rose_subr.c

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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) Jonathan Naylor G4KLX ([email protected])
 */
#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/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <net/rose.h>

static int rose_create_facilities(unsigned char *buffer, struct rose_sock *rose);

/*
 *  This routine purges all of the queues of frames.
 */
void rose_clear_queues(struct sock *sk)
{
    skb_queue_purge(&sk->sk_write_queue);
    skb_queue_purge(&rose_sk(sk)->ack_queue);
}

/*
 * This routine purges the input queue of those frames that have been
 * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
 * SDL diagram.
 */
void rose_frames_acked(struct sock *sk, unsigned short nr)
{
    struct sk_buff *skb;
    struct rose_sock *rose = rose_sk(sk);

    /*
     * Remove all the ack-ed frames from the ack queue.
     */
    if (rose->va != nr) {
        while (skb_peek(&rose->ack_queue) != NULL && rose->va != nr) {
            skb = skb_dequeue(&rose->ack_queue);
            kfree_skb(skb);
            rose->va = (rose->va + 1) % ROSE_MODULUS;
        }
    }
}

void rose_requeue_frames(struct sock *sk)
{
    struct sk_buff *skb, *skb_prev = NULL;

    /*
     * Requeue all the un-ack-ed frames on the output queue to be picked
     * up by rose_kick. This arrangement handles the possibility of an
     * empty output queue.
     */
    while ((skb = skb_dequeue(&rose_sk(sk)->ack_queue)) != NULL) {
        if (skb_prev == NULL)
            skb_queue_head(&sk->sk_write_queue, skb);
        else
            skb_append(skb_prev, skb, &sk->sk_write_queue);
        skb_prev = skb;
    }
}

/*
 *  Validate that the value of nr is between va and vs. Return true or
 *  false for testing.
 */
int rose_validate_nr(struct sock *sk, unsigned short nr)
{
    struct rose_sock *rose = rose_sk(sk);
    unsigned short vc = rose->va;

    while (vc != rose->vs) {
        if (nr == vc) return 1;
        vc = (vc + 1) % ROSE_MODULUS;
    }

    return nr == rose->vs;
}

/*
 *  This routine is called when the packet layer internally generates a
 *  control frame.
 */
void rose_write_internal(struct sock *sk, int frametype)
{
    struct rose_sock *rose = rose_sk(sk);
    struct sk_buff *skb;
    unsigned char  *dptr;
    unsigned char  lci1, lci2;
    char buffer[100];
    int len, faclen = 0;

    len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 1;

    switch (frametype) {
    case ROSE_CALL_REQUEST:
        len   += 1 + ROSE_ADDR_LEN + ROSE_ADDR_LEN;
        faclen = rose_create_facilities(buffer, rose);
        len   += faclen;
        break;
    case ROSE_CALL_ACCEPTED:
    case ROSE_CLEAR_REQUEST:
    case ROSE_RESET_REQUEST:
        len   += 2;
        break;
    }

    if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
        return;

    /*
     *  Space for AX.25 header and PID.
     */
    skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + 1);

    dptr = skb_put(skb, skb_tailroom(skb));

    lci1 = (rose->lci >> 8) & 0x0F;
    lci2 = (rose->lci >> 0) & 0xFF;

    switch (frametype) {
    case ROSE_CALL_REQUEST:
        *dptr++ = ROSE_GFI | lci1;
        *dptr++ = lci2;
        *dptr++ = frametype;
        *dptr++ = ROSE_CALL_REQ_ADDR_LEN_VAL;
        memcpy(dptr, &rose->dest_addr,  ROSE_ADDR_LEN);
        dptr   += ROSE_ADDR_LEN;
        memcpy(dptr, &rose->source_addr, ROSE_ADDR_LEN);
        dptr   += ROSE_ADDR_LEN;
        memcpy(dptr, buffer, faclen);
        dptr   += faclen;
        break;

    case ROSE_CALL_ACCEPTED:
        *dptr++ = ROSE_GFI | lci1;
        *dptr++ = lci2;
        *dptr++ = frametype;
        *dptr++ = 0x00;     /* Address length */
        *dptr++ = 0;        /* Facilities length */
        break;

