diff mbox series

[net-next,v11,06/23] ovpn: introduce the ovpn_peer object

Message ID 20241029-b4-ovpn-v11-6-de4698c73a25@openvpn.net (mailing list archive)
State New
Delegated to: Netdev Maintainers
Headers show
Series Introducing OpenVPN Data Channel Offload | expand

Checks

Context Check Description
netdev/series_format fail Series longer than 15 patches
netdev/tree_selection success Clearly marked for net-next, async
netdev/ynl fail Tree is dirty after regen; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5 this patch: 5
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 2 maintainers not CCed: andrew+netdev@lunn.ch openvpn-devel@lists.sourceforge.net
netdev/build_clang success Errors and warnings before: 4 this patch: 4
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 8 this patch: 8
netdev/checkpatch warning WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Antonio Quartulli Oct. 29, 2024, 10:47 a.m. UTC
An ovpn_peer object holds the whole status of a remote peer
(regardless whether it is a server or a client).

This includes status for crypto, tx/rx buffers, napi, etc.

Only support for one peer is introduced (P2P mode).
Multi peer support is introduced with a later patch.

Along with the ovpn_peer, also the ovpn_bind object is introcued
as the two are strictly related.
An ovpn_bind object wraps a sockaddr representing the local
coordinates being used to talk to a specific peer.

Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
---
 drivers/net/ovpn/Makefile     |   2 +
 drivers/net/ovpn/bind.c       |  58 +++++++
 drivers/net/ovpn/bind.h       | 117 ++++++++++++++
 drivers/net/ovpn/main.c       |  11 ++
 drivers/net/ovpn/main.h       |   2 +
 drivers/net/ovpn/ovpnstruct.h |   4 +
 drivers/net/ovpn/peer.c       | 354 ++++++++++++++++++++++++++++++++++++++++++
 drivers/net/ovpn/peer.h       |  79 ++++++++++
 8 files changed, 627 insertions(+)

Comments

Sabrina Dubroca Oct. 30, 2024, 4:37 p.m. UTC | #1
2024-10-29, 11:47:19 +0100, Antonio Quartulli wrote:
> +static void ovpn_peer_release(struct ovpn_peer *peer)
> +{
> +	ovpn_bind_reset(peer, NULL);
> +
> +	dst_cache_destroy(&peer->dst_cache);

Is it safe to destroy the cache at this time? In the same function, we
use rcu to free the peer, but AFAICT the dst_cache will be freed
immediately:

void dst_cache_destroy(struct dst_cache *dst_cache)
{
[...]
	free_percpu(dst_cache->cache);
}

(probably no real issue because ovpn_udp_send_skb gets called while we
hold a reference to the peer?)

> +	netdev_put(peer->ovpn->dev, &peer->ovpn->dev_tracker);
> +	kfree_rcu(peer, rcu);
> +}


[...]
> +static int ovpn_peer_del_p2p(struct ovpn_peer *peer,
> +			     enum ovpn_del_peer_reason reason)
> +	__must_hold(&peer->ovpn->lock)
> +{
> +	struct ovpn_peer *tmp;
> +
> +	tmp = rcu_dereference_protected(peer->ovpn->peer,
> +					lockdep_is_held(&peer->ovpn->lock));
> +	if (tmp != peer) {
> +		DEBUG_NET_WARN_ON_ONCE(1);
> +		if (tmp)
> +			ovpn_peer_put(tmp);

Does peer->ovpn->peer need to be set to NULL here as well? Or is it
going to survive this _put?

> +
> +		return -ENOENT;
> +	}
> +
> +	tmp->delete_reason = reason;
> +	RCU_INIT_POINTER(peer->ovpn->peer, NULL);
> +	ovpn_peer_put(tmp);
> +
> +	return 0;
> +}
Antonio Quartulli Oct. 30, 2024, 8:47 p.m. UTC | #2
On 30/10/2024 17:37, Sabrina Dubroca wrote:
> 2024-10-29, 11:47:19 +0100, Antonio Quartulli wrote:
>> +static void ovpn_peer_release(struct ovpn_peer *peer)
>> +{
>> +	ovpn_bind_reset(peer, NULL);
>> +
>> +	dst_cache_destroy(&peer->dst_cache);
> 
> Is it safe to destroy the cache at this time? In the same function, we
> use rcu to free the peer, but AFAICT the dst_cache will be freed
> immediately:
> 
> void dst_cache_destroy(struct dst_cache *dst_cache)
> {
> [...]
> 	free_percpu(dst_cache->cache);
> }
> 
> (probably no real issue because ovpn_udp_send_skb gets called while we
> hold a reference to the peer?)

