new file mode 100644
@@ -0,0 +1,113 @@
+#ifndef _NF_TPROXY_H_
+#define _NF_TPROXY_H_
+
+#include <net/tcp.h>
+
+enum nf_tproxy_lookup_t {
+ NF_TPROXY_LOOKUP_LISTENER,
+ NF_TPROXY_LOOKUP_ESTABLISHED,
+};
+
+static inline bool nf_tproxy_sk_is_transparent(struct sock *sk)
+{
+ if (inet_sk_transparent(sk))
+ return true;
+
+ sock_gen_put(sk);
+ return false;
+}
+
+__be32 nf_tproxy_laddr4(struct sk_buff *skb, __be32 user_laddr, __be32 daddr);
+
+/**
+ * nf_tproxy_handle_time_wait4 - handle IPv4 TCP TIME_WAIT reopen redirections
+ * @skb: The skb being processed.
+ * @laddr: IPv4 address to redirect to or zero.
+ * @lport: TCP port to redirect to or zero.
+ * @sk: The TIME_WAIT TCP socket found by the lookup.
+ *
+ * We have to handle SYN packets arriving to TIME_WAIT sockets
+ * differently: instead of reopening the connection we should rather
+ * redirect the new connection to the proxy if there's a listener
+ * socket present.
+ *
+ * nf_tproxy_handle_time_wait4() consumes the socket reference passed in.
+ *
+ * Returns the listener socket if there's one, the TIME_WAIT socket if
+ * no such listener is found, or NULL if the TCP header is incomplete.
+ */
+struct sock *
+nf_tproxy_handle_time_wait4(struct net *net, struct sk_buff *skb,
+ __be32 laddr, __be16 lport, struct sock *sk);
+
+/*
+ * This is used when the user wants to intercept a connection matching
+ * an explicit iptables rule. In this case the sockets are assumed
+ * matching in preference order:
+ *
+ * - match: if there's a fully established connection matching the
+ * _packet_ tuple, it is returned, assuming the redirection
+ * already took place and we process a packet belonging to an
+ * established connection
+ *
+ * - match: if there's a listening socket matching the redirection
+ * (e.g. on-port & on-ip of the connection), it is returned,
+ * regardless if it was bound to 0.0.0.0 or an explicit
+ * address. The reasoning is that if there's an explicit rule, it
+ * does not really matter if the listener is bound to an interface
+ * or to 0. The user already stated that he wants redirection
+ * (since he added the rule).
+ *
+ * Please note that there's an overlap between what a TPROXY target
+ * and a socket match will match. Normally if you have both rules the
+ * "socket" match will be the first one, effectively all packets
+ * belonging to established connections going through that one.
+ */
+struct sock *
+nf_tproxy_get_sock_v4(struct net *net, struct sk_buff *skb, void *hp,
+ const u8 protocol,
+ const __be32 saddr, const __be32 daddr,
+ const __be16 sport, const __be16 dport,
+ const struct net_device *in,
+ const enum nf_tproxy_lookup_t lookup_type);
+
+const struct in6_addr *
+nf_tproxy_laddr6(struct sk_buff *skb, const struct in6_addr *user_laddr,
+ const struct in6_addr *daddr);
+
+/**
+ * nf_tproxy_handle_time_wait6 - handle IPv6 TCP TIME_WAIT reopen redirections
+ * @skb: The skb being processed.
+ * @tproto: Transport protocol.
+ * @thoff: Transport protocol header offset.
+ * @net: Network namespace.
+ * @laddr: IPv6 address to redirect to.
+ * @lport: TCP port to redirect to or zero.
+ * @sk: The TIME_WAIT TCP socket found by the lookup.
+ *
+ * We have to handle SYN packets arriving to TIME_WAIT sockets
+ * differently: instead of reopening the connection we should rather
+ * redirect the new connection to the proxy if there's a listener
+ * socket present.
+ *
+ * nf_tproxy_handle_time_wait6() consumes the socket reference passed in.
+ *
+ * Returns the listener socket if there's one, the TIME_WAIT socket if
+ * no such listener is found, or NULL if the TCP header is incomplete.
