1263 lines
35 KiB
C
1263 lines
35 KiB
C
/***
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This file is part of systemd.
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Copyright (C) 2013 Intel Corporation. All rights reserved.
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <stdlib.h>
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#include <errno.h>
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#include <string.h>
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#include <stdio.h>
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#include <net/ethernet.h>
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#include <sys/param.h>
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#include "util.h"
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#include "list.h"
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#include "dhcp-protocol.h"
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#include "dhcp-internal.h"
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#include "sd-dhcp-client.h"
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#define DHCP_CLIENT_MIN_OPTIONS_SIZE 312
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struct DHCPLease {
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uint32_t t1;
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uint32_t t2;
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uint32_t lifetime;
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be32_t address;
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be32_t server_address;
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be32_t subnet_mask;
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be32_t router;
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struct in_addr **dns;
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uint16_t mtu;
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char *hostname;
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};
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typedef struct DHCPLease DHCPLease;
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struct sd_dhcp_client {
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DHCPState state;
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sd_event *event;
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sd_event_source *timeout_resend;
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int index;
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int fd;
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union sockaddr_union link;
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sd_event_source *receive_message;
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uint8_t *req_opts;
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size_t req_opts_allocated;
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size_t req_opts_size;
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be32_t last_addr;
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struct ether_addr mac_addr;
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uint32_t xid;
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usec_t start_time;
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unsigned int attempt;
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usec_t request_sent;
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sd_event_source *timeout_t1;
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sd_event_source *timeout_t2;
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sd_event_source *timeout_expire;
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sd_dhcp_client_cb_t cb;
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void *userdata;
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DHCPLease *lease;
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};
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static const uint8_t default_req_opts[] = {
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DHCP_OPTION_SUBNET_MASK,
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DHCP_OPTION_ROUTER,
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DHCP_OPTION_HOST_NAME,
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DHCP_OPTION_DOMAIN_NAME,
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DHCP_OPTION_DOMAIN_NAME_SERVER,
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DHCP_OPTION_NTP_SERVER,
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};
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static int client_receive_message(sd_event_source *s, int fd,
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uint32_t revents, void *userdata);
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int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb,
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void *userdata)
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{
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assert_return(client, -EINVAL);
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client->cb = cb;
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client->userdata = userdata;
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return 0;
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}
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int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option)
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{
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size_t i;
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assert_return(client, -EINVAL);
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assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
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switch(option) {
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case DHCP_OPTION_PAD:
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case DHCP_OPTION_OVERLOAD:
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case DHCP_OPTION_MESSAGE_TYPE:
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case DHCP_OPTION_PARAMETER_REQUEST_LIST:
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case DHCP_OPTION_END:
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return -EINVAL;
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default:
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break;
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}
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for (i = 0; i < client->req_opts_size; i++)
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if (client->req_opts[i] == option)
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return -EEXIST;
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if (!GREEDY_REALLOC(client->req_opts, client->req_opts_allocated,
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client->req_opts_size + 1))
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return -ENOMEM;
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client->req_opts[client->req_opts_size++] = option;
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return 0;
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}
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int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
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const struct in_addr *last_addr)
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{
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assert_return(client, -EINVAL);
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assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
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if (last_addr)
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client->last_addr = last_addr->s_addr;
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else
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client->last_addr = INADDR_ANY;
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return 0;
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}
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int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index)
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{
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assert_return(client, -EINVAL);
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assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
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assert_return(interface_index >= -1, -EINVAL);
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client->index = interface_index;
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return 0;
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}
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int sd_dhcp_client_set_mac(sd_dhcp_client *client,
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const struct ether_addr *addr)
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{
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assert_return(client, -EINVAL);
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assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
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memcpy(&client->mac_addr, addr, ETH_ALEN);
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return 0;
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}
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int sd_dhcp_client_get_address(sd_dhcp_client *client, struct in_addr *addr)
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{
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assert_return(client, -EINVAL);
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assert_return(addr, -EINVAL);
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switch (client->state) {
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case DHCP_STATE_INIT:
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case DHCP_STATE_SELECTING:
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case DHCP_STATE_INIT_REBOOT:
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case DHCP_STATE_REBOOTING:
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case DHCP_STATE_REQUESTING:
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return -EADDRNOTAVAIL;
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case DHCP_STATE_BOUND:
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case DHCP_STATE_RENEWING:
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case DHCP_STATE_REBINDING:
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addr->s_addr = client->lease->address;
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break;
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}
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return 0;
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}
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int sd_dhcp_client_get_mtu(sd_dhcp_client *client, uint16_t *mtu)
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{
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assert_return(client, -EINVAL);
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assert_return(mtu, -EINVAL);
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switch (client->state) {
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case DHCP_STATE_INIT:
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case DHCP_STATE_SELECTING:
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case DHCP_STATE_INIT_REBOOT:
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case DHCP_STATE_REBOOTING:
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case DHCP_STATE_REQUESTING:
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return -EADDRNOTAVAIL;
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case DHCP_STATE_BOUND:
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case DHCP_STATE_RENEWING:
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case DHCP_STATE_REBINDING:
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if (client->lease->mtu)
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*mtu = client->lease->mtu;
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else
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return -ENOENT;
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break;
