style(9) treatment following fixups.
MFC after: 3 months
This commit is contained in:
parent
ab21c0f3d0
commit
f795ce9603
@ -33,7 +33,7 @@
|
||||
*/
|
||||
|
||||
/*
|
||||
* natm.c: native mode ATM access (both aal0 and aal5).
|
||||
* natm.c: Native mode ATM access (both aal0 and aal5).
|
||||
*/
|
||||
|
||||
#include <sys/cdefs.h>
|
||||
@ -62,285 +62,295 @@ __FBSDID("$FreeBSD$");
|
||||
|
||||
#include <netnatm/natm.h>
|
||||
|
||||
static const u_long natm5_sendspace = 16*1024;
|
||||
static const u_long natm5_recvspace = 16*1024;
|
||||
static const u_long natm5_sendspace = 16*1024;
|
||||
static const u_long natm5_recvspace = 16*1024;
|
||||
|
||||
static const u_long natm0_sendspace = 16*1024;
|
||||
static const u_long natm0_recvspace = 16*1024;
|
||||
|
||||
struct mtx natm_mtx;
|
||||
static const u_long natm0_sendspace = 16*1024;
|
||||
static const u_long natm0_recvspace = 16*1024;
|
||||
|
||||
/*
|
||||
* user requests
|
||||
* netnatm global subsystem lock, protects all global data structures in
|
||||
* netnatm.
|
||||
*/
|
||||
static int natm_usr_attach(struct socket *, int, d_thread_t *);
|
||||
static void natm_usr_detach(struct socket *);
|
||||
static int natm_usr_connect(struct socket *, struct sockaddr *, d_thread_t *);
|
||||
static int natm_usr_disconnect(struct socket *);
|
||||
static int natm_usr_shutdown(struct socket *);
|
||||
static int natm_usr_send(struct socket *, int, struct mbuf *,
|
||||
struct sockaddr *, struct mbuf *, d_thread_t *);
|
||||
static int natm_usr_peeraddr(struct socket *, struct sockaddr **);
|
||||
static int natm_usr_control(struct socket *, u_long, caddr_t,
|
||||
struct ifnet *, d_thread_t *);
|
||||
static void natm_usr_abort(struct socket *);
|
||||
static int natm_usr_bind(struct socket *, struct sockaddr *, d_thread_t *);
|
||||
static int natm_usr_sockaddr(struct socket *, struct sockaddr **);
|
||||
struct mtx natm_mtx;
|
||||
|
||||
/*
|
||||
* User socket requests.
|
||||
*/
|
||||
static int natm_usr_attach(struct socket *, int, d_thread_t *);
|
||||
static void natm_usr_detach(struct socket *);
|
||||
static int natm_usr_connect(struct socket *, struct sockaddr *,
|
||||
d_thread_t *);
|
||||
static int natm_usr_disconnect(struct socket *);
|
||||
static int natm_usr_shutdown(struct socket *);
|
||||
static int natm_usr_send(struct socket *, int, struct mbuf *,
|
||||
struct sockaddr *, struct mbuf *, d_thread_t *);
|
||||
static int natm_usr_peeraddr(struct socket *, struct sockaddr **);
|
||||
static int natm_usr_control(struct socket *, u_long, caddr_t,
|
||||
struct ifnet *, d_thread_t *);
|
||||
static void natm_usr_abort(struct socket *);
|
||||
static int natm_usr_bind(struct socket *, struct sockaddr *,
|
||||
d_thread_t *);
|
||||
static int natm_usr_sockaddr(struct socket *, struct sockaddr **);
|
||||
|
||||
static int
|
||||
natm_usr_attach(struct socket *so, int proto, d_thread_t *p)
|
||||
{
|
||||
struct natmpcb *npcb;
|
||||
int error = 0;
|
||||
struct natmpcb *npcb;
|
||||
int error = 0;
|
||||
|
||||
npcb = (struct natmpcb *)so->so_pcb;
|
||||
KASSERT(npcb == NULL, ("natm_usr_attach: so_pcb != NULL"));
|
||||
npcb = (struct natmpcb *)so->so_pcb;
|
||||
