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] ALIGN2; /* 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         /* Opts of STRING_HOST type will be sanitized before they are passed
  86          * to udhcpc script's environment: */
  87         OPTION_STRING_HOST,
  88 //      OPTION_BOOLEAN,
  89         OPTION_U8,
  90         OPTION_U16,
  91 //      OPTION_S16,
  92         OPTION_U32,
  93         OPTION_S32,
  94         OPTION_BIN,
  95         OPTION_STATIC_ROUTES,
  96         OPTION_6RD,
  97 #if ENABLE_FEATURE_UDHCP_RFC3397
  98         OPTION_DNS_STRING,  /* RFC1035 compressed domain name list */
  99         OPTION_SIP_SERVERS,
 100 #endif
 101
 102         OPTION_TYPE_MASK = 0x0f,
 103         /* Client requests this option by default */
 104         OPTION_REQ  = 0x10,
 105         /* There can be a list of 1 or more of these */
 106         OPTION_LIST = 0x20,
 107 };
 108
 109 /* DHCP option codes (partial list). See RFC 2132 and
 110  * http://www.iana.org/assignments/bootp-dhcp-parameters/
 111  * Commented out options are handled by common option machinery,
 112  * uncommented ones have special cases (grep for them to see).
 113  */
 114 #define DHCP_PADDING            0x00
 115 #define DHCP_SUBNET             0x01
 116 //#define DHCP_TIME_OFFSET      0x02 /* (localtime - UTC_time) in seconds. signed */
 117 //#define DHCP_ROUTER           0x03
 118 //#define DHCP_TIME_SERVER      0x04 /* RFC 868 time server (32-bit, 0 = 1.1.1900) */
 119 //#define DHCP_NAME_SERVER      0x05 /* IEN 116 _really_ ancient kind of NS */
 120 //#define DHCP_DNS_SERVER       0x06
 121 //#define DHCP_LOG_SERVER       0x07 /* port 704 UDP log (not syslog)
 122 //#define DHCP_COOKIE_SERVER    0x08 /* "quote of the day" server */
 123 //#define DHCP_LPR_SERVER       0x09
 124 #define DHCP_HOST_NAME          0x0c /* either client informs server or server gives name to client */
 125 //#define DHCP_BOOT_SIZE        0x0d
 126 //#define DHCP_DOMAIN_NAME      0x0f /* server gives domain suffix */
 127 //#define DHCP_SWAP_SERVER      0x10
 128 //#define DHCP_ROOT_PATH        0x11
 129 //#define DHCP_IP_TTL           0x17
 130 //#define DHCP_MTU              0x1a
 131 //#define DHCP_BROADCAST        0x1c
 132 //#define DHCP_ROUTES           0x21
 133 //#define DHCP_NIS_DOMAIN       0x28
 134 //#define DHCP_NIS_SERVER       0x29
 135 //#define DHCP_NTP_SERVER       0x2a
 136 //#define DHCP_WINS_SERVER      0x2c
 137 #define DHCP_REQUESTED_IP       0x32 /* sent by client if specific IP is wanted */
 138 #define DHCP_LEASE_TIME         0x33
 139 #define DHCP_OPTION_OVERLOAD    0x34
 140 #define DHCP_MESSAGE_TYPE       0x35
 141 #define DHCP_SERVER_ID          0x36 /* by default server's IP */
 142 #define DHCP_PARAM_REQ          0x37 /* list of options client wants */
 143 //#define DHCP_ERR_MESSAGE      0x38 /* error message when sending NAK etc */
 144 #define DHCP_MAX_SIZE           0x39
 145 #define DHCP_VENDOR             0x3c /* client's vendor (a string) */
 146 #define DHCP_CLIENT_ID          0x3d /* by default client's MAC addr, but may be arbitrarily long */
 147 //#define DHCP_TFTP_SERVER_NAME 0x42 /* same as 'sname' field */
 148 //#define DHCP_BOOT_FILE        0x43 /* same as 'file' field */
 149 //#define DHCP_USER_CLASS       0x4d /* RFC 3004. set of LASCII strings. "I am a printer" etc */
 150 #define DHCP_FQDN               0x51 /* client asks to update DNS to map its FQDN to its new IP */
 151 //#define DHCP_DOMAIN_SEARCH    0x77 /* RFC 3397. set of ASCIZ string, DNS-style compressed */
 152 //#define DHCP_SIP_SERVERS      0x78 /* RFC 3361. flag byte, then: 0: domain names, 1: IP addrs */
 153 //#define DHCP_STATIC_ROUTES    0x79 /* RFC 3442. (mask,ip,router) tuples */
 154 #define DHCP_VLAN_ID            0x84 /* 802.1P VLAN ID */
 155 #define DHCP_VLAN_PRIORITY      0x85 /* 802.1Q VLAN priority */
 156 //#define DHCP_MS_STATIC_ROUTES 0xf9 /* Microsoft's pre-RFC 3442 code for 0x79? */
 157 //#define DHCP_WPAD             0xfc /* MSIE's Web Proxy Autodiscovery Protocol */
 158 #define DHCP_END                0xff
 159
 160 /* Offsets in option byte sequence */
 161 #define OPT_CODE                0
 162 #define OPT_LEN                 1
