release/src/router/busybox/networking/udhcp/common.h

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Russ Dill <Russ.Dill@asu.edu> September 2001
   4  * Rewritten by Vladimir Oleynik <dzo@simtreas.ru> (C) 2003
   5  *
   6  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   7  */
   8 #ifndef UDHCP_COMMON_H
   9 #define UDHCP_COMMON_H 1
  10
  11 #include "libbb.h"
  12 #include <netinet/udp.h>
  13 #include <netinet/ip.h>
  14
  15 PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
  16
  17 extern const uint8_t MAC_BCAST_ADDR[6]; /* six all-ones */
  18
  19
  20 /*** DHCP packet ***/
  21
  22 /* DHCP protocol. See RFC 2131 */
  23 #define DHCP_MAGIC              0x63825363
  24 #define DHCP_OPTIONS_BUFSIZE    308
  25 #define BOOTREQUEST             1
  26 #define BOOTREPLY               2
  27
  28 //TODO: rename ciaddr/yiaddr/chaddr
  29 struct dhcp_packet {
  30         uint8_t op;      /* BOOTREQUEST or BOOTREPLY */
  31         uint8_t htype;   /* hardware address type. 1 = 10mb ethernet */
  32         uint8_t hlen;    /* hardware address length */
  33         uint8_t hops;    /* used by relay agents only */
  34         uint32_t xid;    /* unique id */
  35         uint16_t secs;   /* elapsed since client began acquisition/renewal */
  36         uint16_t flags;  /* only one flag so far: */
  37 #define BROADCAST_FLAG 0x8000 /* "I need broadcast replies" */
  38         uint32_t ciaddr; /* client IP (if client is in BOUND, RENEW or REBINDING state) */
  39         uint32_t yiaddr; /* 'your' (client) IP address */
  40         /* IP address of next server to use in bootstrap, returned in DHCPOFFER, DHCPACK by server */
  41         uint32_t siaddr_nip;
  42         uint32_t gateway_nip; /* relay agent IP address */
  43         uint8_t chaddr[16];   /* link-layer client hardware address (MAC) */
  44         uint8_t sname[64];    /* server host name (ASCIZ) */
  45         uint8_t file[128];    /* boot file name (ASCIZ) */
  46         uint32_t cookie;      /* fixed first four option bytes (99,130,83,99 dec) */
  47         uint8_t options[DHCP_OPTIONS_BUFSIZE + CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS];
  48 } PACKED;
  49 #define DHCP_PKT_SNAME_LEN      64
  50 #define DHCP_PKT_FILE_LEN      128
  51 #define DHCP_PKT_SNAME_LEN_STR "64"
  52 #define DHCP_PKT_FILE_LEN_STR "128"
  53
  54 struct ip_udp_dhcp_packet {
  55         struct iphdr ip;
  56         struct udphdr udp;
  57         struct dhcp_packet data;
  58 } PACKED;
  59
  60 struct udp_dhcp_packet {
  61         struct udphdr udp;
  62         struct dhcp_packet data;
  63 } PACKED;
  64
  65 enum {
  66         IP_UDP_DHCP_SIZE = sizeof(struct ip_udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
  67         UDP_DHCP_SIZE    = sizeof(struct udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
  68         DHCP_SIZE        = sizeof(struct dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
  69 };
  70
  71 /* Let's see whether compiler understood us right */
  72 struct BUG_bad_sizeof_struct_ip_udp_dhcp_packet {
  73         char c[IP_UDP_DHCP_SIZE == 576 ? 1 : -1];
  74 };
  75
  76 extern int minpkt;      // zzz
  77
  78
  79 /*** Options ***/
  80
  81 enum {
  82         OPTION_IP = 1,
  83         OPTION_IP_PAIR,
  84         OPTION_STRING,
  85 //      OPTION_BOOLEAN,
  86         OPTION_U8,
  87         OPTION_U16,
  88 //      OPTION_S16,
  89         OPTION_U32,
  90         OPTION_S32,
  91         OPTION_BIN,
  92         OPTION_STATIC_ROUTES,
  93 #if ENABLE_FEATURE_UDHCP_RFC3397
  94         OPTION_DNS_STRING,  /* RFC1035 compressed domain name list */
  95         OPTION_SIP_SERVERS,
  96 #endif
  97 #if ENABLE_FEATURE_UDHCP_RFC5969
  98         OPTION_6RD,
  99 #endif
 100
 101         OPTION_TYPE_MASK = 0x0f,
 102         /* Client requests this option by default */
 103         OPTION_REQ  = 0x10,
 104         /* There can be a list of 1 or more of these */
 105         OPTION_LIST = 0x20,
 106 };
 107
 108 /* DHCP option codes (partial list). See RFC 2132 and
 109  * http://www.iana.org/assignments/bootp-dhcp-parameters/
 110  * Commented out options are handled by common option machinery,
 111  * uncommented ones have spacial cases (grep for them to see).
