2 * Copyright (c) 2008, 2009, 2010 Nicira Networks.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 #include "dhcp-client.h"
19 #include <arpa/inet.h>
26 #include <sys/types.h>
31 #include "dynamic-string.h"
35 #include "poll-loop.h"
40 VLOG_DEFINE_THIS_MODULE(dhcp_client
)
42 #define DHCLIENT_STATES \
43 DHCLIENT_STATE(INIT, 1 << 0) \
44 DHCLIENT_STATE(INIT_REBOOT, 1 << 1) \
45 DHCLIENT_STATE(REBOOTING, 1 << 2) \
46 DHCLIENT_STATE(SELECTING, 1 << 3) \
47 DHCLIENT_STATE(REQUESTING, 1 << 4) \
48 DHCLIENT_STATE(BOUND, 1 << 5) \
49 DHCLIENT_STATE(RENEWING, 1 << 6) \
50 DHCLIENT_STATE(REBINDING, 1 << 7) \
51 DHCLIENT_STATE(RELEASED, 1 << 8)
53 #define DHCLIENT_STATE(NAME, VALUE) S_##NAME = VALUE,
58 static struct vlog_rate_limit rl
= VLOG_RATE_LIMIT_INIT(60, 60);
61 state_name(enum dhclient_state state
)
64 #define DHCLIENT_STATE(NAME, VALUE) case S_##NAME: return #NAME;
73 struct netdev
*netdev
;
75 void (*modify_request
)(struct dhcp_msg
*, void *aux
);
76 bool (*validate_offer
)(const struct dhcp_msg
*, void *aux
);
80 enum dhclient_state state
;
81 unsigned int state_entered
; /* When we transitioned to this state. */
82 uint32_t xid
; /* In host byte order. */
83 uint32_t ipaddr
, netmask
, router
;
85 struct dhcp_msg
*binding
;
88 unsigned int retransmit
, delay
; /* Used by send_reliably(). */
89 unsigned int max_timeout
;
91 unsigned int init_delay
; /* Used by S_INIT. */
93 time_t lease_expiration
;
94 unsigned int bound_timeout
;
95 unsigned int renewing_timeout
;
96 unsigned int rebinding_timeout
;
98 /* Used by dhclient_run() and dhclient_wait() */
99 unsigned int min_timeout
;
102 /* Set when we send out a DHCPDISCOVER message. */
108 /* Minimum acceptable lease time, in seconds. */
109 #define MIN_ACCEPTABLE_LEASE 15
111 static void state_transition(struct dhclient
*, enum dhclient_state
);
112 static unsigned int elapsed_in_this_state(const struct dhclient
*cli
);
113 static bool timeout(struct dhclient
*, unsigned int secs
);
115 static void dhclient_msg_init(struct dhclient
*, enum dhcp_msg_type
,
117 static void send_reliably(struct dhclient
*cli
,
118 void (*make_packet
)(struct dhclient
*,
120 static bool do_receive_msg(struct dhclient
*, struct dhcp_msg
*);
121 static void do_send_msg(struct dhclient
*, const struct dhcp_msg
*);
122 static bool receive_ack(struct dhclient
*);
124 static unsigned int fuzz(unsigned int x
, int max_fuzz
);
125 static unsigned int calc_t2(unsigned int lease
);
126 static unsigned int calc_t1(unsigned int lease
, unsigned int t2
);
128 static unsigned int clamp(unsigned int x
, unsigned int min
, unsigned int max
);
130 /* Creates a new DHCP client to configure the network device 'netdev_name'
133 * If 'modify_request' is non-null, then each DHCP message to discover or
134 * request an address will be passed to it (along with auxiliary data 'aux').
135 * It may then add any desired options to the message for transmission.
137 * If 'validate_offer' is non-null, then each DHCP message that offers an
138 * address will be passed to it (along with auxiliary data 'aux') for
139 * validation: if it returns true, the address will accepted; otherwise, it
142 * The DHCP client will not start advertising for an IP address until
143 * dhclient_init() is called.
