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- /*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
- * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
- * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
- * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de)
- */
- #include <linux/errno.h>
- #include <linux/types.h>
- #include <linux/socket.h>
- #include <linux/in.h>
- #include <linux/kernel.h>
- #include <linux/timer.h>
- #include <linux/string.h>
- #include <linux/sockios.h>
- #include <linux/net.h>
- #include <linux/slab.h>
- #include <net/ax25.h>
- #include <linux/inet.h>
- #include <linux/netdevice.h>
- #include <linux/skbuff.h>
- #include <linux/netfilter.h>
- #include <net/sock.h>
- #include <net/tcp_states.h>
- #include <asm/uaccess.h>
- #include <asm/system.h>
- #include <linux/fcntl.h>
- #include <linux/mm.h>
- #include <linux/interrupt.h>
- /*
- * Given a fragment, queue it on the fragment queue and if the fragment
- * is complete, send it back to ax25_rx_iframe.
- */
- static int ax25_rx_fragment(ax25_cb *ax25, struct sk_buff *skb)
- {
- struct sk_buff *skbn, *skbo;
- if (ax25->fragno != 0) {
- if (!(*skb->data & AX25_SEG_FIRST)) {
- if ((ax25->fragno - 1) == (*skb->data & AX25_SEG_REM)) {
- /* Enqueue fragment */
- ax25->fragno = *skb->data & AX25_SEG_REM;
- skb_pull(skb, 1); /* skip fragno */
- ax25->fraglen += skb->len;
- skb_queue_tail(&ax25->frag_queue, skb);
- /* Last fragment received ? */
- if (ax25->fragno == 0) {
- skbn = alloc_skb(AX25_MAX_HEADER_LEN +
- ax25->fraglen,
- GFP_ATOMIC);
- if (!skbn) {
- skb_queue_purge(&ax25->frag_queue);
- return 1;
- }
- skb_reserve(skbn, AX25_MAX_HEADER_LEN);
- skbn->dev = ax25->ax25_dev->dev;
- skb_reset_network_header(skbn);
- skb_reset_transport_header(skbn);
- /* Copy data from the fragments */
- while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) {
- skb_copy_from_linear_data(skbo,
- skb_put(skbn, skbo->len),
- skbo->len);
- kfree_skb(skbo);
- }
- ax25->fraglen = 0;
- if (ax25_rx_iframe(ax25, skbn) == 0)
- kfree_skb(skbn);
- }
- return 1;
- }
- }
- } else {
- /* First fragment received */
- if (*skb->data & AX25_SEG_FIRST) {
- skb_queue_purge(&ax25->frag_queue);
- ax25->fragno = *skb->data & AX25_SEG_REM;
- skb_pull(skb, 1); /* skip fragno */
- ax25->fraglen = skb->len;
- skb_queue_tail(&ax25->frag_queue, skb);
- return 1;
- }
- }
- return 0;
- }
- /*
- * This is where all valid I frames are sent to, to be dispatched to
- * whichever protocol requires them.
- */
- int ax25_rx_iframe(ax25_cb *ax25, struct sk_buff *skb)
- {
- int (*func)(struct sk_buff *, ax25_cb *);
- unsigned char pid;
- int queued = 0;
- if (skb == NULL) return 0;
- ax25_start_idletimer(ax25);
- pid = *skb->data;
- if (pid == AX25_P_IP) {
- /* working around a TCP bug to keep additional listeners
- * happy. TCP re-uses the buffer and destroys the original
- * content.