 112  */
 113 #define DHCP_PADDING            0x00
 114 #define DHCP_SUBNET             0x01
 115 //#define DHCP_TIME_OFFSET      0x02 /* (localtime - UTC_time) in seconds. signed */
 116 //#define DHCP_ROUTER           0x03
 117 //#define DHCP_TIME_SERVER      0x04 /* RFC 868 time server (32-bit, 0 = 1.1.1900) */
 118 //#define DHCP_NAME_SERVER      0x05 /* IEN 116 _really_ ancient kind of NS */
 119 //#define DHCP_DNS_SERVER       0x06
 120 //#define DHCP_LOG_SERVER       0x07 /* port 704 UDP log (not syslog)
 121 //#define DHCP_COOKIE_SERVER    0x08 /* "quote of the day" server */
 122 //#define DHCP_LPR_SERVER       0x09
 123 #define DHCP_HOST_NAME          0x0c /* either client informs server or server gives name to client */
 124 //#define DHCP_BOOT_SIZE        0x0d
 125 //#define DHCP_DOMAIN_NAME      0x0f /* server gives domain suffix */
 126 //#define DHCP_SWAP_SERVER      0x10
 127 //#define DHCP_ROOT_PATH        0x11
 128 //#define DHCP_IP_TTL           0x17
 129 //#define DHCP_MTU              0x1a
 130 //#define DHCP_BROADCAST        0x1c
 131 //#define DHCP_ROUTES           0x21
 132 //#define DHCP_NIS_DOMAIN       0x28
 133 //#define DHCP_NIS_SERVER       0x29
 134 //#define DHCP_NTP_SERVER       0x2a
 135 //#define DHCP_WINS_SERVER      0x2c
 136 #define DHCP_REQUESTED_IP       0x32 /* sent by client if specific IP is wanted */
 137 #define DHCP_LEASE_TIME         0x33
 138 #define DHCP_OPTION_OVERLOAD    0x34
 139 #define DHCP_MESSAGE_TYPE       0x35
 140 #define DHCP_SERVER_ID          0x36 /* by default server's IP */
 141 #define DHCP_PARAM_REQ          0x37 /* list of options client wants */
 142 //#define DHCP_ERR_MESSAGE      0x38 /* error message when sending NAK etc */
 143 #define DHCP_MAX_SIZE           0x39
 144 #define DHCP_VENDOR             0x3c /* client's vendor (a string) */
 145 #define DHCP_CLIENT_ID          0x3d /* by default client's MAC addr, but may be arbitrarily long */
 146 //#define DHCP_TFTP_SERVER_NAME 0x42 /* same as 'sname' field */
 147 //#define DHCP_BOOT_FILE        0x43 /* same as 'file' field */
 148 //#define DHCP_USER_CLASS       0x4d /* RFC 3004. set of LASCII strings. "I am a printer" etc */
 149 #define DHCP_FQDN               0x51 /* client asks to update DNS to map its FQDN to its new IP */
 150 //#define DHCP_DOMAIN_SEARCH    0x77 /* RFC 3397. set of ASCIZ string, DNS-style compressed */
 151 //#define DHCP_SIP_SERVERS      0x78 /* RFC 3361. flag byte, then: 0: domain names, 1: IP addrs */
 152 //#define DHCP_STATIC_ROUTES    0x79 /* RFC 3442. (mask,ip,router) tuples */
 153 //#define DHCP_MS_STATIC_ROUTES 0xf9 /* Microsoft's pre-RFC 3442 code for 0x79? */
 154 //#define DHCP_6RD              0xd4 /* RFC 5969 6RD option */
 155 //#define DHCP_COMCAST_6RD      0x96 /* Comcast ISP RFC 5969 compatible 6RD option */
 156 //#define DHCP_WPAD             0xfc /* MSIE's Web Proxy Autodiscovery Protocol */
 157 #define DHCP_END                0xff
 158
 159 /* Offsets in option byte sequence */
 160 #define OPT_CODE                0
 161 #define OPT_LEN                 1
 162 #define OPT_DATA                2
 163 /* Bits in "overload" option */
 164 #define OPTION_FIELD            0
 165 #define FILE_FIELD              1
 166 #define SNAME_FIELD             2
 167
 168 /* DHCP_MESSAGE_TYPE values */
 169 #define DHCPDISCOVER            1 /* client -> server */
 170 #define DHCPOFFER               2 /* client <- server */
 171 #define DHCPREQUEST             3 /* client -> server */
 172 #define DHCPDECLINE             4 /* client -> server */
 173 #define DHCPACK                 5 /* client <- server */
 174 #define DHCPNAK                 6 /* client <- server */
 175 #define DHCPRELEASE             7 /* client -> server */
