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ng_sixlowpan_ctx: add compression flag support

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The compression flag allows a context to be invalidated for compression,
but still be valid for decompression. This is needed for context
dissimination in a LoWPAN.
This commit is contained in:
Martine Lenders 2015-06-02 17:21:36 +02:00 committed by Martine Lenders
parent 4a2af80e22
commit dd6ea99fd4
2 changed files with 46 additions and 30 deletions
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39
sys/include/net/ng_sixlowpan/ctx.h
View File

@ -30,6 +30,7 @@
#define NG_SIXLOWPAN_CTX_H_
#include <inttypes.h>
#include <stdbool.h>
#include "net/ng_ipv6/addr.h"
@ -40,6 +41,17 @@ extern "C" {
#define NG_SIXLOWPAN_CTX_SIZE (16) /**< maximum number of entries in
* context buffer */
/**
* @{
* @name Context flags.
* @brief Flags to set in ng_sixlowpan_ctx_t::flags_id.
*/
#define NG_SIXLOWPAN_CTX_FLAGS_CID_MASK (0x0f) /**< mask for the Context ID. */
#define NG_SIXLOWPAN_CTX_FLAGS_COMP (0x10) /**< Use context for compression */
/**
* @}
*/
/**
* @brief Entry in the 6LoWPAN context buffer.
*/
@ -47,12 +59,14 @@ typedef struct {
ng_ipv6_addr_t prefix; /**< The prefix associated to this context. */
uint8_t prefix_len; /**< Length of ng_sixlowpan_ctx_t::prefix in bit. */
/**
* @brief 4-bit Context ID.
* @brief 4-bit flags, 4-bit Context ID.
*
* @note This needs to be here to easily translate prefixes to
* ID.
*
* @details The flags are defined as above.
*/
uint8_t id;
uint8_t flags_id;
/**
* @brief Lifetime in minutes this context is valid.
*
@ -89,17 +103,28 @@ ng_sixlowpan_ctx_t *ng_sixlowpan_ctx_lookup_id(uint8_t id);
* @param[in] id The ID for the context.
* Must be < @ref NG_SIXLOWPAN_CTX_SIZE.
* @param[in] prefix The prefix for the context.
* @param[in] prefix_len Length of @p prefix in bits. Must be > 0, when
* @p ltime > 0.
* @param[in] ltime New lifetime of the context. The context will
* be removed if 0.
* @param[in] prefix_len Length of @p prefix in bits. Must be > 0.
* @param[in] ltime New lifetime of the context. @p comp will be
* implicitly set to `false` if @p ltime == 0.
* @param[in] comp Use for compression if true, do not use for
* compression, but still for decompression if false.
*
* @return The new context on success.
* @return NULL, on error or on removal.
*/
ng_sixlowpan_ctx_t *ng_sixlowpan_ctx_update(uint8_t id, const ng_ipv6_addr_t *prefix,
uint8_t prefix_len, uint16_t ltime);
uint8_t prefix_len, uint16_t ltime,
bool comp);
/**
* @brief Removes context.
*
* @param[in] id A context ID.
*/
static inline void ng_sixlowpan_ctx_remove(uint8_t id)
{
ng_sixlowpan_ctx_lookup_id(id)->prefix_len = 0;
}
#ifdef TEST_SUITES
/**

