Add rad_get_vendor_attr() for deciphering vendor attributes received

from the RADIUS server.

lib/libradius/libradius.3

@@ -55,6 +55,8 @@
 .Ft int
 .Fn rad_get_attr "struct rad_handle *h" "const void **data" "size_t *len"
 .Ft int
+.Fn rad_get_vendor_attr "u_int32_t *vendor" "const void **data" "size_t *len"
+.Ft int
 .Fn rad_init_send_request "struct rad_handle *h" "int *fd" "struct timeval *tv"
 .Ft int
 .Fn rad_put_addr "struct rad_handle *h" "int type" "struct in_addr addr"
@@ -293,6 +295,22 @@ returns 0.
 If an error such as a malformed attribute is detected, -1 is
 returned.
 .Pp
+If
+.Fn rad_get_attr
+returns
+.Dv RAD_VENDOR_SPECIFIC ,
+.Fn rad_get_vendor_attr
+may be called to determine the vendor.
+The vendor specific RADIUS attribute type is returned.
+The reference parameters
+.Va data
+and
+.Va len
+.Pq as returned from Fn rad_get_attr
+are passed to
+.Fn rad_get_vendor_attr ,
+and are adjusted to point to the vendor specific attribute data.
+.Pp
 The common types of attributes can be decoded using
 .Fn rad_cvt_addr ,
 .Fn rad_cvt_int ,
@@ -300,7 +318,9 @@ and
 .Fn rad_cvt_string .
 These functions accept a pointer to the attribute data, which should
 have been obtained using
-.Fn rad_get_attr .
+.Fn rad_get_attr
+and optionally
+.Fn rad_get_vendor_attr .
 In the case of
 .Fn rad_cvt_string ,
 the length

lib/libradius/radlib.c

@@ -865,6 +865,19 @@ split(char *str, char *fields[], int maxfields, char *msg, size_t msglen)
 	return i;
 }
 
+int
+rad_get_vendor_attr(u_int32_t *vendor, const void **data, size_t *len)
+{
+	struct vendor_attribute *attr;
+
+	attr = (struct vendor_attribute *)*data;
+	*vendor = ntohl(attr->vendor_value);
+	*data = attr->attrib_data;
+	*len = attr->attrib_len - 2;
+
+	return (attr->attrib_type);
+}
+
 int
 rad_put_vendor_addr(struct rad_handle *h, int vendor, int type,
     struct in_addr addr)