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Diffstat (limited to 'br-nf-bds/linux/include/linux/skbuff.h')
| -rw-r--r-- | br-nf-bds/linux/include/linux/skbuff.h | 1152 |
1 files changed, 1152 insertions, 0 deletions
diff --git a/br-nf-bds/linux/include/linux/skbuff.h b/br-nf-bds/linux/include/linux/skbuff.h new file mode 100644 index 0000000..257b586 --- /dev/null +++ b/br-nf-bds/linux/include/linux/skbuff.h @@ -0,0 +1,1152 @@ +/* + * Definitions for the 'struct sk_buff' memory handlers. + * + * Authors: + * Alan Cox, <gw4pts@gw4pts.ampr.org> + * Florian La Roche, <rzsfl@rz.uni-sb.de> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#ifndef _LINUX_SKBUFF_H +#define _LINUX_SKBUFF_H + +#include <linux/config.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/time.h> +#include <linux/cache.h> + +#include <asm/atomic.h> +#include <asm/types.h> +#include <linux/spinlock.h> +#include <linux/mm.h> +#include <linux/highmem.h> + +#define HAVE_ALLOC_SKB /* For the drivers to know */ +#define HAVE_ALIGNABLE_SKB /* Ditto 8) */ +#define SLAB_SKB /* Slabified skbuffs */ + +#define CHECKSUM_NONE 0 +#define CHECKSUM_HW 1 +#define CHECKSUM_UNNECESSARY 2 + +#define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES-1)) & ~(SMP_CACHE_BYTES-1)) +#define SKB_MAX_ORDER(X,ORDER) (((PAGE_SIZE<<(ORDER)) - (X) - sizeof(struct skb_shared_info))&~(SMP_CACHE_BYTES-1)) +#define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X),0)) +#define SKB_MAX_ALLOC (SKB_MAX_ORDER(0,2)) + +/* A. Checksumming of received packets by device. + * + * NONE: device failed to checksum this packet. + * skb->csum is undefined. + * + * UNNECESSARY: device parsed packet and wouldbe verified checksum. + * skb->csum is undefined. + * It is bad option, but, unfortunately, many of vendors do this. + * Apparently with secret goal to sell you new device, when you + * will add new protocol to your host. F.e. IPv6. 8) + * + * HW: the most generic way. Device supplied checksum of _all_ + * the packet as seen by netif_rx in skb->csum. + * NOTE: Even if device supports only some protocols, but + * is able to produce some skb->csum, it MUST use HW, + * not UNNECESSARY. + * + * B. Checksumming on output. + * + * NONE: skb is checksummed by protocol or csum is not required. + * + * HW: device is required to csum packet as seen by hard_start_xmit + * from skb->h.raw to the end and to record the checksum + * at skb->h.raw+skb->csum. + * + * Device must show its capabilities in dev->features, set + * at device setup time. + * NETIF_F_HW_CSUM - it is clever device, it is able to checksum + * everything. + * NETIF_F_NO_CSUM - loopback or reliable single hop media. + * NETIF_F_IP_CSUM - device is dumb. It is able to csum only + * TCP/UDP over IPv4. Sigh. Vendors like this + * way by an unknown reason. Though, see comment above + * about CHECKSUM_UNNECESSARY. 8) + * + * Any questions? No questions, good. --ANK + */ + +#ifdef __i386__ +#define NET_CALLER(arg) (*(((void**)&arg)-1)) +#else +#define NET_CALLER(arg) __builtin_return_address(0) +#endif + +#ifdef CONFIG_NETFILTER +struct nf_conntrack { + atomic_t use; + void (*destroy)(struct nf_conntrack *); +}; + +struct nf_ct_info { + struct nf_conntrack *master; +}; +#endif + +struct sk_buff_head { + /* These two members must be first. */ + struct sk_buff * next; + struct sk_buff * prev; + + __u32 qlen; + spinlock_t lock; +}; + +struct sk_buff; + +#define MAX_SKB_FRAGS 6 + +typedef struct skb_frag_struct skb_frag_t; + +struct skb_frag_struct +{ + struct page *page; + __u16 page_offset; + __u16 size; +}; + +/* This data is invariant across clones and lives at + * the end of the header data, ie. at skb->end. + */ +struct skb_shared_info { + atomic_t dataref; + unsigned int nr_frags; + struct sk_buff *frag_list; + skb_frag_t frags[MAX_SKB_FRAGS]; +}; + +struct sk_buff { + /* These two members must be first. */ + struct sk_buff * next; /* Next buffer in list */ + struct sk_buff * prev; /* Previous buffer in list */ + + struct sk_buff_head * list; /* List we are on */ + struct sock *sk; /* Socket we are owned by */ + struct timeval stamp; /* Time we arrived */ + struct net_device *dev; /* Device