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| author | Christian Hopps <chopps@labn.net> | 2024-08-15 13:21:14 -0400 |
|---|---|---|
| committer | Steffen Klassert <steffen.klassert@secunet.com> | 2024-08-20 08:11:48 +0200 |
| commit | 6ad8bc92a47702f0b5d0b96b680199910b89f688 (patch) | |
| tree | a2713b111e104b02d0bcaea18b71d9255514be5a | |
| parent | 9b49f55838b1f42b2624216ce494f0536669e8f0 (diff) | |
| download | lwn-6ad8bc92a47702f0b5d0b96b680199910b89f688.tar.gz lwn-6ad8bc92a47702f0b5d0b96b680199910b89f688.zip | |
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: Christian Hopps <chopps@labn.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
| -rw-r--r-- | include/linux/skbuff.h | 1 | ||||
| -rw-r--r-- | net/core/skbuff.c | 35 |
2 files changed, 36 insertions, 0 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 29c3ea5b6e93..a871533b8568 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -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); diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 83f8cd8aa2d1..fe4b2dc5c19b 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -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, |