From 4322d8323cc41f1175ab5724b64b803a8997c495 Mon Sep 17 00:00:00 2001
From: Jan-Philipp Litza <janphilipp@litza.de>
Date: Sun, 4 Dec 2016 19:51:41 +0100
Subject: [PATCH] gluon-airtime: Autodetect interfaces

---
 package/gluon-airtime/src/Makefile       |  4 +-
 package/gluon-airtime/src/airtime-test.c | 20 ++++---
 package/gluon-airtime/src/airtime.c      | 22 +-------
 package/gluon-airtime/src/airtime.h      |  7 +--
 package/gluon-airtime/src/ifaces.c       | 66 ++++++++++++++++++++++++
 package/gluon-airtime/src/ifaces.h       |  9 ++++
 package/gluon-airtime/src/respondd.c     | 25 +++++----
 7 files changed, 104 insertions(+), 49 deletions(-)
 create mode 100644 package/gluon-airtime/src/ifaces.c
 create mode 100644 package/gluon-airtime/src/ifaces.h

diff --git a/package/gluon-airtime/src/Makefile b/package/gluon-airtime/src/Makefile
index 025c98db..1a6c0ed0 100644
--- a/package/gluon-airtime/src/Makefile
+++ b/package/gluon-airtime/src/Makefile
@@ -14,10 +14,10 @@ all: respondd.so
 %.c: %.h
 
 # sudo apt install libnl-3-dev
-airtime-test: airtime.c airtime-test.c
+airtime-test: airtime.c ifaces.c airtime-test.c
 	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -fPIC -D_GNU_SOURCE -lnl-tiny -o $@ $^ $(LDLIBS)
 
-respondd.so: airtime.c respondd.c
+respondd.so: airtime.c ifaces.c respondd.c
 	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -shared -fPIC -D_GNU_SOURCE -lnl-tiny -o $@ $^ $(LDLIBS)
 
 clean:
diff --git a/package/gluon-airtime/src/airtime-test.c b/package/gluon-airtime/src/airtime-test.c
index 85773f9e..a82861f1 100644
--- a/package/gluon-airtime/src/airtime-test.c
+++ b/package/gluon-airtime/src/airtime-test.c
@@ -1,19 +1,23 @@
 #include <stdio.h>
+#include <stdlib.h>
 #include "airtime.h"
+#include "ifaces.h"
 
 void print_result(struct airtime_result *);
 
 int main(int argc, char *argv[]) {
-	struct airtime *a;
+	struct airtime_result a;
+	struct iface_list *ifaces;
+	void *freeptr;
 
-	if (argc != 3) {
-		fprintf(stderr,"Usage: %s <wifi1> <wifi2>\n", argv[0]);
-		return 1;
+	ifaces = get_ifaces();
+	while (ifaces != NULL) {
+		get_airtime(&a, ifaces->ifx);
+		print_result(&a);
+		freeptr = ifaces;
+		ifaces = ifaces->next;
+		free(freeptr);
 	}
-
-	a = get_airtime(argv[1], argv[2]);
-	print_result(&a->radio0);
-	print_result(&a->radio1);
 }
 
 void print_result(struct airtime_result *result){
diff --git a/package/gluon-airtime/src/airtime.c b/package/gluon-airtime/src/airtime.c
index 108d6d56..e8c18427 100644
--- a/package/gluon-airtime/src/airtime.c
+++ b/package/gluon-airtime/src/airtime.c
@@ -33,11 +33,6 @@
 
 #include "airtime.h"
 
-static struct airtime cur_airtime = {
-	{ .frequency = 0 },
-	{ .frequency = 0 },
-};
-
 /*
  * Excerpt from nl80211.h:
  * enum nl80211_survey_info - survey information
@@ -103,9 +98,9 @@ abort:
 	return NL_SKIP;
 }
 
-static int get_airtime_for_interface(struct airtime_result *result, const char *interface) {
+int get_airtime(struct airtime_result *result, int ifx) {
 	int error = 0;
-	int ctrl, ifx;
+	int ctrl;
 	struct nl_sock *sk = NULL;
 	struct nl_msg *msg = NULL;
 
@@ -118,12 +113,6 @@ static int get_airtime_for_interface(struct airtime_result *result, const char *
 	CHECK(nl_socket_modify_cb(sk, NL_CB_VALID, NL_CB_CUSTOM, survey_airtime_handler, result) == 0);
 	CHECK(msg = nlmsg_alloc());
 
-	/* device does not exist */
-	if (!(ifx = if_nametoindex(interface))){
-		error = -1;
-		goto out;
-	}
-
 	/* TODO: check return? */
 	genlmsg_put(msg, 0, 0, ctrl, 0, NLM_F_DUMP, NL80211_CMD_GET_SURVEY, 0);
 
@@ -144,10 +133,3 @@ out:
 
 	return error;
 }
-
-struct airtime* get_airtime(const char *wifi_0_dev, const char *wifi_1_dev) {
-	get_airtime_for_interface(&cur_airtime.radio0, wifi_0_dev);
-	get_airtime_for_interface(&cur_airtime.radio1, wifi_1_dev);
-
-	return &cur_airtime;
-}
diff --git a/package/gluon-airtime/src/airtime.h b/package/gluon-airtime/src/airtime.h
index c0c8bb93..c7c5fbb9 100644
--- a/package/gluon-airtime/src/airtime.h
+++ b/package/gluon-airtime/src/airtime.h
@@ -11,9 +11,4 @@ struct airtime_result {
 	uint8_t  noise;
 };
 
