Re: PATCH: shared library support

Hello

wouldn't be possible to pas an argument to the ./configure to select
between static or dynamic building (or even both) ?

On Sun, Jan 09, 2005 at 02:11:43AM -0500, James Ralston wrote:
> qAttached is a patch for libnet 1.1.2.1 that adds support (via libtool)
> for building libnet as a shared library.
> 
> -    AC_DEFINE(HAVE_DLPI)
> +    AC_DEFINE(HAVE_DLPI, 1, [I don't know what this does.])

DLPI = Data Link Provider Interface
It is a device used ton inject packets at link layer under HPUX for
instance.

> +    AC_DEFINE(HAVE_SOCKADDR_SA_LEN, 1, [I don't know what this does.])

On some systems struct sockaddr does not have a sa_len field.
BTW, if someone has a pointer to an explanation on why it is prensent
on some system, and not on others, I'd like to have it.

>  *solaris*)
> -    AC_DEFINE(HAVE_SOLARIS)
> +    AC_DEFINE(HAVE_SOLARIS, 1, [I don't know what this does.])

It is defined for some particular Solaris stuff:
- getipnodebynap() instead of gethostbyname2()
- getipnodebyaddr() instead of gethostbyaddr()
- some device specific binding (in DLPI)

> -            AC_DEFINE_UNQUOTED(DLPI_DEV_PREFIX, "$dir")
> +            AC_DEFINE_UNQUOTED(DLPI_DEV_PREFIX, "$dir", [I don't know what this does.])

AFAIK DLPI is reachable through a device, usually placed in /dev, but
it can be placed somewhere else. This is to define to path to the dlpi
device.

>      case "`uname -r`" in
>      5.4)
> -        AC_DEFINE(STUPID_SOLARIS_CHECKSUM_BUG)
> +        AC_DEFINE(STUPID_SOLARIS_CHECKSUM_BUG, 1, [I don't know what this does.])
>          ;;
>      5.5*)
> -        AC_DEFINE(STUPID_SOLARIS_CHECKSUM_BUG)
> +        AC_DEFINE(STUPID_SOLARIS_CHECKSUM_BUG, 1, [I don't know what this does.])
>          ;;
>      5.8)
> -        AC_DEFINE(STUPID_SOLARIS_CHECKSUM_BUG)
> -    	AC_DEFINE(HAVE_SOLARIS_IPV6)
> +        AC_DEFINE(STUPID_SOLARIS_CHECKSUM_BUG, 1, [I don't know what this does.])
> +    	AC_DEFINE(HAVE_SOLARIS_IPV6, 1, [I don't know what this does.])
>          ;;
>      5.9)
> -        AC_DEFINE(STUPID_SOLARIS_CHECKSUM_BUG)
> -    	AC_DEFINE(HAVE_SOLARIS_IPV6)
> +        AC_DEFINE(STUPID_SOLARIS_CHECKSUM_BUG, 1, [I don't know what this does.])
> +    	AC_DEFINE(HAVE_SOLARIS_IPV6, 1, [I don't know what this does.])
>          ;;
>  
>      esac

STUPID_SOLARIS_CHECKSUM_BUG: on some old Solaris, TCP checksum are
poorly computed (see libnet_checksum.c):
#if (STUPID_SOLARIS_CHECKSUM_BUG)
            tcph_p->th_sum = tcph_p->th_off << 2;
            return (1);
#endif /* STUPID_SOLARIS_CHECKSUM_BUG */
There is something similar for HPUX11 too just below.

HAVE_SOLARIS_IPV6: IPv6 is not available on older Solaris, like 5.5 or
previous. This ensures that the solaris we are on do have IPv6.

>  *hpux11*)
> -    AC_DEFINE(HAVE_HPUX11)
> +    AC_DEFINE(HAVE_HPUX11, 1, [I don't know what this does.])

Also a "stupid bug" (quoting Mike ;), see in libnet_checksum.c

#if (HAVE_HPUX11)   
            if (l->injection_type != LIBNET_LINK)
            {
                /*
                 *  Similiar to the Solaris Checksum bug - but need to
                 *  add
                 *  the size of the TCP payload (only for raw
                 *  sockets).
                 */
                tcph_p->th_sum = (tcph_p->th_off << 2) +
                        (len - (tcph_p->th_off << 2));
                return (1); 
            }
#endif

Reading the code from libne_link_dlpi, it also seems HPUX made many
changes in its network link layer handling when reaching the version
11. Thus, these changes are used. For instance, writing use a specific
structure called dl_hp_rawdata_req_t.

> +     AC_DEFINE(NO_SNPRINTF, 1, [I don't know what this does.])

Not all system do define snprintf(). For those who dont, snprintf is
porrly replaced with sprintf() and the length field is ignored.



I hope this helps,

	Fred Raynal