smsc_at.c

主要包括sms网关和wap网关实现说明和源码

    type = octstr_get_char(data, 1) & 3;

    switch (type) {

        case AT_DELIVER_SM:
            msg = at2_pdu_decode_deliver_sm(data, privdata);
            break;
        case AT_STATUS_REPORT_SM:
            msg = at2_pdu_decode_report_sm(data, privdata);
            break;

            /* Add other message types here: */
    }

    return msg;
}


static Msg *at2_pdu_decode_deliver_sm(Octstr *data, PrivAT2data *privdata)
{
    int len, pos, i, ntype;
    int udhi, dcs, udhlen, pid;
    Octstr *origin = NULL;
    Octstr *udh = NULL;
    Octstr *text = NULL, *tmpstr;
    Octstr *pdu = NULL;
    Msg *message = NULL;
    struct universaltime mtime; /* time structure */
    long stime; /* time in seconds */
    int timezone; /* timezone in 15 minutes jumps from GMT */

    /* 
     * Note: some parts of the PDU are not decoded because they are
     * not needed for the Msg type. 
     */

    /* convert the pdu to binary format for ease of processing */
    pdu = at2_convertpdu(data);

    /* UDH Indicator */
    udhi = (octstr_get_char(pdu, 0) & 64) >> 6;

    /* originating address */
    len = octstr_get_char(pdu, 1);
    if (len > 20) /* maximum valid number of semi-octets in Address-Value field */
        goto msg_error;
    ntype = octstr_get_char(pdu, 2);

    pos = 3;
    if ((ntype & 0xD0) == 0xD0) {
        /* Alphanumeric sender */
        origin = octstr_create("");
        tmpstr = octstr_copy(pdu, 3, len);
        at2_decode7bituncompressed(tmpstr, (((len - 1) * 4 - 3) / 7) + 1, origin, 0);
        octstr_destroy(tmpstr);
        debug("bb.smsc.at2", 0, "AT2[%s]: Alphanumeric sender <%s>", 
              octstr_get_cstr(privdata->name), octstr_get_cstr(origin));
        pos += (len + 1) / 2;
    } else {
        origin = octstr_create("");
        if ((ntype & 0x90) == 0x90) {
            /* International number */
            octstr_append_char(origin, '+');
        }
        for (i = 0; i < len; i += 2, pos++) {
            octstr_append_char(origin, (octstr_get_char(pdu, pos) & 15) + 48);
            if (i + 1 < len)
                octstr_append_char(origin, (octstr_get_char(pdu, pos) >> 4) + 48);
        }
        debug("bb.smsc.at2", 0, "AT2[%s]: Numeric sender %s <%s>", 
              octstr_get_cstr(privdata->name), ((ntype & 0x90) == 0x90 ? "(international)" : ""), 
              octstr_get_cstr(origin));
    }

    if (pos > octstr_len(pdu))
        goto msg_error;

    /* PID */
    pid = octstr_get_char(pdu, pos);
    pos++;

    /* DCS */
    dcs = octstr_get_char(pdu, pos);
    pos++;

    /* get the timestamp */
    mtime.year = swap_nibbles(octstr_get_char(pdu, pos));
    pos++;
    mtime.year += (mtime.year < 70 ? 2000 : 1900);
    mtime.month = swap_nibbles(octstr_get_char(pdu, pos));
    mtime.month--;    
    pos++;
    mtime.day = swap_nibbles(octstr_get_char(pdu, pos));
    pos++;
    mtime.hour = swap_nibbles(octstr_get_char(pdu, pos));
    pos++;
    mtime.minute = swap_nibbles(octstr_get_char(pdu, pos));
    pos++;
    mtime.second = swap_nibbles(octstr_get_char(pdu, pos));
    pos++;

    /* 
     * time zone: 
     *
     * time zone is "swapped nibble", with the MSB as the sign (1 is negative).  
     */
    timezone = swap_nibbles(octstr_get_char(pdu, pos));
    pos++;
    timezone = ((timezone >> 7) ? -1 : 1) * (timezone & 127);
    /* 
     * Ok, that was the time zone as read from the PDU. Now how to interpert it? 
     * All the handsets I tested send the timestamp of their local time and the 
     * timezone as GMT+0. I assume that the timestamp is the handset's local time, 
     * so we need to apply the timezone in reverse to get GM time: 
     */

    /* 
     * time in PDU is handset's local time and timezone is handset's time zone 
     * difference from GMT 
     */
    mtime.hour -= timezone / 4;
    mtime.minute -= 15 * (timezone % 4);

    stime = date_convert_universal(&mtime);

    /* get data length
     * XXX: Is it allowed to have length = 0 ??? (alex)
     */
    len = octstr_get_char(pdu, pos);
    pos++;

    debug("bb.smsc.at2", 0, "AT2[%s]: User data length read as (%d)", 
          octstr_get_cstr(privdata->name), len);

