busybox/networking/udhcp/files.c
Denys Vlasenko 0f62c4d065 udhcpd: remove five more options which do not make sense or not supported
requestip, vendorclass, clientid are client-side variables,
          they do not make sense as udhcpd opts
dhcptype  is the packet type (not interesting, it's always 5)
userclass needs parser support in order to work

function                                             old     new   delta
dhcp_options                                          68      66      -2
read_opt                                             865     859      -6
dhcp_option_strings                                  253     203     -50
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-58)             Total: -58 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2010-03-20 07:12:21 +01:00

439 lines
11 KiB
C

/* vi: set sw=4 ts=4: */
/*
* files.c -- DHCP server file manipulation *
* Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
*
* Licensed under GPLv2, see file LICENSE in this tarball for details.
*/
#include <netinet/ether.h>
#include "common.h"
#include "dhcpd.h"
#include "options.h"
#if BB_LITTLE_ENDIAN
static inline uint64_t hton64(uint64_t v)
{
return (((uint64_t)htonl(v)) << 32) | htonl(v >> 32);
}
#else
#define hton64(v) (v)
#endif
#define ntoh64(v) hton64(v)
/* on these functions, make sure your datatype matches */
static int FAST_FUNC read_nip(const char *line, void *arg)
{
len_and_sockaddr *lsa;
lsa = host_and_af2sockaddr(line, 0, AF_INET);
if (!lsa)
return 0;
*(uint32_t*)arg = lsa->u.sin.sin_addr.s_addr;
free(lsa);
return 1;
}
static int FAST_FUNC read_mac(const char *line, void *arg)
{
return NULL == ether_aton_r(line, (struct ether_addr *)arg);
}
static int FAST_FUNC read_str(const char *line, void *arg)
{
char **dest = arg;
free(*dest);
*dest = xstrdup(line);
return 1;
}
static int FAST_FUNC read_u32(const char *line, void *arg)
{
*(uint32_t*)arg = bb_strtou32(line, NULL, 10);
return errno == 0;
}
static int FAST_FUNC read_yn(const char *line, void *arg)
{
char *dest = arg;
if (!strcasecmp("yes", line)) {
*dest = 1;
return 1;
}
if (!strcasecmp("no", line)) {
*dest = 0;
return 1;
}
return 0;
}
/* find option 'code' in opt_list */
struct option_set* FAST_FUNC find_option(struct option_set *opt_list, uint8_t code)
{
while (opt_list && opt_list->data[OPT_CODE] < code)
opt_list = opt_list->next;
if (opt_list && opt_list->data[OPT_CODE] == code)
return opt_list;
return NULL;
}
/* add an option to the opt_list */
static void attach_option(struct option_set **opt_list,
const struct dhcp_option *option, char *buffer, int length)
{
struct option_set *existing, *new, **curr;
existing = find_option(*opt_list, option->code);
if (!existing) {
log2("Attaching option %02x to list", option->code);
#if ENABLE_FEATURE_UDHCP_RFC3397
if ((option->flags & TYPE_MASK) == OPTION_STR1035)
/* reuse buffer and length for RFC1035-formatted string */
buffer = (char *)dname_enc(NULL, 0, buffer, &length);
#endif
/* make a new option */
new = xmalloc(sizeof(*new));
new->data = xmalloc(length + 2);
new->data[OPT_CODE] = option->code;
new->data[OPT_LEN] = length;
memcpy(new->data + 2, buffer, length);
curr = opt_list;
while (*curr && (*curr)->data[OPT_CODE] < option->code)
curr = &(*curr)->next;
new->next = *curr;
*curr = new;
#if ENABLE_FEATURE_UDHCP_RFC3397
if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
free(buffer);
#endif
return;
}
/* add it to an existing option */
log1("Attaching option %02x to existing member of list", option->code);
if (option->flags & OPTION_LIST) {
#if ENABLE_FEATURE_UDHCP_RFC3397
if ((option->flags & TYPE_MASK) == OPTION_STR1035)
/* reuse buffer and length for RFC1035-formatted string */
buffer = (char *)dname_enc(existing->data + 2,
existing->data[OPT_LEN], buffer, &length);
#endif
if (existing->data[OPT_LEN] + length <= 255) {
existing->data = xrealloc(existing->data,
existing->data[OPT_LEN] + length + 3);
