tidy dhcp

1 files changed, 157 insertions, 137 deletions

diff --git a/libdhcp/dhcp.c b/libdhcp/dhcp.c
index f55d224..ab3f4c9 100644
--- a/libdhcp/dhcp.c
+++ b/libdhcp/dhcp.c
@@ -67,132 +67,39 @@
 #include <string.h> /* for strlen(), memcpy(), memset() */
 
 #include <libmisc/endian.h>
+#include <libmisc/vcall.h>
 #include <libdhcp/dhcp.h>
 
-/* If you want to display debug & processing message, Define _DHCP_DEBUG_ in dhcp.h */
-
-#ifdef _DHCP_DEBUG_
-#	include <stdio.h>
-#	define debugf(fmt, ...) printf("> " fmt "\n" __VA_OPT__(,) __VA_ARGS__)
-#else
-#	define debugf(fmt, ...) ((void)0)
-#endif
-
-/* DHCP state machine. */
-#define STATE_DHCP_INIT          0        ///< Initialize
-#define STATE_DHCP_DISCOVER      1        ///< send DISCOVER and wait OFFER
-#define STATE_DHCP_REQUEST       2        ///< send REQEUST and wait ACK or NACK
-#define STATE_DHCP_LEASED        3        ///< ReceiveD ACK and IP leased
-#define STATE_DHCP_REREQUEST     4        ///< send REQUEST for maintaining leased IP
-#define STATE_DHCP_RELEASE       5        ///< No use
-#define STATE_DHCP_STOP          6        ///< Stop processing DHCP
-
-#define DHCP_FLAGSBROADCAST      0x8000   ///< The broadcast value of flags in @ref RIP_MSG
-#define DHCP_FLAGSUNICAST        0x0000   ///< The unicast   value of flags in @ref RIP_MSG
+/* Config *********************************************************************/
 
+#include "config.h"
 
-/**
- * https://www.iana.org/assignments/bootp-dhcp-parameters/bootp-dhcp-parameters.xhtml#message-type-53
- */
-#define DHCP_MSGTYP_DISCOVER     1
-#define DHCP_MSGTYP_OFFER        2
-#define DHCP_MSGTYP_REQUEST      3
-#define DHCP_MSGTYP_DECLINE      4
-#define DHCP_MSGTYP_ACK          5
-#define DHCP_MSGTYP_NAK          6
-#define DHCP_MSGTYP_RELEASE      7
-#define DHCP_MSGTYP_INFORM       8
-
-
-#define DHCP_HOPS                0        ///< Used in hops of @ref RIP_MSG
-#define DHCP_SECS                0        ///< Used in secs of @ref RIP_MSG
-
-#define INFINITE_LEASETIME       0xffffffff	///< Infinite lease time
-
+#ifndef CONFIG_DHCP_DEBUG
+#	define CONFIG_DHCP_DEBUG               1
+#endif
+#ifndef CONFIG_DHCP_HOPS
+#	define CONFIG_DHCP_HOPS                0
+#endif
+#ifndef CONFIG_DHCP_SECS
+#	define CONFIG_DHCP_SECS                0
+#endif
 #ifndef CONFIG_DHCP_OPT_SIZE
-#	define CONFIG_DHCP_OPT_SIZE                 312
+#	define CONFIG_DHCP_OPT_SIZE            312
 #endif
 
