diff options
Diffstat (limited to 'net/core/skbuff.c')
| -rw-r--r-- | net/core/skbuff.c | 3084 |
1 files changed, 3084 insertions, 0 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c new file mode 100644 index 00000000..4821df84 --- /dev/null +++ b/net/core/skbuff.c @@ -0,0 +1,3084 @@ +/* + * Routines having to do with the 'struct sk_buff' memory handlers. + * + * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk> + * Florian La Roche <rzsfl@rz.uni-sb.de> + * + * 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/module.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/kmemcheck.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/splice.h> +#include <linux/cache.h> +#include <linux/rtnetlink.h> +#include <linux/init.h> +#include <linux/scatterlist.h> +#include <linux/errqueue.h> +#include <linux/prefetch.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> +#include <trace/events/skb.h> + +#include "kmap_skb.h" + +static struct kmem_cache *skbuff_head_cache __read_mostly; +static struct kmem_cache *skbuff_fclone_cache __read_mostly; + +static void sock_pipe_buf_release(struct pipe_inode_info *pipe, + struct pipe_buffer *buf) +{ + put_page(buf->page); +} + +static void sock_pipe_buf_get(struct pipe_inode_info *pipe, + struct pipe_buffer *buf) +{ + get_page(buf->page); +} + +static int sock_pipe_buf_steal(struct pipe_inode_info *pipe, + struct pipe_buffer *buf) +{ + return 1; +} + + +/* Pipe buffer operations for a socket. */ +static const struct pipe_buf_operations sock_pipe_buf_ops = { + .can_merge = 0, + .map = generic_pipe_buf_map, + .unmap = generic_pipe_buf_unmap, + .confirm = generic_pipe_buf_confirm, + .release = sock_pipe_buf_release, + .steal = sock_pipe_buf_steal, + .get = sock_pipe_buf_get, +}; + +/* + * 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. + */ +static void skb_over_panic(struct sk_buff *skb, int sz, void *here) +{ + printk(KERN_EMERG "skb_over_panic: text:%p len:%d put:%d head:%p " + "data:%p tail:%#lx end:%#lx dev:%s\n", + here, skb->len, sz, skb->head, skb->data, + (unsigned long)skb->tail, (unsigned long)skb->end, + 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. + */ + +static void skb_under_panic(struct sk_buff *skb, int sz, void *here) +{ + printk(KERN_EMERG "skb_under_panic: text:%p len:%d put:%d head:%p " + "data:%p tail:%#lx end:%#lx dev:%s\n", + here, skb->len, sz, skb->head, skb->data, + (unsigned long)skb->tail, (unsigned long)skb->end, + 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 + * @fclone: allocate from fclone cache instead of head cache + * and allocate a cloned (child) skb + * @node: numa node to allocate memory on + * + * 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, gfp_t gfp_mask, + int fclone, int node) +{ + struct kmem_cache *cache; + struct skb_shared_info *shinfo; + struct sk_buff *skb; + u8 *data; + + cache = fclone ? skbuff_fclone_cache : skbuff_head_cache; + + /* Get the HEAD */ + skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node); + if (!skb) + goto out; + prefetchw(skb); + + size = SKB_DATA_ALIGN(size); + data = kmalloc_node_track_caller(size + sizeof(struct skb_shared_info), + gfp_mask, node); + if (!data) + goto nodata; + prefetchw(data + size); + + /* + * Only clear those fields we need to clear, not those that we will + * actually initialise below. Hence, don't put any more fields after + * the tail pointer in struct sk_buff! + */ + memset(skb, 0, offsetof(struct sk_buff, tail)); + skb->truesize = size + sizeof(struct sk_buff); + atomic_set(&skb->users, 1); + skb->head = data; + skb->data = data; + skb_reset_tail_pointer(skb); + skb->end = skb->tail + size; +#ifdef NET_SKBUFF_DATA_USES_OFFSET + skb->mac_header = ~0U; +#endif + + /* make sure we initialize shinfo sequentially */ + shinfo = skb_shinfo(skb); + memset(shinfo, 0, offsetof(struct skb_shared_info, dataref)); + atomic_set(&shinfo->dataref, 1); + kmemcheck_annotate_variable(shinfo->destructor_arg); + + if (fclone) { + struct sk_buff *child = skb + 1; + atomic_t *fclone_ref = (atomic_t *) (child + 1); + + kmemcheck_annotate_bitfield(child, flags1); + kmemcheck_annotate_bitfield(child, flags2); + skb->fclone = SKB_FCLONE_ORIG; + atomic_set(fclone_ref, 1); + + child->fclone = SKB_FCLONE_UNAVAILABLE; + } +out: + return skb; +nodata: + kmem_cache_free(cache, skb); + skb = NULL; + goto out; +} +EXPORT_SYMBOL(__alloc_skb); + +/** + * __netdev_alloc_skb - allocate an skbuff for rx on a specific device + * @dev: network device to receive on + * @length: length to allocate + * @gfp_mask: get_free_pages mask, passed to alloc_skb + * + * Allocate a new &sk_buff and assign it a usage count of one. The + * buffer has unspecified headroom built in. Users should allocate + * the headroom they think they need without accounting for the + * built in space. The built in space is used for optimisations. + * + * %NULL is returned if there is no free memory. + */ +struct sk_buff *__netdev_alloc_skb(struct net_device *dev, + unsigned int length, gfp_t gfp_mask) +{ + struct sk_buff *skb; + + skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, NUMA_NO_NODE); + if (likely(skb)) { + skb_reserve(skb, NET_SKB_PAD); + skb->dev = dev; + } + return skb; +} +EXPORT_SYMBOL(__netdev_alloc_skb); + +void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off, + int size) +{ + skb_fill_page_desc(skb, i, page, off, size); + skb->len += size; + skb->data_len += size; + skb->truesize += size; +} +EXPORT_SYMBOL(skb_add_rx_frag); + +/** + * dev_alloc_skb - allocate an skbuff for receiving + * @length: length to allocate + * + * Allocate a new &sk_buff and assign it a usage count of one. The + * buffer has unspecified headroom built in. Users should allocate + * the headroom they think they need without accounting for the + * built in space. The built in space is used for optimisations. + * + * %NULL is returned if there is no free memory. Although this function + * allocates memory it can be called from an interrupt. + */ +struct sk_buff *dev_alloc_skb(unsigned int length) +{ + /* + * There is more code here than it seems: + * __dev_alloc_skb is an inline + */ + return __dev_alloc_skb(length, GFP_ATOMIC); +} +EXPORT_SYMBOL(dev_alloc_skb); + +static void skb_drop_list(struct sk_buff **listp) +{ + struct sk_buff *list = *listp; + + *listp = NULL; + + do { + struct sk_buff *this = list; + list = list->next; + kfree_skb(this); + } while (list); +} + +static inline void skb_drop_fraglist(struct sk_buff *skb) +{ + skb_drop_list(&skb_shinfo(skb)->frag_list); +} + +static void skb_clone_fraglist(struct sk_buff *skb) +{ + struct sk_buff *list; + + skb_walk_frags(skb, list) + skb_get(list); +} + +static void skb_release_data(struct sk_buff *skb) +{ + if (!skb->cloned || + !