--- /dev/null
+/*
+ * Routines having to do with the 'struct sk_buff' memory handlers.
+ *
+ * Authors: Alan Cox <iiitac@pyr.swan.ac.uk>
+ * Florian La Roche <rzsfl@rz.uni-sb.de>
+ *
+ * Version: $Id: skbuff.c,v 1.90 2001/11/07 05:56:19 davem Exp $
+ *
+ * Fixes:
+ * Alan Cox : Fixed the worst of the load balancer bugs.
+ * Dave Platt : Interrupt stacking fix.
+ * Richard Kooijman : Timestamp fixes.
+ * Alan Cox : Changed buffer format.
+ * Alan Cox : destructor hook for AF_UNIX etc.
+ * Linus Torvalds : Better skb_clone.
+ * Alan Cox : Added skb_copy.
+ * Alan Cox : Added all the changed routines Linus
+ * only put in the headers
+ * Ray VanTassle : Fixed --skb->lock in free
+ * Alan Cox : skb_copy copy arp field
+ * Andi Kleen : slabified it.
+ *
+ * NOTE:
+ * The __skb_ routines should be called with interrupts
+ * disabled, or you better be *real* sure that the operation is atomic
+ * with respect to whatever list is being frobbed (e.g. via lock_sock()
+ * or via disabling bottom half handlers, etc).
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+/*
+ * The functions in this file will not compile correctly with gcc 2.4.x
+ */
+
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/in.h>
+#include <linux/inet.h>
+#include <linux/slab.h>
+#include <linux/netdevice.h>
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <linux/cache.h>
+#include <linux/rtnetlink.h>
+#include <linux/init.h>
+#include <linux/highmem.h>
+
+#include <net/protocol.h>
+#include <net/dst.h>
+#include <net/sock.h>
+#include <net/checksum.h>
+
+#include <asm/uaccess.h>
+#include <asm/system.h>
+
+int sysctl_hot_list_len = 128;
+
+static kmem_cache_t *skbuff_head_cache;
+
+static union {
+ struct sk_buff_head list;
+ char pad[SMP_CACHE_BYTES];
+} skb_head_pool[NR_CPUS];
+
+/*
+ * Keep out-of-line to prevent kernel bloat.
+ * __builtin_return_address is not used because it is not always
+ * reliable.
+ */
+
+/**
+ * skb_over_panic - private function
+ * @skb: buffer
+ * @sz: size
+ * @here: address
+ *
+ * Out of line support code for skb_put(). Not user callable.
+ */
+
+void skb_over_panic(struct sk_buff *skb, int sz, void *here)
+{
+ printk("skput:over: %p:%d put:%d dev:%s",
+ here, skb->len, sz, skb->dev ? skb->dev->name : "<NULL>");
+ BUG();
+}
+
+/**
+ * skb_under_panic - private function
+ * @skb: buffer
+ * @sz: size
+ * @here: address
+ *
+ * Out of line support code for skb_push(). Not user callable.
+ */
+
+
+void skb_under_panic(struct sk_buff *skb, int sz, void *here)
+{
+ printk("skput:under: %p:%d put:%d dev:%s",
+ here, skb->len, sz, skb->dev ? skb->dev->name : "<NULL>");
+ BUG();
+}
+
+static __inline__ struct sk_buff *skb_head_from_pool(void)
+{
+ struct sk_buff_head *list = &skb_head_pool[smp_processor_id()].list;
+
+ if (skb_queue_len(list)) {
+ struct sk_buff *skb;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ skb = __skb_dequeue(list);
+ local_irq_restore(flags);
+ return skb;
+ }
+ return NULL;
+}
+
+static __inline__ void skb_head_to_pool(struct sk_buff *skb)
+{
+ struct sk_buff_head *list = &skb_head_pool[smp_processor_id()].list;
+
+ if (skb_queue_len(list) < sysctl_hot_list_len) {
+ unsigned long flags;
+
+ local_irq_save(flags);
+ __skb_queue_head(list, skb);
+ local_irq_restore(flags);
+
+ return;
+ }
+ kmem_cache_free(skbuff_head_cache, skb);
+}
+
+
+/* Allocate a new skbuff. We do this ourselves so we can fill in a few
+ * 'private' fields and also do memory statistics to find all the
+ * [BEEP] leaks.
+ *
+ */
+
+/**
+ * alloc_skb - allocate a network buffer
+ * @size: size to allocate
+ * @gfp_mask: allocation mask
+ *
+ * Allocate a new &sk_buff. The returned buffer has no headroom and a
+ * tail room of size bytes. The object has a reference count of one.
+ * The return is the buffer. On a failure the return is %NULL.
+ *
+ * Buffers may only be allocated from interrupts using a @gfp_mask of
+ * %GFP_ATOMIC.
+ */
+
+struct sk_buff *alloc_skb(unsigned int size,int gfp_mask)
+{
+ struct sk_buff *skb;
+ u8 *data;
+
+ if (in_interrupt() && (gfp_mask & __GFP_WAIT)) {
+ static int count = 0;
+ if (++count < 5) {
+ printk(KERN_ERR "alloc_skb called nonatomically "
+ "from interrupt %p\n", NET_CALLER(size));
+ BUG();
+ }
+ gfp_mask &= ~__GFP_WAIT;
+ }
+
+ /* Get the HEAD */
+ skb = skb_head_from_pool();
+ if (skb == NULL) {
+ skb = kmem_cache_alloc(skbuff_head_cache, gfp_mask & ~__GFP_DMA);
+ if (skb == NULL)
+ goto nohead;
+ }
+
+ /* Get the DATA. Size must match skb_add_mtu(). */
+ size = SKB_DATA_ALIGN(size);
+ data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask);
+ if (data == NULL)
+ goto nodata;
+
+ /* XXX: does not include slab overhead */
+ skb->truesize = size + sizeof(struct sk_buff);
+
+ /* Load the data pointers. */
+ skb->head = data;
+ skb->data = data;
+ skb->tail = data;
+ skb->end = data + size;
+
+ /* Set up other state */
+ skb->len = 0;
+ skb->cloned = 0;
+ skb->data_len = 0;
+
+ atomic_set(&skb->users, 1);
+ atomic_set(&(skb_shinfo(skb)->dataref), 1);
+ skb_shinfo(skb)->nr_frags = 0;
+ skb_shinfo(skb)->frag_list = NULL;
+ return skb;
+
+nodata:
+ skb_head_to_pool(skb);
+nohead:
+ return NULL;
+}
+
+/**
+ * alloc_skb_from_cache - allocate a network buffer
+ * @cp: kmem_cache from which to allocate the data area
+ * (object size must be big enough for @size bytes + skb overheads)
+ * @size: size to allocate
+ * @gfp_mask: allocation mask
+ *
+ * Allocate a new &sk_buff. The returned buffer has no headroom and a
+ * tail room of size bytes. The object has a reference count of one.
+ * The return is the buffer. On a failure the return is %NULL.
+ *
+ * Buffers may only be allocated from interrupts using a @gfp_mask of
+ * %GFP_ATOMIC.
+ */
+
+struct sk_buff *alloc_skb_from_cache(kmem_cache_t *cp,
+ unsigned int size, int gfp_mask)
+{
+ struct sk_buff *skb;
+ u8 *data;
+
+ if (in_interrupt() && (gfp_mask & __GFP_WAIT)) {
+ static int count = 0;
+ if (++count < 5) {
+ printk(KERN_ERR "alloc_skb called nonatomically "
+ "from interrupt %p\n", NET_CALLER(size));
+ BUG();
+ }
+ gfp_mask &= ~__GFP_WAIT;
+ }
+
+ /* Get the HEAD */
+ skb = skb_head_from_pool();
+ if (skb == NULL) {
+ skb = kmem_cache_alloc(skbuff_head_cache, gfp_mask & ~__GFP_DMA);
+ if (skb == NULL)
+ goto nohead;
+ }
+
+ /* Get the DATA. */
+ size = SKB_DATA_ALIGN(size);
+ data = kmem_cache_alloc(cp, gfp_mask);
+ if (data == NULL)
+ goto nodata;
+
+ /* XXX: does not include slab overhead */
+ skb->truesize = size + sizeof(struct sk_buff);
+
+ /* Load the data pointers. */
+ skb->head = data;
+ skb->data = data;
+ skb->tail = data;
+ skb->end = data + size;
+
+ /* Set up other state */
+ skb->len = 0;
+ skb->cloned = 0;
+ skb->data_len = 0;
+
+ atomic_set(&skb->users, 1);
+ atomic_set(&(skb_shinfo(skb)->dataref), 1);
+ skb_shinfo(skb)->nr_frags = 0;
+ skb_shinfo(skb)->frag_list = NULL;
+ return skb;
+
+nodata:
+ skb_head_to_pool(skb);
+nohead:
+ return NULL;
+}
+
+
+/*
+ * Slab constructor for a skb head.
+ */
+static inline void skb_headerinit(void *p, kmem_cache_t *cache,
+ unsigned long flags)
+{
+ struct sk_buff *skb = p;
+
+ skb->next = NULL;
+ skb->prev = NULL;
+ skb->list = NULL;
+ skb->sk = NULL;
+ skb->stamp.tv_sec=0; /* No idea about time */
+ skb->dev = NULL;
+ skb->real_dev = NULL;
+ skb->dst = NULL;
+ memset(skb->cb, 0, sizeof(skb->cb));
+ skb->pkt_type = PACKET_HOST; /* Default type */
+ skb->ip_summed = 0;
+ skb->priority = 0;
+ skb->security = 0; /* By default packets are insecure */
+ skb->destructor = NULL;
+
+#ifdef CONFIG_NETFILTER
+ skb->nfmark = skb->nfcache = 0;
+ skb->nfct = NULL;
+#ifdef CONFIG_NETFILTER_DEBUG
+ skb->nf_debug = 0;
+#endif
+#endif
+#ifdef CONFIG_NET_SCHED
+ skb->tc_index = 0;
+#endif
+}
+
+static void skb_drop_fraglist(struct sk_buff *skb)
+{
+ struct sk_buff *list = skb_shinfo(skb)->frag_list;
+
+ skb_shinfo(skb)->frag_list = NULL;
+
+ do {
+ struct sk_buff *this = list;
+ list = list->next;
+ kfree_skb(this);
+ } while (list);
+}
+
+static void skb_clone_fraglist(struct sk_buff *skb)
+{
+ struct sk_buff *list;
+
+ for (list = skb_shinfo(skb)->frag_list; list; list=list->next)
+ skb_get(list);
+}
+
+static void skb_release_data(struct sk_buff *skb)
+{
+ if (!skb->cloned ||
+ atomic_dec_and_test(&(skb_shinfo(skb)->dataref))) {
+ if (skb_shinfo(skb)->nr_frags) {
+ int i;
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+ put_page(skb_shinfo(skb)->frags[i].page);
+ }
+
+ if (skb_shinfo(skb)->frag_list)
+ skb_drop_fraglist(skb);
+
+ kfree(skb->head);
+ }
+}
+
+/*
+ * Free an skbuff by memory without cleaning the state.
