net/ipx/ipx_route.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *      Implements the IPX routing routines.
   4  *      Code moved from af_ipx.c.
   5  *
   6  *      Arnaldo Carvalho de Melo <acme@conectiva.com.br>, 2003
   7  *
   8  *      See net/ipx/ChangeLog.
   9  */
  10
  11 #include <linux/list.h>
  12 #include <linux/route.h>
  13 #include <linux/slab.h>
  14 #include <linux/spinlock.h>
  15
  16 #include <net/ipx.h>
  17 #include <net/sock.h>
  18
  19 LIST_HEAD(ipx_routes);
  20 DEFINE_RWLOCK(ipx_routes_lock);
  21
  22 extern struct ipx_interface *ipx_internal_net;
  23
  24 extern struct ipx_interface *ipxitf_find_using_net(__be32 net);
  25 extern int ipxitf_demux_socket(struct ipx_interface *intrfc,
  26                                struct sk_buff *skb, int copy);
  27 extern int ipxitf_demux_socket(struct ipx_interface *intrfc,
  28                                struct sk_buff *skb, int copy);
  29
  30 struct ipx_route *ipxrtr_lookup(__be32 net)
  31 {
  32         struct ipx_route *r;
  33
  34         read_lock_bh(&ipx_routes_lock);
  35         list_for_each_entry(r, &ipx_routes, node)
  36                 if (r->ir_net == net) {
  37                         ipxrtr_hold(r);
  38                         goto unlock;
  39                 }
  40         r = NULL;
  41 unlock:
  42         read_unlock_bh(&ipx_routes_lock);
  43         return r;
  44 }
  45
  46 /*
  47  * Caller must hold a reference to intrfc
  48  */
  49 int ipxrtr_add_route(__be32 network, struct ipx_interface *intrfc,
  50                      unsigned char *node)
  51 {
  52         struct ipx_route *rt;
  53         int rc;
  54
  55         /* Get a route structure; either existing or create */
  56         rt = ipxrtr_lookup(network);
  57         if (!rt) {
  58                 rt = kmalloc(sizeof(*rt), GFP_ATOMIC);
  59                 rc = -EAGAIN;
  60                 if (!rt)
  61                         goto out;
  62
  63                 refcount_set(&rt->refcnt, 1);
  64                 ipxrtr_hold(rt);
  65                 write_lock_bh(&ipx_routes_lock);
  66                 list_add(&rt->node, &ipx_routes);
  67                 write_unlock_bh(&ipx_routes_lock);
  68         } else {
  69                 rc = -EEXIST;
  70                 if (intrfc == ipx_internal_net)
  71                         goto out_put;
  72         }
  73
  74         rt->ir_net      = network;
  75         rt->ir_intrfc   = intrfc;
  76         if (!node) {
  77                 memset(rt->ir_router_node, '\0', IPX_NODE_LEN);
  78                 rt->ir_routed = 0;
  79         } else {
  80                 memcpy(rt->ir_router_node, node, IPX_NODE_LEN);
  81                 rt->ir_routed = 1;
  82         }
  83
  84         rc = 0;
  85 out_put:
  86         ipxrtr_put(rt);
  87 out:
  88         return rc;
  89 }
  90
  91 void ipxrtr_del_routes(struct ipx_interface *intrfc)
  92 {
  93         struct ipx_route *r, *tmp;
  94
  95         write_lock_bh(&ipx_routes_lock);
  96         list_for_each_entry_safe(r, tmp, &ipx_routes, node)
  97                 if (r->ir_intrfc == intrfc) {
  98                         list_del(&r->node);
  99                         ipxrtr_put(r);
 100                 }
 101         write_unlock_bh(&ipx_routes_lock);
 102 }
 103
 104 static int ipxrtr_create(struct ipx_route_definition *rd)
 105 {
 106         struct ipx_interface *intrfc;
