| /* |
| * 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 |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #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 <trace/events/skb.h> |
| #include <linux/highmem.h> |
| |
| 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, |
| }; |
| |
| /** |
| * skb_panic - private function for out-of-line support |
| * @skb: buffer |
| * @sz: size |
| * @addr: address |
| * @msg: skb_over_panic or skb_under_panic |
| * |
| * Out-of-line support for skb_put() and skb_push(). |
| * Called via the wrapper skb_over_panic() or skb_under_panic(). |
| * Keep out of line to prevent kernel bloat. |
| * __builtin_return_address is not used because it is not always reliable. |
| */ |
| static void skb_panic(struct sk_buff *skb, unsigned int sz, void *addr, |
| const char msg[]) |
| { |
| pr_emerg("%s: text:%p len:%d put:%d head:%p data:%p tail:%#lx end:%#lx dev:%s\n", |
| msg, addr, skb->len, sz, skb->head, skb->data, |
| (unsigned long)skb->tail, (unsigned long)skb->end, |
| skb->dev ? skb->dev->name : "<NULL>"); |
| BUG(); |
| } |
| |
| static void skb_over_panic(struct sk_buff *skb, unsigned int sz, void *addr) |
| { |
| skb_panic(skb, sz, addr, __func__); |
| } |
| |
| static void skb_under_panic(struct sk_buff *skb, unsigned int sz, void *addr) |
| { |
| skb_panic(skb, sz, addr, __func__); |
| } |
| |
| /* |
| * kmalloc_reserve is a wrapper around kmalloc_node_track_caller that tells |
| * the caller if emergency pfmemalloc reserves are being used. If it is and |
| * the socket is later found to be SOCK_MEMALLOC then PFMEMALLOC reserves |
| * may be used. Otherwise, the packet data may be discarded until enough |
| * memory is free |
| */ |
| #define kmalloc_reserve(size, gfp, node, pfmemalloc) \ |
| __kmalloc_reserve(size, gfp, node, _RET_IP_, pfmemalloc) |
| |
| static void *__kmalloc_reserve(size_t size, gfp_t flags, int node, |
| unsigned long ip, bool *pfmemalloc) |
| { |
| void *obj; |
| bool ret_pfmemalloc = false; |
| |
| /* |
| * Try a regular allocation, when that fails and we're not entitled |
| * to the reserves, fail. |
| */ |
| obj = kmalloc_node_track_caller(size, |
| flags | __GFP_NOMEMALLOC | __GFP_NOWARN, |
| node); |
| if (obj || !(gfp_pfmemalloc_allowed(flags))) |
| goto out; |
| |
| /* Try again but now we are using pfmemalloc reserves */ |
| ret_pfmemalloc = true; |
| obj = kmalloc_node_track_caller(size, flags, node); |
| |
| out: |
| if (pfmemalloc) |
| *pfmemalloc = ret_pfmemalloc; |
| |
| return obj; |
| } |
| |
| /* 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. |
| * |
| */ |
| |
| struct sk_buff *__alloc_skb_head(gfp_t gfp_mask, int node) |
| { |
| struct sk_buff *skb; |
| |
| /* Get the HEAD */ |
| skb = kmem_cache_alloc_node(skbuff_head_cache, |
| gfp_mask & ~__GFP_DMA, node); |
| if (!skb) |
| goto out; |
| |
| /* |
| * 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->head = NULL; |
| skb->truesize = sizeof(struct sk_buff); |
| atomic_set(&skb->users, 1); |
| |
| #ifdef NET_SKBUFF_DATA_USES_OFFSET |
| skb->mac_header = ~0U; |
| #endif |
| out: |
| return skb; |
| } |
| |
| /** |
| * __alloc_skb - allocate a network buffer |
| * @size: size to allocate |
| * @gfp_mask: allocation mask |
| * @flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache |
| * instead of head cache and allocate a cloned (child) skb. |
| * If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for |
| * allocations in case the data is required for writeback |
| * @node: numa node to allocate memory on |
| * |
| * Allocate a new &sk_buff. The returned buffer has no headroom and a |
| * tail room of at least 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 flags, int node) |
| { |
| struct kmem_cache *cache; |
| struct skb_shared_info *shinfo; |
| struct sk_buff *skb; |
| u8 *data; |
| bool pfmemalloc; |
| |
| cache = (flags & SKB_ALLOC_FCLONE) |
| ? skbuff_fclone_cache : skbuff_head_cache; |
| |
| if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX)) |
| gfp_mask |= __GFP_MEMALLOC; |
| |
