Re: git: eb8dcdeac22d - main - jail: network epoch protection for IP address lists

From: Gleb Smirnoff <glebius_at_freebsd.org>
Date: Sun, 26 Dec 2021 19:14:24 UTC 
  Jessica,

On Sun, Dec 26, 2021 at 07:07:06PM +0000, Jessica Clarke wrote:
J> > +struct prison_ip {
J> > +	struct epoch_context ctx;
J> > +	uint32_t	ips;
J> > +#ifdef FUTURE_C
J> > +	union {
J> > +		struct in_addr pr_ip4[];
J> > +		struct in6_addr pr_ip6[];
J> > +	};
J> > +#else /* No future C :( */
J> > +#define	PR_IP(pip, i)	((const char *)((pip) + 1) + pr_families[af].size * (i))
J> > +#define	PR_IPD(pip, i)	((char *)((pip) + 1) + pr_families[af].size * (i))
J> > +#endif
J> > +};
J> 
J> You can make this work with a prison_ip base and prison_ipv[46] derived
J> structs.
J> 
J> As it stands this is quite gross, you’re assuming things about
J> alignment, and don’t even have a flexible char[] at the end to
J> represent the extra data.

Will adding char [] to the end be sufficient to guarantee proper alignment?

Using prison_ipv[46] derived structs won't work as most functions are now
made protocol independent.

-- 
Gleb Smirnoff