networking/udhcp/common.h

/* vi: set sw=4 ts=4: */
/* common.h
 *
 * Russ Dill <Russ.Dill@asu.edu> September 2001
 * Rewritten by Vladimir Oleynik <dzo@simtreas.ru> (C) 2003
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */
#ifndef UDHCP_COMMON_H
#define UDHCP_COMMON_H 1

#include "libbb.h"
#include <netinet/udp.h>
#include <netinet/ip.h>

PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN

#define DEFAULT_SCRIPT   CONFIG_UDHCPC_DEFAULT_SCRIPT

extern const uint8_t MAC_BCAST_ADDR[6]; /* six all-ones */

/*** packet.h ***/

/* DHCP protocol. See RFC 2131 */
#define DHCP_MAGIC              0x63825363

#define DHCP_OPTIONS_BUFSIZE    308

#define BOOTREQUEST             1
#define BOOTREPLY               2

//TODO: rename ciaddr/yiaddr/chaddr
struct dhcp_packet {
	uint8_t op;      /* BOOTREQUEST or BOOTREPLY */
	uint8_t htype;   /* hardware address type. 1 = 10mb ethernet */
	uint8_t hlen;    /* hardware address length */
	uint8_t hops;    /* used by relay agents only */
	uint32_t xid;    /* unique id */
	uint16_t secs;   /* elapsed since client began acquisition/renewal */
	uint16_t flags;  /* only one flag so far: */
#define BROADCAST_FLAG 0x8000 /* "I need broadcast replies" */
	uint32_t ciaddr; /* client IP (if client is in BOUND, RENEW or REBINDING state) */
	uint32_t yiaddr; /* 'your' (client) IP address */
	/* IP address of next server to use in bootstrap, returned in DHCPOFFER, DHCPACK by server */
	uint32_t siaddr_nip;
	uint32_t gateway_nip; /* relay agent IP address */
	uint8_t chaddr[16];   /* link-layer client hardware address (MAC) */
	uint8_t sname[64];    /* server host name (ASCIZ) */
	uint8_t file[128];    /* boot file name (ASCIZ) */
	uint32_t cookie;      /* fixed first four option bytes (99,130,83,99 dec) */
	uint8_t options[DHCP_OPTIONS_BUFSIZE + CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS];
} PACKED;
#define DHCP_PKT_SNAME_LEN      64
#define DHCP_PKT_FILE_LEN      128
#define DHCP_PKT_SNAME_LEN_STR "64"
#define DHCP_PKT_FILE_LEN_STR "128"

struct ip_udp_dhcp_packet {
	struct iphdr ip;
	struct udphdr udp;
	struct dhcp_packet data;
} PACKED;

/* Let's see whether compiler understood us right */
struct BUG_bad_sizeof_struct_ip_udp_dhcp_packet {
	char BUG_bad_sizeof_struct_ip_udp_dhcp_packet
		[(sizeof(struct ip_udp_dhcp_packet) != 576 + CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS) ? -1 : 1];
};

