6lowpan: add udp warning for elided checksum
Bit 5 of "UDP LOWPAN_NHC Format" indicate that the checksum can be
elided.
The host need to calculate the udp checksum afterwards but this isn't
supported right now.
See:
http://tools.ietf.org/html/rfc6282#section-4.3.3
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/net/ieee802154/6lowpan.h b/net/ieee802154/6lowpan.h
index 4981bf8..2b835db 100644
--- a/net/ieee802154/6lowpan.h
+++ b/net/ieee802154/6lowpan.h
@@ -231,6 +231,7 @@
#define LOWPAN_NHC_UDP_CS_P_10 0xF2 /* source = 0xF0 + 8bit inline,
dest = 16 bit inline */
#define LOWPAN_NHC_UDP_CS_P_11 0xF3 /* source & dest = 0xF0B + 4bit inline */
+#define LOWPAN_NHC_UDP_CS_C 0x04 /* checksum elided */
#ifdef DEBUG
/* print data in line */
diff --git a/net/ieee802154/6lowpan_iphc.c b/net/ieee802154/6lowpan_iphc.c
index 02bf74d..a70fa66 100644
--- a/net/ieee802154/6lowpan_iphc.c
+++ b/net/ieee802154/6lowpan_iphc.c
@@ -309,9 +309,14 @@
pr_debug("uncompressed UDP ports: src = %d, dst = %d\n",
ntohs(uh->source), ntohs(uh->dest));
- /* copy checksum */
- memcpy(&uh->check, &skb->data[0], 2);
- skb_pull(skb, 2);
+ /* checksum */
+ if (tmp & LOWPAN_NHC_UDP_CS_C) {
+ pr_debug_ratelimited("checksum elided currently not supported\n");
+ goto err;
+ } else {
+ memcpy(&uh->check, &skb->data[0], 2);
+ skb_pull(skb, 2);
+ }
/*
* UDP lenght needs to be infered from the lower layers