1 files changed, 532 insertions, 0 deletions

diff --git a/net/netfilter/nft_flow_offload.c b/net/netfilter/nft_flow_offload.c
new file mode 100644
index 000000000..397351fa4
--- /dev/null
+++ b/net/netfilter/nft_flow_offload.c
@@ -0,0 +1,532 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/workqueue.h>
+#include <linux/spinlock.h>
+#include <linux/netfilter/nf_conntrack_common.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/ip.h> /* for ipv4 options. */
+#include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_core.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_extend.h>
+#include <net/netfilter/nf_flow_table.h>
+
+struct nft_flow_offload {
+	struct nft_flowtable	*flowtable;
+};
+
+static enum flow_offload_xmit_type nft_xmit_type(struct dst_entry *dst)
+{
+	if (dst_xfrm(dst))
+		return FLOW_OFFLOAD_XMIT_XFRM;
+
+	return FLOW_OFFLOAD_XMIT_NEIGH;
+}
+
+static void nft_default_forward_path(struct nf_flow_route *route,
+				     struct dst_entry *dst_cache,
+				     enum ip_conntrack_dir dir)
+{
+	route->tuple[!dir].in.ifindex	= dst_cache->dev->ifindex;
+	route->tuple[dir].dst		= dst_cache;
+	route->tuple[dir].xmit_type	= nft_xmit_type(dst_cache);
+}
+
+static bool nft_is_valid_ether_device(const struct net_device *dev)
+{
+	if (!dev || (dev->flags & IFF_LOOPBACK) || dev->type != ARPHRD_ETHER ||
+	    dev->addr_len != ETH_ALEN || !is_valid_ether_addr(dev->dev_addr))
+		return false;
+
+	return true;
+}
+
+static int nft_dev_fill_forward_path(const struct nf_flow_route *route,
+				     const struct dst_entry *dst_cache,
+				     const struct nf_conn *ct,
+				     enum ip_conntrack_dir dir, u8 *ha,
+				     struct net_device_path_stack *stack)
+{
+	const void *daddr = &ct->tuplehash[!dir].tuple.src.u3;
+	struct net_device *dev = dst_cache->dev;
+	struct neighbour *n;
+	u8 nud_state;
+
+	if (!nft_is_valid_ether_device(dev))
+		goto out;
+
+	n = dst_neigh_lookup(dst_cache, daddr);
+	if (!n)
+		return -1;
+
+	read_lock_bh(&n->lock);
+	nud_state = n->nud_state;
+	ether_addr_copy(ha, n->ha);
+	read_unlock_bh(&n->lock);
+	neigh_release(n);
+
+	if (!(nud_state & NUD_VALID))
+		return -1;
+
+out:
+	return dev_fill_forward_path(dev, ha, stack);
+}
+
+struct nft_forward_info {
+	const struct net_device *indev;
+	const struct net_device *outdev;
+	const struct net_device *hw_outdev;
+	struct id {
+		__u16	id;
+		__be16	proto;
+	} encap[NF_FLOW_TABLE_ENCAP_MAX];
+	u8 num_encaps;
+	u8 ingress_vlans;
+	u8 h_source[ETH_ALEN];
+	u8 h_dest[ETH_ALEN];
+	enum flow_offload_xmit_type xmit_type;
+};
+
+static void nft_dev_path_info(const struct net_device_path_stack *stack,
+			      struct nft_forward_info *info,
+			      unsigned char *ha, struct nf_flowtable *flowtable)
+{
+	const struct net_device_path *path;
+	int i;
+
+	memcpy(info->h_dest, ha, ETH_ALEN);
+
+	for (i = 0; i < stack->num_paths; i++) {
+		path = &stack->path[i];
