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https://github.com/openvswitch/ovs
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6767a2cce9
A few common IP protocol types were defined in "lib/packets.h". However, we already assume the existence of <netinet/in.h> which contains a more exhaustive list and should be available on POSIX systems.
1109 lines
34 KiB
C
1109 lines
34 KiB
C
/*
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* Copyright (c) 2008, 2009, 2010 Nicira Networks.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <config.h>
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#include "dhcp-client.h"
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#include <arpa/inet.h>
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#include <assert.h>
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#include <errno.h>
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#include <inttypes.h>
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#include <limits.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#include <time.h>
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#include <unistd.h>
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#include "csum.h"
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#include "dhcp.h"
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#include "dynamic-string.h"
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#include "flow.h"
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#include "netdev.h"
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#include "ofpbuf.h"
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#include "poll-loop.h"
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#include "sat-math.h"
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#include "timeval.h"
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#include "vlog.h"
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VLOG_DEFINE_THIS_MODULE(dhcp_client);
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#define DHCLIENT_STATES \
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DHCLIENT_STATE(INIT, 1 << 0) \
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DHCLIENT_STATE(INIT_REBOOT, 1 << 1) \
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DHCLIENT_STATE(REBOOTING, 1 << 2) \
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DHCLIENT_STATE(SELECTING, 1 << 3) \
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DHCLIENT_STATE(REQUESTING, 1 << 4) \
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DHCLIENT_STATE(BOUND, 1 << 5) \
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DHCLIENT_STATE(RENEWING, 1 << 6) \
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DHCLIENT_STATE(REBINDING, 1 << 7) \
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DHCLIENT_STATE(RELEASED, 1 << 8)
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enum dhclient_state {
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#define DHCLIENT_STATE(NAME, VALUE) S_##NAME = VALUE,
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DHCLIENT_STATES
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#undef DHCLIENT_STATE
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};
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static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(60, 60);
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static const char *
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state_name(enum dhclient_state state)
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{
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switch (state) {
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#define DHCLIENT_STATE(NAME, VALUE) case S_##NAME: return #NAME;
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DHCLIENT_STATES
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#undef DHCLIENT_STATE
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}
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return "***ERROR***";
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}
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struct dhclient {
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/* Configuration. */
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struct netdev *netdev;
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void (*modify_request)(struct dhcp_msg *, void *aux);
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bool (*validate_offer)(const struct dhcp_msg *, void *aux);
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void *aux;
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/* DHCP state. */
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enum dhclient_state state;
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unsigned int state_entered; /* When we transitioned to this state. */
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uint32_t xid; /* In host byte order. */
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uint32_t ipaddr, netmask, router;
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uint32_t server_ip;
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struct dhcp_msg *binding;
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bool changed;
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unsigned int retransmit, delay; /* Used by send_reliably(). */
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unsigned int max_timeout;
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unsigned int init_delay; /* Used by S_INIT. */
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time_t lease_expiration;
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unsigned int bound_timeout;
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unsigned int renewing_timeout;
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unsigned int rebinding_timeout;
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/* Used by dhclient_run() and dhclient_wait() */
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unsigned int min_timeout;
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int received;
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/* Set when we send out a DHCPDISCOVER message. */
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uint32_t secs;
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struct ds s;
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};
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/* Minimum acceptable lease time, in seconds. */
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#define MIN_ACCEPTABLE_LEASE 15
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static void state_transition(struct dhclient *, enum dhclient_state);
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static unsigned int elapsed_in_this_state(const struct dhclient *cli);
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static bool timeout(struct dhclient *, unsigned int secs);
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static void dhclient_msg_init(struct dhclient *, enum dhcp_msg_type,
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struct dhcp_msg *);
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static void send_reliably(struct dhclient *cli,
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void (*make_packet)(struct dhclient *,
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struct dhcp_msg *));
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static bool do_receive_msg(struct dhclient *, struct dhcp_msg *);
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static void do_send_msg(struct dhclient *, const struct dhcp_msg *);
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static bool receive_ack(struct dhclient *);
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static unsigned int fuzz(unsigned int x, int max_fuzz);
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static unsigned int calc_t2(unsigned int lease);
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static unsigned int calc_t1(unsigned int lease, unsigned int t2);
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static unsigned int clamp(unsigned int x, unsigned int min, unsigned int max);
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/* Creates a new DHCP client to configure the network device 'netdev_name'
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* (e.g. "eth0").
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*
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* If 'modify_request' is non-null, then each DHCP message to discover or
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* request an address will be passed to it (along with auxiliary data 'aux').
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* It may then add any desired options to the message for transmission.
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*
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* If 'validate_offer' is non-null, then each DHCP message that offers an
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* address will be passed to it (along with auxiliary data 'aux') for
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* validation: if it returns true, the address will accepted; otherwise, it
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* will be rejected.
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*
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* The DHCP client will not start advertising for an IP address until
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* dhclient_init() is called.