| /* Get the HEAD */ |
| skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node); |
| if (!skb) |
| goto out; |
| prefetchw(skb); |
| |
| /* We do our best to align skb_shared_info on a separate cache |
| * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives |
| * aligned memory blocks, unless SLUB/SLAB debug is enabled. |
| * Both skb->head and skb_shared_info are cache line aligned. |
| */ |
| size = SKB_DATA_ALIGN(size); |
| size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); |
| data = kmalloc_reserve(size, gfp_mask, node, &pfmemalloc); |
| if (!data) |
| goto nodata; |
| /* kmalloc(size) might give us more room than requested. |
| * Put skb_shared_info exactly at the end of allocated zone, |
| * to allow max possible filling before reallocation. |
| */ |
| size = SKB_WITH_OVERHEAD(ksize(data)); |
| 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)); |
| /* Account for allocated memory : skb + skb->head */ |
| skb->truesize = SKB_TRUESIZE(size); |
| skb->pfmemalloc = pfmemalloc; |
| 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; |
| skb->transport_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 (flags & SKB_ALLOC_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; |
| child->pfmemalloc = pfmemalloc; |
| } |
| out: |
| return skb; |
| nodata: |
| kmem_cache_free(cache, skb); |
| skb = NULL; |
| goto out; |
| } |
| EXPORT_SYMBOL(__alloc_skb); |
| |
| /** |
| * build_skb - build a network buffer |
| * @data: data buffer provided by caller |
| * @frag_size: size of fragment, or 0 if head was kmalloced |
| * |
| * Allocate a new &sk_buff. Caller provides space holding head and |
| * skb_shared_info. @data must have been allocated by kmalloc() |
| * The return is the new skb buffer. |
| * On a failure the return is %NULL, and @data is not freed. |
| * Notes : |
| * Before IO, driver allocates only data buffer where NIC put incoming frame |
| * Driver should add room at head (NET_SKB_PAD) and |
| * MUST add room at tail (SKB_DATA_ALIGN(skb_shared_info)) |
| * After IO, driver calls build_skb(), to allocate sk_buff and populate it |
| * before giving packet to stack. |
| * RX rings only contains data buffers, not full skbs. |
| */ |
| struct sk_buff *build_skb(void *data, unsigned int frag_size) |
| { |
| struct skb_shared_info *shinfo; |
| struct sk_buff *skb; |
| unsigned int size = frag_size ? : ksize(data); |
| |
| skb = kmem_cache_alloc(skbuff_head_cache, GFP_ATOMIC); |
| if (!skb) |
| return NULL; |
| |
| size -= SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); |
| |
| memset(skb, 0, offsetof(struct sk_buff, tail)); |
| skb->truesize = SKB_TRUESIZE(size); |
| skb->head_frag = frag_size != 0; |
| 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; |
| skb->transport_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); |
| |
| return skb; |
| } |
| EXPORT_SYMBOL(build_skb); |
| |
| struct netdev_alloc_cache { |
| struct page_frag frag; |
| /* we maintain a pagecount bias, so that we dont dirty cache line |
| * containing page->_count every time we allocate a fragment. |
| */ |
| unsigned int pagecnt_bias; |
| }; |
| static DEFINE_PER_CPU(struct netdev_alloc_cache, netdev_alloc_cache); |
| |
| static void *__netdev_alloc_frag(unsigned int fragsz, gfp_t gfp_mask) |
| { |
| struct netdev_alloc_cache *nc; |
| void *data = NULL; |
| int order; |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| nc = &__get_cpu_var(netdev_alloc_cache); |
| if (unlikely(!nc->frag.page)) { |
| refill: |
| for (order = NETDEV_FRAG_PAGE_MAX_ORDER; ;) { |
| gfp_t gfp = gfp_mask; |
| |
| if (order) |
| gfp |= __GFP_COMP | __GFP_NOWARN; |
| nc->frag.page = alloc_pages(gfp, order); |
| if (likely(nc->frag.page)) |
| break; |
| if (--order < 0) |
| goto end; |
| } |
| nc->frag.size = PAGE_SIZE << order; |
| recycle: |
| atomic_set(&nc->frag.page->_count, NETDEV_PAGECNT_MAX_BIAS); |
| nc->pagecnt_bias = NETDEV_PAGECNT_MAX_BIAS; |
| nc->frag.offset = 0; |
| } |
| |
| if (nc->frag.offset + fragsz > nc->frag.size) { |