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1, + &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_has_frag_list(skb)) + skb_drop_fraglist(skb); + + kfree(skb->head); + } +} + +/* + * Free an skbuff by memory without cleaning the state. + */ +static void kfree_skbmem(struct sk_buff *skb) +{ + struct sk_buff *other; + atomic_t *fclone_ref; + + switch (skb->fclone) { + case SKB_FCLONE_UNAVAILABLE: + kmem_cache_free(skbuff_head_cache, skb); + break; + + case SKB_FCLONE_ORIG: + fclone_ref = (atomic_t *) (skb + 2); + if (atomic_dec_and_test(fclone_ref)) + kmem_cache_free(skbuff_fclone_cache, skb); + break; + + case SKB_FCLONE_CLONE: + fclone_ref = (atomic_t *) (skb + 1); + other = skb - 1; + + /* The clone portion is available for + * fast-cloning again. + */ + skb->fclone = SKB_FCLONE_UNAVAILABLE; + + if (atomic_dec_and_test(fclone_ref)) + kmem_cache_free(skbuff_fclone_cache, other); + break; + } +} + +static void skb_release_head_state(struct sk_buff *skb) +{ + skb_dst_drop(skb); +#ifdef CONFIG_XFRM + secpath_put(skb->sp); +#endif + if (skb->destructor) { + WARN_ON(in_irq()); + skb->destructor(skb); + } +#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) + nf_conntrack_put(skb->nfct); +#endif +#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED + nf_conntrack_put_reasm(skb->nfct_reasm); +#endif +#ifdef CONFIG_BRIDGE_NETFILTER + nf_bridge_put(skb->nf_bridge); +#endif +/* XXX: IS this still necessary? - JHS */ +#ifdef CONFIG_NET_SCHED + skb->tc_index = 0; +#ifdef CONFIG_NET_CLS_ACT + skb->tc_verd = 0; +#endif +#endif +} + +/* Free everything but the sk_buff shell. */ +static void skb_release_all(struct sk_buff *skb) +{ + skb_release_head_state(skb); + skb_release_data(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) +{ + skb_release_all(skb); + kfree_skbmem(skb); +} +EXPORT_SYMBOL(__kfree_skb); + +/** + * kfree_skb - free an sk_buff + * @skb: buffer to free + * + * Drop a reference to the buffer and free it if the usage count has + * hit zero. + */ +void kfree_skb(struct sk_buff *skb) +{ + if (unlikely(!skb)) + return; + if (likely(atomic_read(&skb->users) == 1)) + smp_rmb(); + else if (likely(!atomic_dec_and_test(&skb->users))) + return; + trace_kfree_skb(skb, __builtin_return_address(0)); + __kfree_skb(skb); +} +EXPORT_SYMBOL(kfree_skb); + +/** + * consume_skb - free an skbuff + * @skb: buffer to free + * + * Drop a ref to the buffer and free it if the usage count has hit zero + * Functions identically to kfree_skb, but kfree_skb assumes that the frame + * is being dropped after a failure and notes that + */ +void consume_skb(struct sk_buff *skb) +{ + if (unlikely(!skb)) + return; + if (likely(atomic_read(&skb->users) == 1)) + smp_rmb(); + else if (likely(!atomic_dec_and_test(&skb->users))) + return; + trace_consume_skb(skb); + __kfree_skb(skb); +} +EXPORT_SYMBOL(consume_skb); + +/** + * skb_recycle_check - check if skb can be reused for receive + * @skb: buffer + * @skb_size: minimum receive buffer size + * + * Checks that the skb passed in is not shared or cloned, and + * that it is linear and its head portion at least as large as + * skb_size so that it can be recycled as a receive buffer. + * If these conditions are met, this function does any necessary + * reference count dropping and cleans up the skbuff as if it + * just came from __alloc_skb(). + */ +bool skb_recycle_check(struct sk_buff *skb, int skb_size) +{ + struct skb_shared_info *shinfo; + + if (irqs_disabled()) + return false; + + if (skb_is_nonlinear(skb) || skb->fclone != SKB_FCLONE_UNAVAILABLE) + return false; + + skb_size = SKB_DATA_ALIGN(skb_size + NET_SKB_PAD); + if (skb_end_pointer(skb) - skb->head < skb_size) + return false; + + if (skb_shared(skb) || skb_cloned(skb)) + return false; + + skb_release_head_state(skb); + + shinfo = skb_shinfo(skb); + memset(shinfo, 0, offsetof(struct skb_shared_info, dataref)); + atomic_set(&shinfo->dataref, 1); + + memset(skb, 0, offsetof(struct sk_buff, tail)); + skb->data = skb->head + NET_SKB_PAD; + skb_reset_tail_pointer(skb); + + return true; +} +EXPORT_SYMBOL(skb_recycle_check); + +static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old) +{ + new->tstamp = old->tstamp; + new->dev = old->dev; + new->transport_header = old->transport_header; + new->network_header = old->network_header; + new->mac_header = old->mac_header; + skb_dst_copy(new, old); + new->rxhash = old->rxhash; +#ifdef CONFIG_XFRM + new->sp = secpath_get(old->sp); +#endif + memcpy(new->cb, old->cb, sizeof(old->cb)); + new->csum = old->csum; + new->local_df = old->local_df; + new->pkt_type = old->pkt_type; + new->ip_summed = old->ip_summed; + skb_copy_queue_mapping(new, old); + new->priority = old->priority; +#if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) + new->ipvs_property = old->ipvs_property; +#endif + new->protocol = old->protocol; + new->mark = old->mark; + new->skb_iif = old->skb_iif; + __nf_copy(new, old); +#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ + defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) + new->nf_trace = old->nf_trace; +#endif +#ifdef CONFIG_NET_SCHED + new->tc_index = old->tc_index; +#ifdef CONFIG_NET_CLS_ACT + new->tc_verd = old->tc_verd; +#endif +#endif + new->vlan_tci = old->vlan_tci; + + skb_copy_secmark(new, old); +} + +/* + * You should not add any new code to this function. Add it to + * __copy_skb_header above instead. + */ +static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb) +{ +#define C(x) n->x = skb->x + + n->next = n->prev = NULL; + n->sk = NULL; + __copy_skb_header(n, skb); + + C(len); + C(data_len); + C(mac_len); + n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len; + n->cloned = 1; + n->nohdr = 0; + n->destructor = NULL; + C(tail); + C(end); + C(head); + C(data); + C(truesize); + atomic_set(&n->users, 1); + + atomic_inc(&(skb_shinfo(skb)->dataref)); + skb->cloned = 1; + + return n; +#undef C +} + +/** + * skb_morph - morph one skb into another + * @dst: the skb to receive the contents + * @src: the skb to supply the contents + * + * This is identical to skb_clone except that the target skb is + * supplied by the user. + * + * The target skb is returned upon exit. + */ +struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src) +{ + skb_release_all(dst); + return __skb_clone(dst, src); +} +EXPORT_SYMBOL_GPL(skb_morph); + +/** + * 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, gfp_t gfp_mask) +{ + struct sk_buff *n; + + n = skb + 1; + if (skb->fclone == SKB_FCLONE_ORIG && + n->fclone == SKB_FCLONE_UNAVAILABLE) { + atomic_t *fclone_ref = (atomic_t *) (n + 1); + n->fclone = SKB_FCLONE_CLONE; + atomic_inc(fclone_ref); + } else { + n = kmem_cache_alloc(skbuff_head_cache, gfp_mask); + if (!n) + return NULL; + + kmemcheck_annotate_bitfield(n, flags1); + kmemcheck_annotate_bitfield(n, flags2); + n->fclone = SKB_FCLONE_UNAVAILABLE; + } + + return __skb_clone(n, skb); +} +EXPORT_SYMBOL(skb_clone); + +static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old) +{ +#ifndef NET_SKBUFF_DATA_USES_OFFSET + /* + * Shift between the two data areas in bytes + */ + unsigned long offset = new->data - old->data; +#endif + + __copy_skb_header(new, old); + +#ifndef NET_SKBUFF_DATA_USES_OFFSET + /* {transport,network,mac}_header are relative to skb->head */ + new->transport_header += offset; + new->network_header += offset; + if (skb_mac_header_was_set(new)) + new->mac_header += offset; +#endif + skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size; + skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs; + skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type; +} + +/** + * 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, gfp_t gfp_mask) +{ + int headerlen = skb_headroom(skb); + unsigned int size = (skb_end_pointer(skb) - skb->head) + skb->data_len; + struct sk_buff *n = alloc_skb(size, 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); + + if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len)) + BUG(); + + copy_skb_header(n, skb); + return n; +} +EXPORT_SYMBOL(skb_copy); + +/** + * 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, gfp_t gfp_mask) +{ + unsigned int size = skb_end_pointer(skb) - skb->head; + struct sk_buff *n = alloc_skb(size, gfp_mask); + + if (!n) + goto out; + + /* Set the data pointer */ + skb_reserve(n, skb_headroom(skb)); + /* Set the tail pointer and length */ + skb_put(n, skb_headlen(skb)); + /* Copy the bytes */ + skb_copy_from_linear_data(skb, n->data, n->len); + + n->truesize += skb->data_len; + 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_has_frag_list(skb)) { + skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list; + skb_clone_fraglist(n); + } + + copy_skb_header(n, skb); +out: + return n; +} +EXPORT_SYMBOL(pskb_copy); + +/** + * 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, + gfp_t gfp_mask) +{ + int i; + u8 *data; + int size = nhead + (skb_end_pointer(skb) - skb->head) + ntail; + long off; + bool fastpath; + + BUG_ON(nhead < 0); + + if (skb_shared(skb)) + BUG(); + + size = SKB_DATA_ALIGN(size); + + /* Check if we can avoid taking references on fragments if we own + * the last reference on skb->head. (see skb_release_data()) + */ + if (!skb->cloned) + fastpath = true; + else { + int delta = skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1; + + fastpath = atomic_read(&skb_shinfo(skb)->dataref) == delta; + } + + if (fastpath && + size + sizeof(struct skb_shared_info) <= ksize(skb->head)) { + memmove(skb->head + size, skb_shinfo(skb), + offsetof(struct skb_shared_info, + frags[skb_shinfo(skb)->nr_frags])); + memmove(skb->head + nhead, skb->head, + skb_tail_pointer(skb) - skb->head); + off = nhead; + goto adjust_others; + } + + 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_pointer(skb) - skb->head); + + memcpy((struct skb_shared_info *)(data + size), + skb_shinfo(skb), + offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags])); + + if (fastpath) { + kfree(skb->head); + } else { + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) + get_page(skb_shinfo(skb)->frags[i].page); + + if (skb_has_frag_list(skb)) + skb_clone_fraglist(skb); + + skb_release_data(skb); + } + off = (data + nhead) - skb->head; + + skb->head = data; +adjust_others: + skb->data += off; +#ifdef NET_SKBUFF_DATA_USES_OFFSET + skb->end = size; + off = nhead; +#else + skb->end = skb->head + size; +#endif + /* {transport,network,mac}_header and tail are relative to skb->head */ + skb->tail += off; + skb->transport_header += off; + skb->network_header += off; + if (skb_mac_header_was_set(skb)) + skb->mac_header += off; + /* Only adjust this if it actually is csum_start rather than csum */ + if (skb->ip_summed == CHECKSUM_PARTIAL) + skb->csum_start += nhead; + skb->cloned = 0; + skb->hdr_len = 0; + skb->nohdr = 0; + atomic_set(&skb_shinfo(skb)->dataref, 1); + return 0; + +nodata: + return -ENOMEM; +} +EXPORT_SYMBOL(pskb_expand_head); + +/* 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; +} +EXPORT_SYMBOL(skb_realloc_headroom); + +/** + * 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, + gfp_t gfp_mask) +{ + /* + * Allocate the copy buffer + */ + struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom, + gfp_mask); + int oldheadroom = skb_headroom(skb); + int head_copy_len, head_copy_off; + int off; + + if (!n) + return NULL; + + skb_reserve(n, newheadroom); + + /* Set the tail pointer and length */ + skb_put(n, skb->len); + + head_copy_len = oldheadroom; + 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); + + off = newheadroom - oldheadroom; + if (n->ip_summed == CHECKSUM_PARTIAL) + n->csum_start += off; +#ifdef NET_SKBUFF_DATA_USES_OFFSET + n->transport_header += off; + n->network_header += off; + if (skb_mac_header_was_set(skb)) + n->mac_header += off; +#endif + + return n; +} +EXPORT_SYMBOL(skb_copy_expand); + +/** + * 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 error in out of memory cases. The skb is freed on error. + */ + +int skb_pad(struct sk_buff *skb, int pad) +{ + int err; + int ntail; + + /* If the skbuff is non linear tailroom is always zero.. */ + if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) { + memset(skb->data+skb->len, 0, pad); + return 0; + } + + ntail = skb->data_len + pad - (skb->end - skb->tail); + if (likely(skb_cloned(skb) || ntail > 0)) { + err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC); + if (unlikely(err)) + goto free_skb; + } + + /* FIXME: The use of this function with non-linear skb's really needs + * to be audited. + */ + err = skb_linearize(skb); + if (unlikely(err)) + goto free_skb; + + memset(skb->data + skb->len, 0, pad); + return 0; + +free_skb: + kfree_skb(skb); + return err; +} +EXPORT_SYMBOL(skb_pad); + +/** + * skb_put - add data to a buffer + * @skb: buffer to use + * @len: amount of data to add + * + * This function extends the used data area of the buffer. If this would + * exceed the total buffer size the kernel will panic. A pointer to the + * first byte of the extra data is returned. + */ +unsigned char *skb_put(struct sk_buff *skb, unsigned int len) +{ + unsigned char *tmp = skb_tail_pointer(skb); + SKB_LINEAR_ASSERT(skb); + skb->tail += len; + skb->len += len; + if (unlikely(skb->tail > skb->end)) + skb_over_panic(skb, len, __builtin_return_address(0)); + return tmp; +} +EXPORT_SYMBOL(skb_put); + +/** + * skb_push - add data to the start of a buffer + * @skb: buffer to use + * @len: amount of data to add + * + * This function extends the used data area of the buffer at the buffer + * start. If this would exceed the total buffer headroom the kernel will + * panic. A pointer to the first byte of the extra data is returned. + */ +unsigned char *skb_push(struct sk_buff *skb, unsigned int len) +{ + skb->data -= len; + skb->len += len; + if (unlikely(skb->data<skb->head)) + skb_under_panic(skb, len, __builtin_return_address(0)); + return skb->data; +} +EXPORT_SYMBOL(skb_push); + +/** + * skb_pull - remove data from the start of a buffer + * @skb: buffer to use + * @len: amount of data to remove + * + * This function removes data from the start of a buffer, returning + * the memory to the headroom. A pointer to the next data in the buffer + * is returned. Once the data has been pulled future pushes will overwrite + * the old data. + */ +unsigned char *skb_pull(struct sk_buff *skb, unsigned int len) +{ + return skb_pull_inline(skb, len); +} +EXPORT_SYMBOL(skb_pull); + +/** + * skb_trim - remove end from a buffer + * @skb: buffer to alter + * @len: new length + * + * Cut the length of a buffer down by removing data from the tail. If + * the buffer is already under the length specified it is not modified. + * The skb must be linear. + */ +void skb_trim(struct sk_buff *skb, unsigned int len) +{ + if (skb->len > len) + __skb_trim(skb, len); +} +EXPORT_SYMBOL(skb_trim); + +/* Trims skb to length len. It can change skb pointers. + */ + +int ___pskb_trim(struct sk_buff *skb, unsigned int len) +{ + struct sk_buff **fragp; + struct sk_buff *frag; + int offset = skb_headlen(skb); + int nfrags = skb_shinfo(skb)->nr_frags; + int i; + int err; + + if (skb_cloned(skb) && + unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))) + return err; + + i = 0; + if (offset >= len) + goto drop_pages; + + for (; i < nfrags; i++) { + int end = offset + skb_shinfo(skb)->frags[i].size; + + if (end < len) { + offset = end; + continue; + } + + skb_shinfo(skb)->frags[i++].size = len - offset; + +drop_pages: + skb_shinfo(skb)->nr_frags = i; + + for (; i < nfrags; i++) + put_page(skb_shinfo(skb)->frags[i].page); + + if (skb_has_frag_list(skb)) + skb_drop_fraglist(skb); + goto done; + } + + for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp); + fragp = &frag->next) { + int end = offset + frag->len; + + if (skb_shared(frag)) { + struct sk_buff *nfrag; + + nfrag = skb_clone(frag, GFP_ATOMIC); + if (unlikely(!nfrag)) + return -ENOMEM; + + nfrag->next = frag->next; + kfree_skb(frag); + frag = nfrag; + *fragp = frag; + } + + if (end < len) { + offset = end; + continue; + } + + if (end > len && + unlikely((err = pskb_trim(frag, len - offset)))) + return err; + + if (frag->next) + skb_drop_list(&frag->next); + break; + } + +done: + if (len > skb_headlen(skb)) { + skb->data_len -= skb->len - len; + skb->len = len; + } else { + skb->len = len; + skb->data_len = 0; + skb_set_tail_pointer(skb, len); + } + + return 