summaryrefslogtreecommitdiff
path: root/drivers/net/ovpn/main.c
AgeCommit message (Collapse)Author
2025-05-15ovpn: don't drop skb's dst when xmitting packetAntonio Quartulli
When routing a packet to a LAN behind a peer, ovpn needs to inspect the route entry that brought the packet there in the first place. If this packet is truly routable, the route entry provides the GW to be used when looking up the VPN peer to send the packet to. However, the route entry is currently dropped before entering the ovpn xmit function, because the IFF_XMIT_DST_RELEASE priv_flag is enabled by default. Clear the IFF_XMIT_DST_RELEASE flag during interface setup to allow the route entry (skb's dst) to survive and thus be inspected by the ovpn routing logic. Fixes: a3aaef8cd173 ("ovpn: implement peer lookup logic") Reported-by: Gert Doering <gert@greenie.muc.de> Closes: https://github.com/OpenVPN/ovpn-net-next/issues/2 Tested-by: Gert Doering <gert@greenie.muc.de> Acked-by: Gert Doering <gert@greenie.muc.de> # as a primary user Link: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg31583.html Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
2025-04-17ovpn: add basic ethtool supportAntonio Quartulli
Implement support for basic ethtool functionality. Note that ovpn is a virtual device driver, therefore various ethtool APIs are just not meaningful and thus not implemented. Signed-off-by: Antonio Quartulli <antonio@openvpn.net> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Link: https://patch.msgid.link/20250415-b4-ovpn-v26-22-577f6097b964@openvpn.net Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-17ovpn: implement keepalive mechanismAntonio Quartulli
OpenVPN supports configuring a periodic keepalive packet. message to allow the remote endpoint detect link failures. This change implements the keepalive sending and timer expiring logic. Signed-off-by: Antonio Quartulli <antonio@openvpn.net> Link: https://patch.msgid.link/20250415-b4-ovpn-v26-16-577f6097b964@openvpn.net Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-17ovpn: implement multi-peer supportAntonio Quartulli
With this change an ovpn instance will be able to stay connected to multiple remote endpoints. This functionality is strictly required when running ovpn on an OpenVPN server. Signed-off-by: Antonio Quartulli <antonio@openvpn.net> Link: https://patch.msgid.link/20250415-b4-ovpn-v26-14-577f6097b964@openvpn.net Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-17ovpn: implement TCP transportAntonio Quartulli
With this change ovpn is allowed to communicate to peers also via TCP. Parsing of incoming messages is implemented through the strparser API. Note that ovpn redefines sk_prot and sk_socket->ops for the TCP socket used to communicate with the peer. For this reason it needs to access inet6_stream_ops, which is declared as extern in the IPv6 module, but it is not fully exported. Therefore this patch is also adding EXPORT_SYMBOL_GPL(inet6_stream_ops) to net/ipv6/af_inet6.c. Cc: David Ahern <dsahern@kernel.org> Cc: Eric Dumazet <edumazet@google.com> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Simon Horman <horms@kernel.org> Signed-off-by: Antonio Quartulli <antonio@openvpn.net> Link: https://patch.msgid.link/20250415-b4-ovpn-v26-11-577f6097b964@openvpn.net Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-17ovpn: implement basic RX path (UDP)Antonio Quartulli
Packets received over the socket are forwarded to the user device. Implementation is UDP only. TCP will be added by a later patch. Note: no decryption/decapsulation exists yet, packets are forwarded as they arrive without much processing. Signed-off-by: Antonio Quartulli <antonio@openvpn.net> Link: https://patch.msgid.link/20250415-b4-ovpn-v26-8-577f6097b964@openvpn.net Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-17ovpn: introduce the ovpn_socket objectAntonio Quartulli
This specific structure is used in the ovpn kernel module to wrap and carry around a standard kernel socket. ovpn takes ownership of passed sockets and therefore an ovpn specific objects is attached to them for status tracking purposes. Initially only UDP support is introduced. TCP will come in a later patch. Cc: willemdebruijn.kernel@gmail.com Signed-off-by: Antonio Quartulli <antonio@openvpn.net> Link: https://patch.msgid.link/20250415-b4-ovpn-v26-6-577f6097b964@openvpn.net Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-17ovpn: introduce the ovpn_peer objectAntonio Quartulli
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> Link: https://patch.msgid.link/20250415-b4-ovpn-v26-5-577f6097b964@openvpn.net Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-17ovpn: keep carrier always on for MP interfacesAntonio Quartulli
