diff options
Diffstat (limited to 'src/expr/meta.c')
| -rw-r--r-- | src/expr/meta.c | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/src/expr/meta.c b/src/expr/meta.c new file mode 100644 index 0000000..0251e43 --- /dev/null +++ b/src/expr/meta.c @@ -0,0 +1,144 @@ +/* + * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org> + * + * 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. + * + * This code has been sponsored by Sophos Astaro <http://www.sophos.com> + */ + +#include <stdio.h> +#include <stdint.h> +#include <arpa/inet.h> + +#include <linux/netfilter/nf_tables.h> + +#include "internal.h" +#include <libmnl/libmnl.h> +#include <libnftables/expr.h> +#include "expr_ops.h" + +struct nft_expr_meta { + uint8_t key; /* enum nft_meta_keys */ + uint8_t dreg; /* enum nft_registers */ +}; + +static int +nft_rule_expr_meta_set(struct nft_rule_expr *e, uint16_t type, + const void *data, size_t data_len) +{ + struct nft_expr_meta *meta = (struct nft_expr_meta *)e->data; + + switch(type) { + case NFT_EXPR_META_KEY: + meta->key = *((uint32_t *)data); + break; + case NFT_EXPR_META_DREG: + meta->dreg = *((uint32_t *)data); + break; + default: + return -1; + } + return 0; +} + +static const void * +nft_rule_expr_meta_get(struct nft_rule_expr *e, uint16_t type, size_t *data_len) +{ + struct nft_expr_meta *meta = (struct nft_expr_meta *)e->data; + + switch(type) { + case NFT_EXPR_META_KEY: + if (e->flags & (1 << NFT_EXPR_META_KEY)) { + *data_len = sizeof(meta->key); + return &meta->key; + } else + return NULL; + break; + case NFT_EXPR_META_DREG: + if (e->flags & (1 << NFT_EXPR_META_DREG)) { + *data_len = sizeof(meta->dreg); + return &meta->dreg; + } else + return NULL; + break; + default: + break; + } + return NULL; +} + +static int nft_rule_expr_meta_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_META_MAX) < 0) + return MNL_CB_OK; + + switch(type) { + case NFTA_META_KEY: + case NFTA_META_DREG: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) { + perror("mnl_attr_validate"); + return MNL_CB_ERROR; + } + break; + } + + tb[type] = attr; + return MNL_CB_OK; +} + +static void +nft_rule_expr_meta_build(struct nlmsghdr *nlh, struct nft_rule_expr *e) +{ + struct nft_expr_meta *meta = (struct nft_expr_meta *)e->data; + + if (e->flags & (1 << NFT_EXPR_META_KEY)) + mnl_attr_put_u32(nlh, NFTA_META_KEY, htonl(meta->key)); + if (e->flags & (1 << NFT_EXPR_META_DREG)) + mnl_attr_put_u32(nlh, NFTA_META_DREG, htonl(meta->dreg)); +} + +static int +nft_rule_expr_meta_parse(struct nft_rule_expr *e, struct nlattr *attr) +{ + struct nft_expr_meta *meta = (struct nft_expr_meta *)e->data; + struct nlattr *tb[NFTA_META_MAX+1] = {}; + + if (mnl_attr_parse_nested(attr, nft_rule_expr_meta_cb, tb) < 0) + return -1; + + if (tb[NFTA_META_KEY]) { + meta->key = ntohl(mnl_attr_get_u32(tb[NFTA_META_KEY])); + e->flags |= (1 << NFT_EXPR_META_KEY); + } + if (tb[NFTA_META_DREG]) { + meta->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_META_DREG])); + e->flags |= (1 << NFT_EXPR_META_DREG); + } + + return 0; +} + +static int +nft_rule_expr_meta_snprintf(char *buf, size_t len, struct nft_rule_expr *e) +{ + struct nft_expr_meta *meta = (struct nft_expr_meta *)e->data; + + return snprintf(buf, len, "dreg=%u key=%u ", meta->dreg, meta->key); +} + +struct expr_ops expr_ops_meta = { + .name = "meta", + .alloc_len = sizeof(struct nft_expr_meta), + .max_attr = NFTA_META_MAX, + .set = nft_rule_expr_meta_set, + .get = nft_rule_expr_meta_get, + .parse = nft_rule_expr_meta_parse, + .build = nft_rule_expr_meta_build, + .snprintf = nft_rule_expr_meta_snprintf, +}; |