error_t ipv4SendDatagram(NetInterface *interface, Ipv4PseudoHeader *pseudoHeader,
NetBuffer *buffer, size_t offset, uint8_t ttl)
{
error_t error;
size_t length;
uint16_t id;
//Retrieve the length of payload
length = netBufferGetLength(buffer) - offset;
//Check whether the TTL value is zero
if(ttl == 0)
{
//Use default Time-To-Live value
ttl = IPV4_DEFAULT_TTL;
}
//Identification field is primarily used to identify
//fragments of an original IP datagram
id = osAtomicInc16(&interface->ipv4Identification);
//If the payload length is smaller than the network
//interface MTU then no fragmentation is needed
if((length + sizeof(Ipv4Header)) <= interface->ipv4Config.mtu)
{
//Send data as is
error = ipv4SendPacket(interface,
pseudoHeader, id, 0, buffer, offset, ttl);
}
//If the payload length exceeds the network interface MTU
//then the device must fragment the data
else
{
#if (IPV4_FRAG_SUPPORT == ENABLED)
//Fragment IP datagram into smaller packets
error = ipv4FragmentDatagram(interface,
pseudoHeader, id, buffer, offset, ttl);
#else
//Fragmentation is not supported
error = ERROR_MESSAGE_TOO_LONG;
#endif
}
//Return status code
return error;
}
error_t ipv4SendDatagram(NetInterface *interface, Ipv4PseudoHeader *pseudoHeader,
ChunkedBuffer *buffer, size_t offset, uint8_t timeToLive)
{
error_t error;
size_t length;
uint16_t id;
//Retrieve the length of payload
length = chunkedBufferGetLength(buffer) - offset;
//Identification field is primarily used to identify
//fragments of an original IP datagram
id = osAtomicInc16(&interface->ipv4Identification);
//If the payload length is smaller than the network
//interface MTU then no fragmentation is needed
if(length <= IPV4_MAX_PAYLOAD_SIZE)
{
//Send data as is
error = ipv4SendPacket(interface,
pseudoHeader, id, 0, buffer, offset, timeToLive);
}
//If the payload length exceeds the network interface MTU
//then the device must fragment the data
else
{
#if (IPV4_FRAG_SUPPORT == ENABLED)
//Fragment IP datagram into smaller packets
error = ipv4FragmentDatagram(interface,
pseudoHeader, id, buffer, offset, timeToLive);
#else
//Fragmentation is not supported
error = ERROR_MESSAGE_TOO_LONG;
#endif
}
//Return status code
return error;
}
error_t ping(NetInterface *interface, const IpAddr *ipAddr, time_t timeout, time_t *rtt)
{
error_t error;
uint_t i;
size_t length;
uint16_t identifier;
uint16_t sequenceNumber;
time_t startTime;
time_t roundTripTime;
Socket *socket;
IcmpEchoMessage *message;
//Debug message
TRACE_INFO("Pinging %s with 64 bytes of data...\r\n", ipAddrToString(ipAddr, NULL));
//Length of the complete ICMP message including header and data
length = sizeof(IcmpEchoMessage) + PING_DATA_SIZE;
//Allocate memory buffer to hold an ICMP message
message = osMemAlloc(length);
//Failed to allocate memory?
if(!message) return ERROR_OUT_OF_MEMORY;
//Identifier field is used to help matching requests and replies
identifier = rand();
//Sequence Number field is increment each time an Echo Request is sent
sequenceNumber = osAtomicInc16(&pingSequenceNumber);
//Format ICMP Echo Request message
message->type = ICMP_TYPE_ECHO_REQUEST;
message->code = 0;
message->checksum = 0;
message->identifier = identifier;
message->sequenceNumber = sequenceNumber;
//Copy data
for(i = 0; i < PING_DATA_SIZE; i++)
message->data[i] = i;
#if (IPV4_SUPPORT == ENABLED)
//Target address is an IPv4 address?
if(ipAddr->length == sizeof(Ipv4Addr))
{
Ipv4Addr srcIpAddr;
//Select the source IPv4 address and the relevant network
//interface to use when pinging the specified host
error = ipv4SelectSourceAddr(&interface, ipAddr->ipv4Addr, &srcIpAddr);
//Any error to report?