 163 #define OPT_DATA                2
 164 /* Bits in "overload" option */
 165 #define OPTION_FIELD            0
 166 #define FILE_FIELD              1
 167 #define SNAME_FIELD             2
 168
 169 /* DHCP_MESSAGE_TYPE values */
 170 #define DHCPDISCOVER            1 /* client -> server */
 171 #define DHCPOFFER               2 /* client <- server */
 172 #define DHCPREQUEST             3 /* client -> server */
 173 #define DHCPDECLINE             4 /* client -> server */
 174 #define DHCPACK                 5 /* client <- server */
 175 #define DHCPNAK                 6 /* client <- server */
 176 #define DHCPRELEASE             7 /* client -> server */
 177 #define DHCPINFORM              8 /* client -> server */
 178 #define DHCP_MINTYPE DHCPDISCOVER
 179 #define DHCP_MAXTYPE DHCPINFORM
 180
 181 struct dhcp_optflag {
 182         uint8_t flags;
 183         uint8_t code;
 184 };
 185
 186 struct option_set {
 187         uint8_t *data;
 188         struct option_set *next;
 189 };
 190
 191 extern const struct dhcp_optflag dhcp_optflags[];
 192 extern const char dhcp_option_strings[] ALIGN1;
 193 extern const uint8_t dhcp_option_lengths[] ALIGN1;
 194
 195 unsigned FAST_FUNC udhcp_option_idx(const char *name);
 196
 197 uint8_t *udhcp_get_option(struct dhcp_packet *packet, int code) FAST_FUNC;
 198 int udhcp_end_option(uint8_t *optionptr) FAST_FUNC;
 199 void udhcp_add_binary_option(struct dhcp_packet *packet, uint8_t *addopt) FAST_FUNC;
 200 void udhcp_add_simple_option(struct dhcp_packet *packet, uint8_t code, uint32_t data) FAST_FUNC;
 201 #if ENABLE_FEATURE_UDHCP_RFC3397
 202 char *dname_dec(const uint8_t *cstr, int clen, const char *pre) FAST_FUNC;
 203 uint8_t *dname_enc(const uint8_t *cstr, int clen, const char *src, int *retlen) FAST_FUNC;
 204 #endif
 205 struct option_set *udhcp_find_option(struct option_set *opt_list, uint8_t code) FAST_FUNC;
 206
 207
 208 // RFC 2131  Table 5: Fields and options used by DHCP clients
 209 //
 210 // Fields 'hops', 'yiaddr', 'siaddr', 'giaddr' are always zero
 211 //
 212 // Field      DHCPDISCOVER          DHCPINFORM            DHCPREQUEST           DHCPDECLINE         DHCPRELEASE
 213 // -----      ------------          ------------          -----------           -----------         -----------
 214 // 'xid'      selected by client    selected by client    'xid' from server     selected by client  selected by client
 215 //                                                        DHCPOFFER message
 216 // 'secs'     0 or seconds since    0 or seconds since    0 or seconds since    0                   0
 217 //            DHCP process started  DHCP process started  DHCP process started
 218 // 'flags'    Set 'BROADCAST'       Set 'BROADCAST'       Set 'BROADCAST'       0                   0
 219 //            flag if client        flag if client        flag if client
 220 //            requires broadcast    requires broadcast    requires broadcast
 221 //            reply                 reply                 reply
 222 // 'ciaddr'   0                     client's IP           0 or client's IP      0                   client's IP
 223 //                                                        (BOUND/RENEW/REBIND)
 224 // 'chaddr'   client's MAC          client's MAC          client's MAC          client's MAC        client's MAC
 225 // 'sname'    options or sname      options or sname      options or sname      (unused)            (unused)
 226 // 'file'     options or file       options or file       options or file       (unused)            (unused)
 227 // 'options'  options               options               options               message type opt    message type opt
 228 //
 229 // Option                     DHCPDISCOVER  DHCPINFORM  DHCPREQUEST      DHCPDECLINE  DHCPRELEASE
 230 // ------                     ------------  ----------  -----------      -----------  -----------
 231 // Requested IP address       MAY           MUST NOT    MUST (in         MUST         MUST NOT
 232 //                                                      SELECTING or
 233 //                                                      INIT-REBOOT)
 234 //                                                      MUST NOT (in