    case ROSE_CLEAR_REQUEST:
        *dptr++ = ROSE_GFI | lci1;
        *dptr++ = lci2;
        *dptr++ = frametype;
        *dptr++ = rose->cause;
        *dptr++ = rose->diagnostic;
        break;

    case ROSE_RESET_REQUEST:
        *dptr++ = ROSE_GFI | lci1;
        *dptr++ = lci2;
        *dptr++ = frametype;
        *dptr++ = ROSE_DTE_ORIGINATED;
        *dptr++ = 0;
        break;

    case ROSE_RR:
    case ROSE_RNR:
        *dptr++ = ROSE_GFI | lci1;
        *dptr++ = lci2;
        *dptr   = frametype;
        *dptr++ |= (rose->vr << 5) & 0xE0;
        break;

    case ROSE_CLEAR_CONFIRMATION:
    case ROSE_RESET_CONFIRMATION:
        *dptr++ = ROSE_GFI | lci1;
        *dptr++ = lci2;
        *dptr++  = frametype;
        break;

    default:
        printk(KERN_ERR "ROSE: rose_write_internal - invalid frametype %02X\n", frametype);
        kfree_skb(skb);
        return;
    }

    rose_transmit_link(skb, rose->neighbour);
}

int rose_decode(struct sk_buff *skb, int *ns, int *nr, int *q, int *d, int *m)
{
    unsigned char *frame;

    frame = skb->data;

    *ns = *nr = *q = *d = *m = 0;

    switch (frame[2]) {
    case ROSE_CALL_REQUEST:
    case ROSE_CALL_ACCEPTED:
    case ROSE_CLEAR_REQUEST:
    case ROSE_CLEAR_CONFIRMATION:
    case ROSE_RESET_REQUEST:
    case ROSE_RESET_CONFIRMATION:
        return frame[2];
    default:
        break;
    }

    if ((frame[2] & 0x1F) == ROSE_RR  ||
        (frame[2] & 0x1F) == ROSE_RNR) {
        *nr = (frame[2] >> 5) & 0x07;
        return frame[2] & 0x1F;
    }

    if ((frame[2] & 0x01) == ROSE_DATA) {
        *q  = (frame[0] & ROSE_Q_BIT) == ROSE_Q_BIT;
        *d  = (frame[0] & ROSE_D_BIT) == ROSE_D_BIT;
        *m  = (frame[2] & ROSE_M_BIT) == ROSE_M_BIT;
        *nr = (frame[2] >> 5) & 0x07;
        *ns = (frame[2] >> 1) & 0x07;
        return ROSE_DATA;
    }

    return ROSE_ILLEGAL;
}

static int rose_parse_national(unsigned char *p, struct rose_facilities_struct *facilities, int len)
{
    unsigned char *pt;
    unsigned char l, lg, n = 0;
    int fac_national_digis_received = 0;

    do {
        switch (*p & 0xC0) {
        case 0x00:
            if (len < 2)
                return -1;
            p   += 2;
            n   += 2;
            len -= 2;
            break;

        case 0x40:
            if (len < 3)
                return -1;
            if (*p == FAC_NATIONAL_RAND)
                facilities->rand = ((p[1] << 8) & 0xFF00) + ((p[2] << 0) & 0x00FF);
            p   += 3;
            n   += 3;
            len -= 3;
            break;

        case 0x80:
            if (len < 4)
                return -1;
            p   += 4;
            n   += 4;
            len -= 4;
            break;

