Message-ID: <20250306230203.1550314-6-nikolay@enfabrica.net>
Date: Fri,  7 Mar 2025 01:01:55 +0200
From: Nikolay Aleksandrov <nikolay@...abrica.net>
To: netdev@...r.kernel.org
Cc: shrijeet@...abrica.net,
	alex.badea@...sight.com,
	eric.davis@...adcom.com,
	rip.sohan@....com,
	dsahern@...nel.org,
	bmt@...ich.ibm.com,
	roland@...abrica.net,
	nikolay@...abrica.net,
	winston.liu@...sight.com,
	dan.mihailescu@...sight.com,
	kheib@...hat.com,
	parth.v.parikh@...sight.com,
	davem@...hat.com,
	ian.ziemba@....com,
	andrew.tauferner@...nelisnetworks.com,
	welch@....com,
	rakhahari.bhunia@...sight.com,
	kingshuk.mandal@...sight.com,
	linux-rdma@...r.kernel.org,
	kuba@...nel.org,
	pabeni@...hat.com
Subject: [RFC PATCH 05/13] drivers: ultraeth: add tunnel udp device support

Add UE UDP tunnel device (uecon) which is created for each context. It will
be used to transmit and receive UE packets. Currently all packets are
dropped. A default port of 5432 will be used at context creation. It can be
changed at runtime when the net device is down.

Signed-off-by: Nikolay Aleksandrov <nikolay@...abrica.net>
Signed-off-by: Alex Badea <alex.badea@...sight.com>
---
 Documentation/netlink/specs/rt_link.yaml  |  14 +
 Documentation/netlink/specs/ultraeth.yaml |   6 +
 drivers/ultraeth/Makefile                 |   3 +-
 drivers/ultraeth/uecon.c                  | 311 ++++++++++++++++++++++
 drivers/ultraeth/uet_context.c            |  12 +-
 drivers/ultraeth/uet_main.c               |  19 +-
 include/net/ultraeth/uecon.h              |  28 ++
 include/net/ultraeth/uet_context.h        |   2 +-
 include/uapi/linux/if_link.h              |   8 +
 include/uapi/linux/ultraeth.h             |   1 +
 include/uapi/linux/ultraeth_nl.h          |   2 +
 11 files changed, 402 insertions(+), 4 deletions(-)
 create mode 100644 drivers/ultraeth/uecon.c
 create mode 100644 include/net/ultraeth/uecon.h

diff --git a/Documentation/netlink/specs/rt_link.yaml b/Documentation/netlink/specs/rt_link.yaml
index 31238455f8e9..747231b1fd6d 100644
--- a/Documentation/netlink/specs/rt_link.yaml
+++ b/Documentation/netlink/specs/rt_link.yaml
@@ -2272,6 +2272,17 @@ attribute-sets:
       -
         name: tailroom
         type: u16
+  -
+    name: linkinfo-uecon-attrs
+    name-prefix: ifla-uecon-
+    attributes:
+      -
+        name: context-id
+        type: u32
+      -
+        name: port
+        type: u16
+        byte-order: big-endian
 
 sub-messages:
   -
@@ -2322,6 +2333,9 @@ sub-messages:
       -
         value: netkit
         attribute-set: linkinfo-netkit-attrs
+      -
+        value: uecon
+        attribute-set: linkinfo-uecon-attrs
   -
     name: linkinfo-member-data-msg
     formats:
diff --git a/Documentation/netlink/specs/ultraeth.yaml b/Documentation/netlink/specs/ultraeth.yaml
index e95c73a36892..847f748efa52 100644
--- a/Documentation/netlink/specs/ultraeth.yaml
+++ b/Documentation/netlink/specs/ultraeth.yaml
@@ -16,6 +16,12 @@ attribute-sets:
         checks:
           min: 0
           max: 255
+      -
+        name: netdev-ifindex
+        type: s32
+      -
+        name: netdev-name
+        type: string
   -
     name: contexts
     attributes:
diff --git a/drivers/ultraeth/Makefile b/drivers/ultraeth/Makefile
index bf41a62273f9..0035023876ab 100644
--- a/drivers/ultraeth/Makefile
+++ b/drivers/ultraeth/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_ULTRAETH) += ultraeth.o
 
