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04158e0459
*: s/time(0)/time(NULL)/g
434 lines
11 KiB
C
434 lines
11 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* files.c -- DHCP server file manipulation *
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* Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
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*
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* Licensed under GPLv2, see file LICENSE in this tarball for details.
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*/
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#include <netinet/ether.h>
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#include "common.h"
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#include "dhcpd.h"
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#include "options.h"
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#if BB_LITTLE_ENDIAN
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static inline uint64_t hton64(uint64_t v)
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{
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return (((uint64_t)htonl(v)) << 32) | htonl(v >> 32);
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}
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#else
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#define hton64(v) (v)
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#endif
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#define ntoh64(v) hton64(v)
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/* on these functions, make sure your datatype matches */
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static int read_ip(const char *line, void *arg)
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{
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len_and_sockaddr *lsa;
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lsa = host_and_af2sockaddr(line, 0, AF_INET);
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if (!lsa)
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return 0;
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*(uint32_t*)arg = lsa->u.sin.sin_addr.s_addr;
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free(lsa);
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return 1;
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}
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static int read_mac(const char *line, void *arg)
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{
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return NULL == ether_aton_r(line, (struct ether_addr *)arg);
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}
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static int read_str(const char *line, void *arg)
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{
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char **dest = arg;
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free(*dest);
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*dest = xstrdup(line);
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return 1;
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}
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static int read_u32(const char *line, void *arg)
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{
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*(uint32_t*)arg = bb_strtou32(line, NULL, 10);
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return errno == 0;
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}
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static int read_yn(const char *line, void *arg)
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{
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char *dest = arg;
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if (!strcasecmp("yes", line)) {
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*dest = 1;
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return 1;
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}
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if (!strcasecmp("no", line)) {
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*dest = 0;
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return 1;
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}
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return 0;
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}
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/* find option 'code' in opt_list */
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struct option_set* FAST_FUNC find_option(struct option_set *opt_list, uint8_t code)
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{
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while (opt_list && opt_list->data[OPT_CODE] < code)
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opt_list = opt_list->next;
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if (opt_list && opt_list->data[OPT_CODE] == code)
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return opt_list;
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return NULL;
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}
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/* add an option to the opt_list */
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static void attach_option(struct option_set **opt_list,
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const struct dhcp_option *option, char *buffer, int length)
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{
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struct option_set *existing, *new, **curr;
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existing = find_option(*opt_list, option->code);
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if (!existing) {
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DEBUG("Attaching option %02x to list", option->code);
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#if ENABLE_FEATURE_UDHCP_RFC3397
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if ((option->flags & TYPE_MASK) == OPTION_STR1035)
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/* reuse buffer and length for RFC1035-formatted string */
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buffer = (char *)dname_enc(NULL, 0, buffer, &length);
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#endif
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/* make a new option */
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new = xmalloc(sizeof(*new));
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new->data = xmalloc(length + 2);
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new->data[OPT_CODE] = option->code;
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new->data[OPT_LEN] = length;
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memcpy(new->data + 2, buffer, length);
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curr = opt_list;
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while (*curr && (*curr)->data[OPT_CODE] < option->code)
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curr = &(*curr)->next;
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new->next = *curr;
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*curr = new;
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#if ENABLE_FEATURE_UDHCP_RFC3397
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if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
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free(buffer);
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#endif
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return;
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}
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/* add it to an existing option */
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DEBUG("Attaching option %02x to existing member of list", option->code);
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if (option->flags & OPTION_LIST) {
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#if ENABLE_FEATURE_UDHCP_RFC3397
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if ((option->flags & TYPE_MASK) == OPTION_STR1035)
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/* reuse buffer and length for RFC1035-formatted string */
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buffer = (char *)dname_enc(existing->data + 2,
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existing->data[OPT_LEN], buffer, &length);
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#endif
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if (existing->data[OPT_LEN] + length <= 255) {
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existing->data = xrealloc(existing->data,
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existing->data[OPT_LEN] + length + 3);
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if ((option->flags & TYPE_MASK) == OPTION_STRING) {
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/* ' ' can bring us to 256 - bad */
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if (existing->data[OPT_LEN] + length >= 255)
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return;
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/* add space separator between STRING options in a list */
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existing->data[existing->data[OPT_LEN] + 2] = ' ';
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existing->data[OPT_LEN]++;
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}
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memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
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existing->data[OPT_LEN] += length;
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} /* else, ignore the data, we could put this in a second option in the future */
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#if ENABLE_FEATURE_UDHCP_RFC3397
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if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