+ */
+void kfree_skbmem(struct sk_buff *skb)
+{
+ skb_release_data(skb);
+ skb_head_to_pool(skb);
+}
+
+/**
+ * __kfree_skb - private function
+ * @skb: buffer
+ *
+ * Free an sk_buff. Release anything attached to the buffer.
+ * Clean the state. This is an internal helper function. Users should
+ * always call kfree_skb
+ */
+
+void __kfree_skb(struct sk_buff *skb)
+{
+ if (skb->list) {
+ printk(KERN_WARNING "Warning: kfree_skb passed an skb still "
+ "on a list (from %p).\n", NET_CALLER(skb));
+ BUG();
+ }
+
+ dst_release(skb->dst);
+ if(skb->destructor) {
+ if (in_irq()) {
+ printk(KERN_WARNING "Warning: kfree_skb on hard IRQ %p\n",
+ NET_CALLER(skb));
+ }
+ skb->destructor(skb);
+ }
+#ifdef CONFIG_NETFILTER
+ nf_conntrack_put(skb->nfct);
+#endif
+ skb_headerinit(skb, NULL, 0); /* clean state */
+ kfree_skbmem(skb);
+}
+
+/**
+ * skb_clone - duplicate an sk_buff
+ * @skb: buffer to clone
+ * @gfp_mask: allocation priority
+ *
+ * Duplicate an &sk_buff. The new one is not owned by a socket. Both
+ * copies share the same packet data but not structure. The new
+ * buffer has a reference count of 1. If the allocation fails the
+ * function returns %NULL otherwise the new buffer is returned.
+ *
+ * If this function is called from an interrupt gfp_mask() must be
+ * %GFP_ATOMIC.
+ */
+
+struct sk_buff *skb_clone(struct sk_buff *skb, int gfp_mask)
+{
+ struct sk_buff *n;
+
+ n = skb_head_from_pool();
+ if (!n) {
+ n = kmem_cache_alloc(skbuff_head_cache, gfp_mask);
+ if (!n)
+ return NULL;
+ }
+
+#define C(x) n->x = skb->x
+
+ n->next = n->prev = NULL;
+ n->list = NULL;
+ n->sk = NULL;
+ C(stamp);
+ C(dev);
+ C(real_dev);
+ C(h);
+ C(nh);
+ C(mac);
+ C(dst);
+ dst_clone(n->dst);
+ memcpy(n->cb, skb->cb, sizeof(skb->cb));
+ C(len);
+ C(data_len);
+ C(csum);
+ n->cloned = 1;
+ C(pkt_type);
+ C(ip_summed);
+ C(priority);
+ atomic_set(&n->users, 1);
+ C(protocol);
+ C(security);
+ C(truesize);
+ C(head);
+ C(data);
+ C(tail);
+ C(end);
+ n->destructor = NULL;
+#ifdef CONFIG_NETFILTER
+ C(nfmark);
+ C(nfcache);
+ C(nfct);
+#ifdef CONFIG_NETFILTER_DEBUG
+ C(nf_debug);
+#endif
+#endif /*CONFIG_NETFILTER*/
+#if defined(CONFIG_HIPPI)
+ C(private);
+#endif
+#ifdef CONFIG_NET_SCHED
+ C(tc_index);
+#endif
+
+ atomic_inc(&(skb_shinfo(skb)->dataref));
+ skb->cloned = 1;
+#ifdef CONFIG_NETFILTER
+ nf_conntrack_get(skb->nfct);
+#endif
+ return n;
+}
+
+static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
+{
+ /*
+ * Shift between the two data areas in bytes
+ */
+ unsigned long offset = new->data - old->data;
+
+ new->list=NULL;
+ new->sk=NULL;
+ new->dev=old->dev;
+ new->real_dev=old->real_dev;
+ new->priority=old->priority;
+ new->protocol=old->protocol;
+ new->dst=dst_clone(old->dst);
+ new->h.raw=old->h.raw+offset;
+ new->nh.raw=old->nh.raw+offset;
+ new->mac.raw=old->mac.raw+offset;
+ memcpy(new->cb, old->cb, sizeof(old->cb));
+ atomic_set(&new->users, 1);
+ new->pkt_type=old->pkt_type;
+ new->stamp=old->stamp;
+ new->destructor = NULL;
+ new->security=old->security;
+#ifdef CONFIG_NETFILTER
+ new->nfmark=old->nfmark;
+ new->nfcache=old->nfcache;
+ new->nfct=old->nfct;
+ nf_conntrack_get(new->nfct);
+#ifdef CONFIG_NETFILTER_DEBUG
+ new->nf_debug=old->nf_debug;
+#endif
+#endif
+#ifdef CONFIG_NET_SCHED
+ new->tc_index = old->tc_index;
+#endif
+}
+
+/**
+ * skb_copy - create private copy of an sk_buff
+ * @skb: buffer to copy
+ * @gfp_mask: allocation priority
+ *
+ * Make a copy of both an &sk_buff and its data. This is used when the
+ * caller wishes to modify the data and needs a private copy of the
+ * data to alter. Returns %NULL on failure or the pointer to the buffer
+ * on success. The returned buffer has a reference count of 1.
+ *
+ * As by-product this function converts non-linear &sk_buff to linear
+ * one, so that &sk_buff becomes completely private and caller is allowed
+ * to modify all the data of returned buffer. This means that this
+ * function is not recommended for use in circumstances when only
+ * header is going to be modified. Use pskb_copy() instead.
+ */
+
+struct sk_buff *skb_copy(const struct sk_buff *skb, int gfp_mask)
+{
+ struct sk_buff *n;
+ int headerlen = skb->data-skb->head;
+
+ /*
+ * Allocate the copy buffer
+ */
+ n=alloc_skb(skb->end - skb->head + skb->data_len, gfp_mask);
+ if(n==NULL)
+ return NULL;
+
+ /* Set the data pointer */
+ skb_reserve(n,headerlen);
+ /* Set the tail pointer and length */
+ skb_put(n,skb->len);
+ n->csum = skb->csum;
+ n->ip_summed = skb->ip_summed;
+
+ if (skb_copy_bits(skb, -headerlen, n->head, headerlen+skb->len))
+ BUG();
+
+ copy_skb_header(n, skb);
+
+ return n;
+}
+
+/* Keep head the same: replace data */
+int skb_linearize(struct sk_buff *skb, int gfp_mask)
+{
+ unsigned int size;
+ u8 *data;
+ long offset;
+ int headerlen = skb->data - skb->head;
+ int expand = (skb->tail+skb->data_len) - skb->end;
+
+ if (skb_shared(skb))
+ BUG();
+
+ if (expand <= 0)
+ expand = 0;
+
+ size = (skb->end - skb->head + expand);
+ size = SKB_DATA_ALIGN(size);
+ data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask);
+ if (data == NULL)
+ return -ENOMEM;
+
+ /* Copy entire thing */
+ if (skb_copy_bits(skb, -headerlen, data, headerlen+skb->len))
+ BUG();
+
+ /* Offset between the two in bytes */
+ offset = data - skb->head;
+
+ /* Free old data. */
+ skb_release_data(skb);
+
+ skb->head = data;
+ skb->end = data + size;
+
+ /* Set up new pointers */
+ skb->h.raw += offset;
+ skb->nh.raw += offset;
+ skb->mac.raw += offset;
+ skb->tail += offset;
+ skb->data += offset;
+
+ /* Set up shinfo */
+ atomic_set(&(skb_shinfo(skb)->dataref), 1);
+ skb_shinfo(skb)->nr_frags = 0;
+ skb_shinfo(skb)->frag_list = NULL;
+
+ /* We are no longer a clone, even if we were. */
+ skb->cloned = 0;
+
+ skb->tail += skb->data_len;
+ skb->data_len = 0;
+ return 0;
+}
+
+
+/**
+ * pskb_copy - create copy of an sk_buff with private head.
+ * @skb: buffer to copy
+ * @gfp_mask: allocation priority
+ *
+ * Make a copy of both an &sk_buff and part of its data, located
+ * in header. Fragmented data remain shared. This is used when
+ * the caller wishes to modify only header of &sk_buff and needs
+ * private copy of the header to alter. Returns %NULL on failure
+ * or the pointer to the buffer on success.
+ * The returned buffer has a reference count of 1.
+ */
+
+struct sk_buff *pskb_copy(struct sk_buff *skb, int gfp_mask)
+{
+ struct sk_buff *n;
+
+ /*
+ * Allocate the copy buffer
+ */
+ n=alloc_skb(skb->end - skb->head, gfp_mask);
+ if(n==NULL)
+ return NULL;
+
+ /* Set the data pointer */
+ skb_reserve(n,skb->data-skb->head);
+ /* Set the tail pointer and length */
+ skb_put(n,skb_headlen(skb));
+ /* Copy the bytes */
+ memcpy(n->data, skb->data, n->len);
+ n->csum = skb->csum;
+ n->ip_summed = skb->ip_summed;
+
+ n->data_len = skb->data_len;
+ n->len = skb->len;
+
+ if (skb_shinfo(skb)->nr_frags) {
+ int i;
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
+ get_page(skb_shinfo(n)->frags[i].page);
+ }
+ skb_shinfo(n)->nr_frags = i;
+ }
+
+ if (skb_shinfo(skb)->frag_list) {
+ skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
+ skb_clone_fraglist(n);
+ }
+
+ copy_skb_header(n, skb);
+
+ return n;
+}
+
+/**
+ * pskb_expand_head - reallocate header of &sk_buff
+ * @skb: buffer to reallocate
+ * @nhead: room to add at head
+ * @ntail: room to add at tail
+ * @gfp_mask: allocation priority
+ *
+ * Expands (or creates identical copy, if &nhead and &ntail are zero)
+ * header of skb. &sk_buff itself is not changed. &sk_buff MUST have
+ * reference count of 1. Returns zero in the case of success or error,
+ * if expansion failed. In the last case, &sk_buff is not changed.
+ *
+ * All the pointers pointing into skb header may change and must be
+ * reloaded after call to this function.
