[mirror_ubuntu-jammy-kernel.git] / net / netfilter / nf_flow_table_core.c

#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_tuple.h>

struct flow_offload_entry {
	struct flow_offload	flow;
	struct nf_conn		*ct;
	struct rcu_head		rcu_head;
};

static DEFINE_MUTEX(flowtable_lock);
static LIST_HEAD(flowtables);

static void
flow_offload_fill_dir(struct flow_offload *flow, struct nf_conn *ct,
		      struct nf_flow_route *route,
		      enum flow_offload_tuple_dir dir)
{
	struct flow_offload_tuple *ft = &flow->tuplehash[dir].tuple;
	struct nf_conntrack_tuple *ctt = &ct->tuplehash[dir].tuple;
	struct dst_entry *other_dst = route->tuple[!dir].dst;
	struct dst_entry *dst = route->tuple[dir].dst;

	ft->dir = dir;

	switch (ctt->src.l3num) {
	case NFPROTO_IPV4:
		ft->src_v4 = ctt->src.u3.in;
		ft->dst_v4 = ctt->dst.u3.in;
		ft->mtu = ip_dst_mtu_maybe_forward(dst, true);
		break;
	case NFPROTO_IPV6:
		ft->src_v6 = ctt->src.u3.in6;
		ft->dst_v6 = ctt->dst.u3.in6;
		ft->mtu = ip6_dst_mtu_forward(dst);
		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;

	ft->iifidx = other_dst->dev->ifindex;
	ft->oifidx = dst->dev->ifindex;
	ft->dst_cache = dst;
}

struct flow_offload *
flow_offload_alloc(struct nf_conn *ct, struct nf_flow_route *route)
{
	struct flow_offload_entry *entry;
	struct flow_offload *flow;

	if (unlikely(nf_ct_is_dying(ct) ||
	    !atomic_inc_not_zero(&ct->ct_general.use)))
		return NULL;

	entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
	if (!entry)
		goto err_ct_refcnt;

	flow = &entry->flow;

	if (!dst_hold_safe(route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].dst))
		goto err_dst_cache_original;

	if (!dst_hold_safe(route->tuple[FLOW_OFFLOAD_DIR_REPLY].dst))
		goto err_dst_cache_reply;

	entry->ct = ct;

	flow_offload_fill_dir(flow, ct, route, FLOW_OFFLOAD_DIR_ORIGINAL);
	flow_offload_fill_dir(flow, ct, route, FLOW_OFFLOAD_DIR_REPLY);

	if (ct->status & IPS_SRC_NAT)
		flow->flags |= FLOW_OFFLOAD_SNAT;
	if (ct->status & IPS_DST_NAT)
		flow->flags |= FLOW_OFFLOAD_DNAT;

	return flow;

err_dst_cache_reply:
	dst_release(route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].dst);
err_dst_cache_original:
	kfree(entry);
err_ct_refcnt:
	nf_ct_put(ct);

	return NULL;
}
EXPORT_SYMBOL_GPL(flow_offload_alloc);

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_state(struct nf_conn *ct)
{
	const struct nf_conntrack_l4proto *l4proto;
	unsigned int timeout;
	int l4num;

	l4num = nf_ct_protonum(ct);
	if (l4num == IPPROTO_TCP)
		flow_offload_fixup_tcp(&ct->proto.tcp);

	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;

	ct->timeout = nfct_time_stamp + timeout;
}

void flow_offload_free(struct flow_offload *flow)
{
	struct flow_offload_entry *e;

	dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_cache);
	dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_cache);
	e = container_of(flow, struct flow_offload_entry, flow);
	if (flow->flags & FLOW_OFFLOAD_DYING)
		nf_ct_delete(e->ct, 0, 0);
	nf_ct_put(e->ct);
	kfree_rcu(e, 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;

	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;
	}

	flow->timeout = (u32)jiffies;
	return 0;
}
EXPORT_SYMBOL_GPL(flow_offload_add);

static void flow_offload_del(struct nf_flowtable *flow_table,
			     struct flow_offload *flow)
{
	struct flow_offload_entry *e;