| /* avoid unnecessary locked operations if possible */ |
| if ((atomic_read(&nc->frag.page->_count) == nc->pagecnt_bias) || |
| atomic_sub_and_test(nc->pagecnt_bias, &nc->frag.page->_count)) |
| goto recycle; |
| goto refill; |
| } |
| |
| data = page_address(nc->frag.page) + nc->frag.offset; |
| nc->frag.offset += fragsz; |
| nc->pagecnt_bias--; |
| end: |
| local_irq_restore(flags); |
| return data; |
| } |
| |
| /** |
| * netdev_alloc_frag - allocate a page fragment |
| * @fragsz: fragment size |
| * |
| * Allocates a frag from a page for receive buffer. |
| * Uses GFP_ATOMIC allocations. |
| */ |
| void *netdev_alloc_frag(unsigned int fragsz) |
| { |
| return __netdev_alloc_frag(fragsz, GFP_ATOMIC | __GFP_COLD); |
| } |
| EXPORT_SYMBOL(netdev_alloc_frag); |
| |
| /** |
| * __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 = NULL; |
| unsigned int fragsz = SKB_DATA_ALIGN(length + NET_SKB_PAD) + |
| SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); |
| |
| if (fragsz <= PAGE_SIZE && !(gfp_mask & (__GFP_WAIT | GFP_DMA))) { |
| void *data; |
| |
| if (sk_memalloc_socks()) |
| gfp_mask |= __GFP_MEMALLOC; |
| |
| data = __netdev_alloc_frag(fragsz, gfp_mask); |
| |
| if (likely(data)) { |
| skb = build_skb(data, fragsz); |
| if (unlikely(!skb)) |
| put_page(virt_to_head_page(data)); |
| } |
| } else { |
| skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, |
| SKB_ALLOC_RX, 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, unsigned int truesize) |
| { |
| skb_fill_page_desc(skb, i, page, off, size); |
| skb->len += size; |
| skb->data_len += size; |
| skb->truesize += truesize; |
| } |
| EXPORT_SYMBOL(skb_add_rx_frag); |
| |
| static void skb_drop_list(struct sk_buff **listp) |
| { |
| kfree_skb_list(*listp); |
| *listp = NULL; |
| } |
| |
| static inline void skb_drop_fraglist(struct sk_buff *skb) |
| { |
| skb_drop_list(&skb_shinfo(skb)->frag_list); |
| } |
| |
| void skb_clone_fraglist(struct sk_buff *skb) |
| { |
| struct sk_buff *list; |
| |
| skb_walk_frags(skb, list) |
| skb_get(list); |
| } |
| EXPORT_SYMBOL(skb_clone_fraglist); |
| |
| static void skb_free_head(struct sk_buff *skb) |
| { |
| if (skb->head_frag) |
| put_page(virt_to_head_page(skb->head)); |
| else |
| kfree(skb->head); |
| } |
| |
| 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++) |
| skb_frag_unref(skb, i); |
| } |
| |
| /* |
| * If skb buf is from userspace, we need to notify the caller |
| * the lower device DMA has done; |
| */ |
| if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) { |
| struct ubuf_info *uarg; |
| |
| uarg = skb_shinfo(skb)->destructor_arg; |
| if (uarg->callback) |
| uarg->callback(uarg, true); |
| } |
| |
| if (skb_has_frag_list(skb)) |
| skb_drop_fraglist(skb); |
| |
| skb_free_head(skb); |
| } |
| } |
| |
| /* |
| * 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 IS_ENABLED(CONFIG_NF_CONNTRACK) |
| 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); |
| if (likely(skb->head)) |
| 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); |
| |
| void kfree_skb_list(struct sk_buff *segs) |
| { |
| while (segs) { |
| struct sk_buff *next = segs->next; |
| |
| kfree_skb(segs); |
| segs = next; |
| } |
| } |
| EXPORT_SYMBOL(kfree_skb_list); |
| |
| /** |
| * skb_tx_error - report an sk_buff xmit error |
| * @skb: buffer that triggered an error |
| * |
| * Report xmit error if a device callback is tracking this skb. |
| * skb must be freed afterwards. |
| */ |
| void skb_tx_error(struct sk_buff *skb) |
| { |
| if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) { |
| struct ubuf_info *uarg; |
| |
| uarg = skb_shinfo(skb)->destructor_arg; |
| if (uarg->callback) |
| uarg->callback(uarg, false); |
| skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY; |
| } |
| } |
| EXPORT_SYMBOL(skb_tx_error); |
| |
| /** |
| * 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); |
| |
| 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; |
| new->inner_transport_header = old->inner_transport_header; |
| new->inner_network_header = old->inner_network_header; |