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}
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return 0;
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}
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int sd_dhcp_client_get_dns(sd_dhcp_client *client, struct in_addr ***addr)
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{
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assert_return(client, -EINVAL);
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assert_return(addr, -EINVAL);
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switch (client->state) {
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case DHCP_STATE_INIT:
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case DHCP_STATE_SELECTING:
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case DHCP_STATE_INIT_REBOOT:
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case DHCP_STATE_REBOOTING:
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case DHCP_STATE_REQUESTING:
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return -EADDRNOTAVAIL;
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case DHCP_STATE_BOUND:
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case DHCP_STATE_RENEWING:
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case DHCP_STATE_REBINDING:
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if (client->lease->dns)
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*addr = client->lease->dns;
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else
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return -ENOENT;
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break;
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}
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return 0;
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}
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int sd_dhcp_client_get_hostname(sd_dhcp_client *client, const char **hostname)
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{
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assert_return(client, -EINVAL);
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assert_return(hostname, -EINVAL);
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switch (client->state) {
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case DHCP_STATE_INIT:
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case DHCP_STATE_SELECTING:
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case DHCP_STATE_INIT_REBOOT:
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case DHCP_STATE_REBOOTING:
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case DHCP_STATE_REQUESTING:
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return -EADDRNOTAVAIL;
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case DHCP_STATE_BOUND:
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case DHCP_STATE_RENEWING:
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case DHCP_STATE_REBINDING:
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if (client->lease->hostname)
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*hostname = client->lease->hostname;
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else
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return -ENOENT;
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break;
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}
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return 0;
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}
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int sd_dhcp_client_prefixlen(const struct in_addr *addr)
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{
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int len = 0;
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uint32_t mask;
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assert_return(addr, -EADDRNOTAVAIL);
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mask = be32toh(addr->s_addr);
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while (mask) {
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len++;
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mask = mask << 1;
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}
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return len;
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}
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int sd_dhcp_client_get_router(sd_dhcp_client *client, struct in_addr *addr)
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{
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assert_return(client, -EINVAL);
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assert_return(addr, -EINVAL);
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switch (client->state) {
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case DHCP_STATE_INIT:
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case DHCP_STATE_SELECTING:
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case DHCP_STATE_INIT_REBOOT:
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case DHCP_STATE_REBOOTING:
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case DHCP_STATE_REQUESTING:
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return -EADDRNOTAVAIL;
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case DHCP_STATE_BOUND:
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case DHCP_STATE_RENEWING:
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case DHCP_STATE_REBINDING:
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addr->s_addr = client->lease->router;
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break;
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}
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return 0;
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}
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int sd_dhcp_client_get_netmask(sd_dhcp_client *client, struct in_addr *addr)
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{
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assert_return(client, -EINVAL);
