int WPACKET_reserve_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
{
    assert(pkt->subs != NULL && len != 0);
    if (pkt->subs == NULL || len == 0)
        return 0;
    if (pkt->maxsize - pkt->written < len)
        return 0;
    if (pkt->buf->length - pkt->written < len) {
        size_t newlen;
        size_t reflen;
        reflen = (len > pkt->buf->length) ? len : pkt->buf->length;
        if (reflen > SIZE_MAX / 2) {
            newlen = SIZE_MAX;
        } else {
            newlen = reflen * 2;
            if (newlen < DEFAULT_BUF_SIZE)
                newlen = DEFAULT_BUF_SIZE;
        }
        if (BUF_MEM_grow(pkt->buf, newlen) == 0)
            return 0;
    }
    *allocbytes = (unsigned char *)pkt->buf->data + pkt->curr;
    return 1;
}
['int tls_construct_client_hello(SSL *s, WPACKET *pkt)\n{\n    unsigned char *p;\n    size_t sess_id_len;\n    int i, protverr;\n    int al = SSL_AD_HANDSHAKE_FAILURE;\n#ifndef OPENSSL_NO_COMP\n    SSL_COMP *comp;\n#endif\n    SSL_SESSION *sess = s->session;\n    if (!WPACKET_set_max_size(pkt, SSL3_RT_MAX_PLAIN_LENGTH)) {\n        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);\n        return 0;\n    }\n    protverr = ssl_set_client_hello_version(s);\n    if (protverr != 0) {\n        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, protverr);\n        return 0;\n    }\n    if ((sess == NULL) || !ssl_version_supported(s, sess->ssl_version) ||\n        (!sess->session_id_length && !sess->tlsext_tick) ||\n        (sess->not_resumable)) {\n        if (!ssl_get_new_session(s, 0))\n            return 0;\n    }\n    p = s->s3->client_random;\n    if (SSL_IS_DTLS(s)) {\n        size_t idx;\n        i = 1;\n        for (idx = 0; idx < sizeof(s->s3->client_random); idx++) {\n            if (p[idx]) {\n                i = 0;\n                break;\n            }\n        }\n    } else\n        i = 1;\n    if (i && ssl_fill_hello_random(s, 0, p, sizeof(s->s3->client_random)) <= 0)\n        return 0;\n    if (!WPACKET_put_bytes_u16(pkt, s->client_version)\n            || !WPACKET_memcpy(pkt, s->s3->client_random, SSL3_RANDOM_SIZE)) {\n        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);\n        return 0;\n    }\n    if (s->new_session)\n        sess_id_len = 0;\n    else\n        sess_id_len = s->session->session_id_length;\n    if (sess_id_len > sizeof(s->session->session_id)\n            || !WPACKET_start_sub_packet_u8(pkt)\n            || (sess_id_len != 0 && !WPACKET_memcpy(pkt, s->session->session_id,\n                                                    sess_id_len))\n            || !WPACKET_close(pkt)) {\n        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);\n        return 0;\n    }\n    if (SSL_IS_DTLS(s)) {\n        if (s->d1->cookie_len > sizeof(s->d1->cookie)\n                || !WPACKET_sub_memcpy_u8(pkt, s->d1->cookie,\n                                          s->d1->cookie_len)) {\n            SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);\n            return 0;\n        }\n    }\n    if (!WPACKET_start_sub_packet_u16(pkt)) {\n        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);\n        return 0;\n    }\n    if (!ssl_cipher_list_to_bytes(s, SSL_get_ciphers(s), pkt))\n        return 0;\n    if (!WPACKET_close(pkt)) {\n        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);\n        return 0;\n    }\n    if (!WPACKET_start_sub_packet_u8(pkt)) {\n        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);\n        return 0;\n    }\n#ifndef OPENSSL_NO_COMP\n    if (ssl_allow_compression(s) && s->ctx->comp_methods) {\n        int compnum = sk_SSL_COMP_num(s->ctx->comp_methods);\n        for (i = 0; i < compnum; i++) {\n            comp = sk_SSL_COMP_value(s->ctx->comp_methods, i);\n            if (!WPACKET_put_bytes_u8(pkt, comp->id)) {\n                SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);\n                return 0;\n            }\n        }\n    }\n#endif\n    if (!WPACKET_put_bytes_u8(pkt, 0) || !WPACKET_close(pkt)) {\n        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);\n        return 0;\n    }\n    if (ssl_prepare_clienthello_tlsext(s) <= 0) {\n        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, SSL_R_CLIENTHELLO_TLSEXT);\n        return 0;\n    }\n    if (!WPACKET_start_sub_packet_u16(pkt)\n            || !WPACKET_set_flags(pkt, WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH)\n            || !ssl_add_clienthello_tlsext(s, pkt, &al)\n            || !WPACKET_close(pkt)) {\n        ssl3_send_alert(s, SSL3_AL_FATAL, al);\n        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);\n        return 0;\n    }\n    return 1;\n}', 'int WPACKET_start_sub_packet_len__(WPACKET *pkt, size_t lenbytes)\n{\n    WPACKET_SUB *sub;\n    unsigned char *lenchars;\n    assert(pkt->subs != NULL);\n    if (pkt->subs == NULL)\n        return 0;\n    sub = OPENSSL_zalloc(sizeof(*sub));\n    if (sub == NULL)\n        return 0;\n    sub->parent = pkt->subs;\n    pkt->subs = sub;\n    sub->pwritten = pkt->written + lenbytes;\n    sub->lenbytes = lenbytes;\n    if (lenbytes == 0) {\n        sub->packet_len = 0;\n        return 1;\n    }\n    if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars))\n        return 0;\n    sub->packet_len = lenchars - (unsigned char *)pkt->buf->data;\n    return 1;\n}', 'int WPACKET_memcpy(WPACKET *pkt, const void *src, size_t len)\n{\n    unsigned char *dest;\n    if (len == 0)\n        return 1;\n    if (!WPACKET_allocate_bytes(pkt, len, &dest))\n        return 0;\n    memcpy(dest, src, len);\n    return 1;\n}', 'int WPACKET_allocate_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)\n{\n    if (!WPACKET_reserve_bytes(pkt, len, allocbytes))\n        return 0;\n    pkt->written += len;\n    pkt->curr += len;\n    return 1;\n}', 'int WPACKET_reserve_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)\n{\n    assert(pkt->subs != NULL && len != 0);\n    if (pkt->subs == NULL || len == 0)\n        return 0;\n    if (pkt->maxsize - pkt->written < len)\n        return 0;\n    if (pkt->buf->length - pkt->written < len) {\n        size_t newlen;\n        size_t reflen;\n        reflen = (len > pkt->buf->length) ? len : pkt->buf->length;\n        if (reflen > SIZE_MAX / 2) {\n            newlen = SIZE_MAX;\n        } else {\n            newlen = reflen * 2;\n            if (newlen < DEFAULT_BUF_SIZE)\n                newlen = DEFAULT_BUF_SIZE;\n        }\n        if (BUF_MEM_grow(pkt->buf, newlen) == 0)\n            return 0;\n    }\n    *allocbytes = (unsigned char *)pkt->buf->data + pkt->curr;\n    return 1;\n}']