summaryrefslogtreecommitdiffstats
path: root/src/rule.c
diff options
context:
space:
mode:
authorPablo Neira Ayuso <pablo@netfilter.org>2012-08-03 17:31:48 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2012-10-11 15:15:02 +0200
commit00c179b4c9f9f9394cc6f79e5f2a68410631fd72 (patch)
tree00057636d125f3c89e2b9485c67c4283a98d91b2 /src/rule.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/rule.c')
-rw-r--r--src/rule.c452
1 files changed, 452 insertions, 0 deletions
diff --git a/src/rule.c b/src/rule.c
new file mode 100644
index 0000000..b0f7bb3
--- /dev/null
+++ b/src/rule.c
@@ -0,0 +1,452 @@
+/*
+ * (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 <time.h>
+#include <endian.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <netinet/in.h>
+
+#include <libmnl/libmnl.h>
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nf_tables.h>
+
+#include <libnftables/rule.h>
+#include <libnftables/expr.h>
+
+#include "linux_list.h"
+#include "expr_ops.h"
+
+struct nft_rule {
+ struct list_head head;
+
+ uint32_t flags;
+ char *table;
+ char *chain;
+ uint8_t family;
+ uint16_t handle;
+
+ struct list_head expr_list;
+};
+
+struct nft_rule *nft_rule_alloc(void)
+{
+ struct nft_rule *r;
+
+ r = calloc(1, sizeof(struct nft_rule));
+ if (r == NULL)
+ return NULL;
+
+ INIT_LIST_HEAD(&r->expr_list);
+
+ return r;
+}
+EXPORT_SYMBOL(nft_rule_alloc);
+
+void nft_rule_free(struct nft_rule *r)
+{
+ if (r->table != NULL)
+ free(r->table);
+ if (r->chain != NULL)
+ free(r->chain);
+
+ free(r);
+}
+EXPORT_SYMBOL(nft_rule_free);
+
+void nft_rule_attr_set(struct nft_rule *r, uint16_t attr, void *data)
+{
+ switch(attr) {
+ case NFT_RULE_ATTR_TABLE:
+ if (r->table)
+ free(r->table);
+
+ r->table = strdup(data);
+ break;
+ case NFT_RULE_ATTR_CHAIN:
+ if (r->chain)
+ free(r->chain);
+
+ r->chain = strdup(data);
+ break;
+ case NFT_RULE_ATTR_HANDLE:
+ r->handle = *((uint16_t *)data);
+ break;
+ default:
+ return;
+ }
+ r->flags |= (1 << attr);
+}
+EXPORT_SYMBOL(nft_rule_attr_set);
+
+void nft_rule_attr_set_u16(struct nft_rule *r, uint16_t attr, uint16_t val)
+{
+ nft_rule_attr_set(r, attr, &val);
+}
+EXPORT_SYMBOL(nft_rule_attr_set_u16);
+
+void nft_rule_attr_set_str(struct nft_rule *r, uint16_t attr, char *str)
+{
+ nft_rule_attr_set(r, attr, str);
+}
+EXPORT_SYMBOL(nft_rule_attr_set_str);
+
+void *nft_rule_attr_get(struct nft_rule *r, uint16_t attr)
+{
+ switch(attr) {
+ case NFT_RULE_ATTR_TABLE:
+ if (r->flags & (1 << NFT_RULE_ATTR_TABLE))
+ return r->table;
+ else
+ return NULL;
+ break;
+ case NFT_RULE_ATTR_CHAIN:
+ if (r->flags & (1 << NFT_RULE_ATTR_CHAIN))
+ return r->chain;
+ else
+ return NULL;
+ case NFT_RULE_ATTR_HANDLE:
+ if (r->flags & (1 << NFT_RULE_ATTR_HANDLE))
+ return &r->handle;
+ else
+ return NULL;
+ break;
+ default:
+ return NULL;
+ }
+}
+EXPORT_SYMBOL(nft_rule_attr_get);
+
+const char *nft_rule_attr_get_str(struct nft_rule *r, uint16_t attr)
+{
+ return nft_rule_attr_get(r, attr);
+}
+EXPORT_SYMBOL(nft_rule_attr_get_str);
+
+uint16_t nft_rule_attr_get_u16(struct nft_rule *r, uint16_t attr)
+{
+ uint16_t val = *((uint32_t *)nft_rule_attr_get(r, attr));
+ return val;
+}
+EXPORT_SYMBOL(nft_rule_attr_get_u16);
+
+struct nlmsghdr *
+nft_rule_nlmsg_build_hdr(char *buf, uint16_t cmd, uint16_t family,
+ uint16_t type, uint32_t seq)
+{
+ struct nlmsghdr *nlh;
+ struct nfgenmsg *nfh;
+
+ nlh = mnl_nlmsg_put_header(buf);
+ nlh->nlmsg_type = (NFNL_SUBSYS_NFTABLES << 8) | cmd;
+ nlh->nlmsg_flags = NLM_F_REQUEST | type;