 235 //                                                      BOUND or
 236 //                                                      RENEWING)
 237 // IP address lease time      MAY           MUST NOT    MAY              MUST NOT     MUST NOT
 238 // Use 'file'/'sname' fields  MAY           MAY         MAY              MAY          MAY
 239 // Client identifier          MAY           MAY         MAY              MAY          MAY
 240 // Vendor class identifier    MAY           MAY         MAY              MUST NOT     MUST NOT
 241 // Server identifier          MUST NOT      MUST NOT    MUST (after      MUST         MUST
 242 //                                                      SELECTING)
 243 //                                                      MUST NOT (after
 244 //                                                      INIT-REBOOT,
 245 //                                                      BOUND, RENEWING
 246 //                                                      or REBINDING)
 247 // Parameter request list     MAY           MAY         MAY              MUST NOT     MUST NOT
 248 // Maximum message size       MAY           MAY         MAY              MUST NOT     MUST NOT
 249 // Message                    SHOULD NOT    SHOULD NOT  SHOULD NOT       SHOULD       SHOULD
 250 // Site-specific              MAY           MAY         MAY              MUST NOT     MUST NOT
 251 // All others                 MAY           MAY         MAY              MUST NOT     MUST NOT
 252
 253
 254 /*** Logging ***/
 255
 256 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
 257 # define IF_UDHCP_VERBOSE(...) __VA_ARGS__
 258 extern unsigned dhcp_verbose;
 259 # define log1(...) do { if (dhcp_verbose >= 1) bb_info_msg(__VA_ARGS__); } while (0)
 260 # if CONFIG_UDHCP_DEBUG >= 2
 261 void udhcp_dump_packet(struct dhcp_packet *packet) FAST_FUNC;
 262 #  define log2(...) do { if (dhcp_verbose >= 2) bb_info_msg(__VA_ARGS__); } while (0)
 263 # else
 264 #  define udhcp_dump_packet(...) ((void)0)
 265 #  define log2(...) ((void)0)
 266 # endif
 267 # if CONFIG_UDHCP_DEBUG >= 3
 268 #  define log3(...) do { if (dhcp_verbose >= 3) bb_info_msg(__VA_ARGS__); } while (0)
 269 # else
 270 #  define log3(...) ((void)0)
 271 # endif
 272 #else
 273 # define IF_UDHCP_VERBOSE(...)
 274 # define udhcp_dump_packet(...) ((void)0)
 275 # define log1(...) ((void)0)
 276 # define log2(...) ((void)0)
 277 # define log3(...) ((void)0)
 278 #endif
 279
 280
 281 /*** Other shared functions ***/
 282
 283 /* 2nd param is "uint32_t*" */
 284 int FAST_FUNC udhcp_str2nip(const char *str, void *arg);
 285 /* 2nd param is "struct option_set**" */
 286 int FAST_FUNC udhcp_str2optset(const char *str, void *arg);
 287
 288 void udhcp_init_header(struct dhcp_packet *packet, char type) FAST_FUNC;
 289
 290 int udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd) FAST_FUNC;
 291
 292 int udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
 293                 uint32_t source_nip, int source_port,
 294                 uint32_t dest_nip, int dest_port, const uint8_t *dest_arp,
 295                 int ifindex) FAST_FUNC;
 296
 297 int udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
 298                 uint32_t source_nip, int source_port,
 299                 uint32_t dest_nip, int dest_port) FAST_FUNC;
 300
 301 void udhcp_sp_setup(void) FAST_FUNC;
 302 int udhcp_sp_fd_set(fd_set *rfds, int extra_fd) FAST_FUNC;
 303 int udhcp_sp_read(const fd_set *rfds) FAST_FUNC;
 304
 305 int udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac, uint16_t *mtu) FAST_FUNC;
 306
 307 int udhcp_listen_socket(/*uint32_t ip,*/ int port, const char *inf) FAST_FUNC;
 308
 309 /* Returns 1 if no reply received */
 310 int arpping(uint32_t test_nip,
 311                 const uint8_t *safe_mac,
 312                 uint32_t from_ip,
 313                 uint8_t *from_mac,
 314                 const char *interface) FAST_FUNC;
 315
 316 /* note: ip is a pointer to an IPv6 in network order, possibly misaliged */
 317 int sprint_nip6(char *dest, /*const char *pre,*/ const uint8_t *ip) FAST_FUNC;
 318
 319 POP_SAVED_FUNCTION_VISIBILITY
 320
 321 #endif