error_t ipv4LeaveMulticastGroup(NetInterface *interface, Ipv4Addr groupAddr)
{
uint_t i;
uint_t j;
MacAddr macAddr;
//Ensure the specified IPv4 address is a multicast address
if(!ipv4IsMulticastAddr(groupAddr))
return ERROR_INVALID_ADDRESS;
//Acquire exclusive access to the IPv4 filter table
osAcquireMutex(&interface->ipv4FilterMutex);
//Loop through filter table entries
for(i = 0; i < interface->ipv4FilterSize; i++)
{
//Specified IPv4 address found?
if(interface->ipv4Filter[i].addr == groupAddr)
{
//Decrement the reference count
interface->ipv4Filter[i].refCount--;
//Remove the entry if the reference count drops to zero
if(interface->ipv4Filter[i].refCount < 1)
{
#if (IGMP_SUPPORT == ENABLED)
//Report group membership termination
igmpLeaveGroup(interface, &interface->ipv4Filter[i]);
#endif
//Map the multicast IPv4 address to a MAC-layer address
ipv4MapMulticastAddrToMac(groupAddr, &macAddr);
#if (ETH_SUPPORT == ENABLED)
//Drop the corresponding address from the MAC filter table
ethDropMulticastAddr(interface, &macAddr);
#endif
//Adjust the size of the IPv4 filter table
interface->ipv4FilterSize--;
//Remove the corresponding entry
for(j = i; j < interface->ipv4FilterSize; j++)
interface->ipv4Filter[j] = interface->ipv4Filter[j + 1];
}
//Release exclusive access to the IPv4 filter table
osReleaseMutex(&interface->ipv4FilterMutex);
//No error to report
return NO_ERROR;
}
}
//Release exclusive access to the IPv4 filter table
osReleaseMutex(&interface->ipv4FilterMutex);
//The specified IPv4 address does not exist
return ERROR_FAILURE;
}
error_t ipv4JoinMulticastGroup(NetInterface *interface, Ipv4Addr groupAddr)
{
error_t error;
uint_t i;
MacAddr macAddr;
//Ensure the specified IPv4 address is a multicast address
if(!ipv4IsMulticastAddr(groupAddr))
return ERROR_INVALID_ADDRESS;
//Acquire exclusive access to the IPv4 filter table
osMutexAcquire(interface->ipv4FilterMutex);
//Loop through filter table entries
for(i = 0; i < interface->ipv4FilterSize; i++)
{
//Check whether the table already contains the specified IPv4 address
if(interface->ipv4Filter[i].addr == groupAddr)
{
//Increment the reference count
interface->ipv4Filter[i].refCount++;
//Release exclusive access to the IPv4 filter table
osMutexRelease(interface->ipv4FilterMutex);
//No error to report
return NO_ERROR;
}
}
//The IPv4 filter table is full ?
if(i >= IPV4_FILTER_MAX_SIZE)
{
//Release exclusive access to the IPv4 filter table
osMutexRelease(interface->ipv4FilterMutex);
//A new entry cannot be added
return ERROR_FAILURE;
}
//Map the multicast IPv4 address to a MAC-layer address
ipv4MapMulticastAddrToMac(groupAddr, &macAddr);
//Add the corresponding address to the MAC filter table
error = ethAcceptMulticastAddr(interface, &macAddr);
//Ensure the MAC filter table was successfully updated
if(!error)
{
//Now we can safely add a new entry to the table
interface->ipv4Filter[i].addr = groupAddr;
//Initialize the reference count
interface->ipv4Filter[i].refCount = 1;
//Adjust the size of the IPv4 filter table
interface->ipv4FilterSize++;
#if (IGMP_SUPPORT == ENABLED)
//Report multicast group membership to the router
igmpJoinGroup(interface, &interface->ipv4Filter[i]);
#endif
}
//Release exclusive access to the IPv4 filter table
osMutexRelease(interface->ipv4FilterMutex);
//Return status code
return error;
}
error_t ipv4SendPacket(NetInterface *interface, Ipv4PseudoHeader *pseudoHeader,
uint16_t fragId, uint16_t fragOffset, ChunkedBuffer *buffer, size_t offset, uint8_t timeToLive)
{
error_t error;
size_t length;
Ipv4Addr destIpAddr = 0;
MacAddr destMacAddr;
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 = chunkedBufferGetLength(buffer) - offset;
//Point to the IPv4 header
packet = chunkedBufferAt(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 = timeToLive;
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
error = ERROR_INVALID_ADDRESS;
}
//Destination address is the loopback address?
else if(pseudoHeader->destAddr == IPV4_LOOPBACK_ADDR)
{
//Not yet implemented...
error = ERROR_NOT_IMPLEMENTED;
}
//Destination address is a broadcast address?
else 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 (%u 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 (%u 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");
}
//Return status code
return error;
}
