blob: f3f702819c4d198fb17626c154ad85fe04f5e38d [file] [log] [blame]
/** @file
* @brief DHCPv4 client related functions
*/
/*
* Copyright (c) 2017 ARM Ltd.
* Copyright (c) 2016 Intel Corporation
* Copyright (c) 2018 Vincent van der Locht
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <logging/log.h>
LOG_MODULE_REGISTER(net_dhcpv4, CONFIG_NET_DHCPV4_LOG_LEVEL);
#include <errno.h>
#include <inttypes.h>
#include <random/rand32.h>
#include <net/net_core.h>
#include <net/net_pkt.h>
#include <net/net_if.h>
#include <net/net_mgmt.h>
#include "net_private.h"
#include <net/udp.h>
#include "udp_internal.h"
#include <net/dhcpv4.h>
#include <net/dns_resolve.h>
#include "dhcpv4.h"
#include "ipv4.h"
#define PKT_WAIT_TIME K_SECONDS(1)
static K_MUTEX_DEFINE(lock);
static sys_slist_t dhcpv4_ifaces;
static struct k_work_delayable timeout_work;
static struct net_mgmt_event_callback mgmt4_cb;
/* RFC 1497 [17] */
static const uint8_t magic_cookie[4] = { 0x63, 0x82, 0x53, 0x63 };
static const char *dhcpv4_msg_type_name(enum dhcpv4_msg_type msg_type)
__attribute__((unused));
static const char *dhcpv4_msg_type_name(enum dhcpv4_msg_type msg_type)
{
static const char * const name[] = {
"discover",
"offer",
"request",
"decline",
"ack",
"nak",
"release",
"inform"
};
__ASSERT_NO_MSG(msg_type >= 1 && msg_type <= sizeof(name));
return name[msg_type - 1];
}
/* Add magic cookie to DCHPv4 messages */
static inline bool dhcpv4_add_cookie(struct net_pkt *pkt)
{
if (net_pkt_write(pkt, (void *)magic_cookie,
ARRAY_SIZE(magic_cookie))) {
return false;
}
return true;
}
/* Add a an option with the form OPTION LENGTH VALUE. */
static bool dhcpv4_add_option_length_value(struct net_pkt *pkt, uint8_t option,
uint8_t size, const void *value)
{
if (net_pkt_write_u8(pkt, option) ||
net_pkt_write_u8(pkt, size) ||
net_pkt_write(pkt, value, size)) {
return false;
}
return true;
}
/* Add DHCPv4 message type */
static bool dhcpv4_add_msg_type(struct net_pkt *pkt, uint8_t type)
{
return dhcpv4_add_option_length_value(pkt, DHCPV4_OPTIONS_MSG_TYPE,
1, &type);
}
/* Add DHCPv4 minimum required options for server to reply.
* Can be added more if needed.
*/
static bool dhcpv4_add_req_options(struct net_pkt *pkt)
{
static uint8_t data[3] = { DHCPV4_OPTIONS_SUBNET_MASK,
DHCPV4_OPTIONS_ROUTER,
DHCPV4_OPTIONS_DNS_SERVER };
return dhcpv4_add_option_length_value(pkt, DHCPV4_OPTIONS_REQ_LIST,
ARRAY_SIZE(data), data);
}
static bool dhcpv4_add_server_id(struct net_pkt *pkt,
const struct in_addr *addr)
{
return dhcpv4_add_option_length_value(pkt, DHCPV4_OPTIONS_SERVER_ID,
4, addr->s4_addr);
}
static bool dhcpv4_add_req_ipaddr(struct net_pkt *pkt,
const struct in_addr *addr)
{
return dhcpv4_add_option_length_value(pkt, DHCPV4_OPTIONS_REQ_IPADDR,
4, addr->s4_addr);
}
#if defined(CONFIG_NET_HOSTNAME_ENABLE)
static bool dhcpv4_add_hostname(struct net_pkt *pkt,
const char *hostname, const size_t size)
{
return dhcpv4_add_option_length_value(pkt, DHCPV4_OPTIONS_HOST_NAME,
size, hostname);
}
#endif
/* Add DHCPv4 Options end, rest of the message can be padded wit zeros */
static inline bool dhcpv4_add_end(struct net_pkt *pkt)
{
if (net_pkt_write_u8(pkt, DHCPV4_OPTIONS_END)) {
return false;
}
return true;
}
/* File is empty ATM */
static inline bool dhcpv4_add_file(struct net_pkt *pkt)
{
if (net_pkt_memset(pkt, 0, SIZE_OF_FILE)) {
return false;
}
return true;
}
/* SNAME is empty ATM */
