#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_quic_hkdf_expand(ngx_connection_t *c, const EVP_MD *digest, ngx_str_t *out,
    ngx_str_t *label, const uint8_t *prk, size_t prk_len)
{
    uint8_t  *p;
    size_t    info_len;
    uint8_t   info[20];

#if (NGX_DEBUG)
    u_char    buf[512];
    size_t    m;
#endif

    out->data = ngx_pnalloc(c->pool, out->len);
    if (out->data == NULL) {
        return NGX_ERROR;
    }

    info_len = 2 + 1 + label->len + 1;

    info[0] = 0;
    info[1] = out->len;
    info[2] = label->len;
    p = ngx_cpymem(&info[3], label->data, label->len);
    *p = '\0';

    if (ngx_hkdf_expand(out->data, out->len, digest,
                        prk, prk_len, info, info_len)
        != NGX_OK)
    {
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0,
                      "ngx_hkdf_expand(%V) failed", label);
        return NGX_ERROR;
    }

    if (c->log->log_level & NGX_LOG_DEBUG_EVENT) {
        m = ngx_hex_dump(buf, info, info_len) - buf;
        ngx_log_debug4(NGX_LOG_DEBUG_EVENT, c->log, 0,
                       "%V info: %*s, len: %uz", label, m, buf, info_len);

        m = ngx_hex_dump(buf, out->data, out->len) - buf;
        ngx_log_debug4(NGX_LOG_DEBUG_EVENT, c->log, 0,
                       "%V key: %*s, len: %uz", label, m, buf, out->len);
    }

    return NGX_OK;
}


ngx_int_t
ngx_hkdf_expand(u_char *out_key, size_t out_len, const EVP_MD *digest,
    const uint8_t *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;
}


ngx_int_t
ngx_quic_tls_open(ngx_connection_t *c, const EVP_CIPHER *cipher,
    ngx_quic_secret_t *s, ngx_str_t *out, u_char *nonce, ngx_str_t *in,
    ngx_str_t *ad)
{
    out->len = in->len - EVP_GCM_TLS_TAG_LEN;
    out->data = ngx_pnalloc(c->pool, out->len);
    if (out->data == NULL) {
        return NGX_ERROR;
    }

#ifdef OPENSSL_IS_BORINGSSLL
    EVP_AEAD_CTX *ctx;

    ctx = EVP_AEAD_CTX_new(cipher, s->key.data, s->key.len,
                           EVP_AEAD_DEFAULT_TAG_LENGTH);
    if (ctx == NULL) {
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_AEAD_CTX_new() failed");
        return NGX_ERROR;
    }

    if (EVP_AEAD_CTX_open(ctx, out->data, &out->len, out->len, nonce, s->iv.len,
                          in->data, in->len, ad->data, ad->len)
        != 1)
    {
        EVP_AEAD_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_AEAD_CTX_open() failed");
        return NGX_ERROR;
    }

    EVP_AEAD_CTX_free(ctx);
#else
    int              len;
    u_char          *tag;
    EVP_CIPHER_CTX  *ctx;

    ctx = EVP_CIPHER_CTX_new();
    if (ctx == NULL) {
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_CIPHER_CTX_new() failed");
        return NGX_ERROR;
    }

    if (EVP_DecryptInit_ex(ctx, cipher, NULL, NULL, NULL) != 1) {
        EVP_CIPHER_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_DecryptInit_ex() failed");
        return NGX_ERROR;
    }

    if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, s->iv.len, NULL)
        == 0)
    {
        EVP_CIPHER_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0,
                      "EVP_CIPHER_CTX_ctrl(EVP_CTRL_GCM_SET_IVLEN) failed");
        return NGX_ERROR;
    }

    if (EVP_DecryptInit_ex(ctx, NULL, NULL, s->key.data, nonce) != 1) {
        EVP_CIPHER_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_DecryptInit_ex() failed");
        return NGX_ERROR;
    }

    if (EVP_DecryptUpdate(ctx, NULL, &len, ad->data, ad->len) != 1) {
        EVP_CIPHER_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_DecryptUpdate() failed");
        return NGX_ERROR;
    }

    if (EVP_DecryptUpdate(ctx, out->data, &len, in->data,
                          in->len - EVP_GCM_TLS_TAG_LEN)
        != 1)
    {
        EVP_CIPHER_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_DecryptUpdate() failed");
        return NGX_ERROR;
    }

    out->len = len;
    tag = in->data + in->len - EVP_GCM_TLS_TAG_LEN;

    if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_TAG, EVP_GCM_TLS_TAG_LEN, tag)
        == 0)
    {
        EVP_CIPHER_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0,
                      "EVP_CIPHER_CTX_ctrl(EVP_CTRL_GCM_SET_TAG) failed");
        return NGX_ERROR;
    }

    if (EVP_DecryptFinal_ex(ctx, out->data + len, &len) <= 0) {
        EVP_CIPHER_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_DecryptFinal_ex failed");
        return NGX_ERROR;
    }

    out->len += len;

