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 /*
26 * find_get_vcc - validate and get a reference to a vcc pointer
27 * @vcc: the vcc pointer to validate
28 *
29 * This function validates that @vcc points to a registered VCC in vcc_hash.
30 * If found, it increments the socket reference count and returns the vcc.
31 * The caller must call sock_put(sk_atm(vcc)) when done.
32 *
33 * Returns the vcc pointer if valid, NULL otherwise.
34 */
find_get_vcc(struct atm_vcc * vcc)35 static struct atm_vcc *find_get_vcc(struct atm_vcc *vcc)
36 {
37 int i;
38
39 read_lock(&vcc_sklist_lock);
40 for (i = 0; i < VCC_HTABLE_SIZE; i++) {
41 struct sock *s;
42
43 sk_for_each(s, &vcc_hash[i]) {
44 if (atm_sk(s) == vcc) {
45 sock_hold(s);
46 read_unlock(&vcc_sklist_lock);
47 return vcc;
48 }
49 }
50 }
51 read_unlock(&vcc_sklist_lock);
52 return NULL;
53 }
54
sigd_put_skb(struct sk_buff * skb)55 static void sigd_put_skb(struct sk_buff *skb)
56 {
57 if (!sigd) {
58 pr_debug("atmsvc: no signaling daemon\n");
59 kfree_skb(skb);
60 return;
61 }
62 atm_force_charge(sigd, skb->truesize);
63 skb_queue_tail(&sk_atm(sigd)->sk_receive_queue, skb);
64 sk_atm(sigd)->sk_data_ready(sk_atm(sigd));
65 }
66
modify_qos(struct atm_vcc * vcc,struct atmsvc_msg * msg)67 static void modify_qos(struct atm_vcc *vcc, struct atmsvc_msg *msg)
68 {
69 struct sk_buff *skb;
70
71 if (test_bit(ATM_VF_RELEASED, &vcc->flags) ||
72 !test_bit(ATM_VF_READY, &vcc->flags))
73 return;
74 msg->type = as_error;
75 if (!vcc->dev->ops->change_qos)
76 msg->reply = -EOPNOTSUPP;
77 else {
78 /* should lock VCC */
79 msg->reply = vcc->dev->ops->change_qos(vcc, &msg->qos,
80 msg->reply);
81 if (!msg->reply)
82 msg->type = as_okay;
83 }
84 /*
85 * Should probably just turn around the old skb. But then, the buffer
86 * space accounting needs to follow the change too. Maybe later.
87 */
88 while (!(skb = alloc_skb(sizeof(struct atmsvc_msg), GFP_KERNEL)))
89 schedule();
90 *(struct atmsvc_msg *)skb_put(skb, sizeof(struct atmsvc_msg)) = *msg;
91 sigd_put_skb(skb);
92 }
93
sigd_send(struct atm_vcc * vcc,struct sk_buff * skb)94 static int sigd_send(struct atm_vcc *vcc, struct sk_buff *skb)
95 {
96 struct atmsvc_msg *msg;
97 struct atm_vcc *session_vcc;
98 struct sock *sk;
99
100 msg = (struct atmsvc_msg *) skb->data;
101 WARN_ON(refcount_sub_and_test(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc));
102
103 vcc = find_get_vcc(*(struct atm_vcc **)&msg->vcc);
104 if (!vcc) {
105 pr_debug("invalid vcc pointer in msg\n");
106 dev_kfree_skb(skb);
107 return -EINVAL;
108 }
109
110 pr_debug("%d (0x%lx)\n", (int)msg->type, (unsigned long)vcc);
111 sk = sk_atm(vcc);
112
113 switch (msg->type) {
114 case as_okay:
115 sk->sk_err = -msg->reply;
116 clear_bit(ATM_VF_WAITING, &vcc->flags);
117 if (!*vcc->local.sas_addr.prv && !*vcc->local.sas_addr.pub) {
118 vcc->local.sas_family = AF_ATMSVC;
119 memcpy(vcc->local.sas_addr.prv,
120 msg->local.sas_addr.prv, ATM_ESA_LEN);
121 memcpy(vcc->local.sas_addr.pub,
122 msg->local.sas_addr.pub, ATM_E164_LEN + 1);
123 }
124 session_vcc = vcc->session ? vcc->session : vcc;
125 if (session_vcc->vpi || session_vcc->vci)
126 break;
127 session_vcc->itf = msg->pvc.sap_addr.itf;
128 session_vcc->vpi = msg->pvc.sap_addr.vpi;
129 session_vcc->vci = msg->pvc.sap_addr.vci;
130 if (session_vcc->vpi || session_vcc->vci)
131 session_vcc->qos = msg->qos;
132 break;
133 case as_error:
134 clear_bit(ATM_VF_REGIS, &vcc->flags);
135 clear_bit(ATM_VF_READY, &vcc->flags);
136 sk->sk_err = -msg->reply;
137 clear_bit(ATM_VF_WAITING, &vcc->flags);
138 break;
139 case as_indicate:
140 /* Release the reference from msg->vcc, we'll use msg->listen_vcc instead */
141 sock_put(sk);
142
143 vcc = find_get_vcc(*(struct atm_vcc **)&msg->listen_vcc);
144 if (!vcc) {
145 pr_debug("invalid listen_vcc pointer in msg\n");
146 dev_kfree_skb(skb);
147 return -EINVAL;
148 }
149
150 sk = sk_atm(vcc);
151 pr_debug("as_indicate!!!\n");
152 lock_sock(sk);
153 if (sk_acceptq_is_full(sk)) {
154 sigd_enq(NULL, as_reject, vcc, NULL, NULL);
