sd-dhcp-lease.c revision 109731eb250705e055b98b844d7c0dfb74bcf728
/***
This file is part of systemd.
Copyright (C) 2013 Intel Corporation. All rights reserved.
Copyright (C) 2014 Tom Gundersen
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <net/ethernet.h>
#include <arpa/inet.h>
#include <sys/param.h>
#include "util.h"
#include "list.h"
#include "mkdir.h"
#include "fileio.h"
#include "dhcp-protocol.h"
#include "dhcp-internal.h"
#include "dhcp-lease-internal.h"
#include "sd-dhcp-lease.h"
#include "sd-dhcp-client.h"
int sd_dhcp_lease_get_address(sd_dhcp_lease *lease, struct in_addr *addr) {
assert_return(lease, -EINVAL);
assert_return(addr, -EINVAL);
addr->s_addr = lease->address;
return 0;
}
int sd_dhcp_lease_get_mtu(sd_dhcp_lease *lease, uint16_t *mtu) {
assert_return(lease, -EINVAL);
assert_return(mtu, -EINVAL);
if (lease->mtu)
*mtu = lease->mtu;
else
return -ENOENT;
return 0;
}
int sd_dhcp_lease_get_dns(sd_dhcp_lease *lease, struct in_addr **addr, size_t *addr_size) {
assert_return(lease, -EINVAL);
assert_return(addr, -EINVAL);
assert_return(addr_size, -EINVAL);
if (lease->dns_size) {
*addr_size = lease->dns_size;
*addr = lease->dns;
} else
return -ENOENT;
return 0;
}
int sd_dhcp_lease_get_ntp(sd_dhcp_lease *lease, struct in_addr **addr, size_t *addr_size) {
assert_return(lease, -EINVAL);
assert_return(addr, -EINVAL);
assert_return(addr_size, -EINVAL);
if (lease->ntp_size) {
*addr_size = lease->ntp_size;
*addr = lease->ntp;
} else
return -ENOENT;
return 0;
}
int sd_dhcp_lease_get_domainname(sd_dhcp_lease *lease, const char **domainname) {
assert_return(lease, -EINVAL);
assert_return(domainname, -EINVAL);
if (lease->domainname)
*domainname = lease->domainname;
else
return -ENOENT;
return 0;
}
int sd_dhcp_lease_get_hostname(sd_dhcp_lease *lease, const char **hostname) {
assert_return(lease, -EINVAL);
assert_return(hostname, -EINVAL);
if (lease->hostname)
*hostname = lease->hostname;
else
return -ENOENT;
return 0;
}
int sd_dhcp_lease_get_root_path(sd_dhcp_lease *lease, const char **root_path) {
assert_return(lease, -EINVAL);
assert_return(root_path, -EINVAL);
if (lease->root_path)
*root_path = lease->root_path;
else
return -ENOENT;
return 0;
}
int sd_dhcp_lease_get_router(sd_dhcp_lease *lease, struct in_addr *addr) {
assert_return(lease, -EINVAL);
assert_return(addr, -EINVAL);
addr->s_addr = lease->router;
return 0;
}
int sd_dhcp_lease_get_netmask(sd_dhcp_lease *lease, struct in_addr *addr) {
assert_return(lease, -EINVAL);
assert_return(addr, -EINVAL);
addr->s_addr = lease->subnet_mask;
return 0;
}
int sd_dhcp_lease_get_server_identifier(sd_dhcp_lease *lease, struct in_addr *addr) {
assert_return(lease, -EINVAL);
assert_return(addr, -EINVAL);
addr->s_addr = lease->server_address;
return 0;
}
int sd_dhcp_lease_get_next_server(sd_dhcp_lease *lease, struct in_addr *addr) {
assert_return(lease, -EINVAL);
assert_return(addr, -EINVAL);
addr->s_addr = lease->next_server;
return 0;
}
sd_dhcp_lease *sd_dhcp_lease_ref(sd_dhcp_lease *lease) {
if (lease)
assert_se(REFCNT_INC(lease->n_ref) >= 2);
return lease;
}
sd_dhcp_lease *sd_dhcp_lease_unref(sd_dhcp_lease *lease) {
if (lease && REFCNT_DEC(lease->n_ref) <= 0) {
free(lease->hostname);
free(lease->domainname);
free(lease->dns);
free(lease);
}
return NULL;
}
int dhcp_lease_parse_options(uint8_t code, uint8_t len, const uint8_t *option,
void *user_data) {
sd_dhcp_lease *lease = user_data;
