1 /* 2 * Copyright (c) 2015 Patrick McHardy <[email protected]> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/module.h> 12 #include <linux/init.h> 13 #include <linux/netlink.h> 14 #include <linux/netfilter.h> 15 #include <linux/netfilter/nf_tables.h> 16 #include <net/netfilter/nf_tables.h> 17 #include <net/netfilter/nf_tables_core.h> 18 19 struct nft_dynset { 20 struct nft_set *set; 21 struct nft_set_ext_tmpl tmpl; 22 enum nft_dynset_ops op:8; 23 enum nft_registers sreg_key:8; 24 enum nft_registers sreg_data:8; 25 bool invert; 26 u64 timeout; 27 struct nft_expr *expr; 28 struct nft_set_binding binding; 29 }; 30 31 static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr, 32 struct nft_regs *regs) 33 { 34 const struct nft_dynset *priv = nft_expr_priv(expr); 35 struct nft_set_ext *ext; 36 u64 timeout; 37 void *elem; 38 39 if (set->size && !atomic_add_unless(&set->nelems, 1, set->size)) 40 return NULL; 41 42 timeout = priv->timeout ? : set->timeout; 43 elem = nft_set_elem_init(set, &priv->tmpl, 44 ®s->data[priv->sreg_key], 45 ®s->data[priv->sreg_data], 46 timeout, GFP_ATOMIC); 47 if (elem == NULL) 48 goto err1; 49 50 ext = nft_set_elem_ext(set, elem); 51 if (priv->expr != NULL && 52 nft_expr_clone(nft_set_ext_expr(ext), priv->expr) < 0) 53 goto err2; 54 55 return elem; 56 57 err2: 58 nft_set_elem_destroy(set, elem, false); 59 err1: 60 if (set->size) 61 atomic_dec(&set->nelems); 62 return NULL; 63 } 64 65 static void nft_dynset_eval(const struct nft_expr *expr, 66 struct nft_regs *regs, 67 const struct nft_pktinfo *pkt) 68 { 69 const struct nft_dynset *priv = nft_expr_priv(expr); 70 struct nft_set *set = priv->set; 71 const struct nft_set_ext *ext; 72 const struct nft_expr *sexpr; 73 u64 timeout; 74 75 if (set->ops->update(set, ®s->data[priv->sreg_key], nft_dynset_new, 76 expr, regs, &ext)) { 77 sexpr = NULL; 78 if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPR)) 79 sexpr = nft_set_ext_expr(ext); 80 81 if (priv->op == NFT_DYNSET_OP_UPDATE && 82 nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) { 83 timeout = priv->timeout ? : set->timeout; 84 *nft_set_ext_expiration(ext) = jiffies + timeout; 85 } 86 87 if (sexpr != NULL) 88 sexpr->ops->eval(sexpr, regs, pkt); 89 90 if (priv->invert) 91 regs->verdict.code = NFT_BREAK; 92 return; 93 } 94 95 if (!priv->invert) 96 regs->verdict.code = NFT_BREAK; 97 } 98 99 static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = { 100 [NFTA_DYNSET_SET_NAME] = { .type = NLA_STRING, 101 .len = NFT_SET_MAXNAMELEN - 1 }, 102 [NFTA_DYNSET_SET_ID] = { .type = NLA_U32 }, 103 [NFTA_DYNSET_OP] = { .type = NLA_U32 }, 104 [NFTA_DYNSET_SREG_KEY] = { .type = NLA_U32 }, 105 [NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 }, 106 [NFTA_DYNSET_TIMEOUT] = { .type = NLA_U64 }, 107 [NFTA_DYNSET_EXPR] = { .type = NLA_NESTED }, 108 [NFTA_DYNSET_FLAGS] = { .type = NLA_U32 }, 109 }; 110 111 static int nft_dynset_init(const struct nft_ctx *ctx, 112 const struct nft_expr *expr, 113 const struct nlattr * const tb[]) 114 { 115 struct nft_dynset *priv = nft_expr_priv(expr); 116 u8 genmask = nft_genmask_next(ctx->net); 117 struct nft_set *set; 118 u64 timeout; 119 int err; 120 121 if (tb[NFTA_DYNSET_SET_NAME] == NULL || 122 tb[NFTA_DYNSET_OP] == NULL || 123 tb[NFTA_DYNSET_SREG_KEY] == NULL) 124 return -EINVAL; 125 126 if (tb[NFTA_DYNSET_FLAGS]) { 127 u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS])); 128 129 if (flags & ~NFT_DYNSET_F_INV) 130 return -EINVAL; 131 if (flags & NFT_DYNSET_F_INV) 132 priv->invert = true; 133 } 134 135 set = nft_set_lookup(ctx->net, ctx->table, tb[NFTA_DYNSET_SET_NAME], 136 tb[NFTA_DYNSET_SET_ID], genmask); 137 if (IS_ERR(set)) 138 return PTR_ERR(set); 139 140 if (set->ops->update == NULL) 141 return -EOPNOTSUPP; 142 143 if (set->flags & NFT_SET_CONSTANT) 144 return -EBUSY; 145 146 priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP])); 147 switch (priv->op) { 148 case NFT_DYNSET_OP_ADD: 149 break; 150 case NFT_DYNSET_OP_UPDATE: 151 if (!