bridge/netfilter/ebt_mark.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  *  ebt_mark
0004  *
0005  *  Authors:
0006  *  Bart De Schuymer <bdschuym@pandora.be>
0007  *
0008  *  July, 2002
0009  *
0010  */
0011
0012 /* The mark target can be used in any chain,
0013  * I believe adding a mangle table just for marking is total overkill.
0014  * Marking a frame doesn't really change anything in the frame anyway.
0015  */
0016
0017 #include <linux/module.h>
0018 #include <linux/netfilter/x_tables.h>
0019 #include <linux/netfilter_bridge/ebtables.h>
0020 #include <linux/netfilter_bridge/ebt_mark_t.h>
0021
0022 static unsigned int
0023 ebt_mark_tg(struct sk_buff *skb, const struct xt_action_param *par)
0024 {
0025     const struct ebt_mark_t_info *info = par->targinfo;
0026     int action = info->target & -16;
0027
0028     if (action == MARK_SET_VALUE)
0029         skb->mark = info->mark;
0030     else if (action == MARK_OR_VALUE)
0031         skb->mark |= info->mark;
0032     else if (action == MARK_AND_VALUE)
0033         skb->mark &= info->mark;
0034     else
0035         skb->mark ^= info->mark;
0036
0037     return info->target | ~EBT_VERDICT_BITS;
0038 }
0039
0040 static int ebt_mark_tg_check(const struct xt_tgchk_param *par)
0041 {
0042     const struct ebt_mark_t_info *info = par->targinfo;
0043     int tmp;
0044
0045     tmp = info->target | ~EBT_VERDICT_BITS;
0046     if (BASE_CHAIN && tmp == EBT_RETURN)
0047         return -EINVAL;
0048     if (ebt_invalid_target(tmp))
0049         return -EINVAL;
0050     tmp = info->target & ~EBT_VERDICT_BITS;
0051     if (tmp != MARK_SET_VALUE && tmp != MARK_OR_VALUE &&
0052         tmp != MARK_AND_VALUE && tmp != MARK_XOR_VALUE)
0053         return -EINVAL;
0054     return 0;
0055 }
0056 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
0057 struct compat_ebt_mark_t_info {
0058     compat_ulong_t mark;
0059     compat_uint_t target;
0060 };
0061
0062 static void mark_tg_compat_from_user(void *dst, const void *src)
0063 {
0064     const struct compat_ebt_mark_t_info *user = src;
0065     struct ebt_mark_t_info *kern = dst;
0066
0067     kern->mark = user->mark;
0068     kern->target = user->target;
0069 }
0070
0071 static int mark_tg_compat_to_user(void __user *dst, const void *src)
0072 {
0073     struct compat_ebt_mark_t_info __user *user = dst;
0074     const struct ebt_mark_t_info *kern = src;
0075
0076     if (put_user(kern->mark, &user->mark) ||
0077         put_user(kern->target, &user->target))
0078         return -EFAULT;
0079     return 0;
0080 }
0081 #endif
0082
0083 static struct xt_target ebt_mark_tg_reg __read_mostly = {
0084     .name       = "mark",
0085     .revision   = 0,
0086     .family     = NFPROTO_BRIDGE,
0087     .target     = ebt_mark_tg,
0088     .checkentry = ebt_mark_tg_check,
0089     .targetsize = sizeof(struct ebt_mark_t_info),
0090 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
0091     .compatsize = sizeof(struct compat_ebt_mark_t_info),
0092     .compat_from_user = mark_tg_compat_from_user,
0093     .compat_to_user = mark_tg_compat_to_user,
0094 #endif
0095     .me     = THIS_MODULE,
0096 };
0097
0098 static int __init ebt_mark_init(void)
0099 {
0100     return xt_register_target(&ebt_mark_tg_reg);
0101 }
0102
0103 static void __exit ebt_mark_fini(void)
0104 {
0105     xt_unregister_target(&ebt_mark_tg_reg);
0106 }
0107
0108 module_init(ebt_mark_init);
0109 module_exit(ebt_mark_fini);
0110 MODULE_DESCRIPTION("Ebtables: Packet mark modification");
0111 MODULE_LICENSE("GPL");