+ */
+struct sock *
+nf_tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff,
+ struct net *net,
+ const struct in6_addr *laddr,
+ const __be16 lport,
+ struct sock *sk);
+
+struct sock *
+nf_tproxy_get_sock_v6(struct net *net, struct sk_buff *skb, int thoff, void *hp,
+ const u8 protocol,
+ const struct in6_addr *saddr, const struct in6_addr *daddr,
+ const __be16 sport, const __be16 dport,
+ const struct net_device *in,
+ const enum nf_tproxy_lookup_t lookup_type);
+
+#endif // _NF_TPROXY_H_
@@ -29,7 +29,13 @@ config NF_SOCKET_IPV4
tristate "IPv4 socket lookup support"
help
This option enables the IPv4 socket lookup infrastructure. This is
- is required by the iptables socket match.
+ is required by the {ip,nf}tables socket match.
+
+config NF_TPROXY_IPV4
+ tristate "IPv4 tproxy support"
+ help
+ This option enables tranparent proxy support for IPv4. This is required
+ by the iptables TPROXY targer.
if NF_TABLES
@@ -17,6 +17,7 @@ obj-$(CONFIG_NF_NAT_IPV4) += nf_nat_ipv4.o
obj-$(CONFIG_NF_DEFRAG_IPV4) += nf_defrag_ipv4.o
obj-$(CONFIG_NF_SOCKET_IPV4) += nf_socket_ipv4.o
+obj-$(CONFIG_NF_TPROXY_IPV4) += nf_tproxy_ipv4.o
# logging
obj-$(CONFIG_NF_LOG_ARP) += nf_log_arp.o
new file mode 100644
@@ -0,0 +1,147 @@
+/*
+ * Copyright (C) 2007-2008 BalaBit IT Ltd.
+ * Author: Krisztian Kovacs
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <net/netfilter/nf_tproxy.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/inet_sock.h>
+#include <linux/ip.h>
+#include <net/checksum.h>
+#include <net/udp.h>
+#include <net/tcp.h>
+#include <linux/inetdevice.h>
+
+struct sock *
+nf_tproxy_handle_time_wait4(struct net *net, struct sk_buff *skb,
+ __be32 laddr, __be16 lport, struct sock *sk)
+{
+ const struct iphdr *iph = ip_hdr(skb);
+ struct tcphdr _hdr, *hp;
+
+ hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
+ if (hp == NULL) {
+ inet_twsk_put(inet_twsk(sk));
+ return NULL;
+ }
+
+ if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
+ /* SYN to a TIME_WAIT socket, we'd rather redirect it
+ * to a listener socket if there's one */
+ struct sock *sk2;
+
+ sk2 = nf_tproxy_get_sock_v4(net, skb, hp, iph->protocol,
+ iph->saddr, laddr ? laddr : iph->daddr,
+ hp->source, lport ? lport : hp->dest,
+ skb->dev, NF_TPROXY_LOOKUP_LISTENER);
+ if (sk2) {
+ inet_twsk_deschedule_put(inet_twsk(sk));
+ sk = sk2;
+ }
+ }
+
+ return sk;
+}
+EXPORT_SYMBOL_GPL(nf_tproxy_handle_time_wait4);
+
+__be32 nf_tproxy_laddr4(struct sk_buff *skb, __be32 user_laddr, __be32 daddr)
+{
+ struct in_device *indev;
+ __be32 laddr;
+
+ if (user_laddr)
+ return user_laddr;
+
+ laddr = 0;
+ indev = __in_dev_get_rcu(skb->dev);
+ for_primary_ifa(indev) {
+ laddr = ifa->ifa_local;
+ break;
+ } endfor_ifa(indev);
+
+ return laddr ? laddr : daddr;
+}
+EXPORT_SYMBOL_GPL(nf_tproxy_laddr4);
+
+struct sock *
+nf_tproxy_get_sock_v4(struct net *net, struct sk_buff *skb, void *hp,
+ const u8 protocol,
+ const __be32 saddr, const __be32 daddr,
+ const __be16 sport, const __be16 dport,
+ const struct net_device *in,
+ const enum nf_tproxy_lookup_t lookup_type)
+{
+ struct sock *sk;
+ struct tcphdr *tcph;
+
+ switch (protocol) {
