error_t ipv4FragmentDatagram(NetInterface *interface, Ipv4PseudoHeader *pseudoHeader,
uint16_t id, const ChunkedBuffer *payload, size_t payloadOffset, uint8_t timeToLive)
{
error_t error;
size_t offset;
size_t length;
size_t payloadLength;
size_t fragmentOffset;
ChunkedBuffer *fragment;
//Retrieve the length of the payload
payloadLength = chunkedBufferGetLength(payload) - payloadOffset;
//Allocate a memory buffer to hold IP fragments
fragment = ipAllocBuffer(0, &fragmentOffset);
//Failed to allocate memory?
if(!fragment)
return ERROR_OUT_OF_MEMORY;
//Split the payload into multiple IP fragments
for(offset = 0; offset < payloadLength; offset += length)
{
//Flush the contents of the fragment
error = chunkedBufferSetLength(fragment, fragmentOffset);
//Sanity check
if(error) break;
//Process the last fragment?
if((payloadLength - offset) <= IPV4_MAX_FRAG_SIZE)
{
//Size of the current fragment
length = payloadLength - offset;
//Copy fragment data
chunkedBufferConcat(fragment, payload, payloadOffset + offset, length);
//Do not set the MF flag for the last fragment
error = ipv4SendPacket(interface, pseudoHeader, id,
offset / 8, fragment, fragmentOffset, timeToLive);
}
else
{
//Size of the current fragment (must be a multiple of 8-byte blocks)
length = IPV4_MAX_FRAG_SIZE;
//Copy fragment data
chunkedBufferConcat(fragment, payload, payloadOffset + offset, length);
//Fragmented packets must have the MF flag set
error = ipv4SendPacket(interface, pseudoHeader, id,
IPV4_FLAG_MF | (offset / 8), fragment, fragmentOffset, timeToLive);
}
//Failed to send current IP packet?
if(error) break;
}
//Free previously allocated memory
chunkedBufferFree(fragment);
//Return status code
return error;
}
error_t icmpSendErrorMessage(NetInterface *interface, uint8_t type,
uint8_t code, uint8_t parameter, const ChunkedBuffer *ipPacket)
{
error_t error;
size_t offset;
size_t length;
Ipv4Header *ipHeader;
ChunkedBuffer *icmpMessage;
IcmpErrorMessage *icmpHeader;
Ipv4PseudoHeader pseudoHeader;
//Retrieve the length of the invoking IPv4 packet
length = chunkedBufferGetLength(ipPacket);
//Check the length of the IPv4 packet
if(length < sizeof(Ipv4Header))
return ERROR_INVALID_LENGTH;
//Point to the header of the invoking packet
ipHeader = chunkedBufferAt(ipPacket, 0);
//Sanity check
if(!ipHeader) return ERROR_FAILURE;
//Never respond to a packet destined to a broadcast or a multicast address
if(ipv4IsBroadcastAddr(interface, ipHeader->destAddr) ||
ipv4IsMulticastAddr(ipHeader->destAddr))
{
//Report an error
return ERROR_INVALID_ADDRESS;
}
//Length of the data that will be returned along with the ICMP header
length = MIN(length, ipHeader->headerLength * 4 + 8);
//Allocate a memory buffer to hold the ICMP message
icmpMessage = ipAllocBuffer(sizeof(IcmpErrorMessage), &offset);
//Failed to allocate memory?
if(!icmpMessage) return ERROR_OUT_OF_MEMORY;
//Point to the ICMP header
icmpHeader = chunkedBufferAt(icmpMessage, offset);
//Format ICMP message
icmpHeader->type = type;
icmpHeader->code = code;
icmpHeader->checksum = 0;
icmpHeader->parameter = parameter;
icmpHeader->unused = 0;
//Copy the IP header and the first 8 bytes of the original datagram data
error = chunkedBufferConcat(icmpMessage, ipPacket, 0, length);
//Any error to report?
