Now it is possible to store multiple variable length user data into rule.
Modify the parser in order to fill the nftnl_udata with the comment, and
the print function for extract these commentary and print it to user.
Signed-off-by: Carlos Falgueras García <carlosfg@xxxxxxxxxx>
---
include/rule.h | 7 +++++++
src/netlink_delinearize.c | 52 +++++++++++++++++++++++++++++++++++++++++++++--
src/netlink_linearize.c | 16 +++++++++++++--
3 files changed, 71 insertions(+), 4 deletions(-)
diff --git a/include/rule.h b/include/rule.h
index c848f0f..b52f0ac 100644
--- a/include/rule.h
+++ b/include/rule.h
@@ -4,6 +4,7 @@
#include <stdint.h>
#include <nftables.h>
#include <list.h>
+#include <libnftnl/udata.h>
/**
* struct handle - handle for tables, chains, rules and sets
@@ -396,4 +397,10 @@ extern int do_command(struct netlink_ctx *ctx, struct cmd *cmd);
extern int cache_update(enum cmd_ops cmd, struct list_head *msgs);
extern void cache_release(void);
+enum udata_type {
+ UDATA_TYPE_COMMENT,
+ __UDATA_TYPE_MAX,
+};
+#define UDATA_TYPE_MAX (__UDATA_TYPE_MAX - 1)
+
#endif /* NFTABLES_RULE_H */
diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index d431588..5fcb5c1 100644
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -25,6 +25,7 @@
#include <utils.h>
#include <erec.h>
#include <sys/socket.h>
+#include <libnftnl/udata.h>
struct netlink_parse_ctx {
struct list_head *msgs;
@@ -1746,6 +1747,54 @@ static void rule_parse_postprocess(struct netlink_parse_ctx *ctx, struct rule *r
}
}
+static int parse_udata_cb(const struct nftnl_udata *attr, void *data)
+{
+ unsigned char *value = nftnl_udata_attr_value(attr);
+ uint8_t type = nftnl_udata_attr_type(attr);
+ uint8_t len = nftnl_udata_attr_len(attr);
+ const struct nftnl_udata **tb = data;
+
+ switch (type) {
+ case UDATA_TYPE_COMMENT:
+ if (value[len - 1] != '\0')
+ return -1;
+ break;
+ default:
+ break;
+ };
+
+ tb[type] = attr;
+ return 1;
+}
+
+static char *udata_get_comment(const void *data, uint32_t data_len)
+{
+ const struct nftnl_udata *tb[UDATA_TYPE_MAX + 1] = {};
+ struct nftnl_udata_buf *udata;
+ uint8_t attr_len;
+ char *comment = NULL;
+
+ udata = nftnl_udata_alloc(data_len);
+ if (!udata)
+ memory_allocation_error();
+ nftnl_udata_copy_data(udata, data, data_len);
+
+ if (nftnl_udata_parse(udata, parse_udata_cb, tb) <= 0)
+ goto exit;
+
+ if (!tb[UDATA_TYPE_COMMENT])
+ goto exit;
+
+ attr_len = nftnl_udata_attr_len(tb[UDATA_TYPE_COMMENT]);
+ comment = xmalloc(attr_len);
+ memcpy(comment, nftnl_udata_attr_value(tb[UDATA_TYPE_COMMENT]),
+ attr_len);
+
+exit:
+ nftnl_udata_free(udata);
+ return comment;
+}
+
struct rule *netlink_delinearize_rule(struct netlink_ctx *ctx,
const struct nftnl_rule *nlr)
{
@@ -1773,8 +1822,7 @@ struct rule *netlink_delinearize_rule(struct netlink_ctx *ctx,
uint32_t len;
data = nftnl_rule_get_data(nlr, NFTNL_RULE_USERDATA, &len);
- pctx->rule->comment = xmalloc(len);
- memcpy((char *)pctx->rule->comment, data, len);
+ pctx->rule->comment = udata_get_comment(data, len);
}
nftnl_expr_foreach((struct nftnl_rule *)nlr, netlink_parse_expr, pctx);
diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index bb51de7..ddf0cd3 100644
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -21,6 +21,7 @@
#include <netinet/in.h>
#include <linux/netfilter.h>
+#include <libnftnl/udata.h>
struct netlink_linearize_ctx {
@@ -1162,6 +1163,7 @@ void netlink_linearize_rule(struct netlink_ctx *ctx, struct nftnl_rule *nlr,
const struct rule *rule)
{
struct netlink_linearize_ctx lctx;
+ struct nftnl_udata_buf *udata;
const struct stmt *stmt;
memset(&lctx, 0, sizeof(lctx));
@@ -1171,9 +1173,19 @@ void netlink_linearize_rule(struct netlink_ctx *ctx, struct nftnl_rule *nlr,
list_for_each_entry(stmt, &rule->stmts, list)
netlink_gen_stmt(&lctx, stmt);
- if (rule->comment)
+ if (rule->comment) {
+ udata = nftnl_udata_alloc(NFT_USERDATA_MAXLEN);
+ if (!udata)
+ memory_allocation_error();
+
+ if (!nftnl_udata_put_strz(udata, UDATA_TYPE_COMMENT,
+ rule->comment))
+ memory_allocation_error();
+
nftnl_rule_set_data(nlr, NFTNL_RULE_USERDATA,
- rule->comment, strlen(rule->comment) + 1);
+ nftnl_udata_data(udata),
+ nftnl_udata_len(udata));
+ }
netlink_dump_rule(nlr);
}
--
2.7.2
--
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