1d2912cb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only
22e4e6a17SHarald Welte /* Kernel module to match packet length. */
32e4e6a17SHarald Welte /* (C) 1999-2001 James Morris <jmorros@intercode.com.au>
42e4e6a17SHarald Welte */
52e4e6a17SHarald Welte
62e4e6a17SHarald Welte #include <linux/module.h>
72e4e6a17SHarald Welte #include <linux/skbuff.h>
837d8dc82SDavid S. Miller #include <linux/ipv6.h>
92e4e6a17SHarald Welte #include <net/ip.h>
102e4e6a17SHarald Welte
112e4e6a17SHarald Welte #include <linux/netfilter/xt_length.h>
122e4e6a17SHarald Welte #include <linux/netfilter/x_tables.h>
132e4e6a17SHarald Welte
142e4e6a17SHarald Welte MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
152ae15b64SJan Engelhardt MODULE_DESCRIPTION("Xtables: Packet length (Layer3,4,5) match");
162e4e6a17SHarald Welte MODULE_LICENSE("GPL");
172e4e6a17SHarald Welte MODULE_ALIAS("ipt_length");
182e4e6a17SHarald Welte MODULE_ALIAS("ip6t_length");
192e4e6a17SHarald Welte
201d93a9cbSJan Engelhardt static bool
length_mt(const struct sk_buff * skb,struct xt_action_param * par)2162fc8051SJan Engelhardt length_mt(const struct sk_buff *skb, struct xt_action_param *par)
222e4e6a17SHarald Welte {
23f7108a20SJan Engelhardt const struct xt_length_info *info = par->matchinfo;
24eddc9ec5SArnaldo Carvalho de Melo u32 pktlen = skb_ip_totlen(skb);
252e4e6a17SHarald Welte
262e4e6a17SHarald Welte return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;
272e4e6a17SHarald Welte }
282e4e6a17SHarald Welte
291d93a9cbSJan Engelhardt static bool
length_mt6(const struct sk_buff * skb,struct xt_action_param * par)3062fc8051SJan Engelhardt length_mt6(const struct sk_buff *skb, struct xt_action_param *par)
312e4e6a17SHarald Welte {
32f7108a20SJan Engelhardt const struct xt_length_info *info = par->matchinfo;
33*05c07c0cSXin Long u32 pktlen = skb->len;
342e4e6a17SHarald Welte
352e4e6a17SHarald Welte return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;
362e4e6a17SHarald Welte }
372e4e6a17SHarald Welte
38d3c5ee6dSJan Engelhardt static struct xt_match length_mt_reg[] __read_mostly = {
394470bbc7SPatrick McHardy {
402e4e6a17SHarald Welte .name = "length",
41ee999d8bSJan Engelhardt .family = NFPROTO_IPV4,
42d3c5ee6dSJan Engelhardt .match = length_mt,
435d04bff0SPatrick McHardy .matchsize = sizeof(struct xt_length_info),
442e4e6a17SHarald Welte .me = THIS_MODULE,
454470bbc7SPatrick McHardy },
464470bbc7SPatrick McHardy {
472e4e6a17SHarald Welte .name = "length",
48ee999d8bSJan Engelhardt .family = NFPROTO_IPV6,
49d3c5ee6dSJan Engelhardt .match = length_mt6,
505d04bff0SPatrick McHardy .matchsize = sizeof(struct xt_length_info),
512e4e6a17SHarald Welte .me = THIS_MODULE,
524470bbc7SPatrick McHardy },
532e4e6a17SHarald Welte };
542e4e6a17SHarald Welte
length_mt_init(void)55d3c5ee6dSJan Engelhardt static int __init length_mt_init(void)
562e4e6a17SHarald Welte {
57d3c5ee6dSJan Engelhardt return xt_register_matches(length_mt_reg, ARRAY_SIZE(length_mt_reg));
582e4e6a17SHarald Welte }
592e4e6a17SHarald Welte
length_mt_exit(void)60d3c5ee6dSJan Engelhardt static void __exit length_mt_exit(void)
612e4e6a17SHarald Welte {
62d3c5ee6dSJan Engelhardt xt_unregister_matches(length_mt_reg, ARRAY_SIZE(length_mt_reg));
632e4e6a17SHarald Welte }
642e4e6a17SHarald Welte
65d3c5ee6dSJan Engelhardt module_init(length_mt_init);
66d3c5ee6dSJan Engelhardt module_exit(length_mt_exit);
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