145 * If successful, returns 0 and sets '*cli' to the new DHCP client. Otherwise,
146 * returns a positive errno value and sets '*cli' to a null pointer. */
148 dhclient_create(const char *netdev_name
,
149 void (*modify_request
)(struct dhcp_msg
*, void *aux
),
150 bool (*validate_offer
)(const struct dhcp_msg
*, void *aux
),
151 void *aux
, struct dhclient
**cli_
)
153 struct dhclient
*cli
;
154 struct netdev_options netdev_options
;
155 struct netdev
*netdev
;
160 memset(&netdev_options
, 0, sizeof netdev_options
);
161 netdev_options
.name
= netdev_name
;
162 netdev_options
.ethertype
= ETH_TYPE_IP
;
164 error
= netdev_open(&netdev_options
, &netdev
);
165 /* XXX install socket filter to catch only DHCP packets. */
167 VLOG_ERR("%s: could not open network device: %s",
168 netdev_name
, strerror(error
));
172 error
= netdev_turn_flags_on(netdev
, NETDEV_UP
, false);
174 VLOG_ERR("%s: could not bring device up: %s",
175 netdev_name
, strerror(error
));
176 netdev_close(netdev
);
180 cli
= xzalloc(sizeof *cli
);
181 cli
->modify_request
= modify_request
;
182 cli
->validate_offer
= validate_offer
;
184 cli
->netdev
= netdev
;
185 cli
->state
= S_RELEASED
;
186 cli
->state_entered
= time_now();
187 cli
->xid
= random_uint32();
190 cli
->retransmit
= cli
->delay
= 0;
191 cli
->max_timeout
= 64;
192 cli
->min_timeout
= 1;
199 /* Sets the maximum amount of timeout that 'cli' will wait for a reply from
200 * the DHCP server before retransmitting, in seconds, to 'max_timeout'. The
201 * default is 64 seconds. */
203 dhclient_set_max_timeout(struct dhclient
*cli
, unsigned int max_timeout
)
205 cli
->max_timeout
= MAX(2, max_timeout
);
208 /* Destroys 'cli' and frees all related resources. */
210 dhclient_destroy(struct dhclient
*cli
)
213 dhcp_msg_uninit(cli
->binding
);
215 netdev_close(cli
->netdev
);
221 /* Returns the network device in use by 'cli'. The caller must not destroy
222 * the returned device. */
224 dhclient_get_netdev(struct dhclient
*cli
)
229 /* Returns the name of the network device in use by 'cli'. The caller must
230 * not modify or destroy the returned string. */
232 dhclient_get_name(const struct dhclient
*cli
)
234 return netdev_get_name(cli
->netdev
);
237 /* Forces 'cli' into a (re)initialization state, in which no address is bound
238 * but the client is advertising to obtain one. If 'requested_ip' is nonzero,
239 * then the client will attempt to re-bind to that IP address; otherwise, it
240 * will not ask for any particular address. */
242 dhclient_init(struct dhclient
*cli
, uint32_t requested_ip
)
244 state_transition(cli
, requested_ip
? S_INIT_REBOOT
: S_INIT
);
245 cli
->ipaddr
= requested_ip
;
246 cli
->min_timeout
= 0;
250 /* Forces 'cli' to release its bound IP address (if any). The client will not
251 * advertise for a new address until dhclient_init() is called again. */
253 dhclient_release(struct dhclient
*cli
)
255 if (dhclient_is_bound(cli
)) {
257 dhclient_msg_init(cli
, DHCPRELEASE
, &msg
);
258 msg
.ciaddr
= cli
->ipaddr
;
259 do_send_msg(cli
, &msg
);
260 dhcp_msg_uninit(&msg
);
262 state_transition(cli
, S_RELEASED
);
263 cli
->min_timeout
= UINT_MAX
;
267 do_force_renew(struct dhclient
*cli
, int deadline
)
269 time_t now
= time_now();
270 unsigned int lease_left
= sat_sub(cli
->lease_expiration
, now
);
271 if (lease_left
<= deadline
) {
272 if (cli
->state
& (S_RENEWING
| S_REBINDING
)) {
275 deadline
= lease_left
;
277 if (cli
->state
& (S_BOUND
| S_RENEWING
)) {
278 state_transition(cli
, S_RENEWING
);
279 cli
->renewing_timeout
= deadline
* 3 / 4;
280 cli
->rebinding_timeout
= deadline
* 1 / 4;
282 state_transition(cli
, S_REBINDING
);
283 cli
->rebinding_timeout
= deadline
;
