batman-adv: netlink: add gateway table queries

Add BATADV_CMD_GET_GATEWAYS commands, using handlers bat_gw_dump in
batadv_algo_ops. Will always return -EOPNOTSUPP for now, as no
implementations exist yet.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

1 files changed, 59 insertions, 0 deletions

diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
index a77a17939f1e..c2928c2287b8 100644
--- a/net/batman-adv/gateway_client.c
+++ b/net/batman-adv/gateway_client.c
@@ -20,6 +20,7 @@
 
 #include <linux/atomic.h>
 #include <linux/byteorder/generic.h>
+#include <linux/errno.h>
 #include <linux/etherdevice.h>
 #include <linux/fs.h>
 #include <linux/if_ether.h>
@@ -31,6 +32,7 @@
 #include <linux/kref.h>
 #include <linux/list.h>
 #include <linux/netdevice.h>
+#include <linux/netlink.h>
 #include <linux/rculist.h>
 #include <linux/rcupdate.h>
 #include <linux/seq_file.h>
@@ -39,13 +41,17 @@
 #include <linux/spinlock.h>
 #include <linux/stddef.h>
 #include <linux/udp.h>
+#include <net/sock.h>
+#include <uapi/linux/batman_adv.h>
 
 #include "gateway_common.h"
 #include "hard-interface.h"
 #include "log.h"
+#include "netlink.h"
 #include "originator.h"
 #include "packet.h"
 #include "routing.h"
+#include "soft-interface.h"
 #include "sysfs.h"
 #include "translation-table.h"
 
@@ -501,6 +507,59 @@ int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset)
 }
 
 /**
+ * batadv_gw_dump - Dump gateways into a message
+ * @msg: Netlink message to dump into
+ * @cb: Control block containing additional options
+ *
+ * Return: Error code, or length of message
+ */
+int batadv_gw_dump(struct sk_buff *msg, struct netlink_callback *cb)
+{
+	struct batadv_hard_iface *primary_if = NULL;
+	struct net *net = sock_net(cb->skb->sk);
+	struct net_device *soft_iface;
+	struct batadv_priv *bat_priv;
+	int ifindex;
+	int ret;
+
+	ifindex = batadv_netlink_get_ifindex(cb->nlh,
+					     BATADV_ATTR_MESH_IFINDEX);
+	if (!ifindex)
+		return -EINVAL;
+
+	soft_iface = dev_get_by_index(net, ifindex);
+	if (!soft_iface || !batadv_softif_is_valid(soft_iface)) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	bat_priv = netdev_priv(soft_iface);
+
+	primary_if = batadv_primary_if_get_selected(bat_priv);
+	if (!primary_if || primary_if->if_status != BATADV_IF_ACTIVE) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	if (!bat_priv->algo_ops->gw.dump) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
+	bat_priv->algo_ops->gw.dump(msg, cb, bat_priv);
+
+	ret = msg->len;
+
+out:
+	if (primary_if)
+		batadv_hardif_put(primary_if);
+	if (soft_iface)
+		dev_put(soft_iface);
+
+	return ret;
+}
+
+/**
  * batadv_gw_dhcp_recipient_get - check if a packet is a DHCP message
  * @skb: the packet to check
  * @header_len: a pointer to the batman-adv header size