xref: /openbmc/linux/net/atm/signaling.c (revision 1ac731c529cd4d6adbce134754b51ff7d822b145)
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  
23  struct atm_vcc *sigd = NULL;
24  
sigd_put_skb(struct sk_buff * skb)25  static 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  
modify_qos(struct atm_vcc * vcc,struct atmsvc_msg * msg)37  static 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  
sigd_send(struct atm_vcc * vcc,struct sk_buff * skb)64  static 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);
116  as_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  		WRITE_ONCE(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);
137  out:
138  	dev_kfree_skb(skb);
139  	return 0;
140  }
141  
sigd_enq2(struct atm_vcc * vcc,enum atmsvc_msg_type type,struct atm_vcc * listen_vcc,const struct sockaddr_atmpvc * pvc,const struct sockaddr_atmsvc * svc,const struct atm_qos * qos,int reply)142  void 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  
sigd_enq(struct atm_vcc * vcc,enum atmsvc_msg_type type,struct atm_vcc * listen_vcc,const struct sockaddr_atmpvc * pvc,const struct sockaddr_atmsvc * svc)179  void 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  
purge_vcc(struct atm_vcc * vcc)187  static 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  
sigd_close(struct atm_vcc * vcc)197  static 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  
221  static const struct atmdev_ops sigd_dev_ops = {
222  	.close = sigd_close,
223  	.send =	sigd_send
224  };
225  
226  static 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  
sigd_attach(struct atm_vcc * vcc)233  int 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