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