net/rose/rose_loopback.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License as published by
   4  * the Free Software Foundation; either version 2 of the License, or
   5  * (at your option) any later version.
   6  *
   7  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   8  */
   9 #include <linux/types.h>
  10 #include <linux/slab.h>
  11 #include <linux/socket.h>
  12 #include <linux/timer.h>
  13 #include <net/ax25.h>
  14 #include <linux/skbuff.h>
  15 #include <net/rose.h>
  16 #include <linux/init.h>
  17
  18 static struct sk_buff_head loopback_queue;
  19 #define ROSE_LOOPBACK_LIMIT 1000
  20 static struct timer_list loopback_timer;
  21
  22 static void rose_set_loopback_timer(void);
  23 static void rose_loopback_timer(struct timer_list *unused);
  24
  25 void rose_loopback_init(void)
  26 {
  27         skb_queue_head_init(&loopback_queue);
  28
  29         timer_setup(&loopback_timer, rose_loopback_timer, 0);
  30 }
  31
  32 static int rose_loopback_running(void)
  33 {
  34         return timer_pending(&loopback_timer);
  35 }
  36
  37 int rose_loopback_queue(struct sk_buff *skb, struct rose_neigh *neigh)
  38 {
  39         struct sk_buff *skbn = NULL;
  40
  41         if (skb_queue_len(&loopback_queue) < ROSE_LOOPBACK_LIMIT)
  42                 skbn = skb_clone(skb, GFP_ATOMIC);
  43
  44         if (skbn) {
  45                 consume_skb(skb);
  46                 skb_queue_tail(&loopback_queue, skbn);
  47
  48                 if (!rose_loopback_running())
  49                         rose_set_loopback_timer();
  50         } else {
  51                 kfree_skb(skb);
  52         }
  53
  54         return 1;
  55 }
  56
  57 static void rose_set_loopback_timer(void)
  58 {
  59         mod_timer(&loopback_timer, jiffies + 10);
  60 }
  61
  62 static void rose_loopback_timer(struct timer_list *unused)
  63 {
  64         struct sk_buff *skb;
  65         struct net_device *dev;
  66         rose_address *dest;
  67         struct sock *sk;
  68         unsigned short frametype;
  69         unsigned int lci_i, lci_o;
  70         int count;
  71
  72         for (count = 0; count < ROSE_LOOPBACK_LIMIT; count++) {
  73                 skb = skb_dequeue(&loopback_queue);
  74                 if (!skb)
  75                         return;
  76                 if (skb->len < ROSE_MIN_LEN) {
  77                         kfree_skb(skb);
  78                         continue;
  79                 }
  80                 lci_i     = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
  81                 frametype = skb->data[2];
  82                 if (frametype == ROSE_CALL_REQUEST &&
  83                     (skb->len <= ROSE_CALL_REQ_FACILITIES_OFF ||
  84                      skb->data[ROSE_CALL_REQ_ADDR_LEN_OFF] !=
  85                      ROSE_CALL_REQ_ADDR_LEN_VAL)) {
  86                         kfree_skb(skb);
  87                         continue;
  88                 }
  89                 dest      = (rose_address *)(skb->data + ROSE_CALL_REQ_DEST_ADDR_OFF);
  90                 lci_o     = ROSE_DEFAULT_MAXVC + 1 - lci_i;
  91
  92                 skb_reset_transport_header(skb);
  93
  94                 sk = rose_find_socket(lci_o, rose_loopback_neigh);
  95                 if (sk) {
  96                         if (rose_process_rx_frame(sk, skb) == 0)
  97                                 kfree_skb(skb);
  98                         continue;
  99                 }
 100
 101                 if (frametype == ROSE_CALL_REQUEST) {
 102                         if ((dev = rose_dev_get(dest)) != NULL) {
 103                                 if (rose_rx_call_request(skb, dev, rose_loopback_neigh, lci_o) == 0)
 104                                         kfree_skb(skb);
 105                         } else {
 106                                 kfree_skb(skb);
 107                         }
 108                 } else {
 109                         kfree_skb(skb);
 110                 }
 111         }
 112         if (!skb_queue_empty(&loopback_queue))
 113                 mod_timer(&loopback_timer, jiffies + 1);
 114 }
 115
 116 void __exit rose_loopback_clear(void)
 117 {
 118         struct sk_buff *skb;
 119
 120         del_timer(&loopback_timer);
 121
 122         while ((skb = skb_dequeue(&loopback_queue)) != NULL) {
 123                 skb->sk = NULL;
 124                 kfree_skb(skb);
 125         }
 126 }