[RFC PATCH net-next 3/8] skb: Add skb_push_uchar
From: Joe Perches <joe@perches.com>
Date: 2015-05-04 20:06:10
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
skb_push currently returns an unsigned char *. There are uses like "*skb_push(skb, 1) = <char>" that might be better represented by a new skb_push_uchar(<char>) function. This would allow the skb_push function to be converted to return void and eliminate many casts of the unsigned char * return to some other type. Signed-off-by: Joe Perches <joe@perches.com> --- include/linux/skbuff.h | 1 + net/core/skbuff.c | 22 ++++++++++++++++++++++ 2 files changed, 23 insertions(+)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 894071e1..30cd234 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h@@ -1690,6 +1690,7 @@ static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len) } unsigned char *skb_push(struct sk_buff *skb, unsigned int len); +void *skb_push_uchar(struct sk_buff *skb, unsigned char uc); static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len) { skb->data -= len;
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 73e20ad..b092d2b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c@@ -1455,6 +1455,28 @@ unsigned char *skb_push(struct sk_buff *skb, unsigned int len) EXPORT_SYMBOL(skb_push); /** + * skb_push_uchar - add an unsigned char to the start of a buffer + * @skb: buffer to use + * @uc: unsigned char to add + * + * This function extends the used data area of the buffer at the buffer + * start. If this would exceed the total buffer headroom the kernel will + * panic. A pointer to the first byte of the extra data is returned. + */ +void *skb_push_uchar(struct sk_buff *skb, unsigned char uc) +{ + skb->data--; + skb->len++; + if (unlikely(skb->data<skb->head)) + skb_under_panic(skb, 1, __builtin_return_address(0)); + + *skb->data = uc; + + return skb->data; +} +EXPORT_SYMBOL(skb_push_uchar); + +/** * skb_pull - remove data from the start of a buffer * @skb: buffer to use * @len: amount of data to remove
--
2.1.4