message-func.c

/* message-func.c -- Functions for working with SSH messages.
 *
 * Copyright (C) 2013, 2014 Artyom V. Poptsov <poptsov.artyom@gmail.com>
 *
 * This file is part of Guile-SSH
 *
 * Guile-SSH 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.
 *
 * Guile-SSH 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 Guile-SSH.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>

#include <libguile.h>
#include <libssh/libssh.h>
#include <libssh/server.h>

#include "common.h"
#include "channel-type.h"
#include "message-type.h"
#include "message-func.h"
#include "key-type.h"
#include "error.h"
#include "log.h"


/* Procedures that are used for replying on requests. */

SCM_DEFINE (guile_ssh_message_reply_default,
            "message-reply-default", 1, 0, 0,
            (SCM msg),
            "\
Reduced version of the reply default that only reply with \
SSH_MSG_UNIMPLEMENTED.\n\
\n\
Return value is undefined.\
")
#define FUNC_NAME s_guile_ssh_message_reply_default
{
  gssh_message_t* msg_data = gssh_message_from_scm (msg);
  int res = ssh_message_reply_default (msg_data->message);
  _gssh_log_debug_format(FUNC_NAME, msg, "result: %d", res);
  if (res != SSH_OK)
    guile_ssh_error1 (FUNC_NAME, "Unable to reply", msg);
  return SCM_UNDEFINED;
}
#undef FUNC_NAME

SCM_DEFINE (guile_ssh_message_service_reply_success,
            "message-service-reply-success", 1, 0, 0,
            (SCM msg),
            "\
Reply with \"success\" status on the service-request message MSG.\n\
Return value is undefined.\
")
#define FUNC_NAME s_guile_ssh_message_service_reply_success
{
  gssh_message_t* msg_data = gssh_message_from_scm (msg);
  int res = ssh_message_service_reply_success (msg_data->message);
  _gssh_log_debug_format(FUNC_NAME, msg, "result: %d", res);
  if (res != SSH_OK)
    guile_ssh_error1 (FUNC_NAME, "Unable to reply", msg);
  return SCM_UNDEFINED;
}
#undef FUNC_NAME

SCM_DEFINE (guile_ssh_message_auth_reply_success,
            "message-auth-reply-success", 2, 0, 0,
            (SCM msg, SCM partial_p),
            "\
Reply with \"success\" on the auth-request message MSG.\n\
Return value is undefined.\
")
#define FUNC_NAME s_guile_ssh_message_auth_reply_success
{
  gssh_message_t* msg_data = gssh_message_from_scm (msg);
  int c_partial_p = scm_to_bool (partial_p);
  int res = ssh_message_auth_reply_success (msg_data->message, c_partial_p);
  _gssh_log_debug_format(FUNC_NAME, msg, "result: %d", res);
  if (res != SSH_OK)
    {
      guile_ssh_error1 (FUNC_NAME, "Unable to reply",
                        scm_list_2 (msg, partial_p));
    }
  return SCM_UNDEFINED;
}
#undef FUNC_NAME

SCM_DEFINE (guile_ssh_message_auth_reply_public_key_ok,
            "message-auth-reply-public-key-ok", 1, 0, 0,
            (SCM msg),
            "\
Reply OK on the public key auth-request message MSG.\n\
Return value is undefined.\
")
#define FUNC_NAME s_guile_ssh_message_auth_reply_public_key_ok
{
  gssh_message_t* msg_data = gssh_message_from_scm (msg);
  int res = ssh_message_auth_reply_pk_ok_simple (msg_data->message);
  _gssh_log_debug_format(FUNC_NAME, msg, "result: %d", res);
  if (res != SSH_OK)
    guile_ssh_error1 (FUNC_NAME, "Unable to reply", msg);
  return SCM_UNDEFINED;
}
#undef FUNC_NAME

SCM_DEFINE (guile_ssh_message_channel_request_reply_success,
            "message-channel-request-reply-success", 1, 0, 0,
            (SCM msg),
            "\
TODO: Add description.\n\
Return value is undefined.\
")
#define FUNC_NAME s_guile_ssh_message_channel_request_reply_success
{
  gssh_message_t* msg_data = gssh_message_from_scm (msg);
  int res = ssh_message_channel_request_reply_success (msg_data->message);
  _gssh_log_debug_format(FUNC_NAME, msg, "result: %d", res);
  if (res != SSH_OK)
    guile_ssh_error1 (FUNC_NAME, "Unable to reply", msg);
  return SCM_UNDEFINED;
}
#undef FUNC_NAME