 176 #define DHCPINFORM              8 /* client -> server */
 177 #define DHCP_MINTYPE DHCPDISCOVER
 178 #define DHCP_MAXTYPE DHCPINFORM
 179
 180 struct dhcp_optflag {
 181         uint8_t flags;
 182         uint8_t code;
 183 };
 184
 185 struct option_set {
 186         uint8_t *data;
 187         struct option_set *next;
 188 };
 189
 190 extern const struct dhcp_optflag dhcp_optflags[];
 191 extern const char dhcp_option_strings[];
 192 extern const uint8_t dhcp_option_lengths[];
 193
 194 unsigned FAST_FUNC udhcp_option_idx(const char *name);
 195
 196 uint8_t *udhcp_get_option(struct dhcp_packet *packet, int code) FAST_FUNC;
 197 int udhcp_end_option(uint8_t *optionptr) FAST_FUNC;
 198 void udhcp_add_binary_option(struct dhcp_packet *packet, uint8_t *addopt) FAST_FUNC;
 199 void udhcp_add_simple_option(struct dhcp_packet *packet, uint8_t code, uint32_t data) FAST_FUNC;
 200 #if ENABLE_FEATURE_UDHCP_RFC3397
 201 char *dname_dec(const uint8_t *cstr, int clen, const char *pre) FAST_FUNC;
 202 uint8_t *dname_enc(const uint8_t *cstr, int clen, const char *src, int *retlen) FAST_FUNC;
 203 #endif
 204 struct option_set *udhcp_find_option(struct option_set *opt_list, uint8_t code) FAST_FUNC;
 205
 206
 207 // RFC 2131  Table 5: Fields and options used by DHCP clients
 208 //
 209 // Fields 'hops', 'yiaddr', 'siaddr', 'giaddr' are always zero
 210 //
 211 // Field      DHCPDISCOVER          DHCPINFORM            DHCPREQUEST           DHCPDECLINE         DHCPRELEASE
 212 // -----      ------------          ------------          -----------           -----------         -----------
 213 // 'xid'      selected by client    selected by client    'xid' from server     selected by client  selected by client
 214 //                                                        DHCPOFFER message
 215 // 'secs'     0 or seconds since    0 or seconds since    0 or seconds since    0                   0
 216 //            DHCP process started  DHCP process started  DHCP process started
 217 // 'flags'    Set 'BROADCAST'       Set 'BROADCAST'       Set 'BROADCAST'       0                   0
 218 //            flag if client        flag if client        flag if client
 219 //            requires broadcast    requires broadcast    requires broadcast
 220 //            reply                 reply                 reply
 221 // 'ciaddr'   0                     client's IP           0 or client's IP      0                   client's IP
 222 //                                                        (BOUND/RENEW/REBIND)
 223 // 'chaddr'   client's MAC          client's MAC          client's MAC          client's MAC        client's MAC
 224 // 'sname'    options or sname      options or sname      options or sname      (unused)            (unused)
 225 // 'file'     options or file       options or file       options or file       (unused)            (unused)
 226 // 'options'  options               options               options               message type opt    message type opt
 227 //
 228 // Option                     DHCPDISCOVER  DHCPINFORM  DHCPREQUEST      DHCPDECLINE  DHCPRELEASE
 229 // ------                     ------------  ----------  -----------      -----------  -----------
 230 // Requested IP address       MAY           MUST NOT    MUST (in         MUST         MUST NOT
 231 //                                                      SELECTING or
 232 //                                                      INIT-REBOOT)
 233 //                                                      MUST NOT (in
 234 //                                                      BOUND or
 235 //                                                      RENEWING)
 236 // IP address lease time      MAY           MUST NOT    MAY              MUST NOT     MUST NOT