0; +} +EXPORT_SYMBOL(___pskb_trim); + +/** + * __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_pointer(skb), delta)) + BUG(); + + /* Optimization: no fragments, no reasons to preestimate + * size of pulled pages. Superb. + */ + if (!skb_has_frag_list(skb)) + 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 { + BUG_ON(!list); + + 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)) { + 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_pointer(skb); +} +EXPORT_SYMBOL(__pskb_pull_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 start = skb_headlen(skb); + struct sk_buff *frag_iter; + int i, copy; + + if (offset > (int)skb->len - len) + goto fault; + + /* Copy header. */ + if ((copy = start - offset) > 0) { + if (copy > len) + copy = len; + skb_copy_from_linear_data_offset(skb, offset, to, copy); + if ((len -= copy) == 0) + return 0; + offset += copy; + to += copy; + } + + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + int end; + + WARN_ON(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; + } + + skb_walk_frags(skb, frag_iter) { + int end; + + WARN_ON(start > offset + len); + + end = start + frag_iter->len; + if ((copy = end - offset) > 0) { + if (copy > len) + copy = len; + if (skb_copy_bits(frag_iter, 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; +} +EXPORT_SYMBOL(skb_copy_bits); + +/* + * Callback from splice_to_pipe(), if we need to release some pages + * at the end of the spd in case we error'ed out in filling the pipe. + */ +static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i) +{ + put_page(spd->pages[i]); +} + +static inline struct page *linear_to_page(struct page *page, unsigned int *len, + unsigned int *offset, + struct sk_buff *skb, struct sock *sk) +{ + struct page *p = sk->sk_sndmsg_page; + unsigned int off; + + if (!p) { +new_page: + p = sk->sk_sndmsg_page = alloc_pages(sk->sk_allocation, 0); + if (!p) + return NULL; + + off = sk->sk_sndmsg_off = 0; + /* hold one ref to this page until it's full */ + } else { + unsigned int mlen; + + off = sk->sk_sndmsg_off; + mlen = PAGE_SIZE - off; + if (mlen < 64 && mlen < *len) { + put_page(p); + goto new_page; + } + + *len = min_t(unsigned int, *len, mlen); + } + + memcpy(page_address(p) + off, page_address(page) + *offset, *len); + sk->sk_sndmsg_off += *len; + *offset = off; + get_page(p); + + return p; +} + +/* + * Fill page/offset/length into spd, if it can hold more pages. + */ +static inline int spd_fill_page(struct splice_pipe_desc *spd, + struct pipe_inode_info *pipe, struct page *page, + unsigned int *len, unsigned int offset, + struct sk_buff *skb, int linear, + struct sock *sk) +{ + if (unlikely(spd->nr_pages == pipe->buffers)) + return 1; + + if (linear) { + page = linear_to_page(page, len, &offset, skb, sk); + if (!page) + return 1; + } else + get_page(page); + + spd->pages[spd->nr_pages] = page; + spd->partial[spd->nr_pages].len = *len; + spd->partial[spd->nr_pages].offset = offset; + spd->nr_pages++; + + return 0; +} + +static inline void __segment_seek(struct page **page, unsigned int *poff, + unsigned int *plen, unsigned int off) +{ + unsigned long n; + + *poff += off; + n = *poff / PAGE_SIZE; + if (n) + *page = nth_page(*page, n); + + *poff = *poff % PAGE_SIZE; + *plen -= off; +} + +static inline int __splice_segment(struct page *page, unsigned int poff, + unsigned int plen, unsigned int *off, + unsigned int *len, struct sk_buff *skb, + struct splice_pipe_desc *spd, int linear, + struct sock *sk, + struct pipe_inode_info *pipe) +{ + if (!*len) + return 1; + + /* skip this segment if already processed */ + if (*off >= plen) { + *off -= plen; + return 0; + } + + /* ignore any bits we already processed */ + if (*off) { + __segment_seek(&page, &poff, &plen, *off); + *off = 0; + } + + do { + unsigned int flen = min(*len, plen); + + /* the linear region may spread across several pages */ + flen = min_t(unsigned int, flen, PAGE_SIZE - poff); + + if (spd_fill_page(spd, pipe, page, &flen, poff, skb, linear, sk)) + return 1; + + __segment_seek(&page, &poff, &plen, flen); + *len -= flen; + + } while (*len && plen); + + return 0; +} + +/* + * Map linear and fragment data from the skb to spd. It reports failure if the + * pipe is full or if we already spliced the requested length. + */ +static int __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe, + unsigned int *offset, unsigned int *len, + struct splice_pipe_desc *spd, struct sock *sk) +{ + int seg; + + /* + * map the linear part + */ + if (__splice_segment(virt_to_page(skb->data), + (unsigned long) skb->data & (PAGE_SIZE - 1), + skb_headlen(skb), + offset, len, skb, spd, 1, sk, pipe)) + return 1; + + /* + * then map the fragments + */ + for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) { + const skb_frag_t *f = &skb_shinfo(skb)->frags[seg]; + + if (__splice_segment(f->page, f->page_offset, f->size, + offset, len, skb, spd, 0, sk, pipe)) + return 1; + } + + return 0; +} + +/* + * Map data from the skb to a pipe. Should handle both the linear part, + * the fragments, and the frag list. It does NOT handle frag lists within + * the frag list, if such a thing exists. We'd probably need to recurse to + * handle that cleanly. + */ +int skb_splice_bits(struct sk_buff *skb, unsigned int offset, + struct pipe_inode_info *pipe, unsigned int tlen, + unsigned int flags) +{ + struct partial_page partial[PIPE_DEF_BUFFERS]; + struct page *pages[PIPE_DEF_BUFFERS]; + struct splice_pipe_desc spd = { + .pages = pages, + .partial = partial, + .flags = flags, + .ops = &sock_pipe_buf_ops, + .spd_release = sock_spd_release, + }; + struct sk_buff *frag_iter; + struct sock *sk = skb->sk; + int ret = 0; + + if (splice_grow_spd(pipe, &spd)) + return -ENOMEM; + + /* + * __skb_splice_bits() only fails if the output has no room left, + * so no point in going over the frag_list for the error case. + */ + if (__skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk)) + goto done; + else if (!tlen) + goto done; + + /* + * now see if we have a frag_list to map + */ + skb_walk_frags(skb, frag_iter) { + if (!tlen) + break; + if (__skb_splice_bits(frag_iter, pipe, &offset, &tlen, &spd, sk)) + break; + } + +done: + if (spd.nr_pages) { + /* + * Drop the socket lock, otherwise we have reverse + * locking dependencies between sk_lock and i_mutex + * here as compared to sendfile(). We enter here + * with the socket lock held, and splice_to_pipe() will + * grab the pipe inode lock. For sendfile() emulation, + * we call into ->sendpage() with the i_mutex lock held + * and networking will grab the socket lock. + */ + release_sock(sk); + ret = splice_to_pipe(pipe, &spd); + lock_sock(sk); + } + + splice_shrink_spd(pipe, &spd); + return ret; +} + +/** + * skb_store_bits - store bits from kernel buffer to skb + * @skb: destination buffer + * @offset: offset in destination + * @from: source buffer + * @len: number of bytes to copy + * + * Copy the specified number of bytes from the source buffer to the + * destination skb. This function handles all the messy bits of + * traversing fragment lists and such. + */ + +int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len) +{ + int start = skb_headlen(skb); + struct sk_buff *frag_iter; + int i, copy; + + if (offset > (int)skb->len - len) + goto fault; + + if ((copy = start - offset) > 0) { + if (copy > len) + copy = len; + skb_copy_to_linear_data_offset(skb, offset, from, copy); + if ((len -= copy) == 0) + return 0; + offset += copy; + from += copy; + } + + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + int end; + + WARN_ON(start > offset + len); + + end = start + frag->size; + if ((copy = end - offset) > 0) { + u8 *vaddr; + + if (copy > len) + copy = len; + + vaddr = kmap_skb_frag(frag); + memcpy(vaddr + frag->page_offset + offset - start, + from, copy); + kunmap_skb_frag(vaddr); + + if ((len -= copy) == 0) + return 0; + offset += copy; + from += copy; + } + start = end; + } + + skb_walk_frags(skb, frag_iter) { + int end; + + WARN_ON(start > offset + len); + + end = start + frag_iter->len; + if ((copy = end - offset) > 0) { + if (copy > len) + copy = len; + if (skb_store_bits(frag_iter, offset - start, + from, copy)) + goto fault; + if ((len -= copy) == 0) + return 0; + offset += copy; + from += copy; + } + start = end; + } + if (!len) + return 0; + +fault: + return -EFAULT; +} +EXPORT_SYMBOL(skb_store_bits); + +/* Checksum skb data. */ + +__wsum skb_checksum(const struct sk_buff *skb, int offset, + int len, __wsum csum) +{ + int start = skb_headlen(skb); + int i, copy = start - offset; + struct sk_buff *frag_iter; + 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; + + WARN_ON(start > offset + len); + + end = start + skb_shinfo(skb)->frags[i].size; + if ((copy = end - offset) > 0) { + __wsum 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; + } + + skb_walk_frags(skb, frag_iter) { + int end; + + WARN_ON(start > offset + len); + + end = start + frag_iter->len; + if ((copy = end - offset) > 0) { + __wsum csum2; + if (copy > len) + copy = len; + csum2 = skb_checksum(frag_iter, offset - start, + copy, 0); + csum = csum_block_add(csum, csum2, pos); + if ((len -= copy) == 0) + return csum; + offset += copy; + pos += copy; + } + start = end; + } + BUG_ON(len); + + return csum; +} +EXPORT_SYMBOL(skb_checksum); + +/* Both of above in one bottle. */ + +__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, + u8 *to, int len, __wsum csum) +{ + int start = skb_headlen(skb); + int i, copy = start - offset; + struct sk_buff *frag_iter; + 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; + + WARN_ON(start > offset + len); + + end = start + skb_shinfo(skb)->frags[i].size; + if ((copy = end - offset) > 0) { + __wsum 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; + } + + skb_walk_frags(skb, frag_iter) { + __wsum csum2; + int end; + + WARN_ON(start > offset + len); + + end = start + frag_iter->len; + if ((copy = end - offset) > 0) { + if (copy > len) + copy = len; + csum2 = skb_copy_and_csum_bits(frag_iter, + 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; + } + BUG_ON(len); + return csum; +} +EXPORT_SYMBOL(skb_copy_and_csum_bits); + +void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to) +{ + __wsum csum; + long csstart; + + if (skb->ip_summed == CHECKSUM_PARTIAL) + csstart = skb_checksum_start_offset(skb); + else + csstart = skb_headlen(skb); + + BUG_ON(csstart > skb_headlen(skb)); + + skb_copy_from_linear_data(skb, to, 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_PARTIAL) { + long csstuff = csstart + skb->csum_offset; + + *((__sum16 *)(to + csstuff)) = csum_fold(csum); + } +} +EXPORT_SYMBOL(skb_copy_and_csum_dev); + +/** + * 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; +} +EXPORT_SYMBOL(skb_dequeue); + +/** + * 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; +} +EXPORT_SYMBOL(skb_dequeue_tail); + +/** + * 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); +} +EXPORT_SYMBOL(skb_queue_purge); + +/** + * 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); +} +EXPORT_SYMBOL(skb_queue_head); + +/** + * 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); +} +EXPORT_SYMBOL(skb_queue_tail); + +/** + * skb_unlink - remove a buffer from a list + * @skb: buffer to remove + * @list: list to use + * + * Remove a packet from a list. The list locks are taken and this + * function is atomic with respect to other list locked calls + * + * You must know what list the SKB is on. + */ +void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list) +{ + unsigned long flags; + + spin_lock_irqsave(&list->lock, flags); + __skb_unlink(skb, list); + spin_unlock_irqrestore(&list->lock, flags); +} +EXPORT_SYMBOL(skb_unlink); + +/** + * skb_append - append a buffer + * @old: buffer to insert after + * @newsk: buffer to insert + * @list: list to use + * + * 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, struct sk_buff_head *list) +{ + unsigned long flags; + + spin_lock_irqsave(&list->lock, flags); + __skb_queue_after(list, old, newsk); + spin_unlock_irqrestore(&list->lock, flags); +} +EXPORT_SYMBOL(skb_append); + +/** + * skb_insert - insert a buffer + * @old: buffer to insert before + * @newsk: buffer to insert + * @list: list to use + * + * 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, struct sk_buff_head *list) +{ + unsigned long flags; + + spin_lock_irqsave(&list->lock, flags); + __skb_insert(newsk, old->prev, old, list); + spin_unlock_irqrestore(&list->lock, flags); +} +EXPORT_SYMBOL(skb_insert); + +static inline void skb_split_inside_header(struct sk_buff *skb, + struct sk_buff* skb1, + const u32 len, const int pos) +{ + int i; + + skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - 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_set_tail_pointer(skb, len); +} + +static inline void 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 two 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. + * @skb: the buffer to split + * @skb1: the buffer to receive the second part + * @len: new length for skb + */ +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); +} +EXPORT_SYMBOL(skb_split); + +/* Shifting from/to a cloned skb is a no-go. + * + * Caller cannot keep skb_shinfo related pointers past calling here! + */ +static int skb_prepare_for_shift(struct sk_buff *skb) +{ + return skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC); +} + +/** + * skb_shift - Shifts paged data partially from skb to another + * @tgt: buffer into which tail data gets added + * @skb: buffer from which the paged data comes from + * @shiftlen: shift up to this many bytes + * + * Attempts to shift up to shiftlen worth of bytes, which may be less than + * the length of the skb, from tgt to skb. Returns number bytes shifted. + * It's up to caller to free skb if everything was shifted. + * + * If @tgt runs out of frags, the whole operation is aborted. + * + * Skb cannot include anything else but paged data while tgt is allowed + * to have non-paged data as well. + * + * TODO: full sized shift could be optimized but that would need + * specialized skb free'er to handle frags without up-to-date nr_frags. + */ +int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen) +{ + int from, to, merge, todo; + struct skb_frag_struct *fragfrom, *fragto; + + BUG_ON(shiftlen > skb->len); + BUG_ON(skb_headlen(skb)); /* Would corrupt stream */ + + todo = shiftlen; + from = 0; + to = skb_shinfo(tgt)->nr_frags; + fragfrom = &skb_shinfo(skb)->frags[from]; + + /* Actual merge is delayed until the point when we know we can + * commit all, so that we don't have to undo partial changes + */ + if (!to || + !skb_can_coalesce(tgt, to, fragfrom->page, fragfrom->page_offset)) { + merge = -1; + } else { + merge = to - 1; + + todo -= fragfrom->size; + if (todo < 0) { + if (skb_prepare_for_shift(skb) || + skb_prepare_for_shift(tgt)) + return 0; + + /* All previous frag pointers might be stale! */ + fragfrom = &skb_shinfo(skb)->frags[from]; + fragto = &skb_shinfo(tgt)->frags[merge]; + + fragto->size += shiftlen; + fragfrom->size -= shiftlen; + fragfrom->page_offset += shiftlen; + + goto onlymerged; + } + + from++; + } + + /* Skip full, not-fitting skb to avoid expensive operations */ + if ((shiftlen == skb->len) && + (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to)) + return 0; + + if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt)) + return 