we arrived on/are leaving by */ + struct net_device *physindev; /* Physical device we arrived on */ + struct net_device *physoutdev; /* Physical device we will leave by */ + + /* Transport layer header */ + union + { + struct tcphdr *th; + struct udphdr *uh; + struct icmphdr *icmph; + struct igmphdr *igmph; + struct iphdr *ipiph; + struct spxhdr *spxh; + unsigned char *raw; + } h; + + /* Network layer header */ + union + { + struct iphdr *iph; + struct ipv6hdr *ipv6h; + struct arphdr *arph; + struct ipxhdr *ipxh; + unsigned char *raw; + } nh; + + /* Link layer header */ + union + { + struct ethhdr *ethernet; + unsigned char *raw; + } mac; + + struct dst_entry *dst; + + /* + * This is the control buffer. It is free to use for every + * layer. Please put your private variables there. If you + * want to keep them across layers you have to do a skb_clone() + * first. This is owned by whoever has the skb queued ATM. + */ + char cb[48]; + + unsigned int len; /* Length of actual data */ + unsigned int data_len; + unsigned int csum; /* Checksum */ + unsigned char __unused, /* Dead field, may be reused */ + cloned, /* head may be cloned (check refcnt to be sure). */ + pkt_type, /* Packet class */ + ip_summed; /* Driver fed us an IP checksum */ + __u32 priority; /* Packet queueing priority */ + atomic_t users; /* User count - see datagram.c,tcp.c */ + unsigned short protocol; /* Packet protocol from driver. */ + unsigned short security; /* Security level of packet */ + unsigned int truesize; /* Buffer size */ + + unsigned char *head; /* Head of buffer */ + unsigned char *data; /* Data head pointer */ + unsigned char *tail; /* Tail pointer */ + unsigned char *end; /* End pointer */ + + void (*destructor)(struct sk_buff *); /* Destruct function */ +#ifdef CONFIG_NETFILTER + /* Can be used for communication between hooks. */ + unsigned long nfmark; + /* Cache info */ + __u32 nfcache; + /* Associated connection, if any */ + struct nf_ct_info *nfct; +#ifdef CONFIG_NETFILTER_DEBUG + unsigned int nf_debug; +#endif +#endif /*CONFIG_NETFILTER*/ + +#if defined(CONFIG_HIPPI) + union{ + __u32 ifield; + } private; +#endif + +#ifdef CONFIG_NET_SCHED + __u32 tc_index; /* traffic control index */ +#endif +}; + +#define SK_WMEM_MAX 65535 +#define SK_RMEM_MAX 65535 + +#ifdef __KERNEL__ +/* + * Handling routines are only of interest to the kernel + */ +#include <linux/slab.h> + +#include <asm/system.h> + +extern void __kfree_skb(struct sk_buff *skb); +extern struct sk_buff * alloc_skb(unsigned int size, int priority); +extern void kfree_skbmem(struct sk_buff *skb); +extern struct sk_buff * skb_clone(struct sk_buff *skb, int priority); +extern struct sk_buff * skb_copy(const struct sk_buff *skb, int priority); +extern struct sk_buff * pskb_copy(struct sk_buff *skb, int gfp_mask); +extern int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, int gfp_mask); +extern struct sk_buff * skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom); +extern struct sk_buff * skb_copy_expand(const struct sk_buff *skb, + int newheadroom, + int newtailroom, + int priority); +#define dev_kfree_skb(a) kfree_skb(a) +extern void skb_over_panic(struct sk_buff *skb, int len, void *here); +extern void skb_under_panic(struct sk_buff *skb, int len, void *here); + +/* Internal */ +#define skb_shinfo(SKB) ((struct skb_shared_info *)((SKB)->end)) + +/** + * skb_queue_empty - check if a queue is empty + * @list: queue head + * + * Returns true if the queue is empty, false otherwise. + */ + +static inline int skb_queue_empty(struct sk_buff_head *list) +{ + return (list->next == (struct sk_buff *) list); +} + +/** + * skb_get - reference buffer + * @skb: buffer to reference + * + * Makes another reference to a socket buffer and returns a pointer + * to the buffer. + */ + +static inline struct sk_buff *skb_get(struct sk_buff *skb) +{ + atomic_inc(&skb->users); + return skb; +} + +/* + * If users==1, we are the only owner and are can avoid redundant + * atomic change. + */ + +/** + * kfree_skb - free an sk_buff + * @skb: buffer to free + * + * Drop a reference to the buffer and free it if the usage count has + * hit zero. + */ + +static