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assert_return(addr, -EINVAL);
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switch (client->state) {
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case DHCP_STATE_INIT:
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case DHCP_STATE_SELECTING:
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case DHCP_STATE_INIT_REBOOT:
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case DHCP_STATE_REBOOTING:
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case DHCP_STATE_REQUESTING:
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return -EADDRNOTAVAIL;
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case DHCP_STATE_BOUND:
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case DHCP_STATE_RENEWING:
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case DHCP_STATE_REBINDING:
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addr->s_addr = client->lease->subnet_mask;
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break;
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}
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return 0;
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}
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static int client_notify(sd_dhcp_client *client, int event)
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{
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if (client->cb)
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client->cb(client, event, client->userdata);
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return 0;
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}
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static void in_addrs_free(struct in_addr **addrs) {
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unsigned i;
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if (!addrs)
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return;
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for (i = 0; addrs[i]; i++)
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free(addrs[i]);
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free(addrs);
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}
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static int client_stop(sd_dhcp_client *client, int error)
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{
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assert_return(client, -EINVAL);
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client->receive_message =
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sd_event_source_unref(client->receive_message);
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if (client->fd >= 0)
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close(client->fd);
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client->fd = -1;
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client->timeout_resend = sd_event_source_unref(client->timeout_resend);
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client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
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client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
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client->timeout_expire = sd_event_source_unref(client->timeout_expire);
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client->attempt = 1;
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client_notify(client, error);
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switch (client->state) {
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case DHCP_STATE_INIT:
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case DHCP_STATE_SELECTING:
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case DHCP_STATE_REQUESTING:
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case DHCP_STATE_BOUND:
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client->start_time = 0;
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client->state = DHCP_STATE_INIT;
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break;
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case DHCP_STATE_INIT_REBOOT:
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case DHCP_STATE_REBOOTING:
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case DHCP_STATE_RENEWING:
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case DHCP_STATE_REBINDING:
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break;
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}
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if (client->lease) {
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in_addrs_free(client->lease->dns);
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free(client->lease);
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client->lease = NULL;
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}
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return 0;
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}
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static int client_packet_init(sd_dhcp_client *client, uint8_t type,
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DHCPMessage *message, uint16_t secs,
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uint8_t **opt, size_t *optlen)
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{
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int err;
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be16_t max_size;
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*opt = (uint8_t *)(message + 1);
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if (*optlen < 4)
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return -ENOBUFS;
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*optlen -= 4;
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message->op = BOOTREQUEST;
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message->htype = 1;
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message->hlen = ETHER_ADDR_LEN;
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message->xid = htobe32(client->xid);