-/**
- * https://www.iana.org/assignments/bootp-dhcp-parameters/bootp-dhcp-parameters.xhtml
- */
-#define DHCP_OPT_PAD               ((uint8_t)  0) /* RFC2132: length: 0; meaning: None */
-#define DHCP_OPT_SUBNET_MASK       ((uint8_t)  1) /* RFC2132: length: 4; meaning: Subnet Mask Value */
-#define DHCP_OPT_TIME_OFFSET       ((uint8_t)  2) /* RFC2132: length: 4; meaning: Time Offset in Seconds from UTC (note: deprecated by 100 and 101 */
-#define DHCP_OPT_ROUTER            ((uint8_t)  3) /* RFC2132: length: N; meaning: N/4 Router addresses */
-#define DHCP_OPT_TIME_SERVER       ((uint8_t)  4) /* RFC2132: length: N; meaning: N/4 Timeserver addresses */
-#define DHCP_OPT_NAME_SERVER       ((uint8_t)  5) /* RFC2132: length: N; meaning: N/4 IEN-116 Server addresses */
-#define DHCP_OPT_DOMAIN_SERVER     ((uint8_t)  6) /* RFC2132: length: N; meaning: N/4 DNS Server addresses */
-#define DHCP_OPT_LOG_SERVER        ((uint8_t)  7) /* RFC2132: length: N; meaning: N/4 Logging Server addresses */
-#define DHCP_OPT_QUOTES_SERVER     ((uint8_t)  8) /* RFC2132: length: N; meaning: N/4 Quotes Server addresses */
-#define DHCP_OPT_LPR_SERVER        ((uint8_t)  9) /* RFC2132: length: N; meaning: N/4 Printer Server addresses */
-#define DHCP_OPT_IMPRESS_SERVER    ((uint8_t) 10) /* RFC2132: length: N; meaning: N/4 Impress Server addresses */
-#define DHCP_OPT_RLP_SERVER        ((uint8_t) 11) /* RFC2132: length: N; meaning: N/4 RLP Server addresses */
-#define DHCP_OPT_HOSTNAME          ((uint8_t) 12) /* RFC2132: length: N; meaning: Hostname string */
-#define DHCP_OPT_BOOT_FILE_SIZE    ((uint8_t) 13) /* RFC2132: length: 2; meaning: Size of boot file in 512 byte chunks */
-#define DHCP_OPT_MERIT_DUMP_FILE   ((uint8_t) 14) /* RFC2132: length: N; meaning: Client to dump and name the file to dump it to */
-#define DHCP_OPT_DOMAIN_NAME       ((uint8_t) 15) /* RFC2132: length: N; meaning: The DNS domain name of the client */
-#define DHCP_OPT_SWAP_SERVER       ((uint8_t) 16) /* RFC2132: length: N; meaning: Swap Server address */
-#define DHCP_OPT_ROOT_PATH         ((uint8_t) 17) /* RFC2132: length: N; meaning: Path name for root disk */
-#define DHCP_OPT_EXTENSION_FILE    ((uint8_t) 18) /* RFC2132: length: N; meaning: Path name for more BOOTP info */
-#define DHCP_OPT_FORWARD_ONOFF     ((uint8_t) 19) /* RFC2132: length: 1; meaning: Enable/Disable IP Forwarding */
-#define DHCP_OPT_SRCRTE_ONOFF      ((uint8_t) 20) /* RFC2132: length: 1; meaning: Enable/Disable Source Routing */
-#define DHCP_OPT_POLICY_FILTER     ((uint8_t) 21) /* RFC2132: length: N; meaning: Routing Policy Filters */
-#define DHCP_OPT_MAX_DG_ASSEMBLY   ((uint8_t) 22) /* RFC2132: length: 2; meaning: Max Datagram Reassembly Size */
-#define DHCP_OPT_DEFAULT_IP_TTL    ((uint8_t) 23) /* RFC2132: length: 1; meaning: Default IP Time to Live */
-#define DHCP_OPT_MTU_TIMEOUT       ((uint8_t) 24) /* RFC2132: length: 4; meaning: Path MTU Aging Timeout */
-#define DHCP_OPT_MTU_PLATEAU       ((uint8_t) 25) /* RFC2132: length: N; meaning: Path MTU Plateau Table */
-#define DHCP_OPT_MTU_INTERFACE     ((uint8_t) 26) /* RFC2132: length: 2; meaning: Interface MTU Size */
-#define DHCP_OPT_MTU_SUBNET        ((uint8_t) 27) /* RFC2132: length: 1; meaning: All Subnets are Local */
-#define DHCP_OPT_BROADCAST_ADDRESS ((uint8_t) 28) /* RFC2132: length: 4; meaning: Broadcast Address */
-#define DHCP_OPT_MASK_DISCOVERY    ((uint8_t) 29) /* RFC2132: length: 1; meaning: Perform Mask Discovery */
-#define DHCP_OPT_MASK_SUPPLIER     ((uint8_t) 30) /* RFC2132: length: 1; meaning: Provide Mask to Others */
