Re: [PATCH] flow-dissector: Fix alignment issue in __skb_flow_get_ports

From: David Miller <davem@davemloft.net>
Date: Fri, 10 Oct 2014 14:15:59 -0400 (EDT)

Your original code works because you do things like "byte[12] & 0xf0" to
extract these fields.

Changing that th->doff sequence to instead be:

		const u8 *bp;
		u8 buf[13];

		bp = __skb_header_pointer(skb, poff, sizeof(buf),
					  data, hlen, &buf);
		if (!bp)
			return poff;

		poff += max_t(u32, sizeof(struct tcphdr), (bp[12] & 0xf0) >> 2);
		break;

on top of your v3 patch works for me.

Please double-check my calculations.