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217 lines
6.2 KiB
C
217 lines
6.2 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* DHCP server config and lease file manipulation
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*
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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 source tree.
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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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/* on these functions, make sure your datatype matches */
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static int FAST_FUNC 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 FAST_FUNC 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 FAST_FUNC 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; /* it's "struct { uint8_t mac[6]; }" */
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uint32_t nip;
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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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if (!mac_string || !ether_aton_r(mac_string, &mac_bytes))
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return 0;
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/* Read ip */
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ip_string = strtok_r(NULL, " \t", &line);
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if (!ip_string || !udhcp_str2nip(ip_string, &nip))
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return 0;
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add_static_lease(arg, (uint8_t*) &mac_bytes, nip);
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log_static_leases(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) FAST_FUNC;
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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" , udhcp_str2nip , &server_config.start_ip , "192.168.0.20"},
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{"end" , udhcp_str2nip , &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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{"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_sec, "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" , udhcp_str2nip , &server_config.siaddr_nip , "0.0.0.0"},
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/* keywords with no defaults must be last! */
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{"option" , udhcp_str2optset, &server_config.options , ""},
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{"opt" , udhcp_str2optset, &server_config.options , ""},
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{"notify_file" , read_str , &server_config.notify_file , NULL},
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{"sname" , read_str , &server_config.sname , NULL},
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{"boot_file" , read_str , &server_config.boot_file , NULL},
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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) == 0) {
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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 = SWAP_BE64(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 (g_leases[i].lease_nip == 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 = g_leases[i].expires;
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g_leases[i].expires -= curr;
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if ((signed_leasetime_t) g_leases[i].expires < 0)
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g_leases[i].expires = 0;
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g_leases[i].expires = htonl(g_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, &g_leases[i], sizeof(g_leases[i]));
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/* Then restore it when done */
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g_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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char *argv[3];
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argv[0] = server_config.notify_file;
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argv[1] = server_config.lease_file;
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argv[2] = NULL;
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spawn_and_wait(argv);
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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 dyn_lease lease;
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int64_t written_at, time_passed;
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int fd;
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#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
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unsigned i = 0;
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#endif
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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 = SWAP_BE64(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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while (full_read(fd, &lease, sizeof(lease)) == sizeof(lease)) {
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//FIXME: what if it matches some static lease?
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uint32_t y = ntohl(lease.lease_nip);
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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.lease_mac, lease.lease_nip,
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expires,
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lease.hostname, sizeof(lease.hostname)
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) == 0
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) {
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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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#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
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i++;
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#endif
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}
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}
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log1("Read %d leases", i);
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ret:
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close(fd);
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}
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