Add simplistic telnet control interface

This might turn into a complete wire protocol with special
client software. For now it will be a simple client interface
that you can use with telnet to do certain things.

This is using flex to implement the parsing. Implementation
and more commands will follow.

4 files changed, 377 insertions, 1 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 62afff2e4..b0e29ee21 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -5,5 +5,5 @@ sbin_PROGRAMS = bsc_hack
 
 bsc_hack_SOURCES = bsc_hack.c misdn.c abis_rsl.c abis_nm.c gsm_04_08.c gsm_data.c \
 		gsm_subscriber.c msgb.c select.c chan_alloc.c timer.c debug.c db.c \
-		gsm_04_11.c
+		gsm_04_11.c telnet_interface.c telnet_parser.l
 bsc_hack_LDADD = -ldl -ldbi
diff --git a/src/bsc_hack.c b/src/bsc_hack.c
index c59024a90..a3aefc664 100644
--- a/src/bsc_hack.c
+++ b/src/bsc_hack.c
@@ -1,6 +1,7 @@
 /* A hackish minimal BSC (+MSC +HLR) implementation */
 
 /* (C) 2008 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
  * All Rights Reserved
  *
  * This program is free software; you can redistribute it and/or modify
@@ -42,6 +43,7 @@
 #include <openbsc/abis_nm.h>
 #include <openbsc/debug.h>
 #include <openbsc/misdn.h>
+#include <openbsc/telnet_interface.h>
 
 /* global pointer to the gsm network data structure */
 static struct gsm_network *gsmnet;
@@ -685,6 +687,7 @@ static int bootstrap_network(void)
 	gsmnet->call_state_changed = bsc_hack_call_state_changed;
 #endif
 
+	telnet_init(gsmnet, 4242);
 	if (mi_setup(bts, 0, mi_cb) < 0)
 		return -EIO;
 