285 cli
->min_timeout
= 0;
288 /* Forces 'cli' to attempt to renew the lease its current IP address (if any)
289 * within 'deadline' seconds. If the deadline is not met, then the client
290 * gives up its IP address binding and re-starts the DHCP process. */
292 dhclient_force_renew(struct dhclient
*cli
, int deadline
)
294 /* Drain the receive queue so that we know that any DHCPACK we process is
295 * freshly received. */
296 netdev_drain(cli
->netdev
);
298 switch (cli
->state
) {
309 do_force_renew(cli
, deadline
);
313 dhclient_init(cli
, 0);
318 /* Returns true if 'cli' is bound to an IP address, false otherwise. */
320 dhclient_is_bound(const struct dhclient
*cli
)
322 return cli
->state
& (S_BOUND
| S_RENEWING
| S_REBINDING
);
325 /* Returns true if 'cli' has changed from bound to unbound, or vice versa, at
326 * least once since the last time this function was called. */
328 dhclient_changed(struct dhclient
*cli
)
330 bool changed
= cli
->changed
;
335 /* Returns 'cli''s current state, as a string. The caller must not modify or
336 * free the string. */
338 dhclient_get_state(const struct dhclient
*cli
)
340 return state_name(cli
->state
);
343 /* Returns the number of seconds spent so far in 'cli''s current state. */
345 dhclient_get_state_elapsed(const struct dhclient
*cli
)
347 return elapsed_in_this_state(cli
);
350 /* If 'cli' is bound, returns the number of seconds remaining in its lease;
351 * otherwise, returns 0. */
353 dhclient_get_lease_remaining(const struct dhclient
*cli
)
355 if (dhclient_is_bound(cli
)) {
356 time_t now
= time_now();
357 return cli
->lease_expiration
> now
? cli
->lease_expiration
- now
: 0;
363 /* If 'cli' is bound to an IP address, returns that IP address; otherwise,
366 dhclient_get_ip(const struct dhclient
*cli
)
368 return dhclient_is_bound(cli
) ? cli
->ipaddr
: 0;
371 /* If 'cli' is bound to an IP address, returns the netmask for that IP address;
372 * otherwise, returns 0. */
374 dhclient_get_netmask(const struct dhclient
*cli
)
376 return dhclient_is_bound(cli
) ? cli
->netmask
: 0;
379 /* If 'cli' is bound to an IP address and 'cli' has a default gateway, returns
380 * that default gateway; otherwise, returns 0. */
382 dhclient_get_router(const struct dhclient
*cli
)
384 return dhclient_is_bound(cli
) ? cli
->router
: 0;
387 /* If 'cli' is bound to an IP address, returns the DHCP message that was
388 * received to obtain that IP address (so that the caller can obtain additional
389 * options from it). Otherwise, returns a null pointer. */
390 const struct dhcp_msg
*
391 dhclient_get_config(const struct dhclient
*cli
)
393 return dhclient_is_bound(cli
) ? cli
->binding
: NULL
;
396 /* Configures the network device backing 'cli' to the network address and other
397 * parameters obtained via DHCP. If no address is bound on 'cli', removes any
398 * configured address from 'cli'.
400 * To use a dhclient as a regular DHCP client that binds and unbinds from IP
401 * addresses in the usual fashion, call this function after dhclient_run() if
402 * anything has changed, like so:
405 * if (dhclient_changed(cli)) {
406 * dhclient_configure_netdev(cli);
411 dhclient_configure_netdev(struct dhclient
*cli
)
413 const char *cli_name
= dhclient_get_name(cli
);
414 struct in_addr addr
= { dhclient_get_ip(cli
) };
415 struct in_addr mask
= { dhclient_get_netmask(cli
) };
416 struct in_addr router
= { dhclient_get_router(cli
) };
419 error
= netdev_set_in4(cli
->netdev
, addr
, mask
);
421 VLOG_ERR("%s: could not set address "IP_FMT
"/"IP_FMT
" (%s)",
422 cli_name
, IP_ARGS(&addr
.s_addr
), IP_ARGS(&mask
.s_addr
),
426 if (!error
&& router
.s_addr
) {
427 error
= netdev_add_router(cli
->netdev
, router
