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authorJan Engelhardt <jengelh@medozas.de>2009-02-18 18:38:40 +0100
committerPatrick McHardy <kaber@trash.net>2009-02-18 18:38:40 +0100
commit563d36eb3fb22dd04da9aa6f12e1b9ba0ac115f3 (patch)
tree9ff10949c9382b98756fa8da6ded257f00249b84 /net/netfilter/xt_HL.c
parentddc214c43a923e89741e04da2f10e3037a64e222 (diff)
netfilter: Combine ipt_TTL and ip6t_HL source
Suggested by: James King <t.james.king@gmail.com> Similarly to commit c9fd49680954714473d6cbd2546d6ff120f96840, merge TTL and HL. Since HL does not depend on any IPv6-specific function, no new module dependencies would arise. With slight adjustments to the Kconfig help text. Signed-off-by: Jan Engelhardt <jengelh@medozas.de> Signed-off-by: Patrick McHardy <kaber@trash.net>
Diffstat (limited to 'net/netfilter/xt_HL.c')
-rw-r--r--net/netfilter/xt_HL.c171
1 files changed, 171 insertions, 0 deletions
diff --git a/net/netfilter/xt_HL.c b/net/netfilter/xt_HL.c
new file mode 100644
index 00000000000..10e789e2d12
--- /dev/null
+++ b/net/netfilter/xt_HL.c
@@ -0,0 +1,171 @@
+/*
+ * TTL modification target for IP tables
+ * (C) 2000,2005 by Harald Welte <laforge@netfilter.org>
+ *
+ * Hop Limit modification target for ip6tables
+ * Maciej Soltysiak <solt@dns.toxicfilms.tv>
+ *
+ * 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/ip.h>
+#include <linux/ipv6.h>
+#include <net/checksum.h>
+
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter_ipv4/ipt_TTL.h>
+#include <linux/netfilter_ipv6/ip6t_HL.h>
+
+MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
+MODULE_AUTHOR("Maciej Soltysiak <solt@dns.toxicfilms.tv>");
+MODULE_DESCRIPTION("Xtables: Hoplimit/TTL Limit field modification target");
+MODULE_LICENSE("GPL");
+
+static unsigned int
+ttl_tg(struct sk_buff *skb, const struct xt_target_param *par)
+{
+ struct iphdr *iph;
+ const struct ipt_TTL_info *info = par->targinfo;
+ int new_ttl;
+
+ if (!skb_make_writable(skb, skb->len))
+ return NF_DROP;
+
+ iph = ip_hdr(skb);
+
+ switch (info->mode) {
+ case IPT_TTL_SET:
+ new_ttl = info->ttl;
+ break;
+ case IPT_TTL_INC:
+ new_ttl = iph->ttl + info->ttl;
+ if (new_ttl > 255)
+ new_ttl = 255;
+ break;
+ case IPT_TTL_DEC:
+ new_ttl = iph->ttl - info->ttl;
+ if (new_ttl < 0)
+ new_ttl = 0;
+ break;
+ default:
+ new_ttl = iph->ttl;
+ break;
+ }
+
+ if (new_ttl != iph->ttl) {
+ csum_replace2(&iph->check, htons(iph->ttl << 8),
+ htons(new_ttl << 8));
+ iph->ttl = new_ttl;
+ }
+
+ return XT_CONTINUE;
+}
+
+static unsigned int
+hl_tg6(struct sk_buff *skb, const struct xt_target_param *par)
+{
+ struct ipv6hdr *ip6h;
+ const struct ip6t_HL_info *info = par->targinfo;
+ int new_hl;
+
+ if (!skb_make_writable(skb, skb->len))
+ return NF_DROP;
+
+ ip6h = ipv6_hdr(skb);
+
+ 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;
+ }
+
+ ip6h->hop_limit = new_hl;
+
+ return XT_CONTINUE;
+}
+
+static bool ttl_tg_check(const struct xt_tgchk_param *par)
+{
+ const struct ipt_TTL_info *info = par->targinfo;
+
+ if (info->mode > IPT_TTL_MAXMODE) {
+ printk(KERN_WARNING "ipt_TTL: invalid or unknown Mode %u\n",
+ info->mode);
+ return false;
+ }
+ if (info->mode != IPT_TTL_SET && info->ttl == 0)
+ return false;
+ return true;
+}
+
+static bool hl_tg6_check(const struct xt_tgchk_param *par)
+{
+ const struct ip6t_HL_info *info = par->targinfo;
+
+ if (info->mode > IP6T_HL_MAXMODE) {
+ printk(KERN_WARNING "ip6t_HL: invalid or unknown Mode %u\n",
+ info->mode);
+ return false;
+ }
+ 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 false;
+ }
+ return true;
+}
+
+static struct xt_target hl_tg_reg[] __read_mostly = {
+ {
+ .name = "TTL",
+ .revision = 0,
+ .family = NFPROTO_IPV4,
+ .target = ttl_tg,
+ .targetsize = sizeof(struct ipt_TTL_info),
+ .table = "mangle",
+ .checkentry = ttl_tg_check,
+ .me = THIS_MODULE,
+ },
+ {
+ .name = "HL",
+ .revision = 0,
+ .family = NFPROTO_IPV6,
+ .target = hl_tg6,
+ .targetsize = sizeof(struct ip6t_HL_info),
+ .table = "mangle",
+ .checkentry = hl_tg6_check,
+ .me = THIS_MODULE,
+ },
+};
+
+static int __init hl_tg_init(void)
+{
+ return xt_register_targets(hl_tg_reg, ARRAY_SIZE(hl_tg_reg));
+}
+
+static void __exit hl_tg_exit(void)
+{
+ xt_unregister_targets(hl_tg_reg, ARRAY_SIZE(hl_tg_reg));
+}
+
+module_init(hl_tg_init);
+module_exit(hl_tg_exit);
+MODULE_ALIAS("ipt_TTL");
+MODULE_ALIAS("ip6t_HL");