/* SPDX-License-Identifier: GPL-2.0 */
|
#include <linux/module.h>
|
#include <linux/netfilter/nf_tables.h>
|
#include <net/netfilter/nf_tables.h>
|
#include <net/netfilter/nf_tables_core.h>
|
#include <net/netfilter/nf_tproxy.h>
|
#include <net/inet_sock.h>
|
#include <net/tcp.h>
|
#include <linux/if_ether.h>
|
#include <net/netfilter/ipv4/nf_defrag_ipv4.h>
|
#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
|
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
|
#endif
|
|
struct nft_tproxy {
|
u8 sreg_addr;
|
u8 sreg_port;
|
u8 family;
|
};
|
|
static void nft_tproxy_eval_v4(const struct nft_expr *expr,
|
struct nft_regs *regs,
|
const struct nft_pktinfo *pkt)
|
{
|
const struct nft_tproxy *priv = nft_expr_priv(expr);
|
struct sk_buff *skb = pkt->skb;
|
const struct iphdr *iph = ip_hdr(skb);
|
struct udphdr _hdr, *hp;
|
__be32 taddr = 0;
|
__be16 tport = 0;
|
struct sock *sk;
|
|
if (pkt->tprot != IPPROTO_TCP &&
|
pkt->tprot != IPPROTO_UDP) {
|
regs->verdict.code = NFT_BREAK;
|
return;
|
}
|
|
hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
|
if (!hp) {
|
regs->verdict.code = NFT_BREAK;
|
return;
|
}
|
|
/* check if there's an ongoing connection on the packet addresses, this
|
* happens if the redirect already happened and the current packet
|
* belongs to an already established connection
|
*/
|
sk = nf_tproxy_get_sock_v4(nft_net(pkt), skb, iph->protocol,
|
iph->saddr, iph->daddr,
|
hp->source, hp->dest,
|
skb->dev, NF_TPROXY_LOOKUP_ESTABLISHED);
|
|
if (priv->sreg_addr)
|
taddr = regs->data[priv->sreg_addr];
|
taddr = nf_tproxy_laddr4(skb, taddr, iph->daddr);
|
|
if (priv->sreg_port)
|
tport = nft_reg_load16(®s->data[priv->sreg_port]);
|
if (!tport)
|
tport = hp->dest;
|
|
/* UDP has no TCP_TIME_WAIT state, so we never enter here */
|
if (sk && sk->sk_state == TCP_TIME_WAIT) {
|
/* reopening a TIME_WAIT connection needs special handling */
|
sk = nf_tproxy_handle_time_wait4(nft_net(pkt), skb, taddr, tport, sk);
|
} else if (!sk) {
|
/* no, there's no established connection, check if
|
* there's a listener on the redirected addr/port
|
*/
|
sk = nf_tproxy_get_sock_v4(nft_net(pkt), skb, iph->protocol,
|
iph->saddr, taddr,
|
hp->source, tport,
|
skb->dev, NF_TPROXY_LOOKUP_LISTENER);
|
}
|
|
if (sk && nf_tproxy_sk_is_transparent(sk))
|
nf_tproxy_assign_sock(skb, sk);
|
else
|
regs->verdict.code = NFT_BREAK;
|
}
|
|
#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
|
static void nft_tproxy_eval_v6(const struct nft_expr *expr,
|
struct nft_regs *regs,
|
const struct nft_pktinfo *pkt)
|
{
|
const struct nft_tproxy *priv = nft_expr_priv(expr);
|
struct sk_buff *skb = pkt->skb;
|
const struct ipv6hdr *iph = ipv6_hdr(skb);
|
struct in6_addr taddr;
|
int thoff = pkt->xt.thoff;
|
struct udphdr _hdr, *hp;
|
__be16 tport = 0;
|
struct sock *sk;
|
int l4proto;
|
|
memset(&taddr, 0, sizeof(taddr));
