1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> 4 * 5 * Development of this code funded by Astaro AG (http://www.astaro.com/) 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/init.h> 10 #include <linux/module.h> 11 #include <linux/netlink.h> 12 #include <linux/netfilter.h> 13 #include <linux/if_arp.h> 14 #include <linux/netfilter/nf_tables.h> 15 #include <net/netfilter/nf_tables_core.h> 16 #include <net/netfilter/nf_tables_offload.h> 17 #include <net/netfilter/nf_tables.h> 18 19 struct nft_cmp_expr { 20 struct nft_data data; 21 u8 sreg; 22 u8 len; 23 enum nft_cmp_ops op:8; 24 }; 25 26 void nft_cmp_eval(const struct nft_expr *expr, 27 struct nft_regs *regs, 28 const struct nft_pktinfo *pkt) 29 { 30 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 31 int d; 32 33 d = memcmp(®s->data[priv->sreg], &priv->data, priv->len); 34 switch (priv->op) { 35 case NFT_CMP_EQ: 36 if (d != 0) 37 goto mismatch; 38 break; 39 case NFT_CMP_NEQ: 40 if (d == 0) 41 goto mismatch; 42 break; 43 case NFT_CMP_LT: 44 if (d == 0) 45 goto mismatch; 46 fallthrough; 47 case NFT_CMP_LTE: 48 if (d > 0) 49 goto mismatch; 50 break; 51 case NFT_CMP_GT: 52 if (d == 0) 53 goto mismatch; 54 fallthrough; 55 case NFT_CMP_GTE: 56 if (d < 0) 57 goto mismatch; 58 break; 59 } 60 return; 61 62 mismatch: 63 regs->verdict.code = NFT_BREAK; 64 } 65 66 static const struct nla_policy nft_cmp_policy[NFTA_CMP_MAX + 1] = { 67 [NFTA_CMP_SREG] = { .type = NLA_U32 }, 68 [NFTA_CMP_OP] = { .type = NLA_U32 }, 69 [NFTA_CMP_DATA] = { .type = NLA_NESTED }, 70 }; 71 72 static int nft_cmp_init(const struct nft_ctx *ctx, const struct nft_expr *expr, 73 const struct nlattr * const tb[]) 74 { 75 struct nft_cmp_expr *priv = nft_expr_priv(expr); 76 struct nft_data_desc desc; 77 int err; 78 79 err = nft_data_init(NULL, &priv->data, sizeof(priv->data), &desc, 80 tb[NFTA_CMP_DATA]); 81 if (err < 0) 82 return err; 83 84 if (desc.type != NFT_DATA_VALUE) { 85 err = -EINVAL; 86 nft_data_release(&priv->data, desc.type); 87 return err; 88 } 89 90 err = nft_parse_register_load(tb[NFTA_CMP_SREG], &priv->sreg, desc.len); 91 if (err < 0) 92 return err; 93 94 priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 95 priv->len = desc.len; 96 return 0; 97 } 98 99 static int nft_cmp_dump(struct sk_buff *skb, const struct nft_expr *expr) 100 { 101 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 102 103 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 104 goto nla_put_failure; 105 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op))) 106 goto nla_put_failure; 107 108 if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data, 109 NFT_DATA_VALUE, priv->len) < 0) 110 goto nla_put_failure; 111 return 0; 112 113 nla_put_failure: 114 return -1; 115 } 116 117 static int __nft_cmp_offload(struct nft_offload_ctx *ctx, 118 struct nft_flow_rule *flow, 119 const struct nft_cmp_expr *priv) 120 { 121 struct nft_offload_reg *reg = &ctx->regs[priv->sreg]; 122 u8 *mask = (u8 *)&flow->match.mask; 123 u8 *key = (u8 *)&flow->match.key; 124 125 if (priv->op != NFT_CMP_EQ || priv->len > reg->len) 126 return -EOPNOTSUPP; 127 128 memcpy(key + reg->offset, &priv->data, reg->len); 129 memcpy(mask + reg->offset, ®->mask, reg->len); 130 131 flow->match.dissector.used_keys |= BIT(reg->key); 132 flow->match.dissector.offset[reg->key] = reg->base_offset; 133 134 if (reg->key == FLOW_DISSECTOR_KEY_META && 135 reg->offset == offsetof(struct nft_flow_key, meta.ingress_iftype) && 136 nft_reg_load16(priv->data.data) != ARPHRD_ETHER) 137 return -EOPNOTSUPP; 138 139 nft_offload_update_dependency(ctx, &priv->data, reg->len); 140 141 return 0; 142 } 143 144 static int nft_cmp_offload(struct nft_offload_ctx *ctx, 145 struct nft_flow_rule *flow, 146 const struct nft_expr *expr) 147 { 148 