+ */
+
+int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, int gfp_mask)
+{
+ int i;
+ u8 *data;
+ int size = nhead + (skb->end - skb->head) + ntail;
+ long off;
+
+ if (skb_shared(skb))
+ BUG();
+
+ size = SKB_DATA_ALIGN(size);
+
+ data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask);
+ if (data == NULL)
+ goto nodata;
+
+ /* Copy only real data... and, alas, header. This should be
+ * optimized for the cases when header is void. */
+ memcpy(data+nhead, skb->head, skb->tail-skb->head);
+ memcpy(data+size, skb->end, sizeof(struct skb_shared_info));
+
+ for (i=0; i<skb_shinfo(skb)->nr_frags; i++)
+ get_page(skb_shinfo(skb)->frags[i].page);
+
+ if (skb_shinfo(skb)->frag_list)
+ skb_clone_fraglist(skb);
+
+ skb_release_data(skb);
+
+ off = (data+nhead) - skb->head;
+
+ skb->head = data;
+ skb->end = data+size;
+
+ skb->data += off;
+ skb->tail += off;
+ skb->mac.raw += off;
+ skb->h.raw += off;
+ skb->nh.raw += off;
+ skb->cloned = 0;
+ atomic_set(&skb_shinfo(skb)->dataref, 1);
+ return 0;
+
+nodata:
+ return -ENOMEM;
+}
+
+/* Make private copy of skb with writable head and some headroom */
+
+struct sk_buff *
+skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom)
+{
+ struct sk_buff *skb2;
+ int delta = headroom - skb_headroom(skb);
+
+ if (delta <= 0)
+ return pskb_copy(skb, GFP_ATOMIC);
+
+ skb2 = skb_clone(skb, GFP_ATOMIC);
+ if (skb2 == NULL ||
+ !pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0, GFP_ATOMIC))
+ return skb2;
+
+ kfree_skb(skb2);
+ return NULL;
+}
+
+
+/**
+ * skb_copy_expand - copy and expand sk_buff
+ * @skb: buffer to copy
+ * @newheadroom: new free bytes at head
+ * @newtailroom: new free bytes at tail
+ * @gfp_mask: allocation priority
+ *
+ * Make a copy of both an &sk_buff and its data and while doing so
+ * allocate additional space.
+ *
+ * This is used when the caller wishes to modify the data and needs a
+ * private copy of the data to alter as well as more space for new fields.
+ * Returns %NULL on failure or the pointer to the buffer
+ * on success. The returned buffer has a reference count of 1.
+ *
+ * You must pass %GFP_ATOMIC as the allocation priority if this function
+ * is called from an interrupt.
+ */
+
+
+struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
+ int newheadroom,
+ int newtailroom,
+ int gfp_mask)
+{
+ struct sk_buff *n;
+
+ /*
+ * Allocate the copy buffer
+ */
+
+ n=alloc_skb(newheadroom + skb->len + newtailroom,
+ gfp_mask);
+ if(n==NULL)
+ return NULL;
+
+ skb_reserve(n,newheadroom);
+
+ /* Set the tail pointer and length */
+ skb_put(n,skb->len);
+
+ /* Copy the data only. */
+ if (skb_copy_bits(skb, 0, n->data, skb->len))
+ BUG();
+
+ copy_skb_header(n, skb);
+ return n;
+}
+
+/**
+ * skb_pad - zero pad the tail of an skb
+ * @skb: buffer to pad
+ * @pad: space to pad
+ *
+ * Ensure that a buffer is followed by a padding area that is zero
+ * filled. Used by network drivers which may DMA or transfer data
+ * beyond the buffer end onto the wire.
+ *
+ * May return NULL in out of memory cases.
+ */
+
+struct sk_buff *skb_pad(struct sk_buff *skb, int pad)
+{
+ struct sk_buff *nskb;
+
+ /* If the skbuff is non linear tailroom is always zero.. */
+ if(skb_tailroom(skb) >= pad)
+ {
+ memset(skb->data+skb->len, 0, pad);
+ return skb;
+ }
+
+ nskb = skb_copy_expand(skb, skb_headroom(skb), skb_tailroom(skb) + pad, GFP_ATOMIC);
+ kfree_skb(skb);
+ if(nskb)
+ memset(nskb->data+nskb->len, 0, pad);
+ return nskb;
+}
+
+/* Trims skb to length len. It can change skb pointers, if "realloc" is 1.
+ * If realloc==0 and trimming is impossible without change of data,
+ * it is BUG().
+ */
+
+int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc)
+{
+ int offset = skb_headlen(skb);
+ int nfrags = skb_shinfo(skb)->nr_frags;
+ int i;
+
+ for (i=0; i<nfrags; i++) {
+ int end = offset + skb_shinfo(skb)->frags[i].size;
+ if (end > len) {
+ if (skb_cloned(skb)) {
+ if (!realloc)
+ BUG();
+ if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+ return -ENOMEM;
+ }
+ if (len <= offset) {
+ put_page(skb_shinfo(skb)->frags[i].page);
+ skb_shinfo(skb)->nr_frags--;
+ } else {
+ skb_shinfo(skb)->frags[i].size = len-offset;
+ }
+ }
+ offset = end;
+ }
+
+ if (offset < len) {
+ skb->data_len -= skb->len - len;
+ skb->len = len;
+ } else {
+ if (len <= skb_headlen(skb)) {
+ skb->len = len;
+ skb->data_len = 0;
+ skb->tail = skb->data + len;
+ if (skb_shinfo(skb)->frag_list && !skb_cloned(skb))
+ skb_drop_fraglist(skb);
+ } else {
+ skb->data_len -= skb->len - len;
+ skb->len = len;
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * __pskb_pull_tail - advance tail of skb header
+ * @skb: buffer to reallocate
+ * @delta: number of bytes to advance tail
+ *
+ * The function makes a sense only on a fragmented &sk_buff,
+ * it expands header moving its tail forward and copying necessary
+ * data from fragmented part.
+ *
+ * &sk_buff MUST have reference count of 1.
+ *
+ * Returns %NULL (and &sk_buff does not change) if pull failed
+ * or value of new tail of skb in the case of success.
+ *
+ * All the pointers pointing into skb header may change and must be
+ * reloaded after call to this function.
+ */
+
+/* Moves tail of skb head forward, copying data from fragmented part,
+ * when it is necessary.
+ * 1. It may fail due to malloc failure.
+ * 2. It may change skb pointers.
+ *
+ * It is pretty complicated. Luckily, it is called only in exceptional cases.
+ */
+unsigned char * __pskb_pull_tail(struct sk_buff *skb, int delta)
+{
+ int i, k, eat;
+
+ /* If skb has not enough free space at tail, get new one
+ * plus 128 bytes for future expansions. If we have enough
+ * room at tail, reallocate without expansion only if skb is cloned.
+ */
+ eat = (skb->tail+delta) - skb->end;
+
+ if (eat > 0 || skb_cloned(skb)) {
+ if (pskb_expand_head(skb, 0, eat>0 ? eat+128 : 0, GFP_ATOMIC))
+ return NULL;
+ }
+
+ if (skb_copy_bits(skb, skb_headlen(skb), skb->tail, delta))
+ BUG();
+
+ /* Optimization: no fragments, no reasons to preestimate
+ * size of pulled pages. Superb.
+ */
+ if (skb_shinfo(skb)->frag_list == NULL)
+ goto pull_pages;
+
+ /* Estimate size of pulled pages. */
+ eat = delta;
+ for (i=0; i<skb_shinfo(skb)->nr_frags; i++) {
+ if (skb_shinfo(skb)->frags[i].size >= eat)
+ goto pull_pages;
+ eat -= skb_shinfo(skb)->frags[i].size;
+ }
+
+ /* If we need update frag list, we are in troubles.
+ * Certainly, it possible to add an offset to skb data,
+ * but taking into account that pulling is expected to
+ * be very rare operation, it is worth to fight against
+ * further bloating skb head and crucify ourselves here instead.
