linux/net/atm/signaling.c
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   1/* net/atm/signaling.c - ATM signaling */
   2
   3/* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */
   4
   5#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
   6
   7#include <linux/errno.h>        /* error codes */
   8#include <linux/kernel.h>       /* printk */
   9#include <linux/skbuff.h>
  10#include <linux/wait.h>
  11#include <linux/sched.h>        /* jiffies and HZ */
  12#include <linux/atm.h>          /* ATM stuff */
  13#include <linux/atmsap.h>
  14#include <linux/atmsvc.h>
  15#include <linux/atmdev.h>
  16#include <linux/bitops.h>
  17#include <linux/slab.h>
  18
  19#include "resources.h"
  20#include "signaling.h"
  21
  22#undef WAIT_FOR_DEMON           /* #define this if system calls on SVC sockets
  23                                   should block until the demon runs.
  24                                   Danger: may cause nasty hangs if the demon
  25                                   crashes. */
  26
  27struct atm_vcc *sigd = NULL;
  28#ifdef WAIT_FOR_DEMON
  29static DECLARE_WAIT_QUEUE_HEAD(sigd_sleep);
  30#endif
  31
  32static void sigd_put_skb(struct sk_buff *skb)
  33{
  34#ifdef WAIT_FOR_DEMON
  35        DECLARE_WAITQUEUE(wait, current);
  36
  37        add_wait_queue(&sigd_sleep, &wait);
  38        while (!sigd) {
  39                set_current_state(TASK_UNINTERRUPTIBLE);
  40                pr_debug("atmsvc: waiting for signaling daemon...\n");
  41                schedule();
  42        }
  43        current->state = TASK_RUNNING;
  44        remove_wait_queue(&sigd_sleep, &wait);
  45#else
  46        if (!sigd) {
  47                pr_debug("atmsvc: no signaling daemon\n");
  48                kfree_skb(skb);
  49                return;
  50        }
  51#endif
  52        atm_force_charge(sigd, skb->truesize);
  53        skb_queue_tail(&sk_atm(sigd)->sk_receive_queue, skb);
  54        sk_atm(sigd)->sk_data_ready(sk_atm(sigd), skb->len);
  55}
  56
  57static void modify_qos(struct atm_vcc *vcc, struct atmsvc_msg *msg)
  58{
  59        struct sk_buff *skb;
  60
  61        if (test_bit(ATM_VF_RELEASED, &vcc->flags) ||
  62            !test_bit(ATM_VF_READY, &vcc->flags))
  63                return;
  64        msg->type = as_error;
  65        if (!vcc->dev->ops->change_qos)
  66                msg->reply = -EOPNOTSUPP;
  67        else {
  68                /* should lock VCC */
  69                msg->reply = vcc->dev->ops->change_qos(vcc, &msg->qos,
  70                                                       msg->reply);
  71                if (!msg->reply)
  72                        msg->type = as_okay;
  73        }
  74        /*
  75         * Should probably just turn around the old skb. But the, the buffer
  76         * space accounting needs to follow the change too. Maybe later.
  77         */
  78        while (!(skb = alloc_skb(sizeof(struct atmsvc_msg), GFP_KERNEL)))
  79                schedule();
  80        *(struct atmsvc_msg *)skb_put(skb, sizeof(struct atmsvc_msg)) = *msg;
  81        sigd_put_skb(skb);
  82}
  83
  84static int sigd_send(struct atm_vcc *vcc, struct sk_buff *skb)
  85{
  86        struct atmsvc_msg *msg;
  87        struct atm_vcc *session_vcc;
  88        struct sock *sk;
  89
  90        msg = (struct atmsvc_msg *) skb->data;
  91        atomic_sub(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
  92        vcc = *(struct atm_vcc **) &msg->vcc;
  93        pr_debug("%d (0x%lx)\n", (int)msg->type, (unsigned long)vcc);
  94        sk = sk_atm(vcc);
  95
  96        switch (msg->type) {
  97        case as_okay:
  98                sk->sk_err = -msg->reply;
  99                clear_bit(ATM_VF_WAITING, &vcc->flags);
 100                if (!*vcc->local.sas_addr.prv && !*vcc->local.sas_addr.pub) {
 101                        vcc->local.sas_family = AF_ATMSVC;
 102                        memcpy(vcc->local.sas_addr.prv,
 103                               msg->local.sas_addr.prv, ATM_ESA_LEN);
 104                        memcpy(vcc->local.sas_addr.pub,
 105                               msg->local.sas_addr.pub, ATM_E164_LEN + 1);
 106                }
 107                session_vcc = vcc->session ? vcc->session : vcc;
 108                if (session_vcc->vpi || session_vcc->vci)
 109                        break;
 110                session_vcc->itf = msg->pvc.sap_addr.itf;
 111                session_vcc->vpi = msg->pvc.sap_addr.vpi;
 112                session_vcc->vci = msg->pvc.sap_addr.vci;
 113                if (session_vcc->vpi || session_vcc->vci)
 114                        session_vcc->qos = msg->qos;
 115                break;
 116        case as_error:
 117                clear_bit(ATM_VF_REGIS, &vcc->flags);
 118                clear_bit(ATM_VF_READY, &vcc->flags);
 119                sk->sk_err = -msg->reply;
 120                clear_bit(ATM_VF_WAITING, &vcc->flags);
 121                break;
 122        case as_indicate:
 123                vcc = *(struct atm_vcc **)&msg->listen_vcc;
 124                sk = sk_atm(vcc);
 125                pr_debug("as_indicate!!!\n");
 126                lock_sock(sk);