0; + + while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) { + if (to == MAX_SKB_FRAGS) + return 0; + + fragfrom = &skb_shinfo(skb)->frags[from]; + fragto = &skb_shinfo(tgt)->frags[to]; + + if (todo >= fragfrom->size) { + *fragto = *fragfrom; + todo -= fragfrom->size; + from++; + to++; + + } else { + get_page(fragfrom->page); + fragto->page = fragfrom->page; + fragto->page_offset = fragfrom->page_offset; + fragto->size = todo; + + fragfrom->page_offset += todo; + fragfrom->size -= todo; + todo = 0; + + to++; + break; + } + } + + /* Ready to "commit" this state change to tgt */ + skb_shinfo(tgt)->nr_frags = to; + + if (merge >= 0) { + fragfrom = &skb_shinfo(skb)->frags[0]; + fragto = &skb_shinfo(tgt)->frags[merge]; + + fragto->size += fragfrom->size; + put_page(fragfrom->page); + } + + /* Reposition in the original skb */ + to = 0; + while (from < skb_shinfo(skb)->nr_frags) + skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++]; + skb_shinfo(skb)->nr_frags = to; + + BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags); + +onlymerged: + /* Most likely the tgt won't ever need its checksum anymore, skb on + * the other hand might need it if it needs to be resent + */ + tgt->ip_summed = CHECKSUM_PARTIAL; + skb->ip_summed = CHECKSUM_PARTIAL; + + /* Yak, is it really working this way? Some helper please? */ + skb->len -= shiftlen; + skb->data_len -= shiftlen; + skb->truesize -= shiftlen; + tgt->len += shiftlen; + tgt->data_len += shiftlen; + tgt->truesize += shiftlen; + + return shiftlen; +} + +/** + * skb_prepare_seq_read - Prepare a sequential read of skb data + * @skb: the buffer to read + * @from: lower offset of data to be read + * @to: upper offset of data to be read + * @st: state variable + * + * Initializes the specified state variable. Must be called before + * invoking skb_seq_read() for the first time. + */ +void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from, + unsigned int to, struct skb_seq_state *st) +{ + st->lower_offset = from; + st->upper_offset = to; + st->root_skb = st->cur_skb = skb; + st->frag_idx = st->stepped_offset = 0; + st->frag_data = NULL; +} +EXPORT_SYMBOL(skb_prepare_seq_read); + +/** + * skb_seq_read - Sequentially read skb data + * @consumed: number of bytes consumed by the caller so far + * @data: destination pointer for data to be returned + * @st: state variable + * + * Reads a block of skb data at &consumed relative to the + * lower offset specified to skb_prepare_seq_read(). Assigns + * the head of the data block to &data and returns the length + * of the block or 0 if the end of the skb data or the upper + * offset has been reached. + * + * The caller is not required to consume all of the data + * returned, i.e. &consumed is typically set to the number + * of bytes already consumed and the next call to + * skb_seq_read() will return the remaining part of the block. + * + * Note 1: The size of each block of data returned can be arbitrary, + * this limitation is the cost for zerocopy seqeuental + * reads of potentially non linear data. + * + * Note 2: Fragment lists within fragments are not implemented + * at the moment, state->root_skb could be replaced with + * a stack for this purpose. + */ +unsigned int skb_seq_read(unsigned int consumed, const u8 **data, + struct skb_seq_state *st) +{ + unsigned int block_limit, abs_offset = consumed + st->lower_offset; + skb_frag_t *frag; + + if (unlikely(abs_offset >= st->upper_offset)) + return 0; + +next_skb: + block_limit = skb_headlen(st->cur_skb) + st->stepped_offset; + + if (abs_offset < block_limit && !st->frag_data) { + *data = st->cur_skb->data + (abs_offset - st->stepped_offset); + return block_limit - abs_offset; + } + + if (st->frag_idx == 0 && !st->frag_data) + st->stepped_offset += skb_headlen(st->cur_skb); + + while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) { + frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx]; + block_limit = frag->size + st->stepped_offset; + + if (abs_offset < block_limit) { + if (!st->frag_data) + st->frag_data = kmap_skb_frag(frag); + + *data = (u8 *) st->frag_data + frag->page_offset + + (abs_offset - st->stepped_offset); + + return block_limit - abs_offset; + } + + if (st->frag_data) { + kunmap_skb_frag(st->frag_data); + st->frag_data = NULL; + } + + st->frag_idx++; + st->stepped_offset += frag->size; + } + + if (st->frag_data) { + kunmap_skb_frag(st->frag_data); + st->frag_data = NULL; + } + + if (st->root_skb == st->cur_skb && skb_has_frag_list(st->root_skb)) { + st->cur_skb = skb_shinfo(st->root_skb)->frag_list; + st->frag_idx = 0; + goto next_skb; + } else if (st->cur_skb->next) { + st->cur_skb = st->cur_skb->next; + st->frag_idx = 0; + goto next_skb; + } + + return 0; +} +EXPORT_SYMBOL(skb_seq_read); + +/** + * skb_abort_seq_read - Abort a sequential read of skb data + * @st: state variable + * + * Must be called if skb_seq_read() was not called until it + * returned 0. + */ +void skb_abort_seq_read(struct skb_seq_state *st) +{ + if (st->frag_data) + kunmap_skb_frag(st->frag_data); +} +EXPORT_SYMBOL(skb_abort_seq_read); + +#define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb)) + +static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text, + struct ts_config *conf, + struct ts_state *state) +{ + return skb_seq_read(offset, text, TS_SKB_CB(state)); +} + +static void skb_ts_finish(struct ts_config *conf, struct ts_state *state) +{ + skb_abort_seq_read(TS_SKB_CB(state)); +} + +/** + * skb_find_text - Find a text pattern in skb data + * @skb: the buffer to look in + * @from: search offset + * @to: search limit + * @config: textsearch configuration + * @state: uninitialized textsearch state variable + * + * Finds a pattern in the skb data according to the specified + * textsearch configuration. Use textsearch_next() to retrieve + * subsequent occurrences of the pattern. Returns the offset + * to the first occurrence or UINT_MAX if no match was found. + */ +unsigned int skb_find_text(struct sk_buff *skb, unsigned int from, + unsigned int to, struct ts_config *config, + struct ts_state *state) +{ + unsigned int ret; + + config->get_next_block = skb_ts_get_next_block; + config->finish = skb_ts_finish; + + skb_prepare_seq_read(skb, from, to, TS_SKB_CB(state)); + + ret = textsearch_find(config, state); + return (ret <= to - from ? ret : UINT_MAX); +} +EXPORT_SYMBOL(skb_find_text); + +/** + * skb_append_datato_frags: - append the user data to a skb + * @sk: sock structure + * @skb: skb structure to be appened with user data. + * @getfrag: call back function to be used for getting the user data + * @from: pointer to user message iov + * @length: length of the iov message + * + * Description: This procedure append the user data in the fragment part + * of the skb if any page alloc fails user this procedure returns -ENOMEM + */ +int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb, + int (*getfrag)(void *from, char *to, int offset, + int len, int odd, struct sk_buff *skb), + void *from, int length) +{ + int frg_cnt = 0; + skb_frag_t *frag = NULL; + struct page *page = NULL; + int copy, left; + int offset = 0; + int ret; + + do { + /* Return error if we don't have space for new frag */ + frg_cnt = skb_shinfo(skb)->nr_frags; + if (frg_cnt >= MAX_SKB_FRAGS) + return -EFAULT; + + /* allocate a new page for next frag */ + page = alloc_pages(sk->sk_allocation, 0); + + /* If alloc_page fails just return failure and caller will + * free previous allocated pages by doing kfree_skb() + */ + if (page == NULL) + return -ENOMEM; + + /* initialize the next frag */ + skb_fill_page_desc(skb, frg_cnt, page, 0, 0); + skb->truesize += PAGE_SIZE; + atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); + + /* get the new