On Sat, May 19, 2018 at 12:08:57AM +0200, Sven Eckelmann wrote:
On Dienstag, 15. Mai 2018 17:59:08 CEST Linus Lüssing wrote:
magic = skb_header_pointer(skb, offset, sizeof(_magic), &_magic);if (!magic || *magic != htonl(BATADV_DHCP_MAGIC))return -EINVAL;I just hear a neoraider cry [1] in the background because you've added a new potentially unaligned 4 byte access in the network packet parsing code.
[...]
+static __be32 *batadv_dat_dhcp_get_yiaddr(struct sk_buff *skb, __be32 *buffer) +{
unsigned int offset = skb_transport_offset(skb) + sizeof(struct udphdr);unsigned int len = sizeof(((struct batadv_dhcp_packet *)0)->yiaddr);offset += offsetof(struct batadv_dhcp_packet, yiaddr);return skb_header_pointer(skb, offset, len, buffer);+}
Same here
Hm, I guess there's nothing I could do about that unaligned access other than suppressing any potential warnings? I guess since DHCP ACKs are relatively rare compared to other traffic in fast path I think the performance impact should be negligible.
What was the magic command to check unaligned accesses during runtime again?
With the preceding "#pragma pack(2)" any warnings should be suppressed already, shouldn't they?
Regards, Linus