void nbnsProcessMessage(NetInterface *interface, const IpPseudoHeader *pseudoHeader,
const UdpHeader *udpHeader, const NetBuffer *buffer, size_t offset, void *params)
{
size_t length;
NbnsHeader *message;
//Make sure the NBNS message was received from an IPv4 peer
if(pseudoHeader->length != sizeof(Ipv4PseudoHeader))
return;
//Retrieve the length of the NBNS message
length = netBufferGetLength(buffer) - offset;
//Ensure the NBNS message is valid
if(length < sizeof(NbnsHeader))
return;
if(length > DNS_MESSAGE_MAX_SIZE)
return;
//Point to the NBNS message header
message = netBufferAt(buffer, offset);
//Sanity check
if(message == NULL)
return;
//Debug message
TRACE_INFO("NBNS message received (%" PRIuSIZE " bytes)...\r\n", length);
//Dump message
dnsDumpMessage((DnsHeader *) message, length);
//NBNS messages received with an opcode other than zero must be silently ignored
if(message->opcode != DNS_OPCODE_QUERY)
return;
//NBNS messages received with non-zero response codes must be silently ignored
if(message->rcode != DNS_RCODE_NO_ERROR)
return;
//NBNS query received?
if(!message->qr)
{
#if (NBNS_RESPONDER_SUPPORT == ENABLED)
//Process incoming NBNS query message
nbnsProcessQuery(interface, &pseudoHeader->ipv4Data,
udpHeader, message, length);
#endif
}
//NBNS response received?
else
{
#if (NBNS_CLIENT_SUPPORT == ENABLED)
//Process incoming NBNS response message
nbnsProcessResponse(interface, &pseudoHeader->ipv4Data,
udpHeader, message, length);
#endif
}
}
error_t pppSendEchoRep(PppContext *context,
const PppEchoPacket *echoReqPacket, PppProtocol protocol)
{
error_t error;
size_t length;
size_t offset;
NetBuffer *buffer;
PppEchoPacket *echoRepPacket;
//Retrieve the length of the Echo-Request packet
length = ntohs(echoReqPacket->length);
//Make sure the length is valid
if(length < sizeof(PppEchoPacket))
return ERROR_INVALID_LENGTH;
if(length > context->peerConfig.mru)
return ERROR_INVALID_LENGTH;
//Allocate a buffer memory to hold the Echo-Reply packet
buffer = pppAllocBuffer(sizeof(PppEchoPacket), &offset);
//Failed to allocate memory?
if(!buffer) return ERROR_OUT_OF_MEMORY;
//Point to the Echo-Reply packet
echoRepPacket = netBufferAt(buffer, offset);
//Format packet header
echoRepPacket->code = PPP_CODE_CODE_REJ;
echoRepPacket->identifier = echoReqPacket->identifier;
echoRepPacket->length = htons(length);
echoRepPacket->magicNumber = context->localConfig.magicNumber;
//The data field of the Echo-Request packet is copied into the data
//field of the Echo-Reply packet
error = netBufferAppend(buffer, echoReqPacket->data, length - sizeof(PppEchoPacket));
//Check status code
if(!error)
{
//Debug message
TRACE_INFO("Sending Echo-Reply packet (%" PRIuSIZE " bytes)...\r\n", length);
//Send PPP frame
error = pppSendFrame(context->interface, buffer, offset, protocol);
}
//Free previously allocated memory block
netBufferFree(buffer);
//Return status code
return error;
}
error_t pppSendProtocolRej(PppContext *context, uint8_t identifier,
uint16_t protocol, const uint8_t *information, size_t length)
{
error_t error;
size_t offset;
NetBuffer *buffer;
PppProtocolRejPacket *protocolRejPacket;
//Calculate the length of the Protocol-Reject packet
length += sizeof(PppProtocolRejPacket);
//The Rejected-Information must be truncated to comply with
//the peer's established MRU
length = MIN(length, context->peerConfig.mru);
//Allocate a buffer memory to hold the Protocol-Reject packet
buffer = pppAllocBuffer(sizeof(PppProtocolRejPacket), &offset);
//Failed to allocate memory?
if(!buffer) return ERROR_OUT_OF_MEMORY;
//Point to the Protocol-Reject packet
protocolRejPacket = netBufferAt(buffer, offset);
//Format packet header
protocolRejPacket->code = PPP_CODE_PROTOCOL_REJ;
protocolRejPacket->identifier = identifier;
protocolRejPacket->length = htons(length);
protocolRejPacket->rejectedProtocol = htons(protocol);
//The Rejected-Information field contains a copy of the
//packet which is being rejected
error = netBufferAppend(buffer, information,
length - sizeof(PppProtocolRejPacket));
//Check status code
if(!error)
{
//Debug message
TRACE_INFO("Sending Protocol-Reject packet (%" PRIuSIZE " bytes)...\r\n", length);
//Send PPP frame
error = pppSendFrame(context->interface, buffer, offset, PPP_PROTOCOL_LCP);
}
//Free previously allocated memory block
netBufferFree(buffer);
//Return status code
return error;
}
error_t chapSendResponse(PppContext *context, const uint8_t *value)
{
error_t error;
size_t n;
size_t length;
size_t offset;
NetBuffer *buffer;
ChapResponsePacket *responsePacket;
//Retrieve the length of the username
n = strlen(context->username);
//Calculate the length of the Response packet
length = sizeof(ChapResponsePacket) + MD5_DIGEST_SIZE + n;
//Allocate a buffer memory to hold the Response packet
buffer = pppAllocBuffer(length, &offset);
//Failed to allocate memory?
if(!buffer) return ERROR_OUT_OF_MEMORY;
//Point to the Response packet
responsePacket = netBufferAt(buffer, offset);
//Format packet header
responsePacket->code = CHAP_CODE_RESPONSE;
responsePacket->identifier = context->chapFsm.peerIdentifier;
responsePacket->length = htons(length);
responsePacket->valueSize = MD5_DIGEST_SIZE;
//Copy the Response value
memcpy(responsePacket->value, value, MD5_DIGEST_SIZE);
//The Name field is one or more octets representing the
//identification of the system transmitting the packet
memcpy(responsePacket->value + MD5_DIGEST_SIZE, context->username, n);
//Debug message
TRACE_INFO("Sending CHAP Response packet (%" PRIuSIZE " bytes)...\r\n", length);
//Dump packet contents for debugging purpose
pppDumpPacket((PppPacket *) responsePacket, length, PPP_PROTOCOL_CHAP);
//Send PPP frame
error = pppSendFrame(context->interface, buffer, offset, PPP_PROTOCOL_CHAP);
//Free previously allocated memory block
netBufferFree(buffer);
//Return status code
return error;
}
NetBuffer *mdnsCreateResponse(uint16_t id, size_t *offset,
DnsHeader **response, size_t *responseLen)
{
NetBuffer *buffer;
DnsHeader *header;
//Allocate a memory buffer to hold the mDNS message
buffer = udpAllocBuffer(MDNS_MESSAGE_MAX_SIZE, offset);
//Successful memory allocation?
if(buffer != NULL)
{
//Point to the mDNS response header
header = netBufferAt(buffer, *offset);
//Take the identifier from the query message
header->id = id;
//Format mDNS response header
header->qr = 1;
header->opcode = DNS_OPCODE_QUERY;
header->aa = 1;
header->tc = 0;
header->rd = 0;
header->ra = 0;
header->z = 0;
header->rcode = DNS_RCODE_NO_ERROR;
//Multicast DNS responses must not contain any questions
header->qdcount = 0;
header->ancount = 0;
header->nscount = 0;
header->arcount = 0;
//Pointer to the mDNS response header
*response = header;
//Actual length of the mDNS response message
*responseLen = sizeof(DnsHeader);
}
//Return a pointer to the buffer that holds the mDNS message
return buffer;
}
error_t pppSendTerminateAck(PppContext *context,
uint8_t identifier, PppProtocol protocol)
{
error_t error;
size_t length;
size_t offset;
NetBuffer *buffer;
PppTerminatePacket *terminateAckPacket;
//Length of the Terminate-Ack packet
length = sizeof(PppTerminatePacket);
//Allocate a buffer memory to hold the Terminate-Ack packet
buffer = pppAllocBuffer(length, &offset);
//Failed to allocate memory?
if(!buffer) return ERROR_OUT_OF_MEMORY;
//Point to the Terminate-Ack packet
terminateAckPacket = netBufferAt(buffer, offset);
//Format packet header
terminateAckPacket->code = PPP_CODE_TERMINATE_ACK;
terminateAckPacket->identifier = identifier;
terminateAckPacket->length = htons(length);
//Debug message
TRACE_INFO("Sending Terminate-Ack packet (%" PRIuSIZE " bytes)...\r\n", length);
//Dump packet contents for debugging purpose
pppDumpPacket((PppPacket *) terminateAckPacket, length, protocol);
//Send PPP frame
error = pppSendFrame(context->interface, buffer, offset, protocol);
//Free previously allocated memory block
netBufferFree(buffer);
//Return status code
return error;
}
error_t chapSendFailure(PppContext *context)
{
error_t error;
size_t length;
size_t offset;
NetBuffer *buffer;
PppPacket *failurePacket;
//Retrieve the length of the Failure packet
length = sizeof(PppPacket);
//Allocate a buffer memory to hold the Failure packet
buffer = pppAllocBuffer(length, &offset);
//Failed to allocate memory?
if(!buffer) return ERROR_OUT_OF_MEMORY;
//Point to the Failure packet
failurePacket = netBufferAt(buffer, offset);
//Format packet header
failurePacket->code = CHAP_CODE_FAILURE;
failurePacket->identifier = context->chapFsm.localIdentifier;
failurePacket->length = htons(length);
//Debug message
TRACE_INFO("Sending CHAP Failure packet (%" PRIuSIZE " bytes)...\r\n", length);
//Dump packet contents for debugging purpose
pppDumpPacket((PppPacket *) failurePacket, length, PPP_PROTOCOL_CHAP);
//Send PPP frame
error = pppSendFrame(context->interface, buffer, offset, PPP_PROTOCOL_CHAP);
//Free previously allocated memory block
netBufferFree(buffer);
//Return status code
return error;
}
error_t mdnsSendAnnouncement(NetInterface *interface)
{
error_t error;
size_t length;
size_t offset;
NetBuffer *buffer;
DnsHeader *message;
IpAddr destIpAddr;
//Initialize error code
error = NO_ERROR;
//Allocate a memory buffer to hold the mDNS query message
buffer = udpAllocBuffer(DNS_MESSAGE_MAX_SIZE, &offset);
//Failed to allocate buffer?