if(error)
{
//Clean up side effects
chunkedBufferFree(icmpMessage);
//Exit immediately
return error;
}
//Get the length of the resulting message
length = chunkedBufferGetLength(icmpMessage) - offset;
//Message checksum calculation
icmpHeader->checksum = ipCalcChecksumEx(icmpMessage, offset, length);
//Format IPv4 pseudo header
pseudoHeader.srcAddr = ipHeader->destAddr;
pseudoHeader.destAddr = ipHeader->srcAddr;
pseudoHeader.reserved = 0;
pseudoHeader.protocol = IPV4_PROTOCOL_ICMP;
pseudoHeader.length = htons(length);
//Debug message
TRACE_INFO("Sending ICMP Error message (%" PRIuSIZE " bytes)...\r\n", length);
//Dump message contents for debugging purpose
icmpDumpErrorMessage(icmpHeader);
//Send ICMP Error message
error = ipv4SendDatagram(interface, &pseudoHeader,
icmpMessage, offset, IPV4_DEFAULT_TTL);
//Free previously allocated memory
chunkedBufferFree(icmpMessage);
//Return status code
return error;
}
void icmpProcessEchoRequest(NetInterface *interface,
Ipv4Addr srcIpAddr, const ChunkedBuffer *request, size_t requestOffset)
{
error_t error;
size_t requestLength;
size_t replyOffset;
size_t replyLength;
ChunkedBuffer *reply;
IcmpEchoMessage *requestHeader;
IcmpEchoMessage *replyHeader;
Ipv4PseudoHeader pseudoHeader;
//Retrieve the length of the Echo Request message
requestLength = chunkedBufferGetLength(request) - requestOffset;
//Ensure the packet length is correct
if(requestLength < sizeof(IcmpEchoMessage))
return;
//Point to the Echo Request header
requestHeader = chunkedBufferAt(request, requestOffset);
//Sanity check
if(!requestHeader) return;
//Debug message
TRACE_INFO("ICMP Echo Request message received (%" PRIuSIZE " bytes)...\r\n", requestLength);
//Dump message contents for debugging purpose
icmpDumpEchoMessage(requestHeader);
//Allocate memory to hold the Echo Reply message
reply = ipAllocBuffer(sizeof(IcmpEchoMessage), &replyOffset);
//Failed to allocate memory?
if(!reply) return;
//Point to the Echo Reply header
replyHeader = chunkedBufferAt(reply, replyOffset);
//Format Echo Reply header
replyHeader->type = ICMP_TYPE_ECHO_REPLY;
replyHeader->code = 0;
replyHeader->checksum = 0;
replyHeader->identifier = requestHeader->identifier;
replyHeader->sequenceNumber = requestHeader->sequenceNumber;
//Point to the first data byte
requestOffset += sizeof(IcmpEchoMessage);
requestLength -= sizeof(IcmpEchoMessage);
//Copy data
error = chunkedBufferConcat(reply, request, requestOffset, requestLength);
//Any error to report?
if(error)
{
//Clean up side effects
chunkedBufferFree(reply);
//Exit immediately
return;
}
//Get the length of the resulting message
replyLength = chunkedBufferGetLength(reply) - replyOffset;
//Calculate ICMP header checksum
replyHeader->checksum = ipCalcChecksumEx(reply, replyOffset, replyLength);
//Format IPv4 pseudo header
pseudoHeader.srcAddr = interface->ipv4Config.addr;
pseudoHeader.destAddr = srcIpAddr;
pseudoHeader.reserved = 0;
pseudoHeader.protocol = IPV4_PROTOCOL_ICMP;
pseudoHeader.length = htons(replyLength);
//Debug message
TRACE_INFO("Sending ICMP Echo Reply message (%" PRIuSIZE " bytes)...\r\n", replyLength);
//Dump message contents for debugging purpose
icmpDumpEchoMessage(replyHeader);
//Send Echo Reply message
ipv4SendDatagram(interface, &pseudoHeader, reply, replyOffset, IPV4_DEFAULT_TTL);
//Free previously allocated memory block
chunkedBufferFree(reply);
}
error_t icmpv6SendErrorMessage(NetInterface *interface, uint8_t type,
uint8_t code, uint32_t parameter, const ChunkedBuffer *ipPacket)
{
error_t error;
size_t offset;
size_t length;
Ipv6Header *ipHeader;
ChunkedBuffer *icmpMessage;
Icmpv6ErrorMessage *icmpHeader;
Ipv6PseudoHeader pseudoHeader;
//Retrieve the length of the invoking IPv6 packet
length = chunkedBufferGetLength(ipPacket);
//Check the length of the IPv6 packet
if(length < sizeof(Ipv6Header))
return ERROR_INVALID_LENGTH;
//Point to the header of the invoking packet
ipHeader = chunkedBufferAt(ipPacket, 0);
//Sanity check
if(!ipHeader) return ERROR_FAILURE;
//Never respond to a packet destined to an IPv6 multicast address
if(ipv6IsMulticastAddr(&ipHeader->destAddr))
return ERROR_INVALID_ADDRESS;
//Return as much of invoking IPv6 packet as possible without
//the ICMPv6 packet exceeding the minimum IPv6 MTU
length = MIN(length, IPV6_DEFAULT_MTU -
sizeof(Ipv6Header) - sizeof(Icmpv6ErrorMessage));
//Allocate a memory buffer to hold the ICMPv6 message
icmpMessage = ipAllocBuffer(sizeof(Icmpv6ErrorMessage), &offset);
//Failed to allocate memory?
