[PATCH 1/3] vty: add bind command for telnet vty line

[Neels Hofmeyr]

Add VTY command
    line vty
     bind A.B.C.D

The command merely stores the configured IP-address, which can then be used by
the calling main program to set the telnet port of the VTY line. (Commits in
openbsc and osmo-iuh will follow up on this.)

Add function vty_get_bind_addr() to publish the address in the vty.h API.

Add static vty_bind_addr to store.

For allocation/freeing reasons, a NULL address defaults to 127.0.0.1.

BTW, I decided against allowing keywords 'any' and 'localhost' in place of an
actual IP address to make sure a written config is always identical to the
parsed config.
---
 include/osmocom/vty/vty.h |  3 +++
 src/vty/vty.c             | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/include/osmocom/vty/vty.h b/include/osmocom/vty/vty.h
index 3684397..43cb0cf 100644
--- a/include/osmocom/vty/vty.h
+++ b/include/osmocom/vty/vty.h
@@ -186,6 +186,9 @@ void *vty_current_index(struct vty *);
 int vty_current_node(struct vty *vty);
 int vty_go_parent(struct vty *vty);
 
+/* Return IP address passed to the 'line vty'/'bind' command, or "127.0.0.1" */
+const char *vty_get_bind_addr(void);
+
 extern void *tall_vty_ctx;
 
 extern struct cmd_element cfg_description_cmd;
diff --git a/src/vty/vty.c b/src/vty/vty.c
index 5bcbe4a..7e27d7e 100644
--- a/src/vty/vty.c
+++ b/src/vty/vty.c
@@ -75,6 +75,10 @@ vector Vvty_serv_thread;
 
 char *vty_cwd = NULL;
 
+/* IP address passed to the 'line vty'/'bind' command */
+static const char *vty_bind_addr = NULL;
+#define VTY_BIND_ADDR_DEFAULT "127.0.0.1"
+
 /* Configure lock. */
 static int vty_config;
 
@@ -1585,6 +1589,29 @@ DEFUN(no_vty_login,
 	return CMD_SUCCESS;
 }
 
+/* vty bind */
+DEFUN(vty_bind, vty_bind_cmd, "bind A.B.C.D",
+      "Accept VTY telnet connections on local interface\n"
+      "Local interface IP address (default: " VTY_BIND_ADDR_DEFAULT ")\n")
+{
+	/* Avoid (small) mem leak: initially, vty_bind_addr is NULL. Whenever
+	 * this gets called, it is set to a strdup. So whenever it is non-NULL,
+	 * free it first. See also vty_get_bind_addr() for the NULL default. */
+	if (vty_bind_addr) {
+		talloc_free((void*)vty_bind_addr);
+		vty_bind_addr = NULL;
+	}
+	vty_bind_addr = talloc_strdup(tall_vty_ctx, argv[0]);
+	return CMD_SUCCESS;
+}
+
+const char *vty_get_bind_addr(void)
+{
+	if (!vty_bind_addr)
+		return VTY_BIND_ADDR_DEFAULT;
+	return vty_bind_addr;
+}
+
 DEFUN(service_advanced_vty,
       service_advanced_vty_cmd,
       "service advanced-vty",
@@ -1654,6 +1681,10 @@ static int vty_config_write(struct vty *vty)
 	if (!password_check)
 		vty_out(vty, " no login%s", VTY_NEWLINE);
 
+	/* bind */
+	if (vty_bind_addr)
+		vty_out(vty, " bind %s%s", vty_bind_addr, VTY_NEWLINE);
+
 	vty_out(vty, "!%s", VTY_NEWLINE);
 
 	return CMD_SUCCESS;
@@ -1757,6 +1788,7 @@ void vty_init(struct vty_app_info *app_info)
 	vty_install_default(VTY_NODE);
 	install_element(VTY_NODE, &vty_login_cmd);
 	install_element(VTY_NODE, &no_vty_login_cmd);
+	install_element(VTY_NODE, &vty_bind_cmd);
 }
 
 /*! \brief Read the configuration file using the VTY code
-- 
2.1.4