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[/] [or1k/] [tags/] [before_ORP/] [uclinux/] [uClinux-2.0.x/] [net/] [ax25/] [ax25_in.c] - Rev 1765
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/* * AX.25 release 035 * * This code REQUIRES 1.2.1 or higher/ NET3.029 * * This module: * This module 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. * * Most of this code is based on the SDL diagrams published in the 7th * ARRL Computer Networking Conference papers. The diagrams have mistakes * in them, but are mostly correct. Before you modify the code could you * read the SDL diagrams as the code is not obvious and probably very * easy to break; * * History * AX.25 028a Jonathan(G4KLX) New state machine based on SDL diagrams. * AX.25 028b Jonathan(G4KLX) Extracted AX25 control block from * the sock structure. * AX.25 029 Alan(GW4PTS) Switched to KA9Q constant names. * Jonathan(G4KLX) Added IP mode registration. * AX.25 030 Jonathan(G4KLX) Added AX.25 fragment reception. * Upgraded state machine for SABME. * Added arbitrary protocol id support. * AX.25 031 Joerg(DL1BKE) Added DAMA support * HaJo(DD8NE) Added Idle Disc Timer T5 * Joerg(DL1BKE) Renamed it to "IDLE" with a slightly * different behaviour. Fixed defrag * routine (I hope) * AX.25 032 Darryl(G7LED) AX.25 segmentation fixed. * AX.25 033 Jonathan(G4KLX) Remove auto-router. * Modularisation changes. * Joerg(DL1BKE) Fixed 2.0.x specific IP over AX.25 problem. */ #include <linux/config.h> #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) #include <linux/errno.h> #include <linux/types.h> #include <linux/socket.h> #include <linux/in.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/timer.h> #include <linux/string.h> #include <linux/sockios.h> #include <linux/net.h> #include <net/ax25.h> #include <linux/inet.h> #include <linux/netdevice.h> #include <linux/skbuff.h> #include <net/sock.h> #include <net/ip.h> /* For ip_rcv */ #include <asm/segment.h> #include <asm/system.h> #include <linux/fcntl.h> #include <linux/mm.h> #include <linux/interrupt.h> static int ax25_rx_iframe(ax25_cb *, struct sk_buff *); /* * 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) { if ((skbn = alloc_skb(AX25_MAX_HEADER_LEN + ax25->fraglen, GFP_ATOMIC)) == NULL) { while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) kfree_skb(skbo, FREE_READ); return 1; } skb_reserve(skbn, AX25_MAX_HEADER_LEN); skbn->free = 1; skbn->dev = ax25->device; skbn->h.raw = skbn->data; /* Copy data from the fragments */ while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) { memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len); kfree_skb(skbo, FREE_READ); } ax25->fraglen = 0; if (ax25_rx_iframe(ax25, skbn) == 0) kfree_skb(skbn, FREE_READ); } return 1; } } } else { /* First fragment received */ if (*skb->data & AX25_SEG_FIRST) { while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) kfree_skb(skbo, FREE_READ); 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. */ static int ax25_rx_iframe(ax25_cb *ax25, struct sk_buff *skb) { int (*func)(struct sk_buff *, ax25_cb *); struct sk_buff *skbn; volatile int queued = 0; unsigned char pid; if (skb == NULL) return 0; ax25->idletimer = ax25->idle; pid = *skb->data; #ifdef CONFIG_INET if (pid == AX25_P_IP) { if ((skbn = skb_copy(skb, GFP_ATOMIC)) != NULL) { kfree_skb(skb, FREE_READ); skb = skbn; } skb_pull(skb, 1); /* Remove PID */ skb->h.raw = skb->data; ip_rcv(skb, ax25->device, NULL); /* Wrong ptype */ return 1; } #endif 