diff options
Diffstat (limited to 'src/expr/match.c')
| -rw-r--r-- | src/expr/match.c | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/src/expr/match.c b/src/expr/match.c new file mode 100644 index 0000000..f472add --- /dev/null +++ b/src/expr/match.c @@ -0,0 +1,193 @@ +/* + * (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 "internal.h" + +#include <stdio.h> +#include <stdint.h> +#include <string.h> /* for memcpy */ +#include <arpa/inet.h> +#include <errno.h> +#include <libmnl/libmnl.h> + +#include <linux/netfilter/nf_tables.h> +#include <linux/netfilter/nf_tables_compat.h> + +#include <libnftnl/expr.h> +#include <libnftnl/rule.h> + +/* From include/linux/netfilter/x_tables.h */ +#define XT_EXTENSION_MAXNAMELEN 29 + +struct nftnl_expr_match { + char name[XT_EXTENSION_MAXNAMELEN]; + uint32_t rev; + uint32_t data_len; + const void *data; +}; + +static int +nftnl_expr_match_set(struct nftnl_expr *e, uint16_t type, + const void *data, uint32_t data_len) +{ + struct nftnl_expr_match *mt = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_MT_NAME: + snprintf(mt->name, sizeof(mt->name), "%.*s", data_len, + (const char *)data); + break; + case NFTNL_EXPR_MT_REV: + memcpy(&mt->rev, data, sizeof(mt->rev)); + break; + case NFTNL_EXPR_MT_INFO: + if (e->flags & (1 << NFTNL_EXPR_MT_INFO)) + xfree(mt->data); + + mt->data = data; + mt->data_len = data_len; + break; + default: + return -1; + } + return 0; +} + +static const void * +nftnl_expr_match_get(const struct nftnl_expr *e, uint16_t type, + uint32_t *data_len) +{ + struct nftnl_expr_match *mt = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_MT_NAME: + *data_len = sizeof(mt->name); + return mt->name; + case NFTNL_EXPR_MT_REV: + *data_len = sizeof(mt->rev); + return &mt->rev; + case NFTNL_EXPR_MT_INFO: + *data_len = mt->data_len; + return mt->data; + } + return NULL; +} + +static int nftnl_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) + abi_breakage(); + break; + case NFTA_MATCH_REV: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) + abi_breakage(); + break; + case NFTA_MATCH_INFO: + if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) + abi_breakage(); + break; + } + + tb[type] = attr; + return MNL_CB_OK; +} + +static void +nftnl_expr_match_build(struct nlmsghdr *nlh, const struct nftnl_expr *e) +{ + struct nftnl_expr_match *mt = nftnl_expr_data(e); + + if (e->flags & (1 << NFTNL_EXPR_MT_NAME)) + mnl_attr_put_strz(nlh, NFTA_MATCH_NAME, mt->name); + if (e->flags & (1 << NFTNL_EXPR_MT_REV)) + mnl_attr_put_u32(nlh, NFTA_MATCH_REV, htonl(mt->rev)); + if (e->flags & (1 << NFTNL_EXPR_MT_INFO)) + mnl_attr_put(nlh, NFTA_MATCH_INFO, mt->data_len, mt->data); +} + +static int nftnl_expr_match_parse(struct nftnl_expr *e, struct nlattr *attr) +{ + struct nftnl_expr_match *match = nftnl_expr_data(e); + struct nlattr *tb[NFTA_MATCH_MAX+1] = {}; + + if (mnl_attr_parse_nested(attr, nftnl_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 << NFTNL_EXPR_MT_NAME); + } + + if (tb[NFTA_MATCH_REV]) { + match->rev = ntohl(mnl_attr_get_u32(tb[NFTA_MATCH_REV])); + e->flags |= (1 << NFTNL_EXPR_MT_REV); + } + + if (tb[NFTA_MATCH_INFO]) { + uint32_t len = mnl_attr_get_payload_len(tb[NFTA_MATCH_INFO]); + void *match_data; + + if (e->flags & (1 << NFTNL_EXPR_MT_INFO)) + xfree(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 << NFTNL_EXPR_MT_INFO); + } + + return 0; +} + +static int +nftnl_expr_match_snprintf(char *buf, size_t len, + uint32_t flags, const struct nftnl_expr *e) +{ + struct nftnl_expr_match *match = nftnl_expr_data(e); + + return snprintf(buf, len, "name %s rev %u ", match->name, match->rev); +} + +static void nftnl_expr_match_free(const struct nftnl_expr *e) +{ + struct nftnl_expr_match *match = nftnl_expr_data(e); + + xfree(match->data); +} + +struct expr_ops expr_ops_match = { + .name = "match", + .alloc_len = sizeof(struct nftnl_expr_match), + .max_attr = NFTA_MATCH_MAX, + .free = nftnl_expr_match_free, + .set = nftnl_expr_match_set, + .get = nftnl_expr_match_get, + .parse = nftnl_expr_match_parse, + .build = nftnl_expr_match_build, + .output = nftnl_expr_match_snprintf, +}; |