diff --git a/src/telnet_interface.c b/src/telnet_interface.c
new file mode 100644
index 000000000..b0a8e4334
--- /dev/null
+++ b/src/telnet_interface.c
@@ -0,0 +1,193 @@
+/* minimalistic telnet/network interface it might turn into a wire interface */
+/* (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * All Rights Reserved
+ *
+ * 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 <sys/socket.h>
+#include <netinet/in.h>
+#include <malloc.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <openbsc/telnet_interface.h>
+
+extern void telnet_parse(struct telnet_connection *connection, char *line);
+
+/* per connection data */
+LLIST_HEAD(active_connections);
+
+/* per network data */
+static int telnet_new_connection(struct bsc_fd *fd, unsigned int what);
+static struct bsc_fd server_socket = {
+	.when	    = BSC_FD_READ,
+	.cb	    = telnet_new_connection,
+	.priv_nr    = 0,
+};
+
+void telnet_init(struct gsm_network *network, int port) {
+	struct sockaddr_in sock_addr;
+	int fd;
+
+	fd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
+
+	if (fd < 0) {
+		perror("Telnet interface socket creation failed");
+		return;
+	}
+
+	memset(&sock_addr, 0, sizeof(sock_addr));
+	sock_addr.sin_family = AF_INET;
+	sock_addr.sin_port = htons(port);
+	sock_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+
+	if (bind(fd, (struct sockaddr*)&sock_addr, sizeof(sock_addr)) < 0) {
+		perror("Telnet interface failed to bind");
+		return;
+	}
+
+	if (listen(fd, 0) < 0) {
+		perror("Telnet interface failed to listen");
+		return;
+	}
+
+	server_socket.data = network;
+	server_socket.fd = fd;
+	bsc_register_fd(&server_socket);
+}
+
+void telnet_write_help(int fd) {
+	int ret;
+	static char *msg =
+		"Help for the ad-hoc telnet command line interface\n"
+		"The generic pattern is CMD LEN DATA\\n or just CMD\n"
+		"where CMD is one of the following:\n"
+		"help\n"
+		"page IMSI (type)\n"
+		"call IMSI (number)\n"
+		"get_channel IMSI Add use count on an active channel\n"
+		"put_channel IMSI Remove use count on an active channel\n"
+		"48 IMSI 0xAB 0xEF...Send GSM 04.08\n"
+		"11 IMSI 0xAB 0xEF...Send GSM 04.11\n";
+
+	ret = write(fd, msg, strlen(msg));
+}
+
+static void print_welcome(int fd) {
+	int ret;
+	static char *msg =
+		"Welcome to the OpenBSC Control interface\n"
+		"Copyright (C) 2008, 2009 Harald Welte\n"
+		"Contributions by Daniel Willmann, Jan Lübbe, "
+		"Stefan Schmidt, Holger Freyther\n\n"
+		"License GPLv2+: GNU GPL version 2 or later "
+		"<http://gnu.org/licenses/gpl.html>\n"
+		"This is free software: you are free to change "
+		"and redistribute it.\n"
+		"There is NO WARRANTY, to the extent permitted "
+		"by law.\nType \"help\" to get a short introduction.\n";
+
+	ret = write(fd, msg, strlen(msg));
+}
+
+int telnet_close_client(struct bsc_fd *fd) {
+	struct telnet_connection *conn = (struct telnet_connection*)fd->data;
+
+	close(fd->fd);
+	bsc_unregister_fd(fd);
+	llist_del(&conn->entry);
+	free(conn);
+	return 0;
+}
+
+void telnet_error_client(int fd) {
+	int ret;
+	static char *msg = "Something went wrong. Please try again.\n";
+
+	printf("Error\n");
+	ret = write(fd, msg, strlen(msg));
+}
+
+void telnet_page(struct telnet_connection *connection, const char *imsi, int page) {
+	printf("going to page: '%s' %d\n", imsi, page);
+}
+
+void telnet_put_channel(struct telnet_connection *connection, const char *imsi) {
+	printf("put_channel: '%s'\n", imsi);
+}
+
+void telnet_get_channel(struct telnet_connection *connection, const char *imsi) {
+	printf("get_channel: '%s'\n", imsi);
+}
+
+void telnet_call(struct telnet_connection *connection, const char* imsi,
+		const char *origin) {
+	printf("calling: '%s' from: '%s'\n", imsi, origin);
+}
+
+void telnet_send_gsm_48(struct telnet_connection *connection) {
+	printf("sending gsm04.08 message\n");
+}
+
+void telnet_send_gsm_11(struct telnet_connection *connection) {
+	printf("sending gsm04.11 message\n");
+}
+
+static int client_data(struct bsc_fd *fd, unsigned int what) {
+	char buf[4096];
+	int ret;
+
+	ret = read(fd->fd, buf, sizeof(buf)-1);
+	buf[ret] = '\0';
+
+	/* connection is gone */
+	if (ret <= 0)
+		return telnet_close_client(fd);
+
+	/* time to parse. This code assumes that the input is line based */
+	telnet_parse((struct telnet_connection*)fd->data, buf);
+
+	return 0;
+}
+
+static int telnet_new_connection(struct bsc_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);
+
+	if (new_connection < 0) {
+		perror("telnet accept failed");
+		return -1;
+	}
+
+
+	connection = (struct telnet_connection*)malloc(sizeof(*connection));
+	memset(connection, 0, sizeof(*connection));
+	connection->network = (struct gsm_network*)fd->data;
+	connection->fd.data = connection;
+	connection->fd.fd = new_connection;
+	connection->fd.when = BSC_FD_READ;
+	connection->fd.cb = client_data;
+	bsc_register_fd(&connection->fd);
+	llist_add_tail(&connection->entry, &active_connections);
+
+	print_welcome(new_connection);
+
+	return 0;
+}