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_dev_get_value(ax25->device, AX25_VALUES_CONMODE) == 2) { if ((!ax25->pidincl && ax25->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; } /* * State machine for state 1, Awaiting Connection State. * The handling of the timer(s) is in file ax25_timer.c. * Handling of state 0 and connection release is in ax25.c. */ static int ax25_state1_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type, int dama) { switch (frametype) { case AX25_SABM: ax25->modulus = AX25_MODULUS; ax25->window = ax25_dev_get_value(ax25->device, AX25_VALUES_WINDOW); ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); break; case AX25_SABME: ax25->modulus = AX25_EMODULUS; ax25->window = ax25_dev_get_value(ax25->device, AX25_VALUES_EWINDOW); ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); break; case AX25_DISC: ax25_send_control(ax25, AX25_DM, pf, AX25_RESPONSE); break; case AX25_UA: if (pf || dama) { if (dama) ax25_dama_on(ax25); /* bke */ ax25_calculate_rtt(ax25); ax25->t1timer = 0; ax25->t3timer = ax25->t3; ax25->idletimer = ax25->idle; ax25->vs = 0; ax25->va = 0; ax25->vr = 0; ax25->state = AX25_STATE_3; ax25->n2count = 0; ax25->dama_slave = dama; /* bke */ if (ax25->sk != NULL) { ax25->sk->state = TCP_ESTABLISHED; /* For WAIT_SABM connections we will produce an accept ready socket here */ if (!ax25->sk->dead) ax25->sk->state_change(ax25->sk); } } break; case AX25_DM: if (pf) { if (ax25->modulus == AX25_MODULUS) { ax25_disconnect(ax25, ECONNREFUSED); } else { ax25->modulus = AX25_MODULUS; ax25->window = ax25_dev_get_value(ax25->device, AX25_VALUES_WINDOW); } } break; default: if (dama && pf) ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND); break; } return 0; } /* * State machine for state 2, Awaiting Release State. * The handling of the timer(s) is in file ax25_timer.c * Handling of state 0 and connection release is in ax25.c. */ static int ax25_state2_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type) { switch (frametype) { case AX25_SABM: case AX25_SABME: ax25_send_control(ax25, AX25_DM, pf, AX25_RESPONSE); if (ax25->dama_slave) ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); break; case AX25_DISC: ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); if (ax25->dama_slave) ax25_disconnect(ax25, 0); break; case AX25_DM: case AX25_UA: if (pf) ax25_disconnect(ax25, 0); break; case AX25_I: case AX25_REJ: case AX25_RNR: case AX25_RR: if (pf) { if (ax25->dama_slave) ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); else ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE); } break; default: break; } return 0; } /* * State machine for state 3, Connected State. * The handling of the timer(s) is in file ax25_timer.c * Handling of state 0 and connection release is in ax25.c. */ static int ax25_state3_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int ns, int nr, int pf, int type, int dama) { int queued = 0; switch (frametype) { case AX25_SABM: case AX25_SABME: if (dama) ax25_dama_on(ax25); if (frametype == AX25_SABM) { ax25->modulus = AX25_MODULUS; ax25->window = ax25_dev_get_value(ax25->device, AX25_VALUES_WINDOW); } else { ax25->modulus = AX25_EMODULUS; ax25->window = ax25_dev_get_value(ax25->device, AX25_VALUES_EWINDOW); } ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); ax25->condition = 0x00; ax25->t1timer = 0; ax25->t3timer = ax25->t3; ax25->idletimer = ax25->idle; ax25->vs = 0; ax25->va = 0; ax25->vr = 0; ax25->dama_slave = dama; ax25_requeue_frames(ax25); break; case AX25_DISC: ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); ax25_disconnect(ax25, 