[sr-dev] [kamailio/kamailio] dns_int_match_ip is broken (#2645)

### Description `dns_int_match_ip` is broken on 5.3.0 and above ### Troubleshooting #### Reproduction Try this dialplan: ``` if (dns_int_match_ip('dns.google', '8.8.8.8')) { xlog("L_INFO", "OK dns-ip match with dns_int_match_ip"); } else { xlog("L_ERR", "FAIL dns-ip match with dns_int_match_ip"); } if (dns_int_match_ip('100.100.100.100', '8.8.8.8')) { xlog("L_ERR", "FAIL dns_int_match_ip on 2 ip's"); } else { xlog("L_INFO", "OK dns_int_match_ip on 2 ip's"); } ``` On 5.2 releases, both checks succeed. On 5.3 and up, both fail. #### Debugging Data I've traced down the problem to `str2ip`. In 5.2, this is a `static inline` function defined in the header file `resolve.h`. Therefore, the returned `ip` structure is allocated *once per compilation unit* - ie. `ipops_mod.c` and `dns_cache.c` both have their own versions of the variable. Since fb75e90549a (5.3 and up) this function is defined in it's own compilation unit (`resolve.c`) and therefore shared by all callers. See: https://stackoverflow.com/questions/185624/static-variables-in-an-inlined-f… #### Log Messages n/a #### SIP Traffic n/a ### Possible Solutions - Have `ki_dns_sys_match_ip` make a local copy of the return value of `str2ip` - Move `str2ip` back to a header file - Refactor `str2ip` to take a pointer to an output struct ### Additional Information In 5.3, this is what happens: ``` # - ki_dns_int_match_ip will call str2ip on 8.8.8.8, filling the static variable # - resolvehost will call dns_a_get_he, which calls str2ip on dns.google.com, zeroing out the static variable # - (dns_cache_do_request will call str2ip on dns.google.com, zeroing out the static variable again) # - resolvehost queries DNS # - the resolved IP's will be compared to the zero'd out struct dns_int_match_ip('dns.google', '8.8.8.8') == false # - ki_dns_int_match_ip will call str2ip on 8.8.8.8, filling the static variable # - resolvehost will call dns_a_get_he, which calls str2ip on 100.100.100.100, overwriting the static variable # - the static variable will be compared to itself dns_int_match_ip('100.100.100.100', '8.8.8.8') == true ``` -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://github.com/kamailio/kamailio/issues/2645