2 * options.c -- DHCP server option packet tools
3 * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
15 /* supported options are easily added here */
16 struct dhcp_option dhcp_options[] = {
17 /* name[10] flags code */
18 {"subnet", OPTION_IP | OPTION_REQ, 0x01},
19 {"timezone", OPTION_S32, 0x02},
20 {"router", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03},
21 {"timesvr", OPTION_IP | OPTION_LIST, 0x04},
22 {"namesvr", OPTION_IP | OPTION_LIST, 0x05},
23 {"dns", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06},
24 {"logsvr", OPTION_IP | OPTION_LIST, 0x07},
25 {"cookiesvr", OPTION_IP | OPTION_LIST, 0x08},
26 {"lprsvr", OPTION_IP | OPTION_LIST, 0x09},
27 {"hostname", OPTION_STRING | OPTION_REQ, 0x0c},
28 {"bootsize", OPTION_U16, 0x0d},
29 {"domain", OPTION_STRING | OPTION_REQ, 0x0f},
30 {"swapsvr", OPTION_IP, 0x10},
31 //We had the possibility for the client to ask for a rootpath
32 //closes http://bugs.debian.org/279110 (ericvb@debian.org)
33 //{"rootpath", OPTION_STRING, 0x11},
34 {"rootpath", OPTION_STRING | OPTION_REQ, 0x11},
35 {"ipttl", OPTION_U8, 0x17},
36 {"mtu", OPTION_U16, 0x1a},
37 {"broadcast", OPTION_IP | OPTION_REQ, 0x1c},
38 {"nisdomain", OPTION_STRING | OPTION_REQ, 0x28},
39 {"nissrv", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x29},
40 {"ntpsrv", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x2a},
41 {"wins", OPTION_IP | OPTION_LIST, 0x2c},
42 {"requestip", OPTION_IP, 0x32},
43 {"lease", OPTION_U32, 0x33},
44 {"dhcptype", OPTION_U8, 0x35},
45 {"serverid", OPTION_IP, 0x36},
46 {"message", OPTION_STRING, 0x38},
47 {"tftp", OPTION_STRING, 0x42},
48 {"bootfile", OPTION_STRING, 0x43},
49 {"wpad", OPTION_STRING, 0xfc},
53 /* Lengths of the different option types */
54 int option_lengths[] = {
67 /* get an option with bounds checking (warning, not aligned). */
68 uint8_t *get_option(struct dhcpMessage *packet, int code)
72 int over = 0, done = 0, curr = OPTION_FIELD;
74 optionptr = packet->options;
79 LOG(LOG_WARNING, "bogus packet, option fields too long.");
82 if (optionptr[i + OPT_CODE] == code) {
83 if (i + 1 + optionptr[i + OPT_LEN] >= length) {
84 LOG(LOG_WARNING, "bogus packet, option fields too long.");
87 return optionptr + i + 2;
89 switch (optionptr[i + OPT_CODE]) {
93 case DHCP_OPTION_OVER:
94 if (i + 1 + optionptr[i + OPT_LEN] >= length) {
95 LOG(LOG_WARNING, "bogus packet, option fields too long.");
98 over = optionptr[i + 3];
99 i += optionptr[OPT_LEN] + 2;
102 if (curr == OPTION_FIELD && over & FILE_FIELD) {
103 optionptr = packet->file;
107 } else if (curr == FILE_FIELD && over & SNAME_FIELD) {
108 optionptr = packet->sname;
115 i += optionptr[OPT_LEN + i] + 2;
122 /* return the position of the 'end' option (no bounds checking) */
123 int end_option(uint8_t *optionptr)
127 while (optionptr[i] != DHCP_END) {
128 if (optionptr[i] == DHCP_PADDING) i++;
129 else i += optionptr[i + OPT_LEN] + 2;
135 /* add an option string to the options (an option string contains an option code,
136 * length, then data) */
137 int add_option_string(uint8_t *optionptr, uint8_t *string)
139 int end = end_option(optionptr);
141 /* end position + string length + option code/length + end option */
142 if (end + string[OPT_LEN] + 2 + 1 >= 308) {
143 LOG(LOG_ERR, "Option 0x%02x did not fit into the packet!", string[OPT_CODE]);
146 DEBUG(LOG_INFO, "adding option 0x%02x", string[OPT_CODE]);
147 memcpy(optionptr + end, string, string[OPT_LEN] + 2);
148 optionptr[end + string[OPT_LEN] + 2] = DHCP_END;
149 return string[OPT_LEN] + 2;
153 /* add a one to four byte option to a packet */
154 int add_simple_option(uint8_t *optionptr, uint8_t code, uint32_t data)
158 uint8_t option[2 + 4];
163 u8 = (uint8_t *) &aligned;
164 u16 = (uint16_t *) &aligned;
167 for (i = 0; dhcp_options[i].code; i++)
168 if (dhcp_options[i].code == code) {
169 length = option_lengths[dhcp_options[i].flags & TYPE_MASK];
173 DEBUG(LOG_ERR, "Could not add option 0x%02x", code);
177 option[OPT_CODE] = code;
178 option[OPT_LEN] = length;
181 case 1: *u8 = data; break;
182 case 2: *u16 = data; break;
183 case 4: *u32 = data; break;
185 memcpy(option + 2, &aligned, length);
186 return add_option_string(optionptr, option);
190 /* find option 'code' in opt_list */
191 struct option_set *find_option(struct option_set *opt_list, char code)
193 while (opt_list && opt_list->data[OPT_CODE] < code)
194 opt_list = opt_list->next;
196 if (opt_list && opt_list->data[OPT_CODE] == code) return opt_list;
201 /* add an option to the opt_list */
202 void attach_option(struct option_set **opt_list, struct dhcp_option *option, char *buffer, int length)
204 struct option_set *existing, *new, **curr;
206 /* add it to an existing option */
207 if ((existing = find_option(*opt_list, option->code))) {
208 DEBUG(LOG_INFO, "Attaching option %s to existing member of list", option->name);
209 if (option->flags & OPTION_LIST) {
210 if (existing->data[OPT_LEN] + length <= 255) {
211 existing->data = realloc(existing->data,
212 existing->data[OPT_LEN] + length + 2);
213 memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
214 existing->data[OPT_LEN] += length;
215 } /* else, ignore the data, we could put this in a second option in the future */
216 } /* else, ignore the new data */
218 DEBUG(LOG_INFO, "Attaching option %s to list", option->name);
220 /* make a new option */
221 new = xmalloc(sizeof(struct option_set));
222 new->data = xmalloc(length + 2);
223 new->data[OPT_CODE] = option->code;
224 new->data[OPT_LEN] = length;
225 memcpy(new->data + 2, buffer, length);
228 while (*curr && (*curr)->data[OPT_CODE] < option->code)
229 curr = &(*curr)->next;