/** uIP stack application callback for the DHCP server. This function must be called each time the TCP/IP stack
* needs a UDP packet to be processed.
*/
void DHCPServerApp_Callback(void)
{
DHCP_Header_t* const AppData = (DHCP_Header_t*)uip_appdata;
uint16_t AppDataSize = 0;
/* Only process when new data arrives - don't retransmit lost packets */
if (uip_newdata())
{
/* Get the DHCP message type (if present), otherwise early-abort */
uint8_t DHCPMessageType;
if (!(DHCPCommon_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &DHCPMessageType)))
return;
uip_ipaddr_t Netmask, GatewayIPAddress, PreferredClientIP;
struct uip_eth_addr RemoteMACAddress;
uint32_t TransactionID;
/* Get configured network mask, gateway IP and extract out DHCP transaction ID and remote IP */
uip_getnetmask(&Netmask);
uip_getdraddr(&GatewayIPAddress);
memcpy(&RemoteMACAddress, &AppData->ClientHardwareAddress, sizeof(struct uip_eth_addr));
TransactionID = AppData->TransactionID;
/* Try to extract out the client's preferred IP address if it is indicated in the packet */
if (!(DHCPCommon_GetOption(AppData->Options, DHCP_OPTION_REQ_IPADDR, &PreferredClientIP)))
memcpy(&PreferredClientIP, &uip_all_zeroes_addr, sizeof(uip_ipaddr_t));
switch (DHCPMessageType)
{
case DHCP_DISCOVER:
/* If no preference was made or the preferred IP is already taken, find a new address */
if (DHCPServerApp_CheckIfIPLeased(&PreferredClientIP))
DHCPServerApp_GetUnleasedIP(&PreferredClientIP);
/* Create a new DHCP OFFER packet with the offered IP address */
AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_OFFER, &RemoteMACAddress, &PreferredClientIP, TransactionID);
/* Add network mask and router information to the list of DHCP OFFER packet options */
AppDataSize += DHCPCommon_SetOption(AppData->Options, DHCP_OPTION_SUBNET_MASK,
sizeof(uip_ipaddr_t), &Netmask);
AppDataSize += DHCPCommon_SetOption(AppData->Options, DHCP_OPTION_ROUTER,
sizeof(uip_ipaddr_t), &GatewayIPAddress);
/* Send the DHCP OFFER packet */
uip_poll_conn(BroadcastConnection);
memcpy(&uip_udp_conn->ripaddr, &uip_broadcast_addr, sizeof(uip_ipaddr_t));
uip_udp_send(AppDataSize);
break;
case DHCP_REQUEST:
/* Check to see if the requested IP address has already been leased to a client */
if (!(DHCPServerApp_CheckIfIPLeased(&PreferredClientIP)))
{
/* Create a new DHCP ACK packet to accept the IP address lease */
AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_ACK, &RemoteMACAddress, &PreferredClientIP, TransactionID);
/* Add network mask and router information to the list of DHCP ACK packet options */
AppDataSize += DHCPCommon_SetOption(AppData->Options, DHCP_OPTION_SUBNET_MASK,
sizeof(uip_ipaddr_t), &Netmask);
AppDataSize += DHCPCommon_SetOption(AppData->Options, DHCP_OPTION_ROUTER,
sizeof(uip_ipaddr_t), &GatewayIPAddress);
/* Mark the requested IP as leased to a client */
DHCPServerApp_LeaseIP(&PreferredClientIP);
}
else
{
/* Create a new DHCP NAK packet to reject the requested allocation */
AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_NAK, &RemoteMACAddress, &uip_all_zeroes_addr, TransactionID);
}
/* Send the DHCP ACK or NAK packet */
uip_poll_conn(BroadcastConnection);
memcpy(&uip_udp_conn->ripaddr, &uip_broadcast_addr, sizeof(uip_ipaddr_t));
uip_udp_send(AppDataSize);
break;
case DHCP_RELEASE:
/* Mark the IP address as released in the allocation table */
DHCPServerApp_UnleaseIP(&uip_udp_conn->ripaddr);
break;
}
}
}
/** uIP stack application callback for the DHCP client. This function must be called each time the TCP/IP stack
* needs a UDP packet to be processed.