KASSERT(npcb == NULL, ("natm_usr_attach: so_pcb != NULL"));
|
||||
|
||||
if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
|
||||
if (proto == PROTO_NATMAAL5)
|
||||
error = soreserve(so, natm5_sendspace, natm5_recvspace);
|
||||
else
|
||||
error = soreserve(so, natm0_sendspace, natm0_recvspace);
|
||||
if (error)
|
||||
return (error);
|
||||
}
|
||||
|
||||
so->so_pcb = npcb = npcb_alloc(M_WAITOK);
|
||||
npcb->npcb_socket = so;
|
||||
return (error);
|
||||
if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
|
||||
if (proto == PROTO_NATMAAL5)
|
||||
error = soreserve(so, natm5_sendspace,
|
||||
natm5_recvspace);
|
||||
else
|
||||
error = soreserve(so, natm0_sendspace,
|
||||
natm0_recvspace);
|
||||
if (error)
|
||||
return (error);
|
||||
}
|
||||
so->so_pcb = npcb = npcb_alloc(M_WAITOK);
|
||||
npcb->npcb_socket = so;
|
||||
return (error);
|
||||
}
|
||||
|
||||
static void
|
||||
natm_usr_detach(struct socket *so)
|
||||
{
|
||||
struct natmpcb *npcb;
|
||||
struct natmpcb *npcb;
|
||||
|
||||
npcb = (struct natmpcb *)so->so_pcb;
|
||||
KASSERT(npcb != NULL, ("natm_usr_detach: npcb == NULL"));
|
||||
npcb = (struct natmpcb *)so->so_pcb;
|
||||
KASSERT(npcb != NULL, ("natm_usr_detach: npcb == NULL"));
|
||||
|
||||
NATM_LOCK();
|
||||
npcb_free(npcb, NPCB_DESTROY); /* drain */
|
||||
so->so_pcb = NULL;
|
||||
NATM_UNLOCK();
|
||||
NATM_LOCK();
|
||||
npcb_free(npcb, NPCB_DESTROY); /* drain */
|
||||
so->so_pcb = NULL;
|
||||
NATM_UNLOCK();
|
||||
}
|
||||
|
||||
static int
|
||||
natm_usr_connect(struct socket *so, struct sockaddr *nam, d_thread_t *p)
|
||||
{
|
||||
struct natmpcb *npcb;
|
||||
struct sockaddr_natm *snatm;
|
||||
struct atmio_openvcc op;
|
||||
struct ifnet *ifp;
|
||||
int error = 0;
|
||||
int proto = so->so_proto->pr_protocol;
|
||||
struct natmpcb *npcb;
|
||||
struct sockaddr_natm *snatm;
|
||||
struct atmio_openvcc op;
|
||||
struct ifnet *ifp;
|
||||
int error = 0;
|
||||
int proto = so->so_proto->pr_protocol;
|
||||
|
||||
npcb = (struct natmpcb *)so->so_pcb;
|
||||
KASSERT(npcb != NULL, ("natm_usr_connect: npcb == NULL"));
|
||||
npcb = (struct natmpcb *)so->so_pcb;
|
||||
KASSERT(npcb != NULL, ("natm_usr_connect: npcb == NULL"));
|
||||
|
||||
/*
|
||||
* validate nam and npcb
|
||||
*/
|
||||
NATM_LOCK();
|
||||
snatm = (struct sockaddr_natm *)nam;
|
||||
if (snatm->snatm_len != sizeof(*snatm) ||
|
||||
(npcb->npcb_flags & NPCB_FREE) == 0) {
|
||||
NATM_UNLOCK();
|
||||
return (EINVAL);
|
||||
}
|
||||
if (snatm->snatm_family != AF_NATM) {
|
||||
NATM_UNLOCK();
|
||||
return (EAFNOSUPPORT);
|
||||
}
|
||||
/*
|
||||
* Validate nam and npcb.
|
||||
*/
|
||||
NATM_LOCK();
|
||||
snatm = (struct sockaddr_natm *)nam;
|
||||
if (snatm->snatm_len != sizeof(*snatm) ||
|
||||
(npcb->npcb_flags & NPCB_FREE) == 0) {
|
||||
NATM_UNLOCK();
|
||||
return (EINVAL);
|
||||
}
|
||||
if (snatm->snatm_family != AF_NATM) {
|
||||
NATM_UNLOCK();
|
||||
return (EAFNOSUPPORT);
|
||||
}
|
||||
|
||||
snatm->snatm_if[IFNAMSIZ - 1] = '\0'; /* XXX ensure null termination
|
||||
snatm->snatm_if[IFNAMSIZ - 1] = '\0'; /* XXX ensure null termination
|
||||
since ifunit() uses strcmp */
|
||||
|
||||
/*
|
||||
* convert interface string to ifp, validate.