SCM_DEFINE (guile_ssh_message_channel_request_open_reply_accept,
            "message-channel-request-open-reply-accept", 1, 0, 0,
            (SCM msg),
            "\
Accept open-channel request.\n\
Return a new SSH channel.\
")
{
  gssh_message_t* msg_data = gssh_message_from_scm (msg);
  ssh_channel ch;

  ch = ssh_message_channel_request_open_reply_accept (msg_data->message);
  if (! ch)
    return SCM_BOOL_F;

  SCM channel = ssh_channel_to_scm (ch, msg_data->session,
                                    SCM_RDNG | SCM_WRTNG);

  SCM_SET_CELL_TYPE (channel, SCM_CELL_TYPE (channel) | SCM_OPN);

  return channel;
}

SCM_DEFINE (gssh_message_global_request_reply_success,
            "message-global-request-reply-success", 2, 0, 0,
            (SCM msg, SCM bound_port), "")
#define FUNC_NAME s_gssh_message_global_request_reply_success
{
  gssh_message_t* md = gssh_message_from_scm (msg);
  int res;

  SCM_ASSERT (scm_is_unsigned_integer (bound_port, 0, UINT16_MAX), bound_port,
              SCM_ARG2, FUNC_NAME);

  res = ssh_message_global_request_reply_success (md->message,
                                                  scm_to_uint16 (bound_port));
  _gssh_log_debug_format(FUNC_NAME, scm_list_2 (msg, bound_port),
                         "result: %d", res);
  if (res != SSH_OK)
    {
      guile_ssh_error1 (FUNC_NAME, "Unable to reply",
                        scm_list_2 (msg, bound_port));
    }

  return SCM_UNDEFINED;
}
#undef FUNC_NAME



static gssh_symbol_t req_types[] = {
  { "request-auth",         SSH_REQUEST_AUTH         },
  { "request-channel-open", SSH_REQUEST_CHANNEL_OPEN },
  { "request-channel",      SSH_REQUEST_CHANNEL      },
  { "request-service",      SSH_REQUEST_SERVICE      },
  { "request-global",       SSH_REQUEST_GLOBAL       },
  { NULL,           -1                               }
};

static gssh_symbol_t req_auth_subtypes[] = {
  { "auth-method-unknown",     SSH_AUTH_METHOD_UNKNOWN     },
  { "auth-method-none",        SSH_AUTH_METHOD_NONE        },
  { "auth-method-password",    SSH_AUTH_METHOD_PASSWORD    },
  { "auth-method-publickey",   SSH_AUTH_METHOD_PUBLICKEY   },
  { "auth-method-hostbased",   SSH_AUTH_METHOD_HOSTBASED   },
  { "auth-method-interactive", SSH_AUTH_METHOD_INTERACTIVE },
  { NULL,                      -1                          }
};

static gssh_symbol_t req_channel_subtypes[] = {
  { "channel-request-unknown",       SSH_CHANNEL_REQUEST_UNKNOWN       },
  { "channel-request-pty",           SSH_CHANNEL_REQUEST_PTY           },
  { "channel-request-exec",          SSH_CHANNEL_REQUEST_EXEC          },
  { "channel-request-shell",         SSH_CHANNEL_REQUEST_SHELL         },
  { "channel-request-env",           SSH_CHANNEL_REQUEST_ENV           },
  { "channel-request-subsystem",     SSH_CHANNEL_REQUEST_SUBSYSTEM     },
  { "channel-request-window-change", SSH_CHANNEL_REQUEST_WINDOW_CHANGE },
  { NULL,                            -1                                }
};

static gssh_symbol_t req_channel_open_subtypes[] = {
  { "channel-unknown",         SSH_CHANNEL_UNKNOWN         },
  { "channel-session",         SSH_CHANNEL_SESSION         },
  { "channel-direct-tcpip",    SSH_CHANNEL_DIRECT_TCPIP    },
  { "channel-forwarded-tcpip", SSH_CHANNEL_FORWARDED_TCPIP },
  { "channel-x11",             SSH_CHANNEL_X11             },
  { NULL,                      -1                          }
};