155 dev_kfree_skb(skb);
156 goto as_indicate_complete;
157 }
158 sk_acceptq_added(sk);
159 skb_queue_tail(&sk->sk_receive_queue, skb);
160 pr_debug("waking sk_sleep(sk) 0x%p\n", sk_sleep(sk));
161 sk->sk_state_change(sk);
162 as_indicate_complete:
163 release_sock(sk);
164 /* Paired with find_get_vcc(msg->listen_vcc) above */
165 sock_put(sk);
166 return 0;
167 case as_close:
168 set_bit(ATM_VF_RELEASED, &vcc->flags);
169 vcc_release_async(vcc, msg->reply);
170 goto out;
171 case as_modify:
172 modify_qos(vcc, msg);
173 break;
174 case as_addparty:
175 case as_dropparty:
176 WRITE_ONCE(sk->sk_err_soft, -msg->reply);
177 /* < 0 failure, otherwise ep_ref */
178 clear_bit(ATM_VF_WAITING, &vcc->flags);
179 break;
180 default:
181 pr_alert("bad message type %d\n", (int)msg->type);
182 /* Paired with find_get_vcc(msg->vcc) above */
183 sock_put(sk);
184 return -EINVAL;
185 }
186 sk->sk_state_change(sk);
187 out:
188 dev_kfree_skb(skb);
189 /* Paired with find_get_vcc(msg->vcc) above */
190 sock_put(sk);
191 return 0;
192 }
193
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)194 void sigd_enq2(struct atm_vcc *vcc, enum atmsvc_msg_type type,
195 struct atm_vcc *listen_vcc, const struct sockaddr_atmpvc *pvc,
196 const struct sockaddr_atmsvc *svc, const struct atm_qos *qos,
197 int reply)
198 {
199 struct sk_buff *skb;
200 struct atmsvc_msg *msg;
201 static unsigned int session = 0;
202
203 pr_debug("%d (0x%p)\n", (int)type, vcc);
204 while (!(skb = alloc_skb(sizeof(struct atmsvc_msg), GFP_KERNEL)))
205 schedule();
206 msg = skb_put_zero(skb, sizeof(struct atmsvc_msg));
207 msg->type = type;
208 *(struct atm_vcc **) &msg->vcc = vcc;
209 *(struct atm_vcc **) &msg->listen_vcc = listen_vcc;
210 msg->reply = reply;
211 if (qos)
212 msg->qos = *qos;
213 if (vcc)
214 msg->sap = vcc->sap;
215 if (svc)
216 msg->svc = *svc;
217 if (vcc)
218 msg->local = vcc->local;
219 if (pvc)
220 msg->pvc = *pvc;
221 if (vcc) {
222 if (type == as_connect && test_bit(ATM_VF_SESSION, &vcc->flags))
223 msg->session = ++session;
224 /* every new pmp connect gets the next session number */
225 }
226 sigd_put_skb(skb);
227 if (vcc)
228 set_bit(ATM_VF_REGIS, &vcc->flags);
229 }
230
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)231 void sigd_enq(struct atm_vcc *vcc, enum atmsvc_msg_type type,
232 struct atm_vcc *listen_vcc, const struct sockaddr_atmpvc *pvc,
233 const struct sockaddr_atmsvc *svc)
234 {
235 sigd_enq2(vcc, type, listen_vcc, pvc, svc, vcc ? &vcc->qos : NULL, 0);
236 /* other ISP applications may use "reply" */
237 }
238
purge_vcc(struct atm_vcc * vcc)239 static void purge_vcc(struct atm_vcc *vcc)
240 {
241 if (sk_atm(vcc)->sk_family == PF_ATMSVC &&
242 !test_bit(ATM_VF_META, &vcc->flags)) {
243 set_bit(ATM_VF_RELEASED, &vcc->flags);
244 clear_bit(ATM_VF_REGIS, &vcc->flags);
245 vcc_release_async(vcc, -EUNATCH);
246 }
247 }
248
sigd_close(struct atm_vcc * vcc)249 static void sigd_close(struct atm_vcc *vcc)
250 {
251 struct sock *s;
252 int i;
253
254 pr_debug("\n");
255 sigd = NULL;
256 if (skb_peek(&sk_atm(vcc)->sk_receive_queue))
257 pr_err("closing with requests pending\n");
258 skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
259
260 read_lock(&vcc_sklist_lock);
261 for (i = 0; i < VCC_HTABLE_SIZE; ++i) {
262 struct hlist_head *head = &vcc_hash[i];
263
264 sk_for_each(s, head) {
265 vcc = atm_sk(s);
266
267 purge_vcc(vcc);
268 }
269 }
270 read_unlock(&vcc_sklist_lock);
271 }
272
273 static const struct atmdev_ops sigd_dev_ops = {
274 .close = sigd_close,
275 .send = sigd_send
276 };
277
278 static struct atm_dev sigd_dev = {
279 .ops = &sigd_dev_ops,
280 .type = "sig",
281 .number = 999,
282 .lock = __SPIN_LOCK_UNLOCKED(sigd_dev.lock)
283 };
284
sigd_attach(struct atm_vcc * vcc)285 int sigd_attach(struct atm_vcc *vcc)
286 {
287 if (sigd)
288 return -EADDRINUSE;
289 pr_debug("\n");
290 sigd = vcc;
291 vcc->dev = &sigd_dev;
292 vcc_insert_socket(sk_atm(vcc));
293 set_bit(ATM_VF_META, &vcc->flags);
294 set_bit(ATM_VF_READY, &vcc->flags);
295 return 0;
296 }
297