        case 0xC0:
            if (len < 2)
                return -1;
            l = p[1];
            if (len < 2 + l)
                return -1;
            if (*p == FAC_NATIONAL_DEST_DIGI) {
                if (!fac_national_digis_received) {
                    if (l < AX25_ADDR_LEN)
                        return -1;
                    memcpy(&facilities->source_digis[0], p + 2, AX25_ADDR_LEN);
                    facilities->source_ndigis = 1;
                }
            }
            else if (*p == FAC_NATIONAL_SRC_DIGI) {
                if (!fac_national_digis_received) {
                    if (l < AX25_ADDR_LEN)
                        return -1;
                    memcpy(&facilities->dest_digis[0], p + 2, AX25_ADDR_LEN);
                    facilities->dest_ndigis = 1;
                }
            }
            else if (*p == FAC_NATIONAL_FAIL_CALL) {
                if (l < AX25_ADDR_LEN)
                    return -1;
                memcpy(&facilities->fail_call, p + 2, AX25_ADDR_LEN);
            }
            else if (*p == FAC_NATIONAL_FAIL_ADD) {
                if (l < 1 + ROSE_ADDR_LEN)
                    return -1;
                memcpy(&facilities->fail_addr, p + 3, ROSE_ADDR_LEN);
            }
            else if (*p == FAC_NATIONAL_DIGIS) {
                if (l % AX25_ADDR_LEN)
                    return -1;
                fac_national_digis_received = 1;
                facilities->source_ndigis = 0;
                facilities->dest_ndigis   = 0;
                for (pt = p + 2, lg = 0 ; lg < l ; pt += AX25_ADDR_LEN, lg += AX25_ADDR_LEN) {
                    if (pt[6] & AX25_HBIT) {
                        if (facilities->dest_ndigis >= ROSE_MAX_DIGIS)
                            return -1;
                        memcpy(&facilities->dest_digis[facilities->dest_ndigis++], pt, AX25_ADDR_LEN);
                    } else {
                        if (facilities->source_ndigis >= ROSE_MAX_DIGIS)
                            return -1;
                        memcpy(&facilities->source_digis[facilities->source_ndigis++], pt, AX25_ADDR_LEN);
                    }
                }
            }
            p   += l + 2;
            n   += l + 2;
            len -= l + 2;
            break;
        }
    } while (*p != 0x00 && len > 0);

    return n;
}

static int rose_parse_ccitt(unsigned char *p, struct rose_facilities_struct *facilities, int len)
{
    unsigned char l, n = 0;
    char callsign[11];

    do {
        switch (*p & 0xC0) {
        case 0x00:
            if (len < 2)
                return -1;
            p   += 2;
            n   += 2;
            len -= 2;
            break;

        case 0x40:
            if (len < 3)
                return -1;
            p   += 3;
            n   += 3;
            len -= 3;
            break;

        case 0x80:
            if (len < 4)
                return -1;
            p   += 4;
            n   += 4;
            len -= 4;
            break;

        case 0xC0:
            if (len < 2)
                return -1;
            l = p[1];

            /* Prevent overflows*/
            if (l < 10 || l > 20)
                return -1;

            if (*p == FAC_CCITT_DEST_NSAP) {
                memcpy(&facilities->source_addr, p + 7, ROSE_ADDR_LEN);
                memcpy(callsign, p + 12,   l - 10);
                callsign[l - 10] = '\0';
                asc2ax(&facilities->source_call, callsign);
            }
            if (*p == FAC_CCITT_SRC_NSAP) {
                memcpy(&facilities->dest_addr, p + 7, ROSE_ADDR_LEN);
                memcpy(callsign, p + 12, l - 10);
                callsign[l - 10] = '\0';
                asc2ax(&facilities->dest_call, callsign);
            }
            p   += l + 2;
            n   += l + 2;
            len -= l + 2;
            break;
        }
    } while (*p != 0x00 && len > 0);

    return n;
}

int rose_parse_facilities(unsigned char *p, unsigned packet_len,
    struct rose_facilities_struct *facilities)
{
    int facilities_len, len;

    facilities_len = *p++;

    if (facilities_len == 0 || (unsigned int)facilities_len > packet_len)
        return 0;

    while (facilities_len >= 3 && *p == 0x00) {
        facilities_len--;
        p++;

        switch (*p) {
        case FAC_NATIONAL:      /* National */
            len = rose_parse_national(p + 1, facilities, facilities_len - 1);
            break;

        case FAC_CCITT:     /* CCITT */
            len = rose_parse_ccitt(p + 1, facilities, facilities_len - 1);
            break;

        default:
            printk(KERN_DEBUG "ROSE: rose_parse_facilities - unknown facilities family %02X\n", *p);
            len = 1;
            break;
        }

        if (len < 0)
            return 0;
        if (WARN_ON(len >= facilities_len))
            return 0;
        facilities_len -= len + 1;
        p += len + 1;
    }

    return facilities_len == 0;
}

static int rose_create_facilities(unsigned char *buffer, struct rose_sock *rose)
{
    unsigned char *p = buffer + 1;
    char *callsign;
    char buf[11];
    int len, nb;

