Re: [PATCH] libxt_TCPMSS.c: unbreak build without ipv6 after ea2a02f7

[Peter Korsgaard <jacmet@sunsite.dk>]

>>>>> "Jan" == Jan Engelhardt <jengelh@medozas.de> writes:

Hi,

 Jan> On Friday 2011-07-22 07:24, Peter Korsgaard wrote:
 >> ea2a02f7 (libxt_TCPMSS: use guided option parser) added an netinet/ip6.h
 >> include, which is not available on systems without ipv6.

 Jan> I can understand that some implementations omit symbols that are a 
 Jan> runtime dependency (such as in6addr_any) from the library, but structs 
 Jan> are for free, so what broken libc does forget those?

uClibc. It doesn't even install netinet/{ip6,icmp6}.h if ipv6 support
isn't enabled:

http://git.uclibc.org/uClibc/tree/Makefile.in#n249

 >> +#define IPHDRSIZE	20	/* sizeof(struct iphdr) */
 >> +#define IP6HDRSIZE	40	/* sizeof(struct ip6_hdr) */

 Jan> That would put a hard assumption on the implementation, which does
 Jan> not seem the right thing to do.

But those structs define the network format of ipv4 and ipv6 headers, so
they are not likely to change.

-- 
Bye, Peter Korsgaard