Re: [PATC] Fix to prevent AT-command interference

Hi MAtti

Great job. I was having this issue with my enfora modems.

This error was causing the modems to hung and kannel to drop the
connection an try to reconnect.

I've installed the patch and will monnitor the sistem.

Will let you know.

Regards

Alvaro


On Sat, 2008-11-15 at 11:03 +0200, Matti Ärmänen wrote:
> Hello,
> If a memory check is performed right after AT+CNMA-command, an error
> message is generated and modem connection is reopened.
> 
> Here is an example:
> 2008-09-28 17:57:59 [7962] [16] DEBUG: AT2[12]: <-- +CMT: ,20
> 2008-09-28 17:57:59 [7962] [16] DEBUG: AT2[12]: <-- ****DELETED****
> 2008-09-28 17:57:59 [7962] [16] DEBUG: AT2[12]: received message from
> SMSC: ****DELETED****
> 2008-09-28 17:57:59 [7962] [16] DEBUG: AT2[12]: Numeric sender
> (international) <****DELETED****>
> 2008-09-28 17:57:59 [7962] [16] DEBUG: AT2[12]: User data length read as (1)
> 2008-09-28 17:57:59 [7962] [16] DEBUG: AT2[12]: Udh decoding done len=1
> udhi=0 udhlen=0 udh=''
> 2008-09-28 17:57:59 [7962] [16] DEBUG: AT2[12]: --> AT+CNMA^M
> 2008-09-28 17:58:00 [7962] [16] DEBUG: AT2[12]: --> AT+CPMS?^M
> 2008-09-28 17:58:00 [7962] [16] DEBUG: AT2[12]: <-- OK
> 2008-09-28 17:58:00 [7962] [16] DEBUG: AT2[12]: no correct header for
> CPMS response.
> 2008-09-28 17:58:00 [7962] [16] DEBUG: AT2[12]: memory check error
> 2008-09-28 17:58:00 [7962] [16] INFO: AT2[12]: Closing device
> 2008-09-28 17:58:00 [7962] [16] ERROR: AT2[12]: Couldn't connect
> (retrying in 10 seconds).
> 
> This can be fixed, if after issuing the AT+CNMA-command, the OK-answer
> is waited before continuing. As the OK-answer is waited, the logic with
> "expect_extra_ok"-counter is no longer necessary.
> 
> We have run this in 3 kannel instances for 2 months without problems.
> 
> Regards,
> Matti Ärmänen
> 
> 
> plain text document attachment (patch.txt)
> --- smsc_at.c.orig      2008-09-28 18:37:38.000000000 +0300
> +++ smsc_at.c   2008-09-28 18:41:53.000000000 +0300
> @@ -749,7 +749,6 @@
>     Msg        *msg;
>     int len;
>     int cmgr_flag = 0;
> -    int expect_extra_ok = 0;
> 
>     time(&end_time);
>     if (timeout == 0)
> @@ -772,12 +771,8 @@
>                 goto end;
>             }
>             if (octstr_search(line, octstr_imm("OK"), 0) != -1) {
> -                if (!expect_extra_ok) {
> -                    ret = 0;
> -                    goto end;
> -                } else {
> -                    --expect_extra_ok;
> -                }
> +                ret = 0;
> +                goto end;
>             }
>             if ((gt_flag ) && (octstr_search(line, octstr_imm(">"), 0) != -1)) {
>                 ret = 1;
> @@ -847,8 +842,7 @@
> 
>                         if (!cmgr_flag) {
>                             if (privdata->phase2plus) {
> -                                at2_write_line(privdata, "AT+CNMA");
> -                                ++expect_extra_ok;
> +                                at2_send_modem_command(privdata, "AT+CNMA", 3, 0);
>                             }
>                         }