+		switch (path->type) {
+		case DEV_PATH_ETHERNET:
+		case DEV_PATH_DSA:
+		case DEV_PATH_VLAN:
+		case DEV_PATH_PPPOE:
+			info->indev = path->dev;
+			if (is_zero_ether_addr(info->h_source))
+				memcpy(info->h_source, path->dev->dev_addr, ETH_ALEN);
+
+			if (path->type == DEV_PATH_ETHERNET)
+				break;
+			if (path->type == DEV_PATH_DSA) {
+				i = stack->num_paths;
+				break;
+			}
+
+			/* DEV_PATH_VLAN and DEV_PATH_PPPOE */
+			if (info->num_encaps >= NF_FLOW_TABLE_ENCAP_MAX) {
+				info->indev = NULL;
+				break;
+			}
+			if (!info->outdev)
+				info->outdev = path->dev;
+			info->encap[info->num_encaps].id = path->encap.id;
+			info->encap[info->num_encaps].proto = path->encap.proto;
+			info->num_encaps++;
+			if (path->type == DEV_PATH_PPPOE)
+				memcpy(info->h_dest, path->encap.h_dest, ETH_ALEN);
+			break;
+		case DEV_PATH_BRIDGE:
+			if (is_zero_ether_addr(info->h_source))
+				memcpy(info->h_source, path->dev->dev_addr, ETH_ALEN);
+
+			switch (path->bridge.vlan_mode) {
+			case DEV_PATH_BR_VLAN_UNTAG_HW:
+				info->ingress_vlans |= BIT(info->num_encaps - 1);
+				break;
+			case DEV_PATH_BR_VLAN_TAG:
+				info->encap[info->num_encaps].id = path->bridge.vlan_id;
+				info->encap[info->num_encaps].proto = path->bridge.vlan_proto;
+				info->num_encaps++;
+				break;
+			case DEV_PATH_BR_VLAN_UNTAG:
+				info->num_encaps--;
+				break;
+			case DEV_PATH_BR_VLAN_KEEP:
+				break;
+			}
+			info->xmit_type = FLOW_OFFLOAD_XMIT_DIRECT;
+			break;
+		default:
+			info->indev = NULL;
+			break;
+		}
+	}
+	if (!info->outdev)
+		info->outdev = info->indev;
+
+	info->hw_outdev = info->indev;
+
+	if (nf_flowtable_hw_offload(flowtable) &&
+	    nft_is_valid_ether_device(info->indev))
+		info->xmit_type = FLOW_OFFLOAD_XMIT_DIRECT;
+}
+
+static bool nft_flowtable_find_dev(const struct net_device *dev,
+				   struct nft_flowtable *ft)
+{
+	struct nft_hook *hook;
+	bool found = false;
+
+	list_for_each_entry_rcu(hook, &ft->hook_list, list) {
+		if (hook->ops.dev != dev)
+			continue;
+
+		found = true;
+		break;
+	}
+
+	return found;
+}
+
+static void nft_dev_forward_path(struct nf_flow_route *route,
+				 const struct nf_conn *ct,
+				 enum ip_conntrack_dir dir,
+				 struct nft_flowtable *ft)
+{
+	const struct dst_entry *dst = route->tuple[dir].dst;
+	struct net_device_path_stack stack;
+	struct nft_forward_info info = {};
+	unsigned char ha[ETH_ALEN];
+	int i;
+
+	if (nft_dev_fill_forward_path(route, dst, ct, dir, ha, &stack) >= 0)
+		nft_dev_path_info(&stack, &info, ha, &ft->data);
+
+	if (!info.indev || !nft_flowtable_find_dev(info.indev, ft))
+		return;
+
+	route->tuple[!dir].in.ifindex = info.indev->ifindex;
+	for (i = 0; i < info.num_encaps; i++) {
+		route->tuple[!dir].in.encap[i].id = info.encap[i].id;
+		route->tuple[!dir].in.encap[i].proto = info.encap[i].proto;
+	}
+	route->tuple[!dir].in.num_encaps = info.num_encaps;
