Commit 4343e687 authored by Dean Camera's avatar Dean Camera
Browse files

Correct errors in the DHCP Server application in the Webserver project, that...

Correct errors in the DHCP Server application in the Webserver project, that was causing random server restarts and/or incorrectly allocated IP addresses.
parent 3cba88e4
......@@ -68,62 +68,83 @@ void DHCPServerApp_Callback(void)
DHCP_Header_t* const AppData = (DHCP_Header_t*)uip_appdata;
uint16_t AppDataSize = 0;
uint8_t DHCPMessageType;
if (!(DHCPCommon_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &DHCPMessageType)))
return;
uip_ipaddr_t Netmask, GatewayIPAddress;
struct uip_eth_addr RemoteMACAddress;
uint32_t TransactionID;
/* 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;
memcpy(&RemoteMACAddress, &AppData->ClientHardwareAddress, sizeof(struct uip_eth_addr));
uip_getnetmask(&Netmask);
uip_getdraddr(&GatewayIPAddress);
TransactionID = AppData->TransactionID;
uip_ipaddr_t Netmask, GatewayIPAddress, PreferredClientIP;
struct uip_eth_addr RemoteMACAddress;
uint32_t TransactionID;
switch (DHCPMessageType)
{
case DHCP_DISCOVER:
AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_OFFER, &RemoteMACAddress, 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;
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);
/* 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);
break;
case DHCP_REQUEST:
if (!(DHCPServerApp_CheckIfIPLeased(&AppData->YourIP)))
{
AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_ACK, &RemoteMACAddress, TransactionID);
/* 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);
DHCPServerApp_LeaseIP(&AppData->YourIP);
}
else
{
AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_NAK, &RemoteMACAddress, TransactionID);
}
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);
/* 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;
break;
case DHCP_RELEASE:
/* Mark the IP address as released in the allocation table */
DHCPServerApp_UnleaseIP(&uip_udp_conn->ripaddr);
break;
}
}
}
......@@ -139,8 +160,9 @@ void DHCPServerApp_Callback(void)
*/
static uint16_t DHCPServerApp_FillDHCPHeader(DHCP_Header_t* const DHCPHeader,
const uint8_t DHCPMessageType,
struct uip_eth_addr* ClientHardwareAddress,
uint32_t TransactionID)
const struct uip_eth_addr* const ClientHardwareAddress,
const uip_ipaddr_t* const PreferredClientIP,
const uint32_t TransactionID)
{
/* Erase existing packet data so that we start will all 0x00 DHCP header data */
memset(DHCPHeader, 0, sizeof(DHCP_Header_t));
......@@ -153,8 +175,7 @@ static uint16_t DHCPServerApp_FillDHCPHeader(DHCP_Header_t* const DHCPHeader,
DHCPHeader->ElapsedSeconds = 0;
DHCPHeader->Flags = 0;
memcpy(&DHCPHeader->NextServerIP, &uip_hostaddr, sizeof(uip_ipaddr_t));
if (uip_ipaddr_cmp(&DHCPHeader->YourIP, &uip_all_zeroes_addr))
DHCPServerApp_GetUnleasedIP(&DHCPHeader->YourIP);
memcpy(&DHCPHeader->YourIP, PreferredClientIP, sizeof(uip_ipaddr_t));
memcpy(&DHCPHeader->ClientHardwareAddress, ClientHardwareAddress, sizeof(struct uip_eth_addr));
DHCPHeader->Cookie = DHCP_MAGIC_COOKIE;
......@@ -176,12 +197,13 @@ static uint16_t DHCPServerApp_FillDHCPHeader(DHCP_Header_t* const DHCPHeader,
*
* \return Boolean true if the IP has already been leased to a client, false otherwise.