if ((option->flags & TYPE_MASK) == OPTION_STRING) {
/* ' ' can bring us to 256 - bad */
if (existing->data[OPT_LEN] + length >= 255)
return;
/* add space separator between STRING options in a list */
existing->data[existing->data[OPT_LEN] + 2] = ' ';
existing->data[OPT_LEN]++;
}
memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
existing->data[OPT_LEN] += length;
} /* else, ignore the data, we could put this in a second option in the future */
#if ENABLE_FEATURE_UDHCP_RFC3397
if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
free(buffer);
#endif
} /* else, ignore the new data */
}
/* read a dhcp option and add it to opt_list */
static int FAST_FUNC read_opt(const char *const_line, void *arg)
{
struct option_set **opt_list = arg;
char *opt, *val, *endptr;
char *line;
const struct dhcp_option *option;
int retval, length, idx;
char buffer[8] ALIGNED(4);
uint16_t *result_u16 = (uint16_t *) buffer;
uint32_t *result_u32 = (uint32_t *) buffer;
/* Cheat, the only const line we'll actually get is "" */
line = (char *) const_line;
opt = strtok(line, " \t=");
if (!opt)
return 0;
idx = index_in_strings(dhcp_option_strings, opt); /* NB: was strcasecmp! */
if (idx < 0)
return 0;
option = &dhcp_options[idx];
retval = 0;
do {
val = strtok(NULL, ", \t");
if (!val) break;
length = dhcp_option_lengths[option->flags & TYPE_MASK];
retval = 0;
opt = buffer; /* new meaning for variable opt */
switch (option->flags & TYPE_MASK) {
case OPTION_IP:
retval = read_nip(val, buffer);
break;
case OPTION_IP_PAIR:
retval = read_nip(val, buffer);
val = strtok(NULL, ", \t/-");
if (!val)
retval = 0;
if (retval)
retval = read_nip(val, buffer + 4);
break;
case OPTION_STRING:
#if ENABLE_FEATURE_UDHCP_RFC3397
case OPTION_STR1035:
#endif
length = strnlen(val, 254);
if (length > 0) {
opt = val;
retval = 1;
}
break;
case OPTION_BOOLEAN:
retval = read_yn(val, buffer);
break;
case OPTION_U8:
buffer[0] = strtoul(val, &endptr, 0);
retval = (endptr[0] == '\0');
break;
/* htonX are macros in older libc's, using temp var
* in code below for safety */
/* TODO: use bb_strtoX? */
case OPTION_U16: {
unsigned long tmp = strtoul(val, &endptr, 0);
*result_u16 = htons(tmp);
retval = (endptr[0] == '\0' /*&& tmp < 0x10000*/);
break;
}
case OPTION_S16: {
long tmp = strtol(val, &endptr, 0);
*result_u16 = htons(tmp);
retval = (endptr[0] == '\0');
break;
}
case OPTION_U32: {
unsigned long tmp = strtoul(val, &endptr, 0);
*result_u32 = htonl(tmp);
retval = (endptr[0] == '\0');
break;
}
case OPTION_S32: {
long tmp = strtol(val, &endptr, 0);
*result_u32 = htonl(tmp);
retval = (endptr[0] == '\0');
break;
}
default:
break;
}
if (retval)
attach_option(opt_list, option, opt, length);
} while (retval && option->flags & OPTION_LIST);
return retval;
}
static int FAST_FUNC read_staticlease(const char *const_line, void *arg)
{
char *line;
char *mac_string;
char *ip_string;
struct ether_addr mac_bytes;
uint32_t ip;
/* Read mac */
line = (char *) const_line;
mac_string = strtok_r(line, " \t", &line);
read_mac(mac_string, &mac_bytes);
/* Read ip */
ip_string = strtok_r(NULL, " \t", &line);
read_nip(ip_string, &ip);
add_static_lease(arg, (uint8_t*) &mac_bytes, ip);
log_static_leases(arg);
return 1;
}
struct config_keyword {
const char *keyword;
int (*handler)(const char *line, void *var) FAST_FUNC;
void *var;
const char *def;
};
static const struct config_keyword keywords[] = {
/* keyword handler variable address default */
{"start", read_nip, &(server_config.start_ip), "192.168.0.20"},
{"end", read_nip, &(server_config.end_ip), "192.168.0.254"},
{"interface", read_str, &(server_config.interface), "eth0"},
/* Avoid "max_leases value not sane" warning by setting default
* to default_end_ip - default_start_ip + 1: */
{"max_leases", read_u32, &(server_config.max_leases), "235"},
{"auto_time", read_u32, &(server_config.auto_time), "7200"},
{"decline_time", read_u32, &(server_config.decline_time), "3600"},