- */
- struct sk_buff *skbn = skb_copy(skb, GFP_ATOMIC);
- if (skbn != NULL) {
- kfree_skb(skb);
- skb = skbn;
- }
- skb_pull(skb, 1); /* Remove PID */
- skb->mac_header = skb->network_header;
- skb_reset_network_header(skb);
- skb->dev = ax25->ax25_dev->dev;
- skb->pkt_type = PACKET_HOST;
- skb->protocol = htons(ETH_P_IP);
- netif_rx(skb);
- return 1;
- }
- if (pid == AX25_P_SEGMENT) {
- skb_pull(skb, 1); /* Remove PID */
- return ax25_rx_fragment(ax25, skb);
- }
- if ((func = ax25_protocol_function(pid)) != NULL) {
- skb_pull(skb, 1); /* Remove PID */
- return (*func)(skb, ax25);
- }
- if (ax25->sk != NULL && ax25->ax25_dev->values[AX25_VALUES_CONMODE] == 2) {
- if ((!ax25->pidincl && ax25->sk->sk_protocol == pid) ||
- ax25->pidincl) {
- if (sock_queue_rcv_skb(ax25->sk, skb) == 0)
- queued = 1;
- else
- ax25->condition |= AX25_COND_OWN_RX_BUSY;
- }
- }
- return queued;
- }
- /*
- * Higher level upcall for a LAPB frame
- */
- static int ax25_process_rx_frame(ax25_cb *ax25, struct sk_buff *skb, int type, int dama)
- {
- int queued = 0;
- if (ax25->state == AX25_STATE_0)
- return 0;
- switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
- case AX25_PROTO_STD_SIMPLEX:
- case AX25_PROTO_STD_DUPLEX:
- queued = ax25_std_frame_in(ax25, skb, type);
- break;
- #ifdef CONFIG_AX25_DAMA_SLAVE
- case AX25_PROTO_DAMA_SLAVE:
- if (dama || ax25->ax25_dev->dama.slave)
- queued = ax25_ds_frame_in(ax25, skb, type);
- else
- queued = ax25_std_frame_in(ax25, skb, type);
- break;
- #endif
- }
- return queued;
- }
- static int ax25_rcv(struct sk_buff *skb, struct net_device *dev,
- ax25_address *dev_addr, struct packet_type *ptype)
- {
- ax25_address src, dest, *next_digi = NULL;
- int type = 0, mine = 0, dama;
- struct sock *make, *sk;
- ax25_digi dp, reverse_dp;
- ax25_cb *ax25;
- ax25_dev *ax25_dev;
- /*
- * Process the AX.25/LAPB frame.
- */
- skb_reset_transport_header(skb);
- if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
- goto free;
- /*
- * Parse the address header.
- */
- if (ax25_addr_parse(skb->data, skb->len, &src, &dest, &dp, &type, &dama) == NULL)
- goto free;
- /*
- * Ours perhaps ?
- */
- if (dp.lastrepeat + 1 < dp.ndigi) /* Not yet digipeated completely */
- next_digi = &dp.calls[dp.lastrepeat + 1];
- /*
- * Pull of the AX.25 headers leaving the CTRL/PID bytes
- */
- skb_pull(skb, ax25_addr_size(&dp));
- /* For our port addresses ? */
- if (ax25cmp(&dest, dev_addr) == 0 && dp.lastrepeat + 1 == dp.ndigi)
- mine = 1;
- /* Also match on any registered callsign from L3/4 */
- if (!mine && ax25_listen_mine(&dest, dev) && dp.lastrepeat + 1 == dp.ndigi)
- mine = 1;
- /* UI frame - bypass LAPB processing */
- if ((*skb->data & ~0x10) == AX25_UI && dp.lastrepeat + 1 == dp.ndigi) {
- skb_set_transport_header(skb, 2); /* skip control and pid */
- ax25_send_to_raw(&dest, skb, skb->data[1]);
- if (!mine && ax25cmp(&dest, (ax25_address *)dev->broadcast) != 0)
- goto free;
- /* Now we are pointing at the pid byte */
- switch (skb->data[1]) {
- case AX25_P_IP:
- skb_pull(skb,2); /* drop PID/CTRL */
- skb_reset_transport_header(skb);
- skb_reset_network_header(skb);
- skb->dev = dev;
- skb->pkt_type = PACKET_HOST;
- skb->protocol = htons(ETH_P_IP);
- netif_rx(skb);
- break;
- case AX25_P_ARP:
- skb_pull(skb,2);
- skb_reset_transport_header(skb);
- skb_reset_network_header(skb);
- skb->dev = dev;
- skb->pkt_type = PACKET_HOST;
- skb->protocol = htons(ETH_P_ARP);
- netif_rx(skb);
- break;
- case AX25_P_TEXT:
- /* Now find a suitable dgram socket */
- sk = ax25_get_socket(&dest, &src, SOCK_DGRAM);
- if (sk != NULL) {
- bh_lock_sock(sk);
- if (atomic_read(&sk->sk_rmem_alloc) >=
- sk->sk_rcvbuf) {
- kfree_skb(skb);
- } else {
- /*
- * Remove the control and PID.
- */
- skb_pull(skb, 2);
- if (sock_queue_rcv_skb(sk, skb) != 0)
- kfree_skb(skb);
- }
- bh_unlock_sock(sk);
- sock_put(sk);
- } else {
- kfree_skb(skb);
- }
- break;
- default:
- kfree_skb(skb); /* Will scan SOCK_AX25 RAW sockets */
- break;
- }
- return 0;
- }
- /*
- * Is connected mode supported on this device ?
- * If not, should we DM the incoming frame (except DMs) or
- * silently ignore them. For now we stay quiet.