if(!buffer) return ERROR_OUT_OF_MEMORY;
//Point to the mDNS header
message = netBufferAt(buffer, offset);
//Format mDNS query message
message->id = 0;
message->qr = 1;
message->opcode = DNS_OPCODE_QUERY;
message->aa = 1;
message->tc = 0;
message->rd = 0;
message->ra = 0;
message->z = 0;
message->rcode = DNS_RCODE_NO_ERROR;
//Multicast DNS responses must not contain any questions
message->qdcount = 0;
message->ancount = 0;
message->nscount = 0;
message->arcount = 0;
//Length of the mDNS query message
length = sizeof(DnsHeader);
//Start of exception handling block
do
{
//Format A resource record
error = mdnsAddIpv4ResourceRecord(interface, message, &length, TRUE);
//Any error to report?
if(error) break;
//Format AAAA resource record
error = mdnsAddIpv6ResourceRecord(interface, message, &length, TRUE);
//Any error to report?
if(error) break;
//Convert 16-bit value to network byte order
message->ancount = htons(message->ancount);
//Adjust the length of the multi-part buffer
netBufferSetLength(buffer, offset + length);
//Debug message
TRACE_INFO("Sending mDNS announcement (%" PRIuSIZE " bytes)...\r\n", length);
//Dump message
dnsDumpMessage(message, length);
#if (IPV4_SUPPORT == ENABLED)
//Select the relevant multicast address (224.0.0.251)
destIpAddr.length = sizeof(Ipv4Addr);
destIpAddr.ipv4Addr = MDNS_IPV4_MULTICAST_ADDR;
//All multicast DNS queries should be sent with an IP TTL set to 255
error = udpSendDatagramEx(interface, MDNS_PORT, &destIpAddr,
MDNS_PORT, buffer, offset, MDNS_DEFAULT_IP_TTL);
//Any error to report?
if(error)break;
#endif
#if (IPV6_SUPPORT == ENABLED)
//Select the relevant multicast address (ff02::fb)
destIpAddr.length = sizeof(Ipv6Addr);
destIpAddr.ipv6Addr = MDNS_IPV6_MULTICAST_ADDR;
//All multicast DNS queries should be sent with an IP TTL set to 255
error = udpSendDatagramEx(interface, MDNS_PORT, &destIpAddr,
MDNS_PORT, buffer, offset, MDNS_DEFAULT_IP_TTL);
//Any error to report?
if(error)break;
#endif
//End of exception handling block
} while(0);
//Free previously allocated memory
netBufferFree(buffer);
//Return status code
return error;
}
error_t mdnsSendProbe(NetInterface *interface)
{
error_t error;
size_t length;
size_t offset;
NetBuffer *buffer;
DnsHeader *message;
DnsQuestion *dnsQuestion;
IpAddr destIpAddr;
//Initialize error code
error = NO_ERROR;
//Allocate a memory buffer to hold the mDNS query message
buffer = udpAllocBuffer(DNS_MESSAGE_MAX_SIZE, &offset);
//Failed to allocate buffer?
if(!buffer) return ERROR_OUT_OF_MEMORY;
//Point to the mDNS header
message = netBufferAt(buffer, offset);
//Format mDNS query message
message->id = 0;
message->qr = 0;
message->opcode = DNS_OPCODE_QUERY;
message->aa = 0;
message->tc = 0;
message->rd = 0;
message->ra = 0;
message->z = 0;
message->rcode = DNS_RCODE_NO_ERROR;
//The mDNS query contains one question
message->qdcount = HTONS(1);
message->ancount = 0;
message->nscount = 0;
message->arcount = 0;
//Length of the mDNS query message
length = sizeof(DnsHeader);
//Encode the host name using the DNS name notation
length += mdnsEncodeName(interface->hostname, "",
".local", (uint8_t *) message + length);
//Point to the corresponding question structure
dnsQuestion = DNS_GET_QUESTION(message, length);
//Fill in question structure
dnsQuestion->qtype = HTONS(DNS_RR_TYPE_ANY);
dnsQuestion->qclass = HTONS(DNS_RR_CLASS_IN);
//Update the length of the mDNS query message
length += sizeof(DnsQuestion);
//Adjust the length of the multi-part buffer
netBufferSetLength(buffer, offset + length);
//Debug message
TRACE_INFO("Sending mDNS probe (%" PRIuSIZE " bytes)...\r\n", length);
//Dump message
dnsDumpMessage(message, length);
#if (IPV4_SUPPORT == ENABLED)
//Check status code
if(!error)
{
//Select the relevant multicast address (224.0.0.251)
destIpAddr.length = sizeof(Ipv4Addr);
destIpAddr.ipv4Addr = MDNS_IPV4_MULTICAST_ADDR;
//All multicast DNS queries should be sent with an IP TTL set to 255
error = udpSendDatagramEx(interface, MDNS_PORT, &destIpAddr,
MDNS_PORT, buffer, offset, MDNS_DEFAULT_IP_TTL);
}
#endif
#if (IPV6_SUPPORT == ENABLED)
//Check status code
if(!error)
{
//Select the relevant multicast address (ff02::fb)
destIpAddr.length = sizeof(Ipv6Addr);
destIpAddr.ipv6Addr = MDNS_IPV6_MULTICAST_ADDR;
//All multicast DNS queries should be sent with an IP TTL set to 255
error = udpSendDatagramEx(interface, MDNS_PORT, &destIpAddr,
MDNS_PORT, buffer, offset, MDNS_DEFAULT_IP_TTL);
}
#endif
//Free previously allocated memory
netBufferFree(buffer);
//Return status code
return error;
}
error_t lcpSendConfigureReq(PppContext *context)
{
error_t error;
size_t length;
size_t offset;
NetBuffer *buffer;
PppConfigurePacket *configureReqPacket;
//Debug message
TRACE_INFO("LCP Send-Configure-Request callback\r\n");
//Calculate the maximum size of the Configure-Request packet
length = sizeof(PppConfigurePacket) +
sizeof(LcpMruOption) + sizeof(LcpAccmOption);
//Allocate a buffer memory to hold the packet
buffer = pppAllocBuffer(length, &offset);
//Failed to allocate memory?
if(!buffer) return ERROR_OUT_OF_MEMORY;
//Point to the Configure-Request packet
configureReqPacket = netBufferAt(buffer, offset);
//Format packet header
configureReqPacket->code = PPP_CODE_CONFIGURE_REQ;
configureReqPacket->identifier = ++context->lcpFsm.identifier;
configureReqPacket->length = sizeof(PppConfigurePacket);
//Make sure the Maximum-Receive-Unit option has not been previously rejected
if(!context->localConfig.mruRejected)
{
//Convert MRU to network byte order
uint16_t value = htons(context->localConfig.mru);
//Add option
pppAddOption(configureReqPacket, LCP_OPTION_MRU, &value, sizeof(uint16_t));
}
//Make sure the Async-Control-Character-Map option has not been previously rejected
if(!context->localConfig.accmRejected)
{
//Convert ACCM to network byte order
uint32_t value = htonl(context->localConfig.accm);
//Add option
pppAddOption(configureReqPacket, LCP_OPTION_ACCM, &value, sizeof(uint32_t));
}
//Save packet length
length = configureReqPacket->length;
//Convert length field to network byte order
configureReqPacket->length = htons(length);
//Adjust the length of the multi-part buffer
netBufferSetLength(buffer, offset + length);
//Debug message
TRACE_INFO("Sending Configure-Request packet (%" PRIuSIZE " bytes)...\r\n", length);
//Dump packet contents for debugging purpose
pppDumpPacket((PppPacket *) configureReqPacket, length, PPP_PROTOCOL_LCP);
//Send PPP frame
error = pppSendFrame(context->interface, buffer, offset, PPP_PROTOCOL_LCP);
//The restart counter is decremented each time a Configure-Request is sent
if(context->lcpFsm.restartCounter > 0)
context->lcpFsm.restartCounter--;
//Save the time at which the packet was sent
context->lcpFsm.timestamp = osGetSystemTime();
//Free previously allocated memory block
netBufferFree(buffer);
//Return status code
return error;
}
void dnsProcessResponse(NetInterface *interface, const IpPseudoHeader *pseudoHeader,
const UdpHeader *udpHeader, const NetBuffer *buffer, size_t offset, void *params)
{
uint_t i;
uint_t j;
size_t pos;
size_t length;
DnsHeader *message;
DnsQuestion *question;
DnsResourceRecord *resourceRecord;
DnsCacheEntry *entry;
//Retrieve the length of the DNS message
length = netBufferGetLength(buffer) - offset;
//Ensure the DNS message is valid
if(length < sizeof(DnsHeader))
return;
if(length > DNS_MESSAGE_MAX_SIZE)
return;
//Point to the DNS message header
message = netBufferAt(buffer, offset);
//Sanity check
if(!message) return;
//Debug message
TRACE_INFO("DNS message received (%" PRIuSIZE " bytes)...\r\n", length);
//Dump message
dnsDumpMessage(message, length);
//Check message type
if(!message->qr)
return;
//The DNS message shall contain one question
if(ntohs(message->qdcount) != 1)
return;
//Acquire exclusive access to the DNS cache
osAcquireMutex(&dnsCacheMutex);
//Loop through DNS cache entries
for(i = 0; i < DNS_CACHE_SIZE; i++)
{
//Point to the current entry
entry = &dnsCache[i];
//DNS name resolution in progress?
if(entry->state == DNS_STATE_IN_PROGRESS &&
entry->protocol == HOST_NAME_RESOLVER_DNS)
{
//Check destination port number
if(entry->port == ntohs(udpHeader->destPort))
{
//Compare identifier against the expected one
if(ntohs(message->id) != entry->id)
break;
//Point to the first question
pos = sizeof(DnsHeader);
//Parse domain name
pos = dnsParseName(message, length, pos, NULL, 0);
//Invalid name?
if(!pos)
break;
//Malformed mDNS message?
if((pos + sizeof(DnsQuestion)) > length)
break;
//Compare domain name
if(!dnsCompareName(message, length, sizeof(DnsHeader), entry->name, 0))
break;
//Point to the corresponding entry
question = DNS_GET_QUESTION(message, pos);
//Check the class of the query
if(ntohs(question->qclass) != DNS_RR_CLASS_IN)
break;
//Check the type of the query
if(entry->type == HOST_TYPE_IPV4 && ntohs(question->qtype) != DNS_RR_TYPE_A)
break;
if(entry->type == HOST_TYPE_IPV6 && ntohs(question->qtype) != DNS_RR_TYPE_AAAA)
break;
//Make sure recursion is available
if(!message->ra)
{
//The entry should be deleted since name resolution has failed
dnsDeleteEntry(entry);
//Exit immediately
break;
}
//Check return code
if(message->rcode != DNS_RCODE_NO_ERROR)
{
//The entry should be deleted since name resolution has failed
dnsDeleteEntry(entry);
//Exit immediately
break;
}
//Point to the first answer
pos += sizeof(DnsQuestion);
//Parse answer resource records
for(j = 0; j < ntohs(message->ancount); j++)
{
//Parse domain name
pos = dnsParseName(message, length, pos, NULL, 0);
//Invalid name?