+ * Pure masohism, indeed. 8)8)
+ */
+ if (eat) {
+ struct sk_buff *list = skb_shinfo(skb)->frag_list;
+ struct sk_buff *clone = NULL;
+ struct sk_buff *insp = NULL;
+
+ do {
+ if (list == NULL)
+ BUG();
+
+ if (list->len <= eat) {
+ /* Eaten as whole. */
+ eat -= list->len;
+ list = list->next;
+ insp = list;
+ } else {
+ /* Eaten partially. */
+
+ if (skb_shared(list)) {
+ /* Sucks! We need to fork list. :-( */
+ clone = skb_clone(list, GFP_ATOMIC);
+ if (clone == NULL)
+ return NULL;
+ insp = list->next;
+ list = clone;
+ } else {
+ /* This may be pulled without
+ * problems. */
+ insp = list;
+ }
+ if (pskb_pull(list, eat) == NULL) {
+ if (clone)
+ kfree_skb(clone);
+ return NULL;
+ }
+ break;
+ }
+ } while (eat);
+
+ /* Free pulled out fragments. */
+ while ((list = skb_shinfo(skb)->frag_list) != insp) {
+ skb_shinfo(skb)->frag_list = list->next;
+ kfree_skb(list);
+ }
+ /* And insert new clone at head. */
+ if (clone) {
+ clone->next = list;
+ skb_shinfo(skb)->frag_list = clone;
+ }
+ }
+ /* Success! Now we may commit changes to skb data. */
+
+pull_pages:
+ eat = delta;
+ k = 0;
+ for (i=0; i<skb_shinfo(skb)->nr_frags; i++) {
+ if (skb_shinfo(skb)->frags[i].size <= eat) {
+ put_page(skb_shinfo(skb)->frags[i].page);
+ eat -= skb_shinfo(skb)->frags[i].size;
+ } else {
+ skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i];
+ if (eat) {
+ skb_shinfo(skb)->frags[k].page_offset += eat;
+ skb_shinfo(skb)->frags[k].size -= eat;
+ eat = 0;
+ }
+ k++;
+ }
+ }
+ skb_shinfo(skb)->nr_frags = k;
+
+ skb->tail += delta;
+ skb->data_len -= delta;
+
+ return skb->tail;
+}
+
+/* Copy some data bits from skb to kernel buffer. */
+
+int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
+{
+ int i, copy;
+ int start = skb->len - skb->data_len;
+
+ if (offset > (int)skb->len-len)
+ goto fault;
+
+ /* Copy header. */
+ if ((copy = start-offset) > 0) {
+ if (copy > len)
+ copy = len;
+ memcpy(to, skb->data + offset, copy);
+ if ((len -= copy) == 0)
+ return 0;
+ offset += copy;
+ to += copy;
+ }
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ int end;
+
+ BUG_TRAP(start <= offset+len);
+
+ end = start + skb_shinfo(skb)->frags[i].size;
+ if ((copy = end-offset) > 0) {
+ u8 *vaddr;
+
+ if (copy > len)
+ copy = len;
+
+ vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]);
+ memcpy(to, vaddr+skb_shinfo(skb)->frags[i].page_offset+
+ offset-start, copy);
+ kunmap_skb_frag(vaddr);
+
+ if ((len -= copy) == 0)
+ return 0;
+ offset += copy;
+ to += copy;
+ }
+ start = end;
+ }
+
+ if (skb_shinfo(skb)->frag_list) {
+ struct sk_buff *list;
+
+ for (list = skb_shinfo(skb)->frag_list; list; list=list->next) {
+ int end;
+
+ BUG_TRAP(start <= offset+len);
+
+ end = start + list->len;
+ if ((copy = end-offset) > 0) {
+ if (copy > len)
+ copy = len;
+ if (skb_copy_bits(list, offset-start, to, copy))
+ goto fault;
+ if ((len -= copy) == 0)
+ return 0;
+ offset += copy;
+ to += copy;
+ }
+ start = end;
+ }
+ }
+ if (len == 0)
+ return 0;
+
+fault:
+ return -EFAULT;
+}
+
+/* Checksum skb data. */
+
+unsigned int skb_checksum(const struct sk_buff *skb, int offset, int len, unsigned int csum)
+{
+ int i, copy;
+ int start = skb->len - skb->data_len;
+ int pos = 0;
+
+ /* Checksum header. */
+ if ((copy = start-offset) > 0) {
+ if (copy > len)
+ copy = len;
+ csum = csum_partial(skb->data+offset, copy, csum);
+ if ((len -= copy) == 0)
+ return csum;
+ offset += copy;
+ pos = copy;
+ }
+
+ for (i=0; i<skb_shinfo(skb)->nr_frags; i++) {
+ int end;
+
+ BUG_TRAP(start <= offset+len);
+
+ end = start + skb_shinfo(skb)->frags[i].size;
+ if ((copy = end-offset) > 0) {
+ unsigned int csum2;
+ u8 *vaddr;
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+ if (copy > len)
+ copy = len;
+ vaddr = kmap_skb_frag(frag);
+ csum2 = csum_partial(vaddr + frag->page_offset +
+ offset-start, copy, 0);
+ kunmap_skb_frag(vaddr);
+ csum = csum_block_add(csum, csum2, pos);
+ if (!(len -= copy))
+ return csum;
+ offset += copy;
+ pos += copy;
+ }
+ start = end;
+ }
+
+ if (skb_shinfo(skb)->frag_list) {
+ struct sk_buff *list;
+
+ for (list = skb_shinfo(skb)->frag_list; list; list=list->next) {
+ int end;
+
+ BUG_TRAP(start <= offset+len);
+
+ end = start + list->len;
+ if ((copy = end-offset) > 0) {
+ unsigned int csum2;
+ if (copy > len)
+ copy = len;
+ csum2 = skb_checksum(list, offset-start, copy, 0);
+ csum = csum_block_add(csum, csum2, pos);
+ if ((len -= copy) == 0)
+ return csum;
+ offset += copy;
+ pos += copy;
+ }
+ start = end;
+ }
+ }
+ if (len == 0)
+ return csum;
+
+ BUG();
+ return csum;
+}
+
+/* Both of above in one bottle. */
+
+unsigned int skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to, int len, unsigned int csum)
+{
+ int i, copy;
+ int start = skb->len - skb->data_len;
+ int pos = 0;
+
+ /* Copy header. */
+ if ((copy = start-offset) > 0) {
+ if (copy > len)
+ copy = len;
+ csum = csum_partial_copy_nocheck(skb->data+offset, to, copy, csum);
+ if ((len -= copy) == 0)
+ return csum;
+ offset += copy;
+ to += copy;
+ pos = copy;
+ }
+
+ for (i=0; i<skb_shinfo(skb)->nr_frags; i++) {
+ int end;
+
+ BUG_TRAP(start <= offset+len);
+
+ end = start + skb_shinfo(skb)->frags[i].size;
+ if ((copy = end-offset) > 0) {
+ unsigned int csum2;
+ u8 *vaddr;
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+ if (copy > len)
+ copy = len;
+ vaddr = kmap_skb_frag(frag);
+ csum2 = csum_partial_copy_nocheck(vaddr + frag->page_offset +
+ offset-start, to, copy, 0);
+ kunmap_skb_frag(vaddr);
+ csum = csum_block_add(csum, csum2, pos);
+ if (!(len -= copy))
+ return csum;
+ offset += copy;
+ to += copy;
+ pos += copy;
+ }
+ start = end;
+ }
+
+ if (skb_shinfo(skb)->frag_list) {
+ struct sk_buff *list;
+
+ for (list = skb_shinfo(skb)->frag_list; list; list=list->next) {
+ unsigned int csum2;
+ int end;
+
+ BUG_TRAP(start <= offset+len);
+
+ end = start + list->len;
+ if ((copy = end-offset) > 0) {
+ if (copy > len)
+ copy = len;
+ csum2 = skb_copy_and_csum_bits(list, offset-start, to, copy, 0);
+ csum = csum_block_add(csum, csum2, pos);
+ if ((len -= copy) == 0)
+ return csum;
+ offset += copy;
+ to += copy;
+ pos += copy;
+ }
+ start = end;
+ }
+ }
+ if (len == 0)
+ return csum;
+
+ BUG();
+ return csum;
+}
+
+void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
+{
+ unsigned int csum;
+ long csstart;
+
+ if (skb->ip_summed == CHECKSUM_HW)
+ csstart = skb->h.raw - skb->data;
+ else
+ csstart = skb->len - skb->data_len;
+
+ if (csstart > skb->len - skb->data_len)
+ BUG();
+
+ memcpy(to, skb->data, csstart);
+
+ csum = 0;
+ if (csstart != skb->len)
+ csum = skb_copy_and_csum_bits(skb, csstart, to+csstart,
+ skb->len-csstart, 0);
+
+ if (skb->ip_summed == CHECKSUM_HW) {
+ long csstuff = csstart + skb->csum;
+
+ *((unsigned short *)(to + csstuff)) = csum_fold(csum);
+ }
+}
+
+#if 0
+/*
+ * Tune the memory allocator for a new MTU size.
+ */
+void skb_add_mtu(int mtu)
+{
+ /* Must match allocation in alloc_skb */
+ mtu = SKB_DATA_ALIGN(mtu) + sizeof(struct skb_shared_info);
+
+ kmem_add_cache_size(mtu);
+}
+#endif
+
+void __init skb_init(void)
+{
+ int i;
+
+ skbuff_head_cache = kmem_cache_create("skbuff_head_cache",
+ sizeof(struct sk_buff),
+ 0,
+ SLAB_HWCACHE_ALIGN,
+ skb_headerinit, NULL);
+ if (!skbuff_head_cache)
+ panic("cannot create skbuff cache");
+
+ for (i=0; i<NR_CPUS; i++)
+ skb_queue_head_init(&skb_head_pool[i].list);
+}
--- /dev/null
+/*
+ * Routines having to do with the 'struct sk_buff' memory handlers.
+ *
+ * Authors: Alan Cox <iiitac@pyr.swan.ac.uk>
+ * Florian La Roche <rzsfl@rz.uni-sb.de>
+ *
+ * Version: $Id: skbuff.c,v 1.90 2001/11/07 05:56:19 davem Exp $
+ *
+ * Fixes:
+ * Alan Cox : Fixed the worst of the load
+ * balancer bugs.
+ * Dave Platt : Interrupt stacking fix.
+ * Richard Kooijman : Timestamp fixes.
+ * Alan Cox : Changed buffer format.
+ * Alan Cox : destructor hook for AF_UNIX etc.
+ * Linus Torvalds : Better skb_clone.
+ * Alan Cox : Added skb_copy.
+ * Alan Cox : Added all the changed routines Linus
+ * only put in the headers
+ * Ray VanTassle : Fixed --skb->lock in free
+ * Alan Cox : skb_copy copy arp field
+ * Andi Kleen : slabified it.
+ * Robert Olsson : Removed skb_head_pool
+ *
+ * NOTE:
+ * The __skb_ routines should be called with interrupts
+ * disabled, or you better be *real* sure that the operation is atomic
+ * with respect to whatever list is being frobbed (e.g. via lock_sock()
+ * or via disabling bottom half handlers, etc).
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+/*
+ * The functions in this file will not compile correctly with gcc 2.4.x
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/in.h>
+#include <linux/inet.h>
+#include <linux/slab.h>
+#include <linux/netdevice.h>
+#ifdef CONFIG_NET_CLS_ACT
+#include <net/pkt_sched.h>
+#endif
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <linux/cache.h>
+#include <linux/rtnetlink.h>
+#include <linux/init.h>
+#include <linux/highmem.h>
+
+#include <net/protocol.h>
+#include <net/dst.h>
+#include <net/sock.h>
+#include <net/checksum.h>
+#include <net/xfrm.h>
+
+#include <asm/uaccess.h>
+#include <asm/system.h>
+
+static kmem_cache_t *skbuff_head_cache;
+
+/*
+ * Keep out-of-line to prevent kernel bloat.
+ * __builtin_return_address is not used because it is not always
+ * reliable.
+ */
+
+/**
+ * skb_over_panic - private function
+ * @skb: buffer
+ * @sz: size
+ * @here: address
+ *
+ * Out of line support code for skb_put(). Not user callable.
+ */
+void skb_over_panic(struct sk_buff *skb, int sz, void *here)
+{
+ printk(KERN_INFO "skput:over: %p:%d put:%d dev:%s",
+ here, skb->len, sz, skb->dev ? skb->dev->name : "<NULL>");
+ BUG();
+}
+
+/**
+ * skb_under_panic - private function
+ * @skb: buffer
+ * @sz: size
+ * @here: address
+ *
+ * Out of line support code for skb_push(). Not user callable.
+ */
+
+void skb_under_panic(struct sk_buff *skb, int sz, void *here)
+{
+ printk(KERN_INFO "skput:under: %p:%d put:%d dev:%s",
+ here, skb->len, sz, skb->dev ? skb->dev->name : "<NULL>");
+ BUG();
+}
+
+/* Allocate a new skbuff. We do this ourselves so we can fill in a few
+ * 'private' fields and also do memory statistics to find all the
+ * [BEEP] leaks.
+ *
+ */
+
+/**
+ * alloc_skb - allocate a network buffer
+ * @size: size to allocate
+ * @gfp_mask: allocation mask
+ *
+ * Allocate a new &sk_buff. The returned buffer has no headroom and a
+ * tail room of size bytes. The object has a reference count of one.
+ * The return is the buffer. On a failure the return is %NULL.
+ *
+ * Buffers may only be allocated from interrupts using a @gfp_mask of
+ * %GFP_ATOMIC.