- */
- if (ax25_dev->values[AX25_VALUES_CONMODE] == 0)
- goto free;
- /* LAPB */
- /* AX.25 state 1-4 */
- ax25_digi_invert(&dp, &reverse_dp);
- if ((ax25 = ax25_find_cb(&dest, &src, &reverse_dp, dev)) != NULL) {
- /*
- * Process the frame. If it is queued up internally it
- * returns one otherwise we free it immediately. This
- * routine itself wakes the user context layers so we do
- * no further work
- */
- if (ax25_process_rx_frame(ax25, skb, type, dama) == 0)
- kfree_skb(skb);
- ax25_cb_put(ax25);
- return 0;
- }
- /* AX.25 state 0 (disconnected) */
- /* a) received not a SABM(E) */
- if ((*skb->data & ~AX25_PF) != AX25_SABM &&
- (*skb->data & ~AX25_PF) != AX25_SABME) {
- /*
- * Never reply to a DM. Also ignore any connects for
- * addresses that are not our interfaces and not a socket.
- */
- if ((*skb->data & ~AX25_PF) != AX25_DM && mine)
- ax25_return_dm(dev, &src, &dest, &dp);
- goto free;
- }
- /* b) received SABM(E) */
- if (dp.lastrepeat + 1 == dp.ndigi)
- sk = ax25_find_listener(&dest, 0, dev, SOCK_SEQPACKET);
- else
- sk = ax25_find_listener(next_digi, 1, dev, SOCK_SEQPACKET);
- if (sk != NULL) {
- bh_lock_sock(sk);
- if (sk_acceptq_is_full(sk) ||
- (make = ax25_make_new(sk, ax25_dev)) == NULL) {
- if (mine)
- ax25_return_dm(dev, &src, &dest, &dp);
- kfree_skb(skb);
- bh_unlock_sock(sk);
- sock_put(sk);
- return 0;
- }
- ax25 = ax25_sk(make);
- skb_set_owner_r(skb, make);
- skb_queue_head(&sk->sk_receive_queue, skb);
- make->sk_state = TCP_ESTABLISHED;
- sk->sk_ack_backlog++;
- bh_unlock_sock(sk);
- } else {
- if (!mine)
- goto free;
- if ((ax25 = ax25_create_cb()) == NULL) {
- ax25_return_dm(dev, &src, &dest, &dp);
- goto free;
- }
- ax25_fillin_cb(ax25, ax25_dev);
- }
- ax25->source_addr = dest;
- ax25->dest_addr = src;
- /*
- * Sort out any digipeated paths.
- */
- if (dp.ndigi && !ax25->digipeat &&
- (ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
- kfree_skb(skb);
- ax25_destroy_socket(ax25);
- if (sk)
- sock_put(sk);
- return 0;
- }
- if (dp.ndigi == 0) {
- kfree(ax25->digipeat);
- ax25->digipeat = NULL;
- } else {
- /* Reverse the source SABM's path */
- memcpy(ax25->digipeat, &reverse_dp, sizeof(ax25_digi));
- }
- if ((*skb->data & ~AX25_PF) == AX25_SABME) {
- ax25->modulus = AX25_EMODULUS;
- ax25->window = ax25_dev->values[AX25_VALUES_EWINDOW];
- } else {
- ax25->modulus = AX25_MODULUS;
- ax25->window = ax25_dev->values[AX25_VALUES_WINDOW];
- }
- ax25_send_control(ax25, AX25_UA, AX25_POLLON, AX25_RESPONSE);
- #ifdef CONFIG_AX25_DAMA_SLAVE
- if (dama && ax25->ax25_dev->values[AX25_VALUES_PROTOCOL] == AX25_PROTO_DAMA_SLAVE)
- ax25_dama_on(ax25);
- #endif
- ax25->state = AX25_STATE_3;
- ax25_cb_add(ax25);
- ax25_start_heartbeat(ax25);
- ax25_start_t3timer(ax25);
- ax25_start_idletimer(ax25);
- if (sk) {
- if (!sock_flag(sk, SOCK_DEAD))
- sk->sk_data_ready(sk, skb->len);
- sock_put(sk);
- } else {
- free:
- kfree_skb(skb);
- }
- return 0;
- }
- /*
- * Receive an AX.25 frame via a SLIP interface.
- */
- int ax25_kiss_rcv(struct sk_buff *skb, struct net_device *dev,
- struct packet_type *ptype, struct net_device *orig_dev)
- {
- skb_orphan(skb);
- if (!net_eq(dev_net(dev), &init_net)) {
- kfree_skb(skb);
- return 0;
- }
- if ((*skb->data & 0x0F) != 0) {
- kfree_skb(skb); /* Not a KISS data frame */
- return 0;
- }
- skb_pull(skb, AX25_KISS_HEADER_LEN); /* Remove the KISS byte */
- return ax25_rcv(skb, dev, (ax25_address *)dev->dev_addr, ptype);
- }
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