if(!pos) break;
//Point to the associated resource record
resourceRecord = DNS_GET_RESOURCE_RECORD(message, pos);
//Point to the resource data
pos += sizeof(DnsResourceRecord);
//Make sure the resource record is valid
if(pos > length)
break;
if((pos + ntohs(resourceRecord->rdlength)) > length)
break;
#if (IPV4_SUPPORT == ENABLED)
//IPv4 address expected?
if(entry->type == HOST_TYPE_IPV4)
{
//A resource record found?
if(ntohs(resourceRecord->rtype) == DNS_RR_TYPE_A &&
ntohs(resourceRecord->rdlength) == sizeof(Ipv4Addr))
{
//Copy the IPv4 address
entry->ipAddr.length = sizeof(Ipv4Addr);
ipv4CopyAddr(&entry->ipAddr.ipv4Addr, resourceRecord->rdata);
//Save current time
entry->timestamp = osGetSystemTime();
//Save TTL value
entry->timeout = ntohl(resourceRecord->ttl) * 1000;
//Limit the lifetime of the DNS cache entries
entry->timeout = MIN(entry->timeout, DNS_MAX_LIFETIME);
//Unregister UDP callback function
udpDetachRxCallback(interface, entry->port);
//Host name successfully resolved
entry->state = DNS_STATE_RESOLVED;
//Exit immediately
break;
}
}
#endif
#if (IPV6_SUPPORT == ENABLED)
//IPv6 address expected?
if(entry->type == HOST_TYPE_IPV6)
{
//AAAA resource record found?
if(ntohs(resourceRecord->rtype) == DNS_RR_TYPE_AAAA &&
ntohs(resourceRecord->rdlength) == sizeof(Ipv6Addr))
{
//Copy the IPv6 address
entry->ipAddr.length = sizeof(Ipv6Addr);
ipv6CopyAddr(&entry->ipAddr.ipv6Addr, resourceRecord->rdata);
//Save current time
entry->timestamp = osGetSystemTime();
//Save TTL value
entry->timeout = ntohl(resourceRecord->ttl) * 1000;
//Limit the lifetime of the DNS cache entries
entry->timeout = MIN(entry->timeout, DNS_MAX_LIFETIME);
//Unregister UDP callback function
udpDetachRxCallback(interface, entry->port);
//Host name successfully resolved
entry->state = DNS_STATE_RESOLVED;
//Exit immediately
break;
}
}
#endif
//Point to the next resource record
pos += ntohs(resourceRecord->rdlength);
}
//We are done
break;
}
}
}
//Release exclusive access to the DNS cache
osReleaseMutex(&dnsCacheMutex);
}
Ipv4FragDesc *ipv4SearchFragQueue(NetInterface *interface, const Ipv4Header *packet)
{
error_t error;
uint_t i;
Ipv4Header *datagram;
Ipv4FragDesc *frag;
Ipv4HoleDesc *hole;
//Search for a matching IP datagram being reassembled
for(i = 0; i < IPV4_MAX_FRAG_DATAGRAMS; i++)
{
//Point to the current entry in the reassembly queue
frag = &interface->ipv4FragQueue[i];
//Check whether the current entry is used?
if(frag->buffer.chunkCount > 0)
{
//Point to the corresponding datagram
datagram = netBufferAt((NetBuffer *) &frag->buffer, 0);
//Check source and destination addresses
if(datagram->srcAddr != packet->srcAddr)
continue;
if(datagram->destAddr != packet->destAddr)
continue;
//Compare identification and protocol fields
if(datagram->identification != packet->identification)
continue;
if(datagram->protocol != packet->protocol)
continue;
//A matching entry has been found in the reassembly queue
return frag;
}
}
//If the current packet does not match an existing entry
//in the reassembly queue, then create a new entry
for(i = 0; i < IPV4_MAX_FRAG_DATAGRAMS; i++)
{
//Point to the current entry in the reassembly queue
frag = &interface->ipv4FragQueue[i];
//The current entry is free?
if(!frag->buffer.chunkCount)
{
//Number of chunks that comprise the reassembly buffer
frag->buffer.maxChunkCount = arraysize(frag->buffer.chunk);
//Allocate sufficient memory to hold the IPv4 header and
//the first hole descriptor
error = netBufferSetLength((NetBuffer *) &frag->buffer,
NET_MEM_POOL_BUFFER_SIZE + sizeof(Ipv4HoleDesc));
//Failed to allocate memory?
if(error)
{
//Clean up side effects
netBufferSetLength((NetBuffer *) &frag->buffer, 0);
//Exit immediately
return NULL;
}
//Initial length of the reconstructed datagram
frag->headerLength = packet->headerLength * 4;
frag->dataLength = 0;
//Fix the length of the first chunk
frag->buffer.chunk[0].length = frag->headerLength;
//Copy IPv4 header from the incoming fragment
netBufferWrite((NetBuffer *) &frag->buffer, 0, packet, frag->headerLength);
//Save current time
frag->timestamp = osGetSystemTime();
//Create a new entry in the hole descriptor list
frag->firstHole = 0;
//Point to first hole descriptor
hole = ipv4FindHole(frag, frag->firstHole);
//The entry describes the datagram as being completely missing
hole->first = 0;
hole->last = IPV4_INFINITY;
hole->next = IPV4_INFINITY;
//Dump hole descriptor list
ipv4DumpHoleList(frag);
//Return the matching fragment descriptor
return frag;
}
}
//The reassembly queue is full
return NULL;
}
error_t udpProcessDatagram(NetInterface *interface,
IpPseudoHeader *pseudoHeader, const NetBuffer *buffer, size_t offset)
{
error_t error;
uint_t i;
size_t length;
UdpHeader *header;
Socket *socket;
SocketQueueItem *queueItem;
NetBuffer *p;
//Retrieve the length of the UDP datagram
length = netBufferGetLength(buffer) - offset;
//Ensure the UDP header is valid
if(length < sizeof(UdpHeader))
{
//Debug message
TRACE_WARNING("UDP datagram length is invalid!\r\n");
//Report an error
return ERROR_INVALID_HEADER;
}
//Point to the UDP header
header = netBufferAt(buffer, offset);
//Sanity check
if(!header) return ERROR_FAILURE;
//Debug message
TRACE_INFO("UDP datagram received (%" PRIuSIZE " bytes)...\r\n", length);
//Dump UDP header contents for debugging purpose
udpDumpHeader(header);
//When UDP runs over IPv6, the checksum is mandatory
if(header->checksum || pseudoHeader->length == sizeof(Ipv6PseudoHeader))
{
//Verify UDP checksum
if(ipCalcUpperLayerChecksumEx(pseudoHeader->data,
pseudoHeader->length, buffer, offset, length) != 0xFFFF)
{
//Debug message
TRACE_WARNING("Wrong UDP header checksum!\r\n");
//Report an error
return ERROR_WRONG_CHECKSUM;
}
}
//Enter critical section
osAcquireMutex(&socketMutex);
//Loop through opened sockets
for(i = 0; i < SOCKET_MAX_COUNT; i++)
{
//Point to the current socket
socket = socketTable + i;
//UDP socket found?
if(socket->type != SOCKET_TYPE_DGRAM)
continue;
//Check whether the socket is bound to a particular interface
if(socket->interface && socket->interface != interface)
continue;
//Check destination port number
if(socket->localPort != ntohs(header->destPort))
continue;
//Source port number filtering
if(socket->remotePort && socket->remotePort != ntohs(header->srcPort))
continue;
#if (IPV4_SUPPORT == ENABLED)
//An IPv4 packet was received?
if(pseudoHeader->length == sizeof(Ipv4PseudoHeader))
{
//Destination IP address filtering
if(socket->localIpAddr.length)
{
//An IPv4 address is expected
if(socket->localIpAddr.length != sizeof(Ipv4Addr))
continue;
//Filter out non-matching addresses
if(socket->localIpAddr.ipv4Addr != pseudoHeader->ipv4Data.destAddr)
continue;
}
//Source IP address filtering
if(socket->remoteIpAddr.length)
{
//An IPv4 address is expected
if(socket->remoteIpAddr.length != sizeof(Ipv4Addr))
continue;
//Filter out non-matching addresses
if(socket->remoteIpAddr.ipv4Addr != pseudoHeader->ipv4Data.srcAddr)
continue;
}
}
else
#endif
#if (IPV6_SUPPORT == ENABLED)
//An IPv6 packet was received?
if(pseudoHeader->length == sizeof(Ipv6PseudoHeader))
{
//Destination IP address filtering
if(socket->localIpAddr.length)
{
//An IPv6 address is expected
if(socket->localIpAddr.length != sizeof(Ipv6Addr))
continue;
//Filter out non-matching addresses
if(!ipv6CompAddr(&socket->localIpAddr.ipv6Addr, &pseudoHeader->ipv6Data.destAddr))
continue;
}
//Source IP address filtering
if(socket->remoteIpAddr.length)
{
//An IPv6 address is expected
if(socket->remoteIpAddr.length != sizeof(Ipv6Addr))
continue;
//Filter out non-matching addresses
if(!ipv6CompAddr(&socket->remoteIpAddr.ipv6Addr, &pseudoHeader->ipv6Data.srcAddr))
continue;
}
}
else
#endif
//An invalid packet was received?
