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authorMáté Eckl <ecklm94@gmail.com>2018-06-01 21:44:56 +0300
committerPablo Neira Ayuso <pablo@netfilter.org>2018-06-03 01:02:05 +0300
commit45ca4e0cf2734f8cc14b43e47c23618215abf1b8 (patch)
tree5772c57c59d7d30743a4175ff6dc15c1d2234526 /net/ipv6
parent8d6e555773690e6fdefd99723fcd0a7e432c0c90 (diff)
downloadlinux-45ca4e0cf2734f8cc14b43e47c23618215abf1b8.tar.xz
netfilter: Libify xt_TPROXY
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> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/netfilter/Kconfig5
-rw-r--r--net/ipv6/netfilter/Makefile1
-rw-r--r--net/ipv6/netfilter/nf_tproxy_ipv6.c146
3 files changed, 151 insertions, 1 deletions
diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig
index 9f5b00a39adf..37b14dc9d863 100644
--- a/net/ipv6/netfilter/Kconfig
+++ b/net/ipv6/netfilter/Kconfig
@@ -29,7 +29,10 @@ 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"
if NF_TABLES
diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile
index 71518f22ae39..10a5a1c87320 100644
--- a/net/ipv6/netfilter/Makefile
+++ b/net/ipv6/netfilter/Makefile
@@ -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
diff --git a/net/ipv6/netfilter/nf_tproxy_ipv6.c b/net/ipv6/netfilter/nf_tproxy_ipv6.c
new file mode 100644
index 000000000000..bf1d6c421e3b
--- /dev/null
+++ b/net/ipv6/netfilter/nf_tproxy_ipv6.c
@@ -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");