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*
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* If successful, returns 0 and sets '*cli' to the new DHCP client. Otherwise,
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* returns a positive errno value and sets '*cli' to a null pointer. */
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int
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dhclient_create(const char *netdev_name,
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void (*modify_request)(struct dhcp_msg *, void *aux),
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bool (*validate_offer)(const struct dhcp_msg *, void *aux),
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void *aux, struct dhclient **cli_)
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{
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struct dhclient *cli;
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struct netdev_options netdev_options;
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struct netdev *netdev;
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int error;
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*cli_ = NULL;
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memset(&netdev_options, 0, sizeof netdev_options);
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netdev_options.name = netdev_name;
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netdev_options.ethertype = ETH_TYPE_IP;
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error = netdev_open(&netdev_options, &netdev);
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/* XXX install socket filter to catch only DHCP packets. */
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if (error) {
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VLOG_ERR("%s: could not open network device: %s",
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netdev_name, strerror(error));
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return error;
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}
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error = netdev_turn_flags_on(netdev, NETDEV_UP, false);
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if (error) {
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VLOG_ERR("%s: could not bring device up: %s",
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netdev_name, strerror(error));
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netdev_close(netdev);
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return error;
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}
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cli = xzalloc(sizeof *cli);
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cli->modify_request = modify_request;
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cli->validate_offer = validate_offer;
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cli->aux = aux;
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cli->netdev = netdev;
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cli->state = S_RELEASED;
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cli->state_entered = time_now();
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cli->xid = random_uint32();
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cli->ipaddr = 0;
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cli->server_ip = 0;
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cli->retransmit = cli->delay = 0;
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cli->max_timeout = 64;
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cli->min_timeout = 1;
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ds_init(&cli->s);
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cli->changed = true;
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*cli_ = cli;
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return 0;
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}
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/* Sets the maximum amount of timeout that 'cli' will wait for a reply from
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* the DHCP server before retransmitting, in seconds, to 'max_timeout'. The
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* default is 64 seconds. */
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void
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dhclient_set_max_timeout(struct dhclient *cli, unsigned int max_timeout)
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{
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cli->max_timeout = MAX(2, max_timeout);
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}
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/* Destroys 'cli' and frees all related resources. */
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void
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dhclient_destroy(struct dhclient *cli)
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{
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if (cli) {
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dhcp_msg_uninit(cli->binding);
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free(cli->binding);
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netdev_close(cli->netdev);
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ds_destroy(&cli->s);
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free(cli);
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}
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}
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/* Returns the network device in use by 'cli'. The caller must not destroy
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* the returned device. */
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struct netdev *
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dhclient_get_netdev(struct dhclient *cli)
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{
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return cli->netdev;
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}
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/* Returns the name of the network device in use by 'cli'. The caller must