|
||||
*/
|
||||
ifp = ifunit(snatm->snatm_if);
|
||||
if (ifp == NULL || (ifp->if_drv_flags & IFF_DRV_RUNNING) == 0) {
|
||||
NATM_UNLOCK();
|
||||
return (ENXIO);
|
||||
}
|
||||
if (ifp->if_output != atm_output) {
|
||||
NATM_UNLOCK();
|
||||
return (EAFNOSUPPORT);
|
||||
}
|
||||
/*
|
||||
* Convert interface string to ifp, validate.
|
||||
*/
|
||||
ifp = ifunit(snatm->snatm_if);
|
||||
if (ifp == NULL || (ifp->if_drv_flags & IFF_DRV_RUNNING) == 0) {
|
||||
NATM_UNLOCK();
|
||||
return (ENXIO);
|
||||
}
|
||||
if (ifp->if_output != atm_output) {
|
||||
NATM_UNLOCK();
|
||||
return (EAFNOSUPPORT);
|
||||
}
|
||||
|
||||
/*
|
||||
* register us with the NATM PCB layer
|
||||
*/
|
||||
if (npcb_add(npcb, ifp, snatm->snatm_vci, snatm->snatm_vpi) != npcb) {
|
||||
/*
|
||||
* Register us with the NATM PCB layer.
|
||||
*/
|
||||
if (npcb_add(npcb, ifp, snatm->snatm_vci, snatm->snatm_vpi) != npcb) {
|
||||
NATM_UNLOCK();
|
||||
return (EADDRINUSE);
|
||||
}
|
||||
|
||||
/*
|
||||
* Open the channel.
|
||||
*
|
||||
* XXXRW: Eventually desirable to hold mutex over ioctl?
|
||||
*/
|
||||
bzero(&op, sizeof(op));
|
||||
op.rxhand = npcb;
|
||||
op.param.flags = ATMIO_FLAG_PVC;
|
||||
op.param.vpi = npcb->npcb_vpi;
|
||||
op.param.vci = npcb->npcb_vci;
|
||||
op.param.rmtu = op.param.tmtu = ifp->if_mtu;
|
||||
op.param.aal = (proto == PROTO_NATMAAL5) ? ATMIO_AAL_5 : ATMIO_AAL_0;
|
||||
op.param.traffic = ATMIO_TRAFFIC_UBR;
|
||||
NATM_UNLOCK();
|
||||
return (EADDRINUSE);
|
||||
}
|
||||
|
||||
/*
|
||||
* Open the channel.
|
||||
*
|
||||
* XXXRW: Eventually desirable to hold mutex over ioctl?
