net/rose/rose_loopback.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *
   4  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   5  */
   6 #include <linux/types.h>
   7 #include <linux/slab.h>
   8 #include <linux/socket.h>
   9 #include <linux/timer.h>
  10 #include <net/ax25.h>
  11 #include <linux/skbuff.h>
  12 #include <net/rose.h>
  13 #include <linux/init.h>
  14
  15 static struct sk_buff_head loopback_queue;
  16 #define ROSE_LOOPBACK_LIMIT 1000
  17 static struct timer_list loopback_timer;
  18
  19 static void rose_set_loopback_timer(void);
  20 static void rose_loopback_timer(struct timer_list *unused);
  21
  22 void rose_loopback_init(void)
  23 {
  24         skb_queue_head_init(&loopback_queue);
  25
  26         timer_setup(&loopback_timer, rose_loopback_timer, 0);
  27 }
  28
  29 static int rose_loopback_running(void)
  30 {
  31         return timer_pending(&loopback_timer);
  32 }
  33
  34 int rose_loopback_queue(struct sk_buff *skb, struct rose_neigh *neigh)
  35 {
  36         struct sk_buff *skbn = NULL;
  37
  38         if (skb_queue_len(&loopback_queue) < ROSE_LOOPBACK_LIMIT)
  39                 skbn = skb_clone(skb, GFP_ATOMIC);
  40
  41         if (skbn) {
  42                 consume_skb(skb);
  43                 skb_queue_tail(&loopback_queue, skbn);
  44
  45                 if (!rose_loopback_running())
  46                         rose_set_loopback_timer();
  47         } else {
  48                 kfree_skb(skb);
  49         }
  50
  51         return 1;
  52 }
  53
  54 static void rose_set_loopback_timer(void)
  55 {
  56         mod_timer(&loopback_timer, jiffies + 10);
  57 }
  58
  59 static void rose_loopback_timer(struct timer_list *unused)
  60 {
  61         struct sk_buff *skb;
  62         struct net_device *dev;
  63         rose_address *dest;
  64         struct sock *sk;
  65         unsigned short frametype;
  66         unsigned int lci_i, lci_o;
  67         int count;
  68
  69         for (count = 0; count < ROSE_LOOPBACK_LIMIT; count++) {
  70                 skb = skb_dequeue(&loopback_queue);
  71                 if (!skb)
  72                         return;
  73                 if (skb->len < ROSE_MIN_LEN) {
  74                         kfree_skb(skb);
  75                         continue;
  76                 }
  77                 lci_i     = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
  78                 frametype = skb->data[2];
  79                 if (frametype == ROSE_CALL_REQUEST &&
  80                     (skb->len <= ROSE_CALL_REQ_FACILITIES_OFF ||
  81                      skb->data[ROSE_CALL_REQ_ADDR_LEN_OFF] !=
  82                      ROSE_CALL_REQ_ADDR_LEN_VAL)) {
  83                         kfree_skb(skb);
  84                         continue;
  85                 }
  86                 dest      = (rose_address *)(skb->data + ROSE_CALL_REQ_DEST_ADDR_OFF);
  87                 lci_o     = ROSE_DEFAULT_MAXVC + 1 - lci_i;
  88
  89                 skb_reset_transport_header(skb);
  90
  91                 sk = rose_find_socket(lci_o, rose_loopback_neigh);
  92                 if (sk) {
  93                         if (rose_process_rx_frame(sk, skb) == 0)
  94                                 kfree_skb(skb);
  95                         continue;
  96                 }
  97
  98                 if (frametype == ROSE_CALL_REQUEST) {
  99                         if (!rose_loopback_neigh->dev &&
 100                             !rose_loopback_neigh->loopback) {
 101                                 kfree_skb(skb);
 102                                 continue;
 103                         }
 104
 105                         dev = rose_dev_get(dest);
 106                         if (!dev) {
 107                                 kfree_skb(skb);
 108                                 continue;
 109                         }
 110
 111                         if (rose_rx_call_request(skb, dev, rose_loopback_neigh, lci_o) == 0) {
 112                                 dev_put(dev);
 113                                 kfree_skb(skb);
 114                         }
 115                 } else {
 116                         kfree_skb(skb);
 117                 }
 118         }
 119         if (!skb_queue_empty(&loopback_queue))
 120                 mod_timer(&loopback_timer, jiffies + 1);
 121 }
 122
 123 void __exit rose_loopback_clear(void)
 124 {
 125         struct sk_buff *skb;
 126
 127         del_timer(&loopback_timer);
 128
 129         while ((skb = skb_dequeue(&loopback_queue)) != NULL) {
 130                 skb->sk = NULL;
 131                 kfree_skb(skb);
 132         }
 133 }