	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);

	e = container_of(flow, struct flow_offload_entry, flow);
	clear_bit(IPS_OFFLOAD_BIT, &e->ct->status);

	flow_offload_free(flow);
}

void flow_offload_teardown(struct flow_offload *flow)
{
	struct flow_offload_entry *e;

	flow->flags |= FLOW_OFFLOAD_TEARDOWN;

	e = container_of(flow, struct flow_offload_entry, flow);
	flow_offload_fixup_ct_state(e->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;
	struct flow_offload_entry *e;
	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 (flow->flags & (FLOW_OFFLOAD_DYING | FLOW_OFFLOAD_TEARDOWN))
		return NULL;

	e = container_of(flow, struct flow_offload_entry, flow);
	if (unlikely(nf_ct_is_dying(e->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 inline bool nf_flow_has_expired(const struct flow_offload *flow)
{
	return (__s32)(flow->timeout - (u32)jiffies) <= 0;
}

static void nf_flow_offload_gc_step(struct flow_offload *flow, void *data)
{
	struct nf_flowtable *flow_table = data;
	struct flow_offload_entry *e;

	e = container_of(flow, struct flow_offload_entry, flow);
	if (nf_flow_has_expired(flow) || nf_ct_is_dying(e->ct) ||
	    (flow->flags & (FLOW_OFFLOAD_DYING | FLOW_OFFLOAD_TEARDOWN)))
		flow_offload_del(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 (!pskb_may_pull(skb, thoff + sizeof(*tcph)) ||
	    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, true);

	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 (!pskb_may_pull(skb, thoff + sizeof(*udph)) ||
	    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, true);
		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 (!pskb_may_pull(skb, thoff + sizeof(*hdr)) ||
	    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 (!pskb_may_pull(skb, thoff + sizeof(*hdr)) ||
	    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_DEFERRABLE_WORK(&flowtable->gc_work, nf_flow_offload_work_gc);

	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;
	struct flow_offload_entry *e;

	e = container_of(flow, struct flow_offload_entry, flow);

	if (!dev) {
		flow_offload_teardown(flow);
		return;
	}
	if (net_eq(nf_ct_net(e->ct), dev_net(dev)) &&
	    (flow->tuplehash[0].tuple.iifidx == dev->ifindex ||
	     flow->tuplehash[1].tuple.iifidx == dev->ifindex))
		flow_offload_dead(flow);
}

static void nf_flow_table_iterate_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);
}

