diff options
Diffstat (limited to 'src/expr/target.c')
| -rw-r--r-- | src/expr/target.c | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/src/expr/target.c b/src/expr/target.c new file mode 100644 index 0000000..2a3fe8a --- /dev/null +++ b/src/expr/target.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_target { + char name[XT_EXTENSION_MAXNAMELEN]; + uint32_t rev; + uint32_t data_len; + const void *data; +}; + +static int +nftnl_expr_target_set(struct nftnl_expr *e, uint16_t type, + const void *data, uint32_t data_len) +{ + struct nftnl_expr_target *tg = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_TG_NAME: + snprintf(tg->name, sizeof(tg->name), "%.*s", data_len, + (const char *) data); + break; + case NFTNL_EXPR_TG_REV: + memcpy(&tg->rev, data, sizeof(tg->rev)); + break; + case NFTNL_EXPR_TG_INFO: + if (e->flags & (1 << NFTNL_EXPR_TG_INFO)) + xfree(tg->data); + + tg->data = data; + tg->data_len = data_len; + break; + default: + return -1; + } + return 0; +} + +static const void * +nftnl_expr_target_get(const struct nftnl_expr *e, uint16_t type, + uint32_t *data_len) +{ + struct nftnl_expr_target *tg = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_TG_NAME: + *data_len = sizeof(tg->name); + return tg->name; + case NFTNL_EXPR_TG_REV: + *data_len = sizeof(tg->rev); + return &tg->rev; + case NFTNL_EXPR_TG_INFO: + *data_len = tg->data_len; + return tg->data; + } + return NULL; +} + +static int nftnl_expr_target_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_TARGET_MAX) < 0) + return MNL_CB_OK; + + switch(type) { + case NFTA_TARGET_NAME: + if (mnl_attr_validate(attr, MNL_TYPE_NUL_STRING) < 0) + abi_breakage(); + break; + case NFTA_TARGET_REV: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) + abi_breakage(); + break; + case NFTA_TARGET_INFO: + if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) + abi_breakage(); + break; + } + + tb[type] = attr; + return MNL_CB_OK; +} + +static void +nftnl_expr_target_build(struct nlmsghdr *nlh, const struct nftnl_expr *e) +{ + struct nftnl_expr_target *tg = nftnl_expr_data(e); + + if (e->flags & (1 << NFTNL_EXPR_TG_NAME)) + mnl_attr_put_strz(nlh, NFTA_TARGET_NAME, tg->name); + if (e->flags & (1 << NFTNL_EXPR_TG_REV)) + mnl_attr_put_u32(nlh, NFTA_TARGET_REV, htonl(tg->rev)); + if (e->flags & (1 << NFTNL_EXPR_TG_INFO)) + mnl_attr_put(nlh, NFTA_TARGET_INFO, tg->data_len, tg->data); +} + +static int nftnl_expr_target_parse(struct nftnl_expr *e, struct nlattr *attr) +{ + struct nftnl_expr_target *target = nftnl_expr_data(e); + struct nlattr *tb[NFTA_TARGET_MAX+1] = {}; + + if (mnl_attr_parse_nested(attr, nftnl_expr_target_cb, tb) < 0) + return -1; + + if (tb[NFTA_TARGET_NAME]) { + snprintf(target->name, XT_EXTENSION_MAXNAMELEN, "%s", + mnl_attr_get_str(tb[NFTA_TARGET_NAME])); + + target->name[XT_EXTENSION_MAXNAMELEN-1] = '\0'; + e->flags |= (1 << NFTNL_EXPR_TG_NAME); + } + + if (tb[NFTA_TARGET_REV]) { + target->rev = ntohl(mnl_attr_get_u32(tb[NFTA_TARGET_REV])); + e->flags |= (1 << NFTNL_EXPR_TG_REV); + } + + if (tb[NFTA_TARGET_INFO]) { + uint32_t len = mnl_attr_get_payload_len(tb[NFTA_TARGET_INFO]); + void *target_data; + + if (target->data) + xfree(target->data); + + target_data = calloc(1, len); + if (target_data == NULL) + return -1; + + memcpy(target_data, mnl_attr_get_payload(tb[NFTA_TARGET_INFO]), len); + + target->data = target_data; + target->data_len = len; + + e->flags |= (1 << NFTNL_EXPR_TG_INFO); + } + + return 0; +} + +static int +nftnl_expr_target_snprintf(char *buf, size_t len, + uint32_t flags, const struct nftnl_expr *e) +{ + struct nftnl_expr_target *target = nftnl_expr_data(e); + + return snprintf(buf, len, "name %s rev %u ", target->name, target->rev); +} + +static void nftnl_expr_target_free(const struct nftnl_expr *e) +{ + struct nftnl_expr_target *target = nftnl_expr_data(e); + + xfree(target->data); +} + +struct expr_ops expr_ops_target = { + .name = "target", + .alloc_len = sizeof(struct nftnl_expr_target), + .max_attr = NFTA_TARGET_MAX, + .free = nftnl_expr_target_free, + .set = nftnl_expr_target_set, + .get = nftnl_expr_target_get, + .parse = nftnl_expr_target_parse, + .build = nftnl_expr_target_build, + .output = nftnl_expr_target_snprintf, +}; |