329 lines
7.1 KiB
C
329 lines
7.1 KiB
C
/*
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* This file is distributed as part of the SkySQL Gateway. It is free
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* software: you can redistribute it and/or modify it under the terms of the
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* GNU General Public License as published by the Free Software Foundation,
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* version 2.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Copyright SkySQL Ab 2013
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <dcb.h>
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#include <buffer.h>
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#include <service.h>
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#include <session.h>
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#include <sys/ioctl.h>
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#include <errno.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <router.h>
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#include <poll.h>
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#include <atomic.h>
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#include <gw.h>
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/**
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* @file telnetd.c - telnet daemon protocol module
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*
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* The telnetd protocol module is intended as a mechanism to allow connections
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* into the gateway for the purpsoe of accessing debugging information within
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* the gateway rather than a protocol to be used to send queries to backend
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* databases.
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*
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* In the first instance it is intended to allow a debug connection to access
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* internal data structures, however it may also be used to manage the
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* configuration of the gateway.
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*
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* @verbatim
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* Revision History
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* Date Who Description
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* 17/06/2013 Mark Riddoch Initial version
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*
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* @endverbatim
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*/
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#define TELNET_IAC 255
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static char *version_str = "V1.0.0";
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static int telnetd_read_event(DCB* dcb);
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static int telnetd_write_event(DCB *dcb);
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static int telnetd_write(DCB *dcb, GWBUF *queue);
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static int telnetd_error(DCB *dcb);
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static int telnetd_hangup(DCB *dcb);
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static int telnetd_accept(DCB *dcb);
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static int telnetd_close(DCB *dcb);
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static int telnetd_listen(DCB *dcb, char *config);
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/**
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* The "module object" for the telnetd protocol module.
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*/
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static GWPROTOCOL MyObject = {
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telnetd_read_event, /**< Read - EPOLLIN handler */
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telnetd_write, /**< Write - data from gateway */
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telnetd_write_event, /**< WriteReady - EPOLLOUT handler */
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telnetd_error, /**< Error - EPOLLERR handler */
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telnetd_hangup, /**< HangUp - EPOLLHUP handler */
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telnetd_accept, /**< Accept */
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NULL, /**< Connect */
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telnetd_close, /**< Close */
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telnetd_listen /**< Create a listener */
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};
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static void
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telnetd_command(DCB *, char *cmd);
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/**
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* Implementation of the mandatory version entry point
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*
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* @return version string of the module
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*/
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char *
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version()
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{
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return version_str;
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}
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/**
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* The module initialisation routine, called when the module
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* is first loaded.
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*/
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void
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ModuleInit()
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{
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fprintf(stderr, "Initialise Telnetd Protocol module.\n");
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}
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/**
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* The module entry point routine. It is this routine that
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* must populate the structure that is referred to as the
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* "module object", this is a structure with the set of
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* external entry points for this module.
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*
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* @return The module object
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*/
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GWPROTOCOL *
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GetModuleObject()
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{
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return &MyObject;
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}
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/**
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* Read event for EPOLLIN on the telnetd protocol module.
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*
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* @param dcb The descriptor control block
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* @return
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*/
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static int
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telnetd_read_event(DCB* dcb)
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{
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int n;
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GWBUF *head = NULL;
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SESSION *session = dcb->session;
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ROUTER_OBJECT *router = session->service->router;
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ROUTER *router_instance = session->service->router_instance;
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void *rsession = session->router_session;
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if ((n = dcb_read(dcb, &head)) != -1)
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{
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dcb->state = DCB_STATE_PROCESSING;
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if (head)
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{
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char *ptr = GWBUF_DATA(head);
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ptr = GWBUF_DATA(head);
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if (*ptr == TELNET_IAC)
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{
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telnetd_command(dcb, ptr + 1);
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GWBUF_CONSUME(head, 2);
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}
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router->routeQuery(router_instance, rsession, head);
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}
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}
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dcb->state = DCB_STATE_POLLING;
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return n;
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}
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/**
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* EPOLLOUT handler for the telnetd protocol module.
