private UnixStream OpenSocket(uint?mtu)
{
sockaddr_ll sa = new sockaddr_ll();
sa.sll_family = AF_PACKET;
sa.sll_protocol = (ushort)IPAddress.HostToNetworkOrder((short)Protocol);
sa.sll_ifindex = if_nametoindex(Interface);
if (sa.sll_ifindex == 0)
{
throw new ArgumentException("The interface \"" + Interface + "\" is not valid.");
}
int fd = -1, ret = -1;
try
{
fd = socket(AF_PACKET, SOCK_RAW, sa.sll_protocol);
UnixMarshal.ThrowExceptionForLastErrorIf(fd);
ret = bind(fd, ref sa, Marshal.SizeOf(sa));
UnixMarshal.ThrowExceptionForLastErrorIf(ret);
ifreq ifr = new ifreq(Interface);
if (orig_mtu == 0)
{
ret = ioctl(fd, SIOCGIFMTU, ref ifr);
UnixMarshal.ThrowExceptionForLastErrorIf(ret);
orig_mtu = ifr.ifru_mtu;
}
if (mtu != null)
{
ifr.ifru_mtu = mtu.Value;
ret = ioctl(fd, SIOCSIFMTU, ref ifr);
UnixMarshal.ThrowExceptionForLastErrorIf(ret);
}
ret = ioctl(fd, SIOCGIFMTU, ref ifr);
UnixMarshal.ThrowExceptionForLastErrorIf(ret);
if (mtu != null && ifr.ifru_mtu != mtu.Value)
{
throw new PeachException("MTU change did not take effect.");
}
_mtu = ifr.ifru_mtu;
if (ifr.ifru_mtu > (MaxMTU - EthernetHeaderSize))
{
_bufferSize = (int)MaxMTU;
}
else
{
_bufferSize = (int)(ifr.ifru_mtu + EthernetHeaderSize);
}
var stream = new UnixStream(fd);
fd = -1;
return(stream);
}
catch (InvalidOperationException ex)
{
if (ex.InnerException != null)
{
var inner = ex.InnerException as UnixIOException;
if (inner != null && inner.ErrorCode == Errno.EPERM)
{
throw new PeachException("Access denied when opening the raw ethernet publisher. Ensure the user has the appropriate permissions.", ex);
}
}
throw;
}
finally
{
if (fd != -1)
{
Syscall.close(fd);
}
}
}
private static extern int bind(int fd, ref sockaddr_ll addr, int addrlen);