1 // SPDX-License-Identifier: GPL-2.0+ 2 /* net/sched/act_ctinfo.c netfilter ctinfo connmark actions 3 * 4 * Copyright (c) 2019 Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk> 5 */ 6 7 #include <linux/module.h> 8 #include <linux/init.h> 9 #include <linux/kernel.h> 10 #include <linux/skbuff.h> 11 #include <linux/rtnetlink.h> 12 #include <linux/pkt_cls.h> 13 #include <linux/ip.h> 14 #include <linux/ipv6.h> 15 #include <net/netlink.h> 16 #include <net/pkt_sched.h> 17 #include <net/act_api.h> 18 #include <net/pkt_cls.h> 19 #include <uapi/linux/tc_act/tc_ctinfo.h> 20 #include <net/tc_act/tc_ctinfo.h> 21 #include <net/tc_wrapper.h> 22 23 #include <net/netfilter/nf_conntrack.h> 24 #include <net/netfilter/nf_conntrack_core.h> 25 #include <net/netfilter/nf_conntrack_ecache.h> 26 #include <net/netfilter/nf_conntrack_zones.h> 27 28 static struct tc_action_ops act_ctinfo_ops; 29 30 static void tcf_ctinfo_dscp_set(struct nf_conn *ct, struct tcf_ctinfo *ca, 31 struct tcf_ctinfo_params *cp, 32 struct sk_buff *skb, int wlen, int proto) 33 { 34 u8 dscp, newdscp; 35 36 newdscp = (((READ_ONCE(ct->mark) & cp->dscpmask) >> cp->dscpmaskshift) << 2) & 37 ~INET_ECN_MASK; 38 39 switch (proto) { 40 case NFPROTO_IPV4: 41 dscp = ipv4_get_dsfield(ip_hdr(skb)) & ~INET_ECN_MASK; 42 if (dscp != newdscp) { 43 if (likely(!skb_try_make_writable(skb, wlen))) { 44 ipv4_change_dsfield(ip_hdr(skb), 45 INET_ECN_MASK, 46 newdscp); 47 atomic64_inc(&ca->stats_dscp_set); 48 } else { 49 atomic64_inc(&ca->stats_dscp_error); 50 } 51 } 52 break; 53 case NFPROTO_IPV6: 54 dscp = ipv6_get_dsfield(ipv6_hdr(skb)) & ~INET_ECN_MASK; 55 if (dscp != newdscp) { 56 if (likely(!skb_try_make_writable(skb, wlen))) { 57 ipv6_change_dsfield(ipv6_hdr(skb), 58 INET_ECN_MASK, 59 newdscp); 60 atomic64_inc(&ca->stats_dscp_set); 61 } else { 62 atomic64_inc(&ca->stats_dscp_error); 63 } 64 } 65 break; 66 default: 67 break; 68 } 69 } 70 71 static void tcf_ctinfo_cpmark_set(struct nf_conn *ct, struct tcf_ctinfo *ca, 72 struct tcf_ctinfo_params *cp, 73 struct sk_buff *skb) 74 { 75 atomic64_inc(&ca->stats_cpmark_set); 76 skb->mark = READ_ONCE(ct->mark) & cp->cpmarkmask; 77 } 78 79 TC_INDIRECT_SCOPE int tcf_ctinfo_act(struct sk_buff *skb, 80 const struct tc_action *a, 81 struct tcf_result *res) 82 { 83 const struct nf_conntrack_tuple_hash *thash = NULL; 84 struct tcf_ctinfo *ca = to_ctinfo(a); 85 struct nf_conntrack_tuple tuple; 86 struct nf_conntrack_zone zone; 87 enum ip_conntrack_info ctinfo; 88 struct tcf_ctinfo_params *cp; 89 struct nf_conn *ct; 90 int proto, wlen; 91 92 cp = rcu_dereference_bh(ca->params); 93 94 tcf_lastuse_update(&ca->tcf_tm); 95 tcf_action_update_bstats(&ca->common, skb); 96 97 wlen = skb_network_offset(skb); 98 switch (skb_protocol(skb, true)) { 99 case htons(ETH_P_IP): 100 wlen += sizeof(struct iphdr); 101 if (!pskb_may_pull(skb, wlen)) 