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_iterate_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);
	rhashtable_destroy(&flow_table->rhashtable);
}
EXPORT_SYMBOL_GPL(nf_flow_table_free);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
Commit	Line	Data
ac2a6666 PNA	1	#include <linux/kernel.h>
	2	#include <linux/init.h>
	3	#include <linux/module.h>
	4	#include <linux/netfilter.h>
	5	#include <linux/rhashtable.h>
	6	#include <linux/netdevice.h>
4f3780c0 FF	7	#include <net/ip.h>
4f3780c0 FF	8	#include <net/ip6_route.h>
c0ea1bcb	9	#include <net/netfilter/nf_tables.h>
ac2a6666 PNA	10	#include <net/netfilter/nf_flow_table.h>
	11	#include <net/netfilter/nf_conntrack.h>
	12	#include <net/netfilter/nf_conntrack_core.h>
	13	#include <net/netfilter/nf_conntrack_tuple.h>
	14
	15	struct flow_offload_entry {
	16	struct flow_offload flow;
	17	struct nf_conn *ct;
	18	struct rcu_head rcu_head;
	19	};
	20
84453a90 FF	21	static DEFINE_MUTEX(flowtable_lock);
	22	static LIST_HEAD(flowtables);
	23
047b300e FF	24	static void
	25	flow_offload_fill_dir(struct flow_offload flow, struct nf_conn ct,
	26	struct nf_flow_route *route,
	27	enum flow_offload_tuple_dir dir)
	28	{
	29	struct flow_offload_tuple *ft = &flow->tuplehash[dir].tuple;
	30	struct nf_conntrack_tuple *ctt = &ct->tuplehash[dir].tuple;
10f4e765	31	struct dst_entry *other_dst = route->tuple[!dir].dst;
4f3780c0	32	struct dst_entry *dst = route->tuple[dir].dst;
047b300e FF	33
	34	ft->dir = dir;
	35
	36	switch (ctt->src.l3num) {
	37	case NFPROTO_IPV4:
	38	ft->src_v4 = ctt->src.u3.in;
	39	ft->dst_v4 = ctt->dst.u3.in;
4f3780c0	40	ft->mtu = ip_dst_mtu_maybe_forward(dst, true);
047b300e FF	41	break;
	42	case NFPROTO_IPV6:
	43	ft->src_v6 = ctt->src.u3.in6;
	44	ft->dst_v6 = ctt->dst.u3.in6;
4f3780c0	45	ft->mtu = ip6_dst_mtu_forward(dst);
047b300e FF	46	break;
	47	}
	48
	49	ft->l3proto = ctt->src.l3num;
	50	ft->l4proto = ctt->dst.protonum;
	51	ft->src_port = ctt->src.u.tcp.port;
	52	ft->dst_port = ctt->dst.u.tcp.port;
	53
10f4e765	54	ft->iifidx = other_dst->dev->ifindex;
10f4e765	55	ft->oifidx = dst->dev->ifindex;
4f3780c0	56	ft->dst_cache = dst;
047b300e FF	57	}
047b300e FF	58
ac2a6666 PNA	59	struct flow_offload *
	60	flow_offload_alloc(struct nf_conn ct, struct nf_flow_route route)
	61	{
	62	struct flow_offload_entry *entry;
	63	struct flow_offload *flow;
	64
	65	if (unlikely(nf_ct_is_dying(ct) \|\|
	66	!atomic_inc_not_zero(&ct->ct_general.use)))
	67	return NULL;
	68
	69	entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
	70	if (!entry)
	71	goto err_ct_refcnt;
	72
	73	flow = &entry->flow;
	74
	75	if (!dst_hold_safe(route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].dst))
	76	goto err_dst_cache_original;
	77
	78	if (!dst_hold_safe(route->tuple[FLOW_OFFLOAD_DIR_REPLY].dst))
	79	goto err_dst_cache_reply;
	80
	81	entry->ct = ct;
	82
047b300e FF	83	flow_offload_fill_dir(flow, ct, route, FLOW_OFFLOAD_DIR_ORIGINAL);
047b300e FF	84	flow_offload_fill_dir(flow, ct, route, FLOW_OFFLOAD_DIR_REPLY);
ac2a6666 PNA	85
	86	if (ct->status & IPS_SRC_NAT)
	87	flow->flags \|= FLOW_OFFLOAD_SNAT;
df1e2025	88	if (ct->status & IPS_DST_NAT)
ac2a6666 PNA	89	flow->flags \|= FLOW_OFFLOAD_DNAT;
	90
	91	return flow;
	92
	93	err_dst_cache_reply:
	94	dst_release(route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].dst);
	95	err_dst_cache_original:
	96	kfree(entry);
	97	err_ct_refcnt:
