sd-dhcp-lease.c revision bab47929613f9e930dd241a01483b37d14b59c69
/***
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 "unaligned.h"
#include "in-addr-util.h"
#include "dhcp-protocol.h"
#include "dhcp-internal.h"
#include "dhcp-lease-internal.h"
#include "sd-dhcp-lease.h"
#include "sd-dhcp-client.h"
#include "network-internal.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_lifetime(sd_dhcp_lease *lease, uint32_t *lifetime) {
assert_return(lease, -EINVAL);
assert_return(lease, -EINVAL);
*lifetime = lease->lifetime;
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, const struct in_addr **addr) {
assert_return(lease, -EINVAL);
assert_return(addr, -EINVAL);
if (lease->dns_size) {
*addr = lease->dns;
return lease->dns_size;
} else
return -ENOENT;
return 0;
}
int sd_dhcp_lease_get_ntp(sd_dhcp_lease *lease, const struct in_addr **addr) {
assert_return(lease, -EINVAL);
assert_return(addr, -EINVAL);
if (lease->ntp_size) {
*addr = lease->ntp;
return lease->ntp_size;
} 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);
if (lease->router != INADDR_ANY)
addr->s_addr = lease->router;
else
return -ENOENT;
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;
}
int sd_dhcp_lease_get_routes(sd_dhcp_lease *lease, struct sd_dhcp_route **routes) {
assert_return(lease, -EINVAL);
assert_return(routes, -EINVAL);
if (lease->static_route_size) {
*routes = lease->static_route;
return lease->static_route_size;
} else
return -ENOENT;
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->ntp);
free(lease->static_route);
free(lease);
}
return NULL;
}
static void lease_parse_u32(const uint8_t *option, size_t len, uint32_t *ret, uint32_t min) {
assert(option);
assert(ret);
if (len == 4) {
*ret = unaligned_read_be32((be32_t*) option);
if (*ret < min)
*ret = min;
}
}
static void lease_parse_s32(const uint8_t *option, size_t len, int32_t *ret) {
lease_parse_u32(option, len, (uint32_t *)ret, 0);
}
static void lease_parse_u16(const uint8_t *option, size_t len, uint16_t *ret, uint16_t min) {
assert(option);
assert(ret);
if (len == 2) {
*ret = unaligned_read_be16((be16_t*) option);
if (*ret < min)
*ret = min;
}
}
static void lease_parse_be32(const uint8_t *option, size_t len, be32_t *ret) {
assert(option);
assert(ret);
if (len == 4)
memcpy(ret, option, 4);
}
static void lease_parse_bool(const uint8_t *option, size_t len, bool *ret) {
assert(option);
assert(ret);
if (len == 1)
*ret = !!(*option);
}
static void lease_parse_u8(const uint8_t *option, size_t len, uint8_t *ret, uint8_t min) {
assert(option);
assert(ret);
if (len == 1) {
*ret = *option;
if (*ret < min)
*ret = min;
}
}
static int lease_parse_string(const uint8_t *option, size_t len, char **ret) {
assert(option);
assert(ret);
if (len >= 1) {
char *string;
string = strndup((const char *)option, len);
if (!string)
return -errno;
free(*ret);
*ret = string;
}
return 0;
}
static int lease_parse_in_addrs_aux(const uint8_t *option, size_t len, struct in_addr **ret, size_t *ret_size, size_t mult) {
assert(option);
assert(ret);
assert(ret_size);
if (len && !(len % (4 * mult))) {
size_t size;
struct in_addr *addresses;
size = len / 4;
addresses = newdup(struct in_addr, option, size);
if (!addresses)
return -ENOMEM;
free(*ret);
*ret = addresses;
*ret_size = size;
}
return 0;
}
static int lease_parse_in_addrs(const uint8_t *option, size_t len, struct in_addr **ret, size_t *ret_size) {
return lease_parse_in_addrs_aux(option, len, ret, ret_size, 1);
}
static int lease_parse_in_addrs_pairs(const uint8_t *option, size_t len, struct in_addr **ret, size_t *ret_size) {
return lease_parse_in_addrs_aux(option, len, ret, ret_size, 2);