);
429 VLOG_ERR("%s: failed to add default route to "IP_FMT
" (%s)",
430 cli_name
, IP_ARGS(&router
), strerror(error
));
437 /* If 'cli' is bound and the binding includes DNS domain parameters, updates
438 * /etc/resolv.conf will be updated to match the received parameters. Returns
439 * 0 if successful, otherwise a positive errno value. */
441 dhclient_update_resolv_conf(struct dhclient
*cli
)
443 const char *cli_name
= dhclient_get_name(cli
);
446 bool has_domain_name
;
451 if (!dhclient_is_bound(cli
)) {
454 if (!dhcp_msg_get_ip(cli
->binding
, DHCP_CODE_DNS_SERVER
, 0, &dns_server
)) {
455 VLOG_DBG("%s: binding does not include any DNS servers", cli_name
);
459 sprintf(new_name
, "/etc/resolv.conf.tmp%ld", (long int) getpid());
460 new = fopen(new_name
, "w");
462 VLOG_WARN("%s: could not create %s (%s)",
463 cli_name
, new_name
, strerror(errno
));
467 domain_name
= dhcp_msg_get_string(cli
->binding
, DHCP_CODE_DOMAIN_NAME
);
468 has_domain_name
= domain_name
!= NULL
;
470 if (strspn(domain_name
, "-_.0123456789abcdefghijklmnopqrstuvwxyz"
471 "ABCDEFGHIJKLMNOPQRSTUVWXYZ") == strlen(domain_name
)) {
472 fprintf(new, "domain %s\n", domain_name
);
474 VLOG_WARN("%s: ignoring invalid domain name %s",
475 cli_name
, domain_name
);
476 has_domain_name
= false;
479 VLOG_DBG("%s: binding does not include domain name", cli_name
);
483 for (i
= 0; dhcp_msg_get_ip(cli
->binding
, DHCP_CODE_DNS_SERVER
,
484 i
, &dns_server
); i
++) {
485 fprintf(new, "nameserver "IP_FMT
"\n", IP_ARGS(&dns_server
));
488 old
= fopen("/etc/resolv.conf", "r");
492 while (fgets(line
, sizeof line
, old
)) {
493 char *kw
= xmemdup0(line
, strcspn(line
, " \t\r\n"));
494 if (strcmp(kw
, "nameserver")
496 || (strcmp(kw
, "domain") && strcmp(kw
, "search")))) {
503 VLOG_DBG("%s: failed to open /etc/resolv.conf (%s)",
504 cli_name
, strerror(errno
));
507 if (fclose(new) < 0) {
508 VLOG_WARN("%s: closing %s failed (%s)",
509 cli_name
, new_name
, strerror(errno
));
513 if (rename(new_name
, "/etc/resolv.conf") < 0) {
514 VLOG_WARN("%s: failed to rename %s to /etc/resolv.conf (%s)",
515 cli_name
, new_name
, strerror(errno
));
525 make_dhcpdiscover(struct dhclient
*cli
, struct dhcp_msg
*msg
)
527 cli
->secs
= elapsed_in_this_state(cli
);
528 dhclient_msg_init(cli
, DHCPDISCOVER
, msg
);
530 dhcp_msg_put_ip(msg
, DHCP_CODE_REQUESTED_IP
, cli
->ipaddr
);
535 make_dhcprequest(struct dhclient
*cli
, struct dhcp_msg
*msg
)
537 dhclient_msg_init(cli
, DHCPREQUEST
, msg
);
538 msg
->ciaddr
= dhclient_get_ip(cli
);
539 if (cli
->state
== S_REQUESTING
) {
540 dhcp_msg_put_ip(msg
, DHCP_CODE_SERVER_IDENTIFIER
, cli
->server_ip
);
542 dhcp_msg_put_ip(msg
, DHCP_CODE_REQUESTED_IP
, cli
->ipaddr
);
546 do_init(struct dhclient
*cli
, enum dhclient_state next_state
)
548 if (!cli
->init_delay
) {
549 cli
->init_delay
= fuzz(2, 1);
551 if (timeout(cli
, cli
->init_delay
)) {
552 state_transition(cli
, next_state
);
557 dhclient_run_INIT(struct dhclient
*cli
)
559 do_init(cli
, S_SELECTING
);
563 dhclient_run_INIT_REBOOT(struct dhclient
*cli
)
565 do_init(cli
, S_REBOOTING
);
569 dhclient_run_REBOOTING(struct dhclient
*cli
)
571 send_reliably(cli
, make_dhcprequest
);
572 if (!receive_ack(cli
) && timeout(cli
, 60)) {
573 state_transition(cli
, S_INIT
);
578 dhcp_receive(struct dhclient
*cli
, unsigned int msgs
, struct dhcp_msg
*msg
)
580 while (do_receive_msg(cli
, msg
)) {
581 const char *cli_name
= dhclient_get_name(cli
);
583 if (msg
->type
> 31 || !((1u << msg
->type
) & msgs
)) {
584 VLOG_DBG_RL(&rl
, "%s: received unexpected %s in %s state: %s",
586 dhcp_type_name(msg
->type
), state_name(cli
->state
),
587 dhcp_msg_to_string(msg
, false, &cli
->s
));
588 } else if (msg
