From: Hannes Eder <hannes@xxxxxxxxxxxxxx>
This implements the kernel-space side of the iptables matcher xt_ipvs.
Signed-off-by: Hannes Eder <heder@xxxxxxxxxx>
include/linux/netfilter/xt_ipvs.h | 32 +++++++
net/netfilter/Kconfig | 8 ++
net/netfilter/Makefile | 1
net/netfilter/ipvs/ip_vs_proto.c | 1
net/netfilter/xt_ipvs.c | 171 +++++++++++++++++++++++++++++++++++++
5 files changed, 213 insertions(+), 0 deletions(-)
create mode 100644 include/linux/netfilter/xt_ipvs.h
create mode 100644 net/netfilter/xt_ipvs.c
diff --git a/include/linux/netfilter/xt_ipvs.h b/include/linux/netfilter/xt_ipvs.h
new file mode 100644
index 0000000..3a70289
--- /dev/null
+++ b/include/linux/netfilter/xt_ipvs.h
@@ -0,0 +1,32 @@
+#ifndef _XT_IPVS_H
+#define _XT_IPVS_H 1
+
+#ifndef _IP_VS_H
+#define IP_VS_CONN_F_FWD_MASK 0x0007 /* mask for the fwd methods */
+#define IP_VS_CONN_F_MASQ 0x0000 /* masquerading/NAT */
+#define IP_VS_CONN_F_LOCALNODE 0x0001 /* local node */
+#define IP_VS_CONN_F_TUNNEL 0x0002 /* tunneling */
+#define IP_VS_CONN_F_DROUTE 0x0003 /* direct routing */
+#define IP_VS_CONN_F_BYPASS 0x0004 /* cache bypass */
+#endif
+
+#define XT_IPVS_IPVS 0x01 /* this is implied by all other options */
+#define XT_IPVS_PROTO 0x02
+#define XT_IPVS_VADDR 0x04
+#define XT_IPVS_VPORT 0x08
+#define XT_IPVS_DIR 0x10
+#define XT_IPVS_METHOD 0x20
+#define XT_IPVS_MASK (0x40 - 1)
+#define XT_IPVS_ONCE_MASK (XT_IPVS_MASK & ~XT_IPVS_IPVS)
+
+struct xt_ipvs {
+ union nf_inet_addr vaddr, vmask;
+ __be16 vport;
+ u_int16_t l4proto;
+ u_int16_t fwd_method;
+
+ u_int8_t invert;
+ u_int8_t bitmask;
+};
+
+#endif /* _XT_IPVS_H */
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index cb3ad74..677a880 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -678,6 +678,14 @@ config NETFILTER_XT_MATCH_IPRANGE
If unsure, say M.
+config NETFILTER_XT_MATCH_IPVS
+ tristate '"ipvs" match support'
+ depends on NETFILTER_ADVANCED
+ help
+ This option allows you to match against ipvs properties of a packet.
+
+ To compile it as a module, choos M here. If unsure, say N.
+
config NETFILTER_XT_MATCH_LENGTH
tristate '"length" match support'
depends on NETFILTER_ADVANCED
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 6282060..1c18e80 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -72,6 +72,7 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_HASHLIMIT) += xt_hashlimit.o
obj-$(CONFIG_NETFILTER_XT_MATCH_HELPER) += xt_helper.o
obj-$(CONFIG_NETFILTER_XT_MATCH_HL) += xt_hl.o
obj-$(CONFIG_NETFILTER_XT_MATCH_IPRANGE) += xt_iprange.o
+obj-$(CONFIG_NETFILTER_XT_MATCH_IPVS) += xt_ipvs.o
obj-$(CONFIG_NETFILTER_XT_MATCH_LENGTH) += xt_length.o
obj-$(CONFIG_NETFILTER_XT_MATCH_LIMIT) += xt_limit.o
obj-$(CONFIG_NETFILTER_XT_MATCH_MAC) += xt_mac.o
diff --git a/net/netfilter/ipvs/ip_vs_proto.c b/net/netfilter/ipvs/ip_vs_proto.c
index a01520e..84bf4e6 100644
--- a/net/netfilter/ipvs/ip_vs_proto.c
+++ b/net/netfilter/ipvs/ip_vs_proto.c
@@ -94,6 +94,7 @@ struct ip_vs_protocol * ip_vs_proto_get(unsigned short proto)
return NULL;
}
+EXPORT_SYMBOL(ip_vs_proto_get);
/*
diff --git a/net/netfilter/xt_ipvs.c b/net/netfilter/xt_ipvs.c
new file mode 100644
index 0000000..00373d9
--- /dev/null
+++ b/net/netfilter/xt_ipvs.c
@@ -0,0 +1,171 @@
+/*
+ * xt_ipvs - kernel module to match ipvs properties of a packet
+ *
+ * Author: Hannes Eder <heder@xxxxxxxxxx>
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/spinlock.h>
+#include <linux/skbuff.h>
+#ifdef CONFIG_IP_VS_IPV6
+#include <net/ipv6.h>
+#endif