+ case IPPROTO_TCP:
+ switch (lookup_type) {
+ case NF_TPROXY_LOOKUP_LISTENER:
+ tcph = hp;
+ sk = inet_lookup_listener(net, &tcp_hashinfo, skb,
+ ip_hdrlen(skb) +
+ __tcp_hdrlen(tcph),
+ saddr, sport,
+ daddr, dport,
+ in->ifindex, 0);
+
+ if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
+ sk = NULL;
+ /* NOTE: we return listeners even if bound to
+ * 0.0.0.0, those are filtered out in
+ * xt_socket, since xt_TPROXY needs 0 bound
+ * listeners too
+ */
+ break;
+ case NF_TPROXY_LOOKUP_ESTABLISHED:
+ sk = inet_lookup_established(net, &tcp_hashinfo,
+ saddr, sport, daddr, dport,
+ in->ifindex);
+ break;
+ default:
+ BUG();
+ }
+ break;
+ case IPPROTO_UDP:
+ sk = udp4_lib_lookup(net, saddr, sport, daddr, dport,
+ in->ifindex);
+ if (sk) {
+ int connected = (sk->sk_state == TCP_ESTABLISHED);
+ int wildcard = (inet_sk(sk)->inet_rcv_saddr == 0);
+
+ /* NOTE: we return listeners even if bound to
+ * 0.0.0.0, those are filtered out in
+ * xt_socket, since xt_TPROXY needs 0 bound
+ * listeners too
+ */
+ if ((lookup_type == NF_TPROXY_LOOKUP_ESTABLISHED &&
+ (!connected || wildcard)) ||
+ (lookup_type == NF_TPROXY_LOOKUP_LISTENER && connected)) {
+ sock_put(sk);
+ sk = NULL;
+ }
+ }
+ break;
+ default:
+ WARN_ON(1);
+ sk = NULL;
+ }
+
+ pr_debug("tproxy socket lookup: proto %u %08x:%u -> %08x:%u, lookup type: %d, sock %p\n",
+ protocol, ntohl(saddr), ntohs(sport), ntohl(daddr), ntohs(dport), lookup_type, sk);
+
+ return sk;
+}
+EXPORT_SYMBOL_GPL(nf_tproxy_get_sock_v4);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs");
+MODULE_DESCRIPTION("Netfilter IPv4 transparent proxy support");
@@ -29,7 +29,13 @@ config NF_SOCKET_IPV6
tristate "IPv6 socket lookup support"
help
This option enables the IPv6 socket lookup infrastructure. This
- is used by the ip6tables socket match.
+ is used by the {ip6,nf}tables socket match.
+
+config NF_TPROXY_IPV6
+ tristate "IPv6 tproxy support"
+ help
+ This option enables IPv6 transparent proxy support. This is used by
+ the ip6tables TPROXY target.
if NF_TABLES
@@ -26,6 +26,7 @@ nf_defrag_ipv6-y := nf_defrag_ipv6_hooks.o nf_conntrack_reasm.o
obj-$(CONFIG_NF_DEFRAG_IPV6) += nf_defrag_ipv6.o
obj-$(CONFIG_NF_SOCKET_IPV6) += nf_socket_ipv6.o
+obj-$(CONFIG_NF_TPROXY_IPV6) += nf_tproxy_ipv6.o
# logging
obj-$(CONFIG_NF_LOG_IPV6) += nf_log_ipv6.o
new file mode 100644
@@ -0,0 +1,146 @@
+#include <net/netfilter/nf_tproxy.h>
+#include <linux/module.h>
+#include <net/inet6_hashtables.h>
+#include <net/addrconf.h>
+#include <net/udp.h>
+#include <net/tcp.h>
+
+const struct in6_addr *
+nf_tproxy_laddr6(struct sk_buff *skb, const struct in6_addr *user_laddr,
+ const struct in6_addr *daddr)
+{
+ struct inet6_dev *indev;
+ struct inet6_ifaddr *ifa;
+ struct in6_addr *laddr;
+
+ if (!ipv6_addr_any(user_laddr))
+ return user_laddr;
+ laddr = NULL;
+
+ indev = __in6_dev_get(skb->dev);
+ if (indev) {
+ read_lock_bh(&indev->lock);
+ list_for_each_entry(ifa, &indev->addr_list, if_list) {
+ if (ifa->flags & (IFA_F_TENTATIVE | IFA_F_DEPRECATED))
+ continue;
+
+ laddr = &ifa->addr;
+ break;
+ }
+ read_unlock_bh(&indev->lock);
+ }
+
+ return laddr ? laddr : daddr;
+}
