net_sched: better precise estimation on packet length for untrusted packets (15e5a030) · Commits · 戴 / test

gso_segs were reset to zero when kernel receive packets from untrusted source. But we use this zero value to estimate precise packet len which is wrong. So this patch tries to estimate the correct gso_segs value before using it in qdisc_pkt_len_init(). Cc: Eric Dumazet <edumazet@google.com> Signed-off-by:

Jason Wang <jasowang@redhat.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/core/dev.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -2588,6 +2588,7 @@ static void qdisc_pkt_len_init(struct sk_buff *skb)
		*/
		if (shinfo->gso_size) {
		unsigned int hdr_len;
		u16 gso_segs = shinfo->gso_segs;

		/* mac layer + network layer */
		hdr_len = skb_transport_header(skb) - skb_mac_header(skb);
		@@ -2597,7 +2598,12 @@ static void qdisc_pkt_len_init(struct sk_buff *skb)
		hdr_len += tcp_hdrlen(skb);
		else
		hdr_len += sizeof(struct udphdr);
		qdisc_skb_cb(skb)->pkt_len += (shinfo->gso_segs - 1) * hdr_len;

		if (shinfo->gso_type & SKB_GSO_DODGY)
		gso_segs = DIV_ROUND_UP(skb->len - hdr_len,
		shinfo->gso_size);

		qdisc_skb_cb(skb)->pkt_len += (gso_segs - 1) * hdr_len;
		}
		}

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