->xid
!= cli
->xid
) {
589 VLOG_DBG_RL(&rl
, "%s: ignoring %s with xid != %08"PRIx32
" "
590 "in %s state: %s", cli_name
,
591 dhcp_type_name(msg
->type
), msg
->xid
,
592 state_name(cli
->state
),
593 dhcp_msg_to_string(msg
, false, &cli
->s
));
597 dhcp_msg_uninit(msg
);
603 validate_offered_options(struct dhclient
*cli
, const struct dhcp_msg
*msg
)
605 const char *cli_name
= dhclient_get_name(cli
);
606 uint32_t lease
, netmask
;
608 if (!dhcp_msg_get_secs(msg
, DHCP_CODE_LEASE_TIME
, 0, &lease
)) {
609 VLOG_WARN_RL(&rl
, "%s: %s lacks lease time (%s)",
610 cli_name
, dhcp_type_name(msg
->type
),
611 dhcp_msg_to_string(msg
, false, &cli
->s
));
612 } else if (!dhcp_msg_get_ip(msg
, DHCP_CODE_SUBNET_MASK
, 0, &netmask
)) {
613 VLOG_WARN_RL(&rl
, "%s: %s lacks netmask (%s)",
614 cli_name
, dhcp_type_name(msg
->type
),
615 dhcp_msg_to_string(msg
, false, &cli
->s
));
616 } else if (lease
< MIN_ACCEPTABLE_LEASE
) {
617 VLOG_WARN_RL(&rl
, "%s: ignoring %s with %"PRIu32
"-second "
618 "lease time (%s)", cli_name
,
619 dhcp_type_name(msg
->type
), lease
,
620 dhcp_msg_to_string(msg
, false, &cli
->s
));
621 } else if (cli
->validate_offer
&& !cli
->validate_offer(msg
, cli
->aux
)) {
622 VLOG_DBG_RL(&rl
, "%s: client validation hook refused offer (%s)",
623 cli_name
, dhcp_msg_to_string(msg
, false, &cli
->s
));
631 dhclient_run_SELECTING(struct dhclient
*cli
)
633 const char *cli_name
= dhclient_get_name(cli
);
636 send_reliably(cli
, make_dhcpdiscover
);
637 if (cli
->server_ip
&& timeout(cli
, 60)) {
639 state_transition(cli
, S_INIT
);
641 for (; dhcp_receive(cli
, 1u << DHCPOFFER
, &msg
); dhcp_msg_uninit(&msg
)) {
642 if (!validate_offered_options(cli
, &msg
)) {
645 if (!dhcp_msg_get_ip(&msg
, DHCP_CODE_SERVER_IDENTIFIER
,
646 0, &cli
->server_ip
)) {
647 VLOG_WARN_RL(&rl
, "%s: DHCPOFFER lacks server identifier (%s)",
648 cli_name
, dhcp_msg_to_string(&msg
, false, &cli
->s
));
652 VLOG_DBG_RL(&rl
, "%s: accepting DHCPOFFER (%s)",
653 cli_name
, dhcp_msg_to_string(&msg
, false, &cli
->s
));
654 cli
->ipaddr
= msg
.yiaddr
;
655 state_transition(cli
, S_REQUESTING
);
661 same_binding(const char *cli_name
,
662 const struct dhcp_msg
*old
, const struct dhcp_msg
*new)
664 static const int codes
[] = {
665 DHCP_CODE_SUBNET_MASK
,
667 DHCP_CODE_DNS_SERVER
,
669 DHCP_CODE_DOMAIN_NAME
,
672 DHCP_CODE_BROADCAST_ADDRESS
,
673 DHCP_CODE_STATIC_ROUTE
,
674 DHCP_CODE_ARP_CACHE_TIMEOUT
,
675 DHCP_CODE_ETHERNET_ENCAPSULATION
,
677 DHCP_CODE_SERVER_IDENTIFIER
,
678 DHCP_CODE_OFP_CONTROLLER_VCONN
,
679 DHCP_CODE_OFP_PKI_URI
,
684 if (old
->yiaddr
!= new->yiaddr
) {
685 VLOG_WARN("%s: DHCP binding changed IP address "
686 "from "IP_FMT
" to "IP_FMT
,
687 cli_name
, IP_ARGS(&old
->yiaddr
), IP_ARGS(&new->yiaddr
));
690 for (i
= 0; i
< ARRAY_SIZE(codes
); i
++) {
692 const struct dhcp_option
*old_opt
= &old
->options
[code
];
693 const struct dhcp_option
*new_opt
= &new->options
[code
];
694 if (!dhcp_option_equals(old_opt
, new_opt
)) {
695 struct ds old_string
= DS_EMPTY_INITIALIZER
;
696 struct ds new_string
= DS_EMPTY_INITIALIZER
;
697 VLOG_WARN("%s: DHCP binding changed option from %s to %s",
699 dhcp_option_to_string(old_opt
, code
, &old_string
),
700 dhcp_option_to_string(new_opt
, code
, &new_string
));
701 ds_destroy(&old_string
);
702 ds_destroy(&new_string
);
710 receive_ack(struct dhclient
*cli
)
714 if (!dhcp_receive(cli
, (1u << DHCPACK
) | (1u << DHCPNAK
), &msg
)) {
716 } else if (msg
.type
== DHCPNAK
) {
717 dhcp_msg_uninit(&msg
);
718 state_transition(cli
, S_INIT
);
720 } else if (!validate_offered_options(cli
, &msg
)) {
721 dhcp_msg_uninit(&msg
);
724 uint32_t lease
= 0, t1
= 0, t2
= 0;
727 if (!same_binding(dhclient_get_name(cli