-#define DHCP_OPT_ROUTER_DISCOVERY  ((uint8_t) 31) /* RFC2132: length: 1; meaning: Perform Router Discovery */
-#define DHCP_OPT_ROUTER_REQUEST    ((uint8_t) 32) /* RFC2132: length: 4; meaning: Router Solicitation Address */
-#define DHCP_OPT_STATIC_ROUTE      ((uint8_t) 33) /* RFC2132: length: N; meaning: Static Routing Table */
-#define DHCP_OPT_TRAILERS          ((uint8_t) 34) /* RFC2132: length: 1; meaning: Trailer Encapsulation */
-#define DHCP_OPT_ARP_TIMEOUT       ((uint8_t) 35) /* RFC2132: length: 4; meaning: ARP Cache Timeout */
-#define DHCP_OPT_ETHERNET          ((uint8_t) 36) /* RFC2132: length: 1; meaning: Ethernet Encapsulation */
-#define DHCP_OPT_DEFAULT_TCP_TTL   ((uint8_t) 37) /* RFC2132: length: 1; meaning: Default TCP Time to Live */
-#define DHCP_OPT_KEEPALIVE_TIME    ((uint8_t) 38) /* RFC2132: length: 4; meaning: TCP Keepalive Interval */
-#define DHCP_OPT_KEEPALIVE_DATA    ((uint8_t) 39) /* RFC2132: length: 1; meaning: TCP Keepalive Garbage */
-#define DHCP_OPT_NIS_DOMAIN        ((uint8_t) 40) /* RFC2132: length: N; meaning: NIS Domain Name */
-#define DHCP_OPT_NIS_SERVERS       ((uint8_t) 41) /* RFC2132: length: N; meaning: NIS Server Addresses */
-#define DHCP_OPT_NTP_SERVERS       ((uint8_t) 42) /* RFC2132: length: N; meaning: NTP Server Addresses */
-#define DHCP_OPT_VENDOR_SPECIFIC   ((uint8_t) 43) /* RFC2132: length: N; meaning: Vendor Specific Information */
-#define DHCP_OPT_NETBIOS_NAME_SRV  ((uint8_t) 44) /* RFC2132: length: N; meaning: NETBIOS Name Servers */
-#define DHCP_OPT_NETBIOS_DIST_SRV  ((uint8_t) 45) /* RFC2132: length: N; meaning: NETBIOS Datagram Distribution */
-#define DHCP_OPT_NETBIOS_NODE_TYPE ((uint8_t) 46) /* RFC2132: length: 1; meaning: NETBIOS Node Type */
-#define DHCP_OPT_NETBIOS_SCOPE     ((uint8_t) 47) /* RFC2132: length: N; meaning: NETBIOS Scope */
-#define DHCP_OPT_X_WINDOW_FONT     ((uint8_t) 48) /* RFC2132: length: N; meaning: X Window Font Server */
-#define DHCP_OPT_X_WINDOW_MANAGER  ((uint8_t) 49) /* RFC2132: length: N; meaning: X Window Display Manager */
-#define DHCP_OPT_ADDRESS_REQUEST   ((uint8_t) 50) /* RFC2132: length: 4; meaning: Requested IP Address */
-#define DHCP_OPT_ADDRESS_TIME      ((uint8_t) 51) /* RFC2132: length: 4; meaning: IP Address Lease Time */
-#define DHCP_OPT_OVERLOAD          ((uint8_t) 52) /* RFC2132: length: 1; meaning: Overload "sname" or "file */
-#define DHCP_OPT_DHCP_MSG_TYPE     ((uint8_t) 53) /* RFC2132: length: 1; meaning: DHCP Message Type */
-#define DHCP_OPT_DHCP_SERVER_ID    ((uint8_t) 54) /* RFC2132: length: 4; meaning: DHCP Server Identification */
-#define DHCP_OPT_PARAMETER_LIST    ((uint8_t) 55) /* RFC2132: length: N; meaning: Parameter Request List */
-#define DHCP_OPT_DHCP_MESSAGE      ((uint8_t) 56) /* RFC2132: length: N; meaning: DHCP Error Message */
-#define DHCP_OPT_DHCP_MAX_MSG_SIZE ((uint8_t) 57) /* RFC2132: length: 2; meaning: DHCP Maximum Message Size */
-#define DHCP_OPT_RENEWAL_TIME      ((uint8_t) 58) /* RFC2132: length: 4; meaning: DHCP Renewal (T1) Time */
-#define DHCP_OPT_REBINDING_TIME    ((uint8_t) 59) /* RFC2132: length: 4; meaning: DHCP Rebinding (T2) Time */
-#define DHCP_OPT_CLASS_ID          ((uint8_t) 60) /* RFC2132: length: N; meaning: Class Identifier */
-#define DHCP_OPT_CLIENT_ID         ((uint8_t) 61) /* RFC2132: length: N; meaning: Client Identifier */
-#define DHCP_OPT_END               ((uint8_t)255) /* RFC2132: length: 0; meaning: None */
+/* RFC 2131 definitions *******************************************************/
 
