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1275 |
phoenix |
/*
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* AX.25 release 037
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*
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* This code REQUIRES 2.1.15 or higher/ NET3.038
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*
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* This module:
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* This module is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Most of this code is based on the SDL diagrams published in the 7th
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* ARRL Computer Networking Conference papers. The diagrams have mistakes
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* in them, but are mostly correct. Before you modify the code could you
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* read the SDL diagrams as the code is not obvious and probably very
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* easy to break;
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*
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* History
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* AX.25 028a Jonathan(G4KLX) New state machine based on SDL diagrams.
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* AX.25 028b Jonathan(G4KLX) Extracted AX25 control block from
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* the sock structure.
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* AX.25 029 Alan(GW4PTS) Switched to KA9Q constant names.
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* Jonathan(G4KLX) Added IP mode registration.
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* AX.25 030 Jonathan(G4KLX) Added AX.25 fragment reception.
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* Upgraded state machine for SABME.
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* Added arbitrary protocol id support.
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* AX.25 031 Joerg(DL1BKE) Added DAMA support
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* HaJo(DD8NE) Added Idle Disc Timer T5
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* Joerg(DL1BKE) Renamed it to "IDLE" with a slightly
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* different behaviour. Fixed defrag
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* routine (I hope)
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* AX.25 032 Darryl(G7LED) AX.25 segmentation fixed.
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* AX.25 033 Jonathan(G4KLX) Remove auto-router.
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* Modularisation changes.
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* AX.25 035 Hans(PE1AYX) Fixed interface to IP layer.
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* AX.25 036 Jonathan(G4KLX) Move DAMA code into own file.
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* Joerg(DL1BKE) Fixed DAMA Slave.
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* AX.25 037 Jonathan(G4KLX) New timer architecture.
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* Thomas(DL9SAU) Fixed missing initialization of skb->protocol.
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*/
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#include <linux/config.h>
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#include <linux/errno.h>
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#include <linux/types.h>
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#include <linux/socket.h>
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#include <linux/in.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/timer.h>
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#include <linux/string.h>
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#include <linux/sockios.h>
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#include <linux/net.h>
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#include <net/ax25.h>
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#include <linux/inet.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/netfilter.h>
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#include <net/sock.h>
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#include <net/ip.h> /* For ip_rcv */
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#include <net/arp.h> /* For arp_rcv */
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <linux/fcntl.h>
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#include <linux/mm.h>
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#include <linux/interrupt.h>
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/*
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* Given a fragment, queue it on the fragment queue and if the fragment
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* is complete, send it back to ax25_rx_iframe.
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*/
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static int ax25_rx_fragment(ax25_cb *ax25, struct sk_buff *skb)
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{
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struct sk_buff *skbn, *skbo;
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if (ax25->fragno != 0) {
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if (!(*skb->data & AX25_SEG_FIRST)) {
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if ((ax25->fragno - 1) == (*skb->data & AX25_SEG_REM)) {
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/* Enqueue fragment */
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ax25->fragno = *skb->data & AX25_SEG_REM;
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skb_pull(skb, 1); /* skip fragno */
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ax25->fraglen += skb->len;
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skb_queue_tail(&ax25->frag_queue, skb);
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/* Last fragment received ? */
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if (ax25->fragno == 0) {
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skbn = alloc_skb(AX25_MAX_HEADER_LEN +
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ax25->fraglen,
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GFP_ATOMIC);
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if (!skbn) {
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skb_queue_purge(&ax25->frag_queue);
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return 1;
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}
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skb_reserve(skbn, AX25_MAX_HEADER_LEN);
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skbn->dev = ax25->ax25_dev->dev;
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skbn->h.raw = skbn->data;
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skbn->nh.raw = skbn->data;
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/* Copy data from the fragments */
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while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) {
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memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
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kfree_skb(skbo);
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}
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ax25->fraglen = 0;
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if (ax25_rx_iframe(ax25, skbn) == 0)
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kfree_skb(skbn);
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}
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return 1;
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}
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}
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} else {
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/* First fragment received */
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if (*skb->data & AX25_SEG_FIRST) {
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skb_queue_purge(&ax25->frag_queue);
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ax25->fragno = *skb->data & AX25_SEG_REM;
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skb_pull(skb, 1); /* skip fragno */
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ax25->fraglen = skb->len;
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skb_queue_tail(&ax25->frag_queue, skb);
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return 1;
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}
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}
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return 0;
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}
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/*
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* This is where all valid I frames are sent to, to be dispatched to
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* whichever protocol requires them.
