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


ngx_int_t ngx_ssl_init(ngx_log_t *log)
{
    SSL_library_init();
    SSL_load_error_strings();

    return NGX_OK;
}


ngx_int_t ngx_ssl_create_session(ngx_ssl_ctx_t *ssl_ctx, ngx_connection_t *c,
                                 ngx_uint_t flags)
{   
    ngx_ssl_t  *ssl;

    if (!(ssl = ngx_pcalloc(c->pool, sizeof(ngx_ssl_t)))) {
        return NGX_ERROR;
    }

    if (flags & NGX_SSL_BUFFER) {
        if (!(ssl->buf = ngx_create_temp_buf(c->pool, NGX_SSL_BUFSIZE))) {
            return NGX_ERROR;
        }
    }

    ssl->ssl = SSL_new(ssl_ctx);

    if (ssl->ssl == NULL) {
        ngx_ssl_error(NGX_LOG_ALERT, c->log, 0, "SSL_new() failed");
        return NGX_ERROR;
    }

    if (SSL_set_fd(ssl->ssl, c->fd) == 0) {
        ngx_ssl_error(NGX_LOG_ALERT, c->log, 0, "SSL_set_fd() failed");
        return NGX_ERROR;
    }

    SSL_set_accept_state(ssl->ssl);

    c->ssl = ssl;

    return NGX_OK;
}


ngx_int_t ngx_ssl_recv(ngx_connection_t *c, u_char *buf, size_t size)
{
    int         n, sslerr;
    ngx_err_t   err;
    char       *handshake;

    n = SSL_read(c->ssl->ssl, buf, size);

    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL_read: %d", n); 

    if (n > 0) {
        return n;
    }

    sslerr = SSL_get_error(c->ssl->ssl, n);

    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL_get_error: %d", sslerr);

    err = (sslerr == SSL_ERROR_SYSCALL) ? ngx_errno : 0;

    if (sslerr == SSL_ERROR_WANT_READ) {
        return NGX_AGAIN;
    }

#if 0
    if (sslerr == SSL_ERROR_WANT_WRITE) {
        return NGX_AGAIN;
    }
#endif

    if (!SSL_is_init_finished(c->ssl->ssl)) {
        handshake = "in SSL handshake";

    } else {
        handshake = "";
    }

    if (sslerr == SSL_ERROR_ZERO_RETURN || ERR_peek_error() == 0) {
        ngx_log_error(NGX_LOG_INFO, c->log, err,
                      "client closed connection%s", handshake);

        SSL_set_shutdown(c->ssl->ssl, SSL_RECEIVED_SHUTDOWN);

        return NGX_ERROR;
    }

    ngx_ssl_error(NGX_LOG_ALERT, c->log, err,
                  "SSL_read() failed%s", handshake);

    SSL_set_shutdown(c->ssl->ssl, SSL_RECEIVED_SHUTDOWN);

    return NGX_ERROR;
}


ngx_chain_t *ngx_ssl_send_chain(ngx_connection_t *c, ngx_chain_t *in,
                                off_t limit)
{
    int         n;
    ssize_t     send, size;
    ngx_buf_t  *buf;

    send = 0;

    buf = c->ssl->buf;

#if 0

    if (buf) {

        for ( ;; ) {

            for ( /* void */ ; in && buf->last < buf->end; in = in->next) {
                if (ngx_buf_special(in->buf)) {
                    continue;
                }

                size = in->buf->last - in->buf->pos;

                if (size > buf->end - buf->last) {
                    size = buf->end - buf->last;
                }

                ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
                               "SSL buf copy: %d", size);

                ngx_memcpy(buf->last, in->buf->pos, size);

                buf->last += size;
                in->buf->pos += size;
            }

            size = buf->last - buf->pos;

            if (send + size > limit) {
                size = limit - send;
            }

            ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
                           "SSL to write: %d", size);

            n = SSL_write(c->ssl->ssl, buf->pos, size);

            ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
                           "SSL_write: %d", n);

            if (n > 0) {
                buf->pos += n;
                send += n;

                if (n < size) {
                    break;
                }

                if (send < limit) {
                    if (buf->pos == buf->last) {
                        buf->pos = buf->start;
                        buf->last = buf->start;
                    }

                    if (in == NULL) {
                        break;
                    }

                    continue;
                }
            }

            n = SSL_get_error(c->ssl->ssl, n);

            ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
                           "SSL_get_error: %d", n);

            if (n == SSL_ERROR_WANT_WRITE) {
                break;
            }

#if 0
            if (n == SSL_ERROR_WANT_READ) {
                break;
            }
#endif

            ngx_ssl_error(NGX_LOG_ALERT, c->log, "SSL_write() failed");

            return NGX_CHAIN_ERROR;
        }

        if (in) {
            c->write->ready = 0;
            return in;
        }

        if (buf->pos == buf->last) {
            return NULL;

        } else {
            c->write->ready = 0;
            return NGX_CHAIN_AGAIN;            
        }
    }

#endif

    for (/* void */; in; in = in->next) {
        if (ngx_buf_special(in->buf)) {
            continue;
        }

        size = in->buf->last - in->buf->pos;

        if (send + size > limit) {
            size = limit - send;
        }

        ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
                       "SSL to write: %d", size);

        n = SSL_write(c->ssl->ssl, in->buf->pos, size);

        ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL_write: %d", n);

        if (n > 0) {
            in->buf->pos += n;
            send += n;

            if (n == size) {
                if (send < limit) {
                    continue;
                }

                return in;
            }

            c->write->ready = 0;
            return in;
        }

        n = SSL_get_error(c->ssl->ssl, n);

        ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL_get_error: %d", n);

        if (n == SSL_ERROR_WANT_WRITE) {
            c->write->ready = 0;
            return in;
        }

#if 0
        if (n == SSL_ERROR_WANT_READ) {
            return NGX_AGAIN;
        }
#endif

        ngx_ssl_error(NGX_LOG_ALERT, c->log, 0, "SSL_write() failed");

        return NGX_CHAIN_ERROR;
    }

    return in;
}


ngx_int_t ngx_ssl_shutdown(ngx_connection_t *c)
{
    int  n;
    ngx_uint_t  again;

#if 0
    if (c->read->timedout || c->write->timedout) {
        SSL_set_shutdown(c->ssl, SSL_RECEIVED_SHUTDOWN);
        SSL_set_shutdown(c->ssl, SSL_RECEIVED_SHUTDOWN|SSL_SENT_SHUTDOWN);
    }
#endif

#if 0
    SSL_set_shutdown(c->ssl->ssl, SSL_RECEIVED_SHUTDOWN);
#endif

    again = 0;

    for ( ;; ) {
        n = SSL_shutdown(c->ssl->ssl);

        ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL_shutdown: %d", n);

        if (n == 0) {
            again = 1;
            break;
        }

        if (n == 1) {
            SSL_free(c->ssl->ssl);
            c->ssl = NULL;
            return NGX_OK;
        }

        break;
    }

    if (!again) {
        n = SSL_get_error(c->ssl->ssl, n);

        ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL_get_error: %d", n);
    }

    if (again || n == SSL_ERROR_WANT_READ) {

        ngx_add_timer(c->read, 10000);

        if (ngx_handle_read_event(c->read, 0) == NGX_ERROR) {
            return NGX_ERROR;
        }

        return NGX_AGAIN;
    }

    if (n == SSL_ERROR_WANT_WRITE) {

        if (ngx_handle_write_event(c->write, 0) == NGX_ERROR) {
            return NGX_ERROR;
        }

        return NGX_AGAIN;
    }

    ngx_ssl_error(NGX_LOG_ALERT, c->log, 0, "SSL_shutdown() failed");

    return NGX_ERROR;
}


void ngx_ssl_error(ngx_uint_t level, ngx_log_t *log, ngx_err_t err,
                   char *fmt, ...)
{   
    int        len;
    char       errstr[NGX_MAX_CONF_ERRSTR];
    va_list    args;

    va_start(args, fmt);
    len = ngx_vsnprintf(errstr, sizeof(errstr) - 1, fmt, args);
    va_end(args);

    errstr[len++] = ' ';
    errstr[len++] = '(';
    errstr[len++] = 'S';
    errstr[len++] = 'S';
    errstr[len++] = 'L';
    errstr[len++] = ':';
    errstr[len++] = ' ';

    ERR_error_string_n(ERR_get_error(), errstr + len, sizeof(errstr) - len - 1);

    ngx_log_error(level, log, err, "%s)", errstr);
}