initialized frag */ + frg_cnt = skb_shinfo(skb)->nr_frags; + frag = &skb_shinfo(skb)->frags[frg_cnt - 1]; + + /* copy the user data to page */ + left = PAGE_SIZE - frag->page_offset; + copy = (length > left)? left : length; + + ret = getfrag(from, (page_address(frag->page) + + frag->page_offset + frag->size), + offset, copy, 0, skb); + if (ret < 0) + return -EFAULT; + + /* copy was successful so update the size parameters */ + frag->size += copy; + skb->len += copy; + skb->data_len += copy; + offset += copy; + length -= copy; + + } while (length > 0); + + return 0; +} +EXPORT_SYMBOL(skb_append_datato_frags); + +/** + * skb_pull_rcsum - pull skb and update receive checksum + * @skb: buffer to update + * @len: length of data pulled + * + * This function performs an skb_pull on the packet and updates + * the CHECKSUM_COMPLETE checksum. It should be used on + * receive path processing instead of skb_pull unless you know + * that the checksum difference is zero (e.g., a valid IP header) + * or you are setting ip_summed to CHECKSUM_NONE. + */ +unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len) +{ + BUG_ON(len > skb->len); + skb->len -= len; + BUG_ON(skb->len < skb->data_len); + skb_postpull_rcsum(skb, skb->data, len); + return skb->data += len; +} +EXPORT_SYMBOL_GPL(skb_pull_rcsum); + +/** + * skb_segment - Perform protocol segmentation on skb. + * @skb: buffer to segment + * @features: features for the output path (see dev->features) + * + * This function performs segmentation on the given skb. It returns + * a pointer to the first in a list of new skbs for the segments. + * In case of error it returns ERR_PTR(err). + */ +struct sk_buff *skb_segment(struct sk_buff *skb, u32 features) +{ + struct sk_buff *segs = NULL; + struct sk_buff *tail = NULL; + struct sk_buff *fskb = skb_shinfo(skb)->frag_list; + unsigned int mss = skb_shinfo(skb)->gso_size; + unsigned int doffset = skb->data - skb_mac_header(skb); + unsigned int offset = doffset; + unsigned int headroom; + unsigned int len; + int sg = !!(features & NETIF_F_SG); + int nfrags = skb_shinfo(skb)->nr_frags; + int err = -ENOMEM; + int i = 0; + int pos; + + __skb_push(skb, doffset); + headroom = skb_headroom(skb); + pos = skb_headlen(skb); + + do { + struct sk_buff *nskb; + skb_frag_t *frag; + int hsize; + int size; + + len = skb->len - offset; + if (len > mss) + len = mss; + + hsize = skb_headlen(skb) - offset; + if (hsize < 0) + hsize = 0; + if (hsize > len || !sg) + hsize = len; + + if (!hsize && i >= nfrags) { + BUG_ON(fskb->len != len); + + pos += len; + nskb = skb_clone(fskb, GFP_ATOMIC); + fskb = fskb->next; + + if (unlikely(!nskb)) + goto err; + + hsize = skb_end_pointer(nskb) - nskb->head; + if (skb_cow_head(nskb, doffset + headroom)) { + kfree_skb(nskb); + goto err; + } + + nskb->truesize += skb_end_pointer(nskb) - nskb->head - + hsize; + skb_release_head_state(nskb); + __skb_push(nskb, doffset); + } else { + nskb = alloc_skb(hsize + doffset + headroom, + GFP_ATOMIC); + + if (unlikely(!nskb)) + goto err; + + skb_reserve(nskb, headroom); + __skb_put(nskb, doffset); + } + + if (segs) + tail->next = nskb; + else + segs = nskb; + tail = nskb; + + __copy_skb_header(nskb, skb); + nskb->mac_len = skb->mac_len; + + /* nskb and skb might have different headroom */ + if (nskb->ip_summed == CHECKSUM_PARTIAL) + nskb->csum_start += skb_headroom(nskb) - headroom; + + skb_reset_mac_header(nskb); + skb_set_network_header(nskb, skb->mac_len); + nskb->transport_header = (nskb->network_header + + skb_network_header_len(skb)); + skb_copy_from_linear_data(skb, nskb->data, doffset); + + if (fskb != skb_shinfo(skb)->frag_list) + continue; + + if (!sg) { + nskb->ip_summed = CHECKSUM_NONE; + nskb->csum = skb_copy_and_csum_bits(skb, offset, + skb_put(nskb, len), + len, 0); + continue; + } + + frag = skb_shinfo(nskb)->frags; + + skb_copy_from_linear_data_offset(skb, offset, + skb_put(nskb, hsize), hsize); + + while (pos < offset + len && i < nfrags) { + *frag = skb_shinfo(skb)->frags[i]; + get_page(frag->page); + size = frag->size; + + if (pos < offset) { + frag->page_offset += offset - pos; + frag->size -= offset - pos; + } + + skb_shinfo(nskb)->nr_frags++; + + if (pos + size <= offset + len) { + i++; + pos += size; + } else { + frag->size -= pos + size - (offset + len); + goto skip_fraglist; + } + + frag++; + } + + if (pos < offset + len) { + struct sk_buff *fskb2 = fskb; + + BUG_ON(pos + fskb->len != offset + len); + + pos += fskb->len; + fskb = fskb->next; + + if (fskb2->next) { + fskb2 = skb_clone(fskb2, GFP_ATOMIC); + if (!fskb2) + goto err; + } else + skb_get(fskb2); + + SKB_FRAG_ASSERT(nskb); + skb_shinfo(nskb)->frag_list = fskb2; + } + +skip_fraglist: + nskb->data_len = len - hsize; + nskb->len += nskb->data_len; + nskb->truesize += nskb->data_len; + } while ((offset += len) < skb->len); + + return segs; + +err: + while ((skb = segs)) { + segs = skb->next; + kfree_skb(skb); + } + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(skb_segment); + +int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) +{ + struct sk_buff *p = *head; + struct sk_buff *nskb; + struct skb_shared_info *skbinfo = skb_shinfo(skb); + struct skb_shared_info *pinfo = skb_shinfo(p); + unsigned int headroom; + unsigned int len = skb_gro_len(skb); + unsigned int offset = skb_gro_offset(skb); + unsigned int headlen = skb_headlen(skb); + + if (p->len + len >= 65536) + return -E2BIG; + + if (pinfo->frag_list) + goto merge; + else if (headlen <= offset) { + skb_frag_t *frag; + skb_frag_t *frag2; + int i = skbinfo->nr_frags; + int nr_frags = pinfo->nr_frags + i; + + offset -= headlen; + + if (nr_frags > MAX_SKB_FRAGS) + return -E2BIG; + + pinfo->nr_frags = nr_frags; + skbinfo->nr_frags = 0; + + frag = pinfo->frags + nr_frags; + frag2 = skbinfo->frags + i; + do { + *--frag = *--frag2; + } while (--i); + + frag->page_offset += offset; + frag->size -= offset; + + skb->truesize -= skb->data_len; + skb->len -= skb->data_len; + skb->data_len = 0; + + NAPI_GRO_CB(skb)->free = 1; + goto done; + } else if (skb_gro_len(p) != pinfo->gso_size) + return -E2BIG; + + headroom = skb_headroom(p); + nskb = alloc_skb(headroom + skb_gro_offset(p), GFP_ATOMIC); + if (unlikely(!nskb)) + return -ENOMEM; + + __copy_skb_header(nskb, p); + nskb->mac_len = p->mac_len; + + skb_reserve(nskb, headroom); + __skb_put(nskb, skb_gro_offset(p)); + + skb_set_mac_header(nskb, skb_mac_header(p) - p->data); + skb_set_network_header(nskb, skb_network_offset(p)); + skb_set_transport_header(nskb, skb_transport_offset(p)); + + __skb_pull(p, skb_gro_offset(p)); + memcpy(skb_mac_header(nskb), skb_mac_header(p), + p->data - skb_mac_header(p)); + + *NAPI_GRO_CB(nskb) = *NAPI_GRO_CB(p); + skb_shinfo(nskb)->frag_list = p; + skb_shinfo(nskb)->gso_size = pinfo->gso_size; + pinfo->gso_size = 0; + skb_header_release(p); + nskb->prev = p; + + nskb->data_len += p->len; + nskb->truesize += p->len; + nskb->len += p->len; + + *head = nskb; + nskb->next = p->next; + p->next = NULL; + + p = nskb; + +merge: + if (offset > headlen) { + unsigned int eat = offset - headlen; + + skbinfo->frags[0].page_offset += eat; + skbinfo->frags[0].size -= eat; + skb->data_len -= eat; + skb->len -= eat; + offset = headlen; + } + + __skb_pull(skb, offset); + + p->prev->next = skb; + p->prev = skb; + skb_header_release(skb); + +done: + NAPI_GRO_CB(p)->count++; + p->data_len += len; + p->truesize += len; + p->len += len; + + NAPI_GRO_CB(skb)->same_flow = 1; + return 0; +} +EXPORT_SYMBOL_GPL(skb_gro_receive); + +void __init skb_init(void) +{ + skbuff_head_cache = kmem_cache_create("skbuff_head_cache", + sizeof(struct sk_buff), + 0, + SLAB_HWCACHE_ALIGN|SLAB_PANIC, + NULL); + skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache", + (2*sizeof(struct