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busybox/networking/udhcp/common.h
Martin Lewis acdc8eed89 udhcp: add option scanner 
Added an option scanner to udhcp to enable iteration over packet options.

Signed-off-by: Martin Lewis <martin.lewis.x84@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2020-06-29 14:57:02 +02:00

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/* vi: set sw=4 ts=4: */
/*
* 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 source tree.
*/
#ifndef UDHCP_COMMON_H
#define UDHCP_COMMON_H 1
#include "libbb.h"
#include "common_bufsiz.h"
#include <netinet/udp.h>
#include <netinet/ip.h>
PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
extern const uint8_t MAC_BCAST_ADDR[6] ALIGN2; /* six all-ones */
/*** DHCP packet ***/
/* 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; /* aka 'giaddr': 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;
struct udp_dhcp_packet {
struct udphdr udp;
struct dhcp_packet data;
} PACKED;
enum {
IP_UDP_DHCP_SIZE = sizeof(struct ip_udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
UDP_DHCP_SIZE = sizeof(struct udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
DHCP_SIZE = sizeof(struct dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
};
/* Let's see whether compiler understood us right */
struct BUG_bad_sizeof_struct_ip_udp_dhcp_packet {
char c[IP_UDP_DHCP_SIZE == 576 ? 1 : -1];
};
/*** Options ***/
enum {
OPTION_IP = 0,
OPTION_IP_PAIR,
OPTION_STRING,
/* Opts of STRING_HOST type will be sanitized before they are passed
* to udhcpc script's environment: */
OPTION_STRING_HOST,
// OPTION_BOOLEAN,
OPTION_U8,
OPTION_U16,
// OPTION_S16,
OPTION_U32,
OPTION_S32,
OPTION_BIN,
OPTION_STATIC_ROUTES,
OPTION_6RD,
#if ENABLE_FEATURE_UDHCP_RFC3397 || ENABLE_FEATURE_UDHCPC6_RFC3646 || ENABLE_FEATURE_UDHCPC6_RFC4704
OPTION_DNS_STRING, /* RFC1035 compressed domain name list */
#endif
#if ENABLE_FEATURE_UDHCP_RFC3397
OPTION_SIP_SERVERS,
#endif
OPTION_TYPE_MASK = 0x0f,
/* Client requests this option by default */
OPTION_REQ = 0x10,
/* There can be a list of 1 or more of these */
OPTION_LIST = 0x20,
};
struct dhcp_scan_state {
int overload;
int rem;
uint8_t *optionptr;
};
/* DHCP option codes (partial list). See RFC 2132 and
* http://www.iana.org/assignments/bootp-dhcp-parameters/
* Commented out options are handled by common option machinery,
* uncommented ones have special cases (grep for them to see).