), cli
->binding
, &msg
)) {
730 dhcp_msg_uninit(cli
->binding
);
732 cli
->binding
= xmalloc(sizeof *cli
->binding
);
734 dhcp_msg_copy(cli
->binding
, &msg
);
736 dhcp_msg_get_secs(&msg
, DHCP_CODE_LEASE_TIME
, 0, &lease
);
737 dhcp_msg_get_secs(&msg
, DHCP_CODE_T1
, 0, &t1
);
738 dhcp_msg_get_secs(&msg
, DHCP_CODE_T2
, 0, &t2
);
739 assert(lease
>= MIN_ACCEPTABLE_LEASE
);
741 if (!t2
|| t2
>= lease
) {
744 if (!t1
|| t1
>= t2
) {
745 t1
= calc_t1(lease
, t2
);
748 cli
->lease_expiration
= sat_add(time_now(), lease
);
749 cli
->bound_timeout
= t1
;
750 cli
->renewing_timeout
= t2
- t1
;
751 cli
->rebinding_timeout
= lease
- t2
;
753 cli
->ipaddr
= msg
.yiaddr
;
754 dhcp_msg_get_ip(&msg
, DHCP_CODE_SUBNET_MASK
, 0, &cli
->netmask
);
755 if (!dhcp_msg_get_ip(&msg
, DHCP_CODE_ROUTER
, 0, &cli
->router
)) {
756 cli
->router
= INADDR_ANY
;
758 state_transition(cli
, S_BOUND
);
759 VLOG_DBG("%s: bound (%s)", dhclient_get_name(cli
),
760 dhcp_msg_to_string(&msg
, false, &cli
->s
));
766 dhclient_run_REQUESTING(struct dhclient
*cli
)
768 send_reliably(cli
, make_dhcprequest
);
769 if (!receive_ack(cli
) && timeout(cli
, 60)) {
770 state_transition(cli
, S_INIT
);
775 dhclient_run_BOUND(struct dhclient
*cli
)
777 if (timeout(cli
, cli
->bound_timeout
)) {
778 state_transition(cli
, S_RENEWING
);
783 dhclient_run_RENEWING(struct dhclient
*cli
)
785 send_reliably(cli
, make_dhcprequest
);
786 if (!receive_ack(cli
) && timeout(cli
, cli
->renewing_timeout
)) {
787 state_transition(cli
, S_REBINDING
);
792 dhclient_run_REBINDING(struct dhclient
*cli
)
794 send_reliably(cli
, make_dhcprequest
);
795 if (!receive_ack(cli
) && timeout(cli
, cli
->rebinding_timeout
)) {
796 state_transition(cli
, S_INIT
);
801 dhclient_run_RELEASED(struct dhclient
*cli OVS_UNUSED
)
806 /* Processes the DHCP protocol for 'cli'. */
808 dhclient_run(struct dhclient
*cli
)
812 old_state
= cli
->state
;
813 cli
->min_timeout
= UINT_MAX
;
815 switch (cli
->state
) {
816 #define DHCLIENT_STATE(NAME, VALUE) \
817 case S_##NAME: dhclient_run_##NAME(cli); break;
819 #undef DHCLIENT_STATE
823 } while (cli
->state
!= old_state
);
826 /* Sets up poll timeouts to wake up the poll loop when 'cli' needs to do some
829 dhclient_wait(struct dhclient
*cli
)
831 if (cli
->min_timeout
!= UINT_MAX
) {
832 long long int wake
= sat_add(cli
->state_entered
, cli
->min_timeout
);
833 poll_timer_wait_until(wake
* 1000);
835 /* Reset timeout to 1 second. This will have no effect ordinarily, because
836 * dhclient_run() will typically set it back to a higher value. If,
837 * however, the caller fails to call dhclient_run() before its next call to
838 * dhclient_wait() we won't potentially block forever. */
839 cli
->min_timeout
= 1;
841 if (cli
->state
& (S_SELECTING
| S_REQUESTING
| S_RENEWING
| S_REBINDING
)) {
842 netdev_recv_wait(cli
->netdev
);
847 state_transition(struct dhclient
*cli
, enum dhclient_state state
)
849 const char *cli_name
= dhclient_get_name(cli
);
850 bool was_bound
= dhclient_is_bound(cli
);
853 if (cli
->state
!= state
) {
854 VLOG_DBG("%s: entering %s", cli_name
, state_name(state
));
857 cli
->state_entered
= time_now();
858 cli
->retransmit
= cli
->delay
= 0;
859 am_bound
= dhclient_is_bound(cli
);
860 if (was_bound
!= am_bound
) {
863 assert(cli
->binding
!= NULL
);
864 VLOG_INFO("%s: obtained address "IP_FMT
", netmask "IP_FMT
,
866 IP_ARGS(&cli
->ipaddr
), IP_ARGS(&cli
->netmask
));
868 VLOG_INFO("%s: obtained default gateway "IP_FMT
,
869 cli_name
, IP_ARGS(&cli
->router
));
872 dhcp_msg_uninit(cli
->binding
);
876 VLOG_INFO("%s: network address unbound", cli_name
);
879 if (cli
->state
& (S_SELECTING
| S_REQUESTING
| S_REBOOTING
)) {