-ultraeth-objs := uet_main.o uet_context.o uet_netlink.o uet_job.o
+ultraeth-objs := uet_main.o uet_context.o uet_netlink.o uet_job.o \
+			uecon.o
diff --git a/drivers/ultraeth/uecon.c b/drivers/ultraeth/uecon.c
new file mode 100644
index 000000000000..4b74680700af
--- /dev/null
+++ b/drivers/ultraeth/uecon.c
@@ -0,0 +1,311 @@
+// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+
+#include <linux/etherdevice.h>
+#include <linux/if_link.h>
+#include <net/ipv6_stubs.h>
+#include <net/dst_metadata.h>
+#include <net/rtnetlink.h>
+#include <net/gro.h>
+#include <net/udp_tunnel.h>
+#include <net/ultraeth/uecon.h>
+#include <net/ultraeth/uet_context.h>
+
+static const struct nla_policy uecon_ndev_policy[IFLA_UECON_MAX + 1] = {
+	[IFLA_UECON_CONTEXT_ID]	= { .type = NLA_REJECT,
+				    .reject_message = "Domain id attribute is read-only" },
+	[IFLA_UECON_PORT]	= { .type = NLA_BE16 },
+};
+
+static netdev_tx_t uecon_ndev_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct uecon_ndev_priv *uecpriv = netdev_priv(dev);
+	struct ip_tunnel_info *info;
+	int err, min_headroom;
+	struct socket *sock;
+	struct rtable *rt;
+	bool use_cache;
+	__be32 saddr;
+	__be16 sport;
+
+	rcu_read_lock();
+	sock = rcu_dereference(uecpriv->sock);
+	if (!sock)
+		goto out_err;
+	info = skb_tunnel_info(skb);
+	if (!info)
+		goto out_err;
+	use_cache = ip_tunnel_dst_cache_usable(skb, info);
+	sport = uecpriv->udp_port;
+	rt = udp_tunnel_dst_lookup(skb, dev, dev_net(dev), 0, &saddr,
+				   &info->key, sport,
+				   info->key.tp_dst, info->key.tos,
+				   use_cache ? &info->dst_cache : NULL);
+	if (IS_ERR(rt)) {
+		if (PTR_ERR(rt) == -ELOOP)
+			dev->stats.collisions++;
+		else if (PTR_ERR(rt) == -ENETUNREACH)
+			dev->stats.tx_carrier_errors++;
+
+		goto out_err;
+	}
+
+	skb_tunnel_check_pmtu(skb, &rt->dst,
+			      sizeof(struct iphdr) + sizeof(struct udphdr),
+			      false);
+	skb_scrub_packet(skb, false);
+
+	min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len +
+		       sizeof(struct iphdr) + sizeof(struct udphdr);
+	err = skb_cow_head(skb, min_headroom);
+	if (unlikely(err)) {
+		dst_release(&rt->dst);
+		goto out_err;
+	}
+
+	err = udp_tunnel_handle_offloads(skb, false);
+	if (err) {
+		dst_release(&rt->dst);
+		goto out_err;
+	}
+
+	skb_reset_mac_header(skb);
+	skb_set_inner_protocol(skb, skb->protocol);
+
+	udp_tunnel_xmit_skb(rt, sock->sk, skb, saddr,
+			    info->key.u.ipv4.dst, info->key.tos,
+			    ip4_dst_hoplimit(&rt->dst), 0,
+			    sport, info->key.tp_dst,
+			    false, false);
+	rcu_read_unlock();
+
+	return NETDEV_TX_OK;
+
+out_err:
+	rcu_read_unlock();
+	dev_kfree_skb(skb);
+	dev->stats.tx_errors++;
+
+	return NETDEV_TX_OK;
+}
+
+static int uecon_ndev_encap_recv(struct sock *sk, struct sk_buff *skb)
+{
+	struct uecon_ndev_priv *uecpriv;
+	int len;
+
+	uecpriv = rcu_dereference_sk_user_data(sk);
+	if (!uecpriv)
+		goto drop;
+
