[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 *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 = route->tuple[dir].ifindex;
	ft->oifidx = route->tuple[!dir].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)
{
	flow->timeout = (u32)jiffies;

	rhashtable_insert_fast(&flow_table->rhashtable,
			       &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node,
			       nf_flow_offload_rhash_params);
	rhashtable_insert_fast(&flow_table->rhashtable,
			       &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node,
			       nf_flow_offload_rhash_params);
	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;
	int dir;

	tuplehash = rhashtable_lookup_fast(&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;

	return tuplehash;
}
EXPORT_SYMBOL_GPL(flow_offload_lookup);

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;
}
EXPORT_SYMBOL_GPL(nf_flow_table_iterate);

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 nf_flowtable *flow_table)
{
	struct flow_offload_tuple_rhash *tuplehash;
	struct rhashtable_iter hti;
	struct flow_offload *flow;

	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)
				break;
			continue;
		}
		if (tuplehash->tuple.dir)
			continue;

		flow = container_of(tuplehash, struct flow_offload, tuplehash[0]);

		if (nf_flow_has_expired(flow) ||
		    (flow->flags & (FLOW_OFFLOAD_DYING |
				    FLOW_OFFLOAD_TEARDOWN)))
			flow_offload_del(flow_table, flow);
	}
	rhashtable_walk_stop(&hti);
	rhashtable_walk_exit(&hti);
}

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_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;

