ipv4_prefix.c

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#define _GNU_SOURCE /* strndup */

#include "plugins_internal.h"
#include "plugins_types.h"

#ifdef _WIN32
# include <winsock2.h>
# include <ws2tcpip.h>
#else
#  include <arpa/inet.h>
#  if defined (__FreeBSD__) || defined (__NetBSD__) || defined (__OpenBSD__)
#    include <netinet/in.h>
#    include <sys/socket.h>
#  endif
#endif
#include <assert.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#include "libyang.h"

#include "compat.h"
#include "ly_common.h"

#define LYPLG_IPV4PREF_LYB_VALUE_SIZE 40

static void lyplg_type_free_ipv4_prefix(const struct ly_ctx *ctx, struct lyd_value *value);

static void
lyplg_type_lyb_size_ipv4_prefix(const struct lysc_type *UNUSED(type), enum lyplg_lyb_size_type *size_type,
        uint32_t *fixed_size_bits)
{
    *size_type = LYPLG_LYB_SIZE_FIXED_BITS;
    *fixed_size_bits = LYPLG_IPV4PREF_LYB_VALUE_SIZE;
}

static LY_ERR
ipv4prefix_str2ip(const char *value, uint32_t value_len, struct in_addr *addr, uint8_t *prefix, struct ly_err_item **err)
{
    LY_ERR ret = LY_SUCCESS;
    const char *pref_str;
    char *mask_str = NULL;

    /* it passed the pattern validation */
    pref_str = ly_strnchr(value, '/', value_len);
    ly_strntou8(pref_str + 1, value_len - (pref_str + 1 - value), prefix);

    /* get just the network prefix */
    mask_str = strndup(value, pref_str - value);
    LY_CHECK_ERR_GOTO(!mask_str, ret = LY_EMEM, cleanup);

    /* convert it to netword-byte order */
    if (inet_pton(AF_INET, mask_str, addr) != 1) {
        ret = ly_err_new(err, LY_EVALID, LYVE_DATA, NULL, NULL, "Failed to store IPv4 address \"%s\".", mask_str);
        goto cleanup;
    }

cleanup:
    free(mask_str);
    return ret;
}

static void
ipv4prefix_zero_host(struct in_addr *addr, uint8_t prefix)
{
    uint32_t i, mask;

    /* zero host bits */
    mask = 0;
    for (i = 0; i < 32; ++i) {
        mask <<= 1;
        if (prefix > i) {
            mask |= 1;
        }
    }
    mask = htonl(mask);
    addr->s_addr &= mask;
}

static LY_ERR
lyplg_type_store_ipv4_prefix(const struct ly_ctx *ctx, const struct lysc_type *type, const void *value, uint32_t value_size_bits,
        uint32_t options, LY_VALUE_FORMAT format, void *UNUSED(prefix_data), uint32_t hints,
        const struct lysc_node *UNUSED(ctx_node), const struct lysc_ext_instance *UNUSED(top_ext),
        struct lyd_value *storage, struct lys_glob_unres *UNUSED(unres), struct ly_err_item **err)
{
    LY_ERR ret = LY_SUCCESS;
    struct lyd_value_ipv4_prefix *val;
    uint32_t value_size;

    /* init storage */
    memset(storage, 0, sizeof *storage);
    LYPLG_TYPE_VAL_INLINE_PREPARE(storage, val);
    LY_CHECK_ERR_GOTO(!val, ret = LY_EMEM, cleanup);
    storage->realtype = type;

    /* check value length */
    ret = lyplg_type_check_value_size("ipv4-prefix", format, value_size_bits, LYPLG_LYB_SIZE_FIXED_BITS,
            LYPLG_IPV4PREF_LYB_VALUE_SIZE, &value_size, err);
    LY_CHECK_GOTO(ret, cleanup);

    if (format == LY_VALUE_LYB) {
        /* validation */
        if (((uint8_t *)value)[4] > 32) {
            ret = ly_err_new(err, LY_EVALID, LYVE_DATA, NULL, NULL, "Invalid LYB ipv4-prefix prefix length %" PRIu8 ".",
                    ((uint8_t *)value)[4]);
            goto cleanup;
        }

        /* store addr + prefix */
        memcpy(val, value, value_size);

        /* zero host */
        ipv4prefix_zero_host(&val->addr, val->prefix);

        /* success */
        goto cleanup;
    }

    /* check hints */
    ret = lyplg_type_check_hints(hints, value, value_size, type->basetype, NULL, err);
    LY_CHECK_GOTO(ret, cleanup);

    /* get the mask in network-byte order */
    ret = ipv4prefix_str2ip(value, value_size, &val->addr, &val->prefix, err);
    LY_CHECK_GOTO(ret, cleanup);