+	if (skb->protocol != htons(ETH_P_IP))
+		goto drop;
+
+	/* we assume [ tnl ip hdr ] [ tnl udp hdr ] [ pdc hdr ] [ ses hdr ] */
+	if (iptunnel_pull_header(skb, sizeof(struct udphdr), htons(ETH_P_802_3), false))
+		goto drop_count;
+
+	skb_reset_mac_header(skb);
+	skb_reset_network_header(skb);
+	skb->pkt_type = PACKET_HOST;
+	skb->dev = uecpriv->dev;
+	len = skb->len;
+	consume_skb(skb);
+	dev_sw_netstats_rx_add(uecpriv->dev, len);
+
+	return 0;
+
+drop_count:
+	dev_core_stats_rx_dropped_inc(uecpriv->dev);
+drop:
+	kfree_skb(skb);
+	return 0;
+}
+
+static int uecon_ndev_err_lookup(struct sock *sk, struct sk_buff *skb)
+{
+	return 0;
+}
+
+static struct socket *uecon_ndev_create_sock(struct net_device *dev)
+{
+	struct uecon_ndev_priv *uecpriv = netdev_priv(dev);
+	struct udp_port_cfg udp_conf;
+	struct socket *sock;
+	int err;
+
+	memset(&udp_conf, 0, sizeof(udp_conf));
+	udp_conf.family = AF_INET;
+	udp_conf.local_udp_port = uecpriv->udp_port;
+	err = udp_sock_create(dev_net(dev), &udp_conf, &sock);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	udp_allow_gso(sock->sk);
+
+	return sock;
+}
+
+static int uecon_ndev_open(struct net_device *dev)
+{
+	struct uecon_ndev_priv *uecpriv = netdev_priv(dev);
+	struct udp_tunnel_sock_cfg tunnel_cfg;
+	struct socket *sock;
+
+	sock = uecon_ndev_create_sock(dev);
+	if (IS_ERR(sock))
+		return PTR_ERR(sock);
+	memset(&tunnel_cfg, 0, sizeof(tunnel_cfg));
+	tunnel_cfg.sk_user_data = uecpriv;
+	tunnel_cfg.encap_type = 1;
+	tunnel_cfg.encap_rcv = uecon_ndev_encap_recv;
+	tunnel_cfg.encap_err_lookup = uecon_ndev_err_lookup;
+	setup_udp_tunnel_sock(dev_net(dev), sock, &tunnel_cfg);
+
+	rcu_assign_pointer(uecpriv->sock, sock);
+
+	return 0;
+}
+
+static int uecon_ndev_stop(struct net_device *dev)
+{
+	struct uecon_ndev_priv *uecpriv = netdev_priv(dev);
+	struct socket *sock = rtnl_dereference(uecpriv->sock);
+
+	rcu_assign_pointer(uecpriv->sock, NULL);
+	synchronize_rcu();
+	udp_tunnel_sock_release(sock);
+
+	return 0;
+}
+
+const struct net_device_ops uecon_netdev_ops = {
+	.ndo_open		= uecon_ndev_open,
+	.ndo_stop		= uecon_ndev_stop,
+	.ndo_start_xmit		= uecon_ndev_xmit,
+	.ndo_get_stats64	= dev_get_tstats64,
+};
+
+static const struct device_type uecon_ndev_type = {
+	.name = "uecon",
+};
+
+static void uecon_ndev_setup(struct net_device *dev)
+{
+	struct uecon_ndev_priv *uecpriv = netdev_priv(dev);
+
+	dev->netdev_ops = &uecon_netdev_ops;
+	SET_NETDEV_DEVTYPE(dev, &uecon_ndev_type);
+
+	dev->features |= NETIF_F_VLAN_CHALLENGED | NETIF_F_SG | NETIF_F_HW_CSUM;
+	dev->features |= NETIF_F_FRAGLIST | NETIF_F_RXCSUM | NETIF_F_GSO_SOFTWARE;
+
+	dev->hw_features |= NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_FRAGLIST;
+	dev->hw_features |= NETIF_F_RXCSUM | NETIF_F_GSO_SOFTWARE;
+
+	dev->priv_flags |= IFF_NO_QUEUE;
+
+	dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
+	dev->type = ARPHRD_NONE;
+
