This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / net / ipv6 / netfilter / ip6t_HL.c

diff --git a/net/ipv6/netfilter/ip6t_HL.c b/net/ipv6/netfilter/ip6t_HL.c
new file mode 100644 (file)
index 0000000..b8eff8e
--- /dev/null
+++ b/net/ipv6/netfilter/ip6t_HL.c
@@ -0,0 +1,107 @@
+/* 
+ * Hop Limit modification target for ip6tables
+ * Maciej Soltysiak <solt@dns.toxicfilms.tv>
+ * Based on HW's TTL module
+ *
+ * This software is distributed under the terms of GNU GPL
+ */
+
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/ip.h>
+
+#include <linux/netfilter_ipv6/ip6_tables.h>
+#include <linux/netfilter_ipv6/ip6t_HL.h>
+
+MODULE_AUTHOR("Maciej Soltysiak <solt@dns.toxicfilms.tv>");
+MODULE_DESCRIPTION("IP tables Hop Limit modification module");
+MODULE_LICENSE("GPL");
+
+static unsigned int ip6t_hl_target(struct sk_buff **pskb, 
+                                  const struct net_device *in,
+                                  const struct net_device *out,
+                                  unsigned int hooknum,
+                                  const struct xt_target *target,
+                                  const void *targinfo, void *userinfo)
+{
+       struct ipv6hdr *ip6h;
+       const struct ip6t_HL_info *info = targinfo;
+       u_int16_t diffs[2];
+       int new_hl;
+
+       if (!skb_make_writable(pskb, (*pskb)->len))
+               return NF_DROP;
+
+       ip6h = (*pskb)->nh.ipv6h;
+
+       switch (info->mode) {
+               case IP6T_HL_SET:
+                       new_hl = info->hop_limit;
+                       break;
+               case IP6T_HL_INC:
+                       new_hl = ip6h->hop_limit + info->hop_limit;
+                       if (new_hl > 255)
+                               new_hl = 255;
+                       break;
+               case IP6T_HL_DEC:
+                       new_hl = ip6h->hop_limit - info->hop_limit;
+                       if (new_hl < 0)
+                               new_hl = 0;
+                       break;
+               default:
+                       new_hl = ip6h->hop_limit;
+                       break;
+       }
+
+       if (new_hl != ip6h->hop_limit) {
+               diffs[0] = htons(((unsigned)ip6h->hop_limit) << 8) ^ 0xFFFF;
+               ip6h->hop_limit = new_hl;
+               diffs[1] = htons(((unsigned)ip6h->hop_limit) << 8);
+       }
+
+       return IP6T_CONTINUE;
+}
+
+static int ip6t_hl_checkentry(const char *tablename,
+               const void *entry,
+               const struct xt_target *target,
+               void *targinfo,
+               unsigned int targinfosize,
+               unsigned int hook_mask)
+{
+       struct ip6t_HL_info *info = targinfo;
+
+       if (info->mode > IP6T_HL_MAXMODE) {
+               printk(KERN_WARNING "ip6t_HL: invalid or unknown Mode %u\n", 
+                       info->mode);
+               return 0;
+       }
+       if ((info->mode != IP6T_HL_SET) && (info->hop_limit == 0)) {
+               printk(KERN_WARNING "ip6t_HL: increment/decrement doesn't "
+                       "make sense with value 0\n");
+               return 0;
+       }
+       return 1;
+}
+
+static struct ip6t_target ip6t_HL = { 
+       .name           = "HL", 
+       .target         = ip6t_hl_target, 
+       .targetsize     = sizeof(struct ip6t_HL_info),
+       .table          = "mangle",
+       .checkentry     = ip6t_hl_checkentry, 
+       .me             = THIS_MODULE
+};
+
+static int __init ip6t_hl_init(void)
+{
+       return ip6t_register_target(&ip6t_HL);
+}
+
+static void __exit ip6t_hl_fini(void)
+{
+       ip6t_unregister_target(&ip6t_HL);
+}
+
+module_init(ip6t_hl_init);
+module_exit(ip6t_hl_fini);