nr_in.c
上传用户:jlfgdled
上传日期:2013-04-10
资源大小:33168k
文件大小:8k
- /*
- * NET/ROM release 007
- *
- * This code REQUIRES 2.1.15 or higher/ NET3.038
- *
- * 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
- * NET/ROM 001 Jonathan(G4KLX) Cloned from ax25_in.c
- * NET/ROM 003 Jonathan(G4KLX) Added NET/ROM fragment reception.
- * Darryl(G7LED) Added missing INFO with NAK case, optimized
- * INFOACK handling, removed reconnect on error.
- * NET/ROM 006 Jonathan(G4KLX) Hdrincl removal changes.
- * NET/ROM 007 Jonathan(G4KLX) New timer architecture.
- */
- #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/uaccess.h>
- #include <asm/system.h>
- #include <linux/fcntl.h>
- #include <linux/mm.h>
- #include <linux/interrupt.h>
- #include <net/netrom.h>
- static int nr_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
- {
- struct sk_buff *skbo, *skbn = skb;
- skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
- nr_start_idletimer(sk);
- if (more) {
- sk->protinfo.nr->fraglen += skb->len;
- skb_queue_tail(&sk->protinfo.nr->frag_queue, skb);
- return 0;
- }
- if (!more && sk->protinfo.nr->fraglen > 0) { /* End of fragment */
- sk->protinfo.nr->fraglen += skb->len;
- skb_queue_tail(&sk->protinfo.nr->frag_queue, skb);
- if ((skbn = alloc_skb(sk->protinfo.nr->fraglen, GFP_ATOMIC)) == NULL)
- return 1;
- skbn->h.raw = skbn->data;
- while ((skbo = skb_dequeue(&sk->protinfo.nr->frag_queue)) != NULL) {
- memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
- kfree_skb(skbo);
- }
- sk->protinfo.nr->fraglen = 0;
- }
- return sock_queue_rcv_skb(sk, skbn);
- }
- /*
- * State machine for state 1, Awaiting Connection State.
- * The handling of the timer(s) is in file nr_timer.c.
- * Handling of state 0 and connection release is in netrom.c.
- */
- static int nr_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
- {
- switch (frametype) {
- case NR_CONNACK:
- nr_stop_t1timer(sk);
- nr_start_idletimer(sk);
- sk->protinfo.nr->your_index = skb->data[17];
- sk->protinfo.nr->your_id = skb->data[18];
- sk->protinfo.nr->vs = 0;
- sk->protinfo.nr->va = 0;
- sk->protinfo.nr->vr = 0;
- sk->protinfo.nr->vl = 0;
- sk->protinfo.nr->state = NR_STATE_3;
- sk->protinfo.nr->n2count = 0;
- sk->protinfo.nr->window = skb->data[20];
- sk->state = TCP_ESTABLISHED;
- if (!sk->dead)
- sk->state_change(sk);
- break;
- case NR_CONNACK | NR_CHOKE_FLAG:
- nr_disconnect(sk, ECONNREFUSED);
- break;
- default:
- break;
- }
- return 0;
- }
- /*
- * State machine for state 2, Awaiting Release State.
- * The handling of the timer(s) is in file nr_timer.c
- * Handling of state 0 and connection release is in netrom.c.
- */
- static int nr_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
- {
- switch (frametype) {
- case NR_CONNACK | NR_CHOKE_FLAG:
- nr_disconnect(sk, ECONNRESET);
- break;
- case NR_DISCREQ:
- nr_write_internal(sk, NR_DISCACK);
- case NR_DISCACK:
- nr_disconnect(sk, 0);
- break;
- default:
- break;
- }
- return 0;
- }
- /*
- * State machine for state 3, Connected State.
- * The handling of the timer(s) is in file nr_timer.c
- * Handling of state 0 and connection release is in netrom.c.