inline void kfree_skb(struct sk_buff *skb) +{ + if (atomic_read(&skb->users) == 1 || atomic_dec_and_test(&skb->users)) + __kfree_skb(skb); +} + +/* Use this if you didn't touch the skb state [for fast switching] */ +static inline void kfree_skb_fast(struct sk_buff *skb) +{ + if (atomic_read(&skb->users) == 1 || atomic_dec_and_test(&skb->users)) + kfree_skbmem(skb); +} + +/** + * skb_cloned - is the buffer a clone + * @skb: buffer to check + * + * Returns true if the buffer was generated with skb_clone() and is + * one of multiple shared copies of the buffer. Cloned buffers are + * shared data so must not be written to under normal circumstances. + */ + +static inline int skb_cloned(struct sk_buff *skb) +{ + return skb->cloned && atomic_read(&skb_shinfo(skb)->dataref) != 1; +} + +/** + * skb_shared - is the buffer shared + * @skb: buffer to check + * + * Returns true if more than one person has a reference to this + * buffer. + */ + +static inline int skb_shared(struct sk_buff *skb) +{ + return (atomic_read(&skb->users) != 1); +} + +/** + * skb_share_check - check if buffer is shared and if so clone it + * @skb: buffer to check + * @pri: priority for memory allocation + * + * If the buffer is shared the buffer is cloned and the old copy + * drops a reference. A new clone with a single reference is returned. + * If the buffer is not shared the original buffer is returned. When + * being called from interrupt status or with spinlocks held pri must + * be GFP_ATOMIC. + * + * NULL is returned on a memory allocation failure. + */ + +static inline struct sk_buff *skb_share_check(struct sk_buff *skb, int pri) +{ + if (skb_shared(skb)) { + struct sk_buff *nskb; + nskb = skb_clone(skb, pri); + kfree_skb(skb); + return nskb; + } + return skb; +} + + +/* + * Copy shared buffers into a new sk_buff. We effectively do COW on + * packets to handle cases where we have a local reader and forward + * and a couple of other messy ones. The normal one is tcpdumping + * a packet thats being forwarded. + */ + +/** + * skb_unshare - make a copy of a shared buffer + * @skb: buffer to check + * @pri: priority for memory allocation + * + * If the socket buffer is a clone then this function creates a new + * copy of the data, drops a reference count on the old copy and returns + * the new copy with the reference count at 1. If the buffer is not a clone + * the original buffer is returned. When called with a spinlock held or + * from interrupt state @pri must be %GFP_ATOMIC + * + * %NULL is returned on a memory allocation failure. + */ + +static inline struct sk_buff *skb_unshare(struct sk_buff *skb, int pri) +{ + struct sk_buff *nskb; + if(!skb_cloned(skb)) + return skb; + nskb=skb_copy(skb, pri); + kfree_skb(skb); /* Free our shared copy */ + return nskb; +} + +/** + * skb_peek + * @list_: list to peek at + * + * Peek an &sk_buff. Unlike most other operations you _MUST_ + * be careful with this one. A peek leaves the buffer on the + * list and someone else may run off with it. You must hold + * the appropriate locks or have a private queue to do this. + * + * Returns %NULL for an empty list or a pointer to the head element. + * The reference count is not incremented and the reference is therefore + * volatile. Use with caution. + */ + +static inline struct sk_buff *skb_peek(struct sk_buff_head *list_) +{ + struct sk_buff *list = ((struct sk_buff *)list_)->next; + if (list == (struct sk_buff *)list_) + list = NULL; + return list; +} + +/** + * skb_peek_tail + * @list_: list to peek at + * + * Peek an &sk_buff. Unlike most other operations you _MUST_ + * be careful with this one. A peek leaves the buffer on the + * list and someone else may run off with it. You must hold + * the appropriate locks or have a private queue to do this. + * + * Returns %NULL for an empty list or a pointer to the tail element. + * The reference count is not incremented and the reference is therefore + * volatile. Use with caution. + */ + +static inline struct sk_buff *skb_peek_tail(struct sk_buff_head *list_) +{ + struct sk_buff *list = ((struct sk_buff *)list_)->prev; + if (list == (struct sk_buff *)list_) + list = NULL; + return