static gssh_symbol_t req_global_subtypes[] = {
  { "global-request-unknown",              SSH_GLOBAL_REQUEST_UNKNOWN              },
  { "global-request-tcpip-forward",        SSH_GLOBAL_REQUEST_TCPIP_FORWARD        },
  { "global-request-cancel-tcpip-forward", SSH_GLOBAL_REQUEST_CANCEL_TCPIP_FORWARD },
  { NULL,                                  -1                                      }
};

static gssh_symbol_t pubkey_state_type[] = {
  { "error", SSH_PUBLICKEY_STATE_ERROR },
  { "none",  SSH_PUBLICKEY_STATE_NONE  },
  { "valid", SSH_PUBLICKEY_STATE_VALID },
  { "wrong", SSH_PUBLICKEY_STATE_WRONG },
  { NULL,    -1                        }
};

/* Get a type of the message MSG as a list.  car of the list is type
   of the message, cdr is a subtype.

   Return #f on error. */
static SCM
_ssh_message_type_to_scm (ssh_message msg)
{
  int type     = ssh_message_type (msg);
  int subtype  = ssh_message_subtype (msg);
  SCM scm_type = gssh_symbol_to_scm (req_types, type);
  SCM scm_subtype;

  switch (type)
    {
    case SSH_REQUEST_AUTH:
      scm_subtype = gssh_symbol_to_scm (req_auth_subtypes, subtype);
      return scm_list_2 (scm_type, scm_subtype);

    case SSH_REQUEST_CHANNEL_OPEN:
      scm_subtype = gssh_symbol_to_scm (req_channel_open_subtypes, subtype);
      return scm_list_2 (scm_type, scm_subtype);

    case SSH_REQUEST_CHANNEL:
      scm_subtype = gssh_symbol_to_scm (req_channel_subtypes, subtype);
      return scm_list_2 (scm_type, scm_subtype);

    case SSH_REQUEST_GLOBAL:
      scm_subtype = gssh_symbol_to_scm (req_global_subtypes, subtype);
      return scm_list_2 (scm_type, scm_subtype);

    case SSH_REQUEST_SERVICE:
      return scm_list_1 (scm_type);

    default:
      return SCM_BOOL_F;
    }
}


SCM_DEFINE (guile_ssh_message_get_type,
            "message-get-type", 1, 0, 0,
            (SCM msg),
            "\
Get type of the message MSG.\
")
{
  gssh_message_t* message_data = gssh_message_from_scm (msg);
  return _ssh_message_type_to_scm (message_data->message);
}


/* These procedures return a Scheme vector that represents a SSH
   request.  The goal is to unify way of working with requests. */

/* <result> = "#(" <user> <WSP> <password> <WSP> <key> ")" */
static SCM
get_auth_req (ssh_message msg, SCM scm_msg) /* FIXME: accept only SCM */
{
  SCM result = scm_c_make_vector (4, SCM_UNDEFINED);
  const char *user     = ssh_message_auth_user (msg);
  const char *password = ssh_message_auth_password (msg);
  ssh_key public_key   = ssh_message_auth_pubkey (msg);
  SCM pkey_state;

  if (user)
    SCM_SIMPLE_VECTOR_SET (result, 0, scm_from_locale_string (user));
  else
    SCM_SIMPLE_VECTOR_SET (result, 0, SCM_BOOL_F);

  if (password)
    SCM_SIMPLE_VECTOR_SET (result, 1, scm_from_locale_string (password));
  else
    SCM_SIMPLE_VECTOR_SET (result, 1, SCM_BOOL_F);

