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-rw-r--r--src/expr/cmp.c194
1 files changed, 194 insertions, 0 deletions
diff --git a/src/expr/cmp.c b/src/expr/cmp.c
new file mode 100644
index 0000000..cabaddd
--- /dev/null
+++ b/src/expr/cmp.c
@@ -0,0 +1,194 @@
+/*
+ * (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>
+#include <arpa/inet.h>
+
+#include <libmnl/libmnl.h>
+#include <linux/netfilter/nf_tables.h>
+#include <libnftables/expr.h>
+#include "expr_ops.h"
+#include "data_reg.h"
+
+struct nft_expr_cmp {
+ union nft_data_reg data;
+ uint8_t sreg; /* enum nft_registers */
+ uint8_t op; /* enum nft_cmp_ops */
+};
+
+static int
+nft_rule_expr_cmp_set(struct nft_rule_expr *e, uint16_t type,
+ const void *data, size_t data_len)
+{
+ struct nft_expr_cmp *cmp = (struct nft_expr_cmp *)e->data;
+
+ switch(type) {
+ case NFT_EXPR_CMP_SREG:
+ cmp->sreg = *((uint32_t *)data);
+ break;
+ case NFT_EXPR_CMP_OP:
+ cmp->op = *((uint32_t *)data);
+ break;
+ case NFT_EXPR_CMP_DATA:
+ memcpy(&cmp->data.val, data, data_len);
+ cmp->data.len = data_len;
+ break;
+ default:
+ return -1;
+ }
+ return 0;
+}
+
+static const void *
+nft_rule_expr_cmp_get(struct nft_rule_expr *e, uint16_t type, size_t *data_len)
+{
+ struct nft_expr_cmp *cmp = (struct nft_expr_cmp *)e->data;
+
+ switch(type) {
+ case NFT_EXPR_CMP_SREG:
+ if (e->flags & (1 << NFT_EXPR_CMP_SREG)) {
+ *data_len = sizeof(cmp->sreg);
+ return &cmp->sreg;
+ } else
+ return NULL;
+ break;
+ case NFT_EXPR_CMP_OP:
+ if (e->flags & (1 << NFT_EXPR_CMP_OP)) {
+ *data_len = sizeof(cmp->op);
+ return &cmp->op;
+ } else
+ return NULL;
+ break;
+ case NFT_EXPR_CMP_DATA:
+ if (e->flags & (1 << NFT_EXPR_CMP_DATA)) {
+ *data_len = cmp->data.len;
+ return &cmp->data.val;
+ } else
+ return NULL;
+ break;
+ default:
+ break;
+ }
+ return NULL;
+}
+
+static int nft_rule_expr_cmp_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_CMP_MAX) < 0)
+ return MNL_CB_OK;
+
+ switch(type) {
+ case NFTA_CMP_SREG:
+ case NFTA_CMP_OP:
+ if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ case NFTA_CMP_DATA:
+ if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ }
+
+ tb[type] = attr;
+ return MNL_CB_OK;
+}
+
+static void
+nft_rule_expr_cmp_build(struct nlmsghdr *nlh, struct nft_rule_expr *e)
+{
+ struct nft_expr_cmp *cmp = (struct nft_expr_cmp *)e->data;
+
+ if (e->flags & (1 << NFT_EXPR_CMP_SREG))
+ mnl_attr_put_u32(nlh, NFTA_CMP_SREG, htonl(cmp->sreg));
+ if (e->flags & (1 << NFT_EXPR_CMP_OP))
+ mnl_attr_put_u32(nlh, NFTA_CMP_OP, htonl(cmp->op));
+ if (e->flags & (1 << NFT_EXPR_CMP_DATA)) {
+ struct nlattr *nest;
+
+ nest = mnl_attr_nest_start(nlh, NFTA_CMP_DATA);
+ mnl_attr_put(nlh, NFTA_DATA_VALUE, cmp->data.len, cmp->data.val);
+ mnl_attr_nest_end(nlh, nest);
+ }
+}
+
+static int
+nft_rule_expr_cmp_parse(struct nft_rule_expr *e, struct nlattr *attr)
+{
+ struct nft_expr_cmp *cmp = (struct nft_expr_cmp *)e->data;
+ struct nlattr *tb[NFTA_CMP_MAX+1] = {};
+ int ret = 0;
+
+ if (mnl_attr_parse_nested(attr, nft_rule_expr_cmp_cb, tb) < 0)
+ return -1;
+
+ if (tb[NFTA_CMP_SREG]) {
+ cmp->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_CMP_SREG]));
+ e->flags |= (1 << NFTA_CMP_SREG);
+ }
+ if (tb[NFTA_CMP_OP]) {
+ cmp->op = ntohl(mnl_attr_get_u32(tb[NFTA_CMP_OP]));
+ e->flags |= (1 << NFTA_CMP_OP);
+ }
+ if (tb[NFTA_CMP_DATA]) {
+ ret = nft_parse_data(&cmp->data, tb[NFTA_CMP_DATA], NULL);
+ e->flags |= (1 << NFTA_CMP_DATA);
+ }
+
+ return ret;
+}
+
+static char *expr_cmp_str[] = {
+ [NFT_CMP_EQ] = "eq",
+ [NFT_CMP_NEQ] = "neq",
+ [NFT_CMP_LT] = "lt",
+ [NFT_CMP_LTE] = "lte",
+ [NFT_CMP_GT] = "gt",
+ [NFT_CMP_GTE] = "gte",
+};
+
+static int
+nft_rule_expr_cmp_snprintf(char *buf, size_t size, struct nft_rule_expr *e)
+{
+ struct nft_expr_cmp *cmp = (struct nft_expr_cmp *)e->data;
+ int len = size, offset = 0, ret, i;
+
+ ret = snprintf(buf, len, "sreg=%u op=%s data=",
+ cmp->sreg, expr_cmp_str[cmp->op]);
+ SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+
+ for (i=0; i<cmp->data.len/sizeof(uint32_t); i++) {
+ ret = snprintf(buf+offset, len, "%.8x ", cmp->data.val[i]);
+ SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+ }
+ return offset;
+}
+
+struct expr_ops expr_ops_cmp = {
+ .name = "cmp",
+ .alloc_len = sizeof(struct nft_expr_cmp),
+ .max_attr = NFTA_CMP_MAX,
+ .set = nft_rule_expr_cmp_set,
+ .get = nft_rule_expr_cmp_get,
+ .parse = nft_rule_expr_cmp_parse,
+ .build = nft_rule_expr_cmp_build,
+ .snprintf = nft_rule_expr_cmp_snprintf,
+};