list; +} + +/** + * skb_queue_len - get queue length + * @list_: list to measure + * + * Return the length of an &sk_buff queue. + */ + +static inline __u32 skb_queue_len(struct sk_buff_head *list_) +{ + return(list_->qlen); +} + +static inline void skb_queue_head_init(struct sk_buff_head *list) +{ + spin_lock_init(&list->lock); + list->prev = (struct sk_buff *)list; + list->next = (struct sk_buff *)list; + list->qlen = 0; +} + +/* + * Insert an sk_buff at the start of a list. + * + * The "__skb_xxxx()" functions are the non-atomic ones that + * can only be called with interrupts disabled. + */ + +/** + * __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 a list. This function takes no locks + * and you must therefore hold required locks before calling it. + * + * A buffer cannot be placed on two lists at the same time. + */ + +static inline void __skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk) +{ + struct sk_buff *prev, *next; + + newsk->list = list; + list->qlen++; + prev = (struct sk_buff *)list; + next = prev->next; + newsk->next = next; + newsk->prev = prev; + next->prev = newsk; + prev->next = newsk; +} + + +/** + * 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. + */ + +static inline void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk) +{ + unsigned long flags; + + spin_lock_irqsave(&list->lock, flags); + __skb_queue_head(list, newsk); + spin_unlock_irqrestore(&list->lock, flags); +} + +/** + * __skb_queue_tail - queue a buffer at the list tail + * @list: list to use + * @newsk: buffer to queue + * + * Queue a buffer at the end of a list. This function takes no locks + * and you must therefore hold required locks before calling it. + * + * A buffer cannot be placed on two lists at the same time. + */ + + +static inline void __skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk) +{ + struct sk_buff *prev, *next; + + newsk->list = list; + list->qlen++; + next = (struct sk_buff *)list; + prev = next->prev; + newsk->next = next; + newsk->prev = prev; + next->prev = newsk; + prev->next = newsk; +} + +/** + * 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. + */ + +static inline void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk) +{ + unsigned long flags; + + spin_lock_irqsave(&list->lock, flags); + __skb_queue_tail(list, newsk); + spin_unlock_irqrestore(&list->lock, flags); +} + +/** + * __skb_dequeue - remove from the head of the queue + * @list: list to dequeue from + * + * Remove the head of the list. This function does not take any locks + * so must be used with appropriate locks held only. The head item is + * returned or %NULL if the list is empty. + */ + +static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list) +{ + struct sk_buff *next, *prev, *result; + + prev = (struct sk_buff *) list; + next = prev->next; + result = NULL; + if (next != prev) { + result = next; + next = next->next; + list->qlen--; + next->prev = prev; + prev->next = next; + result->next = NULL; + result->prev = NULL; + result->list = NULL; + } + return result; +} + +/** + * 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. + */ + +static inline struct sk_buff *skb_dequeue(struct sk_buff_head *list) +{ + long flags; + struct sk_buff *result; + + spin_lock_irqsave(&list->lock, flags); + result = __skb_dequeue(list); + spin_unlock_irqrestore(&list->lock, flags); + return result; +} + +/* + * Insert a packet on a list. + */ + +static inline void __skb_insert(struct sk_buff *newsk, + struct sk_buff * prev, struct sk_buff *next, + struct sk_buff_head * list) +{ + newsk->next = next; + newsk->prev = prev; + next->prev = newsk; + prev->next = newsk; + newsk->list = list; + list->qlen++; +} + +/** + * skb_insert - insert a buffer + * @old: buffer to insert before + * @newsk: buffer to insert + * + * Place a packet before a given packet in a list. The list locks are taken + * and this function is atomic with respect to other list locked calls + * A buffer cannot be placed on two lists at the same time. + */ + +static inline void skb_insert(struct sk_buff *old, struct sk_buff *newsk) +{ + unsigned long