I am sorry, once again I've proved myself that it's a good thing that I am not a C developer and my skills are still not good enough to become one - thanks God for the high level languages :D

Of course the problem was in my function. This would be correct one:

int shm_copy_string(const char *original_string, int original_length, char **new_string) {
// allocate shared memory for new string
*new_string = (char *) shm_malloc(sizeof(char) * (original_length + 1));

if (*new_string == NULL) {
ERR("cannot allocate shm memory");
return -1;
}

// copy original string to new string
memcpy(*new_string, original_string, original_length);
// end new string with null character
(*new_string)[original_length] = '\0';

return 0;
}

First of all I was trying to copy more than I need (original_length + 1 instead of just original_length) and once again I was little confused with the pointers - double de-referencing always scares me ;-)

I am not sure if this will help somebody in the future but still I hope that anyone do the same error as me.

Have a nice day folks

On Thu, Apr 7, 2016 at 9:28 PM, Cockhootec Yahrabee <cockootec@gmail.com> wrote:

Hi guys!

I am trying to parse Call-ID from received message within my custom kamailio module but every time I parse it and persist it within shared memory of my module the kamailio sends back (to UA) SIP message with `{Call-ID-hex-stream}0d` instead of `{Call-ID-hex-stream}00`

So it seems that kamailio adds `CR` byte to Call-ID which I am parsing.

This is how I am parsing and persisting the Call-ID (in my opinion it's without affecting the original message but yet it seems that I am wrong):

First of all I parse Call-ID so I have `str` structure where the `call_id_str.s` is pointing to the begining of Call-ID within `sip_msg_t` structure and `call_id_str.len` has the length of that Call-ID.

Secondly I am trying to copy the string from received SIP message into my own structure (I mean copy not just point to it since I need it also when the message is gone). I've prepared this function:

int shm_copy_string(const char *original_string, int original_length, char **new_string) {
// allocate shared memory for new string
*new_string = (char *) shm_malloc(sizeof(char) * (original_length + 1));

if (*new_string == NULL) {
ERR("cannot allocate shm memory");
return -1;
}

// copy original string to new string
memcpy(new_string, &original_string, original_length);
// end new string with null character
(*new_string)[original_length] = '\0';

return 0;
}

I am calling this function within my module like this:

shm_copy_string(call_id_str.s, call_id_str.len, &call_id);

I don't manipulate with the pointer to original message in any way but still the message which kamailio sends back to my UA has that `CR` and it causes me big problems since UA cannot match the Call-ID.

Also weird is that when I skip copying of the Call-ID on Registration message it is not affected so UA can register but then when I am trying to call from UA to UA I am getting as a response for my INVITE the `407 Proxy Authentication Required` with malformed Call-ID.

Messages where I don't parse Call-ID are OK so the problem must be in this function.

Has anyone came across this issue? How-come response SIP message is affected when I didn't add anything to the message?

Thanks in advance for any help