{
//This should never occur...
continue;
}
//The current socket meets all the criteria
break;
}
//Point to the payload
offset += sizeof(UdpHeader);
length -= sizeof(UdpHeader);
//No matching socket found?
if(i >= SOCKET_MAX_COUNT)
{
//Leave critical section
osReleaseMutex(&socketMutex);
//Invoke user callback, if any
error = udpInvokeRxCallback(interface, pseudoHeader, header, buffer, offset);
//Return status code
return error;
}
//Empty receive queue?
if(!socket->receiveQueue)
{
//Allocate a memory buffer to hold the data and the associated descriptor
p = netBufferAlloc(sizeof(SocketQueueItem) + length);
//Successful memory allocation?
if(p != NULL)
{
//Point to the newly created item
queueItem = netBufferAt(p, 0);
queueItem->buffer = p;
//Add the newly created item to the queue
socket->receiveQueue = queueItem;
}
else
{
//Memory allocation failed
queueItem = NULL;
}
}
else
{
//Point to the very first item
queueItem = socket->receiveQueue;
//Reach the last item in the receive queue
for(i = 1; queueItem->next; i++)
queueItem = queueItem->next;
//Make sure the receive queue is not full
if(i >= UDP_RX_QUEUE_SIZE)
{
//Leave critical section
osReleaseMutex(&socketMutex);
//Notify the calling function that the queue is full
return ERROR_RECEIVE_QUEUE_FULL;
}
//Allocate a memory buffer to hold the data and the associated descriptor
p = netBufferAlloc(sizeof(SocketQueueItem) + length);
//Successful memory allocation?
if(p != NULL)
{
//Add the newly created item to the queue
queueItem->next = netBufferAt(p, 0);
//Point to the newly created item
queueItem = queueItem->next;
queueItem->buffer = p;
}
else
{
//Memory allocation failed
queueItem = NULL;
}
}
//Failed to allocate memory?
if(!queueItem)
{
//Leave critical section
osReleaseMutex(&socketMutex);
//Return error code
return ERROR_OUT_OF_MEMORY;
}
//Initialize next field
queueItem->next = NULL;
//Record the source port number
queueItem->srcPort = ntohs(header->srcPort);
#if (IPV4_SUPPORT == ENABLED)
//IPv4 remote address?
if(pseudoHeader->length == sizeof(Ipv4PseudoHeader))
{
//Save the source IPv4 address
queueItem->srcIpAddr.length = sizeof(Ipv4Addr);
queueItem->srcIpAddr.ipv4Addr = pseudoHeader->ipv4Data.srcAddr;
//Save the destination IPv4 address
queueItem->destIpAddr.length = sizeof(Ipv4Addr);
queueItem->destIpAddr.ipv4Addr = pseudoHeader->ipv4Data.destAddr;
}
#endif
#if (IPV6_SUPPORT == ENABLED)
//IPv6 remote address?
if(pseudoHeader->length == sizeof(Ipv6PseudoHeader))
{
//Save the source IPv6 address
queueItem->srcIpAddr.length = sizeof(Ipv6Addr);
queueItem->srcIpAddr.ipv6Addr = pseudoHeader->ipv6Data.srcAddr;
//Save the destination IPv6 address
queueItem->destIpAddr.length = sizeof(Ipv6Addr);
queueItem->destIpAddr.ipv6Addr = pseudoHeader->ipv6Data.destAddr;
}
#endif
//Offset to the payload
queueItem->offset = sizeof(SocketQueueItem);
//Copy the payload
netBufferCopy(queueItem->buffer, queueItem->offset, buffer, offset, length);
//Notify user that data is available
udpUpdateEvents(socket);
//Leave critical section
osReleaseMutex(&socketMutex);
//Successful processing
return NO_ERROR;
}
error_t chapSendChallenge(PppContext *context)
{
error_t error;
size_t n;
size_t length;
size_t offset;
NetBuffer *buffer;
ChapChallengePacket *challengePacket;
//Retrieve the length of the username
n = strlen(context->username);
//Calculate the length of the Challenge packet
length = sizeof(ChapChallengePacket) + MD5_DIGEST_SIZE + n;
//Allocate a buffer memory to hold the Challenge packet
buffer = pppAllocBuffer(length, &offset);
//Failed to allocate memory?
if(!buffer) return ERROR_OUT_OF_MEMORY;
//Point to the Challenge packet
challengePacket = netBufferAt(buffer, offset);
//Format packet header
challengePacket->code = CHAP_CODE_CHALLENGE;
challengePacket->identifier = ++context->chapFsm.localIdentifier;
challengePacket->length = htons(length);
challengePacket->valueSize = MD5_DIGEST_SIZE;
//Make sure that the callback function has been registered
if(context->settings.randCallback != NULL)
{
//Generate a random challenge value
error = context->settings.randCallback(
context->chapFsm.challenge, MD5_DIGEST_SIZE);
}
else
{
//Report an error
error = ERROR_FAILURE;
}
//Check status code
if(!error)
{
//Copy the challenge value
memcpy(challengePacket->value, context->chapFsm.challenge, MD5_DIGEST_SIZE);
//The Name field is one or more octets representing the
//identification of the system transmitting the packet
memcpy(challengePacket->value + MD5_DIGEST_SIZE, context->username, n);
//Debug message
TRACE_INFO("Sending CHAP Challenge packet (%" PRIuSIZE " bytes)...\r\n", length);
//Dump packet contents for debugging purpose
pppDumpPacket((PppPacket *) challengePacket, length, PPP_PROTOCOL_CHAP);
//Send PPP frame
error = pppSendFrame(context->interface, buffer, offset, PPP_PROTOCOL_CHAP);
//The restart counter is decremented each time a Challenge packet is sent
if(context->chapFsm.restartCounter > 0)
context->chapFsm.restartCounter--;
//Save the time at which the packet was sent
context->chapFsm.timestamp = osGetSystemTime();
}
//Free previously allocated memory block
netBufferFree(buffer);
//Return status code
return error;
}
void tcpProcessSegment(NetInterface *interface,
IpPseudoHeader *pseudoHeader, const NetBuffer *buffer, size_t offset)
{
uint_t i;
size_t length;
Socket *socket;
Socket *passiveSocket;
TcpHeader *segment;
//Total number of segments received, including those received in error
MIB2_INC_COUNTER32(mib2Base.tcpGroup.tcpInSegs, 1);
MIB2_INC_COUNTER64(mib2Base.tcpGroup.tcpHCInSegs, 1);
//A TCP implementation must silently discard an incoming
//segment that is addressed to a broadcast or multicast
//address (see RFC 1122 4.2.3.10)
#if (IPV4_SUPPORT == ENABLED)
if(pseudoHeader->length == sizeof(Ipv4PseudoHeader))
{
//Ensure the destination address is not a broadcast address
if(ipv4IsBroadcastAddr(interface, pseudoHeader->ipv4Data.destAddr))
return;
//Ensure the destination address is not a multicast address
if(ipv4IsMulticastAddr(pseudoHeader->ipv4Data.destAddr))
return;
}
else
#endif
#if (IPV6_SUPPORT == ENABLED)
if(pseudoHeader->length == sizeof(Ipv6PseudoHeader))
{
//Ensure the destination address is not a multicast address
if(ipv6IsMulticastAddr(&pseudoHeader->ipv6Data.destAddr))
return;
}
else
#endif
{
//This should never occur...
return;
}
//Retrieve the length of the TCP segment
length = netBufferGetLength(buffer) - offset;
//Point to the TCP header
segment = netBufferAt(buffer, offset);
//Sanity check
if(segment == NULL)
return;
//Ensure the TCP header is valid
if(length < sizeof(TcpHeader))
{
//Debug message
TRACE_WARNING("TCP segment length is invalid!\r\n");
//Total number of segments received in error
MIB2_INC_COUNTER32(mib2Base.tcpGroup.tcpInErrs, 1);
//Exit immediately
return;
}
//Check header length
if(segment->dataOffset < 5 || (segment->dataOffset * 4) > length)
{
//Debug message
TRACE_WARNING("TCP header length is invalid!\r\n");
//Total number of segments received in error
MIB2_INC_COUNTER32(mib2Base.tcpGroup.tcpInErrs, 1);
//Exit immediately
return;
}
//Verify TCP checksum
if(ipCalcUpperLayerChecksumEx(pseudoHeader->data,
pseudoHeader->length, buffer, offset, length) != 0x0000)
{
//Debug message
TRACE_WARNING("Wrong TCP header checksum!\r\n");
//Total number of segments received in error
MIB2_INC_COUNTER32(mib2Base.tcpGroup.tcpInErrs, 1);
//Exit immediately
return;
}
//No matching socket in the LISTEN state for the moment
passiveSocket = NULL;
//Look through opened sockets
for(i = 0; i < SOCKET_MAX_COUNT; i++)
{
//Point to the current socket
socket = socketTable + i;
//TCP socket found?
if(socket->type != SOCKET_TYPE_STREAM)
continue;
//Check whether the socket is bound to a particular interface
if(socket->interface && socket->interface != interface)
continue;
//Check destination port number
if(socket->localPort != ntohs(segment->destPort))
continue;
#if (IPV4_SUPPORT == ENABLED)
//An IPv4 packet was received?
if(pseudoHeader->length == sizeof(Ipv4PseudoHeader))
{
//Destination IP address filtering
if(socket->localIpAddr.length)
{
//An IPv4 address is expected
if(socket->localIpAddr.length != sizeof(Ipv4Addr))
continue;
//Filter out non-matching addresses
if(socket->localIpAddr.ipv4Addr != pseudoHeader->ipv4Data.destAddr)
continue;
}
//Source IP address filtering
if(socket->remoteIpAddr.length)
{
//An IPv4 address is expected
if(socket->remoteIpAddr.length != sizeof(Ipv4Addr))
continue;
//Filter out non-matching addresses
if(socket->remoteIpAddr.ipv4Addr != pseudoHeader->ipv4Data.srcAddr)
continue;
}
}
else
#endif
#if (IPV6_SUPPORT == ENABLED)
//An IPv6 packet was received?
if(pseudoHeader->length == sizeof(Ipv6PseudoHeader))
{
//Destination IP address filtering
if(socket->localIpAddr.length)
{
//An IPv6 address is expected
if(socket->localIpAddr.length != sizeof(Ipv6Addr))
continue;
//Filter out non-matching addresses
if(!ipv6CompAddr(&socket->localIpAddr.ipv6Addr, &pseudoHeader->ipv6Data.destAddr))
continue;
}
//Source IP address filtering
if(socket->remoteIpAddr.length)
{
//An IPv6 address is expected
if(socket->remoteIpAddr.length != sizeof(Ipv6Addr))
continue;
//Filter out non-matching addresses
if(!ipv6CompAddr(&socket->remoteIpAddr.ipv6Addr, &pseudoHeader->ipv6Data.srcAddr))
continue;
}
}
else
#endif
//An invalid packet was received?