| new->inner_mac_header = old->inner_mac_header; |
| skb_dst_copy(new, old); |
| new->rxhash = old->rxhash; |
| new->ooo_okay = old->ooo_okay; |
| new->l4_rxhash = old->l4_rxhash; |
| new->no_fcs = old->no_fcs; |
| new->encapsulation = old->encapsulation; |
| #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 IS_ENABLED(CONFIG_IP_VS) |
| new->ipvs_property = old->ipvs_property; |
| #endif |
| new->pfmemalloc = old->pfmemalloc; |
| new->protocol = old->protocol; |
| new->mark = old->mark; |
| new->skb_iif = old->skb_iif; |
| __nf_copy(new, old); |
| #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) |
| 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_proto = old->vlan_proto; |
| 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(head_frag); |
| 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_copy_ubufs - copy userspace skb frags buffers to kernel |
| * @skb: the skb to modify |
| * @gfp_mask: allocation priority |
| * |
| * This must be called on SKBTX_DEV_ZEROCOPY skb. |
| * It will copy all frags into kernel and drop the reference |
| * to userspace pages. |
| * |
| * If this function is called from an interrupt gfp_mask() must be |
| * %GFP_ATOMIC. |
| * |
| * Returns 0 on success or a negative error code on failure |
| * to allocate kernel memory to copy to. |
| */ |
| int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask) |
| { |
| int i; |
| int num_frags = skb_shinfo(skb)->nr_frags; |
| struct page *page, *head = NULL; |
| struct ubuf_info *uarg = skb_shinfo(skb)->destructor_arg; |
| |
| for (i = 0; i < num_frags; i++) { |
| u8 *vaddr; |
| skb_frag_t *f = &skb_shinfo(skb)->frags[i]; |
| |
| page = alloc_page(gfp_mask); |
| if (!page) { |
| while (head) { |
| struct page *next = (struct page *)head->private; |
| put_page(head); |
| head = next; |
| } |
| return -ENOMEM; |
| } |
| vaddr = kmap_atomic(skb_frag_page(f)); |
| memcpy(page_address(page), |
| vaddr + f->page_offset, skb_frag_size(f)); |
| kunmap_atomic(vaddr); |
| page->private = (unsigned long)head; |
| head = page; |
| } |
| |
| /* skb frags release userspace buffers */ |
| for (i = 0; i < num_frags; i++) |
| skb_frag_unref(skb, i); |
| |
| uarg->callback(uarg, false); |
| |
| /* skb frags point to kernel buffers */ |
| for (i = num_frags - 1; i >= 0; i--) { |
| __skb_fill_page_desc(skb, i, head, 0, |
| skb_shinfo(skb)->frags[i].size); |
| head = (struct page *)head->private; |
| } |
| |
| skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY; |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(skb_copy_ubufs); |
| |
| /** |
| * 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; |
| |
| if (skb_orphan_frags(skb, gfp_mask)) |
| return NULL; |
| |
| 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 { |
| if (skb_pfmemalloc(skb)) |
| gfp_mask |= __GFP_MEMALLOC; |
| |
| 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 skb_headers_offset_update(struct sk_buff *skb, int off) |
| { |
| /* {transport,network,mac}_header and tail are relative to skb->head */ |
| skb->transport_header += off; |
| skb->network_header += off; |
| if (skb_mac_header_was_set(skb)) |
| skb->mac_header += off; |
| skb->inner_transport_header += off; |
| skb->inner_network_header += off; |
| skb->inner_mac_header += off; |
| } |
| |
| 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 |
| skb_headers_offset_update(new, 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; |
| } |
| EXPORT_SYMBOL(copy_skb_header); |
| |
| static inline int skb_alloc_rx_flag(const struct sk_buff *skb) |
| { |
| if (skb_pfmemalloc(skb)) |
| return SKB_ALLOC_RX; |
| return 0; |
| } |
| |
| /** |
| * 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_offset(skb) + skb->data_len; |
| struct sk_buff *n = __alloc_skb(size, gfp_mask, |
| skb_alloc_rx_flag(skb), NUMA_NO_NODE); |
| |
| 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 |
| * @headroom: headroom of new skb |
| * @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 headroom, gfp_t gfp_mask) |
| { |
| unsigned int size = skb_headlen(skb) + headroom; |
