Make use of stateful compression implemented in context.c.
The code does not impact current stateless compression.
Signed-off-by: Lukasz Duda <lukasz.duda@xxxxxxxxxxxxx>
Signed-off-by: Glenn Ruben Bakke <glenn.ruben.bakke@xxxxxxxxxxxxx>
---
net/6lowpan/iphc.c | 232 ++++++++++++++++++++++++++++++++++++++++++++---------
1 file changed, 196 insertions(+), 36 deletions(-)
diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
index c845a8a..48267e9 100644
--- a/net/6lowpan/iphc.c
+++ b/net/6lowpan/iphc.c
@@ -56,10 +56,63 @@
#include <net/af_ieee802154.h>
#include "nhc.h"
+#include "context.h"
+
+#define CTX_SRC(context) ((context & 0xf0) >> 4)
+#define CTX_DEST(context) (context & 0x0f)
+#define CID_NOT_USED 0xff
struct dentry *lowpan_debugfs;
EXPORT_SYMBOL_GPL(lowpan_debugfs);
+/* Add context prefix into given IPv6 address.
+ * Context prefix is always used, therefore any original bits can be
+ * overwritten.
+ */
+static inline void add_cid_prefix(struct in6_addr *ipaddr,
+ struct lowpan_context_entry *ctx_entry)
+{
+ int o = ctx_entry->prefix_len >> 3;
+ int b = ctx_entry->prefix_len & 0x7;
+
+ memcpy(ipaddr->s6_addr, ctx_entry->prefix.s6_addr, o);
+
+ if (b != 0)
+ ipaddr->s6_addr[o] = ctx_entry->prefix.s6_addr[o] &
+ (0xff00 >> b);
+}
+
+/* Check if address can be fully compressed with stateful compression. */
+static inline bool is_iid_compressable(struct in6_addr *ipaddr,
+ unsigned int ctx_length,
+ u8 *lladdr)
+{
+ unsigned int start_byte, offset;
+
+ /* Context covers IPv6 address by its size. */
+ if (ctx_length == 128)
+ return true;
+
+ /* Check if IID can be retrieved when prefix is longer than 64 bits. */
+ if (ctx_length > 64) {
+ /* Check only IID bytes that are not covered by context. */
+ start_byte = ctx_length >> 3;
+ offset = ctx_length % 8;
+
+ /* Check all bytes from the second one. */
+ if (start_byte == 15 ||
+ !memcmp(&ipaddr->s6_addr[start_byte + 1],
+ &lladdr[start_byte - 7],
+ 15 - start_byte)) {
+ /* Then check first byte. */
+ return (u8)(ipaddr->s6_addr[start_byte] << offset) ==
+ (u8)(lladdr[start_byte - 8] << offset);
+ }
+ }
+
+ return false;
+}
+
/* Uncompress address function for source and
* destination address(non-multicast).
*
@@ -141,34 +194,82 @@ static int uncompress_addr(struct sk_buff *skb,
return 0;
}
-/* Uncompress address function for source context
- * based address(non-multicast).
