diff mbox series

[02/13] net: add copy from skb_seq_state to buffer function

Message ID 20240910065507.2436394-3-steffen.klassert@secunet.com (mailing list archive)
State Accepted
Commit 6ad8bc92a47702f0b5d0b96b680199910b89f688
Delegated to: Netdev Maintainers
Headers show
Series [01/13] xfrm: Remove documentation WARN_ON to limit return values for offloaded SA | expand

Checks

Context Check Description
netdev/series_format warning Pull request is its own cover letter; Target tree name not specified in the subject
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 58 this patch: 58
netdev/build_tools success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 2 maintainers not CCed: pabeni@redhat.com edumazet@google.com
netdev/build_clang success Errors and warnings before: 116 this patch: 116
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 4957 this patch: 4957
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 48 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 113 this patch: 113
netdev/source_inline success Was 0 now: 0

Commit Message

Steffen Klassert Sept. 10, 2024, 6:54 a.m. UTC 
From: Christian Hopps <chopps@labn.net>

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>
---
 include/linux/skbuff.h |  1 +
 net/core/skbuff.c      | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)
diff mbox series

Patch

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,