#include <linux/etherdevice.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/workqueue.h>
#include <linux/spinlock.h>
#include <linux/netfilter/nf_conntrack_common.h>
#include <linux/netfilter/nf_tables.h>
#include <net/ip.h>
#include <net/flow.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_core.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_extend.h>
#include <net/netfilter/nf_flow_table.h>
struct nft_flow_offload {
struct nft_flowtable *flowtable;
};
static bool nft_flow_offload_skip(struct sk_buff *skb, int family)
{
if (skb_sec_path(skb))
return true;
if (family == NFPROTO_IPV4) {
const struct ip_options *opt;
opt = &(IPCB(skb)->opt);
if (unlikely(opt->optlen))
return true;
}
return false;
}
static void flow_offload_ct_tcp(struct nf_conn *ct)
{
spin_lock_bh(&ct->lock);
ct->proto.tcp.seen[0].flags |= IP_CT_TCP_FLAG_BE_LIBERAL;
ct->proto.tcp.seen[1].flags |= IP_CT_TCP_FLAG_BE_LIBERAL;
spin_unlock_bh(&ct->lock);
}
static void nft_flow_offload_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_flow_offload *priv = nft_expr_priv(expr);
struct nf_flowtable *flowtable = &priv->flowtable->data;
struct tcphdr _tcph, *tcph = NULL;
struct nf_flow_route route = {};
enum ip_conntrack_info ctinfo;
struct flow_offload *flow;
enum ip_conntrack_dir dir;
struct nf_conn *ct;
int ret;
if (nft_flow_offload_skip(pkt->skb, nft_pf(pkt)))
goto out;
ct = nf_ct_get(pkt->skb, &ctinfo);
if (!ct)
goto out;
switch (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum) {
case IPPROTO_TCP:
tcph = skb_header_pointer(pkt->skb, nft_thoff(pkt),
sizeof(_tcph), &_tcph);
if (unlikely(!tcph || tcph->fin || tcph->rst ||
!nf_conntrack_tcp_established(ct)))
goto out;
break;
case IPPROTO_UDP:
break;
#ifdef CONFIG_NF_CT_PROTO_GRE
case IPPROTO_GRE: {
struct nf_conntrack_tuple *tuple;
if (ct->status & IPS_NAT_MASK)
goto out;
tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
if (tuple->src.u.gre.key || tuple->dst.u.gre.key)
goto out;
break;
}
#endif
default:
goto out;
}
if (nf_ct_ext_exist(ct, NF_CT_EXT_HELPER) ||
ct->status & (IPS_SEQ_ADJUST | IPS_NAT_CLASH))
goto out;
if (!nf_ct_is_confirmed(ct))
goto out;
if (test_and_set_bit(IPS_OFFLOAD_BIT, &ct->status))
goto out;
dir = CTINFO2DIR(ctinfo);
if (nft_flow_route(pkt, ct, &route, dir, priv->flowtable) < 0)
goto err_flow_route;
flow = flow_offload_alloc(ct);
if (!flow)
goto err_flow_alloc;
flow_offload_route_init(flow, &route);
if (tcph)
flow_offload_ct_tcp(ct);
__set_bit(NF_FLOW_HW_BIDIRECTIONAL, &flow->flags);
ret = flow_offload_add(flowtable, flow);
if (ret < 0)
goto err_flow_add;
return;
err_flow_add:
flow_offload_free(flow);
err_flow_alloc:
dst_release(route.tuple[dir].dst);
dst_release(route.tuple[!dir].dst);
err_flow_route:
clear_bit(IPS_OFFLOAD_BIT, &ct->status);
out:
regs->verdict.code = NFT_BREAK;
}
static int nft_flow_offload_validate(const struct nft_ctx *ctx,
const struct nft_expr *expr)
{
unsigned int hook_mask = (1 << NF_INET_FORWARD);
if (ctx->family != NFPROTO_IPV4 &&
ctx->family != NFPROTO_IPV6 &&
ctx->family != NFPROTO_INET)
return -EOPNOTSUPP;
return nft_chain_validate_hooks(ctx->chain, hook_mask);
}
static const struct nla_policy nft_flow_offload_policy[NFTA_FLOW_MAX + 1] = {