+EXPORT_SYMBOL_GPL(nf_tproxy_laddr6);
+
+struct sock *
+nf_tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff,
+ struct net *net,
+ const struct in6_addr *laddr,
+ const __be16 lport,
+ struct sock *sk)
+{
+ const struct ipv6hdr *iph = ipv6_hdr(skb);
+ struct tcphdr _hdr, *hp;
+
+ hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
+ if (hp == NULL) {
+ inet_twsk_put(inet_twsk(sk));
+ return NULL;
+ }
+
+ if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
+ /* SYN to a TIME_WAIT socket, we'd rather redirect it
+ * to a listener socket if there's one */
+ struct sock *sk2;
+
+ sk2 = nf_tproxy_get_sock_v6(net, skb, thoff, hp, tproto,
+ &iph->saddr,
+ nf_tproxy_laddr6(skb, laddr, &iph->daddr),
+ hp->source,
+ lport ? lport : hp->dest,
+ skb->dev, NF_TPROXY_LOOKUP_LISTENER);
+ if (sk2) {
+ inet_twsk_deschedule_put(inet_twsk(sk));
+ sk = sk2;
+ }
+ }
+
+ return sk;
+}
+EXPORT_SYMBOL_GPL(nf_tproxy_handle_time_wait6);
+
+struct sock *
+nf_tproxy_get_sock_v6(struct net *net, struct sk_buff *skb, int thoff, void *hp,
+ const u8 protocol,
+ const struct in6_addr *saddr, const struct in6_addr *daddr,
+ const __be16 sport, const __be16 dport,
+ const struct net_device *in,
+ const enum nf_tproxy_lookup_t lookup_type)
+{
+ struct sock *sk;
+ struct tcphdr *tcph;
+
+ switch (protocol) {
+ case IPPROTO_TCP:
+ switch (lookup_type) {
+ case NF_TPROXY_LOOKUP_LISTENER:
+ tcph = hp;
+ sk = inet6_lookup_listener(net, &tcp_hashinfo, skb,
+ thoff + __tcp_hdrlen(tcph),
+ saddr, sport,
+ daddr, ntohs(dport),
+ in->ifindex, 0);
+
+ if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
+ sk = NULL;
+ /* NOTE: we return listeners even if bound to
+ * 0.0.0.0, those are filtered out in
+ * xt_socket, since xt_TPROXY needs 0 bound
+ * listeners too
+ */
+ break;
+ case NF_TPROXY_LOOKUP_ESTABLISHED:
+ sk = __inet6_lookup_established(net, &tcp_hashinfo,
+ saddr, sport, daddr, ntohs(dport),
+ in->ifindex, 0);
+ break;
+ default:
+ BUG();
+ }
+ break;
+ case IPPROTO_UDP:
+ sk = udp6_lib_lookup(net, saddr, sport, daddr, dport,
+ in->ifindex);
+ if (sk) {
+ int connected = (sk->sk_state == TCP_ESTABLISHED);
+ int wildcard = ipv6_addr_any(&sk->sk_v6_rcv_saddr);
+
+ /* NOTE: we return listeners even if bound to
+ * 0.0.0.0, those are filtered out in
+ * xt_socket, since xt_TPROXY needs 0 bound
+ * listeners too
+ */
+ if ((lookup_type == NF_TPROXY_LOOKUP_ESTABLISHED && (!connected || wildcard)) ||
+ (lookup_type == NF_TPROXY_LOOKUP_LISTENER && connected)) {
+ sock_put(sk);
+ sk = NULL;
+ }
+ }
+ break;
+ default:
+ WARN_ON(1);
+ sk = NULL;
+ }
+
+ pr_debug("tproxy socket lookup: proto %u %pI6:%u -> %pI6:%u, lookup type: %d, sock %p\n",
+ protocol, saddr, ntohs(sport), daddr, ntohs(dport), lookup_type, sk);
+
+ return sk;
+}
+EXPORT_SYMBOL_GPL(nf_tproxy_get_sock_v6);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs");
+MODULE_DESCRIPTION("Netfilter IPv4 transparent proxy support");
@@ -989,6 +989,8 @@ config NETFILTER_XT_TARGET_TPROXY
depends on IP_NF_MANGLE
select NF_DEFRAG_IPV4
select NF_DEFRAG_IPV6 if IP6_NF_IPTABLES != n
+ select NF_TPROXY_IPV4
+ select NF_TPROXY_IPV6 if IP6_NF_IPTABLES
help