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* not modify or destroy the returned string. */
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const char *
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dhclient_get_name(const struct dhclient *cli)
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{
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return netdev_get_name(cli->netdev);
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}
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/* Forces 'cli' into a (re)initialization state, in which no address is bound
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* but the client is advertising to obtain one. If 'requested_ip' is nonzero,
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* then the client will attempt to re-bind to that IP address; otherwise, it
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* will not ask for any particular address. */
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void
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dhclient_init(struct dhclient *cli, uint32_t requested_ip)
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{
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state_transition(cli, requested_ip ? S_INIT_REBOOT : S_INIT);
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cli->ipaddr = requested_ip;
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cli->min_timeout = 0;
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cli->init_delay = 0;
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}
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/* Forces 'cli' to release its bound IP address (if any). The client will not
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* advertise for a new address until dhclient_init() is called again. */
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void
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dhclient_release(struct dhclient *cli)
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{
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if (dhclient_is_bound(cli)) {
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struct dhcp_msg msg;
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dhclient_msg_init(cli, DHCPRELEASE, &msg);
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msg.ciaddr = cli->ipaddr;
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do_send_msg(cli, &msg);
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dhcp_msg_uninit(&msg);
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}
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state_transition(cli, S_RELEASED);
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cli->min_timeout = UINT_MAX;
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}
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static void
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do_force_renew(struct dhclient *cli, int deadline)
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{
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time_t now = time_now();
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unsigned int lease_left = sat_sub(cli->lease_expiration, now);
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if (lease_left <= deadline) {
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if (cli->state & (S_RENEWING | S_REBINDING)) {
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return;
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}
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deadline = lease_left;
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}
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if (cli->state & (S_BOUND | S_RENEWING)) {
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state_transition(cli, S_RENEWING);
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cli->renewing_timeout = deadline * 3 / 4;
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cli->rebinding_timeout = deadline * 1 / 4;
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} else {
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state_transition(cli, S_REBINDING);
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cli->rebinding_timeout = deadline;
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}
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cli->min_timeout = 0;
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}
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/* Forces 'cli' to attempt to renew the lease its current IP address (if any)
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* within 'deadline' seconds. If the deadline is not met, then the client
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* gives up its IP address binding and re-starts the DHCP process. */
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void
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dhclient_force_renew(struct dhclient *cli, int deadline)
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{
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/* Drain the receive queue so that we know that any DHCPACK we process is
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* freshly received. */
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netdev_drain(cli->netdev);
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switch (cli->state) {
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case S_INIT:
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case S_INIT_REBOOT:
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case S_REBOOTING:
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case S_SELECTING:
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case S_REQUESTING:
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break;
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case S_BOUND:
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case S_RENEWING:
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case S_REBINDING:
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do_force_renew(cli, deadline);