[NFTA_FLOW_TABLE_NAME] = { .type = NLA_STRING,
.len = NFT_NAME_MAXLEN - 1 },
};
static int nft_flow_offload_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_flow_offload *priv = nft_expr_priv(expr);
u8 genmask = nft_genmask_next(ctx->net);
struct nft_flowtable *flowtable;
if (!tb[NFTA_FLOW_TABLE_NAME])
return -EINVAL;
flowtable = nft_flowtable_lookup(ctx->net, ctx->table,
tb[NFTA_FLOW_TABLE_NAME], genmask);
if (IS_ERR(flowtable))
return PTR_ERR(flowtable);
if (!nft_use_inc(&flowtable->use))
return -EMFILE;
priv->flowtable = flowtable;
return nf_ct_netns_get(ctx->net, ctx->family);
}
static void nft_flow_offload_deactivate(const struct nft_ctx *ctx,
const struct nft_expr *expr,
enum nft_trans_phase phase)
{
struct nft_flow_offload *priv = nft_expr_priv(expr);
nf_tables_deactivate_flowtable(ctx, priv->flowtable, phase);
}
static void nft_flow_offload_activate(const struct nft_ctx *ctx,
const struct nft_expr *expr)
{
struct nft_flow_offload *priv = nft_expr_priv(expr);
nft_use_inc_restore(&priv->flowtable->use);
}
static void nft_flow_offload_destroy(const struct nft_ctx *ctx,
const struct nft_expr *expr)
{
nf_ct_netns_put(ctx->net, ctx->family);
}
static int nft_flow_offload_dump(struct sk_buff *skb,
const struct nft_expr *expr, bool reset)
{
struct nft_flow_offload *priv = nft_expr_priv(expr);
if (nla_put_string(skb, NFTA_FLOW_TABLE_NAME, priv->flowtable->name))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static struct nft_expr_type nft_flow_offload_type;
static const struct nft_expr_ops nft_flow_offload_ops = {
.type = &nft_flow_offload_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_flow_offload)),
.eval = nft_flow_offload_eval,
.init = nft_flow_offload_init,
.activate = nft_flow_offload_activate,
.deactivate = nft_flow_offload_deactivate,
.destroy = nft_flow_offload_destroy,
.validate = nft_flow_offload_validate,
.dump = nft_flow_offload_dump,
.reduce = NFT_REDUCE_READONLY,
};
static struct nft_expr_type nft_flow_offload_type __read_mostly = {
.name = "flow_offload",
.ops = &nft_flow_offload_ops,
.policy = nft_flow_offload_policy,
.maxattr = NFTA_FLOW_MAX,
.owner = THIS_MODULE,
};
static int flow_offload_netdev_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
if (event != NETDEV_DOWN)
return NOTIFY_DONE;
nf_flow_table_cleanup(dev);
return NOTIFY_DONE;
}
static struct notifier_block flow_offload_netdev_notifier = {
.notifier_call = flow_offload_netdev_event,
};
static int __init nft_flow_offload_module_init(void)
{
int err;
err = register_netdevice_notifier(&flow_offload_netdev_notifier);
if (err)
goto err;
err = nft_register_expr(&nft_flow_offload_type);
if (err < 0)
goto register_expr;
return 0;
register_expr:
unregister_netdevice_notifier(&flow_offload_netdev_notifier);
err:
return err;
}
static void __exit nft_flow_offload_module_exit(void)
{
nft_unregister_expr(&nft_flow_offload_type);
unregister_netdevice_notifier(&flow_offload_netdev_notifier);
}
module_init(nft_flow_offload_module_init);
module_exit(nft_flow_offload_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
MODULE_ALIAS_NFT_EXPR("flow_offload");
MODULE_DESCRIPTION("nftables hardware flow offload module");