This option adds a `TPROXY' target, which is somewhat similar to
REDIRECT. It can only be used in the mangle table and is useful
@@ -33,253 +33,9 @@
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
#endif
+#include <net/netfilter/nf_tproxy.h>
#include <linux/netfilter/xt_TPROXY.h>
-enum nf_tproxy_lookup_t {
- NFT_LOOKUP_LISTENER,
- NFT_LOOKUP_ESTABLISHED,
-};
-
-static bool tproxy_sk_is_transparent(struct sock *sk)
-{
- if (inet_sk_transparent(sk))
- return true;
-
- sock_gen_put(sk);
- return false;
-}
-
-static inline __be32
-tproxy_laddr4(struct sk_buff *skb, __be32 user_laddr, __be32 daddr)
-{
- struct in_device *indev;
- __be32 laddr;
-
- if (user_laddr)
- return user_laddr;
-
- laddr = 0;
- indev = __in_dev_get_rcu(skb->dev);
- for_primary_ifa(indev) {
- laddr = ifa->ifa_local;
- break;
- } endfor_ifa(indev);
-
- return laddr ? laddr : daddr;
-}
-
-/*
- * This is used when the user wants to intercept a connection matching
- * an explicit iptables rule. In this case the sockets are assumed
- * matching in preference order:
- *
- * - match: if there's a fully established connection matching the
- * _packet_ tuple, it is returned, assuming the redirection
- * already took place and we process a packet belonging to an
- * established connection
- *
- * - match: if there's a listening socket matching the redirection
- * (e.g. on-port & on-ip of the connection), it is returned,
- * regardless if it was bound to 0.0.0.0 or an explicit
- * address. The reasoning is that if there's an explicit rule, it
- * does not really matter if the listener is bound to an interface
- * or to 0. The user already stated that he wants redirection
- * (since he added the rule).
- *
- * Please note that there's an overlap between what a TPROXY target
- * and a socket match will match. Normally if you have both rules the
- * "socket" match will be the first one, effectively all packets
- * belonging to established connections going through that one.
- */
-static inline struct sock *
-nf_tproxy_get_sock_v4(struct net *net, struct sk_buff *skb, void *hp,
- const u8 protocol,
- const __be32 saddr, const __be32 daddr,
- const __be16 sport, const __be16 dport,
- const struct net_device *in,
- const enum nf_tproxy_lookup_t lookup_type)
-{
- struct sock *sk;
- struct tcphdr *tcph;
-
- switch (protocol) {
- case IPPROTO_TCP:
- switch (lookup_type) {
- case NFT_LOOKUP_LISTENER:
- tcph = hp;
- sk = inet_lookup_listener(net, &tcp_hashinfo, skb,
- ip_hdrlen(skb) +
- __tcp_hdrlen(tcph),
- saddr, sport,
- daddr, dport,
- in->ifindex, 0);
-
- if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
- sk = NULL;
- /* NOTE: we return listeners even if bound to
- * 0.0.0.0, those are filtered out in
- * xt_socket, since xt_TPROXY needs 0 bound
- * listeners too
- */
- break;
- case NFT_LOOKUP_ESTABLISHED:
- sk = inet_lookup_established(net, &tcp_hashinfo,
- saddr, sport, daddr, dport,
- in->ifindex);
- break;
- default:
- BUG();
- }
- break;
- case IPPROTO_UDP:
- sk = udp4_lib_lookup(net, saddr, sport, daddr, dport,
- in->ifindex);
- if (sk) {
- int connected = (sk->sk_state == TCP_ESTABLISHED);
- int wildcard = (inet_sk(sk)->inet_rcv_saddr == 0);