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*/
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int ax25_rx_iframe(ax25_cb *ax25, struct sk_buff *skb)
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{
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int (*func)(struct sk_buff *, ax25_cb *);
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volatile int queued = 0;
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unsigned char pid;
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if (skb == NULL) return 0;
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ax25_start_idletimer(ax25);
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pid = *skb->data;
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#ifdef CONFIG_INET
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if (pid == AX25_P_IP) {
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/* working around a TCP bug to keep additional listeners
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* happy. TCP re-uses the buffer and destroys the original
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* content.
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*/
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struct sk_buff *skbn = skb_copy(skb, GFP_ATOMIC);
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if (skbn != NULL) {
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kfree_skb(skb);
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skb = skbn;
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}
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skb_pull(skb, 1); /* Remove PID */
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skb->h.raw = skb->data;
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skb->nh.raw = skb->data;
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skb->dev = ax25->ax25_dev->dev;
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skb->pkt_type = PACKET_HOST;
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skb->protocol = htons(ETH_P_IP);
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ip_rcv(skb, skb->dev, NULL); /* Wrong ptype */
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return 1;
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}
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#endif
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if (pid == AX25_P_SEGMENT) {
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skb_pull(skb, 1); /* Remove PID */
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return ax25_rx_fragment(ax25, skb);
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}
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if ((func = ax25_protocol_function(pid)) != NULL) {
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skb_pull(skb, 1); /* Remove PID */
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return (*func)(skb, ax25);
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}
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| 178 |
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if (ax25->sk != NULL && ax25->ax25_dev->values[AX25_VALUES_CONMODE] == 2) {
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if ((!ax25->pidincl && ax25->sk->protocol == pid) || ax25->pidincl) {
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if (sock_queue_rcv_skb(ax25->sk, skb) == 0)
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queued = 1;
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else
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ax25->condition |= AX25_COND_OWN_RX_BUSY;
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}
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}
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| 187 |
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return queued;
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}
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| 189 |
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| 190 |
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/*
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* Higher level upcall for a LAPB frame
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*/
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static int ax25_process_rx_frame(ax25_cb *ax25, struct sk_buff *skb, int type, int dama)
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{
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| 195 |
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int queued = 0;
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| 196 |
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| 197 |
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if (ax25->state == AX25_STATE_0)
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| 198 |
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return 0;
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| 199 |
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| 200 |
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switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
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case AX25_PROTO_STD_SIMPLEX:
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case AX25_PROTO_STD_DUPLEX:
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queued = ax25_std_frame_in(ax25, skb, type);
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break;
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| 206 |
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#ifdef CONFIG_AX25_DAMA_SLAVE
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case AX25_PROTO_DAMA_SLAVE:
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if (dama || ax25->ax25_dev->dama.slave)
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queued = ax25_ds_frame_in(ax25, skb, type);
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else
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queued = ax25_std_frame_in(ax25, skb, type);
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break;
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#endif
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}
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| 216 |
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return queued;
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| 217 |
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}
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| 218 |
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| 219 |
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static int ax25_rcv(struct sk_buff *skb, struct net_device *dev, ax25_address *dev_addr, struct packet_type *ptype)
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| 220 |
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{
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| 221 |
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struct sock *make;
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| 222 |
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struct sock *sk;
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| 223 |
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int type = 0;
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| 224 |
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ax25_digi dp, reverse_dp;
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| 225 |
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ax25_cb *ax25;
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| 226 |
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ax25_address src, dest;
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| 227 |
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ax25_address *next_digi = NULL;
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| 228 |
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ax25_dev *ax25_dev;
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| 229 |
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struct sock *raw;
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| 230 |
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int mine = 0;
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| 231 |
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int dama;
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| 232 |
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| 233 |
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/*
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| 234 |
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* Process the AX.25/LAPB frame.
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| 235 |
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*/
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| 237 |
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skb->h.raw = skb->data;
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| 238 |
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| 239 |
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if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) {
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| 240 |
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kfree_skb(skb);
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| 241 |
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return 0;
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| 242 |
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}
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| 243 |
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| 244 |
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/*
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| 245 |
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* Parse the address header.
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| 246 |
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*/
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| 247 |
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| 248 |
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if (ax25_addr_parse(skb->data, skb->len, &src, &dest, &dp, &type, &dama) == NULL) {
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| 249 |
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kfree_skb(skb);
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| 250 |
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return 0;
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| 251 |
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}
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| 252 |
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| 253 |
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/*
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| 254 |
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* Ours perhaps ?