Right.
That was my assumption: release happens on refcnt = 0 only, therefore no 
field should be in use anymore.
Anything that may still be in use will have its own refcounter.

> 
>> +	netdev_put(peer->ovpn->dev, &peer->ovpn->dev_tracker);
>> +	kfree_rcu(peer, rcu);
>> +}
> 
> 
> [...]
>> +static int ovpn_peer_del_p2p(struct ovpn_peer *peer,
>> +			     enum ovpn_del_peer_reason reason)
>> +	__must_hold(&peer->ovpn->lock)
>> +{
>> +	struct ovpn_peer *tmp;
>> +
>> +	tmp = rcu_dereference_protected(peer->ovpn->peer,
>> +					lockdep_is_held(&peer->ovpn->lock));
>> +	if (tmp != peer) {
>> +		DEBUG_NET_WARN_ON_ONCE(1);
>> +		if (tmp)
>> +			ovpn_peer_put(tmp);
> 
> Does peer->ovpn->peer need to be set to NULL here as well? Or is it
> going to survive this _put?

First of all consider that this is truly something that we don't expect 
to happen (hence the WARN_ON).
If this is happening it's because we are trying to delete a peer that is 
not the one we are connected to (unexplainable scenario in p2p mode).

Still, should we hit this case (I truly can't see how), I'd say "leave 
everything as is - maybe this call was just a mistake".

Cheers,

> 
>> +
>> +		return -ENOENT;
>> +	}
>> +
>> +	tmp->delete_reason = reason;
>> +	RCU_INIT_POINTER(peer->ovpn->peer, NULL);
>> +	ovpn_peer_put(tmp);
>> +
>> +	return 0;
>> +}
>
diff mbox series

Patch

diff --git a/drivers/net/ovpn/Makefile b/drivers/net/ovpn/Makefile
index 201dc001419f1d99ae95c0ee0f96e68f8a4eac16..ce13499b3e1775a7f2a9ce16c6cb0aa088f93685 100644
--- a/drivers/net/ovpn/Makefile
+++ b/drivers/net/ovpn/Makefile
@@ -7,7 +7,9 @@ 
 # Author:	Antonio Quartulli <antonio@openvpn.net>
 
