Beispiel #1
0
static int udp_uncompress(struct sk_buff *skb, size_t needed)
{
	u8 tmp = 0, val = 0;
	struct udphdr uh;
	bool fail;
	int err;

	fail = lowpan_fetch_skb(skb, &tmp, sizeof(tmp));

	pr_debug("UDP header uncompression\n");
	switch (tmp & LOWPAN_NHC_UDP_CS_P_11) {
	case LOWPAN_NHC_UDP_CS_P_00:
		fail |= lowpan_fetch_skb(skb, &uh.source, sizeof(uh.source));
		fail |= lowpan_fetch_skb(skb, &uh.dest, sizeof(uh.dest));
		break;
	case LOWPAN_NHC_UDP_CS_P_01:
		fail |= lowpan_fetch_skb(skb, &uh.source, sizeof(uh.source));
		fail |= lowpan_fetch_skb(skb, &val, sizeof(val));
		uh.dest = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
		break;
	case LOWPAN_NHC_UDP_CS_P_10:
		fail |= lowpan_fetch_skb(skb, &val, sizeof(val));
		uh.source = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
		fail |= lowpan_fetch_skb(skb, &uh.dest, sizeof(uh.dest));
		break;
	case LOWPAN_NHC_UDP_CS_P_11:
		fail |= lowpan_fetch_skb(skb, &val, sizeof(val));
		uh.source = htons(LOWPAN_NHC_UDP_4BIT_PORT + (val >> 4));
		uh.dest = htons(LOWPAN_NHC_UDP_4BIT_PORT + (val & 0x0f));
		break;
	default:
		BUG();
	}

	pr_debug("uncompressed UDP ports: src = %d, dst = %d\n",
		 ntohs(uh.source), ntohs(uh.dest));

	/* checksum */
	if (tmp & LOWPAN_NHC_UDP_CS_C) {
		pr_debug_ratelimited("checksum elided currently not supported\n");
		fail = true;
	} else {
		fail |= lowpan_fetch_skb(skb, &uh.check, sizeof(uh.check));
	}

	if (fail)
		return -EINVAL;

	/* UDP length needs to be infered from the lower layers
	 * here, we obtain the hint from the remaining size of the
	 * frame
	 */
	switch (lowpan_priv(skb->dev)->lltype) {
	case LOWPAN_LLTYPE_IEEE802154:
		if (lowpan_802154_cb(skb)->d_size)
			uh.len = htons(lowpan_802154_cb(skb)->d_size -
				       sizeof(struct ipv6hdr));
		else
			uh.len = htons(skb->len + sizeof(struct udphdr));
		break;
	default:
		uh.len = htons(skb->len + sizeof(struct udphdr));
		break;
	}
	pr_debug("uncompressed UDP length: src = %d", ntohs(uh.len));

	/* replace the compressed UDP head by the uncompressed UDP
	 * header
	 */
	err = skb_cow(skb, needed);
	if (unlikely(err))
		return err;

	skb_push(skb, sizeof(struct udphdr));
	skb_copy_to_linear_data(skb, &uh, sizeof(struct udphdr));

	return 0;
}
Beispiel #2
0
void lowpan_netdev_setup(struct net_device *dev, enum lowpan_lltypes lltype)
{
	lowpan_priv(dev)->lltype = lltype;
}