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Commit 5203cd28 authored by Jason Wang's avatar Jason Wang Committed by David S. Miller
Browse files

net: core: introduce skb_probe_transport_header() 



Sometimes, we need probe and set the transport header for packets (e.g from
untrusted source). This patch introduces a new helper
skb_probe_transport_header() which tries to probe and set the l4 header through
skb_flow_dissect(), if not just set the transport header to the hint passed by
caller.

Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e5d5deca

include/linux/skbuff.h

+14 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 
#include <linux/hrtimer.h>

#include <linux/dma-mapping.h>

#include <linux/netdev_features.h>

#include <net/flow_keys.h>



/* Don't change this without changing skb_csum_unnecessary! */

#define CHECKSUM_NONE 0
@@ -1559,6 +1560,19 @@ static inline void skb_set_transport_header(struct sk_buff *skb, 
	skb->transport_header += offset;

}



static inline void skb_probe_transport_header(struct sk_buff *skb,

					      const int offset_hint)

{

	struct flow_keys keys;



	if (skb_transport_header_was_set(skb))

		return;

	else if (skb_flow_dissect(skb, &keys))

		skb_set_transport_header(skb, keys.thoff);

	else

		skb_set_transport_header(skb, offset_hint);

}



static inline unsigned char *skb_network_header(const struct sk_buff *skb)

{

	return skb->head + skb->network_header;