static inline bool dhcpv4_add_sname(struct net_pkt *pkt)
{
if (net_pkt_memset(pkt, 0, SIZE_OF_SNAME)) {
return false;
}
return true;
}
/* Create DHCPv4 message and add options as per message type */
static struct net_pkt *dhcpv4_create_message(struct net_if *iface, uint8_t type,
const struct in_addr *ciaddr,
const struct in_addr *src_addr,
const struct in_addr *server_addr,
bool server_id, bool requested_ip)
{
NET_PKT_DATA_ACCESS_DEFINE(dhcp_access, struct dhcp_msg);
const struct in_addr *addr;
size_t size = DHCPV4_MESSAGE_SIZE;
struct net_pkt *pkt;
struct dhcp_msg *msg;
#if defined(CONFIG_NET_HOSTNAME_ENABLE)
const char *hostname = net_hostname_get();
const size_t hostname_size = strlen(hostname);
#endif
if (src_addr == NULL) {
addr = net_ipv4_unspecified_address();
} else {
addr = src_addr;
}
if (server_id) {
size += DHCPV4_OLV_MSG_SERVER_ID;
}
if (requested_ip) {
size += DHCPV4_OLV_MSG_REQ_IPADDR;
}
if (type == DHCPV4_MSG_TYPE_DISCOVER) {
size += DHCPV4_OLV_MSG_REQ_LIST;
}
#if defined(CONFIG_NET_HOSTNAME_ENABLE)
if (hostname_size > 0) {
size += DHCPV4_OLV_MSG_HOST_NAME + hostname_size;
}
#endif
pkt = net_pkt_alloc_with_buffer(iface, size, AF_INET,
IPPROTO_UDP, K_FOREVER);
net_pkt_set_ipv4_ttl(pkt, 0xFF);
if (net_ipv4_create(pkt, addr, server_addr) ||
net_udp_create(pkt, htons(DHCPV4_CLIENT_PORT),
htons(DHCPV4_SERVER_PORT))) {
goto fail;
}
msg = (struct dhcp_msg *)net_pkt_get_data(pkt, &dhcp_access);
(void)memset(msg, 0, sizeof(struct dhcp_msg));
msg->op = DHCPV4_MSG_BOOT_REQUEST;
msg->htype = HARDWARE_ETHERNET_TYPE;
msg->hlen = net_if_get_link_addr(iface)->len;
msg->xid = htonl(iface->config.dhcpv4.xid);
msg->flags = htons(DHCPV4_MSG_BROADCAST);
if (ciaddr) {
/* The ciaddr field was zero'd out above, if we are
* asked to send a ciaddr then fill it in now
* otherwise leave it as all zeros.
*/
memcpy(msg->ciaddr, ciaddr, 4);
}
memcpy(msg->chaddr, net_if_get_link_addr(iface)->addr,
net_if_get_link_addr(iface)->len);
if (net_pkt_set_data(pkt, &dhcp_access)) {
goto fail;
}
if (!dhcpv4_add_sname(pkt) ||
!dhcpv4_add_file(pkt) ||
!dhcpv4_add_cookie(pkt) ||
!dhcpv4_add_msg_type(pkt, type)) {
goto fail;
}
if ((server_id &&
!dhcpv4_add_server_id(pkt, &iface->config.dhcpv4.server_id)) ||
(requested_ip &&
!dhcpv4_add_req_ipaddr(pkt, &iface->config.dhcpv4.requested_ip))) {
goto fail;
}
if (type == DHCPV4_MSG_TYPE_DISCOVER && !dhcpv4_add_req_options(pkt)) {
goto fail;
}
#if defined(CONFIG_NET_HOSTNAME_ENABLE)
if (hostname_size > 0 &&
!dhcpv4_add_hostname(pkt, hostname, hostname_size)) {
goto fail;
}
#endif
if (!dhcpv4_add_end(pkt)) {
goto fail;
}
net_pkt_cursor_init(pkt);
net_ipv4_finalize(pkt, IPPROTO_UDP);
return pkt;
fail:
NET_DBG("Message creation failed");
net_pkt_unref(pkt);
return NULL;
}
/* Must be invoked with lock held. */
static void dhcpv4_immediate_timeout(struct net_if_dhcpv4 *dhcpv4)
{
NET_DBG("force timeout dhcpv4=%p", dhcpv4);
dhcpv4->timer_start = k_uptime_get() - 1;
dhcpv4->request_time = 0U;
k_work_reschedule(&timeout_work, K_NO_WAIT);
}
/* Must be invoked with lock held. */
static void dhcpv4_set_timeout(struct net_if_dhcpv4 *dhcpv4,
uint32_t timeout)
{
NET_DBG("sched timeout dhcvp4=%p timeout=%us", dhcpv4, timeout);
dhcpv4->timer_start = k_uptime_get();
dhcpv4->request_time = timeout;
/* NB: This interface may not be providing the next timeout
* event; also this timeout may replace the current timeout
* event. Delegate scheduling to the timeout manager.