*/
static bool DHCPServerApp_CheckIfIPLeased(uip_ipaddr_t* IPAddress)
static bool DHCPServerApp_CheckIfIPLeased(const uip_ipaddr_t* const IPAddress)
{
uint8_t Byte = (IPAddress->u8[3] / 8);
uint8_t Mask = (1 << (IPAddress->u8[3] % 8));
if (!(IPAddress->u8[3] == uip_hostaddr.u8[3]) && !(LeasedIPs[Byte] & Mask))
/* Make sure that the requested IP address isn't already leased to the virtual server or another client */
if (IPAddress->u8[3] && !(IPAddress->u8[3] == uip_hostaddr.u8[3]) && !(LeasedIPs[Byte] & Mask))
return false;
else
return true;
......@@ -191,14 +213,17 @@ static bool DHCPServerApp_CheckIfIPLeased(uip_ipaddr_t* IPAddress)
*
* \param[out] NewIPAddress Location where the generated IP Address should be stored
*/
static void DHCPServerApp_GetUnleasedIP(uip_ipaddr_t* NewIPAddress)
static void DHCPServerApp_GetUnleasedIP(uip_ipaddr_t* const NewIPAddress)
{
uip_ipaddr_copy(NewIPAddress, &uip_hostaddr);
/** Look through the current subnet, skipping the broadcast and zero IP addresses */
for (uint8_t IP = 1; IP < 254; IP++)
{
/* Update new IP address to lease with the current IP address to test */
NewIPAddress->u8[3] = IP;
/* If we've found an unleased IP, abort with the updated IP stored for the called */
if (!(DHCPServerApp_CheckIfIPLeased(NewIPAddress)))
return;
}
......@@ -211,11 +236,12 @@ static void DHCPServerApp_GetUnleasedIP(uip_ipaddr_t* NewIPAddress)
*
* \pre The IP address must be within the same /24 subnet as the virtual webserver.
*/
static void DHCPServerApp_LeaseIP(uip_ipaddr_t* IPAddress)
static void DHCPServerApp_LeaseIP(const uip_ipaddr_t* const IPAddress)
{
uint8_t Byte = (IPAddress->u8[3] / 8);
uint8_t Mask = (1 << (IPAddress->u8[3] % 8));
/* Mark the IP address as leased in the allocation table */
LeasedIPs[Byte] |= Mask;
}
......@@ -226,11 +252,12 @@ static void DHCPServerApp_LeaseIP(uip_ipaddr_t* IPAddress)
*
* \pre The IP address must be within the same /24 subnet as the virtual webserver.
*/
static void DHCPServerApp_UnleaseIP(uip_ipaddr_t* IPAddress)
static void DHCPServerApp_UnleaseIP(const uip_ipaddr_t* const IPAddress)
{
uint8_t Byte = (IPAddress->u8[3] / 8);
uint8_t Mask = (1 << (IPAddress->u8[3] % 8));
/* Mark the IP address as unleased in the allocation table */
LeasedIPs[Byte] &= ~Mask;
}
#endif
......
......@@ -51,12 +51,13 @@
#if defined(INCLUDE_FROM_DHCPSERVERAPP_C)
static uint16_t DHCPServerApp_FillDHCPHeader(DHCP_Header_t* const DHCPHeader,
const uint8_t DHCPMessageType,
struct uip_eth_addr* ClientHardwareAddress,
uint32_t TransactionID);
static bool DHCPServerApp_CheckIfIPLeased(uip_ipaddr_t* IPAddress);
static void DHCPServerApp_GetUnleasedIP(uip_ipaddr_t* NewIPAddress);
static void DHCPServerApp_LeaseIP(uip_ipaddr_t* IPAddress);
static void DHCPServerApp_UnleaseIP(uip_ipaddr_t* IPAddress);
const struct uip_eth_addr* const ClientHardwareAddress,
const uip_ipaddr_t* const PreferredClientIP,
const uint32_t TransactionID);
static bool DHCPServerApp_CheckIfIPLeased(const uip_ipaddr_t* const IPAddress);
static void DHCPServerApp_GetUnleasedIP(uip_ipaddr_t* const NewIPAddress);
static void DHCPServerApp_LeaseIP(const uip_ipaddr_t* const IPAddress);
static void DHCPServerApp_UnleaseIP(const uip_ipaddr_t* const IPAddress);
#endif
#endif
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