_force(skb);
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if (!skb_dst(skb)) {
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XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
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err = -EHOSTUNREACH;
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goto error_nolock;
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}
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if (xfrm_offload(skb)) {
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x->type_offload->encap(x, skb);
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} else {
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/* Inner headers are invalid now. */
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skb->encapsulation = 0;
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err = x->type->output(x, skb);
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if (err == -EINPROGRESS)
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goto out;
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}
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resume:
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if (err) {
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XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
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goto error_nolock;
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}
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dst = skb_dst_pop(skb);
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if (!dst) {
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XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
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err = -EHOSTUNREACH;
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goto error_nolock;
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}
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skb_dst_set(skb, dst);
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x = dst->xfrm;
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} while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL));
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return 0;
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error:
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spin_unlock_bh(&x->lock);
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error_nolock:
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kfree_skb(skb);
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out:
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return err;
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}
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int xfrm_output_resume(struct sk_buff *skb, int err)
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{
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struct net *net = xs_net(skb_dst(skb)->xfrm);
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while (likely((err = xfrm_output_one(skb, err)) == 0)) {
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nf_reset(skb);
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err = skb_dst(skb)->ops->local_out(net, skb->sk, skb);
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if (unlikely(err != 1))
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goto out;
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if (!skb_dst(skb)->xfrm)
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return dst_output(net, skb->sk, skb);
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err = nf_hook(skb_dst(skb)->ops->family,
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NF_INET_POST_ROUTING, net, skb->sk, skb,
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NULL, skb_dst(skb)->dev, xfrm_output2);
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if (unlikely(err != 1))
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goto out;
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}
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if (err == -EINPROGRESS)
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err = 0;
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out:
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return err;
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}
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EXPORT_SYMBOL_GPL(xfrm_output_resume);
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static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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return xfrm_output_resume(skb, 1);
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}
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static int xfrm_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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struct sk_buff *segs;
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BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_SGO_CB_OFFSET);
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BUILD_BUG_ON(sizeof(*IP6CB(skb)) > SKB_SGO_CB_OFFSET);
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segs = skb_gso_segment(skb, 0);
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kfree_skb(skb);
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if (IS_ERR(segs))
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return PTR_ERR(segs);
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if (segs == NULL)
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return -EINVAL;
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do {
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struct sk_buff *nskb = segs->next;
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int err;
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segs->next = NULL;
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err = xfrm_output2(net, sk, segs);
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if (unlikely(err)) {
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kfree_skb_list(nskb);
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return err;
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}
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segs = nskb;
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} while (segs);
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return 0;
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}
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int xfrm_output(struct sock *sk, struct sk_buff *skb)
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{
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struct net *net = dev_net(skb_dst(skb)->dev);
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struct xfrm_state *x = skb_dst(skb)->xfrm;
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int err;
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secpath_reset(skb);
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if (xfrm_dev_offload_ok(skb, x)) {
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struct sec_path *sp;
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sp = secpath_dup(skb->sp);
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if (!sp) {
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XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
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kfree_skb(skb);
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return -ENOMEM;
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}
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if (skb->sp)
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secpath_put(skb->sp);
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skb->sp = sp;
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skb->encapsulation = 1;
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sp->olen++;
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sp->xvec[skb->sp->len++] = x;
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xfrm_state_hold(x);
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if (skb_is_gso(skb)) {
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if (skb->inner_protocol)
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return xfrm_output_gso(net, sk, skb);
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skb_shinfo(skb)->gso_type |= SKB_GSO_ESP;
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goto out;
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}
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if (x->xso.dev && x->xso.dev->features & NETIF_F_HW_ESP_TX_CSUM)
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goto out;
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} else {
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if (skb_is_gso(skb))
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return xfrm_output_gso(net, sk, skb);
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}
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if (skb->ip_summed == CHECKSUM_PARTIAL) {
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err = skb_checksum_help(skb);
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if (err) {
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XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
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kfree_skb(skb);
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return err;
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}
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}
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out:
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return xfrm_output2(net, sk, skb);
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}
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EXPORT_SYMBOL_GPL(xfrm_output);
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int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
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{
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struct xfrm_mode *inner_mode;
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if (x->sel.family == AF_UNSPEC)
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inner_mode = xfrm_ip2inner_mode(x,
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xfrm_af2proto(skb_dst(skb)->ops->family));
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else
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inner_mode = x->inner_mode;
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if (inner_mode == NULL)
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return -EAFNOSUPPORT;
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return inner_mode->afinfo->extract_output(x, skb);
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}
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EXPORT_SYMBOL_GPL(xfrm_inner_extract_output);
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void xfrm_local_error(struct sk_buff *skb, int mtu)
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{
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unsigned int proto;
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struct xfrm_state_afinfo *afinfo;
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if (skb->protocol == htons(ETH_P_IP))
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proto = AF_INET;
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else if (skb->protocol == htons(ETH_P_IPV6) &&
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skb->sk->sk_family == AF_INET6)
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proto = AF_INET6;
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else
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return;
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afinfo = xfrm_state_get_afinfo(proto);
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if (afinfo) {
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afinfo->local_error(skb, mtu);
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rcu_read_unlock();
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}
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}
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EXPORT_SYMBOL_GPL(xfrm_local_error);
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