diff options
author | Pablo Neira Ayuso <pablo@netfilter.org> | 2012-08-03 17:31:48 +0200 |
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committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2012-10-11 15:15:02 +0200 |
commit | 00c179b4c9f9f9394cc6f79e5f2a68410631fd72 (patch) | |
tree | 00057636d125f3c89e2b9485c67c4283a98d91b2 /src/expr/immediate.c |
initial version of libnftables
It adds support for table, chain and rule handling.
This also includes expression handling for each rule.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'src/expr/immediate.c')
-rw-r--r-- | src/expr/immediate.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/src/expr/immediate.c b/src/expr/immediate.c new file mode 100644 index 0000000..68c27ec --- /dev/null +++ b/src/expr/immediate.c @@ -0,0 +1,215 @@ +/* + * (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 <string.h> +#include <arpa/inet.h> + +#include "internal.h" +#include <libmnl/libmnl.h> +#include <linux/netfilter/nf_tables.h> +#include <libnftables/expr.h> +#include "expr_ops.h" +#include "data_reg.h" + +struct nft_expr_immediate { + union nft_data_reg data; + enum nft_registers dreg; +}; + +static int +nft_rule_expr_immediate_set(struct nft_rule_expr *e, uint16_t type, + const void *data, size_t data_len) +{ + struct nft_expr_immediate *imm = (struct nft_expr_immediate *)e->data; + + switch(type) { + case NFT_EXPR_IMM_DREG: + imm->dreg = *((uint32_t *)data); + break; + case NFT_EXPR_IMM_DATA: + memcpy(&imm->data.val, data, data_len); + imm->data.len = data_len; + break; + case NFT_EXPR_IMM_VERDICT: + imm->data.verdict = *((uint32_t *)data); + break; + case NFT_EXPR_IMM_CHAIN: + if (imm->data.chain) + free(imm->data.chain); + + imm->data.chain = strdup(data); + break; + default: + return -1; + } + return 0; +} + +static const void * +nft_rule_expr_immediate_get(struct nft_rule_expr *e, uint16_t type, + size_t *data_len) +{ + struct nft_expr_immediate *imm = (struct nft_expr_immediate *)e->data; + + switch(type) { + case NFT_EXPR_IMM_DREG: + if (e->flags & (1 << NFT_EXPR_IMM_DREG)) { + *data_len = sizeof(imm->dreg); + return &imm->dreg; + } else + return NULL; + break; + case NFT_EXPR_IMM_DATA: + if (e->flags & (1 << NFT_EXPR_IMM_DATA)) { + *data_len = imm->data.len; + return &imm->data.val; + } else + return NULL; + break; + case NFT_EXPR_IMM_VERDICT: + if (e->flags & (1 << NFT_EXPR_IMM_VERDICT)) { + *data_len = sizeof(imm->data.verdict); + return &imm->data.verdict; + } else + return NULL; + break; + case NFT_EXPR_IMM_CHAIN: + if (e->flags & (1 << NFT_EXPR_IMM_CHAIN)) { + *data_len = strlen(imm->data.chain)+1; + return imm->data.chain; + } else + return NULL; + break; + default: + break; + } + return NULL; +} + +static int nft_rule_expr_immediate_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_IMMEDIATE_MAX) < 0) + return MNL_CB_OK; + + switch(type) { + case NFTA_IMMEDIATE_DREG: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) { + perror("mnl_attr_validate"); + return MNL_CB_ERROR; + } + break; + case NFTA_IMMEDIATE_DATA: + if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) { + perror("mnl_attr_validate"); + return MNL_CB_ERROR; + } + break; + } + + tb[type] = attr; + return MNL_CB_OK; +} + +static void +nft_rule_expr_immediate_build(struct nlmsghdr *nlh, struct nft_rule_expr *e) +{ + struct nft_expr_immediate *imm = (struct nft_expr_immediate *)e->data; + + if (e->flags & (1 << NFT_EXPR_IMM_DREG)) + mnl_attr_put_u32(nlh, NFTA_IMMEDIATE_DREG, htonl(imm->dreg)); + + /* Sane configurations allows you to set ONLY one of these two below */ + if (e->flags & (1 << NFT_EXPR_IMM_DATA)) { + struct nlattr *nest; + + nest = mnl_attr_nest_start(nlh, NFTA_IMMEDIATE_DATA); + mnl_attr_put(nlh, NFTA_DATA_VALUE, imm->data.len, imm->data.val); + mnl_attr_nest_end(nlh, nest); + + } else if (e->flags & (1 << NFT_EXPR_IMM_VERDICT)) { + struct nlattr *nest1, *nest2; + + nest1 = mnl_attr_nest_start(nlh, NFTA_IMMEDIATE_DATA); + nest2 = mnl_attr_nest_start(nlh, NFTA_DATA_VERDICT); + mnl_attr_put_u32(nlh, NFTA_VERDICT_CODE, htonl(imm->data.verdict)); + if (e->flags & (1 << NFT_EXPR_IMM_CHAIN)) + mnl_attr_put_strz(nlh, NFTA_VERDICT_CHAIN, imm->data.chain); + + mnl_attr_nest_end(nlh, nest1); + mnl_attr_nest_end(nlh, nest2); + } +} + +static int +nft_rule_expr_immediate_parse(struct nft_rule_expr *e, struct nlattr *attr) +{ + struct nft_expr_immediate *imm = (struct nft_expr_immediate *)e->data; + struct nlattr *tb[NFTA_IMMEDIATE_MAX+1] = {}; + int ret = 0; + + if (mnl_attr_parse_nested(attr, nft_rule_expr_immediate_cb, tb) < 0) + return -1; + + if (tb[NFTA_IMMEDIATE_DREG]) { + imm->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_IMMEDIATE_DREG])); + e->flags |= (1 << NFT_EXPR_IMM_DREG); + } + if (tb[NFTA_IMMEDIATE_DATA]) { + int type; + + ret = nft_parse_data(&imm->data, tb[NFTA_IMMEDIATE_DATA], &type); + if (ret < 0) + return ret; + + switch(type) { + case DATA_VALUE: + /* real immediate data to be loaded to destination */ + e->flags |= (1 << NFT_EXPR_IMM_DATA); + break; + case DATA_VERDICT: + /* NF_ACCEPT, NF_DROP, NF_QUEUE and NFT_RETURN case */ + e->flags |= (1 << NFT_EXPR_IMM_VERDICT); + break; + case DATA_CHAIN: + /* NFT_GOTO and NFT_JUMP case */ + e->flags |= (1 << NFT_EXPR_IMM_VERDICT) | + (1 << NFT_EXPR_IMM_CHAIN); + break; + } + } + + return ret; +} + +static int +nft_rule_expr_immediate_snprintf(char *buf, size_t len, struct nft_rule_expr *e) +{ + struct nft_expr_immediate *imm = (struct nft_expr_immediate *)e->data; + + return snprintf(buf, len, "dreg=%u data=%u ", + imm->dreg, imm->data.val[0]); +} + +struct expr_ops expr_ops_immediate = { + .name = "immediate", + .alloc_len = sizeof(struct nft_expr_immediate), + .max_attr = NFTA_IMMEDIATE_MAX, + .set = nft_rule_expr_immediate_set, + .get = nft_rule_expr_immediate_get, + .parse = nft_rule_expr_immediate_parse, + .build = nft_rule_expr_immediate_build, + .snprintf = nft_rule_expr_immediate_snprintf, +}; |