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 kfree_skb(skb); 101 continue; 102 } 103 104 dev = rose_dev_get(dest); 105 if (!dev) { 106 kfree_skb(skb); 107 continue; 108 } 109 110 if (rose_rx_call_request(skb, dev, rose_loopback_neigh, lci_o) == 0) { 111 dev_put(dev); 112 kfree_skb(skb); 113 } 114 } else { 115 kfree_skb(skb); 116 } 117 } 118 if (!skb_queue_empty(&loopback_queue)) 119 mod_timer(&loopback_timer, jiffies + 1); 120 } 121 122 void __exit rose_loopback_clear(void) 123 { 124 struct sk_buff *skb; 125 126 del_timer(&loopback_timer); 127 128 while ((skb = skb_dequeue(&loopback_queue)) != NULL) { 129 skb->sk = NULL; 130 kfree_skb(skb); 131 } 132 } 133