1 /* 2 * Copyright (c) 2015 Patrick McHardy <kaber@trash.net> 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 u64 timeout; 26 struct nft_expr *expr; 27 struct nft_set_binding binding; 28 }; 29 30 static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr, 31 struct nft_regs *regs) 32 { 33 const struct nft_dynset *priv = nft_expr_priv(expr); 34 struct nft_set_ext *ext; 35 u64 timeout; 36 void *elem; 37 38 if (set->size && !atomic_add_unless(&set->nelems, 1, set->size)) 39 return NULL; 40 41 timeout = priv->timeout ? : set->timeout; 42 elem = nft_set_elem_init(set, &priv->tmpl, 43 ®s->data[priv->sreg_key], 44 ®s->data[priv->sreg_data], 45 timeout, GFP_ATOMIC); 46 if (elem == NULL) { 47 if (set->size) 48 atomic_dec(&set->nelems); 49 return NULL; 50 } 51 52 ext = nft_set_elem_ext(set, elem); 53 if (priv->expr != NULL) 54 nft_expr_clone(nft_set_ext_expr(ext), priv->expr); 55 56 return elem; 57 } 58 59 static void nft_dynset_eval(const struct nft_expr *expr, 60 struct nft_regs *regs, 61 const struct nft_pktinfo *pkt) 62 { 63 const struct nft_dynset *priv = nft_expr_priv(expr); 64 struct nft_set *set = priv->set; 65 const struct nft_set_ext *ext; 66 const struct nft_expr *sexpr; 67 u64 timeout; 68 69 if (set->ops->update(set, ®s->data[priv->sreg_key], nft_dynset_new, 70 expr, regs, &ext)) { 71 sexpr = NULL; 72 if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPR)) 73 sexpr = nft_set_ext_expr(ext); 74 75 if (priv->op == NFT_DYNSET_OP_UPDATE && 76 nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) { 77 timeout = priv->timeout ? : set->timeout; 78 *nft_set_ext_expiration(ext) = jiffies + timeout; 79 } else if (sexpr == NULL) 80 goto out; 81 82 if (sexpr != NULL) 83 sexpr->ops->eval(sexpr, regs, pkt); 84 return; 85 } 86 out: 87 regs->verdict.code = NFT_BREAK; 88 } 89 90 static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = { 91 [NFTA_DYNSET_SET_NAME] = { .type = NLA_STRING }, 92 [NFTA_DYNSET_SET_ID] = { .type = NLA_U32 }, 93 [NFTA_DYNSET_OP] = { .type = NLA_U32 }, 94 [NFTA_DYNSET_SREG_KEY] = { .type = NLA_U32 }, 95 [NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 }, 96 [NFTA_DYNSET_TIMEOUT] = { .type = NLA_U64 }, 97 [NFTA_DYNSET_EXPR] = { .type = NLA_NESTED }, 98 }; 99 100 static int nft_dynset_init(const struct nft_ctx *ctx, 101 const struct nft_expr *expr, 102 const struct nlattr * const tb[]) 103 { 104 struct nft_dynset *priv = nft_expr_priv(expr); 105 struct nft_set *set; 106 u64 timeout; 107 int err; 108 109 if (tb[NFTA_DYNSET_SET_NAME] == NULL || 110 tb[NFTA_DYNSET_OP] == NULL || 111 tb[NFTA_DYNSET_SREG_KEY] == NULL) 112 return -EINVAL; 113 114 set = nf_tables_set_lookup(ctx->table, tb[NFTA_DYNSET_SET_NAME]); 115 if (IS_ERR(set)) { 116 if (tb[NFTA_DYNSET_SET_ID]) 117 set = nf_tables_set_lookup_byid(ctx->net, 118 tb[NFTA_DYNSET_SET_ID]); 119 if (IS_ERR(set)) 120 return PTR_ERR(set); 121 } 122 123 if (set->flags & NFT_SET_CONSTANT) 124 return -EBUSY; 125 126 priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP])); 127 switch (priv->op) { 128 case NFT_DYNSET_OP_ADD: 129 break; 130 case NFT_DYNSET_OP_UPDATE: 131 if (!(set->flags & NFT_SET_TIMEOUT)) 132 return -EOPNOTSUPP; 133 break; 134 default: 135 return -EOPNOTSUPP; 136 } 137 138 timeout = 0; 139 if (tb[NFTA_DYNSET_TIMEOUT] != NULL) { 140 if (!(set->flags & NFT_SET_TIMEOUT)) 141 return -EINVAL; 142 timeout = be64_to_cpu(nla_get_be64(tb[NFTA_DYNSET_TIMEOUT])); 143 } 144 145 priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]); 146 err = nft_validate_register_load(priv->sreg_key, set->klen);; 147 if (err < 0) 148 return err; 149 150 if (tb[NFTA_DYNSET_SREG_DATA] != NULL) { 151 if (!