root/net/atm/svc.c
// SPDX-License-Identifier: GPL-2.0
/* net/atm/svc.c - ATM SVC sockets */

/* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */

#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__

#include <linux/string.h>
#include <linux/net.h>          /* struct socket, struct proto_ops */
#include <linux/errno.h>        /* error codes */
#include <linux/kernel.h>       /* printk */
#include <linux/skbuff.h>
#include <linux/wait.h>
#include <linux/sched/signal.h>
#include <linux/fcntl.h>        /* O_NONBLOCK */
#include <linux/init.h>
#include <linux/atm.h>          /* ATM stuff */
#include <linux/atmsap.h>
#include <linux/atmsvc.h>
#include <linux/atmdev.h>
#include <linux/bitops.h>
#include <net/sock.h>           /* for sock_no_* */
#include <linux/uaccess.h>
#include <linux/export.h>

#include "resources.h"
#include "common.h"             /* common for PVCs and SVCs */
#include "signaling.h"
#include "addr.h"

#ifdef CONFIG_COMPAT
/* It actually takes struct sockaddr_atmsvc, not struct atm_iobuf */
#define COMPAT_ATM_ADDPARTY _IOW('a', ATMIOC_SPECIAL + 4, struct compat_atm_iobuf)
#endif

static int svc_create(struct net *net, struct socket *sock, int protocol,
                      int kern);

/*
 * Note: since all this is still nicely synchronized with the signaling demon,
 *       there's no need to protect sleep loops with clis. If signaling is
 *       moved into the kernel, that would change.
 */


static int svc_shutdown(struct socket *sock, int how)
{
        return 0;
}

static void svc_disconnect(struct atm_vcc *vcc)
{
        DEFINE_WAIT(wait);
        struct sk_buff *skb;
        struct sock *sk = sk_atm(vcc);

        pr_debug("%p\n", vcc);
        if (test_bit(ATM_VF_REGIS, &vcc->flags)) {
                sigd_enq(vcc, as_close, NULL, NULL, NULL);
                for (;;) {
                        prepare_to_wait(sk_sleep(sk), &wait, TASK_UNINTERRUPTIBLE);
                        if (test_bit(ATM_VF_RELEASED, &vcc->flags) || !sigd)
                                break;
                        schedule();
                }
                finish_wait(sk_sleep(sk), &wait);
        }
        /* beware - socket is still in use by atmsigd until the last
           as_indicate has been answered */
        while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
                atm_return(vcc, skb->truesize);
                pr_debug("LISTEN REL\n");
                sigd_enq2(NULL, as_reject, vcc, NULL, NULL, &vcc->qos, 0);
                dev_kfree_skb(skb);
        }
        clear_bit(ATM_VF_REGIS, &vcc->flags);
        /* ... may retry later */
}

static int svc_release(struct socket *sock)
{
        struct sock *sk = sock->sk;
        struct atm_vcc *vcc;

        if (sk) {
                vcc = ATM_SD(sock);
                pr_debug("%p\n", vcc);
                clear_bit(ATM_VF_READY, &vcc->flags);
                /*
                 * VCC pointer is used as a reference,
                 * so we must not free it (thereby subjecting it to re-use)
                 * before all pending connections are closed
                 */
                svc_disconnect(vcc);
                vcc_release(sock);
        }
        return 0;
}

static int svc_bind(struct socket *sock, struct sockaddr_unsized *sockaddr,
                    int sockaddr_len)
{
        DEFINE_WAIT(wait);
        struct sock *sk = sock->sk;
        struct sockaddr_atmsvc *addr;
        struct atm_vcc *vcc;
        int error;