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break;
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case S_RELEASED:
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dhclient_init(cli, 0);
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break;
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}
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}
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/* Returns true if 'cli' is bound to an IP address, false otherwise. */
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bool
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dhclient_is_bound(const struct dhclient *cli)
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{
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return cli->state & (S_BOUND | S_RENEWING | S_REBINDING);
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}
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/* Returns true if 'cli' has changed from bound to unbound, or vice versa, at
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* least once since the last time this function was called. */
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bool
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dhclient_changed(struct dhclient *cli)
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{
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bool changed = cli->changed;
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cli->changed = 0;
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return changed;
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}
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/* Returns 'cli''s current state, as a string. The caller must not modify or
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* free the string. */
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const char *
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dhclient_get_state(const struct dhclient *cli)
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{
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return state_name(cli->state);
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}
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/* Returns the number of seconds spent so far in 'cli''s current state. */
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unsigned int
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dhclient_get_state_elapsed(const struct dhclient *cli)
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{
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return elapsed_in_this_state(cli);
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}
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/* If 'cli' is bound, returns the number of seconds remaining in its lease;
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* otherwise, returns 0. */
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unsigned int
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dhclient_get_lease_remaining(const struct dhclient *cli)
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{
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if (dhclient_is_bound(cli)) {
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time_t now = time_now();
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return cli->lease_expiration > now ? cli->lease_expiration - now : 0;
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} else {
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return 0;
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}
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}
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/* If 'cli' is bound to an IP address, returns that IP address; otherwise,
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* returns 0. */
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uint32_t
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dhclient_get_ip(const struct dhclient *cli)
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{
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return dhclient_is_bound(cli) ? cli->ipaddr : 0;
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}
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/* If 'cli' is bound to an IP address, returns the netmask for that IP address;
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* otherwise, returns 0. */
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uint32_t
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dhclient_get_netmask(const struct dhclient *cli)
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{
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return dhclient_is_bound(cli) ? cli->netmask : 0;
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}
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/* If 'cli' is bound to an IP address and 'cli' has a default gateway, returns
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* that default gateway; otherwise, returns 0. */
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uint32_t
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dhclient_get_router(const struct dhclient *cli)
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{
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return dhclient_is_bound(cli) ? cli->router : 0;
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}
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/* If 'cli' is bound to an IP address, returns the DHCP message that was
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* received to obtain that IP address (so that the caller can obtain additional
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* options from it). Otherwise, returns a null pointer. */
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const struct dhcp_msg *
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dhclient_get_config(const struct dhclient *cli)
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{
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return dhclient_is_bound(cli) ? cli->binding : NULL;
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}