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free(buffer);
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#endif
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} /* else, ignore the new data */
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}
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/* read a dhcp option and add it to opt_list */
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static int read_opt(const char *const_line, void *arg)
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{
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struct option_set **opt_list = arg;
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char *opt, *val, *endptr;
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char *line;
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const struct dhcp_option *option;
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int retval, length, idx;
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char buffer[8] ALIGNED(4);
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uint16_t *result_u16 = (uint16_t *) buffer;
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uint32_t *result_u32 = (uint32_t *) buffer;
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/* Cheat, the only const line we'll actually get is "" */
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line = (char *) const_line;
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opt = strtok(line, " \t=");
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if (!opt)
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return 0;
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idx = index_in_strings(dhcp_option_strings, opt); /* NB: was strcasecmp! */
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if (idx < 0)
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return 0;
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option = &dhcp_options[idx];
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retval = 0;
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do {
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val = strtok(NULL, ", \t");
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if (!val) break;
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length = dhcp_option_lengths[option->flags & TYPE_MASK];
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retval = 0;
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opt = buffer; /* new meaning for variable opt */
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switch (option->flags & TYPE_MASK) {
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case OPTION_IP:
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retval = read_ip(val, buffer);
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break;
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case OPTION_IP_PAIR:
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retval = read_ip(val, buffer);
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val = strtok(NULL, ", \t/-");
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if (!val)
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retval = 0;
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if (retval)
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retval = read_ip(val, buffer + 4);
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break;
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case OPTION_STRING:
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#if ENABLE_FEATURE_UDHCP_RFC3397
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case OPTION_STR1035:
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#endif
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length = strlen(val);
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if (length > 0) {
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if (length > 254) length = 254;
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opt = val;
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retval = 1;
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}
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break;
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case OPTION_BOOLEAN:
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retval = read_yn(val, buffer);
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break;
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case OPTION_U8:
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buffer[0] = strtoul(val, &endptr, 0);
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retval = (endptr[0] == '\0');
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break;
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/* htonX are macros in older libc's, using temp var
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* in code below for safety */
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/* TODO: use bb_strtoX? */
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case OPTION_U16: {
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unsigned long tmp = strtoul(val, &endptr, 0);
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*result_u16 = htons(tmp);
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retval = (endptr[0] == '\0' /*&& tmp < 0x10000*/);
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break;
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}
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case OPTION_S16: {
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long tmp = strtol(val, &endptr, 0);
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*result_u16 = htons(tmp);
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retval = (endptr[0] == '\0');
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break;
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}
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case OPTION_U32: {
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unsigned long tmp = strtoul(val, &endptr, 0);
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*result_u32 = htonl(tmp);
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retval = (endptr[0] == '\0');
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break;
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}
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case OPTION_S32: {
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long tmp = strtol(val, &endptr, 0);
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*result_u32 = htonl(tmp);
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retval = (endptr[0] == '\0');
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break;
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}
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default:
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break;
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}
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if (retval)
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attach_option(opt_list, option, opt, length);
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} while (retval && option->flags & OPTION_LIST);
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return retval;
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}
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static int read_staticlease(const char *const_line, void *arg)
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{
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char *line;
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char *mac_string;
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char *ip_string;
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struct ether_addr mac_bytes;
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uint32_t ip;
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/* Read mac */
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line = (char *) const_line;
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mac_string = strtok_r(line, " \t", &line);
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read_mac(mac_string, &mac_bytes);
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/* Read ip */
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ip_string = strtok_r(NULL, " \t", &line);
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read_ip(ip_string, &ip);
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addStaticLease(arg, (uint8_t*) &mac_bytes, ip);
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if (ENABLE_UDHCP_DEBUG) printStaticLeases(arg);
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return 1;
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}
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struct config_keyword {
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const char *keyword;
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int (*handler)(const char *line, void *var);
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void *var;
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const char *def;
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};
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static const struct config_keyword keywords[] = {
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/* keyword handler variable address default */
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{"start", read_ip, &(server_config.start_ip), "192.168.0.20"},
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{"end", read_ip, &(server_config.end_ip), "192.168.0.254"},
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{"interface", read_str, &(server_config.interface), "eth0"},
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/* Avoid "max_leases value not sane" warning by setting default
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* to default_end_ip - default_start_ip + 1: */
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{"max_leases", read_u32, &(server_config.max_leases), "235"},
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// {"remaining", read_yn, &(server_config.remaining), "yes"},