 127                if (sk_acceptq_is_full(sk)) {
 128                        sigd_enq(NULL, as_reject, vcc, NULL, NULL);
 129                        dev_kfree_skb(skb);
 130                        goto as_indicate_complete;
 131                }
 132                sk->sk_ack_backlog++;
 133                skb_queue_tail(&sk->sk_receive_queue, skb);
 134                pr_debug("waking sk_sleep(sk) 0x%p\n", sk_sleep(sk));
 135                sk->sk_state_change(sk);
 136as_indicate_complete:
 137                release_sock(sk);
 138                return 0;
 139        case as_close:
 140                set_bit(ATM_VF_RELEASED, &vcc->flags);
 141                vcc_release_async(vcc, msg->reply);
 142                goto out;
 143        case as_modify:
 144                modify_qos(vcc, msg);
 145                break;
 146        case as_addparty:
 147        case as_dropparty:
 148                sk->sk_err_soft = msg->reply;
 149                                        /* < 0 failure, otherwise ep_ref */
 150                clear_bit(ATM_VF_WAITING, &vcc->flags);
 151                break;
 152        default:
 153                pr_alert("bad message type %d\n", (int)msg->type);
 154                return -EINVAL;
 155        }
 156        sk->sk_state_change(sk);
 157out:
 158        dev_kfree_skb(skb);
 159        return 0;
 160}
 161
 162void sigd_enq2(struct atm_vcc *vcc, enum atmsvc_msg_type type,
 163               struct atm_vcc *listen_vcc, const struct sockaddr_atmpvc *pvc,
 164               const struct sockaddr_atmsvc *svc, const struct atm_qos *qos,
 165               int reply)
 166{
 167        struct sk_buff *skb;
 168        struct atmsvc_msg *msg;
 169        static unsigned int session = 0;
 170
 171        pr_debug("%d (0x%p)\n", (int)type, vcc);
 172        while (!(skb = alloc_skb(sizeof(struct atmsvc_msg), GFP_KERNEL)))
 173                schedule();
 174        msg = (struct atmsvc_msg *)skb_put(skb, sizeof(struct atmsvc_msg));
 175        memset(msg, 0, sizeof(*msg));
 176        msg->type = type;
 177        *(struct atm_vcc **) &msg->vcc = vcc;
 178        *(struct atm_vcc **) &msg->listen_vcc = listen_vcc;
 179        msg->reply = reply;
 180        if (qos)
 181                msg->qos = *qos;
 182        if (vcc)
 183                msg->sap = vcc->sap;
 184        if (svc)
 185                msg->svc = *svc;
 186        if (vcc)
 187                msg->local = vcc->local;
 188        if (pvc)
 189                msg->pvc = *pvc;
 190        if (vcc) {
 191                if (type == as_connect && test_bit(ATM_VF_SESSION, &vcc->flags))
 192                        msg->session = ++session;
 193                        /* every new pmp connect gets the next session number */
 194        }
 195        sigd_put_skb(skb);
 196        if (vcc)
 197                set_bit(ATM_VF_REGIS, &vcc->flags);
 198}
 199
 200void sigd_enq(struct atm_vcc *vcc, enum atmsvc_msg_type type,
 201              struct atm_vcc *listen_vcc, const struct sockaddr_atmpvc *pvc,
 202              const struct sockaddr_atmsvc *svc)
 203{
 204        sigd_enq2(vcc, type, listen_vcc, pvc, svc, vcc ? &vcc->qos : NULL, 0);
 205        /* other ISP applications may use "reply" */
 206}
 207
 208static void purge_vcc(struct atm_vcc *vcc)
 209{
 210        if (sk_atm(vcc)->sk_family == PF_ATMSVC &&
 211            !test_bit(ATM_VF_META, &vcc->flags)) {
 212                set_bit(ATM_VF_RELEASED, &vcc->flags);
 213                clear_bit(ATM_VF_REGIS, &vcc->flags);
 214                vcc_release_async(vcc, -EUNATCH);
 215        }
 216}
 217
 218static void sigd_close(struct atm_vcc *vcc)
 219{
 220        struct hlist_node *node;
 221        struct sock *s;
 222        int i;
 223
 224        pr_debug("\n");
 225        sigd = NULL;
 226        if (skb_peek(&sk_atm(vcc)->sk_receive_queue))
 227                pr_err("closing with requests pending\n");
 228        skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
 229
 230        read_lock(&vcc_sklist_lock);
 231        for (i = 0; i < VCC_HTABLE_SIZE; ++i) {
 232                struct hlist_head *head = &vcc_hash[i];
 233
 234                sk_for_each(s, node, head) {
 235                        vcc = atm_sk(s);
 236
 237                        purge_vcc(vcc);
 238                }
 239        }
 240        read_unlock(&vcc_sklist_lock);
 241}
 242
 243static struct atmdev_ops sigd_dev_ops = {
 244        .close = sigd_close,
 245        .send = sigd_send
 246};
 247
 248static struct atm_dev sigd_dev = {
 249        .ops =          &sigd_dev_ops,
 250        .type =         "sig",
 251        .number =       999,
 252        .lock =         __SPIN_LOCK_UNLOCKED(sigd_dev.lock)
 253};
 254
 255int sigd_attach(struct atm_vcc *vcc)
 256{
 257        if (sigd)
 258                return -EADDRINUSE;
 259        pr_debug("\n");
 260        sigd = vcc;
 261        vcc->dev = &sigd_dev;
 262        vcc_insert_socket(sk_atm(vcc));
 263        set_bit(ATM_VF_META, &vcc->flags);
 264        set_bit(ATM_VF_READY, &vcc->flags);
 265#ifdef WAIT_FOR_DEMON
 266        wake_up(&sigd_sleep);
 267#endif
 268        return 0;
 269}
 270
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