#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>


uint64_t
ngx_quic_parse_int(u_char **pos)
{
    u_char      *p;
    uint64_t     value;
    ngx_uint_t   len;

    p = *pos;
    len = 1 << ((*p & 0xc0) >> 6);
    value = *p++ & 0x3f;

    while (--len) {
        value = (value << 8) + *p++;
    }

    *pos = p;
    return value;
}


void
ngx_quic_build_int(u_char **pos, uint64_t value)
{
    u_char      *p;
    ngx_uint_t   len;//, len2;

    p = *pos;
    len = 0;

    while (value >> ((1 << len) * 8 - 2)) {
        len++;
    }

    *p = len << 6;

//    len2 =
    len = (1 << len);
    len--;
    *p |= value >> (len * 8);
    p++;

    while (len) {
        *p++ = value >> ((len-- - 1) * 8);
    }

    *pos = p;
//    return len2;
}


uint64_t
ngx_quic_parse_pn(u_char **pos, ngx_int_t len, u_char *mask)
{
    u_char      *p;
    uint64_t     value;

    p = *pos;
    value = *p++ ^ *mask++;

    while (--len) {
        value = (value << 8) + (*p++ ^ *mask++);
    }

    *pos = p;
    return value;
}


ngx_int_t
ngx_hkdf_extract(u_char *out_key, size_t *out_len, const EVP_MD *digest,
    const u_char *secret, size_t secret_len, const u_char *salt,
    size_t salt_len)
{
#ifdef OPENSSL_IS_BORINGSSL
    if (HKDF_extract(out_key, out_len, digest, secret, secret_len, salt,
                     salt_len)
        == 0)
    {
        return NGX_ERROR;
    }
#else

    EVP_PKEY_CTX  *pctx;

    pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);

    if (EVP_PKEY_derive_init(pctx) <= 0) {
        return NGX_ERROR;
    }

    if (EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY) <= 0) {
        return NGX_ERROR;
    }

    if (EVP_PKEY_CTX_set_hkdf_md(pctx, digest) <= 0) {
        return NGX_ERROR;
    }

    if (EVP_PKEY_CTX_set1_hkdf_key(pctx, secret, secret_len) <= 0) {
        return NGX_ERROR;
    }

    if (EVP_PKEY_CTX_set1_hkdf_salt(pctx, salt, salt_len) <= 0) {
        return NGX_ERROR;
    }

    if (EVP_PKEY_derive(pctx, out_key, out_len) <= 0) {
        return NGX_ERROR;
    }

#endif

    return NGX_OK;
}


ngx_int_t
ngx_hkdf_expand(u_char *out_key, size_t out_len, const EVP_MD *digest,
    const u_char *prk, size_t prk_len, const u_char *info, size_t info_len)
{
#ifdef OPENSSL_IS_BORINGSSL
    if (HKDF_expand(out_key, out_len, digest, prk, prk_len, info, info_len)
        == 0)
    {
        return NGX_ERROR;
    }
#else

    EVP_PKEY_CTX  *pctx;

    pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);

    if (EVP_PKEY_derive_init(pctx) <= 0) {
        return NGX_ERROR;
    }

    if (EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY) <= 0) {
        return NGX_ERROR;
    }

    if (EVP_PKEY_CTX_set_hkdf_md(pctx, digest) <= 0) {
        return NGX_ERROR;
    }

    if (EVP_PKEY_CTX_set1_hkdf_key(pctx, prk, prk_len) <= 0) {
        return NGX_ERROR;
    }

    if (EVP_PKEY_CTX_add1_hkdf_info(pctx, info, info_len) <= 0) {
        return NGX_ERROR;
    }

    if (EVP_PKEY_derive(pctx, out_key, &out_len) <= 0) {
        return NGX_ERROR;
    }

#endif

    return NGX_OK;
}