Re: [PATCH 04/22] treewide: Use struct assignment instead of memcpy() for IP addresses

[David Gibson <david@gibson.dropbear.id.au>]

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On Sun, Aug 18, 2024 at 05:45:03PM +0200, Stefano Brivio wrote:
> On Fri, 16 Aug 2024 15:39:45 +1000
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > We rely on C11 already, so we can use clearer and more type-checkable
> > struct assignment instead of mempcy() for copying IP addresses around.
> > 
> > This exposes some "pointer could be const" warnings from cppcheck, so
> > address those too.
> > 
> > Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> > ---
> >  conf.c   | 12 ++++++------
> >  dhcpv6.c | 10 ++++++----
> >  2 files changed, 12 insertions(+), 10 deletions(-)
> > 
> > diff --git a/conf.c b/conf.c
> > index 750fdc86..9b05afeb 100644
> > --- a/conf.c
> > +++ b/conf.c
> > @@ -389,14 +389,14 @@ static void add_dns6(struct ctx *c,
> >  	/* Guest or container can only access local addresses via redirect */
> >  	if (IN6_IS_ADDR_LOOPBACK(addr)) {
> >  		if (!c->no_map_gw) {
> > -			memcpy(*conf, &c->ip6.gw, sizeof(**conf));
> > +			**conf = c->ip6.gw;
> >  			(*conf)++;
> >  
> >  			if (IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_match))
> > -				memcpy(&c->ip6.dns_match, addr, sizeof(*addr));
> > +				c->ip6.dns_match = *addr;
> >  		}
> >  	} else {
> > -		memcpy(*conf, addr, sizeof(**conf));
> > +		**conf = *addr;
> >  		(*conf)++;
> >  	}
> >  
> > @@ -632,7 +632,7 @@ static unsigned int conf_ip4(unsigned int ifi,
> >  			ip4->prefix_len = 32;
> >  	}
> >  
> > -	memcpy(&ip4->addr_seen, &ip4->addr, sizeof(ip4->addr_seen));
> > +	ip4->addr_seen = ip4->addr;
> >  
> >  	if (MAC_IS_ZERO(mac)) {
> >  		int rc = nl_link_get_mac(nl_sock, ifi, mac);
> > @@ -693,8 +693,8 @@ static unsigned int conf_ip6(unsigned int ifi,
> >  		return 0;
> >  	}
> >  
> > -	memcpy(&ip6->addr_seen, &ip6->addr, sizeof(ip6->addr));
> > -	memcpy(&ip6->addr_ll_seen, &ip6->addr_ll, sizeof(ip6->addr_ll));
> > +	ip6->addr_seen = ip6->addr;
> > +	ip6->addr_ll_seen = ip6->addr_ll;
> >  
> >  	if (MAC_IS_ZERO(mac)) {
> >  		rc = nl_link_get_mac(nl_sock, ifi, mac);
> > diff --git a/dhcpv6.c b/dhcpv6.c
> > index bbed41dc..87b3c3eb 100644
> > --- a/dhcpv6.c
> > +++ b/dhcpv6.c
> > @@ -298,7 +298,8 @@ static struct opt_hdr *dhcpv6_ia_notonlink(const struct pool *p,
> >  {
> >  	char buf[INET6_ADDRSTRLEN];
> >  	struct in6_addr req_addr;
> > -	struct opt_hdr *ia, *h;
> > +	const struct opt_hdr *h;
> > +	struct opt_hdr *ia;
> >  	size_t offset;
> >  	int ia_type;
> >  
> > @@ -312,12 +313,13 @@ ia_ta:
> >  		offset += sizeof(struct opt_ia_na);
> >  
> >  		while ((h = dhcpv6_opt(p, &offset, OPT_IAAADR))) {
> > -			struct opt_ia_addr *opt_addr = (struct opt_ia_addr *)h;
> > +			const struct opt_ia_addr *opt_addr
> > +				= (const struct opt_ia_addr *)h;
> 
> Nit: the assignment could go on its own line, then?

Good point, done.

> >  			if (ntohs(h->l) != OPT_VSIZE(ia_addr))
> >  				return NULL;
> >  
> > -			memcpy(&req_addr, &opt_addr->addr, sizeof(req_addr));
> > +			req_addr = opt_addr->addr;
> >  			if (!IN6_ARE_ADDR_EQUAL(la, &req_addr)) {
> >  				info("DHCPv6: requested address %s not on link",
> >  				     inet_ntop(AF_INET6, &req_addr,
> > @@ -363,7 +365,7 @@ static size_t dhcpv6_dns_fill(const struct ctx *c, char *buf, int offset)
> >  			srv->hdr.l = 0;
> >  		}
> >  
> > -		memcpy(&srv->addr[i], &c->ip6.dns[i], sizeof(srv->addr[i]));
> > +		srv->addr[i] = c->ip6.dns[i];
> >  		srv->hdr.l += sizeof(srv->addr[i]);
> >  		offset += sizeof(srv->addr[i]);
> >  	}
> 
> I only reviewed up to this patch so far.
> 

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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