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/* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
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refuse to issue an DHCP lease if 'secs' is set to zero */
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message->secs = htobe16(secs);
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if (client->state == DHCP_STATE_RENEWING ||
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client->state == DHCP_STATE_REBINDING)
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message->ciaddr = client->lease->address;
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memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
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(*opt)[0] = 0x63;
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(*opt)[1] = 0x82;
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(*opt)[2] = 0x53;
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(*opt)[3] = 0x63;
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*opt += 4;
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err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1,
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&type);
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if (err < 0)
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return err;
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/* Some DHCP servers will refuse to issue an DHCP lease if the Cliient
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Identifier option is not set */
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err = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
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ETH_ALEN, &client->mac_addr);
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if (err < 0)
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return err;
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if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
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err = dhcp_option_append(opt, optlen,
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DHCP_OPTION_PARAMETER_REQUEST_LIST,
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client->req_opts_size,
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client->req_opts);
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if (err < 0)
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return err;
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/* Some DHCP servers will send bigger DHCP packets than the
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defined default size unless the Maximum Messge Size option
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is explicitely set */
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max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
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DHCP_CLIENT_MIN_OPTIONS_SIZE);
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err = dhcp_option_append(opt, optlen,
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DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
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2, &max_size);
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if (err < 0)
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return err;
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}
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return 0;
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}
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static uint16_t client_checksum(void *buf, int len)
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{
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uint32_t sum;
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uint16_t *check;
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int i;
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uint8_t *odd;
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sum = 0;
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check = buf;
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for (i = 0; i < len / 2 ; i++)
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sum += check[i];
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if (len & 0x01) {
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odd = buf;
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sum += odd[len - 1];
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}
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while (sum >> 16)
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sum = (sum & 0xffff) + (sum >> 16);
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return ~sum;
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}
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static void client_append_ip_headers(DHCPPacket *packet, uint16_t len)
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{
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packet->ip.version = IPVERSION;
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packet->ip.ihl = DHCP_IP_SIZE / 4;
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packet->ip.tot_len = htobe16(len);
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packet->ip.protocol = IPPROTO_UDP;
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packet->ip.saddr = INADDR_ANY;
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packet->ip.daddr = INADDR_BROADCAST;
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packet->udp.source = htobe16(DHCP_PORT_CLIENT);
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packet->udp.dest = htobe16(DHCP_PORT_SERVER);
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packet->udp.len = htobe16(len - DHCP_IP_SIZE);
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packet->ip.check = packet->udp.len;
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packet->udp.check = client_checksum(&packet->ip.ttl, len - 8);
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packet->ip.ttl = IPDEFTTL;
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packet->ip.check = 0;
