[PATCH net-next v9 21/23] ovpn: notify userspace when a peer is deleted

Antonio Quartulli
2024-10-16T01:04:27Z

Whenever a peer is deleted, send a notification to userspace so that it
can react accordingly.

This is most important when a peer is deleted due to ping timeout,
because it all happens in kernelspace and thus userspace has no direct
way to learn about it.

Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
---
drivers/net/ovpn/netlink.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++
drivers/net/ovpn/netlink.h | 1 +
drivers/net/ovpn/peer.c | 1 +
3 files changed, 57 insertions(+)

diff --git a/drivers/net/ovpn/netlink.c b/drivers/net/ovpn/netlink.c
index 09c7df2b1c76c812a3bece6e63c9fac13c96c327..975d324c0362e34fc209eaa4552051ff75c00036 100644
--- a/drivers/net/ovpn/netlink.c
+++ b/drivers/net/ovpn/netlink.c
@@ -903,6 +903,61 @@ int ovpn_nl_key_del_doit(struct sk_buff *skb, struct genl_info *info)
return 0;
}

+/**
+ * ovpn_nl_peer_del_notify - notify userspace about peer being deleted
+ * @peer: the peer being deleted
+ *
+ * Return: 0 on success or a negative error code otherwise
+ */
+int ovpn_nl_peer_del_notify(struct ovpn_peer *peer)
+{
+ struct sk_buff *msg;
+ struct nlattr *attr;
+ int ret = -EMSGSIZE;
+ void *hdr;
+
+ netdev_info(peer->ovpn->dev, "deleting peer with id %u, reason %d\n",
+ peer->id, peer->delete_reason);
+
+ msg = nlmsg_new(100, GFP_ATOMIC);
+ if (!msg)
+ return -ENOMEM;
+
+ hdr = genlmsg_put(msg, 0, 0, &ovpn_nl_family, 0, OVPN_CMD_PEER_DEL_NTF);
+ if (!hdr) {
+ ret = -ENOBUFS;
+ goto err_free_msg;
+ }
+
+ if (nla_put_u32(msg, OVPN_A_IFINDEX, peer->ovpn->dev->ifindex))
+ goto err_cancel_msg;
+
+ attr = nla_nest_start(msg, OVPN_A_PEER);
+ if (!attr)
+ goto err_cancel_msg;
+
+ if (nla_put_u8(msg, OVPN_A_PEER_DEL_REASON, peer->delete_reason))
+ goto err_cancel_msg;
+
+ if (nla_put_u32(msg, OVPN_A_PEER_ID, peer->id))
+ goto err_cancel_msg;
+
+ nla_nest_end(msg, attr);
+
+ genlmsg_end(msg, hdr);
+
+ genlmsg_multicast_netns(&ovpn_nl_family, dev_net(peer->ovpn->dev), msg,
+ 0, OVPN_NLGRP_PEERS, GFP_ATOMIC);
+
+ return 0;
+
+err_cancel_msg:
+ genlmsg_cancel(msg, hdr);
+err_free_msg:
+ nlmsg_free(msg);
+ return ret;
+}
+
/**
* ovpn_nl_key_swap_notify - notify userspace peer's key must be renewed
* @peer: the peer whose key needs to be renewed
diff --git a/drivers/net/ovpn/netlink.h b/drivers/net/ovpn/netlink.h
index 33390b13c8904d40b629662005a9eb92ff617c3b..4ab3abcf23dba11f6b92e3d69e700693adbc671b 100644
--- a/drivers/net/ovpn/netlink.h
+++ b/drivers/net/ovpn/netlink.h
@@ -12,6 +12,7 @@
int ovpn_nl_register(void);
void ovpn_nl_unregister(void);

+int ovpn_nl_peer_del_notify(struct ovpn_peer *peer);
int ovpn_nl_key_swap_notify(struct ovpn_peer *peer, u8 key_id);

#endif /* _NET_OVPN_NETLINK_H_ */
diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c
index 2e218e8cfacad753d1284808958234913f3ef59e..267ffa17db632d3b959c5b53f80075966f95a53c 100644
--- a/drivers/net/ovpn/peer.c
+++ b/drivers/net/ovpn/peer.c
@@ -239,6 +239,7 @@ void ovpn_peer_release_kref(struct kref *kref)
{
struct ovpn_peer *peer = container_of(kref, struct ovpn_peer, refcount);

+ ovpn_nl_peer_del_notify(peer);
ovpn_peer_release(peer);
}

--
2.45.2