+ nlh->nlmsg_seq = seq;
+
+ nfh = mnl_nlmsg_put_extra_header(nlh, sizeof(struct nfgenmsg));
+ nfh->nfgen_family = family;
+ nfh->version = NFNETLINK_V0;
+ nfh->res_id = 0;
+
+ return nlh;
+}
+EXPORT_SYMBOL(nft_rule_nlmsg_build_hdr);
+
+void nft_rule_nlmsg_build_payload(struct nlmsghdr *nlh, struct nft_rule *r)
+{
+ struct nft_rule_expr *expr;
+ struct nlattr *nest;
+
+ if (r->flags & (1 << NFT_RULE_ATTR_TABLE))
+ mnl_attr_put_strz(nlh, NFTA_RULE_TABLE, r->table);
+ if (r->flags & (1 << NFT_RULE_ATTR_CHAIN))
+ mnl_attr_put_strz(nlh, NFTA_RULE_CHAIN, r->chain);
+ if (r->flags & (1 << NFT_RULE_ATTR_HANDLE))
+ mnl_attr_put_u16(nlh, NFTA_RULE_HANDLE, htons(r->handle));
+
+ nest = mnl_attr_nest_start(nlh, NFTA_RULE_EXPRESSIONS);
+ list_for_each_entry(expr, &r->expr_list, head) {
+ nft_rule_expr_build_payload(nlh, expr);
+ }
+ mnl_attr_nest_end(nlh, nest);
+}
+EXPORT_SYMBOL(nft_rule_nlmsg_build_payload);
+
+void nft_rule_add_expr(struct nft_rule *r, struct nft_rule_expr *expr)
+{
+ list_add_tail(&expr->head, &r->expr_list);
+}
+EXPORT_SYMBOL(nft_rule_add_expr);
+
+static int nft_rule_parse_attr_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_RULE_MAX) < 0)
+ return MNL_CB_OK;
+
+ switch(type) {
+ case NFTA_RULE_TABLE:
+ case NFTA_RULE_CHAIN:
+ if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ case NFTA_RULE_HANDLE:
+ if (mnl_attr_validate(attr, MNL_TYPE_U16) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ }
+
+ tb[type] = attr;
+ return MNL_CB_OK;
+}
+
+static int nft_rule_parse_expr_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_EXPR_MAX) < 0)
+ return MNL_CB_OK;
+
+ switch(type) {
+ case NFTA_EXPR_NAME:
+ if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ case NFTA_EXPR_DATA:
+ if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ }
+
+ tb[type] = attr;
+ return MNL_CB_OK;
+}
+
+static int nft_rule_parse_expr2(struct nlattr *attr, struct nft_rule *r)
+{
+ struct nlattr *tb[NFTA_EXPR_MAX+1] = {};
+ struct nft_rule_expr *expr;
+
+ if (mnl_attr_parse_nested(attr, nft_rule_parse_expr_cb, tb) < 0)
+ return -1;
+
+ expr = nft_rule_expr_alloc(mnl_attr_get_str(tb[NFTA_EXPR_NAME]));
+ if (expr == NULL)
+ return -1;
+
+ if (tb[NFTA_EXPR_DATA]) {
+ if (expr->ops->parse(expr, tb[NFTA_EXPR_DATA]) < 0) {
+ free(expr);
+ return -1;
+ }
+ }
+ list_add_tail(&expr->head, &r->expr_list);
+
+ return 0;
+}
+
+static int nft_rule_parse_expr(struct nlattr *nest, struct nft_rule *r)
+{
+ struct nlattr *attr;
+
+ mnl_attr_for_each_nested(attr, nest) {
+ if (mnl_attr_get_type(attr) != NFTA_LIST_ELEM)
+ return -1;
+
+ nft_rule_parse_expr2(attr, r);
+ }
+ return 0;
+}
+
+int nft_rule_nlmsg_parse(const struct nlmsghdr *nlh, struct nft_rule *r)
+{
+ struct nlattr *tb[NFTA_RULE_MAX+1] = {};
+ struct nfgenmsg *nfg = mnl_nlmsg_get_payload(nlh);
+ int ret = 0;
+
+ mnl_attr_parse(nlh, sizeof(*nfg), nft_rule_parse_attr_cb, tb);
+ if (tb[NFTA_RULE_TABLE]) {
+ r->table = strdup(mnl_attr_get_str(tb[NFTA_RULE_TABLE]));
+ r->flags |= (1 << NFT_RULE_ATTR_TABLE);
+ }
+ if (tb[NFTA_RULE_CHAIN]) {
+ r->chain = strdup(mnl_attr_get_str(tb[NFTA_RULE_CHAIN]));
+ r->flags |= (1 << NFT_RULE_ATTR_CHAIN);
+ }
+ if (tb[NFTA_RULE_HANDLE]) {
+ r->handle = ntohs(mnl_attr_get_u16(tb[NFTA_RULE_HANDLE]));
+ r->flags |= (1 << NFT_RULE_ATTR_HANDLE);
+ }
+ if (tb[NFTA_RULE_EXPRESSIONS])
+ ret = nft_rule_parse_expr(tb[NFTA_RULE_EXPRESSIONS], r);
+
+ r->family = nfg->nfgen_family;
+
+ return ret;
+}
+EXPORT_SYMBOL(nft_rule_nlmsg_parse);
+