	98	nf_ct_put(ct);
	99
	100	return NULL;
	101	}
	102	EXPORT_SYMBOL_GPL(flow_offload_alloc);
	103
da5984e5 FF	104	static void flow_offload_fixup_tcp(struct ip_ct_tcp *tcp)
	105	{
	106	tcp->state = TCP_CONNTRACK_ESTABLISHED;
	107	tcp->seen[0].td_maxwin = 0;
	108	tcp->seen[1].td_maxwin = 0;
	109	}
	110
e97d9404 FW	111	#define NF_FLOWTABLE_TCP_PICKUP_TIMEOUT (120 * HZ)
	112	#define NF_FLOWTABLE_UDP_PICKUP_TIMEOUT (30 * HZ)
	113
da5984e5 FF	114	static void flow_offload_fixup_ct_state(struct nf_conn *ct)
	115	{
	116	const struct nf_conntrack_l4proto *l4proto;
da5984e5 FF	117	unsigned int timeout;
	118	int l4num;
	119
	120	l4num = nf_ct_protonum(ct);
	121	if (l4num == IPPROTO_TCP)
	122	flow_offload_fixup_tcp(&ct->proto.tcp);
	123
4a60dc74	124	l4proto = nf_ct_l4proto_find(l4num);
da5984e5 FF	125	if (!l4proto)
	126	return;
	127
da5984e5	128	if (l4num == IPPROTO_TCP)
e97d9404	129	timeout = NF_FLOWTABLE_TCP_PICKUP_TIMEOUT;
da5984e5	130	else if (l4num == IPPROTO_UDP)
e97d9404	131	timeout = NF_FLOWTABLE_UDP_PICKUP_TIMEOUT;
da5984e5 FF	132	else
	133	return;
	134
	135	ct->timeout = nfct_time_stamp + timeout;
	136	}
	137
ac2a6666 PNA	138	void flow_offload_free(struct flow_offload *flow)
	139	{
	140	struct flow_offload_entry *e;
	141
	142	dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_cache);
	143	dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_cache);
	144	e = container_of(flow, struct flow_offload_entry, flow);
da5984e5 FF	145	if (flow->flags & FLOW_OFFLOAD_DYING)
da5984e5 FF	146	nf_ct_delete(e->ct, 0, 0);
0ff90b6c FF	147	nf_ct_put(e->ct);
0ff90b6c FF	148	kfree_rcu(e, rcu_head);
ac2a6666 PNA	149	}
	150	EXPORT_SYMBOL_GPL(flow_offload_free);
	151
a268de77 FF	152	static u32 flow_offload_hash(const void *data, u32 len, u32 seed)
	153	{
	154	const struct flow_offload_tuple *tuple = data;
	155
	156	return jhash(tuple, offsetof(struct flow_offload_tuple, dir), seed);
	157	}
	158
	159	static u32 flow_offload_hash_obj(const void *data, u32 len, u32 seed)
	160	{
	161	const struct flow_offload_tuple_rhash *tuplehash = data;
	162
	163	return jhash(&tuplehash->tuple, offsetof(struct flow_offload_tuple, dir), seed);
	164	}
	165
	166	static int flow_offload_hash_cmp(struct rhashtable_compare_arg *arg,
	167	const void *ptr)
	168	{
	169	const struct flow_offload_tuple *tuple = arg->key;
	170	const struct flow_offload_tuple_rhash *x = ptr;
	171
	172	if (memcmp(&x->tuple, tuple, offsetof(struct flow_offload_tuple, dir)))
	173	return 1;
	174
	175	return 0;
	176	}
	177
	178	static const struct rhashtable_params nf_flow_offload_rhash_params = {
	179	.head_offset = offsetof(struct flow_offload_tuple_rhash, node),
	180	.hashfn = flow_offload_hash,
	181	.obj_hashfn = flow_offload_hash_obj,
	182	.obj_cmpfn = flow_offload_hash_cmp,
	183	.automatic_shrinking = true,
	184	};
	185
ac2a6666 PNA	186	int flow_offload_add(struct nf_flowtable flow_table, struct flow_offload flow)
ac2a6666 PNA	187	{
43c8f131 TY	188	int err;
	189
	190	err = rhashtable_insert_fast(&flow_table->rhashtable,
	191	&flow->tuplehash[0].node,
	192	nf_flow_offload_rhash_params);
	193	if (err < 0)
	194	return err;
	195
	196	err = rhashtable_insert_fast(&flow_table->rhashtable,
	197	&flow->tuplehash[1].node,
	198	nf_flow_offload_rhash_params);
	199	if (err < 0) {
	200	rhashtable_remove_fast(&flow_table->rhashtable,
	201	&flow->tuplehash[0].node,
	202	nf_flow_offload_rhash_params);
