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Diffstat (limited to 'src/libsystemd-dhcp/sd-dhcp-client.c')
-rw-r--r--src/libsystemd-dhcp/sd-dhcp-client.c1254
1 files changed, 1254 insertions, 0 deletions
diff --git a/src/libsystemd-dhcp/sd-dhcp-client.c b/src/libsystemd-dhcp/sd-dhcp-client.c
new file mode 100644
index 0000000000..3b7b9f4ccd
--- /dev/null
+++ b/src/libsystemd-dhcp/sd-dhcp-client.c
@@ -0,0 +1,1254 @@
+/***
+ This file is part of systemd.
+
+ Copyright (C) 2013 Intel Corporation. All rights reserved.
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <net/ethernet.h>
+#include <sys/param.h>
+
+#include "util.h"
+#include "list.h"
+
+#include "dhcp-protocol.h"
+#include "dhcp-internal.h"
+#include "sd-dhcp-client.h"
+
+#define DHCP_CLIENT_MIN_OPTIONS_SIZE 312
+
+#define client_state_machine_check(s, r) \
+ do { \
+ if (s != DHCP_STATE_BOUND && \
+ s != DHCP_STATE_RENEWING && \
+ s != DHCP_STATE_REBINDING) { \
+ return (r); \
+ } \
+ } while (false)
+
+struct DHCPLease {
+ uint32_t t1;
+ uint32_t t2;
+ uint32_t lifetime;
+ be32_t address;
+ be32_t server_address;
+ be32_t subnet_mask;
+ be32_t router;
+ struct in_addr *dns;
+ size_t dns_size;
+ uint16_t mtu;
+ char *domainname;
+ char *hostname;
+};
+
+typedef struct DHCPLease DHCPLease;
+
+struct sd_dhcp_client {
+ DHCPState state;
+ sd_event *event;
+ int event_priority;
+ sd_event_source *timeout_resend;
+ int index;
+ int fd;
+ union sockaddr_union link;
+ sd_event_source *receive_message;
+ uint8_t *req_opts;
+ size_t req_opts_allocated;
+ size_t req_opts_size;
+ be32_t last_addr;
+ struct ether_addr mac_addr;
+ uint32_t xid;
+ usec_t start_time;
+ unsigned int attempt;
+ usec_t request_sent;
+ sd_event_source *timeout_t1;
+ sd_event_source *timeout_t2;
+ sd_event_source *timeout_expire;
+ sd_dhcp_client_cb_t cb;
+ void *userdata;
+ DHCPLease *lease;
+};
+
+static const uint8_t default_req_opts[] = {
+ DHCP_OPTION_SUBNET_MASK,
+ DHCP_OPTION_ROUTER,
+ DHCP_OPTION_HOST_NAME,
+ DHCP_OPTION_DOMAIN_NAME,
+ DHCP_OPTION_DOMAIN_NAME_SERVER,
+ DHCP_OPTION_NTP_SERVER,
+};
+
+static int client_receive_message(sd_event_source *s, int fd,
+ uint32_t revents, void *userdata);
+
+int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb,
+ void *userdata) {
+ assert_return(client, -EINVAL);
+
+ client->cb = cb;
+ client->userdata = userdata;
+
+ return 0;
+}
+
+int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option) {
+ size_t i;
+
+ assert_return(client, -EINVAL);
+ assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
+
+ switch(option) {
+ case DHCP_OPTION_PAD:
+ case DHCP_OPTION_OVERLOAD:
+ case DHCP_OPTION_MESSAGE_TYPE:
+ case DHCP_OPTION_PARAMETER_REQUEST_LIST:
+ case DHCP_OPTION_END:
+ return -EINVAL;
+
+ default:
+ break;
+ }
+
+ for (i = 0; i < client->req_opts_size; i++)
+ if (client->req_opts[i] == option)
+ return -EEXIST;
+
+ if (!GREEDY_REALLOC(client->req_opts, client->req_opts_allocated,
+ client->req_opts_size + 1))
+ return -ENOMEM;
+
+ client->req_opts[client->req_opts_size++] = option;
+
+ return 0;
+}
+
+int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
+ const struct in_addr *last_addr) {
+ assert_return(client, -EINVAL);
+ assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
+
+ if (last_addr)
+ client->last_addr = last_addr->s_addr;
+ else
+ client->last_addr = INADDR_ANY;
+
+ return 0;
+}
+
+int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index) {
+ assert_return(client, -EINVAL);
+ assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
