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Diffstat (limited to 'net/ipv4/netfilter/ipt_ecn.c')
-rw-r--r--net/ipv4/netfilter/ipt_ecn.c131
1 files changed, 131 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ipt_ecn.c b/net/ipv4/netfilter/ipt_ecn.c
new file mode 100644
index 00000000000..b6f7181e89c
--- /dev/null
+++ b/net/ipv4/netfilter/ipt_ecn.c
@@ -0,0 +1,131 @@
+/* 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 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 <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@netfilter.org>");
+MODULE_DESCRIPTION("iptables ECN matching module");
+MODULE_LICENSE("GPL");
+
+static inline int match_ip(const struct sk_buff *skb,
+ const struct ipt_ecn_info *einfo)
+{
+ return ((skb->nh.iph->tos&IPT_ECN_IP_MASK) == einfo->ip_ect);
+}
+
+static inline int match_tcp(const struct sk_buff *skb,
+ const struct ipt_ecn_info *einfo,
+ int *hotdrop)
+{
+ struct tcphdr _tcph, *th;
+
+ /* In practice, TCP match does this, so can't fail. But let's
+ * be good citizens.
+ */
+ th = skb_header_pointer(skb, skb->nh.iph->ihl * 4,
+ sizeof(_tcph), &_tcph);
+ if (th == NULL) {
+ *hotdrop = 0;
+ return 0;
+ }
+
+ if (einfo->operation & IPT_ECN_OP_MATCH_ECE) {
+ if (einfo->invert & IPT_ECN_OP_MATCH_ECE) {
+ if (th->ece == 1)
+ return 0;
+ } else {
+ if (th->ece == 0)
+ return 0;
+ }
+ }
+
+ if (einfo->operation & IPT_ECN_OP_MATCH_CWR) {
+ if (einfo->invert & IPT_ECN_OP_MATCH_CWR) {
+ if (th->cwr == 1)
+ return 0;
+ } else {
+ if (th->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, int *hotdrop)
+{
+ const struct ipt_ecn_info *info = matchinfo;
+
+ if (info->operation & IPT_ECN_OP_MATCH_IP)
+ if (!match_ip(skb, info))
+ return 0;
+
+ if (info->operation & (IPT_ECN_OP_MATCH_ECE|IPT_ECN_OP_MATCH_CWR)) {
+ if (skb->nh.iph->protocol != IPPROTO_TCP)
+ return 0;
+ if (!match_tcp(skb, info, hotdrop))
+ 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 = {
+ .name = "ecn",
+ .match = &match,
+ .checkentry = &checkentry,
+ .me = 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);