*/
k_work_reschedule(&timeout_work, K_NO_WAIT);
}
/* Must be invoked with lock held */
static uint32_t dhcpv4_update_message_timeout(struct net_if_dhcpv4 *dhcpv4)
{
uint32_t timeout;
timeout = DHCPV4_INITIAL_RETRY_TIMEOUT << dhcpv4->attempts;
/* Max 64 seconds, see RFC 2131 chapter 4.1 */
if (timeout < DHCPV4_INITIAL_RETRY_TIMEOUT || timeout > 64) {
timeout = 64;
}
/* +1/-1 second randomization */
timeout += (sys_rand32_get() % 3U) - 1;
dhcpv4->attempts++;
dhcpv4_set_timeout(dhcpv4, timeout);
return timeout;
}
/* Prepare DHCPv4 Message request and send it to peer.
*
* Returns the number of seconds until the next time-triggered event,
* or UINT32_MAX if the client is in an invalid state.
*/
static uint32_t dhcpv4_send_request(struct net_if *iface)
{
const struct in_addr *server_addr = net_ipv4_broadcast_address();
const struct in_addr *ciaddr = NULL;
const struct in_addr *src_addr = NULL;
bool with_server_id = false;
bool with_requested_ip = false;
struct net_pkt *pkt = NULL;
uint32_t timeout = UINT32_MAX;
iface->config.dhcpv4.xid++;
switch (iface->config.dhcpv4.state) {
case NET_DHCPV4_DISABLED:
case NET_DHCPV4_INIT:
case NET_DHCPV4_SELECTING:
case NET_DHCPV4_BOUND:
/* Not possible */
NET_ASSERT(0, "Invalid state %s",
net_dhcpv4_state_name(iface->config.dhcpv4.state));
goto fail;
break;
case NET_DHCPV4_REQUESTING:
with_server_id = true;
with_requested_ip = true;
break;
case NET_DHCPV4_RENEWING:
/* Since we have an address populate the ciaddr field.
*/
ciaddr = &iface->config.dhcpv4.requested_ip;
/* UNICAST the DHCPREQUEST */
src_addr = ciaddr;
server_addr = &iface->config.dhcpv4.server_id;
/* RFC2131 4.4.5 Client MUST NOT include server
* identifier in the DHCPREQUEST.
*/
break;
case NET_DHCPV4_REBINDING:
/* Since we have an address populate the ciaddr field.
*/
ciaddr = &iface->config.dhcpv4.requested_ip;
src_addr = ciaddr;
break;
}
timeout = dhcpv4_update_message_timeout(&iface->config.dhcpv4);
pkt = dhcpv4_create_message(iface, DHCPV4_MSG_TYPE_REQUEST,
ciaddr, src_addr, server_addr,
with_server_id, with_requested_ip);
if (!pkt) {
goto fail;
}
if (net_send_data(pkt) < 0) {
goto fail;
}
NET_DBG("send request dst=%s xid=0x%x ciaddr=%s%s%s timeout=%us",
log_strdup(net_sprint_ipv4_addr(server_addr)),
iface->config.dhcpv4.xid,
ciaddr ?
log_strdup(net_sprint_ipv4_addr(ciaddr)) : "<unknown>",
with_server_id ? " +server-id" : "",
with_requested_ip ? " +requested-ip" : "",
timeout);
return timeout;
fail:
if (pkt) {
net_pkt_unref(pkt);
}
return timeout;
}
/* Prepare DHCPv4 Discover message and broadcast it */
static uint32_t dhcpv4_send_discover(struct net_if *iface)
{
struct net_pkt *pkt;
uint32_t timeout;
iface->config.dhcpv4.xid++;
pkt = dhcpv4_create_message(iface, DHCPV4_MSG_TYPE_DISCOVER,
NULL, NULL, net_ipv4_broadcast_address(),
false, false);
if (!pkt) {
goto fail;
}
if (net_send_data(pkt) < 0) {
goto fail;
}
timeout = dhcpv4_update_message_timeout(&iface->config.dhcpv4);
NET_DBG("send discover xid=0x%x timeout=%us",
iface->config.dhcpv4.xid, timeout);
return timeout;
fail:
if (pkt) {
net_pkt_unref(pkt);
}
return iface->config.dhcpv4.xid %
(CONFIG_NET_DHCPV4_INITIAL_DELAY_MAX -
DHCPV4_INITIAL_DELAY_MIN) +
DHCPV4_INITIAL_DELAY_MIN;
}
static void dhcpv4_enter_selecting(struct net_if *iface)
{
iface->config.dhcpv4.attempts = 0U;
iface->config.dhcpv4.lease_time = 0U;
iface->config.dhcpv4.renewal_time = 0U;
iface->config.dhcpv4.rebinding_time = 0U;
iface->config.dhcpv4.server_id.s_addr = INADDR_ANY;
iface->config.dhcpv4.requested_ip.s_addr = INADDR_ANY;
iface->config.dhcpv4.state = NET_DHCPV4_SELECTING;
NET_DBG("enter state=%s",
net_dhcpv4_state_name(iface->config.dhcpv4.state));
}
static uint32_t dhcpv4_get_timeleft(int64_t start, uint32_t time, int64_t now)
{
int64_t deadline = start + MSEC_PER_SEC * time;
uint32_t ret = 0U;
/* If we haven't reached the deadline, calculate the
* rounded-up whole seconds until the deadline.
