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Correct errors in the DHCP Server application in the Webserver project, that was causing random server restarts and/or incorrectly allocated IP addresses.

This commit is contained in:
Dean Camera 2011-05-23 07:13:45 +00:00
parent 3cba88e4c0
commit 4343e68779
2 changed files with 90 additions and 62 deletions
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139
Projects/Webserver/Lib/DHCPServerApp.c
View File

@ -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;
memcpy(&RemoteMACAddress, &AppData->ClientHardwareAddress, sizeof(struct uip_eth_addr));
uip_getnetmask(&Netmask);
uip_getdraddr(&GatewayIPAddress);
TransactionID = AppData->TransactionID;
switch (DHCPMessageType)
/* Only process when new data arrives - don't retransmit lost packets */
if (uip_newdata())
{
case DHCP_DISCOVER:
AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_OFFER, &RemoteMACAddress, TransactionID);
/* Get the DHCP message type (if present), otherwise early-abort */
uint8_t DHCPMessageType;
if (!(DHCPCommon_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &DHCPMessageType)))
return;
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);
uip_ipaddr_t Netmask, GatewayIPAddress, PreferredClientIP;
struct uip_eth_addr RemoteMACAddress;
uint32_t TransactionID;
break;
case DHCP_REQUEST:
if (!(DHCPServerApp_CheckIfIPLeased(&AppData->YourIP)))
{
AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_ACK, &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;
/* 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);
sizeof(uip_ipaddr_t), &GatewayIPAddress);
DHCPServerApp_LeaseIP(&AppData->YourIP);
}
else
{
AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_NAK, &RemoteMACAddress, TransactionID);
}
/* 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

13
Projects/Webserver/Lib/DHCPServerApp.h
View File

@ -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