// SPDX-License-Identifier: GPL-2.0

  /*
   *	Implements the IPX routing routines.
   *	Code moved from af_ipx.c.
   *
   *	Arnaldo Carvalho de Melo <acme@conectiva.com.br>, 2003
   *
   *	See net/ipx/ChangeLog.
   */

  #include <linux/list.h>
  #include <linux/route.h>

  #include <linux/slab.h>

  #include <linux/spinlock.h>
  
  #include <net/ipx.h>
  #include <net/sock.h>
  
  LIST_HEAD(ipx_routes);
  DEFINE_RWLOCK(ipx_routes_lock);
  
  extern struct ipx_interface *ipx_internal_net;

  extern struct ipx_interface *ipxitf_find_using_net(__be32 net);

  extern int ipxitf_demux_socket(struct ipx_interface *intrfc,
  			       struct sk_buff *skb, int copy);
  extern int ipxitf_demux_socket(struct ipx_interface *intrfc,
  			       struct sk_buff *skb, int copy);

  struct ipx_route *ipxrtr_lookup(__be32 net)

  {
  	struct ipx_route *r;
  
  	read_lock_bh(&ipx_routes_lock);
  	list_for_each_entry(r, &ipx_routes, node)
  		if (r->ir_net == net) {
  			ipxrtr_hold(r);
  			goto unlock;
  		}
  	r = NULL;
  unlock:
  	read_unlock_bh(&ipx_routes_lock);
  	return r;
  }
  
  /*
   * Caller must hold a reference to intrfc
   */

  int ipxrtr_add_route(__be32 network, struct ipx_interface *intrfc,

  		     unsigned char *node)
  {
  	struct ipx_route *rt;
  	int rc;
  
  	/* Get a route structure; either existing or create */
  	rt = ipxrtr_lookup(network);
  	if (!rt) {
  		rt = kmalloc(sizeof(*rt), GFP_ATOMIC);
  		rc = -EAGAIN;
  		if (!rt)
  			goto out;

  		refcount_set(&rt->refcnt, 1);

  		ipxrtr_hold(rt);
  		write_lock_bh(&ipx_routes_lock);
  		list_add(&rt->node, &ipx_routes);
  		write_unlock_bh(&ipx_routes_lock);
  	} else {
  		rc = -EEXIST;
  		if (intrfc == ipx_internal_net)
  			goto out_put;
  	}
  
  	rt->ir_net 	= network;
  	rt->ir_intrfc 	= intrfc;
  	if (!node) {
  		memset(rt->ir_router_node, '\0', IPX_NODE_LEN);
  		rt->ir_routed = 0;
  	} else {
  		memcpy(rt->ir_router_node, node, IPX_NODE_LEN);
  		rt->ir_routed = 1;
  	}
  
  	rc = 0;
  out_put:
  	ipxrtr_put(rt);
  out:
  	return rc;
  }
  
  void ipxrtr_del_routes(struct ipx_interface *intrfc)
  {
  	struct ipx_route *r, *tmp;
  
  	write_lock_bh(&ipx_routes_lock);
  	list_for_each_entry_safe(r, tmp, &ipx_routes, node)
  		if (r->ir_intrfc == intrfc) {
  			list_del(&r->node);
  			ipxrtr_put(r);
  		}
  	write_unlock_bh(&ipx_routes_lock);
  }
  
  static int ipxrtr_create(struct ipx_route_definition *rd)
  {
  	struct ipx_interface *intrfc;
  	int rc = -ENETUNREACH;
  
  	/* Find the appropriate interface */
  	intrfc = ipxitf_find_using_net(rd->ipx_router_network);
  	if (!intrfc)
  		goto out;
  	rc = ipxrtr_add_route(rd->ipx_network, intrfc, rd->ipx_router_node);
  	ipxitf_put(intrfc);
  out:
  	return rc;
  }

  static int ipxrtr_delete(__be32 net)

  {
  	struct ipx_route *r, *tmp;
  	int rc;
  
  	write_lock_bh(&ipx_routes_lock);
  	list_for_each_entry_safe(r, tmp, &ipx_routes, node)
  		if (r->ir_net == net) {
  			/* Directly connected; can't lose route */
  			rc = -EPERM;
  			if (!r->ir_routed)
  				goto out;
  			list_del(&r->node);
  			ipxrtr_put(r);
  			rc = 0;
  			goto out;
  		}
  	rc = -ENOENT;
  out:
  	write_unlock_bh(&ipx_routes_lock);
  	return rc;
  }
  
  /*
   * The skb has to be unshared, we'll end up calling ipxitf_send, that'll
   * modify the packet
   */
  int ipxrtr_route_skb(struct sk_buff *skb)
  {
  	struct ipxhdr *ipx = ipx_hdr(skb);
  	struct ipx_route *r = ipxrtr_lookup(IPX_SKB_CB(skb)->ipx_dest_net);
  
  	if (!r) {	/* no known route */
  		kfree_skb(skb);
  		return 0;
  	}
  
  	ipxitf_hold(r->ir_intrfc);
  	ipxitf_send(r->ir_intrfc, skb, r->ir_routed ?
  			r->ir_router_node : ipx->ipx_dest.node);
  	ipxitf_put(r->ir_intrfc);
  	ipxrtr_put(r);
  
  	return 0;
  }
  
  /*
   * Route an outgoing frame from a socket.
   */
  int ipxrtr_route_packet(struct sock *sk, struct sockaddr_ipx *usipx,

  			struct msghdr *msg, size_t len, int noblock)