-/**
- * DHCP message.  See RFC 2131, figure 1 (page 9).
- */
+/** https://datatracker.ietf.org/doc/html/rfc2131#page-9 */
 struct dhcp_msg {
 	uint8_t                 op;         /* DHCP_OP_{x} */
 	uint8_t                 htype;      /* DHCP_HTYPE_{x} */
 	uint8_t                 hlen;       /* length of ->chaddr (`sizeof(struct net_eth_addr)`) */
-	uint8_t                 hops;       /* DHCP_HOPS */
+	uint8_t                 hops;
 
 	uint32be_t              xid;        /* `global_xid`; this increase one every DHCP transaction */
 
-	uint16be_t              secs;       /* DHCP_SECS */
-	uint16be_t              flags;      /* DHCP_FLAGSBROADCAST or @ref DHCP_FLAGSUNICAST */
+	uint16be_t              secs;
+	uint16be_t              flags;      /* DHCP_FLAG_{x} */
 
 	struct net_ip4_addr     ciaddr;     /* Request IP to DHCP sever */
 	struct net_ip4_addr     yiaddr;     /* Offered IP from DHCP server */
@@ -205,26 +112,142 @@ struct dhcp_msg {
 	uint8_t                 options[CONFIG_DHCP_OPT_SIZE];
 };
 static_assert(offsetof(struct dhcp_msg, options) == 236);
-#define DHCP_MSG_BASE_SIZE offsetof(struct dhcp_msg, options)
+#define DHCP_MSG_BASE_SIZE       offsetof(struct dhcp_msg, options)
 
-/* DHCP message OP code; RFC 2131 page 10*/
-#define DHCP_OP_BOOTREQUEST         1
-#define DHCP_OP_BOOTREPLY           2
+/** https://datatracker.ietf.org/doc/html/rfc2131#page-10 */
+#define DHCP_OP_BOOTREQUEST      1
+#define DHCP_OP_BOOTREPLY        2
+
+/** https://datatracker.ietf.org/doc/html/rfc2131#page-11 */
+#define DHCP_FLAG_BROADCAST      0x8000
+
+/** https://datatracker.ietf.org/doc/html/rfc2131#section-3 */
+#define DHCP_MAGIC_COOKIE        ((uint8_t[]){99, 130, 83, 99})
+
+/** https://datatracker.ietf.org/doc/html/rfc2131#section-3.3 */
+#define DHCP_INFINITY            0xffffffff
+
+/* IANA assignments ***********************************************************/
+
+/**
+ * Port Numbers
+ * https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml
+ */
+#define DHCP_PORT_SERVER                ((uint16_t)67)
+#define DHCP_PORT_CLIENT                ((uint16_t)68)
 