	if (!dev) {
		flow_offload_teardown(flow);
		return;
	}

	if (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 *net, 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_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;
4f3780c0	31	struct dst_entry *dst = route->tuple[dir].dst;
047b300e FF	32
	33	ft->dir = dir;
	34
	35	switch (ctt->src.l3num) {
	36	case NFPROTO_IPV4:
	37	ft->src_v4 = ctt->src.u3.in;
	38	ft->dst_v4 = ctt->dst.u3.in;
4f3780c0	39	ft->mtu = ip_dst_mtu_maybe_forward(dst, true);
047b300e FF	40	break;
	41	case NFPROTO_IPV6:
	42	ft->src_v6 = ctt->src.u3.in6;
	43	ft->dst_v6 = ctt->dst.u3.in6;
4f3780c0	44	ft->mtu = ip6_dst_mtu_forward(dst);
047b300e FF	45	break;
	46	}
	47
	48	ft->l3proto = ctt->src.l3num;
	49	ft->l4proto = ctt->dst.protonum;
	50	ft->src_port = ctt->src.u.tcp.port;
	51	ft->dst_port = ctt->dst.u.tcp.port;
	52
	53	ft->iifidx = route->tuple[dir].ifindex;
	54	ft->oifidx = route->tuple[!dir].ifindex;
4f3780c0	55	ft->dst_cache = dst;
047b300e FF	56	}
047b300e FF	57
ac2a6666 PNA	58	struct flow_offload *
	59	flow_offload_alloc(struct nf_conn ct, struct nf_flow_route route)
	60	{
	61	struct flow_offload_entry *entry;
	62	struct flow_offload *flow;
	63
	64	if (unlikely(nf_ct_is_dying(ct) \|\|
	65	!atomic_inc_not_zero(&ct->ct_general.use)))
	66	return NULL;
	67
	68	entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
	69	if (!entry)
	70	goto err_ct_refcnt;
	71
	72	flow = &entry->flow;
	73
	74	if (!dst_hold_safe(route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].dst))
	75	goto err_dst_cache_original;
	76
	77	if (!dst_hold_safe(route->tuple[FLOW_OFFLOAD_DIR_REPLY].dst))
	78	goto err_dst_cache_reply;
	79
	80	entry->ct = ct;
	81
047b300e FF	82	flow_offload_fill_dir(flow, ct, route, FLOW_OFFLOAD_DIR_ORIGINAL);
047b300e FF	83	flow_offload_fill_dir(flow, ct, route, FLOW_OFFLOAD_DIR_REPLY);
ac2a6666 PNA	84
	85	if (ct->status & IPS_SRC_NAT)
	86	flow->flags \|= FLOW_OFFLOAD_SNAT;
df1e2025	87	if (ct->status & IPS_DST_NAT)
ac2a6666 PNA	88	flow->flags \|= FLOW_OFFLOAD_DNAT;
	89
	90	return flow;
	91
	92	err_dst_cache_reply:
	93	dst_release(route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].dst);
	94	err_dst_cache_original:
	95	kfree(entry);
	96	err_ct_refcnt:
	97	nf_ct_put(ct);
	98
	99	return NULL;
	100	}
	101	EXPORT_SYMBOL_GPL(flow_offload_alloc);
	102
da5984e5 FF	103	static void flow_offload_fixup_tcp(struct ip_ct_tcp *tcp)
	104	{
	105	tcp->state = TCP_CONNTRACK_ESTABLISHED;
	106	tcp->seen[0].td_maxwin = 0;
	107	tcp->seen[1].td_maxwin = 0;
	108	}
	109
e97d9404 FW	110	#define NF_FLOWTABLE_TCP_PICKUP_TIMEOUT (120 * HZ)
	111	#define NF_FLOWTABLE_UDP_PICKUP_TIMEOUT (30 * HZ)
	112
da5984e5 FF	113	static void flow_offload_fixup_ct_state(struct nf_conn *ct)
	114	{
	115	const struct nf_conntrack_l4proto *l4proto;
da5984e5 FF	116	unsigned int timeout;
	117	int l4num;
	118
	119	l4num = nf_ct_protonum(ct);
	120	if (l4num == IPPROTO_TCP)
	121	flow_offload_fixup_tcp(&ct->proto.tcp);
	122
dd2934a9	123	l4proto = __nf_ct_l4proto_find(l4num);
da5984e5 FF	124	if (!l4proto)
	125	return;
	126
da5984e5	127	if (l4num == IPPROTO_TCP)
e97d9404	128	timeout = NF_FLOWTABLE_TCP_PICKUP_TIMEOUT;
da5984e5	129	else if (l4num == IPPROTO_UDP)
e97d9404	130	timeout = NF_FLOWTABLE_UDP_PICKUP_TIMEOUT;
da5984e5 FF	131	else
	132	return;
	133
	134	ct->timeout = nfct_time_stamp + timeout;
	135	}
	136
ac2a6666 PNA	137	void flow_offload_free(struct flow_offload *flow)
	138	{
	139	struct flow_offload_entry *e;
	140
	141	dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_cache);
	142	dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_cache);
	143	e = container_of(flow, struct flow_offload_entry, flow);
da5984e5 FF	144	if (flow->flags & FLOW_OFFLOAD_DYING)
da5984e5 FF	145	nf_ct_delete(e->ct, 0, 0);
0ff90b6c FF	146	nf_ct_put(e->ct);
0ff90b6c FF	147	kfree_rcu(e, rcu_head);
ac2a6666 PNA	148	}
	149	EXPORT_SYMBOL_GPL(flow_offload_free);