0); break; case AX25_DM: ax25_disconnect(ax25, ECONNRESET); break; case AX25_RR: case AX25_RNR: if (frametype == AX25_RR) ax25->condition &= ~AX25_COND_PEER_RX_BUSY; else ax25->condition |= AX25_COND_PEER_RX_BUSY; if (!ax25->dama_slave && type == AX25_COMMAND && pf) ax25_enquiry_response(ax25); if (ax25_validate_nr(ax25, nr)) { ax25_check_iframes_acked(ax25, nr); if (ax25->dama_slave && type == AX25_COMMAND && pf) dama_enquiry_response(ax25); } else { ax25_nr_error_recovery(ax25); ax25->state = AX25_STATE_1; } break; case AX25_REJ: ax25->condition &= ~AX25_COND_PEER_RX_BUSY; if (!ax25->dama_slave && type == AX25_COMMAND && pf) ax25_enquiry_response(ax25); if (ax25_validate_nr(ax25, nr)) { ax25_frames_acked(ax25, nr); ax25_calculate_rtt(ax25); ax25->t1timer = 0; ax25->t3timer = ax25->t3; ax25_requeue_frames(ax25); if (ax25->dama_slave && type == AX25_COMMAND && pf) dama_enquiry_response(ax25); } else { ax25_nr_error_recovery(ax25); ax25->state = AX25_STATE_1; } break; case AX25_I: if (!ax25_validate_nr(ax25, nr)) { ax25_nr_error_recovery(ax25); ax25->state = AX25_STATE_1; break; } if (ax25->condition & AX25_COND_PEER_RX_BUSY) { ax25_frames_acked(ax25, nr); } else { ax25_check_iframes_acked(ax25, nr); } if (ax25->condition & AX25_COND_OWN_RX_BUSY) { if (pf) { if (ax25->dama_slave) dama_enquiry_response(ax25); else ax25_enquiry_response(ax25); } break; } if (ns == ax25->vr) { ax25->vr = (ax25->vr + 1) % ax25->modulus; queued = ax25_rx_iframe(ax25, skb); if (ax25->condition & AX25_COND_OWN_RX_BUSY) ax25->vr = ns; /* ax25->vr - 1 */ ax25->condition &= ~AX25_COND_REJECT; if (pf) { if (ax25->dama_slave) dama_enquiry_response(ax25); else ax25_enquiry_response(ax25); } else { if (!(ax25->condition & AX25_COND_ACK_PENDING)) { ax25->t2timer = ax25->t2; ax25->condition |= AX25_COND_ACK_PENDING; } } } else { if (ax25->condition & AX25_COND_REJECT) { if (pf) { if (ax25->dama_slave) dama_enquiry_response(ax25); else ax25_enquiry_response(ax25); } } else { ax25->condition |= AX25_COND_REJECT; if (ax25->dama_slave) dama_enquiry_response(ax25); else ax25_send_control(ax25, AX25_REJ, pf, AX25_RESPONSE); ax25->condition &= ~AX25_COND_ACK_PENDING; } } break; case AX25_FRMR: case AX25_ILLEGAL: ax25_establish_data_link(ax25); ax25->state = AX25_STATE_1; break; default: break; } return queued; } /* * State machine for state 4, Timer Recovery State. * The handling of the timer(s) is in file ax25_timer.c * Handling of state 0 and connection release is in ax25.c. */ static int ax25_state4_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int ns, int nr, int pf, int type, int dama) { int queued = 0; switch (frametype) { case AX25_SABM: case AX25_SABME: if (dama) ax25_dama_on(ax25); if (frametype == AX25_SABM) { ax25->modulus = AX25_MODULUS; ax25->window = ax25_dev_get_value(ax25->device, AX25_VALUES_WINDOW); } else { ax25->modulus = AX25_EMODULUS; ax25->window = ax25_dev_get_value(ax25->device, AX25_VALUES_EWINDOW); } ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); ax25->condition = 0x00; ax25->t1timer = 0; ax25->t3timer = ax25->t3; ax25->idletimer = ax25->idle; ax25->vs = 0; ax25->va = 0; ax25->vr = 0; ax25->state = AX25_STATE_3; ax25->n2count = 0; ax25->dama_slave = dama; ax25_requeue_frames(ax25); break; case AX25_DISC: ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); ax25_disconnect(ax25, 0); break; case AX25_DM: ax25_disconnect(ax25, ECONNRESET); break; case AX25_RR: case AX25_RNR: if (frametype == AX25_RR) ax25->condition &= ~AX25_COND_PEER_RX_BUSY; else ax25->condition |= AX25_COND_PEER_RX_BUSY; if (type == AX25_RESPONSE && pf) { ax25->t1timer = 0; if (ax25_validate_nr(ax25, nr)) { ax25_frames_acked(ax25, nr); if (ax25->vs == ax25->va) { ax25->t3timer = ax25->t3; ax25->n2count = 0; ax25->state = AX25_STATE_3; } else { ax25_requeue_frames(ax25); } } else { ax25_nr_error_recovery(ax25); ax25->state = AX25_STATE_1; } break; } if (!ax25->dama_slave && type == AX25_COMMAND && pf) ax25_enquiry_response(ax25); if (ax25_validate_nr(ax25, nr)) { ax25_frames_acked(ax25, nr); if (ax25->dama_slave && type == AX25_COMMAND && pf) dama_enquiry_response(ax25); } else { ax25_nr_error_recovery(ax25); ax25->state = AX25_STATE_1; } break; case AX25_REJ: ax25->condition &= ~AX25_COND_PEER_RX_BUSY; if (pf && (type == AX25_RESPONSE || (ax25->dama_slave && type == AX25_COMMAND))) { ax25->t1timer = 0; if (ax25_validate_nr(ax25, nr)) { ax25_frames_acked(ax25, nr); if (ax25->vs == ax25->va) { ax25->t3timer = ax25->t3; ax25->n2count = 0; ax25->state = AX25_STATE_3; } else { ax25_requeue_frames(ax25); } if (ax25->dama_slave && type == AX25_COMMAND && pf) dama_enquiry_response(ax25); } else { ax25_nr_error_recovery(ax25); ax25->state = AX25_STATE_1; } break; } if (!ax25->dama_slave && type == AX25_COMMAND && pf) ax25_enquiry_response(ax25); if (ax25_validate_nr(ax25, nr)) { ax25_frames_acked(ax25, nr); ax25_requeue_frames(ax25); if (ax25->dama_slave && type == AX25_COMMAND && pf) dama_enquiry_response(ax25); } else { ax25_nr_error_recovery(ax25); ax25->state = AX25_STATE_1; } break; case AX25_I: if (!ax25_validate_nr(ax25, nr)) { ax25_nr_error_recovery(ax25); ax25->state = AX25_STATE_1; break; } ax25_frames_acked(ax25, nr); if (ax25->condition & AX25_COND_OWN_RX_BUSY) { if (pf) { if (ax25->dama_slave) ax25_enquiry_response(ax25); else dama_enquiry_response(ax25); } break; } if (ns == ax25->vr) { ax25->vr = (ax25->vr + 1) % ax25->modulus; queued = ax25_rx_iframe(ax25, skb); if (ax25->condition & AX25_COND_OWN_RX_BUSY) ax25->vr = ns; /* ax25->vr - 1 */ ax25->condition &= ~AX25_COND_REJECT; if (pf) { if (ax25->dama_slave) dama_enquiry_response(ax25); else ax25_enquiry_response(ax25); } else { if (!(ax25->condition & AX25_COND_ACK_PENDING)) { ax25->t2timer = ax25->t2; ax25->condition |= AX25_COND_ACK_PENDING; } } } else { if (ax25->condition & AX25_COND_REJECT) { if (pf) { if (ax25->dama_slave) dama_enquiry_response(ax25); else ax25_enquiry_response(ax25); } } else { ax25->condition |= AX25_COND_REJECT; if (ax25->dama_slave) dama_enquiry_response(ax25); else ax25_send_control(ax25, AX25_REJ, pf, AX25_RESPONSE); ax25->condition &= ~AX25_COND_ACK_PENDING; } } break; case AX25_FRMR: case AX25_ILLEGAL: ax25_establish_data_link(ax25); ax25->state = AX25_STATE_1; break; default: break; } return queued; } /* * Higher level upcall for a LAPB frame */ int ax25_process_rx_frame(ax25_cb *ax25, struct sk_buff *skb, int type, int dama) { int queued = 0, frametype, ns, nr, pf; if (ax25->state == AX25_STATE_0) return 0; del_timer(&ax25->timer); frametype = ax25_decode(ax25, skb, &ns, &nr, &pf); switch (ax25->state) { case AX25_STATE_1: queued = ax25_state1_machine(ax25, skb, frametype, pf, type, dama); break; case AX25_STATE_2: queued = ax25_state2_machine(ax25, skb, frametype, pf, type); break; case AX25_STATE_3: queued = ax25_state3_machine(ax25, skb, frametype, ns, nr, pf, type, dama); break; case AX25_STATE_4: queued = ax25_state4_machine(ax25, skb, frametype, ns, nr, pf, type, dama); break; } ax25_set_timer(ax25); return queued; } #endif