On Mon, May 21, 2018 at 10:35:58PM +0200, Toke Høiland-Jørgensen wrote:
> +static u32 cake_overhead(struct cake_sched_data *q, const struct sk_buff
> *skb)
> +{
> + const struct skb_shared_info *shinfo = skb_shinfo(skb);
> + unsigned int hdr_len, last_len = 0;
> + u32 off = skb_network_offset(skb);
> + u32 len = qdisc_pkt_len(skb);
> + u16 segs = 1;
> +
> + q->avg_netoff = cake_ewma(q->avg_netoff, off << 16, 8);
> +
> + if (!shinfo->gso_size)
> + return cake_calc_overhead(q, len, off);
> +
> + /* borrowed from qdisc_pkt_len_init() */
> + hdr_len = skb_transport_header(skb) - skb_mac_header(skb);
> +
> + /* + transport layer */
> + if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 |
> + SKB_GSO_TCPV6))) {
> + const struct tcphdr *th;
> + struct tcphdr _tcphdr;
> +
> + th = skb_header_pointer(skb, skb_transport_offset(skb),
> + sizeof(_tcphdr), &_tcphdr);
> + if (likely(th))
> + hdr_len += __tcp_hdrlen(th);
> + } else {
I didn't see some code limiting GSO packets to just TCP or UDP. Is it
safe to assume that this packet is an UDP one, and not SCTP or ESP,
for example?
> + struct udphdr _udphdr;
> +
> + if (skb_header_pointer(skb, skb_transport_offset(skb),
> + sizeof(_udphdr), &_udphdr))
> + hdr_len += sizeof(struct udphdr);
> + }
> +
> + if (unlikely(shinfo->gso_type & SKB_GSO_DODGY))
> + segs = DIV_ROUND_UP(skb->len - hdr_len,
> + shinfo->gso_size);
> + else
> + segs = shinfo->gso_segs;
> +
> + len = shinfo->gso_size + hdr_len;
> + last_len = skb->len - shinfo->gso_size * (segs - 1);
> +
> + return (cake_calc_overhead(q, len, off) * (segs - 1) +
> + cake_calc_overhead(q, last_len, off));
> +}
> +