	203	return err;
	204	}
ac2a6666	205
43c8f131	206	flow->timeout = (u32)jiffies;
ac2a6666 PNA	207	return 0;
	208	}
	209	EXPORT_SYMBOL_GPL(flow_offload_add);
	210
0ff90b6c FF	211	static void flow_offload_del(struct nf_flowtable *flow_table,
0ff90b6c FF	212	struct flow_offload *flow)
ac2a6666	213	{
da5984e5 FF	214	struct flow_offload_entry *e;
da5984e5 FF	215
ac2a6666 PNA	216	rhashtable_remove_fast(&flow_table->rhashtable,
ac2a6666 PNA	217	&flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node,
a268de77	218	nf_flow_offload_rhash_params);
ac2a6666 PNA	219	rhashtable_remove_fast(&flow_table->rhashtable,
ac2a6666 PNA	220	&flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node,
a268de77	221	nf_flow_offload_rhash_params);
ac2a6666	222
da5984e5 FF	223	e = container_of(flow, struct flow_offload_entry, flow);
	224	clear_bit(IPS_OFFLOAD_BIT, &e->ct->status);
	225
0ff90b6c	226	flow_offload_free(flow);
ac2a6666	227	}
ac2a6666	228
59c466dd FF	229	void flow_offload_teardown(struct flow_offload *flow)
59c466dd FF	230	{
da5984e5 FF	231	struct flow_offload_entry *e;
da5984e5 FF	232
59c466dd	233	flow->flags \|= FLOW_OFFLOAD_TEARDOWN;
da5984e5 FF	234
	235	e = container_of(flow, struct flow_offload_entry, flow);
	236	flow_offload_fixup_ct_state(e->ct);
59c466dd FF	237	}
	238	EXPORT_SYMBOL_GPL(flow_offload_teardown);
	239
ac2a6666 PNA	240	struct flow_offload_tuple_rhash *
	241	flow_offload_lookup(struct nf_flowtable *flow_table,
	242	struct flow_offload_tuple *tuple)
	243	{
ba03137f FF	244	struct flow_offload_tuple_rhash *tuplehash;
ba03137f FF	245	struct flow_offload *flow;
8cd2bc98	246	struct flow_offload_entry *e;
ba03137f FF	247	int dir;
ba03137f FF	248
a2d88182 TY	249	tuplehash = rhashtable_lookup(&flow_table->rhashtable, tuple,
a2d88182 TY	250	nf_flow_offload_rhash_params);
ba03137f FF	251	if (!tuplehash)
	252	return NULL;
	253
	254	dir = tuplehash->tuple.dir;
	255	flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
	256	if (flow->flags & (FLOW_OFFLOAD_DYING \| FLOW_OFFLOAD_TEARDOWN))
	257	return NULL;
	258
8cd2bc98 TY	259	e = container_of(flow, struct flow_offload_entry, flow);
	260	if (unlikely(nf_ct_is_dying(e->ct)))
	261	return NULL;
	262
ba03137f	263	return tuplehash;
ac2a6666 PNA	264	}
	265	EXPORT_SYMBOL_GPL(flow_offload_lookup);
	266
49de9c09 TY	267	static int
	268	nf_flow_table_iterate(struct nf_flowtable *flow_table,
	269	void (iter)(struct flow_offload flow, void *data),
	270	void *data)
ac2a6666 PNA	271	{
	272	struct flow_offload_tuple_rhash *tuplehash;
	273	struct rhashtable_iter hti;
	274	struct flow_offload *flow;
0de22baa	275	int err = 0;
ac2a6666	276
0de22baa	277	rhashtable_walk_enter(&flow_table->rhashtable, &hti);
ac2a6666 PNA	278	rhashtable_walk_start(&hti);
	279
	280	while ((tuplehash = rhashtable_walk_next(&hti))) {
	281	if (IS_ERR(tuplehash)) {
0de22baa TY	282	if (PTR_ERR(tuplehash) != -EAGAIN) {
	283	err = PTR_ERR(tuplehash);
	284	break;
	285	}
ac2a6666 PNA	286	continue;
	287	}
	288	if (tuplehash->tuple.dir)
	289	continue;
	290
	291	flow = container_of(tuplehash, struct flow_offload, tuplehash[0]);
	292
	293	iter(flow, data);
	294	}
ac2a6666 PNA	295	rhashtable_walk_stop(&hti);
	296	rhashtable_walk_exit(&hti);
	297
	298	return err;
	299	}
ac2a6666 PNA	300
	301	static inline bool nf_flow_has_expired(const struct flow_offload *flow)
	302	{
	303	return (__s32)(flow->timeout - (u32)jiffies) <= 0;
