/* libdhcp/dhcp_common.h - Base definitions for the DHCP protocol
*
* Copyright (C) 2024 Luke T. Shumaker <lukeshu@lukeshu.com>
* SPDX-License-Identifier: AGPL-3.0-or-later
*
* -----------------------------------------------------------------------------
* https://github.com/Wiznet/ioLibrary_Driver/blob/b981401e7f3d07015619adf44c13998e13e777f9/Internet/DHCP/dhcp.c
*
* Copyright (c) 2013, WIZnet Co., LTD.
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* -----------------------------------------------------------------------------
* https://github.com/Wiznet/ioLibrary_Driver/blob/b981401e7f3d07015619adf44c13998e13e777f9/license.txt
*
* Copyright (c) 2014 WIZnet Co.,Ltd.
* Copyright (c) WIZnet ioLibrary Project.
* All rights reserved.
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*/
#ifndef _LIBDHCP_DHCP_COMMON_H_
#define _LIBDHCP_DHCP_COMMON_H_
#include <libmisc/endian.h>
#include <libmisc/log.h> /* for const_byte_str() */
/* Config *********************************************************************/
#include "config.h"
#ifndef CONFIG_DHCP_OPT_SIZE
#error config.h must define CONFIG_DHCP_OPT_SIZE (minimum 312)
#endif
/* RFC 2131 definitions *******************************************************/
/**
* "A DHCP client must be prepared to receive DHCP messages with an
* 'options' field of at least length 312 octets." --
* https://datatracker.ietf.org/doc/html/rfc2131#page-9
*/
#define DHCP_MSG_MIN_MAX_OPT_SIZE 312
static_assert(CONFIG_DHCP_OPT_SIZE >= DHCP_MSG_MIN_MAX_OPT_SIZE);
/** 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;
uint32be_t xid; /* transaction ID */
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 */
struct net_ip4_addr siaddr; /* next-server IP address */
struct net_ip4_addr giaddr; /* relay-agent IP address */
uint8_t chaddr[16]; /* client hardware (MAC) address */
uint8_t sname[64]; /* server name (not used) */
uint8_t file[128]; /* boot file name (not used) */
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)
/** 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 /* The BROADCAST flag (set by the client)
* indicates that the server should use
* broadcast-IP replies instead of
* unicast-IP because the client is not
* yet capable of receiving unicast-IP at
* this stage of configuration. */
/** https://datatracker.ietf.org/doc/html/rfc2131#section-3 */
static const uint8_t dhcp_magic_cookie[] = {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)
/**
* Hardware Types
* https://www.iana.org/assignments/arp-parameters/arp-parameters.xhtml#arp-parameters-2
*/
#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 */ /* note: includes IP & UDP headers (20 and 8, respectively) */
#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 */
static inline bool dhcp_opt_length_is_valid(uint8_t opt, uint16_t len) {
switch (opt) {
/* RFC 2132 */
case DHCP_OPT_PAD: return len == 0;
case DHCP_OPT_SUBNET_MASK: return len == 4;
case DHCP_OPT_TIME_OFFSET: return len == 4;
case DHCP_OPT_ROUTER: return len >= 4 && len % 4 == 0;
case DHCP_OPT_TIME_SERVER: return len >= 4 && len % 4 == 0;
case DHCP_OPT_NAME_SERVER: return len >= 4 && len % 4 == 0;
case DHCP_OPT_DOMAIN_SERVER: return len >= 4 && len % 4 == 0;
case DHCP_OPT_LOG_SERVER: return len >= 4 && len % 4 == 0;
case DHCP_OPT_QUOTES_SERVER: return len >= 4 && len % 4 == 0;
case DHCP_OPT_LPR_SERVER: return len >= 4 && len % 4 == 0;
case DHCP_OPT_IMPRESS_SERVER: return len >= 4 && len % 4 == 0;
case DHCP_OPT_RLP_SERVER: return len >= 4 && len % 4 == 0;
case DHCP_OPT_HOSTNAME: return len >= 1;
case DHCP_OPT_BOOT_FILE_SIZE: return len == 2;
case DHCP_OPT_MERIT_DUMP_FILE: return len >= 1;
