src: attr: Add mnl_attr_get_uint() function

NLA_UINT attributes have a 4-byte payload if possible, and an 8-byte one
if necessary.

There are some NLA_UINT attributes that lack an appropriate getter function.

Add a function mnl_attr_get_uint() to cover that extract these. Since we
need to dispatch on length anyway, make the getter truly universal by
supporting also u8 and u16.

Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: Phil Sutter <phil@nwl.cc>

3 files changed, 27 insertions, 0 deletions

diff --git a/include/libmnl/libmnl.h b/include/libmnl/libmnl.h
index 4bd0b92..9c03280 100644
--- a/include/libmnl/libmnl.h
+++ b/include/libmnl/libmnl.h
@@ -92,6 +92,7 @@ extern uint8_t mnl_attr_get_u8(const struct nlattr *attr);
 extern uint16_t mnl_attr_get_u16(const struct nlattr *attr);
 extern uint32_t mnl_attr_get_u32(const struct nlattr *attr);
 extern uint64_t mnl_attr_get_u64(const struct nlattr *attr);
+extern uint64_t mnl_attr_get_uint(const struct nlattr *attr);
 extern const char *mnl_attr_get_str(const struct nlattr *attr);
 
 /* TLV attribute putters */
diff --git a/src/attr.c b/src/attr.c
index bc39df4..399318e 100644
--- a/src/attr.c
+++ b/src/attr.c
@@ -390,6 +390,28 @@ EXPORT_SYMBOL uint64_t mnl_attr_get_u64(const struct nlattr *attr)
 }
 
 /**
+ * mnl_attr_get_uint - returns 64-bit unsigned integer attribute.
+ * \param attr pointer to netlink attribute
+ *
+ * This function returns the 64-bit value of the attribute payload.
+ */
+EXPORT_SYMBOL uint64_t mnl_attr_get_uint(const struct nlattr *attr)
+{
+	switch (mnl_attr_get_payload_len(attr)) {
+	case sizeof(uint8_t):
+		return mnl_attr_get_u8(attr);
+	case sizeof(uint16_t):
+		return mnl_attr_get_u16(attr);
+	case sizeof(uint32_t):
+		return mnl_attr_get_u32(attr);
+	case sizeof(uint64_t):
+		return mnl_attr_get_u64(attr);
+	}
+
+	return -1ULL;
+}
+
+/**
  * mnl_attr_get_str - get pointer to string attribute
  * \param attr pointer to netlink attribute
  *
diff --git a/src/libmnl.map b/src/libmnl.map
index e5920e5..cd58863 100644
--- a/src/libmnl.map
+++ b/src/libmnl.map
@@ -77,3 +77,7 @@ LIBMNL_1.2 {
   mnl_socket_open2;
   mnl_socket_fdopen;
 } LIBMNL_1.1;
+
+LIBMNL_1.3 {
+  mnl_attr_get_uint;
+} LIBMNL_1.2;