Dhcpv6StatusCode dhcpv6GetStatusCode(const uint8_t *options, size_t length)
{
uint16_t statusCode;
Dhcpv6Option *option;
Dhcpv6StatusCodeOption *statusCodeOption;
//Search for the Status Code option
option = dhcpv6GetOption(options, length, DHCPV6_OPTION_STATUS_CODE);
//Check whether the option has been found
if(option != NULL && ntohs(option->length) >= sizeof(Dhcpv6StatusCodeOption))
{
//The option contains a status code and a status message
statusCodeOption = (Dhcpv6StatusCodeOption *) option->value;
//Convert the status code from network byte order
statusCode = ntohs(statusCodeOption->statusCode);
}
else
{
//If the Status Code option does not appear in a message in which the option
//could appear, the status of the message is assumed to be Success
statusCode = DHCPV6_STATUS_SUCCESS;
}
//Return status code
return (Dhcpv6StatusCode) statusCode;
}
error_t dhcpv6ParseStatusCodeOption(const uint8_t *options, size_t length)
{
error_t error;
uint16_t statusCode;
Dhcpv6Option *option;
Dhcpv6StatusCodeOption *statusCodeOption;
//Search for the Status Code option
option = dhcpv6GetOption(options, length, DHCPV6_OPTION_STATUS_CODE);
//If the Status Code option does not appear in a message in which the option
//could appear, the status of the message is assumed to be Success
if(!option || ntohs(option->length) < sizeof(Dhcpv6StatusCodeOption))
return NO_ERROR;
//The option contains a status code and a status message
statusCodeOption = (Dhcpv6StatusCodeOption *) option->value;
//Convert status code from network byte order
statusCode = ntohs(statusCodeOption->statusCode);
//Check the status code returned by the peer
switch(statusCode)
{
//Success
case DHCPV6_STATUS_SUCCESS:
error = NO_ERROR;
break;
//Unspecified failure
case DHCPV6_STATUS_UNSPEC_FAILURE:
error = ERROR_FAILURE;
break;
//Server has no address available to assign to the IA
case DHCPV6_STATUS_NO_ADDRS_AVAILABLE:
error = ERROR_NO_ADDRESS;
break;
//Client record (binding) unavailable
case DHCPV6_STATUS_NO_BINDING:
error = ERROR_NO_BINDING;
break;
//The prefix for the address is not appropriate for
//the link to which the client is attached
case DHCPV6_STATUS_NOT_ON_LINK:
error = ERROR_NOT_ON_LINK;
break;
//Sent by a server to a client to force the client to send
//messages to the server using the multicast address
case DHCPV6_STATUS_USE_MULTICAST:
error = ERROR_USE_MULTICAST;
break;
//Any other failure...
default:
error = ERROR_FAILURE;
break;
}
//Return the corresponding error
return error;
}
error_t dhcpv6ForwardRelayReplyMessage(Dhcpv6RelayCtx *context)
{
error_t error;
uint_t i;
uint32_t interfaceId;
size_t inputMessageLen;
size_t outputMessageLen;
Dhcpv6RelayMessage *inputMessage;
Dhcpv6Message *outputMessage;
Dhcpv6Option *option;
IpAddr ipAddr;
uint16_t port;
//Point to the buffer where to store the incoming DHCPv6 message
inputMessage = (Dhcpv6RelayMessage *) context->buffer;
//Read incoming message
error = socketReceiveFrom(context->serverSocket, &ipAddr, &port,
inputMessage, DHCPV6_MAX_MSG_SIZE, &inputMessageLen, 0);
//Any error to report?
if(error) return error;
//Debug message
TRACE_INFO("\r\nDHCPv6 message received on network-facing interface %s (%" PRIuSIZE " bytes)...\r\n",
context->serverInterface->name, inputMessageLen);
//Dump the contents of the message for debugging purpose
dhcpv6DumpMessage(inputMessage, inputMessageLen);
//Check the length of the DHCPv6 message
if(inputMessageLen < sizeof(Dhcpv6RelayMessage))
return ERROR_INVALID_MESSAGE;
//Inspect the message type and only forward Relay-Reply messages.
//Other DHCPv6 message types must be silently discarded
if(inputMessage->msgType != DHCPV6_MSG_TYPE_RELAY_REPL)
return ERROR_INVALID_MESSAGE;
//Get the length of the Options field
inputMessageLen -= sizeof(Dhcpv6Message);
//Check whether an Interface ID option is included in the Relay-Reply
option = dhcpv6GetOption(inputMessage->options, inputMessageLen, DHCPV6_OPTION_INTERFACE_ID);
//Failed to retrieve specified option?
if(!option || ntohs(option->length) != sizeof(interfaceId))
return ERROR_INVALID_MESSAGE;
//Read the Interface ID option contents
memcpy(&interfaceId, option->value, sizeof(interfaceId));
//Convert the 32-bit integer from network byte order
interfaceId = ntohl(interfaceId);
//The Relay-Reply message must include a Relay Message option
option = dhcpv6GetOption(inputMessage->options, inputMessageLen, DHCPV6_OPTION_RELAY_MSG);
//Failed to retrieve specified option?
if(!option || ntohs(option->length) < sizeof(Dhcpv6Message))
return ERROR_INVALID_MESSAGE;
//Extract the message from the Relay Message option
outputMessage = (Dhcpv6Message *) option->value;
//Save the length of the message
outputMessageLen = ntohs(option->length);
//Loop through client-facing interfaces
for(i = 0; i < context->clientInterfaceCount; i++)
{
//Check whether the current interface matches the Interface ID option
if(context->clientInterface[i]->id == interfaceId)
{
//Debug message
TRACE_INFO("Forwarding DHCPv6 message on client-facing interface %s (%" PRIuSIZE " bytes)...\r\n",
context->clientInterface[i]->name, outputMessageLen);
//Dump the contents of the message for debugging purpose
dhcpv6DumpMessage(outputMessage, outputMessageLen);
//Copy the peer-address into the destination IP address
ipAddr.length = sizeof(Ipv6Addr);
ipAddr.ipv6Addr = inputMessage->peerAddress;
//Select the relevant port number to use
if(outputMessage->msgType == DHCPV6_MSG_TYPE_RELAY_REPL)
port = DHCPV6_SERVER_PORT;
else
port = DHCPV6_CLIENT_PORT;
//Relay the DHCPv6 message to the client on the link
//identified by the Interface ID option
return socketSendTo(context->clientSocket[i], &ipAddr,
port, outputMessage, outputMessageLen, NULL, 0);
}
}
//Unknown interface identifier...
return ERROR_INVALID_OPTION;
}