flags; + + spin_lock_irqsave(&old->list->lock, flags); + __skb_insert(newsk, old->prev, old, old->list); + spin_unlock_irqrestore(&old->list->lock, flags); +} + +/* + * Place a packet after a given packet in a list. + */ + +static inline void __skb_append(struct sk_buff *old, struct sk_buff *newsk) +{ + __skb_insert(newsk, old, old->next, old->list); +} + +/** + * skb_append - append a buffer + * @old: buffer to insert after + * @newsk: buffer to insert + * + * Place a packet after a given packet in a list. The list locks are taken + * and this function is atomic with respect to other list locked calls. + * A buffer cannot be placed on two lists at the same time. + */ + + +static inline void skb_append(struct sk_buff *old, struct sk_buff *newsk) +{ + unsigned long flags; + + spin_lock_irqsave(&old->list->lock, flags); + __skb_append(old, newsk); + spin_unlock_irqrestore(&old->list->lock, flags); +} + +/* + * remove sk_buff from list. _Must_ be called atomically, and with + * the list known.. + */ + +static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list) +{ + struct sk_buff * next, * prev; + + list->qlen--; + next = skb->next; + prev = skb->prev; + skb->next = NULL; + skb->prev = NULL; + skb->list = NULL; + next->prev = prev; + prev->next = next; +} + +/** + * skb_unlink - remove a buffer from a list + * @skb: buffer to remove + * + * Place a packet after a given packet in a list. The list locks are taken + * and this function is atomic with respect to other list locked calls + * + * Works even without knowing the list it is sitting on, which can be + * handy at times. It also means that THE LIST MUST EXIST when you + * unlink. Thus a list must have its contents unlinked before it is + * destroyed. + */ + +static inline void skb_unlink(struct sk_buff *skb) +{ + struct sk_buff_head *list = skb->list; + + if(list) { + unsigned long flags; + + spin_lock_irqsave(&list->lock, flags); + if(skb->list == list) + __skb_unlink(skb, skb->list); + spin_unlock_irqrestore(&list->lock, flags); + } +} + +/* XXX: more streamlined implementation */ + +/** + * __skb_dequeue_tail - remove from the tail of the queue + * @list: list to dequeue from + * + * Remove the tail of the list. This function does not take any locks + * so must be used with appropriate locks held only. The tail item is + * returned or %NULL if the list is empty. + */ + +static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list) +{ + struct sk_buff *skb = skb_peek_tail(list); + if (skb) + __skb_unlink(skb, list); + return skb; +} + +/** + * 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 tail item is + * returned or %NULL if the list is empty. + */ + +static inline struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list) +{ + 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; +} + +static inline int skb_is_nonlinear(const struct sk_buff *skb) +{ + return skb->data_len; +} + +static inline int skb_headlen(const struct sk_buff *skb) +{ + return skb->len - skb->data_len; +} + +#define SKB_PAGE_ASSERT(skb) do { if (skb_shinfo(skb)->nr_frags) BUG(); } while (0) +#define SKB_FRAG_ASSERT(skb) do { if (skb_shinfo(skb)->frag_list) BUG(); } while (0) +#define SKB_LINEAR_ASSERT(skb) do { if (skb_is_nonlinear(skb)) BUG(); } while (0) + +/* + * Add data to an sk_buff + */ + +static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len) +{ + unsigned char *tmp=skb->tail; + SKB_LINEAR_ASSERT(skb); + skb->tail+=len; + skb->len+=len; + return tmp; +} + +/** + * 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. + */ + +static inline unsigned char *skb_put(struct sk_buff *skb, unsigned int len) +{ + unsigned char *tmp=skb->tail; + SKB_LINEAR_ASSERT(skb); + skb->tail+=len; + skb->len+=len; + if(skb->tail>skb->end) { + skb_over_panic(skb, len, current_text_addr()); + } + return tmp; +} + +static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len) +{ + skb->data-=len; + skb->len+=len; + return skb->data; +} + +/** + * 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. + */ + +static inline unsigned char *skb_push(struct sk_buff *skb, unsigned int len) +{ + skb->data-=len; + skb->len+=len; + if(skb->data<skb->head) { + skb_under_panic(skb, len, current_text_addr()); + } + return