 /**
- * DHCP hardware type;
+ * Hardware Types
  * https://www.iana.org/assignments/arp-parameters/arp-parameters.xhtml#arp-parameters-2
  */
-#define DHCP_HTYPE_ETHERNET         1
+#define DHCP_HTYPE_ETHERNET             ((uint8_t)  1)
+
+/**
+ * DHCP Options
+ * https://www.iana.org/assignments/bootp-dhcp-parameters/bootp-dhcp-parameters.xhtml#options
+ */
+#define DHCP_OPT_PAD                    ((uint8_t)  0) /* RFC2132: length: 0; meaning: None */
+#define DHCP_OPT_SUBNET_MASK            ((uint8_t)  1) /* RFC2132: length: 4; meaning: Subnet Mask Value */
+#define DHCP_OPT_TIME_OFFSET            ((uint8_t)  2) /* RFC2132: length: 4; meaning: Time Offset in Seconds from UTC (note: deprecated by 100 and 101 */
+#define DHCP_OPT_ROUTER                 ((uint8_t)  3) /* RFC2132: length: N; meaning: N/4 Router addresses */
+#define DHCP_OPT_TIME_SERVER            ((uint8_t)  4) /* RFC2132: length: N; meaning: N/4 Timeserver addresses */
+#define DHCP_OPT_NAME_SERVER            ((uint8_t)  5) /* RFC2132: length: N; meaning: N/4 IEN-116 Server addresses */
+#define DHCP_OPT_DOMAIN_SERVER          ((uint8_t)  6) /* RFC2132: length: N; meaning: N/4 DNS Server addresses */
+#define DHCP_OPT_LOG_SERVER             ((uint8_t)  7) /* RFC2132: length: N; meaning: N/4 Logging Server addresses */
+#define DHCP_OPT_QUOTES_SERVER          ((uint8_t)  8) /* RFC2132: length: N; meaning: N/4 Quotes Server addresses */
+#define DHCP_OPT_LPR_SERVER             ((uint8_t)  9) /* RFC2132: length: N; meaning: N/4 Printer Server addresses */
+#define DHCP_OPT_IMPRESS_SERVER         ((uint8_t) 10) /* RFC2132: length: N; meaning: N/4 Impress Server addresses */
+#define DHCP_OPT_RLP_SERVER             ((uint8_t) 11) /* RFC2132: length: N; meaning: N/4 RLP Server addresses */
+#define DHCP_OPT_HOSTNAME               ((uint8_t) 12) /* RFC2132: length: N; meaning: Hostname string */
+#define DHCP_OPT_BOOT_FILE_SIZE         ((uint8_t) 13) /* RFC2132: length: 2; meaning: Size of boot file in 512 byte chunks */
+#define DHCP_OPT_MERIT_DUMP_FILE        ((uint8_t) 14) /* RFC2132: length: N; meaning: Client to dump and name the file to dump it to */
+#define DHCP_OPT_DOMAIN_NAME            ((uint8_t) 15) /* RFC2132: length: N; meaning: The DNS domain name of the client */
+#define DHCP_OPT_SWAP_SERVER            ((uint8_t) 16) /* RFC2132: length: N; meaning: Swap Server address */
+#define DHCP_OPT_ROOT_PATH              ((uint8_t) 17) /* RFC2132: length: N; meaning: Path name for root disk */
+#define DHCP_OPT_EXTENSION_FILE         ((uint8_t) 18) /* RFC2132: length: N; meaning: Path name for more BOOTP info */
+#define DHCP_OPT_FORWARD_ONOFF          ((uint8_t) 19) /* RFC2132: length: 1; meaning: Enable/Disable IP Forwarding */
+#define DHCP_OPT_SRCRTE_ONOFF           ((uint8_t) 20) /* RFC2132: length: 1; meaning: Enable/Disable Source Routing */
+#define DHCP_OPT_POLICY_FILTER          ((uint8_t) 21) /* RFC2132: length: N; meaning: Routing Policy Filters */
+#define DHCP_OPT_MAX_DG_ASSEMBLY        ((uint8_t) 22) /* RFC2132: length: 2; meaning: Max Datagram Reassembly Size */
+#define DHCP_OPT_DEFAULT_IP_TTL         ((uint8_t) 23) /* RFC2132: length: 1; meaning: Default IP Time to Live */
+#define DHCP_OPT_MTU_TIMEOUT            ((uint8_t) 24) /* RFC2132: length: 4; meaning: Path MTU Aging Timeout */
+#define DHCP_OPT_MTU_PLATEAU            ((uint8_t) 25) /* RFC2132: length: N; meaning: Path MTU Plateau Table */
+#define DHCP_OPT_MTU_INTERFACE          ((uint8_t) 26) /* RFC2132: length: 2; meaning: Interface MTU Size */
+#define DHCP_OPT_MTU_SUBNET             ((uint8_t) 27) /* RFC2132: length: 1; meaning: All Subnets are Local */
+#define DHCP_OPT_BROADCAST_ADDRESS      ((uint8_t) 28) /* RFC2132: length: 4; meaning: Broadcast Address */
+#define DHCP_OPT_MASK_DISCOVERY         ((uint8_t) 29) /* RFC2132: length: 1; meaning: Perform Mask Discovery */
+#define DHCP_OPT_MASK_SUPPLIER          ((uint8_t) 30) /* RFC2132: length: 1; meaning: Provide Mask to Others */
+#define DHCP_OPT_ROUTER_DISCOVERY       ((uint8_t) 31) /* RFC2132: length: 1; meaning: Perform Router Discovery */
+#define DHCP_OPT_ROUTER_REQUEST         ((uint8_t) 32) /* RFC2132: length: 4; meaning: Router Solicitation Address */
+#define DHCP_OPT_STATIC_ROUTE           ((uint8_t) 33) /* RFC2132: length: N; meaning: Static Routing Table */
+#define DHCP_OPT_TRAILERS               ((uint8_t) 34) /* RFC2132: length: 1; meaning: Trailer Encapsulation */
+#define DHCP_OPT_ARP_TIMEOUT            ((uint8_t) 35) /* RFC2132: length: 4; meaning: ARP Cache Timeout */
