Read from a serial port (TTY), Linux

I need a Linux program to read from a serial port and write to? a TCP/IP socket. I have source code in C for a Linux program (cmd line) that reads from a serial port (TTY). I have source code in C for a Windows app (cmd line) that sends TCP data? to a Linux app. I need to port the TCP? sending code from Windows? into the Linux code reading that reads from the serial port. If this works out, I'll want to port it to Windows and then I have another? small project based around this.