patch-2.4.20 linux-2.4.20/net/ipv4/netfilter/ipt_conntrack.c

• Lines: 124
• Date: Thu Nov 28 15:53:15 2002
• Orig file: linux-2.4.19/net/ipv4/netfilter/ipt_conntrack.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/net/ipv4/netfilter/ipt_conntrack.c linux-2.4.20/net/ipv4/netfilter/ipt_conntrack.c
@@ -0,0 +1,123 @@
+/* Kernel module to match connection tracking information.
+ * Superset of Rusty's minimalistic state match.
+ * GPL (C) 2001  Marc Boucher (marc@mbsi.ca).
+ */
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/netfilter_ipv4/ip_conntrack.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv4/ipt_conntrack.h>
+
+static int
+match(const struct sk_buff *skb,
+      const struct net_device *in,
+      const struct net_device *out,
+      const void *matchinfo,
+      int offset,
+      const void *hdr,
+      u_int16_t datalen,
+      int *hotdrop)
+{
+	const struct ipt_conntrack_info *sinfo = matchinfo;
+	struct ip_conntrack *ct;
+	enum ip_conntrack_info ctinfo;
+	unsigned int statebit;
+
+	ct = ip_conntrack_get((struct sk_buff *)skb, &ctinfo);
+
+#define FWINV(bool,invflg) ((bool) ^ !!(sinfo->invflags & invflg))
+
+	statebit = ct ? IPT_CONNTRACK_STATE_INVALID : IPT_CONNTRACK_STATE_BIT(ctinfo);
+	if(sinfo->flags & IPT_CONNTRACK_STATE) {
+		if (ct) {
+			if(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip !=
+			    ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip)
+				statebit |= IPT_CONNTRACK_STATE_SNAT;
+
+			if(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip !=
+			    ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip)
+				statebit |= IPT_CONNTRACK_STATE_DNAT;
+		}
+
+		if (FWINV((statebit & sinfo->statemask) == 0, IPT_CONNTRACK_STATE))
+			return 0;
+	}
+
+	if(sinfo->flags & IPT_CONNTRACK_PROTO) {
+		if (!ct || FWINV(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum != sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.protonum, IPT_CONNTRACK_PROTO))
+                	return 0;
+	}
+
+	if(sinfo->flags & IPT_CONNTRACK_ORIGSRC) {
+		if (!ct || FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip&sinfo->sipmsk[IP_CT_DIR_ORIGINAL].s_addr) != sinfo->tuple[IP_CT_DIR_ORIGINAL].src.ip, IPT_CONNTRACK_ORIGSRC))
+			return 0;
+	}
+
+	if(sinfo->flags & IPT_CONNTRACK_ORIGDST) {
+		if (!ct || FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip&sinfo->dipmsk[IP_CT_DIR_ORIGINAL].s_addr) != sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.ip, IPT_CONNTRACK_ORIGDST))
+			return 0;
+	}
+
+	if(sinfo->flags & IPT_CONNTRACK_REPLSRC) {
+		if (!ct || FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip&sinfo->sipmsk[IP_CT_DIR_REPLY].s_addr) != sinfo->tuple[IP_CT_DIR_REPLY].src.ip, IPT_CONNTRACK_REPLSRC))
+			return 0;
+	}
+
+	if(sinfo->flags & IPT_CONNTRACK_REPLDST) {
+		if (!ct || FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip&sinfo->dipmsk[IP_CT_DIR_REPLY].s_addr) != sinfo->tuple[IP_CT_DIR_REPLY].dst.ip, IPT_CONNTRACK_REPLDST))
+			return 0;
+	}
+
+	if(sinfo->flags & IPT_CONNTRACK_STATUS) {
+		if (!ct || FWINV((ct->status & sinfo->statusmask) == 0, IPT_CONNTRACK_STATUS))
+			return 0;
+	}
+
+	if(sinfo->flags & IPT_CONNTRACK_EXPIRES) {
+		unsigned long expires;
+
+		if(!ct)
+			return 0;
+
+		expires = timer_pending(&ct->timeout) ? (ct->timeout.expires - jiffies)/HZ : 0;
+
+		if (FWINV(!(expires >= sinfo->expires_min && expires <= sinfo->expires_max), IPT_CONNTRACK_EXPIRES))
+			return 0;
+	}
+
+	return 1;
+}
+
+static int check(const char *tablename,
+		 const struct ipt_ip *ip,
+		 void *matchinfo,
+		 unsigned int matchsize,
+		 unsigned int hook_mask)
+{
+	if (matchsize != IPT_ALIGN(sizeof(struct ipt_conntrack_info)))
+		return 0;
+
+	return 1;
+}
+
+static struct ipt_match conntrack_match
+= { { NULL, NULL }, "conntrack", &match, &check, NULL, THIS_MODULE };
+
+static int __init init(void)
+{
+	/* NULL if ip_conntrack not a module */
+	if (ip_conntrack_module)
+		__MOD_INC_USE_COUNT(ip_conntrack_module);
+	return ipt_register_match(&conntrack_match);
+}
+
+static void __exit fini(void)
+{
+	ipt_unregister_match(&conntrack_match);
+	if (ip_conntrack_module)
+		__MOD_DEC_USE_COUNT(ip_conntrack_module);
+}
+
+module_init(init);
+module_exit(fini);
+MODULE_LICENSE("GPL");