skbuff.c (e700ac213a0f793fb4f83098413303e3dd080892) skbuff.c (7f678def99d29c520418607509bb19c7fc96a6db)
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Routines having to do with the 'struct sk_buff' memory handlers.
4 *
5 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
6 * Florian La Roche <rzsfl@rz.uni-sb.de>
7 *
8 * Fixes:

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75#include <linux/uaccess.h>
76#include <trace/events/skb.h>
77#include <linux/highmem.h>
78#include <linux/capability.h>
79#include <linux/user_namespace.h>
80#include <linux/indirect_call_wrapper.h>
81
82#include "datagram.h"
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Routines having to do with the 'struct sk_buff' memory handlers.
4 *
5 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
6 * Florian La Roche <rzsfl@rz.uni-sb.de>
7 *
8 * Fixes:

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75#include <linux/uaccess.h>
76#include <trace/events/skb.h>
77#include <linux/highmem.h>
78#include <linux/capability.h>
79#include <linux/user_namespace.h>
80#include <linux/indirect_call_wrapper.h>
81
82#include "datagram.h"
83#include "sock_destructor.h"
83
84struct kmem_cache *skbuff_head_cache __ro_after_init;
85static struct kmem_cache *skbuff_fclone_cache __ro_after_init;
86#ifdef CONFIG_SKB_EXTENSIONS
87static struct kmem_cache *skbuff_ext_cache __ro_after_init;
88#endif
89int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS;
90EXPORT_SYMBOL(sysctl_max_skb_frags);

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1799 * and frees original skb in case of failures.
1800 *
1801 * It expect increased headroom and generates warning otherwise.
1802 */
1803
1804struct sk_buff *skb_expand_head(struct sk_buff *skb, unsigned int headroom)
1805{
1806 int delta = headroom - skb_headroom(skb);
84
85struct kmem_cache *skbuff_head_cache __ro_after_init;
86static struct kmem_cache *skbuff_fclone_cache __ro_after_init;
87#ifdef CONFIG_SKB_EXTENSIONS
88static struct kmem_cache *skbuff_ext_cache __ro_after_init;
89#endif
90int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS;
91EXPORT_SYMBOL(sysctl_max_skb_frags);

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1800 * and frees original skb in case of failures.
1801 *
1802 * It expect increased headroom and generates warning otherwise.
1803 */
1804
1805struct sk_buff *skb_expand_head(struct sk_buff *skb, unsigned int headroom)
1806{
1807 int delta = headroom - skb_headroom(skb);
1808 int osize = skb_end_offset(skb);
1809 struct sock *sk = skb->sk;
1807
1808 if (WARN_ONCE(delta <= 0,
1809 "%s is expecting an increase in the headroom", __func__))
1810 return skb;
1811
1810
1811 if (WARN_ONCE(delta <= 0,
1812 "%s is expecting an increase in the headroom", __func__))
1813 return skb;
1814
1812 /* pskb_expand_head() might crash, if skb is shared */
1813 if (skb_shared(skb)) {
1815 delta = SKB_DATA_ALIGN(delta);
1816 /* pskb_expand_head() might crash, if skb is shared. */
1817 if (skb_shared(skb) || !is_skb_wmem(skb)) {
1814 struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
1815
1818 struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
1819
1816 if (likely(nskb)) {
1817 if (skb->sk)
1818 skb_set_owner_w(nskb, skb->sk);
1819 consume_skb(skb);
1820 } else {
1821 kfree_skb(skb);
1822 }
1820 if (unlikely(!nskb))
1821 goto fail;
1822
1823 if (sk)
1824 skb_set_owner_w(nskb, sk);
1825 consume_skb(skb);
1823 skb = nskb;
1824 }
1826 skb = nskb;
1827 }
1825 if (skb &&
1826 pskb_expand_head(skb, SKB_DATA_ALIGN(delta), 0, GFP_ATOMIC)) {
1827 kfree_skb(skb);
1828 skb = NULL;
1828 if (pskb_expand_head(skb, delta, 0, GFP_ATOMIC))
1829 goto fail;
1830
1831 if (sk && is_skb_wmem(skb)) {
1832 delta = skb_end_offset(skb) - osize;
1833 refcount_add(delta, &sk->sk_wmem_alloc);
1834 skb->truesize += delta;
1829 }
1830 return skb;
1835 }
1836 return skb;
1837
1838fail:
1839 kfree_skb(skb);
1840 return NULL;
1831}
1832EXPORT_SYMBOL(skb_expand_head);
1833
1834/**
1835 * skb_copy_expand - copy and expand sk_buff
1836 * @skb: buffer to copy
1837 * @newheadroom: new free bytes at head
1838 * @newtailroom: new free bytes at tail

--- 4724 unchanged lines hidden --- 		1841}
1842EXPORT_SYMBOL(skb_expand_head);
1843
1844/**
1845 * skb_copy_expand - copy and expand sk_buff
1846 * @skb: buffer to copy
1847 * @newheadroom: new free bytes at head
1848 * @newtailroom: new free bytes at tail

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