1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 *
4 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
5 */
6 #include <linux/types.h>
7 #include <linux/slab.h>
8 #include <linux/socket.h>
9 #include <linux/timer.h>
10 #include <net/ax25.h>
11 #include <linux/skbuff.h>
12 #include <net/rose.h>
13 #include <linux/init.h>
14
15 static struct sk_buff_head loopback_queue;
16 #define ROSE_LOOPBACK_LIMIT 1000
17 static struct timer_list loopback_timer;
18
19 static void rose_set_loopback_timer(void);
20 static void rose_loopback_timer(struct timer_list *unused);
21
rose_loopback_init(void)22 void rose_loopback_init(void)
23 {
24 skb_queue_head_init(&loopback_queue);
25
26 timer_setup(&loopback_timer, rose_loopback_timer, 0);
27 }
28
rose_loopback_running(void)29 static int rose_loopback_running(void)
30 {
31 return timer_pending(&loopback_timer);
32 }
33
rose_loopback_queue(struct sk_buff * skb,struct rose_neigh * neigh)34 int rose_loopback_queue(struct sk_buff *skb, struct rose_neigh *neigh)
35 {
36 struct sk_buff *skbn = NULL;
37
38 if (skb_queue_len(&loopback_queue) < ROSE_LOOPBACK_LIMIT)
39 skbn = skb_clone(skb, GFP_ATOMIC);
40
41 if (skbn) {
42 consume_skb(skb);
43 skb_queue_tail(&loopback_queue, skbn);
44
45 if (!rose_loopback_running())
46 rose_set_loopback_timer();
47 } else {
48 kfree_skb(skb);
49 }
50
51 return 1;
52 }
53
rose_set_loopback_timer(void)54 static void rose_set_loopback_timer(void)
55 {
56 mod_timer(&loopback_timer, jiffies + 10);
57 }
58
rose_loopback_timer(struct timer_list * unused)59 static void rose_loopback_timer(struct timer_list *unused)
60 {
61 struct sk_buff *skb;
62 struct net_device *dev;
63 rose_address *dest;
64 struct sock *sk;
65 unsigned short frametype;
66 unsigned int lci_i, lci_o;
67 int count;
68
69 for (count = 0; count < ROSE_LOOPBACK_LIMIT; count++) {
70 skb = skb_dequeue(&loopback_queue);
71 if (!skb)
72 return;
73 if (skb->len < ROSE_MIN_LEN) {
74 kfree_skb(skb);
75 continue;
76 }
77 lci_i = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
78 frametype = skb->data[2];
79 if (frametype == ROSE_CALL_REQUEST &&
80 (skb->len <= ROSE_CALL_REQ_FACILITIES_OFF ||
81 skb->data[ROSE_CALL_REQ_ADDR_LEN_OFF] !=
82 ROSE_CALL_REQ_ADDR_LEN_VAL)) {
83 kfree_skb(skb);
84 continue;
85 }
86 dest = (rose_address *)(skb->data + ROSE_CALL_REQ_DEST_ADDR_OFF);
87 lci_o = ROSE_DEFAULT_MAXVC + 1 - lci_i;
88
89 skb_reset_transport_header(skb);
90
91 sk = rose_find_socket(lci_o, rose_loopback_neigh);
92 if (sk) {
93 if (rose_process_rx_frame(sk, skb) == 0)
94 kfree_skb(skb);
95 continue;
96 }
97
98 if (frametype == ROSE_CALL_REQUEST) {
99 if (!rose_loopback_neigh->dev &&
100 !rose_loopback_neigh->loopback) {
101 kfree_skb(skb);
102 continue;
103 }
104
105 dev = rose_dev_get(dest);
106 if (!dev) {
107 kfree_skb(skb);
108 continue;
109 }
110
111 if (rose_rx_call_request(skb, dev, rose_loopback_neigh, lci_o) == 0) {
112 dev_put(dev);
113 kfree_skb(skb);
114 }
115 } else {
116 kfree_skb(skb);
117 }
118 }
119 if (!skb_queue_empty(&loopback_queue))
120 mod_timer(&loopback_timer, jiffies + 1);
121 }
122
rose_loopback_clear(void)123 void __exit rose_loopback_clear(void)
124 {
125 struct sk_buff *skb;
126
127 del_timer(&loopback_timer);
128
129 while ((skb = skb_dequeue(&loopback_queue)) != NULL) {
130 skb->sk = NULL;
131 kfree_skb(skb);
132 }
133 }
134