diff options
Diffstat (limited to 'net/core/skbuff.c')
| -rw-r--r-- | net/core/skbuff.c | 6937 |
1 files changed, 6937 insertions, 0 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c new file mode 100644 index 000000000..011d69029 --- /dev/null +++ b/net/core/skbuff.c @@ -0,0 +1,6937 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * 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). + */ + +/* + * 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/mm.h> +#include <linux/interrupt.h> +#include <linux/in.h> +#include <linux/inet.h> +#include <linux/slab.h> +#include <linux/tcp.h> +#include <linux/udp.h> +#include <linux/sctp.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 <linux/bitfield.h> +#include <linux/if_vlan.h> +#include <linux/mpls.h> +#include <linux/kcov.h> + +#include <net/protocol.h> +#include <net/dst.h> +#include <net/sock.h> +#include <net/checksum.h> +#include <net/gso.h> +#include <net/ip6_checksum.h> +#include <net/xfrm.h> +#include <net/mpls.h> +#include <net/mptcp.h> +#include <net/mctp.h> +#include <net/page_pool/helpers.h> +#include <net/dropreason.h> + +#include <linux/uaccess.h> +#include <trace/events/skb.h> +#include <linux/highmem.h> +#include <linux/capability.h> +#include <linux/user_namespace.h> +#include <linux/indirect_call_wrapper.h> +#include <linux/textsearch.h> + +#include "dev.h" +#include "sock_destructor.h" + +struct kmem_cache *skbuff_cache __ro_after_init; +static struct kmem_cache *skbuff_fclone_cache __ro_after_init; +#ifdef CONFIG_SKB_EXTENSIONS +static struct kmem_cache *skbuff_ext_cache __ro_after_init; +#endif + + +static struct kmem_cache *skb_small_head_cache __ro_after_init; + +#define SKB_SMALL_HEAD_SIZE SKB_HEAD_ALIGN(MAX_TCP_HEADER) + +/* We want SKB_SMALL_HEAD_CACHE_SIZE to not be a power of two. + * This should ensure that SKB_SMALL_HEAD_HEADROOM is a unique + * size, and we can differentiate heads from skb_small_head_cache + * vs system slabs by looking at their size (skb_end_offset()). + */ +#define SKB_SMALL_HEAD_CACHE_SIZE \ + (is_power_of_2(SKB_SMALL_HEAD_SIZE) ? \ + (SKB_SMALL_HEAD_SIZE + L1_CACHE_BYTES) : \ + SKB_SMALL_HEAD_SIZE) + +#define SKB_SMALL_HEAD_HEADROOM \ + SKB_WITH_OVERHEAD(SKB_SMALL_HEAD_CACHE_SIZE) + +int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS; +EXPORT_SYMBOL(sysctl_max_skb_frags); + +#undef FN +#define FN(reason) [SKB_DROP_REASON_##reason] = #reason, +static const char * const drop_reasons[] = { + [SKB_CONSUMED] = "CONSUMED", + DEFINE_DROP_REASON(FN, FN) +}; + +static const struct drop_reason_list drop_reasons_core = { + .reasons = drop_reasons, + .n_reasons = ARRAY_SIZE(drop_reasons), +}; + +const struct drop_reason_list __rcu * +drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_NUM] = { + [SKB_DROP_REASON_SUBSYS_CORE] = RCU_INITIALIZER(&drop_reasons_core), +}; +EXPORT_SYMBOL(drop_reasons_by_subsys); + +/** + * drop_reasons_register_subsys - register another drop reason subsystem + * @subsys: the subsystem to register, must not be the core + * @list: the list of drop reasons within the subsystem, must point to + * a statically initialized list + */ +void drop_reasons_register_subsys(enum skb_drop_reason_subsys subsys, + const struct drop_reason_list *list) +{ + if (WARN(subsys <= SKB_DROP_REASON_SUBSYS_CORE || + subsys >= ARRAY_SIZE(drop_reasons_by_subsys), + "invalid subsystem %d\n", subsys)) + return; + + /* must point to statically allocated memory, so INIT is OK */ + RCU_INIT_POINTER(drop_reasons_by_subsys[subsys], list); +} +EXPORT_SYMBOL_GPL(drop_reasons_register_subsys); + +/** + * drop_reasons_unregister_subsys - unregister a drop reason subsystem + * @subsys: the subsystem to remove, must not be the core + * + * Note: This will synchronize_rcu() to ensure no users when it returns. + */ +void drop_reasons_unregister_subsys(enum skb_drop_reason_subsys subsys) +{ + if (WARN(subsys <= SKB_DROP_REASON_SUBSYS_CORE || + subsys >= ARRAY_SIZE(drop_reasons_by_subsys), + "invalid subsystem %d\n", subsys)) + return; + + RCU_INIT_POINTER(drop_reasons_by_subsys[subsys], NULL); + + synchronize_rcu(); +} +EXPORT_SYMBOL_GPL(drop_reasons_unregister_subsys); + +/** + * 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:%px len:%d put:%d head:%px data:%px 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__); +} + +#define NAPI_SKB_CACHE_SIZE 64 +#define NAPI_SKB_CACHE_BULK 16 +#define NAPI_SKB_CACHE_HALF (NAPI_SKB_CACHE_SIZE / 2) + +#if PAGE_SIZE == SZ_4K + +#define NAPI_HAS_SMALL_PAGE_FRAG 1 +#define NAPI_SMALL_PAGE_PFMEMALLOC(nc) ((nc).pfmemalloc) + +/* specialized page frag allocator using a single order 0 page + * and slicing it into 1K sized fragment. Constrained to systems + * with a very limited amount of 1K fragments fitting a single + * page - to avoid excessive truesize underestimation + */ + +struct page_frag_1k { + void *va; + u16 offset; + bool pfmemalloc; +}; + +static void *page_frag_alloc_1k(struct page_frag_1k *nc, gfp_t gfp) +{ + struct page *page; + int offset; + + offset = nc->offset - SZ_1K; + if (likely(offset >= 0)) + goto use_frag; + + page = alloc_pages_node(NUMA_NO_NODE, gfp, 0); + if (!page) + return NULL; + + nc->va = page_address(page); + nc->pfmemalloc = page_is_pfmemalloc(page); + offset = PAGE_SIZE - SZ_1K; + page_ref_add(page, offset / SZ_1K); + +use_frag: + nc->offset = offset; + return nc->va + offset; +} +#else + +/* the small page is actually unused in this build; add dummy helpers + * to please the compiler and avoid later preprocessor's conditionals + */ +#define NAPI_HAS_SMALL_PAGE_FRAG 0 +#define NAPI_SMALL_PAGE_PFMEMALLOC(nc) false + +struct page_frag_1k { +}; + +static void *page_frag_alloc_1k(struct page_frag_1k *nc, gfp_t gfp_mask) +{ + return NULL; +} + +#endif + +struct napi_alloc_cache { + struct page_frag_cache page; + struct page_frag_1k page_small; + unsigned int skb_count; + void *skb_cache[NAPI_SKB_CACHE_SIZE]; +}; + +static DEFINE_PER_CPU(struct page_frag_cache, netdev_alloc_cache); +static DEFINE_PER_CPU(struct napi_alloc_cache, napi_alloc_cache); + +/* Double check that napi_get_frags() allocates skbs with + * skb->head being backed by slab, not a page fragment. + * This is to make sure bug fixed in 3226b158e67c + * ("net: avoid 32 x truesize under-estimation for tiny skbs") + * does not accidentally come back. + */ +void napi_get_frags_check(struct napi_struct *napi) +{ + struct sk_buff *skb; + + local_bh_disable(); + skb = napi_get_frags(napi); + WARN_ON_ONCE(!NAPI_HAS_SMALL_PAGE_FRAG && skb && skb->head_frag); + napi_free_frags(napi); + local_bh_enable(); +} + +void *__napi_alloc_frag_align(unsigned int fragsz, unsigned int align_mask) +{ + struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache); + + fragsz = SKB_DATA_ALIGN(fragsz); + + return page_frag_alloc_align(&nc->page, fragsz, GFP_ATOMIC, align_mask); +} +EXPORT_SYMBOL(__napi_alloc_frag_align); + +void *__netdev_alloc_frag_align(unsigned int fragsz, unsigned int align_mask) +{ + void *data; + + fragsz = SKB_DATA_ALIGN(fragsz); + if (in_hardirq() || irqs_disabled()) { + struct page_frag_cache *nc = this_cpu_ptr(&netdev_alloc_cache); + + data = page_frag_alloc_align(nc, fragsz, GFP_ATOMIC, align_mask); + } else { + struct napi_alloc_cache *nc; + + local_bh_disable(); + nc = this_cpu_ptr(&napi_alloc_cache); + data = page_frag_alloc_align(&nc->page, fragsz, GFP_ATOMIC, align_mask); + local_bh_enable(); + } + return data; +} +EXPORT_SYMBOL(__netdev_alloc_frag_align); + +static struct sk_buff *napi_skb_cache_get(void) +{ + struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache); + struct sk_buff *skb; + + if (unlikely(!nc->skb_count)) { + nc->skb_count = kmem_cache_alloc_bulk(skbuff_cache, + GFP_ATOMIC, + NAPI_SKB_CACHE_BULK, + nc->skb_cache); + if (unlikely(!nc->skb_count)) + return NULL; + } + + skb = nc->skb_cache[--nc->skb_count]; + kasan_unpoison_object_data(skbuff_cache, skb); + + return skb; +} + +static inline void __finalize_skb_around(struct sk_buff *skb, void *data, + unsigned int size) +{ + struct skb_shared_info *shinfo; + + size -= SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); + + /* Assumes caller memset cleared SKB */ + skb->truesize = SKB_TRUESIZE(size); + refcount_set(&skb->users, 1); + skb->head = data; + skb->data = data; + skb_reset_tail_pointer(skb); + skb_set_end_offset(skb, size); + skb->mac_header = (typeof(skb->mac_header))~0U; + skb->transport_header = (typeof(skb->transport_header))~0U; + skb->alloc_cpu = raw_smp_processor_id(); + /* make sure we initialize shinfo sequentially */ + shinfo = skb_shinfo(skb); + memset(shinfo, 0, offsetof(struct skb_shared_info, dataref)); + atomic_set(&shinfo->dataref, 1); + + skb_set_kcov_handle(skb, kcov_common_handle()); +} + +static inline void *__slab_build_skb(struct sk_buff *skb, void *data, + unsigned int *size) +{ + void *resized; + + /* Must find the allocation size (and grow it to match). */ + *size = ksize(data); + /* krealloc() will immediately return "data" when + * "ksize(data)" is requested: it is the existing upper + * bounds. As a result, GFP_ATOMIC will be ignored. Note + * that this "new" pointer needs to be passed back to the + * caller for use so the __alloc_size hinting will be + * tracked correctly. + */ + resized = krealloc(data, *size, GFP_ATOMIC); + WARN_ON_ONCE(resized != data); + return resized; +} + +/* build_skb() variant which can operate on slab buffers. + * Note that this should be used sparingly as slab buffers + * cannot be combined efficiently by GRO! + */ +struct sk_buff *slab_build_skb(void *data) +{ + struct sk_buff *skb; + unsigned int size; + + skb = kmem_cache_alloc(skbuff_cache, GFP_ATOMIC); + if (unlikely(!skb)) + return NULL; + + memset(skb, 0, offsetof(struct sk_buff, tail)); + data = __slab_build_skb(skb, data, &size); + __finalize_skb_around(skb, data, size); + + return skb; +} +EXPORT_SYMBOL(slab_build_skb); + +/* Caller must provide SKB that is memset cleared */ +static void __build_skb_around(struct sk_buff *skb, void *data, + unsigned int frag_size) +{ + unsigned int size = frag_size; + + /* frag_size == 0 is considered deprecated now. Callers + * using slab buffer should use slab_build_skb() instead. + */ + if (WARN_ONCE(size == 0, "Use slab_build_skb() instead")) + data = __slab_build_skb(skb, data, &size); + + __finalize_skb_around(skb, data, size); +} + +/** + * __build_skb - build a network buffer + * @data: data buffer provided by caller + * @frag_size: size of data (must not be 0) + * + * Allocate a new &sk_buff. Caller provides space holding head and + * skb_shared_info. @data must have been allocated from the page + * allocator or vmalloc(). (A @frag_size of 0 to indicate a kmalloc() + * allocation is deprecated, and callers should use slab_build_skb() + * instead.) + * 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 sk_buff *skb; + + skb = kmem_cache_alloc(skbuff_cache, GFP_ATOMIC); + if (unlikely(!skb)) + return NULL; + + memset(skb, 0, offsetof(struct sk_buff, tail)); + __build_skb_around(skb, data, frag_size); + + return skb; +} + +/* build_skb() is wrapper over __build_skb(), that specifically + * takes care of skb->head and skb->pfmemalloc + */ +struct sk_buff *build_skb(void *data, unsigned int frag_size) +{ + struct sk_buff *skb = __build_skb(data, frag_size); + + if (likely(skb && frag_size)) { + skb->head_frag = 1; + skb_propagate_pfmemalloc(virt_to_head_page(data), skb); + } + return skb; +} +EXPORT_SYMBOL(build_skb); + +/** + * build_skb_around - build a network buffer around provided skb + * @skb: sk_buff provide by caller, must be memset cleared + * @data: data buffer provided by caller + * @frag_size: size of data + */ +struct sk_buff *build_skb_around(struct sk_buff *skb, + void *data, unsigned int frag_size) +{ + if (unlikely(!skb)) + return NULL; + + __build_skb_around(skb, data, frag_size); + + if (frag_size) { + skb->head_frag = 1; + skb_propagate_pfmemalloc(virt_to_head_page(data), skb); + } + return skb; +} +EXPORT_SYMBOL(build_skb_around); + +/** + * __napi_build_skb - build a network buffer + * @data: data buffer provided by caller + * @frag_size: size of data + * + * Version of __build_skb() that uses NAPI percpu caches to obtain + * skbuff_head instead of inplace allocation. + * + * Returns a new &sk_buff on success, %NULL on allocation failure. + */ +static struct sk_buff *__napi_build_skb(void *data, unsigned int frag_size) +{ + struct sk_buff *skb; + + skb = napi_skb_cache_get(); + if (unlikely(!skb)) + return NULL; + + memset(skb, 0, offsetof(struct sk_buff, tail)); + __build_skb_around(skb, data, frag_size); + + return skb; +} + +/** + * napi_build_skb - build a network buffer + * @data: data buffer provided by caller + * @frag_size: size of data + * + * Version of __napi_build_skb() that takes care of skb->head_frag + * and skb->pfmemalloc when the data is a page or page fragment. + * + * Returns a new &sk_buff on success, %NULL on allocation failure. + */ +struct sk_buff *napi_build_skb(void *data, unsigned int frag_size) +{ + struct sk_buff *skb = __napi_build_skb(data, frag_size); + + if (likely(skb) && frag_size) { + skb->head_frag = 1; + skb_propagate_pfmemalloc(virt_to_head_page(data), skb); + } + + return skb; +} +EXPORT_SYMBOL(napi_build_skb); + +/* + * 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 + */ +static void *kmalloc_reserve(unsigned int *size, gfp_t flags, int node, + bool *pfmemalloc) +{ + bool ret_pfmemalloc = false; + size_t obj_size; + void *obj; + + obj_size = SKB_HEAD_ALIGN(*size); + if (obj_size <= SKB_SMALL_HEAD_CACHE_SIZE && + !(flags & KMALLOC_NOT_NORMAL_BITS)) { + obj = kmem_cache_alloc_node(skb_small_head_cache, + flags | __GFP_NOMEMALLOC | __GFP_NOWARN, + node); + *size = SKB_SMALL_HEAD_CACHE_SIZE; + if (obj || !(gfp_pfmemalloc_allowed(flags))) + goto out; + /* Try again but now we are using pfmemalloc reserves */ + ret_pfmemalloc = true; + obj = kmem_cache_alloc_node(skb_small_head_cache, flags, node); + goto out; + } + + obj_size = kmalloc_size_roundup(obj_size); + /* The following cast might truncate high-order bits of obj_size, this + * is harmless because kmalloc(obj_size >= 2^32) will fail anyway. + */ + *size = (unsigned int)obj_size; + + /* + * Try a regular allocation, when that fails and we're not entitled + * to the reserves, fail. + */ + obj = kmalloc_node_track_caller(obj_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(obj_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. + * + */ + +/** + * __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 sk_buff *skb; + bool pfmemalloc; + u8 *data; + + cache = (flags & SKB_ALLOC_FCLONE) + ? skbuff_fclone_cache : skbuff_cache; + + if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX)) + gfp_mask |= __GFP_MEMALLOC; + + /* Get the HEAD */ + if ((flags & (SKB_ALLOC_FCLONE | SKB_ALLOC_NAPI)) == SKB_ALLOC_NAPI && + likely(node == NUMA_NO_NODE || node == numa_mem_id())) + skb = napi_skb_cache_get(); + else + skb = kmem_cache_alloc_node(cache, gfp_mask & ~GFP_DMA, node); + if (unlikely(!skb)) + return NULL; + 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. + */ + data = kmalloc_reserve(&size, gfp_mask, node, &pfmemalloc); + if (unlikely(!data)) + goto nodata; + /* kmalloc_size_roundup() 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. + */ + prefetchw(data + SKB_WITH_OVERHEAD(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)); + __build_skb_around(skb, data, size); + skb->pfmemalloc = pfmemalloc; + + if (flags & SKB_ALLOC_FCLONE) { + struct sk_buff_fclones *fclones; + + fclones = container_of(skb, struct sk_buff_fclones, skb1); + + skb->fclone = SKB_FCLONE_ORIG; + refcount_set(&fclones->fclone_ref, 1); + } + + return skb; + +nodata: + kmem_cache_free(cache, skb); + return NULL; +} +EXPORT_SYMBOL(__alloc_skb); + +/** + * __netdev_alloc_skb - allocate an skbuff for rx on a specific device + * @dev: network device to receive on + * @len: 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 NET_SKB_PAD 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 len, + gfp_t gfp_mask) +{ + struct page_frag_cache *nc; + struct sk_buff *skb; + bool pfmemalloc; + void *data; + + len += NET_SKB_PAD; + + /* If requested length is either too small or too big, + * we use kmalloc() for skb->head allocation. + */ + if (len <= SKB_WITH_OVERHEAD(1024) || + len > SKB_WITH_OVERHEAD(PAGE_SIZE) || + (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) { + skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE); + if (!skb) + goto skb_fail; + goto skb_success; + } + + len = SKB_HEAD_ALIGN(len); + + if (sk_memalloc_socks()) + gfp_mask |= __GFP_MEMALLOC; + + if (in_hardirq() || irqs_disabled()) { + nc = this_cpu_ptr(&netdev_alloc_cache); + data = page_frag_alloc(nc, len, gfp_mask); + pfmemalloc = nc->pfmemalloc; + } else { + local_bh_disable(); + nc = this_cpu_ptr(&napi_alloc_cache.page); + data = page_frag_alloc(nc, len, gfp_mask); + pfmemalloc = nc->pfmemalloc; + local_bh_enable(); + } + + if (unlikely(!data)) + return NULL; + + skb = __build_skb(data, len); + if (unlikely(!skb)) { + skb_free_frag(data); + return NULL; + } + + if (pfmemalloc) + skb->pfmemalloc = 1; + skb->head_frag = 1; + +skb_success: + skb_reserve(skb, NET_SKB_PAD); + skb->dev = dev; + +skb_fail: + return skb; +} +EXPORT_SYMBOL(__netdev_alloc_skb); + +/** + * __napi_alloc_skb - allocate skbuff for rx in a specific NAPI instance + * @napi: napi instance this buffer was allocated for + * @len: length to allocate + * @gfp_mask: get_free_pages mask, passed to alloc_skb and alloc_pages + * + * Allocate a new sk_buff for use in NAPI receive. This buffer will + * attempt to allocate the head from a special reserved region used + * only for NAPI Rx allocation. By doing this we can save several + * CPU cycles by avoiding having to disable and re-enable IRQs. + * + * %NULL is returned if there is no free memory. + */ +struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, unsigned int len, + gfp_t gfp_mask) +{ + struct napi_alloc_cache *nc; + struct sk_buff *skb; + bool pfmemalloc; + void *data; + + DEBUG_NET_WARN_ON_ONCE(!in_softirq()); + len += NET_SKB_PAD + NET_IP_ALIGN; + + /* If requested length is either too small or too big, + * we use kmalloc() for skb->head allocation. + * When the small frag allocator is available, prefer it over kmalloc + * for small fragments + */ + if ((!NAPI_HAS_SMALL_PAGE_FRAG && len <= SKB_WITH_OVERHEAD(1024)) || + len > SKB_WITH_OVERHEAD(PAGE_SIZE) || + (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) { + skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX | SKB_ALLOC_NAPI, + NUMA_NO_NODE); + if (!skb) + goto skb_fail; + goto skb_success; + } + + nc = this_cpu_ptr(&napi_alloc_cache); + + if (sk_memalloc_socks()) + gfp_mask |= __GFP_MEMALLOC; + + if (NAPI_HAS_SMALL_PAGE_FRAG && len <= SKB_WITH_OVERHEAD(1024)) { + /* we are artificially inflating the allocation size, but + * that is not as bad as it may look like, as: + * - 'len' less than GRO_MAX_HEAD makes little sense + * - On most systems, larger 'len' values lead to fragment + * size above 512 bytes + * - kmalloc would use the kmalloc-1k slab for such values + * - Builds with smaller GRO_MAX_HEAD will very likely do + * little networking, as that implies no WiFi and no + * tunnels support, and 32 bits arches. + */ + len = SZ_1K; + + data = page_frag_alloc_1k(&nc->page_small, gfp_mask); + pfmemalloc = NAPI_SMALL_PAGE_PFMEMALLOC(nc->page_small); + } else { + len = SKB_HEAD_ALIGN(len); + + data = page_frag_alloc(&nc->page, len, gfp_mask); + pfmemalloc = nc->page.pfmemalloc; + } + + if (unlikely(!data)) + return NULL; + + skb = __napi_build_skb(data, len); + if (unlikely(!skb)) { + skb_free_frag(data); + return NULL; + } + + if (pfmemalloc) + skb->pfmemalloc = 1; + skb->head_frag = 1; + +skb_success: + skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN); + skb->dev = napi->dev; + +skb_fail: + return skb; +} +EXPORT_SYMBOL(__napi_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); + +void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size, + unsigned int truesize) +{ + skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + + skb_frag_size_add(frag, size); + skb->len += size; + skb->data_len += size; + skb->truesize += truesize; +} +EXPORT_SYMBOL(skb_coalesce_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); +} + +static void skb_clone_fraglist(struct sk_buff *skb) +{ + struct sk_buff *list; + + skb_walk_frags(skb, list) + skb_get(list); +} + +#if IS_ENABLED(CONFIG_PAGE_POOL) +bool napi_pp_put_page(struct page *page, bool napi_safe) +{ + bool allow_direct = false; + struct page_pool *pp; + + page = compound_head(page); + + /* page->pp_magic is OR'ed with PP_SIGNATURE after the allocation + * in order to preserve any existing bits, such as bit 0 for the + * head page of compound page and bit 1 for pfmemalloc page, so + * mask those bits for freeing side when doing below checking, + * and page_is_pfmemalloc() is checked in __page_pool_put_page() + * to avoid recycling the pfmemalloc page. + */ + if (unlikely((page->pp_magic & ~0x3UL) != PP_SIGNATURE)) + return false; + + pp = page->pp; + + /* Allow direct recycle if we have reasons to believe that we are + * in the same context as the consumer would run, so there's + * no possible race. + * __page_pool_put_page() makes sure we're not in hardirq context + * and interrupts are enabled prior to accessing the cache. + */ + if (napi_safe || in_softirq()) { + const struct napi_struct *napi = READ_ONCE(pp->p.napi); + + allow_direct = napi && + READ_ONCE(napi->list_owner) == smp_processor_id(); + } + + /* Driver set this to memory recycling info. Reset it on recycle. + * This will *not* work for NIC using a split-page memory model. + * The page will be returned to the pool here regardless of the + * 'flipped' fragment being in use or not. + */ + page_pool_put_full_page(pp, page, allow_direct); + + return true; +} +EXPORT_SYMBOL(napi_pp_put_page); +#endif + +static bool skb_pp_recycle(struct sk_buff *skb, void *data, bool napi_safe) +{ + if (!IS_ENABLED(CONFIG_PAGE_POOL) || !skb->pp_recycle) + return false; + return napi_pp_put_page(virt_to_page(data), napi_safe); +} + +static void skb_kfree_head(void *head, unsigned int end_offset) +{ + if (end_offset == SKB_SMALL_HEAD_HEADROOM) + kmem_cache_free(skb_small_head_cache, head); + else + kfree(head); +} + +static void skb_free_head(struct sk_buff *skb, bool napi_safe) +{ + unsigned char *head = skb->head; + + if (skb->head_frag) { + if (skb_pp_recycle(skb, head, napi_safe)) + return; + skb_free_frag(head); + } else { + skb_kfree_head(head, skb_end_offset(skb)); + } +} + +static void skb_release_data(struct sk_buff *skb, enum skb_drop_reason reason, + bool napi_safe) +{ + struct skb_shared_info *shinfo = skb_shinfo(skb); + int i; + + if (skb->cloned && + atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1, + &shinfo->dataref)) + goto exit; + + if (skb_zcopy(skb)) { + bool skip_unref = shinfo->flags & SKBFL_MANAGED_FRAG_REFS; + + skb_zcopy_clear(skb, true); + if (skip_unref) + goto free_head; + } + + for (i = 0; i < shinfo->nr_frags; i++) + napi_frag_unref(&shinfo->frags[i], skb->pp_recycle, napi_safe); + +free_head: + if (shinfo->frag_list) + kfree_skb_list_reason(shinfo->frag_list, reason); + + skb_free_head(skb, napi_safe); +exit: + /* When we clone an SKB we copy the reycling bit. The pp_recycle + * bit is only set on the head though, so in order to avoid races + * while trying to recycle fragments on __skb_frag_unref() we need + * to make one SKB responsible for triggering the recycle path. + * So disable the recycling bit if an SKB is cloned and we have + * additional references to the fragmented part of the SKB. + * Eventually the last SKB will have the recycling bit set and it's + * dataref set to 0, which will trigger the recycling + */ + skb->pp_recycle = 0; +} + +/* + * Free an skbuff by memory without cleaning the state. + */ +static void kfree_skbmem(struct sk_buff *skb) +{ + struct sk_buff_fclones *fclones; + + switch (skb->fclone) { + case SKB_FCLONE_UNAVAILABLE: + kmem_cache_free(skbuff_cache, skb); + return; + + case SKB_FCLONE_ORIG: + fclones = container_of(skb, struct sk_buff_fclones, skb1); + + /* We usually free the clone (TX completion) before original skb + * This test would have no chance to be true for the clone, + * while here, branch prediction will be good. + */ + if (refcount_read(&fclones->fclone_ref) == 1) + goto fastpath; + break; + + default: /* SKB_FCLONE_CLONE */ + fclones = container_of(skb, struct sk_buff_fclones, skb2); + break; + } + if (!refcount_dec_and_test(&fclones->fclone_ref)) + return; +fastpath: + kmem_cache_free(skbuff_fclone_cache, fclones); +} + +void skb_release_head_state(struct sk_buff *skb) +{ + skb_dst_drop(skb); + if (skb->destructor) { + DEBUG_NET_WARN_ON_ONCE(in_hardirq()); + skb->destructor(skb); + } +#if IS_ENABLED(CONFIG_NF_CONNTRACK) + nf_conntrack_put(skb_nfct(skb)); +#endif + skb_ext_put(skb); +} + +/* Free everything but the sk_buff shell. */ +static void skb_release_all(struct sk_buff *skb, enum skb_drop_reason reason, + bool napi_safe) +{ + skb_release_head_state(skb); + if (likely(skb->head)) + skb_release_data(skb, reason, napi_safe); +} + +/** + * __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, SKB_DROP_REASON_NOT_SPECIFIED, false); + kfree_skbmem(skb); +} +EXPORT_SYMBOL(__kfree_skb); + +static __always_inline +bool __kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason) +{ + if (unlikely(!skb_unref(skb))) + return false; + + DEBUG_NET_WARN_ON_ONCE(reason == SKB_NOT_DROPPED_YET || + u32_get_bits(reason, + SKB_DROP_REASON_SUBSYS_MASK) >= + SKB_DROP_REASON_SUBSYS_NUM); + + if (reason == SKB_CONSUMED) + trace_consume_skb(skb, __builtin_return_address(0)); + else + trace_kfree_skb(skb, __builtin_return_address(0), reason); + return true; +} + +/** + * kfree_skb_reason - free an sk_buff with special reason + * @skb: buffer to free + * @reason: reason why this skb is dropped + * + * Drop a reference to the buffer and free it if the usage count has + * hit zero. Meanwhile, pass the drop reason to 'kfree_skb' + * tracepoint. + */ +void __fix_address +kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason) +{ + if (__kfree_skb_reason(skb, reason)) + __kfree_skb(skb); +} +EXPORT_SYMBOL(kfree_skb_reason); + +#define KFREE_SKB_BULK_SIZE 16 + +struct skb_free_array { + unsigned int skb_count; + void *skb_array[KFREE_SKB_BULK_SIZE]; +}; + +static void kfree_skb_add_bulk(struct sk_buff *skb, + struct skb_free_array *sa, + enum skb_drop_reason reason) +{ + /* if SKB is a clone, don't handle this case */ + if (unlikely(skb->fclone != SKB_FCLONE_UNAVAILABLE)) { + __kfree_skb(skb); + return; + } + + skb_release_all(skb, reason, false); + sa->skb_array[sa->skb_count++] = skb; + + if (unlikely(sa->skb_count == KFREE_SKB_BULK_SIZE)) { + kmem_cache_free_bulk(skbuff_cache, KFREE_SKB_BULK_SIZE, + sa->skb_array); + sa->skb_count = 0; + } +} + +void __fix_address +kfree_skb_list_reason(struct sk_buff *segs, enum skb_drop_reason reason) +{ + struct skb_free_array sa; + + sa.skb_count = 0; + + while (segs) { + struct sk_buff *next = segs->next; + + if (__kfree_skb_reason(segs, reason)) { + skb_poison_list(segs); + kfree_skb_add_bulk(segs, &sa, reason); + } + + segs = next; + } + + if (sa.skb_count) + kmem_cache_free_bulk(skbuff_cache, sa.skb_count, sa.skb_array); +} +EXPORT_SYMBOL(kfree_skb_list_reason); + +/* Dump skb information and contents. + * + * Must only be called from net_ratelimit()-ed paths. + * + * Dumps whole packets if full_pkt, only headers otherwise. + */ +void skb_dump(const char *level, const struct sk_buff *skb, bool full_pkt) +{ + struct skb_shared_info *sh = skb_shinfo(skb); + struct net_device *dev = skb->dev; + struct sock *sk = skb->sk; + struct sk_buff *list_skb; + bool has_mac, has_trans; + int headroom, tailroom; + int i, len, seg_len; + + if (full_pkt) + len = skb->len; + else + len = min_t(int, skb->len, MAX_HEADER + 128); + + headroom = skb_headroom(skb); + tailroom = skb_tailroom(skb); + + has_mac = skb_mac_header_was_set(skb); + has_trans = skb_transport_header_was_set(skb); + + printk("%sskb len=%u headroom=%u headlen=%u tailroom=%u\n" + "mac=(%d,%d) net=(%d,%d) trans=%d\n" + "shinfo(txflags=%u nr_frags=%u gso(size=%hu type=%u segs=%hu))\n" + "csum(0x%x ip_summed=%u complete_sw=%u valid=%u level=%u)\n" + "hash(0x%x sw=%u l4=%u) proto=0x%04x pkttype=%u iif=%d\n", + level, skb->len, headroom, skb_headlen(skb), tailroom, + has_mac ? skb->mac_header : -1, + has_mac ? skb_mac_header_len(skb) : -1, + skb->network_header, + has_trans ? skb_network_header_len(skb) : -1, + has_trans ? skb->transport_header : -1, + sh->tx_flags, sh->nr_frags, + sh->gso_size, sh->gso_type, sh->gso_segs, + skb->csum, skb->ip_summed, skb->csum_complete_sw, + skb->csum_valid, skb->csum_level, + skb->hash, skb->sw_hash, skb->l4_hash, + ntohs(skb->protocol), skb->pkt_type, skb->skb_iif); + + if (dev) + printk("%sdev name=%s feat=%pNF\n", + level, dev->name, &dev->features); + if (sk) + printk("%ssk family=%hu type=%u proto=%u\n", + level, sk->sk_family, sk->sk_type, sk->sk_protocol); + + if (full_pkt && headroom) + print_hex_dump(level, "skb headroom: ", DUMP_PREFIX_OFFSET, + 16, 1, skb->head, headroom, false); + + seg_len = min_t(int, skb_headlen(skb), len); + if (seg_len) + print_hex_dump(level, "skb linear: ", DUMP_PREFIX_OFFSET, + 16, 1, skb->data, seg_len, false); + len -= seg_len; + + if (full_pkt && tailroom) + print_hex_dump(level, "skb tailroom: ", DUMP_PREFIX_OFFSET, + 16, 1, skb_tail_pointer(skb), tailroom, false); + + for (i = 0; len && i < skb_shinfo(skb)->nr_frags; i++) { + skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + u32 p_off, p_len, copied; + struct page *p; + u8 *vaddr; + + skb_frag_foreach_page(frag, skb_frag_off(frag), + skb_frag_size(frag), p, p_off, p_len, + copied) { + seg_len = min_t(int, p_len, len); + vaddr = kmap_atomic(p); + print_hex_dump(level, "skb frag: ", + DUMP_PREFIX_OFFSET, + 16, 1, vaddr + p_off, seg_len, false); + kunmap_atomic(vaddr); + len -= seg_len; + if (!len) + break; + } + } + + if (full_pkt && skb_has_frag_list(skb)) { + printk("skb fraglist:\n"); + skb_walk_frags(skb, list_skb) + skb_dump(level, list_skb, true); + } +} +EXPORT_SYMBOL(skb_dump); + +/** + * 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) { + skb_zcopy_downgrade_managed(skb); + skb_zcopy_clear(skb, true); + } +} +EXPORT_SYMBOL(skb_tx_error); + +#ifdef CONFIG_TRACEPOINTS +/** + * 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 (!skb_unref(skb)) + return; + + trace_consume_skb(skb, __builtin_return_address(0)); + __kfree_skb(skb); +} +EXPORT_SYMBOL(consume_skb); +#endif + +/** + * __consume_stateless_skb - free an skbuff, assuming it is stateless + * @skb: buffer to free + * + * Alike consume_skb(), but this variant assumes that this is the last + * skb reference and all the head states have been already dropped + */ +void __consume_stateless_skb(struct sk_buff *skb) +{ + trace_consume_skb(skb, __builtin_return_address(0)); + skb_release_data(skb, SKB_CONSUMED, false); + kfree_skbmem(skb); +} + +static void napi_skb_cache_put(struct sk_buff *skb) +{ + struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache); + u32 i; + + kasan_poison_object_data(skbuff_cache, skb); + nc->skb_cache[nc->skb_count++] = skb; + + if (unlikely(nc->skb_count == NAPI_SKB_CACHE_SIZE)) { + for (i = NAPI_SKB_CACHE_HALF; i < NAPI_SKB_CACHE_SIZE; i++) + kasan_unpoison_object_data(skbuff_cache, + nc->skb_cache[i]); + + kmem_cache_free_bulk(skbuff_cache, NAPI_SKB_CACHE_HALF, + nc->skb_cache + NAPI_SKB_CACHE_HALF); + nc->skb_count = NAPI_SKB_CACHE_HALF; + } +} + +void __napi_kfree_skb(struct sk_buff *skb, enum skb_drop_reason reason) +{ + skb_release_all(skb, reason, true); + napi_skb_cache_put(skb); +} + +void napi_skb_free_stolen_head(struct sk_buff *skb) +{ + if (unlikely(skb->slow_gro)) { + nf_reset_ct(skb); + skb_dst_drop(skb); + skb_ext_put(skb); + skb_orphan(skb); + skb->slow_gro = 0; + } + napi_skb_cache_put(skb); +} + +void napi_consume_skb(struct sk_buff *skb, int budget) +{ + /* Zero budget indicate non-NAPI context called us, like netpoll */ + if (unlikely(!budget)) { + dev_consume_skb_any(skb); + return; + } + + DEBUG_NET_WARN_ON_ONCE(!in_softirq()); + + if (!skb_unref(skb)) + return; + + /* if reaching here SKB is ready to free */ + trace_consume_skb(skb, __builtin_return_address(0)); + + /* if SKB is a clone, don't handle this case */ + if (skb->fclone != SKB_FCLONE_UNAVAILABLE) { + __kfree_skb(skb); + return; + } + + skb_release_all(skb, SKB_CONSUMED, !!budget); + napi_skb_cache_put(skb); +} +EXPORT_SYMBOL(napi_consume_skb); + +/* Make sure a field is contained by headers group */ +#define CHECK_SKB_FIELD(field) \ + BUILD_BUG_ON(offsetof(struct sk_buff, field) != \ + offsetof(struct sk_buff, headers.field)); \ + +static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old) +{ + new->tstamp = old->tstamp; + /* We do not copy old->sk */ + new->dev = old->dev; + memcpy(new->cb, old->cb, sizeof(old->cb)); + skb_dst_copy(new, old); + __skb_ext_copy(new, old); + __nf_copy(new, old, false); + + /* Note : this field could be in the headers group. + * It is not yet because we do not want to have a 16 bit hole + */ + new->queue_mapping = old->queue_mapping; + + memcpy(&new->headers, &old->headers, sizeof(new->headers)); + CHECK_SKB_FIELD(protocol); + CHECK_SKB_FIELD(csum); + CHECK_SKB_FIELD(hash); + CHECK_SKB_FIELD(priority); + CHECK_SKB_FIELD(skb_iif); + CHECK_SKB_FIELD(vlan_proto); + CHECK_SKB_FIELD(vlan_tci); + CHECK_SKB_FIELD(transport_header); + CHECK_SKB_FIELD(network_header); + CHECK_SKB_FIELD(mac_header); + CHECK_SKB_FIELD(inner_protocol); + CHECK_SKB_FIELD(inner_transport_header); + CHECK_SKB_FIELD(inner_network_header); + CHECK_SKB_FIELD(inner_mac_header); + CHECK_SKB_FIELD(mark); +#ifdef CONFIG_NETWORK_SECMARK + CHECK_SKB_FIELD(secmark); +#endif +#ifdef CONFIG_NET_RX_BUSY_POLL + CHECK_SKB_FIELD(napi_id); +#endif + CHECK_SKB_FIELD(alloc_cpu); +#ifdef CONFIG_XPS + CHECK_SKB_FIELD(sender_cpu); +#endif +#ifdef CONFIG_NET_SCHED + CHECK_SKB_FIELD(tc_index); +#endif + +} + +/* + * 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->peeked = 0; + C(pfmemalloc); + C(pp_recycle); + n->destructor = NULL; + C(tail); + C(end); + C(head); + C(head_frag); + C(data); + C(truesize); + refcount_set(&n->users, 1); + + atomic_inc(&(skb_shinfo(skb)->dataref)); + skb->cloned = 1; + + return n; +#undef C +} + +/** + * alloc_skb_for_msg() - allocate sk_buff to wrap frag list forming a msg + * @first: first sk_buff of the msg + */ +struct sk_buff *alloc_skb_for_msg(struct sk_buff *first) +{ + struct sk_buff *n; + + n = alloc_skb(0, GFP_ATOMIC); + if (!n) + return NULL; + + n->len = first->len; + n->data_len = first->len; + n->truesize = first->truesize; + + skb_shinfo(n)->frag_list = first; + + __copy_skb_header(n, first); + n->destructor = NULL; + + return n; +} +EXPORT_SYMBOL_GPL(alloc_skb_for_msg); + +/** + * 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, SKB_CONSUMED, false); + return __skb_clone(dst, src); +} +EXPORT_SYMBOL_GPL(skb_morph); + +int mm_account_pinned_pages(struct mmpin *mmp, size_t size) +{ + unsigned long max_pg, num_pg, new_pg, old_pg, rlim; + struct user_struct *user; + + if (capable(CAP_IPC_LOCK) || !size) + return 0; + + rlim = rlimit(RLIMIT_MEMLOCK); + if (rlim == RLIM_INFINITY) + return 0; + + num_pg = (size >> PAGE_SHIFT) + 2; /* worst case */ + max_pg = rlim >> PAGE_SHIFT; + user = mmp->user ? : current_user(); + + old_pg = atomic_long_read(&user->locked_vm); + do { + new_pg = old_pg + num_pg; + if (new_pg > max_pg) + return -ENOBUFS; + } while (!atomic_long_try_cmpxchg(&user->locked_vm, &old_pg, new_pg)); + + if (!mmp->user) { + mmp->user = get_uid(user); + mmp->num_pg = num_pg; + } else { + mmp->num_pg += num_pg; + } + + return 0; +} +EXPORT_SYMBOL_GPL(mm_account_pinned_pages); + +void mm_unaccount_pinned_pages(struct mmpin *mmp) +{ + if (mmp->user) { + atomic_long_sub(mmp->num_pg, &mmp->user->locked_vm); + free_uid(mmp->user); + } +} +EXPORT_SYMBOL_GPL(mm_unaccount_pinned_pages); + +static struct ubuf_info *msg_zerocopy_alloc(struct sock *sk, size_t size) +{ + struct ubuf_info_msgzc *uarg; + struct sk_buff *skb; + + WARN_ON_ONCE(!in_task()); + + skb = sock_omalloc(sk, 0, GFP_KERNEL); + if (!skb) + return NULL; + + BUILD_BUG_ON(sizeof(*uarg) > sizeof(skb->cb)); + uarg = (void *)skb->cb; + uarg->mmp.user = NULL; + + if (mm_account_pinned_pages(&uarg->mmp, size)) { + kfree_skb(skb); + return NULL; + } + + uarg->ubuf.callback = msg_zerocopy_callback; + uarg->id = ((u32)atomic_inc_return(&sk->sk_zckey)) - 1; + uarg->len = 1; + uarg->bytelen = size; + uarg->zerocopy = 1; + uarg->ubuf.flags = SKBFL_ZEROCOPY_FRAG | SKBFL_DONT_ORPHAN; + refcount_set(&uarg->ubuf.refcnt, 1); + sock_hold(sk); + + return &uarg->ubuf; +} + +static inline struct sk_buff *skb_from_uarg(struct ubuf_info_msgzc *uarg) +{ + return container_of((void *)uarg, struct sk_buff, cb); +} + +struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size, + struct ubuf_info *uarg) +{ + if (uarg) { + struct ubuf_info_msgzc *uarg_zc; + const u32 byte_limit = 1 << 19; /* limit to a few TSO */ + u32 bytelen, next; + + /* there might be non MSG_ZEROCOPY users */ + if (uarg->callback != msg_zerocopy_callback) + return NULL; + + /* realloc only when socket is locked (TCP, UDP cork), + * so uarg->len and sk_zckey access is serialized + */ + if (!sock_owned_by_user(sk)) { + WARN_ON_ONCE(1); + return NULL; + } + + uarg_zc = uarg_to_msgzc(uarg); + bytelen = uarg_zc->bytelen + size; + if (uarg_zc->len == USHRT_MAX - 1 || bytelen > byte_limit) { + /* TCP can create new skb to attach new uarg */ + if (sk->sk_type == SOCK_STREAM) + goto new_alloc; + return NULL; + } + + next = (u32)atomic_read(&sk->sk_zckey); + if ((u32)(uarg_zc->id + uarg_zc->len) == next) { + if (mm_account_pinned_pages(&uarg_zc->mmp, size)) + return NULL; + uarg_zc->len++; + uarg_zc->bytelen = bytelen; + atomic_set(&sk->sk_zckey, ++next); + + /* no extra ref when appending to datagram (MSG_MORE) */ + if (sk->sk_type == SOCK_STREAM) + net_zcopy_get(uarg); + + return uarg; + } + } + +new_alloc: + return msg_zerocopy_alloc(sk, size); +} +EXPORT_SYMBOL_GPL(msg_zerocopy_realloc); + +static bool skb_zerocopy_notify_extend(struct sk_buff *skb, u32 lo, u16 len) +{ + struct sock_exterr_skb *serr = SKB_EXT_ERR(skb); + u32 old_lo, old_hi; + u64 sum_len; + + old_lo = serr->ee.ee_info; + old_hi = serr->ee.ee_data; + sum_len = old_hi - old_lo + 1ULL + len; + + if (sum_len >= (1ULL << 32)) + return false; + + if (lo != old_hi + 1) + return false; + + serr->ee.ee_data += len; + return true; +} + +static void __msg_zerocopy_callback(struct ubuf_info_msgzc *uarg) +{ + struct sk_buff *tail, *skb = skb_from_uarg(uarg); + struct sock_exterr_skb *serr; + struct sock *sk = skb->sk; + struct sk_buff_head *q; + unsigned long flags; + bool is_zerocopy; + u32 lo, hi; + u16 len; + + mm_unaccount_pinned_pages(&uarg->mmp); + + /* if !len, there was only 1 call, and it was aborted + * so do not queue a completion notification + */ + if (!uarg->len || sock_flag(sk, SOCK_DEAD)) + goto release; + + len = uarg->len; + lo = uarg->id; + hi = uarg->id + len - 1; + is_zerocopy = uarg->zerocopy; + + serr = SKB_EXT_ERR(skb); + memset(serr, 0, sizeof(*serr)); + serr->ee.ee_errno = 0; + serr->ee.ee_origin = SO_EE_ORIGIN_ZEROCOPY; + serr->ee.ee_data = hi; + serr->ee.ee_info = lo; + if (!is_zerocopy) + serr->ee.ee_code |= SO_EE_CODE_ZEROCOPY_COPIED; + + q = &sk->sk_error_queue; + spin_lock_irqsave(&q->lock, flags); + tail = skb_peek_tail(q); + if (!tail || SKB_EXT_ERR(tail)->ee.ee_origin != SO_EE_ORIGIN_ZEROCOPY || + !skb_zerocopy_notify_extend(tail, lo, len)) { + __skb_queue_tail(q, skb); + skb = NULL; + } + spin_unlock_irqrestore(&q->lock, flags); + + sk_error_report(sk); + +release: + consume_skb(skb); + sock_put(sk); +} + +void msg_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *uarg, + bool success) +{ + struct ubuf_info_msgzc *uarg_zc = uarg_to_msgzc(uarg); + + uarg_zc->zerocopy = uarg_zc->zerocopy & success; + + if (refcount_dec_and_test(&uarg->refcnt)) + __msg_zerocopy_callback(uarg_zc); +} +EXPORT_SYMBOL_GPL(msg_zerocopy_callback); + +void msg_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref) +{ + struct sock *sk = skb_from_uarg(uarg_to_msgzc(uarg))->sk; + + atomic_dec(&sk->sk_zckey); + uarg_to_msgzc(uarg)->len--; + + if (have_uref) + msg_zerocopy_callback(NULL, uarg, true); +} +EXPORT_SYMBOL_GPL(msg_zerocopy_put_abort); + +int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb, + struct msghdr *msg, int len, + struct ubuf_info *uarg) +{ + struct ubuf_info *orig_uarg = skb_zcopy(skb); + int err, orig_len = skb->len; + + /* An skb can only point to one uarg. This edge case happens when + * TCP appends to an skb, but zerocopy_realloc triggered a new alloc. + */ + if (orig_uarg && uarg != orig_uarg) + return -EEXIST; + + err = __zerocopy_sg_from_iter(msg, sk, skb, &msg->msg_iter, len); + if (err == -EFAULT || (err == -EMSGSIZE && skb->len == orig_len)) { + struct sock *save_sk = skb->sk; + + /* Streams do not free skb on error. Reset to prev state. */ + iov_iter_revert(&msg->msg_iter, skb->len - orig_len); + skb->sk = sk; + ___pskb_trim(skb, orig_len); + skb->sk = save_sk; + return err; + } + + skb_zcopy_set(skb, uarg, NULL); + return skb->len - orig_len; +} +EXPORT_SYMBOL_GPL(skb_zerocopy_iter_stream); + +void __skb_zcopy_downgrade_managed(struct sk_buff *skb) +{ + int i; + + skb_shinfo(skb)->flags &= ~SKBFL_MANAGED_FRAG_REFS; + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) + skb_frag_ref(skb, i); +} +EXPORT_SYMBOL_GPL(__skb_zcopy_downgrade_managed); + +static int skb_zerocopy_clone(struct sk_buff *nskb, struct sk_buff *orig, + gfp_t gfp_mask) +{ + if (skb_zcopy(orig)) { + if (skb_zcopy(nskb)) { + /* !gfp_mask callers are verified to !skb_zcopy(nskb) */ + if (!gfp_mask) { + WARN_ON_ONCE(1); + return -ENOMEM; + } + if (skb_uarg(nskb) == skb_uarg(orig)) + return 0; + if (skb_copy_ubufs(nskb, GFP_ATOMIC)) + return -EIO; + } + skb_zcopy_set(nskb, skb_uarg(orig), NULL); + } + return 0; +} + +/** + * skb_copy_ubufs - copy userspace skb frags buffers to kernel + * @skb: the skb to modify + * @gfp_mask: allocation priority + * + * This must be called on skb with SKBFL_ZEROCOPY_ENABLE. + * 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 num_frags = skb_shinfo(skb)->nr_frags; + struct page *page, *head = NULL; + int i, order, psize, new_frags; + u32 d_off; + + if (skb_shared(skb) || skb_unclone(skb, gfp_mask)) + return -EINVAL; + + if (!num_frags) + goto release; + + /* We might have to allocate high order pages, so compute what minimum + * page order is needed. + */ + order = 0; + while ((PAGE_SIZE << order) * MAX_SKB_FRAGS < __skb_pagelen(skb)) + order++; + psize = (PAGE_SIZE << order); + + new_frags = (__skb_pagelen(skb) + psize - 1) >> (PAGE_SHIFT + order); + for (i = 0; i < new_frags; i++) { + page = alloc_pages(gfp_mask | __GFP_COMP, order); + if (!page) { + while (head) { + struct page *next = (struct page *)page_private(head); + put_page(head); + head = next; + } + return -ENOMEM; + } + set_page_private(page, (unsigned long)head); + head = page; + } + + page = head; + d_off = 0; + for (i = 0; i < num_frags; i++) { + skb_frag_t *f = &skb_shinfo(skb)->frags[i]; + u32 p_off, p_len, copied; + struct page *p; + u8 *vaddr; + + skb_frag_foreach_page(f, skb_frag_off(f), skb_frag_size(f), + p, p_off, p_len, copied) { + u32 copy, done = 0; + vaddr = kmap_atomic(p); + + while (done < p_len) { + if (d_off == psize) { + d_off = 0; + page = (struct page *)page_private(page); + } + copy = min_t(u32, psize - d_off, p_len - done); + memcpy(page_address(page) + d_off, + vaddr + p_off + done, copy); + done += copy; + d_off += copy; + } + kunmap_atomic(vaddr); + } + } + + /* skb frags release userspace buffers */ + for (i = 0; i < num_frags; i++) + skb_frag_unref(skb, i); + + /* skb frags point to kernel buffers */ + for (i = 0; i < new_frags - 1; i++) { + __skb_fill_page_desc(skb, i, head, 0, psize); + head = (struct page *)page_private(head); + } + __skb_fill_page_desc(skb, new_frags - 1, head, 0, d_off); + skb_shinfo(skb)->nr_frags = new_frags; + +release: + skb_zcopy_clear(skb, false); + 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_fclones *fclones = container_of(skb, + struct sk_buff_fclones, + skb1); + struct sk_buff *n; + + if (skb_orphan_frags(skb, gfp_mask)) + return NULL; + + if (skb->fclone == SKB_FCLONE_ORIG && + refcount_read(&fclones->fclone_ref) == 1) { + n = &fclones->skb2; + refcount_set(&fclones->fclone_ref, 2); + n->fclone = SKB_FCLONE_CLONE; + } else { + if (skb_pfmemalloc(skb)) + gfp_mask |= __GFP_MEMALLOC; + + n = kmem_cache_alloc(skbuff_cache, gfp_mask); + if (!n) + return NULL; + + n->fclone = SKB_FCLONE_UNAVAILABLE; + } + + return __skb_clone(n, skb); +} +EXPORT_SYMBOL(skb_clone); + +void skb_headers_offset_update(struct sk_buff *skb, int off) +{ + /* Only adjust this if it actually is csum_start rather than csum */ + if (skb->ip_summed == CHECKSUM_PARTIAL) + skb->csum_start += 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; +} +EXPORT_SYMBOL(skb_headers_offset_update); + +void skb_copy_header(struct sk_buff *new, const struct sk_buff *old) +{ + __copy_skb_header(new, old); + + 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(skb_copy_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); + + BUG_ON(skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len)); + + skb_copy_header(n, skb); + return n; +} +EXPORT_SYMBOL(skb_copy); + +/** + * __pskb_copy_fclone - create copy of an sk_buff with private head. + * @skb: buffer to copy + * @headroom: headroom of new skb + * @gfp_mask: allocation priority + * @fclone: if true allocate the copy of the skb from the fclone + * cache instead of the head cache; it is recommended to set this + * to true for the cases where the copy will likely be cloned + * + * 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_fclone(struct sk_buff *skb, int headroom, + gfp_t gfp_mask, bool fclone) +{ + unsigned int size = skb_headlen(skb) + headroom; + int flags = skb_alloc_rx_flag(skb) | (fclone ? SKB_ALLOC_FCLONE : 0); + struct sk_buff *n = __alloc_skb(size, gfp_mask, flags, 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) || + skb_zerocopy_clone(n, 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); + } + + skb_copy_header(n, skb); +out: + return n; +} +EXPORT_SYMBOL(__pskb_copy_fclone); + +/** + * 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) +{ + unsigned int osize = skb_end_offset(skb); + unsigned int size = osize + nhead + ntail; + long off; + u8 *data; + int i; + + BUG_ON(nhead < 0); + + BUG_ON(skb_shared(skb)); + + skb_zcopy_downgrade_managed(skb); + + if (skb_pfmemalloc(skb)) + gfp_mask |= __GFP_MEMALLOC; + + data = kmalloc_reserve(&size, gfp_mask, NUMA_NO_NODE, NULL); + if (!data) + goto nodata; + size = SKB_WITH_OVERHEAD(size); + + /* 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)) { + if (skb_orphan_frags(skb, gfp_mask)) + goto nofrags; + if (skb_zcopy(skb)) + refcount_inc(&skb_uarg(skb)->refcnt); + 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, SKB_CONSUMED, false); + } else { + skb_free_head(skb, false); + } + off = (data + nhead) - skb->head; + + skb->head = data; + skb->head_frag = 0; + skb->data += off; + + skb_set_end_offset(skb, size); +#ifdef NET_SKBUFF_DATA_USES_OFFSET + off = nhead; +#endif + skb->tail += off; + skb_headers_offset_update(skb, nhead); + skb->cloned = 0; + skb->hdr_len = 0; + skb->nohdr = 0; + atomic_set(&skb_shinfo(skb)->dataref, 1); + + skb_metadata_clear(skb); + + /* It is not generally safe to change skb->truesize. + * For the moment, we really care of rx path, or + * when skb is orphaned (not attached to a socket). + */ + if (!skb->sk || skb->destructor == sock_edemux) + skb->truesize += size - osize; + + return 0; + +nofrags: + skb_kfree_head(data, size); +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); + +/* Note: We plan to rework this in linux-6.4 */ +int __skb_unclone_keeptruesize(struct sk_buff *skb, gfp_t pri) +{ + unsigned int saved_end_offset, saved_truesize; + struct skb_shared_info *shinfo; + int res; + + saved_end_offset = skb_end_offset(skb); + saved_truesize = skb->truesize; + + res = pskb_expand_head(skb, 0, 0, pri); + if (res) + return res; + + skb->truesize = saved_truesize; + + if (likely(skb_end_offset(skb) == saved_end_offset)) + return 0; + + /* We can not change skb->end if the original or new value + * is SKB_SMALL_HEAD_HEADROOM, as it might break skb_kfree_head(). + */ + if (saved_end_offset == SKB_SMALL_HEAD_HEADROOM || + skb_end_offset(skb) == SKB_SMALL_HEAD_HEADROOM) { + /* We think this path should not be taken. + * Add a temporary trace to warn us just in case. + */ + pr_err_once("__skb_unclone_keeptruesize() skb_end_offset() %u -> %u\n", + saved_end_offset, skb_end_offset(skb)); + WARN_ON_ONCE(1); + return 0; + } + + shinfo = skb_shinfo(skb); + + /* We are about to change back skb->end, + * we need to move skb_shinfo() to its new location. + */ + memmove(skb->head + saved_end_offset, + shinfo, + offsetof(struct skb_shared_info, frags[shinfo->nr_frags])); + + skb_set_end_offset(skb, saved_end_offset); + + return 0; +} + +/** + * skb_expand_head - reallocate header of &sk_buff + * @skb: buffer to reallocate + * @headroom: needed headroom + * + * Unlike skb_realloc_headroom, this one does not allocate a new skb + * if possible; copies skb->sk to new skb as needed + * and frees original skb in case of failures. + * + * It expect increased headroom and generates warning otherwise. + */ + +struct sk_buff *skb_expand_head(struct sk_buff *skb, unsigned int headroom) +{ + int delta = headroom - skb_headroom(skb); + int osize = skb_end_offset(skb); + struct sock *sk = skb->sk; + + if (WARN_ONCE(delta <= 0, + "%s is expecting an increase in the headroom", __func__)) + return skb; + + delta = SKB_DATA_ALIGN(delta); + /* pskb_expand_head() might crash, if skb is