+#define DHCP_OPT_ETHERNET               ((uint8_t) 36) /* RFC2132: length: 1; meaning: Ethernet Encapsulation */
+#define DHCP_OPT_DEFAULT_TCP_TTL        ((uint8_t) 37) /* RFC2132: length: 1; meaning: Default TCP Time to Live */
+#define DHCP_OPT_KEEPALIVE_TIME         ((uint8_t) 38) /* RFC2132: length: 4; meaning: TCP Keepalive Interval */
+#define DHCP_OPT_KEEPALIVE_DATA         ((uint8_t) 39) /* RFC2132: length: 1; meaning: TCP Keepalive Garbage */
+#define DHCP_OPT_NIS_DOMAIN             ((uint8_t) 40) /* RFC2132: length: N; meaning: NIS Domain Name */
+#define DHCP_OPT_NIS_SERVERS            ((uint8_t) 41) /* RFC2132: length: N; meaning: NIS Server Addresses */
+#define DHCP_OPT_NTP_SERVERS            ((uint8_t) 42) /* RFC2132: length: N; meaning: NTP Server Addresses */
+#define DHCP_OPT_VENDOR_SPECIFIC        ((uint8_t) 43) /* RFC2132: length: N; meaning: Vendor Specific Information */
+#define DHCP_OPT_NETBIOS_NAME_SRV       ((uint8_t) 44) /* RFC2132: length: N; meaning: NETBIOS Name Servers */
+#define DHCP_OPT_NETBIOS_DIST_SRV       ((uint8_t) 45) /* RFC2132: length: N; meaning: NETBIOS Datagram Distribution */
+#define DHCP_OPT_NETBIOS_NODE_TYPE      ((uint8_t) 46) /* RFC2132: length: 1; meaning: NETBIOS Node Type */
+#define DHCP_OPT_NETBIOS_SCOPE          ((uint8_t) 47) /* RFC2132: length: N; meaning: NETBIOS Scope */
+#define DHCP_OPT_X_WINDOW_FONT          ((uint8_t) 48) /* RFC2132: length: N; meaning: X Window Font Server */
+#define DHCP_OPT_X_WINDOW_MANAGER       ((uint8_t) 49) /* RFC2132: length: N; meaning: X Window Display Manager */
+#define DHCP_OPT_ADDRESS_REQUEST        ((uint8_t) 50) /* RFC2132: length: 4; meaning: Requested IP Address */
+#define DHCP_OPT_ADDRESS_TIME           ((uint8_t) 51) /* RFC2132: length: 4; meaning: IP Address Lease Time */
+#define DHCP_OPT_OVERLOAD               ((uint8_t) 52) /* RFC2132: length: 1; meaning: Overload "sname" or "file */
+#define DHCP_OPT_DHCP_MSG_TYPE          ((uint8_t) 53) /* RFC2132: length: 1; meaning: DHCP Message Type */
+#define DHCP_OPT_DHCP_SERVER_ID         ((uint8_t) 54) /* RFC2132: length: 4; meaning: DHCP Server Identification */
+#define DHCP_OPT_PARAMETER_LIST         ((uint8_t) 55) /* RFC2132: length: N; meaning: Parameter Request List */
+#define DHCP_OPT_DHCP_MESSAGE           ((uint8_t) 56) /* RFC2132: length: N; meaning: DHCP Error Message */
+#define DHCP_OPT_DHCP_MAX_MSG_SIZE      ((uint8_t) 57) /* RFC2132: length: 2; meaning: DHCP Maximum Message Size */
+#define DHCP_OPT_RENEWAL_TIME           ((uint8_t) 58) /* RFC2132: length: 4; meaning: DHCP Renewal (T1) Time */
+#define DHCP_OPT_REBINDING_TIME         ((uint8_t) 59) /* RFC2132: length: 4; meaning: DHCP Rebinding (T2) Time */
+#define DHCP_OPT_CLASS_ID               ((uint8_t) 60) /* RFC2132: length: N; meaning: Class Identifier */
+#define DHCP_OPT_CLIENT_ID              ((uint8_t) 61) /* RFC2132: length: N; meaning: Client Identifier */
+#define DHCP_OPT_END                    ((uint8_t)255) /* RFC2132: length: 0; meaning: None */
+
+/**
+ * DHCP Message Type 53 Values
+ * https://www.iana.org/assignments/bootp-dhcp-parameters/bootp-dhcp-parameters.xhtml#message-type-53
+ */
+#define DHCP_MSGTYP_DISCOVER            ((uint8_t)  1) /* RFC2132 */
+#define DHCP_MSGTYP_OFFER               ((uint8_t)  2) /* RFC2132 */
+#define DHCP_MSGTYP_REQUEST             ((uint8_t)  3) /* RFC2132 */
+#define DHCP_MSGTYP_DECLINE             ((uint8_t)  4) /* RFC2132 */
+#define DHCP_MSGTYP_ACK                 ((uint8_t)  5) /* RFC2132 */
+#define DHCP_MSGTYP_NAK                 ((uint8_t)  6) /* RFC2132 */
+#define DHCP_MSGTYP_RELEASE             ((uint8_t)  7) /* RFC2132 */
+#define DHCP_MSGTYP_INFORM              ((uint8_t)  8) /* RFC2132 */
+
+/******************************************************************************/
+
+#if CONFIG_DHCP_DEBUG
+#	include <stdio.h>
+#	define debugf(fmt, ...) printf(fmt "\n" __VA_OPT__(,) __VA_ARGS__)
+#else
+#	define debugf(fmt, ...) ((void)0)
+#endif
+
+/* DHCP state machine.  */
+#define STATE_DHCP_INIT          0        ///< Initialize
+#define STATE_DHCP_DISCOVER      1        ///< send DISCOVER and wait OFFER
+#define STATE_DHCP_REQUEST       2        ///< send REQEUST and wait ACK or NACK
+#define STATE_DHCP_LEASED        3        ///< ReceiveD ACK and IP leased
+#define STATE_DHCP_REREQUEST     4        ///< send REQUEST for maintaining leased IP
+#define STATE_DHCP_RELEASE       5        ///< No use
+#define STATE_DHCP_STOP          6        ///< Stop processing DHCP
 