  SCM_SIMPLE_VECTOR_SET (result, 2, gssh_key_to_scm(public_key, scm_msg));

  pkey_state = gssh_symbol_to_scm (pubkey_state_type,
                                  (int) ssh_message_auth_publickey_state (msg));
  SCM_SIMPLE_VECTOR_SET (result, 3, pkey_state);

  return result;
}

/* <result> = "#(" <term> <WSP> <width> <WSP> <height> <WSP>
              <pxwidth> <WSP> <pxheight> ")" */
static SCM
get_pty_req (ssh_message msg)
{
  SCM result = scm_c_make_vector (5, SCM_UNDEFINED);
  const char *term = ssh_message_channel_request_pty_term (msg);
  int w   = ssh_message_channel_request_pty_width (msg);
  int h   = ssh_message_channel_request_pty_height (msg);
  int pxw = ssh_message_channel_request_pty_pxwidth (msg);
  int pxh = ssh_message_channel_request_pty_pxheight (msg);

  SCM_SIMPLE_VECTOR_SET(result, 0, scm_from_locale_string (term));
  SCM_SIMPLE_VECTOR_SET(result, 1, scm_from_int (w));
  SCM_SIMPLE_VECTOR_SET(result, 2, scm_from_int (h));
  SCM_SIMPLE_VECTOR_SET(result, 3, scm_from_int (pxw));
  SCM_SIMPLE_VECTOR_SET(result, 4, scm_from_int (pxh));

  return result;
}

/* <result> = "#(" <name> <WSP> <value> ")" */
static SCM
get_env_req (ssh_message msg)
{
  SCM result  = scm_c_make_vector (3, SCM_UNDEFINED);
  const char *name  = ssh_message_channel_request_env_name (msg);
  const char *value = ssh_message_channel_request_env_value (msg);

  SCM_SIMPLE_VECTOR_SET(result, 0, scm_from_locale_string (name));
  SCM_SIMPLE_VECTOR_SET(result, 1, scm_from_locale_string (value));

  return result;
}

/* <result> = "#(" <cmd> ")" */
static SCM
get_exec_req (ssh_message msg)
{
  SCM result = scm_c_make_vector (1, SCM_UNDEFINED);
  const char *cmd = ssh_message_channel_request_command (msg);
  SCM_SIMPLE_VECTOR_SET(result, 0, scm_from_locale_string (cmd));
  return result;
}

/* <result> = "#(" <addr> <WSP> <port> ")" */
static SCM
get_global_req (ssh_message msg)
{
  SCM result = scm_c_make_vector (2, SCM_UNDEFINED);
  const char *addr = ssh_message_global_request_address (msg);
  int port = ssh_message_global_request_port (msg);

  SCM_SIMPLE_VECTOR_SET(result, 0, scm_from_locale_string (addr));
  SCM_SIMPLE_VECTOR_SET(result, 1, scm_from_int (port));

  return result;
}

/* <result> = "#(" <service-request> ")" */
static SCM
get_service_req (ssh_message msg)
{
  SCM result = scm_c_make_vector (1, SCM_UNDEFINED);
  const char *req = ssh_message_service_service (msg);

  SCM_SIMPLE_VECTOR_SET(result, 0, scm_from_locale_string (req));

  return result;
}

/* <result> = "#(" <orig> <WSP> <orig-port> <WSP>
              <dest> <WSP> <dest-port> ")" */
static SCM
get_channel_open_req (ssh_message msg)
{
  const char *orig = ssh_message_channel_request_open_originator (msg);
  int orig_port    = ssh_message_channel_request_open_originator_port (msg);
  const char *dest = ssh_message_channel_request_open_destination (msg);
  int dest_port    = ssh_message_channel_request_open_destination_port (msg);
  SCM result;

  if ((! orig) || (! dest))
    return SCM_BOOL_F;

  result = scm_c_make_vector (4, SCM_UNDEFINED);

  SCM_SIMPLE_VECTOR_SET (result, 0, scm_from_locale_string (orig));
  SCM_SIMPLE_VECTOR_SET (result, 1, scm_from_int (orig_port));
  SCM_SIMPLE_VECTOR_SET (result, 2, scm_from_locale_string (dest));
  SCM_SIMPLE_VECTOR_SET (result, 3, scm_from_int (dest_port));

  return result;
}

static SCM
get_subsystem_req (ssh_message msg)
{
  const char* subsystem = ssh_message_channel_request_subsystem (msg);
  SCM result = SCM_BOOL_F;

  if (subsystem)
    {
      result = scm_c_make_vector (1, SCM_UNDEFINED);
      SCM_SIMPLE_VECTOR_SET (result, 0, scm_from_locale_string (subsystem));
    }

