diff options
Diffstat (limited to 'net/netfilter/nft_cmp.c')
-rw-r--r-- | net/netfilter/nft_cmp.c | 433 |
1 files changed, 433 insertions, 0 deletions
diff --git a/net/netfilter/nft_cmp.c b/net/netfilter/nft_cmp.c new file mode 100644 index 000000000..963cf8317 --- /dev/null +++ b/net/netfilter/nft_cmp.c @@ -0,0 +1,433 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> + * + * Development of this code funded by Astaro AG (http://www.astaro.com/) + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/netlink.h> +#include <linux/netfilter.h> +#include <linux/if_arp.h> +#include <linux/netfilter/nf_tables.h> +#include <net/netfilter/nf_tables_core.h> +#include <net/netfilter/nf_tables_offload.h> +#include <net/netfilter/nf_tables.h> + +struct nft_cmp_expr { + struct nft_data data; + u8 sreg; + u8 len; + enum nft_cmp_ops op:8; +}; + +void nft_cmp_eval(const struct nft_expr *expr, + struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + const struct nft_cmp_expr *priv = nft_expr_priv(expr); + int d; + + d = memcmp(®s->data[priv->sreg], &priv->data, priv->len); + switch (priv->op) { + case NFT_CMP_EQ: + if (d != 0) + goto mismatch; + break; + case NFT_CMP_NEQ: + if (d == 0) + goto mismatch; + break; + case NFT_CMP_LT: + if (d == 0) + goto mismatch; + fallthrough; + case NFT_CMP_LTE: + if (d > 0) + goto mismatch; + break; + case NFT_CMP_GT: + if (d == 0) + goto mismatch; + fallthrough; + case NFT_CMP_GTE: + if (d < 0) + goto mismatch; + break; + } + return; + +mismatch: + regs->verdict.code = NFT_BREAK; +} + +static const struct nla_policy nft_cmp_policy[NFTA_CMP_MAX + 1] = { + [NFTA_CMP_SREG] = { .type = NLA_U32 }, + [NFTA_CMP_OP] = { .type = NLA_U32 }, + [NFTA_CMP_DATA] = { .type = NLA_NESTED }, +}; + +static int nft_cmp_init(const struct nft_ctx *ctx, const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_cmp_expr *priv = nft_expr_priv(expr); + struct nft_data_desc desc = { + .type = NFT_DATA_VALUE, + .size = sizeof(priv->data), + }; + int err; + + err = nft_data_init(NULL, &priv->data, &desc, tb[NFTA_CMP_DATA]); + if (err < 0) + return err; + + err = nft_parse_register_load(tb[NFTA_CMP_SREG], &priv->sreg, desc.len); + if (err < 0) + return err; + + priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); + priv->len = desc.len; + return 0; +} + +static int nft_cmp_dump(struct sk_buff *skb, const struct nft_expr *expr) +{ + const struct nft_cmp_expr *priv = nft_expr_priv(expr); + + if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) + goto nla_put_failure; + if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op))) + goto nla_put_failure; + + if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data, + NFT_DATA_VALUE, priv->len) < 0) + goto nla_put_failure; + return 0; + +nla_put_failure: + return -1; +} + +union nft_cmp_offload_data { + u16 val16; + u32 val32; + u64 val64; +}; + +static void nft_payload_n2h(union nft_cmp_offload_data *data, + const u8 *val, u32 len) +{ + switch (len) { + case 2: + data->val16 = ntohs(*((__be16 *)val)); + break; + case 4: + data->val32 = ntohl(*((__be32 *)val)); + break; + case 8: + data->val64 = be64_to_cpu(*((__be64 *)val)); + break; + default: + WARN_ON_ONCE(1); + break; + } +} + +static int __nft_cmp_offload(struct nft_offload_ctx *ctx, + struct nft_flow_rule *flow, + const struct nft_cmp_expr *priv) +{ + struct nft_offload_reg *reg = &ctx->regs[priv->sreg]; + union nft_cmp_offload_data _data, _datamask; + u8 *mask = (u8 *)&flow->match.mask; + u8 *key = (u8 *)&flow->match.key; + u8 *data, *datamask; + + if (priv->op != NFT_CMP_EQ || priv->len > reg->len) + return -EOPNOTSUPP; + + if (reg->flags & NFT_OFFLOAD_F_NETWORK2HOST) { + nft_payload_n2h(&_data, (u8 *)&priv->data, reg->len); + nft_payload_n2h(&_datamask, (u8 *)®->mask, reg->len); + data = (u8 *)&_data; + datamask = (u8 *)&_datamask; + } else { + data = (u8 *)&priv->data; + datamask = (u8 *)®->mask; + } + + memcpy(key + reg->offset, data, reg->len); + memcpy(mask + reg->offset, datamask, reg->len); + + flow->match.dissector.used_keys |= BIT(reg->key); + flow->match.dissector.offset[reg->key] = reg->base_offset; + + if (reg->key == FLOW_DISSECTOR_KEY_META && + reg->offset == offsetof(struct nft_flow_key, meta.ingress_iftype) && + nft_reg_load16(priv->data.data) != ARPHRD_ETHER) + return -EOPNOTSUPP; + + nft_offload_update_dependency(ctx, &priv->data, reg->len); + + return 0; +} + +static int nft_cmp_offload(struct nft_offload_ctx *ctx, + struct nft_flow_rule *flow, + const struct nft_expr *expr) +{ + const struct nft_cmp_expr *priv = nft_expr_priv(expr); + + return __nft_cmp_offload(ctx, flow, priv); +} + +static const struct nft_expr_ops nft_cmp_ops = { + .type = &nft_cmp_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)), + .eval = nft_cmp_eval, + .init = nft_cmp_init, + .dump = nft_cmp_dump, + .reduce = NFT_REDUCE_READONLY, + .offload = nft_cmp_offload, +}; + +/* Calculate the mask for the nft_cmp_fast expression. On big endian the + * mask needs to include the *upper* bytes when interpreting that data as + * something smaller than the full u32, therefore a cpu_to_le32 is done. + */ +static u32 nft_cmp_fast_mask(unsigned int len) +{ + __le32 mask = cpu_to_le32(~0U >> (sizeof_field(struct nft_cmp_fast_expr, + data) * BITS_PER_BYTE - len)); + + return (__force u32)mask; +} + +static int nft_cmp_fast_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); + struct nft_data data; + struct nft_data_desc desc = { + .type = NFT_DATA_VALUE, + .size = sizeof(data), + }; + int err; + + err = nft_data_init(NULL, &data, &desc, tb[NFTA_CMP_DATA]); + if (err < 0) + return err; + + err = nft_parse_register_load(tb[NFTA_CMP_SREG], &priv->sreg, desc.len); + if (err < 0) + return err; + + desc.len *= BITS_PER_BYTE; + + priv->mask = nft_cmp_fast_mask(desc.len); + priv->data = data.data[0] & priv->mask; + priv->len = desc.len; + priv->inv = ntohl(nla_get_be32(tb[NFTA_CMP_OP])) != NFT_CMP_EQ; + return 0; +} + +static int nft_cmp_fast_offload(struct nft_offload_ctx *ctx, + struct nft_flow_rule *flow, + const struct nft_expr *expr) +{ + const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); + struct nft_cmp_expr cmp = { + .data = { + .data = { + [0] = priv->data, + }, + }, + .sreg = priv->sreg, + .len = priv->len / BITS_PER_BYTE, + .op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ, + }; + + return __nft_cmp_offload(ctx, flow, &cmp); +} + +static int nft_cmp_fast_dump(struct sk_buff *skb, const struct nft_expr *expr) +{ + const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); + enum nft_cmp_ops op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ; + struct nft_data data; + + if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) + goto nla_put_failure; + if (nla_put_be32(skb, NFTA_CMP_OP, htonl(op))) + goto nla_put_failure; + + data.data[0] = priv->data; + if (nft_data_dump(skb, NFTA_CMP_DATA, &data, + NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0) + goto nla_put_failure; + return 0; + +nla_put_failure: + return -1; +} + +const struct nft_expr_ops nft_cmp_fast_ops = { + .type = &nft_cmp_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)), + .eval = NULL, /* inlined */ + .init = nft_cmp_fast_init, + .dump = nft_cmp_fast_dump, + .reduce = NFT_REDUCE_READONLY, + .offload = nft_cmp_fast_offload, +}; + +static