*/
if (deadline > now) {
ret = (uint32_t)ceiling_fraction(deadline - now, MSEC_PER_SEC);
}
return ret;
}
static uint32_t dhcpv4_request_timeleft(struct net_if *iface, int64_t now)
{
uint32_t request_time = iface->config.dhcpv4.request_time;
return dhcpv4_get_timeleft(iface->config.dhcpv4.timer_start,
request_time, now);
}
static uint32_t dhcpv4_renewal_timeleft(struct net_if *iface, int64_t now)
{
uint32_t rem = dhcpv4_get_timeleft(iface->config.dhcpv4.timer_start,
iface->config.dhcpv4.renewal_time,
now);
if (rem == 0U) {
iface->config.dhcpv4.state = NET_DHCPV4_RENEWING;
NET_DBG("enter state=%s",
net_dhcpv4_state_name(iface->config.dhcpv4.state));
iface->config.dhcpv4.attempts = 0U;
}
return rem;
}
static uint32_t dhcpv4_rebinding_timeleft(struct net_if *iface, int64_t now)
{
uint32_t rem = dhcpv4_get_timeleft(iface->config.dhcpv4.timer_start,
iface->config.dhcpv4.rebinding_time,
now);
if (rem == 0U) {
iface->config.dhcpv4.state = NET_DHCPV4_REBINDING;
NET_DBG("enter state=%s",
net_dhcpv4_state_name(iface->config.dhcpv4.state));
iface->config.dhcpv4.attempts = 0U;
}
return rem;
}
static void dhcpv4_enter_requesting(struct net_if *iface)
{
iface->config.dhcpv4.attempts = 0U;
iface->config.dhcpv4.state = NET_DHCPV4_REQUESTING;
NET_DBG("enter state=%s",
net_dhcpv4_state_name(iface->config.dhcpv4.state));
dhcpv4_send_request(iface);
}
/* Must be invoked with lock held */
static void dhcpv4_enter_bound(struct net_if *iface)
{
uint32_t renewal_time;
uint32_t rebinding_time;
renewal_time = iface->config.dhcpv4.renewal_time;
if (!renewal_time) {
/* The default renewal time rfc2131 4.4.5 */
renewal_time = iface->config.dhcpv4.lease_time / 2U;
iface->config.dhcpv4.renewal_time = renewal_time;
}
rebinding_time = iface->config.dhcpv4.rebinding_time;
if (!rebinding_time) {
/* The default rebinding time rfc2131 4.4.5 */
rebinding_time = iface->config.dhcpv4.lease_time * 875U / 1000;
iface->config.dhcpv4.rebinding_time = rebinding_time;
}
iface->config.dhcpv4.state = NET_DHCPV4_BOUND;
NET_DBG("enter state=%s renewal=%us rebinding=%us",
net_dhcpv4_state_name(iface->config.dhcpv4.state),
renewal_time, rebinding_time);
dhcpv4_set_timeout(&iface->config.dhcpv4,
MIN(renewal_time, rebinding_time));
net_mgmt_event_notify_with_info(NET_EVENT_IPV4_DHCP_BOUND, iface,
&iface->config.dhcpv4,
sizeof(iface->config.dhcpv4));
}
static uint32_t dhcpv4_manage_timers(struct net_if *iface, int64_t now)
{
uint32_t timeleft = dhcpv4_request_timeleft(iface, now);
NET_DBG("iface %p dhcpv4=%p state=%s timeleft=%u", iface,
&iface->config.dhcpv4,
net_dhcpv4_state_name(iface->config.dhcpv4.state), timeleft);
if (timeleft != 0U) {
return timeleft;
}
switch (iface->config.dhcpv4.state) {
case NET_DHCPV4_DISABLED:
break;
case NET_DHCPV4_INIT:
dhcpv4_enter_selecting(iface);
__fallthrough;
case NET_DHCPV4_SELECTING:
/* Failed to get OFFER message, send DISCOVER again */
return dhcpv4_send_discover(iface);
case NET_DHCPV4_REQUESTING:
/* Maximum number of renewal attempts failed, so start
* from the beginning.
*/
if (iface->config.dhcpv4.attempts >=
DHCPV4_MAX_NUMBER_OF_ATTEMPTS) {
NET_DBG("too many attempts, restart");
dhcpv4_enter_selecting(iface);
return dhcpv4_send_discover(iface);
}
return dhcpv4_send_request(iface);
case NET_DHCPV4_BOUND:
timeleft = dhcpv4_renewal_timeleft(iface, now);
if (timeleft != 0U) {
timeleft = MIN(timeleft,
dhcpv4_rebinding_timeleft(iface, now));
}
if (timeleft == 0U) {
return dhcpv4_send_request(iface);
}
return timeleft;
case NET_DHCPV4_RENEWING:
case NET_DHCPV4_REBINDING:
if (iface->config.dhcpv4.attempts >=
DHCPV4_MAX_NUMBER_OF_ATTEMPTS) {
NET_DBG("too many attempts, restart");
if (!net_if_ipv4_addr_rm(iface,
&iface->config.dhcpv4.requested_ip)) {
NET_DBG("Failed to remove addr from iface");
}
/* Maximum number of renewal attempts failed, so start
* from the beginning.