 107         int rc = -ENETUNREACH;
 108
 109         /* Find the appropriate interface */
 110         intrfc = ipxitf_find_using_net(rd->ipx_router_network);
 111         if (!intrfc)
 112                 goto out;
 113         rc = ipxrtr_add_route(rd->ipx_network, intrfc, rd->ipx_router_node);
 114         ipxitf_put(intrfc);
 115 out:
 116         return rc;
 117 }
 118
 119 static int ipxrtr_delete(__be32 net)
 120 {
 121         struct ipx_route *r, *tmp;
 122         int rc;
 123
 124         write_lock_bh(&ipx_routes_lock);
 125         list_for_each_entry_safe(r, tmp, &ipx_routes, node)
 126                 if (r->ir_net == net) {
 127                         /* Directly connected; can't lose route */
 128                         rc = -EPERM;
 129                         if (!r->ir_routed)
 130                                 goto out;
 131                         list_del(&r->node);
 132                         ipxrtr_put(r);
 133                         rc = 0;
 134                         goto out;
 135                 }
 136         rc = -ENOENT;
 137 out:
 138         write_unlock_bh(&ipx_routes_lock);
 139         return rc;
 140 }
 141
 142 /*
 143  * The skb has to be unshared, we'll end up calling ipxitf_send, that'll
 144  * modify the packet
 145  */
 146 int ipxrtr_route_skb(struct sk_buff *skb)
 147 {
 148         struct ipxhdr *ipx = ipx_hdr(skb);
 149         struct ipx_route *r = ipxrtr_lookup(IPX_SKB_CB(skb)->ipx_dest_net);
 150
 151         if (!r) {       /* no known route */
 152                 kfree_skb(skb);
 153                 return 0;
 154         }
 155
 156         ipxitf_hold(r->ir_intrfc);
 157         ipxitf_send(r->ir_intrfc, skb, r->ir_routed ?
 158                         r->ir_router_node : ipx->ipx_dest.node);
 159         ipxitf_put(r->ir_intrfc);
 160         ipxrtr_put(r);
 161
 162         return 0;
 163 }
 164
 165 /*
 166  * Route an outgoing frame from a socket.
 167  */
 168 int ipxrtr_route_packet(struct sock *sk, struct sockaddr_ipx *usipx,
 169                         struct msghdr *msg, size_t len, int noblock)
 170 {
 171         struct sk_buff *skb;
 172         struct ipx_sock *ipxs = ipx_sk(sk);
 173         struct ipx_interface *intrfc;
 174         struct ipxhdr *ipx;
 175         size_t size;
 176         int ipx_offset;
 177         struct ipx_route *rt = NULL;
 178         int rc;
 179
 180         /* Find the appropriate interface on which to send packet */
 181         if (!usipx->sipx_network && ipx_primary_net) {
 182                 usipx->sipx_network = ipx_primary_net->if_netnum;
 183                 intrfc = ipx_primary_net;
 184         } else {
 185                 rt = ipxrtr_lookup(usipx->sipx_network);
 186                 rc = -ENETUNREACH;
 187                 if (!rt)
 188                         goto out;
 189                 intrfc = rt->ir_intrfc;
 190         }
 191
 192         ipxitf_hold(intrfc);
 193         ipx_offset = intrfc->if_ipx_offset;
 194         size = sizeof(struct ipxhdr) + len + ipx_offset;
 195
 196         skb = sock_alloc_send_skb(sk, size, noblock, &rc);
 197         if (!skb)
 198                 goto out_put;
 199
 200         skb_reserve(skb, ipx_offset);
 201         skb->sk = sk;
 202
 203         /* Fill in IPX header */
 204         skb_reset_network_header(skb);
 205         skb_reset_transport_header(skb);
 206         skb_put(skb, sizeof(struct ipxhdr));