  return result;
}

SCM_DEFINE (guile_ssh_message_get_req,
            "message-get-req", 1, 0, 0,
            (SCM msg),
            "\
Get a request object from the message MSG\
")
#define FUNC_NAME s_guile_ssh_message_get_req
{
  gssh_message_t* message_data = gssh_message_from_scm (msg);
  ssh_message ssh_msg = message_data->message;
  int type = ssh_message_type (ssh_msg);

  switch (type)
    {
    case SSH_REQUEST_SERVICE:
      return get_service_req (ssh_msg);

    case SSH_REQUEST_AUTH:
      return get_auth_req (ssh_msg, msg);

    case SSH_REQUEST_CHANNEL_OPEN:
      {
        SCM res = get_channel_open_req (ssh_msg);
        if (scm_is_true (res))
          return res;
        else
          guile_ssh_error1 (FUNC_NAME, "Wrong channel-open request", msg);
      }

    case SSH_REQUEST_CHANNEL:
      {
        int subtype = ssh_message_subtype (ssh_msg);
        switch (subtype)
          {
          case SSH_CHANNEL_REQUEST_PTY:
            return get_pty_req (ssh_msg);

          case SSH_CHANNEL_REQUEST_EXEC:
            return get_exec_req (ssh_msg);

          case SSH_CHANNEL_REQUEST_ENV:
            return get_env_req (ssh_msg);

          case SSH_CHANNEL_REQUEST_SUBSYSTEM:
            return get_subsystem_req (ssh_msg);

          default:
            guile_ssh_error1 (FUNC_NAME, "Wrong message subtype",
                              scm_from_int (subtype));
          }
      }

    case SSH_REQUEST_GLOBAL:
      return get_global_req (ssh_msg);

    default:
      guile_ssh_error1 (FUNC_NAME, "Wrong message type",
                        gssh_symbol_to_scm (req_types, type));

    }

  return SCM_BOOL_F;            /* Never reached. */
}
#undef FUNC_NAME


/* A convenient wrapper for `scm_member' that returns its result as
   int. */
static inline int
_scm_member_p (SCM elem, SCM lst)
{
  return scm_is_true (scm_member (elem, lst));
}

SCM_DEFINE (guile_ssh_message_auth_set_methods_x,
            "message-auth-set-methods!", 2, 0, 0,
            (SCM msg, SCM methods_list),
            "\
Set authentication methods.\n\
Return value is undefined.\
")
#define FUNC_NAME s_guile_ssh_message_auth_set_methods_x
{
  gssh_message_t* message_data = gssh_message_from_scm (msg);
  int methods = 0;
  int res;

  SCM_ASSERT (scm_list_p (methods_list), methods_list, SCM_ARG2, FUNC_NAME);

  if (_scm_member_p (scm_from_locale_symbol ("password"), methods_list))
    methods |= SSH_AUTH_METHOD_PASSWORD;

  if (_scm_member_p (scm_from_locale_symbol ("public-key"), methods_list))
    methods |= SSH_AUTH_METHOD_PUBLICKEY;

  if (_scm_member_p (scm_from_locale_symbol ("interactive"), methods_list))
    methods |= SSH_AUTH_METHOD_INTERACTIVE;

  if (_scm_member_p (scm_from_locale_symbol ("host-based"), methods_list))
    methods |= SSH_AUTH_METHOD_HOSTBASED;

  res = ssh_message_auth_set_methods (message_data->message, methods);
  _gssh_log_debug_format(FUNC_NAME, scm_list_2 (msg, methods_list),
                         "result: %d", res);
  if (res != SSH_OK)
    {
      guile_ssh_error1 (FUNC_NAME, "Unable to set auth methods",
                        scm_list_2 (msg, methods_list));
    }

  return SCM_UNDEFINED;
}
#undef FUNC_NAME


SCM_DEFINE (guile_ssh_message_get_session,
            "message-get-session", 1, 0, 0,
            (SCM message),
            "\
Get the session from which the MESSAGE was received.  Return the session.\
")
{
  gssh_message_t* md = gssh_message_from_scm (message);
  return md->session;
}


void
init_message_func (void)
{
#include "message-func.x"
}

/* message-func.c ends here */