linux/net/atm/signaling.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/* net/atm/signaling.c - ATM signaling */
   3
   4/* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */
   5
   6#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
   7
   8#include <linux/errno.h>        /* error codes */
   9#include <linux/kernel.h>       /* printk */
  10#include <linux/skbuff.h>
  11#include <linux/wait.h>
  12#include <linux/sched.h>        /* jiffies and HZ */
  13#include <linux/atm.h>          /* ATM stuff */
  14#include <linux/atmsap.h>
  15#include <linux/atmsvc.h>
  16#include <linux/atmdev.h>
  17#include <linux/bitops.h>
  18#include <linux/slab.h>
  19
  20#include "resources.h"
  21#include "signaling.h"
  22
  23struct atm_vcc *sigd = NULL;
  24
  25static void sigd_put_skb(struct sk_buff *skb)
  26{
  27        if (!sigd) {
  28                pr_debug("atmsvc: no signaling daemon\n");
  29                kfree_skb(skb);
  30                return;
  31        }
  32        atm_force_charge(sigd, skb->truesize);
  33        skb_queue_tail(&sk_atm(sigd)->sk_receive_queue, skb);
  34        sk_atm(sigd)->sk_data_ready(sk_atm(sigd));
  35}
  36
  37static void modify_qos(struct atm_vcc *vcc, struct atmsvc_msg *msg)
  38{
  39        struct sk_buff *skb;
  40
  41        if (test_bit(ATM_VF_RELEASED, &vcc->flags) ||
  42            !test_bit(ATM_VF_READY, &vcc->flags))
  43                return;
  44        msg->type = as_error;
  45        if (!vcc->dev->ops->change_qos)
  46                msg->reply = -EOPNOTSUPP;
  47        else {
  48                /* should lock VCC */
  49                msg->reply = vcc->dev->ops->change_qos(vcc, &msg->qos,
  50                                                       msg->reply);
  51                if (!msg->reply)
  52                        msg->type = as_okay;
  53        }
  54        /*
  55         * Should probably just turn around the old skb. But then, the buffer
  56         * space accounting needs to follow the change too. Maybe later.
  57         */
  58        while (!(skb = alloc_skb(sizeof(struct atmsvc_msg), GFP_KERNEL)))
  59                schedule();
  60        *(struct atmsvc_msg *)skb_put(skb, sizeof(struct atmsvc_msg)) = *msg;
  61        sigd_put_skb(skb);
  62}
  63
  64static int sigd_send(struct atm_vcc *vcc, struct sk_buff *skb)
  65{
  66        struct atmsvc_msg *msg;
  67        struct atm_vcc *session_vcc;
  68        struct sock *sk;
  69
  70        msg = (struct atmsvc_msg *) skb->data;
  71        WARN_ON(refcount_sub_and_test(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc));
  72        vcc = *(struct atm_vcc **) &msg->vcc;
  73        pr_debug("%d (0x%lx)\n", (int)msg->type, (unsigned long)vcc);
  74        sk = sk_atm(vcc);
  75
  76        switch (msg->type) {
  77        case as_okay:
  78                sk->sk_err = -msg->reply;
  79                clear_bit(ATM_VF_WAITING, &vcc->flags);
  80                if (!*vcc->local.sas_addr.prv && !*vcc->local.sas_addr.pub) {
  81                        vcc->local.sas_family = AF_ATMSVC;
  82                        memcpy(vcc->local.sas_addr.prv,
  83                               msg->local.sas_addr.prv, ATM_ESA_LEN);
  84                        memcpy(vcc->local.sas_addr.pub,
  85                               msg->local.sas_addr.pub, ATM_E164_LEN + 1);
  86                }
  87                session_vcc = vcc->session ? vcc->session : vcc;
  88                if (session_vcc->vpi || session_vcc->vci)
  89                        break;
  90                session_vcc->itf = msg->pvc.sap_addr.itf;
  91                session_vcc->vpi = msg->pvc.sap_addr.vpi;
  92                session_vcc->vci = msg->pvc.sap_addr.vci;
  93                if (session_vcc->vpi || session_vcc->vci)
  94                        session_vcc->qos = msg->qos;
  95                break;
  96        case as_error:
  97                clear_bit(ATM_VF_REGIS, &vcc->flags);
  98                clear_bit(ATM_VF_READY, &vcc->flags);
  99                sk->sk_err = -msg->reply;
 100                clear_bit(ATM_VF_WAITING, &vcc->flags);
 101                break;
 102        case as_indicate:
 103                vcc = *(struct atm_vcc **)&msg->listen_vcc;
 104                sk = sk_atm(vcc);
 105                pr_debug("as_indicate!!!\n");
 106                lock_sock(sk);
 107                if (sk_acceptq_is_full(sk)) {
 108                        sigd_enq(NULL, as_reject, vcc, NULL, NULL);
 109                        dev_kfree_skb(skb);
 110                        goto as_indicate_complete;
 111                }
 112                sk_acceptq_added(sk);
 113                skb_queue_tail(&sk->sk_receive_queue, skb);
