xref: /openbmc/linux/net/atm/signaling.c (revision 2f2d9972)
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