{"conflict_time",read_u32, &(server_config.conflict_time),"3600"},
{"offer_time", read_u32, &(server_config.offer_time), "60"},
{"min_lease", read_u32, &(server_config.min_lease_sec),"60"},
{"lease_file", read_str, &(server_config.lease_file), LEASES_FILE},
{"pidfile", read_str, &(server_config.pidfile), "/var/run/udhcpd.pid"},
{"siaddr", read_nip, &(server_config.siaddr_nip), "0.0.0.0"},
/* keywords with no defaults must be last! */
{"option", read_opt, &(server_config.options), ""},
{"opt", read_opt, &(server_config.options), ""},
{"notify_file", read_str, &(server_config.notify_file), ""},
{"sname", read_str, &(server_config.sname), ""},
{"boot_file", read_str, &(server_config.boot_file), ""},
{"static_lease", read_staticlease, &(server_config.static_leases), ""},
};
enum { KWS_WITH_DEFAULTS = ARRAY_SIZE(keywords) - 6 };
void FAST_FUNC read_config(const char *file)
{
parser_t *parser;
const struct config_keyword *k;
unsigned i;
char *token[2];
for (i = 0; i < KWS_WITH_DEFAULTS; i++)
keywords[i].handler(keywords[i].def, keywords[i].var);
parser = config_open(file);
while (config_read(parser, token, 2, 2, "# \t", PARSE_NORMAL)) {
for (k = keywords, i = 0; i < ARRAY_SIZE(keywords); k++, i++) {
if (!strcasecmp(token[0], k->keyword)) {
if (!k->handler(token[1], k->var)) {
bb_error_msg("can't parse line %u in %s",
parser->lineno, file);
/* reset back to the default value */
k->handler(k->def, k->var);
}
break;
}
}
}
config_close(parser);
server_config.start_ip = ntohl(server_config.start_ip);
server_config.end_ip = ntohl(server_config.end_ip);
}
void FAST_FUNC write_leases(void)
{
int fd;
unsigned i;
leasetime_t curr;
int64_t written_at;
fd = open_or_warn(server_config.lease_file, O_WRONLY|O_CREAT|O_TRUNC);
if (fd < 0)
return;
curr = written_at = time(NULL);
written_at = hton64(written_at);
full_write(fd, &written_at, sizeof(written_at));
for (i = 0; i < server_config.max_leases; i++) {
leasetime_t tmp_time;
if (g_leases[i].lease_nip == 0)
continue;
/* Screw with the time in the struct, for easier writing */
tmp_time = g_leases[i].expires;
g_leases[i].expires -= curr;
if ((signed_leasetime_t) g_leases[i].expires < 0)
g_leases[i].expires = 0;
g_leases[i].expires = htonl(g_leases[i].expires);
/* No error check. If the file gets truncated,
* we lose some leases on restart. Oh well. */
full_write(fd, &g_leases[i], sizeof(g_leases[i]));
/* Then restore it when done */
g_leases[i].expires = tmp_time;
}
close(fd);
if (server_config.notify_file) {
// TODO: vfork-based child creation
char *cmd = xasprintf("%s %s", server_config.notify_file, server_config.lease_file);
system(cmd);
free(cmd);
}
}
void FAST_FUNC read_leases(const char *file)
{
struct dyn_lease lease;
int64_t written_at, time_passed;
int fd;
#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
unsigned i = 0;
#endif
fd = open_or_warn(file, O_RDONLY);
if (fd < 0)
return;
if (full_read(fd, &written_at, sizeof(written_at)) != sizeof(written_at))
goto ret;
written_at = ntoh64(written_at);
time_passed = time(NULL) - written_at;
/* Strange written_at, or lease file from old version of udhcpd
* which had no "written_at" field? */
if ((uint64_t)time_passed > 12 * 60 * 60)
goto ret;
while (full_read(fd, &lease, sizeof(lease)) == sizeof(lease)) {
//FIXME: what if it matches some static lease?
uint32_t y = ntohl(lease.lease_nip);
if (y >= server_config.start_ip && y <= server_config.end_ip) {
signed_leasetime_t expires = ntohl(lease.expires) - (signed_leasetime_t)time_passed;
if (expires <= 0)
continue;
/* NB: add_lease takes "relative time", IOW,
* lease duration, not lease deadline. */
if (add_lease(lease.lease_mac, lease.lease_nip,
expires,
lease.hostname, sizeof(lease.hostname)
) == 0
) {
bb_error_msg("too many leases while loading %s", file);
break;
}
#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
i++;
#endif
}
}
log1("Read %d leases", i);
ret:
close(fd);
}