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packet->ip.check = client_checksum(&packet->ip, DHCP_IP_SIZE);
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}
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static int client_send_discover(sd_dhcp_client *client, uint16_t secs)
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{
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int err = 0;
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_cleanup_free_ DHCPPacket *discover;
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size_t optlen, len;
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uint8_t *opt;
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optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
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len = sizeof(DHCPPacket) + optlen;
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discover = malloc0(len);
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if (!discover)
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return -ENOMEM;
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err = client_packet_init(client, DHCP_DISCOVER, &discover->dhcp,
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secs, &opt, &optlen);
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if (err < 0)
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return err;
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|
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if (client->last_addr != INADDR_ANY) {
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err = dhcp_option_append(&opt, &optlen,
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DHCP_OPTION_REQUESTED_IP_ADDRESS,
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4, &client->last_addr);
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if (err < 0)
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return err;
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}
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|
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err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
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if (err < 0)
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return err;
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client_append_ip_headers(discover, len);
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err = dhcp_network_send_raw_socket(client->fd, &client->link,
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discover, len);
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return err;
|
|
}
|
|
|
|
static int client_send_request(sd_dhcp_client *client, uint16_t secs)
|
|
{
|
|
_cleanup_free_ DHCPPacket *request;
|
|
size_t optlen, len;
|
|
int err;
|
|
uint8_t *opt;
|
|
|
|
optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
|
|
len = DHCP_MESSAGE_SIZE + optlen;
|
|
|
|
request = malloc0(len);
|
|
if (!request)
|
|
return -ENOMEM;
|
|
|
|
err = client_packet_init(client, DHCP_REQUEST, &request->dhcp, secs,
|
|
&opt, &optlen);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
if (client->state == DHCP_STATE_REQUESTING) {
|
|
err = dhcp_option_append(&opt, &optlen,
|
|
DHCP_OPTION_REQUESTED_IP_ADDRESS,
|
|
4, &client->lease->address);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
err = dhcp_option_append(&opt, &optlen,
|
|
DHCP_OPTION_SERVER_IDENTIFIER,
|
|
4, &client->lease->server_address);
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
|
|
err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
if (client->state == DHCP_STATE_RENEWING) {
|
|
err = dhcp_network_send_udp_socket(client->fd,
|
|
client->lease->server_address,
|
|
&request->dhcp,
|
|
len - DHCP_IP_UDP_SIZE);
|
|
} else {
|
|
client_append_ip_headers(request, len);
|
|
|
|
err = dhcp_network_send_raw_socket(client->fd, &client->link,
|
|
request, len);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static int client_timeout_resend(sd_event_source *s, uint64_t usec,
|
|
void *userdata)
|
|
{
|
|
sd_dhcp_client *client = userdata;
|
|
usec_t next_timeout = 0;
|
|
uint32_t time_left;
|
|
uint16_t secs;
|
|
int err = 0;
|
|
|
|
switch (client->state) {
|
|
case DHCP_STATE_RENEWING:
|
|
|
|
time_left = (client->lease->t2 - client->lease->t1)/2;
|
|
if (time_left < 60)
|
|
time_left = 60;
|
|
|
|
next_timeout = usec + time_left * USEC_PER_SEC;
|
|
|
|
break;
|
|
|
|
case DHCP_STATE_REBINDING:
|
|
|
|
time_left = (client->lease->lifetime - client->lease->t2)/2;
|
|
if (time_left < 60)
|
|
time_left = 60;
|
|
|
|
next_timeout = usec + time_left * USEC_PER_SEC;
|
|
break;
|
|
|
|
case DHCP_STATE_INIT:
|
|
case DHCP_STATE_INIT_REBOOT:
|
|
case DHCP_STATE_REBOOTING:
|
|
case DHCP_STATE_SELECTING:
|
|
case DHCP_STATE_REQUESTING:
|
|
case DHCP_STATE_BOUND:
|
|
|
|
if (client->attempt < 64)
|
|
client->attempt *= 2;
|
|
|
|
next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC;
|
|
|
|
break;
|
|
}
|
|
|
|
next_timeout += (random_u32() & 0x1fffff);
|
|
|
|
err = sd_event_add_monotonic(client->event, next_timeout,
|
|
10 * USEC_PER_MSEC,
|
|
client_timeout_resend, client,
|
|
&client->timeout_resend);
|
|
if (err < 0)
|
|
goto error;
|
|
|
|
secs = (usec - client->start_time) / USEC_PER_SEC;
|
|
|
|
switch (client->state) {
|
|
case DHCP_STATE_INIT:
|
|
err = client_send_discover(client, secs);
|
|
if (err >= 0) {
|
|
client->state = DHCP_STATE_SELECTING;
|
|
client->attempt = 1;
|
|
} else {
|
|
if (client->attempt >= 64)
|
|
goto error;
|
|
}
|
|
|
|
break;
|
|
|
|
case DHCP_STATE_SELECTING:
|
|
err = client_send_discover(client, secs);
|
|
if (err < 0 && client->attempt >= 64)
|
|
goto error;
|
|
|
|
break;
|
|
|
|
case DHCP_STATE_REQUESTING:
|
|
case DHCP_STATE_RENEWING:
|
|
case DHCP_STATE_REBINDING:
|
|
err = client_send_request(client, secs);
|
|
if (err < 0 && client->attempt >= 64)
|
|
goto error;
|
|
|
|
client->request_sent = usec;
|
|
|
|
break;
|
|
|
|
case DHCP_STATE_INIT_REBOOT:
|
|
case DHCP_STATE_REBOOTING:
|
|
case DHCP_STATE_BOUND:
|
|
|
|
break;
|
|
}
|
|
|
|
return 0;
|
|
|
|
error:
|
|
client_stop(client, err);
|
|
|
|
/* Errors were dealt with when stopping the client, don't spill
|
|
