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;
}
void lowpan_netdev_setup(struct net_device *dev, enum lowpan_lltypes lltype)
{
lowpan_priv(dev)->lltype = lltype;
}
