1 files changed, 594 insertions, 0 deletions

diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c
new file mode 100644
index 000000000..d091d51b5
--- /dev/null
+++ b/net/netfilter/nf_flow_table_core.c
@@ -0,0 +1,594 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/netfilter.h>
+#include <linux/rhashtable.h>
+#include <linux/netdevice.h>
+#include <net/ip.h>
+#include <net/ip6_route.h>
+#include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_flow_table.h>
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_l4proto.h>
+#include <net/netfilter/nf_conntrack_tuple.h>
+
+static DEFINE_MUTEX(flowtable_lock);
+static LIST_HEAD(flowtables);
+
+static void
+flow_offload_fill_dir(struct flow_offload *flow,
+		      enum flow_offload_tuple_dir dir)
+{
+	struct flow_offload_tuple *ft = &flow->tuplehash[dir].tuple;
+	struct nf_conntrack_tuple *ctt = &flow->ct->tuplehash[dir].tuple;
+
+	ft->dir = dir;
+
+	switch (ctt->src.l3num) {
+	case NFPROTO_IPV4:
+		ft->src_v4 = ctt->src.u3.in;
+		ft->dst_v4 = ctt->dst.u3.in;
+		break;
+	case NFPROTO_IPV6:
+		ft->src_v6 = ctt->src.u3.in6;
+		ft->dst_v6 = ctt->dst.u3.in6;
+		break;
+	}
+
+	ft->l3proto = ctt->src.l3num;
+	ft->l4proto = ctt->dst.protonum;
+	ft->src_port = ctt->src.u.tcp.port;
+	ft->dst_port = ctt->dst.u.tcp.port;
+}
+
+struct flow_offload *flow_offload_alloc(struct nf_conn *ct)
+{
+	struct flow_offload *flow;
+
+	if (unlikely(nf_ct_is_dying(ct) ||
+	    !atomic_inc_not_zero(&ct->ct_general.use)))
+		return NULL;
+
+	flow = kzalloc(sizeof(*flow), GFP_ATOMIC);
+	if (!flow)
+		goto err_ct_refcnt;
+
+	flow->ct = ct;
+
+	flow_offload_fill_dir(flow, FLOW_OFFLOAD_DIR_ORIGINAL);
+	flow_offload_fill_dir(flow, FLOW_OFFLOAD_DIR_REPLY);
+
+	if (ct->status & IPS_SRC_NAT)
+		__set_bit(NF_FLOW_SNAT, &flow->flags);
+	if (ct->status & IPS_DST_NAT)
+		__set_bit(NF_FLOW_DNAT, &flow->flags);
+
+	return flow;
+
+err_ct_refcnt:
+	nf_ct_put(ct);
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(flow_offload_alloc);
+
+static int flow_offload_fill_route(struct flow_offload *flow,
+				   const struct nf_flow_route *route,
+				   enum flow_offload_tuple_dir dir)
+{
+	struct flow_offload_tuple *flow_tuple = &flow->tuplehash[dir].tuple;
+	struct dst_entry *other_dst = route->tuple[!dir].dst;
+	struct dst_entry *dst = route->tuple[dir].dst;
+
+	if (!dst_hold_safe(route->tuple[dir].dst))
+		return -1;
+
+	switch (flow_tuple->l3proto) {
+	case NFPROTO_IPV4:
+		flow_tuple->mtu = ip_dst_mtu_maybe_forward(dst, true);
+		break;
+	case NFPROTO_IPV6:
+		flow_tuple->mtu = ip6_dst_mtu_forward(dst);
+		break;
+	}
+
+	flow_tuple->iifidx = other_dst->dev->ifindex;
+	flow_tuple->dst_cache = dst;
+
+	return 0;
+}
+
+int flow_offload_route_init(struct flow_offload *flow,
+			    const struct nf_flow_route *route)
+{
+	int err;
+
+	err = flow_offload_fill_route(flow, route, FLOW_OFFLOAD_DIR_ORIGINAL);
+	if (err < 0)
+		return err;
+
+	err = flow_offload_fill_route(flow, route, FLOW_OFFLOAD_DIR_REPLY);
+	if (err < 0)
+		goto err_route_reply;
+
+	flow->type = NF_FLOW_OFFLOAD_ROUTE;
+
+	return 0;
+
+err_route_reply:
+	dst_release(route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].dst);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(flow_offload_route_init);
+
+static void flow_offload_fixup_tcp(struct ip_ct_tcp *tcp)
+{
+	tcp->state = TCP_CONNTRACK_ESTABLISHED;
+	tcp->seen[0].td_maxwin = 0;
+	tcp->seen[1].td_maxwin = 0;
+}
+
+#define NF_FLOWTABLE_TCP_PICKUP_TIMEOUT	(120 * HZ)
+#define NF_FLOWTABLE_UDP_PICKUP_TIMEOUT	(30 * HZ)
+
+static void flow_offload_fixup_ct_timeout(struct nf_conn *ct)
+{
+	const struct nf_conntrack_l4proto *l4proto;
+	int l4num = nf_ct_protonum(ct);
+	unsigned int timeout;
+
+	l4proto = nf_ct_l4proto_find(l4num);
+	if (!l4proto)
+		return;
+
+	if (l4num == IPPROTO_TCP)
+		timeout = NF_FLOWTABLE_TCP_PICKUP_TIMEOUT;
+	else if (l4num == IPPROTO_UDP)
+		timeout = NF_FLOWTABLE_UDP_PICKUP_TIMEOUT;
+	else
+		return;
+
+	if (nf_flow_timeout_delta(READ_ONCE(ct->timeout)) > (__s32)timeout)
+		WRITE_ONCE(ct->timeout, nfct_time_stamp + timeout);
+}
+
+static void flow_offload_fixup_ct_state(struct nf_conn *ct)
+{
+	if (nf_ct_protonum(ct) == IPPROTO_TCP)
+		flow_offload_fixup_tcp(&ct->proto.tcp);
+}
+
+static void flow_offload_fixup_ct(struct nf_conn *ct)
+{
+	flow_offload_fixup_ct_state(ct);
+	flow_offload_fixup_ct_timeout(ct);
+}
+
+static void flow_offload_route_release(struct flow_offload *flow)
+{
+	dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_cache);
+	dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_cache);
+}
+
+void flow_offload_free(struct flow_offload *flow)
+{
+	switch (flow->type) {
+	case NF_FLOW_OFFLOAD_ROUTE:
+		flow_offload_route_release(flow);
+		break;
+	default:
+		break;
+	}
+	nf_ct_put(flow->ct);
+	kfree_rcu(flow, rcu_head);
+}
+EXPORT_SYMBOL_GPL(flow_offload_free);
+
+static u32 flow_offload_hash(const void *data, u32 len, u32 seed)
+{
+	const struct flow_offload_tuple *tuple = data;
+
+	return jhash(tuple, offsetof(struct flow_offload_tuple, dir), seed);
+}
+
+static u32 flow_offload_hash_obj(const void *data, u32 len, u32 seed)
+{
+	const struct flow_offload_tuple_rhash *tuplehash = data;
+
+	return jhash(&tuplehash->tuple, offsetof(struct flow_offload_tuple, dir), seed);
+}
+
+static int flow_offload_hash_cmp(struct rhashtable_compare_arg *arg,
+					const void *ptr)
+{
+	const struct flow_offload_tuple *tuple = arg->key;
+	const struct flow_offload_tuple_rhash *x = ptr;
+
+	if (memcmp(&x->tuple, tuple, offsetof(struct flow_offload_tuple, dir)))
+		return 1;
+
+	return 0;
+}
+
+static const struct rhashtable_params nf_flow_offload_rhash_params = {
+	.head_offset		= offsetof(struct flow_offload_tuple_rhash, node),
+	.hashfn			= flow_offload_hash,
+	.obj_hashfn		= flow_offload_hash_obj,
+	.obj_cmpfn		= flow_offload_hash_cmp,
+	.automatic_shrinking	= true,
+};
+
+int flow_offload_add(struct nf_flowtable *flow_table, struct flow_offload *flow)
+{
+	int err;
+
+	flow->timeout = nf_flowtable_time_stamp + NF_FLOW_TIMEOUT;
+
+	err = rhashtable_insert_fast(&flow_table->rhashtable,
+				     &flow->tuplehash[0].node,
+				     nf_flow_offload_rhash_params);
+	if (err < 0)
+		return err;
+
+	err = rhashtable_insert_fast(&flow_table->rhashtable,
+				     &flow->tuplehash[1].node,
+				     nf_flow_offload_rhash_params);