be32_t val;
switch(code) {
case DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
if (len == 4) {
memcpy(&val, option, 4);
lease->lifetime = be32toh(val);
}
break;
case DHCP_OPTION_SERVER_IDENTIFIER:
if (len >= 4)
memcpy(&lease->server_address, option, 4);
break;
case DHCP_OPTION_SUBNET_MASK:
if (len >= 4)
memcpy(&lease->subnet_mask, option, 4);
break;
case DHCP_OPTION_ROUTER:
if (len >= 4)
memcpy(&lease->router, option, 4);
break;
case DHCP_OPTION_DOMAIN_NAME_SERVER:
if (len && !(len % 4)) {
lease->dns_size = len / 4;
free(lease->dns);
lease->dns = newdup(struct in_addr, option, lease->dns_size);
if (!lease->dns)
return -ENOMEM;
}
break;
case DHCP_OPTION_NTP_SERVER:
if (len && !(len % 4)) {
lease->ntp_size = len / 4;
free(lease->ntp);
lease->ntp = newdup(struct in_addr, option, lease->ntp_size);
if (!lease->ntp)
return -ENOMEM;
}
break;
case DHCP_OPTION_INTERFACE_MTU:
if (len >= 2) {
be16_t mtu;
memcpy(&mtu, option, 2);
lease->mtu = be16toh(mtu);
if (lease->mtu < 68)
lease->mtu = 0;
}
break;
case DHCP_OPTION_DOMAIN_NAME:
if (len >= 1) {
free(lease->domainname);
lease->domainname = strndup((const char *)option, len);
}
break;
case DHCP_OPTION_HOST_NAME:
if (len >= 1) {
free(lease->hostname);
lease->hostname = strndup((const char *)option, len);
}
break;
case DHCP_OPTION_ROOT_PATH:
if (len >= 1) {
free(lease->root_path);
lease->root_path = strndup((const char *)option, len);
}
break;
case DHCP_OPTION_RENEWAL_T1_TIME:
if (len == 4) {
memcpy(&val, option, 4);
lease->t1 = be32toh(val);
}
break;
case DHCP_OPTION_REBINDING_T2_TIME:
if (len == 4) {
memcpy(&val, option, 4);
lease->t2 = be32toh(val);
}
break;
}
return 0;
}
int dhcp_lease_new(sd_dhcp_lease **ret) {
sd_dhcp_lease *lease;
lease = new0(sd_dhcp_lease, 1);
if (!lease)
return -ENOMEM;
lease->n_ref = REFCNT_INIT;
*ret = lease;
return 0;
}
static void serialize_addresses(FILE *f, const char *key, struct in_addr *addresses, size_t size) {
unsigned i;
assert(key);
assert(addresses);
assert(size);
fputs("DNS=", f);
for (i = 0; i < size; i++)
fprintf(f, "%s%s", inet_ntoa(addresses[i]),
(i < (size - 1)) ? " ": "");
fputs("\n", f);
}
static int deserialize_addresses(struct in_addr **addresses, size_t *size, const char *string) {
char *word, *state;
size_t len;
FOREACH_WORD(word, len, string, state) {
struct in_addr *new_addresses;
int r;
new_addresses = realloc(*addresses, (*size + 1) * sizeof(struct in_addr));
if (!new_addresses)
return -ENOMEM;
r = inet_aton(word, &(new_addresses[*size]));
if (r < 0)
continue;
*addresses = new_addresses;
(*size)++;
}
return 0;
}
int dhcp_lease_save(sd_dhcp_lease *lease, const char *lease_file) {
_cleanup_free_ char *temp_path = NULL;
_cleanup_fclose_ FILE *f = NULL;
struct in_addr address;
struct in_addr *addresses;
size_t addresses_size;
const char *string;
uint16_t mtu;
int r;
assert(lease);
assert(lease_file);
r = fopen_temporary(lease_file, &f, &temp_path);
if (r < 0)
goto finish;
fchmod(fileno(f), 0644);
r = sd_dhcp_lease_get_address(lease, &address);
if (r < 0)
goto finish;
fprintf(f,
"# This is private data. Do not parse.\n"
"ADDRESS=%s\n", inet_ntoa(address));
r = sd_dhcp_lease_get_router(lease, &address);
if (r < 0)
goto finish;
fprintf(f, "ROUTER=%s\n", inet_ntoa(address));
r = sd_dhcp_lease_get_netmask(lease, &address);
if (r < 0)
goto finish;
fprintf(f, "NETMASK=%s\n", inet_ntoa(address));
