conntrack: implement save output format

This commit allows dumping conntrack entries in the format
used by the conntrack parameters, aka "save" output format.
This is useful for saving ct entry data to allow applying
it later on.

To enable the "save" output the "-o save" parameter needs
to be passed to the conntrack tool invocation.

[ pablo@netfilter.org: several updates to the original patch ]

Signed-off-by: Mikhail Sennikovsky <mikhail.sennikovskii@cloud.ionos.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/include/conntrack.h b/include/conntrack.h
index 37ccf6e..1c1720e 100644
--- a/include/conntrack.h
+++ b/include/conntrack.h
@@ -8,6 +8,9 @@
 
 #include <netinet/in.h>
 
+#include <linux/netfilter/nf_conntrack_common.h>
+#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
+
 #define NUMBER_OF_CMD   19
 #define NUMBER_OF_OPT   29
 
@@ -32,6 +35,8 @@ struct ctproto_handler {
 			    unsigned int command,
 			    struct nf_conntrack *ct);
 
+	const struct ct_print_opts *print_opts;
+
 	void (*help)(void);
 
 	struct option 		*opts;
@@ -53,6 +58,31 @@ void exit_error(enum exittype status, const char *msg, ...);
 
 extern void register_proto(struct ctproto_handler *h);
 
+enum ct_attr_type {
+	CT_ATTR_TYPE_NONE = 0,
+	CT_ATTR_TYPE_U8,
+	CT_ATTR_TYPE_BE16,
+	CT_ATTR_TYPE_U16,
+	CT_ATTR_TYPE_BE32,
+	CT_ATTR_TYPE_U32,
+	CT_ATTR_TYPE_U64,
+	CT_ATTR_TYPE_U32_BITMAP,
+	CT_ATTR_TYPE_IPV4,
+	CT_ATTR_TYPE_IPV6,
+};
+
+struct ct_print_opts {
+	const char		*name;
+	enum nf_conntrack_attr	type;
+	enum ct_attr_type	datatype;
+	short			val_mapping_count;
+	const char		**val_mapping;
+};
+
+extern int ct_snprintf_opts(char *buf, unsigned int len,
+			    const struct nf_conntrack *ct,
+			    const struct ct_print_opts *attrs);
+
 extern void register_tcp(void);
 extern void register_udp(void);
 extern void register_udplite(void);