1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * History
4 * 03-01-2007 Added forwarding for x.25 Andrew Hendry
5 */
6
7 #define pr_fmt(fmt) "X25: " fmt
8
9 #include <linux/if_arp.h>
10 #include <linux/init.h>
11 #include <linux/slab.h>
12 #include <net/x25.h>
13
14 LIST_HEAD(x25_forward_list);
15 DEFINE_RWLOCK(x25_forward_list_lock);
16
17 int x25_forward_call(struct x25_address *dest_addr, struct x25_neigh *from,
18 struct sk_buff *skb, int lci)
19 {
20 struct x25_route *rt;
21 struct x25_neigh *neigh_new = NULL;
22 struct x25_forward *x25_frwd, *new_frwd;
23 struct sk_buff *skbn;
24 short same_lci = 0;
25 int rc = 0;
26
27 if ((rt = x25_get_route(dest_addr)) == NULL)
28 goto out_no_route;
29
30 if ((neigh_new = x25_get_neigh(rt->dev)) == NULL) {
31 /* This shouldn't happen, if it occurs somehow
32 * do something sensible
33 */
34 goto out_put_route;
35 }
36
37 /* Avoid a loop. This is the normal exit path for a
38 * system with only one x.25 iface and default route
39 */
40 if (rt->dev == from->dev) {
41 goto out_put_nb;
42 }
43
44 /* Remote end sending a call request on an already
45 * established LCI? It shouldn't happen, just in case..
46 */
47 read_lock_bh(&x25_forward_list_lock);
48 list_for_each_entry(x25_frwd, &x25_forward_list, node) {
49 if (x25_frwd->lci == lci) {
50 pr_warn("call request for lci which is already registered!, transmitting but not registering new pair\n");
51 same_lci = 1;
52 }
53 }
54 read_unlock_bh(&x25_forward_list_lock);
55
56 /* Save the forwarding details for future traffic */
57 if (!same_lci){
58 if ((new_frwd = kmalloc(sizeof(struct x25_forward),
59 GFP_ATOMIC)) == NULL){
60 rc = -ENOMEM;
61 goto out_put_nb;
62 }
63 new_frwd->lci = lci;
64 new_frwd->dev1 = rt->dev;
65 new_frwd->dev2 = from->dev;
66 write_lock_bh(&x25_forward_list_lock);
67 list_add(&new_frwd->node, &x25_forward_list);
68 write_unlock_bh(&x25_forward_list_lock);
69 }
70
71 /* Forward the call request */
72 if ( (skbn = skb_clone(skb, GFP_ATOMIC)) == NULL){
73 goto out_put_nb;
74 }
75 x25_transmit_link(skbn, neigh_new);
76 rc = 1;
77
78
79 out_put_nb:
80 x25_neigh_put(neigh_new);
81
82 out_put_route:
83 x25_route_put(rt);
84
85 out_no_route:
86 return rc;
87 }
88
89
90 int x25_forward_data(int lci, struct x25_neigh *from, struct sk_buff *skb) {
91
92 struct x25_forward *frwd;
93 struct net_device *peer = NULL;
94 struct x25_neigh *nb;
95 struct sk_buff *skbn;
96 int rc = 0;
97
98 read_lock_bh(&x25_forward_list_lock);
99 list_for_each_entry(frwd, &x25_forward_list, node) {
100 if (frwd->lci == lci) {
101 /* The call is established, either side can send */
102 if (from->dev == frwd->dev1) {
103 peer = frwd->dev2;
104 } else {
105 peer = frwd->dev1;
106 }
107 break;
108 }
109 }
110 read_unlock_bh(&x25_forward_list_lock);
111
112 if ( (nb = x25_get_neigh(peer)) == NULL)
113 goto out;
114
115 if ( (skbn = pskb_copy(skb, GFP_ATOMIC)) == NULL){
116 goto output;
117
118 }
119 x25_transmit_link(skbn, nb);
120
121 rc = 1;
122 output:
123 x25_neigh_put(nb);
124 out:
125 return rc;
126 }
127
128 void x25_clear_forward_by_lci(unsigned int lci)
129 {
130 struct x25_forward *fwd, *tmp;
131
132 write_lock_bh(&x25_forward_list_lock);
133
134 list_for_each_entry_safe(fwd, tmp, &x25_forward_list, node) {
135 if (fwd->lci == lci) {
136 list_del(&fwd->node);
137 kfree(fwd);
138 }
139 }
140 write_unlock_bh(&x25_forward_list_lock);
141 }
142
143
144 void x25_clear_forward_by_dev(struct net_device *dev)
145 {
146 struct x25_forward *fwd, *tmp;
147
148 write_lock_bh(&x25_forward_list_lock);
149
150 list_for_each_entry_safe(fwd, tmp, &x25_forward_list, node) {
151 if ((fwd->dev1 == dev) || (fwd->dev2 == dev)){
152 list_del(&fwd->node);
153 kfree(fwd);
154 }
155 }
156 write_unlock_bh(&x25_forward_list_lock);
157 }
158
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