r = sd_dhcp_lease_get_server_identifier(lease, &address);
if (r >= 0)
fprintf(f, "SERVER_ADDRESS=%s\n",
inet_ntoa(address));
r = sd_dhcp_lease_get_next_server(lease, &address);
if (r >= 0)
fprintf(f, "NEXT_SERVER=%s\n", inet_ntoa(address));
r = sd_dhcp_lease_get_mtu(lease, &mtu);
if (r >= 0)
fprintf(f, "MTU=%" PRIu16 "\n", mtu);
r = sd_dhcp_lease_get_dns(lease, &addresses, &addresses_size);
if (r >= 0)
serialize_addresses(f, "DNS", addresses, addresses_size);
r = sd_dhcp_lease_get_ntp(lease, &addresses, &addresses_size);
if (r >= 0)
serialize_addresses(f, "NTP", addresses, addresses_size);
r = sd_dhcp_lease_get_domainname(lease, &string);
if (r >= 0)
fprintf(f, "DOMAINNAME=%s\n", string);
r = sd_dhcp_lease_get_hostname(lease, &string);
if (r >= 0)
fprintf(f, "HOSTNAME=%s\n", string);
r = sd_dhcp_lease_get_root_path(lease, &string);
if (r >= 0)
fprintf(f, "ROOT_PATH=%s\n", string);
r = 0;
fflush(f);
if (ferror(f) || rename(temp_path, lease_file) < 0) {
r = -errno;
unlink(lease_file);
unlink(temp_path);
}
finish:
if (r < 0)
log_error("Failed to save lease data %s: %s", lease_file, strerror(-r));
return r;
}
int dhcp_lease_load(const char *lease_file, sd_dhcp_lease **ret) {
_cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
_cleanup_free_ char *address = NULL, *router = NULL, *netmask = NULL,
*server_address = NULL, *next_server = NULL,
*dns = NULL, *ntp = NULL, *mtu = NULL;
struct in_addr addr;
int r;
assert(lease_file);
assert(ret);
r = dhcp_lease_new(&lease);
if (r < 0)
return r;
r = parse_env_file(lease_file, NEWLINE,
"ADDRESS", &address,
"ROUTER", &router,
"NETMASK", &netmask,
"SERVER_IDENTIFIER", &server_address,
"NEXT_SERVER", &next_server,
"DNS", &dns,
"NTP", &ntp,
"MTU", &mtu,
"DOMAINNAME", &lease->domainname,
"HOSTNAME", &lease->hostname,
"ROOT_PATH", &lease->root_path,
NULL);
if (r < 0) {
if (r == -ENOENT)
return 0;
log_error("Failed to read %s: %s", lease_file, strerror(-r));
return r;
}
r = inet_pton(AF_INET, address, &addr);
if (r < 0)
return r;
lease->address = addr.s_addr;
r = inet_pton(AF_INET, router, &addr);
if (r < 0)
return r;
lease->router = addr.s_addr;
r = inet_pton(AF_INET, netmask, &addr);
if (r < 0)
return r;
lease->subnet_mask = addr.s_addr;
if (server_address) {
r = inet_pton(AF_INET, server_address, &addr);
if (r < 0)
return r;
lease->server_address = addr.s_addr;
}
if (next_server) {
r = inet_pton(AF_INET, next_server, &addr);
if (r < 0)
return r;
lease->next_server = addr.s_addr;
}
if (dns) {
r = deserialize_addresses(&lease->dns, &lease->dns_size, dns);
if (r < 0)
return r;
}
if (ntp) {
r = deserialize_addresses(&lease->ntp, &lease->ntp_size, dns);
if (r < 0)
return r;
}
if (mtu) {
uint16_t u;
if (sscanf(mtu, "%" SCNu16, &u) > 0)
lease->mtu = u;
}
*ret = lease;
lease = NULL;
return 0;
}
int dhcp_lease_set_default_subnet_mask(sd_dhcp_lease *lease) {
uint32_t address;
assert(lease);
assert(lease->address != INADDR_ANY);
address = be32toh(lease->address);
/* fall back to the default subnet masks based on address class */
if ((address >> 31) == 0x0)
/* class A, leading bits: 0 */
lease->subnet_mask = htobe32(0xff000000);
else if ((address >> 30) == 0x2)
/* class B, leading bits 10 */
lease->subnet_mask = htobe32(0xffff0000);
else if ((address >> 29) == 0x6)
/* class C, leading bits 110 */
lease->subnet_mask = htobe32(0xffffff00);
else
/* class D or E, no default mask. give up */
return -ERANGE;
return 0;
}