-
- /* NOTE: we return listeners even if bound to
- * 0.0.0.0, those are filtered out in
- * xt_socket, since xt_TPROXY needs 0 bound
- * listeners too
- */
- if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected || wildcard)) ||
- (lookup_type == NFT_LOOKUP_LISTENER && connected)) {
- sock_put(sk);
- sk = NULL;
- }
- }
- break;
- default:
- WARN_ON(1);
- sk = NULL;
- }
-
- pr_debug("tproxy socket lookup: proto %u %08x:%u -> %08x:%u, lookup type: %d, sock %p\n",
- protocol, ntohl(saddr), ntohs(sport), ntohl(daddr), ntohs(dport), lookup_type, sk);
-
- return sk;
-}
-
-#ifdef XT_TPROXY_HAVE_IPV6
-static inline struct sock *
-nf_tproxy_get_sock_v6(struct net *net, struct sk_buff *skb, int thoff, void *hp,
- const u8 protocol,
- const struct in6_addr *saddr, const struct in6_addr *daddr,
- const __be16 sport, const __be16 dport,
- const struct net_device *in,
- const enum nf_tproxy_lookup_t lookup_type)
-{
- struct sock *sk;
- struct tcphdr *tcph;
-
- switch (protocol) {
- case IPPROTO_TCP:
- switch (lookup_type) {
- case NFT_LOOKUP_LISTENER:
- tcph = hp;
- sk = inet6_lookup_listener(net, &tcp_hashinfo, skb,
- thoff + __tcp_hdrlen(tcph),
- saddr, sport,
- daddr, ntohs(dport),
- in->ifindex, 0);
-
- if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
- sk = NULL;
- /* NOTE: we return listeners even if bound to
- * 0.0.0.0, those are filtered out in
- * xt_socket, since xt_TPROXY needs 0 bound
- * listeners too
- */
- break;
- case NFT_LOOKUP_ESTABLISHED:
- sk = __inet6_lookup_established(net, &tcp_hashinfo,
- saddr, sport, daddr, ntohs(dport),
- in->ifindex, 0);
- break;
- default:
- BUG();
- }
- break;
- case IPPROTO_UDP:
- sk = udp6_lib_lookup(net, saddr, sport, daddr, dport,
- in->ifindex);
- if (sk) {
- int connected = (sk->sk_state == TCP_ESTABLISHED);
- int wildcard = ipv6_addr_any(&sk->sk_v6_rcv_saddr);
-
- /* NOTE: we return listeners even if bound to
- * 0.0.0.0, those are filtered out in
- * xt_socket, since xt_TPROXY needs 0 bound
- * listeners too
- */
- if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected || wildcard)) ||
- (lookup_type == NFT_LOOKUP_LISTENER && connected)) {
- sock_put(sk);
- sk = NULL;
- }
- }
- break;
- default:
- WARN_ON(1);
- sk = NULL;
- }
-
- pr_debug("tproxy socket lookup: proto %u %pI6:%u -> %pI6:%u, lookup type: %d, sock %p\n",
- protocol, saddr, ntohs(sport), daddr, ntohs(dport), lookup_type, sk);
-
- return sk;
-}
-#endif
-
-/**
- * tproxy_handle_time_wait4 - handle IPv4 TCP TIME_WAIT reopen redirections
- * @skb: The skb being processed.
- * @laddr: IPv4 address to redirect to or zero.
- * @lport: TCP port to redirect to or zero.
- * @sk: The TIME_WAIT TCP socket found by the lookup.
- *
- * We have to handle SYN packets arriving to TIME_WAIT sockets
- * differently: instead of reopening the connection we should rather
- * redirect the new connection to the proxy if there's a listener
- * socket present.
- *
- * tproxy_handle_time_wait4() consumes the socket reference passed in.
- *
- * Returns the listener socket if there's one, the TIME_WAIT socket if
- * no such listener is found, or NULL if the TCP header is incomplete.
