ctx.h

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/*
 * Copyright (C) 2015 Martine Lenders <mlenders@inf.fu-berlin.de>
 *
 * This file is subject to the terms and conditions of the GNU Lesser
 * General Public License v2.1. See the file LICENSE in the top level
 * directory for more details.
 */
 
#pragma once
 
#include <inttypes.h>
#include <stdbool.h>
 
#include "net/ipv6/addr.h"
#include "timex.h"
#include "modules.h"
 
#ifdef __cplusplus
extern "C" {
#endif
 
#define GNRC_SIXLOWPAN_CTX_SIZE (16)    
#define GNRC_SIXLOWPAN_CTX_FLAGS_CID_MASK   (0x0f)  
#define GNRC_SIXLOWPAN_CTX_FLAGS_COMP       (0x10)  
typedef struct {
    ipv6_addr_t prefix;     
    uint8_t prefix_len;     
    uint8_t flags_id;
    uint16_t ltime;
} gnrc_sixlowpan_ctx_t;
 
gnrc_sixlowpan_ctx_t *gnrc_sixlowpan_ctx_lookup_addr(const ipv6_addr_t *addr);
 
gnrc_sixlowpan_ctx_t *gnrc_sixlowpan_ctx_lookup_id(uint8_t id);
 
gnrc_sixlowpan_ctx_t *gnrc_sixlowpan_ctx_update(uint8_t id, const ipv6_addr_t *prefix,
                                                uint8_t prefix_len, uint16_t ltime,
                                                bool comp);
 
static inline void gnrc_sixlowpan_ctx_remove(uint8_t id)
{
    if (IS_USED(MODULE_GNRC_SIXLOWPAN_CTX)) {
        gnrc_sixlowpan_ctx_lookup_id(id)->prefix_len = 0;
    }
}
 
static inline bool gnrc_sixlowpan_ctx_match(const gnrc_sixlowpan_ctx_t *ctx,
                                            const ipv6_addr_t *prefix, uint8_t prefix_len)
{
    return (ctx != NULL) &&
           (ctx->prefix_len == prefix_len) &&
           (ipv6_addr_match_prefix(&ctx->prefix, prefix) >= prefix_len);
}
 
static inline bool gnrc_sixlowpan_ctx_update_6ctx(const ipv6_addr_t *prefix, uint8_t prefix_len,
                                                  uint32_t valid)
{
    if (!IS_USED(MODULE_GNRC_SIXLOWPAN_CTX)) {
        return false;
    }
 
    gnrc_sixlowpan_ctx_t *ctx = gnrc_sixlowpan_ctx_lookup_addr(prefix);
    uint8_t cid = 0;
 
    if (!gnrc_sixlowpan_ctx_match(ctx, prefix, prefix_len)) {
        /* While the context is a prefix match, the defined prefix within the
         * context does not match => use new context */
        ctx = NULL;
    }
    else {
        cid = ctx->flags_id & GNRC_SIXLOWPAN_CTX_FLAGS_CID_MASK;
    }
    /* find first free context ID */
    if (ctx == NULL) {
        while (((ctx = gnrc_sixlowpan_ctx_lookup_id(cid)) != NULL) &&
               !gnrc_sixlowpan_ctx_match(ctx, prefix, prefix_len)) {
            cid++;
        }
    }
    if (cid < GNRC_SIXLOWPAN_CTX_SIZE) {
        return gnrc_sixlowpan_ctx_update(cid, (ipv6_addr_t *)prefix, prefix_len,
                                         valid / (60 * MS_PER_SEC),
                                         true);
    }
 
    return false;
}
 
#ifdef TEST_SUITES
void gnrc_sixlowpan_ctx_reset(void);
#endif
 
#ifdef __cplusplus
}
#endif