+ */
+struct sk_buff *alloc_skb(unsigned int size, int gfp_mask)
+{
+ struct sk_buff *skb;
+ u8 *data;
+
+ /* Get the HEAD */
+ skb = kmem_cache_alloc(skbuff_head_cache,
+ gfp_mask & ~__GFP_DMA);
+ if (!skb)
+ goto out;
+
+ /* Get the DATA. Size must match skb_add_mtu(). */
+ size = SKB_DATA_ALIGN(size);
+ data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask);
+ if (!data)
+ goto nodata;
+
+ memset(skb, 0, offsetof(struct sk_buff, truesize));
+ skb->truesize = size + sizeof(struct sk_buff);
+ atomic_set(&skb->users, 1);
+ skb->head = data;
+ skb->data = data;
+ skb->tail = data;
+ skb->end = data + size;
+
+ atomic_set(&(skb_shinfo(skb)->dataref), 1);
+ skb_shinfo(skb)->nr_frags = 0;
+ skb_shinfo(skb)->tso_size = 0;
+ skb_shinfo(skb)->tso_segs = 0;
+ skb_shinfo(skb)->frag_list = NULL;
+out:
+ return skb;
+nodata:
+ kmem_cache_free(skbuff_head_cache, skb);
+ skb = NULL;
+ goto out;
+}
+
+/**
+ * alloc_skb_from_cache - allocate a network buffer
+ * @cp: kmem_cache from which to allocate the data area
+ * (object size must be big enough for @size bytes + skb overheads)
+ * @size: size to allocate
+ * @gfp_mask: allocation mask
+ *
+ * Allocate a new &sk_buff. The returned buffer has no headroom and a
+ * tail room of size bytes. The object has a reference count of one.
+ * The return is the buffer. On a failure the return is %NULL.
+ *
+ * Buffers may only be allocated from interrupts using a @gfp_mask of
+ * %GFP_ATOMIC.
+ */
+struct sk_buff *alloc_skb_from_cache(kmem_cache_t *cp,
+ unsigned int size, int gfp_mask)
+{
+ struct sk_buff *skb;
+ u8 *data;
+
+ /* Get the HEAD */
+ skb = kmem_cache_alloc(skbuff_head_cache,
+ gfp_mask & ~__GFP_DMA);
+ if (!skb)
+ goto out;
+
+ /* Get the DATA. */
+ size = SKB_DATA_ALIGN(size);
+ data = kmem_cache_alloc(cp, gfp_mask);
+ if (!data)
+ goto nodata;
+
+ memset(skb, 0, offsetof(struct sk_buff, truesize));
+ skb->truesize = size + sizeof(struct sk_buff);
+ atomic_set(&skb->users, 1);
+ skb->head = data;
+ skb->data = data;
+ skb->tail = data;
+ skb->end = data + size;
+
+ atomic_set(&(skb_shinfo(skb)->dataref), 1);
+ skb_shinfo(skb)->nr_frags = 0;
+ skb_shinfo(skb)->tso_size = 0;
+ skb_shinfo(skb)->tso_segs = 0;
+ skb_shinfo(skb)->frag_list = NULL;
+out:
+ return skb;
+nodata:
+ kmem_cache_free(skbuff_head_cache, skb);
+ skb = NULL;
+ goto out;
+}
+
+
+static void skb_drop_fraglist(struct sk_buff *skb)
+{
+ struct sk_buff *list = skb_shinfo(skb)->frag_list;
+
+ skb_shinfo(skb)->frag_list = NULL;
+
+ do {
+ struct sk_buff *this = list;
+ list = list->next;
+ kfree_skb(this);
+ } while (list);
+}
+
+static void skb_clone_fraglist(struct sk_buff *skb)
+{
+ struct sk_buff *list;
+
+ for (list = skb_shinfo(skb)->frag_list; list; list = list->next)
+ skb_get(list);
+}
+
+void skb_release_data(struct sk_buff *skb)
+{
+ if (!skb->cloned ||
+ atomic_dec_and_test(&(skb_shinfo(skb)->dataref))) {
+ if (skb_shinfo(skb)->nr_frags) {
+ int i;
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+ put_page(skb_shinfo(skb)->frags[i].page);
+ }
+
+ if (skb_shinfo(skb)->frag_list)
+ skb_drop_fraglist(skb);
+
+ kfree(skb->head);
+ }
+}
+
+/*
+ * Free an skbuff by memory without cleaning the state.
+ */
+void kfree_skbmem(struct sk_buff *skb)
+{
+ skb_release_data(skb);
+ kmem_cache_free(skbuff_head_cache, skb);
+}
+
+/**
+ * __kfree_skb - private function
+ * @skb: buffer
+ *
+ * Free an sk_buff. Release anything attached to the buffer.
+ * Clean the state. This is an internal helper function. Users should
+ * always call kfree_skb
+ */
+
+void __kfree_skb(struct sk_buff *skb)
+{
+ if (skb->list) {
+ printk(KERN_WARNING "Warning: kfree_skb passed an skb still "
+ "on a list (from %p).\n", NET_CALLER(skb));
+ BUG();
+ }
+
+ dst_release(skb->dst);
+#ifdef CONFIG_XFRM
+ secpath_put(skb->sp);
+#endif
+ if(skb->destructor) {
+ if (in_irq())
+ printk(KERN_WARNING "Warning: kfree_skb on "
+ "hard IRQ %p\n", NET_CALLER(skb));
+ skb->destructor(skb);
+ }
+#ifdef CONFIG_NETFILTER
+ nf_conntrack_put(skb->nfct);
+#ifdef CONFIG_BRIDGE_NETFILTER
+ nf_bridge_put(skb->nf_bridge);
+#endif
+#endif
+/* XXX: IS this still necessary? - JHS */
+#ifdef CONFIG_NET_SCHED
+ skb->tc_index = 0;
+#ifdef CONFIG_NET_CLS_ACT
+ skb->tc_verd = 0;
+ skb->tc_classid = 0;
+#endif
+#endif
+
+ kfree_skbmem(skb);
+}
+
+/**
+ * skb_clone - duplicate an sk_buff
+ * @skb: buffer to clone
+ * @gfp_mask: allocation priority
+ *
+ * Duplicate an &sk_buff. The new one is not owned by a socket. Both
+ * copies share the same packet data but not structure. The new
+ * buffer has a reference count of 1. If the allocation fails the
+ * function returns %NULL otherwise the new buffer is returned.
+ *
+ * If this function is called from an interrupt gfp_mask() must be
+ * %GFP_ATOMIC.
+ */
+
+struct sk_buff *skb_clone(struct sk_buff *skb, int gfp_mask)
+{
+ struct sk_buff *n = kmem_cache_alloc(skbuff_head_cache, gfp_mask);
+
+ if (!n)
+ return NULL;
+
+#define C(x) n->x = skb->x
+
+ n->next = n->prev = NULL;
+ n->list = NULL;
+ n->sk = NULL;
+ C(stamp);
+ C(dev);
+ C(real_dev);
+ C(h);
+ C(nh);
+ C(mac);
+ C(dst);
+ dst_clone(skb->dst);
+ C(sp);
+#ifdef CONFIG_INET
+ secpath_get(skb->sp);
+#endif
+ memcpy(n->cb, skb->cb, sizeof(skb->cb));
+ C(len);
+ C(data_len);
+ C(csum);
+ C(local_df);
+ n->cloned = 1;
+ C(pkt_type);
+ C(ip_summed);
+ C(priority);
+ C(protocol);
+ C(security);
+ n->destructor = NULL;
+#ifdef CONFIG_NETFILTER
+ C(nfmark);
+ C(nfcache);
+ C(nfct);
+ nf_conntrack_get(skb->nfct);
+#ifdef CONFIG_NETFILTER_DEBUG
+ C(nf_debug);
+#endif
+#ifdef CONFIG_BRIDGE_NETFILTER
+ C(nf_bridge);
+ nf_bridge_get(skb->nf_bridge);
+#endif
+#endif /*CONFIG_NETFILTER*/
+#if defined(CONFIG_HIPPI)
+ C(private);
+#endif
+#ifdef CONFIG_NET_SCHED
+ C(tc_index);
+#ifdef CONFIG_NET_CLS_ACT
+ n->tc_verd = SET_TC_VERD(skb->tc_verd,0);
+ n->tc_verd = CLR_TC_OK2MUNGE(skb->tc_verd);
+ n->tc_verd = CLR_TC_MUNGED(skb->tc_verd);
+ C(input_dev);
+ C(tc_classid);
+#endif
+
+#endif
+ C(truesize);
+ atomic_set(&n->users, 1);
+ C(head);
+ C(data);
+ C(tail);
+ C(end);
+
+ atomic_inc(&(skb_shinfo(skb)->dataref));
+ skb->cloned = 1;
+
+ return n;
+}
+
+static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
+{
+ /*
+ * Shift between the two data areas in bytes
+ */
+ unsigned long offset = new->data - old->data;
+
+ new->list = NULL;
+ new->sk = NULL;
+ new->dev = old->dev;
+ new->real_dev = old->real_dev;
+ new->priority = old->priority;
+ new->protocol = old->protocol;
+ new->dst = dst_clone(old->dst);
+#ifdef CONFIG_INET
+ new->sp = secpath_get(old->sp);
+#endif
+ new->h.raw = old->h.raw + offset;
+ new->nh.raw = old->nh.raw + offset;
+ new->mac.raw = old->mac.raw + offset;
+ memcpy(new->cb, old->cb, sizeof(old->cb));
+ new->local_df = old->local_df;
+ new->pkt_type = old->pkt_type;
+ new->stamp = old->stamp;
+ new->destructor = NULL;
+ new->security = old->security;
+#ifdef CONFIG_NETFILTER
+ new->nfmark = old->nfmark;
+ new->nfcache = old->nfcache;
+ new->nfct = old->nfct;
+ nf_conntrack_get(old->nfct);
+#ifdef CONFIG_NETFILTER_DEBUG
+ new->nf_debug = old->nf_debug;
+#endif
+#ifdef CONFIG_BRIDGE_NETFILTER
+ new->nf_bridge = old->nf_bridge;
+ nf_bridge_get(old->nf_bridge);
+#endif
+#endif
+#ifdef CONFIG_NET_SCHED
+#ifdef CONFIG_NET_CLS_ACT
+ new->tc_verd = old->tc_verd;
+#endif
+ new->tc_index = old->tc_index;
+#endif
+ atomic_set(&new->users, 1);
+}
+
+/**
+ * skb_copy - create private copy of an sk_buff
+ * @skb: buffer to copy
+ * @gfp_mask: allocation priority
+ *
+ * Make a copy of both an &sk_buff and its data. This is used when the
+ * caller wishes to modify the data and needs a private copy of the
+ * data to alter. Returns %NULL on failure or the pointer to the buffer
+ * on success. The returned buffer has a reference count of 1.