+	dev->min_mtu = IPV4_MIN_MTU;
+	/* No header for the time being, account for it later */
+	dev->max_mtu = IP_MAX_MTU;
+	dev->mtu = ETH_DATA_LEN;
+	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
+
+	netif_keep_dst(dev);
+	uecpriv->dev = dev;
+}
+
+static int uecon_ndev_changelink(struct net_device *dev, struct nlattr *tb[],
+				 struct nlattr *data[],
+				 struct netlink_ext_ack *extack)
+{
+	if (dev->flags & IFF_UP) {
+		NL_SET_ERR_MSG_MOD(extack, "Cannot change uecon settings while the device is up");
+		return -EBUSY;
+	}
+
+	if (tb[IFLA_UECON_PORT]) {
+		struct uecon_ndev_priv *uecpriv = netdev_priv(dev);
+
+		uecpriv->udp_port = nla_get_be16(tb[IFLA_UECON_PORT]);
+	}
+
+	return 0;
+}
+
+static size_t uecon_ndev_get_size(const struct net_device *dev)
+{
+	return nla_total_size(sizeof(__u32))  + /* IFLA_UECON_CONTEXT_ID */
+	       nla_total_size(sizeof(__be16)) + /* IFLA_UECON_PORT */
+	       0;
+}
+
+static int uecon_ndev_fill_info(struct sk_buff *skb, const struct net_device *dev)
+{
+	struct uecon_ndev_priv *uecpriv = netdev_priv(dev);
+
+	if (nla_put_u32(skb, IFLA_UECON_CONTEXT_ID, uecpriv->context->id) ||
+	    nla_put_be16(skb, IFLA_UECON_PORT, uecpriv->udp_port))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static struct rtnl_link_ops uecon_netdev_link_ops __read_mostly = {
+	.kind		= "uecon",
+	.priv_size	= sizeof(struct uecon_ndev_priv),
+	.setup		= uecon_ndev_setup,
+	.get_size	= uecon_ndev_get_size,
+	.fill_info	= uecon_ndev_fill_info,
+	.changelink	= uecon_ndev_changelink,
+	.policy		= uecon_ndev_policy,
+	.maxtype	= IFLA_UECON_MAX
+};
+
+int uecon_netdev_init(struct uet_context *ctx)
+{
+	struct net *net = current->nsproxy->net_ns;
+	struct uecon_ndev_priv *priv;
+	char ifname[IFNAMSIZ];
+	int ret;
+
+	snprintf(ifname, IFNAMSIZ, "uecon%d", ctx->id);
+	ctx->netdev = alloc_netdev(sizeof(struct uecon_ndev_priv), ifname,
+				   NET_NAME_PREDICTABLE, uecon_ndev_setup);
+	if (!ctx->netdev)
+		return -ENOMEM;
+	priv = netdev_priv(ctx->netdev);
+
+	priv->context = ctx;
+	priv->dev = ctx->netdev;
+	priv->udp_port = htons(UECON_DEFAULT_PORT);
+	ctx->netdev->rtnl_link_ops = &uecon_netdev_link_ops;
+	dev_net_set(ctx->netdev, net);
+
+	ret = register_netdev(ctx->netdev);
+	if (ret) {
+		free_netdev(ctx->netdev);
+		ctx->netdev = NULL;
+	}
+
+	return ret;
+}
+
+void uecon_netdev_uninit(struct uet_context *ctx)
+{
+	unregister_netdev(ctx->netdev);
+	free_netdev(ctx->netdev);
+	ctx->netdev = NULL;
+}
+
+int uecon_rtnl_link_register(void)
+{
+	return rtnl_link_register(&uecon_netdev_link_ops);
+}
+
+void uecon_rtnl_link_unregister(void)
+{
+	rtnl_link_unregister(&uecon_netdev_link_ops);
+}
diff --git a/drivers/ultraeth/uet_context.c b/drivers/ultraeth/uet_context.c
index 3d738c02e992..e0d276cb1942 100644
--- a/drivers/ultraeth/uet_context.c
+++ b/drivers/ultraeth/uet_context.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
 
