From 00c179b4c9f9f9394cc6f79e5f2a68410631fd72 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Fri, 3 Aug 2012 17:31:48 +0200 Subject: 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 --- src/expr/match.c | 203 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 203 insertions(+) create mode 100644 src/expr/match.c (limited to 'src/expr/match.c') diff --git a/src/expr/match.c b/src/expr/match.c new file mode 100644 index 0000000..a9e2dee --- /dev/null +++ b/src/expr/match.c @@ -0,0 +1,203 @@ +/* + * (C) 2012 by Pablo Neira Ayuso + * + * 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 + */ + +#include "internal.h" + +#include +#include +#include /* for memcpy */ +#include + +#include + +#include +#include + +#include + +#include "expr_ops.h" + +struct nft_expr_match { + char name[XT_EXTENSION_MAXNAMELEN]; + uint32_t rev; + uint32_t data_len; + const void *data; +}; + +static int +nft_rule_expr_match_set(struct nft_rule_expr *e, uint16_t type, + const void *data, size_t data_len) +{ + struct nft_expr_match *mt = (struct nft_expr_match *)e->data; + + switch(type) { + case NFT_EXPR_MT_NAME: + memcpy(mt->name, data, XT_EXTENSION_MAXNAMELEN); + mt->name[XT_EXTENSION_MAXNAMELEN-1] = '\0'; + break; + case NFT_EXPR_MT_REV: + mt->rev = *((uint32_t *)data); + break; + case NFT_EXPR_MT_INFO: + if (mt->data) + free((void *)mt->data); + + mt->data = data; + mt->data_len = data_len; + break; + default: + return -1; + } + return 0; +} + +static const void * +nft_rule_expr_match_get(struct nft_rule_expr *e, uint16_t type, + size_t *data_len) +{ + struct nft_expr_match *mt = (struct nft_expr_match *)e->data; + + switch(type) { + case NFT_EXPR_MT_NAME: + if (e->flags & (1 << NFT_EXPR_MT_NAME)) { + *data_len = sizeof(mt->name); + return mt->name; + } else + return NULL; + break; + case NFT_EXPR_MT_REV: + if (e->flags & (1 << NFT_EXPR_MT_REV)) { + *data_len = sizeof(mt->rev); + return &mt->rev; + } else + return NULL; + break; + case NFT_EXPR_MT_INFO: + if (e->flags & (1 << NFT_EXPR_MT_INFO)) { + *data_len = mt->data_len; + return mt->data; + } else + return NULL; + break; + default: + break; + } + return NULL; +} + +static int nft_rule_expr_match_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_MATCH_MAX) < 0) + return MNL_CB_OK; + + switch(type) { + case NFTA_MATCH_NAME: + if (mnl_attr_validate(attr, MNL_TYPE_NUL_STRING) < 0) { + perror("mnl_attr_validate"); + return MNL_CB_ERROR; + } + break; + case NFTA_MATCH_REV: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) { + perror("mnl_attr_validate"); + return MNL_CB_ERROR; + } + break; + case NFTA_MATCH_INFO: + 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_match_build(struct nlmsghdr *nlh, struct nft_rule_expr *e) +{ + struct nft_expr_match *mt = (struct nft_expr_match *)e->data; + + if (e->flags & (1 << NFT_EXPR_MT_NAME)) + mnl_attr_put_strz(nlh, NFTA_MATCH_NAME, mt->name); + if (e->flags & (1 << NFT_EXPR_MT_REV)) + mnl_attr_put_u32(nlh, NFTA_MATCH_REV, htonl(mt->rev)); + if (e->flags & (1 << NFT_EXPR_MT_INFO)) + mnl_attr_put(nlh, NFTA_MATCH_INFO, XT_ALIGN(mt->data_len), mt->data); +} + +static int nft_rule_expr_match_parse(struct nft_rule_expr *e, struct nlattr *attr) +{ + struct nft_expr_match *match = (struct nft_expr_match *)e->data; + struct nlattr *tb[NFTA_MATCH_MAX+1] = {}; + + if (mnl_attr_parse_nested(attr, nft_rule_expr_match_cb, tb) < 0) + return -1; + + if (tb[NFTA_MATCH_NAME]) { + snprintf(match->name, XT_EXTENSION_MAXNAMELEN, "%s", + mnl_attr_get_str(tb[NFTA_MATCH_NAME])); + + match->name[XT_EXTENSION_MAXNAMELEN-1] = '\0'; + e->flags |= (1 << NFTA_MATCH_NAME); + } + + if (tb[NFTA_MATCH_REV]) { + match->rev = ntohl(mnl_attr_get_u32(tb[NFTA_MATCH_REV])); + e->flags |= (1 << NFTA_MATCH_REV); + } + + if (tb[NFTA_MATCH_INFO]) { + uint32_t len = mnl_attr_get_payload_len(tb[NFTA_MATCH_INFO]); + void *match_data; + + if (match->data) + free((void *) match->data); + + match_data = calloc(1, len); + if (match_data == NULL) + return -1; + + memcpy(match_data, mnl_attr_get_payload(tb[NFTA_MATCH_INFO]), len); + + match->data = match_data; + match->data_len = len; + + e->flags |= (1 << NFTA_MATCH_INFO); + } + + return 0; +} + +static int +nft_rule_expr_match_snprintf(char *buf, size_t len, struct nft_rule_expr *e) +{ + struct nft_expr_match *match = (struct nft_expr_match *)e->data; + + return snprintf(buf, len, "name=%s rev=%u ", + match->name, match->rev); +} + +struct expr_ops expr_ops_match = { + .name = "match", + .alloc_len = sizeof(struct nft_expr_match), + .max_attr = NFTA_MATCH_MAX, + .set = nft_rule_expr_match_set, + .get = nft_rule_expr_match_get, + .parse = nft_rule_expr_match_parse, + .build = nft_rule_expr_match_build, + .snprintf = nft_rule_expr_match_snprintf, +}; -- cgit v1.2.3