| struct sk_buff *n = __alloc_skb(size, gfp_mask, |
| skb_alloc_rx_flag(skb), NUMA_NO_NODE); |
| |
| if (!n) |
| goto out; |
| |
| /* Set the data pointer */ |
| skb_reserve(n, headroom); |
| /* 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; |
| |
| if (skb_orphan_frags(skb, gfp_mask)) { |
| kfree_skb(n); |
| n = NULL; |
| goto out; |
| } |
| for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
| skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i]; |
| skb_frag_ref(skb, i); |
| } |
| 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_offset(skb) + ntail; |
| long off; |
| |
| BUG_ON(nhead < 0); |
| |
| if (skb_shared(skb)) |
| BUG(); |
| |
| size = SKB_DATA_ALIGN(size); |
| |
| if (skb_pfmemalloc(skb)) |
| gfp_mask |= __GFP_MEMALLOC; |
| data = kmalloc_reserve(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)), |
| gfp_mask, NUMA_NO_NODE, NULL); |
| if (!data) |
| goto nodata; |
| size = SKB_WITH_OVERHEAD(ksize(data)); |
| |
| /* 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 shinfo is shared we must drop the old head gracefully, but if it |
| * is not we can just drop the old head and let the existing refcount |
| * be since all we did is relocate the values |
| */ |
| if (skb_cloned(skb)) { |
| /* copy this zero copy skb frags */ |
| if (skb_orphan_frags(skb, gfp_mask)) |
| goto nofrags; |
| for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) |
| skb_frag_ref(skb, i); |
| |
| if (skb_has_frag_list(skb)) |
| skb_clone_fraglist(skb); |
| |
| skb_release_data(skb); |
| } else { |
| skb_free_head(skb); |
| } |
| off = (data + nhead) - skb->head; |
| |
| skb->head = data; |
| skb->head_frag = 0; |
| skb->data += off; |
| #ifdef NET_SKBUFF_DATA_USES_OFFSET |
| skb->end = size; |
| off = nhead; |
| #else |
| skb->end = skb->head + size; |
| #endif |
| skb->tail += off; |
| skb_headers_offset_update(skb, 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; |
| |
| nofrags: |
| kfree(data); |
| 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, skb_alloc_rx_flag(skb), |
| NUMA_NO_NODE); |
| 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 |
| skb_headers_offset_update(n, 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_frag_size(&skb_shinfo(skb)->frags[i]); |
| |
| if (end < len) { |
| offset = end; |
| continue; |
| } |
| |
| skb_frag_size_set(&skb_shinfo(skb)->frags[i++], len - offset); |
| |
| drop_pages: |
| skb_shinfo(skb)->nr_frags = i; |
| |
| for (; i < nfrags; i++) |
| skb_frag_unref(skb, i); |
| |
| 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; |
| consume_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++) { |
| int size = skb_frag_size(&skb_shinfo(skb)->frags[i]); |
| |
| if (size >= eat) |
| goto pull_pages; |
| eat -= 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++) { |
| int size = skb_frag_size(&skb_shinfo(skb)->frags[i]); |
| |
| if (size <= eat) { |
| skb_frag_unref(skb, i); |
| eat -= size; |
| } else { |
| skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i]; |
| if (eat) { |
| skb_shinfo(skb)->frags[k].page_offset += eat; |
| skb_frag_size_sub(&skb_shinfo(skb)->frags[k], 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); |
| |
| /** |
| * skb_copy_bits - copy bits from skb to kernel buffer |
| * @skb: source skb |
| * @offset: offset in source |
| * @to: destination buffer |
| * @len: number of bytes to copy |
| * |
| * Copy the specified number of bytes from the source skb to the |
| * destination buffer. |
| * |
| * CAUTION ! : |
| * If its prototype is ever changed, |
| * check arch/{*}/net/{*}.S files, |
| * since it is called from BPF assembly code. |
| */ |
| 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; |
| skb_frag_t *f = &skb_shinfo(skb)->frags[i]; |
| |
| WARN_ON(start > offset + len); |
| |
| end = start + skb_frag_size(f); |
| if ((copy = end - offset) > 0) { |
| u8 *vaddr; |
| |
| if (copy > len) |
| copy = len; |
| |
| vaddr = kmap_atomic(skb_frag_page(f)); |
| memcpy(to, |
| vaddr + f->page_offset + offset - start, |
| copy); |