|
|
if (pkt->tprot != IPPROTO_TCP &&
|
pkt->tprot != IPPROTO_UDP) {
|
regs->verdict.code = NFT_BREAK;
|
return;
|
}
|
l4proto = pkt->tprot;
|
|
hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
|
if (hp == NULL) {
|
regs->verdict.code = NFT_BREAK;
|
return;
|
}
|
|
/* check if there's an ongoing connection on the packet addresses, this
|
* happens if the redirect already happened and the current packet
|
* belongs to an already established connection
|
*/
|
sk = nf_tproxy_get_sock_v6(nft_net(pkt), skb, thoff, l4proto,
|
&iph->saddr, &iph->daddr,
|
hp->source, hp->dest,
|
nft_in(pkt), NF_TPROXY_LOOKUP_ESTABLISHED);
|
|
if (priv->sreg_addr)
|
memcpy(&taddr, ®s->data[priv->sreg_addr], sizeof(taddr));
|
taddr = *nf_tproxy_laddr6(skb, &taddr, &iph->daddr);
|
|
if (priv->sreg_port)
|
tport = nft_reg_load16(®s->data[priv->sreg_port]);
|
if (!tport)
|
tport = hp->dest;
|
|
/* UDP has no TCP_TIME_WAIT state, so we never enter here */
|
if (sk && sk->sk_state == TCP_TIME_WAIT) {
|
/* reopening a TIME_WAIT connection needs special handling */
|
sk = nf_tproxy_handle_time_wait6(skb, l4proto, thoff,
|
nft_net(pkt),
|
&taddr,
|
tport,
|
sk);
|
} else if (!sk) {
|
/* no there's no established connection, check if
|
* there's a listener on the redirected addr/port
|
*/
|
sk = nf_tproxy_get_sock_v6(nft_net(pkt), skb, thoff,
|
l4proto, &iph->saddr, &taddr,
|
hp->source, tport,
|
nft_in(pkt), NF_TPROXY_LOOKUP_LISTENER);
|
}
|
|
/* NOTE: assign_sock consumes our sk reference */
|
if (sk && nf_tproxy_sk_is_transparent(sk))
|
nf_tproxy_assign_sock(skb, sk);
|
else
|
regs->verdict.code = NFT_BREAK;
|
}
|
#endif
|
|
static void nft_tproxy_eval(const struct nft_expr *expr,
|
struct nft_regs *regs,
|
const struct nft_pktinfo *pkt)
|
{
|
const struct nft_tproxy *priv = nft_expr_priv(expr);
|
|
switch (nft_pf(pkt)) {
|
case NFPROTO_IPV4:
|
switch (priv->family) {
|
case NFPROTO_IPV4:
|
case NFPROTO_UNSPEC:
|
nft_tproxy_eval_v4(expr, regs, pkt);
|
return;
|
}
|
break;
|
#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
|
case NFPROTO_IPV6:
|
switch (priv->family) {
|
case NFPROTO_IPV6:
|
case NFPROTO_UNSPEC:
|
nft_tproxy_eval_v6(expr, regs, pkt);
|
return;
|
}
|
#endif
|
}
|
regs->verdict.code = NFT_BREAK;
|
}
|
|
static const struct nla_policy nft_tproxy_policy[NFTA_TPROXY_MAX + 1] = {
|
[NFTA_TPROXY_FAMILY] = { .type = NLA_U32 },
|
[NFTA_TPROXY_REG_ADDR] = { .type = NLA_U32 },
|
[NFTA_TPROXY_REG_PORT] = { .type = NLA_U32 },
|
};
|
|
static int nft_tproxy_init(const struct nft_ctx *ctx,
|
const struct nft_expr *expr,
|
const struct nlattr * const tb[])
|
{
|
struct nft_tproxy *priv = nft_expr_priv(expr);
|
unsigned int alen = 0;
|
int err;
|
|
if (!tb[NFTA_TPROXY_FAMILY] ||
|
(!tb[NFTA_TPROXY_REG_ADDR] && !tb[NFTA_TPROXY_REG_PORT]))
|
return -EINVAL;
|
|
priv->family = ntohl(nla_get_be32(tb[NFTA_TPROXY_FAMILY]));
|
|
