1/*
2 *	This module:
3 *		This module is free software; you can redistribute it and/or
4 *		modify it under the terms of the GNU General Public License
5 *		as published by the Free Software Foundation; either version
6 *		2 of the License, or (at your option) any later version.
7 *
8 *	History
9 *	03-01-2007	Added forwarding for x.25	Andrew Hendry
10 */
11
12#define pr_fmt(fmt) "X25: " fmt
13
14#include <linux/if_arp.h>
15#include <linux/init.h>
16#include <linux/slab.h>
17#include <net/x25.h>
18
19LIST_HEAD(x25_forward_list);
20DEFINE_RWLOCK(x25_forward_list_lock);
21
22int x25_forward_call(struct x25_address *dest_addr, struct x25_neigh *from,
23			struct sk_buff *skb, int lci)
24{
25	struct x25_route *rt;
26	struct x25_neigh *neigh_new = NULL;
27	struct list_head *entry;
28	struct x25_forward *x25_frwd, *new_frwd;
29	struct sk_buff *skbn;
30	short same_lci = 0;
31	int rc = 0;
32
33	if ((rt = x25_get_route(dest_addr)) == NULL)
34		goto out_no_route;
35
36	if ((neigh_new = x25_get_neigh(rt->dev)) == NULL) {
37		/* This shouldn't happen, if it occurs somehow
38		 * do something sensible
39		 */
40		goto out_put_route;
41	}
42
43	/* Avoid a loop. This is the normal exit path for a
44	 * system with only one x.25 iface and default route
45	 */
46	if (rt->dev == from->dev) {
47		goto out_put_nb;
48	}
49
50	/* Remote end sending a call request on an already
51	 * established LCI? It shouldn't happen, just in case..
52	 */
53	read_lock_bh(&x25_forward_list_lock);
54	list_for_each(entry, &x25_forward_list) {
55		x25_frwd = list_entry(entry, struct x25_forward, node);
56		if (x25_frwd->lci == lci) {
57			pr_warn("call request for lci which is already registered!, transmitting but not registering new pair\n");
58			same_lci = 1;
59		}
60	}
61	read_unlock_bh(&x25_forward_list_lock);
62
63	/* Save the forwarding details for future traffic */
64	if (!same_lci){
65		if ((new_frwd = kmalloc(sizeof(struct x25_forward),
66						GFP_ATOMIC)) == NULL){
67			rc = -ENOMEM;
68			goto out_put_nb;
69		}
70		new_frwd->lci = lci;
71		new_frwd->dev1 = rt->dev;
72		new_frwd->dev2 = from->dev;
73		write_lock_bh(&x25_forward_list_lock);
74		list_add(&new_frwd->node, &x25_forward_list);
75		write_unlock_bh(&x25_forward_list_lock);
76	}
77
78	/* Forward the call request */
79	if ( (skbn = skb_clone(skb, GFP_ATOMIC)) == NULL){
80		goto out_put_nb;
81	}
82	x25_transmit_link(skbn, neigh_new);
83	rc = 1;
84
85
86out_put_nb:
87	x25_neigh_put(neigh_new);
88
89out_put_route:
90	x25_route_put(rt);
91
92out_no_route:
93	return rc;
94}
95
96
97int x25_forward_data(int lci, struct x25_neigh *from, struct sk_buff *skb) {
98
99	struct x25_forward *frwd;
100	struct list_head *entry;
101	struct net_device *peer = NULL;
102	struct x25_neigh *nb;
103	struct sk_buff *skbn;
104	int rc = 0;
105
106	read_lock_bh(&x25_forward_list_lock);
107	list_for_each(entry, &x25_forward_list) {
108		frwd = list_entry(entry, struct x25_forward, node);
109		if (frwd->lci == lci) {
110			/* The call is established, either side can send */
111			if (from->dev == frwd->dev1) {
112				peer = frwd->dev2;
113			} else {
114				peer = frwd->dev1;
115			}
116			break;
117		}
118	}
119	read_unlock_bh(&x25_forward_list_lock);
120
121	if ( (nb = x25_get_neigh(peer)) == NULL)
122		goto out;
123
124	if ( (skbn = pskb_copy(skb, GFP_ATOMIC)) == NULL){
125		goto output;
126
127	}
128	x25_transmit_link(skbn, nb);
129
130	rc = 1;
131output:
132	x25_neigh_put(nb);
133out:
134	return rc;
135}
136
137void x25_clear_forward_by_lci(unsigned int lci)
138{
139	struct x25_forward *fwd;
140	struct list_head *entry, *tmp;
141
142	write_lock_bh(&x25_forward_list_lock);
143
144	list_for_each_safe(entry, tmp, &x25_forward_list) {
145		fwd = list_entry(entry, struct x25_forward, node);
146		if (fwd->lci == lci) {
147			list_del(&fwd->node);
148			kfree(fwd);
149		}
150	}
151	write_unlock_bh(&x25_forward_list_lock);
152}
153
154
155void x25_clear_forward_by_dev(struct net_device *dev)
156{
157	struct x25_forward *fwd;
158	struct list_head *entry, *tmp;
159
160	write_lock_bh(&x25_forward_list_lock);
161
162	list_for_each_safe(entry, tmp, &x25_forward_list) {
163		fwd = list_entry(entry, struct x25_forward, node);
164		if ((fwd->dev1 == dev) || (fwd->dev2 == dev)){
165			list_del(&fwd->node);
166			kfree(fwd);
167		}
168	}
169	write_unlock_bh(&x25_forward_list_lock);
170}
171