case DHCP_OPT_DOMAIN_NAME: return len >= 1;
case DHCP_OPT_SWAP_SERVER: return len == 4; /* IANA says length is "N", but RFC 2132 says "length is 4"; likely releated to errata ID 487 */
case DHCP_OPT_ROOT_PATH: return len >= 1;
case DHCP_OPT_EXTENSION_FILE: return len >= 1;
case DHCP_OPT_FORWARD_ONOFF: return len == 1;
case DHCP_OPT_SRCRTE_ONOFF: return len == 1;
case DHCP_OPT_POLICY_FILTER: return len >= 8 && len % 8 == 0;
case DHCP_OPT_MAX_DG_ASSEMBLY: return len == 2;
case DHCP_OPT_DEFAULT_IP_TTL: return len == 1;
case DHCP_OPT_MTU_TIMEOUT: return len == 4;
case DHCP_OPT_MTU_PLATEAU: return len >= 2 && len % 2 == 0;
case DHCP_OPT_MTU_INTERFACE: return len == 2;
case DHCP_OPT_MTU_SUBNET: return len == 1;
case DHCP_OPT_BROADCAST_ADDRESS: return len == 4;
case DHCP_OPT_MASK_DISCOVERY: return len == 1;
case DHCP_OPT_MASK_SUPPLIER: return len == 1;
case DHCP_OPT_ROUTER_DISCOVERY: return len == 1;
case DHCP_OPT_ROUTER_REQUEST: return len == 4;
case DHCP_OPT_STATIC_ROUTE: return len >= 8 && len % 8 == 0;
case DHCP_OPT_TRAILERS: return len == 1;
case DHCP_OPT_ARP_TIMEOUT: return len == 4;
case DHCP_OPT_ETHERNET: return len == 1;
case DHCP_OPT_DEFAULT_TCP_TTL: return len == 1;
case DHCP_OPT_KEEPALIVE_TIME: return len == 4;
case DHCP_OPT_KEEPALIVE_DATA: return len == 1;
case DHCP_OPT_NIS_DOMAIN: return len >= 1;
case DHCP_OPT_NIS_SERVERS: return len >= 4 && len % 4 == 0;
case DHCP_OPT_NTP_SERVERS: return len >= 4 && len % 4 == 0;
case DHCP_OPT_VENDOR_SPECIFIC: return len >= 1;
case DHCP_OPT_NETBIOS_NAME_SRV: return len >= 4 && len % 4 == 0;
case DHCP_OPT_NETBIOS_DIST_SRV: return len >= 4 && len % 4 == 0;
case DHCP_OPT_NETBIOS_NODE_TYPE: return len == 1;
case DHCP_OPT_NETBIOS_SCOPE: return len >= 1;
case DHCP_OPT_X_WINDOW_FONT: return len >= 4 && len % 4 == 0;
case DHCP_OPT_X_WINDOW_MANAGER: return len >= 4 && len % 4 == 0;
case DHCP_OPT_ADDRESS_REQUEST: return len == 4;
case DHCP_OPT_ADDRESS_TIME: return len == 4;
case DHCP_OPT_OVERLOAD: return len == 1;
case DHCP_OPT_DHCP_MSG_TYPE: return len == 1;
case DHCP_OPT_DHCP_SERVER_ID: return len == 4;
case DHCP_OPT_PARAMETER_LIST: return len >= 1;
case DHCP_OPT_DHCP_MESSAGE: return len >= 1;
case DHCP_OPT_DHCP_MAX_MSG_SIZE: return len == 2;
case DHCP_OPT_RENEWAL_TIME: return len == 4;
case DHCP_OPT_REBINDING_TIME: return len == 4;
case DHCP_OPT_CLASS_ID: return len >= 1;
case DHCP_OPT_CLIENT_ID: return len >= 2;
/* RFC 2132 */
case DHCP_OPT_END: return len == 0;
/* Unrecognized */
default:
return true;
}
};
/**
* 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, client->server */
#define DHCP_MSGTYP_OFFER ((uint8_t) 2) /* RFC2132, server->client */
#define DHCP_MSGTYP_REQUEST ((uint8_t) 3) /* RFC2132, client->server */
#define DHCP_MSGTYP_DECLINE ((uint8_t) 4) /* RFC2132, client->server */
#define DHCP_MSGTYP_ACK ((uint8_t) 5) /* RFC2132, server->client */
#define DHCP_MSGTYP_NAK ((uint8_t) 6) /* RFC2132, server->client */
#define DHCP_MSGTYP_RELEASE ((uint8_t) 7) /* RFC2132, client->server */
#define DHCP_MSGTYP_INFORM ((uint8_t) 8) /* RFC2132, client->server */
static const char *dhcp_msgtyp_str(uint8_t typ) {
switch (typ) {
case DHCP_MSGTYP_DISCOVER: return "DHCP_MSGTYP_DISCOVER";
case DHCP_MSGTYP_OFFER: return "DHCP_MSGTYP_OFFER";
case DHCP_MSGTYP_REQUEST: return "DHCP_MSGTYP_REQUEST";
case DHCP_MSGTYP_DECLINE: return "DHCP_MSGTYP_DECLINE";
case DHCP_MSGTYP_ACK: return "DHCP_MSGTYP_ACK";
case DHCP_MSGTYP_NAK: return "DHCP_MSGTYP_NAK";
case DHCP_MSGTYP_RELEASE: return "DHCP_MSGTYP_RELEASE";
case DHCP_MSGTYP_INFORM: return "DHCP_MSGTYP_INFORM";
default: return const_byte_str(typ);
}
}
#endif /* _LIBDHCP_DHCP_COMMON_H_ */