skb->data; +} + +static inline char *__skb_pull(struct sk_buff *skb, unsigned int len) +{ + skb->len-=len; + if (skb->len < skb->data_len) + BUG(); + return skb->data+=len; +} + +/** + * 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. + */ + +static inline unsigned char * skb_pull(struct sk_buff *skb, unsigned int len) +{ + if (len > skb->len) + return NULL; + return __skb_pull(skb,len); +} + +extern unsigned char * __pskb_pull_tail(struct sk_buff *skb, int delta); + +static inline char *__pskb_pull(struct sk_buff *skb, unsigned int len) +{ + if (len > skb_headlen(skb) && + __pskb_pull_tail(skb, len-skb_headlen(skb)) == NULL) + return NULL; + skb->len -= len; + return skb->data += len; +} + +static inline unsigned char * pskb_pull(struct sk_buff *skb, unsigned int len) +{ + if (len > skb->len) + return NULL; + return __pskb_pull(skb,len); +} + +static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len) +{ + if (len <= skb_headlen(skb)) + return 1; + if (len > skb->len) + return 0; + return (__pskb_pull_tail(skb, len-skb_headlen(skb)) != NULL); +} + +/** + * skb_headroom - bytes at buffer head + * @skb: buffer to check + * + * Return the number of bytes of free space at the head of an &sk_buff. + */ + +static inline int skb_headroom(const struct sk_buff *skb) +{ + return skb->data-skb->head; +} + +/** + * skb_tailroom - bytes at buffer end + * @skb: buffer to check + * + * Return the number of bytes of free space at the tail of an sk_buff + */ + +static inline int skb_tailroom(const struct sk_buff *skb) +{ + return skb_is_nonlinear(skb) ? 0 : skb->end-skb->tail; +} + +/** + * skb_reserve - adjust headroom + * @skb: buffer to alter + * @len: bytes to move + * + * Increase the headroom of an empty &sk_buff by reducing the tail + * room. This is only allowed for an empty buffer. + */ + +static inline void skb_reserve(struct sk_buff *skb, unsigned int len) +{ + skb->data+=len; + skb->tail+=len; +} + +extern int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc); + +static inline void __skb_trim(struct sk_buff *skb, unsigned int len) +{ + if (!skb->data_len) { + skb->len = len; + skb->tail = skb->data+len; + } else { + ___pskb_trim(skb, len, 0); + } +} + +/** + * 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. + */ + +static inline void skb_trim(struct sk_buff *skb, unsigned int len) +{ + if (skb->len > len) { + __skb_trim(skb, len); + } +} + + +static inline int __pskb_trim(struct sk_buff *skb, unsigned int len) +{ + if (!skb->data_len) { + skb->len = len; + skb->tail = skb->data+len; + return 0; + } else { + return ___pskb_trim(skb, len, 1); + } +} + +static inline int pskb_trim(struct sk_buff *skb, unsigned int len) +{ + if (len < skb->len) + return __pskb_trim(skb, len); + return 0; +} + +/** + * skb_orphan - orphan a buffer + * @skb: buffer to orphan + * + * If a buffer currently has an owner then we call the owner's + * destructor function and make the @skb unowned. The buffer continues + * to exist but is no longer charged to its former owner. + */ + + +static inline void skb_orphan(struct sk_buff *skb) +{ + if (skb->destructor) + skb->destructor(skb); + skb->destructor = NULL; + skb->sk = NULL; +} + +/** + * skb_purge - empty a list + * @list: list to empty + * + * Delete all buffers on an &sk_buff list. Each buffer is removed from + * the list and one reference dropped. This function takes the list + * lock and is atomic with respect to other list locking functions. + */ + + +static inline void skb_queue_purge(struct sk_buff_head *list) +{ + struct sk_buff *skb; + while ((skb=skb_dequeue(list))!=NULL) + kfree_skb(skb); +} + +/** + * __skb_purge - empty a list + * @list: list to empty + * + * Delete all buffers on an &sk_buff list. Each buffer is removed from + * the list and one reference dropped. This function does not take the + * list lock and the caller must hold the relevant locks to use it. + */ + + +static inline void __skb_queue_purge(struct sk_buff_head *list) +{ + struct sk_buff *skb; + while ((skb=__skb_dequeue(list))!