From: Alan T. DeKok <aland@freeradius.org>
Date: Wed, 16 Mar 2022 13:37:01 +0000 (-0400)
Subject: add fr_dhcpv4_attr_sizes[] and fr_dhcpv4_option_len()
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=023237db13e2278515e41d728fbbfd3c2aa53d7b;p=thirdparty%2Ffreeradius-server.git

add fr_dhcpv4_attr_sizes[] and fr_dhcpv4_option_len()
---

diff --git a/src/protocols/dhcpv4/base.c b/src/protocols/dhcpv4/base.c
index 00a0a9b2096..724b4a13b1e 100644
--- a/src/protocols/dhcpv4/base.c
+++ b/src/protocols/dhcpv4/base.c
@@ -97,6 +97,31 @@ fr_dict_attr_autoload_t dhcpv4_dict_attr[] = {
 	{ NULL }
 };
 
+size_t const fr_dhcpv4_attr_sizes[FR_TYPE_MAX + 1][2] = {
+	[FR_TYPE_NULL]		= {~0, 0},
+
+	[FR_TYPE_STRING]		= {0, ~0},
+	[FR_TYPE_OCTETS]		= {0, ~0},
+
+	[FR_TYPE_IPV4_ADDR]		= {4, 4},
+	[FR_TYPE_IPV4_PREFIX]		= {1, 5},	//!< Zero length prefix still requires one byte for prefix len.
+	[FR_TYPE_IPV6_ADDR]		= {16, 16},
+	[FR_TYPE_IPV6_PREFIX]		= {1, 17},	//!< Zero length prefix still requires one byte for prefix len.
+	[FR_TYPE_IFID]			= {8, 8},
+	[FR_TYPE_ETHERNET]		= {6, 6},
+
+	[FR_TYPE_BOOL]			= {1, 1},
+	[FR_TYPE_UINT8]			= {1, 1},
+	[FR_TYPE_UINT16]		= {2, 2},
+	[FR_TYPE_UINT32]		= {4, 4},
+	[FR_TYPE_UINT64]		= {8, 8},
+
+	[FR_TYPE_TLV]			= {2, ~0},
+	[FR_TYPE_STRUCT]		= {1, ~0},
+
+	[FR_TYPE_MAX]			= {~0, 0}	//!< Ensure array covers all types.
+};
+
 /*
  *	INADDR_ANY : 68 -> INADDR_BROADCAST : 67	DISCOVER
  *	INADDR_BROADCAST : 68 <- SERVER_IP : 67		OFFER
@@ -201,6 +226,48 @@ int8_t fr_dhcpv4_attr_cmp(void const *a, void const *b)
 	return fr_pair_cmp_by_parent_num(my_a, my_b);
 }
 
+/** Return the on-the-wire length of an attribute value
+ *
+ * @param[in] vp to return the length of.
+ * @return the length of the attribute.
+ */
+size_t fr_dhcpv4_option_len(fr_pair_t const *vp)
+{
+	switch (vp->vp_type) {
+	case FR_TYPE_VARIABLE_SIZE:
+#ifndef NDEBUG
+		if (!vp->da->flags.extra &&
+		    (vp->da->flags.subtype == FLAG_ENCODE_DNS_LABEL)) {
+			fr_assert_fail("DNS labels MUST be encoded/decoded with their own function, and not with generic 'string' functions");
+			return 0;
+		}
+#endif
+
+		if (vp->da->flags.length) return vp->da->flags.length;	/* Variable type with fixed length */
+
+		/*
+		 *	Arrays get maxed at 2^8 - 1
+		 */
+		if (vp->da->flags.array && ((vp->vp_type == FR_TYPE_STRING) || (vp->vp_type == FR_TYPE_OCTETS))) {
+			if (vp->vp_length > 255) return 255;
+		}
+
+		return vp->vp_length;
+
+	case FR_TYPE_DATE:
+	case FR_TYPE_TIME_DELTA:
+		if (vp->data.enumv->flags.length) return vp->data.enumv->flags.length;
+		return sizeof(uint32_t);
+
+	case FR_TYPE_STRUCTURAL:
+		fr_assert_fail(NULL);
+		return 0;
+
+	default:
+		return fr_dhcpv4_attr_sizes[vp->vp_type][0];
+	}
+}
+
 /** Check received DHCP request is valid and build fr_radius_packet_t structure if it is
  *
  * @param data pointer to received packet.
diff --git a/src/protocols/dhcpv4/dhcpv4.h b/src/protocols/dhcpv4/dhcpv4.h
index 7bf7cdd5d69..b2ed1b159c5 100644
--- a/src/protocols/dhcpv4/dhcpv4.h
+++ b/src/protocols/dhcpv4/dhcpv4.h
@@ -34,6 +34,8 @@ extern "C" {
 #include <freeradius-devel/util/packet.h>
 #include <freeradius-devel/protocol/dhcpv4/rfc2131.h>
 
+extern size_t const fr_dhcpv4_attr_sizes[FR_TYPE_MAX + 1][2];
+
 #define DHCP_CHADDR_LEN	(16)
 #define DHCP_SNAME_LEN	(64)
 #define DHCP_FILE_LEN	(128)
@@ -151,6 +153,7 @@ typedef struct {
  */
 int8_t		fr_dhcpv4_attr_cmp(void const *a, void const *b);
 
+size_t		fr_dhcpv4_option_len(fr_pair_t const *vp);
 bool		fr_dhcpv4_ok(uint8_t const *data, ssize_t data_len, uint8_t *message_type, uint32_t *xid);
 fr_radius_packet_t	*fr_dhcpv4_packet_alloc(uint8_t const *data, ssize_t data_len);
 bool 		fr_dhcpv4_is_encodable(void const *item, void const *uctx);