ipv6: Add fragment reporting to ipv6_skip_exthdr().
While parsing through IPv6 extension headers, fragment headers are
skipped making them invisible to the caller. This reports the
fragment offset of the last header in order to make it possible to
determine whether the packet is fragmented and, if so whether it is
a first or last fragment.
Signed-off-by: Jesse Gross <jesse@nicira.com>
diff --git a/net/ipv6/exthdrs_core.c b/net/ipv6/exthdrs_core.c
index 37f548b..72957f4a 100644
--- a/net/ipv6/exthdrs_core.c
+++ b/net/ipv6/exthdrs_core.c
@@ -57,6 +57,9 @@
* it returns NULL.
* - First fragment header is skipped, not-first ones
* are considered as unparsable.
+ * - Reports the offset field of the final fragment header so it is
+ * possible to tell whether this is a first fragment, later fragment,
+ * or not fragmented.
* - ESP is unparsable for now and considered like
* normal payload protocol.
* - Note also special handling of AUTH header. Thanks to IPsec wizards.
@@ -64,10 +67,13 @@
* --ANK (980726)
*/
-int ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp)
+int ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp,
+ __be16 *frag_offp)
{
u8 nexthdr = *nexthdrp;
+ *frag_offp = 0;
+
while (ipv6_ext_hdr(nexthdr)) {
struct ipv6_opt_hdr _hdr, *hp;
int hdrlen;
@@ -87,7 +93,8 @@
if (fp == NULL)
return -1;
- if (ntohs(*fp) & ~0x7)
+ *frag_offp = *fp;
+ if (ntohs(*frag_offp) & ~0x7)
break;
hdrlen = 8;
} else if (nexthdr == NEXTHDR_AUTH)
