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Diffstat (limited to 'net/sched/sch_cake.c')
-rw-r--r--net/sched/sch_cake.c41
1 files changed, 30 insertions, 11 deletions
diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c
index 60f8ae578819..cae006bef565 100644
--- a/net/sched/sch_cake.c
+++ b/net/sched/sch_cake.c
@@ -1553,30 +1553,49 @@ static unsigned int cake_drop(struct Qdisc *sch, struct sk_buff **to_free)
 
 static u8 cake_handle_diffserv(struct sk_buff *skb, u16 wash)
 {
-	int wlen = skb_network_offset(skb);
+	const int offset = skb_network_offset(skb);
+	u16 *buf, buf_;
 	u8 dscp;
 
 	switch (tc_skb_protocol(skb)) {
 	case htons(ETH_P_IP):
-		wlen += sizeof(struct iphdr);
-		if (!pskb_may_pull(skb, wlen) ||
-		    skb_try_make_writable(skb, wlen))
+		buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_);
+		if (unlikely(!buf))
 			return 0;
 
-		dscp = ipv4_get_dsfield(ip_hdr(skb)) >> 2;
-		if (wash && dscp)
+		/* ToS is in the second byte of iphdr */
+		dscp = ipv4_get_dsfield((struct iphdr *)buf) >> 2;
+
+		if (wash && dscp) {
+			const int wlen = offset + sizeof(struct iphdr);
+
+			if (!pskb_may_pull(skb, wlen) ||
+			    skb_try_make_writable(skb, wlen))
+				return 0;
+
 			ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, 0);
+		}
+
 		return dscp;
 
 	case htons(ETH_P_IPV6):
-		wlen += sizeof(struct ipv6hdr);
-		if (!pskb_may_pull(skb, wlen) ||
-		    skb_try_make_writable(skb, wlen))
+		buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_);
+		if (unlikely(!buf))
 			return 0;
 
-		dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> 2;
-		if (wash && dscp)
+		/* Traffic class is in the first and second bytes of ipv6hdr */
+		dscp = ipv6_get_dsfield((struct ipv6hdr *)buf) >> 2;
+
+		if (wash && dscp) {
+			const int wlen = offset + sizeof(struct ipv6hdr);
+
+			if (!pskb_may_pull(skb, wlen) ||
+			    skb_try_make_writable(skb, wlen))
+				return 0;
+
 			ipv6_change_dsfield(ipv6_hdr(skb), INET_ECN_MASK, 0);
+		}
+
 		return dscp;
 
 	case htons(ETH_P_ARP):