+int nft_rule_snprintf(char *buf, size_t size, struct nft_rule *r,
+ uint32_t type, uint32_t flags)
+{
+ int ret;
+ struct nft_rule_expr *expr;
+ int len = size, offset = 0;
+
+ ret = snprintf(buf, size, "family=%u table=%s chain=%s handle=%u ",
+ r->family, r->table, r->chain, r->handle);
+ SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+
+ list_for_each_entry(expr, &r->expr_list, head) {
+ ret = snprintf(buf+offset, len, "%s ", expr->ops->name);
+ SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+
+ ret = expr->ops->snprintf(buf+offset, len, expr);
+ SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+ }
+ ret = snprintf(buf+offset-1, len, "\n");
+ SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+
+ return ret;
+}
+EXPORT_SYMBOL(nft_rule_snprintf);
+
+struct nft_rule_expr_iter {
+ struct nft_rule *r;
+ struct nft_rule_expr *cur;
+};
+
+struct nft_rule_expr_iter *nft_rule_expr_iter_create(struct nft_rule *r)
+{
+ struct nft_rule_expr_iter *iter;
+
+ iter = calloc(1, sizeof(struct nft_rule_expr_iter));
+ if (iter == NULL)
+ return NULL;
+
+ iter->r = r;
+ iter->cur = list_entry(r->expr_list.next, struct nft_rule_expr, head);
+
+ return iter;
+}
+EXPORT_SYMBOL(nft_rule_expr_iter_create);
+
+struct nft_rule_expr *nft_rule_expr_iter_next(struct nft_rule_expr_iter *iter)
+{
+ struct nft_rule_expr *expr = iter->cur;
+
+ /* get next expression, if any */
+ iter->cur = list_entry(iter->cur->head.next, struct nft_rule_expr, head);
+ if (&iter->cur->head == iter->r->expr_list.next)
+ return NULL;
+
+ return expr;
+}
+EXPORT_SYMBOL(nft_rule_expr_iter_next);
+
+void nft_rule_expr_iter_destroy(struct nft_rule_expr_iter *iter)
+{
+ free(iter);
+}
+EXPORT_SYMBOL(nft_rule_expr_iter_destroy);
+
+struct nft_rule_list {
+ struct list_head list;
+};
+
+struct nft_rule_list *nft_rule_list_alloc(void)
+{
+ struct nft_rule_list *list;
+
+ list = calloc(1, sizeof(struct nft_rule_list));
+ if (list == NULL)
+ return NULL;
+
+ INIT_LIST_HEAD(&list->list);
+
+ return list;
+}
+EXPORT_SYMBOL(nft_rule_list_alloc);
+
+void nft_rule_list_free(struct nft_rule_list *list)
+{
+ struct nft_rule *r, *tmp;
+
+ list_for_each_entry_safe(r, tmp, &list->list, head) {
+ list_del(&r->head);
+ nft_rule_free(r);
+ }
+ free(list);
+}
+EXPORT_SYMBOL(nft_rule_list_free);
+
+void nft_rule_list_add(struct nft_rule *r, struct nft_rule_list *list)
+{
+ list_add_tail(&r->head, &list->list);
+}
+EXPORT_SYMBOL(nft_rule_list_add);
+
+struct nft_rule_list_iter {
+ struct nft_rule_list *list;
+ struct nft_rule *cur;
+};
+
+struct nft_rule_list_iter *nft_rule_list_iter_create(struct nft_rule_list *l)
+{
+ struct nft_rule_list_iter *iter;
+
+ iter = calloc(1, sizeof(struct nft_rule_list_iter));
+ if (iter == NULL)
+ return NULL;
+
+ iter->list = l;
+ iter->cur = list_entry(l->list.next, struct nft_rule, head);
+
+ return iter;
+}
+EXPORT_SYMBOL(nft_rule_list_iter_create);
+
+struct nft_rule *nft_rule_list_iter_cur(struct nft_rule_list_iter *iter)
+{
+ return iter->cur;
+}
+EXPORT_SYMBOL(nft_rule_list_iter_cur);
+
+struct nft_rule *nft_rule_list_iter_next(struct nft_rule_list_iter *iter)
+{
+ struct nft_rule *r = iter->cur;
+
+ /* get next rule, if any */
+ iter->cur = list_entry(iter->cur->head.next, struct nft_rule, head);
+ if (&iter->cur->head == iter->list->list.next)
+ return NULL;
+
+ return r;
+}
+EXPORT_SYMBOL(nft_rule_list_iter_next);
+
+void nft_rule_list_iter_destroy(struct nft_rule_list_iter *iter)
+{
+ free(iter);
+}
+EXPORT_SYMBOL(nft_rule_list_iter_destroy);