{
//This should never occur...
continue;
}
//Keep track of the first matching socket in the LISTEN state
if(socket->state == TCP_STATE_LISTEN && !passiveSocket)
passiveSocket = socket;
//Source port filtering
if(socket->remotePort != ntohs(segment->srcPort))
continue;
//A matching socket has been found
break;
}
//If no matching socket has been found then try to
//use the first matching socket in the LISTEN state
if(i >= SOCKET_MAX_COUNT) socket = passiveSocket;
//Offset to the first data byte
offset += segment->dataOffset * 4;
//Calculate the length of the data
length -= segment->dataOffset * 4;
//Debug message
TRACE_DEBUG("%s: TCP segment received (%" PRIuSIZE " data bytes)...\r\n",
formatSystemTime(osGetSystemTime(), NULL), length);
//Dump TCP header contents for debugging purpose
if(!socket)
tcpDumpHeader(segment, length, 0, 0);
else
tcpDumpHeader(segment, length, socket->irs, socket->iss);
//Convert from network byte order to host byte order
segment->srcPort = ntohs(segment->srcPort);
segment->destPort = ntohs(segment->destPort);
segment->seqNum = ntohl(segment->seqNum);
segment->ackNum = ntohl(segment->ackNum);
segment->window = ntohs(segment->window);
segment->urgentPointer = ntohs(segment->urgentPointer);
//Specified port is unreachable?
if(!socket)
{
//An incoming segment not containing a RST causes
//a reset to be sent in response
if(!(segment->flags & TCP_FLAG_RST))
tcpSendResetSegment(interface, pseudoHeader, segment, length);
//Return immediately
return;
}
//Check current state
switch(socket->state)
{
//Process CLOSED state
case TCP_STATE_CLOSED:
//This is the default state that each connection starts in before
//the process of establishing it begins
tcpStateClosed(interface, pseudoHeader, segment, length);
break;
//Process LISTEN state
case TCP_STATE_LISTEN:
//A device (normally a server) is waiting to receive a synchronize (SYN)
//message from a client. It has not yet sent its own SYN message
tcpStateListen(socket, interface, pseudoHeader, segment, length);
break;
//Process SYN_SENT state
case TCP_STATE_SYN_SENT:
//The device (normally a client) has sent a synchronize (SYN) message and
//is waiting for a matching SYN from the other device (usually a server)
tcpStateSynSent(socket, segment, length);
break;
//Process SYN_RECEIVED state
case TCP_STATE_SYN_RECEIVED:
//The device has both received a SYN from its partner and sent its own SYN.
//It is now waiting for an ACK to its SYN to finish connection setup
tcpStateSynReceived(socket, segment, buffer, offset, length);
break;
//Process ESTABLISHED state
case TCP_STATE_ESTABLISHED:
//Data can be exchanged freely once both devices in the connection enter
//this state. This will continue until the connection is closed
tcpStateEstablished(socket, segment, buffer, offset, length);
break;
//Process CLOSE_WAIT state
case TCP_STATE_CLOSE_WAIT:
//The device has received a close request (FIN) from the other device. It
//must now wait for the application to acknowledge this request and
//generate a matching request
tcpStateCloseWait(socket, segment, length);
break;
//Process LAST_ACK state
case TCP_STATE_LAST_ACK:
//A device that has already received a close request and acknowledged it,
//has sent its own FIN and is waiting for an ACK to this request
tcpStateLastAck(socket, segment, length);
break;
//Process FIN_WAIT_1 state
case TCP_STATE_FIN_WAIT_1:
//A device in this state is waiting for an ACK for a FIN it has sent, or
//is waiting for a connection termination request from the other device
tcpStateFinWait1(socket, segment, buffer, offset, length);
break;
//Process FIN_WAIT_2 state
case TCP_STATE_FIN_WAIT_2:
//A device in this state has received an ACK for its request to terminate the
//connection and is now waiting for a matching FIN from the other device
tcpStateFinWait2(socket, segment, buffer, offset, length);
break;
//Process CLOSING state
case TCP_STATE_CLOSING:
//The device has received a FIN from the other device and sent an ACK for
//it, but not yet received an ACK for its own FIN message
tcpStateClosing(socket, segment, length);
break;
//Process TIME_WAIT state
case TCP_STATE_TIME_WAIT:
//The device has now received a FIN from the other device and acknowledged
//it, and sent its own FIN and received an ACK for it. We are done, except
//for waiting to ensure the ACK is received and prevent potential overlap
//with new connections
tcpStateTimeWait(socket, segment, length);
break;
//Invalid state...
default:
//Back to the CLOSED state
tcpChangeState(socket, TCP_STATE_CLOSED);
//Silently discard incoming packet
break;
}
}
error_t ipv4SendPacket(NetInterface *interface, Ipv4PseudoHeader *pseudoHeader,
uint16_t fragId, uint16_t fragOffset, NetBuffer *buffer, size_t offset, uint8_t ttl)
{
error_t error;
size_t length;
Ipv4Header *packet;
//Is there enough space for the IPv4 header?
if(offset < sizeof(Ipv4Header))
return ERROR_INVALID_PARAMETER;
//Make room for the header
offset -= sizeof(Ipv4Header);
//Calculate the size of the entire packet, including header and data
length = netBufferGetLength(buffer) - offset;
//Point to the IPv4 header
packet = netBufferAt(buffer, offset);
//Format IPv4 header
packet->version = IPV4_VERSION;
packet->headerLength = 5;
packet->typeOfService = 0;
packet->totalLength = htons(length);
packet->identification = htons(fragId);
packet->fragmentOffset = htons(fragOffset);
packet->timeToLive = ttl;
packet->protocol = pseudoHeader->protocol;
packet->headerChecksum = 0;
packet->srcAddr = pseudoHeader->srcAddr;
packet->destAddr = pseudoHeader->destAddr;
//Calculate IP header checksum
packet->headerChecksum = ipCalcChecksumEx(buffer, offset, packet->headerLength * 4);
//Ensure the source address is valid
error = ipv4CheckSourceAddr(interface, pseudoHeader->srcAddr);
//Invalid source address?
if(error) return error;
//Destination address is the unspecified address?
if(pseudoHeader->destAddr == IPV4_UNSPECIFIED_ADDR)
{
//Destination address is not acceptable
return ERROR_INVALID_ADDRESS;
}
//Destination address is the loopback address?
else if(pseudoHeader->destAddr == IPV4_LOOPBACK_ADDR)
{
//Not yet implemented...
return ERROR_NOT_IMPLEMENTED;
}
#if (ETH_SUPPORT == ENABLED)
//Ethernet interface?
if(interface->nicDriver->type == NIC_TYPE_ETHERNET)
{
Ipv4Addr destIpAddr;
MacAddr destMacAddr;
//Destination address is a broadcast address?
if(ipv4IsBroadcastAddr(interface, pseudoHeader->destAddr))
{
//Destination IPv4 address
destIpAddr = pseudoHeader->destAddr;
//Make use of the broadcast MAC address
destMacAddr = MAC_BROADCAST_ADDR;
//No error to report
error = NO_ERROR;
}
//Destination address is a multicast address?
else if(ipv4IsMulticastAddr(pseudoHeader->destAddr))
{
//Destination IPv4 address
destIpAddr = pseudoHeader->destAddr;
//Map IPv4 multicast address to MAC-layer multicast address
error = ipv4MapMulticastAddrToMac(pseudoHeader->destAddr, &destMacAddr);
}
//Destination host is in the local subnet?
else if(ipv4IsInLocalSubnet(interface, pseudoHeader->destAddr))
{
//Destination IPv4 address
destIpAddr = pseudoHeader->destAddr;
//Resolve host address before sending the packet
error = arpResolve(interface, pseudoHeader->destAddr, &destMacAddr);
}
//Destination host is outside the local subnet?
else
{
//Make sure the default gateway is properly set
if(interface->ipv4Config.defaultGateway != IPV4_UNSPECIFIED_ADDR)
{
//Use the default gateway to forward the packet
destIpAddr = interface->ipv4Config.defaultGateway;
//Perform address resolution
error = arpResolve(interface, interface->ipv4Config.defaultGateway, &destMacAddr);
}
else
{
//There is no route to the outside world...
error = ERROR_NO_ROUTE;
}
}
//Successful address resolution?
if(!error)
{
//Debug message
TRACE_INFO("Sending IPv4 packet (%" PRIuSIZE " bytes)...\r\n", length);
//Dump IP header contents for debugging purpose
ipv4DumpHeader(packet);
//Send Ethernet frame
error = ethSendFrame(interface, &destMacAddr, buffer, offset, ETH_TYPE_IPV4);
}
//Address resolution is in progress?
else if(error == ERROR_IN_PROGRESS)
{
//Debug message
TRACE_INFO("Enqueuing IPv4 packet (%" PRIuSIZE " bytes)...\r\n", length);
//Dump IP header contents for debugging purpose
ipv4DumpHeader(packet);
//Enqueue packets waiting for address resolution
error = arpEnqueuePacket(interface, destIpAddr, buffer, offset);
}
//Address resolution failed?
else
{
//Debug message
TRACE_WARNING("Cannot map IPv4 address to Ethernet address!\r\n");
}
}
else
#endif
#if (PPP_SUPPORT == ENABLED)
//PPP interface?
if(interface->nicDriver->type == NIC_TYPE_PPP)
{
//Debug message
TRACE_INFO("Sending IPv4 packet (%" PRIuSIZE " bytes)...\r\n", length);
//Dump IP header contents for debugging purpose
ipv4DumpHeader(packet);
//Send PPP frame
error = pppSendFrame(interface, buffer, offset, PPP_PROTOCOL_IP);
}
else
#endif
//Unknown interface type?
{
//Report an error
error = ERROR_INVALID_INTERFACE;
}
//Return status code
return error;
}
void ipv4ProcessDatagram(NetInterface *interface, const NetBuffer *buffer)
{
error_t error;
size_t offset;
size_t length;
Ipv4Header *header;
IpPseudoHeader pseudoHeader;
//Retrieve the length of the IPv4 datagram
length = netBufferGetLength(buffer);
//Point to the IPv4 header
header = netBufferAt(buffer, 0);
//Sanity check
if(!header) return;
//Debug message
TRACE_INFO("IPv4 datagram received (%" PRIuSIZE " bytes)...\r\n", length);
//Dump IP header contents for debugging purpose
ipv4DumpHeader(header);
//Get the offset to the payload
offset = header->headerLength * 4;
//Compute the length of the payload
length -= header->headerLength * 4;
//Form the IPv4 pseudo header
pseudoHeader.length = sizeof(Ipv4PseudoHeader);
pseudoHeader.ipv4Data.srcAddr = header->srcAddr;
pseudoHeader.ipv4Data.destAddr = header->destAddr;
pseudoHeader.ipv4Data.reserved = 0;
pseudoHeader.ipv4Data.protocol = header->protocol;
pseudoHeader.ipv4Data.length = htons(length);
#if defined(IPV4_DATAGRAM_FORWARD_HOOK)
IPV4_DATAGRAM_FORWARD_HOOK(interface, &pseudoHeader, buffer, offset);
#endif
//Check the protocol field
switch(header->protocol)
{
//ICMP protocol?
case IPV4_PROTOCOL_ICMP:
//Process incoming ICMP message
icmpProcessMessage(interface, header->srcAddr, buffer, offset);
#if (RAW_SOCKET_SUPPORT == ENABLED)
//Allow raw sockets to process ICMP messages
rawSocketProcessIpPacket(interface, &pseudoHeader, buffer, offset);
#endif
//No error to report
error = NO_ERROR;
//Continue processing
break;
#if (IGMP_SUPPORT == ENABLED)
//IGMP protocol?
case IPV4_PROTOCOL_IGMP:
//Process incoming IGMP message
igmpProcessMessage(interface, buffer, offset);
#if (RAW_SOCKET_SUPPORT == ENABLED)
//Allow raw sockets to process IGMP messages
rawSocketProcessIpPacket(interface, &pseudoHeader, buffer, offset);
#endif
//No error to report
error = NO_ERROR;
//Continue processing
break;
#endif
#if (TCP_SUPPORT == ENABLED)
//TCP protocol?