errors into the event loop handler */
|
|
return 0;
|
|
}
|
|
|
|
static int client_initialize_events(sd_dhcp_client *client, usec_t usec)
|
|
{
|
|
int r;
|
|
|
|
r = sd_event_add_io(client->event, client->fd, EPOLLIN,
|
|
client_receive_message, client,
|
|
&client->receive_message);
|
|
if (r < 0)
|
|
goto error;
|
|
|
|
r = sd_event_add_monotonic(client->event, usec, 0,
|
|
client_timeout_resend, client,
|
|
&client->timeout_resend);
|
|
|
|
error:
|
|
if (r < 0)
|
|
client_stop(client, r);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
static int client_timeout_expire(sd_event_source *s, uint64_t usec,
|
|
void *userdata)
|
|
{
|
|
sd_dhcp_client *client = userdata;
|
|
|
|
client_stop(client, DHCP_EVENT_EXPIRED);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata)
|
|
{
|
|
sd_dhcp_client *client = userdata;
|
|
int r;
|
|
|
|
if (client->fd >= 0) {
|
|
client->receive_message =
|
|
sd_event_source_unref(client->receive_message);
|
|
close(client->fd);
|
|
client->fd = -1;
|
|
}
|
|
|
|
client->state = DHCP_STATE_REBINDING;
|
|
client->attempt = 1;
|
|
|
|
r = dhcp_network_bind_raw_socket(client->index, &client->link);
|
|
if (r < 0) {
|
|
client_stop(client, r);
|
|
return 0;
|
|
}
|
|
|
|
client->fd = r;
|
|
|
|
return client_initialize_events(client, usec);
|
|
}
|
|
|
|
static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata)
|
|
{
|
|
sd_dhcp_client *client = userdata;
|
|
int r;
|
|
|
|
client->state = DHCP_STATE_RENEWING;
|
|
client->attempt = 1;
|
|
|
|
r = dhcp_network_bind_udp_socket(client->index,
|
|
client->lease->address);
|
|
if (r < 0) {
|
|
client_stop(client, r);
|
|
return 0;
|
|
}
|
|
|
|
client->fd = r;
|
|
|
|
return client_initialize_events(client, usec);
|
|
}
|
|
|
|
static int client_parse_offer(uint8_t code, uint8_t len, const uint8_t *option,
|
|
void *user_data)
|
|
{
|
|
DHCPLease *lease = user_data;
|
|
be32_t val;
|
|
|
|
switch(code) {
|
|
|
|
case DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
|
|
if (len == 4) {
|
|
memcpy(&val, option, 4);
|
|
lease->lifetime = be32toh(val);
|
|
}
|
|
|
|
break;
|
|
|
|
case DHCP_OPTION_SERVER_IDENTIFIER:
|
|
if (len >= 4)
|
|
memcpy(&lease->server_address, option, 4);
|
|
|
|
break;
|
|
|
|
case DHCP_OPTION_SUBNET_MASK:
|
|
if (len >= 4)
|
|
memcpy(&lease->subnet_mask, option, 4);
|
|
|
|
break;
|
|
|
|
case DHCP_OPTION_ROUTER:
|
|
if (len >= 4)
|
|
memcpy(&lease->router, option, 4);
|
|
|
|
break;
|
|
|
|
case DHCP_OPTION_DOMAIN_NAME_SERVER:
|
|
if (len >= 4) {
|
|
unsigned i;
|
|
|
|
in_addrs_free(lease->dns);
|
|
|
|
lease->dns = new0(struct in_addr*, len / 4 + 1);
|
|
if (!lease->dns)
|
|
return -ENOMEM;
|
|
|
|
for (i = 0; i < len / 4; i++) {
|
|
lease->dns[i] = new0(struct in_addr, 1);
|
|
memcpy(&lease->dns[i]->s_addr, option + 4 * i, 4);
|
|
}
|
|
|
|
lease->dns[len / 4] = NULL;
|
|
}
|
|
|
|
break;
|
|
|
|
case DHCP_OPTION_INTERFACE_MTU:
|
|
if (len >= 2) {
|
|
be16_t mtu;
|
|
|
|
memcpy(&mtu, option, 2);
|
|
lease->mtu = be16toh(mtu);
|
|
|
|
if (lease->mtu < 68)
|
|
lease->mtu = 0;
|
|
}
|
|
|
|
break;
|
|
|
|
case DHCP_OPTION_HOST_NAME:
|
|
if (len >= 1) {
|
|
free(lease->hostname);
|
|
lease->hostname = strndup((const char *)option, len);
|
|
}
|
|
|
|
break;
|
|
|
|
case DHCP_OPTION_RENEWAL_T1_TIME:
|
|
if (len == 4) {
|
|
memcpy(&val, option, 4);
|
|
lease->t1 = be32toh(val);
|
|
}
|
|
|
|
break;
|
|
|
|
case DHCP_OPTION_REBINDING_T2_TIME:
|
|
if (len == 4) {
|
|
memcpy(&val, option, 4);
|
|
lease->t2 = be32toh(val);
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int client_verify_headers(sd_dhcp_client *client, DHCPPacket *message,
|
|
size_t len)
|
|
{
|
|
size_t hdrlen;
|
|
|
|
if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE))
|
|
return -EINVAL;
|
|
|
|
hdrlen = message->ip.ihl * 4;
|
|
if (hdrlen < 20 || hdrlen > len || client_checksum(&message->ip,
|
|
hdrlen))
|
|
return -EINVAL;
|
|
|
|
message->ip.check = message->udp.len;
|
|
message->ip.ttl = 0;
|
|
|
|
if (hdrlen + be16toh(message->udp.len) > len ||
|
|
client_checksum(&message->ip.ttl, be16toh(message->udp.len) + 12))
|
|
return -EINVAL;
|
|
|
|
if (be16toh(message->udp.source) != DHCP_PORT_SERVER ||
|
|
be16toh(message->udp.dest) != DHCP_PORT_CLIENT)
|
|
return -EINVAL;
|
|
|
|
if (message->dhcp.op != BOOTREPLY)
|
|
return -EINVAL;
|
|
|
|
if (be32toh(message->dhcp.xid) != client->xid)
|
|
return -EINVAL;
|
|
|
|
if (memcmp(&message->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet,
|
|
ETHER_ADDR_LEN))
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
|
|
size_t len)
|
|
{
|
|
int err;
|
|
DHCPLease *lease;
|
|
|
|
err = client_verify_headers(client, offer, len);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
lease = new0(DHCPLease, 1);
|
|
if (!lease)
|
|
return -ENOMEM;
|
|
|
|
len = len - DHCP_IP_UDP_SIZE;
|
|
if (dhcp_option_parse(&offer->dhcp, len, client_parse_offer,
|
|
lease) != DHCP_OFFER)
|
|
goto error;
|
|
|
|
lease->address = offer->dhcp.yiaddr;
|
|
|
|
if (lease->address == INADDR_ANY ||
|
|
lease->server_address == INADDR_ANY ||
|
|
lease->subnet_mask == INADDR_ANY ||
|
|
lease->lifetime == 0)
|
|
goto error;
|
|
|
|
client->lease = lease;
|
|
|
|
return 0;
|
|
|
|
error:
|
|
free(lease);
|
|
|
|
return -ENOMSG;
|
|
}
|
|
|
|
static int client_receive_ack(sd_dhcp_client *client, const uint8_t *buf,
|
|
size_t len)
|
|
{
|
|
int r;
|
|
DHCPPacket *ack;
|
|
DHCPMessage *dhcp;
|
|
DHCPLease *lease;
|
|
|
|
if (client->state == DHCP_STATE_RENEWING) {
|
|
dhcp = (DHCPMessage *)buf;
|
|
} else {
|
|
ack = (DHCPPacket *)buf;
|
|
|
|
r = client_verify_headers(client, ack, len);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
dhcp = &ack->dhcp;
|
|
len -= DHCP_IP_UDP_SIZE;
|
|
}
|
|
|
|
lease = new0(DHCPLease, 1);
|
|
if (!lease)
|
|
return -ENOMEM;
|
|
|
|
r = dhcp_option_parse(dhcp, len, client_parse_offer, lease);
|
|
|
|
if (r == DHCP_NAK) {
|
|
r = DHCP_EVENT_NO_LEASE;
|
|
goto error;
|
|
}
|
|
|
|
if (r != DHCP_ACK) {
|
|
r = -ENOMSG;
|
|
goto error;
|
|
}
|
|
|
|
lease->address = dhcp->yiaddr;
|
|
|
|
if (lease->address == INADDR_ANY ||
|
|
lease->server_address == INADDR_ANY ||
|
|