880 netdev_drain(cli
->netdev
);
885 send_reliably(struct dhclient
*cli
,
886 void (*make_packet
)(struct dhclient
*, struct dhcp_msg
*))
888 if (timeout(cli
, cli
->retransmit
)) {
890 make_packet(cli
, &msg
);
891 if (cli
->modify_request
) {
892 cli
->modify_request(&msg
, cli
->aux
);
894 do_send_msg(cli
, &msg
);
895 cli
->delay
= MIN(cli
->max_timeout
, MAX(4, cli
->delay
* 2));
896 cli
->retransmit
+= fuzz(cli
->delay
, 1);
897 timeout(cli
, cli
->retransmit
);
898 dhcp_msg_uninit(&msg
);
903 dhclient_msg_init(struct dhclient
*cli
, enum dhcp_msg_type type
,
904 struct dhcp_msg
*msg
)
907 msg
->op
= DHCP_BOOTREQUEST
;
909 msg
->secs
= cli
->secs
;
911 netdev_get_etheraddr(cli
->netdev
, msg
->chaddr
);
914 /* If time goes backward this returns a large number, which makes it look like
915 * we've been in the current state a very long time. That's probably
916 * fine for that corner case--we'll just expire our lease, etc., and try to
919 elapsed_in_this_state(const struct dhclient
*cli
)
921 return time_now() - cli
->state_entered
;
925 timeout(struct dhclient
*cli
, unsigned int secs
)
927 cli
->min_timeout
= MIN(cli
->min_timeout
, secs
);
928 return time_now() >= sat_add(cli
->state_entered
, secs
);
932 do_receive_msg(struct dhclient
*cli
, struct dhcp_msg
*msg
)
934 const char *cli_name
= dhclient_get_name(cli
);
935 uint8_t cli_mac
[ETH_ADDR_LEN
];
939 netdev_get_mtu(cli
->netdev
, &mtu
);
940 ofpbuf_init(&b
, mtu
+ VLAN_ETH_HEADER_LEN
);
941 netdev_get_etheraddr(cli
->netdev
, cli_mac
);
942 for (; cli
->received
< 50; cli
->received
++) {
943 const struct ip_header
*ip
;
944 const struct dhcp_header
*dhcp
;
949 error
= netdev_recv(cli
->netdev
, &b
);
954 flow_extract(&b
, 0, 0, &flow
);
955 if (flow
.dl_type
!= htons(ETH_TYPE_IP
)
956 || flow
.nw_proto
!= IP_TYPE_UDP
957 || flow
.tp_dst
!= htons(DHCP_CLIENT_PORT
)
958 || !(eth_addr_is_broadcast(flow
.dl_dst
)
959 || eth_addr_equals(flow
.dl_dst
, cli_mac
))) {
964 if (IP_IS_FRAGMENT(ip
->ip_frag_off
)) {
965 /* We don't do reassembly. */
966 VLOG_WARN_RL(&rl
, "%s: ignoring fragmented DHCP datagram",
973 VLOG_WARN_RL(&rl
, "%s: ignoring DHCP datagram with missing "
974 "payload", cli_name
);
978 ofpbuf_pull(&b
, (char *)b
.l7
- (char*)b
.data
);
979 error
= dhcp_parse(msg
, &b
);
981 if (VLOG_IS_DBG_ENABLED()) {
982 VLOG_DBG_RL(&rl
, "%s: received %s", cli_name
,
983 dhcp_msg_to_string(msg
, false, &cli
->s
));
985 VLOG_INFO_RL(&rl
, "%s: received %s",
986 cli_name
, dhcp_type_name(msg
->type
));
992 netdev_drain(cli
->netdev
);
999 do_send_msg(struct dhclient
*cli
, const struct dhcp_msg
*msg
)
1001 const char *cli_name
= dhclient_get_name(cli
);
1003 struct eth_header eh
;
1004 struct ip_header nh
;
1005 struct udp_header th
;
1009 ofpbuf_init(&b
, ETH_TOTAL_MAX
);
1010 ofpbuf_reserve(&b
, ETH_HEADER_LEN
+ IP_HEADER_LEN
+ UDP_HEADER_LEN
);
1012 dhcp_assemble(msg
, &b
);
1014 netdev_get_etheraddr(cli
->netdev
, eh
.eth_src
);
1015 memcpy(eh
.eth_dst
, eth_addr_broadcast
, ETH_ADDR_LEN
);
1016 eh
.eth_type
= htons(ETH_TYPE_IP
);
1018 nh
.ip_ihl_ver
= IP_IHL_VER(5, IP_VERSION
);
1020 nh
.ip_tot_len
= htons(IP_HEADER_LEN
+ UDP_HEADER_LEN
+ b
.size
);
1021 /* We can't guarantee uniqueness of ip_id versus the host's, screwing up
1022 * fragment reassembly, so prevent fragmentation and use an all-zeros
1023 * ip_id. RFC 791 doesn't say we can do this, but Linux does the same
1024 * thing for DF packets, so it must not screw anything up. */
1026 nh
.ip_frag_off
= htons(IP_DONT_FRAGMENT
);
1028 nh
.ip_proto
= IP_TYPE_UDP
;
1030 nh
.ip_src
= dhclient_get_ip(cli
);
1031 /* XXX need to use UDP socket for nonzero server IPs so that we can get
1032 * routing table support.
