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