	304	}
	305
b9660987	306	static void nf_flow_offload_gc_step(struct flow_offload flow, void data)
ac2a6666	307	{
b9660987	308	struct nf_flowtable *flow_table = data;
8cd2bc98	309	struct flow_offload_entry *e;
ac2a6666	310
8cd2bc98 TY	311	e = container_of(flow, struct flow_offload_entry, flow);
8cd2bc98 TY	312	if (nf_flow_has_expired(flow) \|\| nf_ct_is_dying(e->ct) \|\|
b9660987 TY	313	(flow->flags & (FLOW_OFFLOAD_DYING \| FLOW_OFFLOAD_TEARDOWN)))
b9660987 TY	314	flow_offload_del(flow_table, flow);
b408c5b0 PNA	315	}
b408c5b0 PNA	316
a268de77	317	static void nf_flow_offload_work_gc(struct work_struct *work)
b408c5b0 PNA	318	{
	319	struct nf_flowtable *flow_table;
	320
	321	flow_table = container_of(work, struct nf_flowtable, gc_work.work);
b9660987	322	nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, flow_table);
ac2a6666 PNA	323	queue_delayed_work(system_power_efficient_wq, &flow_table->gc_work, HZ);
ac2a6666 PNA	324	}
ac2a6666 PNA	325
	326	static int nf_flow_nat_port_tcp(struct sk_buff *skb, unsigned int thoff,
	327	__be16 port, __be16 new_port)
	328	{
	329	struct tcphdr *tcph;
	330
	331	if (!pskb_may_pull(skb, thoff + sizeof(*tcph)) \|\|
	332	skb_try_make_writable(skb, thoff + sizeof(*tcph)))
	333	return -1;
	334
	335	tcph = (void *)(skb_network_header(skb) + thoff);
	336	inet_proto_csum_replace2(&tcph->check, skb, port, new_port, true);
	337
	338	return 0;
	339	}
	340
	341	static int nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff,
	342	__be16 port, __be16 new_port)
	343	{
	344	struct udphdr *udph;
	345
	346	if (!pskb_may_pull(skb, thoff + sizeof(*udph)) \|\|
	347	skb_try_make_writable(skb, thoff + sizeof(*udph)))
	348	return -1;
	349
	350	udph = (void *)(skb_network_header(skb) + thoff);
	351	if (udph->check \|\| skb->ip_summed == CHECKSUM_PARTIAL) {
	352	inet_proto_csum_replace2(&udph->check, skb, port,
	353	new_port, true);
	354	if (!udph->check)
	355	udph->check = CSUM_MANGLED_0;
	356	}
	357
	358	return 0;
	359	}
	360
	361	static int nf_flow_nat_port(struct sk_buff *skb, unsigned int thoff,
	362	u8 protocol, __be16 port, __be16 new_port)
	363	{
	364	switch (protocol) {
	365	case IPPROTO_TCP:
	366	if (nf_flow_nat_port_tcp(skb, thoff, port, new_port) < 0)
	367	return NF_DROP;
	368	break;
	369	case IPPROTO_UDP:
	370	if (nf_flow_nat_port_udp(skb, thoff, port, new_port) < 0)
	371	return NF_DROP;
	372	break;
	373	}
	374
	375	return 0;
	376	}
	377
	378	int nf_flow_snat_port(const struct flow_offload *flow,
	379	struct sk_buff *skb, unsigned int thoff,
	380	u8 protocol, enum flow_offload_tuple_dir dir)
	381	{
	382	struct flow_ports *hdr;
	383	__be16 port, new_port;
	384
	385	if (!pskb_may_pull(skb, thoff + sizeof(*hdr)) \|\|
	386	skb_try_make_writable(skb, thoff + sizeof(*hdr)))
	387	return -1;
	388
389	hdr = (void *)(skb_network_header(skb) + thoff);
390
391	switch (dir) {
392	case FLOW_OFFLOAD_DIR_ORIGINAL:
393	port = hdr->source;
394	new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port;
395	hdr->source = new_port;
396	break;
397	case FLOW_OFFLOAD_DIR_REPLY:
398	port = hdr->dest;
399	new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port;
400	hdr->dest = new_port;
401	break;
402	default:
403	return -1;
404	}
405
406	return nf_flow_nat_port(skb, thoff, protocol, port, new_port);
407	}
408	EXPORT_SYMBOL_GPL(nf_flow_snat_port);
409
410	int nf_flow_dnat_port(const struct flow_offload *flow,