- */
- static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype)
- {
- struct sk_buff_head temp_queue;
- struct sk_buff *skbn;
- unsigned short save_vr;
- unsigned short nr, ns;
- int queued = 0;
- nr = skb->data[18];
- ns = skb->data[17];
- switch (frametype) {
- case NR_CONNREQ:
- nr_write_internal(sk, NR_CONNACK);
- break;
- case NR_DISCREQ:
- nr_write_internal(sk, NR_DISCACK);
- nr_disconnect(sk, 0);
- break;
- case NR_CONNACK | NR_CHOKE_FLAG:
- case NR_DISCACK:
- nr_disconnect(sk, ECONNRESET);
- break;
- case NR_INFOACK:
- case NR_INFOACK | NR_CHOKE_FLAG:
- case NR_INFOACK | NR_NAK_FLAG:
- case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG:
- if (frametype & NR_CHOKE_FLAG) {
- sk->protinfo.nr->condition |= NR_COND_PEER_RX_BUSY;
- nr_start_t4timer(sk);
- } else {
- sk->protinfo.nr->condition &= ~NR_COND_PEER_RX_BUSY;
- nr_stop_t4timer(sk);
- }
- if (!nr_validate_nr(sk, nr)) {
- break;
- }
- if (frametype & NR_NAK_FLAG) {
- nr_frames_acked(sk, nr);
- nr_send_nak_frame(sk);
- } else {
- if (sk->protinfo.nr->condition & NR_COND_PEER_RX_BUSY) {
- nr_frames_acked(sk, nr);
- } else {
- nr_check_iframes_acked(sk, nr);
- }
- }
- break;
- case NR_INFO:
- case NR_INFO | NR_NAK_FLAG:
- case NR_INFO | NR_CHOKE_FLAG:
- case NR_INFO | NR_MORE_FLAG:
- case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG:
- case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG:
- case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG:
- case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG:
- if (frametype & NR_CHOKE_FLAG) {
- sk->protinfo.nr->condition |= NR_COND_PEER_RX_BUSY;
- nr_start_t4timer(sk);
- } else {
- sk->protinfo.nr->condition &= ~NR_COND_PEER_RX_BUSY;
- nr_stop_t4timer(sk);
- }
- if (nr_validate_nr(sk, nr)) {
- if (frametype & NR_NAK_FLAG) {
- nr_frames_acked(sk, nr);
- nr_send_nak_frame(sk);
- } else {
- if (sk->protinfo.nr->condition & NR_COND_PEER_RX_BUSY) {
- nr_frames_acked(sk, nr);
- } else {
- nr_check_iframes_acked(sk, nr);
- }
- }
- }
- queued = 1;
- skb_queue_head(&sk->protinfo.nr->reseq_queue, skb);
- if (sk->protinfo.nr->condition & NR_COND_OWN_RX_BUSY)
- break;
- skb_queue_head_init(&temp_queue);
- do {
- save_vr = sk->protinfo.nr->vr;
- while ((skbn = skb_dequeue(&sk->protinfo.nr->reseq_queue)) != NULL) {
- ns = skbn->data[17];
- if (ns == sk->protinfo.nr->vr) {
- if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) {
- sk->protinfo.nr->vr = (sk->protinfo.nr->vr + 1) % NR_MODULUS;
- } else {
- sk->protinfo.nr->condition |= NR_COND_OWN_RX_BUSY;
- skb_queue_tail(&temp_queue, skbn);
- }
- } else if (nr_in_rx_window(sk, ns)) {
- skb_queue_tail(&temp_queue, skbn);
- } else {
- kfree_skb(skbn);
- }
- }
- while ((skbn = skb_dequeue(&temp_queue)) != NULL) {
- skb_queue_tail(&sk->protinfo.nr->reseq_queue, skbn);
- }
- } while (save_vr != sk->protinfo.nr->vr);
- /*
- * Window is full, ack it immediately.
- */
- if (((sk->protinfo.nr->vl + sk->protinfo.nr->window) % NR_MODULUS) == sk->protinfo.nr->vr) {
- nr_enquiry_response(sk);
- } else {
- if (!(sk->protinfo.nr->condition & NR_COND_ACK_PENDING)) {
- sk->protinfo.nr->condition |= NR_COND_ACK_PENDING;
- nr_start_t2timer(sk);
- }
- }
- break;
- default:
- break;
- }
- return queued;
- }
- /* Higher level upcall for a LAPB frame */
- int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb)
- {
- int queued = 0, frametype;
- if (sk->protinfo.nr->state == NR_STATE_0)
- return 0;
- frametype = skb->data[19];
- switch (sk->protinfo.nr->state) {
- case NR_STATE_1:
- queued = nr_state1_machine(sk, skb, frametype);
- break;
- case NR_STATE_2:
- queued = nr_state2_machine(sk, skb, frametype);
- break;
- case NR_STATE_3:
- queued = nr_state3_machine(sk, skb, frametype);
- break;
- }
- nr_kick(sk);
- return queued;
- }