 obj-$(CONFIG_OVPN) := ovpn.o
+ovpn-y += bind.o
 ovpn-y += main.o
 ovpn-y += io.o
 ovpn-y += netlink.o
 ovpn-y += netlink-gen.o
+ovpn-y += peer.o
diff --git a/drivers/net/ovpn/bind.c b/drivers/net/ovpn/bind.c
new file mode 100644
index 0000000000000000000000000000000000000000..b4d2ccec2ceddf43bc445b489cc62a578ef0ad0a
--- /dev/null
+++ b/drivers/net/ovpn/bind.c
@@ -0,0 +1,58 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*  OpenVPN data channel offload
+ *
+ *  Copyright (C) 2012-2024 OpenVPN, Inc.
+ *
+ *  Author:	James Yonan <james@openvpn.net>
+ *		Antonio Quartulli <antonio@openvpn.net>
+ */
+
+#include <linux/netdevice.h>
+#include <linux/socket.h>
+
+#include "ovpnstruct.h"
+#include "bind.h"
+#include "peer.h"
+
+/**
+ * ovpn_bind_from_sockaddr - retrieve binding matching sockaddr
+ * @ss: the sockaddr to match
+ *
+ * Return: the bind matching the passed sockaddr if found, NULL otherwise
+ */
+struct ovpn_bind *ovpn_bind_from_sockaddr(const struct sockaddr_storage *ss)
+{
+	struct ovpn_bind *bind;
+	size_t sa_len;
+
+	if (ss->ss_family == AF_INET)
+		sa_len = sizeof(struct sockaddr_in);
+	else if (ss->ss_family == AF_INET6)
+		sa_len = sizeof(struct sockaddr_in6);
+	else
+		return ERR_PTR(-EAFNOSUPPORT);
+
+	bind = kzalloc(sizeof(*bind), GFP_ATOMIC);
+	if (unlikely(!bind))
+		return ERR_PTR(-ENOMEM);
+
+	memcpy(&bind->remote, ss, sa_len);
+
+	return bind;
+}
+
+/**
+ * ovpn_bind_reset - assign new binding to peer
+ * @peer: the peer whose binding has to be replaced
+ * @new: the new bind to assign
+ */
+void ovpn_bind_reset(struct ovpn_peer *peer, struct ovpn_bind *new)
+{
+	struct ovpn_bind *old;
+
+	spin_lock_bh(&peer->lock);
+	old = rcu_replace_pointer(peer->bind, new, true);
+	spin_unlock_bh(&peer->lock);
+
+	kfree_rcu(old, rcu);
+}
diff --git a/drivers/net/ovpn/bind.h b/drivers/net/ovpn/bind.h
new file mode 100644
index 0000000000000000000000000000000000000000..859213d5040deb36c416eafcf5c6ab31c4d52c7a
--- /dev/null
+++ b/drivers/net/ovpn/bind.h
@@ -0,0 +1,117 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*  OpenVPN data channel offload
+ *
+ *  Copyright (C) 2012-2024 OpenVPN, Inc.
+ *
+ *  Author:	James Yonan <james@openvpn.net>
+ *		Antonio Quartulli <antonio@openvpn.net>
+ */
+
+#ifndef _NET_OVPN_OVPNBIND_H_
+#define _NET_OVPN_OVPNBIND_H_
+
+#include <net/ip.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/rcupdate.h>
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
+
+struct ovpn_peer;
+
+/**
+ * union ovpn_sockaddr - basic transport layer address
+ * @in4: IPv4 address
+ * @in6: IPv6 address
+ */
+union ovpn_sockaddr {
+	struct sockaddr_in in4;
+	struct sockaddr_in6 in6;
+};
+
+/**
+ * struct ovpn_bind - remote peer binding
+ * @remote: the remote peer sockaddress
+ * @local: local endpoint used to talk to the peer
+ * @local.ipv4: local IPv4 used to talk to the peer
+ * @local.ipv6: local IPv6 used to talk to the peer
+ * @rcu: used to schedule RCU cleanup job
+ */
+struct ovpn_bind {
+	union ovpn_sockaddr remote;  /* remote sockaddr */
+
+	union {
+		struct in_addr ipv4;
+		struct in6_addr ipv6;
+	} local;
+
+	struct rcu_head rcu;
+};
+
+/**
+ * skb_protocol_to_family - translate skb->protocol to AF_INET or AF_INET6
+ * @skb: the packet sk_buff to inspect
+ *
+ * Return: AF_INET, AF_INET6 or 0 in case of unknown protocol
+ */
+static inline unsigned short skb_protocol_to_family(const struct sk_buff *skb)
+{
+	switch (skb->protocol) {
+	case htons(ETH_P_IP):
+		return AF_INET;
+	case htons(ETH_P_IPV6):
+		return AF_INET6;
+	default:
+		return 0;
+	}
+}
+
+/**
+ * ovpn_bind_skb_src_match - match packet source with binding
+ * @bind: the binding to match
+ * @skb: the packet to match
+ *
+ * Return: true if the packet source matches the remote peer sockaddr
+ * in the binding
+ */
+static inline bool ovpn_bind_skb_src_match(const struct ovpn_bind *bind,
+					   const struct sk_buff *skb)
+{
+	const unsigned short family = skb_protocol_to_family(skb);
+	const union ovpn_sockaddr *remote;
+
+	if (unlikely(!bind))
+		return false;
+
+	remote = &bind->remote;
+
+	if (unlikely(remote->in4.sin_family != family))
+		return false;
+
+	switch (family) {
+	case AF_INET:
+		if (unlikely(remote->in4.sin_addr.s_addr != ip_hdr(skb)->saddr))
+			return false;
+
+		if (unlikely(remote->in4.sin_port != udp_hdr(skb)->source))
+			return false;
+		break;
+	case AF_INET6:
+		if (unlikely(!ipv6_addr_equal(&remote->in6.sin6_addr,
+					      &ipv6_hdr(skb)->saddr)))
+			return false;
+
+		if (unlikely(remote->in6.sin6_port != udp_hdr(skb)->source))
+			return false;
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+struct ovpn_bind *ovpn_bind_from_sockaddr(const struct sockaddr_storage *sa);
+void ovpn_bind_reset(struct ovpn_peer *peer, struct ovpn_bind *bind);
+
+#endif /* _NET_OVPN_OVPNBIND_H_ */
diff --git a/drivers/net/ovpn/main.c b/drivers/net/ovpn/main.c
index eaa83a8662e4ac2c758201008268f9633643c0b6..5492ce07751d135c1484fe1ed8227c646df94969 100644
--- a/drivers/net/ovpn/main.c
+++ b/drivers/net/ovpn/main.c
@@ -20,6 +20,7 @@ 
 #include "netlink.h"
 #include "io.h"
 #include "packet.h"
+#include "peer.h"
 