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*
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* @param dcb The descriptor control block
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* @return
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*/
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static int
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telnetd_write_event(DCB *dcb)
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{
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return dcb_drain_writeq(dcb);
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}
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/**
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* Write routine for the telnetd protocol module.
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*
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* Writes the content of the buffer queue to the socket
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* observing the non-blocking principles of the gateway.
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*
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* @param dcb Descriptor Control Block for the socket
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* @param queue Linked list of buffes to write
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*/
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static int
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telnetd_write(DCB *dcb, GWBUF *queue)
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{
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return dcb_write(dcb, queue);
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}
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/**
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* Handler for the EPOLLERR event.
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*
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* @param dcb The descriptor control block
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*/
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static int
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telnetd_error(DCB *dcb)
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{
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return 0;
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}
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/**
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* Handler for the EPOLLHUP event.
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*
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* @param dcb The descriptor control block
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*/
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static int
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telnetd_hangup(DCB *dcb)
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{
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return 0;
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}
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/**
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* Handler for the EPOLLIN event when the DCB refers to the listening
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* socket for the protocol.
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*
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* @param dcb The descriptor control block
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*/
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static int
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telnetd_accept(DCB *dcb)
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{
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int n_connect = 0;
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while (1)
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{
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int so;
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struct sockaddr_in addr;
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socklen_t addrlen;
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DCB *client;
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if ((so = accept(dcb->fd, (struct sockaddr *)&addr, &addrlen)) == -1)
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return n_connect;
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else
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{
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atomic_add(&dcb->stats.n_accepts, 1);
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client = dcb_alloc();
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client->fd = so;
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client->remote = strdup(inet_ntoa(addr.sin_addr));
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memcpy(&client->func, &MyObject, sizeof(GWPROTOCOL));
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client->session = session_alloc(dcb->session->service, client);
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client->state = DCB_STATE_IDLE;
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if (poll_add_dcb(client) == -1)
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{
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return n_connect;
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}
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n_connect++;
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dcb_printf(client, "Gateway> ");
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client->state = DCB_STATE_POLLING;
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}
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}
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return n_connect;
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}
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/**
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* The close handler for the descriptor. Called by the gateway to
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* explicitly close a connection.
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*
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* @param dcb The descriptor control block
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*/
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static int
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telnetd_close(DCB *dcb)
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{
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dcb_close(dcb);
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return 0;
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}
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/**
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* Telnet daemon listener entry point
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*
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* @param listener The Listener DCB
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* @param config Configuration (ip:port)
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*/
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static int
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telnetd_listen(DCB *listener, char *config)
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{
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struct sockaddr_in addr;
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char *port;
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int one = 1;
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short pnum;
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memcpy(&listener->func, &MyObject, sizeof(GWPROTOCOL));
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port = strrchr(config, ':');
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if (port)
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port++;
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else
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port = "4442";
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addr.sin_family = AF_INET;
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addr.sin_addr.s_addr = htonl(INADDR_ANY);
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pnum = atoi(port);
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addr.sin_port = htons(pnum);
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if ((listener->fd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
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{
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return 0;
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}
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// socket options
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setsockopt(listener->fd, SOL_SOCKET, SO_REUSEADDR, (char *)&one, sizeof(one));
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// set NONBLOCKING mode
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setnonblocking(listener->fd);
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// bind address and port
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if (bind(listener->fd, (struct sockaddr *)&addr, sizeof(addr)) < 0)
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{
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return 0;
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}
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listener->state = DCB_STATE_LISTENING;
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listen(listener->fd, SOMAXCONN);
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if (poll_add_dcb(listener) == -1)
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{
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return 0;
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}
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return 1;
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}
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/**
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* Telnet command implementation
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*
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* Called for each command in the telnet stream.
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*
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* Currently we do no command execution
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*
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* @param dcb The client DCB
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* @param cmd The command stream
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*/
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static void
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telnetd_command(DCB *dcb, char *cmd)
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{
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}
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