1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
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> |
11 | #include <linux/timer.h> |
12 | #include <linux/string.h> |
13 | #include <linux/sockios.h> |
14 | #include <linux/net.h> |
15 | #include <linux/slab.h> |
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> |
21 | #include <net/tcp_states.h> |
22 | #include <linux/uaccess.h> |
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(list: &sk->sk_write_queue); |
36 | skb_queue_purge(list: &nr->ack_queue); |
37 | skb_queue_purge(list: &nr->reseq_queue); |
38 | skb_queue_purge(list: &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(list_: &nrom->ack_queue) != NULL && nrom->va != nr) { |
56 | skb = skb_dequeue(list: &nrom->ack_queue); |
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(list: &nr_sk(sk)->ack_queue)) != NULL) { |
73 | if (skb_prev == NULL) |
74 | skb_queue_head(list: &sk->sk_write_queue, newsk: skb); |
75 | else |
76 | skb_append(old: skb_prev, newsk: skb, list: &sk->sk_write_queue); |
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_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 | skb = alloc_skb(NR_NETWORK_LEN + len, GFP_ATOMIC); |
145 | if (!skb) |
146 | return; |
147 | |
148 | /* |
149 | * Space for AX.25 and NET/ROM network header |
150 | */ |
151 | skb_reserve(skb, NR_NETWORK_LEN); |
152 | |
153 | dptr = skb_put(skb, len); |
154 | |
155 | switch (frametype & 0x0F) { |
156 | case NR_CONNREQ: |
157 | timeout = nr->t1 / HZ; |
158 | *dptr++ = nr->my_index; |
159 | *dptr++ = nr->my_id; |
160 | *dptr++ = 0; |
161 | *dptr++ = 0; |
162 | *dptr++ = frametype; |
163 | *dptr++ = nr->window; |
164 | memcpy(dptr, &nr->user_addr, AX25_ADDR_LEN); |
165 | dptr[6] &= ~AX25_CBIT; |
166 | dptr[6] &= ~AX25_EBIT; |
167 | dptr[6] |= AX25_SSSID_SPARE; |
168 | dptr += AX25_ADDR_LEN; |
169 | memcpy(dptr, &nr->source_addr, AX25_ADDR_LEN); |
170 | dptr[6] &= ~AX25_CBIT; |
171 | dptr[6] &= ~AX25_EBIT; |
172 | dptr[6] |= AX25_SSSID_SPARE; |
173 | dptr += AX25_ADDR_LEN; |
174 | *dptr++ = timeout % 256; |
175 | *dptr++ = timeout / 256; |
176 | break; |
177 | |
178 | case NR_CONNACK: |
179 | *dptr++ = nr->your_index; |
180 | *dptr++ = nr->your_id; |
181 | *dptr++ = nr->my_index; |
182 | *dptr++ = nr->my_id; |
183 | *dptr++ = frametype; |
184 | *dptr++ = nr->window; |
185 | if (nr->bpqext) |
186 | *dptr++ = READ_ONCE(sysctl_netrom_network_ttl_initialiser); |
187 | break; |
188 | |
189 | case NR_DISCREQ: |
190 | case NR_DISCACK: |
191 | *dptr++ = nr->your_index; |
192 | *dptr++ = nr->your_id; |
193 | *dptr++ = 0; |
194 | *dptr++ = 0; |
195 | *dptr++ = frametype; |
196 | break; |
197 | |
198 | case NR_INFOACK: |
199 | *dptr++ = nr->your_index; |
200 | *dptr++ = nr->your_id; |
201 | *dptr++ = 0; |
202 | *dptr++ = nr->vr; |
203 | *dptr++ = frametype; |
204 | break; |
205 | } |
206 | |
207 | nr_transmit_buffer(sk, skb); |
208 | } |
209 | |
210 | /* |
211 | * This routine is called to send an error reply. |
212 | */ |
213 | void __nr_transmit_reply(struct sk_buff *skb, int mine, unsigned char cmdflags) |
214 | { |
215 | struct sk_buff *skbn; |
216 | unsigned char *dptr; |
217 | int len; |
218 | |
219 | len = NR_NETWORK_LEN + NR_TRANSPORT_LEN + 1; |
220 | |
221 | if ((skbn = alloc_skb(size: len, GFP_ATOMIC)) == NULL) |
222 | return; |
223 | |
224 | skb_reserve(skb: skbn, len: 0); |
225 | |
226 | dptr = skb_put(skb: skbn, NR_NETWORK_LEN + NR_TRANSPORT_LEN); |
227 | |
228 | skb_copy_from_linear_data_offset(skb, offset: 7, to: dptr, AX25_ADDR_LEN); |
229 | dptr[6] &= ~AX25_CBIT; |
230 | dptr[6] &= ~AX25_EBIT; |
231 | dptr[6] |= AX25_SSSID_SPARE; |
232 | dptr += AX25_ADDR_LEN; |
233 | |
234 | skb_copy_from_linear_data(skb, to: dptr, AX25_ADDR_LEN); |
235 | dptr[6] &= ~AX25_CBIT; |
236 | dptr[6] |= AX25_EBIT; |
237 | dptr[6] |= AX25_SSSID_SPARE; |
238 | dptr += AX25_ADDR_LEN; |
239 | |
240 | *dptr++ = READ_ONCE(sysctl_netrom_network_ttl_initialiser); |
241 | |
242 | if (mine) { |
243 | *dptr++ = 0; |
244 | *dptr++ = 0; |
245 | *dptr++ = skb->data[15]; |
246 | *dptr++ = skb->data[16]; |
247 | } else { |
248 | *dptr++ = skb->data[15]; |
249 | *dptr++ = skb->data[16]; |
250 | *dptr++ = 0; |
251 | *dptr++ = 0; |
252 | } |
253 | |
254 | *dptr++ = cmdflags; |
255 | *dptr++ = 0; |
256 | |
257 | if (!nr_route_frame(skbn, NULL)) |
258 | kfree_skb(skb: skbn); |
259 | } |
260 | |
261 | void nr_disconnect(struct sock *sk, int reason) |
262 | { |
263 | nr_stop_t1timer(sk); |
264 | nr_stop_t2timer(sk); |
265 | nr_stop_t4timer(sk); |
266 | nr_stop_idletimer(sk); |
267 | |
268 | nr_clear_queues(sk); |
269 | |
270 | nr_sk(sk)->state = NR_STATE_0; |
271 | |
272 | sk->sk_state = TCP_CLOSE; |
273 | sk->sk_err = reason; |
274 | sk->sk_shutdown |= SEND_SHUTDOWN; |
275 | |
276 | if (!sock_flag(sk, flag: SOCK_DEAD)) { |
277 | sk->sk_state_change(sk); |
278 | sock_set_flag(sk, flag: SOCK_DEAD); |
279 | } |
280 | } |
281 | |