Re: [PATCH net-next v9 04/23] ovpn: add basic interface creation/destruction/management routines

Add basic infrastructure for handling ovpn interfaces.

Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
---
drivers/net/ovpn/main.c       | 115 ++++++++++++++++++++++++++++++++++++++++--
drivers/net/ovpn/main.h       |   7 +++
drivers/net/ovpn/ovpnstruct.h |   8 +++
drivers/net/ovpn/packet.h     |  40 +++++++++++++++
include/uapi/linux/if_link.h  |  15 ++++++
5 files changed, 180 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ovpn/main.c b/drivers/net/ovpn/main.c
index d5bdb0055f4dd3a6e32dc6e792bed1e7fd59e101..eead7677b8239eb3c48bb26ca95492d88512b8d4 100644
--- a/drivers/net/ovpn/main.c
+++ b/drivers/net/ovpn/main.c

@@ -10,18 +10,52 @@

#include <linux/genetlink.h>
#include <linux/module.h>
#include <linux/netdevice.h>
+#include <linux/inetdevice.h>
+#include <net/ip.h>
#include <net/rtnetlink.h>
-#include <uapi/linux/ovpn.h>
+#include <uapi/linux/if_arp.h>

#include "ovpnstruct.h"
#include "main.h"
#include "netlink.h"
#include "io.h"
+#include "packet.h"

/* Driver info */
#define DRV_DESCRIPTION	"OpenVPN data channel offload (ovpn)"
#define DRV_COPYRIGHT	"(C) 2020-2024 OpenVPN, Inc."

+static void ovpn_struct_free(struct net_device *net)
+{
+}
+
+static int ovpn_net_open(struct net_device *dev)
+{
+	netif_tx_start_all_queues(dev);
+	return 0;
+}
+
+static int ovpn_net_stop(struct net_device *dev)
+{
+	netif_tx_stop_all_queues(dev);
+	return 0;
+}
+
+static const struct net_device_ops ovpn_netdev_ops = {
+	.ndo_open		= ovpn_net_open,
+	.ndo_stop		= ovpn_net_stop,
+	.ndo_start_xmit		= ovpn_net_xmit,
+};
+
+static const struct device_type ovpn_type = {
+	.name = OVPN_FAMILY_NAME,
+};
+
+static const struct nla_policy ovpn_policy[IFLA_OVPN_MAX + 1] = {
+	[IFLA_OVPN_MODE] = NLA_POLICY_RANGE(NLA_U8, OVPN_MODE_P2P,
+					    OVPN_MODE_MP),
+};
+
/**
 * ovpn_dev_is_valid - check if the netdevice is of type 'ovpn'
 * @dev: the interface to check

@@ -33,16 +67,76 @@ bool ovpn_dev_is_valid(const struct net_device *dev)

	return dev->netdev_ops->ndo_start_xmit == ovpn_net_xmit;
}

+static void ovpn_setup(struct net_device *dev)
+{
+	/* compute the overhead considering AEAD encryption */
+	const int overhead = sizeof(u32) + NONCE_WIRE_SIZE + 16 +
+			     sizeof(struct udphdr) +
+			     max(sizeof(struct ipv6hdr), sizeof(struct iphdr));
+
+	netdev_features_t feat = NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_RXCSUM |
+				 NETIF_F_GSO | NETIF_F_GSO_SOFTWARE |
+				 NETIF_F_HIGHDMA;
+
+	dev->needs_free_netdev = true;
+
+	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
+
+	dev->netdev_ops = &ovpn_netdev_ops;
+
+	dev->priv_destructor = ovpn_struct_free;
+
+	dev->hard_header_len = 0;
+	dev->addr_len = 0;
+	dev->mtu = ETH_DATA_LEN - overhead;
+	dev->min_mtu = IPV4_MIN_MTU;
+	dev->max_mtu = IP_MAX_MTU - overhead;
+
+	dev->type = ARPHRD_NONE;
+	dev->flags = IFF_POINTOPOINT | IFF_NOARP;
+	dev->priv_flags |= IFF_NO_QUEUE;
+
+	dev->lltx = true;
+	dev->features |= feat;
+	dev->hw_features |= feat;
+	dev->hw_enc_features |= feat;
+
+	dev->needed_headroom = OVPN_HEAD_ROOM;
+	dev->needed_tailroom = OVPN_MAX_PADDING;
+
+	SET_NETDEV_DEVTYPE(dev, &ovpn_type);
+}
+
static int ovpn_newlink(struct net *src_net, struct net_device *dev,
			struct nlattr *tb[], struct nlattr *data[],
			struct netlink_ext_ack *extack)
{
-	return -EOPNOTSUPP;
+	struct ovpn_struct *ovpn = netdev_priv(dev);
+	enum ovpn_mode mode = OVPN_MODE_P2P;
+
+	if (data && data[IFLA_OVPN_MODE]) {
+		mode = nla_get_u8(data[IFLA_OVPN_MODE]);

+		netdev_dbg(dev, "setting device mode: %u\n", mode);
+	}
+
+	ovpn->dev = dev;
+	ovpn->mode = mode;
+
+	/* turn carrier explicitly off after registration, this way state is
+	 * clearly defined
+	 */
+	netif_carrier_off(dev);
+
+	return register_netdevice(dev);