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 <eduma...@google.com>
Signed-off-by: Jason Wang <jasow...@redhat.com>
---
include/linux/skbuff.h | 14 ++++++++++++++
1 files changed, 14 insertions(+), 0 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 4974121..fa88b96 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -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;
--
1.7.1
--
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