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(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_frwd->node, &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(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(&fwd->node); 137 kfree(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(&fwd->node); 153 kfree(fwd); 154 } 155 } 156 write_unlock_bh(&x25_forward_list_lock); 157 } 158