+ assert_return(interface_index >= -1, -EINVAL);
+
+ client->index = interface_index;
+
+ return 0;
+}
+
+int sd_dhcp_client_set_mac(sd_dhcp_client *client,
+ const struct ether_addr *addr) {
+ assert_return(client, -EINVAL);
+ assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
+
+ memcpy(&client->mac_addr, addr, ETH_ALEN);
+
+ return 0;
+}
+
+int sd_dhcp_client_get_address(sd_dhcp_client *client, struct in_addr *addr) {
+ assert_return(client, -EINVAL);
+ assert_return(addr, -EINVAL);
+
+ client_state_machine_check (client->state, -EADDRNOTAVAIL);
+
+ addr->s_addr = client->lease->address;
+
+ return 0;
+}
+
+int sd_dhcp_client_get_mtu(sd_dhcp_client *client, uint16_t *mtu) {
+ assert_return(client, -EINVAL);
+ assert_return(mtu, -EINVAL);
+
+ client_state_machine_check (client->state, -EADDRNOTAVAIL);
+
+ if (client->lease->mtu)
+ *mtu = client->lease->mtu;
+ else
+ return -ENOENT;
+
+ return 0;
+}
+
+int sd_dhcp_client_get_dns(sd_dhcp_client *client, struct in_addr **addr, size_t *addr_size) {
+ assert_return(client, -EINVAL);
+ assert_return(addr, -EINVAL);
+ assert_return(addr_size, -EINVAL);
+
+ client_state_machine_check (client->state, -EADDRNOTAVAIL);
+
+ if (client->lease->dns_size) {
+ *addr_size = client->lease->dns_size;
+ *addr = client->lease->dns;
+ } else
+ return -ENOENT;
+
+ return 0;
+}
+
+int sd_dhcp_client_get_domainname(sd_dhcp_client *client, const char **domainname) {
+ assert_return(client, -EINVAL);
+ assert_return(domainname, -EINVAL);
+
+ client_state_machine_check (client->state, -EADDRNOTAVAIL);
+
+ if (client->lease->domainname)
+ *domainname = client->lease->domainname;
+ else
+ return -ENOENT;
+
+ return 0;
+}
+
+int sd_dhcp_client_get_hostname(sd_dhcp_client *client, const char **hostname) {
+ assert_return(client, -EINVAL);
+ assert_return(hostname, -EINVAL);
+
+ client_state_machine_check (client->state, -EADDRNOTAVAIL);
+
+ if (client->lease->hostname)
+ *hostname = client->lease->hostname;
+ else
+ return -ENOENT;
+
+ return 0;
+}
+
+int sd_dhcp_client_prefixlen(const struct in_addr *addr) {
+ int len = 0;
+ uint32_t mask;
+
+ assert_return(addr, -EADDRNOTAVAIL);
+
+ mask = be32toh(addr->s_addr);
+ while (mask) {
+ len++;
+ mask = mask << 1;
+ }
+
+ return len;
+}
+
+int sd_dhcp_client_get_router(sd_dhcp_client *client, struct in_addr *addr) {
+ assert_return(client, -EINVAL);
+ assert_return(addr, -EINVAL);
+
+ client_state_machine_check (client->state, -EADDRNOTAVAIL);
+
+ addr->s_addr = client->lease->router;
+
+ return 0;
+}
+
+int sd_dhcp_client_get_netmask(sd_dhcp_client *client, struct in_addr *addr) {
+ assert_return(client, -EINVAL);
+ assert_return(addr, -EINVAL);
+
+ client_state_machine_check (client->state, -EADDRNOTAVAIL);
+
+ addr->s_addr = client->lease->subnet_mask;
+
+ return 0;
+}
+
+static int client_notify(sd_dhcp_client *client, int event) {
+ if (client->cb)
+ client->cb(client, event, client->userdata);
+
+ return 0;
+}
+
+static void lease_free(DHCPLease *lease) {
+ if (!lease)
+ return;
+
+ free(lease->hostname);
+ free(lease->domainname);
+ free(lease->dns);
+ free(lease);
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(DHCPLease*, lease_free);
+#define _cleanup_lease_free_ _cleanup_(lease_freep)
+
+static int client_stop(sd_dhcp_client *client, int error) {
+ assert_return(client, -EINVAL);
+
+ client->receive_message =
+ sd_event_source_unref(client->receive_message);
+
+ if (client->fd >= 0)
+ close(client->fd);
+ client->fd = -1;
+
+ client->timeout_resend = sd_event_source_unref(client->timeout_resend);