// RFC 2131  Table 5: Fields and options used by DHCP clients
//
// Field      DHCPDISCOVER          DHCPREQUEST           DHCPDECLINE,
//            DHCPINFORM                                  DHCPRELEASE
// -----      ------------          -----------           -----------
// 'op'       BOOTREQUEST           BOOTREQUEST           BOOTREQUEST
// 'hops'     0                     0                     0
// 'xid'      selected by client    'xid' from server     selected by
//                                  DHCPOFFER message     client
// 'secs'     0 or seconds since    0 or seconds since    0
//            DHCP process started  DHCP process started
// 'flags'    Set 'BROADCAST'       Set 'BROADCAST'       0
//            flag if client        flag if client
//            requires broadcast    requires broadcast
//            reply                 reply
// 'ciaddr'   0 (DHCPDISCOVER)      0 or client's         0 (DHCPDECLINE)
//            client's              network address       client's network
//            network address       (BOUND/RENEW/REBIND)  address
//            (DHCPINFORM)                                (DHCPRELEASE)
// 'yiaddr'   0                     0                     0
// 'siaddr'   0                     0                     0
// 'giaddr'   0                     0                     0
// 'chaddr'   client's hardware     client's hardware     client's hardware
//            address               address               address
// 'sname'    options, if           options, if           (unused)
//            indicated in          indicated in
//            'sname/file'          'sname/file'
//            option; otherwise     option; otherwise
//            unused                unused
// 'file'     options, if           options, if           (unused)
//            indicated in          indicated in
//            'sname/file'          'sname/file'
//            option; otherwise     option; otherwise
//            unused                unused
// 'options'  options               options               (unused)
//
// Option                     DHCPDISCOVER  DHCPREQUEST      DHCPDECLINE,
//                            DHCPINFORM                     DHCPRELEASE
// ------                     ------------  -----------      -----------
// Requested IP address       MAY           MUST (in         MUST
//                            (DISCOVER)    SELECTING or     (DHCPDECLINE),
//                            MUST NOT      INIT-REBOOT)     MUST NOT
//                            (INFORM)      MUST NOT (in     (DHCPRELEASE)
//                                          BOUND or
//                                          RENEWING)
// IP address lease time      MAY           MAY              MUST NOT
//                            (DISCOVER)
//                            MUST NOT
//                            (INFORM)
// Use 'file'/'sname' fields  MAY           MAY              MAY
// Client identifier          MAY           MAY              MAY
// Vendor class identifier    MAY           MAY              MUST NOT
// Server identifier          MUST NOT      MUST (after      MUST
//                                          SELECTING)
//                                          MUST NOT (after
//                                          INIT-REBOOT,
//                                          BOUND, RENEWING
//                                          or REBINDING)
// Parameter request list     MAY           MAY              MUST NOT
// Maximum message size       MAY           MAY              MUST NOT
// Message                    SHOULD NOT    SHOULD NOT       SHOULD
// Site-specific              MAY           MAY              MUST NOT
// All others                 MAY           MAY              MUST NOT


uint16_t udhcp_checksum(void *addr, int count) FAST_FUNC;

void udhcp_init_header(struct dhcp_packet *packet, char type) FAST_FUNC;

int udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd) FAST_FUNC;

int udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
		uint32_t source_ip, int source_port,
		uint32_t dest_ip, int dest_port, const uint8_t *dest_arp,
		int ifindex) FAST_FUNC;

int udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
		uint32_t source_ip, int source_port,
		uint32_t dest_ip, int dest_port) FAST_FUNC;


/**/

void udhcp_run_script(struct dhcp_packet *packet, const char *name) FAST_FUNC;

// Still need to clean these up...

/* from options.h */
#define get_option		udhcp_get_option
#define end_option		udhcp_end_option
#define add_option_string	udhcp_add_option_string
#define add_simple_option	udhcp_add_simple_option

void udhcp_sp_setup(void) FAST_FUNC;
int udhcp_sp_fd_set(fd_set *rfds, int extra_fd) FAST_FUNC;
int udhcp_sp_read(const fd_set *rfds) FAST_FUNC;
int udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac) FAST_FUNC;
int udhcp_listen_socket(/*uint32_t ip,*/ int port, const char *inf) FAST_FUNC;
/* Returns 1 if no reply received */
int arpping(uint32_t test_nip,
		const uint8_t *safe_mac,
		uint32_t from_ip,
		uint8_t *from_mac,
		const char *interface) FAST_FUNC;

#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
extern unsigned dhcp_verbose;
# define log1(...) do { if (dhcp_verbose >= 1) bb_info_msg(__VA_ARGS__); } while (0)
# if CONFIG_UDHCP_DEBUG >= 2
void udhcp_dump_packet(struct dhcp_packet *packet) FAST_FUNC;
#  define log2(...) do { if (dhcp_verbose >= 2) bb_info_msg(__VA_ARGS__); } while (0)
# else
#  define udhcp_dump_packet(...) ((void)0)
#  define log2(...) ((void)0)
# endif
# if CONFIG_UDHCP_DEBUG >= 3
#  define log3(...) do { if (dhcp_verbose >= 3) bb_info_msg(__VA_ARGS__); } while (0)
# else
#  define log3(...) ((void)0)
# endif
#else
# define udhcp_dump_packet(...) ((void)0)
# define log1(...) ((void)0)
# define log2(...) ((void)0)
# define log3(...) ((void)0)
#endif

POP_SAVED_FUNCTION_VISIBILITY

#endif