conntrack: add nfct_set_attr_l and ATTR_HELPER_INFO

This adds the ATTR_HELPER_INFO that can be used to send binary data
that will be attached to the conntrack. This is useful for the
user-space connection tracking support.

This patch also adds a new interface:

 nfct_set_attr_l(attr, type, value, length);

that is used to set the variable length helper information.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

4 files changed, 11 insertions, 1 deletions

diff --git a/include/internal/object.h b/include/internal/object.h
index 55fa4f5..443e800 100644
--- a/include/internal/object.h
+++ b/include/internal/object.h
@@ -186,6 +186,9 @@ struct nf_conntrack {
 		u_int64_t	start;
 		u_int64_t	stop;
 	} timestamp;
+
+	void *helper_info;
+	size_t helper_info_len;
 };
 
 /*
diff --git a/include/internal/types.h b/include/internal/types.h
index 3459200..49bac2e 100644
--- a/include/internal/types.h
+++ b/include/internal/types.h
@@ -7,7 +7,7 @@
 /*
  * conntrack types
  */
-typedef void (*set_attr)(struct nf_conntrack *ct, const void *value);
+typedef void (*set_attr)(struct nf_conntrack *ct, const void *value, size_t len);
 typedef const void *(*get_attr)(const struct nf_conntrack *ct);
 typedef void (*copy_attr)(struct nf_conntrack *d, const struct nf_conntrack *o);
 typedef void (*filter_attr)(struct nfct_filter *filter, const void *value);
diff --git a/include/libnetfilter_conntrack/libnetfilter_conntrack.h b/include/libnetfilter_conntrack/libnetfilter_conntrack.h
index fbd67ef..12f61d1 100644
--- a/include/libnetfilter_conntrack/libnetfilter_conntrack.h
+++ b/include/libnetfilter_conntrack/libnetfilter_conntrack.h
@@ -132,6 +132,7 @@ enum nf_conntrack_attr {
 	ATTR_SECCTX,				/* string */
 	ATTR_TIMESTAMP_START,			/* u64 bits, linux >= 2.6.38 */
 	ATTR_TIMESTAMP_STOP = 64,		/* u64 bits, linux >= 2.6.38 */
+	ATTR_HELPER_INFO,			/* variable length */
 	ATTR_MAX
 };
 
@@ -293,6 +294,11 @@ extern void nfct_set_attr_u64(struct nf_conntrack *ct,
 			      const enum nf_conntrack_attr type,
 			      u_int64_t value);
 
+extern void nfct_set_attr_l(struct nf_conntrack *ct,
+			    const enum nf_conntrack_attr type,
+			    const void *value,
+			    size_t len);
+
 /* getter */
 extern const void *nfct_get_attr(const struct nf_conntrack *ct,
 				 const enum nf_conntrack_attr type);
diff --git a/include/libnetfilter_conntrack/linux_nfnetlink_conntrack.h b/include/libnetfilter_conntrack/linux_nfnetlink_conntrack.h
index 1cf938b..e927699 100644
--- a/include/libnetfilter_conntrack/linux_nfnetlink_conntrack.h
+++ b/include/libnetfilter_conntrack/linux_nfnetlink_conntrack.h
@@ -195,6 +195,7 @@ enum ctattr_expect_nat {
 enum ctattr_help {
 	CTA_HELP_UNSPEC,
 	CTA_HELP_NAME,
+	CTA_HELP_INFO,
 	__CTA_HELP_MAX
 };
 #define CTA_HELP_MAX (__CTA_HELP_MAX - 1)