case IPV4_PROTOCOL_TCP:
//Process incoming TCP segment
tcpProcessSegment(interface, &pseudoHeader, buffer, offset);
//No error to report
error = NO_ERROR;
//Continue processing
break;
#endif
#if (UDP_SUPPORT == ENABLED)
//UDP protocol?
case IPV4_PROTOCOL_UDP:
//Process incoming UDP datagram
error = udpProcessDatagram(interface, &pseudoHeader, buffer, offset);
//Continue processing
break;
#endif
//Unknown protocol?
default:
#if (RAW_SOCKET_SUPPORT == ENABLED)
//Allow raw sockets to process IPv4 packets
error = rawSocketProcessIpPacket(interface, &pseudoHeader, buffer, offset);
#else
//Report an error
error = ERROR_PROTOCOL_UNREACHABLE;
#endif
//Continue processing
break;
}
//Unreachable protocol?
if(error == ERROR_PROTOCOL_UNREACHABLE)
{
//Send a Destination Unreachable message
icmpSendErrorMessage(interface, ICMP_TYPE_DEST_UNREACHABLE,
ICMP_CODE_PROTOCOL_UNREACHABLE, 0, buffer);
}
//Unreachable port?
else if(error == ERROR_PORT_UNREACHABLE)
{
//Send a Destination Unreachable message
icmpSendErrorMessage(interface, ICMP_TYPE_DEST_UNREACHABLE,
ICMP_CODE_PORT_UNREACHABLE, 0, buffer);
}
}
error_t rawSocketProcessIpPacket(NetInterface *interface,
IpPseudoHeader *pseudoHeader, const NetBuffer *buffer, size_t offset)
{
uint_t i;
size_t length;
Socket *socket;
SocketQueueItem *queueItem;
NetBuffer *p;
//Retrieve the length of the raw IP packet
length = netBufferGetLength(buffer) - offset;
//Enter critical section
osAcquireMutex(&socketMutex);
//Loop through opened sockets
for(i = 0; i < SOCKET_MAX_COUNT; i++)
{
//Point to the current socket
socket = socketTable + i;
//Raw socket found?
if(socket->type != SOCKET_TYPE_RAW_IP)
continue;
//Check whether the socket is bound to a particular interface
if(socket->interface && socket->interface != interface)
continue;
#if (IPV4_SUPPORT == ENABLED)
//An IPv4 packet was received?
if(pseudoHeader->length == sizeof(Ipv4PseudoHeader))
{
//Check protocol field
if(socket->protocol != pseudoHeader->ipv4Data.protocol)
continue;
//Destination IP address filtering
if(socket->localIpAddr.length)
{
//An IPv4 address is expected
if(socket->localIpAddr.length != sizeof(Ipv4Addr))
continue;
//Filter out non-matching addresses
if(socket->localIpAddr.ipv4Addr != pseudoHeader->ipv4Data.destAddr)
continue;
}
//Source IP address filtering
if(socket->remoteIpAddr.length)
{
//An IPv4 address is expected
if(socket->remoteIpAddr.length != sizeof(Ipv4Addr))
continue;
//Filter out non-matching addresses
if(socket->remoteIpAddr.ipv4Addr != pseudoHeader->ipv4Data.srcAddr)
continue;
}
}
else
#endif
#if (IPV6_SUPPORT == ENABLED)
//An IPv6 packet was received?
if(pseudoHeader->length == sizeof(Ipv6PseudoHeader))
{
//Check protocol field
if(socket->protocol != pseudoHeader->ipv6Data.nextHeader)
continue;
//Destination IP address filtering
if(socket->localIpAddr.length)
{
//An IPv6 address is expected
if(socket->localIpAddr.length != sizeof(Ipv6Addr))
continue;
//Filter out non-matching addresses
if(!ipv6CompAddr(&socket->localIpAddr.ipv6Addr, &pseudoHeader->ipv6Data.destAddr))
continue;
}
//Source IP address filtering
if(socket->remoteIpAddr.length)
{
//An IPv6 address is expected
if(socket->remoteIpAddr.length != sizeof(Ipv6Addr))
continue;
//Filter out non-matching addresses
if(!ipv6CompAddr(&socket->remoteIpAddr.ipv6Addr, &pseudoHeader->ipv6Data.srcAddr))
continue;
}
}
else
#endif
//An invalid packet was received?
{
//This should never occur...
continue;
}
//The current socket meets all the criteria
break;
}
//Drop incoming packet if no matching socket was found
if(i >= SOCKET_MAX_COUNT)
{
//Leave critical section
osReleaseMutex(&socketMutex);
//Unreachable protocol...
return ERROR_PROTOCOL_UNREACHABLE;
}
//Empty receive queue?
if(!socket->receiveQueue)
{
//Allocate a memory buffer to hold the data and the associated descriptor
p = netBufferAlloc(sizeof(SocketQueueItem) + length);
//Successful memory allocation?
if(p != NULL)
{
//Point to the newly created item
queueItem = netBufferAt(p, 0);
queueItem->buffer = p;
//Add the newly created item to the queue
socket->receiveQueue = queueItem;
}
else
{
//Memory allocation failed
queueItem = NULL;
}
}
else
{
//Point to the very first item
queueItem = socket->receiveQueue;
//Reach the last item in the receive queue
for(i = 1; queueItem->next; i++)
queueItem = queueItem->next;
//Make sure the receive queue is not full
if(i >= RAW_SOCKET_RX_QUEUE_SIZE)
{
//Leave critical section
osReleaseMutex(&socketMutex);
//Notify the calling function that the queue is full
return ERROR_RECEIVE_QUEUE_FULL;
}
//Allocate a memory buffer to hold the data and the associated descriptor
p = netBufferAlloc(sizeof(SocketQueueItem) + length);
//Successful memory allocation?
if(p != NULL)
{
//Add the newly created item to the queue
queueItem->next = netBufferAt(p, 0);
//Point to the newly created item
queueItem = queueItem->next;
queueItem->buffer = p;
}
else
{
//Memory allocation failed
queueItem = NULL;
}
}
//Failed to allocate memory?
if(!queueItem)
{
//Leave critical section
osReleaseMutex(&socketMutex);
//Return error code
return ERROR_OUT_OF_MEMORY;
}
//Initialize next field
queueItem->next = NULL;
//Port number is unused
queueItem->srcPort = 0;
#if (IPV4_SUPPORT == ENABLED)
//IPv4 remote address?
if(pseudoHeader->length == sizeof(Ipv4PseudoHeader))
{
//Save the source IPv4 address
queueItem->srcIpAddr.length = sizeof(Ipv4Addr);
queueItem->srcIpAddr.ipv4Addr = pseudoHeader->ipv4Data.srcAddr;
//Save the destination IPv4 address
queueItem->destIpAddr.length = sizeof(Ipv4Addr);
queueItem->destIpAddr.ipv4Addr = pseudoHeader->ipv4Data.destAddr;
}
#endif
#if (IPV6_SUPPORT == ENABLED)
//IPv6 remote address?
if(pseudoHeader->length == sizeof(Ipv6PseudoHeader))
{
//Save the source IPv6 address
queueItem->srcIpAddr.length = sizeof(Ipv6Addr);
queueItem->srcIpAddr.ipv6Addr = pseudoHeader->ipv6Data.srcAddr;
//Save the destination IPv6 address
queueItem->destIpAddr.length = sizeof(Ipv6Addr);
queueItem->destIpAddr.ipv6Addr = pseudoHeader->ipv6Data.destAddr;
}
#endif
//Offset to the raw IP packet
queueItem->offset = sizeof(SocketQueueItem);
//Copy the raw data
netBufferCopy(queueItem->buffer, queueItem->offset, buffer, offset, length);
//Notify user that data is available
rawSocketUpdateEvents(socket);
//Leave critical section
osReleaseMutex(&socketMutex);
//Successful processing
return NO_ERROR;
}
error_t mdnsSendResponse(NetInterface *interface, const IpPseudoHeader *pseudoHeader,
const UdpHeader *udpHeader, NetBuffer *buffer, size_t offset, size_t length)
{
uint16_t destPort;
IpAddr destIpAddr;
DnsHeader *response;
#if (IPV4_SUPPORT == ENABLED)
//Check whether the mDNS query was received from an IPv4 peer
if(pseudoHeader->length == sizeof(Ipv4PseudoHeader))
{
//If the source UDP port in a received Multicast DNS query is not port 5353,
//this indicates that the querier originating the query is a simple resolver
if(udpHeader->srcPort != HTONS(MDNS_PORT))
{
//the mDNS responder must send a UDP response directly back to the querier,
//via unicast, to the query packet's source IP address and port
destIpAddr.length = sizeof(Ipv4Addr);
destIpAddr.ipv4Addr = pseudoHeader->ipv4Data.srcAddr;
}
else
{
//Use mDNS IPv4 multicast address
destIpAddr.length = sizeof(Ipv4Addr);
destIpAddr.ipv4Addr = MDNS_IPV4_MULTICAST_ADDR;
}
}
#endif
#if (IPV6_SUPPORT == ENABLED)
//Check whether the mDNS query was received from an IPv6 peer
if(pseudoHeader->length == sizeof(Ipv6PseudoHeader))
{
//If the source UDP port in a received Multicast DNS query is not port 5353,
//this indicates that the querier originating the query is a simple resolver
if(udpHeader->srcPort != HTONS(MDNS_PORT))
{
//the mDNS responder must send a UDP response directly back to the querier,
//via unicast, to the query packet's source IP address and port
destIpAddr.length = sizeof(Ipv6Addr);
destIpAddr.ipv6Addr = pseudoHeader->ipv6Data.srcAddr;
}
else
{
//Use mDNS IPv6 multicast address
destIpAddr.length = sizeof(Ipv6Addr);
destIpAddr.ipv6Addr = MDNS_IPV6_MULTICAST_ADDR;
}
}
#endif
//Destination port
destPort = ntohs(udpHeader->srcPort);
//Point to the mDNS response header
response = netBufferAt(buffer, offset);
//Convert 16-bit value to network byte order
response->ancount = htons(response->ancount);
//Adjust the length of the multi-part buffer
netBufferSetLength(buffer, offset + length);
//Debug message
TRACE_INFO("Sending mDNS message (%" PRIuSIZE " bytes)...\r\n", length);
//Dump message
dnsDumpMessage(response, length);
//All multicast DNS responses should be sent with an IP TTL set to 255
return udpSendDatagramEx(interface, MDNS_PORT, &destIpAddr,
destPort, buffer, offset, MDNS_DEFAULT_IP_TTL);
}
Ipv4HoleDesc *ipv4FindHole(Ipv4FragDesc *frag, uint16_t offset)
{
//Return a pointer to the hole descriptor
return netBufferAt((NetBuffer *) &frag->buffer, frag->headerLength + offset);
}
void rawSocketProcessEthPacket(NetInterface *interface,
EthHeader *ethFrame, size_t length)
{
uint_t i;
Socket *socket;
SocketQueueItem *queueItem;
NetBuffer *p;
//Enter critical section
osAcquireMutex(&socketMutex);
//Loop through opened sockets
for(i = 0; i < SOCKET_MAX_COUNT; i++)
{
//Point to the current socket
socket = socketTable + i;
//Raw socket found?