 114                pr_debug("waking sk_sleep(sk) 0x%p\n", sk_sleep(sk));
 115                sk->sk_state_change(sk);
 116as_indicate_complete:
 117                release_sock(sk);
 118                return 0;
 119        case as_close:
 120                set_bit(ATM_VF_RELEASED, &vcc->flags);
 121                vcc_release_async(vcc, msg->reply);
 122                goto out;
 123        case as_modify:
 124                modify_qos(vcc, msg);
 125                break;
 126        case as_addparty:
 127        case as_dropparty:
 128                sk->sk_err_soft = -msg->reply;
 129                                        /* < 0 failure, otherwise ep_ref */
 130                clear_bit(ATM_VF_WAITING, &vcc->flags);
 131                break;
 132        default:
 133                pr_alert("bad message type %d\n", (int)msg->type);
 134                return -EINVAL;
 135        }
 136        sk->sk_state_change(sk);
 137out:
 138        dev_kfree_skb(skb);
 139        return 0;
 140}
 141
 142void sigd_enq2(struct atm_vcc *vcc, enum atmsvc_msg_type type,
 143               struct atm_vcc *listen_vcc, const struct sockaddr_atmpvc *pvc,
 144               const struct sockaddr_atmsvc *svc, const struct atm_qos *qos,
 145               int reply)
 146{
 147        struct sk_buff *skb;
 148        struct atmsvc_msg *msg;
 149        static unsigned int session = 0;
 150
 151        pr_debug("%d (0x%p)\n", (int)type, vcc);
 152        while (!(skb = alloc_skb(sizeof(struct atmsvc_msg), GFP_KERNEL)))
 153                schedule();
 154        msg = skb_put_zero(skb, sizeof(struct atmsvc_msg));
 155        msg->type = type;
 156        *(struct atm_vcc **) &msg->vcc = vcc;
 157        *(struct atm_vcc **) &msg->listen_vcc = listen_vcc;
 158        msg->reply = reply;
 159        if (qos)
 160                msg->qos = *qos;
 161        if (vcc)
 162                msg->sap = vcc->sap;
 163        if (svc)
 164                msg->svc = *svc;
 165        if (vcc)
 166                msg->local = vcc->local;
 167        if (pvc)
 168                msg->pvc = *pvc;
 169        if (vcc) {
 170                if (type == as_connect && test_bit(ATM_VF_SESSION, &vcc->flags))
 171                        msg->session = ++session;
 172                        /* every new pmp connect gets the next session number */
 173        }
 174        sigd_put_skb(skb);
 175        if (vcc)
 176                set_bit(ATM_VF_REGIS, &vcc->flags);
 177}
 178
 179void sigd_enq(struct atm_vcc *vcc, enum atmsvc_msg_type type,
 180              struct atm_vcc *listen_vcc, const struct sockaddr_atmpvc *pvc,
 181              const struct sockaddr_atmsvc *svc)
 182{
 183        sigd_enq2(vcc, type, listen_vcc, pvc, svc, vcc ? &vcc->qos : NULL, 0);
 184        /* other ISP applications may use "reply" */
 185}
 186
 187static void purge_vcc(struct atm_vcc *vcc)
 188{
 189        if (sk_atm(vcc)->sk_family == PF_ATMSVC &&
 190            !test_bit(ATM_VF_META, &vcc->flags)) {
 191                set_bit(ATM_VF_RELEASED, &vcc->flags);
 192                clear_bit(ATM_VF_REGIS, &vcc->flags);
 193                vcc_release_async(vcc, -EUNATCH);
 194        }
 195}
 196
 197static void sigd_close(struct atm_vcc *vcc)
 198{
 199        struct sock *s;
 200        int i;
 201
 202        pr_debug("\n");
 203        sigd = NULL;
 204        if (skb_peek(&sk_atm(vcc)->sk_receive_queue))
 205                pr_err("closing with requests pending\n");
 206        skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
 207
 208        read_lock(&vcc_sklist_lock);
 209        for (i = 0; i < VCC_HTABLE_SIZE; ++i) {
 210                struct hlist_head *head = &vcc_hash[i];
 211
 212                sk_for_each(s, head) {
 213                        vcc = atm_sk(s);
 214
 215                        purge_vcc(vcc);
 216                }
 217        }
 218        read_unlock(&vcc_sklist_lock);
 219}
 220
 221static const struct atmdev_ops sigd_dev_ops = {
 222        .close = sigd_close,
 223        .send = sigd_send
 224};
 225
 226static struct atm_dev sigd_dev = {
 227        .ops =          &sigd_dev_ops,
 228        .type =         "sig",
 229        .number =       999,
 230        .lock =         __SPIN_LOCK_UNLOCKED(sigd_dev.lock)
 231};
 232
 233int sigd_attach(struct atm_vcc *vcc)
 234{
 235        if (sigd)
 236                return -EADDRINUSE;
 237        pr_debug("\n");
 238        sigd = vcc;
 239        vcc->dev = &sigd_dev;
 240        vcc_insert_socket(sk_atm(vcc));
 241        set_bit(ATM_VF_META, &vcc->flags);
 242        set_bit(ATM_VF_READY, &vcc->flags);
 243        return 0;
 244}
 245
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