*/
dhcpv4_enter_selecting(iface);
return dhcpv4_send_discover(iface);
} else {
return dhcpv4_send_request(iface);
}
}
return UINT32_MAX;
}
static void dhcpv4_timeout(struct k_work *work)
{
uint32_t timeout_update = UINT32_MAX;
int64_t now = k_uptime_get();
struct net_if_dhcpv4 *current, *next;
ARG_UNUSED(work);
k_mutex_lock(&lock, K_FOREVER);
SYS_SLIST_FOR_EACH_CONTAINER_SAFE(&dhcpv4_ifaces, current, next, node) {
struct net_if *iface = CONTAINER_OF(
CONTAINER_OF(current, struct net_if_config, dhcpv4),
struct net_if, config);
uint32_t next_timeout;
next_timeout = dhcpv4_manage_timers(iface, now);
if (next_timeout < timeout_update) {
timeout_update = next_timeout;
}
}
k_mutex_unlock(&lock);
if (timeout_update != UINT32_MAX) {
NET_DBG("Waiting for %us", timeout_update);
k_work_reschedule(&timeout_work,
K_SECONDS(timeout_update));
}
}
/* Parse DHCPv4 options and retrieve relevant information
* as per RFC 2132.
*/
static bool dhcpv4_parse_options(struct net_pkt *pkt,
struct net_if *iface,
enum dhcpv4_msg_type *msg_type)
{
uint8_t cookie[4];
uint8_t length;
uint8_t type;
bool router_present = false;
if (net_pkt_read(pkt, cookie, sizeof(cookie)) ||
memcmp(magic_cookie, cookie, sizeof(magic_cookie))) {
NET_DBG("Incorrect magic cookie");
return false;
}
while (!net_pkt_read_u8(pkt, &type)) {
if (type == DHCPV4_OPTIONS_END) {
NET_DBG("options_end");
goto end;
}
if (net_pkt_read_u8(pkt, &length)) {
NET_ERR("option parsing, bad length");
return false;
}
switch (type) {
case DHCPV4_OPTIONS_SUBNET_MASK: {
struct in_addr netmask;
if (length != 4U) {
NET_ERR("options_subnet_mask, bad length");
return false;
}
if (net_pkt_read(pkt, netmask.s4_addr, length)) {
NET_ERR("options_subnet_mask, short packet");
return false;
}
net_if_ipv4_set_netmask(iface, &netmask);
NET_DBG("options_subnet_mask %s",
log_strdup(net_sprint_ipv4_addr(&netmask)));
break;
}
case DHCPV4_OPTIONS_ROUTER: {
struct in_addr router;
/* Router option may present 1 or more
* addresses for routers on the clients
* subnet. Routers should be listed in order
* of preference. Hence we choose the first
* and skip the rest.
*/
if (length % 4 != 0U || length < 4) {
NET_ERR("options_router, bad length");
return false;
}
if (net_pkt_read(pkt, router.s4_addr, 4) ||
net_pkt_skip(pkt, length - 4U)) {
NET_ERR("options_router, short packet");
return false;
}
NET_DBG("options_router: %s",
log_strdup(net_sprint_ipv4_addr(&router)));
net_if_ipv4_set_gw(iface, &router);
router_present = true;
break;
}
#if defined(CONFIG_DNS_RESOLVER)
case DHCPV4_OPTIONS_DNS_SERVER: {
struct dns_resolve_context *ctx;
struct sockaddr_in dns;
const struct sockaddr *dns_servers[] = {
(struct sockaddr *)&dns, NULL
};
int status;
/* DNS server option may present 1 or more
* addresses. Each 4 bytes in length. DNS
* servers should be listed in order
* of preference. Hence we choose the first
* and skip the rest.