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{"auto_time", read_u32, &(server_config.auto_time), "7200"},
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{"decline_time", read_u32, &(server_config.decline_time), "3600"},
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{"conflict_time",read_u32, &(server_config.conflict_time),"3600"},
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{"offer_time", read_u32, &(server_config.offer_time), "60"},
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{"min_lease", read_u32, &(server_config.min_lease), "60"},
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{"lease_file", read_str, &(server_config.lease_file), LEASES_FILE},
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{"pidfile", read_str, &(server_config.pidfile), "/var/run/udhcpd.pid"},
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{"siaddr", read_ip, &(server_config.siaddr), "0.0.0.0"},
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/* keywords with no defaults must be last! */
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{"option", read_opt, &(server_config.options), ""},
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{"opt", read_opt, &(server_config.options), ""},
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{"notify_file", read_str, &(server_config.notify_file), ""},
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{"sname", read_str, &(server_config.sname), ""},
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{"boot_file", read_str, &(server_config.boot_file), ""},
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{"static_lease", read_staticlease, &(server_config.static_leases), ""},
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};
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enum { KWS_WITH_DEFAULTS = ARRAY_SIZE(keywords) - 6 };
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void FAST_FUNC read_config(const char *file)
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{
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parser_t *parser;
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const struct config_keyword *k;
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unsigned i;
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char *token[2];
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for (i = 0; i < KWS_WITH_DEFAULTS; i++)
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keywords[i].handler(keywords[i].def, keywords[i].var);
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parser = config_open(file);
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while (config_read(parser, token, 2, 2, "# \t", PARSE_NORMAL)) {
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for (k = keywords, i = 0; i < ARRAY_SIZE(keywords); k++, i++) {
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if (!strcasecmp(token[0], k->keyword)) {
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if (!k->handler(token[1], k->var)) {
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bb_error_msg("can't parse line %u in %s",
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parser->lineno, file);
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/* reset back to the default value */
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k->handler(k->def, k->var);
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}
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break;
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}
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}
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}
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config_close(parser);
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server_config.start_ip = ntohl(server_config.start_ip);
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server_config.end_ip = ntohl(server_config.end_ip);
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}
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void FAST_FUNC write_leases(void)
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{
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int fd;
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unsigned i;
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leasetime_t curr;
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int64_t written_at;
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fd = open_or_warn(server_config.lease_file, O_WRONLY|O_CREAT|O_TRUNC);
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if (fd < 0)
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return;
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curr = written_at = time(NULL);
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written_at = hton64(written_at);
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full_write(fd, &written_at, sizeof(written_at));
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for (i = 0; i < server_config.max_leases; i++) {
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leasetime_t tmp_time;
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if (leases[i].yiaddr == 0)
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continue;
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/* Screw with the time in the struct, for easier writing */
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tmp_time = leases[i].expires;
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leases[i].expires -= curr;
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if ((signed_leasetime_t) leases[i].expires < 0)
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leases[i].expires = 0;
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leases[i].expires = htonl(leases[i].expires);
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/* No error check. If the file gets truncated,
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* we lose some leases on restart. Oh well. */
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full_write(fd, &leases[i], sizeof(leases[i]));
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/* Then restore it when done */
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leases[i].expires = tmp_time;
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}
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close(fd);
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if (server_config.notify_file) {
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// TODO: vfork-based child creation
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char *cmd = xasprintf("%s %s", server_config.notify_file, server_config.lease_file);
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system(cmd);
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free(cmd);
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}
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}
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void FAST_FUNC read_leases(const char *file)
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{
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struct dhcpOfferedAddr lease;
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int64_t written_at, time_passed;
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int fd;
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USE_UDHCP_DEBUG(unsigned i;)
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fd = open_or_warn(file, O_RDONLY);
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if (fd < 0)
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return;
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if (full_read(fd, &written_at, sizeof(written_at)) != sizeof(written_at))
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goto ret;
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written_at = ntoh64(written_at);
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time_passed = time(NULL) - written_at;
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/* Strange written_at, or lease file from old version of udhcpd
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* which had no "written_at" field? */
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if ((uint64_t)time_passed > 12 * 60 * 60)
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goto ret;
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USE_UDHCP_DEBUG(i = 0;)
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while (full_read(fd, &lease, sizeof(lease)) == sizeof(lease)) {
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/* ADDME: what if it matches some static lease? */
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uint32_t y = ntohl(lease.yiaddr);
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if (y >= server_config.start_ip && y <= server_config.end_ip) {
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signed_leasetime_t expires = ntohl(lease.expires) - (signed_leasetime_t)time_passed;
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if (expires <= 0)
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continue;
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/* NB: add_lease takes "relative time", IOW,
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* lease duration, not lease deadline. */
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if (!(add_lease(lease.chaddr, lease.yiaddr, expires))) {
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bb_error_msg("too many leases while loading %s", file);
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break;
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}
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USE_UDHCP_DEBUG(i++;)
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}
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}
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DEBUG("Read %d leases", i);
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ret:
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close(fd);
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}
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