+	if (err < 0) {
+		rhashtable_remove_fast(&flow_table->rhashtable,
+				       &flow->tuplehash[0].node,
+				       nf_flow_offload_rhash_params);
+		return err;
+	}
+
+	nf_ct_offload_timeout(flow->ct);
+
+	if (nf_flowtable_hw_offload(flow_table)) {
+		__set_bit(NF_FLOW_HW, &flow->flags);
+		nf_flow_offload_add(flow_table, flow);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(flow_offload_add);
+
+void flow_offload_refresh(struct nf_flowtable *flow_table,
+			  struct flow_offload *flow)
+{
+	flow->timeout = nf_flowtable_time_stamp + NF_FLOW_TIMEOUT;
+
+	if (likely(!nf_flowtable_hw_offload(flow_table)))
+		return;
+
+	nf_flow_offload_add(flow_table, flow);
+}
+EXPORT_SYMBOL_GPL(flow_offload_refresh);
+
+static inline bool nf_flow_has_expired(const struct flow_offload *flow)
+{
+	return nf_flow_timeout_delta(flow->timeout) <= 0;
+}
+
+static void flow_offload_del(struct nf_flowtable *flow_table,
+			     struct flow_offload *flow)
+{
+	rhashtable_remove_fast(&flow_table->rhashtable,
+			       &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node,
+			       nf_flow_offload_rhash_params);
+	rhashtable_remove_fast(&flow_table->rhashtable,
+			       &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node,
+			       nf_flow_offload_rhash_params);
+
+	clear_bit(IPS_OFFLOAD_BIT, &flow->ct->status);
+
+	if (nf_flow_has_expired(flow))
+		flow_offload_fixup_ct(flow->ct);
+	else
+		flow_offload_fixup_ct_timeout(flow->ct);
+
+	flow_offload_free(flow);
+}
+
+void flow_offload_teardown(struct flow_offload *flow)
+{
+	set_bit(NF_FLOW_TEARDOWN, &flow->flags);
+
+	flow_offload_fixup_ct_state(flow->ct);
+}
+EXPORT_SYMBOL_GPL(flow_offload_teardown);
+
+struct flow_offload_tuple_rhash *
+flow_offload_lookup(struct nf_flowtable *flow_table,
+		    struct flow_offload_tuple *tuple)
+{
+	struct flow_offload_tuple_rhash *tuplehash;
+	struct flow_offload *flow;
+	int dir;
+
+	tuplehash = rhashtable_lookup(&flow_table->rhashtable, tuple,
+				      nf_flow_offload_rhash_params);
+	if (!tuplehash)
+		return NULL;
+
+	dir = tuplehash->tuple.dir;
+	flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
+	if (test_bit(NF_FLOW_TEARDOWN, &flow->flags))
+		return NULL;
+
+	if (unlikely(nf_ct_is_dying(flow->ct)))
+		return NULL;
+
+	return tuplehash;
+}
+EXPORT_SYMBOL_GPL(flow_offload_lookup);
+
+static int
+nf_flow_table_iterate(struct nf_flowtable *flow_table,
+		      void (*iter)(struct flow_offload *flow, void *data),
+		      void *data)
+{
+	struct flow_offload_tuple_rhash *tuplehash;
+	struct rhashtable_iter hti;
+	struct flow_offload *flow;
+	int err = 0;
+
+	rhashtable_walk_enter(&flow_table->rhashtable, &hti);
+	rhashtable_walk_start(&hti);
+
+	while ((tuplehash = rhashtable_walk_next(&hti))) {
+		if (IS_ERR(tuplehash)) {
+			if (PTR_ERR(tuplehash) != -EAGAIN) {
+				err = PTR_ERR(tuplehash);
+				break;
+			}
+			continue;
+		}
+		if (tuplehash->tuple.dir)
+			continue;
+
+		flow = container_of(tuplehash, struct flow_offload, tuplehash[0]);
+
+		iter(flow, data);
+	}
+	rhashtable_walk_stop(&hti);
+	rhashtable_walk_exit(&hti);
+
+	return err;
+}
+
+static void nf_flow_offload_gc_step(struct flow_offload *flow, void *data)