 /* Driver info */
 #define DRV_DESCRIPTION	"OpenVPN data channel offload (ovpn)"
@@ -29,6 +30,11 @@  static void ovpn_struct_free(struct net_device *net)
 {
 }
 
+static int ovpn_net_init(struct net_device *dev)
+{
+	return 0;
+}
+
 static int ovpn_net_open(struct net_device *dev)
 {
 	/* ovpn keeps the carrier always on to avoid losing IP or route
@@ -49,6 +55,7 @@  static int ovpn_net_stop(struct net_device *dev)
 }
 
 static const struct net_device_ops ovpn_netdev_ops = {
+	.ndo_init		= ovpn_net_init,
 	.ndo_open		= ovpn_net_open,
 	.ndo_stop		= ovpn_net_stop,
 	.ndo_start_xmit		= ovpn_net_xmit,
@@ -128,6 +135,7 @@  static int ovpn_newlink(struct net *src_net, struct net_device *dev,
 
 	ovpn->dev = dev;
 	ovpn->mode = mode;
+	spin_lock_init(&ovpn->lock);
 
 	/* turn carrier explicitly off after registration, this way state is
 	 * clearly defined
@@ -176,6 +184,9 @@  static int ovpn_netdev_notifier_call(struct notifier_block *nb,
 
 		netif_carrier_off(dev);
 		ovpn->registered = false;
+
+		if (ovpn->mode == OVPN_MODE_P2P)
+			ovpn_peer_release_p2p(ovpn);
 		break;
 	case NETDEV_POST_INIT:
 	case NETDEV_GOING_DOWN:
diff --git a/drivers/net/ovpn/main.h b/drivers/net/ovpn/main.h
index 0740a05070a817e0daea7b63a1f4fcebd274eb37..28e5c44816e110974333a7a6a9cf18bd15ae84e6 100644
--- a/drivers/net/ovpn/main.h
+++ b/drivers/net/ovpn/main.h
@@ -19,4 +19,6 @@  bool ovpn_dev_is_valid(const struct net_device *dev);
 #define OVPN_HEAD_ROOM ALIGN(16 + SKB_HEADER_LEN, 4)
 #define OVPN_MAX_PADDING 16
 
+#define OVPN_QUEUE_LEN 1024
+
 #endif /* _NET_OVPN_MAIN_H_ */
diff --git a/drivers/net/ovpn/ovpnstruct.h b/drivers/net/ovpn/ovpnstruct.h
index 211df871538d34fdff90d182f21a0b0fb11b28ad..a22c5083381c131db01a28c0f51e661d690d4998 100644
--- a/drivers/net/ovpn/ovpnstruct.h
+++ b/drivers/net/ovpn/ovpnstruct.h
@@ -20,6 +20,8 @@ 
  * @dev_tracker: reference tracker for associated dev
  * @registered: whether dev is still registered with netdev or not
  * @mode: device operation mode (i.e. p2p, mp, ..)
+ * @lock: protect this object
+ * @peer: in P2P mode, this is the only remote peer
  * @dev_list: entry for the module wide device list
  */
 struct ovpn_struct {
@@ -27,6 +29,8 @@  struct ovpn_struct {
 	netdevice_tracker dev_tracker;
 	bool registered;
 	enum ovpn_mode mode;
+	spinlock_t lock; /* protect writing to the ovpn_struct object */
+	struct ovpn_peer __rcu *peer;
 	struct list_head dev_list;
 };
 
diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c
new file mode 100644
index 0000000000000000000000000000000000000000..d9788a0cc99b5839c466c35d1b2266cc6b95fb72
--- /dev/null
+++ b/drivers/net/ovpn/peer.c
@@ -0,0 +1,354 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*  OpenVPN data channel offload
+ *
+ *  Copyright (C) 2020-2024 OpenVPN, Inc.
+ *
+ *  Author:	James Yonan <james@openvpn.net>
+ *		Antonio Quartulli <antonio@openvpn.net>
+ */
+
+#include <linux/skbuff.h>
+#include <linux/list.h>
+
+#include "ovpnstruct.h"
+#include "bind.h"
+#include "io.h"
+#include "main.h"
+#include "netlink.h"
+#include "peer.h"
+
+/**
+ * ovpn_peer_new - allocate and initialize a new peer object
+ * @ovpn: the openvpn instance inside which the peer should be created
+ * @id: the ID assigned to this peer
+ *
+ * Return: a pointer to the new peer on success or an error code otherwise
+ */
+struct ovpn_peer *ovpn_peer_new(struct ovpn_struct *ovpn, u32 id)
+{
+	struct ovpn_peer *peer;
+	int ret;
+
+	/* alloc and init peer object */
+	peer = kzalloc(sizeof(*peer), GFP_KERNEL);
+	if (!peer)
+		return ERR_PTR(-ENOMEM);
+
+	peer->id = id;
+	peer->halt = false;
+	peer->ovpn = ovpn;
+
+	peer->vpn_addrs.ipv4.s_addr = htonl(INADDR_ANY);
+	peer->vpn_addrs.ipv6 = in6addr_any;
+
+	RCU_INIT_POINTER(peer->bind, NULL);
+	spin_lock_init(&peer->lock);
+	kref_init(&peer->refcount);
+
+	ret = dst_cache_init(&peer->dst_cache, GFP_KERNEL);
+	if (ret < 0) {
+		netdev_err(ovpn->dev, "%s: cannot initialize dst cache\n",
+			   __func__);
+		kfree(peer);
+		return ERR_PTR(ret);
+	}
+
+	netdev_hold(ovpn->dev, &ovpn->dev_tracker, GFP_KERNEL);
+
+	return peer;
+}
+
+/**
+ * ovpn_peer_release - release peer private members
+ * @peer: the peer to release
+ */
+static void ovpn_peer_release(struct ovpn_peer *peer)
+{
+	ovpn_bind_reset(peer, NULL);
+
+	dst_cache_destroy(&peer->dst_cache);
+	netdev_put(peer->ovpn->dev, &peer->ovpn->dev_tracker);
+	kfree_rcu(peer, rcu);
+}
+
+/**
+ * ovpn_peer_release_kref - callback for kref_put
+ * @kref: the kref object belonging to the peer
+ */
+void ovpn_peer_release_kref(struct kref *kref)
+{
+	struct ovpn_peer *peer = container_of(kref, struct ovpn_peer, refcount);
+
+	ovpn_peer_release(peer);
+}
+
+/**
+ * ovpn_peer_skb_to_sockaddr - fill sockaddr with skb source address
+ * @skb: the packet to extract data from
+ * @ss: the sockaddr to fill
+ *
+ * Return: true on success or false otherwise
+ */
+static bool ovpn_peer_skb_to_sockaddr(struct sk_buff *skb,
+				      struct sockaddr_storage *ss)
+{
+	struct sockaddr_in6 *sa6;
+	struct sockaddr_in *sa4;
+
+	ss->ss_family = skb_protocol_to_family(skb);
+	switch (ss->ss_family) {
+	case AF_INET:
+		sa4 = (struct sockaddr_in *)ss;
+		sa4->sin_family = AF_INET;
+		sa4->sin_addr.s_addr = ip_hdr(skb)->saddr;
+		sa4->sin_port = udp_hdr(skb)->source;
+		break;
+	case AF_INET6:
+		sa6 = (struct sockaddr_in6 *)ss;
+		sa6->sin6_family = AF_INET6;
+		sa6->sin6_addr = ipv6_hdr(skb)->saddr;
