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
15static struct sk_buff_head loopback_queue;
16#define ROSE_LOOPBACK_LIMIT 1000
17static struct timer_list loopback_timer;
18
19static void rose_set_loopback_timer(void);
20static void rose_loopback_timer(struct timer_list *unused);
21
22void rose_loopback_init(void)
23{
24	skb_queue_head_init(&loopback_queue);
25
26	timer_setup(&loopback_timer, rose_loopback_timer, 0);
27}
28
29static int rose_loopback_running(void)
30{
31	return timer_pending(&loopback_timer);
32}
33
34int 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
54static void rose_set_loopback_timer(void)
55{
56	mod_timer(&loopback_timer, jiffies + 10);
57}
58
59static 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
123void __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