  {
  	struct sk_buff *skb;
  	struct ipx_sock *ipxs = ipx_sk(sk);
  	struct ipx_interface *intrfc;
  	struct ipxhdr *ipx;
  	size_t size;
  	int ipx_offset;
  	struct ipx_route *rt = NULL;
  	int rc;
  
  	/* Find the appropriate interface on which to send packet */
  	if (!usipx->sipx_network && ipx_primary_net) {
  		usipx->sipx_network = ipx_primary_net->if_netnum;
  		intrfc = ipx_primary_net;
  	} else {
  		rt = ipxrtr_lookup(usipx->sipx_network);
  		rc = -ENETUNREACH;
  		if (!rt)
  			goto out;
  		intrfc = rt->ir_intrfc;
  	}
  
  	ipxitf_hold(intrfc);
  	ipx_offset = intrfc->if_ipx_offset;
  	size = sizeof(struct ipxhdr) + len + ipx_offset;
  
  	skb = sock_alloc_send_skb(sk, size, noblock, &rc);
  	if (!skb)
  		goto out_put;
  
  	skb_reserve(skb, ipx_offset);
  	skb->sk = sk;
  
  	/* Fill in IPX header */

  	skb_reset_network_header(skb);

  	skb_reset_transport_header(skb);

  	skb_put(skb, sizeof(struct ipxhdr));

  	ipx = ipx_hdr(skb);
  	ipx->ipx_pktsize = htons(len + sizeof(struct ipxhdr));
  	IPX_SKB_CB(skb)->ipx_tctrl = 0;
  	ipx->ipx_type 	 = usipx->sipx_type;
  
  	IPX_SKB_CB(skb)->last_hop.index = -1;
  #ifdef CONFIG_IPX_INTERN
  	IPX_SKB_CB(skb)->ipx_source_net = ipxs->intrfc->if_netnum;
  	memcpy(ipx->ipx_source.node, ipxs->node, IPX_NODE_LEN);
  #else
  	rc = ntohs(ipxs->port);
  	if (rc == 0x453 || rc == 0x452) {
  		/* RIP/SAP special handling for mars_nwe */
  		IPX_SKB_CB(skb)->ipx_source_net = intrfc->if_netnum;
  		memcpy(ipx->ipx_source.node, intrfc->if_node, IPX_NODE_LEN);
  	} else {
  		IPX_SKB_CB(skb)->ipx_source_net = ipxs->intrfc->if_netnum;
  		memcpy(ipx->ipx_source.node, ipxs->intrfc->if_node,
  			IPX_NODE_LEN);
  	}
  #endif	/* CONFIG_IPX_INTERN */
  	ipx->ipx_source.sock		= ipxs->port;
  	IPX_SKB_CB(skb)->ipx_dest_net	= usipx->sipx_network;
  	memcpy(ipx->ipx_dest.node, usipx->sipx_node, IPX_NODE_LEN);
  	ipx->ipx_dest.sock		= usipx->sipx_port;

  	rc = memcpy_from_msg(skb_put(skb, len), msg, len);

  	if (rc) {
  		kfree_skb(skb);
  		goto out_put;

  	}

  
  	/* Apply checksum. Not allowed on 802.3 links. */

  	if (sk->sk_no_check_tx ||
  	    intrfc->if_dlink_type == htons(IPX_FRAME_8023))

  		ipx->ipx_checksum = htons(0xFFFF);

  	else
  		ipx->ipx_checksum = ipx_cksum(ipx, len + sizeof(struct ipxhdr));

  	rc = ipxitf_send(intrfc, skb, (rt && rt->ir_routed) ?

  			 rt->ir_router_node : ipx->ipx_dest.node);
  out_put:
  	ipxitf_put(intrfc);
  	if (rt)
  		ipxrtr_put(rt);
  out:
  	return rc;
  }
  
  /*
   * We use a normal struct rtentry for route handling
   */
  int ipxrtr_ioctl(unsigned int cmd, void __user *arg)
  {
  	struct rtentry rt;	/* Use these to behave like 'other' stacks */
  	struct sockaddr_ipx *sg, *st;
  	int rc = -EFAULT;
  
  	if (copy_from_user(&rt, arg, sizeof(rt)))
  		goto out;
  
  	sg = (struct sockaddr_ipx *)&rt.rt_gateway;
  	st = (struct sockaddr_ipx *)&rt.rt_dst;
  
  	rc = -EINVAL;
  	if (!(rt.rt_flags & RTF_GATEWAY) || /* Direct routes are fixed */
  	    sg->sipx_family != AF_IPX ||
  	    st->sipx_family != AF_IPX)
  		goto out;
  
  	switch (cmd) {
  	case SIOCDELRT:
  		rc = ipxrtr_delete(st->sipx_network);
  		break;
  	case SIOCADDRT: {
  		struct ipx_route_definition f;
  		f.ipx_network		= st->sipx_network;
  		f.ipx_router_network	= sg->sipx_network;
  		memcpy(f.ipx_router_node, sg->sipx_node, IPX_NODE_LEN);
  		rc = ipxrtr_create(&f);
  		break;
  	}
  	}
  
  out:
  	return rc;
  }