	150
a268de77 FF	151	static u32 flow_offload_hash(const void *data, u32 len, u32 seed)
	152	{
	153	const struct flow_offload_tuple *tuple = data;
	154
	155	return jhash(tuple, offsetof(struct flow_offload_tuple, dir), seed);
	156	}
	157
	158	static u32 flow_offload_hash_obj(const void *data, u32 len, u32 seed)
	159	{
	160	const struct flow_offload_tuple_rhash *tuplehash = data;
	161
	162	return jhash(&tuplehash->tuple, offsetof(struct flow_offload_tuple, dir), seed);
	163	}
	164
	165	static int flow_offload_hash_cmp(struct rhashtable_compare_arg *arg,
	166	const void *ptr)
	167	{
	168	const struct flow_offload_tuple *tuple = arg->key;
	169	const struct flow_offload_tuple_rhash *x = ptr;
	170
	171	if (memcmp(&x->tuple, tuple, offsetof(struct flow_offload_tuple, dir)))
	172	return 1;
	173
	174	return 0;
	175	}
	176
	177	static const struct rhashtable_params nf_flow_offload_rhash_params = {
	178	.head_offset = offsetof(struct flow_offload_tuple_rhash, node),
	179	.hashfn = flow_offload_hash,
	180	.obj_hashfn = flow_offload_hash_obj,
	181	.obj_cmpfn = flow_offload_hash_cmp,
	182	.automatic_shrinking = true,
	183	};
	184
ac2a6666 PNA	185	int flow_offload_add(struct nf_flowtable flow_table, struct flow_offload flow)
	186	{
	187	flow->timeout = (u32)jiffies;
	188
	189	rhashtable_insert_fast(&flow_table->rhashtable,
	190	&flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node,
a268de77	191	nf_flow_offload_rhash_params);
ac2a6666 PNA	192	rhashtable_insert_fast(&flow_table->rhashtable,
ac2a6666 PNA	193	&flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node,
a268de77	194	nf_flow_offload_rhash_params);
ac2a6666 PNA	195	return 0;
	196	}
	197	EXPORT_SYMBOL_GPL(flow_offload_add);
	198
0ff90b6c FF	199	static void flow_offload_del(struct nf_flowtable *flow_table,
0ff90b6c FF	200	struct flow_offload *flow)
ac2a6666	201	{
da5984e5 FF	202	struct flow_offload_entry *e;
da5984e5 FF	203
ac2a6666 PNA	204	rhashtable_remove_fast(&flow_table->rhashtable,
ac2a6666 PNA	205	&flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node,
a268de77	206	nf_flow_offload_rhash_params);
ac2a6666 PNA	207	rhashtable_remove_fast(&flow_table->rhashtable,
ac2a6666 PNA	208	&flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node,
a268de77	209	nf_flow_offload_rhash_params);
ac2a6666	210
da5984e5 FF	211	e = container_of(flow, struct flow_offload_entry, flow);
	212	clear_bit(IPS_OFFLOAD_BIT, &e->ct->status);
	213
0ff90b6c	214	flow_offload_free(flow);
ac2a6666	215	}
ac2a6666	216
59c466dd FF	217	void flow_offload_teardown(struct flow_offload *flow)
59c466dd FF	218	{
da5984e5 FF	219	struct flow_offload_entry *e;
da5984e5 FF	220
59c466dd	221	flow->flags \|= FLOW_OFFLOAD_TEARDOWN;
da5984e5 FF	222
	223	e = container_of(flow, struct flow_offload_entry, flow);
	224	flow_offload_fixup_ct_state(e->ct);
59c466dd FF	225	}
	226	EXPORT_SYMBOL_GPL(flow_offload_teardown);
	227
ac2a6666 PNA	228	struct flow_offload_tuple_rhash *
	229	flow_offload_lookup(struct nf_flowtable *flow_table,
	230	struct flow_offload_tuple *tuple)
	231	{
ba03137f FF	232	struct flow_offload_tuple_rhash *tuplehash;
	233	struct flow_offload *flow;
	234	int dir;
	235
	236	tuplehash = rhashtable_lookup_fast(&flow_table->rhashtable, tuple,
	237	nf_flow_offload_rhash_params);
	238	if (!tuplehash)
	239	return NULL;
	240
	241	dir = tuplehash->tuple.dir;
	242	flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
	243	if (flow->flags & (FLOW_OFFLOAD_DYING \| FLOW_OFFLOAD_TEARDOWN))
	244	return NULL;
	245
	246	return tuplehash;
ac2a6666 PNA	247	}
	248	EXPORT_SYMBOL_GPL(flow_offload_lookup);
	249
ac2a6666 PNA	250	int nf_flow_table_iterate(struct nf_flowtable *flow_table,
	251	void (iter)(struct flow_offload flow, void *data),
	252	void *data)
	253	{
	254	struct flow_offload_tuple_rhash *tuplehash;
	255	struct rhashtable_iter hti;
	256	struct flow_offload *flow;
0de22baa	257	int err = 0;
ac2a6666	258