switch (ctx->family) {
|
case NFPROTO_IPV4:
|
if (priv->family != NFPROTO_IPV4)
|
return -EINVAL;
|
break;
|
#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
|
case NFPROTO_IPV6:
|
if (priv->family != NFPROTO_IPV6)
|
return -EINVAL;
|
break;
|
#endif
|
case NFPROTO_INET:
|
break;
|
default:
|
return -EOPNOTSUPP;
|
}
|
|
/* Address is specified but the rule family is not set accordingly */
|
if (priv->family == NFPROTO_UNSPEC && tb[NFTA_TPROXY_REG_ADDR])
|
return -EINVAL;
|
|
switch (priv->family) {
|
case NFPROTO_IPV4:
|
alen = sizeof_field(union nf_inet_addr, in);
|
err = nf_defrag_ipv4_enable(ctx->net);
|
if (err)
|
return err;
|
break;
|
#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
|
case NFPROTO_IPV6:
|
alen = sizeof_field(union nf_inet_addr, in6);
|
err = nf_defrag_ipv6_enable(ctx->net);
|
if (err)
|
return err;
|
break;
|
#endif
|
case NFPROTO_UNSPEC:
|
/* No address is specified here */
|
err = nf_defrag_ipv4_enable(ctx->net);
|
if (err)
|
return err;
|
#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
|
err = nf_defrag_ipv6_enable(ctx->net);
|
if (err)
|
return err;
|
#endif
|
break;
|
default:
|
return -EOPNOTSUPP;
|
}
|
|
if (tb[NFTA_TPROXY_REG_ADDR]) {
|
err = nft_parse_register_load(tb[NFTA_TPROXY_REG_ADDR],
|
&priv->sreg_addr, alen);
|
if (err < 0)
|
return err;
|
}
|
|
if (tb[NFTA_TPROXY_REG_PORT]) {
|
err = nft_parse_register_load(tb[NFTA_TPROXY_REG_PORT],
|
&priv->sreg_port, sizeof(u16));
|
if (err < 0)
|
return err;
|
}
|
|
return 0;
|
}
|
|
static int nft_tproxy_dump(struct sk_buff *skb,
|
const struct nft_expr *expr)
|
{
|
const struct nft_tproxy *priv = nft_expr_priv(expr);
|
|
if (nla_put_be32(skb, NFTA_TPROXY_FAMILY, htonl(priv->family)))
|
return -1;
|
|
if (priv->sreg_addr &&
|
nft_dump_register(skb, NFTA_TPROXY_REG_ADDR, priv->sreg_addr))
|
return -1;
|
|
if (priv->sreg_port &&
|
nft_dump_register(skb, NFTA_TPROXY_REG_PORT, priv->sreg_port))
|
return -1;
|
|
return 0;
|
}
|
|
static struct nft_expr_type nft_tproxy_type;
|
static const struct nft_expr_ops nft_tproxy_ops = {
|
.type = &nft_tproxy_type,
|
.size = NFT_EXPR_SIZE(sizeof(struct nft_tproxy)),
|
.eval = nft_tproxy_eval,
|
.init = nft_tproxy_init,
|
.dump = nft_tproxy_dump,
|
};
|
|
static struct nft_expr_type nft_tproxy_type __read_mostly = {
|
.name = "tproxy",
|
.ops = &nft_tproxy_ops,
|
.policy = nft_tproxy_policy,
|
.maxattr = NFTA_TPROXY_MAX,
|
.owner = THIS_MODULE,
|
};
|
|
static int __init nft_tproxy_module_init(void)
|
{
|
return nft_register_expr(&nft_tproxy_type);
|
}
|
|
static void __exit nft_tproxy_module_exit(void)
|
{
|
nft_unregister_expr(&nft_tproxy_type);
|
}
|
|
module_init(nft_tproxy_module_init);
|
module_exit(nft_tproxy_module_exit);
|
|
MODULE_LICENSE("GPL");
|
MODULE_AUTHOR("Máté Eckl");
|
MODULE_DESCRIPTION("nf_tables tproxy support module");
|
MODULE_ALIAS_NFT_EXPR("tproxy");
|