+
+ 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);
+
+ client->attempt = 1;
+
+ client_notify(client, error);
+
+ switch (client->state) {
+
+ case DHCP_STATE_INIT:
+ case DHCP_STATE_SELECTING:
+ case DHCP_STATE_REQUESTING:
+ case DHCP_STATE_BOUND:
+
+ client->start_time = 0;
+ client->state = DHCP_STATE_INIT;
+ break;
+
+ case DHCP_STATE_INIT_REBOOT:
+ case DHCP_STATE_REBOOTING:
+ case DHCP_STATE_RENEWING:
+ case DHCP_STATE_REBINDING:
+
+ break;
+ }
+
+ if (client->lease) {
+ lease_free(client->lease);
+ client->lease = NULL;
+ }
+
+ return 0;
+}
+
+static int client_packet_init(sd_dhcp_client *client, uint8_t type,
+ DHCPMessage *message, uint16_t secs,
+ uint8_t **opt, size_t *optlen) {
+ int err;
+ be16_t max_size;
+
+ *opt = (uint8_t *)(message + 1);
+
+ if (*optlen < 4)
+ return -ENOBUFS;
+ *optlen -= 4;
+
+ message->op = BOOTREQUEST;
+ message->htype = 1;
+ message->hlen = ETHER_ADDR_LEN;
+ message->xid = htobe32(client->xid);
+
+ /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
+ refuse to issue an DHCP lease if 'secs' is set to zero */
+ message->secs = htobe16(secs);
+
+ if (client->state == DHCP_STATE_RENEWING ||
+ client->state == DHCP_STATE_REBINDING)
+ message->ciaddr = client->lease->address;
+
+ memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
+ (*opt)[0] = 0x63;
+ (*opt)[1] = 0x82;
+ (*opt)[2] = 0x53;
+ (*opt)[3] = 0x63;
+
+ *opt += 4;
+
+ err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1,
+ &type);
+ if (err < 0)
+ return err;
+
+ /* Some DHCP servers will refuse to issue an DHCP lease if the Cliient
+ Identifier option is not set */
+ err = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
+ ETH_ALEN, &client->mac_addr);
+ if (err < 0)
+ return err;
+
+ if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
+ err = dhcp_option_append(opt, optlen,
+ DHCP_OPTION_PARAMETER_REQUEST_LIST,
+ client->req_opts_size,
+ client->req_opts);
+ if (err < 0)
+ return err;
+
+ /* Some DHCP servers will send bigger DHCP packets than the
+ defined default size unless the Maximum Messge Size option
+ is explicitely set */
+ max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
+ DHCP_CLIENT_MIN_OPTIONS_SIZE);
+ err = dhcp_option_append(opt, optlen,
+ DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
+ 2, &max_size);
+ if (err < 0)
+ return err;
+ }
+
+ return 0;
+}
+
+static uint16_t client_checksum(void *buf, int len) {
+ uint32_t sum;
+ uint16_t *check;
+ int i;
+ uint8_t *odd;
+
+ sum = 0;
+ check = buf;
+
+ for (i = 0; i < len / 2 ; i++)
+ sum += check[i];
+
+ if (len & 0x01) {
+ odd = buf;
+ sum += odd[len - 1];
+ }
+
+ while (sum >> 16)
+ sum = (sum & 0xffff) + (sum >> 16);
+
+ return ~sum;
+}
+
+static void client_append_ip_headers(DHCPPacket *packet, uint16_t len) {
+ packet->ip.version = IPVERSION;
+ packet->ip.ihl = DHCP_IP_SIZE / 4;
+ packet->ip.tot_len = htobe16(len);
+
+ packet->ip.protocol = IPPROTO_UDP;
+ packet->ip.saddr = INADDR_ANY;
+ packet->ip.daddr = INADDR_BROADCAST;
+
+ packet->udp.source = htobe16(DHCP_PORT_CLIENT);
+ packet->udp.dest = htobe16(DHCP_PORT_SERVER);
+ packet->udp.len = htobe16(len - DHCP_IP_SIZE);
+
+ packet->ip.check = packet->udp.len;
+ packet->udp.check = client_checksum(&packet->ip.ttl, len - 8);
+
+ packet->ip.ttl = IPDEFTTL;
+ packet->ip.check = 0;
+ packet->ip.check = client_checksum(&packet->ip, DHCP_IP_SIZE);
+}
+
+static int client_send_discover(sd_dhcp_client *client, uint16_t secs) {
+ int err = 0;
+ _cleanup_free_ DHCPPacket *discover;
