net/atm/signaling.c

   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
  27 struct atm_vcc *sigd = NULL;
  28 #ifdef WAIT_FOR_DEMON
  29 static DECLARE_WAIT_QUEUE_HEAD(sigd_sleep);
  30 #endif
  31
  32 static 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));
  55 }
  56
  57 static 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
  84 static 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);
 136 as_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);
 157 out:
 158         dev_kfree_skb(skb);
 159         return 0;
 160 }
 161
 162 void 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
 200 void 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
 208 static 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
 218 static void sigd_close(struct atm_vcc *vcc)
 219 {
 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, 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 }