diff mbox

[RFC] wpa-supplicant: add capability to run action script directly

Message ID 54772018.2090201@barfooze.de
State Rejected
Headers show

Commit Message

John Spencer Nov. 27, 2014, 12:59 p.m. UTC 
Instead of having to run wpa_cli as a service to be able to execute an 
action script on CONNECT/DISCONNECT events (for the purpose of being
able to get a DHCP address or assign one manually), it is much simpler
and less resource-consuming to just run the action script directly from
wpa_supplicant, which runs anyway.
The dbus functionality is no option either as it requires running a 
daemon permanently as well (plus dbus may not even be installed, as is 
the case on sabotage linux).

The action script pathname is specified via a action_script variable in 
the global section of wpa_supplicant.conf

example action script:
.#!/bin/sh
itf="$1"
state="$2"
case "$state" in
CONNECTED) dhclient "$itf" ;;
DISCONNECTED) ifconfig "$itf" down ;;
esac

Please note that the code to pass the SSID of the connected wifi as a 
third parameter doesn't seem to work atm (only passes an empty string).

Comments

Jouni Malinen Nov. 27, 2014, 2:04 p.m. UTC | #1 
On Thu, Nov 27, 2014 at 01:59:04PM +0100, John Spencer wrote:
> Instead of having to run wpa_cli as a service to be able to execute
> an action script on CONNECT/DISCONNECT events (for the purpose of
> being
> able to get a DHCP address or assign one manually), it is much simpler
> and less resource-consuming to just run the action script directly from
> wpa_supplicant, which runs anyway.

This is against the policy of avoiding any external programs from being
started by wpa_supplicant (or hostapd for that matter). That control
interface-based design was used exactly to be able to avoid this type of
changes.

In addition to that specific policy, blocking wpa_supplicant here:

> +		} else {
> +			int loc;
> +			waitpid(child, &loc, 0);
> +		}

would be undesirable. There are number of operations (e.g., replying to
4-way handshake immediately after association or replying to some action
frames after completion of 4-way handshake) that should not be delayed.
diff mbox

Patch

diff -ru wpa_supplicant-2.3.org/wpa_supplicant/config.c wpa_supplicant-2.3/wpa_supplicant/config.c
--- wpa_supplicant-2.3.org/wpa_supplicant/config.c	2014-11-26 12:20:05.504066398 +0100
+++ wpa_supplicant-2.3/wpa_supplicant/config.c	2014-11-26 12:33:53.742067707 +0100
@@ -3806,6 +3806,7 @@ 
 #define IPV4(f) #f, wpa_global_config_parse_ipv4, OFFSET(f), NULL, NULL
 
 static const struct global_parse_data global_fields[] = {
+	{ STR(action_script), 0 },
 #ifdef CONFIG_CTRL_IFACE
 	{ STR(ctrl_interface), 0 },
 	{ FUNC_NO_VAR(no_ctrl_interface), 0 },
Only in wpa_supplicant-2.3/wpa_supplicant: config.d
diff -ru wpa_supplicant-2.3.org/wpa_supplicant/config.h wpa_supplicant-2.3/wpa_supplicant/config.h
--- wpa_supplicant-2.3.org/wpa_supplicant/config.h	2014-11-26 12:20:05.497066398 +0100
+++ wpa_supplicant-2.3/wpa_supplicant/config.h	2014-11-26 12:53:18.220069549 +0100
@@ -329,6 +329,10 @@ 
  * for each.
  */
 struct wpa_config {
+	/* action_script: a script that is executed on connect and disconnect
+	 * events. gets interface name, state, and bssid as command line args */
+	char * action_script;
+
 	/**
 	 * ssid - Head of the global network list
 	 *
Binary files wpa_supplicant-2.3.org/wpa_supplicant/config.o and wpa_supplicant-2.3/wpa_supplicant/config.o differ
diff -ru wpa_supplicant-2.3.org/wpa_supplicant/notify.c wpa_supplicant-2.3/wpa_supplicant/notify.c
--- wpa_supplicant-2.3.org/wpa_supplicant/notify.c	2014-11-26 12:20:05.500066398 +0100
+++ wpa_supplicant-2.3/wpa_supplicant/notify.c	2014-11-26 12:54:49.356069693 +0100
@@ -67,6 +67,27 @@ 
 	wpas_dbus_unregister_interface(wpa_s);
 }
 
+#include <sys/wait.h>
+static void connect_notify(struct wpa_supplicant *wpa_s, int disconnected) {
+	if(disconnected) wpas_p2p_notif_disconnected(wpa_s);
+	else wpas_p2p_notif_connected(wpa_s);
+	if (wpa_s->conf->action_script) {
+		pid_t child;
+		if(!(child = fork())) {
+			execve(wpa_s->conf->action_script, (char* const[]) {
+				wpa_s->conf->action_script,
+				wpa_s->ifname,
+				disconnected ? "DISCONNECTED" : "CONNECTED",
+				wpa_s->current_ssid && wpa_s->current_ssid->ssid ?
+					wpa_ssid_txt(wpa_s->current_ssid->ssid, wpa_s->current_ssid->ssid_len)
+					: "",
+				0}, (char* const[]) {0});
+		} else {
+			int loc;
+			waitpid(child, &loc, 0);
+		}
+	}
+}
 
 void wpas_notify_state_changed(struct wpa_supplicant *wpa_s,
 			       enum wpa_states new_state,
@@ -80,9 +101,9 @@ 
 	wpas_dbus_signal_prop_changed(wpa_s, WPAS_DBUS_PROP_STATE);
 
 	if (new_state == WPA_COMPLETED)
-		wpas_p2p_notif_connected(wpa_s);
+		connect_notify(wpa_s, 0);
 	else if (old_state >= WPA_ASSOCIATED && new_state < WPA_ASSOCIATED)
-		wpas_p2p_notif_disconnected(wpa_s);
+		connect_notify(wpa_s, 1);
 
 	sme_state_changed(wpa_s);