1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * xt_connmark - Netfilter module to operate on connection marks 4 * 5 * Copyright (C) 2002,2004 MARA Systems AB <https://www.marasystems.com> 6 * by Henrik Nordstrom <hno@marasystems.com> 7 * Copyright © CC Computer Consultants GmbH, 2007 - 2008 8 * Jan Engelhardt <jengelh@medozas.de> 9 */ 10 11 #include <linux/module.h> 12 #include <linux/skbuff.h> 13 #include <net/netfilter/nf_conntrack.h> 14 #include <net/netfilter/nf_conntrack_ecache.h> 15 #include <linux/netfilter/x_tables.h> 16 #include <linux/netfilter/xt_connmark.h> 17 18 MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>"); 19 MODULE_DESCRIPTION("Xtables: connection mark operations"); 20 MODULE_LICENSE("GPL"); 21 MODULE_ALIAS("ipt_CONNMARK"); 22 MODULE_ALIAS("ip6t_CONNMARK"); 23 MODULE_ALIAS("ipt_connmark"); 24 MODULE_ALIAS("ip6t_connmark"); 25 26 static unsigned int 27 connmark_tg_shift(struct sk_buff *skb, const struct xt_connmark_tginfo2 *info) 28 { 29 enum ip_conntrack_info ctinfo; 30 u_int32_t new_targetmark; 31 struct nf_conn *ct; 32 u_int32_t newmark; 33 u_int32_t oldmark; 34 35 ct = nf_ct_get(skb, &ctinfo); 36 if (ct == NULL) 37 return XT_CONTINUE; 38 39 switch (info->mode) { 40 case XT_CONNMARK_SET: 41 oldmark = READ_ONCE(ct->mark); 42 newmark = (oldmark & ~info->ctmask) ^ info->ctmark; 43 if (info->shift_dir == D_SHIFT_RIGHT) 44 newmark >>= info->shift_bits; 45 else 46 newmark <<= info->shift_bits; 47 48 if (READ_ONCE(ct->mark) != newmark) { 49 WRITE_ONCE(ct->mark, newmark); 50 nf_conntrack_event_cache(IPCT_MARK, ct); 51 } 52 break; 53 case XT_CONNMARK_SAVE: 54 new_targetmark = (skb->mark & info->nfmask); 55 if (info->shift_dir == D_SHIFT_RIGHT) 56 new_targetmark >>= info->shift_bits; 57 else 58 new_targetmark <<= info->shift_bits; 59 60 newmark = (READ_ONCE(ct->mark) & ~info->ctmask) ^ 61 new_targetmark; 62 if (READ_ONCE(ct->mark) != newmark) { 63 WRITE_ONCE(ct->mark, newmark); 64 nf_conntrack_event_cache(IPCT_MARK, ct); 65 } 66 break; 67 case XT_CONNMARK_RESTORE: 68 new_targetmark = (READ_ONCE(ct->mark) & info->ctmask); 69 if (info->shift_dir == D_SHIFT_RIGHT) 70 new_targetmark >>= info->shift_bits; 71 else 72 new_targetmark <<= info->shift_bits; 73 74 newmark = (skb->mark & ~info->nfmask) ^ 75 new_targetmark; 76 skb->mark = newmark; 77 break; 78 } 79 return XT_CONTINUE; 80 } 81 82 static unsigned int 83 connmark_tg(struct sk_buff *skb, const struct xt_action_param *par) 84 { 85 const struct xt_connmark_tginfo1 *info = par->targinfo; 86 const struct xt_connmark_tginfo2 info2 = { 87 .ctmark = info->ctmark, 88 .ctmask = info->ctmask, 89 .nfmask = info->nfmask, 90 .mode = info->mode, 91 }; 92 93 return connmark_tg_shift(skb, &info2); 94 } 95 96 static unsigned int 97 connmark_tg_v2(struct sk_buff *skb, const struct xt_action_param *par) 98 { 99 const struct xt_connmark_tginfo2 *info = par->targinfo; 100 101 return connmark_tg_shift(skb, info); 102 } 103 104 static int connmark_tg_check(const struct xt_tgchk_param *par) 105 { 106 int ret; 107 108 ret = nf_ct_netns_get(par->net, par->family); 109 if (ret < 0) 110 pr_info_ratelimited("cannot load conntrack support for proto=%u\n", 111 par->family); 112 return ret; 113 } 114 115 static void connmark_tg_destroy(const struct xt_tgdtor_param *par) 116 { 117 nf_ct_netns_put(par->net, par->family); 118 } 119 120 static bool 121 connmark_mt(const struct sk_buff *skb, struct xt_action_param *par) 122 { 123 const struct xt_connmark_mtinfo1 *info = par->matchinfo; 124 enum ip_conntrack_info ctinfo; 125 const struct nf_conn *ct; 126 127 ct = nf_ct_get(skb, &ctinfo); 128 if (ct == NULL) 129 return false; 130 131 return ((READ_ONCE(ct->mark) & info->mask) == info->mark) ^ info->invert; 132 } 133 134 static int connmark_mt_check(const struct xt_mtchk_param *par) 135 { 136 int ret; 137 138 ret = nf_ct_netns_get(par->net, par->family); 139 if (ret < 0) 140 pr_info_ratelimited("cannot load conntrack support for proto=%u\n", 141 par->family); 142 return ret; 143 } 144 145 static void connmark_mt_destroy(const struct xt_mtdtor_param *par) 146 { 147 nf_ct_netns_put(par->net, par->family); 148 } 149 150 static struct xt_target connmark_tg_reg[] __read_mostly = { 151 { 152 .name = "CONNMARK", 153 .revision = 1, 154 .family = NFPROTO_UNSPEC, 155 .checkentry = connmark_tg_check, 156 .target = connmark_tg, 157 .targetsize = sizeof(struct xt_connmark_tginfo1), 158 .destroy = connmark_tg_destroy, 159 .me = THIS_MODULE, 160 }, 161 { 162 .name = "CONNMARK", 163 .revision = 2, 164 .family = NFPROTO_UNSPEC, 165 .checkentry = connmark_tg_check, 166 .target = connmark_tg_v2, 167 .targetsize = sizeof(struct xt_connmark_tginfo2), 168 .destroy = connmark_tg_destroy, 169 .me = THIS_MODULE, 170 } 171 }; 172 173 static struct xt_match connmark_mt_reg __read_mostly = { 174 .name = "connmark", 175 .revision = 1, 176 .family = NFPROTO_UNSPEC, 177 .checkentry = connmark_mt_check, 178 .match = connmark_mt, 179 .matchsize = sizeof(struct xt_connmark_mtinfo1), 180 .destroy = connmark_mt_destroy, 181 .me = THIS_MODULE, 182 }; 183 184 static int __init connmark_mt_init(void) 185 { 186 int ret; 187 188 ret = xt_register_targets(connmark_tg_reg, 189 ARRAY_SIZE(connmark_tg_reg)); 190 if (ret < 0) 191 return ret; 192 ret = xt_register_match(&connmark_mt_reg); 193 if (ret < 0) { 194 xt_unregister_targets(connmark_tg_reg, 195 ARRAY_SIZE(connmark_tg_reg)); 196 return ret; 197 } 198 return 0; 199 } 200 201 static void __exit connmark_mt_exit(void) 202 { 203 xt_unregister_match(&connmark_mt_reg); 204 xt_unregister_targets(connmark_tg_reg, ARRAY_SIZE(connmark_tg_reg)); 205 } 206 207 module_init(connmark_mt_init); 208 module_exit(connmark_mt_exit); 209