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Diffstat (limited to '')
| -rw-r--r-- | src/expr/hash.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/src/expr/hash.c b/src/expr/hash.c new file mode 100644 index 0000000..6e2dd19 --- /dev/null +++ b/src/expr/hash.c @@ -0,0 +1,230 @@ +/* + * (C) 2016 by Laura Garcia <nevola@gmail.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published + * by the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + */ + +#include <stdio.h> +#include <stdint.h> +#include <string.h> +#include <arpa/inet.h> +#include <errno.h> +#include <linux/netfilter/nf_tables.h> + +#include "internal.h" +#include <libmnl/libmnl.h> +#include <libnftnl/expr.h> +#include <libnftnl/rule.h> + +struct nftnl_expr_hash { + enum nft_hash_types type; + enum nft_registers sreg; + enum nft_registers dreg; + unsigned int len; + unsigned int modulus; + unsigned int seed; + unsigned int offset; +}; + +static int +nftnl_expr_hash_set(struct nftnl_expr *e, uint16_t type, + const void *data, uint32_t data_len) +{ + struct nftnl_expr_hash *hash = nftnl_expr_data(e); + switch (type) { + case NFTNL_EXPR_HASH_SREG: + memcpy(&hash->sreg, data, sizeof(hash->sreg)); + break; + case NFTNL_EXPR_HASH_DREG: + memcpy(&hash->dreg, data, sizeof(hash->dreg)); + break; + case NFTNL_EXPR_HASH_LEN: + memcpy(&hash->len, data, sizeof(hash->len)); + break; + case NFTNL_EXPR_HASH_MODULUS: + memcpy(&hash->modulus, data, sizeof(hash->modulus)); + break; + case NFTNL_EXPR_HASH_SEED: + memcpy(&hash->seed, data, sizeof(hash->seed)); + break; + case NFTNL_EXPR_HASH_OFFSET: + memcpy(&hash->offset, data, sizeof(hash->offset)); + break; + case NFTNL_EXPR_HASH_TYPE: + memcpy(&hash->type, data, sizeof(hash->type)); + break; + default: + return -1; + } + return 0; +} + +static const void * +nftnl_expr_hash_get(const struct nftnl_expr *e, uint16_t type, + uint32_t *data_len) +{ + struct nftnl_expr_hash *hash = nftnl_expr_data(e); + + switch (type) { + case NFTNL_EXPR_HASH_SREG: + *data_len = sizeof(hash->sreg); + return &hash->sreg; + case NFTNL_EXPR_HASH_DREG: + *data_len = sizeof(hash->dreg); + return &hash->dreg; + case NFTNL_EXPR_HASH_LEN: + *data_len = sizeof(hash->len); + return &hash->len; + case NFTNL_EXPR_HASH_MODULUS: + *data_len = sizeof(hash->modulus); + return &hash->modulus; + case NFTNL_EXPR_HASH_SEED: + *data_len = sizeof(hash->seed); + return &hash->seed; + case NFTNL_EXPR_HASH_OFFSET: + *data_len = sizeof(hash->offset); + return &hash->offset; + case NFTNL_EXPR_HASH_TYPE: + *data_len = sizeof(hash->type); + return &hash->type; + } + return NULL; +} + +static int nftnl_expr_hash_cb(const struct nlattr *attr, void *data) +{ + const struct nlattr **tb = data; + int type = mnl_attr_get_type(attr); + + if (mnl_attr_type_valid(attr, NFTA_HASH_MAX) < 0) + return MNL_CB_OK; + + switch (type) { + case NFTA_HASH_SREG: + case NFTA_HASH_DREG: + case NFTA_HASH_LEN: + case NFTA_HASH_MODULUS: + case NFTA_HASH_SEED: + case NFTA_HASH_OFFSET: + case NFTA_HASH_TYPE: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) + abi_breakage(); + break; + } + + tb[type] = attr; + return MNL_CB_OK; +} + +static void +nftnl_expr_hash_build(struct nlmsghdr *nlh, const struct nftnl_expr *e) +{ + struct nftnl_expr_hash *hash = nftnl_expr_data(e); + + if (e->flags & (1 << NFTNL_EXPR_HASH_SREG)) + mnl_attr_put_u32(nlh, NFTA_HASH_SREG, htonl(hash->sreg)); + if (e->flags & (1 << NFTNL_EXPR_HASH_DREG)) + mnl_attr_put_u32(nlh, NFTA_HASH_DREG, htonl(hash->dreg)); + if (e->flags & (1 << NFTNL_EXPR_HASH_LEN)) + mnl_attr_put_u32(nlh, NFTA_HASH_LEN, htonl(hash->len)); + if (e->flags & (1 << NFTNL_EXPR_HASH_MODULUS)) + mnl_attr_put_u32(nlh, NFTA_HASH_MODULUS, htonl(hash->modulus)); + if (e->flags & (1 << NFTNL_EXPR_HASH_SEED)) + mnl_attr_put_u32(nlh, NFTA_HASH_SEED, htonl(hash->seed)); + if (e->flags & (1 << NFTNL_EXPR_HASH_OFFSET)) + mnl_attr_put_u32(nlh, NFTA_HASH_OFFSET, htonl(hash->offset)); + if (e->flags & (1 << NFTNL_EXPR_HASH_TYPE)) + mnl_attr_put_u32(nlh, NFTA_HASH_TYPE, htonl(hash->type)); +} + +static int +nftnl_expr_hash_parse(struct nftnl_expr *e, struct nlattr *attr) +{ + struct nftnl_expr_hash *hash = nftnl_expr_data(e); + struct nlattr *tb[NFTA_HASH_MAX+1] = {}; + int ret = 0; + + if (mnl_attr_parse_nested(attr, nftnl_expr_hash_cb, tb) < 0) + return -1; + + if (tb[NFTA_HASH_SREG]) { + hash->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_SREG])); + e->flags |= (1 << NFTNL_EXPR_HASH_SREG); + } + if (tb[NFTA_HASH_DREG]) { + hash->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_DREG])); + e->flags |= (1 << NFTNL_EXPR_HASH_DREG); + } + if (tb[NFTA_HASH_LEN]) { + hash->len = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_LEN])); + e->flags |= (1 << NFTNL_EXPR_HASH_LEN); + } + if (tb[NFTA_HASH_MODULUS]) { + hash->modulus = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_MODULUS])); + e->flags |= (1 << NFTNL_EXPR_HASH_MODULUS); + } + if (tb[NFTA_HASH_SEED]) { + hash->seed = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_SEED])); + e->flags |= (1 << NFTNL_EXPR_HASH_SEED); + } + if (tb[NFTA_HASH_OFFSET]) { + hash->offset = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_OFFSET])); + e->flags |= (1 << NFTNL_EXPR_HASH_OFFSET); + } + if (tb[NFTA_HASH_TYPE]) { + hash->type = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_TYPE])); + e->flags |= (1 << NFTNL_EXPR_HASH_TYPE); + } + + return ret; +} + +static int +nftnl_expr_hash_snprintf(char *buf, size_t remain, + uint32_t flags, const struct nftnl_expr *e) +{ + struct nftnl_expr_hash *hash = nftnl_expr_data(e); + int offset = 0, ret; + + switch (hash->type) { + case NFT_HASH_SYM: + ret = + snprintf(buf, remain, "reg %u = symhash() %% mod %u ", + hash->dreg, + hash->modulus); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + break; + case NFT_HASH_JENKINS: + default: + ret = + snprintf(buf, remain, + "reg %u = jhash(reg %u, %u, 0x%x) %% mod %u ", + hash->dreg, hash->sreg, hash->len, hash->seed, + hash->modulus); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + break; + } + + if (hash->offset) { + ret = snprintf(buf + offset, remain, "offset %u ", + hash->offset); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + } + + return offset; +} + +struct expr_ops expr_ops_hash = { + .name = "hash", + .alloc_len = sizeof(struct nftnl_expr_hash), + .max_attr = NFTA_HASH_MAX, + .set = nftnl_expr_hash_set, + .get = nftnl_expr_hash_get, + .parse = nftnl_expr_hash_parse, + .build = nftnl_expr_hash_build, + .output = nftnl_expr_hash_snprintf, +}; 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