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    Contents of /trunk/mkinitrd-magellan/busybox/networking/udhcp/options.c

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    Revision 532 - (show annotations) (download)
    Sat Sep 1 22:45:15 2007 UTC (16 years, 8 months ago) by niro
    File MIME type: text/plain
    File size: 5618 byte(s) 
    -import if magellan mkinitrd; it is a fork of redhats mkinitrd-5.0.8 with all magellan patches and features; deprecates magellan-src/mkinitrd
    1 /* vi: set sw=4 ts=4: */
    2 /*
    3 * options.c -- DHCP server option packet tools
    4 * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
    5 */
    6
    7 #include "common.h"
    8 #include "dhcpd.h"
    9 #include "options.h"
    10
    11
    12 /* supported options are easily added here */
    13 const struct dhcp_option dhcp_options[] = {
    14 /* name[10] flags code */
    15 {"subnet", OPTION_IP | OPTION_REQ, 0x01},
    16 {"timezone", OPTION_S32, 0x02},
    17 {"router", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03},
    18 {"timesvr", OPTION_IP | OPTION_LIST, 0x04},
    19 {"namesvr", OPTION_IP | OPTION_LIST, 0x05},
    20 {"dns", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06},
    21 {"logsvr", OPTION_IP | OPTION_LIST, 0x07},
    22 {"cookiesvr", OPTION_IP | OPTION_LIST, 0x08},
    23 {"lprsvr", OPTION_IP | OPTION_LIST, 0x09},
    24 {"hostname", OPTION_STRING | OPTION_REQ, 0x0c},
    25 {"bootsize", OPTION_U16, 0x0d},
    26 {"domain", OPTION_STRING | OPTION_REQ, 0x0f},
    27 {"swapsvr", OPTION_IP, 0x10},
    28 {"rootpath", OPTION_STRING, 0x11},
    29 {"ipttl", OPTION_U8, 0x17},
    30 {"mtu", OPTION_U16, 0x1a},
    31 {"broadcast", OPTION_IP | OPTION_REQ, 0x1c},
    32 {"nisdomain", OPTION_STRING | OPTION_REQ, 0x28},
    33 {"nissrv", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x29},
    34 {"ntpsrv", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x2a},
    35 {"wins", OPTION_IP | OPTION_LIST, 0x2c},
    36 {"requestip", OPTION_IP, 0x32},
    37 {"lease", OPTION_U32, 0x33},
    38 {"dhcptype", OPTION_U8, 0x35},
    39 {"serverid", OPTION_IP, 0x36},
    40 {"message", OPTION_STRING, 0x38},
    41 {"vendorclass", OPTION_STRING, 0x3C},
    42 {"clientid", OPTION_STRING, 0x3D},
    43 {"tftp", OPTION_STRING, 0x42},
    44 {"bootfile", OPTION_STRING, 0x43},
    45 {"userclass", OPTION_STRING, 0x4D},
    46 /* MSIE's "Web Proxy Autodiscovery Protocol" support */
    47 {"wpad", OPTION_STRING, 0xfc},
    48 {"", 0x00, 0x00}
    49 };
    50
    51 /* Lengths of the different option types */
    52 const unsigned char option_lengths[] = {
    53 [OPTION_IP] = 4,
    54 [OPTION_IP_PAIR] = 8,
    55 [OPTION_BOOLEAN] = 1,
    56 [OPTION_STRING] = 1,
    57 [OPTION_U8] = 1,
    58 [OPTION_U16] = 2,
    59 [OPTION_S16] = 2,
    60 [OPTION_U32] = 4,
    61 [OPTION_S32] = 4
    62 };
    63
    64
    65 /* get an option with bounds checking (warning, not aligned). */
    66 uint8_t *get_option(struct dhcpMessage *packet, int code)
    67 {
    68 int i, length;
    69 uint8_t *optionptr;
    70 int over = 0, done = 0, curr = OPTION_FIELD;
    71
    72 optionptr = packet->options;
    73 i = 0;
    74 length = 308;
    75 while (!done) {
    76 if (i >= length) {
    77 bb_error_msg("bogus packet, option fields too long");
    78 return NULL;
    79 }
    80 if (optionptr[i + OPT_CODE] == code) {
    81 if (i + 1 + optionptr[i + OPT_LEN] >= length) {
    82 bb_error_msg("bogus packet, option fields too long");
    83 return NULL;
    84 }
    85 return optionptr + i + 2;
    86 }
    87 switch (optionptr[i + OPT_CODE]) {
    88 case DHCP_PADDING:
    89 i++;
    90 break;
    91 case DHCP_OPTION_OVER:
    92 if (i + 1 + optionptr[i + OPT_LEN] >= length) {
    93 bb_error_msg("bogus packet, option fields too long");
    94 return NULL;
    95 }
    96 over = optionptr[i + 3];
    97 i += optionptr[OPT_LEN] + 2;
    98 break;
    99 case DHCP_END:
    100 if (curr == OPTION_FIELD && over & FILE_FIELD) {
    101 optionptr = packet->file;
    102 i = 0;
    103 length = 128;
    104 curr = FILE_FIELD;
    105 } else if (curr == FILE_FIELD && over & SNAME_FIELD) {
    106 optionptr = packet->sname;
    107 i = 0;
    108 length = 64;
    109 curr = SNAME_FIELD;
    110 } else done = 1;
    111 break;
    112 default:
    113 i += optionptr[OPT_LEN + i] + 2;
    114 }
    115 }
    116 return NULL;
    117 }
    118
    119
    120 /* return the position of the 'end' option (no bounds checking) */
    121 int end_option(uint8_t *optionptr)
    122 {
    123 int i = 0;
    124
    125 while (optionptr[i] != DHCP_END) {
    126 if (optionptr[i] == DHCP_PADDING) i++;
    127 else i += optionptr[i + OPT_LEN] + 2;
    128 }
    129 return i;
    130 }
    131
    132
    133 /* add an option string to the options (an option string contains an option code,
    134 * length, then data) */
    135 int add_option_string(uint8_t *optionptr, uint8_t *string)
    136 {
    137 int end = end_option(optionptr);
    138
    139 /* end position + string length + option code/length + end option */
    140 if (end + string[OPT_LEN] + 2 + 1 >= 308) {
    141 bb_error_msg("option 0x%02x did not fit into the packet",
    142 string[OPT_CODE]);
    143 return 0;
    144 }
    145 DEBUG("adding option 0x%02x", string[OPT_CODE]);
    146 memcpy(optionptr + end, string, string[OPT_LEN] + 2);
    147 optionptr[end + string[OPT_LEN] + 2] = DHCP_END;
    148 return string[OPT_LEN] + 2;
    149 }
    150
    151
    152 /* add a one to four byte option to a packet */
    153 int add_simple_option(uint8_t *optionptr, uint8_t code, uint32_t data)
    154 {
    155 const struct dhcp_option *dh;
    156
    157 for (dh = dhcp_options; dh->code; dh++) {
    158 if (dh->code == code) {
    159 uint8_t option[6], len;
    160
    161 option[OPT_CODE] = code;
    162 len = option_lengths[dh->flags & TYPE_MASK];
    163 option[OPT_LEN] = len;
    164 if (BB_BIG_ENDIAN) data <<= 8 * (4 - len);
    165 /* This memcpy is for broken processors which can't
    166 * handle a simple unaligned 32-bit assignment */
    167 memcpy(&option[OPT_DATA], &data, 4);
    168 return add_option_string(optionptr, option);
    169 }
    170 }
    171
    172 bb_error_msg("cannot add option 0x%02x", code);
    173 return 0;
    174 }