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Commit 716ea3a7 authored by David Howells's avatar David Howells Committed by David S. Miller
Browse files

[NET]: Move generic skbuff stuff from XFRM code to generic code 



Move generic skbuff stuff from XFRM code to generic code so that
AF_RXRPC can use it too.

The kdoc comments I've attached to the functions needs to be checked
by whoever wrote them as I had to make some guesses about the workings
of these functions.

Signed-off-By: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 926554c4

include/linux/skbuff.h

+6 −0
Original line number Diff line number Diff line
@@ -86,6 +86,7 @@ 
 */



struct net_device;

struct scatterlist;



#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)

struct nf_conntrack {
@@ -347,6 +348,11 @@ extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, 
extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,

				       int newheadroom, int newtailroom,

				       gfp_t priority);

extern int	       skb_to_sgvec(struct sk_buff *skb,

				    struct scatterlist *sg, int offset,

				    int len);

extern int	       skb_cow_data(struct sk_buff *skb, int tailbits,

				    struct sk_buff **trailer);

extern int	       skb_pad(struct sk_buff *skb, int pad);

#define dev_kfree_skb(a)	kfree_skb(a)

extern void	      skb_over_panic(struct sk_buff *skb, int len,

include/net/esp.h

+0 −2
Original line number Diff line number Diff line
@@ -40,8 +40,6 @@ struct esp_data 
	} auth;

};



extern int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len);

extern int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);

extern void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);



static inline int esp_mac_digest(struct esp_data *esp, struct sk_buff *skb,

net/core/skbuff.c

+188 −0
Original line number Diff line number Diff line
@@ -55,6 +55,7 @@ 
#include <linux/cache.h>

#include <linux/rtnetlink.h>

#include <linux/init.h>

#include <linux/scatterlist.h>



#include <net/protocol.h>

#include <net/dst.h>
@@ -2002,6 +2003,190 @@ void __init skb_init(void) 
						NULL, NULL);

}



/**

 *	skb_to_sgvec - Fill a scatter-gather list from a socket buffer

 *	@skb: Socket buffer containing the buffers to be mapped

 *	@sg: The scatter-gather list to map into

 *	@offset: The offset into the buffer's contents to start mapping

 *	@len: Length of buffer space to be mapped

 *

 *	Fill the specified scatter-gather list with mappings/pointers into a

 *	region of the buffer space attached to a socket buffer.

 */

int

skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)

{

	int start = skb_headlen(skb);

	int i, copy = start - offset;

	int elt = 0;



	if (copy > 0) {

		if (copy > len)

			copy = len;

		sg[elt].page = virt_to_page(skb->data + offset);

		sg[elt].offset = (unsigned long)(skb->data + offset) % PAGE_SIZE;

		sg[elt].length = copy;

		elt++;

		if ((len -= copy) == 0)

			return elt;

		offset += copy;

	}



	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {

		int end;



		BUG_TRAP(start <= offset + len);



		end = start + skb_shinfo(skb)->frags[i].size;

		if ((copy = end - offset) > 0) {

			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];



			if (copy > len)

				copy = len;

			sg[elt].page = frag->page;

			sg[elt].offset = frag->page_offset+offset-start;

			sg[elt].length = copy;

			elt++;

			if (!(len -= copy))

				return elt;

			offset += copy;

		}

		start = end;

	}



	if (skb_shinfo(skb)->frag_list) {

		struct sk_buff *list = skb_shinfo(skb)->frag_list;



		for (; list; list = list->next) {

			int end;



			BUG_TRAP(start <= offset + len);



			end = start + list->len;

			if ((copy = end - offset) > 0) {

				if (copy > len)

					copy = len;

				elt += skb_to_sgvec(list, sg+elt, offset - start, copy);

				if ((len -= copy) == 0)

					return elt;

				offset += copy;

			}

			start = end;

		}

	}

	BUG_ON(len);

	return elt;

}



/**

 *	skb_cow_data - Check that a socket buffer's data buffers are writable

 *	@skb: The socket buffer to check.

 *	@tailbits: Amount of trailing space to be added

 *	@trailer: Returned pointer to the skb where the @tailbits space begins

 *

 *	Make sure that the data buffers attached to a socket buffer are

 *	writable. If they are not, private copies are made of the data buffers

 *	and the socket buffer is set to use these instead.

 *

 *	If @tailbits is given, make sure that there is space to write @tailbits

 *	bytes of data beyond current end of socket buffer.  @trailer will be

 *	set to point to the skb in which this space begins.