*/
if (length % 4 != 0U) {
NET_ERR("options_dns, bad length");
return false;
}
(void)memset(&dns, 0, sizeof(dns));
if (net_pkt_read(pkt, dns.sin_addr.s4_addr, 4) ||
net_pkt_skip(pkt, length - 4U)) {
NET_ERR("options_dns, short packet");
return false;
}
ctx = dns_resolve_get_default();
dns.sin_family = AF_INET;
status = dns_resolve_reconfigure(ctx, NULL, dns_servers);
if (status < 0) {
NET_DBG("options_dns, failed to set "
"resolve address: %d", status);
return false;
}
break;
}
#endif
case DHCPV4_OPTIONS_LEASE_TIME:
if (length != 4U) {
NET_ERR("options_lease_time, bad length");
return false;
}
if (net_pkt_read_be32(
pkt, &iface->config.dhcpv4.lease_time) ||
!iface->config.dhcpv4.lease_time) {
NET_ERR("options_lease_time, wrong value");
return false;
}
NET_DBG("options_lease_time: %u",
iface->config.dhcpv4.lease_time);
break;
case DHCPV4_OPTIONS_RENEWAL:
if (length != 4U) {
NET_DBG("options_renewal, bad length");
return false;
}
if (net_pkt_read_be32(
pkt, &iface->config.dhcpv4.renewal_time) ||
!iface->config.dhcpv4.renewal_time) {
NET_DBG("options_renewal, wrong value");
return false;
}
NET_DBG("options_renewal: %u",
iface->config.dhcpv4.renewal_time);
break;
case DHCPV4_OPTIONS_REBINDING:
if (length != 4U) {
NET_DBG("options_rebinding, bad length");
return false;
}
if (net_pkt_read_be32(
pkt,
&iface->config.dhcpv4.rebinding_time) ||
!iface->config.dhcpv4.rebinding_time) {
NET_DBG("options_rebinding, wrong value");
return false;
}
NET_DBG("options_rebinding: %u",
iface->config.dhcpv4.rebinding_time);
break;
case DHCPV4_OPTIONS_SERVER_ID:
if (length != 4U) {
NET_DBG("options_server_id, bad length");
return false;
}
if (net_pkt_read(
pkt,
iface->config.dhcpv4.server_id.s4_addr,
length)) {
NET_DBG("options_server_id, read err");
return false;
}
NET_DBG("options_server_id: %s",
log_strdup(net_sprint_ipv4_addr(
&iface->config.dhcpv4.server_id)));
break;
case DHCPV4_OPTIONS_MSG_TYPE: {
if (length != 1U) {
NET_DBG("options_msg_type, bad length");
return false;
}
{
uint8_t val = 0U;
if (net_pkt_read_u8(pkt, &val)) {
NET_DBG("options_msg_type, read err");
return false;
}
*msg_type = val;
}
break;
}
default:
NET_DBG("option unknown: %d", type);
if (net_pkt_skip(pkt, length)) {
NET_DBG("option unknown, skip err");
return false;
}
break;
}
}
/* Invalid case: Options without DHCPV4_OPTIONS_END. */
return false;
end:
if (*msg_type == DHCPV4_MSG_TYPE_OFFER && !router_present) {
struct in_addr any = INADDR_ANY_INIT;
net_if_ipv4_set_gw(iface, &any);
}
return true;
}
static inline void dhcpv4_handle_msg_offer(struct net_if *iface)
{
switch (iface->config.dhcpv4.state) {
case NET_DHCPV4_DISABLED:
case NET_DHCPV4_INIT:
case NET_DHCPV4_REQUESTING:
case NET_DHCPV4_RENEWING:
case NET_DHCPV4_REBINDING:
case NET_DHCPV4_BOUND:
break;
case NET_DHCPV4_SELECTING:
dhcpv4_enter_requesting(iface);
break;
}
}
/* Must be invoked with lock held */
static void dhcpv4_handle_msg_ack(struct net_if *iface)
{
switch (iface->config.dhcpv4.state) {
case NET_DHCPV4_DISABLED:
case NET_DHCPV4_INIT:
case NET_DHCPV4_SELECTING:
case NET_DHCPV4_BOUND:
break;
case NET_DHCPV4_REQUESTING:
NET_INFO("Received: %s",
log_strdup(net_sprint_ipv4_addr(
&iface->config.dhcpv4.requested_ip)));
if (!net_if_ipv4_addr_add(iface,
&iface->config.dhcpv4.requested_ip,
NET_ADDR_DHCP,
iface->config.dhcpv4.lease_time)) {
NET_DBG("Failed to add IPv4 addr to iface %p", iface);
return;
}
dhcpv4_enter_bound(iface);
break;
case NET_DHCPV4_RENEWING:
case NET_DHCPV4_REBINDING:
/* TODO: If the renewal is success, update only
* vlifetime on iface.
*/
dhcpv4_enter_bound(iface);
break;
}
}
static void dhcpv4_handle_msg_nak(struct net_if *iface)
{
switch (iface->config.dhcpv4.state) {
case NET_DHCPV4_DISABLED:
case NET_DHCPV4_INIT:
case NET_DHCPV4_SELECTING:
case NET_DHCPV4_RENEWING:
case NET_DHCPV4_BOUND:
break;
case NET_DHCPV4_REQUESTING:
case NET_DHCPV4_REBINDING:
/* Restart the configuration process. */
dhcpv4_enter_selecting(iface);
break;
}
}
/* Takes and releases lock */
static void dhcpv4_handle_reply(struct net_if *iface,
enum dhcpv4_msg_type msg_type)
{
NET_DBG("state=%s msg=%s",
net_dhcpv4_state_name(iface->config.dhcpv4.state),
dhcpv4_msg_type_name(msg_type));
switch (msg_type) {
case DHCPV4_MSG_TYPE_OFFER:
dhcpv4_handle_msg_offer(iface);
break;
case DHCPV4_MSG_TYPE_ACK:
dhcpv4_handle_msg_ack(iface);
break;
case DHCPV4_MSG_TYPE_NAK:
dhcpv4_handle_msg_nak(iface);
break;
default:
NET_DBG("ignore message");
break;
}
}
static enum net_verdict net_dhcpv4_input(struct net_conn *conn,
struct net_pkt *pkt,
union net_ip_header *ip_hdr,
union net_proto_header *proto_hdr,
void *user_data)
{
NET_PKT_DATA_ACCESS_DEFINE(dhcp_access, struct dhcp_msg);
enum net_verdict verdict = NET_DROP;
enum dhcpv4_msg_type msg_type = 0;
struct dhcp_msg *msg;
struct net_if *iface;
if (!conn) {
NET_DBG("Invalid connection");
return NET_DROP;
}
if (!pkt) {
NET_DBG("Invalid packet");
return NET_DROP;
}
iface = net_pkt_iface(pkt);
if (!iface) {
NET_DBG("no iface");
return NET_DROP;
}
/* If the message is not DHCP then continue passing to
* related handlers.