+		sa6->sin6_port = udp_hdr(skb)->source;
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+/**
+ * ovpn_peer_transp_match - check if sockaddr and peer binding match
+ * @peer: the peer to get the binding from
+ * @ss: the sockaddr to match
+ *
+ * Return: true if sockaddr and binding match or false otherwise
+ */
+static bool ovpn_peer_transp_match(const struct ovpn_peer *peer,
+				   const struct sockaddr_storage *ss)
+{
+	struct ovpn_bind *bind = rcu_dereference(peer->bind);
+	struct sockaddr_in6 *sa6;
+	struct sockaddr_in *sa4;
+
+	if (unlikely(!bind))
+		return false;
+
+	if (ss->ss_family != bind->remote.in4.sin_family)
+		return false;
+
+	switch (ss->ss_family) {
+	case AF_INET:
+		sa4 = (struct sockaddr_in *)ss;
+		if (sa4->sin_addr.s_addr != bind->remote.in4.sin_addr.s_addr)
+			return false;
+		if (sa4->sin_port != bind->remote.in4.sin_port)
+			return false;
+		break;
+	case AF_INET6:
+		sa6 = (struct sockaddr_in6 *)ss;
+		if (!ipv6_addr_equal(&sa6->sin6_addr,
+				     &bind->remote.in6.sin6_addr))
+			return false;
+		if (sa6->sin6_port != bind->remote.in6.sin6_port)
+			return false;
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+/**
+ * ovpn_peer_get_by_transp_addr_p2p - get peer by transport address in a P2P
+ *                                    instance
+ * @ovpn: the openvpn instance to search
+ * @ss: the transport socket address
+ *
+ * Return: the peer if found or NULL otherwise
+ */
+static struct ovpn_peer *
+ovpn_peer_get_by_transp_addr_p2p(struct ovpn_struct *ovpn,
+				 struct sockaddr_storage *ss)
+{
+	struct ovpn_peer *tmp, *peer = NULL;
+
+	rcu_read_lock();
+	tmp = rcu_dereference(ovpn->peer);
+	if (likely(tmp && ovpn_peer_transp_match(tmp, ss) &&
+		   ovpn_peer_hold(tmp)))
+		peer = tmp;
+	rcu_read_unlock();
+
+	return peer;
+}
+
+/**
+ * ovpn_peer_get_by_transp_addr - retrieve peer by transport address
+ * @ovpn: the openvpn instance to search
+ * @skb: the skb to retrieve the source transport address from
+ *
+ * Return: a pointer to the peer if found or NULL otherwise
+ */
+struct ovpn_peer *ovpn_peer_get_by_transp_addr(struct ovpn_struct *ovpn,
+					       struct sk_buff *skb)
+{
+	struct ovpn_peer *peer = NULL;
+	struct sockaddr_storage ss = { 0 };
+
+	if (unlikely(!ovpn_peer_skb_to_sockaddr(skb, &ss)))
+		return NULL;
+
+	if (ovpn->mode == OVPN_MODE_P2P)
+		peer = ovpn_peer_get_by_transp_addr_p2p(ovpn, &ss);
+
+	return peer;
+}
+
+/**
+ * ovpn_peer_get_by_id_p2p - get peer by ID in a P2P instance
+ * @ovpn: the openvpn instance to search
+ * @peer_id: the ID of the peer to find
+ *
+ * Return: the peer if found or NULL otherwise
+ */
+static struct ovpn_peer *ovpn_peer_get_by_id_p2p(struct ovpn_struct *ovpn,
+						 u32 peer_id)
+{
+	struct ovpn_peer *tmp, *peer = NULL;
+
+	rcu_read_lock();
+	tmp = rcu_dereference(ovpn->peer);
+	if (likely(tmp && tmp->id == peer_id && ovpn_peer_hold(tmp)))
+		peer = tmp;
+	rcu_read_unlock();
+
+	return peer;
+}
+
+/**
+ * ovpn_peer_get_by_id - retrieve peer by ID
