6LoWPAN: UDP header decompression
This patch provides possibility to decompress UDP headers.
Derived from Contiki OS.
Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index 9bf82d7..602f318 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -311,6 +311,62 @@
return ret;
}
+static int
+lowpan_uncompress_udp_header(struct sk_buff *skb)
+{
+ struct udphdr *uh = udp_hdr(skb);
+ u8 tmp;
+
+ tmp = lowpan_fetch_skb_u8(skb);
+
+ if ((tmp & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) {
+ pr_debug("(%s): UDP header uncompression\n", __func__);
+ switch (tmp & LOWPAN_NHC_UDP_CS_P_11) {
+ case LOWPAN_NHC_UDP_CS_P_00:
+ memcpy(&uh->source, &skb->data[0], 2);
+ memcpy(&uh->dest, &skb->data[2], 2);
+ skb_pull(skb, 4);
+ break;
+ case LOWPAN_NHC_UDP_CS_P_01:
+ memcpy(&uh->source, &skb->data[0], 2);
+ uh->dest =
+ skb->data[2] + LOWPAN_NHC_UDP_8BIT_PORT;
+ skb_pull(skb, 3);
+ break;
+ case LOWPAN_NHC_UDP_CS_P_10:
+ uh->source = skb->data[0] + LOWPAN_NHC_UDP_8BIT_PORT;
+ memcpy(&uh->dest, &skb->data[1], 2);
+ skb_pull(skb, 3);
+ break;
+ case LOWPAN_NHC_UDP_CS_P_11:
+ uh->source =
+ LOWPAN_NHC_UDP_4BIT_PORT + (skb->data[0] >> 4);
+ uh->dest =
+ LOWPAN_NHC_UDP_4BIT_PORT + (skb->data[0] & 0x0f);
+ skb_pull(skb, 1);
+ break;
+ default:
+ pr_debug("(%s) ERROR: unknown UDP format\n", __func__);
+ goto err;
+ break;
+ }
+
+ pr_debug("(%s): uncompressed UDP ports: src = %d, dst = %d\n",
+ __func__, uh->source, uh->dest);
+
+ /* copy checksum */
+ memcpy(&uh->check, &skb->data[0], 2);
+ skb_pull(skb, 2);
+ } else {
+ pr_debug("(%s): ERROR: unsupported NH format\n", __func__);
+ goto err;
+ }
+
+ return 0;
+err:
+ return -EINVAL;
+}
+
static int lowpan_header_create(struct sk_buff *skb,
struct net_device *dev,
unsigned short type, const void *_daddr,
@@ -842,7 +898,10 @@
goto drop;
}
- /* TODO: UDP header parse */
+ /* UDP data uncompression */
+ if (iphc0 & LOWPAN_IPHC_NH_C)
+ if (lowpan_uncompress_udp_header(skb))
+ goto drop;
/* Not fragmented package */
hdr.payload_len = htons(skb->len);