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|struct sockaddr	| Abstract for AF_INET,AF_UNIX.
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|struct sockaddr_in	| Concrete for AF_INET => IPv4 addr + port
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|struct sockaddr_un	| Concrete for AF_UNIX => file path
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|struct sockaddr_storage| Abstract for AF_INET,AF_INET6 (AF_UNIX?)
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|struct sockaddr_in6	| Concrete for AF_INET6 => IPv6 addr+port+flw_inf+scp_id
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|struct in_addr		| Concrete IPv4 address format ( NOT include port)
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|struct in6_addr	| Concrete IPv6 address format (NOT include port)
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