Specify local interface for TFTP sockets

[vorot]

Sometimes, UDP packets can be routed via a wrong (especially wireless) interface causing problems in TFTP protocol.
In order to prevent that, an option to specify the network interface is added.

[Callisto82]

Hi! I like most of the pull request. However, why don't you provide the local address as an optional parameter in the TftpClient constructor? That's also where the remote address is supplied, so it would kind of make sense, wouldn't it?

[vorot]

Hi! First of all, thank you for the library.

However, why don't you provide the local address as an optional parameter in the TftpClient constructor?

There are several reasons

• [main] The way I modified your library was the minimal change to fulfill my needs. I do not like to introduce new object members to simply pass a parameter.
  • The usage pattern of TftpClient assumes constructing the client object and creating the transfer object close to each other, which makes it not really important how to pass addresses.
  • If you wish, you may move this parameter to the constructor.
• It is a nightmare to support the code that uses optional parameters.
• Theoretically, I can imagine the situation when one client sends different files via different interfaces. I do not think it is going to be used by anybody, but one of my prototypes first selected where to send a file and only after that enumerated network interfaces to select the right one.