netdev - [PATCH net-next] sch_tbf: segment too big GSO packets

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 21 May 2013 11:16:46 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	David Miller <davem@...emloft.net>
Cc:	netdev <netdev@...r.kernel.org>, Jiri Pirko <jiri@...nulli.us>,
	Ben Hutchings <ben@...adent.org.uk>
Subject: [PATCH net-next] sch_tbf: segment too big GSO packets

From: Eric Dumazet <edumazet@...gle.com>

If a GSO packet has a length above tbf burst limit, the packet
is currently silently dropped.

Current way to handle this is to set the device in non GSO/TSO mode, or
setting high bursts, and its sub optimal.

We can actually segment too big GSO packets, and send individual
segments as tbf parameters allow, allowing for better interoperability.

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Cc: Ben Hutchings <ben@...adent.org.uk>
Cc: Jiri Pirko <jiri@...nulli.us>
Cc: Jamal Hadi Salim <jhs@...atatu.com>
---
 net/sched/sch_tbf.c |   47 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 45 insertions(+), 2 deletions(-)

diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index c8388f3..38008b0 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -116,14 +116,57 @@ struct tbf_sched_data {
 	struct qdisc_watchdog watchdog;	/* Watchdog timer */
 };
 
+
+/* GSO packet is too big, segment it so that tbf can transmit
+ * each segment in time
+ */
+static int tbf_segment(struct sk_buff *skb, struct Qdisc *sch)
+{
+	struct tbf_sched_data *q = qdisc_priv(sch);
+	struct sk_buff *segs, *nskb;
+	netdev_features_t features = netif_skb_features(skb);
+	int ret, nb;
+
+	segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
+
+	if (IS_ERR_OR_NULL(segs))
+		return qdisc_reshape_fail(skb, sch);
+
+	nb = 0;
+	while (segs) {
+		nskb = segs->next;
+		segs->next = NULL;
+		if (likely(segs->len <= q->max_size)) {
+			qdisc_skb_cb(segs)->pkt_len = segs->len;
+			ret = qdisc_enqueue(segs, q->qdisc);
+		} else {
+			ret = qdisc_reshape_fail(skb, sch);
+		}
+		if (ret != NET_XMIT_SUCCESS) {
+			if (net_xmit_drop_count(ret))
+				sch->qstats.drops++;
+		} else {
+			nb++;
+		}
+		segs = nskb;
+	}
+	sch->q.qlen += nb;
+	if (nb > 1)
+		qdisc_tree_decrease_qlen(sch, 1 - nb);
+	consume_skb(skb);
+	return nb > 0 ? NET_XMIT_SUCCESS : NET_XMIT_DROP;
+}
+
 static int tbf_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 {
 	struct tbf_sched_data *q = qdisc_priv(sch);
 	int ret;
 
-	if (qdisc_pkt_len(skb) > q->max_size)
+	if (qdisc_pkt_len(skb) > q->max_size) {
+		if (skb_is_gso(skb))
+			return tbf_segment(skb, sch);
 		return qdisc_reshape_fail(skb, sch);
-
+	}
 	ret = qdisc_enqueue(skb, q->qdisc);
 	if (ret != NET_XMIT_SUCCESS) {
 		if (net_xmit_drop_count(ret))


--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html