 237 // Use 'file'/'sname' fields  MAY           MAY         MAY              MAY          MAY
 238 // Client identifier          MAY           MAY         MAY              MAY          MAY
 239 // Vendor class identifier    MAY           MAY         MAY              MUST NOT     MUST NOT
 240 // Server identifier          MUST NOT      MUST NOT    MUST (after      MUST         MUST
 241 //                                                      SELECTING)
 242 //                                                      MUST NOT (after
 243 //                                                      INIT-REBOOT,
 244 //                                                      BOUND, RENEWING
 245 //                                                      or REBINDING)
 246 // Parameter request list     MAY           MAY         MAY              MUST NOT     MUST NOT
 247 // Maximum message size       MAY           MAY         MAY              MUST NOT     MUST NOT
 248 // Message                    SHOULD NOT    SHOULD NOT  SHOULD NOT       SHOULD       SHOULD
 249 // Site-specific              MAY           MAY         MAY              MUST NOT     MUST NOT
 250 // All others                 MAY           MAY         MAY              MUST NOT     MUST NOT
 251
 252
 253 /*** Logging ***/
 254
 255 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
 256 extern unsigned dhcp_verbose;
 257 # define log1(...) do { if (dhcp_verbose >= 1) bb_info_msg(__VA_ARGS__); } while (0)
 258 # if CONFIG_UDHCP_DEBUG >= 2
 259 void udhcp_dump_packet(struct dhcp_packet *packet) FAST_FUNC;
 260 #  define log2(...) do { if (dhcp_verbose >= 2) bb_info_msg(__VA_ARGS__); } while (0)
 261 # else
 262 #  define udhcp_dump_packet(...) ((void)0)
 263 #  define log2(...) ((void)0)
 264 # endif
 265 # if CONFIG_UDHCP_DEBUG >= 3
 266 #  define log3(...) do { if (dhcp_verbose >= 3) bb_info_msg(__VA_ARGS__); } while (0)
 267 # else
 268 #  define log3(...) ((void)0)
 269 # endif
 270 #else
 271 # define udhcp_dump_packet(...) ((void)0)
 272 # define log1(...) ((void)0)
 273 # define log2(...) ((void)0)
 274 # define log3(...) ((void)0)
 275 #endif
 276
 277
 278 /*** Other shared functions ***/
 279
 280 /* 2nd param is "uint32_t*" */
 281 int FAST_FUNC udhcp_str2nip(const char *str, void *arg);
 282 /* 2nd param is "struct option_set**" */
 283 int FAST_FUNC udhcp_str2optset(const char *str, void *arg);
 284
 285 uint16_t udhcp_checksum(void *addr, int count) FAST_FUNC;
 286
 287 void udhcp_init_header(struct dhcp_packet *packet, char type) FAST_FUNC;
 288
 289 int udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd) FAST_FUNC;
 290
 291 int udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
 292                 uint32_t source_nip, int source_port,
 293                 uint32_t dest_nip, int dest_port, const uint8_t *dest_arp,
 294                 int ifindex) FAST_FUNC;
 295
 296 int udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
 297                 uint32_t source_nip, int source_port,
 298                 uint32_t dest_nip, int dest_port) FAST_FUNC;
 299
 300 void udhcp_sp_setup(void) FAST_FUNC;
 301 int udhcp_sp_fd_set(fd_set *rfds, int extra_fd) FAST_FUNC;
 302 int udhcp_sp_read(const fd_set *rfds) FAST_FUNC;
 303
 304 int udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac, uint16_t *mtu) FAST_FUNC;
 305
 306 int udhcp_listen_socket(/*uint32_t ip,*/ int port, const char *inf) FAST_FUNC;
 307
 308 /* Returns 1 if no reply received */
 309 int arpping(uint32_t test_nip,
 310                 const uint8_t *safe_mac,
 311                 uint32_t from_ip,
 312                 uint8_t *from_mac,
 313                 const char *interface) FAST_FUNC;
 314
 315 POP_SAVED_FUNCTION_VISIBILITY
 316
 317 #endif