libnetlink: add nl_print_policy() helper

This prints out the data from the given nested attribute
to the given FILE pointer, interpreting the firmware that
the kernel has for showing netlink policies.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David Ahern <dsahern@gmail.com>

diff --git a/include/libnetlink.h b/include/libnetlink.h
index 0d4a9f29afbde7020210f4fed2cea479e83b6c71..b9073a6a13adec78afdcf2580f6b37c744d95a2a 100644 (file)
--- a/include/libnetlink.h
+++ b/include/libnetlink.h
@@ -289,4 +289,6 @@ int rtnl_from_file(FILE *, rtnl_listen_filter_t handler,
             RTA_OK(attr, RTA_PAYLOAD(nest) - ((char *)(attr) - (char *)RTA_DATA((nest)))); \
             (attr) = RTA_TAIL((attr)))
 
+void nl_print_policy(const struct rtattr *attr, FILE *fp);
+
 #endif /* __LIBNETLINK_H__ */

diff --git a/lib/libnetlink.c b/lib/libnetlink.c
index e02d6294b02e6ea29b2a079fa6702b16b0412e02..a7b60d873afba759702f3ee186e32ba9248e9302 100644 (file)
--- a/lib/libnetlink.c
+++ b/lib/libnetlink.c
@@ -28,6 +28,7 @@
 #include <linux/nexthop.h>
 
 #include "libnetlink.h"
+#include "utils.h"
 
 #define __aligned(x)           __attribute__((aligned(x)))
 
@@ -1440,3 +1441,75 @@ int __parse_rtattr_nested_compat(struct rtattr *tb[], int max,
        memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
        return 0;
 }
+
+static const char *get_nla_type_str(unsigned int attr)
+{
+       switch (attr) {
+#define C(x) case NL_ATTR_TYPE_ ## x: return #x
+       C(U8);
+       C(U16);
+       C(U32);
+       C(U64);
+       C(STRING);
+       C(FLAG);
+       C(NESTED);
+       C(NESTED_ARRAY);
+       C(NUL_STRING);
+       C(BINARY);
+       C(S8);
+       C(S16);
+       C(S32);
+       C(S64);
+       C(BITFIELD32);
+       default:
+               return "unknown";
+       }
+}
+
+void nl_print_policy(const struct rtattr *attr, FILE *fp)
+{
+       const struct rtattr *pos;
+
+       rtattr_for_each_nested(pos, attr) {
+               const struct rtattr *attr;
+
+               fprintf(fp, " policy[%u]:", pos->rta_type & ~NLA_F_NESTED);
+
+               rtattr_for_each_nested(attr, pos) {
+                       struct rtattr *tp[NL_POLICY_TYPE_ATTR_MAX + 1];
+
+                       parse_rtattr_nested(tp, ARRAY_SIZE(tp) - 1, attr);
+
+                       if (tp[NL_POLICY_TYPE_ATTR_TYPE])
+                               fprintf(fp, "attr[%u]: type=%s",
+                                       attr->rta_type & ~NLA_F_NESTED,
+                                       get_nla_type_str(rta_getattr_u32(tp[NL_POLICY_TYPE_ATTR_TYPE])));
+
+                       if (tp[NL_POLICY_TYPE_ATTR_POLICY_IDX])
+                               fprintf(fp, " policy:%u",
+                                       rta_getattr_u32(tp[NL_POLICY_TYPE_ATTR_POLICY_IDX]));
+
+                       if (tp[NL_POLICY_TYPE_ATTR_POLICY_MAXTYPE])
+                               fprintf(fp, " maxattr:%u",
+                                       rta_getattr_u32(tp[NL_POLICY_TYPE_ATTR_POLICY_MAXTYPE]));
+
+                       if (tp[NL_POLICY_TYPE_ATTR_MIN_VALUE_S] && tp[NL_POLICY_TYPE_ATTR_MAX_VALUE_S])
+                               fprintf(fp, " range:[%lld,%lld]",
+                                       (signed long long)rta_getattr_u64(tp[NL_POLICY_TYPE_ATTR_MIN_VALUE_S]),
+                                       (signed long long)rta_getattr_u64(tp[NL_POLICY_TYPE_ATTR_MAX_VALUE_S]));
+
+                       if (tp[NL_POLICY_TYPE_ATTR_MIN_VALUE_U] && tp[NL_POLICY_TYPE_ATTR_MAX_VALUE_U])
+                               fprintf(fp, " range:[%llu,%llu]",
+                                       (unsigned long long)rta_getattr_u64(tp[NL_POLICY_TYPE_ATTR_MIN_VALUE_U]),
+                                       (unsigned long long)rta_getattr_u64(tp[NL_POLICY_TYPE_ATTR_MAX_VALUE_U]));
+
+                       if (tp[NL_POLICY_TYPE_ATTR_MIN_LENGTH])
+                               fprintf(fp, " min len:%u",
+                                       rta_getattr_u32(tp[NL_POLICY_TYPE_ATTR_MIN_LENGTH]));
+
+                       if (tp[NL_POLICY_TYPE_ATTR_MAX_LENGTH])
+                               fprintf(fp, " max len:%u",
+                                       rta_getattr_u32(tp[NL_POLICY_TYPE_ATTR_MAX_LENGTH]));
+               }
+       }
+}