+	route->tuple[!dir].in.ingress_vlans = info.ingress_vlans;
+
+	if (info.xmit_type == FLOW_OFFLOAD_XMIT_DIRECT) {
+		memcpy(route->tuple[dir].out.h_source, info.h_source, ETH_ALEN);
+		memcpy(route->tuple[dir].out.h_dest, info.h_dest, ETH_ALEN);
+		route->tuple[dir].out.ifindex = info.outdev->ifindex;
+		route->tuple[dir].out.hw_ifindex = info.hw_outdev->ifindex;
+		route->tuple[dir].xmit_type = info.xmit_type;
+	}
+}
+
+static int nft_flow_route(const struct nft_pktinfo *pkt,
+			  const struct nf_conn *ct,
+			  struct nf_flow_route *route,
+			  enum ip_conntrack_dir dir,
+			  struct nft_flowtable *ft)
+{
+	struct dst_entry *this_dst = skb_dst(pkt->skb);
+	struct dst_entry *other_dst = NULL;
+	struct flowi fl;
+
+	memset(&fl, 0, sizeof(fl));
+	switch (nft_pf(pkt)) {
+	case NFPROTO_IPV4:
+		fl.u.ip4.daddr = ct->tuplehash[dir].tuple.src.u3.ip;
+		fl.u.ip4.saddr = ct->tuplehash[!dir].tuple.src.u3.ip;
+		fl.u.ip4.flowi4_oif = nft_in(pkt)->ifindex;
+		fl.u.ip4.flowi4_iif = this_dst->dev->ifindex;
+		fl.u.ip4.flowi4_tos = RT_TOS(ip_hdr(pkt->skb)->tos);
+		fl.u.ip4.flowi4_mark = pkt->skb->mark;
+		fl.u.ip4.flowi4_flags = FLOWI_FLAG_ANYSRC;
+		break;
+	case NFPROTO_IPV6:
+		fl.u.ip6.daddr = ct->tuplehash[dir].tuple.src.u3.in6;
+		fl.u.ip6.saddr = ct->tuplehash[!dir].tuple.src.u3.in6;
+		fl.u.ip6.flowi6_oif = nft_in(pkt)->ifindex;
+		fl.u.ip6.flowi6_iif = this_dst->dev->ifindex;
+		fl.u.ip6.flowlabel = ip6_flowinfo(ipv6_hdr(pkt->skb));
+		fl.u.ip6.flowi6_mark = pkt->skb->mark;
+		fl.u.ip6.flowi6_flags = FLOWI_FLAG_ANYSRC;
+		break;
+	}
+
+	if (!dst_hold_safe(this_dst))
+		return -ENOENT;
+
+	nf_route(nft_net(pkt), &other_dst, &fl, false, nft_pf(pkt));
+	if (!other_dst) {
+		dst_release(this_dst);
+		return -ENOENT;
+	}
+
+	nft_default_forward_path(route, this_dst, dir);
+	nft_default_forward_path(route, other_dst, !dir);
+
+	if (route->tuple[dir].xmit_type	== FLOW_OFFLOAD_XMIT_NEIGH &&
+	    route->tuple[!dir].xmit_type == FLOW_OFFLOAD_XMIT_NEIGH) {
+		nft_dev_forward_path(route, ct, dir, ft);
+		nft_dev_forward_path(route, ct, !dir, ft);
+	}
+
+	return 0;
+}
+
+static bool nft_flow_offload_skip(struct sk_buff *skb, int family)
+{
+	if (skb_sec_path(skb))
+		return true;
+
+	if (family == NFPROTO_IPV4) {
+		const struct ip_options *opt;
+
+		opt = &(IPCB(skb)->opt);
+
+		if (unlikely(opt->optlen))
+			return true;
+	}
+
+	return false;
+}
+
+static void nft_flow_offload_eval(const struct nft_expr *expr,
+				  struct nft_regs *regs,
+				  const struct nft_pktinfo *pkt)
+{
+	struct nft_flow_offload *priv = nft_expr_priv(expr);
+	struct nf_flowtable *flowtable = &priv->flowtable->data;
+	struct tcphdr _tcph, *tcph = NULL;
+	struct nf_flow_route route = {};
+	enum ip_conntrack_info ctinfo;
+	struct flow_offload *flow;
+	enum ip_conntrack_dir dir;
+	struct nf_conn *ct;
+	int ret;
+
+	if (nft_flow_offload_skip(pkt->skb, nft_pf(pkt)))