| kunmap_atomic(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 struct page *linear_to_page(struct page *page, unsigned int *len, |
| unsigned int *offset, |
| struct sock *sk) |
| { |
| struct page_frag *pfrag = sk_page_frag(sk); |
| |
| if (!sk_page_frag_refill(sk, pfrag)) |
| return NULL; |
| |
| *len = min_t(unsigned int, *len, pfrag->size - pfrag->offset); |
| |
| memcpy(page_address(pfrag->page) + pfrag->offset, |
| page_address(page) + *offset, *len); |
| *offset = pfrag->offset; |
| pfrag->offset += *len; |
| |
| return pfrag->page; |
| } |
| |
| static bool spd_can_coalesce(const struct splice_pipe_desc *spd, |
| struct page *page, |
| unsigned int offset) |
| { |
| return spd->nr_pages && |
| spd->pages[spd->nr_pages - 1] == page && |
| (spd->partial[spd->nr_pages - 1].offset + |
| spd->partial[spd->nr_pages - 1].len == offset); |
| } |
| |
| /* |
| * Fill page/offset/length into spd, if it can hold more pages. |
| */ |
| static bool spd_fill_page(struct splice_pipe_desc *spd, |
| struct pipe_inode_info *pipe, struct page *page, |
| unsigned int *len, unsigned int offset, |
| bool linear, |
| struct sock *sk) |
| { |
| if (unlikely(spd->nr_pages == MAX_SKB_FRAGS)) |
| return true; |
| |
| if (linear) { |
| page = linear_to_page(page, len, &offset, sk); |
| if (!page) |
| return true; |
| } |
| if (spd_can_coalesce(spd, page, offset)) { |
| spd->partial[spd->nr_pages - 1].len += *len; |
| return false; |
| } |
| 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 false; |
| } |
| |
| static bool __splice_segment(struct page *page, unsigned int poff, |
| unsigned int plen, unsigned int *off, |
| unsigned int *len, |
| struct splice_pipe_desc *spd, bool linear, |
| struct sock *sk, |
| struct pipe_inode_info *pipe) |
| { |
| if (!*len) |
| return true; |
| |
| /* skip this segment if already processed */ |
| if (*off >= plen) { |
| *off -= plen; |
| return false; |
| } |
| |
| /* ignore any bits we already processed */ |
| poff += *off; |
| plen -= *off; |
| *off = 0; |
| |
| do { |
| unsigned int flen = min(*len, plen); |
| |
| if (spd_fill_page(spd, pipe, page, &flen, poff, |
| linear, sk)) |
| return true; |
| poff += flen; |
| plen -= flen; |
| *len -= flen; |
| } while (*len && plen); |
| |
| return false; |
| } |
| |
| /* |
| * Map linear and fragment data from the skb to spd. It reports true if the |
| * pipe is full or if we already spliced the requested length. |
| */ |
| static bool __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 skb->head_frag is set, this 'linear' part is backed by a |
| * fragment, and if the head is not shared with any clones then |
| * we can avoid a copy since we own the head portion of this page. |
| */ |
| if (__splice_segment(virt_to_page(skb->data), |
| (unsigned long) skb->data & (PAGE_SIZE - 1), |
| skb_headlen(skb), |
| offset, len, spd, |
| skb_head_is_locked(skb), |
| sk, pipe)) |
| return true; |
| |
| /* |
| * 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(skb_frag_page(f), |
| f->page_offset, skb_frag_size(f), |
| offset, len, spd, false, sk, pipe)) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /* |
| * 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[MAX_SKB_FRAGS]; |
| struct page *pages[MAX_SKB_FRAGS]; |
| struct splice_pipe_desc spd = { |
| .pages = pages, |
| .partial = partial, |
| .nr_pages_max = MAX_SKB_FRAGS, |
| .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; |
| |
| /* |
| * __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); |
| } |
| |
| 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 + skb_frag_size(frag); |
| if ((copy = end - offset) > 0) { |
| u8 *vaddr; |
| |
| if (copy > len) |
| copy = len; |
| |
| vaddr = kmap_atomic(skb_frag_page(frag)); |
| memcpy(vaddr + frag->page_offset + offset - start, |
| from, copy); |
| kunmap_atomic(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; |
| skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; |
| |
| WARN_ON(start > offset + len); |
| |
| end = start + skb_frag_size(frag); |
