Support getpeername and getsockname syscalls

[ShuochengWang]

No description provided.

[ShuochengWang]

getsockname for different states:

• Init
  • bind: addr is Some, return it
  • not bind: addr is None, get addr from host but don't store this addr (This addr will be invalid in later state, we should not store it)
• Connect: get addr from host but don't store this addr
• Connected: return addr if it's Some, else get addr from host and store this addr
• Listen: return addr if it's Some, else get addr from host and store this addr

[tatetian]

LGTM. Thanks for the contribution!