+		goto out;
+
+	ct = nf_ct_get(pkt->skb, &ctinfo);
+	if (!ct)
+		goto out;
+
+	switch (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum) {
+	case IPPROTO_TCP:
+		tcph = skb_header_pointer(pkt->skb, nft_thoff(pkt),
+					  sizeof(_tcph), &_tcph);
+		if (unlikely(!tcph || tcph->fin || tcph->rst ||
+			     !nf_conntrack_tcp_established(ct)))
+			goto out;
+		break;
+	case IPPROTO_UDP:
+		break;
+#ifdef CONFIG_NF_CT_PROTO_GRE
+	case IPPROTO_GRE: {
+		struct nf_conntrack_tuple *tuple;
+
+		if (ct->status & IPS_NAT_MASK)
+			goto out;
+		tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
+		/* No support for GRE v1 */
+		if (tuple->src.u.gre.key || tuple->dst.u.gre.key)
+			goto out;
+		break;
+	}
+#endif
+	default:
+		goto out;
+	}
+
+	if (nf_ct_ext_exist(ct, NF_CT_EXT_HELPER) ||
+	    ct->status & (IPS_SEQ_ADJUST | IPS_NAT_CLASH))
+		goto out;
+
+	if (!nf_ct_is_confirmed(ct))
+		goto out;
+
+	if (test_and_set_bit(IPS_OFFLOAD_BIT, &ct->status))
+		goto out;
+
+	dir = CTINFO2DIR(ctinfo);
+	if (nft_flow_route(pkt, ct, &route, dir, priv->flowtable) < 0)
+		goto err_flow_route;
+
+	flow = flow_offload_alloc(ct);
+	if (!flow)
+		goto err_flow_alloc;
+
+	flow_offload_route_init(flow, &route);
+
+	if (tcph) {
+		ct->proto.tcp.seen[0].flags |= IP_CT_TCP_FLAG_BE_LIBERAL;
+		ct->proto.tcp.seen[1].flags |= IP_CT_TCP_FLAG_BE_LIBERAL;
+	}
+
+	ret = flow_offload_add(flowtable, flow);
+	if (ret < 0)
+		goto err_flow_add;
+
+	return;
+
+err_flow_add:
+	flow_offload_free(flow);
+err_flow_alloc:
+	dst_release(route.tuple[dir].dst);
+	dst_release(route.tuple[!dir].dst);
+err_flow_route:
+	clear_bit(IPS_OFFLOAD_BIT, &ct->status);
+out:
+	regs->verdict.code = NFT_BREAK;
+}
+
+static int nft_flow_offload_validate(const struct nft_ctx *ctx,
+				     const struct nft_expr *expr,
+				     const struct nft_data **data)
+{
+	unsigned int hook_mask = (1 << NF_INET_FORWARD);
+
+	if (ctx->family != NFPROTO_IPV4 &&
+	    ctx->family != NFPROTO_IPV6 &&
+	    ctx->family != NFPROTO_INET)
+		return -EOPNOTSUPP;
+
+	return nft_chain_validate_hooks(ctx->chain, hook_mask);
+}
+
+static const struct nla_policy nft_flow_offload_policy[NFTA_FLOW_MAX + 1] = {
+	[NFTA_FLOW_TABLE_NAME]	= { .type = NLA_STRING,
+				    .len = NFT_NAME_MAXLEN - 1 },
+};
+
+static int nft_flow_offload_init(const struct nft_ctx *ctx,
+				 const struct nft_expr *expr,
+				 const struct nlattr * const tb[])
+{
+	struct nft_flow_offload *priv = nft_expr_priv(expr);
+	u8 genmask = nft_genmask_next(ctx->net);
+	struct nft_flowtable *flowtable;
+
+	if (!tb[NFTA_FLOW_TABLE_NAME])
+		return -EINVAL;
+
+	flowtable = nft_flowtable_lookup(ctx->table, tb[NFTA_FLOW_TABLE_NAME],
+					 genmask);
+	if (IS_ERR(flowtable))
+		return PTR_ERR(flowtable);
+
+	if (!nft_use_inc(&flowtable->use))
+		return -EMFILE;
+
+	priv->flowtable = flowtable;
+