        if (sockaddr_len != sizeof(struct sockaddr_atmsvc))
                return -EINVAL;
        lock_sock(sk);
        if (sock->state == SS_CONNECTED) {
                error = -EISCONN;
                goto out;
        }
        if (sock->state != SS_UNCONNECTED) {
                error = -EINVAL;
                goto out;
        }
        vcc = ATM_SD(sock);
        addr = (struct sockaddr_atmsvc *) sockaddr;
        if (addr->sas_family != AF_ATMSVC) {
                error = -EAFNOSUPPORT;
                goto out;
        }
        clear_bit(ATM_VF_BOUND, &vcc->flags);
            /* failing rebind will kill old binding */
        /* @@@ check memory (de)allocation on rebind */
        if (!test_bit(ATM_VF_HASQOS, &vcc->flags)) {
                error = -EBADFD;
                goto out;
        }
        vcc->local = *addr;
        set_bit(ATM_VF_WAITING, &vcc->flags);
        sigd_enq(vcc, as_bind, NULL, NULL, &vcc->local);
        for (;;) {
                prepare_to_wait(sk_sleep(sk), &wait, TASK_UNINTERRUPTIBLE);
                if (!test_bit(ATM_VF_WAITING, &vcc->flags) || !sigd)
                        break;
                schedule();
        }
        finish_wait(sk_sleep(sk), &wait);
        clear_bit(ATM_VF_REGIS, &vcc->flags); /* doesn't count */
        if (!sigd) {
                error = -EUNATCH;
                goto out;
        }
        if (!sk->sk_err)
                set_bit(ATM_VF_BOUND, &vcc->flags);
        error = -sk->sk_err;
out:
        release_sock(sk);
        return error;
}

static int svc_connect(struct socket *sock, struct sockaddr_unsized *sockaddr,
                       int sockaddr_len, int flags)
{
        DEFINE_WAIT(wait);
        struct sock *sk = sock->sk;
        struct sockaddr_atmsvc *addr;
        struct atm_vcc *vcc = ATM_SD(sock);
        int error;

        pr_debug("%p\n", vcc);
        lock_sock(sk);
        if (sockaddr_len != sizeof(struct sockaddr_atmsvc)) {
                error = -EINVAL;
                goto out;
        }

        switch (sock->state) {
        default:
                error = -EINVAL;
                goto out;
        case SS_CONNECTED:
                error = -EISCONN;
                goto out;
        case SS_CONNECTING:
                if (test_bit(ATM_VF_WAITING, &vcc->flags)) {
                        error = -EALREADY;
                        goto out;
                }
                sock->state = SS_UNCONNECTED;
                if (sk->sk_err) {
                        error = -sk->sk_err;
                        goto out;
                }
                break;
        case SS_UNCONNECTED:
                addr = (struct sockaddr_atmsvc *) sockaddr;
                if (addr->sas_family != AF_ATMSVC) {
                        error = -EAFNOSUPPORT;
                        goto out;
                }
                if (!test_bit(ATM_VF_HASQOS, &vcc->flags)) {
                        error = -EBADFD;
                        goto out;
                }
                if (vcc->qos.txtp.traffic_class == ATM_ANYCLASS ||
                    vcc->qos.rxtp.traffic_class == ATM_ANYCLASS) {
                        error = -EINVAL;
                        goto out;
                }
                if (!vcc->qos.txtp.traffic_class &&
                    !vcc->qos.rxtp.traffic_class) {
                        error = -EINVAL;
                        goto out;
                }
                vcc->remote = *addr;
                set_bit(ATM_VF_WAITING, &vcc->flags);
                sigd_enq(vcc, as_connect, NULL, NULL, &vcc->remote);
                if (flags & O_NONBLOCK) {
                        sock->state = SS_CONNECTING;
                        error = -EINPROGRESS;
                        goto out;
                }
                error = 0;
                prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
                while (test_bit(ATM_VF_WAITING, &vcc->flags) && sigd) {
                        schedule();
                        if (!signal_pending(current)) {
                                prepare_to_wait(sk_sleep(sk), &wait,
                                                TASK_INTERRUPTIBLE);
                                continue;
                        }
                        pr_debug("*ABORT*\n");
                        /*
                         * This is tricky:
                         *   Kernel ---close--> Demon
                         *   Kernel <--close--- Demon
                         * or
                         *   Kernel ---close--> Demon
                         *   Kernel <--error--- Demon
                         * or
                         *   Kernel ---close--> Demon
                         *   Kernel <--okay---- Demon
                         *   Kernel <--close--- Demon
                         */
                        sigd_enq(vcc, as_close, NULL, NULL, NULL);
                        while (test_bit(ATM_VF_WAITING, &vcc->flags) && sigd) {
                                prepare_to_wait(sk_sleep(sk), &wait,
                                                TASK_INTERRUPTIBLE);
                                schedule();
                        }
                        if (!sk->sk_err)
                                while (!test_bit(ATM_VF_RELEASED, &vcc->flags) &&
                                       sigd) {
                                        prepare_to_wait(sk_sleep(sk), &wait,
                                                        TASK_INTERRUPTIBLE);
                                        schedule();
                                }
                        clear_bit(ATM_VF_REGIS, &vcc->flags);
                        clear_bit(ATM_VF_RELEASED, &vcc->flags);
                        clear_bit(ATM_VF_CLOSE, &vcc->flags);
                            /* we're gone now but may connect later */
                        error = -EINTR;
                        break;
                }
                finish_wait(sk_sleep(sk), &wait);
                if (error)
                        goto out;
                if (!sigd) {
                        error = -EUNATCH;
                        goto out;
                }
                if (sk->sk_err) {
                        error = -sk->sk_err;
                        goto out;
                }
        }