0de22baa	259	rhashtable_walk_enter(&flow_table->rhashtable, &hti);
ac2a6666 PNA	260	rhashtable_walk_start(&hti);
	261
	262	while ((tuplehash = rhashtable_walk_next(&hti))) {
	263	if (IS_ERR(tuplehash)) {
0de22baa TY	264	if (PTR_ERR(tuplehash) != -EAGAIN) {
	265	err = PTR_ERR(tuplehash);
	266	break;
	267	}
ac2a6666 PNA	268	continue;
	269	}
	270	if (tuplehash->tuple.dir)
	271	continue;
	272
	273	flow = container_of(tuplehash, struct flow_offload, tuplehash[0]);
	274
	275	iter(flow, data);
	276	}
ac2a6666 PNA	277	rhashtable_walk_stop(&hti);
	278	rhashtable_walk_exit(&hti);
	279
	280	return err;
	281	}
	282	EXPORT_SYMBOL_GPL(nf_flow_table_iterate);
	283
	284	static inline bool nf_flow_has_expired(const struct flow_offload *flow)
	285	{
	286	return (__s32)(flow->timeout - (u32)jiffies) <= 0;
	287	}
	288
0de22baa	289	static void nf_flow_offload_gc_step(struct nf_flowtable *flow_table)
ac2a6666 PNA	290	{
ac2a6666 PNA	291	struct flow_offload_tuple_rhash *tuplehash;
ac2a6666 PNA	292	struct rhashtable_iter hti;
ac2a6666 PNA	293	struct flow_offload *flow;
ac2a6666	294
0de22baa	295	rhashtable_walk_enter(&flow_table->rhashtable, &hti);
ac2a6666 PNA	296	rhashtable_walk_start(&hti);
	297
	298	while ((tuplehash = rhashtable_walk_next(&hti))) {
	299	if (IS_ERR(tuplehash)) {
0de22baa TY	300	if (PTR_ERR(tuplehash) != -EAGAIN)
0de22baa TY	301	break;
ac2a6666 PNA	302	continue;
	303	}
	304	if (tuplehash->tuple.dir)
	305	continue;
	306
	307	flow = container_of(tuplehash, struct flow_offload, tuplehash[0]);
	308
	309	if (nf_flow_has_expired(flow) \|\|
59c466dd FF	310	(flow->flags & (FLOW_OFFLOAD_DYING \|
59c466dd FF	311	FLOW_OFFLOAD_TEARDOWN)))
ac2a6666	312	flow_offload_del(flow_table, flow);
ac2a6666	313	}
ac2a6666 PNA	314	rhashtable_walk_stop(&hti);
ac2a6666 PNA	315	rhashtable_walk_exit(&hti);
b408c5b0 PNA	316	}
b408c5b0 PNA	317
a268de77	318	static void nf_flow_offload_work_gc(struct work_struct *work)
b408c5b0 PNA	319	{
	320	struct nf_flowtable *flow_table;
	321
	322	flow_table = container_of(work, struct nf_flowtable, gc_work.work);
	323	nf_flow_offload_gc_step(flow_table);
ac2a6666 PNA	324	queue_delayed_work(system_power_efficient_wq, &flow_table->gc_work, HZ);
ac2a6666 PNA	325	}
ac2a6666 PNA	326
	327	static int nf_flow_nat_port_tcp(struct sk_buff *skb, unsigned int thoff,
	328	__be16 port, __be16 new_port)
	329	{
	330	struct tcphdr *tcph;
	331
	332	if (!pskb_may_pull(skb, thoff + sizeof(*tcph)) \|\|
	333	skb_try_make_writable(skb, thoff + sizeof(*tcph)))
	334	return -1;
	335
	336	tcph = (void *)(skb_network_header(skb) + thoff);
	337	inet_proto_csum_replace2(&tcph->check, skb, port, new_port, true);
	338
	339	return 0;
	340	}
	341
	342	static int nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff,
	343	__be16 port, __be16 new_port)
	344	{
	345	struct udphdr *udph;
	346
	347	if (!pskb_may_pull(skb, thoff + sizeof(*udph)) \|\|
	348	skb_try_make_writable(skb, thoff + sizeof(*udph)))
	349	return -1;
	350
	351	udph = (void *)(skb_network_header(skb) + thoff);
	352	if (udph->check \|\| skb->ip_summed == CHECKSUM_PARTIAL) {
	353	inet_proto_csum_replace2(&udph->check, skb, port,
	354	new_port, true);
	355	if (!udph->check)
	356	udph->check = CSUM_MANGLED_0;
	357	}
	358
	359	return 0;
	360	}
	361
	362	static int nf_flow_nat_port(struct sk_buff *skb, unsigned int thoff,
	363	u8 protocol, __be16 port, __be16 new_port)
	364	{
	365	switch (protocol) {
	366	case IPPROTO_TCP:
	367	if (nf_flow_nat_port_tcp(skb, thoff, port, new_port) < 0)
	368	return NF_DROP;
	369	break;
	370	case IPPROTO_UDP:
	371	if (nf_flow_nat_port_udp(skb, thoff, port, new_port) < 0)
	372	return NF_DROP;
	373	break;
	374	}
	375
	376	return 0;
	377	}
	378
	379	int nf_flow_snat_port(const struct flow_offload *flow,
	380	struct sk_buff *skb, unsigned int thoff,
	381	u8 protocol, enum flow_offload_tuple_dir dir)
	382	{
	383	struct flow_ports *hdr;
	384	__be16 port, new_port;
	385