37
sys/net/network_layer/ng_sixlowpan/ctx/ng_sixlowpan_ctx.c
View File

@ -27,16 +27,16 @@ static uint32_t _ctx_inval_times[NG_SIXLOWPAN_CTX_SIZE];
static mutex_t _ctx_mutex = MUTEX_INIT;
static uint32_t _current_minute(void);
static void _update_lifetime(unsigned int id);
static void _update_lifetime(uint8_t id);
#if ENABLE_DEBUG
static char ipv6str[NG_IPV6_ADDR_MAX_STR_LEN];
#endif
static inline bool _still_valid(unsigned int id)
static inline bool _valid(uint8_t id)
{
_update_lifetime(id);
return (_ctxs[id].ltime > 0);
return (_ctxs[id].prefix_len > 0);
}
ng_sixlowpan_ctx_t *ng_sixlowpan_ctx_lookup_addr(const ng_ipv6_addr_t *addr)
@ -47,7 +47,7 @@ ng_sixlowpan_ctx_t *ng_sixlowpan_ctx_lookup_addr(const ng_ipv6_addr_t *addr)
mutex_lock(&_ctx_mutex);
for (unsigned int id = 0; id < NG_SIXLOWPAN_CTX_SIZE; id++) {
if (_still_valid(id)) {
if (_valid(id)) {
uint8_t match = ng_ipv6_addr_match_prefix(&_ctxs[id].prefix, addr);
if ((_ctxs[id].prefix_len <= match) && (match > best)) {
@ -79,7 +79,7 @@ ng_sixlowpan_ctx_t *ng_sixlowpan_ctx_lookup_id(uint8_t id)
mutex_lock(&_ctx_mutex);
if (_still_valid((unsigned int)id)) {
if (_valid(id)) {
DEBUG("6lo ctx: found context (%u, %s/%" PRIu8 ")\n", id,
ng_ipv6_addr_to_str(ipv6str, &_ctxs[id].prefix, sizeof(ipv6str)),
_ctxs[id].prefix_len);
@ -93,9 +93,10 @@ ng_sixlowpan_ctx_t *ng_sixlowpan_ctx_lookup_id(uint8_t id)
}
ng_sixlowpan_ctx_t *ng_sixlowpan_ctx_update(uint8_t id, const ng_ipv6_addr_t *prefix,
uint8_t prefix_len, uint16_t ltime)
uint8_t prefix_len, uint16_t ltime,
bool comp)
{
if ((id >= NG_SIXLOWPAN_CTX_SIZE)) {
if ((id >= NG_SIXLOWPAN_CTX_SIZE) || (prefix_len == 0)) {
return NULL;
}
@ -104,19 +105,7 @@ ng_sixlowpan_ctx_t *ng_sixlowpan_ctx_update(uint8_t id, const ng_ipv6_addr_t *pr
_ctxs[id].ltime = ltime;
if (ltime == 0) {
mutex_unlock(&_ctx_mutex);
DEBUG("6lo ctx: remove context (%u, %s/%" PRIu8 ")\n", id,
ng_ipv6_addr_to_str(ipv6str, &_ctxs[id].prefix, sizeof(ipv6str)),
_ctxs[id].prefix_len);
return NULL;
}
/* test prefix_len now so that invalidation is possible regardless of the
* value. */
if (prefix_len == 0) {
mutex_unlock(&_ctx_mutex);
_ctxs[id].ltime = 0;
return NULL;
comp = false;
}
if (prefix_len > NG_IPV6_ADDR_BIT_LEN) {
@ -126,7 +115,7 @@ ng_sixlowpan_ctx_t *ng_sixlowpan_ctx_update(uint8_t id, const ng_ipv6_addr_t *pr
_ctxs[id].prefix_len = prefix_len;
}
_ctxs[id].id = id;
_ctxs[id].flags_id = (comp) ? (NG_SIXLOWPAN_CTX_FLAGS_COMP | id) : id;
if (!ng_ipv6_addr_equal(&(_ctxs[id].prefix), prefix)) {
ng_ipv6_addr_set_unspecified(&(_ctxs[id].prefix));
@ -150,19 +139,21 @@ static uint32_t _current_minute(void)
return now.seconds / 60;
}
static void _update_lifetime(unsigned int id)
static void _update_lifetime(uint8_t id)
{
uint32_t now;
if (_ctxs[id].ltime == 0) {
_ctxs[id].flags_id &= ~NG_SIXLOWPAN_CTX_FLAGS_COMP;
return;
}
now = _current_minute();
if (now >= _ctx_inval_times[id]) {
DEBUG("6lo ctx: context %u was invalidated\n", id);
DEBUG("6lo ctx: context %u was invalidated for compression\n", id);
_ctxs[id].ltime = 0;
_ctxs[id].flags_id &= ~NG_SIXLOWPAN_CTX_FLAGS_COMP;
}
else {
_ctxs[id].ltime = (uint16_t)(_ctx_inval_times[id] - now);