[EMAIL PROTECTED] wrote:
Hi,
Why not just replace the lines
*(struct ip_addr2 *)&sipaddr = hdr->sipaddr;
*(struct ip_addr2 *)&dipaddr = hdr->dipaddr;
with
sipaddr = *(struct ip_addr *)&hdr->sipaddr;
dipaddr = *(struct ip_addr *)&hdr->dipaddr;
Because if hdr->sipaddr is unaligned and the architecture doesn't
support unaligned accesses, like many RISCs do, the result is undefined.
PS.
Haven't tested it, and dont now why one uses "struct ip_addr" and
"struct ip_addr2"
DS.
Don't know that either.
Cheers,
Pedro Alves
/Beach/
On 4/18/06, Pedro Alves <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>> wrote:
> This patch fixes this catched by gcc:
>
> $ make
> (...)/lwip/src/netif/etharp.c
> (...)/lwip/src/netif/etharp.c: In function 'etharp_arp_input':
> (...)/lwip/src/netif/etharp.c:505: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
> (...)/lwip/src/netif/etharp.c:506: warning: dereferencing type-punned
> pointer will break strict-aliasing rules
>
> We could also use memcpy here, but that seems overkill for copying 8
bytes.
>
> Cheers,
> Pedro Alves
>
> Index: src/netif/etharp.c
> ===================================================================
> RCS file: /sources/lwip/lwip/src/netif/etharp.c,v
> retrieving revision 1.94
> diff -u -r1.94 etharp.c
> --- src/netif/etharp.c 29 Mar 2006 13:16:40 -0000 1.94
> +++ src/netif/etharp.c 18 Apr 2006 10:41:47 -0000
> @@ -487,10 +487,11 @@
> }
>
> hdr = p->payload;
> -
> /* get aligned copies of addresses */
> - *(struct ip_addr2 *)&sipaddr = hdr->sipaddr;
> - *(struct ip_addr2 *)&dipaddr = hdr->dipaddr;
> + for(i=0; i<sizeof(hdr->sipaddr); i++)
> + ((u8_t*)&sipaddr)[i] = ((u8_t*)&hdr->sipaddr)[i];
> + for(i=0; i<sizeof(hdr->dipaddr); i++)
> + ((u8_t*)&dipaddr)[i] = ((u8_t*)&hdr->dipaddr)[i];
>
> /* this interface is not configured? */
> if (netif->ip_addr.addr == 0) {
>
>
>
> _______________________________________________
> lwip-users mailing list
> [email protected] <mailto:[email protected]>
> http://lists.nongnu.org/mailman/listinfo/lwip-users
>
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