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// 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(ct->timeout) > (__s32)timeout)
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, __hash), 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, __hash), 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, __hash)))
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) ||
!test_and_clear_bit(NF_FLOW_HW_REFRESH, &flow->flags)))
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;
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;
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;
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;
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);
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");
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