        vcc->qos.txtp.max_pcr = SELECT_TOP_PCR(vcc->qos.txtp);
        vcc->qos.txtp.pcr = 0;
        vcc->qos.txtp.min_pcr = 0;

        error = vcc_connect(sock, vcc->itf, vcc->vpi, vcc->vci);
        if (!error)
                sock->state = SS_CONNECTED;
        else
                (void)svc_disconnect(vcc);
out:
        release_sock(sk);
        return error;
}

static int svc_listen(struct socket *sock, int backlog)
{
        DEFINE_WAIT(wait);
        struct sock *sk = sock->sk;
        struct atm_vcc *vcc = ATM_SD(sock);
        int error;

        pr_debug("%p\n", vcc);
        lock_sock(sk);
        /* let server handle listen on unbound sockets */
        if (test_bit(ATM_VF_SESSION, &vcc->flags)) {
                error = -EINVAL;
                goto out;
        }
        if (test_bit(ATM_VF_LISTEN, &vcc->flags)) {
                error = -EADDRINUSE;
                goto out;
        }
        set_bit(ATM_VF_WAITING, &vcc->flags);
        sigd_enq(vcc, as_listen, NULL, NULL, &vcc->local);
        for (;;) {
                prepare_to_wait(sk_sleep(sk), &wait, TASK_UNINTERRUPTIBLE);
                if (!test_bit(ATM_VF_WAITING, &vcc->flags) || !sigd)
                        break;
                schedule();
        }
        finish_wait(sk_sleep(sk), &wait);
        if (!sigd) {
                error = -EUNATCH;
                goto out;
        }
        set_bit(ATM_VF_LISTEN, &vcc->flags);
        vcc_insert_socket(sk);
        sk->sk_max_ack_backlog = backlog > 0 ? backlog : ATM_BACKLOG_DEFAULT;
        error = -sk->sk_err;
out:
        release_sock(sk);
        return error;
}

static int svc_accept(struct socket *sock, struct socket *newsock,
                      struct proto_accept_arg *arg)
{
        struct sock *sk = sock->sk;
        struct sk_buff *skb;
        struct atmsvc_msg *msg;
        struct atm_vcc *old_vcc = ATM_SD(sock);
        struct atm_vcc *new_vcc;
        int error;

        lock_sock(sk);

        error = svc_create(sock_net(sk), newsock, 0, arg->kern);
        if (error)
                goto out;

