/* (C) 2009-2010 by Holger Hans Peter Freyther * (C) 2010 by Sylvain Munaut * All Rights Reserved * * SPDX-License-Identifier: GPL-2.0+ * * 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 2 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, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /*! \file telnet_interface.c * Telnet interface towards Osmocom VTY * * This module contains the code implementing a telnet server for VTY * access. This telnet server gets linked into each libosmovty-using * process in order to enable interactive command-line introspection, * interaction and configuration. * * You typically call \ref telnet_init or \ref telnet_init_dynif once * from your application code to enable this. */ /* per connection data */ LLIST_HEAD(active_connections); static void *tall_telnet_ctx; /* per network data */ static int telnet_new_connection(struct osmo_fd *fd, unsigned int what); static struct osmo_fd server_socket = { .when = BSC_FD_READ, .cb = telnet_new_connection, .priv_nr = 0, }; /*! Initialize telnet based VTY interface listening to 127.0.0.1 * \param[in] tall_ctx \ref talloc context * \param[in] priv private data to be passed to callback * \param[in] port UDP port number */ int telnet_init(void *tall_ctx, void *priv, int port) { return telnet_init_dynif(tall_ctx, priv, "127.0.0.1", port); } /*! Initialize telnet based VTY interface * \param[in] tall_ctx \ref talloc context * \param[in] priv private data to be passed to callback * \param[in] ip IP to listen to ('::1' for localhost, '::0' for all, ...) * \param[in] port UDP port number */ int telnet_init_dynif(void *tall_ctx, void *priv, const char *ip, int port) { int rc; tall_telnet_ctx = talloc_named_const(tall_ctx, 1, "telnet_connection"); rc = osmo_sock_init_ofd( &server_socket, AF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, ip, port, OSMO_SOCK_F_BIND ); server_socket.data = priv; if (rc < 0) { LOGP(DLGLOBAL, LOGL_ERROR, "Cannot bind telnet at %s %d\n", ip, port); return -1; } LOGP(DLGLOBAL, LOGL_NOTICE, "Available via telnet %s %d\n", ip, port); return 0; } extern struct host host; /*! close a telnet connection */ int telnet_close_client(struct osmo_fd *fd) { struct telnet_connection *conn = (struct telnet_connection*)fd->data; close(fd->fd); osmo_fd_unregister(fd); if (conn->dbg) { log_del_target(conn->dbg); talloc_free(conn->dbg); } llist_del(&conn->entry); talloc_free(conn); return 0; } static int client_data(struct osmo_fd *fd, unsigned int what) { struct telnet_connection *conn = fd->data; int rc = 0; if (what & BSC_FD_READ) { conn->fd.when &= ~BSC_FD_READ; rc = vty_read(conn->vty); } /* vty might have been closed from vithin vty_read() */ if (rc == -EBADF) return rc; if (what & BSC_FD_WRITE) { rc = buffer_flush_all(conn->vty->obuf, fd->fd); if (rc == BUFFER_EMPTY) conn->fd.when &= ~BSC_FD_WRITE; } return rc; } static int telnet_new_connection(struct osmo_fd *fd, unsigned int what) { struct telnet_connection *connection; struct sockaddr_in sockaddr; socklen_t len = sizeof(sockaddr); int new_connection = accept(fd->fd, (struct sockaddr*)&sockaddr, &len); int rc; if (new_connection < 0) { LOGP(0, LOGL_ERROR, "telnet accept failed\n"); return new_connection; } connection = talloc_zero(tall_telnet_ctx, struct telnet_connection); connection->priv = fd->data; connection->fd.data = connection; connection->fd.fd = new_connection; connection->fd.when = BSC_FD_READ; connection->fd.cb = client_data; rc = osmo_fd_register(&connection->fd); if (rc < 0) { talloc_free(connection); return rc; } llist_add_tail(&connection->entry, &active_connections); connection->vty = vty_create(new_connection, connection); if (!connection->vty) { LOGP(0, LOGL_ERROR, "couldn't create VTY\n"); /* vty_create() is already closing the fd if it returns NULL */ talloc_free(connection); return -1; } return 0; } /*! callback from core VTY code about VTY related events */ void vty_event(enum event event, int sock, struct vty *vty) { struct vty_signal_data sig_data = { 0, }; struct telnet_connection *connection = vty->priv; struct osmo_fd *bfd; if (vty->type != VTY_TERM) return; sig_data.event = event; sig_data.sock = sock; sig_data.vty = vty; osmo_signal_dispatch(SS_L_VTY, S_VTY_EVENT, &sig_data); if (!connection) return; bfd = &connection->fd; switch (event) { case VTY_READ: bfd->when |= BSC_FD_READ; break; case VTY_WRITE: bfd->when |= BSC_FD_WRITE; break; case VTY_CLOSED: /* vty layer is about to free() vty */ telnet_close_client(bfd); break; default: break; } } /*! Close all telnet connections and release the telnet socket */ void telnet_exit(void) { struct telnet_connection *tc, *tc2; llist_for_each_entry_safe(tc, tc2, &active_connections, entry) telnet_close_client(&tc->fd); osmo_fd_unregister(&server_socket); close(server_socket.fd); talloc_free(tall_telnet_ctx); }