 struct net_ip4_addr DHCP_SIP;                      // DHCP Server IP address
 struct net_ip4_addr DHCP_REAL_SIP;                 // For extract my DHCP server in a few DHCP server
 
-
 // Network information from DHCP Server
 struct net_ip4_addr OLD_allocated_ip   = {0};    // Previous IP address
 struct dhcp_lease global_lease = {
-	.lifetime = INFINITE_LEASETIME,
+	.lifetime = DHCP_INFINITY,
 };
 
 int8_t   dhcp_state        = STATE_DHCP_INIT;   // DHCP state
@@ -272,10 +295,10 @@ void dhcp_msg_init(struct dhcp_msg *msg, size_t *optlen) {
 	msg->op     = DHCP_OP_BOOTREQUEST;
 	msg->htype  = DHCP_HTYPE_ETHERNET;
 	msg->hlen   = sizeof(global_eth_addr);
-	msg->hops   = DHCP_HOPS;
+	msg->hops   = CONFIG_DHCP_HOPS;
 	msg->xid    = uint32be_marshal(global_xid);
-	msg->secs   = uint16be_marshal(DHCP_SECS);
-	msg->flags  = uint16be_marshal(DHCP_FLAGSBROADCAST);
+	msg->secs   = uint16be_marshal(CONFIG_DHCP_SECS);
+	msg->flags  = uint16be_marshal(DHCP_FLAG_BROADCAST);
 	msg->ciaddr = (struct net_ip4_addr){0};
 	msg->yiaddr = (struct net_ip4_addr){0};
 	msg->siaddr = (struct net_ip4_addr){0};
@@ -288,8 +311,7 @@ void dhcp_msg_init(struct dhcp_msg *msg, size_t *optlen) {
 	memset(msg->sname, 0, sizeof(msg->sname));
 	memset(msg->file, 0, sizeof(msg->file));
 
-	*optlen = 0;
-	uint32be_encode(&msg->options[*optlen], MAGIC_COOKIE); *optlen += 4;
+	*optlen = mem_encode(msg->options, DHCP_MAGIC_COOKIE);
 }
 
 /* SEND DHCP DISCOVER */
@@ -331,7 +353,7 @@ void send_DHCP_DISCOVER(implements_net_udpsock *sock) {
 
 	debugf("> Send DHCP_DISCOVER");
 	assert(k <= CONFIG_DHCP_OPT_SIZE);
-	sendto(sock, pDHCPMSG, DHCP_MSG_BASE_SIZE + k, net_ip4_addr_broadcast, DHCP_SERVER_PORT);
+	sendto(sock, pDHCPMSG, DHCP_MSG_BASE_SIZE + k, net_ip4_addr_broadcast, DHCP_PORT_SERVER);
 }
 
 /* SEND DHCP REQUEST */
@@ -344,7 +366,7 @@ void send_DHCP_REQUEST(implements_net_udpsock *sock) {
 	switch (dhcp_state) {
 	case STATE_DHCP_LEASED:
 	case STATE_DHCP_REREQUEST:
-		pDHCPMSG->flags = uint16be_marshal(DHCP_FLAGSUNICAST);
+		pDHCPMSG->flags = uint16be_marshal(0);
 		pDHCPMSG->ciaddr = global_lease.addr;
 		ip = DHCP_SIP;
 		break;
@@ -399,7 +421,7 @@ void send_DHCP_REQUEST(implements_net_udpsock *sock) {
 
 	debugf("> Send DHCP_REQUEST");
 	assert(k <= CONFIG_DHCP_OPT_SIZE);
-	sendto(sock, pDHCPMSG, DHCP_MSG_BASE_SIZE + k, ip, DHCP_SERVER_PORT);
+	sendto(sock, pDHCPMSG, DHCP_MSG_BASE_SIZE + k, ip, DHCP_PORT_SERVER);
 }
 