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| 255 |
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*/
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| 256 |
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if (dp.lastrepeat + 1 < dp.ndigi) /* Not yet digipeated completely */
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| 257 |
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next_digi = &dp.calls[dp.lastrepeat + 1];
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| 258 |
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| 259 |
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/*
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| 260 |
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* Pull of the AX.25 headers leaving the CTRL/PID bytes
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| 261 |
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*/
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| 262 |
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skb_pull(skb, ax25_addr_size(&dp));
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| 263 |
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| 264 |
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/* For our port addresses ? */
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| 265 |
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if (ax25cmp(&dest, dev_addr) == 0 && dp.lastrepeat + 1 == dp.ndigi)
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| 266 |
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mine = 1;
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| 267 |
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| 268 |
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/* Also match on any registered callsign from L3/4 */
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| 269 |
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if (!mine && ax25_listen_mine(&dest, dev) && dp.lastrepeat + 1 == dp.ndigi)
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| 270 |
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mine = 1;
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| 271 |
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| 272 |
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/* UI frame - bypass LAPB processing */
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| 273 |
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if ((*skb->data & ~0x10) == AX25_UI && dp.lastrepeat + 1 == dp.ndigi) {
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| 274 |
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skb->h.raw = skb->data + 2; /* skip control and pid */
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| 275 |
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|
| 276 |
|
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if ((raw = ax25_addr_match(&dest)) != NULL)
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| 277 |
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ax25_send_to_raw(raw, skb, skb->data[1]);
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| 278 |
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|
| 279 |
|
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if (!mine && ax25cmp(&dest, (ax25_address *)dev->broadcast) != 0) {
|
| 280 |
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kfree_skb(skb);
|
| 281 |
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return 0;
|
| 282 |
|
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}
|
| 283 |
|
|
|
| 284 |
|
|
/* Now we are pointing at the pid byte */
|
| 285 |
|
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switch (skb->data[1]) {
|
| 286 |
|
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#ifdef CONFIG_INET
|
| 287 |
|
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case AX25_P_IP:
|
| 288 |
|
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skb_pull(skb,2); /* drop PID/CTRL */
|
| 289 |
|
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skb->h.raw = skb->data;
|
| 290 |
|
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skb->nh.raw = skb->data;
|
| 291 |
|
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skb->dev = dev;
|
| 292 |
|
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skb->pkt_type = PACKET_HOST;
|
| 293 |
|
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skb->protocol = htons(ETH_P_IP);
|
| 294 |
|
|
ip_rcv(skb, dev, ptype); /* Note ptype here is the wrong one, fix me later */
|
| 295 |
|
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break;
|
| 296 |
|
|
|
| 297 |
|
|
case AX25_P_ARP:
|
| 298 |
|
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skb_pull(skb,2);
|
| 299 |
|
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skb->h.raw = skb->data;
|
| 300 |
|
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skb->nh.raw = skb->data;
|
| 301 |
|
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skb->dev = dev;
|
| 302 |
|
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skb->pkt_type = PACKET_HOST;
|
| 303 |
|
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skb->protocol = htons(ETH_P_ARP);
|
| 304 |
|
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arp_rcv(skb, dev, ptype); /* Note ptype here is wrong... */
|
| 305 |
|
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break;
|
| 306 |
|
|
#endif
|
| 307 |
|
|
case AX25_P_TEXT:
|
| 308 |
|
|
/* Now find a suitable dgram socket */
|
| 309 |
|
|
if ((sk = ax25_find_socket(&dest, &src, SOCK_DGRAM)) != NULL) {
|
| 310 |
|
|
if (atomic_read(&sk->rmem_alloc) >= sk->rcvbuf) {
|
| 311 |
|
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kfree_skb(skb);
|
| 312 |
|
|
} else {
|
| 313 |
|
|
/*
|
| 314 |
|
|
* Remove the control and PID.
|
| 315 |
|
|
*/
|
| 316 |
|
|
skb_pull(skb, 2);
|
| 317 |
|
|
if (sock_queue_rcv_skb(sk, skb) != 0)
|
| 318 |
|
|
kfree_skb(skb);
|
| 319 |
|
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}
|
| 320 |
|
|
} else {
|
| 321 |
|
|
kfree_skb(skb);
|
| 322 |
|
|
}
|
| 323 |
|
|
break;
|
| 324 |
|
|
|
| 325 |
|
|
default:
|
| 326 |
|
|
kfree_skb(skb); /* Will scan SOCK_AX25 RAW sockets */
|
| 327 |
|
|
break;
|
| 328 |
|
|
}
|
| 329 |
|
|
|
| 330 |
|
|
return 0;
|
| 331 |
|
|
}
|
| 332 |
|
|
|
| 333 |
|
|
/*
|
| 334 |
|
|
* Is connected mode supported on this device ?