102 goto out; 103 104 proto = NFPROTO_IPV4; 105 break; 106 case htons(ETH_P_IPV6): 107 wlen += sizeof(struct ipv6hdr); 108 if (!pskb_may_pull(skb, wlen)) 109 goto out; 110 111 proto = NFPROTO_IPV6; 112 break; 113 default: 114 goto out; 115 } 116 117 ct = nf_ct_get(skb, &ctinfo); 118 if (!ct) { /* look harder, usually ingress */ 119 if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), 120 proto, cp->net, &tuple)) 121 goto out; 122 zone.id = cp->zone; 123 zone.dir = NF_CT_DEFAULT_ZONE_DIR; 124 125 thash = nf_conntrack_find_get(cp->net, &zone, &tuple); 126 if (!thash) 127 goto out; 128 129 ct = nf_ct_tuplehash_to_ctrack(thash); 130 } 131 132 if (cp->mode & CTINFO_MODE_DSCP) 133 if (!cp->dscpstatemask || (READ_ONCE(ct->mark) & cp->dscpstatemask)) 134 tcf_ctinfo_dscp_set(ct, ca, cp, skb, wlen, proto); 135 136 if (cp->mode & CTINFO_MODE_CPMARK) 137 tcf_ctinfo_cpmark_set(ct, ca, cp, skb); 138 139 if (thash) 140 nf_ct_put(ct); 141 out: 142 return cp->action; 143 } 144 145 static const struct nla_policy ctinfo_policy[TCA_CTINFO_MAX + 1] = { 146 [TCA_CTINFO_ACT] = 147 NLA_POLICY_EXACT_LEN(sizeof(struct tc_ctinfo)), 148 [TCA_CTINFO_ZONE] = { .type = NLA_U16 }, 149 [TCA_CTINFO_PARMS_DSCP_MASK] = { .type = NLA_U32 }, 150 [TCA_CTINFO_PARMS_DSCP_STATEMASK] = { .type = NLA_U32 }, 151 [TCA_CTINFO_PARMS_CPMARK_MASK] = { .type = NLA_U32 }, 152 }; 153 154 static int tcf_ctinfo_init(struct net *net, struct nlattr *nla, 155 struct nlattr *est, struct tc_action **a, 156 struct tcf_proto *tp, u32 flags, 157 struct netlink_ext_ack *extack) 158 { 159 struct tc_action_net *tn = net_generic(net, act_ctinfo_ops.net_id); 160 bool bind = flags & TCA_ACT_FLAGS_BIND; 161 u32 dscpmask = 0, dscpstatemask, index; 162 struct nlattr *tb[TCA_CTINFO_MAX + 1]; 163 struct tcf_ctinfo_params *cp_new; 164 struct tcf_chain *goto_ch = NULL; 165 struct tc_ctinfo *actparm; 166 struct tcf_ctinfo *ci; 167 u8 dscpmaskshift; 168 int ret = 0, err; 169 170 if (!nla) { 171 NL_SET_ERR_MSG_MOD(extack, "ctinfo requires attributes to be passed"); 172 return -EINVAL; 173 } 174 175 err = nla_parse_nested(tb, TCA_CTINFO_MAX, nla, ctinfo_policy, extack); 176 if (err < 0) 177 return err; 178 179 if (!tb[TCA_CTINFO_ACT]) { 180 NL_SET_ERR_MSG_MOD(extack, 181 "Missing required TCA_CTINFO_ACT attribute"); 182 return -EINVAL; 183 } 184 actparm = nla_data(tb[TCA_CTINFO_ACT]); 185 186 /* do some basic validation here before dynamically allocating things */ 187 /* that we would otherwise have to clean up. */ 188 if (tb[TCA_CTINFO_PARMS_DSCP_MASK]) { 189 dscpmask = nla_get_u32(tb[TCA_CTINFO_PARMS_DSCP_MASK]); 190 /* need contiguous 6 bit mask */ 191 dscpmaskshift = dscpmask ? __ffs(dscpmask) : 0; 192 if ((~0 & (dscpmask >> dscpmaskshift)) != 0x3f) { 193 NL_SET_ERR_MSG_ATTR(extack, 194 tb[TCA_CTINFO_PARMS_DSCP_MASK], 195 "dscp mask must be 6 contiguous