 #include <net/ultraeth/uet_context.h>
+#include <net/ultraeth/uecon.h>
 #include "uet_netlink.h"
 
 #define MAX_CONTEXT_ID 256
@@ -106,10 +107,16 @@ int uet_context_create(int id)
 	if (err)
 		goto ctx_jobs_err;
 
+	err = uecon_netdev_init(ctx);
+	if (err)
+		goto ctx_netdev_err;
+
 	uet_context_link(ctx);
 
 	return 0;
 
+ctx_netdev_err:
+	uet_jobs_uninit(&ctx->job_reg);
 ctx_jobs_err:
 	uet_context_put_id(ctx);
 ctx_id_err:
@@ -121,6 +128,7 @@ int uet_context_create(int id)
 static void __uet_context_destroy(struct uet_context *ctx)
 {
 	uet_context_unlink(ctx);
+	uecon_netdev_uninit(ctx);
 	uet_jobs_uninit(&ctx->job_reg);
 	uet_context_put_id(ctx);
 	kfree(ctx);
@@ -166,7 +174,9 @@ static int __nl_ctx_fill_one(struct sk_buff *skb,
 	if (!hdr)
 		return -EMSGSIZE;
 
-	if (nla_put_s32(skb, ULTRAETH_A_CONTEXT_ID, ctx->id))
+	if (nla_put_s32(skb, ULTRAETH_A_CONTEXT_ID, ctx->id) ||
+	    nla_put_s32(skb, ULTRAETH_A_CONTEXT_NETDEV_IFINDEX, ctx->netdev->ifindex) ||
+	    nla_put_string(skb, ULTRAETH_A_CONTEXT_NETDEV_NAME, ctx->netdev->name))
 		goto out_err;
 
 	genlmsg_end(skb, hdr);
diff --git a/drivers/ultraeth/uet_main.c b/drivers/ultraeth/uet_main.c
index 0ec1dc74abbb..c37f65978ecf 100644
--- a/drivers/ultraeth/uet_main.c
+++ b/drivers/ultraeth/uet_main.c
@@ -4,18 +4,35 @@
 #include <linux/module.h>
 #include <linux/types.h>
 #include <net/ultraeth/uet_context.h>
+#include <net/ultraeth/uecon.h>
 
