I observed that the inline function suip2a() (ip_addr.h) contains a silly bug and therefor does not work for IPv6 conversions. This silly bug is preventing sip_trace() to work in the onsend_route block for IPv6 sip messages. Rem.: The function suip2a() is used only by the siptrace module.

Test background (just for understanding the use case): - using kamailio 4.1.3 (with an additional patch to let onsend_route be called also for replies taken from kamailio 4.2.x) - kamailio is used as loadbalancer in stateless mode (using forward() only) - sip tracing is used by explictly calling sip_trace() in onsend_route, route and onreply routing block to be able to implement an interface specific sip tracing (no SIP transaction based sip tracing is applied by using the siptrace's trace_flag)

The silly bug:

In suip2a() the function ip6tosbuf() is called with an odd buffer length argument of value "sizeof(buf)-4" which is equal to "IP6_MAX_STR_SIZE -1". ip6tosbuf() however needs at least a buffer length of IP6_MAX_STR_SIZE (otherwise it returns immediately without writing anything into the buffer). So regarding IPv6 adresses the ascii output of suip2a() is alway an empty IPv6 reference ([]).

``` static inline int ip6tosbuf(unsigned char* ip6, char* buff, int len) { int offset; register unsigned char a,b,c; register unsigned char d; register unsigned short hex4; int r; #define HEXDIG(x) (((x)>=10)?(x)-10+'A':(x)+'0') offset=0; if (unlikely(len<IP6_MAX_STR_SIZE)) return 0; ... }

#define SUIP2A_MAX_STR_SIZE (IP6_MAX_STR_SIZE + 2 /* [] */ + 1 /* \0 */) /* returns an asciiz string containing the ip * (<ipv4_addr> or [<ipv6_addr>]) */ static inline char* suip2a(union sockaddr_union* su, int su_len) { static char buf[SUIP2A_MAX_STR_SIZE]; int offs;

if (unlikely(su->s.sa_family==AF_INET6)){ if (unlikely(su_len<sizeof(su->sin6))) return "<addr. error>"; buf[0]='['; offs=1+ip6tosbuf((unsigned char*)su->sin6.sin6_addr.s6_addr, &buf[1], sizeof(buf)-4); buf[offs]=']'; offs++; }else if (unlikely(su_len<sizeof(su->sin))) return "<addr. error>"; else offs=ip4tosbuf((unsigned char*)&su->sin.sin_addr, buf, sizeof(buf)-2); buf[offs]=0; return buf; } ```

A possible verfied patch looks like this (using this patch sip_trace() is working now as expected in this use case). ``` --- ip_addr.h 2014-04-24 12:02:35.000000000 +0200 +++ ip_addr.h 2015-10-22 18:48:40.553177206 +0200 @@ -737,14 +737,14 @@ return "<addr. error>"; buf[0]='['; offs=1+ip6tosbuf((unsigned char*)su->sin6.sin6_addr.s6_addr, &buf[1], - sizeof(buf)-4); + IP6_MAX_STR_SIZE); buf[offs]=']'; offs++; }else if (unlikely(su_len<sizeof(su->sin))) return "<addr. error>"; else - offs=ip4tosbuf((unsigned char*)&su->sin.sin_addr, buf, sizeof(buf)-2); + offs=ip4tosbuf((unsigned char*)&su->sin.sin_addr, buf, IP4_MAX_STR_SIZE); buf[offs]=0; return buf; }

```

--- Reply to this email directly or view it on GitHub: https://github.com/kamailio/kamailio/issues/379