From: Alan T. DeKok <aland@freeradius.org>
Date: Thu, 31 Oct 2019 19:06:48 +0000 (-0400)
Subject: allow 'length=uint16' as a flag
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fa8eef571e43c7ffd6de7d51865b67f67f6fc523;p=thirdparty%2Ffreeradius-server.git

allow 'length=uint16' as a flag

This is mainly for DHCPv6, but it allows us to auto-encode lengths
inside of structs too, which wasn't previously possible.
---

diff --git a/src/lib/util/dict.h b/src/lib/util/dict.h
index 0c2052fc821..0715e479e82 100644
--- a/src/lib/util/dict.h
+++ b/src/lib/util/dict.h
@@ -99,9 +99,11 @@ enum {
 enum {
 	FLAG_EXTRA_NONE = 0,				//!< no extra meaning, should be invalid
 	FLAG_KEY_FIELD,					//!< this is a key field for a subsequent struct
+	FLAG_LENGTH_UINT16,			       	//!< string / octets type is prefixed by uint16 of length
 };
 
 #define da_is_key_field(_da) ((_da)->flags.extra && ((_da)->flags.subtype == FLAG_KEY_FIELD))
+#define da_is_length_field(_da) ((_da)->flags.extra && ((_da)->flags.subtype == FLAG_LENGTH_UINT16))
 
 extern const size_t dict_attr_sizes[FR_TYPE_MAX + 1][2];
 extern fr_dict_t *fr_dict_internal;
diff --git a/src/lib/util/dict_print.c b/src/lib/util/dict_print.c
index 286fc9441e3..64b5fddd4c4 100644
--- a/src/lib/util/dict_print.c
+++ b/src/lib/util/dict_print.c
@@ -52,7 +52,7 @@ do { \
 	FLAG_SET(concat);
 	FLAG_SET(virtual);
 
-	if (dict && flags->subtype) {
+	if (dict && !flags->extra && flags->subtype) {
 		p += snprintf(p, end - p, "%s", fr_table_str_by_value(dict->subtype_table, flags->subtype, "?"));
 		if (p >= end) return -1;
 	}
@@ -63,13 +63,15 @@ do { \
 	}
 
 	if (flags->extra) {
-		switch (type) {
-		case FR_TYPE_UINT8:
-		case FR_TYPE_UINT16:
-		case FR_TYPE_UINT32:
+		switch (flags->subtype) {
+		case FLAG_KEY_FIELD:
 			p += snprintf(p, end - p, "key,");
 			break;
 
+		case FLAG_LENGTH_UINT16:
+			p += snprintf(p, end - p, "length=uint16,");
+			break;
+
 		default:
 			break;
 		}
diff --git a/src/lib/util/dict_tokenize.c b/src/lib/util/dict_tokenize.c
index e9c02a270b3..f3cf192f924 100644
--- a/src/lib/util/dict_tokenize.c
+++ b/src/lib/util/dict_tokenize.c
@@ -343,6 +343,19 @@ static int dict_process_flag_field(dict_tokenize_ctx_t *ctx, char *name, fr_type
 			flags->extra = 1;
 			flags->subtype = FLAG_KEY_FIELD;
 
+		} else if (strcmp(key, "length") == 0) {
+			if (!value || (strcmp(value, "uint16") != 0)) {
+				fr_strerror_printf("The 'length' flag can only be used with value 'uint16'");
+			}
+
+			if ((type != FR_TYPE_STRING) && (type != FR_TYPE_OCTETS) && (type != FR_TYPE_UINT32)) {
+				fr_strerror_printf("The 'length' flag can only be used for attributes of type 'string' or 'octets'");
+				return -1;
+			}
+
+			flags->extra = 1;
+			flags->subtype = FLAG_LENGTH_UINT16;
+
 		} else if ((type == FR_TYPE_DATE) || (type == FR_TYPE_TIME_DELTA)) {
 			flags->length = 4;
 			flags->type_size = FR_TIME_RES_SEC;
diff --git a/src/lib/util/dict_validate.c b/src/lib/util/dict_validate.c
index 00c6a1c2f58..e15e08441fe 100644
--- a/src/lib/util/dict_validate.c
+++ b/src/lib/util/dict_validate.c
@@ -160,7 +160,12 @@ bool dict_attr_flags_valid(fr_dict_t *dict, fr_dict_attr_t const *parent,
 			break;
 		}
 
+		/*
+		 *	DHCPv6 has arrays of string / octets, prefixed
+		 *	with a uint16 field of "length".  Also, arrays of dns_labels.
+		 */
 		if (dict->root->attr == FR_PROTOCOL_DHCPV6) {
+			ALLOW_FLAG(extra);
 			ALLOW_FLAG(subtype);
 		}
 
@@ -221,8 +226,8 @@ bool dict_attr_flags_valid(fr_dict_t *dict, fr_dict_attr_t const *parent,
 	 *	the data type.
 	 */
 	if (flags->extra) {
-		if (flags->subtype != FLAG_KEY_FIELD) {
-			fr_strerror_printf("The 'key' flag cannot be used with any other flags.");
+		if ((flags->subtype != FLAG_KEY_FIELD) && (flags->subtype != FLAG_LENGTH_UINT16)) {
+			fr_strerror_printf("The 'key' and 'length' flags cannot be used with any other flags.");
 			return false;
 		}
 
@@ -230,17 +235,39 @@ bool dict_attr_flags_valid(fr_dict_t *dict, fr_dict_attr_t const *parent,
 		case FR_TYPE_UINT8:
 		case FR_TYPE_UINT16:
 		case FR_TYPE_UINT32:
-			ALLOW_FLAG(extra);
-			ALLOW_FLAG(subtype);
+			if (flags->subtype != FLAG_KEY_FIELD) {
+				fr_strerror_printf("Invalid type for extra flag.");
+				return false;
+			}
+
 			if (parent->type != FR_TYPE_STRUCT) {
 				fr_strerror_printf("The 'key' flag can only be used inside of a 'struct'.");
 				return false;
 			}
 
+			ALLOW_FLAG(extra);
+			ALLOW_FLAG(subtype);
+			break;
+
+		case FR_TYPE_OCTETS:
+			if (flags->length != 0) {
+				fr_strerror_printf("Cannot use [..] and length=uint16");
+				return false;
+			}
+			/* FALL-THROUGH */
+
+		case FR_TYPE_STRING:
+			if (flags->subtype != FLAG_LENGTH_UINT16) {
+				fr_strerror_printf("Invalid type for extra flag.");
+				return false;
+			}
+
+			ALLOW_FLAG(extra);
+			ALLOW_FLAG(array);
+			ALLOW_FLAG(subtype);
 			break;
 
 		default:
-			fr_strerror_printf("The 'key' flag can only be used with unsigned integer data types");
 			return -1;
 		}