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 149 150 return __nft_cmp_offload(ctx, flow, priv); 151 } 152 153 static const struct nft_expr_ops nft_cmp_ops = { 154 .type = &nft_cmp_type, 155 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)), 156 .eval = nft_cmp_eval, 157 .init = nft_cmp_init, 158 .dump = nft_cmp_dump, 159 .offload = nft_cmp_offload, 160 }; 161 162 static int nft_cmp_fast_init(const struct nft_ctx *ctx, 163 const struct nft_expr *expr, 164 const struct nlattr * const tb[]) 165 { 166 struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 167 struct nft_data_desc desc; 168 struct nft_data data; 169 int err; 170 171 err = nft_data_init(NULL, &data, sizeof(data), &desc, 172 tb[NFTA_CMP_DATA]); 173 if (err < 0) 174 return err; 175 176 err = nft_parse_register_load(tb[NFTA_CMP_SREG], &priv->sreg, desc.len); 177 if (err < 0) 178 return err; 179 180 desc.len *= BITS_PER_BYTE; 181 182 priv->mask = nft_cmp_fast_mask(desc.len); 183 priv->data = data.data[0] & priv->mask; 184 priv->len = desc.len; 185 priv->inv = ntohl(nla_get_be32(tb[NFTA_CMP_OP])) != NFT_CMP_EQ; 186 return 0; 187 } 188 189 static int nft_cmp_fast_offload(struct nft_offload_ctx *ctx, 190 struct nft_flow_rule *flow, 191 const struct nft_expr *expr) 192 { 193 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 194 struct nft_cmp_expr cmp = { 195 .data = { 196 .data = { 197 [0] = priv->data, 198 }, 199 }, 200 .sreg = priv->sreg, 201 .len = priv->len / BITS_PER_BYTE, 202 .op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ, 203 }; 204 205 return __nft_cmp_offload(ctx, flow, &cmp); 206 } 207 208 static int nft_cmp_fast_dump(struct sk_buff *skb, const struct nft_expr *expr) 209 { 210 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 211 enum nft_cmp_ops op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ; 212 struct nft_data data; 213 214 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 215 goto nla_put_failure; 216 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(op))) 217 goto nla_put_failure; 218 219 data.data[0] = priv->data; 220 if (nft_data_dump(skb, NFTA_CMP_DATA, &data, 221 NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0) 222 goto nla_put_failure; 223 return 0; 224 225 nla_put_failure: 226 return -1; 227 } 228 229 const struct nft_expr_ops nft_cmp_fast_ops = { 230 .type = &nft_cmp_type, 231 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)), 232 .eval = NULL, /* inlined */ 233 .init = nft_cmp_fast_init, 234 .dump = nft_cmp_fast_dump, 235 .offload = nft_cmp_fast_offload, 236 }; 237 238 static const struct nft_expr_ops * 239 nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) 240 { 241 struct nft_data_desc desc; 242 struct nft_data data; 243 enum nft_cmp_ops op; 244 int err; 245 246 if (tb[NFTA_CMP_SREG] == NULL || 247 tb[NFTA_CMP_OP] == NULL || 248 tb[NFTA_CMP_DATA] == NULL) 249 return ERR_PTR(-EINVAL); 250 251 op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 252 switch (op) { 253 case NFT_CMP_EQ: 254 case NFT_CMP_NEQ: 255 case NFT_CMP_LT: 256 case NFT_CMP_LTE: 257 case NFT_CMP_GT: 258 case NFT_CMP_GTE: 259 break; 260 default: 261 return ERR_PTR(-EINVAL); 262 } 263 264 err = nft_data_init(NULL, &data, sizeof(data), &desc, 265 tb[NFTA_CMP_DATA]); 266 if (err < 0) 267 return ERR_PTR(err); 268 269 if (desc.type != NFT_DATA_VALUE) 270 goto err1; 271 272 if (desc.len <= sizeof(u32) && (op == NFT_CMP_EQ || op == NFT_CMP_NEQ)) 273 return &nft_cmp_fast_ops; 274 275 return &nft_cmp_ops; 276 err1: 277 nft_data_release(&data, desc.type); 278 return ERR_PTR(-EINVAL); 279 } 280 281 struct nft_expr_type nft_cmp_type __read_mostly = { 282 .name = "cmp", 283 .select_ops = nft_cmp_select_ops, 284 .policy = nft_cmp_policy, 285 .maxattr = NFTA_CMP_MAX, 286 .owner = THIS_MODULE, 287 }; 288