libnetlink: add parse_rtattr_one_nested helper
Sometimes, it is more convenient to get only one specific nested attribute by
type. For example for IFLA_AF_SPEC where type is address family (AF_INET6).
So add this helper for this purpose.
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
diff --git a/include/libnetlink.h b/include/libnetlink.h
index db04969..de7c85f 100644
--- a/include/libnetlink.h
+++ b/include/libnetlink.h
@@ -82,11 +82,15 @@
extern int parse_rtattr_flags(struct rtattr *tb[], int max, struct rtattr *rta,
int len, unsigned short flags);
extern int parse_rtattr_byindex(struct rtattr *tb[], int max, struct rtattr *rta, int len);
+extern struct rtattr *parse_rtattr_one(int type, struct rtattr *rta, int len);
extern int __parse_rtattr_nested_compat(struct rtattr *tb[], int max, struct rtattr *rta, int len);
#define parse_rtattr_nested(tb, max, rta) \
(parse_rtattr((tb), (max), RTA_DATA(rta), RTA_PAYLOAD(rta)))
+#define parse_rtattr_one_nested(type, rta) \
+ (parse_rtattr_one(type, RTA_DATA(rta), RTA_PAYLOAD(rta)))
+
#define parse_rtattr_nested_compat(tb, max, rta, data, len) \
({ data = RTA_PAYLOAD(rta) >= len ? RTA_DATA(rta) : NULL; \
__parse_rtattr_nested_compat(tb, max, rta, len); })
diff --git a/lib/libnetlink.c b/lib/libnetlink.c
index 45ff90a..77e07ef 100644
--- a/lib/libnetlink.c
+++ b/lib/libnetlink.c
@@ -713,6 +713,18 @@
return i;
}
+struct rtattr *parse_rtattr_one(int type, struct rtattr *rta, int len)
+{
+ while (RTA_OK(rta, len)) {
+ if (rta->rta_type == type)
+ return rta;
+ rta = RTA_NEXT(rta, len);
+ }
+ if (len)
+ fprintf(stderr, "!!!Deficit %d, rta_len=%d\n", len, rta->rta_len);
+ return NULL;
+}
+
int __parse_rtattr_nested_compat(struct rtattr *tb[], int max, struct rtattr *rta,
int len)
{