OMRSOCK API: Implement omrsock_connect and omrsock_accept functions on Unix

[caohaley]

Working on Issue: #4102
/cc @rwy0717 @mpirvu

Omrsock functions to be implemented:
omrsock_connect, omrsock_accept

Descriptions

omrsock_connect is usually called by the client that wishes to connect to a server.
If the initiating socket is for datagram connections, omrsock_connect will set up peer address but no connection is actually made. When peer address is set, this datagram socket will be only for sending and receiving from the peer address. The peer can be switched with consecutive calls to omrsock_connect and can be disconnected from the peer with a call to omrsock_connect with NULL address.
If the initiating socket is for stream connection, omrsock_connect will attempt to establish a connection with the server address passed in. It will attempt to connect for a time interval and either fail or succeed. The nonblock functionality will be implemented and added in the future.

omrsock_accept is called to accept the first connection in the queue of pending connections. It will then return a new socket specifically for that connection.

Implementation Details:

The omrsock_connect function will be set up to call the system socket api connect function. It will be tested to see if it works on all Unix systems and if there is anything to be added.

The omrsock_accept function will call the system socket api accept function and will allocate memory for a new OMRSocket structure for the newly returned socket descriptor for the connection. This socket structure will be released when the user calls omrsock_close to close the socket. It is the user's responsibility to close the sockets at the end of their program.

Unix Progress Tracker

• Implement omrsock_getaddrinfo_create_hints (and socket per thread buffer). PR:Added a per thread buffer and related tests for OMR socket API #4555

• Implement OMRAddrInfoNode element extraction (omrsock_getaddrinfo_length, family, socktype, protocol). Issue:OMRSOCK API: Implement OMRAddrInfoNode Element Extraction Functions on Unix #4745, PR:Added Unix Implementations for Element Extracting Functions in OMRSOCK API #4738

• Implementing omrsock_getaddrinfo. Issue:OMRSOCK API: Implement omrsock_getaddrinfo function on Unix #4794 PR:Added Unix Implementation for omrsock_getaddrinfo and omrsock_freeaddrinfo in OMRSOCK API #4832

• Implementing omrsock_socket (constants definition of socket types) and omrsock_close. Issue:OMRSOCK API: Implement omrsock_socket Function on Unix #4795 PRs:Added constants for Unix Implementations in OMRSOCK API #4878, Added Unix Implementations for omrsock_socket and omrsock_close in OMRSOCK API #4887

• Implementing omrsock_bind and omrsock_listen Issue:OMRSOCK API: Implement omrsock_bind and omrsock_listen functions on Unix #4919 PRs:Setting Up Socket Address for Bind and Listen #4974, Implement omrsock_bind and omrsock_listen on Unix #5034

• Implementing omrsock_connect and omrsock_accept

• Implementing omrsock_send and receive

• Implementing omrsock_sendto and recvfrom