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net: add copy from skb_seq_state to buffer function

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

Signed-off-by: Christian Hopps <chopps@labn.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This commit is contained in:
Christian Hopps 2024-08-15 13:21:14 -04:00 committed by Steffen Klassert
parent 9b49f55838
commit 6ad8bc92a4
2 changed files with 36 additions and 0 deletions
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1
include/linux/skbuff.h
View File

@ -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);

35
net/core/skbuff.c
View File

@ -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,