 *

 *	The number of scatterlist elements required to completely map the

 *	COW'd and extended socket buffer will be returned.

 */

int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)

{

	int copyflag;

	int elt;

	struct sk_buff *skb1, **skb_p;



	/* If skb is cloned or its head is paged, reallocate

	 * head pulling out all the pages (pages are considered not writable

	 * at the moment even if they are anonymous).

	 */

	if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&

	    __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)

		return -ENOMEM;



	/* Easy case. Most of packets will go this way. */

	if (!skb_shinfo(skb)->frag_list) {

		/* 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_shinfo(skb1)->frag_list ||

			    skb_tailroom(skb1) < tailbits)

				ntail = tailbits + 128;

		}



		if (copyflag ||

		    skb_cloned(skb1) ||

		    ntail ||

		    skb_shinfo(skb1)->nr_frags ||

		    skb_shinfo(skb1)->frag_list) {

			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(___pskb_trim);

EXPORT_SYMBOL(__kfree_skb);

EXPORT_SYMBOL(kfree_skb);
@@ -2036,3 +2221,6 @@ EXPORT_SYMBOL(skb_seq_read); 
EXPORT_SYMBOL(skb_abort_seq_read);

EXPORT_SYMBOL(skb_find_text);

EXPORT_SYMBOL(skb_append_datato_frags);



EXPORT_SYMBOL_GPL(skb_to_sgvec);

EXPORT_SYMBOL_GPL(skb_cow_data);

net/xfrm/xfrm_algo.c

+0 −169
Original line number Diff line number Diff line
@@ -612,175 +612,6 @@ EXPORT_SYMBOL_GPL(skb_icv_walk); 


#if defined(CONFIG_INET_ESP) || defined(CONFIG_INET_ESP_MODULE) || defined(CONFIG_INET6_ESP) || defined(CONFIG_INET6_ESP_MODULE)



/* Looking generic it is not used in another places. */



int

skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)

{

	int start = skb_headlen(skb);

	int i, copy = start - offset;

	int elt = 0;



	if (copy > 0) {

		if (copy > len)

			copy = len;

		sg[elt].page = virt_to_page(skb->data + offset);

		sg[elt].offset = (unsigned long)(skb->data + offset) % PAGE_SIZE;

		sg[elt].length = copy;

		elt++;

		if ((len -= copy) == 0)

			return elt;

		offset += copy;

	}



	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {

		int end;



		BUG_TRAP(start <= offset + len);



		end = start + skb_shinfo(skb)->frags[i].size;

		if ((copy = end - offset) > 0) {

			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];



			if (copy > len)

				copy = len;

			sg[elt].page = frag->page;

			sg[elt].offset = frag->page_offset+offset-start;

			sg[elt].length = copy;

			elt++;

			if (!(len -= copy))

				return elt;

			offset += copy;

		}

		start = end;

	}



	if (skb_shinfo(skb)->frag_list) {

		struct sk_buff *list = skb_shinfo(skb)->frag_list;



		for (; list; list = list->next) {

			int end;



			BUG_TRAP(start <= offset + len);



			end = start + list->len;

			if ((copy = end - offset) > 0) {

				if (copy > len)

					copy = len;

				elt += skb_to_sgvec(list, sg+elt, offset - start, copy);

				if ((len -= copy) == 0)

					return elt;

				offset += copy;

			}

			start = end;

		}

	}

	BUG_ON(len);

	return elt;

}

EXPORT_SYMBOL_GPL(skb_to_sgvec);



/* Check that skb data bits are writable. If they are not, copy data

 * to newly created private area. If "tailbits" is given, make sure that

 * tailbits bytes beyond current end of skb are writable.

 *

 * Returns amount of elements of scatterlist to load for subsequent

 * transformations and pointer to writable trailer skb.

 */



int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)

{

	int copyflag;

	int elt;

	struct sk_buff *skb1, **skb_p;



	/* If skb is cloned or its head is paged, reallocate

	 * head pulling out all the pages (pages are considered not writable

	 * at the moment even if they are anonymous).

	 */

	if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&

	    __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)

		return -ENOMEM;



	/* Easy case. Most of packets will go this way. */

	if (!skb_shinfo(skb)->frag_list) {

		/* 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_shinfo(skb1)->frag_list ||

			    skb_tailroom(skb1) < tailbits)

				ntail = tailbits + 128;

		}



		if (copyflag ||

		    skb_cloned(skb1) ||

		    ntail ||

		    skb_shinfo(skb1)->nr_frags ||

		    skb_shinfo(skb1)->frag_list) {

			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);



void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len)

{

	if (tail != skb) {