    /* zero host */
    ipv4prefix_zero_host(&val->addr, val->prefix);

    if (format == LY_VALUE_CANON) {
        /* store canonical value */
        if (options & LYPLG_TYPE_STORE_DYNAMIC) {
            ret = lydict_insert_zc(ctx, (char *)value, &storage->_canonical);
            options &= ~LYPLG_TYPE_STORE_DYNAMIC;
            LY_CHECK_GOTO(ret, cleanup);
        } else {
            ret = lydict_insert(ctx, value_size ? value : "", value_size, &storage->_canonical);
            LY_CHECK_GOTO(ret, cleanup);
        }
    }

cleanup:
    if (options & LYPLG_TYPE_STORE_DYNAMIC) {
        free((void *)value);
    }

    if (ret) {
        lyplg_type_free_ipv4_prefix(ctx, storage);
    }
    return ret;
}

static LY_ERR
lyplg_type_compare_ipv4_prefix(const struct ly_ctx *UNUSED(ctx), const struct lyd_value *val1,
        const struct lyd_value *val2)
{
    struct lyd_value_ipv4_prefix *v1, *v2;

    LYD_VALUE_GET(val1, v1);
    LYD_VALUE_GET(val2, v2);

    if (memcmp(v1, v2, sizeof *v1)) {
        return LY_ENOT;
    }
    return LY_SUCCESS;
}

static int
lyplg_type_sort_ipv4_prefix(const struct ly_ctx *UNUSED(ctx), const struct lyd_value *val1,
        const struct lyd_value *val2)
{
    struct lyd_value_ipv4_prefix *v1, *v2;

    LYD_VALUE_GET(val1, v1);
    LYD_VALUE_GET(val2, v2);

    return memcmp(v1, v2, sizeof *v1);
}

static const void *
lyplg_type_print_ipv4_prefix(const struct ly_ctx *ctx, const struct lyd_value *value, LY_VALUE_FORMAT format,
        void *UNUSED(prefix_data), ly_bool *dynamic, uint32_t *value_size_bits)
{
    struct lyd_value_ipv4_prefix *val;
    char *ret;

    LYD_VALUE_GET(value, val);

    if (format == LY_VALUE_LYB) {
        *dynamic = 0;
        if (value_size_bits) {
            *value_size_bits = LYPLG_IPV4PREF_LYB_VALUE_SIZE;
        }
        return val;
    }

    /* generate canonical value if not already */
    if (!value->_canonical) {
        /* IPv4 mask + '/' + prefix */
        ret = malloc(INET_ADDRSTRLEN + 3);
        LY_CHECK_RET(!ret, NULL);

        /* convert back to string */
        if (!inet_ntop(AF_INET, &val->addr, ret, INET_ADDRSTRLEN)) {
            free(ret);
            return NULL;
        }

        /* add the prefix */
        sprintf(ret + strlen(ret), "/%" PRIu8, val->prefix);

        /* store it */
        if (lydict_insert_zc(ctx, ret, (const char **)&value->_canonical)) {
            LOGMEM(ctx);
            return NULL;
        }
    }

    /* use the cached canonical value */
    if (dynamic) {
        *dynamic = 0;
    }
    if (value_size_bits) {
        *value_size_bits = strlen(value->_canonical) * 8;
    }
    return value->_canonical;
}

static LY_ERR
lyplg_type_dup_ipv4_prefix(const struct ly_ctx *ctx, const struct lyd_value *original, struct lyd_value *dup)
{
    LY_ERR ret;
    struct lyd_value_ipv4_prefix *orig_val, *dup_val;

    memset(dup, 0, sizeof *dup);

    ret = lydict_insert(ctx, original->_canonical, 0, &dup->_canonical);
    LY_CHECK_GOTO(ret, error);

    LYPLG_TYPE_VAL_INLINE_PREPARE(dup, dup_val);
    LY_CHECK_ERR_GOTO(!dup_val, ret = LY_EMEM, error);

    LYD_VALUE_GET(original, orig_val);
    memcpy(dup_val, orig_val, sizeof *orig_val);

    dup->realtype = original->realtype;
    return LY_SUCCESS;

error:
    lyplg_type_free_ipv4_prefix(ctx, dup);
    return ret;
}

static void
lyplg_type_free_ipv4_prefix(const struct ly_ctx *ctx, struct lyd_value *value)
{
    struct lyd_value_ipv4_prefix *val;

    lydict_remove(ctx, value->_canonical);
    value->_canonical = NULL;
    LYD_VALUE_GET(value, val);
    LYPLG_TYPE_VAL_INLINE_DESTROY(val);
}

const struct lyplg_type_record plugins_ipv4_prefix[] = {
    {
        .module = "ietf-inet-types",
        .revision = "2013-07-15",
        .name = "ipv4-prefix",

        .plugin.id = "ly2 ipv4-prefix",
        .plugin.lyb_size = lyplg_type_lyb_size_ipv4_prefix,
        .plugin.store = lyplg_type_store_ipv4_prefix,
        .plugin.validate_value = NULL,
        .plugin.validate_tree = NULL,
        .plugin.compare = lyplg_type_compare_ipv4_prefix,
        .plugin.sort = lyplg_type_sort_ipv4_prefix,
        .plugin.print = lyplg_type_print_ipv4_prefix,
        .plugin.duplicate = lyplg_type_dup_ipv4_prefix,
        .plugin.free = lyplg_type_free_ipv4_prefix,
    },
    {0}
};