Function socreate

freebsd/kern/uipc_socket.c:505–570

* socreate returns a socket with a ref count of 1. The socket should be * closed with soclose(). */

 * closed with soclose().
 */
int
socreate(int dom, struct socket **aso, int type, int proto,
    struct ucred *cred, struct thread *td)
{
	struct protosw *prp;
	struct socket *so;
	int error;

	if (proto)
		prp = pffindproto(dom, proto, type);
	else
		prp = pffindtype(dom, type);

	if (prp == NULL) {
		/* No support for domain. */
		if (pffinddomain(dom) == NULL)
			return (EAFNOSUPPORT);
		/* No support for socket type. */
		if (proto == 0 && type != 0)
			return (EPROTOTYPE);
		return (EPROTONOSUPPORT);
	}
	if (prp->pr_usrreqs->pru_attach == NULL ||
	    prp->pr_usrreqs->pru_attach == pru_attach_notsupp)
		return (EPROTONOSUPPORT);

	if (prison_check_af(cred, prp->pr_domain->dom_family) != 0)
		return (EPROTONOSUPPORT);

	if (prp->pr_type != type)
		return (EPROTOTYPE);
	so = soalloc(CRED_TO_VNET(cred));
	if (so == NULL)
		return (ENOBUFS);

	so->so_type = type;
	so->so_cred = crhold(cred);
	if ((prp->pr_domain->dom_family == PF_INET) ||
	    (prp->pr_domain->dom_family == PF_INET6) ||
	    (prp->pr_domain->dom_family == PF_ROUTE))
		so->so_fibnum = td->td_proc->p_fibnum;
	else
		so->so_fibnum = 0;
	so->so_proto = prp;
#ifdef MAC
	mac_socket_create(cred, so);
#endif
	knlist_init(&so->so_rdsel.si_note, so, so_rdknl_lock, so_rdknl_unlock,
	    so_rdknl_assert_lock);
	knlist_init(&so->so_wrsel.si_note, so, so_wrknl_lock, so_wrknl_unlock,
	    so_wrknl_assert_lock);
	/*
	 * Auto-sizing of socket buffers is managed by the protocols and
	 * the appropriate flags must be set in the pru_attach function.
	 */
	CURVNET_SET(so->so_vnet);
	error = (*prp->pr_usrreqs->pru_attach)(so, proto, td);
	CURVNET_RESTORE();