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