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-rw-r--r--net/ax25/ax25_in.c454
1 files changed, 454 insertions, 0 deletions
diff --git a/net/ax25/ax25_in.c b/net/ax25/ax25_in.c
new file mode 100644
index 000000000..860752639
--- /dev/null
+++ b/net/ax25/ax25_in.c
@@ -0,0 +1,454 @@
+/*
+ * 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 <net/sock.h>
+#include <net/tcp_states.h>
+#include <linux/uaccess.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 = sk_to_ax25(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);
+ 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);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-27 18:29:41 +0000