 207         ipx = ipx_hdr(skb);
 208         ipx->ipx_pktsize = htons(len + sizeof(struct ipxhdr));
 209         IPX_SKB_CB(skb)->ipx_tctrl = 0;
 210         ipx->ipx_type    = usipx->sipx_type;
 211
 212         IPX_SKB_CB(skb)->last_hop.index = -1;
 213 #ifdef CONFIG_IPX_INTERN
 214         IPX_SKB_CB(skb)->ipx_source_net = ipxs->intrfc->if_netnum;
 215         memcpy(ipx->ipx_source.node, ipxs->node, IPX_NODE_LEN);
 216 #else
 217         rc = ntohs(ipxs->port);
 218         if (rc == 0x453 || rc == 0x452) {
 219                 /* RIP/SAP special handling for mars_nwe */
 220                 IPX_SKB_CB(skb)->ipx_source_net = intrfc->if_netnum;
 221                 memcpy(ipx->ipx_source.node, intrfc->if_node, IPX_NODE_LEN);
 222         } else {
 223                 IPX_SKB_CB(skb)->ipx_source_net = ipxs->intrfc->if_netnum;
 224                 memcpy(ipx->ipx_source.node, ipxs->intrfc->if_node,
 225                         IPX_NODE_LEN);
 226         }
 227 #endif  /* CONFIG_IPX_INTERN */
 228         ipx->ipx_source.sock            = ipxs->port;
 229         IPX_SKB_CB(skb)->ipx_dest_net   = usipx->sipx_network;
 230         memcpy(ipx->ipx_dest.node, usipx->sipx_node, IPX_NODE_LEN);
 231         ipx->ipx_dest.sock              = usipx->sipx_port;
 232
 233         rc = memcpy_from_msg(skb_put(skb, len), msg, len);
 234         if (rc) {
 235                 kfree_skb(skb);
 236                 goto out_put;
 237         }
 238
 239         /* Apply checksum. Not allowed on 802.3 links. */
 240         if (sk->sk_no_check_tx ||
 241             intrfc->if_dlink_type == htons(IPX_FRAME_8023))
 242                 ipx->ipx_checksum = htons(0xFFFF);
 243         else
 244                 ipx->ipx_checksum = ipx_cksum(ipx, len + sizeof(struct ipxhdr));
 245
 246         rc = ipxitf_send(intrfc, skb, (rt && rt->ir_routed) ?
 247                          rt->ir_router_node : ipx->ipx_dest.node);
 248 out_put:
 249         ipxitf_put(intrfc);
 250         if (rt)
 251                 ipxrtr_put(rt);
 252 out:
 253         return rc;
 254 }
 255
 256 /*
 257  * We use a normal struct rtentry for route handling
 258  */
 259 int ipxrtr_ioctl(unsigned int cmd, void __user *arg)
 260 {
 261         struct rtentry rt;      /* Use these to behave like 'other' stacks */
 262         struct sockaddr_ipx *sg, *st;
 263         int rc = -EFAULT;
 264
 265         if (copy_from_user(&rt, arg, sizeof(rt)))
 266                 goto out;
 267
 268         sg = (struct sockaddr_ipx *)&rt.rt_gateway;
 269         st = (struct sockaddr_ipx *)&rt.rt_dst;
 270
 271         rc = -EINVAL;
 272         if (!(rt.rt_flags & RTF_GATEWAY) || /* Direct routes are fixed */
 273             sg->sipx_family != AF_IPX ||
 274             st->sipx_family != AF_IPX)
 275                 goto out;
 276
 277         switch (cmd) {
 278         case SIOCDELRT:
 279                 rc = ipxrtr_delete(st->sipx_network);
 280                 break;
 281         case SIOCADDRT: {
 282                 struct ipx_route_definition f;
 283                 f.ipx_network           = st->sipx_network;
 284                 f.ipx_router_network    = sg->sipx_network;
 285                 memcpy(f.ipx_router_node, sg->sipx_node, IPX_NODE_LEN);
 286                 rc = ipxrtr_create(&f);
 287                 break;
 288         }
 289         }
 290
 291 out:
 292         return rc;
 293 }