411	struct sk_buff *skb, unsigned int thoff,
412	u8 protocol, enum flow_offload_tuple_dir dir)
413	{
414	struct flow_ports *hdr;
415	__be16 port, new_port;
416
417	if (!pskb_may_pull(skb, thoff + sizeof(*hdr)) \|\|
418	skb_try_make_writable(skb, thoff + sizeof(*hdr)))
419	return -1;
420
421	hdr = (void *)(skb_network_header(skb) + thoff);
422
423	switch (dir) {
424	case FLOW_OFFLOAD_DIR_ORIGINAL:
425	port = hdr->dest;
426	new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_port;
427	hdr->dest = new_port;
428	break;
429	case FLOW_OFFLOAD_DIR_REPLY:
430	port = hdr->source;
431	new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_port;
432	hdr->source = new_port;
433	break;
434	default:
435	return -1;
436	}
437
438	return nf_flow_nat_port(skb, thoff, protocol, port, new_port);
439	}
440	EXPORT_SYMBOL_GPL(nf_flow_dnat_port);
441
a268de77 FF	442	int nf_flow_table_init(struct nf_flowtable *flowtable)
	443	{
	444	int err;
	445
	446	INIT_DEFERRABLE_WORK(&flowtable->gc_work, nf_flow_offload_work_gc);
	447
	448	err = rhashtable_init(&flowtable->rhashtable,
	449	&nf_flow_offload_rhash_params);
	450	if (err < 0)
	451	return err;
	452
	453	queue_delayed_work(system_power_efficient_wq,
	454	&flowtable->gc_work, HZ);
	455
84453a90 FF	456	mutex_lock(&flowtable_lock);
	457	list_add(&flowtable->list, &flowtables);
	458	mutex_unlock(&flowtable_lock);
	459
a268de77 FF	460	return 0;
	461	}
	462	EXPORT_SYMBOL_GPL(nf_flow_table_init);
	463
c0ea1bcb PNA	464	static void nf_flow_table_do_cleanup(struct flow_offload flow, void data)
	465	{
	466	struct net_device *dev = data;
a3fb3698 TY	467	struct flow_offload_entry *e;
	468
	469	e = container_of(flow, struct flow_offload_entry, flow);
c0ea1bcb	470
59c466dd FF	471	if (!dev) {
59c466dd FF	472	flow_offload_teardown(flow);
c0ea1bcb	473	return;
59c466dd	474	}
a3fb3698 TY	475	if (net_eq(nf_ct_net(e->ct), dev_net(dev)) &&
	476	(flow->tuplehash[0].tuple.iifidx == dev->ifindex \|\|
	477	flow->tuplehash[1].tuple.iifidx == dev->ifindex))
59c466dd	478	flow_offload_dead(flow);
c0ea1bcb PNA	479	}
	480
	481	static void nf_flow_table_iterate_cleanup(struct nf_flowtable *flowtable,
84453a90	482	struct net_device *dev)
c0ea1bcb	483	{
84453a90	484	nf_flow_table_iterate(flowtable, nf_flow_table_do_cleanup, dev);
c0ea1bcb PNA	485	flush_delayed_work(&flowtable->gc_work);
	486	}
	487
5f1be84a	488	void nf_flow_table_cleanup(struct net_device *dev)
c0ea1bcb	489	{
84453a90 FF	490	struct nf_flowtable *flowtable;
	491
	492	mutex_lock(&flowtable_lock);
	493	list_for_each_entry(flowtable, &flowtables, list)
	494	nf_flow_table_iterate_cleanup(flowtable, dev);
	495	mutex_unlock(&flowtable_lock);
c0ea1bcb PNA	496	}
	497	EXPORT_SYMBOL_GPL(nf_flow_table_cleanup);
	498
b408c5b0 PNA	499	void nf_flow_table_free(struct nf_flowtable *flow_table)
b408c5b0 PNA	500	{
84453a90 FF	501	mutex_lock(&flowtable_lock);
	502	list_del(&flow_table->list);
	503	mutex_unlock(&flowtable_lock);
a268de77	504	cancel_delayed_work_sync(&flow_table->gc_work);
b408c5b0	505	nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL);
b9660987	506	nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, flow_table);
a268de77	507	rhashtable_destroy(&flow_table->rhashtable);
b408c5b0 PNA	508	}
	509	EXPORT_SYMBOL_GPL(nf_flow_table_free);
	510
ac2a6666 PNA	511	MODULE_LICENSE("GPL");
ac2a6666 PNA	512	MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");