- */
-static struct sock *
-tproxy_handle_time_wait4(struct net *net, struct sk_buff *skb,
- __be32 laddr, __be16 lport, struct sock *sk)
-{
- const struct iphdr *iph = ip_hdr(skb);
- struct tcphdr _hdr, *hp;
-
- hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
- if (hp == NULL) {
- inet_twsk_put(inet_twsk(sk));
- return NULL;
- }
-
- if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
- /* SYN to a TIME_WAIT socket, we'd rather redirect it
- * to a listener socket if there's one */
- struct sock *sk2;
-
- sk2 = nf_tproxy_get_sock_v4(net, skb, hp, iph->protocol,
- iph->saddr, laddr ? laddr : iph->daddr,
- hp->source, lport ? lport : hp->dest,
- skb->dev, NFT_LOOKUP_LISTENER);
- if (sk2) {
- inet_twsk_deschedule_put(inet_twsk(sk));
- sk = sk2;
- }
- }
-
- return sk;
-}
-
/* assign a socket to the skb -- consumes sk */
static void
nf_tproxy_assign_sock(struct sk_buff *skb, struct sock *sk)
@@ -308,26 +64,26 @@ tproxy_tg4(struct net *net, struct sk_buff *skb, __be32 laddr, __be16 lport,
sk = nf_tproxy_get_sock_v4(net, skb, hp, iph->protocol,
iph->saddr, iph->daddr,
hp->source, hp->dest,
- skb->dev, NFT_LOOKUP_ESTABLISHED);
+ skb->dev, NF_TPROXY_LOOKUP_ESTABLISHED);
- laddr = tproxy_laddr4(skb, laddr, iph->daddr);
+ laddr = nf_tproxy_laddr4(skb, laddr, iph->daddr);
if (!lport)
lport = 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 = tproxy_handle_time_wait4(net, skb, laddr, lport, sk);
+ sk = nf_tproxy_handle_time_wait4(net, skb, laddr, lport, 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(net, skb, hp, iph->protocol,
iph->saddr, laddr,
hp->source, lport,
- skb->dev, NFT_LOOKUP_LISTENER);
+ skb->dev, NF_TPROXY_LOOKUP_LISTENER);
/* NOTE: assign_sock consumes our sk reference */
- if (sk && tproxy_sk_is_transparent(sk)) {
+ if (sk && nf_tproxy_sk_is_transparent(sk)) {
/* This should be in a separate target, but we don't do multiple
targets on the same rule yet */
skb->mark = (skb->mark & ~mark_mask) ^ mark_value;
@@ -366,87 +122,6 @@ tproxy_tg4_v1(struct sk_buff *skb, const struct xt_action_param *par)
#ifdef XT_TPROXY_HAVE_IPV6
-static inline const struct in6_addr *
-tproxy_laddr6(struct sk_buff *skb, const struct in6_addr *user_laddr,
- const struct in6_addr *daddr)
-{
- struct inet6_dev *indev;
- struct inet6_ifaddr *ifa;
- struct in6_addr *laddr;
-
- if (!ipv6_addr_any(user_laddr))
- return user_laddr;
- laddr = NULL;
-
- indev = __in6_dev_get(skb->dev);
- if (indev) {
- read_lock_bh(&indev->lock);
- list_for_each_entry(ifa, &indev->addr_list, if_list) {
- if (ifa->flags & (IFA_F_TENTATIVE | IFA_F_DEPRECATED))
- continue;
-
- laddr = &ifa->addr;
- break;
- }
- read_unlock_bh(&indev->lock);
- }
-
- return laddr ? laddr : daddr;
-}
-
-/**
- * tproxy_handle_time_wait6 - handle IPv6 TCP TIME_WAIT reopen redirections
- * @skb: The skb being processed.
- * @tproto: Transport protocol.
- * @thoff: Transport protocol header offset.
- * @par: Iptables target parameters.
- * @sk: The TIME_WAIT TCP socket found by the lookup.
- *
- * We have to handle SYN packets arriving to TIME_WAIT sockets
- * differently: instead of reopening the connection we should rather
- * redirect the new connection to the proxy if there's a listener
- * socket present.
- *
- * tproxy_handle_time_wait6() consumes the socket reference passed in.
- *
- * Returns the listener socket if there's one, the TIME_WAIT socket if
- * no such listener is found, or NULL if the TCP header is incomplete.
