[PATCH 1/2] monitor: Use genl APIs instead of open coding

[Denis Kenzior <denkenz@gmail.com>]

l_genl class has nice ways of discovering and requesting families.  The
genl functionality has been added after the iwmon skeleton was created,
but it is now time to migrate to using these APIs.
---
 monitor/main.c | 93 ++++++--------------------------------------------
 1 file changed, 11 insertions(+), 82 deletions(-)

diff --git a/monitor/main.c b/monitor/main.c
index 8f354d52607d..32f5ec4fc7f3 100644
--- a/monitor/main.c
+++ b/monitor/main.c
@@ -224,110 +224,39 @@ struct iwmon_interface {
 	char *ifname;
 	bool exists;
 	struct l_netlink *rtnl;
-	struct l_netlink *genl;
+	struct l_genl *genl;
 	struct l_io *io;
 };
 
 static struct iwmon_interface monitor_interface = { };
 
-static void genl_parse(uint16_t type, const void *data, uint32_t len,
-							const char *ifname)
+static void nl80211_appeared(const struct l_genl_family_info *info,
+					void *user_data)
 {
-	const struct genlmsghdr *genlmsg = data;
-	const struct nlattr *nla;
-	char name[GENL_NAMSIZ];
-	uint16_t id = 0;
-
-	if (nlmon)
-		return;
-
-	if (type != GENL_ID_CTRL)
-		return;
-
-	if (genlmsg->cmd != CTRL_CMD_NEWFAMILY)
-		return;
-
-	for (nla = data + GENL_HDRLEN; NLA_OK(nla, len);
-						nla = NLA_NEXT(nla, len)) {
-		switch (nla->nla_type & NLA_TYPE_MASK) {
-		case CTRL_ATTR_FAMILY_ID:
-			id = *((uint16_t *) NLA_DATA(nla));
-			break;
-		case CTRL_ATTR_FAMILY_NAME:
-			strncpy(name, NLA_DATA(nla), GENL_NAMSIZ - 1);
-			break;
-		}
-	}
-
-	if (id == 0)
-		return;
-
-	if (strcmp(name, NL80211_GENL_NAME))
-		return;
+	const char *ifname = user_data;
 
 	monitor_interface.io = open_packet(ifname);
 	if (!monitor_interface.io)
 		goto failed;
 
-	nlmon = nlmon_open(id, writer_path, &config);
+	nlmon = nlmon_open(l_genl_family_info_get_id(info),
+						writer_path, &config);
 	if (!nlmon)
 		goto failed;
 
 	l_io_set_read_handler(monitor_interface.io, nlmon_receive, nlmon, NULL);
-
 	return;
 
 failed:
 	l_main_quit();
 }
 
-static void genl_notify(uint16_t type, const void *data,
-						uint32_t len, void *user_data)
-{
-	const char *ifname = user_data;
-
-	genl_parse(type, data, len, ifname);
-}
-
-static void genl_callback(int error, uint16_t type, const void *data,
-						uint32_t len, void *user_data)
-{
-	const char *ifname = user_data;
-
-	if (error < 0) {
-		fprintf(stderr, "Failed to lookup nl80211 family\n");
-		l_main_quit();
-		return;
-	}
-
-	genl_parse(type, data, len, ifname);
-}
-
-static struct l_netlink *genl_lookup(const char *ifname)
+static struct l_genl *genl_lookup(const char *ifname)
 {
-	struct l_netlink *genl;
-	char buf[GENL_HDRLEN + NLA_HDRLEN + GENL_NAMSIZ];
-	struct genlmsghdr *genlmsg;
-	struct nlattr *nla;
-
-	genl = l_netlink_new(NETLINK_GENERIC);
-
-	l_netlink_register(genl, GENL_ID_CTRL, genl_notify, NULL, NULL);
-
-	genlmsg = (struct genlmsghdr *) buf;
-	genlmsg->cmd = CTRL_CMD_GETFAMILY;
-	genlmsg->version = 0;
-	genlmsg->reserved = 0;
-
-	nla = (struct nlattr *) (buf + GENL_HDRLEN);
-	nla->nla_len = NLA_HDRLEN + GENL_NAMSIZ;
-	nla->nla_type = CTRL_ATTR_FAMILY_NAME;
-	strncpy(buf + GENL_HDRLEN + NLA_HDRLEN,
-					NL80211_GENL_NAME, GENL_NAMSIZ);
-
-	l_netlink_send(genl, GENL_ID_CTRL, 0, buf, sizeof(buf),
-					genl_callback, (char *) ifname, NULL);
+	struct l_genl *genl = l_genl_new();
 
+	l_genl_request_family(genl, NL80211_GENL_NAME, nl80211_appeared,
+					(char *) ifname, NULL);
 	return genl;
 }
 
@@ -957,7 +886,7 @@ int main(int argc, char *argv[])
 
 	l_io_destroy(monitor_interface.io);
 	l_netlink_destroy(monitor_interface.rtnl);
-	l_netlink_destroy(monitor_interface.genl);
+	l_genl_unref(monitor_interface.genl);
 	l_free(monitor_interface.ifname);
 
 	nlmon_close(nlmon);
-- 
2.45.2