        new_vcc = ATM_SD(newsock);

        pr_debug("%p -> %p\n", old_vcc, new_vcc);
        while (1) {
                DEFINE_WAIT(wait);

                prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
                while (!(skb = skb_dequeue(&sk->sk_receive_queue)) &&
                       sigd) {
                        if (test_bit(ATM_VF_RELEASED, &old_vcc->flags))
                                break;
                        if (test_bit(ATM_VF_CLOSE, &old_vcc->flags)) {
                                error = -sk->sk_err;
                                break;
                        }
                        if (arg->flags & O_NONBLOCK) {
                                error = -EAGAIN;
                                break;
                        }
                        release_sock(sk);
                        schedule();
                        lock_sock(sk);
                        if (signal_pending(current)) {
                                error = -ERESTARTSYS;
                                break;
                        }
                        prepare_to_wait(sk_sleep(sk), &wait,
                                        TASK_INTERRUPTIBLE);
                }
                finish_wait(sk_sleep(sk), &wait);
                if (error)
                        goto out;
                if (!skb) {
                        error = -EUNATCH;
                        goto out;
                }
                msg = (struct atmsvc_msg *)skb->data;
                new_vcc->qos = msg->qos;
                set_bit(ATM_VF_HASQOS, &new_vcc->flags);
                new_vcc->remote = msg->svc;
                new_vcc->local = msg->local;
                new_vcc->sap = msg->sap;
                error = vcc_connect(newsock, msg->pvc.sap_addr.itf,
                                    msg->pvc.sap_addr.vpi,
                                    msg->pvc.sap_addr.vci);
                dev_kfree_skb(skb);
                sk_acceptq_removed(sk);
                if (error) {
                        sigd_enq2(NULL, as_reject, old_vcc, NULL, NULL,
                                  &old_vcc->qos, error);
                        error = error == -EAGAIN ? -EBUSY : error;
                        goto out;
                }
                /* wait should be short, so we ignore the non-blocking flag */
                set_bit(ATM_VF_WAITING, &new_vcc->flags);
                sigd_enq(new_vcc, as_accept, old_vcc, NULL, NULL);
                for (;;) {
                        prepare_to_wait(sk_sleep(sk_atm(new_vcc)), &wait,
                                        TASK_UNINTERRUPTIBLE);
                        if (!test_bit(ATM_VF_WAITING, &new_vcc->flags) || !sigd)
                                break;
                        release_sock(sk);
                        schedule();
                        lock_sock(sk);
                }
                finish_wait(sk_sleep(sk_atm(new_vcc)), &wait);
                if (!sigd) {
                        error = -EUNATCH;
                        goto out;
                }
                if (!sk_atm(new_vcc)->sk_err)
                        break;
                if (sk_atm(new_vcc)->sk_err != ERESTARTSYS) {
                        error = -sk_atm(new_vcc)->sk_err;
                        goto out;
                }
        }
        newsock->state = SS_CONNECTED;
out:
        release_sock(sk);
        return error;
}

static int svc_getname(struct socket *sock, struct sockaddr *sockaddr,
                       int peer)
{
        struct sockaddr_atmsvc *addr;

        addr = (struct sockaddr_atmsvc *) sockaddr;
        memcpy(addr, peer ? &ATM_SD(sock)->remote : &ATM_SD(sock)->local,
               sizeof(struct sockaddr_atmsvc));
        return sizeof(struct sockaddr_atmsvc);
}

int svc_change_qos(struct atm_vcc *vcc, struct atm_qos *qos)
{
        struct sock *sk = sk_atm(vcc);
        DEFINE_WAIT(wait);

