Commit 6ad8bc92 authored by Christian Hopps's avatar Christian Hopps Committed by Steffen Klassert
Browse files

net: add copy from skb_seq_state to buffer function 



Add an skb helper function to copy a range of bytes from within
an existing skb_seq_state.

Signed-off-by: default avatarChristian Hopps <chopps@labn.net>
Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
parent 9b49f558

include/linux/skbuff.h

+1 −0
Original line number Diff line number Diff line
@@ -1433,6 +1433,7 @@ void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from, 
unsigned int skb_seq_read(unsigned int consumed, const u8 **data,

			  struct skb_seq_state *st);

void skb_abort_seq_read(struct skb_seq_state *st);

int skb_copy_seq_read(struct skb_seq_state *st, int offset, void *to, int len);



unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,

			   unsigned int to, struct ts_config *config);

net/core/skbuff.c

+35 −0
Original line number Diff line number Diff line
@@ -4409,6 +4409,41 @@ void skb_abort_seq_read(struct skb_seq_state *st) 
}

EXPORT_SYMBOL(skb_abort_seq_read);



/**

 * skb_copy_seq_read() - copy from a skb_seq_state to a buffer

 * @st: source skb_seq_state

 * @offset: offset in source

 * @to: destination buffer

 * @len: number of bytes to copy

 *

 * Copy @len bytes from @offset bytes into the source @st to the destination

 * buffer @to. `offset` should increase (or be unchanged) with each subsequent

 * call to this function. If offset needs to decrease from the previous use `st`

 * should be reset first.

 *

 * Return: 0 on success or -EINVAL if the copy ended early

 */

int skb_copy_seq_read(struct skb_seq_state *st, int offset, void *to, int len)

{

	const u8 *data;

	u32 sqlen;



	for (;;) {

		sqlen = skb_seq_read(offset, &data, st);

		if (sqlen == 0)

			return -EINVAL;

		if (sqlen >= len) {

			memcpy(to, data, len);

			return 0;

		}

		memcpy(to, data, sqlen);

		to += sqlen;

		offset += sqlen;

		len -= sqlen;

	}

}

EXPORT_SYMBOL(skb_copy_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,