=NULL) + kfree_skb(skb); +} + +/** + * __dev_alloc_skb - allocate an skbuff for sending + * @length: length to allocate + * @gfp_mask: get_free_pages mask, passed to alloc_skb + * + * Allocate a new &sk_buff and assign it a usage count of one. The + * buffer has unspecified headroom built in. Users should allocate + * the headroom they think they need without accounting for the + * built in space. The built in space is used for optimisations. + * + * %NULL is returned in there is no free memory. + */ + +static inline struct sk_buff *__dev_alloc_skb(unsigned int length, + int gfp_mask) +{ + struct sk_buff *skb; + + skb = alloc_skb(length+16, gfp_mask); + if (skb) + skb_reserve(skb,16); + return skb; +} + +/** + * dev_alloc_skb - allocate an skbuff for sending + * @length: length to allocate + * + * Allocate a new &sk_buff and assign it a usage count of one. The + * buffer has unspecified headroom built in. Users should allocate + * the headroom they think they need without accounting for the + * built in space. The built in space is used for optimisations. + * + * %NULL is returned in there is no free memory. Although this function + * allocates memory it can be called from an interrupt. + */ + +static inline struct sk_buff *dev_alloc_skb(unsigned int length) +{ + return __dev_alloc_skb(length, GFP_ATOMIC); +} + +/** + * skb_cow - copy header of skb when it is required + * @skb: buffer to cow + * @headroom: needed headroom + * + * If the skb passed lacks sufficient headroom or its data part + * is shared, data is reallocated. If reallocation fails, an error + * is returned and original skb is not changed. + * + * The result is skb with writable area skb->head...skb->tail + * and at least @headroom of space at head. + */ + +static inline int +skb_cow(struct sk_buff *skb, unsigned int headroom) +{ + int delta = (headroom > 16 ? headroom : 16) - skb_headroom(skb); + + if (delta < 0) + delta = 0; + + if (delta || skb_cloned(skb)) + return pskb_expand_head(skb, (delta+15)&~15, 0, GFP_ATOMIC); + return 0; +} + +/** + * skb_linearize - convert paged skb to linear one + * @skb: buffer to linarize + * @gfp: allocation mode + * + * If there is no free memory -ENOMEM is returned, otherwise zero + * is returned and the old skb data released. */ +int skb_linearize(struct sk_buff *skb, int gfp); + +static inline void *kmap_skb_frag(const skb_frag_t *frag) +{ +#ifdef CONFIG_HIGHMEM + if (in_irq()) + BUG(); + + local_bh_disable(); +#endif + return kmap_atomic(frag->page, KM_SKB_DATA_SOFTIRQ); +} + +static inline void kunmap_skb_frag(void *vaddr) +{ + kunmap_atomic(vaddr, KM_SKB_DATA_SOFTIRQ); +#ifdef CONFIG_HIGHMEM + local_bh_enable(); +#endif +} + +#define skb_queue_walk(queue, skb) \ + for (skb = (queue)->next; \ + (skb != (struct sk_buff *)(queue)); \ + skb=skb->next) + + +extern struct sk_buff * skb_recv_datagram(struct sock *sk,unsigned flags,int noblock, int *err); +extern unsigned int datagram_poll(struct file *file, struct socket *sock, struct poll_table_struct *wait); +extern int skb_copy_datagram(const struct sk_buff *from, int offset, char *to,int size); +extern int skb_copy_datagram_iovec(const struct sk_buff *from, int offset, struct iovec *to,int size); +extern int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset, u8 *to, int len, unsigned int *csump); +extern int skb_copy_and_csum_datagram_iovec(const struct sk_buff *skb, int hlen, struct iovec *iov); +extern void skb_free_datagram(struct sock * sk, struct sk_buff *skb); + +extern unsigned int skb_checksum(const struct sk_buff *skb, int offset, int len, unsigned int csum); +extern int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len); +extern unsigned int skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to, int len, unsigned int csum); +extern void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to); + +extern void skb_init(void); +extern void skb_add_mtu(int mtu); + +#ifdef CONFIG_NETFILTER +static inline void +nf_conntrack_put(struct nf_ct_info *nfct) +{ + if (nfct && atomic_dec_and_test(&nfct->master->use)) + nfct->master->destroy(nfct->master); +} +static inline void +nf_conntrack_get(struct nf_ct_info *nfct) +{ + if (nfct) + atomic_inc(&nfct->master->use); +} +#endif + +#endif /* __KERNEL__ */ +#endif /* _LINUX_SKBUFF_H */ |