-struct airtime {
-	struct airtime_result radio0;
-	struct airtime_result radio1;
-};
-
-struct airtime* get_airtime(const char *radio0, const char *radio1);
+int get_airtime(struct airtime_result *result, int ifx);
diff --git a/package/gluon-airtime/src/ifaces.c b/package/gluon-airtime/src/ifaces.c
new file mode 100644
index 00000000..cbb9ff18
--- /dev/null
+++ b/package/gluon-airtime/src/ifaces.c
@@ -0,0 +1,66 @@
+#include <sys/socket.h>
+#include <linux/nl80211.h>
+#include <netlink/netlink.h>
+#include <netlink/genl/genl.h>
+#include <netlink/genl/ctrl.h>
+#include <net/if.h>
+#include <stdlib.h>
+
+#include "ifaces.h"
+
+static int iface_dump_handler(struct nl_msg *msg, struct iface_list **arg) {
+	struct nlattr *tb[NL80211_ATTR_MAX + 1];
+	struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
+	int wiphy;
+	struct iface_list **last_next;
+
+	nla_parse(tb, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0), genlmsg_attrlen(gnlh, 0), NULL);
+
+	wiphy = nla_get_u32(tb[NL80211_ATTR_WIPHY]);
+	for (last_next = arg; *last_next != NULL; last_next = &(*last_next)->next) {
+		if ((*last_next)->wiphy == wiphy)
+			goto abort;
+	}
+	*last_next = malloc(sizeof(**last_next));
+	(*last_next)->next = NULL;
+	(*last_next)->ifx = nla_get_u32(tb[NL80211_ATTR_IFINDEX]);
+	(*last_next)->wiphy = wiphy;
+
+abort:
+	return NL_SKIP;
+}
+
+struct iface_list *get_ifaces() {
+	int ctrl;
+	struct nl_sock *sk = NULL;
+	struct nl_msg *msg = NULL;
+	struct iface_list *ifaces = NULL;
+
+#define CHECK(x) { if (!(x)) { fprintf(stderr, "airtime.c: error on line %d\n",  __LINE__); goto out; } }
+
+	CHECK(sk = nl_socket_alloc());
+	CHECK(genl_connect(sk) >= 0);
+
+	CHECK(ctrl = genl_ctrl_resolve(sk, NL80211_GENL_NAME));
+	CHECK(nl_socket_modify_cb(sk, NL_CB_VALID, NL_CB_CUSTOM, (nl_recvmsg_msg_cb_t) iface_dump_handler, &ifaces) == 0);
+	CHECK(msg = nlmsg_alloc());
+
+	/* TODO: check return? */
+	genlmsg_put(msg, 0, 0, ctrl, 0, NLM_F_DUMP, NL80211_CMD_GET_INTERFACE, 0);
+
+	CHECK(nl_send_auto_complete(sk, msg) >= 0);
+	CHECK(nl_recvmsgs_default(sk) >= 0);
+
+#undef CHECK
+
+	return ifaces;
+
+out:
+	if (msg)
+		nlmsg_free(msg);
+
+	if (sk)
+		nl_socket_free(sk);
+
+	return NULL;
+}
diff --git a/package/gluon-airtime/src/ifaces.h b/package/gluon-airtime/src/ifaces.h
new file mode 100644
index 00000000..ea13ee34
--- /dev/null
+++ b/package/gluon-airtime/src/ifaces.h
@@ -0,0 +1,9 @@
+#pragma once
+
+struct iface_list {
+	int ifx;
+	int wiphy;
+	struct iface_list *next;
+};
+
+struct iface_list *get_ifaces();
diff --git a/package/gluon-airtime/src/respondd.c b/package/gluon-airtime/src/respondd.c
index cc4c0497..d4c0a511 100644
--- a/package/gluon-airtime/src/respondd.c
+++ b/package/gluon-airtime/src/respondd.c
@@ -4,9 +4,7 @@
 #include <respondd.h>
 
 #include "airtime.h"
-
-static const char const *wifi_0_dev = "client0";
-static const char const *wifi_1_dev = "client1";
+#include "ifaces.h"
 
 void fill_airtime_json(struct airtime_result *air, struct json_object *wireless) {
 	struct json_object *obj = NULL;
@@ -26,12 +24,10 @@ void fill_airtime_json(struct airtime_result *air, struct json_object *wireless)
 }
 
 static struct json_object *respondd_provider_statistics(void) {
-	struct airtime *airtime = NULL;
+	struct airtime_result airtime;
 	struct json_object *result, *wireless;
-
-	airtime = get_airtime(wifi_0_dev, wifi_1_dev);
-	if (!airtime)
-		return NULL;
+	struct iface_list *ifaces;
+	void *freeptr;
 
 	result = json_object_new_object();
 	if (!result)
@@ -43,11 +39,14 @@ static struct json_object *respondd_provider_statistics(void) {
 		return NULL;
 	}
 
-	if (airtime->radio0.frequency)
-		fill_airtime_json(&airtime->radio0, wireless);
-
-	if (airtime->radio1.frequency)
-		fill_airtime_json(&airtime->radio1, wireless);
+	ifaces = get_ifaces();
+	while (ifaces != NULL) {
+		get_airtime(&airtime, ifaces->ifx);
+		fill_airtime_json(&airtime, wireless);
+		freeptr = ifaces;
+		ifaces = ifaces->next;
+		free(freeptr);
+	}
 
 	json_object_object_add(result, "wireless", wireless);
 	return result;