|
||||
*/
|
||||
bzero(&op, sizeof(op));
|
||||
op.rxhand = npcb;
|
||||
op.param.flags = ATMIO_FLAG_PVC;
|
||||
op.param.vpi = npcb->npcb_vpi;
|
||||
op.param.vci = npcb->npcb_vci;
|
||||
op.param.rmtu = op.param.tmtu = ifp->if_mtu;
|
||||
op.param.aal = (proto == PROTO_NATMAAL5) ? ATMIO_AAL_5 : ATMIO_AAL_0;
|
||||
op.param.traffic = ATMIO_TRAFFIC_UBR;
|
||||
NATM_UNLOCK();
|
||||
|
||||
IFF_LOCKGIANT(ifp);
|
||||
if (ifp->if_ioctl == NULL ||
|
||||
ifp->if_ioctl(ifp, SIOCATMOPENVCC, (caddr_t)&op) != 0) {
|
||||
IFF_LOCKGIANT(ifp);
|
||||
if (ifp->if_ioctl == NULL ||
|
||||
ifp->if_ioctl(ifp, SIOCATMOPENVCC, (caddr_t)&op) != 0) {
|
||||
IFF_UNLOCKGIANT(ifp);
|
||||
return (EIO);
|
||||
}
|
||||
IFF_UNLOCKGIANT(ifp);
|
||||
return (EIO);
|
||||
}
|
||||
IFF_UNLOCKGIANT(ifp);
|
||||
soisconnected(so);
|
||||
return (error);
|
||||
soisconnected(so);
|
||||
return (error);
|
||||
}
|
||||
|
||||
static int
|
||||
natm_usr_disconnect(struct socket *so)
|
||||
{
|
||||
struct natmpcb *npcb;
|
||||
struct atmio_closevcc cl;
|
||||
struct ifnet *ifp;
|
||||
int error = 0;
|
||||
struct natmpcb *npcb;
|
||||
struct atmio_closevcc cl;
|
||||
struct ifnet *ifp;
|
||||
int error = 0;
|
||||
|
||||
npcb = (struct natmpcb *)so->so_pcb;
|
||||
KASSERT(npcb != NULL, ("natm_usr_disconnect: npcb == NULL"));
|
||||
npcb = (struct natmpcb *)so->so_pcb;
|
||||
KASSERT(npcb != NULL, ("natm_usr_disconnect: npcb == NULL"));
|
||||
|
||||
NATM_LOCK();
|
||||
if ((npcb->npcb_flags & NPCB_CONNECTED) == 0) {
|
||||
NATM_LOCK();
|
||||
if ((npcb->npcb_flags & NPCB_CONNECTED) == 0) {
|
||||
NATM_UNLOCK();
|
||||
printf("natm: disconnected check\n");
|
||||
return (EIO);
|
||||
}
|
||||
ifp = npcb->npcb_ifp;
|
||||
|
||||
/*
|
||||
* Disable rx.
|
||||
*
|
||||
* XXXRW: Eventually desirable to hold mutex over ioctl?
|
||||
*/
|
||||
cl.vpi = npcb->npcb_vpi;
|
||||
cl.vci = npcb->npcb_vci;
|
||||
NATM_UNLOCK();
|
||||
printf("natm: disconnected check\n");
|
||||
return (EIO);
|
||||
}
|
||||
ifp = npcb->npcb_ifp;
|
||||
|
||||
/*
|
||||
* Disable rx.
|
||||
*
|
||||
* XXXRW: Eventually desirable to hold mutex over ioctl?
|
||||
*/
|
||||
cl.vpi = npcb->npcb_vpi;
|
||||
cl.vci = npcb->npcb_vci;
|
||||
NATM_UNLOCK();
|
||||
if (ifp->if_ioctl != NULL) {
|
||||
IFF_LOCKGIANT(ifp);
|
||||
ifp->if_ioctl(ifp, SIOCATMCLOSEVCC, (caddr_t)&cl);
|
||||
IFF_UNLOCKGIANT(ifp);
|
||||
}
|
||||
soisdisconnected(so);
|
||||
return (error);
|
||||
if (ifp->if_ioctl != NULL) {
|
||||
IFF_LOCKGIANT(ifp);
|
||||
ifp->if_ioctl(ifp, SIOCATMCLOSEVCC, (caddr_t)&cl);
|
||||
IFF_UNLOCKGIANT(ifp);
|
||||
}
|
||||
soisdisconnected(so);
|
||||
return (error);
|
||||
}
|
||||
|
||||
static int
|
||||
natm_usr_shutdown(struct socket *so)
|
||||
{
|
||||
socantsendmore(so);
|
||||
return (0);
|
||||
|
||||
socantsendmore(so);
|
||||
return (0);
|
||||
}
|
||||
|
||||
static int
|
||||
natm_usr_send(struct socket *so, int flags, struct mbuf *m,
|
||||
struct sockaddr *nam, struct mbuf *control, d_thread_t *p)
|
||||
struct sockaddr *nam, struct mbuf *control, d_thread_t *p)
|
||||
{
|
||||
struct natmpcb *npcb;
|
||||
struct atm_pseudohdr *aph;
|
||||
int error = 0;
|
||||
int proto = so->so_proto->pr_protocol;
|
||||
struct natmpcb *npcb;
|
||||
struct atm_pseudohdr *aph;
|
||||
int error = 0;
|
||||
int proto = so->so_proto->pr_protocol;
|
||||
|
||||
npcb = (struct natmpcb *)so->so_pcb;
|
||||
KASSERT(npcb != NULL, ("natm_usr_send: npcb == NULL"));
|
||||
npcb = (struct natmpcb *)so->so_pcb;
|
||||
KASSERT(npcb != NULL, ("natm_usr_send: npcb == NULL"));
|
||||
|
||||
NATM_LOCK();
|
||||
if (control && control->m_len) {
|
||||
NATM_LOCK();
|
||||
if (control && control->m_len) {
|
||||
NATM_UNLOCK();
|
||||
m_freem(control);
|
||||
m_freem(m);
|
||||
return (EINVAL);
|
||||
}
|
||||
|
||||
/*
|
||||
* Send the data. We must put an atm_pseudohdr on first.