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/* Configures the network device backing 'cli' to the network address and other
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* parameters obtained via DHCP. If no address is bound on 'cli', removes any
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* configured address from 'cli'.
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*
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* To use a dhclient as a regular DHCP client that binds and unbinds from IP
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* addresses in the usual fashion, call this function after dhclient_run() if
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* anything has changed, like so:
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*
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* dhclient_run(cli);
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* if (dhclient_changed(cli)) {
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* dhclient_configure_netdev(cli);
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* }
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*
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*/
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int
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dhclient_configure_netdev(struct dhclient *cli)
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{
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const char *cli_name = dhclient_get_name(cli);
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struct in_addr addr = { dhclient_get_ip(cli) };
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struct in_addr mask = { dhclient_get_netmask(cli) };
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struct in_addr router = { dhclient_get_router(cli) };
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int error;
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error = netdev_set_in4(cli->netdev, addr, mask);
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if (error) {
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VLOG_ERR("%s: could not set address "IP_FMT"/"IP_FMT" (%s)",
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cli_name, IP_ARGS(&addr.s_addr), IP_ARGS(&mask.s_addr),
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strerror(error));
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}
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if (!error && router.s_addr) {
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error = netdev_add_router(cli->netdev, router);
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if (error) {
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VLOG_ERR("%s: failed to add default route to "IP_FMT" (%s)",
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cli_name, IP_ARGS(&router), strerror(error));
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}
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}
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return error;
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}
|
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/* If 'cli' is bound and the binding includes DNS domain parameters, updates
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* /etc/resolv.conf will be updated to match the received parameters. Returns
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* 0 if successful, otherwise a positive errno value. */
|
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int
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dhclient_update_resolv_conf(struct dhclient *cli)
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{
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const char *cli_name = dhclient_get_name(cli);
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uint32_t dns_server;
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char *domain_name;
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bool has_domain_name;
|
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char new_name[128];
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||
FILE *old, *new;
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||
int i;
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||
|
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if (!dhclient_is_bound(cli)) {
|
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return 0;
|
||
}
|
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if (!dhcp_msg_get_ip(cli->binding, DHCP_CODE_DNS_SERVER, 0, &dns_server)) {
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VLOG_DBG("%s: binding does not include any DNS servers", cli_name);
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return 0;
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}
|
||
|
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sprintf(new_name, "/etc/resolv.conf.tmp%ld", (long int) getpid());
|
||
new = fopen(new_name, "w");
|
||
if (!new) {
|
||
VLOG_WARN("%s: could not create %s (%s)",
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cli_name, new_name, strerror(errno));
|
||
return errno;
|
||
}
|
||
|
||
domain_name = dhcp_msg_get_string(cli->binding, DHCP_CODE_DOMAIN_NAME);
|
||
has_domain_name = domain_name != NULL;
|
||
if (domain_name) {
|
||
if (strspn(domain_name, "-_.0123456789abcdefghijklmnopqrstuvwxyz"
|
||
"ABCDEFGHIJKLMNOPQRSTUVWXYZ") == strlen(domain_name)) {
|
||
fprintf(new, "domain %s\n", domain_name);
|
||
} else {
|
||
VLOG_WARN("%s: ignoring invalid domain name %s",
|
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cli_name, domain_name);
|
||
has_domain_name = false;
|
||
}
|
||
} else {
|
||
VLOG_DBG("%s: binding does not include domain name", cli_name);
|
||
}
|
||
free(domain_name);
|
||
|
||
for (i = 0; dhcp_msg_get_ip(cli->binding, DHCP_CODE_DNS_SERVER,
|
||
i, &dns_server); i++) {
|
||
fprintf(new, "nameserver "IP_FMT"\n", IP_ARGS(&dns_server));
|
||
}
|
||
|
||
old = fopen("/etc/resolv.conf", "r");
|
||
if (old) {
|
||
char line[128];
|
||
|
||
while (fgets(line, sizeof line, old)) {
|
||
char *kw = xmemdup0(line, strcspn(line, " \t\r\n"));
|
||
if (strcmp(kw, "nameserver")
|
||
&& (!has_domain_name
|
||
