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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 | // SPDX-License-Identifier: GPL-2.0-only /* * xt_HMARK - Netfilter module to set mark by means of hashing * * (C) 2012 by Hans Schillstrom <hans.schillstrom@ericsson.com> * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org> */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h> #include <linux/skbuff.h> #include <linux/icmp.h> #include <linux/netfilter/x_tables.h> #include <linux/netfilter/xt_HMARK.h> #include <net/ip.h> #if IS_ENABLED(CONFIG_NF_CONNTRACK) #include <net/netfilter/nf_conntrack.h> #endif #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) #include <net/ipv6.h> #include <linux/netfilter_ipv6/ip6_tables.h> #endif MODULE_LICENSE("GPL"); MODULE_AUTHOR("Hans Schillstrom <hans.schillstrom@ericsson.com>"); MODULE_DESCRIPTION("Xtables: packet marking using hash calculation"); MODULE_ALIAS("ipt_HMARK"); MODULE_ALIAS("ip6t_HMARK"); struct hmark_tuple { __be32 src; __be32 dst; union hmark_ports uports; u8 proto; }; static inline __be32 hmark_addr6_mask(const __be32 *addr32, const __be32 *mask) { return (addr32[0] & mask[0]) ^ (addr32[1] & mask[1]) ^ (addr32[2] & mask[2]) ^ (addr32[3] & mask[3]); } static inline __be32 hmark_addr_mask(int l3num, const __be32 *addr32, const __be32 *mask) { switch (l3num) { case AF_INET: return *addr32 & *mask; case AF_INET6: return hmark_addr6_mask(addr32, mask); } return 0; } static inline void hmark_swap_ports(union hmark_ports *uports, const struct xt_hmark_info *info) { union hmark_ports hp; u16 src, dst; hp.b32 = (uports->b32 & info->port_mask.b32) | info->port_set.b32; src = ntohs(hp.b16.src); dst = ntohs(hp.b16.dst); if (dst > src) uports->v32 = (dst << 16) | src; else uports->v32 = (src << 16) | dst; } static int hmark_ct_set_htuple(const struct sk_buff *skb, struct hmark_tuple *t, const struct xt_hmark_info *info) { #if IS_ENABLED(CONFIG_NF_CONNTRACK) enum ip_conntrack_info ctinfo; struct nf_conn *ct = nf_ct_get(skb, &ctinfo); struct nf_conntrack_tuple *otuple; struct nf_conntrack_tuple *rtuple; if (ct == NULL) return -1; otuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; rtuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple; t->src = hmark_addr_mask(otuple->src.l3num, otuple->src.u3.ip6, info->src_mask.ip6); t->dst = hmark_addr_mask(otuple->src.l3num, rtuple->src.u3.ip6, info->dst_mask.ip6); if (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3)) return 0; t->proto = nf_ct_protonum(ct); if (t->proto != IPPROTO_ICMP) { t->uports.b16.src = otuple->src.u.all; t->uports.b16.dst = rtuple->src.u.all; hmark_swap_ports(&t->uports, info); } return 0; #else return -1; #endif } /* This hash function is endian independent, to ensure consistent hashing if * the cluster is composed of big and little endian systems. */ static inline u32 hmark_hash(struct hmark_tuple *t, const struct xt_hmark_info *info) { u32 hash; u32 src = ntohl(t->src); u32 dst = ntohl(t->dst); if (dst < src) swap(src, dst); hash = jhash_3words(src, dst, t->uports.v32, info->hashrnd); hash = hash ^ (t->proto & info->proto_mask); return reciprocal_scale(hash, info->hmodulus) + info->hoffset; } static void hmark_set_tuple_ports(const struct sk_buff *skb, unsigned int nhoff, struct hmark_tuple *t, const struct xt_hmark_info *info) { int protoff; protoff = proto_ports_offset(t->proto); if (protoff < 0) return; nhoff += protoff; if (skb_copy_bits(skb, nhoff, &t->uports, sizeof(t->uports)) < 0) return; hmark_swap_ports(&t->uports, info); } #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) static int get_inner6_hdr(const struct sk_buff *skb, int *offset) { struct icmp6hdr *icmp6h, _ih6; icmp6h = skb_header_pointer(skb, *offset, sizeof(_ih6), &_ih6); if (icmp6h == NULL) return 0; if (icmp6h->icmp6_type && icmp6h->icmp6_type < 128) { *offset += sizeof(struct icmp6hdr); return 1; } return 0; } static int hmark_pkt_set_htuple_ipv6(const struct sk_buff *skb, struct hmark_tuple *t, const struct xt_hmark_info *info) { struct ipv6hdr *ip6, _ip6; int flag = IP6_FH_F_AUTH; unsigned int nhoff = 0; u16 fragoff = 0; int nexthdr; ip6 = (struct ipv6hdr *) (skb->data + skb_network_offset(skb)); nexthdr = ipv6_find_hdr(skb, &nhoff, -1, &fragoff, &flag); if (nexthdr < 0) return 0; /* No need to check for icmp errors on fragments */ if ((flag & IP6_FH_F_FRAG) || (nexthdr != IPPROTO_ICMPV6)) goto noicmp; /* Use inner header in case of ICMP