|
| 335 |
|
|
* If not, should we DM the incoming frame (except DMs) or
|
| 336 |
|
|
* silently ignore them. For now we stay quiet.
|
| 337 |
|
|
*/
|
| 338 |
|
|
if (ax25_dev->values[AX25_VALUES_CONMODE] == 0) {
|
| 339 |
|
|
kfree_skb(skb);
|
| 340 |
|
|
return 0;
|
| 341 |
|
|
}
|
| 342 |
|
|
|
| 343 |
|
|
/* LAPB */
|
| 344 |
|
|
|
| 345 |
|
|
/* AX.25 state 1-4 */
|
| 346 |
|
|
|
| 347 |
|
|
ax25_digi_invert(&dp, &reverse_dp);
|
| 348 |
|
|
|
| 349 |
|
|
if ((ax25 = ax25_find_cb(&dest, &src, &reverse_dp, dev)) != NULL) {
|
| 350 |
|
|
/*
|
| 351 |
|
|
* Process the frame. If it is queued up internally it returns one otherwise we
|
| 352 |
|
|
* free it immediately. This routine itself wakes the user context layers so we
|
| 353 |
|
|
* do no further work
|
| 354 |
|
|
*/
|
| 355 |
|
|
if (ax25_process_rx_frame(ax25, skb, type, dama) == 0)
|
| 356 |
|
|
kfree_skb(skb);
|
| 357 |
|
|
|
| 358 |
|
|
return 0;
|
| 359 |
|
|
}
|
| 360 |
|
|
|
| 361 |
|
|
/* AX.25 state 0 (disconnected) */
|
| 362 |
|
|
|
| 363 |
|
|
/* a) received not a SABM(E) */
|
| 364 |
|
|
|
| 365 |
|
|
if ((*skb->data & ~AX25_PF) != AX25_SABM && (*skb->data & ~AX25_PF) != AX25_SABME) {
|
| 366 |
|
|
/*
|
| 367 |
|
|
* Never reply to a DM. Also ignore any connects for
|
| 368 |
|
|
* addresses that are not our interfaces and not a socket.
|
| 369 |
|
|
*/
|
| 370 |
|
|
if ((*skb->data & ~AX25_PF) != AX25_DM && mine)
|
| 371 |
|
|
ax25_return_dm(dev, &src, &dest, &dp);
|
| 372 |
|
|
|
| 373 |
|
|
kfree_skb(skb);
|
| 374 |
|
|
return 0;
|
| 375 |
|
|
}
|
| 376 |
|
|
|
| 377 |
|
|
/* b) received SABM(E) */
|
| 378 |
|
|
|
| 379 |
|
|
if (dp.lastrepeat + 1 == dp.ndigi)
|
| 380 |
|
|
sk = ax25_find_listener(&dest, 0, dev, SOCK_SEQPACKET);
|
| 381 |
|
|
else
|
| 382 |
|
|
sk = ax25_find_listener(next_digi, 1, dev, SOCK_SEQPACKET);
|
| 383 |
|
|
|
| 384 |
|
|
if (sk != NULL) {
|
| 385 |
|
|
if (sk->ack_backlog == sk->max_ack_backlog || (make = ax25_make_new(sk, ax25_dev)) == NULL) {
|
| 386 |
|
|
if (mine) ax25_return_dm(dev, &src, &dest, &dp);
|
| 387 |
|
|
kfree_skb(skb);
|
| 388 |
|
|
return 0;
|
| 389 |
|
|
}
|
| 390 |
|
|
|
| 391 |
|
|
ax25 = make->protinfo.ax25;
|
| 392 |
|
|
skb_set_owner_r(skb, make);
|
| 393 |
|
|
skb_queue_head(&sk->receive_queue, skb);
|
| 394 |
|
|
|
| 395 |
|
|
make->state = TCP_ESTABLISHED;
|
| 396 |
|
|
make->pair = sk;
|
| 397 |
|
|
|
| 398 |
|
|
sk->ack_backlog++;
|
| 399 |
|
|
} else {
|
| 400 |
|
|
if (!mine) {
|
| 401 |
|
|
kfree_skb(skb);
|
| 402 |
|
|
return 0;
|
| 403 |
|
|
}
|
| 404 |
|
|
|
| 405 |
|
|
if ((ax25 = ax25_create_cb()) == NULL) {
|
| 406 |
|
|
ax25_return_dm(dev, &src, &dest, &dp);
|
| 407 |
|
|
kfree_skb(skb);
|
| 408 |
|
|
return 0;
|
| 409 |
|
|
}
|
| 410 |
|
|
|
| 411 |
|
|
ax25_fillin_cb(ax25, ax25_dev);
|
| 412 |
|
|
}
|
| 413 |
|
|
|
| 414 |
|
|
ax25->source_addr = dest;
|
| 415 |
|
|
ax25->dest_addr = src;
|
| 416 |
|
|
|
| 417 |
|
|
/*
|
| 418 |
|
|
* Sort out any digipeated paths.