sk_buff)) + + sizeof(atomic_t), + 0, + SLAB_HWCACHE_ALIGN|SLAB_PANIC, + NULL); +} + +/** + * skb_to_sgvec - Fill a scatter-gather list from a socket buffer + * @skb: Socket buffer containing the buffers to be mapped + * @sg: The scatter-gather list to map into + * @offset: The offset into the buffer's contents to start mapping + * @len: Length of buffer space to be mapped + * + * Fill the specified scatter-gather list with mappings/pointers into a + * region of the buffer space attached to a socket buffer. + */ +static int +__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len) +{ + int start = skb_headlen(skb); + int i, copy = start - offset; + struct sk_buff *frag_iter; + int elt = 0; + + if (copy > 0) { + if (copy > len) + copy = len; + sg_set_buf(sg, skb->data + offset, copy); + elt++; + if ((len -= copy) == 0) + return elt; + offset += copy; + } + + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + int end; + + WARN_ON(start > offset + len); + + end = start + skb_shinfo(skb)->frags[i].size; + if ((copy = end - offset) > 0) { + skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + + if (copy > len) + copy = len; + sg_set_page(&sg[elt], frag->page, copy, + frag->page_offset+offset-start); + elt++; + if (!(len -= copy)) + return elt; + offset += copy; + } + start = end; + } + + skb_walk_frags(skb, frag_iter) { + int end; + + WARN_ON(start > offset + len); + + end = start + frag_iter->len; + if ((copy = end - offset) > 0) { + if (copy > len) + copy = len; + elt += __skb_to_sgvec(frag_iter, sg+elt, offset - start, + copy); + if ((len -= copy) == 0) + return elt; + offset += copy; + } + start = end; + } + BUG_ON(len); + return elt; +} + +int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len) +{ + int nsg = __skb_to_sgvec(skb, sg, offset, len); + + sg_mark_end(&sg[nsg - 1]); + + return nsg; +} +EXPORT_SYMBOL_GPL(skb_to_sgvec); + +/** + * skb_cow_data - Check that a socket buffer's data buffers are writable + * @skb: The socket buffer to check. + * @tailbits: Amount of trailing space to be added + * @trailer: Returned pointer to the skb where the @tailbits space begins + * + * Make sure that the data buffers attached to a socket buffer are + * writable. If they are not, private copies are made of the data buffers + * and the socket buffer is set to use these instead. + * + * If @tailbits is given, make sure that there is space to write @tailbits + * bytes of data beyond current end of socket buffer. @trailer will be + * set to point to the skb in which this space begins. + * + * The number of scatterlist elements required to completely map the + * COW'd and extended socket buffer will be returned. + */ +int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer) +{ + int copyflag; + int elt; + struct sk_buff *skb1, **skb_p; + + /* If skb is cloned or its head is paged, reallocate + * head pulling out all the pages (pages are considered not writable + * at the moment even if they are anonymous). + */ + if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) && + __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL) + return -ENOMEM; + + /* Easy case. Most of packets will go this way. */ + if (!skb_has_frag_list(skb)) { + /* A little of trouble, not enough of space for trailer. + * This should not happen, when stack is tuned to generate + * good frames. OK, on miss we reallocate and reserve even more + * space, 128 bytes is fair. */ + + if (skb_tailroom(skb) < tailbits && + pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC)) + return -ENOMEM; + + /* Voila! */ + *trailer = skb; + return 1; + } + + /* Misery. We are in troubles, going to mincer fragments... */ + + elt = 1; + skb_p = &skb_shinfo(skb)->frag_list; + copyflag = 0; + + while ((skb1 = *skb_p) != NULL) { + int ntail = 0; + + /* The fragment is partially pulled by someone, + * this can happen on input. Copy it and everything + * after it. */ + + if (skb_shared(skb1)) + copyflag = 1; + + /* If the skb is the last, worry about trailer. */ + + if (skb1->next == NULL && tailbits) { + if (skb_shinfo(skb1)->nr_frags || + skb_has_frag_list(skb1) || + skb_tailroom(skb1) < tailbits) + ntail = tailbits + 128; + } + + if (copyflag || + skb_cloned(skb1) || + ntail || + skb_shinfo(skb1)->nr_frags || + skb_has_frag_list(skb1)) { + struct sk_buff *skb2; + + /* Fuck, we are miserable poor guys... */ + if (ntail == 0) + skb2 = skb_copy(skb1, GFP_ATOMIC); + else + skb2 = skb_copy_expand(skb1, + skb_headroom(skb1), + ntail, + GFP_ATOMIC); + if (unlikely(skb2 == NULL)) + return -ENOMEM; + + if (skb1->sk) + skb_set_owner_w(skb2, skb1->sk); + + /* Looking around. Are we still alive? + * OK, link new skb, drop old one */ + + skb2->next = skb1->next; + *skb_p = skb2; + kfree_skb(skb1); + skb1 = skb2; + } + elt++; + *trailer = skb1; + skb_p = &skb1->next; + } + + return elt; +} +EXPORT_SYMBOL_GPL(skb_cow_data); + +static void sock_rmem_free(struct sk_buff *skb) +{ + struct sock *sk = skb->sk; + + atomic_sub(skb->truesize, &sk->sk_rmem_alloc); +} + +/* + * Note: We dont mem charge error packets (no sk_forward_alloc changes) + */ +int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb) +{ + int len = skb->len; + + if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >= + (unsigned)sk->sk_rcvbuf) + return -ENOMEM; + + skb_orphan(skb); + skb->sk = sk; + skb->destructor = sock_rmem_free; + atomic_add(skb->truesize, &sk->sk_rmem_alloc); + + /* before exiting rcu section, make sure dst is refcounted */ + skb_dst_force(skb); + + skb_queue_tail(&sk->sk_error_queue, skb); + if (!sock_flag(sk, SOCK_DEAD)) + sk->sk_data_ready(sk, len); + return 0; +} +EXPORT_SYMBOL(sock_queue_err_skb); + +void skb_tstamp_tx(struct sk_buff *orig_skb, + struct skb_shared_hwtstamps *hwtstamps) +{ + struct sock *sk = orig_skb->sk; + struct sock_exterr_skb *serr; + struct sk_buff *skb; + int err; + + if (!sk) + return; + + skb = skb_clone(orig_skb, GFP_ATOMIC); + if (!skb) + return; + + if (hwtstamps) { + *skb_hwtstamps(skb) = + *hwtstamps; + } else { + /* + * no hardware time stamps available, + * so keep the shared tx_flags and only + * store software time stamp + */ + skb->tstamp = ktime_get_real(); + } + + serr = SKB_EXT_ERR(skb); + memset(serr, 0, sizeof(*serr)); + serr->ee.ee_errno = ENOMSG; + serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING; + + err = sock_queue_err_skb(sk, skb); + + if (err) + kfree_skb(skb); +} +EXPORT_SYMBOL_GPL(skb_tstamp_tx); + + +/** + * skb_partial_csum_set - set up and verify partial csum values for packet + * @skb: the skb to set + * @start: the number of bytes after skb->data to start checksumming. + * @off: the offset from start to place the checksum. + * + * For untrusted partially-checksummed packets, we need to make sure the values + * for skb->csum_start and skb->csum_offset are valid so we don't oops. + * + * This function checks and sets those values and skb->ip_summed: if this + * returns false you should drop the packet. + */ +bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off) +{ + if (unlikely(start > skb_headlen(skb)) || + unlikely((int)start + off > skb_headlen(skb) - 2)) { + if (net_ratelimit()) + printk(KERN_WARNING + "bad partial csum: csum=%u/%u len=%u\n", + start, off, skb_headlen(skb)); + return false; + } + skb->ip_summed = CHECKSUM_PARTIAL; + skb->csum_start = skb_headroom(skb) + start; + skb->csum_offset = off; + return true; +} +EXPORT_SYMBOL_GPL(skb_partial_csum_set); + +void __skb_warn_lro_forwarding(const struct sk_buff *skb) +{ + if (net_ratelimit()) + pr_warning("%s: received packets cannot be forwarded" + " while LRO is enabled\n", skb->dev->name); +} +EXPORT_SYMBOL(__skb_warn_lro_forwarding); |