|| (strcmp(kw, "domain") && strcmp(kw, "search")))) {
|
||
fputs(line, new);
|
||
}
|
||
free(kw);
|
||
}
|
||
fclose(old);
|
||
} else {
|
||
VLOG_DBG("%s: failed to open /etc/resolv.conf (%s)",
|
||
cli_name, strerror(errno));
|
||
}
|
||
|
||
if (fclose(new) < 0) {
|
||
VLOG_WARN("%s: closing %s failed (%s)",
|
||
cli_name, new_name, strerror(errno));
|
||
return errno;
|
||
}
|
||
|
||
if (rename(new_name, "/etc/resolv.conf") < 0) {
|
||
VLOG_WARN("%s: failed to rename %s to /etc/resolv.conf (%s)",
|
||
cli_name, new_name, strerror(errno));
|
||
return errno;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* DHCP protocol. */
|
||
|
||
static void
|
||
make_dhcpdiscover(struct dhclient *cli, struct dhcp_msg *msg)
|
||
{
|
||
cli->secs = elapsed_in_this_state(cli);
|
||
dhclient_msg_init(cli, DHCPDISCOVER, msg);
|
||
if (cli->ipaddr) {
|
||
dhcp_msg_put_ip(msg, DHCP_CODE_REQUESTED_IP, cli->ipaddr);
|
||
}
|
||
}
|
||
|
||
static void
|
||
make_dhcprequest(struct dhclient *cli, struct dhcp_msg *msg)
|
||
{
|
||
dhclient_msg_init(cli, DHCPREQUEST, msg);
|
||
msg->ciaddr = dhclient_get_ip(cli);
|
||
if (cli->state == S_REQUESTING) {
|
||
dhcp_msg_put_ip(msg, DHCP_CODE_SERVER_IDENTIFIER, cli->server_ip);
|
||
}
|
||
dhcp_msg_put_ip(msg, DHCP_CODE_REQUESTED_IP, cli->ipaddr);
|
||
}
|
||
|
||
static void
|
||
do_init(struct dhclient *cli, enum dhclient_state next_state)
|
||
{
|
||
if (!cli->init_delay) {
|
||
cli->init_delay = fuzz(2, 1);
|
||
}
|
||
if (timeout(cli, cli->init_delay)) {
|
||
state_transition(cli, next_state);
|
||
}
|
||
}
|
||
|
||
static void
|
||
dhclient_run_INIT(struct dhclient *cli)
|
||
{
|
||
do_init(cli, S_SELECTING);
|
||
}
|
||
|
||
static void
|
||
dhclient_run_INIT_REBOOT(struct dhclient *cli)
|
||
{
|
||
do_init(cli, S_REBOOTING);
|
||
}
|
||
|
||
static void
|
||
dhclient_run_REBOOTING(struct dhclient *cli)
|
||
{
|
||
send_reliably(cli, make_dhcprequest);
|
||
if (!receive_ack(cli) && timeout(cli, 60)) {
|
||
state_transition(cli, S_INIT);
|
||
}
|
||
}
|
||
|
||
static bool
|
||
dhcp_receive(struct dhclient *cli, unsigned int msgs, struct dhcp_msg *msg)
|
||
{
|
||
while (do_receive_msg(cli, msg)) {
|
||
const char *cli_name = dhclient_get_name(cli);
|
||
|
||
if (msg->type > 31 || !((1u << msg->type) & msgs)) {
|
||
VLOG_DBG_RL(&rl, "%s: received unexpected %s in %s state: %s",
|
||
cli_name,
|
||
dhcp_type_name(msg->type), state_name(cli->state),
|
||
dhcp_msg_to_string(msg, false, &cli->s));
|
||
} else if (msg->xid != cli->xid) {
|
||
VLOG_DBG_RL(&rl, "%s: ignoring %s with xid != %08"PRIx32" "
|
||
"in %s state: %s", cli_name,
|
||
dhcp_type_name(msg->type), msg->xid,
|
||
state_name(cli->state),
|
||
dhcp_msg_to_string(msg, false, &cli->s));
|
||
} else {
|
||
return true;
|
||
}
|
||
dhcp_msg_uninit(msg);
|
||
}
|
||
return false;
|
||
}
|
||
|
||
static bool
|
||
validate_offered_options(struct dhclient *cli, const struct dhcp_msg *msg)
|
||
{
|
||
const char *cli_name = dhclient_get_name(cli);
|
||
uint32_t lease, netmask;
|
||
|
||
if (!dhcp_msg_get_secs(msg, DHCP_CODE_LEASE_TIME, 0, &lease)) {
|
||
VLOG_WARN_RL(&rl, "%s: %s lacks lease time (%s)",
|
||
cli_name, dhcp_type_name(msg->type),
|
||
dhcp_msg_to_string(msg, false, &cli->s));
|
||
} else if (!dhcp_msg_get_ip(msg, DHCP_CODE_SUBNET_MASK, 0, &netmask)) {
|
||
VLOG_WARN_RL(&rl, "%s: %s lacks netmask (%s)",
|
||
cli_name, dhcp_type_name(msg->type),
|
||
dhcp_msg_to_string(msg, false, &cli->s));
|
||
} else if (lease < MIN_ACCEPTABLE_LEASE) {
|
||
VLOG_WARN_RL(&rl, "%s: ignoring %s with %"PRIu32"-second "
|
||
"lease time (%s)", cli_name,
|
||
dhcp_type_name(msg->type), lease,
|
||
dhcp_msg_to_string(msg, false, &cli->s));
|
||
} else if (cli->validate_offer && !cli->validate_offer(msg, cli->aux)) {
|
||
VLOG_DBG_RL(&rl, "%s: client validation hook refused offer (%s)",
|
||
cli_name, dhcp_msg_to_string(msg, false, &cli->s));
|
||
} else {
|
||
return true;
|
||
}
|
||
return false;
|
||
}
|
||
|
||
static void
|
||
dhclient_run_SELECTING(struct dhclient *cli)
|
||
{
|
||
const char *cli_name = dhclient_get_name(cli);
|
||
struct dhcp_msg msg;
|
||
|
||
send_reliably(cli, make_dhcpdiscover);
|
||
if (cli->server_ip && timeout(cli, 60)) {
|
||
cli->server_ip = 0;
|
||
state_transition(cli, S_INIT);
|
||
}
|
||
for (; dhcp_receive(cli, 1u << DHCPOFFER, &msg); dhcp_msg_uninit(&msg)) {
|
||
if (!validate_offered_options(cli, &msg)) {
|
||
continue;
|
||
}
|
||
if (!dhcp_msg_get_ip(&msg, DHCP_CODE_SERVER_IDENTIFIER,
|
||
0, &cli->server_ip)) {
|
||
VLOG_WARN_RL(&rl, "%s: DHCPOFFER lacks server identifier (%s)",
|
||
cli_name, dhcp_msg_to_string(&msg, false, &cli->s));
|
||
continue;
|
||
}
|
||
|
||
VLOG_DBG_RL(&rl, "%s: accepting DHCPOFFER (%s)",
|
||
cli_name, dhcp_msg_to_string(&msg, false, &cli->s));
|
||
cli->ipaddr = msg.yiaddr;
|
||
state_transition(cli, S_REQUESTING);
|
||
break;
|
||
}
|
||
}
|
||
|
||
static bool
|
||
same_binding(const char *cli_name,
|
||
const struct dhcp_msg *old, const struct dhcp_msg *new)
|
||
{
|
||
static const int codes[] = {
|
||
DHCP_CODE_SUBNET_MASK,
|
||
DHCP_CODE_ROUTER,
|
||
DHCP_CODE_DNS_SERVER,
|
||
DHCP_CODE_HOST_NAME,
|
||
DHCP_CODE_DOMAIN_NAME,
|
||
DHCP_CODE_IP_TTL,
|
||
DHCP_CODE_MTU,
|
||
DHCP_CODE_BROADCAST_ADDRESS,
|
||
DHCP_CODE_STATIC_ROUTE,
|
||
DHCP_CODE_ARP_CACHE_TIMEOUT,
|
||
DHCP_CODE_ETHERNET_ENCAPSULATION,
|
||
DHCP_CODE_TCP_TTL,
|
||
DHCP_CODE_SERVER_IDENTIFIER,
|
||
DHCP_CODE_OFP_CONTROLLER_VCONN,
|
||
DHCP_CODE_OFP_PKI_URI,
|
||
};
|
||
int i;
|
||
bool same = true;
|
||
|
||
if (old->yiaddr != new->yiaddr) {
|
||
VLOG_WARN("%s: DHCP binding changed IP address "
|
||
"from "IP_FMT" to "IP_FMT,
|
||
cli_name, IP_ARGS(&old->yiaddr), IP_ARGS(&new->yiaddr));
|
||
same = false;
|
||
}
|
||
for (i = 0; i < ARRAY_SIZE(codes); i++) {
|
||
int code = codes[i];
|
||
const struct dhcp_option *old_opt = &old->options[code];
|
||
const struct dhcp_option *new_opt = &new->options[code];
|
||
if (!dhcp_option_equals(old_opt, new_opt)) {
|
||
struct ds old_string = DS_EMPTY_INITIALIZER;
|
||
struct ds new_string = DS_EMPTY_INITIALIZER;
|
||
VLOG_WARN("%s: DHCP binding changed option from %s to %s",
|
||
cli_name,
|
||
dhcp_option_to_string(old_opt, code, &old_string),