|
| 419 |
|
|
*/
|
| 420 |
|
|
if (dp.ndigi && !ax25->digipeat &&
|
| 421 |
|
|
(ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
|
| 422 |
|
|
kfree_skb(skb);
|
| 423 |
|
|
ax25_destroy_socket(ax25);
|
| 424 |
|
|
return 0;
|
| 425 |
|
|
}
|
| 426 |
|
|
|
| 427 |
|
|
if (dp.ndigi == 0) {
|
| 428 |
|
|
if (ax25->digipeat != NULL) {
|
| 429 |
|
|
kfree(ax25->digipeat);
|
| 430 |
|
|
ax25->digipeat = NULL;
|
| 431 |
|
|
}
|
| 432 |
|
|
} else {
|
| 433 |
|
|
/* Reverse the source SABM's path */
|
| 434 |
|
|
memcpy(ax25->digipeat, &reverse_dp, sizeof(ax25_digi));
|
| 435 |
|
|
}
|
| 436 |
|
|
|
| 437 |
|
|
if ((*skb->data & ~AX25_PF) == AX25_SABME) {
|
| 438 |
|
|
ax25->modulus = AX25_EMODULUS;
|
| 439 |
|
|
ax25->window = ax25_dev->values[AX25_VALUES_EWINDOW];
|
| 440 |
|
|
} else {
|
| 441 |
|
|
ax25->modulus = AX25_MODULUS;
|
| 442 |
|
|
ax25->window = ax25_dev->values[AX25_VALUES_WINDOW];
|
| 443 |
|
|
}
|
| 444 |
|
|
|
| 445 |
|
|
ax25_send_control(ax25, AX25_UA, AX25_POLLON, AX25_RESPONSE);
|
| 446 |
|
|
|
| 447 |
|
|
#ifdef CONFIG_AX25_DAMA_SLAVE
|
| 448 |
|
|
if (dama && ax25->ax25_dev->values[AX25_VALUES_PROTOCOL] == AX25_PROTO_DAMA_SLAVE)
|
| 449 |
|
|
ax25_dama_on(ax25);
|
| 450 |
|
|
#endif
|
| 451 |
|
|
|
| 452 |
|
|
ax25->state = AX25_STATE_3;
|
| 453 |
|
|
|
| 454 |
|
|
ax25_insert_socket(ax25);
|
| 455 |
|
|
|
| 456 |
|
|
ax25_start_heartbeat(ax25);
|
| 457 |
|
|
ax25_start_t3timer(ax25);
|
| 458 |
|
|
ax25_start_idletimer(ax25);
|
| 459 |
|
|
|
| 460 |
|
|
if (sk != NULL) {
|
| 461 |
|
|
if (!sk->dead)
|
| 462 |
|
|
sk->data_ready(sk, skb->len);
|
| 463 |
|
|
} else {
|
| 464 |
|
|
kfree_skb(skb);
|
| 465 |
|
|
}
|
| 466 |
|
|
|
| 467 |
|
|
return 0;
|
| 468 |
|
|
}
|
| 469 |
|
|
|
| 470 |
|
|
/*
|
| 471 |
|
|
* Receive an AX.25 frame via a SLIP interface.
|
| 472 |
|
|
*/
|
| 473 |
|
|
int ax25_kiss_rcv(struct sk_buff *skb, struct net_device *dev,
|
| 474 |
|
|
struct packet_type *ptype)
|
| 475 |
|
|
{
|
| 476 |
|
|
skb->sk = NULL; /* Initially we don't know who it's for */
|
| 477 |
|
|
skb->destructor = NULL; /* Who initializes this, dammit?! */
|
| 478 |
|
|
|
| 479 |
|
|
if ((*skb->data & 0x0F) != 0) {
|
| 480 |
|
|
kfree_skb(skb); /* Not a KISS data frame */
|
| 481 |
|
|
return 0;
|
| 482 |
|
|
}
|
| 483 |
|
|
|
| 484 |
|
|
skb_pull(skb, AX25_KISS_HEADER_LEN); /* Remove the KISS byte */
|
| 485 |
|
|
|
| 486 |
|
|
return ax25_rcv(skb, dev, (ax25_address *)dev->dev_addr, ptype);
|
| 487 |
|
|
}
|
| 488 |
|
|
|
