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(addr: 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(size: 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: &new_frwd->node, head: &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(nb: 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(entry: &fwd->node); |
137 | kfree(objp: 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(entry: &fwd->node); |
153 | kfree(objp: fwd); |
154 | } |
155 | } |
156 | write_unlock_bh(&x25_forward_list_lock); |
157 | } |
158 | |