shared. */ + if (skb_shared(skb) || !is_skb_wmem(skb)) { + struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC); + + if (unlikely(!nskb)) + goto fail; + + if (sk) + skb_set_owner_w(nskb, sk); + consume_skb(skb); + skb = nskb; + } + if (pskb_expand_head(skb, delta, 0, GFP_ATOMIC)) + goto fail; + + if (sk && is_skb_wmem(skb)) { + delta = skb_end_offset(skb) - osize; + refcount_add(delta, &sk->sk_wmem_alloc); + skb->truesize += delta; + } + return skb; + +fail: + kfree_skb(skb); + return NULL; +} +EXPORT_SYMBOL(skb_expand_head); + +/** + * 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; + + 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. */ + BUG_ON(skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off, + skb->len + head_copy_len)); + + skb_copy_header(n, skb); + + skb_headers_offset_update(n, newheadroom - oldheadroom); + + return n; +} +EXPORT_SYMBOL(skb_copy_expand); + +/** + * __skb_pad - zero pad the tail of an skb + * @skb: buffer to pad + * @pad: space to pad + * @free_on_error: free buffer on error + * + * 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 + * if @free_on_error is true. + */ + +int __skb_pad(struct sk_buff *skb, int pad, bool free_on_error) +{ + 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: + if (free_on_error) + kfree_skb(skb); + return err; +} +EXPORT_SYMBOL(__skb_pad); + +/** + * pskb_put - add data to the tail of a potentially fragmented buffer + * @skb: start of the buffer to use + * @tail: tail fragment of the buffer to use + * @len: amount of data to add + * + * This function extends the used data area of the potentially + * fragmented buffer. @tail must be the last fragment of @skb -- or + * @skb itself. If this would exceed the total buffer size the kernel + * will panic. A pointer to the first byte of the extra data is + * returned. + */ + +void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len) +{ + if (tail != skb) { + skb->data_len += len; + skb->len += len; + } + return skb_put(tail, len); +} +EXPORT_SYMBOL_GPL(pskb_put); + +/** + * 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. + */ +void *skb_put(struct sk_buff *skb, unsigned int len) +{ + void *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. + */ +void *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. + */ +void *skb_pull(struct sk_buff *skb, unsigned int len) +{ + return skb_pull_inline(skb, len); +} +EXPORT_SYMBOL(skb_pull); + +/** + * skb_pull_data - remove data from the start of a buffer returning its + * original position. + * @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 original data in the buffer + * is returned after checking if there is enough data to pull. Once the + * data has been pulled future pushes will overwrite the old data. + */ +void *skb_pull_data(struct sk_buff *skb, size_t len) +{ + void *data = skb->data; + + if (skb->len < len) + return NULL; + + skb_pull(skb, len); + + return data; +} +EXPORT_SYMBOL(skb_pull_data); + +/** + * 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); + } + + if (!skb->sk || skb->destructor == sock_edemux) + skb_condense(skb); + return 0; +} +EXPORT_SYMBOL(___pskb_trim); + +/* Note : use pskb_trim_rcsum() instead of calling this directly + */ +int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len) +{ + if (skb->ip_summed == CHECKSUM_COMPLETE) { + int delta = skb->len - len; + + skb->csum = csum_block_sub(skb->csum, + skb_checksum(skb, len, delta, 0), + len); + } else if (skb->ip_summed == CHECKSUM_PARTIAL) { + int hdlen = (len > skb_headlen(skb)) ? skb_headlen(skb) : len; + int offset = skb_checksum_start_offset(skb) + skb->csum_offset; + + if (offset + sizeof(__sum16) > hdlen) + return -EINVAL; + } + return __pskb_trim(skb, len); +} +EXPORT_SYMBOL(pskb_trim_rcsum_slow); + +/** + * __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. + */ +void *__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; + } + + BUG_ON(skb_copy_bits(skb, skb_headlen(skb), + skb_tail_pointer(skb), delta)); + + /* 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 is possible to add an offset to skb data, + * but taking into account that pulling is expected to + * be very rare operation, it is worth to fight against + * further bloating skb head and crucify ourselves here instead. + * Pure masohism, indeed. 8)8) + */ + if (eat) { + struct sk_buff *list = skb_shinfo(skb)->frag_list; + struct sk_buff *clone = NULL; + struct sk_buff *insp = NULL; + + do { + if (list->len <= eat) { + /* Eaten as whole. */ + eat -= list->len; + list = list->next; + insp = list; + } else { + /* Eaten partially. */ + if (skb_is_gso(skb) && !list->head_frag && + skb_headlen(list)) + skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; + + 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; + consume_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_frag_t *frag = &skb_shinfo(skb)->frags[k]; + + *frag = skb_shinfo(skb)->frags[i]; + if (eat) { + skb_frag_off_add(frag, eat); + skb_frag_size_sub(frag, eat); + if (!i) + goto end; + eat = 0; + } + k++; + } + } + skb_shinfo(skb)->nr_frags = k; + +end: + skb->tail += delta; + skb->data_len -= delta; + + if (!skb->data_len) + skb_zcopy_clear(skb, false); + + 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) { + u32 p_off, p_len, copied; + struct page *p; + u8 *vaddr; + + if (copy > len) + copy = len; + + skb_frag_foreach_page(f, + skb_frag_off(f) + offset - start, + copy, p, p_off, p_len, copied) { + vaddr = kmap_atomic(p); + memcpy(to + copied, vaddr + p_off, p_len); + 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; + struct sk_buff *iter; + + /* 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), + skb_frag_off(f), skb_frag_size(f), + offset, len, spd, false, sk, pipe)) + return true; + } + + skb_walk_frags(skb, iter) { + if (*offset >= iter->len) { + *offset -= iter->len; + continue; + } + /* __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(iter, pipe, offset, len, spd, sk)) + return true; + } + + return false; +} + +/* + * Map data from the skb to a pipe. Should handle both the linear part, + * the fragments, and the frag list. + */ +int skb_splice_bits(struct sk_buff *skb, struct sock *sk, 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, + .ops = &nosteal_pipe_buf_ops, + .spd_release = sock_spd_release, + }; + int ret = 0; + + __skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk); + + if (spd.nr_pages) + ret = splice_to_pipe(pipe, &spd); + + return ret; +} +EXPORT_SYMBOL_GPL(skb_splice_bits); + +static int sendmsg_locked(struct sock *sk, struct msghdr *msg) +{ + struct socket *sock = sk->sk_socket; + size_t size = msg_data_left(msg); + + if (!sock) + return -EINVAL; + + if (!sock->ops->sendmsg_locked) + return sock_no_sendmsg_locked(sk, msg, size); + + return sock->ops->sendmsg_locked(sk, msg, size); +} + +static int sendmsg_unlocked(struct sock *sk, struct msghdr *msg) +{ + struct socket *sock = sk->sk_socket; + + if (!sock) + return -EINVAL; + return sock_sendmsg(sock, msg); +} + +typedef int (*sendmsg_func)(struct sock *sk, struct msghdr *msg); +static int __skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset, + int len, sendmsg_func sendmsg) +{ + unsigned int orig_len = len; + struct sk_buff *head = skb; + unsigned short fragidx; + int slen, ret; + +do_frag_list: + + /* Deal with head data */ + while (offset < skb_headlen(skb) && len) { + struct kvec kv; + struct msghdr msg; + + slen = min_t(int, len, skb_headlen(skb) - offset); + kv.iov_base = skb->data + offset; + kv.iov_len = slen; + memset(&msg, 0, sizeof(msg)); + msg.msg_flags = MSG_DONTWAIT; + + iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &kv, 1, slen); + ret = INDIRECT_CALL_2(sendmsg, sendmsg_locked, + sendmsg_unlocked, sk, &msg); + if (ret <= 0) + goto error; + + offset += ret; + len -= ret; + } + + /* All the data was skb head? */ + if (!len) + goto out; + + /* Make offset relative to start of frags */ + offset -= skb_headlen(skb); + + /* Find where we are in frag list */ + for (fragidx = 0; fragidx < skb_shinfo(skb)->nr_frags; fragidx++) { + skb_frag_t *frag = &skb_shinfo(skb)->frags[fragidx]; + + if (offset < skb_frag_size(frag)) + break; + + offset -= skb_frag_size(frag); + } + + for (; len && fragidx < skb_shinfo(skb)->nr_frags; fragidx++) { + skb_frag_t *frag = &skb_shinfo(skb)->frags[fragidx]; + + slen = min_t(size_t, len, skb_frag_size(frag) - offset); + + while (slen) { + struct bio_vec bvec; + struct msghdr msg = { + .msg_flags = MSG_SPLICE_PAGES | MSG_DONTWAIT, + }; + + bvec_set_page(&bvec, skb_frag_page(frag), slen, + skb_frag_off(frag) + offset); + iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, + slen); + + ret = INDIRECT_CALL_2(sendmsg, sendmsg_locked, + sendmsg_unlocked, sk, &msg); + if (ret <= 0) + goto error; + + len -= ret; + offset += ret; + slen -= ret; + } + + offset = 0; + } + + if (len) { + /* Process any frag lists */ + + if (skb == head) { + if (skb_has_frag_list(skb)) { + skb = skb_shinfo(skb)->frag_list; + goto do_frag_list; + } + } else if (skb->next) { + skb = skb->next; + goto do_frag_list; + } + } + +out: + return orig_len - len; + +error: + return orig_len == len ? ret : orig_len - len; +} + +/* Send skb data on a socket. Socket must be locked. */ +int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset, + int len) +{ + return __skb_send_sock(sk, skb, offset, len, sendmsg_locked); +} +EXPORT_SYMBOL_GPL(skb_send_sock_locked); + +/* Send skb data on a socket. Socket must be unlocked. */ +int skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset, int len) +{ + return __skb_send_sock(sk, skb, offset, len, sendmsg_unlocked); +} + +/** + * 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) { + u32 p_off, p_len, copied; + struct page *p; + u8 *vaddr; + + if (copy > len) + copy = len; + + skb_frag_foreach_page(frag, + skb_frag_off(frag) + offset - start, + copy, p, p_off, p_len, copied) { + vaddr = kmap_atomic(p); + memcpy(vaddr + p_off, from + copied, p_len); + 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, const struct skb_checksum_ops *ops) +{ + 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 = INDIRECT_CALL_1(ops->update, csum_partial_ext, + 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) { + u32 p_off, p_len, copied; + struct page *p; + __wsum csum2; + u8 *vaddr; + + if (copy > len) + copy = len; + + skb_frag_foreach_page(frag, + skb_frag_off(frag) + offset - start, + copy, p, p_off, p_len, copied) { + vaddr = kmap_atomic(p); + csum2 = INDIRECT_CALL_1(ops->update, + csum_partial_ext, + vaddr + p_off, p_len, 0); + kunmap_atomic(vaddr); + csum = INDIRECT_CALL_1(ops->combine, + csum_block_add_ext, csum, + csum2, pos, p_len); + pos += p_len; + } + + if (!(len -= copy)) + return csum; + 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) { + __wsum csum2; + if (copy > len) + copy = len; + csum2 = __skb_checksum(frag_iter, offset - start, + copy, 0, ops); + csum = INDIRECT_CALL_1(ops->combine, csum_block_add_ext, + csum, csum2, pos, copy); + if ((len -= copy) == 0) + return csum; + offset += copy; + pos += copy; + } + start = end; + } + BUG_ON(len); + + return csum; +} +EXPORT_SYMBOL(__skb_checksum); + +__wsum skb_checksum(const struct sk_buff *skb, int offset, + int len, __wsum csum) +{ + const struct skb_checksum_ops ops = { + .update = csum_partial_ext, + .combine = csum_block_add_ext, + }; + + return __skb_checksum(skb, offset, len, csum, &ops); +} +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) +{ + int start = skb_headlen(skb); + int i, copy = start - offset; + struct sk_buff *frag_iter; + int pos = 0; + __wsum csum = 0; + + /* Copy header. */ + if (copy > 0) { + if (copy > len) + copy = len; + csum = csum_partial_copy_nocheck(skb->data + offset, to, + copy); + 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) { + skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + u32 p_off, p_len, copied; + struct page *p; + __wsum csum2; + u8 *vaddr; + + if (copy > len) + copy = len; + + skb_frag_foreach_page(frag, + skb_frag_off(frag) + offset - start, + copy, p, p_off, p_len, copied) { + vaddr = kmap_atomic(p); + csum2 = csum_partial_copy_nocheck(vaddr + p_off, + to + copied, + p_len); + kunmap_atomic(vaddr); + csum = csum_block_add(csum, csum2, pos); + pos += p_len; + } + + if (!(len -= copy)) + return csum; + offset += copy; + to += 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); + 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); + +__sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len) +{ + __sum16 sum; + + sum = csum_fold(skb_checksum(skb, 0, len, skb->csum)); + /* See comments in __skb_checksum_complete(). */ + if (likely(!sum)) { + if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && + !skb->csum_complete_sw) + netdev_rx_csum_fault(skb->dev, skb); + } + if (!skb_shared(skb)) + skb->csum_valid = !sum; + return sum; +} +EXPORT_SYMBOL(__skb_checksum_complete_head); + +/* This function assumes skb->csum already holds pseudo header's checksum, + * which has been changed from the hardware checksum, for example, by + * __skb_checksum_validate_complete(). And, the original skb->csum must + * have been validated unsuccessfully for CHECKSUM_COMPLETE case. + * + * It returns non-zero if the recomputed checksum is still invalid, otherwise + * zero. The new checksum is stored back into skb->csum unless the skb is + * shared. + */ +__sum16 __skb_checksum_complete(struct sk_buff *skb) +{ + __wsum csum; + __sum16 sum; + + csum = skb_checksum(skb, 0, skb->len, 0); + + sum = csum_fold(csum_add(skb->csum, csum)); + /* This check is inverted, because we already knew the hardware + * checksum is invalid before calling this function. So, if the + * re-computed checksum is valid instead, then we have a mismatch + * between the original skb->csum and skb_checksum(). This means either + * the original hardware checksum is incorrect or we screw up skb->csum + * when moving skb->data around. + */ + if (likely(!sum)) { + if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && + !skb->csum_complete_sw) + netdev_rx_csum_fault(skb->dev, skb); + } + + if (!skb_shared(skb)) { + /* Save full packet checksum */ + skb->csum = csum; + skb->ip_summed = CHECKSUM_COMPLETE; + skb->csum_complete_sw = 1; + skb->csum_valid = !sum; + } + + return sum; +} +EXPORT_SYMBOL(__skb_checksum_complete); + +static __wsum warn_crc32c_csum_update(const void *buff, int len, __wsum sum) +{ + net_warn_ratelimited( + "%s: attempt to compute crc32c without libcrc32c.ko\n", + __func__); + return 0; +} + +static __wsum warn_crc32c_csum_combine(__wsum csum, __wsum csum2, + int offset, int len) +{ + net_warn_ratelimited( + "%s: attempt to compute crc32c without libcrc32c.ko\n", + __func__); + return 0; +} + +static const struct skb_checksum_ops default_crc32c_ops = { + .update = warn_crc32c_csum_update, + .combine = warn_crc32c_csum_combine, +}; + +const struct skb_checksum_ops *crc32c_csum_stub __read_mostly = + &default_crc32c_ops; +EXPORT_SYMBOL(crc32c_csum_stub); + + /** + * skb_zerocopy_headlen - Calculate headroom needed for skb_zerocopy() + * @from: source buffer + * + * Calculates the amount of linear headroom needed in the 'to' skb passed + * into skb_zerocopy(). + */ +unsigned int +skb_zerocopy_headlen(const struct sk_buff *from) +{ + unsigned int hlen = 0; + + if (!from->head_frag || + skb_headlen(from) < L1_CACHE_BYTES || + skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS) { + hlen = skb_headlen(from); + if (!hlen) + hlen = from->len; + } + + if (skb_has_frag_list(from)) + hlen = from->len; + + return hlen; +} +EXPORT_SYMBOL_GPL(skb_zerocopy_headlen); + +/** + * skb_zerocopy - Zero copy skb to skb + * @to: destination buffer + * @from: source buffer + * @len: number of bytes to copy from source buffer + * @hlen: size of linear headroom in destination buffer + * + * Copies up to `len` bytes from `from` to `to` by creating references + * to the frags in the source buffer. + * + * The `hlen` as calculated by skb_zerocopy_headlen() specifies the + * headroom in the `to` buffer. + * + * Return value: + * 0: everything is OK + * -ENOMEM: couldn't orphan frags of @from due to lack of memory + * -EFAULT: skb_copy_bits() found some problem with skb geometry + */ +int +skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen) +{ + int i, j = 0; + int plen = 0; /* length of skb->head fragment */ + int ret; + struct page *page; + unsigned int offset; + + BUG_ON(!from->head_frag && !hlen); + + /* dont bother with small payloads */ + if (len <= skb_tailroom(to)) + return skb_copy_bits(from, 0, skb_put(to, len), len); + + if (hlen) { + ret = skb_copy_bits(from, 0, skb_put(to, hlen), hlen); + if (unlikely(ret)) + return ret; + len -= hlen; + } else { + plen = min_t(int, skb_headlen(from), len); + if (plen) { + page = virt_to_head_page(from->head); + offset = from->data - (unsigned char *)page_address(page); + __skb_fill_page_desc(to, 0, page, offset, plen); + get_page(page); + j = 1; + len -= plen; + } + } + + skb_len_add(to, len + plen); + + if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) { + skb_tx_error(from); + return -ENOMEM; + } + skb_zerocopy_clone(to, from, GFP_ATOMIC); + + for (i = 0; i < skb_shinfo(from)->nr_frags; i++) { + int size; + + if (!len) + break; + skb_shinfo(to)->frags[j] = skb_shinfo(from)->frags[i]; + size = min_t(int, skb_frag_size(&skb_shinfo(to)->frags[j]), + len); + skb_frag_size_set(&skb_shinfo(to)->frags[j], size); + len -= size; + skb_frag_ref(to, j); + j++; + } + skb_shinfo(to)->nr_frags = j; + + return 0; +} +EXPORT_SYMBOL_GPL(skb_zerocopy); + +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); + + 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_reason - empty a list + * @list: list to empty + * @reason: drop reason + * + * 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_reason(struct sk_buff_head *list, + enum skb_drop_reason reason) +{ + struct sk_buff *skb; + + while ((skb = skb_dequeue(list)) != NULL) + kfree_skb_reason(skb, reason); +} +EXPORT_SYMBOL(skb_queue_purge_reason); + +/** + * skb_rbtree_purge - empty a skb rbtree + * @root: root of the rbtree to empty + * Return value: the sum of truesizes of all purged skbs. + * + * Delete all buffers on an &sk_buff rbtree. Each buffer is removed from + * the list and one reference dropped. This function does not take + * any lock. Synchronization should be handled by the caller (e.g., TCP + * out-of-order queue is protected by the socket lock). + */ +unsigned int skb_rbtree_purge(struct rb_root *root) +{ + struct rb_node *p = rb_first(root); + unsigned int sum = 0; + + while (p) { + struct sk_buff *skb = rb_entry(p, struct sk_buff, rbnode); + + p = rb_next(p); + rb_erase(&skb->rbnode, root); + sum += skb->truesize; + kfree_skb(skb); + } + return sum; +} + +void skb_errqueue_purge(struct sk_buff_head *list) +{ + struct sk_buff *skb, *next; + struct sk_buff_head kill; + unsigned long flags; + + __skb_queue_head_init(&kill); + + spin_lock_irqsave(&list->lock, flags); + skb_queue_walk_safe(list, skb, next) { + if (SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_ZEROCOPY || + SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) + continue; + __skb_unlink(skb, list); + __skb_queue_tail(&kill, skb); + } + spin_unlock_irqrestore(&list->lock, flags); + __skb_queue_purge(&kill); +} +EXPORT_SYMBOL(skb_errqueue_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); + +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_frag_off_add(&skb_shinfo(skb1)->frags[0], 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); + const int zc_flags = SKBFL_SHARED_FRAG | SKBFL_PURE_ZEROCOPY; + + skb_zcopy_downgrade_managed(skb); + + skb_shinfo(skb1)->flags |= skb_shinfo(skb)->flags & zc_flags; + skb_zerocopy_clone(skb1, skb, 0); + 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_unclone_keeptruesize(skb, 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; + skb_frag_t *fragfrom, *fragto; + + BUG_ON(shiftlen > skb->len); + + if (skb_headlen(skb)) + return 0; + if (skb_zcopy(tgt) || skb_zcopy(skb)) + return 0; + + 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), + skb_frag_off(fragfrom))) { + 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); + skb_frag_off_add(fragfrom, 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); + skb_frag_page_copy(fragto, fragfrom); + skb_frag_off_copy(fragto, fragfrom); + skb_frag_size_set(fragto, todo); + + skb_frag_off_add(fragfrom, 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, skb->pp_recycle); + } + + /* 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; + + skb_len_add(skb, -shiftlen); + skb_len_add(tgt, 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; + st->frag_off = 0; +} +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 sequential + * 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)) { + if (st->frag_data) { + kunmap_atomic(st->frag_data); + st->frag_data = NULL; + } + 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) { + unsigned int pg_idx, pg_off, pg_sz; + + frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx]; + + pg_idx = 0; + pg_off = skb_frag_off(frag); + pg_sz = skb_frag_size(frag); + + if (skb_frag_must_loop(skb_frag_page(frag))) { + pg_idx = (pg_off + st->frag_off) >> PAGE_SHIFT; + pg_off = offset_in_page(pg_off + st->frag_off); + pg_sz = min_t(unsigned int, pg_sz - st->frag_off, + PAGE_SIZE - pg_off); + } + + block_limit = pg_sz + st->stepped_offset; + if (abs_offset < block_limit) { + if (!st->frag_data) + st->frag_data = kmap_atomic(skb_frag_page(frag) + pg_idx); + + *data = (u8 *)st->frag_data + pg_off + + (abs_offset - st->stepped_offset); + + return block_limit - abs_offset; + } + + if (st->frag_data) { + kunmap_atomic(st->frag_data); + st->frag_data = NULL; + } + + st->stepped_offset += pg_sz; + st->frag_off += pg_sz; + if (st->frag_off == skb_frag_size(frag)) { + st->frag_off = 0; + st->frag_idx++; + } + } + + 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 + * + * 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) +{ + unsigned int patlen = config->ops->get_pattern_len(config); + struct ts_state state; + unsigned int ret; + + BUILD_BUG_ON(sizeof(struct skb_seq_state) > sizeof(state.cb)); + + 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 + patlen <= to - from ? ret : UINT_MAX); +} +EXPORT_SYMBOL(skb_find_text); + +int skb_append_pagefrags(struct sk_buff *skb, struct page *page, + int offset, size_t size, size_t max_frags) +{ + int i = skb_shinfo(skb)->nr_frags; + + if (skb_can_coalesce(skb, i, page, offset)) { + skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size); + } else if (i < max_frags) { + skb_zcopy_downgrade_managed(skb); + get_page(page); + skb_fill_page_desc_noacc(skb, i, page, offset, size); + } else { + return -EMSGSIZE; + } + + return 0; +} +EXPORT_SYMBOL_GPL(skb_append_pagefrags); + +/** + * 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. + */ +void *skb_pull_rcsum(struct sk_buff *skb, unsigned int len) +{ + unsigned char *data = skb->data; + + BUG_ON(len > skb->len); + __skb_pull(skb, len); + skb_postpull_rcsum(skb, data, len); + return skb->data; +} +EXPORT_SYMBOL_GPL(skb_pull_rcsum); + +static inline skb_frag_t skb_head_frag_to_page_desc(struct sk_buff *frag_skb) +{ + skb_frag_t head_frag; + struct page *page; + + page = virt_to_head_page(frag_skb->head); + skb_frag_fill_page_desc(&head_frag, page, frag_skb->data - + (unsigned char *)page_address(page), + skb_headlen(frag_skb)); + return head_frag; +} + +struct sk_buff *skb_segment_list(struct sk_buff *skb, + netdev_features_t features, + unsigned int offset) +{ + struct sk_buff *list_skb = skb_shinfo(skb)->frag_list; + unsigned int tnl_hlen = skb_tnl_header_len(skb); + unsigned int delta_truesize = 0; + unsigned int delta_len = 0; + struct sk_buff *tail = NULL; + struct sk_buff *nskb, *tmp; + int len_diff, err; + + skb_push(skb, -skb_network_offset(skb) + offset); + + /* Ensure the head is writeable before touching the shared info */ + err = skb_unclone(skb, GFP_ATOMIC); + if (err) + goto err_linearize; + + skb_shinfo(skb)->frag_list = NULL; + + while (list_skb) { + nskb = list_skb; + list_skb = list_skb->next; + + err = 0; + delta_truesize += nskb->truesize; + if (skb_shared(nskb)) { + tmp = skb_clone(nskb, GFP_ATOMIC); + if (tmp) { + consume_skb(nskb); + nskb = tmp; + err = skb_unclone(nskb, GFP_ATOMIC); + } else { + err = -ENOMEM; + } + } + + if (!tail) + skb->next = nskb; + else + tail->next = nskb; + + if (unlikely(err)) { + nskb->next = list_skb; + goto err_linearize; + } + + tail = nskb; + + delta_len += nskb->len; + + skb_push(nskb, -skb_network_offset(nskb) + offset); + + skb_release_head_state(nskb); + len_diff = skb_network_header_len(nskb) - skb_network_header_len(skb); + __copy_skb_header(nskb, skb); + + skb_headers_offset_update(nskb, skb_headroom(nskb) - skb_headroom(skb)); + nskb->transport_header += len_diff; + skb_copy_from_linear_data_offset(skb, -tnl_hlen, + nskb->data - tnl_hlen, + offset + tnl_hlen); + + if (skb_needs_linearize(nskb, features) && + __skb_linearize(nskb)) + goto err_linearize; + } + + skb->truesize = skb->truesize - delta_truesize; + skb->data_len = skb->data_len - delta_len; + skb->len = skb->len - delta_len; + + skb_gso_reset(skb); + + skb->prev = tail; + + if (skb_needs_linearize(skb, features) && + __skb_linearize(skb)) + goto err_linearize; + + skb_get(skb); + + return skb; + +err_linearize: + kfree_skb_list(skb->next); + skb->next = NULL; + return ERR_PTR(-ENOMEM); +} +EXPORT_SYMBOL_GPL(skb_segment_list); + +/** + * skb_segment - Perform protocol segmentation on skb. + * @head_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 *head_skb, + netdev_features_t features) +{ + struct sk_buff *segs = NULL; + struct sk_buff *tail = NULL; + struct sk_buff *list_skb = skb_shinfo(head_skb)->frag_list; + unsigned int mss = skb_shinfo(head_skb)->gso_size; + unsigned int doffset = head_skb->data - skb_mac_header(head_skb); + unsigned int offset = doffset; + unsigned int tnl_hlen = skb_tnl_header_len(head_skb); + unsigned int partial_segs = 0; + unsigned int headroom; + unsigned int len = head_skb->len; + struct sk_buff *frag_skb; + skb_frag_t *frag; + __be16 proto; + bool csum, sg; + int err = -ENOMEM; + int i = 0; + int nfrags, pos; + + if ((skb_shinfo(head_skb)->gso_type & SKB_GSO_DODGY) && + mss != GSO_BY_FRAGS && mss != skb_headlen(head_skb)) { + struct sk_buff *check_skb; + + for (check_skb = list_skb; check_skb; check_skb = check_skb->next) { + if (skb_headlen(check_skb) && !check_skb->head_frag) { + /* gso_size is untrusted, and we have a frag_list with + * a linear non head_frag item. + * + * If head_skb's headlen does not fit requested gso_size, + * it means that the frag_list members do NOT terminate + * on exact gso_size boundaries. Hence we cannot perform + * skb_frag_t page sharing. Therefore we must fallback to + * copying the frag_list skbs; we do so by disabling SG. + */ + features &= ~NETIF_F_SG; + break; + } + } + } + + __skb_push(head_skb, doffset); + proto = skb_network_protocol(head_skb, NULL); + if (unlikely(!proto)) + return ERR_PTR(-EINVAL); + + sg = !!(features & NETIF_F_SG); + csum = !!can_checksum_protocol(features, proto); + + if (sg && csum && (mss != GSO_BY_FRAGS)) { + if (!(features & NETIF_F_GSO_PARTIAL)) { + struct sk_buff *iter; + unsigned int frag_len; + + if (!list_skb || + !net_gso_ok(features, skb_shinfo(head_skb)->gso_type)) + goto normal; + + /* If we get here then all the required + * GSO features except frag_list are supported. + * Try to split the SKB to multiple GSO SKBs + * with no frag_list. + * Currently we can do that only when the buffers don't + * have a linear part and all the buffers except + * the last are of the same length. + */ + frag_len = list_skb->len; + skb_walk_frags(head_skb, iter) { + if (frag_len != iter->len && iter->next) + goto normal; + if (skb_headlen(iter) && !iter->head_frag) + goto normal; + + len -= iter->len; + } + + if (len != frag_len) + goto normal; + } + + /* GSO partial only requires that we trim off any excess that + * doesn't fit into an MSS sized block, so take care of that + * now. + * Cap len to not accidentally hit GSO_BY_FRAGS. + */ + partial_segs = min(len, GSO_BY_FRAGS - 1U) / mss; + if (partial_segs > 1) + mss *= partial_segs; + else + partial_segs = 0; + } + +normal: + headroom = skb_headroom(head_skb); + pos = skb_headlen(head_skb); + + if (skb_orphan_frags(head_skb, GFP_ATOMIC)) + return ERR_PTR(-ENOMEM); + + nfrags = skb_shinfo(head_skb)->nr_frags; + frag = skb_shinfo(head_skb)->frags; + frag_skb = head_skb; + + do { + struct sk_buff *nskb; + skb_frag_t *nskb_frag; + int hsize; + int size; + + if (unlikely(mss == GSO_BY_FRAGS)) { + len = list_skb->len; + } else { + len = head_skb->len - offset; + if (len > mss) + len = mss; + } + + hsize = skb_headlen(head_skb) - offset; + + if (hsize <= 0 && i >= nfrags && skb_headlen(list_skb) && + (skb_headlen(list_skb) == len || sg)) { + BUG_ON(skb_headlen(list_skb) > len); + + nskb = skb_clone(list_skb, GFP_ATOMIC); + if (unlikely(!nskb)) + goto err; + + i = 0; + nfrags = skb_shinfo(list_skb)->nr_frags; + frag = skb_shinfo(list_skb)->frags; + frag_skb = list_skb; + pos += skb_headlen(list_skb); + + while (pos < offset + len) { + BUG_ON(i >= nfrags); + + size = skb_frag_size(frag); + if (pos + size > offset + len) + break; + + i++; + pos += size; + frag++; + } + + list_skb = list_skb->next; + + if (unlikely(pskb_trim(nskb, len))) { + kfree_skb(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 { + if (hsize < 0) + hsize = 0; + if (hsize > len || !sg) + hsize = len; + + nskb = __alloc_skb(hsize + doffset + headroom, + GFP_ATOMIC, skb_alloc_rx_flag(head_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, head_skb); + + skb_headers_offset_update(nskb, skb_headroom(nskb) - headroom); + skb_reset_mac_len(nskb); + + skb_copy_from_linear_data_offset(head_skb, -tnl_hlen, + nskb->data - tnl_hlen, + doffset + tnl_hlen); + + if (nskb->len == len + doffset) + goto perform_csum_check; + + if (!sg) { + if (!csum) { + if (!nskb->remcsum_offload) + nskb->ip_summed = CHECKSUM_NONE; + SKB_GSO_CB(nskb)->csum = + skb_copy_and_csum_bits(head_skb, offset, + skb_put(nskb, + len), + len); + SKB_GSO_CB(nskb)->csum_start = + skb_headroom(nskb) + doffset; + } else { + if (skb_copy_bits(head_skb, offset, skb_put(nskb, len), len)) + goto err; + } + continue; + } + + nskb_frag = skb_shinfo(nskb)->frags; + + skb_copy_from_linear_data_offset(head_skb, offset, + skb_put(nskb, hsize), hsize); + + skb_shinfo(nskb)->flags |= skb_shinfo(head_skb)->flags & + SKBFL_SHARED_FRAG; + + if (skb_zerocopy_clone(nskb, frag_skb, GFP_ATOMIC)) + goto err; + + while (pos < offset + len) { + if (i >= nfrags) { + if (skb_orphan_frags(list_skb, GFP_ATOMIC) || + skb_zerocopy_clone(nskb, list_skb, + GFP_ATOMIC)) + goto err; + + i = 0; + nfrags = skb_shinfo(list_skb)->nr_frags; + frag = skb_shinfo(list_skb)->frags; + frag_skb = list_skb; + if (!skb_headlen(list_skb)) { + BUG_ON(!nfrags); + } else { + BUG_ON(!list_skb->head_frag); + + /* to make room for head_frag. */ + i--; + frag--; + } + + list_skb = list_skb->next; + } + + if (unlikely(skb_shinfo(nskb)->nr_frags >= + MAX_SKB_FRAGS)) { + net_warn_ratelimited( + "skb_segment: too many frags: %u %u\n", + pos, mss); + err = -EINVAL; + goto err; + } + + *nskb_frag = (i < 0) ? skb_head_frag_to_page_desc(frag_skb) : *frag; + __skb_frag_ref(nskb_frag); + size = skb_frag_size(nskb_frag); + + if (pos < offset) { + skb_frag_off_add(nskb_frag, offset - pos); + skb_frag_size_sub(nskb_frag, offset - pos); + } + + skb_shinfo(nskb)->nr_frags++; + + if (pos + size <= offset + len) { + i++; + frag++; + pos += size; + } else { + skb_frag_size_sub(nskb_frag, pos + size - (offset + len)); + goto skip_fraglist; + } + + nskb_frag++; + } + +skip_fraglist: + nskb->data_len = len - hsize; + nskb->len += nskb->data_len; + nskb->truesize += nskb->data_len; + +perform_csum_check: + if (!csum) { + if (skb_has_shared_frag(nskb) && + __skb_linearize(nskb)) + goto err; + + if (!nskb->remcsum_offload) + nskb->ip_summed = CHECKSUM_NONE; + SKB_GSO_CB(nskb)->csum = + skb_checksum(nskb, doffset, + nskb->len - doffset, 0); + SKB_GSO_CB(nskb)->csum_start = + skb_headroom(nskb) + doffset; + } + } while ((offset += len) < head_skb->len); + + /* Some callers want to get the end of the list. + * Put it in segs->prev to avoid walking the list. + * (see validate_xmit_skb_list() for example) + */ + segs->prev = tail; + + if (partial_segs) { + struct sk_buff *iter; + int type = skb_shinfo(head_skb)->gso_type; + unsigned short gso_size = skb_shinfo(head_skb)->gso_size; + + /* Update type to add partial and then remove dodgy if set */ + type |= (features & NETIF_F_GSO_PARTIAL) / NETIF_F_GSO_PARTIAL * SKB_GSO_PARTIAL; + type &= ~SKB_GSO_DODGY; + + /* Update GSO info and prepare to start updating headers on + * our way back down the stack of protocols. + */ + for (iter = segs; iter; iter = iter->next) { + skb_shinfo(iter)->gso_size = gso_size; + skb_shinfo(iter)->gso_segs = partial_segs; + skb_shinfo(iter)->gso_type = type; + SKB_GSO_CB(iter)->data_offset = skb_headroom(iter) + doffset; + } + + if (tail->len - doffset <= gso_size) + skb_shinfo(tail)->gso_size = 0; + else if (tail != segs) + skb_shinfo(tail)->gso_segs = DIV_ROUND_UP(tail->len - doffset, gso_size); + } + + /* Following permits correct backpressure, for protocols + * using skb_set_owner_w(). + * Idea is to tranfert ownership from head_skb to last segment. + */ + if (head_skb->destructor == sock_wfree) { + swap(tail->truesize, head_skb->truesize); + swap(tail->destructor, head_skb->destructor); + swap(tail->sk, head_skb->sk); + } + return segs; + +err: + kfree_skb_list(segs); + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(skb_segment); + +#ifdef CONFIG_SKB_EXTENSIONS +#define SKB_EXT_ALIGN_VALUE 8 +#define SKB_EXT_CHUNKSIZEOF(x) (ALIGN((sizeof(x)), SKB_EXT_ALIGN_VALUE) / SKB_EXT_ALIGN_VALUE) + +static const u8 skb_ext_type_len[] = { +#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) + [SKB_EXT_BRIDGE_NF] = SKB_EXT_CHUNKSIZEOF(struct nf_bridge_info), +#endif +#ifdef CONFIG_XFRM + [SKB_EXT_SEC_PATH] = SKB_EXT_CHUNKSIZEOF(struct sec_path), +#endif +#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT) + [TC_SKB_EXT] = SKB_EXT_CHUNKSIZEOF(struct tc_skb_ext), +#endif +#if IS_ENABLED(CONFIG_MPTCP) + [SKB_EXT_MPTCP] = SKB_EXT_CHUNKSIZEOF(struct mptcp_ext), +#endif +#if IS_ENABLED(CONFIG_MCTP_FLOWS) + [SKB_EXT_MCTP] = SKB_EXT_CHUNKSIZEOF(struct mctp_flow), +#endif +}; + +static __always_inline unsigned int skb_ext_total_length(void) +{ + unsigned int l = SKB_EXT_CHUNKSIZEOF(struct skb_ext); + int i; + + for (i = 0; i < ARRAY_SIZE(skb_ext_type_len); i++) + l += skb_ext_type_len[i]; + + return l; +} + +static void skb_extensions_init(void) +{ + BUILD_BUG_ON(SKB_EXT_NUM >= 8); +#if !IS_ENABLED(CONFIG_KCOV_INSTRUMENT_ALL) + BUILD_BUG_ON(skb_ext_total_length() > 255); +#endif + + skbuff_ext_cache = kmem_cache_create("skbuff_ext_cache", + SKB_EXT_ALIGN_VALUE * skb_ext_total_length(), + 0, + SLAB_HWCACHE_ALIGN|SLAB_PANIC, + NULL); +} +#else +static void skb_extensions_init(void) {} +#endif + +/* The SKB kmem_cache slab is critical for network performance. Never + * merge/alias the slab with similar sized objects. This avoids fragmentation + * that hurts performance of kmem_cache_{alloc,free}_bulk APIs. + */ +#ifndef CONFIG_SLUB_TINY +#define FLAG_SKB_NO_MERGE SLAB_NO_MERGE +#else /* CONFIG_SLUB_TINY - simple loop in kmem_cache_alloc_bulk */ +#define FLAG_SKB_NO_MERGE 0 +#endif + +void __init skb_init(void) +{ + skbuff_cache = kmem_cache_create_usercopy("skbuff_head_cache", + sizeof(struct sk_buff), + 0, + SLAB_HWCACHE_ALIGN|SLAB_PANIC| + FLAG_SKB_NO_MERGE, + offsetof(struct sk_buff, cb), + sizeof_field(struct sk_buff, cb), + NULL); + skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache", + sizeof(struct sk_buff_fclones), + 0, + SLAB_HWCACHE_ALIGN|SLAB_PANIC, + NULL); + /* usercopy should only access first SKB_SMALL_HEAD_HEADROOM bytes. + * struct skb_shared_info is located at the end of skb->head, + * and should not be copied to/from user. + */ + skb_small_head_cache = kmem_cache_create_usercopy("skbuff_small_head", + SKB_SMALL_HEAD_CACHE_SIZE, + 0, + SLAB_HWCACHE_ALIGN | SLAB_PANIC, + 0, + SKB_SMALL_HEAD_HEADROOM, + NULL); + skb_extensions_init(); +} + +static int +__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len, + unsigned int recursion_level) +{ + int start = skb_headlen(skb); + int i, copy = start - offset; + struct sk_buff *frag_iter; + int elt = 0; + + if (unlikely(recursion_level >= 24)) + return -EMSGSIZE; + + 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 (unlikely(elt && sg_is_last(&sg[elt - 1]))) + return -EMSGSIZE; + + if (copy > len) + copy = len; + sg_set_page(&sg[elt], skb_frag_page(frag), copy, + skb_frag_off(frag) + offset - start); + elt++; + if (!(len -= copy)) + return elt; + offset += copy; + } + start = end; + } + + skb_walk_frags(skb, frag_iter) { + int end, ret; + + WARN_ON(start > offset + len); + + end = start + frag_iter->len; + if ((copy = end - offset) > 0) { + if (unlikely(elt && sg_is_last(&sg[elt - 1]))) + return -EMSGSIZE; + + if (copy > len) + copy = len; + ret = __skb_to_sgvec(frag_iter, sg+elt, offset - start, + copy, recursion_level + 1); + if (unlikely(ret < 0)) + return ret; + elt += ret; + if ((len -= copy) == 0) + return elt; + offset += copy; + } + start = end; + } + BUG_ON(len); + return elt; +} + +/** + * 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. Returns either + * the number of scatterlist items used, or -EMSGSIZE if the contents + * could not fit. + */ +int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len) +{ + int nsg = __skb_to_sgvec(skb, sg, offset, len, 0); + + if (nsg <= 0) + return nsg; + + sg_mark_end(&sg[nsg - 1]); + + return nsg; +} +EXPORT_SYMBOL_GPL(skb_to_sgvec); + +/* As compared with skb_to_sgvec, skb_to_sgvec_nomark only map skb to given + * sglist without mark the sg which contain last skb data as the end. + * So the caller can mannipulate sg list as will when padding new data after + * the first call without calling sg_unmark_end to expend sg list. + * + * Scenario to use skb_to_sgvec_nomark: + * 1. sg_init_table + * 2. skb_to_sgvec_nomark(payload1) + * 3. skb_to_sgvec_nomark(payload2) + * + * This is equivalent to: + * 1. sg_init_table + * 2. skb_to_sgvec(payload1) + * 3. sg_unmark_end + * 4. skb_to_sgvec(payload2) + * + * When mapping mutilple payload conditionally, skb_to_sgvec_nomark + * is more preferable. + */ +int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg, + int offset, int len) +{ + return __skb_to_sgvec(skb, sg, offset, len, 0); +} +EXPORT_SYMBOL_GPL(skb_to_sgvec_nomark); + + + +/** + * 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))) + 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); +} + +static void skb_set_err_queue(struct sk_buff *skb) +{ + /* pkt_type of skbs received on local sockets is never PACKET_OUTGOING. + * So, it is safe to (mis)use it to mark skbs on the error queue. + */ + skb->pkt_type = PACKET_OUTGOING; + BUILD_BUG_ON(PACKET_OUTGOING == 0); +} + +/* + * Note: We dont mem charge error packets (no sk_forward_alloc changes) + */ +int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb) +{ + if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >= + (unsigned int)READ_ONCE(sk->sk_rcvbuf)) + return -ENOMEM; + + skb_orphan(skb); + skb->sk = sk; + skb->destructor = sock_rmem_free; + atomic_add(skb->truesize, &sk->sk_rmem_alloc); + skb_set_err_queue(skb); + + /* 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_error_report(sk); + return 0; +} +EXPORT_SYMBOL(sock_queue_err_skb); + +static bool is_icmp_err_skb(const struct sk_buff *skb) +{ + return skb && (SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_ICMP || + SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_ICMP6); +} + +struct sk_buff *sock_dequeue_err_skb(struct sock *sk) +{ + struct sk_buff_head *q = &sk->sk_error_queue; + struct sk_buff *skb, *skb_next = NULL; + bool icmp_next = false; + unsigned long flags; + + spin_lock_irqsave(&q->lock, flags); + skb = __skb_dequeue(q); + if (skb && (skb_next = skb_peek(q))) { + icmp_next = is_icmp_err_skb(skb_next); + if (icmp_next) + sk->sk_err = SKB_EXT_ERR(skb_next)->ee.ee_errno; + } + spin_unlock_irqrestore(&q->lock, flags); + + if (is_icmp_err_skb(skb) && !icmp_next) + sk->sk_err = 0; + + if (skb_next) + sk_error_report(sk); + + return skb; +} +EXPORT_SYMBOL(sock_dequeue_err_skb); + +/** + * skb_clone_sk - create clone of skb, and take reference to socket + * @skb: the skb to clone + * + * This function creates a clone of a buffer that holds a reference on + * sk_refcnt. Buffers created via this function are meant to be + * returned using sock_queue_err_skb, or free via kfree_skb. + * + * When passing buffers allocated with this function to sock_queue_err_skb + * it is necessary to wrap the call with sock_hold/sock_put in order to + * prevent the socket from being released prior to being enqueued on + * the sk_error_queue. + */ +struct sk_buff *skb_clone_sk(struct sk_buff *skb) +{ + struct sock *sk = skb->sk; + struct sk_buff *clone; + + if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt)) + return NULL; + + clone = skb_clone(skb, GFP_ATOMIC); + if (!clone) { + sock_put(sk); + return NULL; + } + + clone->sk = sk; + clone->destructor = sock_efree; + + return clone; +} +EXPORT_SYMBOL(skb_clone_sk); + +static void __skb_complete_tx_timestamp(struct sk_buff *skb, + struct sock *sk, + int tstype, + bool opt_stats) +{ + struct sock_exterr_skb *serr; + int err; + + BUILD_BUG_ON(sizeof(struct sock_exterr_skb) > sizeof(skb->cb)); + + serr = SKB_EXT_ERR(skb); + memset(serr, 0, sizeof(*serr)); + serr->ee.ee_errno = ENOMSG; + serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING; + serr->ee.ee_info = tstype; + serr->opt_stats = opt_stats; + serr->header.h4.iif = skb->dev ? skb->dev->ifindex : 0; + if (READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_OPT_ID) { + serr->ee.ee_data = skb_shinfo(skb)->tskey; + if (sk_is_tcp(sk)) + serr->ee.ee_data -= atomic_read(&sk->sk_tskey); + } + + err = sock_queue_err_skb(sk, skb); + + if (err) + kfree_skb(skb); +} + +static bool skb_may_tx_timestamp(struct sock *sk, bool tsonly) +{ + bool ret; + + if (likely(READ_ONCE(sysctl_tstamp_allow_data) || tsonly)) + return true; + + read_lock_bh(&sk->sk_callback_lock); + ret = sk->sk_socket && sk->sk_socket->file && + file_ns_capable(sk->sk_socket->file, &init_user_ns, CAP_NET_RAW); + read_unlock_bh(&sk->sk_callback_lock); + return ret; +} + +void skb_complete_tx_timestamp(struct sk_buff *skb, + struct skb_shared_hwtstamps *hwtstamps) +{ + struct sock *sk = skb->sk; + + if (!skb_may_tx_timestamp(sk, false)) + goto err; + + /* Take a reference to prevent skb_orphan() from freeing the socket, + * but only if the socket refcount is not zero. + */ + if (likely(refcount_inc_not_zero(&sk->sk_refcnt))) { + *skb_hwtstamps(skb) = *hwtstamps; + __skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND, false); + sock_put(sk); + return; + } + +err: + kfree_skb(skb); +} +EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp); + +void __skb_tstamp_tx(struct sk_buff *orig_skb, + const struct sk_buff *ack_skb, + struct skb_shared_hwtstamps *hwtstamps, + struct sock *sk, int tstype) +{ + struct sk_buff *skb; + bool tsonly, opt_stats = false; + u32 tsflags; + + if (!sk) + return; + + tsflags = READ_ONCE(sk->sk_tsflags); + if (!hwtstamps && !(tsflags & SOF_TIMESTAMPING_OPT_TX_SWHW) && + skb_shinfo(orig_skb)->tx_flags & SKBTX_IN_PROGRESS) + return; + + tsonly = tsflags & SOF_TIMESTAMPING_OPT_TSONLY; + if (!skb_may_tx_timestamp(sk, tsonly)) + return; + + if (tsonly) { +#ifdef CONFIG_INET + if ((tsflags & SOF_TIMESTAMPING_OPT_STATS) && + sk_is_tcp(sk)) { + skb = tcp_get_timestamping_opt_stats(sk, orig_skb, + ack_skb); + opt_stats = true; + } else +#endif + skb = alloc_skb(0, GFP_ATOMIC); + } else { + skb = skb_clone(orig_skb, GFP_ATOMIC); + + if (skb_orphan_frags_rx(skb, GFP_ATOMIC)) { + kfree_skb(skb); + return; + } + } + if (!skb) + return; + + if (tsonly) { + skb_shinfo(skb)->tx_flags |= skb_shinfo(orig_skb)->tx_flags & + SKBTX_ANY_TSTAMP; + skb_shinfo(skb)->tskey = skb_shinfo(orig_skb)->tskey; + } + + if (hwtstamps) + *skb_hwtstamps(skb) = *hwtstamps; + else + __net_timestamp(skb); + + __skb_complete_tx_timestamp(skb, sk, tstype, opt_stats); +} +EXPORT_SYMBOL_GPL(__skb_tstamp_tx); + +void skb_tstamp_tx(struct sk_buff *orig_skb, + struct skb_shared_hwtstamps *hwtstamps) +{ + return __skb_tstamp_tx(orig_skb, NULL, hwtstamps, orig_skb->sk, + SCM_TSTAMP_SND); +} +EXPORT_SYMBOL_GPL(skb_tstamp_tx); + +#ifdef CONFIG_WIRELESS +void skb_complete_wifi_ack(struct sk_buff *skb, bool acked) +{ + struct sock *sk = skb->sk; + struct sock_exterr_skb *serr; + int err = 1; + + skb->wifi_acked_valid = 1; + skb->wifi_acked = acked; + + serr = SKB_EXT_ERR(skb); + memset(serr, 0, sizeof(*serr)); + serr->ee.ee_errno = ENOMSG; + serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS; + + /* Take a reference to prevent skb_orphan() from freeing the socket, + * but only if the socket refcount is not zero. + */ + if (likely(refcount_inc_not_zero(&sk->sk_refcnt))) { + err = sock_queue_err_skb(sk, skb); + sock_put(sk); + } + if (err) + kfree_skb(skb); +} +EXPORT_SYMBOL_GPL(skb_complete_wifi_ack); +#endif /* CONFIG_WIRELESS */ + +/** + * 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) +{ + u32 csum_end = (u32)start + (u32)off + sizeof(__sum16); + u32 csum_start = skb_headroom(skb) + (u32)start; + + if (unlikely(csum_start >= U16_MAX || csum_end > skb_headlen(skb))) { + net_warn_ratelimited("bad partial csum: csum=%u/%u headroom=%u headlen=%u\n", + start, off, skb_headroom(skb), skb_headlen(skb)); + return false; + } + skb->ip_summed = CHECKSUM_PARTIAL; + skb->csum_start = csum_start; + skb->csum_offset = off; + skb->transport_header = csum_start; + return true; +} +EXPORT_SYMBOL_GPL(skb_partial_csum_set); + +static int skb_maybe_pull_tail(struct sk_buff *skb, unsigned int len, + unsigned int max) +{ + if (skb_headlen(skb) >= len) + return 0; + + /* If we need to pullup then pullup to the max, so we + * won't need to do it again. + */ + if (max > skb->len) + max = skb->len; + + if (__pskb_pull_tail(skb, max - skb_headlen(skb)) == NULL) + return -ENOMEM; + + if (skb_headlen(skb) < len) + return -EPROTO; + + return 0; +} + +#define MAX_TCP_HDR_LEN (15 * 4) + +static __sum16 *skb_checksum_setup_ip(struct sk_buff *skb, + typeof(IPPROTO_IP) proto, + unsigned int off) +{ + int err; + + switch (proto) { + case IPPROTO_TCP: + err = skb_maybe_pull_tail(skb, off + sizeof(struct tcphdr), + off + MAX_TCP_HDR_LEN); + if (!err && !skb_partial_csum_set(skb, off, + offsetof(struct tcphdr, + check))) + err = -EPROTO; + return err ? ERR_PTR(err) : &tcp_hdr(skb)->check; + + case IPPROTO_UDP: + err = skb_maybe_pull_tail(skb, off + sizeof(struct udphdr), + off + sizeof(struct udphdr)); + if (!err && !skb_partial_csum_set(skb, off, + offsetof(struct udphdr, + check))) + err = -EPROTO; + return err ? ERR_PTR(err) : &udp_hdr(skb)->check; + } + + return ERR_PTR(-EPROTO); +} + +/* This value should be large enough to cover a tagged ethernet header plus + * maximally sized IP and TCP or UDP headers. + */ +#define MAX_IP_HDR_LEN 128 + +static int skb_checksum_setup_ipv4(struct sk_buff *skb, bool recalculate) +{ + unsigned int off; + bool fragment; + __sum16 *csum; + int err; + + fragment = false; + + err = skb_maybe_pull_tail(skb, + sizeof(struct iphdr), + MAX_IP_HDR_LEN); + if (err < 0) + goto out; + + if (ip_is_fragment(ip_hdr(skb))) + fragment = true; + + off = ip_hdrlen(skb); + + err = -EPROTO; + + if (fragment) + goto out; + + csum = skb_checksum_setup_ip(skb, ip_hdr(skb)->protocol, off); + if (IS_ERR(csum)) + return PTR_ERR(csum); + + if (recalculate) + *csum = ~csum_tcpudp_magic(ip_hdr(skb)->saddr, + ip_hdr(skb)->daddr, + skb->len - off, + ip_hdr(skb)->protocol, 0); + err = 0; + +out: + return err; +} + +/* This value should be large enough to cover a tagged ethernet header plus + * an IPv6 header, all options, and a maximal TCP or UDP header. + */ +#define MAX_IPV6_HDR_LEN 256 + +#define OPT_HDR(type, skb, off) \ + (type *)(skb_network_header(skb) + (off)) + +static int skb_checksum_setup_ipv6(struct sk_buff *skb, bool recalculate) +{ + int err; + u8 nexthdr; + unsigned int off; + unsigned int len; + bool fragment; + bool done; + __sum16 *csum; + + fragment = false; + done = false; + + off = sizeof(struct ipv6hdr); + + err = skb_maybe_pull_tail(skb, off, MAX_IPV6_HDR_LEN); + if (err < 0) + goto out; + + nexthdr = ipv6_hdr(skb)->nexthdr; + + len = sizeof(struct ipv6hdr) + ntohs(ipv6_hdr(skb)->payload_len); + while (off <= len && !done) { + switch (nexthdr) { + case IPPROTO_DSTOPTS: + case IPPROTO_HOPOPTS: + case IPPROTO_ROUTING: { + struct ipv6_opt_hdr *hp; + + err = skb_maybe_pull_tail(skb, + off + + sizeof(struct ipv6_opt_hdr), + MAX_IPV6_HDR_LEN); + if (err < 0) + goto out; + + hp = OPT_HDR(struct ipv6_opt_hdr, skb, off); + nexthdr = hp->nexthdr; + off += ipv6_optlen(hp); + break; + } + case IPPROTO_AH: { + struct ip_auth_hdr *hp; + + err = skb_maybe_pull_tail(skb, + off + + sizeof(struct ip_auth_hdr), + MAX_IPV6_HDR_LEN); + if (err < 0) + goto out; + + hp = OPT_HDR(struct ip_auth_hdr, skb, off); + nexthdr = hp->nexthdr; + off += ipv6_authlen(hp); + break; + } + case IPPROTO_FRAGMENT: { + struct frag_hdr *hp; + + err = skb_maybe_pull_tail(skb, + off + + sizeof(struct frag_hdr), + MAX_IPV6_HDR_LEN); + if (err < 0) + goto out; + + hp = OPT_HDR(struct frag_hdr, skb, off); + + if (hp->frag_off & htons(IP6_OFFSET | IP6_MF)) + fragment = true; + + nexthdr = hp->nexthdr; + off += sizeof(struct frag_hdr); + break; + } + default: + done = true; + break; + } + } + + err = -EPROTO; + + if (!done || fragment) + goto out; + + csum = skb_checksum_setup_ip(skb, nexthdr, off); + if (IS_ERR(csum)) + return PTR_ERR(csum); + + if (recalculate) + *csum = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr, + &ipv6_hdr(skb)->daddr, + skb->len - off, nexthdr, 0); + err = 0; + +out: + return err; +} + +/** + * skb_checksum_setup - set up partial checksum offset + * @skb: the skb to set up + * @recalculate: if true the pseudo-header checksum will be recalculated + */ +int skb_checksum_setup(struct sk_buff *skb, bool recalculate) +{ + int err; + + switch (skb->protocol) { + case htons(ETH_P_IP): + err = skb_checksum_setup_ipv4(skb, recalculate); + break; + + case htons(ETH_P_IPV6): + err = skb_checksum_setup_ipv6(skb, recalculate); + break; + + default: + err = -EPROTO; + break; + } + + return err; +} +EXPORT_SYMBOL(skb_checksum_setup); + +/** + * skb_checksum_maybe_trim - maybe trims the given skb + * @skb: the skb to check + * @transport_len: the data length beyond the network header + * + * Checks whether the given skb has data beyond the given transport length. + * If so, returns a cloned skb trimmed to this transport length. + * Otherwise returns the provided skb. Returns NULL in error cases + * (e.g. transport_len exceeds skb length or out-of-memory). + * + * Caller needs to set the skb transport header and free any returned skb if it + * differs from the provided skb. + */ +static struct sk_buff *skb_checksum_maybe_trim(struct sk_buff *skb, + unsigned int transport_len) +{ + struct sk_buff *skb_chk; + unsigned int len = skb_transport_offset(skb) + transport_len; + int ret; + + if (skb->len < len) + return NULL; + else if (skb->len == len) + return skb; + + skb_chk = skb_clone(skb, GFP_ATOMIC); + if (!skb_chk) + return NULL; + + ret = pskb_trim_rcsum(skb_chk, len); + if (ret) { + kfree_skb(skb_chk); + return NULL; + } + + return skb_chk; +} + +/** + * skb_checksum_trimmed - validate checksum of an skb + * @skb: the skb to check + * @transport_len: the data length beyond the network header + * @skb_chkf: checksum function to use + * + * Applies the given checksum function skb_chkf to the provided skb. + * Returns a checked and maybe trimmed skb. Returns NULL on error. + * + * If the skb has data beyond the given transport length, then a + * trimmed & cloned skb is checked and returned. + * + * Caller needs to set the skb transport header and free any returned skb if it + * differs from the provided skb. + */ +struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb, + unsigned int transport_len, + __sum16(*skb_chkf)(struct sk_buff *skb)) +{ + struct sk_buff *skb_chk; + unsigned int offset = skb_transport_offset(skb); + __sum16 ret; + + skb_chk = skb_checksum_maybe_trim(skb, transport_len); + if (!skb_chk) + goto err; + + if (!pskb_may_pull(skb_chk, offset)) + goto err; + + skb_pull_rcsum(skb_chk, offset); + ret = skb_chkf(skb_chk); + skb_push_rcsum(skb_chk, offset); + + if (ret) + goto err; + + return skb_chk; + +err: + if (skb_chk && skb_chk != skb) + kfree_skb(skb_chk); + + return NULL; + +} +EXPORT_SYMBOL(skb_checksum_trimmed); + +void __skb_warn_lro_forwarding(const struct sk_buff *skb) +{ + net_warn_ratelimited("%s: received packets cannot be forwarded while LRO is enabled\n", + skb->dev->name); +} +EXPORT_SYMBOL(__skb_warn_lro_forwarding); + +void kfree_skb_partial(struct sk_buff *skb, bool head_stolen) +{ + if (head_stolen) { + skb_release_head_state(skb); + kmem_cache_free(skbuff_cache, skb); + } else { + __kfree_skb(skb); + } +} +EXPORT_SYMBOL(kfree_skb_partial); + +/** + * skb_try_coalesce - try to merge skb to prior one + * @to: prior buffer + * @from: buffer to add + * @fragstolen: pointer to boolean + * @delta_truesize: how much more was allocated than was requested + */ +bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from, + bool *fragstolen, int *delta_truesize) +{ + struct skb_shared_info *to_shinfo, *from_shinfo; + int i, delta, len = from->len; + + *fragstolen = false; + + if (skb_cloned(to)) + return false; + + /* In general, avoid mixing page_pool and non-page_pool allocated + * pages within the same SKB. Additionally avoid dealing with clones + * with page_pool pages, in case the SKB is using page_pool fragment + * references (PP_FLAG_PAGE_FRAG). Since we only take full page + * references for cloned SKBs at the moment that would result in + * inconsistent reference counts. + * In theory we could take full references if @from is cloned and + * !@to->pp_recycle but its tricky (due to potential race with + * the clone disappearing) and rare, so not worth dealing with. + */ + if (to->pp_recycle != from->pp_recycle || + (from->pp_recycle && skb_cloned(from))) + return false; + + if (len <= skb_tailroom(to)) { + if (len) + BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len)); + *delta_truesize = 0; + return true; + } + + to_shinfo = skb_shinfo(to); + from_shinfo = skb_shinfo(from); + if (to_shinfo->frag_list || from_shinfo->frag_list) + return false; + if (skb_zcopy(to) || skb_zcopy(from)) + return false; + + if (skb_headlen(from) != 0) { + struct page *page; + unsigned int offset; + + if (to_shinfo->nr_frags + + from_shinfo->nr_frags >= MAX_SKB_FRAGS) + return false; + + if (skb_head_is_locked(from)) + return false; + + delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff)); + + page = virt_to_head_page(from->head); + offset = from->data - (unsigned char *)page_address(page); + + skb_fill_page_desc(to, to_shinfo->nr_frags, + page, offset, skb_headlen(from)); + *fragstolen = true; + } else { + if (to_shinfo->nr_frags + + from_shinfo->nr_frags > MAX_SKB_FRAGS) + return false; + + delta = from->truesize - SKB_TRUESIZE(skb_end_offset(from)); + } + + WARN_ON_ONCE(delta < len); + + memcpy(to_shinfo->frags + to_shinfo->nr_frags, + from_shinfo->frags, + from_shinfo->nr_frags * sizeof(skb_frag_t)); + to_shinfo->nr_frags += from_shinfo->nr_frags; + + if (!skb_cloned(from)) + from_shinfo->nr_frags = 0; + + /* if the skb is not cloned this does nothing + * since we set nr_frags to 0. + */ + for (i = 0; i < from_shinfo->nr_frags; i++) + __skb_frag_ref(&from_shinfo->frags[i]); + + to->truesize += delta; + to->len += len; + to->data_len += len; + + *delta_truesize = delta; + return true; +} +EXPORT_SYMBOL(skb_try_coalesce); + +/** + * skb_scrub_packet - scrub an skb + * + * @skb: buffer to clean + * @xnet: packet is crossing netns + * + * skb_scrub_packet can be used after encapsulating or decapsulting a packet + * into/from a tunnel. Some information have to be cleared during these + * operations. + * skb_scrub_packet can also be used to clean a skb before injecting it in + * another namespace (@xnet == true). We have to clear all information in the + * skb that could impact namespace isolation. + */ +void skb_scrub_packet(struct sk_buff *skb, bool xnet) +{ + skb->pkt_type = PACKET_HOST; + skb->skb_iif = 0; + skb->ignore_df = 0; + skb_dst_drop(skb); + skb_ext_reset(skb); + nf_reset_ct(skb); + nf_reset_trace(skb); + +#ifdef CONFIG_NET_SWITCHDEV + skb->offload_fwd_mark = 0; + skb->offload_l3_fwd_mark = 0; +#endif + + if (!xnet) + return; + + ipvs_reset(skb); + skb->mark = 0; + skb_clear_tstamp(skb); +} +EXPORT_SYMBOL_GPL(skb_scrub_packet); + +static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb) +{ + int mac_len, meta_len; + void *meta; + + if (skb_cow(skb, skb_headroom(skb)) < 0) { + kfree_skb(skb); + return NULL; + } + + mac_len = skb->data - skb_mac_header(skb); + if (likely(mac_len > VLAN_HLEN + ETH_TLEN)) { + memmove(skb_mac_header(skb) + VLAN_HLEN, skb_mac_header(skb), + mac_len - VLAN_HLEN - ETH_TLEN); + } + + meta_len = skb_metadata_len(skb); + if (meta_len) { + meta = skb_metadata_end(skb) - meta_len; + memmove(meta + VLAN_HLEN, meta, meta_len); + } + + skb->mac_header += VLAN_HLEN; + return skb; +} + +struct sk_buff *skb_vlan_untag(struct sk_buff *skb) +{ + struct vlan_hdr *vhdr; + u16 vlan_tci; + + if (unlikely(skb_vlan_tag_present(skb))) { + /* vlan_tci is already set-up so leave this for another time */ + return skb; + } + + skb = skb_share_check(skb, GFP_ATOMIC); + if (unlikely(!skb)) + goto err_free; + /* We may access the two bytes after vlan_hdr in vlan_set_encap_proto(). */ + if (unlikely(!pskb_may_pull(skb, VLAN_HLEN + sizeof(unsigned short)))) + goto err_free; + + vhdr = (struct vlan_hdr *)skb->data; + vlan_tci = ntohs(vhdr->h_vlan_TCI); + __vlan_hwaccel_put_tag(skb, skb->protocol, vlan_tci); + + skb_pull_rcsum(skb, VLAN_HLEN); + vlan_set_encap_proto(skb, vhdr); + + skb = skb_reorder_vlan_header(skb); + if (unlikely(!skb)) + goto err_free; + + skb_reset_network_header(skb); + if (!skb_transport_header_was_set(skb)) + skb_reset_transport_header(skb); + skb_reset_mac_len(skb); + + return skb; + +err_free: + kfree_skb(skb); + return NULL; +} +EXPORT_SYMBOL(skb_vlan_untag); + +int skb_ensure_writable(struct sk_buff *skb, unsigned int write_len) +{ + if (!pskb_may_pull(skb, write_len)) + return -ENOMEM; + + if (!skb_cloned(skb) || skb_clone_writable(skb, write_len)) + return 0; + + return pskb_expand_head(skb, 0, 0, GFP_ATOMIC); +} +EXPORT_SYMBOL(skb_ensure_writable); + +/* remove VLAN header from packet and update csum accordingly. + * expects a non skb_vlan_tag_present skb with a vlan tag payload + */ +int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci) +{ + int offset = skb->data - skb_mac_header(skb); + int err; + + if (WARN_ONCE(offset, + "__skb_vlan_pop got skb with skb->data not at mac header (offset %d)\n", + offset)) { + return -EINVAL; + } + + err = skb_ensure_writable(skb, VLAN_ETH_HLEN); + if (unlikely(err)) + return err; + + skb_postpull_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN); + + vlan_remove_tag(skb, vlan_tci); + + skb->mac_header += VLAN_HLEN; + + if (skb_network_offset(skb) < ETH_HLEN) + skb_set_network_header(skb, ETH_HLEN); + + skb_reset_mac_len(skb); + + return err; +} +EXPORT_SYMBOL(__skb_vlan_pop); + +/* Pop a vlan tag either from hwaccel or from payload. + * Expects skb->data at mac header. + */ +int skb_vlan_pop(struct sk_buff *skb) +{ + u16 vlan_tci; + __be16 vlan_proto; + int err; + + if (likely(skb_vlan_tag_present(skb))) { + __vlan_hwaccel_clear_tag(skb); + } else { + if (unlikely(!eth_type_vlan(skb->protocol))) + return 0; + + err = __skb_vlan_pop(skb, &vlan_tci); + if (err) + return err; + } + /* move next vlan tag to hw accel tag */ + if (likely(!eth_type_vlan(skb->protocol))) + return 0; + + vlan_proto = skb->protocol; + err = __skb_vlan_pop(skb, &vlan_tci); + if (unlikely(err)) + return err; + + __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci); + return 0; +} +EXPORT_SYMBOL(skb_vlan_pop); + +/* Push a vlan tag either into hwaccel or into payload (if hwaccel tag present). + * Expects skb->data at mac header. + */ +int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci) +{ + if (skb_vlan_tag_present(skb)) { + int offset = skb->data - skb_mac_header(skb); + int err; + + if (WARN_ONCE(offset, + "skb_vlan_push got skb with skb->data not at mac header (offset %d)\n", + offset)) { + return -EINVAL; + } + + err = __vlan_insert_tag(skb, skb->vlan_proto, + skb_vlan_tag_get(skb)); + if (err) + return err; + + skb->protocol = skb->vlan_proto; + skb->mac_len += VLAN_HLEN; + + skb_postpush_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN); + } + __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci); + return 0; +} +EXPORT_SYMBOL(skb_vlan_push); + +/** + * skb_eth_pop() - Drop the Ethernet header at the head of a packet + * + * @skb: Socket buffer to modify + * + * Drop the Ethernet header of @skb. + * + * Expects that skb->data points to the mac header and that no VLAN tags are + * present. + * + * Returns 0 on success, -errno otherwise. + */ +int skb_eth_pop(struct sk_buff *skb) +{ + if (!pskb_may_pull(skb, ETH_HLEN) || skb_vlan_tagged(skb) || + skb_network_offset(skb) < ETH_HLEN) + return -EPROTO; + + skb_pull_rcsum(skb, ETH_HLEN); + skb_reset_mac_header(skb); + skb_reset_mac_len(skb); + + return 0; +} +EXPORT_SYMBOL(skb_eth_pop); + +/** + * skb_eth_push() - Add a new Ethernet header at the head of a packet + * + * @skb: Socket buffer to modify + * @dst: Destination MAC address of the new header + * @src: Source MAC address of the new header + * + * Prepend @skb with a new Ethernet header. + * + * Expects that skb->data points to the mac header, which must be empty. + * + * Returns 0 on success, -errno otherwise. + */ +int skb_eth_push(struct sk_buff *skb, const unsigned char *dst, + const unsigned char *src) +{ + struct ethhdr *eth; + int err; + + if (skb_network_offset(skb) || skb_vlan_tag_present(skb)) + return -EPROTO; + + err = skb_cow_head(skb, sizeof(*eth)); + if (err < 0) + return err; + + skb_push(skb, sizeof(*eth)); + skb_reset_mac_header(skb); + skb_reset_mac_len(skb); + + eth = eth_hdr(skb); + ether_addr_copy(eth->h_dest, dst); + ether_addr_copy(eth->h_source, src); + eth->h_proto = skb->protocol; + + skb_postpush_rcsum(skb, eth, sizeof(*eth)); + + return 0; +} +EXPORT_SYMBOL(skb_eth_push); + +/* Update the ethertype of hdr and the skb csum value if required. */ +static void skb_mod_eth_type(struct sk_buff *skb, struct ethhdr *hdr, + __be16 ethertype) +{ + if (skb->ip_summed == CHECKSUM_COMPLETE) { + __be16 diff[] = { ~hdr->h_proto, ethertype }; + + skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum); + } + + hdr->h_proto = ethertype; +} + +/** + * skb_mpls_push() - push a new MPLS header after mac_len bytes from start of + * the packet + * + * @skb: buffer + * @mpls_lse: MPLS label stack entry to push + * @mpls_proto: ethertype of the new MPLS header (expects 0x8847 or 0x8848) + * @mac_len: length of the MAC header + * @ethernet: flag to indicate if the resulting packet after skb_mpls_push is + * ethernet + * + * Expects skb->data at mac header. + * + * Returns 0 on success, -errno otherwise. + */ +int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto, + int mac_len, bool ethernet) +{ + struct mpls_shim_hdr *lse; + int err; + + if (unlikely(!eth_p_mpls(mpls_proto))) + return -EINVAL; + + /* Networking stack does not allow simultaneous Tunnel and MPLS GSO. */ + if (skb->encapsulation) + return -EINVAL; + + err = skb_cow_head(skb, MPLS_HLEN); + if (unlikely(err)) + return err; + + if (!skb->inner_protocol) { + skb_set_inner_network_header(skb, skb_network_offset(skb)); + skb_set_inner_protocol(skb, skb->protocol); + } + + skb_push(skb, MPLS_HLEN); + memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb), + mac_len); + skb_reset_mac_header(skb); + skb_set_network_header(skb, mac_len); + skb_reset_mac_len(skb); + + lse = mpls_hdr(skb); + lse->label_stack_entry = mpls_lse; + skb_postpush_rcsum(skb, lse, MPLS_HLEN); + + if (ethernet && mac_len >= ETH_HLEN) + skb_mod_eth_type(skb, eth_hdr(skb), mpls_proto); + skb->protocol = mpls_proto; + + return 0; +} +EXPORT_SYMBOL_GPL(skb_mpls_push); + +/** + * skb_mpls_pop() - pop the outermost MPLS header + * + * @skb: buffer + * @next_proto: ethertype of header after popped MPLS header + * @mac_len: length of the MAC header + * @ethernet: flag to indicate if the packet is ethernet + * + * Expects skb->data at mac header. + * + * Returns 0 on success, -errno otherwise. + */ +int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len, + bool ethernet) +{ + int err; + + if (unlikely(!eth_p_mpls(skb->protocol))) + return 0; + + err = skb_ensure_writable(skb, mac_len + MPLS_HLEN); + if (unlikely(err)) + return err; + + skb_postpull_rcsum(skb, mpls_hdr(skb), MPLS_HLEN); + memmove(skb_mac_header(skb) + MPLS_HLEN, skb_mac_header(skb), + mac_len); + + __skb_pull(skb, MPLS_HLEN); + skb_reset_mac_header(skb); + skb_set_network_header(skb, mac_len); + + if (ethernet && mac_len >= ETH_HLEN) { + struct ethhdr *hdr; + + /* use mpls_hdr() to get ethertype to account for VLANs. */ + hdr = (struct ethhdr *)((void *)mpls_hdr(skb) - ETH_HLEN); + skb_mod_eth_type(skb, hdr, next_proto); + } + skb->protocol = next_proto; + + return 0; +} +EXPORT_SYMBOL_GPL(skb_mpls_pop); + +/** + * skb_mpls_update_lse() - modify outermost MPLS header and update csum + * + * @skb: buffer + * @mpls_lse: new MPLS label stack entry to update to + * + * Expects skb->data at mac header. + * + * Returns 0 on success, -errno otherwise. + */ +int skb_mpls_update_lse(struct sk_buff *skb, __be32 mpls_lse) +{ + int err; + + if (unlikely(!eth_p_mpls(skb->protocol))) + return -EINVAL; + + err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN); + if (unlikely(err)) + return err; + + if (skb->ip_summed == CHECKSUM_COMPLETE) { + __be32 diff[] = { ~mpls_hdr(skb)->label_stack_entry, mpls_lse }; + + skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum); + } + + mpls_hdr(skb)->label_stack_entry = mpls_lse; + + return 0; +} +EXPORT_SYMBOL_GPL(skb_mpls_update_lse); + +/** + * skb_mpls_dec_ttl() - decrement the TTL of the outermost MPLS header + * + * @skb: buffer + * + * Expects skb->data at mac header. + * + * Returns 0 on success, -errno otherwise. + */ +int skb_mpls_dec_ttl(struct sk_buff *skb) +{ + u32 lse; + u8 ttl; + + if (unlikely(!eth_p_mpls(skb->protocol))) + return -EINVAL; + + if (!pskb_may_pull(skb, skb_network_offset(skb) + MPLS_HLEN)) + return -ENOMEM; + + lse = be32_to_cpu(mpls_hdr(skb)->label_stack_entry); + ttl = (lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT; + if (!