|
||
dhcp_option_to_string(new_opt, code, &new_string));
|
||
ds_destroy(&old_string);
|
||
ds_destroy(&new_string);
|
||
same = false;
|
||
}
|
||
}
|
||
return same;
|
||
}
|
||
|
||
static bool
|
||
receive_ack(struct dhclient *cli)
|
||
{
|
||
struct dhcp_msg msg;
|
||
|
||
if (!dhcp_receive(cli, (1u << DHCPACK) | (1u << DHCPNAK), &msg)) {
|
||
return false;
|
||
} else if (msg.type == DHCPNAK) {
|
||
dhcp_msg_uninit(&msg);
|
||
state_transition(cli, S_INIT);
|
||
return true;
|
||
} else if (!validate_offered_options(cli, &msg)) {
|
||
dhcp_msg_uninit(&msg);
|
||
return false;
|
||
} else {
|
||
uint32_t lease = 0, t1 = 0, t2 = 0;
|
||
|
||
if (cli->binding) {
|
||
if (!same_binding(dhclient_get_name(cli), cli->binding, &msg)) {
|
||
cli->changed = true;
|
||
}
|
||
dhcp_msg_uninit(cli->binding);
|
||
} else {
|
||
cli->binding = xmalloc(sizeof *cli->binding);
|
||
}
|
||
dhcp_msg_copy(cli->binding, &msg);
|
||
|
||
dhcp_msg_get_secs(&msg, DHCP_CODE_LEASE_TIME, 0, &lease);
|
||
dhcp_msg_get_secs(&msg, DHCP_CODE_T1, 0, &t1);
|
||
dhcp_msg_get_secs(&msg, DHCP_CODE_T2, 0, &t2);
|
||
assert(lease >= MIN_ACCEPTABLE_LEASE);
|
||
|
||
if (!t2 || t2 >= lease) {
|
||
t2 = calc_t2(lease);
|
||
}
|
||
if (!t1 || t1 >= t2) {
|
||
t1 = calc_t1(lease, t2);
|
||
}
|
||
|
||
cli->lease_expiration = sat_add(time_now(), lease);
|
||
cli->bound_timeout = t1;
|
||
cli->renewing_timeout = t2 - t1;
|
||
cli->rebinding_timeout = lease - t2;
|
||
|
||
cli->ipaddr = msg.yiaddr;
|
||
dhcp_msg_get_ip(&msg, DHCP_CODE_SUBNET_MASK, 0, &cli->netmask);
|
||
if (!dhcp_msg_get_ip(&msg, DHCP_CODE_ROUTER, 0, &cli->router)) {
|
||
cli->router = INADDR_ANY;
|
||
}
|
||
state_transition(cli, S_BOUND);
|
||
VLOG_DBG("%s: bound (%s)", dhclient_get_name(cli),
|
||
dhcp_msg_to_string(&msg, false, &cli->s));
|
||
return true;
|
||
}
|
||
}
|
||
|
||
static void
|
||
dhclient_run_REQUESTING(struct dhclient *cli)
|
||
{
|
||
send_reliably(cli, make_dhcprequest);
|
||
if (!receive_ack(cli) && timeout(cli, 60)) {
|
||
state_transition(cli, S_INIT);
|
||
}
|
||
}
|
||
|
||
static void
|
||
dhclient_run_BOUND(struct dhclient *cli)
|
||
{
|
||
if (timeout(cli, cli->bound_timeout)) {
|
||
state_transition(cli, S_RENEWING);
|
||
}
|
||
}
|
||
|
||
static void
|
||
dhclient_run_RENEWING(struct dhclient *cli)
|
||
{
|
||
send_reliably(cli, make_dhcprequest);
|
||
if (!receive_ack(cli) && timeout(cli, cli->renewing_timeout)) {
|
||
state_transition(cli, S_REBINDING);
|
||
}
|
||
}
|
||
|
||
static void
|
||
dhclient_run_REBINDING(struct dhclient *cli)
|
||
{
|
||
send_reliably(cli, make_dhcprequest);
|
||
if (!receive_ack(cli) && timeout(cli, cli->rebinding_timeout)) {
|
||
state_transition(cli, S_INIT);
|
||
}
|
||
}
|
||
|
||
static void
|
||
dhclient_run_RELEASED(struct dhclient *cli OVS_UNUSED)
|
||
{
|
||
/* Nothing to do. */
|
||
}
|
||
|
||
/* Processes the DHCP protocol for 'cli'. */
|
||
void
|
||
dhclient_run(struct dhclient *cli)
|
||
{
|
||
int old_state;
|
||
do {
|
||
old_state = cli->state;
|
||
cli->min_timeout = UINT_MAX;
|
||
cli->received = 0;
|
||
switch (cli->state) {
|
||
#define DHCLIENT_STATE(NAME, VALUE) \
|
||
case S_##NAME: dhclient_run_##NAME(cli); break;
|
||
DHCLIENT_STATES
|
||
#undef DHCLIENT_STATE
|
||
default:
|
||
NOT_REACHED();
|
||
}
|
||
} while (cli->state != old_state);
|
||
}
|
||
|
||
/* Sets up poll timeouts to wake up the poll loop when 'cli' needs to do some
|
||
* work. */
|
||
void
|
||
dhclient_wait(struct dhclient *cli)
|
||
{
|
||
if (cli->min_timeout != UINT_MAX) {
|
||
long long int wake = sat_add(cli->state_entered, cli->min_timeout);
|
||
poll_timer_wait_until(wake * 1000);
|
||
}
|
||
/* Reset timeout to 1 second. This will have no effect ordinarily, because
|
||
* dhclient_run() will typically set it back to a higher value. If,
|
||
* however, the caller fails to call dhclient_run() before its next call to
|
||
* dhclient_wait() we won't potentially block forever. */
|
||
cli->min_timeout = 1;
|
||
|
||
if (cli->state & (S_SELECTING | S_REQUESTING | S_RENEWING | S_REBINDING)) {
|
||
netdev_recv_wait(cli->netdev);
|
||
}
|
||
}
|
||
|
||
static void
|
||
state_transition(struct dhclient *cli, enum dhclient_state state)
|
||
{
|
||
const char *cli_name = dhclient_get_name(cli);
|
||
bool was_bound = dhclient_is_bound(cli);
|
||
bool am_bound;
|
||
|
||
if (cli->state != state) {
|
||
VLOG_DBG("%s: entering %s", cli_name, state_name(state));
|
||
cli->state = state;
|
||
}
|
||
cli->state_entered = time_now();
|
||
cli->retransmit = cli->delay = 0;
|
||
am_bound = dhclient_is_bound(cli);
|
||
if (was_bound != am_bound) {
|
||
cli->changed = true;
|
||
if (am_bound) {
|
||
assert(cli->binding != NULL);
|
||
VLOG_INFO("%s: obtained address "IP_FMT", netmask "IP_FMT,
|
||
cli_name,
|
||
IP_ARGS(&cli->ipaddr), IP_ARGS(&cli->netmask));
|
||
if (cli->router) {
|
||
VLOG_INFO("%s: obtained default gateway "IP_FMT,
|
||
cli_name, IP_ARGS(&cli->router));
|
||
}
|
||
} else {
|
||
dhcp_msg_uninit(cli->binding);
|
||
free(cli->binding);
|
||
cli->binding = NULL;
|
||
|
||
VLOG_INFO("%s: network address unbound", cli_name);
|
||
}
|
||
}
|
||
if (cli->state & (S_SELECTING | S_REQUESTING | S_REBOOTING)) {
|
||
netdev_drain(cli->netdev);
|
||
}
|
||
}
|
||
|
||
static void
|
||
send_reliably(struct dhclient *cli,
|
||
void (*make_packet)(struct dhclient *, struct dhcp_msg *))
|
||
{
|
||
if (timeout(cli, cli->retransmit)) {
|
||
struct dhcp_msg msg;
|
||
make_packet(cli, &msg);
|
||
if (cli->modify_request) {
|
||
cli->modify_request(&msg, cli->aux);
|
||
}
|
||
do_send_msg(cli, &msg);
|
||
cli->delay = MIN(cli->max_timeout, MAX(4, cli->delay * 2));
|
||
cli->retransmit += fuzz(cli->delay, 1);
|
||
timeout(cli, cli->retransmit);
|
||
dhcp_msg_uninit(&msg);
|
||
}
|
||
}
|
||
|
||
static void
|
||
dhclient_msg_init(struct dhclient *cli, enum dhcp_msg_type type,
|
||
struct dhcp_msg *msg)
|
||
{
|
||
dhcp_msg_init(msg);
|
||
msg->op = DHCP_BOOTREQUEST;
|
||
msg->xid = cli->xid;
|
||
msg->secs = cli->secs;
|
||
msg->type = type;
|
||
netdev_get_etheraddr(cli->netdev, msg->chaddr);
|
||
}
|
||
|
||
/* If time goes backward this returns a large number, which makes it look like