if(socket->type != SOCKET_TYPE_RAW_ETH)
continue;
//Check whether the socket is bound to a particular interface
if(socket->interface && socket->interface != interface)
continue;
//Check protocol field
if(socket->protocol != SOCKET_ETH_PROTO_ALL && socket->protocol != ntohs(ethFrame->type))
continue;
//The current socket meets all the criteria
break;
}
//Drop incoming packet if no matching socket was found
if(i >= SOCKET_MAX_COUNT)
{
//Leave critical section
osReleaseMutex(&socketMutex);
//Return immediately
return;
}
//Empty receive queue?
if(!socket->receiveQueue)
{
//Allocate a memory buffer to hold the data and the associated descriptor
p = netBufferAlloc(sizeof(SocketQueueItem) + length);
//Successful memory allocation?
if(p != NULL)
{
//Point to the newly created item
queueItem = netBufferAt(p, 0);
queueItem->buffer = p;
//Add the newly created item to the queue
socket->receiveQueue = queueItem;
}
else
{
//Memory allocation failed
queueItem = NULL;
}
}
else
{
//Point to the very first item
queueItem = socket->receiveQueue;
//Reach the last item in the receive queue
for(i = 1; queueItem->next; i++)
queueItem = queueItem->next;
//Make sure the receive queue is not full
if(i >= RAW_SOCKET_RX_QUEUE_SIZE)
{
//Leave critical section
osReleaseMutex(&socketMutex);
//Return immediately
return;
}
//Allocate a memory buffer to hold the data and the associated descriptor
p = netBufferAlloc(sizeof(SocketQueueItem) + length);
//Successful memory allocation?
if(p != NULL)
{
//Add the newly created item to the queue
queueItem->next = netBufferAt(p, 0);
//Point to the newly created item
queueItem = queueItem->next;
queueItem->buffer = p;
}
else
{
//Memory allocation failed
queueItem = NULL;
}
}
//Failed to allocate memory?
if(!queueItem)
{
//Leave critical section
osReleaseMutex(&socketMutex);
//Return immediately
return;
}
//Initialize next field
queueItem->next = NULL;
//Other fields are meaningless
queueItem->srcPort = 0;
queueItem->srcIpAddr = IP_ADDR_ANY;
queueItem->destIpAddr = IP_ADDR_ANY;
//Offset to the raw datagram
queueItem->offset = sizeof(SocketQueueItem);
//Copy the raw data
netBufferWrite(queueItem->buffer, queueItem->offset, ethFrame, length);
//Notify user that data is available
rawSocketUpdateEvents(socket);
//Leave critical section
osReleaseMutex(&socketMutex);
}
error_t pppSendConfigureAckNak(PppContext *context,
const PppConfigurePacket *configureReqPacket, PppProtocol protocol, PppCode code)
{
error_t error;
size_t length;
size_t offset;
NetBuffer *buffer;
PppConfigurePacket *configureAckNakPacket;
PppOption *option;
//Initialize status code
error = NO_ERROR;
//Retrieve the length of the Configure-Request packet
length = ntohs(configureReqPacket->length);
//Allocate a buffer memory to hold the Configure-Ack, Nak or Reject packet
buffer = pppAllocBuffer(length, &offset);
//Failed to allocate memory?
if(!buffer) return ERROR_OUT_OF_MEMORY;
//Point to the beginning of the packet
configureAckNakPacket = netBufferAt(buffer, offset);
//Format packet header
configureAckNakPacket->code = code;
configureAckNakPacket->identifier = configureReqPacket->identifier;
configureAckNakPacket->length = sizeof(PppConfigurePacket);
//Retrieve the length of the option list
length -= sizeof(PppConfigurePacket);
//Point to the first option
option = (PppOption *) configureReqPacket->options;
//Parse configuration options
while(length > 0)
{
//LCP protocol?
if(protocol == PPP_PROTOCOL_LCP)
{
//Parse LCP option
lcpParseOption(context, option, length, configureAckNakPacket);
}
#if (IPV4_SUPPORT)
//IPCP protocol?
else if(protocol == PPP_PROTOCOL_IPCP)
{
//Parse IPCP option
ipcpParseOption(context, option, length, configureAckNakPacket);
}
#endif
//Remaining bytes to process
length -= option->length;
//Jump to the next option
option = (PppOption *) ((uint8_t *) option + option->length);
}
//Adjust the length of the multi-part buffer
netBufferSetLength(buffer, offset + configureAckNakPacket->length);
//Convert length field to network byte order
configureAckNakPacket->length = htons(configureAckNakPacket->length);
//Debug message
if(code == PPP_CODE_CONFIGURE_ACK)
{
TRACE_INFO("Sending Configure-Ack packet (%" PRIuSIZE " bytes)...\r\n",
ntohs(configureAckNakPacket->length));
}
else if(code == PPP_CODE_CONFIGURE_NAK)
{
TRACE_INFO("Sending Configure-Nak packet (%" PRIuSIZE " bytes)...\r\n",
ntohs(configureAckNakPacket->length));
}
else if(code == PPP_CODE_CONFIGURE_REJ)
{
TRACE_INFO("Sending Configure-Reject packet (%" PRIuSIZE " bytes)...\r\n",
ntohs(configureAckNakPacket->length));
}
//Dump packet contents for debugging purpose
pppDumpPacket((PppPacket *) configureAckNakPacket,
ntohs(configureAckNakPacket->length), protocol);
//Send PPP frame
error = pppSendFrame(context->interface, buffer, offset, protocol);
//Free previously allocated memory block
netBufferFree(buffer);
//Return status code
return error;
}
error_t nbnsSendQuery(DnsCacheEntry *entry)
{
error_t error;
size_t length;
size_t offset;
NetBuffer *buffer;
NbnsHeader *message;
DnsQuestion *dnsQuestion;
IpAddr destIpAddr;
//Allocate a memory buffer to hold the NBNS query message
buffer = udpAllocBuffer(DNS_MESSAGE_MAX_SIZE, &offset);
//Failed to allocate buffer?
if(!buffer) return ERROR_OUT_OF_MEMORY;
//Point to the NBNS header
message = netBufferAt(buffer, offset);
//Format NBNS query message
message->id = htons(entry->id);
message->qr = 0;
message->opcode = DNS_OPCODE_QUERY;
message->aa = 0;
message->tc = 0;
message->rd = 0;
message->ra = 0;
message->z = 0;
message->b = 1;
message->rcode = DNS_RCODE_NO_ERROR;
//The NBNS query contains one question
message->qdcount = HTONS(1);
message->ancount = 0;
message->nscount = 0;
message->arcount = 0;
//Length of the NBNS query message
length = sizeof(DnsHeader);
//Encode the NetBIOS name
length += nbnsEncodeName(entry->name, message->questions);
//Point to the corresponding question structure
dnsQuestion = DNS_GET_QUESTION(message, length);
//Fill in question structure
dnsQuestion->qtype = HTONS(DNS_RR_TYPE_NB);
dnsQuestion->qclass = HTONS(DNS_RR_CLASS_IN);
//Update the length of the NBNS query message
length += sizeof(DnsQuestion);
//Adjust the length of the multi-part buffer
netBufferSetLength(buffer, offset + length);
//Debug message
TRACE_INFO("Sending NBNS message (%" PRIuSIZE " bytes)...\r\n", length);
//Dump message
dnsDumpMessage((DnsHeader *) message, length);
//The destination address is the broadcast address
destIpAddr.length = sizeof(Ipv4Addr);
ipv4GetBroadcastAddr(entry->interface, &destIpAddr.ipv4Addr);
//A request packet is always sent to the well known port 137
error = udpSendDatagramEx(entry->interface, NBNS_PORT,
&destIpAddr, NBNS_PORT, buffer, offset, IPV4_DEFAULT_TTL);
//Free previously allocated memory
netBufferFree(buffer);
//Return status code
return error;
}
error_t dnsSendQuery(DnsCacheEntry *entry)
{
error_t error;
size_t length;
size_t offset;
NetBuffer *buffer;
DnsHeader *message;
DnsQuestion *dnsQuestion;
IpAddr destIpAddr;
#if (IPV4_SUPPORT == ENABLED)
//An IPv4 address is expected?
if(entry->type == HOST_TYPE_IPV4)
{
//Select the relevant DNS server
destIpAddr.length = sizeof(Ipv4Addr);
ipv4GetDnsServer(entry->interface, entry->dnsServerNum, &destIpAddr.ipv4Addr);
//Make sure the IP address is valid
if(destIpAddr.ipv4Addr == IPV4_UNSPECIFIED_ADDR)
return ERROR_NO_DNS_SERVER;
}
else
#endif
#if (IPV6_SUPPORT == ENABLED)
//An IPv6 address is expected?
if(entry->type == HOST_TYPE_IPV6)
{
//Select the relevant DNS server
destIpAddr.length = sizeof(Ipv6Addr);
ipv6GetDnsServer(entry->interface, entry->dnsServerNum, &destIpAddr.ipv6Addr);
//Make sure the IP address is valid
if(ipv6CompAddr(&destIpAddr.ipv6Addr, &IPV6_UNSPECIFIED_ADDR))
return ERROR_NO_DNS_SERVER;
}
else
#endif
//Invalid host type?