- */
-static int uncompress_context_based_src_addr(struct sk_buff *skb,
- struct in6_addr *ipaddr,
- const u8 sam)
+/* Uncompress address after stateful compression. */
+static int uncompress_context_based_addr(struct sk_buff *skb,
+ struct net_device *dev,
+ struct in6_addr *ipaddr,
+ const u8 address_mode,
+ const u8 *lladdr,
+ const u8 addr_type,
+ const u8 addr_len,
+ const u8 context_id)
{
- switch (sam) {
- case LOWPAN_IPHC_ADDR_00:
- /* unspec address ::
+ bool fail = false;
+ struct lowpan_context_entry *ctx_entry;
+
+ if (address_mode == LOWPAN_IPHC_ADDR_00)
+ /* Unspecified address ::
* Do nothing, address is already ::
*/
- break;
+ return 0;
+
+ /* Look for prefix assigned to given context id. */
+ ctx_entry = lowpan_context_decompress(dev, context_id);
+ if (!ctx_entry) {
+ pr_debug("Unknown Context. Unable to decompress\n");
+ return -EINVAL;
+ }
+
+ switch (address_mode) {
case LOWPAN_IPHC_ADDR_01:
- /* TODO */
+ /* CID Prefix + 64-bits in-line. */
+ fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
+ break;
case LOWPAN_IPHC_ADDR_02:
- /* TODO */
+ /* CID Prefix + 16-bits in-line. */
+ 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:
- /* TODO */
- netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam);
- return -EINVAL;
+ switch (addr_type) {
+ case IEEE802154_ADDR_LONG:
+ /* CID Prefix + 64-bits from LL Address. */
+ 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:
+ /* CID Prefix + 16-bits from LL Address. */
+ 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 sam value: 0x%x\n", sam);
+ pr_debug("Invalid address mode value: 0x%x\n",
+ address_mode);
return -EINVAL;
}
- raw_dump_inline(NULL,
- "Reconstructed context based ipv6 src addr is",
+ if (fail) {
+ pr_debug("Failed to fetch skb data\n");
+ return -EIO;
+ }
+
+ /* Add context prefix to IPv6 address. Context bits are always used. */
+ add_cid_prefix(ipaddr, ctx_entry);
+
+ raw_dump_inline(NULL, "Reconstructed ipv6 addr is",
ipaddr->s6_addr, 16);
return 0;
@@ -323,11 +424,14 @@ lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev,
if (iphc1 & LOWPAN_IPHC_SAC) {
/* Source address context based uncompression */
- pr_debug("SAC bit is set. Handle context based source address.\n");
- err = uncompress_context_based_src_addr(skb, &hdr.saddr, tmp);
+ pr_debug("source: address stateful compression.\n");
+ err = uncompress_context_based_addr(skb, dev, &hdr.saddr,
+ tmp, saddr, saddr_type,
+ saddr_len,
+ CTX_SRC(num_context));
} else {
/* Source address uncompression */
- pr_debug("source address stateless compression\n");
+ pr_debug("source: address stateless compression\n");
err = uncompress_addr(skb, &hdr.saddr, tmp, saddr,
saddr_type, saddr_len);
}
@@ -352,10 +456,19 @@ lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev,
return -EINVAL;
}
} else {
- err = uncompress_addr(skb, &hdr.daddr, tmp, daddr,
- daddr_type, daddr_len);
- pr_debug("dest: stateless compression mode %d dest %pI6c\n",
- tmp, &hdr.daddr);
+ if (iphc1 & LOWPAN_IPHC_DAC) {
+ /* Destination address context based uncompression */
+ pr_debug("dest: address steteful compression.\n");
+ err = uncompress_context_based_addr(
+ skb, dev, &hdr.daddr, tmp, daddr, daddr_type,
+ daddr_len, CTX_DEST(num_context));
+ } else {
+ /* Destination address uncompression */
+ pr_debug("dest: address stateless compression\n");
+ err = uncompress_addr(skb, &hdr.daddr, tmp, daddr,
+ daddr_type, daddr_len);
+ }
+
if (err)
return -EINVAL;
}
@@ -393,11 +506,12 @@ EXPORT_SYMBOL_GPL(lowpan_header_decompress);
