net/rose/rose_loopback.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  *
0004  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
0005  */
0006 #include <linux/types.h>
0007 #include <linux/slab.h>
0008 #include <linux/socket.h>
0009 #include <linux/timer.h>
0010 #include <net/ax25.h>
0011 #include <linux/skbuff.h>
0012 #include <net/rose.h>
0013 #include <linux/init.h>
0014
0015 static struct sk_buff_head loopback_queue;
0016 #define ROSE_LOOPBACK_LIMIT 1000
0017 static struct timer_list loopback_timer;
0018
0019 static void rose_set_loopback_timer(void);
0020 static void rose_loopback_timer(struct timer_list *unused);
0021
0022 void rose_loopback_init(void)
0023 {
0024     skb_queue_head_init(&loopback_queue);
0025
0026     timer_setup(&loopback_timer, rose_loopback_timer, 0);
0027 }
0028
0029 static int rose_loopback_running(void)
0030 {
0031     return timer_pending(&loopback_timer);
0032 }
0033
0034 int rose_loopback_queue(struct sk_buff *skb, struct rose_neigh *neigh)
0035 {
0036     struct sk_buff *skbn = NULL;
0037
0038     if (skb_queue_len(&loopback_queue) < ROSE_LOOPBACK_LIMIT)
0039         skbn = skb_clone(skb, GFP_ATOMIC);
0040
0041     if (skbn) {
0042         consume_skb(skb);
0043         skb_queue_tail(&loopback_queue, skbn);
0044
0045         if (!rose_loopback_running())
0046             rose_set_loopback_timer();
0047     } else {
0048         kfree_skb(skb);
0049     }
0050
0051     return 1;
0052 }
0053
0054 static void rose_set_loopback_timer(void)
0055 {
0056     mod_timer(&loopback_timer, jiffies + 10);
0057 }
0058
0059 static void rose_loopback_timer(struct timer_list *unused)
0060 {
0061     struct sk_buff *skb;
0062     struct net_device *dev;
0063     rose_address *dest;
0064     struct sock *sk;
0065     unsigned short frametype;
0066     unsigned int lci_i, lci_o;
0067     int count;
0068
0069     for (count = 0; count < ROSE_LOOPBACK_LIMIT; count++) {
0070         skb = skb_dequeue(&loopback_queue);
0071         if (!skb)
0072             return;
0073         if (skb->len < ROSE_MIN_LEN) {
0074             kfree_skb(skb);
0075             continue;
0076         }
0077         lci_i     = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
0078         frametype = skb->data[2];
0079         if (frametype == ROSE_CALL_REQUEST &&
0080             (skb->len <= ROSE_CALL_REQ_FACILITIES_OFF ||
0081              skb->data[ROSE_CALL_REQ_ADDR_LEN_OFF] !=
0082              ROSE_CALL_REQ_ADDR_LEN_VAL)) {
0083             kfree_skb(skb);
0084             continue;
0085         }
0086         dest      = (rose_address *)(skb->data + ROSE_CALL_REQ_DEST_ADDR_OFF);
0087         lci_o     = ROSE_DEFAULT_MAXVC + 1 - lci_i;
0088
0089         skb_reset_transport_header(skb);
0090
0091         sk = rose_find_socket(lci_o, rose_loopback_neigh);
0092         if (sk) {
0093             if (rose_process_rx_frame(sk, skb) == 0)
0094                 kfree_skb(skb);
0095             continue;
0096         }
0097
0098         if (frametype == ROSE_CALL_REQUEST) {
0099             if (!rose_loopback_neigh->dev &&
0100                 !rose_loopback_neigh->loopback) {
0101                 kfree_skb(skb);
0102                 continue;
0103             }
0104
0105             dev = rose_dev_get(dest);
0106             if (!dev) {
0107                 kfree_skb(skb);
0108                 continue;
0109             }
0110
0111             if (rose_rx_call_request(skb, dev, rose_loopback_neigh, lci_o) == 0) {
0112                 dev_put(dev);
0113                 kfree_skb(skb);
0114             }
0115         } else {
0116             kfree_skb(skb);
0117         }
0118     }
0119     if (!skb_queue_empty(&loopback_queue))
0120         mod_timer(&loopback_timer, jiffies + 1);
0121 }
0122
0123 void __exit rose_loopback_clear(void)
0124 {
0125     struct sk_buff *skb;
0126
0127     del_timer(&loopback_timer);
0128
0129     while ((skb = skb_dequeue(&loopback_queue)) != NULL) {
0130         skb->sk = NULL;
0131         kfree_skb(skb);
0132     }
0133 }