+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)
+{
+ return 0;
+}
+
+static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata)
+{
+ return 0;
+}
+
+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_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, DHCPPacket *offer,
+ size_t len)
+{
+ int r;
+ DHCPLease *lease;
+
+ 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_NAK) {
+ r = DHCP_EVENT_NO_LEASE;
+ goto error;
+ }
+
+ if (r != DHCP_ACK) {
+ r = -ENOMSG;
+ 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) {
+ 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_u() & 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;
+
+ 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_raw_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;
+ 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;
+
+ message = (DHCPPacket *)&buf;
+
+ switch (client->state) {
+ case DHCP_STATE_SELECTING:
+
+ 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:
+
+ r = client_receive_ack(client, message, len);
+ if (r == DHCP_EVENT_NO_LEASE)
+ goto error;
+
+ if (r >= 0) {
+ client->timeout_resend =
+ sd_event_source_unref(client->timeout_resend);
+
+ 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;
+
+ client_notify(client, DHCP_EVENT_IP_ACQUIRE);
+
+ 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:
+ case DHCP_STATE_RENEWING:
+ case DHCP_STATE_REBINDING:
+
+ break;
+ }
+
+error:
+ if (r < 0 || r == DHCP_EVENT_NO_LEASE)
+ return client_stop(client, r);
+
+ return 0;
+}
+