        set_bit(ATM_VF_WAITING, &vcc->flags);
        sigd_enq2(vcc, as_modify, NULL, NULL, &vcc->local, qos, 0);
        for (;;) {
                prepare_to_wait(sk_sleep(sk), &wait, TASK_UNINTERRUPTIBLE);
                if (!test_bit(ATM_VF_WAITING, &vcc->flags) ||
                    test_bit(ATM_VF_RELEASED, &vcc->flags) || !sigd) {
                        break;
                }
                schedule();
        }
        finish_wait(sk_sleep(sk), &wait);
        if (!sigd)
                return -EUNATCH;
        return -sk->sk_err;
}

static int svc_setsockopt(struct socket *sock, int level, int optname,
                          sockptr_t optval, unsigned int optlen)
{
        struct sock *sk = sock->sk;
        struct atm_vcc *vcc = ATM_SD(sock);
        int value, error = 0;

        lock_sock(sk);
        switch (optname) {
        case SO_ATMSAP:
                if (level != SOL_ATM || optlen != sizeof(struct atm_sap)) {
                        error = -EINVAL;
                        goto out;
                }
                if (copy_from_sockptr(&vcc->sap, optval, optlen)) {
                        error = -EFAULT;
                        goto out;
                }
                set_bit(ATM_VF_HASSAP, &vcc->flags);
                break;
        case SO_MULTIPOINT:
                if (level != SOL_ATM || optlen != sizeof(int)) {
                        error = -EINVAL;
                        goto out;
                }
                if (copy_from_sockptr(&value, optval, sizeof(int))) {
                        error = -EFAULT;
                        goto out;
                }
                if (value == 1)
                        set_bit(ATM_VF_SESSION, &vcc->flags);
                else if (value == 0)
                        clear_bit(ATM_VF_SESSION, &vcc->flags);
                else
                        error = -EINVAL;
                break;
        default:
                error = vcc_setsockopt(sock, level, optname, optval, optlen);
        }

out:
        release_sock(sk);
        return error;
}

static int svc_getsockopt(struct socket *sock, int level, int optname,
                          char __user *optval, int __user *optlen)
{
        struct sock *sk = sock->sk;
        int error = 0, len;

        lock_sock(sk);
        if (!__SO_LEVEL_MATCH(optname, level) || optname != SO_ATMSAP) {
                error = vcc_getsockopt(sock, level, optname, optval, optlen);
                goto out;
        }
        if (get_user(len, optlen)) {
                error = -EFAULT;
                goto out;
        }
        if (len != sizeof(struct atm_sap)) {
                error = -EINVAL;
                goto out;
        }
        if (copy_to_user(optval, &ATM_SD(sock)->sap, sizeof(struct atm_sap))) {
                error = -EFAULT;
                goto out;
        }
out:
        release_sock(sk);
        return error;
}

static int svc_addparty(struct socket *sock, struct sockaddr *sockaddr,
                        int sockaddr_len, int flags)
{
        DEFINE_WAIT(wait);
        struct sock *sk = sock->sk;
        struct atm_vcc *vcc = ATM_SD(sock);
        int error;

        lock_sock(sk);
        set_bit(ATM_VF_WAITING, &vcc->flags);
        sigd_enq(vcc, as_addparty, NULL, NULL,
                 (struct sockaddr_atmsvc *) sockaddr);
        if (flags & O_NONBLOCK) {
                error = -EINPROGRESS;
                goto out;
        }
        pr_debug("added wait queue\n");
        for (;;) {
                prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
                if (!test_bit(ATM_VF_WAITING, &vcc->flags) || !sigd)
                        break;
                schedule();
        }
        finish_wait(sk_sleep(sk), &wait);
        error = -xchg(&sk->sk_err_soft, 0);
out:
        release_sock(sk);
        return error;
}

static int svc_dropparty(struct socket *sock, int ep_ref)
{
        DEFINE_WAIT(wait);
        struct sock *sk = sock->sk;
        struct atm_vcc *vcc = ATM_SD(sock);
        int error;

