telnet.c

/*
 *   VDETELWEB: VDE telnet, SSH and WEB interface
 *
 *   telnet.c: telnet module
 *
 *   Copyright 2005,2007 Renzo Davoli University of Bologna - Italy
 *   from lwip to libioth by Gabriele Genovese 2023
 *
 *   This program is free software: you can redistribute it and/or modify it under
 *   the terms of the GNU General Public License as published by the Free Software
 *   Foundation, either version 3 of the License, or (at your option) any later version.
 *   
 *   This program is distributed in the hope that it will be useful, but WITHOUT ANY
 *   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 *   PARTICULAR PURPOSE. See the GNU General Public License for more details.
 * 
 *   You should have received a copy of the GNU General Public License along with this
 *   program. If not, see <https://www.gnu.org/licenses/>.
 *
 *   $Id$
 *
 */
#include "vdetelweb.h"
#include <arpa/inet.h>
#include <libvdehist.h>
#include <syslog.h>

#define TELNET_PORT 23
#define DEVTELNET_PORT 2323 // use this in development

void telnetdata(int fn, int fd, int vdefd) {
  (void)fd;
  (void)vdefd;
  struct vdehiststat *vdehst = status[fn];
  if (vdehist_term_to_mgmt(vdehst) != 0) {
    int termfd = vdehist_gettermfd(vdehst);
    int mgmtfd = vdehist_getmgmtfd(vdehst);
    delpfd(pfdsearch(termfd));
    ioth_close(termfd);
    if (mgmtfd >= 0) {
      delpfd(mgmtfd);
      close(mgmtfd);
    }
    vdehist_free(vdehst);
  }
}

void telnet_vdedata(int fn, int fd, int vdefd) {
  (void)fd;
  (void)vdefd;
  struct vdehiststat *vdehst = status[fn];
  vdehist_mgmt_to_term(vdehst);
}

char *telnet_logincmd(char *cmd, int len, struct vdehiststat *st) {
  int histstatus = vdehist_getstatus(st);
  int termfd = vdehist_gettermfd(st);
  switch (histstatus) {
  case HIST_NOCMD:
    while (cmd[len - 1] == '\n')
      cmd[--len] = 0;
    if (!is_usr_correct(cmd))
      ioth_write(termfd, "Invalid user\r\n\r\nLogin: ", 24);
    else {
      ioth_write(termfd, "Password: ", 11);
      vdehist_setstatus(st, HIST_PASSWDFLAG);
    }
    break;
  case HIST_PASSWDFLAG:
  case HIST_PASSWDFLAG + 1:
  case HIST_PASSWDFLAG + 2:
    while (cmd[len - 1] == '\n')
      cmd[--len] = 0;
    if (!is_passwd_correct(cmd)) {
      histstatus++;
      vdehist_setstatus(st, histstatus);
      if (histstatus < (HIST_PASSWDFLAG + 3))
        ioth_write(termfd, "\r\nlogin incorrect\r\n\r\nPassword: ", 32);
      else
        return "logout";
    } else {
      int newfn, flags, mgmtfd;
      vdehist_setstatus(st, HIST_COMMAND);

      if ((mgmtfd = open_extra_vde_mgmt()) < 0)
        return "logout";

      vdehist_setmgmtfd(st, mgmtfd);
      flags = fcntl(mgmtfd, F_GETFL);
      flags |= O_NONBLOCK;
      fcntl(mgmtfd, F_SETFL, flags);
      newfn = addpfd(mgmtfd, telnet_vdedata);
      status[newfn] = st;
      ioth_write(termfd, "\r\n", 2);
      ioth_write(termfd, prompt, strlen(prompt));
    }
  }
  return NULL;
}

void telnetaccept(int fn, int fd, int vdefd) {
  (void)fn;
  (void)vdefd;
  struct sockaddr_in cli_addr;
  int newsockfd, newfn;
  uint32_t cli_len = sizeof(cli_addr);

  if ((newsockfd = ioth_accept(fd, (struct sockaddr *)&cli_addr, &cli_len)) < 0)
    printlog(LOG_ERR, "telnet accept err: %s", strerror(errno));

  newfn = addpfd(newsockfd, telnetdata);
  status[newfn] = vdehist_new(newsockfd, -1);
  ioth_write(newsockfd, banner, strlen(banner));
  ioth_write(newsockfd, "\r\nLogin: ", 9);
}

void telnet_init(struct ioth *iothstack) {
  int sockfd;
  struct sockaddr_in serv_addr;
  vdehist_termread = ioth_read;
  vdehist_termwrite = ioth_write;
  vdehist_logincmd = telnet_logincmd;

  if ((sockfd = ioth_msocket(iothstack, AF_INET, SOCK_STREAM, 0)) == 0)
    printlog(LOG_ERR, "telnet socket err: %s", strerror(errno));

  bzero((char *)&serv_addr, sizeof(serv_addr));
  serv_addr.sin_family = AF_INET;
  serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
  serv_addr.sin_port = htons(TELNET_PORT); // todo: change the port in prod/dev

  if (ioth_bind(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)
    printlog(LOG_ERR, "telnet bind err: %s", strerror(errno));

  ioth_listen(sockfd, 5);
  addpfd(sockfd, telnetaccept);
}