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_obj(struct x25_forward, GFP_ATOMIC)) == NULL){ 59 rc = -ENOMEM; 60 goto out_put_nb; 61 } 62 new_frwd->lci = lci; 63 new_frwd->dev1 = rt->dev; 64 new_frwd->dev2 = from->dev; 65 write_lock_bh(&x25_forward_list_lock); 66 list_add(&new_frwd->node, &x25_forward_list); 67 write_unlock_bh(&x25_forward_list_lock); 68 } 69 70 /* Forward the call request */ 71 if ( (skbn = skb_clone(skb, GFP_ATOMIC)) == NULL){ 72 goto out_put_nb; 73 } 74 x25_transmit_link(skbn, neigh_new); 75 rc = 1; 76 77 78 out_put_nb: 79 x25_neigh_put(neigh_new); 80 81 out_put_route: 82 x25_route_put(rt); 83 84 out_no_route: 85 return rc; 86 } 87 88 89 int x25_forward_data(int lci, struct x25_neigh *from, struct sk_buff *skb) { 90 91 struct x25_forward *frwd; 92 struct net_device *peer = NULL; 93 struct x25_neigh *nb; 94 struct sk_buff *skbn; 95 int rc = 0; 96 97 read_lock_bh(&x25_forward_list_lock); 98 list_for_each_entry(frwd, &x25_forward_list, node) { 99 if (frwd->lci == lci) { 100 /* The call is established, either side can send */ 101 if (from->dev == frwd->dev1) { 102 peer = frwd->dev2; 103 } else { 104 peer = frwd->dev1; 105 } 106 break; 107 } 108 } 109 read_unlock_bh(&x25_forward_list_lock); 110 111 if ( (nb = x25_get_neigh(peer)) == NULL) 112 goto out; 113 114 if ( (skbn = pskb_copy(skb, GFP_ATOMIC)) == NULL){ 115 goto output; 116 117 } 118 x25_transmit_link(skbn, nb); 119 120 rc = 1; 121 output: 122 x25_neigh_put(nb); 123 out: 124 return rc; 125 } 126 127 void x25_clear_forward_by_lci(unsigned int lci) 128 { 129 struct x25_forward *fwd, *tmp; 130 131 write_lock_bh(&x25_forward_list_lock); 132 133 list_for_each_entry_safe(fwd, tmp, &x25_forward_list, node) { 134 if (fwd->lci == lci) { 135 list_del(&fwd->node); 136 kfree(fwd); 137 } 138 } 139 write_unlock_bh(&x25_forward_list_lock); 140 } 141 142 143 void x25_clear_forward_by_dev(struct net_device *dev) 144 { 145 struct x25_forward *fwd, *tmp; 146 147 write_lock_bh(&x25_forward_list_lock); 148 149 list_for_each_entry_safe(fwd, tmp, &x25_forward_list, node) { 150 if ((fwd->dev1 == dev) || (fwd->dev2 == dev)){ 151 list_del(&fwd->node); 152 kfree(fwd); 153 } 154 } 155 write_unlock_bh(&x25_forward_list_lock); 156 } 157