(set->flags & NFT_SET_TIMEOUT)) 152 return -EOPNOTSUPP; 153 break; 154 default: 155 return -EOPNOTSUPP; 156 } 157 158 timeout = 0; 159 if (tb[NFTA_DYNSET_TIMEOUT] != NULL) { 160 if (!(set->flags & NFT_SET_TIMEOUT)) 161 return -EINVAL; 162 timeout = msecs_to_jiffies(be64_to_cpu(nla_get_be64( 163 tb[NFTA_DYNSET_TIMEOUT]))); 164 } 165 166 priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]); 167 err = nft_validate_register_load(priv->sreg_key, set->klen);; 168 if (err < 0) 169 return err; 170 171 if (tb[NFTA_DYNSET_SREG_DATA] != NULL) { 172 if (!(set->flags & NFT_SET_MAP)) 173 return -EINVAL; 174 if (set->dtype == NFT_DATA_VERDICT) 175 return -EOPNOTSUPP; 176 177 priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]); 178 err = nft_validate_register_load(priv->sreg_data, set->dlen); 179 if (err < 0) 180 return err; 181 } else if (set->flags & NFT_SET_MAP) 182 return -EINVAL; 183 184 if (tb[NFTA_DYNSET_EXPR] != NULL) { 185 if (!(set->flags & NFT_SET_EVAL)) 186 return -EINVAL; 187 if (!(set->flags & NFT_SET_ANONYMOUS)) 188 return -EOPNOTSUPP; 189 190 priv->expr = nft_expr_init(ctx, tb[NFTA_DYNSET_EXPR]); 191 if (IS_ERR(priv->expr)) 192 return PTR_ERR(priv->expr); 193 194 err = -EOPNOTSUPP; 195 if (!(priv->expr->ops->type->flags & NFT_EXPR_STATEFUL)) 196 goto err1; 197 } else if (set->flags & NFT_SET_EVAL) 198 return -EINVAL; 199 200 nft_set_ext_prepare(&priv->tmpl); 201 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen); 202 if (set->flags & NFT_SET_MAP) 203 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen); 204 if (priv->expr != NULL) 205 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR, 206 priv->expr->ops->size); 207 if (set->flags & NFT_SET_TIMEOUT) { 208 if (timeout || set->timeout) 209 nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION); 210 } 211 212 priv->timeout = timeout; 213 214 err = nf_tables_bind_set(ctx, set, &priv->binding); 215 if (err < 0) 216 goto err1; 217 218 priv->set = set; 219 return 0; 220 221 err1: 222 if (priv->expr != NULL) 223 nft_expr_destroy(ctx, priv->expr); 224 return err; 225 } 226 227 static void nft_dynset_destroy(const struct nft_ctx *ctx, 228 const struct nft_expr *expr) 229 { 230 struct nft_dynset *priv = nft_expr_priv(expr); 231 232 nf_tables_unbind_set(ctx, priv->set, &priv->binding); 233 if (priv->expr != NULL) 234 nft_expr_destroy(ctx, priv->expr); 235 } 236 237 static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr) 238 { 239 const struct nft_dynset *priv = nft_expr_priv(expr); 240 u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0; 241 242 if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key)) 243 goto nla_put_failure; 244 if (priv->set->flags & NFT_SET_MAP && 245 nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data)) 246 goto nla_put_failure; 247 if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op))) 248 goto nla_put_failure; 249 if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name)) 250 goto nla_put_failure; 251 if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT, 252 cpu_to_be64(jiffies_to_msecs(priv->timeout)), 253 NFTA_DYNSET_PAD)) 254 goto nla_put_failure; 255 if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr)) 256 goto nla_put_failure; 257 if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags))) 258 goto nla_put_failure; 259 return 0; 260 261 nla_put_failure: 262 return -1; 263 } 264 265 static const struct nft_expr_ops nft_dynset_ops = { 266 .type = &nft_dynset_type, 267 .size = NFT_EXPR_SIZE(sizeof(struct nft_dynset)), 268 .eval = nft_dynset_eval, 269 .init = nft_dynset_init, 270 .destroy = nft_dynset_destroy, 271 .dump = nft_dynset_dump, 272 }; 273 274 struct nft_expr_type nft_dynset_type __read_mostly = { 275 .name = "dynset", 276 .ops = &nft_dynset_ops, 277 .policy = nft_dynset_policy, 278 .maxattr = NFTA_DYNSET_MAX, 279 .owner = THIS_MODULE, 280 }; 281