+	return nf_ct_netns_get(ctx->net, ctx->family);
+}
+
+static void nft_flow_offload_deactivate(const struct nft_ctx *ctx,
+					const struct nft_expr *expr,
+					enum nft_trans_phase phase)
+{
+	struct nft_flow_offload *priv = nft_expr_priv(expr);
+
+	nf_tables_deactivate_flowtable(ctx, priv->flowtable, phase);
+}
+
+static void nft_flow_offload_activate(const struct nft_ctx *ctx,
+				      const struct nft_expr *expr)
+{
+	struct nft_flow_offload *priv = nft_expr_priv(expr);
+
+	nft_use_inc_restore(&priv->flowtable->use);
+}
+
+static void nft_flow_offload_destroy(const struct nft_ctx *ctx,
+				     const struct nft_expr *expr)
+{
+	nf_ct_netns_put(ctx->net, ctx->family);
+}
+
+static int nft_flow_offload_dump(struct sk_buff *skb,
+				 const struct nft_expr *expr, bool reset)
+{
+	struct nft_flow_offload *priv = nft_expr_priv(expr);
+
+	if (nla_put_string(skb, NFTA_FLOW_TABLE_NAME, priv->flowtable->name))
+		goto nla_put_failure;
+
+	return 0;
+
+nla_put_failure:
+	return -1;
+}
+
+static struct nft_expr_type nft_flow_offload_type;
+static const struct nft_expr_ops nft_flow_offload_ops = {
+	.type		= &nft_flow_offload_type,
+	.size		= NFT_EXPR_SIZE(sizeof(struct nft_flow_offload)),
+	.eval		= nft_flow_offload_eval,
+	.init		= nft_flow_offload_init,
+	.activate	= nft_flow_offload_activate,
+	.deactivate	= nft_flow_offload_deactivate,
+	.destroy	= nft_flow_offload_destroy,
+	.validate	= nft_flow_offload_validate,
+	.dump		= nft_flow_offload_dump,
+	.reduce		= NFT_REDUCE_READONLY,
+};
+
+static struct nft_expr_type nft_flow_offload_type __read_mostly = {
+	.name		= "flow_offload",
+	.ops		= &nft_flow_offload_ops,
+	.policy		= nft_flow_offload_policy,
+	.maxattr	= NFTA_FLOW_MAX,
+	.owner		= THIS_MODULE,
+};
+
+static int flow_offload_netdev_event(struct notifier_block *this,
+				     unsigned long event, void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+	if (event != NETDEV_DOWN)
+		return NOTIFY_DONE;
+
+	nf_flow_table_cleanup(dev);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block flow_offload_netdev_notifier = {
+	.notifier_call	= flow_offload_netdev_event,
+};
+
+static int __init nft_flow_offload_module_init(void)
+{
+	int err;
+
+	err = register_netdevice_notifier(&flow_offload_netdev_notifier);
+	if (err)
+		goto err;
+
+	err = nft_register_expr(&nft_flow_offload_type);
+	if (err < 0)
+		goto register_expr;
+
+	return 0;
+
+register_expr:
+	unregister_netdevice_notifier(&flow_offload_netdev_notifier);
+err:
+	return err;
+}
+
+static void __exit nft_flow_offload_module_exit(void)
+{
+	nft_unregister_expr(&nft_flow_offload_type);
+	unregister_netdevice_notifier(&flow_offload_netdev_notifier);
+}
+
+module_init(nft_flow_offload_module_init);
+module_exit(nft_flow_offload_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
+MODULE_ALIAS_NFT_EXPR("flow_offload");
+MODULE_DESCRIPTION("nftables hardware flow offload module");