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Diffstat (limited to 'src/expr/immediate.c')
| -rw-r--r-- | src/expr/immediate.c | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/src/expr/immediate.c b/src/expr/immediate.c new file mode 100644 index 0000000..5d477a8 --- /dev/null +++ b/src/expr/immediate.c @@ -0,0 +1,233 @@ +/* + * (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 <errno.h> +#include "internal.h" +#include <libmnl/libmnl.h> +#include <linux/netfilter/nf_tables.h> +#include <libnftnl/expr.h> +#include <libnftnl/rule.h> + +struct nftnl_expr_immediate { + union nftnl_data_reg data; + enum nft_registers dreg; +}; + +static int +nftnl_expr_immediate_set(struct nftnl_expr *e, uint16_t type, + const void *data, uint32_t data_len) +{ + struct nftnl_expr_immediate *imm = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_IMM_DREG: + memcpy(&imm->dreg, data, sizeof(imm->dreg)); + break; + case NFTNL_EXPR_IMM_DATA: + memcpy(&imm->data.val, data, data_len); + imm->data.len = data_len; + break; + case NFTNL_EXPR_IMM_VERDICT: + memcpy(&imm->data.verdict, data, sizeof(imm->data.verdict)); + break; + case NFTNL_EXPR_IMM_CHAIN: + if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN)) + xfree(imm->data.chain); + + imm->data.chain = strdup(data); + if (!imm->data.chain) + return -1; + break; + case NFTNL_EXPR_IMM_CHAIN_ID: + memcpy(&imm->data.chain_id, data, sizeof(uint32_t)); + break; + default: + return -1; + } + return 0; +} + +static const void * +nftnl_expr_immediate_get(const struct nftnl_expr *e, uint16_t type, + uint32_t *data_len) +{ + struct nftnl_expr_immediate *imm = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_IMM_DREG: + *data_len = sizeof(imm->dreg); + return &imm->dreg; + case NFTNL_EXPR_IMM_DATA: + *data_len = imm->data.len; + return &imm->data.val; + case NFTNL_EXPR_IMM_VERDICT: + *data_len = sizeof(imm->data.verdict); + return &imm->data.verdict; + case NFTNL_EXPR_IMM_CHAIN: + *data_len = strlen(imm->data.chain)+1; + return imm->data.chain; + case NFTNL_EXPR_IMM_CHAIN_ID: + *data_len = sizeof(imm->data.chain_id); + return &imm->data.chain_id; + } + return NULL; +} + +static int nftnl_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) + abi_breakage(); + break; + case NFTA_IMMEDIATE_DATA: + if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) + abi_breakage(); + break; + } + + tb[type] = attr; + return MNL_CB_OK; +} + +static void +nftnl_expr_immediate_build(struct nlmsghdr *nlh, const struct nftnl_expr *e) +{ + struct nftnl_expr_immediate *imm = nftnl_expr_data(e); + + if (e->flags & (1 << NFTNL_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 << NFTNL_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 << NFTNL_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 << NFTNL_EXPR_IMM_CHAIN)) + mnl_attr_put_strz(nlh, NFTA_VERDICT_CHAIN, imm->data.chain); + if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN_ID)) { + mnl_attr_put_u32(nlh, NFTA_VERDICT_CHAIN_ID, + htonl(imm->data.chain_id)); + } + + mnl_attr_nest_end(nlh, nest1); + mnl_attr_nest_end(nlh, nest2); + } +} + +static int +nftnl_expr_immediate_parse(struct nftnl_expr *e, struct nlattr *attr) +{ + struct nftnl_expr_immediate *imm = nftnl_expr_data(e); + struct nlattr *tb[NFTA_IMMEDIATE_MAX+1] = {}; + int ret = 0; + + if (mnl_attr_parse_nested(attr, nftnl_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 << NFTNL_EXPR_IMM_DREG); + } + if (tb[NFTA_IMMEDIATE_DATA]) { + int type; + + ret = nftnl_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 << NFTNL_EXPR_IMM_DATA); + break; + case DATA_VERDICT: + /* NF_ACCEPT, NF_DROP, NF_QUEUE and NFTNL_RETURN case */ + e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT); + break; + case DATA_CHAIN: + /* NFTNL_GOTO and NFTNL_JUMP case */ + e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT) | + (1 << NFTNL_EXPR_IMM_CHAIN); + break; + } + } + + return ret; +} + +static int +nftnl_expr_immediate_snprintf(char *buf, size_t remain, + uint32_t flags, const struct nftnl_expr *e) +{ + struct nftnl_expr_immediate *imm = nftnl_expr_data(e); + int offset = 0, ret; + + ret = snprintf(buf, remain, "reg %u ", imm->dreg); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + if (e->flags & (1 << NFTNL_EXPR_IMM_DATA)) { + ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data, + flags, DATA_VALUE); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + } else if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT)) { + ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data, + flags, DATA_VERDICT); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + } else if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN)) { + ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data, + flags, DATA_CHAIN); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + } + + return offset; +} + +static void nftnl_expr_immediate_free(const struct nftnl_expr *e) +{ + struct nftnl_expr_immediate *imm = nftnl_expr_data(e); + + if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT)) + nftnl_free_verdict(&imm->data); +} + +struct expr_ops expr_ops_immediate = { + .name = "immediate", + .alloc_len = sizeof(struct nftnl_expr_immediate), + .max_attr = NFTA_IMMEDIATE_MAX, + .free = nftnl_expr_immediate_free, + .set = nftnl_expr_immediate_set, + .get = nftnl_expr_immediate_get, + .parse = nftnl_expr_immediate_parse, + .build = nftnl_expr_immediate_build, + .output = nftnl_expr_immediate_snprintf, +}; 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