static int lowpan_get_frag_info(struct sk_buff *skb, const u8 frag_type,
struct lowpan_frag_info *frag_info)
{
bool fail;
u8 pattern = 0, low = 0;
__be16 d_tag = 0;
fail = lowpan_fetch_skb(skb, &pattern, 1);
fail |= lowpan_fetch_skb(skb, &low, 1);
frag_info->d_size = (pattern & 7) << 8 | low;
fail |= lowpan_fetch_skb(skb, &d_tag, 2);
frag_info->d_tag = ntohs(d_tag);
if (frag_type == LOWPAN_DISPATCH_FRAGN) {
fail |= lowpan_fetch_skb(skb, &frag_info->d_offset, 1);
} else {
skb_reset_network_header(skb);
frag_info->d_offset = 0;
}
if (unlikely(fail))
return -EIO;
return 0;
}
static int lowpan_get_cb(struct sk_buff *skb, u8 frag_type,
struct lowpan_802154_cb *cb)
{
bool fail;
u8 high = 0, low = 0;
__be16 d_tag = 0;
fail = lowpan_fetch_skb(skb, &high, 1);
fail |= lowpan_fetch_skb(skb, &low, 1);
/* remove the dispatch value and use first three bits as high value
* for the datagram size
*/
cb->d_size = (high & LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK) <<
LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT | low;
fail |= lowpan_fetch_skb(skb, &d_tag, 2);
cb->d_tag = ntohs(d_tag);
if (frag_type == LOWPAN_DISPATCH_FRAGN) {
fail |= lowpan_fetch_skb(skb, &cb->d_offset, 1);
} else {
skb_reset_network_header(skb);
cb->d_offset = 0;
/* check if datagram_size has ipv6hdr on FRAG1 */
fail |= cb->d_size < sizeof(struct ipv6hdr);
/* check if we can dereference the dispatch value */
fail |= !skb->len;
}
if (unlikely(fail))
return -EIO;
return 0;
}
static int uncompress_udp_header(struct sk_buff *skb, struct udphdr *uh)
{
bool fail;
u8 tmp = 0, val = 0;
fail = lowpan_fetch_skb(skb, &tmp, sizeof(tmp));
if ((tmp & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) {
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:
pr_debug("ERROR: unknown UDP format\n");
goto err;
}
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");
goto err;
} else {
fail |= lowpan_fetch_skb(skb, &uh->check,
sizeof(uh->check));
}
/* UDP length needs to be infered from the lower layers
* here, we obtain the hint from the remaining size of the
* frame
*/
uh->len = htons(skb->len + sizeof(struct udphdr));
pr_debug("uncompressed UDP length: src = %d", ntohs(uh->len));
} else {
/* Uncompress function for multicast destination address,
* when M bit is set.
*/
static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
struct in6_addr *ipaddr,
const u8 dam)
{
bool fail;
switch (dam) {
case LOWPAN_IPHC_DAM_00:
/* 00: 128 bits. The full address
* is carried in-line.
*/
fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
break;
case LOWPAN_IPHC_DAM_01:
/* 01: 48 bits. The address takes
* the form ffXX::00XX:XXXX:XXXX.
*/
ipaddr->s6_addr[0] = 0xFF;
fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5);
break;
case LOWPAN_IPHC_DAM_10:
/* 10: 32 bits. The address takes
* the form ffXX::00XX:XXXX.
*/
ipaddr->s6_addr[0] = 0xFF;
fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3);
break;
case LOWPAN_IPHC_DAM_11:
/* 11: 8 bits. The address takes
* the form ff02::00XX.
*/
ipaddr->s6_addr[0] = 0xFF;
ipaddr->s6_addr[1] = 0x02;
fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
break;
default:
pr_debug("DAM value has a wrong value: 0x%x\n", dam);
return -EINVAL;
}
if (fail) {
pr_debug("Failed to fetch skb data\n");
return -EIO;
}
raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is",
ipaddr->s6_addr, 16);
return 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;
}
/* Uncompress address function for source and
* destination address(non-multicast).
*
* address_mode is sam value or dam value.
*/
static int uncompress_addr(struct sk_buff *skb,
struct in6_addr *ipaddr, const u8 address_mode,
const u8 *lladdr, const u8 addr_type,
const u8 addr_len)
{
bool fail;
switch (address_mode) {
case LOWPAN_IPHC_ADDR_00:
/* for global link addresses */
fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
break;
case LOWPAN_IPHC_ADDR_01:
/* fe:80::XXXX:XXXX:XXXX:XXXX */
ipaddr->s6_addr[0] = 0xFE;
ipaddr->s6_addr[1] = 0x80;
fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
break;
case LOWPAN_IPHC_ADDR_02:
/* fe:80::ff:fe00:XXXX */
ipaddr->s6_addr[0] = 0xFE;
ipaddr->s6_addr[1] = 0x80;
ipaddr->s6_addr[11] = 0xFF;
ipaddr->s6_addr[12] = 0xFE;
fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
break;
case LOWPAN_IPHC_ADDR_03:
fail = false;
switch (addr_type) {
case IEEE802154_ADDR_LONG:
/* fe:80::XXXX:XXXX:XXXX:XXXX
* \_________________/
* hwaddr
*/
ipaddr->s6_addr[0] = 0xFE;
ipaddr->s6_addr[1] = 0x80;
memcpy(&ipaddr->s6_addr[8], lladdr, addr_len);
/* second bit-flip (Universe/Local)
* is done according RFC2464
*/
ipaddr->s6_addr[8] ^= 0x02;
break;
case IEEE802154_ADDR_SHORT:
/* fe:80::ff:fe00:XXXX
* \__/
* short_addr
*
* Universe/Local bit is zero.
*/
ipaddr->s6_addr[0] = 0xFE;
ipaddr->s6_addr[1] = 0x80;
ipaddr->s6_addr[11] = 0xFF;
ipaddr->s6_addr[12] = 0xFE;
ipaddr->s6_addr16[7] = htons(*((u16 *)lladdr));
break;
default:
pr_debug("Invalid addr_type set\n");
return -EINVAL;
}
break;
default:
pr_debug("Invalid address mode value: 0x%x\n", address_mode);
return -EINVAL;
}
if (fail) {
pr_debug("Failed to fetch skb data\n");
return -EIO;
}
raw_dump_inline(NULL, "Reconstructed ipv6 addr is",
ipaddr->s6_addr, 16);
return 0;
}
