Constant netlink_packet_sock_diag::constants::UDIAG_SHOW_PEER

pub const UDIAG_SHOW_PEER: u32 = 1 << UNIX_DIAG_PEER; // 0x0000_0004u32

The attribute reported in answer to this request is UNIX_DIAG_PEER, which carries the peer’s inode number. This attribute is reported for connected sockets only.