GNU Linux-libre 4.14.266-gnu1
[releases.git] / net / x25 / x25_forward.c
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
19 LIST_HEAD(x25_forward_list);
20 DEFINE_RWLOCK(x25_forward_list_lock);
21
22 int 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
86 out_put_nb:
87         x25_neigh_put(neigh_new);
88
89 out_put_route:
90         x25_route_put(rt);
91
92 out_no_route:
93         return rc;
94 }
95
96
97 int 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;
131 output:
132         x25_neigh_put(nb);
133 out:
134         return rc;
135 }
136
137 void 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
155 void 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 }