bits"); 196 return -EINVAL; 197 } 198 dscpstatemask = 199 nla_get_u32_default(tb[TCA_CTINFO_PARMS_DSCP_STATEMASK], 200 0); 201 /* mask & statemask must not overlap */ 202 if (dscpmask & dscpstatemask) { 203 NL_SET_ERR_MSG_ATTR(extack, 204 tb[TCA_CTINFO_PARMS_DSCP_STATEMASK], 205 "dscp statemask must not overlap dscp mask"); 206 return -EINVAL; 207 } 208 } 209 210 /* done the validation:now to the actual action allocation */ 211 index = actparm->index; 212 err = tcf_idr_check_alloc(tn, &index, a, bind); 213 if (!err) { 214 ret = tcf_idr_create_from_flags(tn, index, est, a, 215 &act_ctinfo_ops, bind, flags); 216 if (ret) { 217 tcf_idr_cleanup(tn, index); 218 return ret; 219 } 220 ret = ACT_P_CREATED; 221 } else if (err > 0) { 222 if (bind) /* don't override defaults */ 223 return ACT_P_BOUND; 224 if (!(flags & TCA_ACT_FLAGS_REPLACE)) { 225 tcf_idr_release(*a, bind); 226 return -EEXIST; 227 } 228 } else { 229 return err; 230 } 231 232 err = tcf_action_check_ctrlact(actparm->action, tp, &goto_ch, extack); 233 if (err < 0) 234 goto release_idr; 235 236 ci = to_ctinfo(*a); 237 238 cp_new = kzalloc(sizeof(*cp_new), GFP_KERNEL); 239 if (unlikely(!cp_new)) { 240 err = -ENOMEM; 241 goto put_chain; 242 } 243 244 cp_new->net = net; 245 cp_new->zone = nla_get_u16_default(tb[TCA_CTINFO_ZONE], 0); 246 if (dscpmask) { 247 cp_new->dscpmask = dscpmask; 248 cp_new->dscpmaskshift = dscpmaskshift; 249 cp_new->dscpstatemask = dscpstatemask; 250 cp_new->mode |= CTINFO_MODE_DSCP; 251 } 252 253 if (tb[TCA_CTINFO_PARMS_CPMARK_MASK]) { 254 cp_new->cpmarkmask = 255 nla_get_u32(tb[TCA_CTINFO_PARMS_CPMARK_MASK]); 256 cp_new->mode |= CTINFO_MODE_CPMARK; 257 } 258 259 cp_new->action = actparm->action; 260 261 spin_lock_bh(&ci->tcf_lock); 262 goto_ch = tcf_action_set_ctrlact(*a, actparm->action, goto_ch); 263 cp_new = rcu_replace_pointer(ci->params, cp_new, 264 lockdep_is_held(&ci->tcf_lock)); 265 spin_unlock_bh(&ci->tcf_lock); 266 267 if (goto_ch) 268 tcf_chain_put_by_act(goto_ch); 269 if (cp_new) 270 kfree_rcu(cp_new, rcu); 271 272 return ret; 273 274 put_chain: 275 if (goto_ch) 276 tcf_chain_put_by_act(goto_ch); 277 release_idr: 278 tcf_idr_release(*a, bind); 279 return err; 280 } 281 282 static int tcf_ctinfo_dump(struct sk_buff *skb, struct tc_action *a, 283 int bind, int ref) 284 { 285 const struct tcf_ctinfo *ci = to_ctinfo(a); 286 unsigned char *b = skb_tail_pointer(skb); 287 const struct tcf_ctinfo_params *cp; 288 struct tc_ctinfo opt = { 289 .index = ci->tcf_index, 290 .refcnt = refcount_read(&ci->tcf_refcnt) - ref, 291 .bindcnt = atomic_read(&ci->tcf_bindcnt) - bind, 292 }; 293 struct tcf_t t; 294 295 rcu_read_lock(); 296 cp = rcu_dereference(ci->params); 297 298 tcf_tm_dump(&t, &ci->tcf_tm); 299 if (nla_put_64bit(skb, TCA_CTINFO_TM, sizeof(t), &t, TCA_CTINFO_PAD)) 300 goto nla_put_failure; 301 302 opt.action = cp->action; 