|
||
* we've been in the current state a very long time. That's probably
|
||
* fine for that corner case--we'll just expire our lease, etc., and try to
|
||
* get a new one. */
|
||
static unsigned int
|
||
elapsed_in_this_state(const struct dhclient *cli)
|
||
{
|
||
return time_now() - cli->state_entered;
|
||
}
|
||
|
||
static bool
|
||
timeout(struct dhclient *cli, unsigned int secs)
|
||
{
|
||
cli->min_timeout = MIN(cli->min_timeout, secs);
|
||
return time_now() >= sat_add(cli->state_entered, secs);
|
||
}
|
||
|
||
static bool
|
||
do_receive_msg(struct dhclient *cli, struct dhcp_msg *msg)
|
||
{
|
||
const char *cli_name = dhclient_get_name(cli);
|
||
uint8_t cli_mac[ETH_ADDR_LEN];
|
||
struct ofpbuf b;
|
||
int mtu;
|
||
|
||
netdev_get_mtu(cli->netdev, &mtu);
|
||
ofpbuf_init(&b, mtu + VLAN_ETH_HEADER_LEN);
|
||
netdev_get_etheraddr(cli->netdev, cli_mac);
|
||
for (; cli->received < 50; cli->received++) {
|
||
const struct ip_header *ip;
|
||
const struct dhcp_header *dhcp;
|
||
struct flow flow;
|
||
int error;
|
||
|
||
ofpbuf_clear(&b);
|
||
error = netdev_recv(cli->netdev, &b);
|
||
if (error) {
|
||
goto drained;
|
||
}
|
||
|
||
flow_extract(&b, 0, 0, &flow);
|
||
if (flow.dl_type != htons(ETH_TYPE_IP)
|
||
|| flow.nw_proto != IPPROTO_UDP
|
||
|| flow.tp_dst != htons(DHCP_CLIENT_PORT)
|
||
|| !(eth_addr_is_broadcast(flow.dl_dst)
|
||
|| eth_addr_equals(flow.dl_dst, cli_mac))) {
|
||
continue;
|
||
}
|
||
|
||
ip = b.l3;
|
||
if (IP_IS_FRAGMENT(ip->ip_frag_off)) {
|
||
/* We don't do reassembly. */
|
||
VLOG_WARN_RL(&rl, "%s: ignoring fragmented DHCP datagram",
|
||
cli_name);
|
||
continue;
|
||
}
|
||
|
||
dhcp = b.l7;
|
||
if (!dhcp) {
|
||
VLOG_WARN_RL(&rl, "%s: ignoring DHCP datagram with missing "
|
||
"payload", cli_name);
|
||
continue;
|
||
}
|
||
|
||
ofpbuf_pull(&b, (char *)b.l7 - (char*)b.data);
|
||
error = dhcp_parse(msg, &b);
|
||
if (!error) {
|
||
if (VLOG_IS_DBG_ENABLED()) {
|
||
VLOG_DBG_RL(&rl, "%s: received %s", cli_name,
|
||
dhcp_msg_to_string(msg, false, &cli->s));
|
||
} else {
|
||
VLOG_INFO_RL(&rl, "%s: received %s",
|
||
cli_name, dhcp_type_name(msg->type));
|
||
}
|
||
ofpbuf_uninit(&b);
|
||
return true;
|
||
}
|
||
}
|
||
netdev_drain(cli->netdev);
|
||
drained:
|
||
ofpbuf_uninit(&b);
|
||
return false;
|
||
}
|
||
|
||
static void
|
||
do_send_msg(struct dhclient *cli, const struct dhcp_msg *msg)
|
||
{
|
||
const char *cli_name = dhclient_get_name(cli);
|
||
struct ofpbuf b;
|
||
struct eth_header eh;
|
||
struct ip_header nh;
|
||
struct udp_header th;
|
||
uint32_t udp_csum;
|
||
int error;
|
||
|
||
ofpbuf_init(&b, ETH_TOTAL_MAX);
|
||
ofpbuf_reserve(&b, ETH_HEADER_LEN + IP_HEADER_LEN + UDP_HEADER_LEN);
|
||
|
||
dhcp_assemble(msg, &b);
|
||
|
||
netdev_get_etheraddr(cli->netdev, eh.eth_src);
|
||
memcpy(eh.eth_dst, eth_addr_broadcast, ETH_ADDR_LEN);
|
||
eh.eth_type = htons(ETH_TYPE_IP);
|
||
|
||
nh.ip_ihl_ver = IP_IHL_VER(5, IP_VERSION);
|
||
nh.ip_tos = 0;
|
||
nh.ip_tot_len = htons(IP_HEADER_LEN + UDP_HEADER_LEN + b.size);
|
||
/* We can't guarantee uniqueness of ip_id versus the host's, screwing up
|
||
* fragment reassembly, so prevent fragmentation and use an all-zeros
|
||
* ip_id. RFC 791 doesn't say we can do this, but Linux does the same
|
||
* thing for DF packets, so it must not screw anything up. */
|
||
nh.ip_id = 0;
|
||
nh.ip_frag_off = htons(IP_DONT_FRAGMENT);
|
||
nh.ip_ttl = 64;
|
||
nh.ip_proto = IPPROTO_UDP;
|
||
nh.ip_csum = 0;
|
||
nh.ip_src = dhclient_get_ip(cli);
|
||
/* XXX need to use UDP socket for nonzero server IPs so that we can get
|
||
* routing table support.
|
||
*
|
||
* if (...have server IP and in appropriate state...) {
|
||
* nh.ip_dst = cli->server_ip;
|
||
* } else {
|
||
* nh.ip_dst = INADDR_BROADCAST;
|
||
* }
|
||
*/
|
||
nh.ip_dst = INADDR_BROADCAST;
|
||
nh.ip_csum = csum(&nh, sizeof nh);
|
||
|
||
th.udp_src = htons(DHCP_CLIENT_PORT);
|
||
th.udp_dst = htons(DHCP_SERVER_PORT);
|
||
th.udp_len = htons(UDP_HEADER_LEN + b.size);
|
||
th.udp_csum = 0;
|
||
udp_csum = csum_add32(0, nh.ip_src);
|
||
udp_csum = csum_add32(udp_csum, nh.ip_dst);
|
||
udp_csum = csum_add16(udp_csum, IPPROTO_UDP << 8);
|
||
udp_csum = csum_add16(udp_csum, th.udp_len);
|
||
udp_csum = csum_continue(udp_csum, &th, sizeof th);
|
||
th.udp_csum = csum_finish(csum_continue(udp_csum, b.data, b.size));
|
||
|
||
ofpbuf_push(&b, &th, sizeof th);
|
||
ofpbuf_push(&b, &nh, sizeof nh);
|
||
ofpbuf_push(&b, &eh, sizeof eh);
|
||
|
||
/* Don't try to send the frame if it's too long for an Ethernet frame. We
|
||
* disregard the network device's actual MTU because we don't want the
|
||
* frame to have to be discarded or fragmented if it travels over a regular
|
||
* Ethernet at some point. 1500 bytes should be enough for anyone. */
|
||
if (b.size <= ETH_TOTAL_MAX) {
|
||
if (VLOG_IS_DBG_ENABLED()) {
|
||
VLOG_DBG("%s: sending %s",
|
||
cli_name, dhcp_msg_to_string(msg, false, &cli->s));
|
||
} else {
|
||
VLOG_INFO("%s: sending %s", cli_name, dhcp_type_name(msg->type));
|
||
}
|
||
error = netdev_send(cli->netdev, &b);
|
||
if (error) {
|
||
VLOG_ERR("%s: send failed on %s (%s)", cli_name,
|
||
netdev_get_name(cli->netdev), strerror(error));
|
||
}
|
||
} else {
|
||
VLOG_ERR("%s: cannot send %zu-byte Ethernet frame", cli_name, b.size);
|
||
}
|
||
|
||
ofpbuf_uninit(&b);
|
||
}
|
||
|
||
static unsigned int
|
||
fuzz(unsigned int x, int max_fuzz)
|
||
{
|
||
/* Generate number in range [-max_fuzz, +max_fuzz]. */
|
||
int fuzz = random_range(max_fuzz * 2 + 1) - max_fuzz;
|
||
unsigned int y = x + fuzz;
|
||
return fuzz >= 0 ? (y >= x ? y : UINT_MAX) : (y <= x ? y : 0);
|
||
}
|
||
|
||
static unsigned int
|
||
clamp(unsigned int x, unsigned int min, unsigned int max)
|
||
{
|
||
return x < min ? min : x > max ? max : x;
|
||
}
|
||
|
||
static unsigned int
|
||
calc_t2(unsigned int lease)
|
||
{
|
||
unsigned int base = lease * 0.875;
|
||
return lease >= 60 ? clamp(fuzz(base, 10), 0, lease - 1) : base;
|
||
}
|
||
|
||
static unsigned int
|
||
calc_t1(unsigned int lease, unsigned int t2)
|
||
{
|
||
unsigned int base = lease / 2;
|
||
return lease >= 60 ? clamp(fuzz(base, 10), 0, t2 - 1) : base;
|
||
}
|