+#include <linux/types.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_ipvs.h>
+
+#include <net/ip_vs.h>
+
+MODULE_AUTHOR("Hannes Eder <heder@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Xtables: match ipvs");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ipt_ipvs");
+MODULE_ALIAS("ip6t_ipvs");
+
+/* borrowed from xt_conntrack */
+static bool ipvs_mt_addrcmp(const union nf_inet_addr *kaddr,
+ const union nf_inet_addr *uaddr,
+ const union nf_inet_addr *umask,
+ unsigned int l3proto)
+{
+ if (l3proto == NFPROTO_IPV4)
+ return ((kaddr->ip ^ uaddr->ip) & umask->ip) == 0;
+#ifdef CONFIG_IP_VS_IPV6
+ else if (l3proto == NFPROTO_IPV6)
+ return ipv6_masked_addr_cmp(&kaddr->in6, &umask->in6,
+ &uaddr->in6) == 0;
+#endif
+ else
+ return false;
+}
+
+bool ipvs_mt(const struct sk_buff *skb, const struct xt_match_param *par)
+{
+ const struct xt_ipvs *data = par->matchinfo;
+ const u_int8_t family = par->family;
+ struct ip_vs_iphdr iph;
+ struct ip_vs_protocol *pp;
+ struct ip_vs_conn *cp;
+ int af;
+ bool match = true;
+
+ if (data->bitmask == XT_IPVS_IPVS) {
+ match = !!(skb->ipvs_property)
+ ^ !!(data->invert & XT_IPVS_IPVS);
+ goto out;
+ }
+
+ /* other flags than XT_IPVS_IPVS are set */
+ if (!skb->ipvs_property) {
+ match = false;
+ goto out;
+ }
+
+ switch (skb->protocol) {
+ case htons(ETH_P_IP):
+ af = AF_INET;
+ break;
+#ifdef CONFIG_IP_VS_IPV6
+ case htons(ETH_P_IPV6):
+ af = AF_INET6;
+ break;
+#endif
+ default:
+ match = false;
+ goto out;
+ }
+
+ ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
+
+ if (data->bitmask & XT_IPVS_PROTO)
+ if ((iph.protocol == data->l4proto)
+ ^ !(data->invert & XT_IPVS_PROTO)) {
+ match = false;
+ goto out;
+ }
+
+ pp = ip_vs_proto_get(iph.protocol);
+ if (unlikely(!pp)) {
+ match = false;
+ goto out;
+ }
+
+ /*
+ * Check if the packet belongs to an existing entry
+ */
+ /* TODO: why does it only match in inverse? */
+ cp = pp->conn_out_get(af, skb, pp, &iph, iph.len, 1 /* inverse */);
+ if (unlikely(!cp)) {
+ match = false;
+ goto out;
+ }
+
+ /*
+ * We found a connection, i.e. ct != 0, make sure to call
+ * __ip_vs_conn_put before returning. In our case jump to out_put_con.
+ */
+
+ if (data->bitmask & XT_IPVS_VPORT)
+ if ((cp->vport == data->vport)
+ ^ !(data->invert & XT_IPVS_VPORT)) {
+ match = false;
+ goto out_put_ct;
+ }
+
+ if (data->bitmask & XT_IPVS_DIR) {
+ /* TODO: implement */
+ }
+
+ if (data->bitmask & XT_IPVS_METHOD)
+ if (((cp->flags & IP_VS_CONN_F_FWD_MASK) == data->fwd_method)
+ ^ !(data->invert & XT_IPVS_METHOD)) {
+ match = false;
+ goto out_put_ct;
+ }
+
+ if (data->bitmask & XT_IPVS_VADDR) {
+ if (af != family) {
+ match = false;
+ goto out_put_ct;
+ }
+
+ if (ipvs_mt_addrcmp(&cp->vaddr, &data->vaddr, &data->vmask, af)
+ ^ !(data->invert & XT_IPVS_VADDR)) {
+ match = false;
+ goto out_put_ct;
+ }
+ }
+
+out_put_ct:
+ __ip_vs_conn_put(cp);
+out:
+ return match;
+}
+EXPORT_SYMBOL(ipvs_mt);
+
+static struct xt_match xt_ipvs_mt_reg[] __read_mostly = {
+ {
+ .name = "ipvs",
+ .revision = 0,
+ .family = NFPROTO_UNSPEC,
+ .match = ipvs_mt,
+ .matchsize = sizeof(struct xt_ipvs),
+ .me = THIS_MODULE,
+ },
+};
+
+static int __init ipvs_mt_init(void)
+{
+ return xt_register_matches(xt_ipvs_mt_reg,
+ ARRAY_SIZE(xt_ipvs_mt_reg));
+}
+
+static void __exit ipvs_mt_exit(void)
+{
+ xt_unregister_matches(xt_ipvs_mt_reg,
+ ARRAY_SIZE(xt_ipvs_mt_reg));
+}
+
+module_init(ipvs_mt_init);
+module_exit(ipvs_mt_exit);
--
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