> On Jul 29, 2016, at 11:49 AM, Ben Pfaff <b...@ovn.org> wrote:
>
> On Thu, Jul 28, 2016 at 11:26:12PM -0700, Justin Pettit wrote:
>> Rename "compose_nd" and "compose_na" to "compose_nd_ns" and
>> "compose_nd_na", respecively, to be clearer about their functionality.
>> This will also make it more consistent when we add Neighbor Discover
>> Router Solicitation/Advertisement compose functions.
>>
>> Also change the source and destination IPv6 addresses to take
>> "struct in6_addr" arguments, which are more common in the code base.
>>
>> Signed-off-by: Justin Pettit <jpet...@ovn.org>
>>
>> ---
>> v1->v2: Renamed functions to be consistent when adding more ND messages.
>> Fix alignment issues introduced with taking "struct in6_addr".
>
> I don't think that the ALIGNED_CASTs in compose_nd_ns() and
> compose_nd_na() are necessarily safe, on a system that lacks s6_addr32.
Thanks for catching that. From a library perspective, I think we should change
the arguments to packet_set_nd() to accept an in6_addr, but that's a more
invasive change than I want to make right now. I'll put it on my todo list.
How about the incremental below for now, though?
--Justin
-=-=-=-=-=-=-=-=-=-
diff --git a/lib/packets.c b/lib/packets.c
index b2316e7..d1e2a70 100644
--- a/lib/packets.c
+++ b/lib/packets.c
@@ -1371,8 +1371,11 @@ compose_nd_ns(struct dp_packet *b, const struct eth_addr
eth
nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
nd_opt->nd_opt_len = 1;
- packet_set_nd(b, ALIGNED_CAST(ovs_be32 *, ipv6_dst->s6_addr),
- eth_src, eth_addr_zero);
+ /* Copy target address to temp buffer to prevent misaligned access. */
+ ovs_be32 tbuf[4];
+ memcpy(tbuf, ipv6_dst->s6_addr, sizeof tbuf);
+ packet_set_nd(b, tbuf, eth_src, eth_addr_zero);
+
ns->icmph.icmp6_cksum = 0;
icmp_csum = packet_csum_pseudoheader6(dp_packet_l3(b));
ns->icmph.icmp6_cksum = csum_finish(csum_continue(icmp_csum, ns,
@@ -1402,8 +1405,11 @@ compose_nd_na(struct dp_packet *b,
nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
nd_opt->nd_opt_len = 1;
- packet_set_nd(b, ALIGNED_CAST(ovs_be32 *, ipv6_src->s6_addr),
- eth_addr_zero, eth_src);
+ /* Copy target address to temp buffer to prevent misaligned access. */
+ ovs_be32 tbuf[4];
+ memcpy(tbuf, ipv6_src->s6_addr, sizeof tbuf);
+ packet_set_nd(b, tbuf, eth_addr_zero, eth_src);
+
na->icmph.icmp6_cksum = 0;
icmp_csum = packet_csum_pseudoheader6(dp_packet_l3(b));
na->icmph.icmp6_cksum = csum_finish(csum_continue(icmp_csum, na,
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