From 56193d1bce2b2759cb4bdcc00cd05544894a0c90 Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Fri, 5 Sep 2014 19:20:26 -0400 Subject: net: Add function for parsing the header length out of linear ethernet frames This patch updates some of the flow_dissector api so that it can be used to parse the length of ethernet buffers stored in fragments. Most of the changes needed were to __skb_get_poff as it needed to be updated to support sending a linear buffer instead of a skb. I have split __skb_get_poff into two functions, the first is skb_get_poff and it retains the functionality of the original __skb_get_poff. The other function is __skb_get_poff which now works much like __skb_flow_dissect in relation to skb_flow_dissect in that it provides the same functionality but works with just a data buffer and hlen instead of needing an skb. Signed-off-by: Alexander Duyck Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/linux/etherdevice.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/etherdevice.h') diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h index 9c5529dc6d07..733980fce8e3 100644 --- a/include/linux/etherdevice.h +++ b/include/linux/etherdevice.h @@ -29,6 +29,7 @@ #include #ifdef __KERNEL__ +u32 eth_get_headlen(void *data, unsigned int max_len); __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev); extern const struct header_ops eth_header_ops; -- cgit v1.2.3-59-g8ed1b From 9c0c112422a2a6b06fcddcaf21957676490cebba Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Wed, 3 Dec 2014 08:17:33 -0800 Subject: net: Add functions for handling padding frame and adding to length This patch adds two new helper functions skb_put_padto and eth_skb_pad. These functions deviate from the standard skb_pad or skb_padto in that they will also update the length and tail pointers so that they reflect the padding added to the frame. The eth_skb_pad helper is meant to be used with Ethernet devices to update either Rx or Tx frames so that they report the correct size. The skb_put_padto helper is meant to be used primarily in the transmit path for network devices that need frames to be padded up to some minimum size and don't wish to simply update the length somewhere external to the frame. The motivation behind this is that there are a number of implementations throughout the network device drivers that are all doing the same thing, but each a little bit differently and as a result several implementations contain bugs such as updating the length without updating the tail offset and other similar issues. Signed-off-by: Alexander Duyck Signed-off-by: David S. Miller --- include/linux/etherdevice.h | 12 ++++++++++++ include/linux/skbuff.h | 24 +++++++++++++++++++++++- 2 files changed, 35 insertions(+), 1 deletion(-) (limited to 'include/linux/etherdevice.h') diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h index 733980fce8e3..41c891d05f04 100644 --- a/include/linux/etherdevice.h +++ b/include/linux/etherdevice.h @@ -392,4 +392,16 @@ static inline unsigned long compare_ether_header(const void *a, const void *b) #endif } +/** + * eth_skb_pad - Pad buffer to mininum number of octets for Ethernet frame + * @skb: Buffer to pad + * + * An Ethernet frame should have a minimum size of 60 bytes. This function + * takes short frames and pads them with zeros up to the 60 byte limit. + */ +static inline int eth_skb_pad(struct sk_buff *skb) +{ + return skb_put_padto(skb, ETH_ZLEN); +} + #endif /* _LINUX_ETHERDEVICE_H */ diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 7691ad5b4771..d1e2575000b9 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2461,7 +2461,6 @@ static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom) * is untouched. Otherwise it is extended. Returns zero on * success. The skb is freed on error. */ - static inline int skb_padto(struct sk_buff *skb, unsigned int len) { unsigned int size = skb->len; @@ -2470,6 +2469,29 @@ static inline int skb_padto(struct sk_buff *skb, unsigned int len) return skb_pad(skb, len - size); } +/** + * skb_put_padto - increase size and pad an skbuff up to a minimal size + * @skb: buffer to pad + * @len: minimal length + * + * Pads up a buffer to ensure the trailing bytes exist and are + * blanked. If the buffer already contains sufficient data it + * is untouched. Otherwise it is extended. Returns zero on + * success. The skb is freed on error. + */ +static inline int skb_put_padto(struct sk_buff *skb, unsigned int len) +{ + unsigned int size = skb->len; + + if (unlikely(size < len)) { + len -= size; + if (skb_pad(skb, len)) + return -ENOMEM; + __skb_put(skb, len); + } + return 0; +} + static inline int skb_add_data(struct sk_buff *skb, char __user *from, int copy) { -- cgit v1.2.3-59-g8ed1b