}
static int class_prefixlen(uint8_t msb_octet, uint8_t *ret) {
if (msb_octet < 128)
/* Class A */
*ret = 8;
else if (msb_octet < 192)
/* Class B */
*ret = 16;
else if (msb_octet < 224)
/* Class C */
*ret = 24;
else
/* Class D or E -- no subnet mask */
return -ERANGE;
return 0;
}
static int lease_parse_routes(const uint8_t *option, size_t len, struct sd_dhcp_route **routes,
size_t *routes_size, size_t *routes_allocated) {
struct in_addr addr;
assert(option);
assert(routes);
assert(routes_size);
assert(routes_allocated);
if (!len)
return 0;
if (len % 8 != 0)
return -EINVAL;
if (!GREEDY_REALLOC(*routes, *routes_allocated, *routes_size + (len / 8)))
return -ENOMEM;
while (len >= 8) {
struct sd_dhcp_route *route = *routes + *routes_size;
if (class_prefixlen(*option, &route->dst_prefixlen) < 0) {
log_error("Failed to determine destination prefix length from class based IP, ignoring");
continue;
}
lease_parse_be32(option, 4, &addr.s_addr);
route->dst_addr = inet_makeaddr(inet_netof(addr), 0);
option += 4;
lease_parse_be32(option, 4, &route->gw_addr.s_addr);
option += 4;
len -= 8;
(*routes_size)++;
}
return 0;
}
/* parses RFC3442 Classless Static Route Option */
static int lease_parse_classless_routes(const uint8_t *option, size_t len, struct sd_dhcp_route **routes,
size_t *routes_size, size_t *routes_allocated) {
assert(option);
assert(routes);
assert(routes_size);
assert(routes_allocated);
/* option format: (subnet-mask-width significant-subnet-octets gateway-ip)* */
while (len > 0) {
uint8_t dst_octets;
struct sd_dhcp_route *route;
if (!GREEDY_REALLOC(*routes, *routes_allocated, *routes_size + 1))
return -ENOMEM;
route = *routes + *routes_size;
dst_octets = (*option == 0 ? 0 : ((*option - 1) / 8) + 1);
route->dst_prefixlen = *option;
option++;
len--;
/* can't have more than 4 octets in IPv4 */
if (dst_octets > 4 || len < dst_octets)
return -EINVAL;
route->dst_addr.s_addr = 0;
memcpy(&route->dst_addr.s_addr, option, dst_octets);
option += dst_octets;
len -= dst_octets;
if (len < 4)
return -EINVAL;
lease_parse_be32(option, 4, &route->gw_addr.s_addr);
option += 4;
len -= 4;
(*routes_size)++;
}
return 0;
}
int dhcp_lease_parse_options(uint8_t code, uint8_t len, const uint8_t *option,
void *user_data) {
sd_dhcp_lease *lease = user_data;
int r;
assert(lease);
switch(code) {
case DHCP_OPTION_TIME_OFFSET:
lease_parse_s32(option, len, &lease->time_offset);
break;
case DHCP_OPTION_INTERFACE_MTU_AGING_TIMEOUT:
lease_parse_u32(option, len, &lease->mtu_aging_timeout, 0);
break;
case DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
lease_parse_u32(option, len, &lease->lifetime, 1);
break;
case DHCP_OPTION_SERVER_IDENTIFIER:
lease_parse_be32(option, len, &lease->server_address);
break;
case DHCP_OPTION_SUBNET_MASK:
lease_parse_be32(option, len, &lease->subnet_mask);
break;
case DHCP_OPTION_BROADCAST:
lease_parse_be32(option, len, &lease->broadcast);
break;
case DHCP_OPTION_ROUTER:
lease_parse_be32(option, len, &lease->router);
break;
case DHCP_OPTION_DOMAIN_NAME_SERVER:
r = lease_parse_in_addrs(option, len, &lease->dns, &lease->dns_size);
if (r < 0)
return r;
break;
case DHCP_OPTION_NTP_SERVER:
r = lease_parse_in_addrs(option, len, &lease->ntp, &lease->ntp_size);
if (r < 0)
return r;
break;
case DHCP_OPTION_POLICY_FILTER:
r = lease_parse_in_addrs_pairs(option, len, &lease->policy_filter, &lease->policy_filter_size);
if (r < 0)
return r;
break;
case DHCP_OPTION_STATIC_ROUTE:
r = lease_parse_routes(option, len, &lease->static_route, &lease->static_route_size,
&lease->static_route_allocated);
if (r < 0)
return r;
break;
case DHCP_OPTION_INTERFACE_MTU:
lease_parse_u16(option, len, &lease->mtu, 68);
break;
case DHCP_OPTION_INTERFACE_MDR:
lease_parse_u16(option, len, &lease->mdr, 576);
break;
case DHCP_OPTION_INTERFACE_TTL:
lease_parse_u8(option, len, &lease->ttl, 1);
break;
case DHCP_OPTION_BOOT_FILE_SIZE:
lease_parse_u16(option, len, &lease->boot_file_size, 0);
break;
case DHCP_OPTION_DOMAIN_NAME:
{
_cleanup_free_ char *domainname = NULL;
r = lease_parse_string(option, len, &domainname);
if (r < 0)
return r;
if (!hostname_is_valid(domainname) || is_localhost(domainname))
break;
free(lease->domainname);
lease->domainname = domainname;
domainname = NULL;
break;
}
case DHCP_OPTION_HOST_NAME:
{
_cleanup_free_ char *hostname = NULL;
r = lease_parse_string(option, len, &hostname);
if (r < 0)
return r;
if (!hostname_is_valid(hostname) || is_localhost(hostname))
break;
free(lease->hostname);
lease->hostname = hostname;
hostname = NULL;
break;
}
case DHCP_OPTION_ROOT_PATH:
r = lease_parse_string(option, len, &lease->root_path);
if (r < 0)
return r;
break;
case DHCP_OPTION_RENEWAL_T1_TIME:
lease_parse_u32(option, len, &lease->t1, 1);
break;
case DHCP_OPTION_REBINDING_T2_TIME:
lease_parse_u32(option, len, &lease->t2, 1);
break;
case DHCP_OPTION_ENABLE_IP_FORWARDING:
lease_parse_bool(option, len, &lease->ip_forward);
break;
case DHCP_OPTION_ENABLE_IP_FORWARDING_NL:
lease_parse_bool(option, len, &lease->ip_forward_non_local);
break;
case DHCP_OPTION_CLASSLESS_STATIC_ROUTE:
r = lease_parse_classless_routes(option, len, &lease->static_route, &lease->static_route_size,
&lease->static_route_allocated);
if (r < 0)
return r;
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->router = INADDR_ANY;
lease->n_ref = REFCNT_INIT;
*ret = lease;
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;
const struct in_addr *addresses;
const char *string;
uint16_t mtu;
struct sd_dhcp_route *routes;
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_netmask(lease, &address);
if (r < 0)
goto finish;
fprintf(f, "NETMASK=%s\n", inet_ntoa(address));
r = sd_dhcp_lease_get_router(lease, &address);
if (r >= 0)
fprintf(f, "ROUTER=%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);
fputs("DNS=", f);
r = sd_dhcp_lease_get_dns(lease, &addresses);
if (r >= 0)
serialize_in_addrs(f, addresses, r);
fputs("\n", f);
fputs("NTP=", f);
r = sd_dhcp_lease_get_ntp(lease, &addresses);
if (r >= 0)
serialize_in_addrs(f, addresses, r);
fputs("\n", f);
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 = sd_dhcp_lease_get_routes(lease, &routes);
if (r >= 0)
serialize_dhcp_routes(f, "ROUTES", routes, r);
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, *routes = 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,
"ROUTES", &routes,
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;
if (router) {
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_in_addrs(&lease->dns, dns);
if (r < 0)
return r;
lease->dns_size = r;
}
if (ntp) {
r = deserialize_in_addrs(&lease->ntp, ntp);
if (r < 0)
return r;
lease->ntp_size = r;
}
if (mtu) {
uint16_t u;
if (sscanf(mtu, "%" SCNu16, &u) > 0)
lease->mtu = u;
}
if (routes) {
r = deserialize_dhcp_routes(&lease->static_route, &lease->static_route_size,
&lease->static_route_allocated, routes);
if (r < 0)
return r;
}
*ret = lease;
lease = NULL;
return 0;
}
int dhcp_lease_set_default_subnet_mask(sd_dhcp_lease *lease) {
struct in_addr address;
struct in_addr mask;
int r;
assert(lease);
address.s_addr = lease->address;
/* fall back to the default subnet masks based on address class */
r = in_addr_default_subnet_mask(&address, &mask);
if (r < 0)
return r;
lease->subnet_mask = mask.s_addr;
return 0;
}