+ *
+ * As by-product this function converts non-linear &sk_buff to linear
+ * one, so that &sk_buff becomes completely private and caller is allowed
+ * to modify all the data of returned buffer. This means that this
+ * function is not recommended for use in circumstances when only
+ * header is going to be modified. Use pskb_copy() instead.
+ */
+
+struct sk_buff *skb_copy(const struct sk_buff *skb, int gfp_mask)
+{
+ int headerlen = skb->data - skb->head;
+ /*
+ * Allocate the copy buffer
+ */
+ struct sk_buff *n = alloc_skb(skb->end - skb->head + skb->data_len,
+ gfp_mask);
+ if (!n)
+ return NULL;
+
+ /* Set the data pointer */
+ skb_reserve(n, headerlen);
+ /* Set the tail pointer and length */
+ skb_put(n, skb->len);
+ n->csum = skb->csum;
+ n->ip_summed = skb->ip_summed;
+
+ if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len))
+ BUG();
+
+ copy_skb_header(n, skb);
+ return n;
+}
+
+
+/**
+ * pskb_copy - create copy of an sk_buff with private head.
+ * @skb: buffer to copy
+ * @gfp_mask: allocation priority
+ *
+ * Make a copy of both an &sk_buff and part of its data, located
+ * in header. Fragmented data remain shared. This is used when
+ * the caller wishes to modify only header of &sk_buff and needs
+ * private copy of the header to alter. Returns %NULL on failure
+ * or the pointer to the buffer on success.
+ * The returned buffer has a reference count of 1.
+ */
+
+struct sk_buff *pskb_copy(struct sk_buff *skb, int gfp_mask)
+{
+ /*
+ * Allocate the copy buffer
+ */
+ struct sk_buff *n = alloc_skb(skb->end - skb->head, gfp_mask);
+
+ if (!n)
+ goto out;
+
+ /* Set the data pointer */
+ skb_reserve(n, skb->data - skb->head);
+ /* Set the tail pointer and length */
+ skb_put(n, skb_headlen(skb));
+ /* Copy the bytes */
+ memcpy(n->data, skb->data, n->len);
+ n->csum = skb->csum;
+ n->ip_summed = skb->ip_summed;
+
+ n->data_len = skb->data_len;
+ n->len = skb->len;
+
+ if (skb_shinfo(skb)->nr_frags) {
+ int i;
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
+ get_page(skb_shinfo(n)->frags[i].page);
+ }
+ skb_shinfo(n)->nr_frags = i;
+ }
+ skb_shinfo(n)->tso_size = skb_shinfo(skb)->tso_size;
+ skb_shinfo(n)->tso_segs = skb_shinfo(skb)->tso_segs;
+
+ if (skb_shinfo(skb)->frag_list) {
+ skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
+ skb_clone_fraglist(n);
+ }
+
+ copy_skb_header(n, skb);
+out:
+ return n;
+}
+
+/**
+ * pskb_expand_head - reallocate header of &sk_buff
+ * @skb: buffer to reallocate
+ * @nhead: room to add at head
+ * @ntail: room to add at tail
+ * @gfp_mask: allocation priority
+ *
+ * Expands (or creates identical copy, if &nhead and &ntail are zero)
+ * header of skb. &sk_buff itself is not changed. &sk_buff MUST have
+ * reference count of 1. Returns zero in the case of success or error,
+ * if expansion failed. In the last case, &sk_buff is not changed.
+ *
+ * All the pointers pointing into skb header may change and must be
+ * reloaded after call to this function.
+ */
+
+int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, int gfp_mask)
+{
+ int i;
+ u8 *data;
+ int size = nhead + (skb->end - skb->head) + ntail;
+ long off;
+
+ if (skb_shared(skb))
+ BUG();
+
+ size = SKB_DATA_ALIGN(size);
+
+ data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask);
+ if (!data)
+ goto nodata;
+
+ /* Copy only real data... and, alas, header. This should be
+ * optimized for the cases when header is void. */
+ memcpy(data + nhead, skb->head, skb->tail - skb->head);
+ memcpy(data + size, skb->end, sizeof(struct skb_shared_info));
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+ get_page(skb_shinfo(skb)->frags[i].page);
+
+ if (skb_shinfo(skb)->frag_list)
+ skb_clone_fraglist(skb);
+
+ skb_release_data(skb);
+
+ off = (data + nhead) - skb->head;
+
+ skb->head = data;
+ skb->end = data + size;
+ skb->data += off;
+ skb->tail += off;
+ skb->mac.raw += off;
+ skb->h.raw += off;
+ skb->nh.raw += off;
+ skb->cloned = 0;
+ atomic_set(&skb_shinfo(skb)->dataref, 1);
+ return 0;
+
+nodata:
+ return -ENOMEM;
+}
+
+/* Make private copy of skb with writable head and some headroom */
+
+struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom)
+{
+ struct sk_buff *skb2;
+ int delta = headroom - skb_headroom(skb);
+
+ if (delta <= 0)
+ skb2 = pskb_copy(skb, GFP_ATOMIC);
+ else {
+ skb2 = skb_clone(skb, GFP_ATOMIC);
+ if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0,
+ GFP_ATOMIC)) {
+ kfree_skb(skb2);
+ skb2 = NULL;
+ }
+ }
+ return skb2;
+}
+
+
+/**
+ * skb_copy_expand - copy and expand sk_buff
+ * @skb: buffer to copy
+ * @newheadroom: new free bytes at head
+ * @newtailroom: new free bytes at tail
+ * @gfp_mask: allocation priority
+ *
+ * Make a copy of both an &sk_buff and its data and while doing so
+ * allocate additional space.
+ *
+ * This is used when the caller wishes to modify the data and needs a
+ * private copy of the data to alter as well as more space for new fields.
+ * Returns %NULL on failure or the pointer to the buffer
+ * on success. The returned buffer has a reference count of 1.
+ *
+ * You must pass %GFP_ATOMIC as the allocation priority if this function
+ * is called from an interrupt.
+ *
+ * BUG ALERT: ip_summed is not copied. Why does this work? Is it used
+ * only by netfilter in the cases when checksum is recalculated? --ANK
+ */
+struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
+ int newheadroom, int newtailroom, int gfp_mask)
+{
+ /*
+ * Allocate the copy buffer
+ */
+ struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom,
+ gfp_mask);
+ int head_copy_len, head_copy_off;
+
+ if (!n)
+ return NULL;
+
+ skb_reserve(n, newheadroom);
+
+ /* Set the tail pointer and length */
+ skb_put(n, skb->len);
+
+ head_copy_len = skb_headroom(skb);
+ head_copy_off = 0;
+ if (newheadroom <= head_copy_len)
+ head_copy_len = newheadroom;
+ else
+ head_copy_off = newheadroom - head_copy_len;
+
+ /* Copy the linear header and data. */
+ if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
+ skb->len + head_copy_len))
+ BUG();
+
+ copy_skb_header(n, skb);
+ skb_shinfo(n)->tso_size = skb_shinfo(skb)->tso_size;
+ skb_shinfo(n)->tso_segs = skb_shinfo(skb)->tso_segs;
+
+ return n;
+}
+
+/**
+ * skb_pad - zero pad the tail of an skb
+ * @skb: buffer to pad
+ * @pad: space to pad
+ *
+ * Ensure that a buffer is followed by a padding area that is zero
+ * filled. Used by network drivers which may DMA or transfer data
+ * beyond the buffer end onto the wire.
+ *
+ * May return NULL in out of memory cases.
+ */
+
+struct sk_buff *skb_pad(struct sk_buff *skb, int pad)
+{
+ struct sk_buff *nskb;
+
+ /* If the skbuff is non linear tailroom is always zero.. */
+ if (skb_tailroom(skb) >= pad) {
+ memset(skb->data+skb->len, 0, pad);
+ return skb;
+ }
+
+ nskb = skb_copy_expand(skb, skb_headroom(skb), skb_tailroom(skb) + pad, GFP_ATOMIC);
+ kfree_skb(skb);
+ if (nskb)
+ memset(nskb->data+nskb->len, 0, pad);
+ return nskb;
+}
+
+/* Trims skb to length len. It can change skb pointers, if "realloc" is 1.
+ * If realloc==0 and trimming is impossible without change of data,
+ * it is BUG().
+ */
+
+int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc)
+{
+ int offset = skb_headlen(skb);
+ int nfrags = skb_shinfo(skb)->nr_frags;
+ int i;
+
+ for (i = 0; i < nfrags; i++) {
+ int end = offset + skb_shinfo(skb)->frags[i].size;
+ if (end > len) {
+ if (skb_cloned(skb)) {
+ if (!realloc)
+ BUG();
+ if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+ return -ENOMEM;
+ }
+ if (len <= offset) {
+ put_page(skb_shinfo(skb)->frags[i].page);
+ skb_shinfo(skb)->nr_frags--;
+ } else {
+ skb_shinfo(skb)->frags[i].size = len - offset;
+ }
+ }
+ offset = end;
+ }
+
+ if (offset < len) {
+ skb->data_len -= skb->len - len;
+ skb->len = len;
+ } else {
+ if (len <= skb_headlen(skb)) {
+ skb->len = len;
+ skb->data_len = 0;
+ skb->tail = skb->data + len;
+ if (skb_shinfo(skb)->frag_list && !skb_cloned(skb))
+ skb_drop_fraglist(skb);
+ } else {
+ skb->data_len -= skb->len - len;
+ skb->len = len;
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * __pskb_pull_tail - advance tail of skb header
+ * @skb: buffer to reallocate
+ * @delta: number of bytes to advance tail
+ *
+ * The function makes a sense only on a fragmented &sk_buff,
+ * it expands header moving its tail forward and copying necessary
+ * data from fragmented part.
+ *
+ * &sk_buff MUST have reference count of 1.
+ *
+ * Returns %NULL (and &sk_buff does not change) if pull failed
+ * or value of new tail of skb in the case of success.
+ *
+ * All the pointers pointing into skb header may change and must be
+ * reloaded after call to this function.
+ */
+
+/* Moves tail of skb head forward, copying data from fragmented part,
+ * when it is necessary.
+ * 1. It may fail due to malloc failure.
+ * 2. It may change skb pointers.
+ *
+ * It is pretty complicated. Luckily, it is called only in exceptional cases.
+ */
+unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta)
+{
+ /* If skb has not enough free space at tail, get new one
+ * plus 128 bytes for future expansions. If we have enough
+ * room at tail, reallocate without expansion only if skb is cloned.