+{
+	struct nf_flowtable *flow_table = data;
+
+	if (nf_flow_has_expired(flow) || nf_ct_is_dying(flow->ct))
+		set_bit(NF_FLOW_TEARDOWN, &flow->flags);
+
+	if (test_bit(NF_FLOW_TEARDOWN, &flow->flags)) {
+		if (test_bit(NF_FLOW_HW, &flow->flags)) {
+			if (!test_bit(NF_FLOW_HW_DYING, &flow->flags))
+				nf_flow_offload_del(flow_table, flow);
+			else if (test_bit(NF_FLOW_HW_DEAD, &flow->flags))
+				flow_offload_del(flow_table, flow);
+		} else {
+			flow_offload_del(flow_table, flow);
+		}
+	} else if (test_bit(NF_FLOW_HW, &flow->flags)) {
+		nf_flow_offload_stats(flow_table, flow);
+	}
+}
+
+static void nf_flow_offload_work_gc(struct work_struct *work)
+{
+	struct nf_flowtable *flow_table;
+
+	flow_table = container_of(work, struct nf_flowtable, gc_work.work);
+	nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, flow_table);
+	queue_delayed_work(system_power_efficient_wq, &flow_table->gc_work, HZ);
+}
+
+
+static int nf_flow_nat_port_tcp(struct sk_buff *skb, unsigned int thoff,
+				__be16 port, __be16 new_port)
+{
+	struct tcphdr *tcph;
+
+	if (skb_try_make_writable(skb, thoff + sizeof(*tcph)))
+		return -1;
+
+	tcph = (void *)(skb_network_header(skb) + thoff);
+	inet_proto_csum_replace2(&tcph->check, skb, port, new_port, false);
+
+	return 0;
+}
+
+static int nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff,
+				__be16 port, __be16 new_port)
+{
+	struct udphdr *udph;
+
+	if (skb_try_make_writable(skb, thoff + sizeof(*udph)))
+		return -1;
+
+	udph = (void *)(skb_network_header(skb) + thoff);
+	if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
+		inet_proto_csum_replace2(&udph->check, skb, port,
+					 new_port, false);
+		if (!udph->check)
+			udph->check = CSUM_MANGLED_0;
+	}
+
+	return 0;
+}
+
+static int nf_flow_nat_port(struct sk_buff *skb, unsigned int thoff,
+			    u8 protocol, __be16 port, __be16 new_port)
+{
+	switch (protocol) {
+	case IPPROTO_TCP:
+		if (nf_flow_nat_port_tcp(skb, thoff, port, new_port) < 0)
+			return NF_DROP;
+		break;
+	case IPPROTO_UDP:
+		if (nf_flow_nat_port_udp(skb, thoff, port, new_port) < 0)
+			return NF_DROP;
+		break;
+	}
+
+	return 0;
+}
+
+int nf_flow_snat_port(const struct flow_offload *flow,
+		      struct sk_buff *skb, unsigned int thoff,
+		      u8 protocol, enum flow_offload_tuple_dir dir)
+{
+	struct flow_ports *hdr;
+	__be16 port, new_port;
+
+	if (skb_try_make_writable(skb, thoff + sizeof(*hdr)))
+		return -1;
+
+	hdr = (void *)(skb_network_header(skb) + thoff);
+
+	switch (dir) {
+	case FLOW_OFFLOAD_DIR_ORIGINAL:
+		port = hdr->source;
+		new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port;
+		hdr->source = new_port;
+		break;
+	case FLOW_OFFLOAD_DIR_REPLY:
+		port = hdr->dest;
+		new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port;
+		hdr->dest = new_port;
+		break;
+	default:
+		return -1;
+	}
+
+	return nf_flow_nat_port(skb, thoff, protocol, port, new_port);
+}
+EXPORT_SYMBOL_GPL(nf_flow_snat_port);
+
+int nf_flow_dnat_port(const struct flow_offload *flow,
+		      struct sk_buff *skb, unsigned int thoff,
+		      u8 protocol, enum flow_offload_tuple_dir dir)
+{
