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authorPablo Neira Ayuso <pablo@netfilter.org>2013-02-05 14:01:39 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2013-02-07 22:47:17 +0100
commit1cef3296c64244736a000ab0d146d05ca1ac4b8b (patch)
treee66c2e5756a29a1c8c1a64830b097667f2da1428 /src/expr/lookup.c
parentd2a0036dd3e16d40f4039a11677241827ea057c5 (diff)
expr: add lookup expression for set-based lookups
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'src/expr/lookup.c')
-rw-r--r--src/expr/lookup.c175
1 files changed, 175 insertions, 0 deletions
diff --git a/src/expr/lookup.c b/src/expr/lookup.c
new file mode 100644
index 0000000..8e533c4
--- /dev/null
+++ b/src/expr/lookup.c
@@ -0,0 +1,175 @@
+/*
+ * (C) 2012-2013 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 <libmnl/libmnl.h>
+#include <linux/netfilter/nf_tables.h>
+#include <libnftables/expr.h>
+#include "data_reg.h"
+#include "expr_ops.h"
+
+#ifndef IFNAMSIZ
+#define IFNAMSIZ 16
+#endif
+
+struct nft_expr_lookup {
+ enum nft_registers sreg;
+ enum nft_registers dreg;
+ char set_name[IFNAMSIZ];
+};
+
+static int
+nft_rule_expr_lookup_set(struct nft_rule_expr *e, uint16_t type,
+ const void *data, size_t data_len)
+{
+ struct nft_expr_lookup *lookup = (struct nft_expr_lookup *)e->data;
+
+ switch(type) {
+ case NFT_EXPR_LOOKUP_SREG:
+ lookup->sreg = *((uint32_t *)data);
+ break;
+ case NFT_EXPR_LOOKUP_DREG:
+ lookup->dreg = *((uint32_t *)data);
+ break;
+ case NFT_EXPR_LOOKUP_SET:
+ memcpy(lookup->set_name, data, IFNAMSIZ);
+ lookup->set_name[IFNAMSIZ-1] = '\0';
+ break;
+ default:
+ return -1;
+ }
+ return 0;
+}
+
+static const void *
+nft_rule_expr_lookup_get(struct nft_rule_expr *e, uint16_t type, size_t *data_len)
+{
+ struct nft_expr_lookup *lookup = (struct nft_expr_lookup *)e->data;
+
+ switch(type) {
+ case NFT_EXPR_LOOKUP_SREG:
+ if (e->flags & (1 << NFT_EXPR_LOOKUP_SREG)) {
+ *data_len = sizeof(lookup->sreg);
+ return &lookup->sreg;
+ }
+ break;
+ case NFT_EXPR_LOOKUP_DREG:
+ if (e->flags & (1 << NFT_EXPR_LOOKUP_DREG)) {
+ *data_len = sizeof(lookup->dreg);
+ return &lookup->dreg;
+ }
+ break;
+ case NFT_EXPR_LOOKUP_SET:
+ if (e->flags & (1 << NFT_EXPR_LOOKUP_SET))
+ return lookup->set_name;
+ break;
+ default:
+ break;
+ }
+ return NULL;
+}
+
+static int nft_rule_expr_lookup_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_LOOKUP_MAX) < 0)
+ return MNL_CB_OK;
+
+ switch(type) {
+ case NFTA_LOOKUP_SREG:
+ case NFTA_LOOKUP_DREG:
+ if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ case NFTA_LOOKUP_SET:
+ if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ }
+
+ tb[type] = attr;
+ return MNL_CB_OK;
+}
+
+static void
+nft_rule_expr_lookup_build(struct nlmsghdr *nlh, struct nft_rule_expr *e)
+{
+ struct nft_expr_lookup *lookup = (struct nft_expr_lookup *)e->data;
+
+ if (e->flags & (1 << NFT_EXPR_LOOKUP_SREG))
+ mnl_attr_put_u32(nlh, NFTA_LOOKUP_SREG, htonl(lookup->sreg));
+ if (e->flags & (1 << NFT_EXPR_LOOKUP_DREG))
+ mnl_attr_put_u32(nlh, NFTA_LOOKUP_DREG, htonl(lookup->dreg));
+ if (e->flags & (1 << NFT_EXPR_LOOKUP_SET))
+ mnl_attr_put_strz(nlh, NFTA_LOOKUP_SET, lookup->set_name);
+}
+
+static int
+nft_rule_expr_lookup_parse(struct nft_rule_expr *e, struct nlattr *attr)
+{
+ struct nft_expr_lookup *lookup = (struct nft_expr_lookup *)e->data;
+ struct nlattr *tb[NFTA_LOOKUP_MAX+1] = {};
+ int ret = 0;
+
+ if (mnl_attr_parse_nested(attr, nft_rule_expr_lookup_cb, tb) < 0)
+ return -1;
+
+ if (tb[NFTA_LOOKUP_SREG]) {
+ lookup->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_SREG]));
+ e->flags |= (1 << NFT_EXPR_LOOKUP_SREG);
+ }
+ if (tb[NFTA_LOOKUP_DREG]) {
+ lookup->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_DREG]));
+ e->flags |= (1 << NFT_EXPR_LOOKUP_DREG);
+ }
+ if (tb[NFTA_LOOKUP_SET]) {
+ strcpy(lookup->set_name, mnl_attr_get_str(tb[NFTA_LOOKUP_SET]));
+ e->flags |= (1 << NFT_EXPR_LOOKUP_SET);
+ }
+
+ return ret;
+}
+
+static int
+nft_rule_expr_lookup_snprintf(char *buf, size_t size, uint32_t type,
+ uint32_t flags, struct nft_rule_expr *e)
+{
+ struct nft_expr_lookup *lookup = (struct nft_expr_lookup *)e->data;
+ int len = size, offset = 0, ret;
+
+ ret = snprintf(buf, len, "set=%s sreg=%u dreg=%u\n",
+ lookup->set_name, lookup->sreg, lookup->dreg);
+ SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+
+ return offset;
+}
+
+struct expr_ops expr_ops_lookup = {
+ .name = "lookup",
+ .alloc_len = sizeof(struct nft_expr_lookup),
+ .max_attr = NFTA_LOOKUP_MAX,
+ .set = nft_rule_expr_lookup_set,
+ .get = nft_rule_expr_lookup_get,
+ .parse = nft_rule_expr_lookup_parse,
+ .build = nft_rule_expr_lookup_build,
+ .snprintf = nft_rule_expr_lookup_snprintf,
+};