	386	if (!pskb_may_pull(skb, thoff + sizeof(*hdr)) \|\|
	387	skb_try_make_writable(skb, thoff + sizeof(*hdr)))
	388	return -1;
	389
390	hdr = (void *)(skb_network_header(skb) + thoff);
391
392	switch (dir) {
393	case FLOW_OFFLOAD_DIR_ORIGINAL:
394	port = hdr->source;
395	new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port;
396	hdr->source = new_port;
397	break;
398	case FLOW_OFFLOAD_DIR_REPLY:
399	port = hdr->dest;
400	new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port;
401	hdr->dest = new_port;
402	break;
403	default:
404	return -1;
405	}
406
407	return nf_flow_nat_port(skb, thoff, protocol, port, new_port);
408	}
409	EXPORT_SYMBOL_GPL(nf_flow_snat_port);
410
411	int nf_flow_dnat_port(const struct flow_offload *flow,
412	struct sk_buff *skb, unsigned int thoff,
413	u8 protocol, enum flow_offload_tuple_dir dir)
414	{
415	struct flow_ports *hdr;
416	__be16 port, new_port;
417
418	if (!pskb_may_pull(skb, thoff + sizeof(*hdr)) \|\|
419	skb_try_make_writable(skb, thoff + sizeof(*hdr)))
420	return -1;
421
422	hdr = (void *)(skb_network_header(skb) + thoff);
423
424	switch (dir) {
425	case FLOW_OFFLOAD_DIR_ORIGINAL:
426	port = hdr->dest;
427	new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_port;
428	hdr->dest = new_port;
429	break;
430	case FLOW_OFFLOAD_DIR_REPLY:
431	port = hdr->source;
432	new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_port;
433	hdr->source = new_port;
434	break;
435	default:
436	return -1;
437	}
438
439	return nf_flow_nat_port(skb, thoff, protocol, port, new_port);
440	}
441	EXPORT_SYMBOL_GPL(nf_flow_dnat_port);
442
a268de77 FF	443	int nf_flow_table_init(struct nf_flowtable *flowtable)
	444	{
	445	int err;
	446
	447	INIT_DEFERRABLE_WORK(&flowtable->gc_work, nf_flow_offload_work_gc);
	448
	449	err = rhashtable_init(&flowtable->rhashtable,
	450	&nf_flow_offload_rhash_params);
	451	if (err < 0)
	452	return err;
	453
	454	queue_delayed_work(system_power_efficient_wq,
	455	&flowtable->gc_work, HZ);
	456
84453a90 FF	457	mutex_lock(&flowtable_lock);
	458	list_add(&flowtable->list, &flowtables);
	459	mutex_unlock(&flowtable_lock);
	460
a268de77 FF	461	return 0;
	462	}
	463	EXPORT_SYMBOL_GPL(nf_flow_table_init);
	464
c0ea1bcb PNA	465	static void nf_flow_table_do_cleanup(struct flow_offload flow, void data)
	466	{
	467	struct net_device *dev = data;
	468
59c466dd FF	469	if (!dev) {
59c466dd FF	470	flow_offload_teardown(flow);
c0ea1bcb	471	return;
59c466dd	472	}
c0ea1bcb	473
59c466dd FF	474	if (flow->tuplehash[0].tuple.iifidx == dev->ifindex \|\|
	475	flow->tuplehash[1].tuple.iifidx == dev->ifindex)
	476	flow_offload_dead(flow);
c0ea1bcb PNA	477	}
	478
	479	static void nf_flow_table_iterate_cleanup(struct nf_flowtable *flowtable,
84453a90	480	struct net_device *dev)
c0ea1bcb	481	{
84453a90	482	nf_flow_table_iterate(flowtable, nf_flow_table_do_cleanup, dev);
c0ea1bcb PNA	483	flush_delayed_work(&flowtable->gc_work);
	484	}
	485
	486	void nf_flow_table_cleanup(struct net net, struct net_device dev)
	487	{
84453a90 FF	488	struct nf_flowtable *flowtable;
	489
	490	mutex_lock(&flowtable_lock);
	491	list_for_each_entry(flowtable, &flowtables, list)
	492	nf_flow_table_iterate_cleanup(flowtable, dev);
	493	mutex_unlock(&flowtable_lock);
c0ea1bcb PNA	494	}
	495	EXPORT_SYMBOL_GPL(nf_flow_table_cleanup);
	496
b408c5b0 PNA	497	void nf_flow_table_free(struct nf_flowtable *flow_table)
b408c5b0 PNA	498	{
84453a90 FF	499	mutex_lock(&flowtable_lock);
	500	list_del(&flow_table->list);
	501	mutex_unlock(&flowtable_lock);
a268de77	502	cancel_delayed_work_sync(&flow_table->gc_work);
b408c5b0	503	nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL);
0de22baa	504	nf_flow_offload_gc_step(flow_table);
a268de77	505	rhashtable_destroy(&flow_table->rhashtable);
b408c5b0 PNA	506	}
	507	EXPORT_SYMBOL_GPL(nf_flow_table_free);
	508
ac2a6666 PNA	509	MODULE_LICENSE("GPL");
ac2a6666 PNA	510	MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");