| if ((copy = end - offset) > 0) { |
| __wsum csum2; |
| u8 *vaddr; |
| |
| if (copy > len) |
| copy = len; |
| vaddr = kmap_atomic(skb_frag_page(frag)); |
| csum2 = csum_partial(vaddr + frag->page_offset + |
| offset - start, copy, 0); |
| kunmap_atomic(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_frag_size(&skb_shinfo(skb)->frags[i]); |
| 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_atomic(skb_frag_page(frag)); |
| csum2 = csum_partial_copy_nocheck(vaddr + |
| frag->page_offset + |
| offset - start, to, |
| copy, 0); |
| kunmap_atomic(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_frag_size(&skb_shinfo(skb)->frags[i]); |
| |
| 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. |
| */ |
| skb_frag_ref(skb, i); |
| skb_shinfo(skb1)->frags[0].page_offset += len - pos; |
| skb_frag_size_sub(&skb_shinfo(skb1)->frags[0], len - pos); |
| skb_frag_size_set(&skb_shinfo(skb)->frags[i], 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); |
| |
| skb_shinfo(skb1)->tx_flags = skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG; |
| 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 skb to tgt. 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, skb_frag_page(fragfrom), |
| fragfrom->page_offset)) { |
| merge = -1; |
| } else { |
| merge = to - 1; |
| |
| todo -= skb_frag_size(fragfrom); |
| 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]; |
| |
| skb_frag_size_add(fragto, shiftlen); |
| skb_frag_size_sub(fragfrom, 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 >= skb_frag_size(fragfrom)) { |
| *fragto = *fragfrom; |
| todo -= skb_frag_size(fragfrom); |
| from++; |
| to++; |
| |
| } else { |
| __skb_frag_ref(fragfrom); |
| fragto->page = fragfrom->page; |
| fragto->page_offset = fragfrom->page_offset; |
| skb_frag_size_set(fragto, todo); |
| |
| fragfrom->page_offset += todo; |
| skb_frag_size_sub(fragfrom, 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]; |
| |
| skb_frag_size_add(fragto, skb_frag_size(fragfrom)); |
| __skb_frag_unref(fragfrom); |
| } |
| |
| /* 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 = skb_frag_size(frag) + st->stepped_offset; |
| |
| if (abs_offset < block_limit) { |
| if (!st->frag_data) |
| st->frag_data = kmap_atomic(skb_frag_page(frag)); |
| |
| *data = (u8 *) st->frag_data + frag->page_offset + |
| (abs_offset - st->stepped_offset); |
| |
| return block_limit - abs_offset; |
| } |
| |
| if (st->frag_data) { |
| kunmap_atomic(st->frag_data); |
| st->frag_data = NULL; |
| } |
| |
| st->frag_idx++; |
| st->stepped_offset += skb_frag_size(frag); |
| } |
| |
| if (st->frag_data) { |
| kunmap_atomic(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_atomic(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 = skb_shinfo(skb)->nr_frags; |
| int copy; |
| int offset = 0; |
| int ret; |
| struct page_frag *pfrag = ¤t->task_frag; |
| |
| do { |
| /* Return error if we don't have space for new frag */ |
| if (frg_cnt >= MAX_SKB_FRAGS) |
| return -EMSGSIZE; |
| |
| if (!sk_page_frag_refill(sk, pfrag)) |
| return -ENOMEM; |
| |
| /* copy the user data to page */ |
| copy = min_t(int, length, pfrag->size - pfrag->offset); |
| |
| ret = getfrag(from, page_address(pfrag->page) + pfrag->offset, |
| offset, copy, 0, skb); |
| if (ret < 0) |
| return -EFAULT; |
| |
| /* copy was successful so update the size parameters */ |
| skb_fill_page_desc(skb, frg_cnt, pfrag->page, pfrag->offset, |
| copy); |
| frg_cnt++; |
| pfrag->offset += copy; |
| get_page(pfrag->page); |
| |
| skb->truesize += copy; |
| atomic_add(copy, &sk->sk_wmem_alloc); |
| 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, netdev_features_t 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 tnl_hlen = skb_tnl_header_len(skb); |
| unsigned int headroom; |
| unsigned int len; |
| __be16 proto; |
| bool csum; |
| int sg = !!(features & NETIF_F_SG); |
| int nfrags = skb_shinfo(skb)->nr_frags; |
| int err = -ENOMEM; |
| int i = 0; |
| int pos; |
| |
| proto = skb_network_protocol(skb); |
| if (unlikely(!proto)) |
| return ERR_PTR(-EINVAL); |