if(error)
{
//Free previously allocated memory
osMemFree(message);
//Return the corresponding error code
return error;
}
//ICMP Echo Request message
message->type = ICMP_TYPE_ECHO_REQUEST;
//Message checksum calculation
message->checksum = ipCalcChecksum(message, length);
//Open a raw socket
socket = socketOpen(SOCKET_TYPE_RAW, SOCKET_PROTOCOL_ICMP);
}
else
#endif
#if (IPV6_SUPPORT == ENABLED)
//Target address is an IPv6 address?
if(ipAddr->length == sizeof(Ipv6Addr))
{
Ipv6PseudoHeader pseudoHeader;
//Select the source IPv6 address and the relevant network
//interface to use when pinging the specified host
error = ipv6SelectSourceAddr(&interface, &ipAddr->ipv6Addr, &pseudoHeader.srcAddr);
//Any error to report?
if(error)
{
//Free previously allocated memory
osMemFree(message);
//Return the corresponding error code
return error;
}
//ICMPv6 Echo Request message
message->type = ICMPV6_TYPE_ECHO_REQUEST;
//Format IPv6 pseudo header
pseudoHeader.destAddr = ipAddr->ipv6Addr;
pseudoHeader.length = htonl(length);
pseudoHeader.reserved = 0;
pseudoHeader.nextHeader = IPV6_ICMPV6_HEADER;
//Message checksum calculation
message->checksum = ipCalcUpperLayerChecksum(
&pseudoHeader, sizeof(Ipv6PseudoHeader), message, length);
//Open a raw socket
socket = socketOpen(SOCKET_TYPE_RAW, SOCKET_PROTOCOL_ICMPV6);
}
else
#endif
//Target address is not valid?
{
//Free previously allocated memory
osMemFree(message);
//Report an error
return ERROR_INVALID_ADDRESS;
}
//Failed to open socket?
if(!socket)
{
//Free previously allocated memory
osMemFree(message);
//Report an error
return ERROR_OPEN_FAILED;
}
//Associate the newly created socket with the relevant interface
error = socketBindToInterface(socket, interface);
//Unable to bind the socket to the desired interface?
if(error)
{
//Free previously allocated memory
osMemFree(message);
//Close socket
socketClose(socket);
//Return status code
return error;
}
//Connect the socket to the target host
error = socketConnect(socket, ipAddr, 0);
//Any error to report?
if(error)
{
//Free previously allocated memory
osMemFree(message);
//Close socket
socketClose(socket);
//Return status code
return error;
}
//Send Echo Request message
error = socketSend(socket, message, length, NULL, 0);
//Failed to send message ?
if(error)
{
//Free previously allocated memory
osMemFree(message);
//Close socket
socketClose(socket);
//Return status code
return error;
}
//Save the time at which the request was sent
startTime = osGetTickCount();
//Timeout value exceeded?
while((osGetTickCount() - startTime) < timeout)
{
//Adjust receive timeout
error = socketSetTimeout(socket, timeout);
//Any error to report?
if(error) break;
//Wait for an incoming ICMP message
error = socketReceive(socket, message,
sizeof(IcmpEchoMessage) + PING_DATA_SIZE, &length, 0);
//Any error to report?
if(error) break;
//Check message length
if(length != (sizeof(IcmpEchoMessage) + PING_DATA_SIZE))
continue;
//Verify message type
if(ipAddr->length == sizeof(Ipv4Addr) && message->type != ICMP_TYPE_ECHO_REPLY)
continue;
if(ipAddr->length == sizeof(Ipv6Addr) && message->type != ICMPV6_TYPE_ECHO_REPLY)
continue;
//Response identifier matches request identifier?
if(message->identifier != identifier)
continue;
//Make sure the sequence number is correct
if(message->sequenceNumber != sequenceNumber)
continue;
//Loop through data field
for(i = 0; i < PING_DATA_SIZE; i++)
{
//Compare received data against expected data
if(message->data[i] != i) break;
}
//Valid Echo Reply message received?
if(i == PING_DATA_SIZE)
{
//Calculate round-trip time
roundTripTime = osGetTickCount() - startTime;
//Debug message
TRACE_INFO("Echo received (round-trip time = %ums)...\r\n", roundTripTime);
//Free previously allocated memory
osMemFree(message);
//Close socket
socketClose(socket);
//Return round-trip time
if(rtt) *rtt = roundTripTime;
//No error to report
return NO_ERROR;
}
}
//Debug message
TRACE_INFO("No echo received!\r\n");
//Free previously allocated memory
osMemFree(message);
//Close socket
socketClose(socket);
//No Echo Reply received from host...
return ERROR_NO_RESPONSE;
}