+ size_t optlen, len;
+ uint8_t *opt;
+
+ optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
+ len = sizeof(DHCPPacket) + optlen;
+
+ discover = malloc0(len);
+
+ if (!discover)
+ return -ENOMEM;
+
+ err = client_packet_init(client, DHCP_DISCOVER, &discover->dhcp,
+ secs, &opt, &optlen);
+ if (err < 0)
+ return err;
+
+ if (client->last_addr != INADDR_ANY) {
+ err = dhcp_option_append(&opt, &optlen,
+ DHCP_OPTION_REQUESTED_IP_ADDRESS,
+ 4, &client->last_addr);
+ if (err < 0)
+ return err;
+ }
+
+ err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
+ if (err < 0)
+ return err;
+
+ client_append_ip_headers(discover, len);
+
+ err = dhcp_network_send_raw_socket(client->fd, &client->link,
+ discover, len);
+
+ 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 r = 0;
+
+ assert(s);
+ assert(client);
+ assert(client->event);
+
+ 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);
+
+ r = sd_event_add_monotonic(client->event, next_timeout,
+ 10 * USEC_PER_MSEC,
+ client_timeout_resend, client,
+ &client->timeout_resend);
+ if (r < 0)
+ goto error;
+
+ r = sd_event_source_set_priority(client->timeout_resend, client->event_priority);
+ if (r < 0)
+ goto error;
+
+ secs = (usec - client->start_time) / USEC_PER_SEC;
+
+ switch (client->state) {
+ case DHCP_STATE_INIT:
+ r = client_send_discover(client, secs);
+ if (r >= 0) {
+ client->state = DHCP_STATE_SELECTING;
+ client->attempt = 1;
+ } else {
+ if (client->attempt >= 64)
+ goto error;
+ }
+
+ break;
+
+ case DHCP_STATE_SELECTING:
+ r = client_send_discover(client, secs);
+ if (r < 0 && client->attempt >= 64)
+ goto error;
+
+ break;
+
+ case DHCP_STATE_REQUESTING:
+ case DHCP_STATE_RENEWING:
+ case DHCP_STATE_REBINDING:
+ r = client_send_request(client, secs);
+ if (r < 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, r);
+
+ /* 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;
+
+ assert(client);
+ assert(client->event);
+
+ 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_source_set_priority(client->receive_message, client->event_priority);
+ if (r < 0)
+ goto error;
+
+ r = sd_event_add_monotonic(client->event, usec, 0,
+ client_timeout_resend, client,
+ &client->timeout_resend);
+ if (r < 0)
+ goto error;
+
+ r = sd_event_source_set_priority(client->timeout_resend, client->event_priority);
+
+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;
+
+ lease->dns_size = len / 4;
+
+ free(lease->dns);
+ lease->dns = new0(struct in_addr, lease->dns_size);
+ if (!lease->dns)
+ return -ENOMEM;
+
+ for (i = 0; i < lease->dns_size; i++) {
+ memcpy(&lease->dns[i].s_addr, option + 4 * i, 4);
+ }
+ }
+
+ 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_DOMAIN_NAME:
+ if (len >= 1) {
+ free(lease->domainname);
+ lease->domainname = strndup((const char *)option, len);
+ }
+
+ 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) {
+ _cleanup_lease_free_ DHCPLease *lease = NULL;
+ int r;
+
+ r = client_verify_headers(client, offer, len);
+ if (r < 0)
+ return r;
+
+ lease = new0(DHCPLease, 1);
+ if (!lease)
+ return -ENOMEM;
+
+ len = len - DHCP_IP_UDP_SIZE;
+ r = dhcp_option_parse(&offer->dhcp, len, client_parse_offer,
+ lease);
+ if (r != DHCP_OFFER)
+ return -ENOMSG;
+
+ lease->address = offer->dhcp.yiaddr;
+
+ if (lease->address == INADDR_ANY ||
+ lease->server_address == INADDR_ANY ||
+ lease->subnet_mask == INADDR_ANY ||
+ lease->lifetime == 0)
+ return -ENOMSG;
+
+ client->lease = lease;
+ lease = NULL;
+
+ return 0;
+}
+
+static int client_receive_ack(sd_dhcp_client *client, const uint8_t *buf,