| |
| csum = !!can_checksum_protocol(features, proto); |
| __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_offset(nskb); |
| if (skb_cow_head(nskb, doffset + headroom)) { |
| kfree_skb(nskb); |
| goto err; |
| } |
| |
| nskb->truesize += skb_end_offset(nskb) - hsize; |
| skb_release_head_state(nskb); |
| __skb_push(nskb, doffset); |
| } else { |
| nskb = __alloc_skb(hsize + doffset + headroom, |
| GFP_ATOMIC, skb_alloc_rx_flag(skb), |
| NUMA_NO_NODE); |
| |
| 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_offset(skb, -tnl_hlen, |
| nskb->data - tnl_hlen, |
| doffset + tnl_hlen); |
| |
| 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); |
| |
| skb_shinfo(nskb)->tx_flags = skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG; |
| |
| while (pos < offset + len && i < nfrags) { |
| *frag = skb_shinfo(skb)->frags[i]; |
| __skb_frag_ref(frag); |
| size = skb_frag_size(frag); |
| |
| if (pos < offset) { |
| frag->page_offset += offset - pos; |
| skb_frag_size_sub(frag, offset - pos); |
| } |
| |
| skb_shinfo(nskb)->nr_frags++; |
| |
| if (pos + size <= offset + len) { |
| i++; |
| pos += size; |
| } else { |
| skb_frag_size_sub(frag, 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; |
| |
| if (!csum) { |
| nskb->csum = skb_checksum(nskb, doffset, |
| nskb->len - doffset, 0); |
| nskb->ip_summed = CHECKSUM_NONE; |
| } |
| } 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); |
| unsigned int delta_truesize; |
| |
| 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; |
| skb_frag_size_sub(frag, offset); |
| |
| /* all fragments truesize : remove (head size + sk_buff) */ |
| delta_truesize = skb->truesize - |
| SKB_TRUESIZE(skb_end_offset(skb)); |
| |
| skb->truesize -= skb->data_len; |
| skb->len -= skb->data_len; |
| skb->data_len = 0; |
| |
| NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE; |
| goto done; |
| } else if (skb->head_frag) { |
| int nr_frags = pinfo->nr_frags; |
| skb_frag_t *frag = pinfo->frags + nr_frags; |
| struct page *page = virt_to_head_page(skb->head); |
| unsigned int first_size = headlen - offset; |
| unsigned int first_offset; |
| |
| if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS) |
| return -E2BIG; |
| |
| first_offset = skb->data - |
| (unsigned char *)page_address(page) + |
| offset; |
| |
| pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags; |
| |
| frag->page.p = page; |
| frag->page_offset = first_offset; |
| skb_frag_size_set(frag, first_size); |
| |
| memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags); |
| /* We dont need to clear skbinfo->nr_frags here */ |
| |
| delta_truesize = skb->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff)); |
| NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD; |
| 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)); |
| |
| skb_shinfo(nskb)->frag_list = p; |
| skb_shinfo(nskb)->gso_size = pinfo->gso_size; |
| pinfo->gso_size = 0; |
| skb_header_release(p); |
| NAPI_GRO_CB(nskb)->last = p; |
| |
| nskb->data_len += p->len; |
| nskb->truesize += p->truesize; |
| nskb->len += p->len; |
| |
| *head = nskb; |
| nskb->next = p->next; |
| p->next = NULL; |
| |
| p = nskb; |
| |
| merge: |
| delta_truesize = skb->truesize; |
| if (offset > headlen) { |
| unsigned int eat = offset - headlen; |
| |
| skbinfo->frags[0].page_offset += eat; |
| skb_frag_size_sub(&skbinfo->frags[0], eat); |
| skb->data_len -= eat; |
| skb->len -= eat; |
| offset = headlen; |
| } |
| |
| __skb_pull(skb, offset); |
| |
| NAPI_GRO_CB(p)->last->next = skb; |
| NAPI_GRO_CB(p)->last = skb; |
| skb_header_release(skb); |
| |
| done: |
| NAPI_GRO_CB(p)->count++; |
| p->data_len += len; |
| p->truesize += delta_truesize; |
| 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_frag_size(&skb_shinfo(skb)->frags[i]); |
| if ((copy = end - offset) > 0) { |
| skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; |
| |
| if (copy > len) |
| copy = len; |
| sg_set_page(&sg[elt], skb_frag_page(frag), 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); |
| |