u32 nft_cmp_mask(u32 bitlen) +{ + return (__force u32)cpu_to_le32(~0U >> (sizeof(u32) * BITS_PER_BYTE - bitlen)); +} + +static void nft_cmp16_fast_mask(struct nft_data *data, unsigned int bitlen) +{ + int len = bitlen / BITS_PER_BYTE; + int i, words = len / sizeof(u32); + + for (i = 0; i < words; i++) { + data->data[i] = 0xffffffff; + bitlen -= sizeof(u32) * BITS_PER_BYTE; + } + + if (len % sizeof(u32)) + data->data[i++] = nft_cmp_mask(bitlen); + + for (; i < 4; i++) + data->data[i] = 0; +} + +static int nft_cmp16_fast_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr); + struct nft_data_desc desc = { + .type = NFT_DATA_VALUE, + .size = sizeof(priv->data), + }; + int err; + + err = nft_data_init(NULL, &priv->data, &desc, tb[NFTA_CMP_DATA]); + if (err < 0) + return err; + + err = nft_parse_register_load(tb[NFTA_CMP_SREG], &priv->sreg, desc.len); + if (err < 0) + return err; + + nft_cmp16_fast_mask(&priv->mask, desc.len * BITS_PER_BYTE); + priv->inv = ntohl(nla_get_be32(tb[NFTA_CMP_OP])) != NFT_CMP_EQ; + priv->len = desc.len; + + return 0; +} + +static int nft_cmp16_fast_offload(struct nft_offload_ctx *ctx, + struct nft_flow_rule *flow, + const struct nft_expr *expr) +{ + const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr); + struct nft_cmp_expr cmp = { + .data = priv->data, + .sreg = priv->sreg, + .len = priv->len, + .op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ, + }; + + return __nft_cmp_offload(ctx, flow, &cmp); +} + +static int nft_cmp16_fast_dump(struct sk_buff *skb, const struct nft_expr *expr) +{ + const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr); + enum nft_cmp_ops op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ; + + if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) + goto nla_put_failure; + if (nla_put_be32(skb, NFTA_CMP_OP, htonl(op))) + goto nla_put_failure; + + if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data, + NFT_DATA_VALUE, priv->len) < 0) + goto nla_put_failure; + return 0; + +nla_put_failure: + return -1; +} + + +const struct nft_expr_ops nft_cmp16_fast_ops = { + .type = &nft_cmp_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp16_fast_expr)), + .eval = NULL, /* inlined */ + .init = nft_cmp16_fast_init, + .dump = nft_cmp16_fast_dump, + .reduce = NFT_REDUCE_READONLY, + .offload = nft_cmp16_fast_offload, +}; + +static const struct nft_expr_ops * +nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) +{ + struct nft_data data; + struct nft_data_desc desc = { + .type = NFT_DATA_VALUE, + .size = sizeof(data), + }; + enum nft_cmp_ops op; + u8 sreg; + int err; + + if (tb[NFTA_CMP_SREG] == NULL || + tb[NFTA_CMP_OP] == NULL || + tb[NFTA_CMP_DATA] == NULL) + return ERR_PTR(-EINVAL); + + op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); + switch (op) { + case NFT_CMP_EQ: + case NFT_CMP_NEQ: + case NFT_CMP_LT: + case NFT_CMP_LTE: + case NFT_CMP_GT: + case NFT_CMP_GTE: + break; + default: + return ERR_PTR(-EINVAL); + } + + err = nft_data_init(NULL, &data, &desc, tb[NFTA_CMP_DATA]); + if (err < 0) + return ERR_PTR(err); + + sreg = ntohl(nla_get_be32(tb[NFTA_CMP_SREG])); + + if (op == NFT_CMP_EQ || op == NFT_CMP_NEQ) { + if (desc.len <= sizeof(u32)) + return &nft_cmp_fast_ops; + else if (desc.len <= sizeof(data) && + ((sreg >= NFT_REG_1 && sreg <= NFT_REG_4) || + (sreg >= NFT_REG32_00 && sreg <= NFT_REG32_12 && sreg % 2 == 0))) + return &nft_cmp16_fast_ops; + } + return &nft_cmp_ops; +} + +struct nft_expr_type nft_cmp_type __read_mostly = { + .name = "cmp", + .select_ops = nft_cmp_select_ops, + .policy = nft_cmp_policy, + .maxattr = NFTA_CMP_MAX, + .owner = THIS_MODULE, +}; |