+ size_t len) {
+ DHCPPacket *ack;
+ DHCPMessage *dhcp;
+ _cleanup_lease_free_ DHCPLease *lease = NULL;
+ int r;
+
+ 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)
+ return DHCP_EVENT_NO_LEASE;
+
+ if (r != DHCP_ACK)
+ return -ENOMSG;
+
+ lease->address = dhcp->yiaddr;
+
+ if (lease->address == INADDR_ANY ||
+ lease->server_address == INADDR_ANY ||
+ lease->subnet_mask == INADDR_ANY || lease->lifetime == 0)
+ return -ENOMSG;
+
+ 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;
+ }
+
+ lease_free(client->lease);
+ }
+
+ client->lease = lease;
+ lease = NULL;
+
+ 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) {
+ uint64_t next_timeout;
+ int r;
+
+ assert(client);
+ assert(client->event);
+
+ 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;
+
+ r = sd_event_add_monotonic(client->event, next_timeout,
+ 10 * USEC_PER_MSEC,
+ client_timeout_t1, client,
+ &client->timeout_t1);
+ if (r < 0)
+ return r;
+
+ r = sd_event_source_set_priority(client->timeout_t1, client->event_priority);
+ if (r < 0)
+ return r;
+
+ 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;
+
+ r = sd_event_add_monotonic(client->event, next_timeout,
+ 10 * USEC_PER_MSEC,
+ client_timeout_t2, client,
+ &client->timeout_t2);
+ if (r < 0)
+ return r;
+
+ r = sd_event_source_set_priority(client->timeout_t2, client->event_priority);
+ if (r < 0)
+ return r;
+
+ next_timeout = client_compute_timeout(client->request_sent,
+ client->lease->lifetime);
+ if (next_timeout < usec)
+ return -EINVAL;
+
+ r = sd_event_add_monotonic(client->event, next_timeout,
+ 10 * USEC_PER_MSEC,
+ client_timeout_expire, client,
+ &client->timeout_expire);
+ if (r < 0)
+ return r;
+
+ r = sd_event_source_set_priority(client->timeout_expire, client->event_priority);
+ if (r < 0)
+ return r;
+
+ 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;
+
+ assert(s);
+ assert(client);
+ assert(client->event);
+
+ 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;
+
+ r = sd_event_source_set_priority(client->timeout_resend, client->event_priority);
+ 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->event, -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);
+}
+
+int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event, int priority) {
+ int r;
+
+ assert_return(client, -EINVAL);
+ assert_return(!client->event, -EBUSY);
+
+ if (event)
+ client->event = sd_event_ref(event);
+ else {
+ r = sd_event_default(&client->event);
+ if (r < 0)
+ return 0;
+ }
+
+ client->event_priority = priority;
+
+ return 0;
+}
+
+int sd_dhcp_client_detach_event(sd_dhcp_client *client) {
+ assert_return(client, -EINVAL);
+
+ client->event = sd_event_unref(client->event);
+
+ return 0;
+}
+
+sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) {
+ if (!client)
+ return NULL;
+
+ return client->event;
+}
+
+void sd_dhcp_client_free(sd_dhcp_client *client) {
+ if (!client)
+ return;
+
+ sd_dhcp_client_stop(client);
+ sd_dhcp_client_detach_event(client);
+
+ free(client->req_opts);
+ free(client);
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_free);
+#define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_freep)
+
+int sd_dhcp_client_new(sd_dhcp_client **ret) {
+ _cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL;
+
+ assert_return(ret, -EINVAL);
+
+ client = new0(sd_dhcp_client, 1);
+ if (!client)
+ return -ENOMEM;
+
+ 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)
+ return -ENOMEM;
+
+ *ret = client;
+ client = NULL;
+
+ return 0;
+}