|
||||
*/
|
||||
M_PREPEND(m, sizeof(*aph), M_DONTWAIT);
|
||||
if (m == NULL) {
|
||||
NATM_UNLOCK();
|
||||
m_freem(control);
|
||||
return (ENOBUFS);
|
||||
}
|
||||
aph = mtod(m, struct atm_pseudohdr *);
|
||||
ATM_PH_VPI(aph) = npcb->npcb_vpi;
|
||||
ATM_PH_SETVCI(aph, npcb->npcb_vci);
|
||||
ATM_PH_FLAGS(aph) = (proto == PROTO_NATMAAL5) ? ATM_PH_AAL5 : 0;
|
||||
error = atm_output(npcb->npcb_ifp, m, NULL, NULL);
|
||||
NATM_UNLOCK();
|
||||
m_freem(control);
|
||||
m_freem(m);
|
||||
return (EINVAL);
|
||||
}
|
||||
|
||||
/*
|
||||
* send the data. we must put an atm_pseudohdr on first
|
||||
*/
|
||||
M_PREPEND(m, sizeof(*aph), M_DONTWAIT);
|
||||
if (m == NULL) {
|
||||
NATM_UNLOCK();
|
||||
m_freem(control);
|
||||
return (ENOBUFS);
|
||||
}
|
||||
aph = mtod(m, struct atm_pseudohdr *);
|
||||
ATM_PH_VPI(aph) = npcb->npcb_vpi;
|
||||
ATM_PH_SETVCI(aph, npcb->npcb_vci);
|
||||
ATM_PH_FLAGS(aph) = (proto == PROTO_NATMAAL5) ? ATM_PH_AAL5 : 0;
|
||||
error = atm_output(npcb->npcb_ifp, m, NULL, NULL);
|
||||
NATM_UNLOCK();
|
||||
return (error);
|
||||
return (error);
|
||||
}
|
||||
|
||||
static int
|
||||
natm_usr_peeraddr(struct socket *so, struct sockaddr **nam)
|
||||
{
|
||||
struct natmpcb *npcb;
|
||||
struct sockaddr_natm *snatm, ssnatm;
|
||||
struct natmpcb *npcb;
|
||||
struct sockaddr_natm *snatm, ssnatm;
|
||||
|
||||
npcb = (struct natmpcb *)so->so_pcb;
|
||||
KASSERT(npcb != NULL, ("natm_usr_peeraddr: npcb == NULL"));
|
||||
npcb = (struct natmpcb *)so->so_pcb;
|
||||
KASSERT(npcb != NULL, ("natm_usr_peeraddr: npcb == NULL"));
|
||||
|
||||
NATM_LOCK();
|
||||
snatm = &ssnatm;
|
||||
bzero(snatm, sizeof(*snatm));
|
||||
snatm->snatm_len = sizeof(*snatm);
|
||||
snatm->snatm_family = AF_NATM;
|
||||
strlcpy(snatm->snatm_if, npcb->npcb_ifp->if_xname,
|
||||
sizeof(snatm->snatm_if));
|
||||
snatm->snatm_vci = npcb->npcb_vci;
|
||||
snatm->snatm_vpi = npcb->npcb_vpi;
|
||||
NATM_UNLOCK();
|
||||
*nam = sodupsockaddr((struct sockaddr *)snatm, M_WAITOK);
|
||||
return (0);
|
||||
NATM_LOCK();
|
||||
snatm = &ssnatm;
|
||||
bzero(snatm, sizeof(*snatm));
|
||||
snatm->snatm_len = sizeof(*snatm);
|
||||
snatm->snatm_family = AF_NATM;
|
||||
strlcpy(snatm->snatm_if, npcb->npcb_ifp->if_xname,
|
||||
sizeof(snatm->snatm_if));
|
||||
snatm->snatm_vci = npcb->npcb_vci;
|
||||
snatm->snatm_vpi = npcb->npcb_vpi;
|
||||
NATM_UNLOCK();
|
||||
*nam = sodupsockaddr((struct sockaddr *)snatm, M_WAITOK);
|
||||
return (0);
|
||||
}
|