    EVP_CIPHER_CTX_free(ctx);
#endif

    return NGX_OK;
}


ngx_int_t
ngx_quic_tls_seal(ngx_connection_t *c, const EVP_CIPHER *cipher,
    ngx_quic_secret_t *s, ngx_str_t *out, u_char *nonce, ngx_str_t *in,
    ngx_str_t *ad)
{
    out->len = in->len + EVP_GCM_TLS_TAG_LEN;
    out->data = ngx_pnalloc(c->pool, out->len);
    if (out->data == NULL) {
        return NGX_ERROR;
    }

#ifdef OPENSSL_IS_BORINGSSLL
    EVP_AEAD_CTX *ctx;

    ctx = EVP_AEAD_CTX_new(cipher, s->key.data, s->key.len,
                           EVP_AEAD_DEFAULT_TAG_LENGTH);
    if (ctx == NULL) {
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_AEAD_CTX_new() failed");
        return NGX_ERROR;
    }

    if (EVP_AEAD_CTX_seal(ctx, out->data, &out->len, out->len, nonce, s->iv.len,
                          in->data, in->len, ad->data, ad->len)
        != 1)
    {
        EVP_AEAD_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_AEAD_CTX_seal() failed");
        return NGX_ERROR;
    }

    EVP_AEAD_CTX_free(ctx);
#else
    int              len;
    EVP_CIPHER_CTX  *ctx;

    ctx = EVP_CIPHER_CTX_new();
    if (ctx == NULL) {
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_CIPHER_CTX_new() failed");
        return NGX_ERROR;
    }

    if (EVP_EncryptInit_ex(ctx, cipher, NULL, NULL, NULL) != 1) {
        EVP_CIPHER_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_EncryptInit_ex() failed");
        return NGX_ERROR;
    }

    if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, s->iv.len, NULL)
        == 0)
    {
        EVP_CIPHER_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0,
                      "EVP_CIPHER_CTX_ctrl(EVP_CTRL_GCM_SET_IVLEN) failed");
        return NGX_ERROR;
    }

    if (EVP_EncryptInit_ex(ctx, NULL, NULL, s->key.data, nonce) != 1) {
        EVP_CIPHER_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_EncryptInit_ex() failed");
        return NGX_ERROR;
    }

    if (EVP_EncryptUpdate(ctx, NULL, &len, ad->data, ad->len) != 1) {
        EVP_CIPHER_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_EncryptUpdate() failed");
        return NGX_ERROR;
    }

    if (EVP_EncryptUpdate(ctx, out->data, &len, in->data, in->len) != 1) {
        EVP_CIPHER_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_EncryptUpdate() failed");
        return NGX_ERROR;
    }

    out->len = len;

    if (EVP_EncryptFinal_ex(ctx, out->data + out->len, &len) <= 0) {
        EVP_CIPHER_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_EncryptFinal_ex failed");
        return NGX_ERROR;
    }

    out->len += len;

    if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_GET_TAG, EVP_GCM_TLS_TAG_LEN,
                            out->data + in->len)
        == 0)
    {
        EVP_CIPHER_CTX_free(ctx);
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0,
                      "EVP_CIPHER_CTX_ctrl(EVP_CTRL_GCM_GET_TAG) failed");
        return NGX_ERROR;
    }

    EVP_CIPHER_CTX_free(ctx);

    out->len += EVP_GCM_TLS_TAG_LEN;
#endif

    return NGX_OK;
}


ngx_int_t
ngx_quic_tls_hp(ngx_connection_t *c, const EVP_CIPHER *cipher,
    ngx_quic_secret_t *s, u_char *out, u_char *in)
{
    int              outlen;
    EVP_CIPHER_CTX  *ctx;

    ctx = EVP_CIPHER_CTX_new();
    if (ctx == NULL) {
        return NGX_ERROR;
    }

    if (EVP_EncryptInit_ex(ctx, cipher, NULL, s->hp.data, NULL) != 1) {
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_EncryptInit_ex() failed");
        goto failed;
    }

    if (!EVP_EncryptUpdate(ctx, out, &outlen, in, 16)) {
        ngx_ssl_error(NGX_LOG_INFO, c->log, 0, "EVP_EncryptUpdate() failed");
        goto failed;
    }

    EVP_CIPHER_CTX_free(ctx);

    return NGX_OK;

failed:

    EVP_CIPHER_CTX_free(ctx);

    return NGX_ERROR;
}