    /* if there is a UDH */
    udhlen = 0;
    if (udhi && len > 0) {
        udhlen = octstr_get_char(pdu, pos);
        pos++;
        if (udhlen + 1 > len)
            goto msg_error;
        udh = octstr_copy(pdu, pos, udhlen);
        pos += udhlen;
        len -= udhlen + 1;
    } else if (len <= 0) /* len < 0 is impossible, but sure is sure */
        udhi = 0;

    debug("bb.smsc.at2", 0, "AT2[%s]: Udh decoding done len=%d udhi=%d udhlen=%d udh='%s'",
          octstr_get_cstr(privdata->name), len, udhi, udhlen, (udh ? octstr_get_cstr(udh) : ""));

    if (pos > octstr_len(pdu) || len < 0)
        goto msg_error;

    /* build the message */
    message = msg_create(sms);
    if (!dcs_to_fields(&message, dcs)) {
        /* XXX Should reject this message? */
        debug("bb.smsc.at2", 0, "AT2[%s]: Invalid DCS", octstr_get_cstr(privdata->name));
        dcs_to_fields(&message, 0);
    }

    message->sms.pid = pid;

    /* deal with the user data -- 7 or 8 bit encoded */
    tmpstr = octstr_copy(pdu, pos, len);
    if (message->sms.coding == DC_8BIT || message->sms.coding == DC_UCS2) {
        text = octstr_duplicate(tmpstr);
    } else {
        int offset = 0;
        text = octstr_create("");
        if (udhi && message->sms.coding == DC_7BIT) {
            int nbits;
            nbits = (udhlen + 1) * 8;
            /* fill bits for UDH to septet boundary */
            offset = (((nbits / 7) + 1) * 7 - nbits) % 7;     
        }
        at2_decode7bituncompressed(tmpstr, len, text, offset);
    }

    message->sms.sender = origin;
    if (octstr_len(privdata->my_number)) {
        message->sms.receiver = octstr_duplicate(privdata->my_number);
    } else {
        /* Put a dummy address in the receiver for now (SMSC requires one) */
        message->sms.receiver = octstr_create_from_data("1234", 4);
    }
    if (udhi) {
        message->sms.udhdata = udh;
    }
    message->sms.msgdata = text;
    message->sms.time = stime;

    /* cleanup */
    octstr_destroy(pdu);
    octstr_destroy(tmpstr);

    return message;
    
msg_error:
    error(1, "AT2[%s]: Invalid DELIVER-SMS pdu!", octstr_get_cstr(privdata->name));
    O_DESTROY(udh);
    O_DESTROY(origin);
    O_DESTROY(text);
    O_DESTROY(pdu);
    return NULL;
}


static Msg *at2_pdu_decode_report_sm(Octstr *data, PrivAT2data *privdata)
{
    Msg *dlrmsg = NULL;
    Octstr *pdu, *msg_id, *tmpstr = NULL, *receiver = NULL;
    int type, tp_mr, len, ntype, pos;

    /*
     * parse the PDU.
     */

    /* convert the pdu to binary format for ease of processing */
    pdu = at2_convertpdu(data);

    /* Message reference */
    tp_mr = octstr_get_char(pdu, 1);
    msg_id = octstr_format("%d", tp_mr);
    debug("bb.smsc.at2", 0, "AT2[%s]: got STATUS-REPORT for message <%d>:", 
          octstr_get_cstr(privdata->name), tp_mr);
    
    /* reciver address */
    len = octstr_get_char(pdu, 2);
    ntype = octstr_get_char(pdu, 3);

    pos = 4;
    if ((ntype & 0xD0) == 0xD0) {
        /* Alphanumeric sender */
        receiver = octstr_create("");
        tmpstr = octstr_copy(pdu, pos, (len + 1) / 2);
        at2_decode7bituncompressed(tmpstr, (((len - 1) * 4 - 3) / 7) + 1, receiver, 0);
        octstr_destroy(tmpstr);
        debug("bb.smsc.at2", 0, "AT2[%s]: Alphanumeric receiver <%s>",
              octstr_get_cstr(privdata->name), octstr_get_cstr(receiver));
        pos += (len + 1) / 2;
    } else {
        int i;
        receiver = octstr_create("");
        if ((ntype & 0x90) == 0x90) {
            /* International number */
            octstr_append_char(receiver, '+');
        }
        for (i = 0; i < len; i += 2, pos++) {
            octstr_append_char(receiver, (octstr_get_char(pdu, pos) & 15) + 48);
            if (i + 1 < len)
                octstr_append_char(receiver, (octstr_get_char(pdu, pos) >> 4) + 48);
        }
        debug("bb.smsc.at2", 0, "AT2[%s]: Numeric receiver %s <%s>",
              octstr_get_cstr(privdata->name), ((ntype & 0x90) == 0x90 ? "(international)" : ""),
              octstr_get_cstr(receiver));
    }

    pos += 14; /* skip time stamps for now */

    if ((type = octstr_get_char(pdu, pos)) == -1 ) {
        error(1, "AT2[%s]: STATUS-REPORT pdu too short to have TP-Status field !",
              octstr_get_cstr(privdata->name));
        goto error;
    }

