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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 | 2 | /* |
1da177e4 LT |
3 | * |
4 | * Copyright Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) | |
5 | */ | |
6 | #include <linux/errno.h> | |
7 | #include <linux/types.h> | |
8 | #include <linux/socket.h> | |
9 | #include <linux/in.h> | |
10 | #include <linux/kernel.h> | |
1da177e4 LT |
11 | #include <linux/timer.h> |
12 | #include <linux/string.h> | |
13 | #include <linux/sockios.h> | |
14 | #include <linux/net.h> | |
5a0e3ad6 | 15 | #include <linux/slab.h> |
1da177e4 LT |
16 | #include <net/ax25.h> |
17 | #include <linux/inet.h> | |
18 | #include <linux/netdevice.h> | |
19 | #include <linux/skbuff.h> | |
20 | #include <net/sock.h> | |
c752f073 | 21 | #include <net/tcp_states.h> |
dc8e5416 | 22 | #include <linux/uaccess.h> |
1da177e4 LT |
23 | #include <linux/fcntl.h> |
24 | #include <linux/mm.h> | |
25 | #include <linux/interrupt.h> | |
26 | #include <net/netrom.h> | |
27 | ||
28 | /* | |
29 | * This routine purges all of the queues of frames. | |
30 | */ | |
31 | void nr_clear_queues(struct sock *sk) | |
32 | { | |
33 | struct nr_sock *nr = nr_sk(sk); | |
34 | ||
35 | skb_queue_purge(&sk->sk_write_queue); | |
36 | skb_queue_purge(&nr->ack_queue); | |
37 | skb_queue_purge(&nr->reseq_queue); | |
38 | skb_queue_purge(&nr->frag_queue); | |
39 | } | |
40 | ||
41 | /* | |
42 | * This routine purges the input queue of those frames that have been | |
43 | * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the | |
44 | * SDL diagram. | |
45 | */ | |
46 | void nr_frames_acked(struct sock *sk, unsigned short nr) | |
47 | { | |
48 | struct nr_sock *nrom = nr_sk(sk); | |
49 | struct sk_buff *skb; | |
50 | ||
51 | /* | |
52 | * Remove all the ack-ed frames from the ack queue. | |
53 | */ | |
54 | if (nrom->va != nr) { | |
55 | while (skb_peek(&nrom->ack_queue) != NULL && nrom->va != nr) { | |
5f8f59d6 | 56 | skb = skb_dequeue(&nrom->ack_queue); |
1da177e4 LT |
57 | kfree_skb(skb); |
58 | nrom->va = (nrom->va + 1) % NR_MODULUS; | |
59 | } | |
60 | } | |
61 | } | |
62 | ||
63 | /* | |
64 | * Requeue all the un-ack-ed frames on the output queue to be picked | |
65 | * up by nr_kick called from the timer. This arrangement handles the | |
66 | * possibility of an empty output queue. | |
67 | */ | |
68 | void nr_requeue_frames(struct sock *sk) | |
69 | { | |
70 | struct sk_buff *skb, *skb_prev = NULL; | |
71 | ||
72 | while ((skb = skb_dequeue(&nr_sk(sk)->ack_queue)) != NULL) { | |
73 | if (skb_prev == NULL) | |
74 | skb_queue_head(&sk->sk_write_queue, skb); | |
75 | else | |
8728b834 | 76 | skb_append(skb_prev, skb, &sk->sk_write_queue); |
1da177e4 LT |
77 | skb_prev = skb; |
78 | } | |
79 | } | |
80 | ||
81 | /* | |
82 | * Validate that the value of nr is between va and vs. Return true or | |