303 if (nla_put(skb, TCA_CTINFO_ACT, sizeof(opt), &opt)) 304 goto nla_put_failure; 305 306 if (nla_put_u16(skb, TCA_CTINFO_ZONE, cp->zone)) 307 goto nla_put_failure; 308 309 if (cp->mode & CTINFO_MODE_DSCP) { 310 if (nla_put_u32(skb, TCA_CTINFO_PARMS_DSCP_MASK, 311 cp->dscpmask)) 312 goto nla_put_failure; 313 if (nla_put_u32(skb, TCA_CTINFO_PARMS_DSCP_STATEMASK, 314 cp->dscpstatemask)) 315 goto nla_put_failure; 316 } 317 318 if (cp->mode & CTINFO_MODE_CPMARK) { 319 if (nla_put_u32(skb, TCA_CTINFO_PARMS_CPMARK_MASK, 320 cp->cpmarkmask)) 321 goto nla_put_failure; 322 } 323 324 if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_DSCP_SET, 325 atomic64_read(&ci->stats_dscp_set), 326 TCA_CTINFO_PAD)) 327 goto nla_put_failure; 328 329 if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_DSCP_ERROR, 330 atomic64_read(&ci->stats_dscp_error), 331 TCA_CTINFO_PAD)) 332 goto nla_put_failure; 333 334 if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_CPMARK_SET, 335 atomic64_read(&ci->stats_cpmark_set), 336 TCA_CTINFO_PAD)) 337 goto nla_put_failure; 338 339 rcu_read_unlock(); 340 return skb->len; 341 342 nla_put_failure: 343 rcu_read_unlock(); 344 nlmsg_trim(skb, b); 345 return -1; 346 } 347 348 static void tcf_ctinfo_cleanup(struct tc_action *a) 349 { 350 struct tcf_ctinfo *ci = to_ctinfo(a); 351 struct tcf_ctinfo_params *cp; 352 353 cp = rcu_dereference_protected(ci->params, 1); 354 if (cp) 355 kfree_rcu(cp, rcu); 356 } 357 358 static struct tc_action_ops act_ctinfo_ops = { 359 .kind = "ctinfo", 360 .id = TCA_ID_CTINFO, 361 .owner = THIS_MODULE, 362 .act = tcf_ctinfo_act, 363 .dump = tcf_ctinfo_dump, 364 .init = tcf_ctinfo_init, 365 .cleanup= tcf_ctinfo_cleanup, 366 .size = sizeof(struct tcf_ctinfo), 367 }; 368 MODULE_ALIAS_NET_ACT("ctinfo"); 369 370 static __net_init int ctinfo_init_net(struct net *net) 371 { 372 struct tc_action_net *tn = net_generic(net, act_ctinfo_ops.net_id); 373 374 return tc_action_net_init(net, tn, &act_ctinfo_ops); 375 } 376 377 static void __net_exit ctinfo_exit_net(struct list_head *net_list) 378 { 379 tc_action_net_exit(net_list, act_ctinfo_ops.net_id); 380 } 381 382 static struct pernet_operations ctinfo_net_ops = { 383 .init = ctinfo_init_net, 384 .exit_batch = ctinfo_exit_net, 385 .id = &act_ctinfo_ops.net_id, 386 .size = sizeof(struct tc_action_net), 387 }; 388 389 static int __init ctinfo_init_module(void) 390 { 391 return tcf_register_action(&act_ctinfo_ops, &ctinfo_net_ops); 392 } 393 394 static void __exit ctinfo_cleanup_module(void) 395 { 396 tcf_unregister_action(&act_ctinfo_ops, &ctinfo_net_ops); 397 } 398 399 module_init(ctinfo_init_module); 400 module_exit(ctinfo_cleanup_module); 401 MODULE_AUTHOR("Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>"); 402 MODULE_DESCRIPTION("Connection tracking mark actions"); 403 MODULE_LICENSE("GPL"); 404