+	struct flow_ports *hdr;
+	__be16 port, new_port;
+
+	if (skb_try_make_writable(skb, thoff + sizeof(*hdr)))
+		return -1;
+
+	hdr = (void *)(skb_network_header(skb) + thoff);
+
+	switch (dir) {
+	case FLOW_OFFLOAD_DIR_ORIGINAL:
+		port = hdr->dest;
+		new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_port;
+		hdr->dest = new_port;
+		break;
+	case FLOW_OFFLOAD_DIR_REPLY:
+		port = hdr->source;
+		new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_port;
+		hdr->source = new_port;
+		break;
+	default:
+		return -1;
+	}
+
+	return nf_flow_nat_port(skb, thoff, protocol, port, new_port);
+}
+EXPORT_SYMBOL_GPL(nf_flow_dnat_port);
+
+int nf_flow_table_init(struct nf_flowtable *flowtable)
+{
+	int err;
+
+	INIT_DELAYED_WORK(&flowtable->gc_work, nf_flow_offload_work_gc);
+	flow_block_init(&flowtable->flow_block);
+	init_rwsem(&flowtable->flow_block_lock);
+
+	err = rhashtable_init(&flowtable->rhashtable,
+			      &nf_flow_offload_rhash_params);
+	if (err < 0)
+		return err;
+
+	queue_delayed_work(system_power_efficient_wq,
+			   &flowtable->gc_work, HZ);
+
+	mutex_lock(&flowtable_lock);
+	list_add(&flowtable->list, &flowtables);
+	mutex_unlock(&flowtable_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nf_flow_table_init);
+
+static void nf_flow_table_do_cleanup(struct flow_offload *flow, void *data)
+{
+	struct net_device *dev = data;
+
+	if (!dev) {
+		flow_offload_teardown(flow);
+		return;
+	}
+
+	if (net_eq(nf_ct_net(flow->ct), dev_net(dev)) &&
+	    (flow->tuplehash[0].tuple.iifidx == dev->ifindex ||
+	     flow->tuplehash[1].tuple.iifidx == dev->ifindex))
+		flow_offload_teardown(flow);
+}
+
+void nf_flow_table_gc_cleanup(struct nf_flowtable *flowtable,
+			      struct net_device *dev)
+{
+	nf_flow_table_iterate(flowtable, nf_flow_table_do_cleanup, dev);
+	flush_delayed_work(&flowtable->gc_work);
+	nf_flow_table_offload_flush(flowtable);
+}
+
+void nf_flow_table_cleanup(struct net_device *dev)
+{
+	struct nf_flowtable *flowtable;
+
+	mutex_lock(&flowtable_lock);
+	list_for_each_entry(flowtable, &flowtables, list)
+		nf_flow_table_gc_cleanup(flowtable, dev);
+	mutex_unlock(&flowtable_lock);
+}
+EXPORT_SYMBOL_GPL(nf_flow_table_cleanup);
+
+void nf_flow_table_free(struct nf_flowtable *flow_table)
+{
+	mutex_lock(&flowtable_lock);
+	list_del(&flow_table->list);
+	mutex_unlock(&flowtable_lock);
+
+	cancel_delayed_work_sync(&flow_table->gc_work);
+	nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL);
+	nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, flow_table);
+	nf_flow_table_offload_flush(flow_table);
+	if (nf_flowtable_hw_offload(flow_table))
+		nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step,
+				      flow_table);
+	rhashtable_destroy(&flow_table->rhashtable);
+}
+EXPORT_SYMBOL_GPL(nf_flow_table_free);
+
+static int __init nf_flow_table_module_init(void)
+{
+	return nf_flow_table_offload_init();
+}
+
+static void __exit nf_flow_table_module_exit(void)
+{
+	nf_flow_table_offload_exit();
+}
+
+module_init(nf_flow_table_module_init);
+module_exit(nf_flow_table_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
+MODULE_DESCRIPTION("Netfilter flow table module");