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authorPablo Neira Ayuso <pablo@netfilter.org>2016-09-20 17:53:21 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2016-10-13 10:31:15 +0200
commit200da4866ada06b2ee0f708c93dbdf9dcd0fcfe4 (patch)
tree62e494df34d41ad1acf94e1ab54b11365651cc4a /src/expr
parentc11103944cee05fbd1bba7ed60b017b6bd4ad57b (diff)
src: add range expression
Add range expression available that is scheduled for linux kernel 4.9. This range expression allows us to check if a given value placed in a register is within/outside a specified interval. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'src/expr')
-rw-r--r--src/expr/range.c288
1 files changed, 288 insertions, 0 deletions
diff --git a/src/expr/range.c b/src/expr/range.c
new file mode 100644
index 0000000..1489d58
--- /dev/null
+++ b/src/expr/range.c
@@ -0,0 +1,288 @@
+/*
+ * (C) 2016 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.
+ */
+
+#include "internal.h"
+
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <arpa/inet.h>
+#include <errno.h>
+
+#include <libmnl/libmnl.h>
+#include <linux/netfilter/nf_tables.h>
+#include <libnftnl/expr.h>
+#include <libnftnl/rule.h>
+
+struct nftnl_expr_range {
+ union nftnl_data_reg data_from;
+ union nftnl_data_reg data_to;
+ enum nft_registers sreg;
+ enum nft_range_ops op;
+};
+
+static int nftnl_expr_range_set(struct nftnl_expr *e, uint16_t type,
+ const void *data, uint32_t data_len)
+{
+ struct nftnl_expr_range *range = nftnl_expr_data(e);
+
+ switch(type) {
+ case NFTNL_EXPR_RANGE_SREG:
+ range->sreg = *((uint32_t *)data);
+ break;
+ case NFTNL_EXPR_RANGE_OP:
+ range->op = *((uint32_t *)data);
+ break;
+ case NFTNL_EXPR_RANGE_FROM_DATA:
+ memcpy(&range->data_from.val, data, data_len);
+ range->data_from.len = data_len;
+ break;
+ case NFTNL_EXPR_RANGE_TO_DATA:
+ memcpy(&range->data_to.val, data, data_len);
+ range->data_to.len = data_len;
+ break;
+ default:
+ return -1;
+ }
+ return 0;
+}
+
+static const void *nftnl_expr_range_get(const struct nftnl_expr *e,
+ uint16_t type, uint32_t *data_len)
+{
+ struct nftnl_expr_range *range = nftnl_expr_data(e);
+
+ switch(type) {
+ case NFTNL_EXPR_RANGE_SREG:
+ *data_len = sizeof(range->sreg);
+ return &range->sreg;
+ case NFTNL_EXPR_RANGE_OP:
+ *data_len = sizeof(range->op);
+ return &range->op;
+ case NFTNL_EXPR_RANGE_FROM_DATA:
+ *data_len = range->data_from.len;
+ return &range->data_from.val;
+ case NFTNL_EXPR_RANGE_TO_DATA:
+ *data_len = range->data_to.len;
+ return &range->data_to.val;
+ }
+ return NULL;
+}
+
+static int nftnl_expr_range_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_RANGE_MAX) < 0)
+ return MNL_CB_OK;
+
+ switch(type) {
+ case NFTA_RANGE_SREG:
+ case NFTA_RANGE_OP:
+ if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
+ abi_breakage();
+ break;
+ case NFTA_RANGE_FROM_DATA:
+ case NFTA_RANGE_TO_DATA:
+ if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0)
+ abi_breakage();
+ break;
+ }
+
+ tb[type] = attr;
+ return MNL_CB_OK;
+}
+
+static void
+nftnl_expr_range_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
+{
+ struct nftnl_expr_range *range = nftnl_expr_data(e);
+
+ if (e->flags & (1 << NFTNL_EXPR_RANGE_SREG))
+ mnl_attr_put_u32(nlh, NFTA_RANGE_SREG, htonl(range->sreg));
+ if (e->flags & (1 << NFTNL_EXPR_RANGE_OP))
+ mnl_attr_put_u32(nlh, NFTA_RANGE_OP, htonl(range->op));
+ if (e->flags & (1 << NFTNL_EXPR_RANGE_FROM_DATA)) {
+ struct nlattr *nest;
+
+ nest = mnl_attr_nest_start(nlh, NFTA_RANGE_FROM_DATA);
+ mnl_attr_put(nlh, NFTA_DATA_VALUE, range->data_from.len,
+ range->data_from.val);
+ mnl_attr_nest_end(nlh, nest);
+ }
+ if (e->flags & (1 << NFTNL_EXPR_RANGE_TO_DATA)) {
+ struct nlattr *nest;
+
+ nest = mnl_attr_nest_start(nlh, NFTA_RANGE_TO_DATA);
+ mnl_attr_put(nlh, NFTA_DATA_VALUE, range->data_to.len,
+ range->data_to.val);
+ mnl_attr_nest_end(nlh, nest);
+ }
+}
+
+static int
+nftnl_expr_range_parse(struct nftnl_expr *e, struct nlattr *attr)
+{
+ struct nftnl_expr_range *range = nftnl_expr_data(e);
+ struct nlattr *tb[NFTA_RANGE_MAX+1] = {};
+ int ret = 0;
+
