#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/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;
};
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;
switch (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num) {
case NFPROTO_IPV4:
flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_v4 =
ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.in;
flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_v4 =
ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.in;
flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_v4 =
ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.in;
flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_v4 =
ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.in;
break;
case NFPROTO_IPV6:
flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_v6 =
ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.in6;
flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_v6 =
ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.in6;
flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_v6 =
ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.in6;
flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_v6 =
ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.in6;
break;
}
flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.l3proto =
ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.l4proto =
ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.l3proto =
ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.l4proto =
ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_cache =
route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].dst;
flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_cache =
route->tuple[FLOW_OFFLOAD_DIR_REPLY].dst;
flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port =
ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.tcp.port;
flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_port =
ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.tcp.port;
flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_port =
ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u.tcp.port;
flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port =
ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u.tcp.port;
flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dir =
FLOW_OFFLOAD_DIR_ORIGINAL;
flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dir =
FLOW_OFFLOAD_DIR_REPLY;
flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.iifidx =
route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].ifindex;
flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.oifidx =
route->tuple[FLOW_OFFLOAD_DIR_REPLY].ifindex;
flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.iifidx =
route->tuple[FLOW_OFFLOAD_DIR_REPLY].ifindex;
flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.oifidx =
route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].ifindex;
if (ct->status & IPS_SRC_NAT)
flow->flags |= FLOW_OFFLOAD_SNAT;
else 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);
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);
kfree(e);
}
EXPORT_SYMBOL_GPL(flow_offload_free);
void flow_offload_dead(struct flow_offload *flow)
{
flow->flags |= FLOW_OFFLOAD_DYING;
}
EXPORT_SYMBOL_GPL(flow_offload_dead);
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,
*flow_table->type->params);
rhashtable_insert_fast(&flow_table->rhashtable,
&flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node,
*flow_table->type->params);
return 0;
}
EXPORT_SYMBOL_GPL(flow_offload_add);
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,
*flow_table->type->params);
rhashtable_remove_fast(&flow_table->rhashtable,
&flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node,
*flow_table->type->params);
e = container_of(flow, struct flow_offload_entry, flow);
kfree_rcu(e, rcu_head);
}
EXPORT_SYMBOL_GPL(flow_offload_del);
struct flow_offload_tuple_rhash *
flow_offload_lookup(struct nf_flowtable *flow_table,
struct flow_offload_tuple *tuple)
{
return rhashtable_lookup_fast(&flow_table->rhashtable, tuple,
*flow_table->type->params);
}
EXPORT_SYMBOL_GPL(flow_offload_lookup);
static void nf_flow_release_ct(const struct flow_offload *flow)
{
struct flow_offload_entry *e;
e = container_of(flow, struct flow_offload_entry, flow);
nf_ct_delete(e->ct, 0, 0);
nf_ct_put(e->ct);
}
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;
err = rhashtable_walk_init(&flow_table->rhashtable, &hti, GFP_KERNEL);
if (err)
return err;
rhashtable_walk_start(&hti);
while ((tuplehash = rhashtable_walk_next(&hti))) {
if (IS_ERR(tuplehash)) {
err = PTR_ERR(tuplehash);
if (err != -EAGAIN)
goto out;
continue;
}
if (tuplehash->tuple.dir)
continue;
flow = container_of(tuplehash, struct flow_offload, tuplehash[0]);
iter(flow, data);
}
out:
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 inline bool nf_flow_is_dying(const struct flow_offload *flow)
{
return flow->flags & FLOW_OFFLOAD_DYING;
}
static int nf_flow_offload_gc_step(struct nf_flowtable *flow_table)
{
struct flow_offload_tuple_rhash *tuplehash;
struct rhashtable_iter hti;
struct flow_offload *flow;
int err;
err = rhashtable_walk_init(&flow_table->rhashtable, &hti, GFP_KERNEL);
if (err)
return 0;
rhashtable_walk_start(&hti);
while ((tuplehash = rhashtable_walk_next(&hti))) {
if (IS_ERR(tuplehash)) {
err = PTR_ERR(tuplehash);
if (err != -EAGAIN)
goto out;
continue;
}
if (tuplehash->tuple.dir)
continue;
flow = container_of(tuplehash, struct flow_offload, tuplehash[0]);
if (nf_flow_has_expired(flow) ||
nf_flow_is_dying(flow)) {
flow_offload_del(flow_table, flow);
nf_flow_release_ct(flow);
}
}
out:
rhashtable_walk_stop(&hti);
rhashtable_walk_exit(&hti);
return 1;
}
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);
}
EXPORT_SYMBOL_GPL(nf_flow_offload_work_gc);
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;
}
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,
};
EXPORT_SYMBOL_GPL(nf_flow_offload_rhash_params);
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);
static void nf_flow_table_do_cleanup(struct flow_offload *flow, void *data)
{
struct net_device *dev = data;
if (dev && flow->tuplehash[0].tuple.iifidx != dev->ifindex)
return;
flow_offload_dead(flow);
}
static void nf_flow_table_iterate_cleanup(struct nf_flowtable *flowtable,
void *data)
{
nf_flow_table_iterate(flowtable, nf_flow_table_do_cleanup, data);
flush_delayed_work(&flowtable->gc_work);
}
void nf_flow_table_cleanup(struct net *net, struct net_device *dev)
{
nft_flow_table_iterate(net, nf_flow_table_iterate_cleanup, dev);
}
EXPORT_SYMBOL_GPL(nf_flow_table_cleanup);
void nf_flow_table_free(struct nf_flowtable *flow_table)
{
nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL);
WARN_ON(!nf_flow_offload_gc_step(flow_table));
}
EXPORT_SYMBOL_GPL(nf_flow_table_free);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");