diff --git a/src/telnet_parser.l b/src/telnet_parser.l
new file mode 100644
index 000000000..3af0d5818
--- /dev/null
+++ b/src/telnet_parser.l
@@ -0,0 +1,180 @@
+/* (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * All Rights Reserved
+ *
+ * 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.
+ *
+ */
+/*
+ * I'm lazy and will not introduce lemon to this game. Our telnet
+ * interface is matching line based so we can have a pattern that
+ * is matching a line and everyone will be happy.
+ */
+
+%option never-interactive
+%option noyywrap
+%option	reentrant
+
+%{
+#include <string.h>
+#include <openbsc/telnet_interface.h>
+
+extern char *strndup(const char *s, size_t n);
+extern void telnet_write_help(int);
+extern void telnet_close_client(struct bsc_fd*);
+extern void telnet_error_client(int fd);
+extern void telnet_page(struct telnet_connection *con, const char *imsi, int page);
+extern void telnet_call(struct telnet_connection *con, const char *imsi,
+			const char* origin);
+extern void telnet_put_channel(struct telnet_connection*, const char *imsi);
+extern void telnet_get_channel(struct telnet_connection*, const char *imsi);
+extern void telnet_send_gsm_48(struct telnet_connection*);
+extern void telnet_send_gsm_11(struct telnet_connection*);
+
+static const int PAGE_LEN = 5; /* "page " */
+static const int CALL_LEN = 5; /* "call " */
+static const int PUT_LEN = 12; /* "put_channel " */
+static const int GET_LEN = 12; /* "get_channel " */
+static const int NET_LEN = 3;  /* "48 " "11 " */
+
+#define YY_EXTRA_TYPE struct telnet_connection*
+
+/* the string is null terminated */
+static int parse_hex(char *hex)
+{
+	int byte;
+	sscanf(hex, "%x", &byte);
+	return byte;
+}
+
+#define PREPARE_STRING(len) \
+		yytext[yyleng-1] = '\0'; \
+                char *str = yytext + len; \
+		char *pag = strstr(str, "\r"); \
+		if (pag) pag[0] = '\0'; \
+		pag = strstr(str, "\n"); \
+		if (pag) pag[0] = '\0';
+
+%}
+
+CMD_HELP	"help"
+CMD_EXIT	"exit"
+CMD_CLOSE	"close"
+CMD_PAGE	"page"
+CMD_GET_CHANNEL	"get_channel"
+CMD_PUT_CHANNEL "put_channel"
+CMD_CALL	"call"
+CMD_48		"48"
+CMD_11		"11"
+
+LINE_END	\n|\r\n
+HEX		[0][x][0-9a-zA-Z][0-9a-zA-Z]
+
+%s  READ_HEX_BYTES
+
+%%
+{CMD_HELP}{LINE_END}		{telnet_write_help(yyextra->fd.fd); yyterminate();}
+{CMD_EXIT}{LINE_END}		{telnet_close_client(&yyextra->fd); yyterminate();}
+{CMD_CLOSE}{LINE_END}		{telnet_close_client(&yyextra->fd); yyterminate();}
+{CMD_PAGE}[ ][0-9]+{LINE_END} {
+				    PREPARE_STRING(PAGE_LEN)
+                                    telnet_page(yyextra, str, 0);
+				    yyterminate();
+				}
+{CMD_PAGE}[ ][0-9]+[ ][0-2]{LINE_END} {
+				    PREPARE_STRING(PAGE_LEN)
+				    char *sp = strstr(str, " ");
+				    sp[0] = '\0';
+                                    telnet_page(yyextra, str, atoi(sp+1));
+				    yyterminate();
+				}
+{CMD_PUT_CHANNEL}[ ][0-9]+{LINE_END} {
+				    PREPARE_STRING(PUT_LEN)
+                                    telnet_put_channel(yyextra, str);
+				    yyterminate();
+				}
+{CMD_GET_CHANNEL}[ ][0-9]+{LINE_END} {
+				    PREPARE_STRING(GET_LEN)
+                                    telnet_get_channel(yyextra, str);
+				    yyterminate();
+				}
+{CMD_CALL}[ ][0-9]+[ ][0-9]+{LINE_END} {
+				    PREPARE_STRING(CALL_LEN)
+				    char *sp = strstr(str, " ");
+				    sp[0] = '\0';
+                                    telnet_call(yyextra, str, sp+1);
+				    yyterminate();
+				}
+{CMD_CALL}[ ][0-9]+{LINE_END} {
+				    PREPARE_STRING(CALL_LEN)
+                                    telnet_call(yyextra, str, NULL);
+				    yyterminate();
+				}
+<READ_HEX_BYTES>{HEX}		{
+				    if (yyextra->read >= sizeof(yyextra->commands)) {
+					yyterminate();
+				    }
+				    yytext[yyleng] = '\0';
+				    yyextra->commands[yyextra->read++] = parse_hex(yytext+2);
+				}
+<READ_HEX_BYTES>{LINE_END}	{
+				    if (yyextra->command == TELNET_COMMAND_11) {
+					telnet_send_gsm_11(yyextra);
+				    } else if (yyextra->command == TELNET_COMMAND_48) {
+					telnet_send_gsm_48(yyextra);
+				    }
+
+				    if (yyextra->imsi) {
+					free(yyextra->imsi);
+					yyextra->imsi = NULL;
+				    }
+				    yyterminate();
+				}
+<INITIAL>{CMD_48}[ ][0-9]+	{
+				    BEGIN READ_HEX_BYTES;
+				    yyextra->read = 0;
+				    yyextra->command = TELNET_COMMAND_48;
+				    yytext[yyleng-1] = '\0';
+				    yyextra->imsi = strdup(yytext);
+				}
+
+<INITIAL>{CMD_11}[ ][0-9]+	{
+				    BEGIN READ_HEX_BYTES;
+				    yyextra->read = 0;
+				    yyextra->command = TELNET_COMMAND_11;
+				    yytext[yyleng-1] = '\0';
+				    yyextra->imsi = strdup(yytext);
+				}
+
+
+
+[ \t\r\n]			/* Ommit */
+.				{ telnet_error_client(yyextra->fd.fd); yyterminate(); }
+
+%%
+
+void telnet_parse(struct telnet_connection *conn, char *buf)
+{
+	yyscan_t scanner;
+	yylex_init(&scanner);
+	yyset_extra(conn, scanner);
+	yy_scan_string(buf, scanner);
+	yylex(scanner);
+	yylex_destroy(scanner);
+
+	if (conn->imsi) {
+		free(conn->imsi);
+		conn->imsi = NULL;
+	}
+}