+ */
+ int i, k, eat = (skb->tail + delta) - skb->end;
+
+ if (eat > 0 || skb_cloned(skb)) {
+ if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0,
+ GFP_ATOMIC))
+ return NULL;
+ }
+
+ if (skb_copy_bits(skb, skb_headlen(skb), skb->tail, delta))
+ BUG();
+
+ /* Optimization: no fragments, no reasons to preestimate
+ * size of pulled pages. Superb.
+ */
+ if (!skb_shinfo(skb)->frag_list)
+ goto pull_pages;
+
+ /* Estimate size of pulled pages. */
+ eat = delta;
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ if (skb_shinfo(skb)->frags[i].size >= eat)
+ goto pull_pages;
+ eat -= skb_shinfo(skb)->frags[i].size;
+ }
+
+ /* If we need update frag list, we are in troubles.
+ * Certainly, it possible to add an offset to skb data,
+ * but taking into account that pulling is expected to
+ * be very rare operation, it is worth to fight against
+ * further bloating skb head and crucify ourselves here instead.
+ * Pure masohism, indeed. 8)8)
+ */
+ if (eat) {
+ struct sk_buff *list = skb_shinfo(skb)->frag_list;
+ struct sk_buff *clone = NULL;
+ struct sk_buff *insp = NULL;
+
+ do {
+ if (!list)
+ BUG();
+
+ if (list->len <= eat) {
+ /* Eaten as whole. */
+ eat -= list->len;
+ list = list->next;
+ insp = list;
+ } else {
+ /* Eaten partially. */
+
+ if (skb_shared(list)) {
+ /* Sucks! We need to fork list. :-( */
+ clone = skb_clone(list, GFP_ATOMIC);
+ if (!clone)
+ return NULL;
+ insp = list->next;
+ list = clone;
+ } else {
+ /* This may be pulled without
+ * problems. */
+ insp = list;
+ }
+ if (!pskb_pull(list, eat)) {
+ if (clone)
+ kfree_skb(clone);
+ return NULL;
+ }
+ break;
+ }
+ } while (eat);
+
+ /* Free pulled out fragments. */
+ while ((list = skb_shinfo(skb)->frag_list) != insp) {
+ skb_shinfo(skb)->frag_list = list->next;
+ kfree_skb(list);
+ }
+ /* And insert new clone at head. */
+ if (clone) {
+ clone->next = list;
+ skb_shinfo(skb)->frag_list = clone;
+ }
+ }
+ /* Success! Now we may commit changes to skb data. */
+
+pull_pages:
+ eat = delta;
+ k = 0;
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ if (skb_shinfo(skb)->frags[i].size <= eat) {
+ put_page(skb_shinfo(skb)->frags[i].page);
+ eat -= skb_shinfo(skb)->frags[i].size;
+ } else {
+ skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i];
+ if (eat) {
+ skb_shinfo(skb)->frags[k].page_offset += eat;
+ skb_shinfo(skb)->frags[k].size -= eat;
+ eat = 0;
+ }
+ k++;
+ }
+ }
+ skb_shinfo(skb)->nr_frags = k;
+
+ skb->tail += delta;
+ skb->data_len -= delta;
+
+ return skb->tail;
+}
+
+/* Copy some data bits from skb to kernel buffer. */
+
+int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
+{
+ int i, copy;
+ int start = skb_headlen(skb);
+
+ if (offset > (int)skb->len - len)
+ goto fault;
+
+ /* Copy header. */
+ if ((copy = start - offset) > 0) {
+ if (copy > len)
+ copy = len;
+ memcpy(to, skb->data + offset, copy);
+ if ((len -= copy) == 0)
+ return 0;
+ offset += copy;
+ to += copy;
+ }
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ int end;
+
+ BUG_TRAP(start <= offset + len);
+
+ end = start + skb_shinfo(skb)->frags[i].size;
+ if ((copy = end - offset) > 0) {
+ u8 *vaddr;
+
+ if (copy > len)
+ copy = len;
+
+ vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]);
+ memcpy(to,
+ vaddr + skb_shinfo(skb)->frags[i].page_offset+
+ offset - start, copy);
+ kunmap_skb_frag(vaddr);
+
+ if ((len -= copy) == 0)
+ return 0;
+ offset += copy;
+ to += copy;
+ }
+ start = end;
+ }
+
+ if (skb_shinfo(skb)->frag_list) {
+ struct sk_buff *list = skb_shinfo(skb)->frag_list;
+
+ for (; list; list = list->next) {
+ int end;
+
+ BUG_TRAP(start <= offset + len);
+
+ end = start + list->len;
+ if ((copy = end - offset) > 0) {
+ if (copy > len)
+ copy = len;
+ if (skb_copy_bits(list, offset - start,
+ to, copy))
+ goto fault;
+ if ((len -= copy) == 0)
+ return 0;
+ offset += copy;
+ to += copy;
+ }
+ start = end;
+ }
+ }
+ if (!len)
+ return 0;
+
+fault:
+ return -EFAULT;
+}
+
+/* Keep iterating until skb_iter_next returns false. */
+void skb_iter_first(const struct sk_buff *skb, struct skb_iter *i)
+{
+ i->len = skb_headlen(skb);
+ i->data = (unsigned char *)skb->data;
+ i->nextfrag = 0;
+ i->fraglist = NULL;
+}
+
+int skb_iter_next(const struct sk_buff *skb, struct skb_iter *i)
+{
+ /* Unmap previous, if not head fragment. */
+ if (i->nextfrag)
+ kunmap_skb_frag(i->data);
+
+ if (i->fraglist) {
+ fraglist:
+ /* We're iterating through fraglist. */
+ if (i->nextfrag < skb_shinfo(i->fraglist)->nr_frags) {
+ i->data = kmap_skb_frag(&skb_shinfo(i->fraglist)
+ ->frags[i->nextfrag]);
+ i->len = skb_shinfo(i->fraglist)->frags[i->nextfrag]
+ .size;
+ i->nextfrag++;
+ return 1;
+ }
+ /* Fragments with fragments? Too hard! */
+ BUG_ON(skb_shinfo(i->fraglist)->frag_list);
+ i->fraglist = i->fraglist->next;
+ if (!i->fraglist)
+ goto end;
+
+ i->len = skb_headlen(i->fraglist);
+ i->data = i->fraglist->data;
+ i->nextfrag = 0;
+ return 1;
+ }
+
+ if (i->nextfrag < skb_shinfo(skb)->nr_frags) {
+ i->data = kmap_skb_frag(&skb_shinfo(skb)->frags[i->nextfrag]);
+ i->len = skb_shinfo(skb)->frags[i->nextfrag].size;
+ i->nextfrag++;
+ return 1;
+ }
+
+ i->fraglist = skb_shinfo(skb)->frag_list;
+ if (i->fraglist)
+ goto fraglist;
+
+end:
+ /* Bug trap for callers */
+ i->data = NULL;
+ return 0;
+}
+
+void skb_iter_abort(const struct sk_buff *skb, struct skb_iter *i)
+{
+ /* Unmap previous, if not head fragment. */
+ if (i->data && i->nextfrag)
+ kunmap_skb_frag(i->data);
+ /* Bug trap for callers */
+ i->data = NULL;
+}
+
+/* Checksum skb data. */
+
+unsigned int skb_checksum(const struct sk_buff *skb, int offset,
+ int len, unsigned int csum)
+{
+ int start = skb_headlen(skb);
+ int i, copy = start - offset;
+ int pos = 0;
+
+ /* Checksum header. */
+ if (copy > 0) {
+ if (copy > len)
+ copy = len;
+ csum = csum_partial(skb->data + offset, copy, csum);
+ if ((len -= copy) == 0)
+ return csum;
+ offset += copy;
+ pos = copy;
+ }
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ int end;
+
+ BUG_TRAP(start <= offset + len);
+
+ end = start + skb_shinfo(skb)->frags[i].size;
+ if ((copy = end - offset) > 0) {
+ unsigned int csum2;
+ u8 *vaddr;
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+ if (copy > len)
+ copy = len;
+ vaddr = kmap_skb_frag(frag);
+ csum2 = csum_partial(vaddr + frag->page_offset +
+ offset - start, copy, 0);
+ kunmap_skb_frag(vaddr);
+ csum = csum_block_add(csum, csum2, pos);
+ if (!(len -= copy))
+ return csum;
+ offset += copy;
+ pos += copy;
+ }
+ start = end;
+ }
+
+ if (skb_shinfo(skb)->frag_list) {
+ struct sk_buff *list = skb_shinfo(skb)->frag_list;
+
+ for (; list; list = list->next) {
+ int end;
+
+ BUG_TRAP(start <= offset + len);
+
+ end = start + list->len;
+ if ((copy = end - offset) > 0) {
+ unsigned int csum2;
+ if (copy > len)
+ copy = len;
+ csum2 = skb_checksum(list, offset - start,
+ copy, 0);
+ csum = csum_block_add(csum, csum2, pos);
+ if ((len -= copy) == 0)
+ return csum;
+ offset += copy;
+ pos += copy;
+ }
+ start = end;
+ }
+ }
+ if (len)
+ BUG();
+
+ return csum;
+}
+
+/* Both of above in one bottle. */
+
+unsigned int skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
+ u8 *to, int len, unsigned int csum)
+{
+ int start = skb_headlen(skb);
+ int i, copy = start - offset;
+ int pos = 0;
+
+ /* Copy header. */
+ if (copy > 0) {
+ if (copy > len)
+ copy = len;
+ csum = csum_partial_copy_nocheck(skb->data + offset, to,
+ copy, csum);
+ if ((len -= copy) == 0)
+ return csum;
+ offset += copy;
+ to += copy;
+ pos = copy;
+ }
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ int end;
+
+ BUG_TRAP(start <= offset + len);
+
+ end = start + skb_shinfo(skb)->frags[i].size;
+ if ((copy = end - offset) > 0) {
+ unsigned int csum2;
+ u8 *vaddr;
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+ if (copy > len)
+ copy = len;
+ vaddr = kmap_skb_frag(frag);
+ csum2 = csum_partial_copy_nocheck(vaddr +
+ frag->page_offset +
+ offset - start, to,
+ copy, 0);
+ kunmap_skb_frag(vaddr);
+ csum = csum_block_add(csum, csum2, pos);
+ if (!(len -= copy))
+ return csum;
+ offset += copy;
+ to += copy;
+ pos += copy;
+ }
+ start = end;
+ }
+
+ if (skb_shinfo(skb)->frag_list) {
+ struct sk_buff *list = skb_shinfo(skb)->frag_list;
+
+ for (; list; list = list->next) {
+ unsigned int csum2;
+ int end;
+
+ BUG_TRAP(start <= offset + len);
+
+ end = start + list->len;
+ if ((copy = end - offset) > 0) {
+ if (copy > len)
+ copy = len;
+ csum2 = skb_copy_and_csum_bits(list,
+ offset - start,
+ to, copy, 0);
+ csum = csum_block_add(csum, csum2, pos);
+ if ((len -= copy) == 0)
+ return csum;
+ offset += copy;
+ to += copy;
+ pos += copy;
+ }
+ start = end;
+ }
+ }
+ if (len)
+ BUG();
+ return csum;
+}
+
+void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
+{
+ unsigned int csum;
+ long csstart;
+
+ if (skb->ip_summed == CHECKSUM_HW)
+ csstart = skb->h.raw - skb->data;
+ else
+ csstart = skb_headlen(skb);
+
+ if (csstart > skb_headlen(skb))
+ BUG();
+
+ memcpy(to, skb->data, csstart);
+
+ csum = 0;
+ if (csstart != skb->len)
+ csum = skb_copy_and_csum_bits(skb, csstart, to + csstart,
+ skb->len - csstart, 0);
+
+ if (skb->ip_summed == CHECKSUM_HW) {
+ long csstuff = csstart + skb->csum;
+
+ *((unsigned short *)(to + csstuff)) = csum_fold(csum);
+ }
+}
+
+/**
+ * skb_dequeue - remove from the head of the queue
+ * @list: list to dequeue from
+ *
+ * Remove the head of the list. The list lock is taken so the function
+ * may be used safely with other locking list functions. The head item is
+ * returned or %NULL if the list is empty.
