+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;
+ }
+
+ return 0;
+}
+
+static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
+ size_t len)
+{
+ size_t hdrlen;
+ DHCPLease *lease;
+
+ if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE))
+ return -EINVAL;
+
+ hdrlen = offer->ip.ihl * 4;
+ if (hdrlen < 20 || hdrlen > len || client_checksum(&offer->ip,
+ hdrlen))
+ return -EINVAL;
+
+ offer->ip.check = offer->udp.len;
+ offer->ip.ttl = 0;
+
+ if (hdrlen + be16toh(offer->udp.len) > len ||
+ client_checksum(&offer->ip.ttl, be16toh(offer->udp.len) + 12))
+ return -EINVAL;
+
+ if (be16toh(offer->udp.source) != DHCP_PORT_SERVER ||
+ be16toh(offer->udp.dest) != DHCP_PORT_CLIENT)
+ return -EINVAL;
+
+ if (offer->dhcp.op != BOOTREPLY)
+ return -EINVAL;
+
+ if (be32toh(offer->dhcp.xid) != client->xid)
+ return -EINVAL;
+
+ if (memcmp(&offer->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet,
+ ETHER_ADDR_LEN))
+ return -EINVAL;
+
+ 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_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, err = 0;
+ DHCPPacket *message;
+ usec_t time_now;
+
+ len = read(fd, &buf, buflen);
+ if (len < 0)
+ return 0;
+
+ err = sd_event_get_now_monotonic(client->event, &time_now);
+ if (err < 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;
+
+ err = sd_event_add_monotonic(client->event, time_now, 0,
+ client_timeout_resend,
+ client,
+ &client->timeout_resend);
+ if (err < 0)
+ goto error;
+ }
+
+ break;
+
+ case DHCP_STATE_INIT:
+ case DHCP_STATE_INIT_REBOOT:
+ case DHCP_STATE_REBOOTING:
+ case DHCP_STATE_REQUESTING:
+ case DHCP_STATE_BOUND:
+ case DHCP_STATE_RENEWING:
+ case DHCP_STATE_REBINDING:
+
+ break;
+ }
+
+error:
+ if (err < 0)
+ return client_stop(client, err);
+
+ return 0;
+}
+