if(!icmpMessage) return ERROR_OUT_OF_MEMORY;
//Point to the ICMPv6 header
icmpHeader = chunkedBufferAt(icmpMessage, offset);
//Format ICMPv6 Error message
icmpHeader->type = type;
icmpHeader->code = code;
icmpHeader->checksum = 0;
icmpHeader->parameter = htonl(parameter);
//Copy incoming IPv6 packet contents
error = chunkedBufferConcat(icmpMessage, ipPacket, 0, length);
//Any error to report?
if(error)
{
//Clean up side effects
chunkedBufferFree(icmpMessage);
//Exit immediately
return error;
}
//Get the length of the resulting message
length = chunkedBufferGetLength(icmpMessage) - offset;
//Format IPv6 pseudo header
pseudoHeader.srcAddr = ipHeader->destAddr;
pseudoHeader.destAddr = ipHeader->srcAddr;
pseudoHeader.length = htonl(length);
pseudoHeader.reserved = 0;
pseudoHeader.nextHeader = IPV6_ICMPV6_HEADER;
//Message checksum calculation
icmpHeader->checksum = ipCalcUpperLayerChecksumEx(&pseudoHeader,
sizeof(Ipv6PseudoHeader), icmpMessage, offset, length);
//Debug message
TRACE_INFO("Sending ICMPv6 Error message (%" PRIuSIZE " bytes)...\r\n", length);
//Dump message contents for debugging purpose
icmpv6DumpErrorMessage(icmpHeader);
//Send ICMPv6 Error message
error = ipv6SendDatagram(interface, &pseudoHeader,
icmpMessage, offset, IPV6_DEFAULT_HOP_LIMIT);
//Free previously allocated memory
chunkedBufferFree(icmpMessage);
//Return status code
return error;
}
error_t ipv6FragmentDatagram(NetInterface *interface, Ipv6PseudoHeader *pseudoHeader,
const ChunkedBuffer *payload, size_t payloadOffset, uint8_t hopLimit)
{
error_t error;
uint32_t id;
size_t offset;
size_t length;
size_t payloadLength;
size_t fragmentOffset;
ChunkedBuffer *fragment;
//Identification field is used to identify fragments of an original IP datagram
id = osAtomicInc32(&interface->ipv6Identification);
//Retrieve the length of the payload
payloadLength = chunkedBufferGetLength(payload) - payloadOffset;
//Allocate a memory buffer to hold IP fragments
fragment = ipAllocBuffer(0, &fragmentOffset);
//Failed to allocate memory?
if(!fragment)
return ERROR_OUT_OF_MEMORY;
//Split the payload into multiple IP fragments
for(offset = 0; offset < payloadLength; offset += length)
{
//Flush the contents of the fragment
error = chunkedBufferSetLength(fragment, fragmentOffset);
//Sanity check
if(error) break;
//Process the last fragment?
if((payloadLength - offset) <= IPV6_MAX_FRAG_SIZE)
{
//Size of the current fragment
length = payloadLength - offset;
//Copy fragment data
chunkedBufferConcat(fragment, payload, payloadOffset + offset, length);
//Do not set the MF flag for the last fragment
error = ipv6SendPacket(interface, pseudoHeader, id,
offset, fragment, fragmentOffset, hopLimit);
}
else
{
//Size of the current fragment (must be a multiple of 8-byte blocks)
length = IPV6_MAX_FRAG_SIZE;
//Copy fragment data
chunkedBufferConcat(fragment, payload, payloadOffset + offset, length);
//Fragmented packets must have the M flag set
error = ipv6SendPacket(interface, pseudoHeader, id,
offset | IPV6_FLAG_M, fragment, fragmentOffset, hopLimit);
}
//Failed to send current IP fragment?
if(error) break;
}
//Free previously allocated memory
chunkedBufferFree(fragment);
//Return status code
return error;
}