+ */
+
+struct sk_buff *skb_dequeue(struct sk_buff_head *list)
+{
+ unsigned long flags;
+ struct sk_buff *result;
+
+ spin_lock_irqsave(&list->lock, flags);
+ result = __skb_dequeue(list);
+ spin_unlock_irqrestore(&list->lock, flags);
+ return result;
+}
+
+/**
+ * skb_dequeue_tail - remove from the tail of the queue
+ * @list: list to dequeue from
+ *
+ * Remove the tail of the list. The list lock is taken so the function
+ * may be used safely with other locking list functions. The tail item is
+ * returned or %NULL if the list is empty.
+ */
+struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
+{
+ unsigned long flags;
+ struct sk_buff *result;
+
+ spin_lock_irqsave(&list->lock, flags);
+ result = __skb_dequeue_tail(list);
+ spin_unlock_irqrestore(&list->lock, flags);
+ return result;
+}
+
+/**
+ * skb_queue_purge - empty a list
+ * @list: list to empty
+ *
+ * Delete all buffers on an &sk_buff list. Each buffer is removed from
+ * the list and one reference dropped. This function takes the list
+ * lock and is atomic with respect to other list locking functions.
+ */
+void skb_queue_purge(struct sk_buff_head *list)
+{
+ struct sk_buff *skb;
+ while ((skb = skb_dequeue(list)) != NULL)
+ kfree_skb(skb);
+}
+
+/**
+ * skb_queue_head - queue a buffer at the list head
+ * @list: list to use
+ * @newsk: buffer to queue
+ *
+ * Queue a buffer at the start of the list. This function takes the
+ * list lock and can be used safely with other locking &sk_buff functions
+ * safely.
+ *
+ * A buffer cannot be placed on two lists at the same time.
+ */
+void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&list->lock, flags);
+ __skb_queue_head(list, newsk);
+ spin_unlock_irqrestore(&list->lock, flags);
+}
+
+/**
+ * skb_queue_tail - queue a buffer at the list tail
+ * @list: list to use
+ * @newsk: buffer to queue
+ *
+ * Queue a buffer at the tail of the list. This function takes the
+ * list lock and can be used safely with other locking &sk_buff functions
+ * safely.
+ *
+ * A buffer cannot be placed on two lists at the same time.
+ */
+void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&list->lock, flags);
+ __skb_queue_tail(list, newsk);
+ spin_unlock_irqrestore(&list->lock, flags);
+}
+/**
+ * skb_unlink - remove a buffer from a list
+ * @skb: buffer to remove
+ *
+ * Place a packet after a given packet in a list. The list locks are taken
+ * and this function is atomic with respect to other list locked calls
+ *
+ * Works even without knowing the list it is sitting on, which can be
+ * handy at times. It also means that THE LIST MUST EXIST when you
+ * unlink. Thus a list must have its contents unlinked before it is
+ * destroyed.
+ */
+void skb_unlink(struct sk_buff *skb)
+{
+ struct sk_buff_head *list = skb->list;
+
+ if (list) {
+ unsigned long flags;
+
+ spin_lock_irqsave(&list->lock, flags);
+ if (skb->list == list)
+ __skb_unlink(skb, skb->list);
+ spin_unlock_irqrestore(&list->lock, flags);
+ }
+}
+
+
+/**
+ * skb_append - append a buffer
+ * @old: buffer to insert after
+ * @newsk: buffer to insert
+ *
+ * Place a packet after a given packet in a list. The list locks are taken
+ * and this function is atomic with respect to other list locked calls.
+ * A buffer cannot be placed on two lists at the same time.
+ */
+
+void skb_append(struct sk_buff *old, struct sk_buff *newsk)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&old->list->lock, flags);
+ __skb_append(old, newsk);
+ spin_unlock_irqrestore(&old->list->lock, flags);
+}
+
+
+/**
+ * skb_insert - insert a buffer
+ * @old: buffer to insert before
+ * @newsk: buffer to insert
+ *
+ * Place a packet before a given packet in a list. The list locks are taken
+ * and this function is atomic with respect to other list locked calls
+ * A buffer cannot be placed on two lists at the same time.
+ */
+
+void skb_insert(struct sk_buff *old, struct sk_buff *newsk)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&old->list->lock, flags);
+ __skb_insert(newsk, old->prev, old, old->list);
+ spin_unlock_irqrestore(&old->list->lock, flags);
+}
+
+#if 0
+/*
+ * Tune the memory allocator for a new MTU size.
+ */
+void skb_add_mtu(int mtu)
+{
+ /* Must match allocation in alloc_skb */
+ mtu = SKB_DATA_ALIGN(mtu) + sizeof(struct skb_shared_info);
+
+ kmem_add_cache_size(mtu);
+}
+#endif
+
+static void inline skb_split_inside_header(struct sk_buff *skb,
+ struct sk_buff* skb1,
+ const u32 len, const int pos)
+{
+ int i;
+
+ memcpy(skb_put(skb1, pos - len), skb->data + len, pos - len);
+
+ /* And move data appendix as is. */
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+ skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];
+
+ skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
+ skb_shinfo(skb)->nr_frags = 0;
+ skb1->data_len = skb->data_len;
+ skb1->len += skb1->data_len;
+ skb->data_len = 0;
+ skb->len = len;
+ skb->tail = skb->data + len;
+}
+
+static void inline skb_split_no_header(struct sk_buff *skb,
+ struct sk_buff* skb1,
+ const u32 len, int pos)
+{
+ int i, k = 0;
+ const int nfrags = skb_shinfo(skb)->nr_frags;
+
+ skb_shinfo(skb)->nr_frags = 0;
+ skb1->len = skb1->data_len = skb->len - len;
+ skb->len = len;
+ skb->data_len = len - pos;
+
+ for (i = 0; i < nfrags; i++) {
+ int size = skb_shinfo(skb)->frags[i].size;
+
+ if (pos + size > len) {
+ skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i];
+
+ if (pos < len) {
+ /* Split frag.
+ * We have to variants in this case:
+ * 1. Move all the frag to the second
+ * part, if it is possible. F.e.
+ * this approach is mandatory for TUX,
+ * where splitting is expensive.
+ * 2. Split is accurately. We make this.
+ */
+ get_page(skb_shinfo(skb)->frags[i].page);
+ skb_shinfo(skb1)->frags[0].page_offset += len - pos;
+ skb_shinfo(skb1)->frags[0].size -= len - pos;
+ skb_shinfo(skb)->frags[i].size = len - pos;
+ skb_shinfo(skb)->nr_frags++;
+ }
+ k++;
+ } else
+ skb_shinfo(skb)->nr_frags++;
+ pos += size;
+ }
+ skb_shinfo(skb1)->nr_frags = k;
+}
+
+/**
+ * skb_split - Split fragmented skb to two parts at length len.
+ */
+void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len)
+{
+ int pos = skb_headlen(skb);
+
+ if (len < pos) /* Split line is inside header. */
+ skb_split_inside_header(skb, skb1, len, pos);
+ else /* Second chunk has no header, nothing to copy. */
+ skb_split_no_header(skb, skb1, len, pos);
+}
+
+void __init skb_init(void)
+{
+ skbuff_head_cache = kmem_cache_create("skbuff_head_cache",
+ sizeof(struct sk_buff),
+ 0,
+ SLAB_HWCACHE_ALIGN,
+ NULL, NULL);
+ if (!skbuff_head_cache)
+ panic("cannot create skbuff cache");
+}
+
+EXPORT_SYMBOL(___pskb_trim);
+EXPORT_SYMBOL(__kfree_skb);
+EXPORT_SYMBOL(__pskb_pull_tail);
+EXPORT_SYMBOL(alloc_skb);
+EXPORT_SYMBOL(pskb_copy);
+EXPORT_SYMBOL(pskb_expand_head);
+EXPORT_SYMBOL(skb_checksum);
+EXPORT_SYMBOL(skb_clone);
+EXPORT_SYMBOL(skb_clone_fraglist);
+EXPORT_SYMBOL(skb_copy);
+EXPORT_SYMBOL(skb_copy_and_csum_bits);
+EXPORT_SYMBOL(skb_copy_and_csum_dev);
+EXPORT_SYMBOL(skb_copy_bits);
+EXPORT_SYMBOL(skb_copy_expand);
+EXPORT_SYMBOL(skb_over_panic);
+EXPORT_SYMBOL(skb_pad);
+EXPORT_SYMBOL(skb_realloc_headroom);
+EXPORT_SYMBOL(skb_under_panic);
+EXPORT_SYMBOL(skb_dequeue);
+EXPORT_SYMBOL(skb_dequeue_tail);
+EXPORT_SYMBOL(skb_insert);
+EXPORT_SYMBOL(skb_queue_purge);
+EXPORT_SYMBOL(skb_queue_head);
+EXPORT_SYMBOL(skb_queue_tail);
+EXPORT_SYMBOL(skb_unlink);
+EXPORT_SYMBOL(skb_append);
+EXPORT_SYMBOL(skb_split);
+EXPORT_SYMBOL(skb_iter_first);
+EXPORT_SYMBOL(skb_iter_next);
+EXPORT_SYMBOL(skb_iter_abort);
projects / xen.git / commitdiff