"Robert P. J. Day" | 63fc1a9 | 2006-07-02 19:47:05 +0000 | [diff] [blame] | 1 | /* vi: set sw=4 ts=4: */ |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 2 | /* |
| 3 | * options.c -- DHCP server option packet tools |
| 4 | * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001 |
| 5 | */ |
| 6 | |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 7 | #include "common.h" |
| 8 | #include "dhcpd.h" |
| 9 | #include "options.h" |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 10 | |
| 11 | |
| 12 | /* supported options are easily added here */ |
Denis Vlasenko | c90c3f3 | 2006-11-23 12:57:49 +0000 | [diff] [blame] | 13 | const struct dhcp_option dhcp_options[] = { |
Denis Vlasenko | 5066473 | 2007-02-27 21:15:08 +0000 | [diff] [blame] | 14 | /* name[12] flags code */ |
Denis Vlasenko | c90c3f3 | 2006-11-23 12:57:49 +0000 | [diff] [blame] | 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}, |
Denis Vlasenko | c4d606e | 2007-02-02 01:16:08 +0000 | [diff] [blame] | 26 | {"domain", OPTION_STRING | OPTION_LIST | OPTION_REQ, 0x0f}, |
Denis Vlasenko | c90c3f3 | 2006-11-23 12:57:49 +0000 | [diff] [blame] | 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}, |
Denis Vlasenko | e175ff2 | 2006-09-26 17:41:00 +0000 | [diff] [blame] | 41 | {"vendorclass", OPTION_STRING, 0x3C}, |
| 42 | {"clientid", OPTION_STRING, 0x3D}, |
Denis Vlasenko | c90c3f3 | 2006-11-23 12:57:49 +0000 | [diff] [blame] | 43 | {"tftp", OPTION_STRING, 0x42}, |
| 44 | {"bootfile", OPTION_STRING, 0x43}, |
Denis Vlasenko | e175ff2 | 2006-09-26 17:41:00 +0000 | [diff] [blame] | 45 | {"userclass", OPTION_STRING, 0x4D}, |
Denis Vlasenko | 5066473 | 2007-02-27 21:15:08 +0000 | [diff] [blame] | 46 | #if ENABLE_FEATURE_RFC3397 |
| 47 | {"search", OPTION_STR1035 | OPTION_LIST | OPTION_REQ, 0x77}, |
| 48 | #endif |
Denis Vlasenko | c90c3f3 | 2006-11-23 12:57:49 +0000 | [diff] [blame] | 49 | /* MSIE's "Web Proxy Autodiscovery Protocol" support */ |
| 50 | {"wpad", OPTION_STRING, 0xfc}, |
| 51 | {"", 0x00, 0x00} |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 52 | }; |
| 53 | |
| 54 | /* Lengths of the different option types */ |
Denis Vlasenko | 6ca409e | 2007-08-12 20:58:27 +0000 | [diff] [blame] | 55 | const unsigned char option_lengths[] ALIGN1 = { |
Denis Vlasenko | c90c3f3 | 2006-11-23 12:57:49 +0000 | [diff] [blame] | 56 | [OPTION_IP] = 4, |
| 57 | [OPTION_IP_PAIR] = 8, |
| 58 | [OPTION_BOOLEAN] = 1, |
| 59 | [OPTION_STRING] = 1, |
Denis Vlasenko | 5066473 | 2007-02-27 21:15:08 +0000 | [diff] [blame] | 60 | #if ENABLE_FEATURE_RFC3397 |
| 61 | [OPTION_STR1035] = 1, |
| 62 | #endif |
Denis Vlasenko | c90c3f3 | 2006-11-23 12:57:49 +0000 | [diff] [blame] | 63 | [OPTION_U8] = 1, |
| 64 | [OPTION_U16] = 2, |
| 65 | [OPTION_S16] = 2, |
| 66 | [OPTION_U32] = 4, |
| 67 | [OPTION_S32] = 4 |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 68 | }; |
| 69 | |
| 70 | |
| 71 | /* get an option with bounds checking (warning, not aligned). */ |
| 72 | uint8_t *get_option(struct dhcpMessage *packet, int code) |
| 73 | { |
| 74 | int i, length; |
| 75 | uint8_t *optionptr; |
Denis Vlasenko | 6884f66 | 2007-11-23 00:08:54 +0000 | [diff] [blame] | 76 | int over = 0; |
| 77 | int curr = OPTION_FIELD; |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 78 | |
| 79 | optionptr = packet->options; |
| 80 | i = 0; |
Denis Vlasenko | 6884f66 | 2007-11-23 00:08:54 +0000 | [diff] [blame] | 81 | length = sizeof(packet->options); |
| 82 | while (1) { |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 83 | if (i >= length) { |
Denis Vlasenko | e1a0d48 | 2006-10-20 13:28:22 +0000 | [diff] [blame] | 84 | bb_error_msg("bogus packet, option fields too long"); |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 85 | return NULL; |
| 86 | } |
| 87 | if (optionptr[i + OPT_CODE] == code) { |
| 88 | if (i + 1 + optionptr[i + OPT_LEN] >= length) { |
Denis Vlasenko | e1a0d48 | 2006-10-20 13:28:22 +0000 | [diff] [blame] | 89 | bb_error_msg("bogus packet, option fields too long"); |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 90 | return NULL; |
| 91 | } |
| 92 | return optionptr + i + 2; |
| 93 | } |
| 94 | switch (optionptr[i + OPT_CODE]) { |
| 95 | case DHCP_PADDING: |
| 96 | i++; |
| 97 | break; |
| 98 | case DHCP_OPTION_OVER: |
| 99 | if (i + 1 + optionptr[i + OPT_LEN] >= length) { |
