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>
This commit is contained in:
Alexander Aring 2013-12-17 14:21:25 +01:00 committed by Marcel Holtmann
parent e5d966eff3
commit 573701ce37
2 changed files with 9 additions and 3 deletions

View file

@ -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 */

View file

@ -309,9 +309,14 @@ uncompress_udp_header(struct sk_buff *skb, struct udphdr *uh)
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