*/
#define DHCP_PADDING 0x00
#define DHCP_SUBNET 0x01
//#define DHCP_TIME_OFFSET 0x02 /* (localtime - UTC_time) in seconds. signed */
//#define DHCP_ROUTER 0x03
//#define DHCP_TIME_SERVER 0x04 /* RFC 868 time server (32-bit, 0 = 1.1.1900) */
//#define DHCP_NAME_SERVER 0x05 /* IEN 116 _really_ ancient kind of NS */
//#define DHCP_DNS_SERVER 0x06
//#define DHCP_LOG_SERVER 0x07 /* port 704 UDP log (not syslog) */
//#define DHCP_COOKIE_SERVER 0x08 /* "quote of the day" server */
//#define DHCP_LPR_SERVER 0x09
#define DHCP_HOST_NAME 0x0c /* 12: either client informs server or server gives name to client */
//#define DHCP_BOOT_SIZE 0x0d
//#define DHCP_DOMAIN_NAME 0x0f /* 15: server gives domain suffix */
//#define DHCP_SWAP_SERVER 0x10
//#define DHCP_ROOT_PATH 0x11
//#define DHCP_IP_TTL 0x17
//#define DHCP_MTU 0x1a
//#define DHCP_BROADCAST 0x1c
//#define DHCP_ROUTES 0x21
//#define DHCP_NIS_DOMAIN 0x28
//#define DHCP_NIS_SERVER 0x29
//#define DHCP_NTP_SERVER 0x2a
//#define DHCP_WINS_SERVER 0x2c
#define DHCP_REQUESTED_IP 0x32 /* 50: sent by client if specific IP is wanted */
#define DHCP_LEASE_TIME 0x33 /* 51: */
#define DHCP_OPTION_OVERLOAD 0x34 /* 52: */
#define DHCP_MESSAGE_TYPE 0x35 /* 53: */
#define DHCP_SERVER_ID 0x36 /* 54: server's IP */
#define DHCP_PARAM_REQ 0x37 /* 55: list of options client wants */
//#define DHCP_ERR_MESSAGE 0x38 /* 56: error message when sending NAK etc */
#define DHCP_MAX_SIZE 0x39 /* 57: */
#define DHCP_VENDOR 0x3c /* 60: client's vendor (a string) */
#define DHCP_CLIENT_ID 0x3d /* 61: by default client's MAC addr, but may be arbitrarily long */
//#define DHCP_TFTP_SERVER_NAME 0x42 /* 66: same as 'sname' field */
//#define DHCP_BOOT_FILE 0x43 /* 67: same as 'file' field */
//#define DHCP_USER_CLASS 0x4d /* 77: RFC 3004. set of LASCII strings. "I am a printer" etc */
#define DHCP_FQDN 0x51 /* 81: client asks to update DNS to map its FQDN to its new IP */
//#define DHCP_PCODE 0x64 /* 100: RFC 4833. IEEE 1003.1 TZ string */
//#define DHCP_TCODE 0x65 /* 101: RFC 4833. Reference to the TZ database string */
//#define DHCP_DOMAIN_SEARCH 0x77 /* 119: RFC 3397. set of ASCIZ string, DNS-style compressed */
//#define DHCP_SIP_SERVERS 0x78 /* 120: RFC 3361. flag byte, then: 0: domain names, 1: IP addrs */
//#define DHCP_STATIC_ROUTES 0x79 /* 121: RFC 3442. (mask,ip,router) tuples */
//#define DHCP_VLAN_ID 0x84 /* 132: 802.1P VLAN ID */
//#define DHCP_VLAN_PRIORITY 0x85 /* 133: 802.1Q VLAN priority */
//#define DHCP_PXE_CONF_FILE 0xd1 /* 209: RFC 5071 Configuration file */
//#define DHCP_PXE_PATH_PREFIX 0xd2 /* 210: RFC 5071 Path prefix */
//#define DHCP_REBOOT_TIME 0xd3 /* 211: RFC 5071 Reboot time */
//#define DHCP_MS_STATIC_ROUTES 0xf9 /* 249: Microsoft's pre-RFC 3442 code for 0x79? */
//#define DHCP_WPAD 0xfc /* 252: MSIE's Web Proxy Autodiscovery Protocol */
#define DHCP_END 0xff /* 255: */
/* Offsets in option byte sequence */
#define OPT_CODE 0
#define OPT_LEN 1
#define OPT_DATA 2
/* Offsets in option byte sequence for DHCPv6 */
#define D6_OPT_CODE 0
#define D6_OPT_LEN 2
#define D6_OPT_DATA 4
/* Bits in "overload" option */
#define OPTION_FIELD 0
#define FILE_FIELD 1
#define SNAME_FIELD 2
/* DHCP_MESSAGE_TYPE values */
#define DHCPDISCOVER 1 /* client -> server */