(set->flags & NFT_SET_MAP)) 152 return -EINVAL; 153 if (set->dtype == NFT_DATA_VERDICT) 154 return -EOPNOTSUPP; 155 156 priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]); 157 err = nft_validate_register_load(priv->sreg_data, set->dlen); 158 if (err < 0) 159 return err; 160 } else if (set->flags & NFT_SET_MAP) 161 return -EINVAL; 162 163 if (tb[NFTA_DYNSET_EXPR] != NULL) { 164 if (!(set->flags & NFT_SET_EVAL)) 165 return -EINVAL; 166 if (!(set->flags & NFT_SET_ANONYMOUS)) 167 return -EOPNOTSUPP; 168 169 priv->expr = nft_expr_init(ctx, tb[NFTA_DYNSET_EXPR]); 170 if (IS_ERR(priv->expr)) 171 return PTR_ERR(priv->expr); 172 173 err = -EOPNOTSUPP; 174 if (!(priv->expr->ops->type->flags & NFT_EXPR_STATEFUL)) 175 goto err1; 176 } else if (set->flags & NFT_SET_EVAL) 177 return -EINVAL; 178 179 nft_set_ext_prepare(&priv->tmpl); 180 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen); 181 if (set->flags & NFT_SET_MAP) 182 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen); 183 if (priv->expr != NULL) 184 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR, 185 priv->expr->ops->size); 186 if (set->flags & NFT_SET_TIMEOUT) { 187 if (timeout || set->timeout) 188 nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION); 189 } 190 191 priv->timeout = timeout; 192 193 err = nf_tables_bind_set(ctx, set, &priv->binding); 194 if (err < 0) 195 goto err1; 196 197 priv->set = set; 198 return 0; 199 200 err1: 201 if (priv->expr != NULL) 202 nft_expr_destroy(ctx, priv->expr); 203 return err; 204 } 205 206 static void nft_dynset_destroy(const struct nft_ctx *ctx, 207 const struct nft_expr *expr) 208 { 209 struct nft_dynset *priv = nft_expr_priv(expr); 210 211 nf_tables_unbind_set(ctx, priv->set, &priv->binding); 212 if (priv->expr != NULL) 213 nft_expr_destroy(ctx, priv->expr); 214 } 215 216 static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr) 217 { 218 const struct nft_dynset *priv = nft_expr_priv(expr); 219 220 if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key)) 221 goto nla_put_failure; 222 if (priv->set->flags & NFT_SET_MAP && 223 nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data)) 224 goto nla_put_failure; 225 if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op))) 226 goto nla_put_failure; 227 if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name)) 228 goto nla_put_failure; 229 if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT, cpu_to_be64(priv->timeout))) 230 goto nla_put_failure; 231 if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr)) 232 goto nla_put_failure; 233 return 0; 234 235 nla_put_failure: 236 return -1; 237 } 238 239 static struct nft_expr_type nft_dynset_type; 240 static const struct nft_expr_ops nft_dynset_ops = { 241 .type = &nft_dynset_type, 242 .size = NFT_EXPR_SIZE(sizeof(struct nft_dynset)), 243 .eval = nft_dynset_eval, 244 .init = nft_dynset_init, 245 .destroy = nft_dynset_destroy, 246 .dump = nft_dynset_dump, 247 }; 248 249 static struct nft_expr_type nft_dynset_type __read_mostly = { 250 .name = "dynset", 251 .ops = &nft_dynset_ops, 252 .policy = nft_dynset_policy, 253 .maxattr = NFTA_DYNSET_MAX, 254 .owner = THIS_MODULE, 255 }; 256 257 int __init nft_dynset_module_init(void) 258 { 259 return nft_register_expr(&nft_dynset_type); 260 } 261 262 void nft_dynset_module_exit(void) 263 { 264 nft_unregister_expr(&nft_dynset_type); 265 } 266