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

• Lines: 119
• Date: Thu Nov 28 15:53:15 2002
• Orig file: linux-2.4.19/net/ipv4/netfilter/ipt_ecn.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/net/ipv4/netfilter/ipt_ecn.c linux-2.4.20/net/ipv4/netfilter/ipt_ecn.c
@@ -0,0 +1,118 @@
+/* IP tables module for matching the value of the IPv4 and TCP ECN bits
+ *
+ * ipt_ecn.c,v 1.3 2002/05/29 15:09:00 laforge Exp
+ *
+ * (C) 2002 by Harald Welte <laforge@gnumonks.org>
+ *
+ * This software is distributed under the terms GNU GPL v2
+ */
+
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/tcp.h>
+
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv4/ipt_ecn.h>
+
+MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
+MODULE_DESCRIPTION("IP tables ECN matching module");
+MODULE_LICENSE("GPL");
+
+static inline int match_ip(const struct sk_buff *skb,
+			   const struct iphdr *iph,
+			   const struct ipt_ecn_info *einfo)
+{
+	return ((iph->tos&IPT_ECN_IP_MASK) == einfo->ip_ect);
+}
+
+static inline int match_tcp(const struct sk_buff *skb,
+			    const struct iphdr *iph,
+			    const struct ipt_ecn_info *einfo)
+{
+	struct tcphdr *tcph = (void *)iph + iph->ihl*4;
+
+	if (einfo->operation & IPT_ECN_OP_MATCH_ECE) {
+		if (einfo->invert & IPT_ECN_OP_MATCH_ECE) {
+			if (tcph->ece == 1)
+				return 0;
+		} else {
+			if (tcph->ece == 0)
+				return 0;
+		}
+	}
+
+	if (einfo->operation & IPT_ECN_OP_MATCH_CWR) {
+		if (einfo->invert & IPT_ECN_OP_MATCH_CWR) {
+			if (tcph->cwr == 1)
+				return 0;
+		} else {
+			if (tcph->cwr == 0)
+				return 0;
+		}
+	}
+
+	return 1;
+}
+
+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_ecn_info *info = matchinfo;
+	const struct iphdr *iph = skb->nh.iph;
+
+	if (info->operation & IPT_ECN_OP_MATCH_IP)
+		if (!match_ip(skb, iph, info))
+			return 0;
+
+	if (info->operation & (IPT_ECN_OP_MATCH_ECE|IPT_ECN_OP_MATCH_CWR)) {
+		if (iph->protocol != IPPROTO_TCP)
+			return 0;
+		if (!match_tcp(skb, iph, info))
+			return 0;
+	}
+
+	return 1;
+}
+
+static int checkentry(const char *tablename, const struct ipt_ip *ip,
+		      void *matchinfo, unsigned int matchsize,
+		      unsigned int hook_mask)
+{
+	const struct ipt_ecn_info *info = matchinfo;
+
+	if (matchsize != IPT_ALIGN(sizeof(struct ipt_ecn_info)))
+		return 0;
+
+	if (info->operation & IPT_ECN_OP_MATCH_MASK)
+		return 0;
+
+	if (info->invert & IPT_ECN_OP_MATCH_MASK)
+		return 0;
+
+	if (info->operation & (IPT_ECN_OP_MATCH_ECE|IPT_ECN_OP_MATCH_CWR)
+	    && ip->proto != IPPROTO_TCP) {
+		printk(KERN_WARNING "ipt_ecn: can't match TCP bits in rule for"
+		       " non-tcp packets\n");
+		return 0;
+	}
+
+	return 1;
+}
+
+static struct ipt_match ecn_match = { { NULL, NULL }, "ecn", &match,
+		&checkentry, NULL, THIS_MODULE };
+
+static int __init init(void)
+{
+	return ipt_register_match(&ecn_match);
+}
+
+static void __exit fini(void)
+{
+	ipt_unregister_match(&ecn_match);
+}
+
+module_init(init);
+module_exit(fini);