*/
void DHCPClientApp_Callback(void)
{
uip_udp_appstate_t* const AppState = &uip_udp_conn->appstate;
DHCP_Header_t* const AppData = (DHCP_Header_t*)uip_appdata;
uint16_t AppDataSize = 0;
switch (AppState->DHCPClient.CurrentState)
{
case DHCP_STATE_SendDiscover:
/* Clear all DHCP settings, reset client IP address */
memset(&AppState->DHCPClient.DHCPOffer_Data, 0x00, sizeof(AppState->DHCPClient.DHCPOffer_Data));
uip_sethostaddr((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP);
/* Fill out the DHCP response header */
AppDataSize += DHCPClientApp_FillDHCPHeader(AppData, DHCP_DISCOVER, AppState);
/* Add the required DHCP options list to the packet */
uint8_t RequiredOptionList[] = {DHCP_OPTION_SUBNET_MASK, DHCP_OPTION_ROUTER, DHCP_OPTION_DNS_SERVER};
AppDataSize += DHCPCommon_SetOption(AppData->Options, DHCP_OPTION_REQ_LIST, sizeof(RequiredOptionList),
RequiredOptionList);
/* Send the DHCP DISCOVER packet */
uip_udp_send(AppDataSize);
/* Reset the timeout timer, progress to next state */
timer_reset(&AppState->DHCPClient.Timeout);
AppState->DHCPClient.CurrentState = DHCP_STATE_WaitForOffer;
break;
case DHCP_STATE_WaitForOffer:
if (!(uip_newdata()))
{
/* Check if the DHCP timeout period has expired while waiting for a response */
if (timer_expired(&AppState->DHCPClient.Timeout))
AppState->DHCPClient.CurrentState = DHCP_STATE_SendDiscover;
break;
}
uint8_t OfferResponse_MessageType;
if ((AppData->TransactionID == DHCP_TRANSACTION_ID) &&
DHCPCommon_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &OfferResponse_MessageType) &&
(OfferResponse_MessageType == DHCP_OFFER))
{
/* Received a DHCP offer for an IP address, copy over values for later request */
memcpy(&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP, &AppData->YourIP, sizeof(uip_ipaddr_t));
DHCPCommon_GetOption(AppData->Options, DHCP_OPTION_SUBNET_MASK, &AppState->DHCPClient.DHCPOffer_Data.Netmask);
DHCPCommon_GetOption(AppData->Options, DHCP_OPTION_ROUTER, &AppState->DHCPClient.DHCPOffer_Data.GatewayIP);
DHCPCommon_GetOption(AppData->Options, DHCP_OPTION_SERVER_ID, &AppState->DHCPClient.DHCPOffer_Data.ServerIP);
timer_reset(&AppState->DHCPClient.Timeout);
AppState->DHCPClient.CurrentState = DHCP_STATE_SendRequest;
}
break;
case DHCP_STATE_SendRequest:
/* Fill out the DHCP response header */
AppDataSize += DHCPClientApp_FillDHCPHeader(AppData, DHCP_REQUEST, AppState);
/* Add the DHCP REQUESTED IP ADDRESS option to the packet */
AppDataSize += DHCPCommon_SetOption(AppData->Options, DHCP_OPTION_REQ_IPADDR, sizeof(uip_ipaddr_t),
&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP);
/* Add the DHCP SERVER IP ADDRESS option to the packet */
AppDataSize += DHCPCommon_SetOption(AppData->Options, DHCP_OPTION_SERVER_ID, sizeof(uip_ipaddr_t),
&AppState->DHCPClient.DHCPOffer_Data.ServerIP);
/* Send the DHCP REQUEST packet */
uip_udp_send(AppDataSize);
/* Reset the timeout timer, progress to next state */
timer_reset(&AppState->DHCPClient.Timeout);
AppState->DHCPClient.CurrentState = DHCP_STATE_WaitForACK;
break;
case DHCP_STATE_WaitForACK:
if (!(uip_newdata()))
{
/* Check if the DHCP timeout period has expired while waiting for a response */
if (timer_expired(&AppState->DHCPClient.Timeout))
AppState->DHCPClient.CurrentState = DHCP_STATE_SendDiscover;
break;
}
uint8_t RequestResponse_MessageType;
if ((AppData->TransactionID == DHCP_TRANSACTION_ID) &&
DHCPCommon_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &RequestResponse_MessageType) &&
(RequestResponse_MessageType == DHCP_ACK))
{
/* Set the new network parameters from the DHCP server */
uip_sethostaddr((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP);
uip_setnetmask((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.Netmask);
uip_setdraddr((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.GatewayIP);
AppState->DHCPClient.CurrentState = DHCP_STATE_AddressLeased;
}
break;
}
}