+ * @ovpn: the openvpn instance to search
+ * @peer_id: the unique peer identifier to match
+ *
+ * Return: a pointer to the peer if found or NULL otherwise
+ */
+struct ovpn_peer *ovpn_peer_get_by_id(struct ovpn_struct *ovpn, u32 peer_id)
+{
+	struct ovpn_peer *peer = NULL;
+
+	if (ovpn->mode == OVPN_MODE_P2P)
+		peer = ovpn_peer_get_by_id_p2p(ovpn, peer_id);
+
+	return peer;
+}
+
+/**
+ * ovpn_peer_add_p2p - add peer to related tables in a P2P instance
+ * @ovpn: the instance to add the peer to
+ * @peer: the peer to add
+ *
+ * Return: 0 on success or a negative error code otherwise
+ */
+static int ovpn_peer_add_p2p(struct ovpn_struct *ovpn, struct ovpn_peer *peer)
+{
+	struct ovpn_peer *tmp;
+
+	spin_lock_bh(&ovpn->lock);
+	/* in p2p mode it is possible to have a single peer only, therefore the
+	 * old one is released and substituted by the new one
+	 */
+	tmp = rcu_dereference_protected(ovpn->peer,
+					lockdep_is_held(&ovpn->lock));
+	if (tmp) {
+		tmp->delete_reason = OVPN_DEL_PEER_REASON_TEARDOWN;
+		ovpn_peer_put(tmp);
+	}
+
+	rcu_assign_pointer(ovpn->peer, peer);
+	spin_unlock_bh(&ovpn->lock);
+
+	return 0;
+}
+
+/**
+ * ovpn_peer_add - add peer to the related tables
+ * @ovpn: the openvpn instance the peer belongs to
+ * @peer: the peer object to add
+ *
+ * Assume refcounter was increased by caller
+ *
+ * Return: 0 on success or a negative error code otherwise
+ */
+int ovpn_peer_add(struct ovpn_struct *ovpn, struct ovpn_peer *peer)
+{
+	switch (ovpn->mode) {
+	case OVPN_MODE_P2P:
+		return ovpn_peer_add_p2p(ovpn, peer);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+/**
+ * ovpn_peer_del_p2p - delete peer from related tables in a P2P instance
+ * @peer: the peer to delete
+ * @reason: reason why the peer was deleted (sent to userspace)
+ *
+ * Return: 0 on success or a negative error code otherwise
+ */
+static int ovpn_peer_del_p2p(struct ovpn_peer *peer,
+			     enum ovpn_del_peer_reason reason)
+	__must_hold(&peer->ovpn->lock)
+{
+	struct ovpn_peer *tmp;
+
+	tmp = rcu_dereference_protected(peer->ovpn->peer,
+					lockdep_is_held(&peer->ovpn->lock));
+	if (tmp != peer) {
+		DEBUG_NET_WARN_ON_ONCE(1);
+		if (tmp)
+			ovpn_peer_put(tmp);
+
+		return -ENOENT;
+	}
+
+	tmp->delete_reason = reason;
+	RCU_INIT_POINTER(peer->ovpn->peer, NULL);
+	ovpn_peer_put(tmp);
+
+	return 0;
+}
+
+/**
+ * ovpn_peer_release_p2p - release peer upon P2P device teardown
+ * @ovpn: the instance being torn down
+ */
+void ovpn_peer_release_p2p(struct ovpn_struct *ovpn)
+{
+	struct ovpn_peer *tmp;
+
+	spin_lock_bh(&ovpn->lock);
+	tmp = rcu_dereference_protected(ovpn->peer,
+					lockdep_is_held(&ovpn->lock));
+	if (tmp)
+		ovpn_peer_del_p2p(tmp, OVPN_DEL_PEER_REASON_TEARDOWN);
+	spin_unlock_bh(&ovpn->lock);
+}
+
+/**
+ * ovpn_peer_del - delete peer from related tables
+ * @peer: the peer object to delete
+ * @reason: reason for deleting peer (will be sent to userspace)
+ *
+ * Return: 0 on success or a negative error code otherwise