An ovpn interface configured in MP mode will keep carrier always on and let the user decide when to bring it administratively up and down. This way a MP node (i.e. a server) will keep its interface always up and running, even when no peer is connected. Signed-off-by: Antonio Quartulli <antonio@openvpn.net> Link: https://patch.msgid.link/20250415-b4-ovpn-v26-4-577f6097b964@openvpn.net Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-17ovpn: add basic interface creation/destruction/management routinesAntonio Quartulli
Add basic infrastructure for handling ovpn interfaces. Tested-by: Donald Hunter <donald.hunter@gmail.com> Signed-off-by: Antonio Quartulli <antonio@openvpn.net> Link: https://patch.msgid.link/20250415-b4-ovpn-v26-3-577f6097b964@openvpn.net Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-17ovpn: add basic netlink supportAntonio Quartulli
This commit introduces basic netlink support with family registration/unregistration functionalities and stub pre/post-doit. More importantly it introduces the YAML uAPI description along with its auto-generated files: - include/uapi/linux/ovpn.h - drivers/net/ovpn/netlink-gen.c - drivers/net/ovpn/netlink-gen.h Reviewed-by: Donald Hunter <donald.hunter@gmail.com> Signed-off-by: Antonio Quartulli <antonio@openvpn.net> Link: https://patch.msgid.link/20250415-b4-ovpn-v26-2-577f6097b964@openvpn.net Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-17net: introduce OpenVPN Data Channel Offload (ovpn)Antonio Quartulli
OpenVPN is a userspace software existing since around 2005 that allows users to create secure tunnels. So far OpenVPN has implemented all operations in userspace, which implies several back and forth between kernel and user land in order to process packets (encapsulate/decapsulate, encrypt/decrypt, rerouting..). With `ovpn` we intend to move the fast path (data channel) entirely in kernel space and thus improve user measured throughput over the tunnel. `ovpn` is implemented as a simple virtual network device driver, that can be manipulated by means of the standard RTNL APIs. A device of kind `ovpn` allows only IPv4/6 traffic and can be of type: * P2P (peer-to-peer): any packet sent over the interface will be encapsulated and transmitted to the other side (typical OpenVPN client or peer-to-peer behaviour); * P2MP (point-to-multipoint): packets sent over the interface are transmitted to peers based on existing routes (typical OpenVPN server behaviour). After the interface has been created, OpenVPN in userspace can configure it using a new Netlink API. Specifically it is possible to manage peers and their keys. The OpenVPN control channel is multiplexed over the same transport socket by means of OP codes. Anything that is not DATA_V2 (OpenVPN OP code for data traffic) is sent to userspace and handled there. This way the `ovpn` codebase is kept as compact as possible while focusing on handling data traffic only (fast path). Any OpenVPN control feature (like cipher negotiation, TLS handshake, rekeying, etc.) is still fully handled by the userspace process. When userspace establishes a new connection with a peer, it first performs the handshake and then passes the socket to the `ovpn` kernel module, which takes ownership. From this moment on `ovpn` will handle data traffic for the new peer. When control packets are received on the link, they are forwarded to userspace through the same transport socket they were received on, as userspace is still listening to them. Some events (like peer deletion) are sent to a Netlink multicast group. Although it wasn't easy to convince the community, `ovpn` implements only a limited number of the data-channel features supported by the userspace program. Each feature that made it to `ovpn` was attentively vetted to avoid carrying too much legacy along with us (and to give a clear cut to old and probalby-not-so-useful features). Notably, only encryption using AEAD ciphers (specifically ChaCha20Poly1305 and AES-GCM) was implemented. Supporting any other cipher out there was not deemed useful. Both UDP and TCP sockets are supported. As explained above, in case of P2MP mode, OpenVPN will use the main system routing table to decide which packet goes to which peer. This implies that no routing table was re-implemented in the `ovpn` kernel module. This kernel module can be enabled by selecting the CONFIG_OVPN entry in the networking drivers section. NOTE: this first patch introduces the very basic framework only. Features are then added patch by patch, however, although each patch will compile and possibly not break at runtime, only after having applied the full set it is expected to see the ovpn module fully working. Cc: steffen.klassert@secunet.com Cc: antony.antony@secunet.com Signed-off-by: Antonio Quartulli <antonio@openvpn.net> Link: https://patch.msgid.link/20250415-b4-ovpn-v26-1-577f6097b964@openvpn.net Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Paolo Abeni <pabeni@redhat.com>