Parse GRE v0 packets to properly set up inner offset, this allow for
matching on inner headers.
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/nft_payload.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c
index 07621d509a68..03a1f271bf4f 100644
--- a/net/netfilter/nft_payload.c
+++ b/net/netfilter/nft_payload.c
@@ -19,6 +19,7 @@
/* For layer 4 checksum field offset. */
#include <linux/tcp.h>
#include <linux/udp.h>
+#include <net/gre.h>
#include <linux/icmpv6.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
@@ -100,6 +101,37 @@ static int __nft_payload_inner_offset(struct nft_pktinfo *pkt)
pkt->inneroff = thoff + __tcp_hdrlen(th);
}
break;
+ case IPPROTO_GRE: {
+ u32 offset = sizeof(struct gre_base_hdr), version;
+ struct gre_base_hdr *gre, _gre;
+
+ gre = skb_header_pointer(pkt->skb, thoff, sizeof(_gre), &_gre);
+ if (!gre)
+ return -1;
+
+ version = gre->flags & GRE_VERSION;
+ switch (version) {
+ case GRE_VERSION_0:
+ if (gre->flags & GRE_ROUTING)
+ return -1;
+
+ if (gre->flags & GRE_CSUM) {
+ offset += sizeof_field(struct gre_full_hdr, csum) +
+ sizeof_field(struct gre_full_hdr, reserved1);
+ }
+ if (gre->flags & GRE_KEY)
+ offset += sizeof_field(struct gre_full_hdr, key);
+
+ if (gre->flags & GRE_SEQ)
+ offset += sizeof_field(struct gre_full_hdr, seq);
+ break;
+ default:
+ return -1;
+ }
+
+ pkt->inneroff = thoff + offset;
+ }
+ break;
default:
return -1;
}
--
2.30.2