- */
-static struct sock *
-tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff,
- const struct xt_action_param *par,
- struct sock *sk)
-{
- const struct ipv6hdr *iph = ipv6_hdr(skb);
- struct tcphdr _hdr, *hp;
- const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
-
- hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
- if (hp == NULL) {
- inet_twsk_put(inet_twsk(sk));
- return NULL;
- }
-
- if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
- /* SYN to a TIME_WAIT socket, we'd rather redirect it
- * to a listener socket if there's one */
- struct sock *sk2;
-
- sk2 = nf_tproxy_get_sock_v6(xt_net(par), skb, thoff, hp, tproto,
- &iph->saddr,
- tproxy_laddr6(skb, &tgi->laddr.in6, &iph->daddr),
- hp->source,
- tgi->lport ? tgi->lport : hp->dest,
- skb->dev, NFT_LOOKUP_LISTENER);
- if (sk2) {
- inet_twsk_deschedule_put(inet_twsk(sk));
- sk = sk2;
- }
- }
-
- return sk;
-}
-
static unsigned int
tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
{
@@ -478,25 +153,31 @@ tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
sk = nf_tproxy_get_sock_v6(xt_net(par), skb, thoff, hp, tproto,
&iph->saddr, &iph->daddr,
hp->source, hp->dest,
- xt_in(par), NFT_LOOKUP_ESTABLISHED);
+ xt_in(par), NF_TPROXY_LOOKUP_ESTABLISHED);
- laddr = tproxy_laddr6(skb, &tgi->laddr.in6, &iph->daddr);
+ laddr = nf_tproxy_laddr6(skb, &tgi->laddr.in6, &iph->daddr);
lport = tgi->lport ? tgi->lport : hp->dest;
/* UDP has no TCP_TIME_WAIT state, so we never enter here */
- if (sk && sk->sk_state == TCP_TIME_WAIT)
+ if (sk && sk->sk_state == TCP_TIME_WAIT) {
+ const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
/* reopening a TIME_WAIT connection needs special handling */
- sk = tproxy_handle_time_wait6(skb, tproto, thoff, par, sk);
+ sk = nf_tproxy_handle_time_wait6(skb, tproto, thoff,
+ xt_net(par),
+ &tgi->laddr.in6,
+ tgi->lport,
+ 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(xt_net(par), skb, thoff, hp,
tproto, &iph->saddr, laddr,
hp->source, lport,
- xt_in(par), NFT_LOOKUP_LISTENER);
+ xt_in(par), NF_TPROXY_LOOKUP_LISTENER);
/* NOTE: assign_sock consumes our sk reference */
- if (sk && tproxy_sk_is_transparent(sk)) {
+ if (sk && nf_tproxy_sk_is_transparent(sk)) {
/* This should be in a separate target, but we don't do multiple
targets on the same rule yet */
skb->mark = (skb->mark & ~tgi->mark_mask) ^ tgi->mark_value;
The extracted functions will likely be usefull to implement tproxy support in nf_tables. Extrancted functions: - nf_tproxy_sk_is_transparent - nf_tproxy_laddr4 - nf_tproxy_handle_time_wait4 - nf_tproxy_get_sock_v4 - nf_tproxy_laddr6 - nf_tproxy_handle_time_wait6 - nf_tproxy_get_sock_v6 (nf_)tproxy_handle_time_wait6 also needed some refactor as its current implementation was xtables-specific. Signed-off-by: Máté Eckl <ecklm94@gmail.com> --- include/net/netfilter/nf_tproxy.h | 113 +++++++++ net/ipv4/netfilter/Kconfig | 8 +- net/ipv4/netfilter/Makefile | 1 + net/ipv4/netfilter/nf_tproxy_ipv4.c | 147 ++++++++++++ net/ipv6/netfilter/Kconfig | 8 +- net/ipv6/netfilter/Makefile | 1 + net/ipv6/netfilter/nf_tproxy_ipv6.c | 146 ++++++++++++ net/netfilter/Kconfig | 2 + net/netfilter/xt_TPROXY.c | 355 ++-------------------------- 9 files changed, 442 insertions(+), 339 deletions(-) create mode 100644 include/net/netfilter/nf_tproxy.h create mode 100644 net/ipv4/netfilter/nf_tproxy_ipv4.c create mode 100644 net/ipv6/netfilter/nf_tproxy_ipv6.c