	/* Check DLR type:
	 * 3GPP TS 23.040 defines this a bit mapped field with lots of options
	 * most of which are not really intersting to us, as we are only interested
	 * in one of three conditions : failed, held in SC for delivery later, or delivered successfuly
	 * and here's how I suggest to test it (read the 3GPP reference for further detailes) -
	 * we'll test the 6th and 5th bits (7th bit when set making all other values 'reseved' so I want to test it).
	 */
    type = type & 0xE0; /* filter out everything but the 7th, 6th and 5th bits */
    switch (type) {
        case 0x00:
            /* 0 0 : success class */
            type = DLR_SUCCESS;
            tmpstr = octstr_create("Success");
            break;
        case 0x20:
            /* 0 1 : buffered class (temporary error) */
            type = DLR_BUFFERED;
            tmpstr = octstr_create("Buffered");
            break;
        case 0x40:
        case 0x60:
        default:
            /* 1 0 : failed class */
            /* 1 1 : failed class (actually, temporary error but timed out) */
            /* and any other value (can't think of any) is considered failure */
            type = DLR_FAIL;
            tmpstr = octstr_create("Failed");
            break;
    }
    /* Actually, the above implementation is not correct, as the reference 
     * says that implementations should consider any "reserved" values to be 
     * "failure", but most reserved values fall into one of the three 
     * categories. It will catch "reserved" values where the first 3 MSBits 
     * are not set as "Success" which may not be correct. */

    if ((dlrmsg = dlr_find(privdata->conn->id, msg_id, receiver, type)) == NULL) {
        debug("bb.smsc.at2", 1, "AT2[%s]: Received delivery notification but can't find that ID in the DLR storage",
              octstr_get_cstr(privdata->name));
	    goto error;
    }

    /* Beware DLR URL is now in msg->sms.dlr_url given by dlr_find() */
    dlrmsg->sms.msgdata = octstr_duplicate(tmpstr);
	
error:
    O_DESTROY(tmpstr);
    O_DESTROY(pdu);
    O_DESTROY(receiver);
    O_DESTROY(msg_id);
    return dlrmsg;
}

static Octstr *at2_convertpdu(Octstr *pdutext)
{
    Octstr *pdu;
    int i;
    int len = octstr_len(pdutext);

    pdu = octstr_create("");
    for (i = 0; i < len; i += 2) {
        octstr_append_char(pdu, at2_hexchar(octstr_get_char(pdutext, i)) * 16
                           + at2_hexchar(octstr_get_char(pdutext, i + 1)));
    }
    return pdu;
}


static int at2_rmask[8] = { 0, 1, 3, 7, 15, 31, 63, 127 };
static int at2_lmask[8] = { 0, 128, 192, 224, 240, 248, 252, 254 };

static void at2_decode7bituncompressed(Octstr *input, int len, Octstr *decoded, int offset)
{
    unsigned char septet, octet, prevoctet;
    int i;
    int r = 1;
    int c = 7;
    int pos = 0;

    /* Shift the buffer offset bits to the left */
    if (offset > 0) {
        unsigned char *ip;
        for (i = 0, ip = octstr_get_cstr(input); i < octstr_len(input); i++) {
            if (i == octstr_len(input) - 1)
                *ip = *ip >> offset;
            else
                *ip = (*ip >> offset) | (*(ip + 1) << (8 - offset));
            ip++;
        }
    }
    octet = octstr_get_char(input, pos);
    prevoctet = 0;
    for (i = 0; i < len; i++) {
        septet = ((octet & at2_rmask[c]) << (r - 1)) + prevoctet;
        octstr_append_char(decoded, septet);

        prevoctet = (octet & at2_lmask[r]) >> c;

        /* When r=7 we have a full character in prevoctet */
        if ((r == 7) && (i < len - 1)) {
            i++;
            octstr_append_char(decoded, prevoctet);
            prevoctet = 0;
        }

        r = (r > 6) ? 1 : r + 1;
        c = (c < 2) ? 7 : c - 1;

        pos++;
        octet = octstr_get_char(input, pos);
    }
    charset_gsm_to_latin1(decoded);
}


static void at2_send_messages(PrivAT2data *privdata)
{
    Msg *msg;

    do {
        if (privdata->modem->enable_mms && 
            gw_prioqueue_len(privdata->outgoing_queue) > 1)
            at2_send_modem_command(privdata, "AT+CMMS=2", 0, 0);

        if ((msg = gw_prioqueue_remove(privdata->outgoing_queue)))
            at2_send_one_message(privdata, msg);
    } while (msg);
}


static void at2_send_one_message(PrivAT2data *p