 /* SEND DHCP DHCPDECLINE */
@@ -407,9 +429,7 @@ void send_DHCP_DECLINE(implements_net_udpsock *sock) {
 	size_t k;
 
 	dhcp_msg_init(pDHCPMSG, &k);
-
-	*((uint8_t*)(&pDHCPMSG->flags))   = ((DHCP_FLAGSUNICAST & 0xFF00)>> 8);
-	*((uint8_t*)(&pDHCPMSG->flags)+1) = (DHCP_FLAGSUNICAST & 0x00FF);
+	pDHCPMSG->flags = uint16be_marshal(0);
 
 	// Option Request Param.
 	pDHCPMSG->options[k++] = DHCP_OPT_DHCP_MSG_TYPE;
@@ -438,7 +458,7 @@ void send_DHCP_DECLINE(implements_net_udpsock *sock) {
 
 	debugf("> Send DHCP_DECLINE");
 	assert(k <= CONFIG_DHCP_OPT_SIZE);
-	sendto(sock, pDHCPMSG, DHCP_MSG_BASE_SIZE + k, net_ip4_addr_broadcast, DHCP_SERVER_PORT);
+	sendto(sock, pDHCPMSG, DHCP_MSG_BASE_SIZE + k, net_ip4_addr_broadcast, DHCP_PORT_SERVER);
 }
 
 /* PARSE REPLY pDHCPMSG */
@@ -450,7 +470,7 @@ int8_t dhcp_msg_parse(implements_net_udpsock *sock) {
 	debugf("DHCP message : %d.%d.%d.%d(%d) %d received.",
 	       srv_addr.octets[0], srv_addr.octets[1], srv_addr.octets[2], srv_addr.octets[3], srv_port, len);
 	/* Compare server port.  */
-	if (srv_port != DHCP_SERVER_PORT) {
+	if (srv_port != DHCP_PORT_SERVER) {
 		return 0;
 	}
 	/* Compare our MAC address.  */
@@ -515,7 +535,7 @@ int8_t dhcp_msg_parse(implements_net_udpsock *sock) {
 			if (opt_len != 4)
 				continue;
 			global_lease.lifetime = uint32be_decode(&pDHCPMSG->options[k]);
-#ifdef _DHCP_DEBUG_
+#if CONFIG_DHCP_DEBUG
 			global_lease.lifetime = 10;
 #endif
 			break;
@@ -541,7 +561,7 @@ uint8_t DHCP_run(implements_net_udpsock *sock, dhcp_callback_t cb) {
 		return DHCP_RET_STOPPED;
 
 	if (getSn_SR(sock) != SOCK_UDP)
-		socket(sock, Sn_MR_UDP, DHCP_CLIENT_PORT, 0);
+		socket(sock, Sn_MR_UDP, DHCP_PORT_CLIENT, 0);
 
 	ret = DHCP_RET_RUNNING;
 	msg_type = dhcp_msg_parse(sock);
@@ -593,7 +613,7 @@ uint8_t DHCP_run(implements_net_udpsock *sock, dhcp_callback_t cb) {
 
 	case STATE_DHCP_LEASED :
 		ret = DHCP_RET_IP_LEASED;
-		if ((global_lease.lifetime != INFINITE_LEASETIME) && ((global_lease.lifetime/2) < dhcp_tick_1s)) {
+		if ((global_lease.lifetime != DHCP_INFINITY) && ((global_lease.lifetime/2) < dhcp_tick_1s)) {
 			debugf("> Maintains the IP address");
 
 			msg_type = 0;
@@ -681,7 +701,7 @@ uint8_t check_DHCP_timeout(implements_net_udpsock *sock) {
 			break;
 		case STATE_DHCP_REQUEST:
 		case STATE_DHCP_REREQUEST:
-			send_DHCP_DISCOVER();
+			send_DHCP_DISCOVER(sock);
 			dhcp_state = STATE_DHCP_DISCOVER;
 			break;
 		default :
@@ -715,7 +735,7 @@ int8_t check_DHCP_leasedIP(implements_net_udpsock *sock) {
 		return 1;
 	} else {
 		// Received ARP reply or etc : IP address conflict occur, DHCP Failed
-		send_DHCP_DECLINE();
+		send_DHCP_DECLINE(sock);
 
 		ret = dhcp_tick_1s;
 		while((dhcp_tick_1s - ret) < 2) ;   // wait for 1s over; wait to complete to send DECLINE message;