errors */ if (get_inner6_hdr(skb, &nhoff)) { ip6 = skb_header_pointer(skb, nhoff, sizeof(_ip6), &_ip6); if (ip6 == NULL) return -1; /* If AH present, use SPI like in ESP. */ flag = IP6_FH_F_AUTH; nexthdr = ipv6_find_hdr(skb, &nhoff, -1, &fragoff, &flag); if (nexthdr < 0) return -1; } noicmp: t->src = hmark_addr6_mask(ip6->saddr.s6_addr32, info->src_mask.ip6); t->dst = hmark_addr6_mask(ip6->daddr.s6_addr32, info->dst_mask.ip6); if (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3)) return 0; t->proto = nexthdr; if (t->proto == IPPROTO_ICMPV6) return 0; if (flag & IP6_FH_F_FRAG) return 0; hmark_set_tuple_ports(skb, nhoff, t, info); return 0; } static unsigned int hmark_tg_v6(struct sk_buff *skb, const struct xt_action_param *par) { const struct xt_hmark_info *info = par->targinfo; struct hmark_tuple t; memset(&t, 0, sizeof(struct hmark_tuple)); if (info->flags & XT_HMARK_FLAG(XT_HMARK_CT)) { if (hmark_ct_set_htuple(skb, &t, info) < 0) return XT_CONTINUE; } else { if (hmark_pkt_set_htuple_ipv6(skb, &t, info) < 0) return XT_CONTINUE; } skb->mark = hmark_hash(&t, info); return XT_CONTINUE; } #endif static int get_inner_hdr(const struct sk_buff *skb, int iphsz, int *nhoff) { const struct icmphdr *icmph; struct icmphdr _ih; /* Not enough header? */ icmph = skb_header_pointer(skb, *nhoff + iphsz, sizeof(_ih), &_ih); if (icmph == NULL || icmph->type > NR_ICMP_TYPES) return 0; /* Error message? */ if (icmph->type != ICMP_DEST_UNREACH && icmph->type != ICMP_SOURCE_QUENCH && icmph->type != ICMP_TIME_EXCEEDED && icmph->type != ICMP_PARAMETERPROB && icmph->type != ICMP_REDIRECT) return 0; *nhoff += iphsz + sizeof(_ih); return 1; } static int hmark_pkt_set_htuple_ipv4(const struct sk_buff *skb, struct hmark_tuple *t, const struct xt_hmark_info *info) { struct iphdr *ip, _ip; int nhoff = skb_network_offset(skb); ip = (struct iphdr *) (skb->data + nhoff); if (ip->protocol == IPPROTO_ICMP) { /* Use inner header in case of ICMP errors */ if (get_inner_hdr(skb, ip->ihl * 4, &nhoff)) { ip = skb_header_pointer(skb, nhoff, sizeof(_ip), &_ip); if (ip == NULL) return -1; } } t->src = ip->saddr & info->src_mask.ip; t->dst = ip->daddr & info->dst_mask.ip; if (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3)) return 0; t->proto = ip->protocol; /* ICMP has no ports, skip */ if (t->proto == IPPROTO_ICMP) return 0; /* follow-up fragments don't contain ports, skip all fragments */ if (ip->frag_off & htons(IP_MF | IP_OFFSET)) return 0; hmark_set_tuple_ports(skb, (ip->ihl * 4) + nhoff, t, info); return 0; } static unsigned int hmark_tg_v4(struct sk_buff *skb, const struct xt_action_param *par) { const struct xt_hmark_info *info = par->targinfo; struct hmark_tuple t; memset(&t, 0, sizeof(struct hmark_tuple)); if (info->flags & XT_HMARK_FLAG(XT_HMARK_CT)) { if (hmark_ct_set_htuple(skb, &t, info) < 0) return XT_CONTINUE; } else { if (hmark_pkt_set_htuple_ipv4(skb, &t, info) < 0) return XT_CONTINUE; } skb->mark = hmark_hash(&t, info); return XT_CONTINUE; } static int hmark_tg_check(const struct xt_tgchk_param *par) { const struct xt_hmark_info *info = par->targinfo; const char *errmsg = "proto mask must be zero with L3 mode"; if (!info->hmodulus) return -EINVAL; if (info->proto_mask && (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3))) goto err; if (info->flags & XT_HMARK_FLAG(XT_HMARK_SPI_MASK) && (info->flags & (XT_HMARK_FLAG(XT_HMARK_SPORT_MASK) | XT_HMARK_FLAG(XT_HMARK_DPORT_MASK)))) return -EINVAL; if (info->flags & XT_HMARK_FLAG(XT_HMARK_SPI) && (info->flags & (XT_HMARK_FLAG(XT_HMARK_SPORT) | XT_HMARK_FLAG(XT_HMARK_DPORT)))) { errmsg = "spi-set and port-set can't be combined"; goto err; } return 0; err: pr_info_ratelimited("%s\n", errmsg); return -EINVAL; } static struct xt_target hmark_tg_reg[] __read_mostly = { { .name = "HMARK", .family = NFPROTO_IPV4, .target = hmark_tg_v4, .targetsize = sizeof(struct xt_hmark_info), .checkentry = hmark_tg_check, .me = THIS_MODULE, }, #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) { .name = "HMARK", .family = NFPROTO_IPV6, .target = hmark_tg_v6, .targetsize = sizeof(struct xt_hmark_info), .checkentry = hmark_tg_check, .me = THIS_MODULE, }, #endif }; static int __init hmark_tg_init(void) { return xt_register_targets(hmark_tg_reg, ARRAY_SIZE(hmark_tg_reg)); } static void __exit hmark_tg_exit(void) { xt_unregister_targets(hmark_tg_reg, ARRAY_SIZE(hmark_tg_reg)); } module_init(hmark_tg_init); module_exit(hmark_tg_exit); |