--ttl) + return -EINVAL; + + lse &= ~MPLS_LS_TTL_MASK; + lse |= ttl << MPLS_LS_TTL_SHIFT; + + return skb_mpls_update_lse(skb, cpu_to_be32(lse)); +} +EXPORT_SYMBOL_GPL(skb_mpls_dec_ttl); + +/** + * alloc_skb_with_frags - allocate skb with page frags + * + * @header_len: size of linear part + * @data_len: needed length in frags + * @order: max page order desired. + * @errcode: pointer to error code if any + * @gfp_mask: allocation mask + * + * This can be used to allocate a paged skb, given a maximal order for frags. + */ +struct sk_buff *alloc_skb_with_frags(unsigned long header_len, + unsigned long data_len, + int order, + int *errcode, + gfp_t gfp_mask) +{ + unsigned long chunk; + struct sk_buff *skb; + struct page *page; + int nr_frags = 0; + + *errcode = -EMSGSIZE; + if (unlikely(data_len > MAX_SKB_FRAGS * (PAGE_SIZE << order))) + return NULL; + + *errcode = -ENOBUFS; + skb = alloc_skb(header_len, gfp_mask); + if (!skb) + return NULL; + + while (data_len) { + if (nr_frags == MAX_SKB_FRAGS - 1) + goto failure; + while (order && PAGE_ALIGN(data_len) < (PAGE_SIZE << order)) + order--; + + if (order) { + page = alloc_pages((gfp_mask & ~__GFP_DIRECT_RECLAIM) | + __GFP_COMP | + __GFP_NOWARN, + order); + if (!page) { + order--; + continue; + } + } else { + page = alloc_page(gfp_mask); + if (!page) + goto failure; + } + chunk = min_t(unsigned long, data_len, + PAGE_SIZE << order); + skb_fill_page_desc(skb, nr_frags, page, 0, chunk); + nr_frags++; + skb->truesize += (PAGE_SIZE << order); + data_len -= chunk; + } + return skb; + +failure: + kfree_skb(skb); + return NULL; +} +EXPORT_SYMBOL(alloc_skb_with_frags); + +/* carve out the first off bytes from skb when off < headlen */ +static int pskb_carve_inside_header(struct sk_buff *skb, const u32 off, + const int headlen, gfp_t gfp_mask) +{ + int i; + unsigned int size = skb_end_offset(skb); + int new_hlen = headlen - off; + u8 *data; + + if (skb_pfmemalloc(skb)) + gfp_mask |= __GFP_MEMALLOC; + + data = kmalloc_reserve(&size, gfp_mask, NUMA_NO_NODE, NULL); + if (!data) + return -ENOMEM; + size = SKB_WITH_OVERHEAD(size); + + /* Copy real data, and all frags */ + skb_copy_from_linear_data_offset(skb, off, data, new_hlen); + skb->len -= off; + + memcpy((struct skb_shared_info *)(data + size), + skb_shinfo(skb), + offsetof(struct skb_shared_info, + frags[skb_shinfo(skb)->nr_frags])); + if (skb_cloned(skb)) { + /* drop the old head gracefully */ + if (skb_orphan_frags(skb, gfp_mask)) { + skb_kfree_head(data, size); + return -ENOMEM; + } + 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, SKB_CONSUMED, false); + } else { + /* we can reuse existing recount- all we did was + * relocate values + */ + skb_free_head(skb, false); + } + + skb->head = data; + skb->data = data; + skb->head_frag = 0; + skb_set_end_offset(skb, size); + skb_set_tail_pointer(skb, skb_headlen(skb)); + skb_headers_offset_update(skb, 0); + skb->cloned = 0; + skb->hdr_len = 0; + skb->nohdr = 0; + atomic_set(&skb_shinfo(skb)->dataref, 1); + + return 0; +} + +static int pskb_carve(struct sk_buff *skb, const u32 off, gfp_t gfp); + +/* carve out the first eat bytes from skb's frag_list. May recurse into + * pskb_carve() + */ +static int pskb_carve_frag_list(struct sk_buff *skb, + struct skb_shared_info *shinfo, int eat, + gfp_t gfp_mask) +{ + struct sk_buff *list = shinfo->frag_list; + struct sk_buff *clone = NULL; + struct sk_buff *insp = NULL; + + do { + if (!list) { + pr_err("Not enough bytes to eat. Want %d\n", eat); + return -EFAULT; + } + if (list->len <= eat) { + /* Eaten as whole. */ + eat -= list->len; + list = list->next; + insp = list; + } else { + /* Eaten partially. */ + if (skb_shared(list)) { + clone = skb_clone(list, gfp_mask); + if (!clone) + return -ENOMEM; + insp = list->next; + list = clone; + } else { + /* This may be pulled without problems. */ + insp = list; + } + if (pskb_carve(list, eat, gfp_mask) < 0) { + kfree_skb(clone); + return -ENOMEM; + } + break; + } + } while (eat); + + /* Free pulled out fragments. */ + while ((list = shinfo->frag_list) != insp) { + shinfo->frag_list = list->next; + consume_skb(list); + } + /* And insert new clone at head. */ + if (clone) { + clone->next = list; + shinfo->frag_list = clone; + } + return 0; +} + +/* carve off first len bytes from skb. Split line (off) is in the + * non-linear part of skb + */ +static int pskb_carve_inside_nonlinear(struct sk_buff *skb, const u32 off, + int pos, gfp_t gfp_mask) +{ + int i, k = 0; + unsigned int size = skb_end_offset(skb); + u8 *data; + const int nfrags = skb_shinfo(skb)->nr_frags; + struct skb_shared_info *shinfo; + + if (skb_pfmemalloc(skb)) + gfp_mask |= __GFP_MEMALLOC; + + data = kmalloc_reserve(&size, gfp_mask, NUMA_NO_NODE, NULL); + if (!data) + return -ENOMEM; + size = SKB_WITH_OVERHEAD(size); + + memcpy((struct skb_shared_info *)(data + size), + skb_shinfo(skb), offsetof(struct skb_shared_info, frags[0])); + if (skb_orphan_frags(skb, gfp_mask)) { + skb_kfree_head(data, size); + return -ENOMEM; + } + shinfo = (struct skb_shared_info *)(data + size); + for (i = 0; i < nfrags; i++) { + int fsize = skb_frag_size(&skb_shinfo(skb)->frags[i]); + + if (pos + fsize > off) { + shinfo->frags[k] = skb_shinfo(skb)->frags[i]; + + if (pos < off) { + /* 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_off_add(&shinfo->frags[0], off - pos); + skb_frag_size_sub(&shinfo->frags[0], off - pos); + } + skb_frag_ref(skb, i); + k++; + } + pos += fsize; + } + shinfo->nr_frags = k; + if (skb_has_frag_list(skb)) + skb_clone_fraglist(skb); + + /* split line is in frag list */ + if (k == 0 && pskb_carve_frag_list(skb, shinfo, off - pos, gfp_mask)) { + /* skb_frag_unref() is not needed here as shinfo->nr_frags = 0. */ + if (skb_has_frag_list(skb)) + kfree_skb_list(skb_shinfo(skb)->frag_list); + skb_kfree_head(data, size); + return -ENOMEM; + } + skb_release_data(skb, SKB_CONSUMED, false); + + skb->head = data; + skb->head_frag = 0; + skb->data = data; + skb_set_end_offset(skb, size); + skb_reset_tail_pointer(skb); + skb_headers_offset_update(skb, 0); + skb->cloned = 0; + skb->hdr_len = 0; + skb->nohdr = 0; + skb->len -= off; + skb->data_len = skb->len; + atomic_set(&skb_shinfo(skb)->dataref, 1); + return 0; +} + +/* remove len bytes from the beginning of the skb */ +static int pskb_carve(struct sk_buff *skb, const u32 len, gfp_t gfp) +{ + int headlen = skb_headlen(skb); + + if (len < headlen) + return pskb_carve_inside_header(skb, len, headlen, gfp); + else + return pskb_carve_inside_nonlinear(skb, len, headlen, gfp); +} + +/* Extract to_copy bytes starting at off from skb, and return this in + * a new skb + */ +struct sk_buff *pskb_extract(struct sk_buff *skb, int off, + int to_copy, gfp_t gfp) +{ + struct sk_buff *clone = skb_clone(skb, gfp); + + if (!clone) + return NULL; + + if (pskb_carve(clone, off, gfp) < 0 || + pskb_trim(clone, to_copy)) { + kfree_skb(clone); + return NULL; + } + return clone; +} +EXPORT_SYMBOL(pskb_extract); + +/** + * skb_condense - try to get rid of fragments/frag_list if possible + * @skb: buffer + * + * Can be used to save memory before skb is added to a busy queue. + * If packet has bytes in frags and enough tail room in skb->head, + * pull all of them, so that we can free the frags right now and adjust + * truesize. + * Notes: + * We do not reallocate skb->head thus can not fail. + * Caller must re-evaluate skb->truesize if needed. + */ +void skb_condense(struct sk_buff *skb) +{ + if (skb->data_len) { + if (skb->data_len > skb->end - skb->tail || + skb_cloned(skb)) + return; + + /* Nice, we can free page frag(s) right now */ + __pskb_pull_tail(skb, skb->data_len); + } + /* At this point, skb->truesize might be over estimated, + * because skb had a fragment, and fragments do not tell + * their truesize. + * When we pulled its content into skb->head, fragment + * was freed, but __pskb_pull_tail() could not possibly + * adjust skb->truesize, not knowing the frag truesize. + */ + skb->truesize = SKB_TRUESIZE(skb_end_offset(skb)); +} +EXPORT_SYMBOL(skb_condense); + +#ifdef CONFIG_SKB_EXTENSIONS +static void *skb_ext_get_ptr(struct skb_ext *ext, enum skb_ext_id id) +{ + return (void *)ext + (ext->offset[id] * SKB_EXT_ALIGN_VALUE); +} + +/** + * __skb_ext_alloc - allocate a new skb extensions storage + * + * @flags: See kmalloc(). + * + * Returns the newly allocated pointer. The pointer can later attached to a + * skb via __skb_ext_set(). + * Note: caller must handle the skb_ext as an opaque data. + */ +struct skb_ext *__skb_ext_alloc(gfp_t flags) +{ + struct skb_ext *new = kmem_cache_alloc(skbuff_ext_cache, flags); + + if (new) { + memset(new->offset, 0, sizeof(new->offset)); + refcount_set(&new->refcnt, 1); + } + + return new; +} + +static struct skb_ext *skb_ext_maybe_cow(struct skb_ext *old, + unsigned int old_active) +{ + struct skb_ext *new; + + if (refcount_read(&old->refcnt) == 1) + return old; + + new = kmem_cache_alloc(skbuff_ext_cache, GFP_ATOMIC); + if (!new) + return NULL; + + memcpy(new, old, old->chunks * SKB_EXT_ALIGN_VALUE); + refcount_set(&new->refcnt, 1); + +#ifdef CONFIG_XFRM + if (old_active & (1 << SKB_EXT_SEC_PATH)) { + struct sec_path *sp = skb_ext_get_ptr(old, SKB_EXT_SEC_PATH); + unsigned int i; + + for (i = 0; i < sp->len; i++) + xfrm_state_hold(sp->xvec[i]); + } +#endif + __skb_ext_put(old); + return new; +} + +/** + * __skb_ext_set - attach the specified extension storage to this skb + * @skb: buffer + * @id: extension id + * @ext: extension storage previously allocated via __skb_ext_alloc() + * + * Existing extensions, if any, are cleared. + * + * Returns the pointer to the extension. + */ +void *__skb_ext_set(struct sk_buff *skb, enum skb_ext_id id, + struct skb_ext *ext) +{ + unsigned int newlen, newoff = SKB_EXT_CHUNKSIZEOF(*ext); + + skb_ext_put(skb); + newlen = newoff + skb_ext_type_len[id]; + ext->chunks = newlen; + ext->offset[id] = newoff; + skb->extensions = ext; + skb->active_extensions = 1 << id; + return skb_ext_get_ptr(ext, id); +} + +/** + * skb_ext_add - allocate space for given extension, COW if needed + * @skb: buffer + * @id: extension to allocate space for + * + * Allocates enough space for the given extension. + * If the extension is already present, a pointer to that extension + * is returned. + * + * If the skb was cloned, COW applies and the returned memory can be + * modified without changing the extension space of clones buffers. + * + * Returns pointer to the extension or NULL on allocation failure. + */ +void *skb_ext_add(struct sk_buff *skb, enum skb_ext_id id) +{ + struct skb_ext *new, *old = NULL; + unsigned int newlen, newoff; + + if (skb->active_extensions) { + old = skb->extensions; + + new = skb_ext_maybe_cow(old, skb->active_extensions); + if (!new) + return NULL; + + if (__skb_ext_exist(new, id)) + goto set_active; + + newoff = new->chunks; + } else { + newoff = SKB_EXT_CHUNKSIZEOF(*new); + + new = __skb_ext_alloc(GFP_ATOMIC); + if (!new) + return NULL; + } + + newlen = newoff + skb_ext_type_len[id]; + new->chunks = newlen; + new->offset[id] = newoff; +set_active: + skb->slow_gro = 1; + skb->extensions = new; + skb->active_extensions |= 1 << id; + return skb_ext_get_ptr(new, id); +} +EXPORT_SYMBOL(skb_ext_add); + +#ifdef CONFIG_XFRM +static void skb_ext_put_sp(struct sec_path *sp) +{ + unsigned int i; + + for (i = 0; i < sp->len; i++) + xfrm_state_put(sp->xvec[i]); +} +#endif + +#ifdef CONFIG_MCTP_FLOWS +static void skb_ext_put_mctp(struct mctp_flow *flow) +{ + if (flow->key) + mctp_key_unref(flow->key); +} +#endif + +void __skb_ext_del(struct sk_buff *skb, enum skb_ext_id id) +{ + struct skb_ext *ext = skb->extensions; + + skb->active_extensions &= ~(1 << id); + if (skb->active_extensions == 0) { + skb->extensions = NULL; + __skb_ext_put(ext); +#ifdef CONFIG_XFRM + } else if (id == SKB_EXT_SEC_PATH && + refcount_read(&ext->refcnt) == 1) { + struct sec_path *sp = skb_ext_get_ptr(ext, SKB_EXT_SEC_PATH); + + skb_ext_put_sp(sp); + sp->len = 0; +#endif + } +} +EXPORT_SYMBOL(__skb_ext_del); + +void __skb_ext_put(struct skb_ext *ext) +{ + /* If this is last clone, nothing can increment + * it after check passes. Avoids one atomic op. + */ + if (refcount_read(&ext->refcnt) == 1) + goto free_now; + + if (!refcount_dec_and_test(&ext->refcnt)) + return; +free_now: +#ifdef CONFIG_XFRM + if (__skb_ext_exist(ext, SKB_EXT_SEC_PATH)) + skb_ext_put_sp(skb_ext_get_ptr(ext, SKB_EXT_SEC_PATH)); +#endif +#ifdef CONFIG_MCTP_FLOWS + if (__skb_ext_exist(ext, SKB_EXT_MCTP)) + skb_ext_put_mctp(skb_ext_get_ptr(ext, SKB_EXT_MCTP)); +#endif + + kmem_cache_free(skbuff_ext_cache, ext); +} +EXPORT_SYMBOL(__skb_ext_put); +#endif /* CONFIG_SKB_EXTENSIONS */ + +/** + * skb_attempt_defer_free - queue skb for remote freeing + * @skb: buffer + * + * Put @skb in a per-cpu list, using the cpu which + * allocated the skb/pages to reduce false sharing + * and memory zone spinlock contention. + */ +void skb_attempt_defer_free(struct sk_buff *skb) +{ + int cpu = skb->alloc_cpu; + struct softnet_data *sd; + unsigned int defer_max; + bool kick; + + if (WARN_ON_ONCE(cpu >= nr_cpu_ids) || + !cpu_online(cpu) || + cpu == raw_smp_processor_id()) { +nodefer: __kfree_skb(skb); + return; + } + + DEBUG_NET_WARN_ON_ONCE(skb_dst(skb)); + DEBUG_NET_WARN_ON_ONCE(skb->destructor); + + sd = &per_cpu(softnet_data, cpu); + defer_max = READ_ONCE(sysctl_skb_defer_max); + if (READ_ONCE(sd->defer_count) >= defer_max) + goto nodefer; + + spin_lock_bh(&sd->defer_lock); + /* Send an IPI every time queue reaches half capacity. */ + kick = sd->defer_count == (defer_max >> 1); + /* Paired with the READ_ONCE() few lines above */ + WRITE_ONCE(sd->defer_count, sd->defer_count + 1); + + skb->next = sd->defer_list; + /* Paired with READ_ONCE() in skb_defer_free_flush() */ + WRITE_ONCE(sd->defer_list, skb); + spin_unlock_bh(&sd->defer_lock); + + /* Make sure to trigger NET_RX_SOFTIRQ on the remote CPU + * if we are unlucky enough (this seems very unlikely). + */ + if (unlikely(kick) && !cmpxchg(&sd->defer_ipi_scheduled, 0, 1)) + smp_call_function_single_async(cpu, &sd->defer_csd); +} + +static void skb_splice_csum_page(struct sk_buff *skb, struct page *page, + size_t offset, size_t len) +{ + const char *kaddr; + __wsum csum; + + kaddr = kmap_local_page(page); + csum = csum_partial(kaddr + offset, len, 0); + kunmap_local(kaddr); + skb->csum = csum_block_add(skb->csum, csum, skb->len); +} + +/** + * skb_splice_from_iter - Splice (or copy) pages to skbuff + * @skb: The buffer to add pages to + * @iter: Iterator representing the pages to be added + * @maxsize: Maximum amount of pages to be added + * @gfp: Allocation flags + * + * This is a common helper function for supporting MSG_SPLICE_PAGES. It + * extracts pages from an iterator and adds them to the socket buffer if + * possible, copying them to fragments if not possible (such as if they're slab + * pages). + * + * Returns the amount of data spliced/copied or -EMSGSIZE if there's + * insufficient space in the buffer to transfer anything. + */ +ssize_t skb_splice_from_iter(struct sk_buff *skb, struct iov_iter *iter, + ssize_t maxsize, gfp_t gfp) +{ + size_t frag_limit = READ_ONCE(sysctl_max_skb_frags); + struct page *pages[8], **ppages = pages; + ssize_t spliced = 0, ret = 0; + unsigned int i; + + while (iter->count > 0) { + ssize_t space, nr, len; + size_t off; + + ret = -EMSGSIZE; + space = frag_limit - skb_shinfo(skb)->nr_frags; + if (space < 0) + break; + + /* We might be able to coalesce without increasing nr_frags */ + nr = clamp_t(size_t, space, 1, ARRAY_SIZE(pages)); + + len = iov_iter_extract_pages(iter, &ppages, maxsize, nr, 0, &off); + if (len <= 0) { + ret = len ?: -EIO; + break; + } + + i = 0; + do { + struct page *page = pages[i++]; + size_t part = min_t(size_t, PAGE_SIZE - off, len); + + ret = -EIO; + if (WARN_ON_ONCE(!sendpage_ok(page))) + goto out; + + ret = skb_append_pagefrags(skb, page, off, part, + frag_limit); + if (ret < 0) { + iov_iter_revert(iter, len); + goto out; + } + + if (skb->ip_summed == CHECKSUM_NONE) + skb_splice_csum_page(skb, page, off, part); + + off = 0; + spliced += part; + maxsize -= part; + len -= part; + } while (len > 0); + + if (maxsize <= 0) + break; + } + +out: + skb_len_add(skb, spliced); + return spliced ?: ret; +} +EXPORT_SYMBOL(skb_splice_from_iter); |