usr/src/sys/sys/socket.h

/*      socket.h        4.5     81/11/14        */

/*
 * Externally visible attributes of sockets.
 */

/*
 * Socket types.
 *
 * The kernel implement these abstract (session-layer) socket
 * services, with extra protocol on top of network services
 * if necessary.
 */
#define SOCK_STREAM     0               /* stream socket */
#define SOCK_DGRAM      1               /* datagram socket */
#define SOCK_RAW        2               /* raw-protocol interface */
#define SOCK_RDM        3               /* reliably-delivered message */

/*
 * Option flags per-socket.
 */
#define SO_DEBUG        0x01            /* turn on debugging info recording */
#define SO_ACCEPTCONN   0x02            /* willing to accept connection */
#define SO_NBIO         0x04            /* don't block on this socket */
#define SO_INTNOTIFY    0x08            /* interrupt when data available */
#define SO_NEWFDONCONN  0x10            /* give new fd's for each connect */