        lock_sock(sk);
        set_bit(ATM_VF_WAITING, &vcc->flags);
        sigd_enq2(vcc, as_dropparty, NULL, NULL, NULL, NULL, ep_ref);
        for (;;) {
                prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
                if (!test_bit(ATM_VF_WAITING, &vcc->flags) || !sigd)
                        break;
                schedule();
        }
        finish_wait(sk_sleep(sk), &wait);
        if (!sigd) {
                error = -EUNATCH;
                goto out;
        }
        error = -xchg(&sk->sk_err_soft, 0);
out:
        release_sock(sk);
        return error;
}

static int svc_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
        int error, ep_ref;
        struct sockaddr_atmsvc sa;
        struct atm_vcc *vcc = ATM_SD(sock);

        switch (cmd) {
        case ATM_ADDPARTY:
                if (!test_bit(ATM_VF_SESSION, &vcc->flags))
                        return -EINVAL;
                if (copy_from_user(&sa, (void __user *) arg, sizeof(sa)))
                        return -EFAULT;
                error = svc_addparty(sock, (struct sockaddr *)&sa, sizeof(sa),
                                     0);
                break;
        case ATM_DROPPARTY:
                if (!test_bit(ATM_VF_SESSION, &vcc->flags))
                        return -EINVAL;
                if (copy_from_user(&ep_ref, (void __user *) arg, sizeof(int)))
                        return -EFAULT;
                error = svc_dropparty(sock, ep_ref);
                break;
        default:
                error = vcc_ioctl(sock, cmd, arg);
        }

        return error;
}

#ifdef CONFIG_COMPAT
static int svc_compat_ioctl(struct socket *sock, unsigned int cmd,
                            unsigned long arg)
{
        /* The definition of ATM_ADDPARTY uses the size of struct atm_iobuf.
           But actually it takes a struct sockaddr_atmsvc, which doesn't need
           compat handling. So all we have to do is fix up cmd... */
        if (cmd == COMPAT_ATM_ADDPARTY)
                cmd = ATM_ADDPARTY;

        if (cmd == ATM_ADDPARTY || cmd == ATM_DROPPARTY)
                return svc_ioctl(sock, cmd, arg);
        else
                return vcc_compat_ioctl(sock, cmd, arg);
}
#endif /* CONFIG_COMPAT */

static const struct proto_ops svc_proto_ops = {
        .family =       PF_ATMSVC,
        .owner =        THIS_MODULE,

        .release =      svc_release,
        .bind =         svc_bind,
        .connect =      svc_connect,
        .socketpair =   sock_no_socketpair,
        .accept =       svc_accept,
        .getname =      svc_getname,
        .poll =         vcc_poll,
        .ioctl =        svc_ioctl,
#ifdef CONFIG_COMPAT
        .compat_ioctl = svc_compat_ioctl,
#endif
        .gettstamp =    sock_gettstamp,
        .listen =       svc_listen,
        .shutdown =     svc_shutdown,
        .setsockopt =   svc_setsockopt,
        .getsockopt =   svc_getsockopt,
        .sendmsg =      vcc_sendmsg,
        .recvmsg =      vcc_recvmsg,
        .mmap =         sock_no_mmap,
};


static int svc_create(struct net *net, struct socket *sock, int protocol,
                      int kern)
{
        int error;

        if (!net_eq(net, &init_net))
                return -EAFNOSUPPORT;

        sock->ops = &svc_proto_ops;
        error = vcc_create(net, sock, protocol, AF_ATMSVC, kern);
        if (error)
                return error;
        ATM_SD(sock)->local.sas_family = AF_ATMSVC;
        ATM_SD(sock)->remote.sas_family = AF_ATMSVC;
        return 0;
}

static const struct net_proto_family svc_family_ops = {
        .family = PF_ATMSVC,
        .create = svc_create,
        .owner = THIS_MODULE,
};


/*
 *      Initialize the ATM SVC protocol family
 */

int __init atmsvc_init(void)
{
        return sock_register(&svc_family_ops);
}

void atmsvc_exit(void)
{
        sock_unregister(PF_ATMSVC);
}