lease->subnet_mask == INADDR_ANY || lease->lifetime == 0) {
|
|
r = -ENOMSG;
|
|
goto error;
|
|
}
|
|
|
|
r = DHCP_EVENT_IP_ACQUIRE;
|
|
if (client->lease) {
|
|
if (client->lease->address != lease->address ||
|
|
client->lease->subnet_mask != lease->subnet_mask ||
|
|
client->lease->router != lease->router) {
|
|
r = DHCP_EVENT_IP_CHANGE;
|
|
}
|
|
|
|
free(client->lease);
|
|
}
|
|
|
|
client->lease = lease;
|
|
|
|
return r;
|
|
|
|
error:
|
|
free(lease);
|
|
|
|
return r;
|
|
}
|
|
|
|
static uint64_t client_compute_timeout(uint64_t request_sent,
|
|
uint32_t lifetime)
|
|
{
|
|
return request_sent + (lifetime - 3) * USEC_PER_SEC +
|
|
+ (random_u32() & 0x1fffff);
|
|
}
|
|
|
|
static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec)
|
|
{
|
|
int err;
|
|
uint64_t next_timeout;
|
|
|
|
if (client->lease->lifetime < 10)
|
|
return -EINVAL;
|
|
|
|
client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
|
|
client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
|
|
client->timeout_expire = sd_event_source_unref(client->timeout_expire);
|
|
|
|
if (!client->lease->t1)
|
|
client->lease->t1 = client->lease->lifetime / 2;
|
|
|
|
next_timeout = client_compute_timeout(client->request_sent,
|
|
client->lease->t1);
|
|
if (next_timeout < usec)
|
|
return -EINVAL;
|
|
|
|
err = sd_event_add_monotonic(client->event, next_timeout,
|
|
10 * USEC_PER_MSEC,
|
|
client_timeout_t1, client,
|
|
&client->timeout_t1);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
if (!client->lease->t2)
|
|
client->lease->t2 = client->lease->lifetime * 7 / 8;
|
|
|
|
if (client->lease->t2 < client->lease->t1)
|
|
return -EINVAL;
|
|
|
|
if (client->lease->lifetime < client->lease->t2)
|
|
return -EINVAL;
|
|
|
|
next_timeout = client_compute_timeout(client->request_sent,
|
|
client->lease->t2);
|
|
if (next_timeout < usec)
|
|
return -EINVAL;
|
|
|
|
err = sd_event_add_monotonic(client->event, next_timeout,
|
|
10 * USEC_PER_MSEC,
|
|
client_timeout_t2, client,
|
|
&client->timeout_t2);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
next_timeout = client_compute_timeout(client->request_sent,
|
|
client->lease->lifetime);
|
|
if (next_timeout < usec)
|
|
return -EINVAL;
|
|
|
|
err = sd_event_add_monotonic(client->event, next_timeout,
|
|
10 * USEC_PER_MSEC,
|
|
client_timeout_expire, client,
|
|
&client->timeout_expire);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int client_receive_message(sd_event_source *s, int fd,
|
|
uint32_t revents, void *userdata)
|
|
{
|
|
sd_dhcp_client *client = userdata;
|
|
uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
|
|
int buflen = sizeof(buf);
|
|
int len, r = 0, notify_event = 0;
|
|
DHCPPacket *message;
|
|
usec_t time_now;
|
|
|
|
len = read(fd, &buf, buflen);
|
|
if (len < 0)
|
|
return 0;
|
|
|
|
r = sd_event_get_now_monotonic(client->event, &time_now);
|
|
if (r < 0)
|
|
goto error;
|
|
|
|
switch (client->state) {
|
|
case DHCP_STATE_SELECTING:
|
|
|
|
message = (DHCPPacket *)&buf;
|
|
|
|
if (client_receive_offer(client, message, len) >= 0) {
|
|
|
|
client->timeout_resend =
|
|
sd_event_source_unref(client->timeout_resend);
|
|
|
|
client->state = DHCP_STATE_REQUESTING;
|
|
client->attempt = 1;
|
|
|
|
r = sd_event_add_monotonic(client->event, time_now, 0,
|
|
client_timeout_resend,
|
|
client,
|
|
&client->timeout_resend);
|
|
if (r < 0)
|
|
goto error;
|
|
}
|
|
|
|
break;
|
|
|
|
case DHCP_STATE_REQUESTING:
|
|
case DHCP_STATE_RENEWING:
|
|
case DHCP_STATE_REBINDING:
|
|
|
|
r = client_receive_ack(client, buf, len);
|
|
|
|
if (r == DHCP_EVENT_NO_LEASE)
|
|
goto error;
|
|
|
|
if (r >= 0) {
|
|
client->timeout_resend =
|
|
sd_event_source_unref(client->timeout_resend);
|
|
|
|
if (client->state == DHCP_STATE_REQUESTING)
|
|
notify_event = DHCP_EVENT_IP_ACQUIRE;
|
|
else if (r != DHCP_EVENT_IP_ACQUIRE)
|
|
notify_event = r;
|
|
|
|
client->state = DHCP_STATE_BOUND;
|
|
client->attempt = 1;
|
|
|
|
client->last_addr = client->lease->address;
|
|
|
|
r = client_set_lease_timeouts(client, time_now);
|
|
if (r < 0)
|
|
goto error;
|
|
|
|
if (notify_event)
|
|
client_notify(client, notify_event);
|
|
|
|
client->receive_message =
|
|
sd_event_source_unref(client->receive_message);
|
|
close(client->fd);
|
|
client->fd = -1;
|
|
}
|
|
|
|
r = 0;
|
|
|
|
break;
|
|
|
|
case DHCP_STATE_INIT:
|
|
case DHCP_STATE_INIT_REBOOT:
|
|
case DHCP_STATE_REBOOTING:
|
|
case DHCP_STATE_BOUND:
|
|
|
|
break;
|
|
}
|
|
|
|
error:
|
|
if (r < 0 || r == DHCP_EVENT_NO_LEASE)
|
|
return client_stop(client, r);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int sd_dhcp_client_start(sd_dhcp_client *client)
|
|
{
|
|
int r;
|
|
|
|
assert_return(client, -EINVAL);
|
|
assert_return(client->index > 0, -EINVAL);
|
|
assert_return(client->state == DHCP_STATE_INIT ||
|
|
client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
|
|
|
|
client->xid = random_u32();
|
|
|
|
r = dhcp_network_bind_raw_socket(client->index, &client->link);
|
|
|
|
if (r < 0) {
|
|
client_stop(client, r);
|
|
return r;
|
|
}
|
|
|
|
client->fd = r;
|
|
client->start_time = now(CLOCK_MONOTONIC);
|
|
|
|
return client_initialize_events(client, client->start_time);
|
|
}
|
|
|
|
int sd_dhcp_client_stop(sd_dhcp_client *client)
|
|
{
|
|
return client_stop(client, DHCP_EVENT_STOP);
|
|
}
|
|
|
|
sd_dhcp_client *sd_dhcp_client_free(sd_dhcp_client *client)
|
|
{
|
|
assert_return(client, NULL);
|
|
|
|
sd_dhcp_client_stop(client);
|
|
|
|
sd_event_unref(client->event);
|
|
free(client->req_opts);
|
|
free(client);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
sd_dhcp_client *sd_dhcp_client_new(sd_event *event)
|
|
{
|
|
sd_dhcp_client *client;
|
|
|
|
assert_return(event, NULL);
|
|
|
|
client = new0(sd_dhcp_client, 1);
|
|
if (!client)
|
|
return NULL;
|
|
|
|
client->event = sd_event_ref(event);
|
|
client->state = DHCP_STATE_INIT;
|
|
client->index = -1;
|
|
client->fd = -1;
|
|
client->attempt = 1;
|
|
|
|
client->req_opts_size = ELEMENTSOF(default_req_opts);
|
|
|
|
client->req_opts = memdup(default_req_opts, client->req_opts_size);
|
|
if (!client->req_opts) {
|
|
free(client);
|
|
return NULL;
|
|
}
|
|
|
|
return client;
|
|
}
|