netdev - [PATCH net-next v3 05/24] ovpn: implement interface creation/destruction via netlink

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Message-ID: <20240506011637.27272-6-antonio@openvpn.net>
Date: Mon,  6 May 2024 03:16:18 +0200
From: Antonio Quartulli <antonio@...nvpn.net>
To: netdev@...r.kernel.org
Cc: Jakub Kicinski <kuba@...nel.org>,
	Sergey Ryazanov <ryazanov.s.a@...il.com>,
	Paolo Abeni <pabeni@...hat.com>,
	Eric Dumazet <edumazet@...gle.com>,
	Andrew Lunn <andrew@...n.ch>,
	Esben Haabendal <esben@...nix.com>,
	Antonio Quartulli <antonio@...nvpn.net>
Subject: [PATCH net-next v3 05/24] ovpn: implement interface creation/destruction via netlink

Allow userspace to create and destroy an interface using netlink
commands.

Signed-off-by: Antonio Quartulli <antonio@...nvpn.net>
---
 drivers/net/ovpn/main.h    |  2 ++
 drivers/net/ovpn/netlink.c | 55 ++++++++++++++++++++++++++++++++++++--
 2 files changed, 55 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ovpn/main.h b/drivers/net/ovpn/main.h
index 21d6bfb27d67..12b8d7e4a0fe 100644
--- a/drivers/net/ovpn/main.h
+++ b/drivers/net/ovpn/main.h
@@ -10,6 +10,8 @@
 #ifndef _NET_OVPN_MAIN_H_
 #define _NET_OVPN_MAIN_H_
 
+#define OVPN_DEFAULT_IFNAME "ovpn%d"
+
 /**
  * ovpn_iface_create - create and initialize a new 'ovpn' netdevice
  * @name: the name of the new device
diff --git a/drivers/net/ovpn/netlink.c b/drivers/net/ovpn/netlink.c
index c0a9f58e0e87..66f5c6fbe8e4 100644
--- a/drivers/net/ovpn/netlink.c
+++ b/drivers/net/ovpn/netlink.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/netdevice.h>
+#include <linux/rtnetlink.h>
 #include <net/genetlink.h>
 
 #include <uapi/linux/ovpn.h>
@@ -78,12 +79,62 @@ void ovpn_nl_post_doit(const struct genl_split_ops *ops, struct sk_buff *skb,
 
 int ovpn_nl_new_iface_doit(struct sk_buff *skb, struct genl_info *info)
 {
-	return -ENOTSUPP;
+	const char *ifname = OVPN_DEFAULT_IFNAME;
+	enum ovpn_mode mode = OVPN_MODE_P2P;
+	struct net_device *dev;
+	struct sk_buff *msg;
+	void *hdr;
+
+	if (info->attrs[OVPN_A_IFNAME])
+		ifname = nla_data(info->attrs[OVPN_A_IFNAME]);
+
+	if (info->attrs[OVPN_A_MODE]) {
+		mode = nla_get_u32(info->attrs[OVPN_A_MODE]);
+		pr_debug("ovpn: setting device (%s) mode: %u\n", ifname, mode);
+	}
+
+	dev = ovpn_iface_create(ifname, mode, genl_info_net(info));
+	if (IS_ERR(dev)) {
+		pr_err("ovpn: error while creating interface %s: %ld\n", ifname,
+		       PTR_ERR(dev));
+		return PTR_ERR(dev);
+	}
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, &ovpn_nl_family,
+			  0, OVPN_CMD_NEW_IFACE);
+	if (!hdr) {
+		netdev_err(dev, "%s: cannot create message header\n", __func__);
+		return -EMSGSIZE;
+	}
+
+	if (nla_put(msg, OVPN_A_IFNAME, strlen(dev->name) + 1, dev->name)) {
+		netdev_err(dev, "%s: cannot add ifname to reply\n", __func__);
+		genlmsg_cancel(msg, hdr);
+		nlmsg_free(msg);
+		return -EMSGSIZE;
+	}
+
+	genlmsg_end(msg, hdr);
+
+	return genlmsg_reply(msg, info);
 }
 
 int ovpn_nl_del_iface_doit(struct sk_buff *skb, struct genl_info *info)
 {
-	return -ENOTSUPP;
+	struct ovpn_struct *ovpn = info->user_ptr[0];
+
+	rtnl_lock();
+	ovpn_iface_destruct(ovpn);
+	dev_put(ovpn->dev);
+	rtnl_unlock();
+
+	synchronize_net();
+
+	return 0;
 }
 
 int ovpn_nl_set_peer_doit(struct sk_buff *skb, struct genl_info *info)
-- 
2.43.2