*/
if (net_pkt_get_len(pkt) < NET_IPV4UDPH_LEN + sizeof(struct dhcp_msg)) {
NET_DBG("Input msg is not related to DHCPv4");
return NET_CONTINUE;
}
net_pkt_cursor_init(pkt);
if (net_pkt_skip(pkt, NET_IPV4UDPH_LEN)) {
return NET_DROP;
}
msg = (struct dhcp_msg *)net_pkt_get_data(pkt, &dhcp_access);
if (!msg) {
return NET_DROP;
}
NET_DBG("Received dhcp msg [op=0x%x htype=0x%x hlen=%u xid=0x%x "
"secs=%u flags=0x%x chaddr=%s",
msg->op, msg->htype, msg->hlen, ntohl(msg->xid),
msg->secs, msg->flags,
log_strdup(net_sprint_ll_addr(msg->chaddr, 6)));
NET_DBG(" ciaddr=%d.%d.%d.%d",
msg->ciaddr[0], msg->ciaddr[1], msg->ciaddr[2], msg->ciaddr[3]);
NET_DBG(" yiaddr=%d.%d.%d.%d",
msg->yiaddr[0], msg->yiaddr[1], msg->yiaddr[2], msg->yiaddr[3]);
NET_DBG(" siaddr=%d.%d.%d.%d",
msg->siaddr[0], msg->siaddr[1], msg->siaddr[2], msg->siaddr[3]);
NET_DBG(" giaddr=%d.%d.%d.%d]",
msg->giaddr[0], msg->giaddr[1], msg->giaddr[2], msg->giaddr[3]);
k_mutex_lock(&lock, K_FOREVER);
if (!(msg->op == DHCPV4_MSG_BOOT_REPLY &&
iface->config.dhcpv4.xid == ntohl(msg->xid) &&
!memcmp(msg->chaddr, net_if_get_link_addr(iface)->addr,
net_if_get_link_addr(iface)->len))) {
NET_DBG("Unexpected op (%d), xid (%x vs %x) or chaddr",
msg->op, iface->config.dhcpv4.xid, ntohl(msg->xid));
goto drop;
}
if (msg->hlen != net_if_get_link_addr(iface)->len) {
NET_DBG("Unexpected hlen (%d)", msg->hlen);
goto drop;
}
memcpy(iface->config.dhcpv4.requested_ip.s4_addr,
msg->yiaddr, sizeof(msg->yiaddr));
net_pkt_acknowledge_data(pkt, &dhcp_access);
/* SNAME, FILE are not used at the moment, skip it */
if (net_pkt_skip(pkt, SIZE_OF_SNAME + SIZE_OF_FILE)) {
NET_DBG("short packet while skipping sname");
goto drop;
}
if (!dhcpv4_parse_options(pkt, iface, &msg_type)) {
goto drop;
}
net_pkt_unref(pkt);
dhcpv4_handle_reply(iface, msg_type);
verdict = NET_OK;
drop:
k_mutex_unlock(&lock);
return verdict;
}
static void dhcpv4_iface_event_handler(struct net_mgmt_event_callback *cb,
uint32_t mgmt_event, struct net_if *iface)
{
sys_snode_t *node = NULL;
k_mutex_lock(&lock, K_FOREVER);
SYS_SLIST_FOR_EACH_NODE(&dhcpv4_ifaces, node) {
if (node == &iface->config.dhcpv4.node) {
break;
}
}
if (node == NULL) {
goto out;
}
if (mgmt_event == NET_EVENT_IF_DOWN) {
NET_DBG("Interface %p going down", iface);
if (iface->config.dhcpv4.state == NET_DHCPV4_BOUND) {
iface->config.dhcpv4.attempts = 0U;
iface->config.dhcpv4.state = NET_DHCPV4_RENEWING;
NET_DBG("enter state=%s", net_dhcpv4_state_name(
iface->config.dhcpv4.state));
}
} else if (mgmt_event == NET_EVENT_IF_UP) {
NET_DBG("Interface %p coming up", iface);
/* We should not call dhcpv4_send_request() directly here as
* the CONFIG_NET_MGMT_EVENT_STACK_SIZE is not large
* enough. Instead we can force a request timeout
* which will then call dhcpv4_send_request() automatically.