#define DHCPOFFER 2 /* client <- server */
#define DHCPREQUEST 3 /* client -> server */
#define DHCPDECLINE 4 /* client -> server */
#define DHCPACK 5 /* client <- server */
#define DHCPNAK 6 /* client <- server */
#define DHCPRELEASE 7 /* client -> server */
#define DHCPINFORM 8 /* client -> server */
#define DHCP_MINTYPE DHCPDISCOVER
#define DHCP_MAXTYPE DHCPINFORM
struct dhcp_optflag {
uint8_t flags;
uint8_t code;
};
struct option_set {
uint8_t *data;
struct option_set *next;
};
#if ENABLE_UDHCPC || ENABLE_UDHCPD
extern const struct dhcp_optflag dhcp_optflags[];
extern const char dhcp_option_strings[] ALIGN1;
#endif
extern const uint8_t dhcp_option_lengths[] ALIGN1;
unsigned FAST_FUNC udhcp_option_idx(const char *name, const char *option_strings);
void init_scan_state(struct dhcp_packet *packet, struct dhcp_scan_state *scan_state) FAST_FUNC;
uint8_t *udhcp_scan_options(struct dhcp_packet *packet, struct dhcp_scan_state *scan_state) FAST_FUNC;
uint8_t *udhcp_get_option(struct dhcp_packet *packet, int code) FAST_FUNC;
/* Same as above + ensures that option length is 4 bytes
* (returns NULL if size is different)
*/
uint8_t *udhcp_get_option32(struct dhcp_packet *packet, int code) FAST_FUNC;
int udhcp_end_option(uint8_t *optionptr) FAST_FUNC;
void udhcp_add_binary_option(struct dhcp_packet *packet, uint8_t *addopt) FAST_FUNC;
#if ENABLE_UDHCPC || ENABLE_UDHCPD
void udhcp_add_simple_option(struct dhcp_packet *packet, uint8_t code, uint32_t data) FAST_FUNC;
#endif
#if ENABLE_FEATURE_UDHCP_RFC3397 || ENABLE_FEATURE_UDHCPC6_RFC3646 || ENABLE_FEATURE_UDHCPC6_RFC4704
char *dname_dec(const uint8_t *cstr, int clen, const char *pre) FAST_FUNC;
uint8_t *dname_enc(/*const uint8_t *cstr, int clen,*/ const char *src, int *retlen) FAST_FUNC;
#endif
struct option_set *udhcp_find_option(struct option_set *opt_list, uint8_t code) FAST_FUNC;
// RFC 2131 Table 5: Fields and options used by DHCP clients
//
// Fields 'hops', 'yiaddr', 'siaddr', 'giaddr' are always zero, 'chaddr' is always client's MAC
//
// Field DHCPDISCOVER DHCPINFORM DHCPREQUEST DHCPDECLINE DHCPRELEASE
// ----- ------------ ------------ ----------- ----------- -----------
// 'xid' selected by client selected by client 'xid' from server selected by client selected by client
// DHCPOFFER message
// 'secs' 0 or seconds since 0 or seconds since 0 or seconds since 0 0
// DHCP process started DHCP process started DHCP process started
// 'flags' Set 'BROADCAST' Set 'BROADCAST' Set 'BROADCAST' 0 0
// flag if client needs flag if client needs flag if client needs
// broadcast reply broadcast reply broadcast reply
// 'ciaddr' 0 client's IP 0 or client's IP 0 client's IP
// (BOUND/RENEW/REBIND)
// 'sname' options or sname options or sname options or sname (unused) (unused)
// 'file' options or file options or file options or file (unused) (unused)
// 'options' options options options message type opt message type opt
//
// Option DHCPDISCOVER DHCPINFORM DHCPREQUEST DHCPDECLINE DHCPRELEASE
// ------ ------------ ---------- ----------- ----------- -----------
// Requested IP address MAY MUST NOT MUST (in SELECTING MUST MUST NOT
// or INIT-REBOOT)
// MUST NOT (in BOUND
// or RENEWING)