Denis Vlasenko | e1a0d48 | 2006-10-20 13:28:22 +0000 | [diff] [blame] | 100 | bb_error_msg("bogus packet, option fields too long"); |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 101 | return NULL; |
| 102 | } |
| 103 | over = optionptr[i + 3]; |
| 104 | i += optionptr[OPT_LEN] + 2; |
| 105 | break; |
| 106 | case DHCP_END: |
Denis Vlasenko | 6884f66 | 2007-11-23 00:08:54 +0000 | [diff] [blame] | 107 | if (curr == OPTION_FIELD && (over & FILE_FIELD)) { |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 108 | optionptr = packet->file; |
| 109 | i = 0; |
Denis Vlasenko | 6884f66 | 2007-11-23 00:08:54 +0000 | [diff] [blame] | 110 | length = sizeof(packet->file); |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 111 | curr = FILE_FIELD; |
Denis Vlasenko | 6884f66 | 2007-11-23 00:08:54 +0000 | [diff] [blame] | 112 | } else if (curr == FILE_FIELD && (over & SNAME_FIELD)) { |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 113 | optionptr = packet->sname; |
| 114 | i = 0; |
Denis Vlasenko | 6884f66 | 2007-11-23 00:08:54 +0000 | [diff] [blame] | 115 | length = sizeof(packet->sname); |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 116 | curr = SNAME_FIELD; |
Denis Vlasenko | 6884f66 | 2007-11-23 00:08:54 +0000 | [diff] [blame] | 117 | } else |
| 118 | return NULL; |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 119 | break; |
| 120 | default: |
| 121 | i += optionptr[OPT_LEN + i] + 2; |
| 122 | } |
| 123 | } |
| 124 | return NULL; |
| 125 | } |
| 126 | |
| 127 | |
| 128 | /* return the position of the 'end' option (no bounds checking) */ |
| 129 | int end_option(uint8_t *optionptr) |
| 130 | { |
| 131 | int i = 0; |
| 132 | |
| 133 | while (optionptr[i] != DHCP_END) { |
| 134 | if (optionptr[i] == DHCP_PADDING) i++; |
| 135 | else i += optionptr[i + OPT_LEN] + 2; |
| 136 | } |
| 137 | return i; |
| 138 | } |
| 139 | |
| 140 | |
| 141 | /* add an option string to the options (an option string contains an option code, |
| 142 | * length, then data) */ |
| 143 | int add_option_string(uint8_t *optionptr, uint8_t *string) |
| 144 | { |
| 145 | int end = end_option(optionptr); |
| 146 | |
| 147 | /* end position + string length + option code/length + end option */ |
Denis Vlasenko | 72e7604 | 2007-11-25 03:15:24 +0000 | [diff] [blame^] | 148 | if (end + string[OPT_LEN] + 2 + 1 >= DHCP_OPTIONS_BUFSIZE) { |
Denis Vlasenko | e1a0d48 | 2006-10-20 13:28:22 +0000 | [diff] [blame] | 149 | bb_error_msg("option 0x%02x did not fit into the packet", |
Denis Vlasenko | 3538b9a | 2006-09-06 18:36:50 +0000 | [diff] [blame] | 150 | string[OPT_CODE]); |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 151 | return 0; |
| 152 | } |
Denis Vlasenko | 3538b9a | 2006-09-06 18:36:50 +0000 | [diff] [blame] | 153 | DEBUG("adding option 0x%02x", string[OPT_CODE]); |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 154 | memcpy(optionptr + end, string, string[OPT_LEN] + 2); |
| 155 | optionptr[end + string[OPT_LEN] + 2] = DHCP_END; |
| 156 | return string[OPT_LEN] + 2; |
| 157 | } |
| 158 | |
| 159 | |
| 160 | /* add a one to four byte option to a packet */ |
| 161 | int add_simple_option(uint8_t *optionptr, uint8_t code, uint32_t data) |
| 162 | { |
Denis Vlasenko | c90c3f3 | 2006-11-23 12:57:49 +0000 | [diff] [blame] | 163 | const struct dhcp_option *dh; |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 164 | |
Denis Vlasenko | c90c3f3 | 2006-11-23 12:57:49 +0000 | [diff] [blame] | 165 | for (dh = dhcp_options; dh->code; dh++) { |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 166 | if (dh->code == code) { |
| 167 | uint8_t option[6], len; |
| 168 | |
| 169 | option[OPT_CODE] = code; |
| 170 | len = option_lengths[dh->flags & TYPE_MASK]; |
| 171 | option[OPT_LEN] = len; |
Rob Landley | c8b360e | 2006-05-31 22:24:33 +0000 | [diff] [blame] | 172 | if (BB_BIG_ENDIAN) data <<= 8 * (4 - len); |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 173 | /* This memcpy is for broken processors which can't |
| 174 | * handle a simple unaligned 32-bit assignment */ |
| 175 | memcpy(&option[OPT_DATA], &data, 4); |
| 176 | return add_option_string(optionptr, option); |
| 177 | } |
| 178 | } |
| 179 | |
Denis Vlasenko | ea62077 | 2006-10-14 02:23:43 +0000 | [diff] [blame] | 180 | bb_error_msg("cannot add option 0x%02x", code); |
Mike Frysinger | 7031f62 | 2006-05-08 03:20:50 +0000 | [diff] [blame] | 181 | return 0; |
| 182 | } |