6lowpan: add function to uncompress multicast addr
Add function to uncompress multicast address.
This function split the uncompress function for a multicast address
in a seperate function.
To uncompress a multicast address is different than a other
non-multicasts addresses according to rfc6282.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Reviewed-by: Werner Almesberger <werner@almesberger.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index 632b3fd..9aea7ce 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -88,15 +88,6 @@
*/
static const u8 lowpan_unc_ctxconf[] = {0x00, 0x88, 0x82, 0x80};
-/*
- * Uncompression of ctx-base
- * 0 -> 0 bits from packet
- * 1 -> 2 bytes from prefix - bunch of zeroes 5 from packet
- * 2 -> 2 bytes from prefix - zeroes + 3 from packet
- * 3 -> 2 bytes from prefix - infer 1 bytes from lladdr
- */
-static const u8 lowpan_unc_mxconf[] = {0x0f, 0x25, 0x23, 0x21};
-
/* Link local prefix */
static const u8 lowpan_llprefix[] = {0xfe, 0x80};
@@ -240,6 +231,63 @@
return 0;
}
+/* 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;
+ }
+
+ lowpan_raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is:\n",
+ ipaddr->s6_addr, 16);
+
+ return 0;
+}
+
static void
lowpan_compress_udp_header(u8 **hc06_ptr, struct sk_buff *skb)
{
@@ -927,16 +975,8 @@
pr_debug("dest: context-based mcast compression\n");
/* TODO: implement this */
} else {
- u8 prefix[] = {0xff, 0x02};
-
- pr_debug("dest: non context-based mcast compression\n");
- if (0 < tmp && tmp < 3) {
- if (lowpan_fetch_skb_u8(skb, &prefix[1]))
- goto drop;
- }
-
- err = lowpan_uncompress_addr(skb, &hdr.daddr, prefix,
- lowpan_unc_mxconf[tmp], NULL);
+ err = lowpan_uncompress_multicast_daddr(
+ skb, &hdr.daddr, tmp);
if (err)
goto drop;
}