*/
dhcpv4_immediate_timeout(&iface->config.dhcpv4);
}
out:
k_mutex_unlock(&lock);
}
const char *net_dhcpv4_state_name(enum net_dhcpv4_state state)
{
static const char * const name[] = {
"disabled",
"init",
"selecting",
"requesting",
"renewing",
"rebinding",
"bound",
};
__ASSERT_NO_MSG(state >= 0 && state < sizeof(name));
return name[state];
}
void net_dhcpv4_start(struct net_if *iface)
{
uint32_t timeout;
uint32_t entropy;
net_mgmt_event_notify(NET_EVENT_IPV4_DHCP_START, iface);
k_mutex_lock(&lock, K_FOREVER);
switch (iface->config.dhcpv4.state) {
case NET_DHCPV4_DISABLED:
iface->config.dhcpv4.state = NET_DHCPV4_INIT;
NET_DBG("iface %p state=%s", iface,
net_dhcpv4_state_name(iface->config.dhcpv4.state));
/* We need entropy for both an XID and a random delay
* before sending the initial discover message.
*/
entropy = sys_rand32_get();
/* A DHCP client MUST choose xid's in such a way as to
* minimize the change of using and xid identical to
* one used by another client. Choose a random xid st
* startup and increment it on each new request.
*/
iface->config.dhcpv4.xid = entropy;
/* RFC2131 4.1.1 requires we wait a random period
* between 1 and 10 seconds before sending the initial
* discover.
*/
timeout = entropy %
(CONFIG_NET_DHCPV4_INITIAL_DELAY_MAX -
DHCPV4_INITIAL_DELAY_MIN) +
DHCPV4_INITIAL_DELAY_MIN;
NET_DBG("wait timeout=%us", timeout);
if (sys_slist_is_empty(&dhcpv4_ifaces)) {
net_mgmt_add_event_callback(&mgmt4_cb);
}
sys_slist_append(&dhcpv4_ifaces,
&iface->config.dhcpv4.node);
dhcpv4_set_timeout(&iface->config.dhcpv4, timeout);
break;
case NET_DHCPV4_INIT:
case NET_DHCPV4_SELECTING:
case NET_DHCPV4_REQUESTING:
case NET_DHCPV4_RENEWING:
case NET_DHCPV4_REBINDING:
case NET_DHCPV4_BOUND:
break;
}
k_mutex_unlock(&lock);
}
void net_dhcpv4_stop(struct net_if *iface)
{
k_mutex_lock(&lock, K_FOREVER);
switch (iface->config.dhcpv4.state) {
case NET_DHCPV4_DISABLED:
break;
case NET_DHCPV4_RENEWING:
case NET_DHCPV4_BOUND:
if (!net_if_ipv4_addr_rm(iface,
&iface->config.dhcpv4.requested_ip)) {
NET_DBG("Failed to remove addr from iface");
}
__fallthrough;
case NET_DHCPV4_INIT:
case NET_DHCPV4_SELECTING:
case NET_DHCPV4_REQUESTING:
case NET_DHCPV4_REBINDING:
iface->config.dhcpv4.state = NET_DHCPV4_DISABLED;
NET_DBG("state=%s",
net_dhcpv4_state_name(iface->config.dhcpv4.state));
sys_slist_find_and_remove(&dhcpv4_ifaces,
&iface->config.dhcpv4.node);
if (sys_slist_is_empty(&dhcpv4_ifaces)) {
/* Best effort cancel. Handler is safe to invoke if
* cancellation is unsuccessful.
*/
(void)k_work_cancel_delayable(&timeout_work);
net_mgmt_del_event_callback(&mgmt4_cb);
}
break;
}
net_mgmt_event_notify(NET_EVENT_IPV4_DHCP_STOP, iface);
k_mutex_unlock(&lock);
}
int net_dhcpv4_init(void)
{
struct sockaddr local_addr;
int ret;
NET_DBG("");
net_ipaddr_copy(&net_sin(&local_addr)->sin_addr,
net_ipv4_unspecified_address());
local_addr.sa_family = AF_INET;
/* Register UDP input callback on
* DHCPV4_SERVER_PORT(67) and DHCPV4_CLIENT_PORT(68) for
* all dhcpv4 related incoming packets.
*/
ret = net_udp_register(AF_INET, NULL, &local_addr,
DHCPV4_SERVER_PORT,
DHCPV4_CLIENT_PORT,
NULL, net_dhcpv4_input, NULL, NULL);
if (ret < 0) {
NET_DBG("UDP callback registration failed");
return ret;
}
k_work_init_delayable(&timeout_work, dhcpv4_timeout);
/* Catch network interface UP or DOWN events and renew the address
* if interface is coming back up again.
*/
net_mgmt_init_event_callback(&mgmt4_cb, dhcpv4_iface_event_handler,
NET_EVENT_IF_DOWN | NET_EVENT_IF_UP);
return 0;
}