static u8 lowpan_compress_addr_64(u8 **hc_ptr, u8 shift,
const struct in6_addr *ipaddr,
- const unsigned char *lladdr)
+ const unsigned char *lladdr,
+ bool cover_by_context)
{
u8 val = 0;
- if (is_addr_mac_addr_based(ipaddr, lladdr)) {
+ if (is_addr_mac_addr_based(ipaddr, lladdr) || cover_by_context) {
val = 3; /* 0-bits */
pr_debug("address compression 0 bits\n");
} else if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
@@ -422,9 +536,15 @@ int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
const void *_saddr, unsigned int len)
{
u8 tmp, iphc0, iphc1, *hc_ptr;
+ u8 cid = 0;
struct ipv6hdr *hdr;
u8 head[100] = {};
int ret, addr_type;
+ struct lowpan_context_entry *entry;
+ bool scid_used = false;
+ bool dcid_used = false;
+ bool scid_cover = false;
+ bool dcid_cover = false;
if (type != ETH_P_IPV6)
return -EINVAL;
@@ -448,7 +568,26 @@ int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
iphc0 = LOWPAN_DISPATCH_IPHC;
iphc1 = 0;
- /* TODO: context lookup */
+ /* Look for source context. */
+ entry = lowpan_context_compress(dev, &hdr->saddr);
+ if (entry) {
+ cid = entry->cid << 4;
+ scid_used = true;
+ }
+
+ /* Look for destination context. */
+ entry = lowpan_context_compress(dev, &hdr->daddr);
+ if (entry) {
+ cid |= entry->cid;
+ dcid_used = true;
+ }
+
+ if (scid_used || dcid_used) {
+ /* Add CID flag. */
+ iphc1 |= LOWPAN_IPHC_CID;
+
+ lowpan_push_hc_data(&hc_ptr, &cid, 1);
+ }
raw_dump_inline(__func__, "saddr",
(unsigned char *)_saddr, IEEE802154_ADDR_LEN);
@@ -535,11 +674,19 @@ int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
pr_debug("source address is unspecified, setting SAC\n");
iphc1 |= LOWPAN_IPHC_SAC;
} else {
- if (addr_type & IPV6_ADDR_LINKLOCAL) {
+ if ((addr_type & IPV6_ADDR_LINKLOCAL) || scid_used) {
+ if (scid_used) {
+ iphc1 |= LOWPAN_IPHC_SAC;
+ scid_cover = is_iid_compressable(
+ &hdr->saddr, entry->prefix_len,
+ (u8 *)_saddr);
+ }
+
iphc1 |= lowpan_compress_addr_64(&hc_ptr,
LOWPAN_IPHC_SAM_BIT,
- &hdr->saddr, _saddr);
- pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n",
+ &hdr->saddr, _saddr,
+ scid_cover);
+ pr_debug("source ipv6 address %pI6c iphc1 0x%02x\n",
&hdr->saddr, iphc1);
} else {
pr_debug("send the full source address\n");
@@ -580,12 +727,20 @@ int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16);
}
} else {
- if (addr_type & IPV6_ADDR_LINKLOCAL) {
- /* TODO: context lookup */
+ if (addr_type & IPV6_ADDR_LINKLOCAL || dcid_used) {
+ if (dcid_used) {
+ iphc1 |= LOWPAN_IPHC_DAC;
+ dcid_cover = is_iid_compressable(
+ &hdr->daddr, entry->prefix_len,
+ (u8 *)_daddr);
+ }
+
iphc1 |= lowpan_compress_addr_64(&hc_ptr,
- LOWPAN_IPHC_DAM_BIT, &hdr->daddr, _daddr);
- pr_debug("dest address unicast link-local %pI6c "
- "iphc1 0x%02x\n", &hdr->daddr, iphc1);
+ LOWPAN_IPHC_DAM_BIT,
+ &hdr->daddr, _daddr,
+ dcid_cover);
+ pr_debug("dest address %pI6c iphc1 0x%02x\n",
+ &hdr->daddr, iphc1);
} else {
pr_debug("dest address unicast %pI6c\n", &hdr->daddr);
lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16);
@@ -619,6 +774,9 @@ static int __init lowpan_module_init(void)
{
lowpan_debugfs = debugfs_create_dir("6lowpan", NULL);
+ /* Initialize stateful compression. */
+ lowpan_context_init();
+
request_module_nowait("ipv6");
request_module_nowait("nhc_dest");
@@ -635,6 +793,8 @@ static int __init lowpan_module_init(void)
static void __exit lowpan_module_exit(void)
{
debugfs_remove(lowpan_debugfs);
+
+ lowpan_context_uninit();
}
module_init(lowpan_module_init);
--
2.1.4
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