{
//Report an error
return ERROR_INVALID_PARAMETER;
}
//Allocate a memory buffer to hold the DNS query message
buffer = udpAllocBuffer(DNS_MESSAGE_MAX_SIZE, &offset);
//Failed to allocate buffer?
if(!buffer) return ERROR_OUT_OF_MEMORY;
//Point to the DNS header
message = netBufferAt(buffer, offset);
//Format DNS query message
message->id = htons(entry->id);
message->qr = 0;
message->opcode = DNS_OPCODE_QUERY;
message->aa = 0;
message->tc = 0;
message->rd = 1;
message->ra = 0;
message->z = 0;
message->rcode = DNS_RCODE_NO_ERROR;
//The DNS query contains one question
message->qdcount = HTONS(1);
message->ancount = 0;
message->nscount = 0;
message->arcount = 0;
//Length of the DNS query message
length = sizeof(DnsHeader);
//Encode the host name using the DNS name notation
length += dnsEncodeName(entry->name, message->questions);
//Point to the corresponding question structure
dnsQuestion = DNS_GET_QUESTION(message, length);
#if (IPV4_SUPPORT == ENABLED)
//An IPv4 address is expected?
if(entry->type == HOST_TYPE_IPV4)
{
//Fill in question structure
dnsQuestion->qtype = HTONS(DNS_RR_TYPE_A);
dnsQuestion->qclass = HTONS(DNS_RR_CLASS_IN);
}
#endif
#if (IPV6_SUPPORT == ENABLED)
//An IPv6 address is expected?
if(entry->type == HOST_TYPE_IPV6)
{
//Fill in question structure
dnsQuestion->qtype = HTONS(DNS_RR_TYPE_AAAA);
dnsQuestion->qclass = HTONS(DNS_RR_CLASS_IN);
}
#endif
//Update the length of the DNS query message
length += sizeof(DnsQuestion);
//Adjust the length of the multi-part buffer
netBufferSetLength(buffer, offset + length);
//Debug message
TRACE_INFO("Sending DNS message (%" PRIuSIZE " bytes)...\r\n", length);
//Dump message
dnsDumpMessage(message, length);
//Send DNS query message
error = udpSendDatagramEx(entry->interface, entry->port,
&destIpAddr, DNS_PORT, buffer, offset, 0);
//Free previously allocated memory
netBufferFree(buffer);
//Return status code
return error;
}
error_t udpSendDatagramEx(NetInterface *interface, uint16_t srcPort, const IpAddr *destIpAddr,
uint16_t destPort, NetBuffer *buffer, size_t offset, uint8_t ttl)
{
error_t error;
size_t length;
UdpHeader *header;
IpPseudoHeader pseudoHeader;
//Make room for the UDP header
offset -= sizeof(UdpHeader);
//Retrieve the length of the datagram
length = netBufferGetLength(buffer) - offset;
//Point to the UDP header
header = netBufferAt(buffer, offset);
//Sanity check
if(!header) return ERROR_FAILURE;
//Format UDP header
header->srcPort = htons(srcPort);
header->destPort = htons(destPort);
header->length = htons(length);
header->checksum = 0;
#if (IPV4_SUPPORT == ENABLED)
//Destination address is an IPv4 address?
if(destIpAddr->length == sizeof(Ipv4Addr))
{
Ipv4Addr srcIpAddr;
//Select the source IPv4 address and the relevant network interface
//to use when sending data to the specified destination host
error = ipv4SelectSourceAddr(&interface, destIpAddr->ipv4Addr, &srcIpAddr);
//Any error to report?
if(error) return error;
//Format IPv4 pseudo header
pseudoHeader.length = sizeof(Ipv4PseudoHeader);
pseudoHeader.ipv4Data.srcAddr = srcIpAddr;
pseudoHeader.ipv4Data.destAddr = destIpAddr->ipv4Addr;
pseudoHeader.ipv4Data.reserved = 0;
pseudoHeader.ipv4Data.protocol = IPV4_PROTOCOL_UDP;
pseudoHeader.ipv4Data.length = htons(length);
//Calculate UDP header checksum
header->checksum = ipCalcUpperLayerChecksumEx(&pseudoHeader.ipv4Data,
sizeof(Ipv4PseudoHeader), buffer, offset, length);
}
else
#endif
#if (IPV6_SUPPORT == ENABLED)
//Destination address is an IPv6 address?
if(destIpAddr->length == sizeof(Ipv6Addr))
{
//Select the source IPv6 address and the relevant network interface
//to use when sending data to the specified destination host
error = ipv6SelectSourceAddr(&interface,
&destIpAddr->ipv6Addr, &pseudoHeader.ipv6Data.srcAddr);
//Any error to report?
if(error) return error;
//Format IPv6 pseudo header
pseudoHeader.length = sizeof(Ipv6PseudoHeader);
pseudoHeader.ipv6Data.destAddr = destIpAddr->ipv6Addr;
pseudoHeader.ipv6Data.length = htonl(length);
pseudoHeader.ipv6Data.reserved = 0;
pseudoHeader.ipv6Data.nextHeader = IPV6_UDP_HEADER;
//Calculate UDP header checksum
header->checksum = ipCalcUpperLayerChecksumEx(&pseudoHeader.ipv6Data,
sizeof(Ipv6PseudoHeader), buffer, offset, length);
}
else
#endif
//Invalid destination address?
{
//An internal error has occurred
return ERROR_FAILURE;
}
//Debug message
TRACE_INFO("Sending UDP datagram (%" PRIuSIZE " bytes)\r\n", length);
//Dump UDP header contents for debugging purpose
udpDumpHeader(header);
//Send UDP datagram
return ipSendDatagram(interface, &pseudoHeader, buffer, offset, ttl);
}
void ipv4ReassembleDatagram(NetInterface *interface,
const Ipv4Header *packet, size_t length)
{
error_t error;
uint16_t offset;
uint16_t dataFirst;
uint16_t dataLast;
Ipv4FragDesc *frag;
Ipv4HoleDesc *hole;
Ipv4HoleDesc *prevHole;
//Get the length of the payload
length -= packet->headerLength * 4;
//Convert the fragment offset from network byte order
offset = ntohs(packet->fragmentOffset);
//Every fragment except the last must contain a multiple of 8 bytes of data
if((offset & IPV4_FLAG_MF) && (length % 8))
{
//Drop incoming packet
return;
}
//Calculate the index of the first byte
dataFirst = (offset & IPV4_OFFSET_MASK) * 8;
//Calculate the index immediately following the last byte
dataLast = dataFirst + length;
//Search for a matching IP datagram being reassembled
frag = ipv4SearchFragQueue(interface, packet);
//No matching entry in the reassembly queue?
if(!frag) return;
//The very first fragment requires special handling
if(!(offset & IPV4_OFFSET_MASK))
{
//Calculate the length of the IP header including options
frag->headerLength = packet->headerLength * 4;
//Enforce the size of the reconstructed datagram
if((frag->headerLength + frag->dataLength) > IPV4_MAX_FRAG_DATAGRAM_SIZE)
{
//Drop any allocated resources
netBufferSetLength((NetBuffer *) &frag->buffer, 0);
//Exit immediately
return;
}
//Make sure the IP header entirely fits in the first chunk
if(frag->headerLength > frag->buffer.chunk[0].size)
{
//Drop the reconstructed datagram
netBufferSetLength((NetBuffer *) &frag->buffer, 0);
//Exit immediately
return;
}
//Fix the length of the first chunk
frag->buffer.chunk[0].length = frag->headerLength;
//Always take the IP header from the first fragment
netBufferWrite((NetBuffer *) &frag->buffer, 0, packet, frag->headerLength);
}
//It may be necessary to increase the size of the buffer...
if(dataLast > frag->dataLength)
{
//Enforce the size of the reconstructed datagram
if((frag->headerLength + dataLast) > IPV4_MAX_FRAG_DATAGRAM_SIZE)
{
//Drop any allocated resources
netBufferSetLength((NetBuffer *) &frag->buffer, 0);
//Exit immediately
return;
}
//Adjust the size of the reconstructed datagram
error = netBufferSetLength((NetBuffer *) &frag->buffer,
frag->headerLength + dataLast + sizeof(Ipv4HoleDesc));
//Any error to report?
if(error)
{
//Drop the reconstructed datagram
netBufferSetLength((NetBuffer *) &frag->buffer, 0);
//Exit immediately
return;
}
//Actual length of the payload
frag->dataLength = dataLast;
}
//Select the first hole descriptor from the list
hole = ipv4FindHole(frag, frag->firstHole);
//Keep track of the previous hole in the list
prevHole = NULL;
//Iterate through the hole descriptors
while(hole != NULL)
{
//Save lower and upper boundaries for later use
uint16_t holeFirst = hole->first;
uint16_t holeLast = hole->last;
//Check whether the newly arrived fragment
//interacts with this hole in some way
if(dataFirst < holeLast && dataLast > holeFirst)
{
//The current descriptor is no longer valid. We will destroy
//it, and in the next two steps, we will determine whether
//or not it is necessary to create any new hole descriptors
if(prevHole != NULL)
prevHole->next = hole->next;
else
frag->firstHole = hole->next;
//Is there still a hole at the beginning of the segment?
if(dataFirst > holeFirst)
{
//Create a new entry that describes this hole
hole = ipv4FindHole(frag, holeFirst);
hole->first = holeFirst;
hole->last = dataFirst;
//Insert the newly created entry into the hole descriptor list
if(prevHole != NULL)
{
hole->next = prevHole->next;
prevHole->next = hole->first;
}
else
{
hole->next = frag->firstHole;
frag->firstHole = hole->first;
}
//Always keep track of the previous hole
prevHole = hole;
}
//Is there still a hole at the end of the segment?
if(dataLast < holeLast && (offset & IPV4_FLAG_MF))
{
//Create a new entry that describes this hole
hole = ipv4FindHole(frag, dataLast);
hole->first = dataLast;
hole->last = holeLast;
//Insert the newly created entry into the hole descriptor list
if(prevHole != NULL)
{
hole->next = prevHole->next;
prevHole->next = hole->first;
}
else
{
hole->next = frag->firstHole;
frag->firstHole = hole->first;
}
//Always keep track of the previous hole
prevHole = hole;
}
}
else
{
//The newly arrived fragment does not interact with the current hole
prevHole = hole;
}
//Select the next hole descriptor from the list
hole = ipv4FindHole(frag, prevHole ? prevHole->next : frag->firstHole);
}
//Copy data from the fragment to the reassembly buffer
netBufferWrite((NetBuffer *) &frag->buffer,
frag->headerLength + dataFirst, IPV4_DATA(packet), length);
//Dump hole descriptor list
ipv4DumpHoleList(frag);
//If the hole descriptor list is empty, the reassembly process is now complete
if(!ipv4FindHole(frag, frag->firstHole))
{
//Discard the extra hole descriptor that follows the reconstructed datagram
error = netBufferSetLength((NetBuffer *) &frag->buffer,
frag->headerLength + frag->dataLength);
//Check status code
if(!error)
{
//Point to the IP header
Ipv4Header *datagram = netBufferAt((NetBuffer *) &frag->buffer, 0);
//Fix IP header
datagram->totalLength = htons(frag->headerLength + frag->dataLength);
datagram->fragmentOffset = 0;
datagram->headerChecksum = 0;
//Recalculate IP header checksum
datagram->headerChecksum = ipCalcChecksum(datagram, frag->buffer.chunk[0].length);
//Pass the original IPv4 datagram to the higher protocol layer
ipv4ProcessDatagram(interface, (NetBuffer *) &frag->buffer);
}
//Release previously allocated memory
netBufferSetLength((NetBuffer *) &frag->buffer, 0);
}
}
