ims_usrloc_scscf: bugfix Contct is removed when old Contct expires

[christoph-v]

in function unlink_contact_from_impu() (in file impurecord.c) an
assignment "=" is used instead of a comparision operator "==". This
leads to mess, when old contact expires.

Pre-Submission Checklist

• Commit message has the format required by CONTRIBUTING guide
• Commits are split per component (core, individual modules, libs, utils, ...)
• Each component has a single commit (if not, squash them into one commit)
• No commits to README files for modules (changes must be done to docbook files
  in doc/ subfolder, the README file is autogenerated)

Type Of Change

• Small bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds new functionality)
• Breaking change (fix or feature that would change existing functionality)

Checklist:

• PR should be backported to stable branches
• Tested changes locally versus release 5.1.0
• Related to issue #XXXX (replace XXXX with an open issue number)

Description

This is the pull request for branch 5.1, which has been created by "cherry-pick" from the original commit

[miconda]

Thanks!

[thulasizwe-n]

Hi @christoph-v
Good fix...i see it's revealing another two potential issues on remove_impucontact_from_list same file (impurecord.c); 1) tail->next is not nullified on removing last impucontact--hence second last will still point to the "just-removed" impucontact
2) contact removal in mid list seems to have swapped fields on both sides of equal sign
Please see below possible fix:

int remove_impucontact_from_list(impurecord_t* impu, impu_contact_t impucontact) {
ucontact_t contact = impucontact->contact;

    if (/*contact - removed*/ impucontact == impu->linked_contacts.head /*->contact - removed */) {
            LM_DBG("deleting head\n");
            impu->linked_contacts.head = impu->linked_contacts.head->next;              
    } else if (/*contact*/ impucontact== impu->linked_contacts.tail/*->contact*/) {     
            LM_DBG("deleting tail prev %p next %p\n",impu->linked_contacts.tail->prev, impu->linked_contacts.tail->next);
            impu->linked_contacts.tail = impu->linked_contacts.tail->prev;              
            impu->linked_contacts.tail->next = 0; /* Nullified end of list*/
    } else {                                                                            
            LM_DBG("deleting mid list prev %p next %p\n", impucontact->prev, impucontact->next);
            impucontact->prev->next = impucontact->next;
            /*impucontact->prev = impucontact->next->prev; removed ---- seems to be small swap-around error*/                      
            impucontact->next->prev = impucontact->prev;  /* Added */
    }                                                                                           
    impu->linked_contacts.numcontacts--;                                                
    if (impucontact->contact->is_3gpp)
            impu->linked_contacts.num3gppcontacts--;
    LM_DBG("REMOVED impu_contact %p for contact %p\n",impucontact, contact);            
    shm_free(impucontact);                                                                      
    return 0;                                                                           

}

[christoph-v]

Hi @thulasizwe-n Thank you for the hint.

We will issue a pull request for this additional issue within the next few days, @miconda OK?