    /* National Facilities */
    if (rose->rand != 0 || rose->source_ndigis == 1 || rose->dest_ndigis == 1) {
        *p++ = 0x00;
        *p++ = FAC_NATIONAL;

        if (rose->rand != 0) {
            *p++ = FAC_NATIONAL_RAND;
            *p++ = (rose->rand >> 8) & 0xFF;
            *p++ = (rose->rand >> 0) & 0xFF;
        }

        /* Sent before older facilities */
        if ((rose->source_ndigis > 0) || (rose->dest_ndigis > 0)) {
            int maxdigi = 0;
            *p++ = FAC_NATIONAL_DIGIS;
            *p++ = AX25_ADDR_LEN * (rose->source_ndigis + rose->dest_ndigis);
            for (nb = 0 ; nb < rose->source_ndigis ; nb++) {
                if (++maxdigi >= ROSE_MAX_DIGIS)
                    break;
                memcpy(p, &rose->source_digis[nb], AX25_ADDR_LEN);
                p[6] |= AX25_HBIT;
                p += AX25_ADDR_LEN;
            }
            for (nb = 0 ; nb < rose->dest_ndigis ; nb++) {
                if (++maxdigi >= ROSE_MAX_DIGIS)
                    break;
                memcpy(p, &rose->dest_digis[nb], AX25_ADDR_LEN);
                p[6] &= ~AX25_HBIT;
                p += AX25_ADDR_LEN;
            }
        }

        /* For compatibility */
        if (rose->source_ndigis > 0) {
            *p++ = FAC_NATIONAL_SRC_DIGI;
            *p++ = AX25_ADDR_LEN;
            memcpy(p, &rose->source_digis[0], AX25_ADDR_LEN);
            p   += AX25_ADDR_LEN;
        }

        /* For compatibility */
        if (rose->dest_ndigis > 0) {
            *p++ = FAC_NATIONAL_DEST_DIGI;
            *p++ = AX25_ADDR_LEN;
            memcpy(p, &rose->dest_digis[0], AX25_ADDR_LEN);
            p   += AX25_ADDR_LEN;
        }
    }

    *p++ = 0x00;
    *p++ = FAC_CCITT;

    *p++ = FAC_CCITT_DEST_NSAP;

    callsign = ax2asc(buf, &rose->dest_call);

    *p++ = strlen(callsign) + 10;
    *p++ = (strlen(callsign) + 9) * 2;      /* ??? */

    *p++ = 0x47; *p++ = 0x00; *p++ = 0x11;
    *p++ = ROSE_ADDR_LEN * 2;
    memcpy(p, &rose->dest_addr, ROSE_ADDR_LEN);
    p   += ROSE_ADDR_LEN;

    memcpy(p, callsign, strlen(callsign));
    p   += strlen(callsign);

    *p++ = FAC_CCITT_SRC_NSAP;

    callsign = ax2asc(buf, &rose->source_call);

    *p++ = strlen(callsign) + 10;
    *p++ = (strlen(callsign) + 9) * 2;      /* ??? */

    *p++ = 0x47; *p++ = 0x00; *p++ = 0x11;
    *p++ = ROSE_ADDR_LEN * 2;
    memcpy(p, &rose->source_addr, ROSE_ADDR_LEN);
    p   += ROSE_ADDR_LEN;

    memcpy(p, callsign, strlen(callsign));
    p   += strlen(callsign);

    len       = p - buffer;
    buffer[0] = len - 1;

    return len;
}

void rose_disconnect(struct sock *sk, int reason, int cause, int diagnostic)
{
    struct rose_sock *rose = rose_sk(sk);

    rose_stop_timer(sk);
    rose_stop_idletimer(sk);

    rose_clear_queues(sk);

    rose->lci   = 0;
    rose->state = ROSE_STATE_0;

    if (cause != -1)
        rose->cause = cause;

    if (diagnostic != -1)
        rose->diagnostic = diagnostic;

    sk->sk_state     = TCP_CLOSE;
    sk->sk_err       = reason;
    sk->sk_shutdown |= SEND_SHUTDOWN;

    if (!sock_flag(sk, SOCK_DEAD)) {
        sk->sk_state_change(sk);
        sock_set_flag(sk, SOCK_DEAD);
    }
}