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
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
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
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
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
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
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
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
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
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