 #include "uet_netlink.h"
 
 static int __init uet_init(void)
 {
-	return genl_register_family(&ultraeth_nl_family);
+	int err;
+
+	err = genl_register_family(&ultraeth_nl_family);
+	if (err)
+		goto out_err;
+
+	err = uecon_rtnl_link_register();
+	if (err)
+		goto rtnl_link_err;
+
+	return 0;
+
+rtnl_link_err:
+	genl_unregister_family(&ultraeth_nl_family);
+out_err:
+	return err;
 }
 
 static void __exit uet_exit(void)
 {
 	genl_unregister_family(&ultraeth_nl_family);
 	uet_context_destroy_all();
+	uecon_rtnl_link_unregister();
 }
 
 module_init(uet_init);
diff --git a/include/net/ultraeth/uecon.h b/include/net/ultraeth/uecon.h
new file mode 100644
index 000000000000..6316a0557b1f
--- /dev/null
+++ b/include/net/ultraeth/uecon.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */
+
+#ifndef _UECON_H
+#define _UECON_H
+#include <net/ip_tunnels.h>
+
+#define UECON_DEFAULT_PORT 5432
+
+struct socket;
+struct net_device;
+
+struct uecon_ndev_priv {
+	struct uet_context *context;
+	struct socket __rcu *sock;
+	struct net_device *dev;
+	__be16 udp_port;
+};
+
+extern const struct net_device_ops uecon_netdev_ops;
+int uecon_netdev_init(struct uet_context *ctx);
+void uecon_netdev_uninit(struct uet_context *ctx);
+
+int uecon_rtnl_link_register(void);
+void uecon_rtnl_link_unregister(void);
+
+int uecon_netdev_register(void);
+void uecon_netdev_unregister(void);
+#endif /* _UECON_H */
diff --git a/include/net/ultraeth/uet_context.h b/include/net/ultraeth/uet_context.h
index 7638c768597e..8210f69a1571 100644
--- a/include/net/ultraeth/uet_context.h
+++ b/include/net/ultraeth/uet_context.h
@@ -17,6 +17,7 @@ struct uet_context {
 	wait_queue_head_t refcnt_wait;
 	struct list_head list;
 
+	struct net_device *netdev;
 	struct uet_job_registry job_reg;
 };
 
@@ -26,5 +27,4 @@ void uet_context_put(struct uet_context *ses_pl);
 int uet_context_create(int id);
 bool uet_context_destroy(int id);
 void uet_context_destroy_all(void);
-
 #endif /* _UET_CONTEXT_H */
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 318386cc5b0d..1ba189ecf9da 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -1986,4 +1986,12 @@ enum {
 
 #define IFLA_DSA_MAX	(__IFLA_DSA_MAX - 1)
 
+enum {
+	IFLA_UECON_UNSPEC,
+	IFLA_UECON_CONTEXT_ID,
+	IFLA_UECON_PORT,
+	__IFLA_UECON_MAX
+};
+
+#define IFLA_UECON_MAX (__IFLA_UECON_MAX - 1)
 #endif /* _UAPI_LINUX_IF_LINK_H */
diff --git a/include/uapi/linux/ultraeth.h b/include/uapi/linux/ultraeth.h
index a6f244de6d75..a4ac25455aa0 100644
--- a/include/uapi/linux/ultraeth.h
+++ b/include/uapi/linux/ultraeth.h
@@ -6,6 +6,7 @@
 #include <asm/byteorder.h>
 #include <linux/types.h>
 
+#define UET_DEFAULT_PORT 5432
 #define UET_SVC_MAX_LEN 64
 
 enum {
diff --git a/include/uapi/linux/ultraeth_nl.h b/include/uapi/linux/ultraeth_nl.h
index d65521de196a..515044022906 100644
--- a/include/uapi/linux/ultraeth_nl.h
+++ b/include/uapi/linux/ultraeth_nl.h
@@ -11,6 +11,8 @@
 
 enum {
 	ULTRAETH_A_CONTEXT_ID = 1,
+	ULTRAETH_A_CONTEXT_NETDEV_IFINDEX,
+	ULTRAETH_A_CONTEXT_NETDEV_NAME,
 
 	__ULTRAETH_A_CONTEXT_MAX,
 	ULTRAETH_A_CONTEXT_MAX = (__ULTRAETH_A_CONTEXT_MAX - 1)
-- 
2.48.1

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