1034 * if (...have server IP and in appropriate state...) {
1035 * nh.ip_dst = cli->server_ip;
1037 * nh.ip_dst = INADDR_BROADCAST;
1040 nh
.ip_dst
= INADDR_BROADCAST
;
1041 nh
.ip_csum
= csum(&nh
, sizeof nh
);
1043 th
.udp_src
= htons(DHCP_CLIENT_PORT
);
1044 th
.udp_dst
= htons(DHCP_SERVER_PORT
);
1045 th
.udp_len
= htons(UDP_HEADER_LEN
+ b
.size
);
1047 udp_csum
= csum_add32(0, nh
.ip_src
);
1048 udp_csum
= csum_add32(udp_csum
, nh
.ip_dst
);
1049 udp_csum
= csum_add16(udp_csum
, IP_TYPE_UDP
<< 8);
1050 udp_csum
= csum_add16(udp_csum
, th
.udp_len
);
1051 udp_csum
= csum_continue(udp_csum
, &th
, sizeof th
);
1052 th
.udp_csum
= csum_finish(csum_continue(udp_csum
, b
.data
, b
.size
));
1054 ofpbuf_push(&b
, &th
, sizeof th
);
1055 ofpbuf_push(&b
, &nh
, sizeof nh
);
1056 ofpbuf_push(&b
, &eh
, sizeof eh
);
1058 /* Don't try to send the frame if it's too long for an Ethernet frame. We
1059 * disregard the network device's actual MTU because we don't want the
1060 * frame to have to be discarded or fragmented if it travels over a regular
1061 * Ethernet at some point. 1500 bytes should be enough for anyone. */
1062 if (b
.size
<= ETH_TOTAL_MAX
) {
1063 if (VLOG_IS_DBG_ENABLED()) {
1064 VLOG_DBG("%s: sending %s",
1065 cli_name
, dhcp_msg_to_string(msg
, false, &cli
->s
));
1067 VLOG_INFO("%s: sending %s", cli_name
, dhcp_type_name(msg
->type
));
1069 error
= netdev_send(cli
->netdev
, &b
);
1071 VLOG_ERR("%s: send failed on %s (%s)", cli_name
,
1072 netdev_get_name(cli
->netdev
), strerror(error
));
1075 VLOG_ERR("%s: cannot send %zu-byte Ethernet frame", cli_name
, b
.size
);
1082 fuzz(unsigned int x
, int max_fuzz
)
1084 /* Generate number in range [-max_fuzz, +max_fuzz]. */
1085 int fuzz
= random_range(max_fuzz
* 2 + 1) - max_fuzz
;
1086 unsigned int y
= x
+ fuzz
;
1087 return fuzz
>= 0 ? (y
>= x
? y
: UINT_MAX
) : (y
<= x
? y
: 0);
1091 clamp(unsigned int x
, unsigned int min
, unsigned int max
)
1093 return x
< min
? min
: x
> max
? max
: x
;
1097 calc_t2(unsigned int lease
)
1099 unsigned int base
= lease
* 0.875;
1100 return lease
>= 60 ? clamp(fuzz(base
, 10), 0, lease
- 1) : base
;
1104 calc_t1(unsigned int lease
, unsigned int t2
)
1106 unsigned int base
= lease
/ 2;
1107 return lease
>= 60 ? clamp(fuzz(base
, 10), 0, t2
- 1) : base
;