+ */
+int ovpn_peer_del(struct ovpn_peer *peer, enum ovpn_del_peer_reason reason)
+{
+	switch (peer->ovpn->mode) {
+	case OVPN_MODE_P2P:
+		return ovpn_peer_del_p2p(peer, reason);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
diff --git a/drivers/net/ovpn/peer.h b/drivers/net/ovpn/peer.h
new file mode 100644
index 0000000000000000000000000000000000000000..6e0c6b14559de886d0677117f5a7ae029214e1f8
--- /dev/null
+++ b/drivers/net/ovpn/peer.h
@@ -0,0 +1,79 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* OpenVPN data channel offload
+ *
+ *  Copyright (C) 2020-2024 OpenVPN, Inc.
+ *
+ *  Author:	James Yonan <james@openvpn.net>
+ *		Antonio Quartulli <antonio@openvpn.net>
+ */
+
+#ifndef _NET_OVPN_OVPNPEER_H_
+#define _NET_OVPN_OVPNPEER_H_
+
+#include <net/dst_cache.h>
+
+/**
+ * struct ovpn_peer - the main remote peer object
+ * @ovpn: main openvpn instance this peer belongs to
+ * @id: unique identifier
+ * @vpn_addrs: IP addresses assigned over the tunnel
+ * @vpn_addrs.ipv4: IPv4 assigned to peer on the tunnel
+ * @vpn_addrs.ipv6: IPv6 assigned to peer on the tunnel
+ * @dst_cache: cache for dst_entry used to send to peer
+ * @bind: remote peer binding
+ * @halt: true if ovpn_peer_mark_delete was called
+ * @delete_reason: why peer was deleted (i.e. timeout, transport error, ..)
+ * @lock: protects binding to peer (bind)
+ * @refcount: reference counter
+ * @rcu: used to free peer in an RCU safe way
+ * @delete_work: deferred cleanup work, used to notify userspace
+ */
+struct ovpn_peer {
+	struct ovpn_struct *ovpn;
+	u32 id;
+	struct {
+		struct in_addr ipv4;
+		struct in6_addr ipv6;
+	} vpn_addrs;
+	struct dst_cache dst_cache;
+	struct ovpn_bind __rcu *bind;
+	bool halt;
+	enum ovpn_del_peer_reason delete_reason;
+	spinlock_t lock; /* protects bind */
+	struct kref refcount;
+	struct rcu_head rcu;
+	struct work_struct delete_work;
+};
+
+/**
+ * ovpn_peer_hold - increase reference counter
+ * @peer: the peer whose counter should be increased
+ *
+ * Return: true if the counter was increased or false if it was zero already
+ */
+static inline bool ovpn_peer_hold(struct ovpn_peer *peer)
+{
+	return kref_get_unless_zero(&peer->refcount);
+}
+
+void ovpn_peer_release_kref(struct kref *kref);
+
+/**
+ * ovpn_peer_put - decrease reference counter
+ * @peer: the peer whose counter should be decreased
+ */
+static inline void ovpn_peer_put(struct ovpn_peer *peer)
+{
+	kref_put(&peer->refcount, ovpn_peer_release_kref);
+}
+
+struct ovpn_peer *ovpn_peer_new(struct ovpn_struct *ovpn, u32 id);
+int ovpn_peer_add(struct ovpn_struct *ovpn, struct ovpn_peer *peer);
+int ovpn_peer_del(struct ovpn_peer *peer, enum ovpn_del_peer_reason reason);
+void ovpn_peer_release_p2p(struct ovpn_struct *ovpn);
+
+struct ovpn_peer *ovpn_peer_get_by_transp_addr(struct ovpn_struct *ovpn,
+					       struct sk_buff *skb);
+struct ovpn_peer *ovpn_peer_get_by_id(struct ovpn_struct *ovpn, u32 peer_id);
+
+#endif /* _NET_OVPN_OVPNPEER_H_ */