/* * 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) */ #include <linux/errno.h> #include <linux/types.h> #include <linux/socket.h> #include <linux/in.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/timer.h> #include <linux/string.h> #include <linux/sockios.h> #include <linux/spinlock.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 <asm/uaccess.h> #include <asm/system.h> #include <linux/fcntl.h> #include <linux/mm.h> #include <linux/interrupt.h> static DEFINE_SPINLOCK(ax25_frag_lock); ax25_cb *ax25_send_frame(struct sk_buff *skb, int paclen, ax25_address *src, ax25_address *dest, ax25_digi *digi, struct net_device *dev) { ax25_dev *ax25_dev; ax25_cb *ax25; /* * Take the default packet length for the device if zero is * specified. */ if (paclen == 0) { if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) return NULL; paclen = ax25_dev->values[AX25_VALUES_PACLEN]; } /* * Look for an existing connection. */ if ((ax25 = ax25_find_cb(src, dest, digi, dev)) != NULL) { ax25_output(ax25, paclen, skb); return ax25; /* It already existed */ } if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) return NULL; if ((ax25 = ax25_create_cb()) == NULL) return NULL; ax25_fillin_cb(ax25, ax25_dev); ax25->source_addr = *src; ax25->dest_addr = *dest; if (digi != NULL) { ax25->digipeat = kmemdup(digi, sizeof(*digi), GFP_ATOMIC); if (ax25->digipeat == NULL) { ax25_cb_put(ax25); return NULL; } } switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) { case AX25_PROTO_STD_SIMPLEX: case AX25_PROTO_STD_DUPLEX: ax25_std_establish_data_link(ax25); break; #ifdef CONFIG_AX25_DAMA_SLAVE case AX25_PROTO_DAMA_SLAVE: if (ax25_dev->dama.slave) ax25_ds_establish_data_link(ax25); else ax25_std_establish_data_link(ax25); break; #endif } /* * There is one ref for the state machine; a caller needs * one more to put it back, just like with the existing one. */ ax25_cb_hold(ax25); ax25_cb_add(ax25); ax25->state = AX25_STATE_1; ax25_start_heartbeat(ax25); ax25_output(ax25, paclen, skb); return ax25; /* We had to create it */ } EXPORT_SYMBOL(ax25_send_frame); /* * All outgoing AX.25 I frames pass via this routine. Therefore this is * where the fragmentation of frames takes place. If fragment is set to * zero then we are not allowed to do fragmentation, even if the frame * is too large. */ void ax25_output(ax25_cb *ax25, int paclen, struct sk_buff *skb) { struct sk_buff *skbn; unsigned char *p; int frontlen, len, fragno, ka9qfrag, first = 1; if (paclen < 16) { WARN_ON_ONCE(1); kfree_skb(skb); return; } if ((skb->len - 1) > paclen) { if (*skb->data == AX25_P_TEXT) { skb_pull(skb, 1); /* skip PID */ ka9qfrag = 0; } else { paclen -= 2; /* Allow for fragment control info */ ka9qfrag = 1; } fragno = skb->len / paclen; if (skb->len % paclen == 0) fragno--; frontlen = skb_headroom(skb); /* Address space + CTRL */ while (skb->len > 0) { spin_lock_bh(&ax25_frag_lock); if ((skbn = alloc_skb(paclen + 2 + frontlen, GFP_ATOMIC)) == NULL) { spin_unlock_bh(&ax25_frag_lock); printk(KERN_CRIT "AX.25: ax25_output - out of memory\n"); return; } if (skb->sk != NULL) skb_set_owner_w(skbn, skb->sk); spin_unlock_bh(&ax25_frag_lock); len = (paclen > skb->len) ? skb->len : paclen; if (ka9qfrag == 1) { skb_reserve(skbn, frontlen + 2); skb_set_network_header(skbn, skb_network_offset(skb)); skb_copy_from_linear_data(skb, skb_put(skbn, len), len); p = skb_push(skbn, 2); *p++ = AX25_P_SEGMENT; *p = fragno--; if (first) { *p |= AX25_SEG_FIRST; first = 0; } } else { skb_reserve(skbn, frontlen + 1); skb_set_network_header(skbn, skb_network_offset(skb)); skb_copy_from_linear_data(skb, skb_put(skbn, len), len); p = skb_push(skbn, 1); *p = AX25_P_TEXT; } skb_pull(skb, len); skb_queue_tail(&ax25->write_queue, skbn); /* Throw it on the queue */ } kfree_skb(skb); } else { skb_queue_tail(&ax25->write_queue, skb); /* Throw it on the queue */ } switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) { case AX25_PROTO_STD_SIMPLEX: case AX25_PROTO_STD_DUPLEX: ax25_kick(ax25); break; #ifdef CONFIG_AX25_DAMA_SLAVE /* * A DAMA slave is _required_ to work as normal AX.25L2V2 * if no DAMA master is available. */ case AX25_PROTO_DAMA_SLAVE: if (!ax25->ax25_dev->dama.slave) ax25_kick(ax25); break; #endif } } /* * This procedure is passed a buffer descriptor for an iframe. It builds * the rest of the control part of the frame and then writes it out. */ static void ax25_send_iframe(ax25_cb *ax25, struct sk_buff *skb, int poll_bit) { unsigned char *frame; if (skb == NULL) return; skb_reset_network_header(skb); if (ax25->modulus == AX25_MODULUS) { frame = skb_push(skb, 1); *frame = AX25_I; *frame |= (poll_bit) ? AX25_PF : 0; *frame |= (ax25->vr << 5); *frame |= (ax25->vs << 1); } else { frame = skb_push(skb, 2); frame[0] = AX25_I; frame[0] |= (ax25->vs << 1); frame[1] = (poll_bit) ? AX25_EPF : 0; frame[1] |= (ax25->vr << 1); } ax25_start_idletimer(ax25); ax25_transmit_buffer(ax25, skb, AX25_COMMAND); } void ax25_kick(ax25_cb *ax25) { struct sk_buff *skb, *skbn; int last = 1; unsigned short start, end, next; if (ax25->state != AX25_STATE_3 && ax25->state != AX25_STATE_4) return; if (ax25->condition & AX25_COND_PEER_RX_BUSY) return; if (skb_peek(&ax25->write_queue) == NULL) return; start = (skb_peek(&ax25->ack_queue) == NULL) ? ax25->va : ax25->vs; end = (ax25->va + ax25->window) % ax25->modulus; if (start == end) return; /* * Transmit data until either we're out of data to send or * the window is full. Send a poll on the final I frame if * the window is filled. */ /* * Dequeue the frame and copy it. * Check for race with ax25_clear_queues(). */ skb = skb_dequeue(&ax25->write_queue); if (!skb) return; ax25->vs = start; do { if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) { skb_queue_head(&ax25->write_queue, skb); break; } if (skb->sk != NULL) skb_set_owner_w(skbn, skb->sk); next = (ax25->vs + 1) % ax25->modulus; last = (next == end); /* * Transmit the frame copy. * bke 960114: do not set the Poll bit on the last frame * in DAMA mode. */ switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) { case AX25_PROTO_STD_SIMPLEX: case AX25_PROTO_STD_DUPLEX: ax25_send_iframe(ax25, skbn, (last) ? AX25_POLLON : AX25_POLLOFF); break; #ifdef CONFIG_AX25_DAMA_SLAVE case AX25_PROTO_DAMA_SLAVE: ax25_send_iframe(ax25, skbn, AX25_POLLOFF); break; #endif } ax25->vs = next; /* * Requeue the original data frame. */ skb_queue_tail(&ax25->ack_queue, skb); } while (!last && (skb = skb_dequeue(&ax25->write_queue)) != NULL); ax25->condition &= ~AX25_COND_ACK_PENDING; if (!ax25_t1timer_running(ax25)) { ax25_stop_t3timer(ax25); ax25_calculate_t1(ax25); ax25_start_t1timer(ax25); } } void ax25_transmit_buffer(ax25_cb *ax25, struct sk_buff *skb, int type) { struct sk_buff *skbn; unsigned char *ptr; int headroom; if (ax25->ax25_dev == NULL) { ax25_disconnect(ax25, ENETUNREACH); return; } headroom = ax25_addr_size(ax25->digipeat); if (skb_headroom(skb) < headroom) { if ((skbn = skb_realloc_headroom(skb, headroom)) == NULL) { printk(KERN_CRIT "AX.25: ax25_transmit_buffer - out of memory\n"); kfree_skb(skb); return; } if (skb->sk != NULL) skb_set_owner_w(skbn, skb->sk); kfree_skb(skb); skb = skbn; } ptr = skb_push(skb, headroom); ax25_addr_build(ptr, &ax25->source_addr, &ax25->dest_addr, ax25->digipeat, type, ax25->modulus); ax25_queue_xmit(skb, ax25->ax25_dev->dev); } /* * A small shim to dev_queue_xmit to add the KISS control byte, and do * any packet forwarding in operation. */ void ax25_queue_xmit(struct sk_buff *skb, struct net_device *dev) { unsigned char *ptr; skb->protocol = ax25_type_trans(skb, ax25_fwd_dev(dev)); ptr = skb_push(skb, 1); *ptr = 0x00; /* KISS */ dev_queue_xmit(skb); } int ax25_check_iframes_acked(ax25_cb *ax25, unsigned short nr) { if (ax25->vs == nr) { ax25_frames_acked(ax25, nr); ax25_calculate_rtt(ax25); ax25_stop_t1timer(ax25); ax25_start_t3timer(ax25); return 1; } else { if (ax25->va != nr) { ax25_frames_acked(ax25, nr); ax25_calculate_t1(ax25); ax25_start_t1timer(ax25); return 1; } } return 0; }