||||
|
||||
static int
|
||||
natm_usr_control(struct socket *so, u_long cmd, caddr_t arg,
|
||||
struct ifnet *ifp, d_thread_t *p)
|
||||
struct ifnet *ifp, d_thread_t *p)
|
||||
{
|
||||
struct natmpcb *npcb;
|
||||
int error;
|
||||
struct natmpcb *npcb;
|
||||
int error;
|
||||
|
||||
npcb = (struct natmpcb *)so->so_pcb;
|
||||
KASSERT(npcb != NULL, ("natm_usr_control: npcb == NULL"));
|
||||
npcb = (struct natmpcb *)so->so_pcb;
|
||||
KASSERT(npcb != NULL, ("natm_usr_control: npcb == NULL"));
|
||||
|
||||
if (ifp == NULL || ifp->if_ioctl == NULL)
|
||||
return (EOPNOTSUPP);
|
||||
|
||||
IFF_LOCKGIANT(ifp);
|
||||
error = ((*ifp->if_ioctl)(ifp, cmd, arg));
|
||||
IFF_UNLOCKGIANT(ifp);
|
||||
return (error);
|
||||
if (ifp == NULL || ifp->if_ioctl == NULL)
|
||||
return (EOPNOTSUPP);
|
||||
IFF_LOCKGIANT(ifp);
|
||||
error = ((*ifp->if_ioctl)(ifp, cmd, arg));
|
||||
IFF_UNLOCKGIANT(ifp);
|
||||
return (error);
|
||||
}
|
||||
|
||||
static void
|
||||
natm_usr_abort(struct socket *so)
|
||||
{
|
||||
natm_usr_detach(so);
|
||||
|
||||
natm_usr_detach(so);
|
||||
}
|
||||
|
||||
static int
|
||||
natm_usr_bind(struct socket *so, struct sockaddr *nam, d_thread_t *p)
|
||||
{
|
||||
return (EOPNOTSUPP);
|
||||
|
||||
return (EOPNOTSUPP);
|
||||
}
|
||||
|
||||
static int
|
||||
natm_usr_sockaddr(struct socket *so, struct sockaddr **nam)
|
||||
{
|
||||
return (EOPNOTSUPP);
|
||||
|
||||
return (EOPNOTSUPP);
|
||||
}
|
||||
|
||||
/* xxx - should be const */
|
||||
@ -361,9 +371,9 @@ struct pr_usrreqs natm_usrreqs = {
|
||||
/*
|
||||
* natmintr: interrupt
|
||||
*
|
||||
* note: we expect a socket pointer in rcvif rather than an interface
|
||||
* pointer. we can get the interface pointer from the so's PCB if
|
||||
* we really need it.
|
||||
* Note: we expect a socket pointer in rcvif rather than an interface
|
||||
* pointer. We can get the interface pointer from the so's PCB if we really
|
||||
* need it.
|
||||
*/
|
||||
void
|
||||
natmintr(struct mbuf *m)
|
||||
@ -428,6 +438,7 @@ natmintr(struct mbuf *m)
|
||||
int
|
||||
natm0_sysctl(SYSCTL_HANDLER_ARGS)
|
||||
{
|
||||
|
||||
/* All sysctl names at this level are terminal. */
|
||||
return (ENOENT);
|
||||
}
|
||||
@ -439,6 +450,7 @@ natm0_sysctl(SYSCTL_HANDLER_ARGS)
|
||||
int
|
||||
natm5_sysctl(SYSCTL_HANDLER_ARGS)
|
||||
{
|
||||
|
||||
/* All sysctl names at this level are terminal. */
|
||||
return (ENOENT);
|
||||
}
|
||||
|
Loading…
Reference in New Issue
Block a user