// IP address lease time MAY MUST NOT MAY MUST NOT MUST NOT
// Use 'file'/'sname' fields MAY MAY MAY MAY MAY
// Client identifier MAY MAY MAY MAY MAY
// Vendor class identifier MAY MAY MAY MUST NOT MUST NOT
// Server identifier MUST NOT MUST NOT MUST (after SELECTING) MUST MUST
// MUST NOT (after
// INIT-REBOOT, BOUND,
// RENEWING or REBINDING)
// Parameter request list MAY MAY MAY MUST NOT MUST NOT
// Maximum message size MAY MAY MAY MUST NOT MUST NOT
// Message SHOULD NOT SHOULD NOT SHOULD NOT SHOULD SHOULD
// Site-specific MAY MAY MAY MUST NOT MUST NOT
// All others MAY MAY MAY MUST NOT MUST NOT
/*** Logging ***/
#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
extern unsigned dhcp_verbose;
# define log1(...) do { if (dhcp_verbose >= 1) bb_info_msg(__VA_ARGS__); } while (0)
# define log1s(msg) do { if (dhcp_verbose >= 1) bb_simple_info_msg(msg); } 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)
# define log2s(msg) do { if (dhcp_verbose >= 2) bb_simple_info_msg(msg); } while (0)
# else
# define udhcp_dump_packet(...) ((void)0)
# define log2(...) ((void)0)
# define log2s(msg) ((void)0)
# endif
# if CONFIG_UDHCP_DEBUG >= 3
# define log3(...) do { if (dhcp_verbose >= 3) bb_info_msg(__VA_ARGS__); } while (0)
# define log3s(msg) do { if (dhcp_verbose >= 3) bb_simple_info_msg(msg); } while (0)
# else
# define log3(...) ((void)0)
# define log3s(msg) ((void)0)
# endif
#else
# define IF_UDHCP_VERBOSE(...)
# define udhcp_dump_packet(...) ((void)0)
# define log1(...) ((void)0)
# define log1s(msg) ((void)0)
# define log2(...) ((void)0)
# define log2s(msg) ((void)0)
# define log3(...) ((void)0)
# define log3s(msg) ((void)0)
#endif
#if defined(__mips__)
/*
* The 'simple' message functions have a negative impact on the size of the
* DHCP code when compiled for MIPS, so don't use them in this case.
*/
#define bb_simple_info_msg bb_info_msg
#define bb_simple_error_msg bb_error_msg
#define bb_simple_perror_msg_and_die bb_perror_msg_and_die
#undef log1s
#define log1s log1
#endif
/*** Other shared functions ***/
/* 2nd param is "uint32_t*" */
int FAST_FUNC udhcp_str2nip(const char *str, void *arg);
/* 2nd param is "struct option_set**" */
#if !ENABLE_UDHCPC6
#define udhcp_str2optset(str, arg, optflags, option_strings, dhcpv6) \
udhcp_str2optset(str, arg, optflags, option_strings)
#endif
int FAST_FUNC udhcp_str2optset(const char *str,
void *arg,
const struct dhcp_optflag *optflags,
const char *option_strings,
bool dhcpv6);
#if ENABLE_UDHCPC || ENABLE_UDHCPD
void udhcp_init_header(struct dhcp_packet *packet, char type) FAST_FUNC;
#endif
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_nip, int source_port,
uint32_t dest_nip, 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_nip, int source_port,
uint32_t dest_nip, int dest_port) FAST_FUNC;
void udhcp_sp_setup(void) FAST_FUNC;
void udhcp_sp_fd_set(struct pollfd *pfds, int extra_fd) FAST_FUNC;
int udhcp_sp_read(void) 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,
unsigned timeo) FAST_FUNC;
/* note: ip is a pointer to an IPv6 in network order, possibly misaliged */
int sprint_nip6(char *dest, /*const char *pre,*/ const uint8_t *ip) FAST_FUNC;
POP_SAVED_FUNCTION_VISIBILITY
#endif
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