+ if (mnl_attr_parse_nested(attr, nftnl_expr_range_cb, tb) < 0)
+ return -1;
+
+ if (tb[NFTA_RANGE_SREG]) {
+ range->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_RANGE_SREG]));
+ e->flags |= (1 << NFTA_RANGE_SREG);
+ }
+ if (tb[NFTA_RANGE_OP]) {
+ range->op = ntohl(mnl_attr_get_u32(tb[NFTA_RANGE_OP]));
+ e->flags |= (1 << NFTA_RANGE_OP);
+ }
+ if (tb[NFTA_RANGE_FROM_DATA]) {
+ ret = nftnl_parse_data(&range->data_from,
+ tb[NFTA_RANGE_FROM_DATA], NULL);
+ e->flags |= (1 << NFTA_RANGE_FROM_DATA);
+ }
+ if (tb[NFTA_RANGE_TO_DATA]) {
+ ret = nftnl_parse_data(&range->data_to,
+ tb[NFTA_RANGE_TO_DATA], NULL);
+ e->flags |= (1 << NFTA_RANGE_TO_DATA);
+ }
+
+ return ret;
+}
+
+static char *expr_range_str[] = {
+ [NFT_RANGE_EQ] = "eq",
+ [NFT_RANGE_NEQ] = "neq",
+};
+
+static const char *range2str(uint32_t op)
+{
+ if (op > NFT_RANGE_NEQ)
+ return "unknown";
+
+ return expr_range_str[op];
+}
+
+static inline int nftnl_str2range(const char *op)
+{
+ if (strcmp(op, "eq") == 0)
+ return NFT_RANGE_EQ;
+ else if (strcmp(op, "neq") == 0)
+ return NFT_RANGE_NEQ;
+ else {
+ errno = EINVAL;
+ return -1;
+ }
+}
+
+static int nftnl_expr_range_json_parse(struct nftnl_expr *e, json_t *root,
+ struct nftnl_parse_err *err)
+{
+#ifdef JSON_PARSING
+ struct nftnl_expr_range *range = nftnl_expr_data(e);
+ const char *op;
+ uint32_t uval32;
+ int base;
+
+ if (nftnl_jansson_parse_val(root, "sreg", NFTNL_TYPE_U32, &uval32,
+ err) == 0)
+ nftnl_expr_set_u32(e, NFTNL_EXPR_RANGE_SREG, uval32);
+
+ op = nftnl_jansson_parse_str(root, "op", err);
+ if (op != NULL) {
+ base = nftnl_str2range(op);
+ if (base < 0)
+ return -1;
+
+ nftnl_expr_set_u32(e, NFTNL_EXPR_RANGE_OP, base);
+ }
+
+ if (nftnl_jansson_data_reg_parse(root, "data_from",
+ &range->data_from, err) == DATA_VALUE)
+ e->flags |= (1 << NFTNL_EXPR_RANGE_FROM_DATA);
+
+ if (nftnl_jansson_data_reg_parse(root, "data_to",
+ &range->data_to, err) == DATA_VALUE)
+ e->flags |= (1 << NFTNL_EXPR_RANGE_TO_DATA);
+
+ return 0;
+#else
+ errno = EOPNOTSUPP;
+ return -1;
+#endif
+}
+
+static int nftnl_expr_range_export(char *buf, size_t size,
+ const struct nftnl_expr *e, int type)
+{
+ struct nftnl_expr_range *range = nftnl_expr_data(e);
+ NFTNL_BUF_INIT(b, buf, size);
+
+ if (e->flags & (1 << NFTNL_EXPR_RANGE_SREG))
+ nftnl_buf_u32(&b, type, range->sreg, SREG);
+ if (e->flags & (1 << NFTNL_EXPR_RANGE_OP))
+ nftnl_buf_str(&b, type, range2str(range->op), OP);
+ if (e->flags & (1 << NFTNL_EXPR_RANGE_FROM_DATA))
+ nftnl_buf_reg(&b, type, &range->data_from, DATA_VALUE, DATA);
+ if (e->flags & (1 << NFTNL_EXPR_RANGE_TO_DATA))
+ nftnl_buf_reg(&b, type, &range->data_to, DATA_VALUE, DATA);
+
+ return nftnl_buf_done(&b);
+}
+
+static int nftnl_expr_range_snprintf_default(char *buf, size_t size,
+ const struct nftnl_expr *e)
+{
+ struct nftnl_expr_range *range = nftnl_expr_data(e);
+ int len = size, offset = 0, ret;
+
+ ret = snprintf(buf, len, "%s reg %u ",
+ expr_range_str[range->op], range->sreg);
+ SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+
+ ret = nftnl_data_reg_snprintf(buf + offset, len, &range->data_from,
+ NFTNL_OUTPUT_DEFAULT, 0, DATA_VALUE);
+ SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+
+ ret = nftnl_data_reg_snprintf(buf + offset, len, &range->data_to,
+ NFTNL_OUTPUT_DEFAULT, 0, DATA_VALUE);
+ SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+
+ return offset;
+}
+
+static int nftnl_expr_range_snprintf(char *buf, size_t size, uint32_t type,
+ uint32_t flags, const struct nftnl_expr *e)
+{
+ switch (type) {
+ case NFTNL_OUTPUT_DEFAULT:
+ return nftnl_expr_range_snprintf_default(buf, size, e);
+ case NFTNL_OUTPUT_XML:
+ case NFTNL_OUTPUT_JSON:
+ return nftnl_expr_range_export(buf, size, e, type);
+ default:
+ break;
+ }
+ return -1;
+}
+
+struct expr_ops expr_ops_range = {
+ .name = "range",
+ .alloc_len = sizeof(struct nftnl_expr_range),
+ .max_attr = NFTA_RANGE_MAX,
+ .set = nftnl_expr_range_set,
+ .get = nftnl_expr_range_get,
+ .parse = nftnl_expr_range_parse,
+ .build = nftnl_expr_range_build,
+ .snprintf = nftnl_expr_range_snprintf,
+ .json_parse = nftnl_expr_range_json_parse,
+};