patch-2.4.14 linux/net/ipv4/netfilter/ipt_length.c
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- Lines: 56
- Date:
Tue Oct 30 15:08:12 2001
- Orig file:
v2.4.13/linux/net/ipv4/netfilter/ipt_length.c
- Orig date:
Wed Dec 31 16:00:00 1969
diff -u --recursive --new-file v2.4.13/linux/net/ipv4/netfilter/ipt_length.c linux/net/ipv4/netfilter/ipt_length.c
@@ -0,0 +1,55 @@
+/* Kernel module to match packet length. */
+#include <linux/module.h>
+#include <linux/skbuff.h>
+
+#include <linux/netfilter_ipv4/ipt_length.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+
+MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
+MODULE_DESCRIPTION("IP tables packet length matching module");
+MODULE_LICENSE("GPL");
+
+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_length_info *info = matchinfo;
+ u_int16_t pktlen = ntohs(skb->nh.iph->tot_len);
+
+ return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;
+}
+
+static int
+checkentry(const char *tablename,
+ const struct ipt_ip *ip,
+ void *matchinfo,
+ unsigned int matchsize,
+ unsigned int hook_mask)
+{
+ if (matchsize != IPT_ALIGN(sizeof(struct ipt_length_info)))
+ return 0;
+
+ return 1;
+}
+
+static struct ipt_match length_match
+= { { NULL, NULL }, "length", &match, &checkentry, NULL, THIS_MODULE };
+
+static int __init init(void)
+{
+ return ipt_register_match(&length_match);
+}
+
+static void __exit fini(void)
+{
+ ipt_unregister_match(&length_match);
+}
+
+module_init(init);
+module_exit(fini);
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