83 | * false for testing. | |
84 | */ | |
85 | int nr_validate_nr(struct sock *sk, unsigned short nr) | |
86 | { | |
87 | struct nr_sock *nrom = nr_sk(sk); | |
88 | unsigned short vc = nrom->va; | |
89 | ||
90 | while (vc != nrom->vs) { | |
91 | if (nr == vc) return 1; | |
92 | vc = (vc + 1) % NR_MODULUS; | |
93 | } | |
94 | ||
95 | return nr == nrom->vs; | |
96 | } | |
97 | ||
98 | /* | |
99 | * Check that ns is within the receive window. | |
100 | */ | |
101 | int nr_in_rx_window(struct sock *sk, unsigned short ns) | |
102 | { | |
103 | struct nr_sock *nr = nr_sk(sk); | |
104 | unsigned short vc = nr->vr; | |
105 | unsigned short vt = (nr->vl + nr->window) % NR_MODULUS; | |
106 | ||
107 | while (vc != vt) { | |
108 | if (ns == vc) return 1; | |
109 | vc = (vc + 1) % NR_MODULUS; | |
110 | } | |
111 | ||
112 | return 0; | |
113 | } | |
114 | ||
115 | /* | |
116 | * This routine is called when the HDLC layer internally generates a | |
117 | * control frame. | |
118 | */ | |
119 | void nr_write_internal(struct sock *sk, int frametype) | |
120 | { | |
121 | struct nr_sock *nr = nr_sk(sk); | |
122 | struct sk_buff *skb; | |
123 | unsigned char *dptr; | |
124 | int len, timeout; | |
125 | ||
126 | len = NR_NETWORK_LEN + NR_TRANSPORT_LEN; | |
127 | ||
128 | switch (frametype & 0x0F) { | |
129 | case NR_CONNREQ: | |
130 | len += 17; | |
131 | break; | |
132 | case NR_CONNACK: | |
133 | len += (nr->bpqext) ? 2 : 1; | |
134 | break; | |
135 | case NR_DISCREQ: | |
136 | case NR_DISCACK: | |
137 | case NR_INFOACK: | |
138 | break; | |
139 | default: | |
140 | printk(KERN_ERR "NET/ROM: nr_write_internal - invalid frame type %d\n", frametype); | |
141 | return; | |
142 | } | |
143 | ||
144 | if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL) | |
145 | return; | |
146 | ||
147 | /* | |
148 | * Space for AX.25 and NET/ROM network header | |
149 | */ | |
150 | skb_reserve(skb, NR_NETWORK_LEN); | |
151 | ||
152 | dptr = skb_put(skb, skb_tailroom(skb)); | |
153 | ||
154 | switch (frametype & 0x0F) { | |
155 | case NR_CONNREQ: | |
156 | timeout = nr->t1 / HZ; | |
157 | *dptr++ = nr->my_index; | |
158 | *dptr++ = nr->my_id; | |
159 | *dptr++ = 0; | |
160 | *dptr++ = 0; | |
161 | *dptr++ = frametype; | |
162 | *dptr++ = nr->window; | |
163 | memcpy(dptr, &nr->user_addr, AX25_ADDR_LEN); | |
164 | dptr[6] &= ~AX25_CBIT; | |
165 | dptr[6] &= ~AX25_EBIT; | |
166 | dptr[6] |= AX25_SSSID_SPARE; | |
167 | dptr += AX25_ADDR_LEN; | |
168 | memcpy(dptr, &nr->source_addr, AX25_ADDR_LEN); | |
169 | dptr[6] &= ~AX25_CBIT; | |
170 | dptr[6] &= ~AX25_EBIT; | |
171 | dptr[6] |= AX25_SSSID_SPARE; | |
172 | dptr += AX25_ADDR_LEN; | |
173 | *dptr++ = timeout % 256; | |
174 | *dptr++ = timeout / 256; | |
175 | break; | |
176 | ||
177 | case NR_CONNACK: | |
178 | *dptr++ = nr->your_index; | |
179 | *dptr++ = nr->your_id; | |
180 | *dptr++ = nr->my_index; | |
181 | *dptr++ = nr->my_id; | |
182 | *dptr++ = frametype; | |
183 | *dptr++ = nr->window; | |
184 | if (nr->bpqext) *dptr++ = sysctl_netrom_network_ttl_initialiser; | |
185 | break; | |
186 | ||
187 | case NR_DISCREQ: | |
188 | case NR_DISCACK: | |
189 | *dptr++ = nr->your_index; | |
190 | *dptr++ = nr->your_id; | |
191 | *dptr++ = 0; | |
192 | *dptr++ = 0; | |
193 | *dptr++ = frametype; | |
194 | break; | |
195 | ||
196 | case NR_INFOACK: | |
197 | *dptr++ = nr->your_index; | |
198 | *dptr++ = nr->your_id; | |
199 | *dptr++ = 0; | |
200 | *dptr++ = nr->vr; | |
201 | *dptr++ = frametype; | |
202 | break; | |
203 | } | |
204 | ||
205 | nr_transmit_buffer(sk, skb); | |
206 | } | |
207 | ||
208 | /* | |
e21ce8c7 | 209 | * This routine is called to send an error reply. |
1da177e4 | 210 | */ |
e21ce8c7 | 211 | void __nr_transmit_reply(struct sk_buff *skb, int mine, unsigned char cmdflags) |
1da177e4 LT |
212 | { |
213 | struct sk_buff *skbn; | |
214 | unsigned char *dptr; | |
215 | int len; | |
216 | ||
217 | len = NR_NETWORK_LEN + NR_TRANSPORT_LEN + 1; | |
218 | ||
219 | if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL) | |
220 | return; | |
221 | ||
222 | skb_reserve(skbn, 0); | |
223 | ||
224 | dptr = skb_put(skbn, NR_NETWORK_LEN + NR_TRANSPORT_LEN); | |
225 | ||
d626f62b | 226 | skb_copy_from_linear_data_offset(skb, 7, dptr, AX25_ADDR_LEN); |
1da177e4 LT |
227 | dptr[6] &= ~AX25_CBIT; |
228 | dptr[6] &= ~AX25_EBIT; | |
229 | dptr[6] |= AX25_SSSID_SPARE; | |
230 | dptr += AX25_ADDR_LEN; | |
231 | ||
d626f62b | 232 | skb_copy_from_linear_data(skb, dptr, AX25_ADDR_LEN); |
1da177e4 LT |
233 | dptr[6] &= ~AX25_CBIT; |
234 | dptr[6] |= AX25_EBIT; | |
235 | dptr[6] |= AX25_SSSID_SPARE; | |
236 | dptr += AX25_ADDR_LEN; | |
237 | ||
238 | *dptr++ = sysctl_netrom_network_ttl_initialiser; | |
239 | ||
240 | if (mine) { | |
241 | *dptr++ = 0; | |
242 | *dptr++ = 0; | |
243 | *dptr++ = skb->data[15]; | |
244 | *dptr++ = skb->data[16]; | |
245 | } else { | |
246 | *dptr++ = skb->data[15]; | |
247 | *dptr++ = skb->data[16]; | |
248 | *dptr++ = 0; | |
249 | *dptr++ = 0; | |
250 | } | |
251 | ||
e21ce8c7 | 252 | *dptr++ = cmdflags; |
1da177e4 LT |
253 | *dptr++ = 0; |
254 | ||
255 | if (!nr_route_frame(skbn, NULL)) | |
256 | kfree_skb(skbn); | |
257 | } | |
258 | ||
259 | void nr_disconnect(struct sock *sk, int reason) | |
260 | { | |
261 | nr_stop_t1timer(sk); | |
262 | nr_stop_t2timer(sk); | |
263 | nr_stop_t4timer(sk); | |
264 | nr_stop_idletimer(sk); | |
265 | ||
266 | nr_clear_queues(sk); | |
267 | ||
268 | nr_sk(sk)->state = NR_STATE_0; | |
269 | ||
270 | sk->sk_state = TCP_CLOSE; | |
271 | sk->sk_err = reason; | |
272 | sk->sk_shutdown |= SEND_SHUTDOWN; | |
273 | ||
274 | if (!sock_flag(sk, SOCK_DEAD)) { | |
275 | sk->sk_state_change(sk); | |
276 | sock_set_flag(sk, SOCK_DEAD); | |
277 | } | |
278 | } |