[PATCH 3.19 003/177] pktgen: fix UDP checksum computation

[Greg Kroah-Hartman]

3.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>

[ Upstream commit 7744b5f3693cc06695cb9d6667671c790282730f ]

This patch fixes two issues in UDP checksum computation in pktgen.

First, the pseudo-header uses the source and destination IP
addresses. Currently, the ports are used for IPv4.

Second, the UDP checksum covers both header and data.  So we need to
generate the data earlier (move pktgen_finalize_skb up), and compute
the checksum for UDP header + data.

Fixes: c26bf4a51308c ("pktgen: Add UDPCSUM flag to support UDP checksums")
Signed-off-by: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>
Acked-by: Thomas Graf <tgraf@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/core/pktgen.c |   16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -2842,25 +2842,25 @@ static struct sk_buff *fill_packet_ipv4(
 	skb->dev = odev;
 	skb->pkt_type = PACKET_HOST;
 
+	pktgen_finalize_skb(pkt_dev, skb, datalen);
+
 	if (!(pkt_dev->flags & F_UDPCSUM)) {
 		skb->ip_summed = CHECKSUM_NONE;
 	} else if (odev->features & NETIF_F_V4_CSUM) {
 		skb->ip_summed = CHECKSUM_PARTIAL;
 		skb->csum = 0;
-		udp4_hwcsum(skb, udph->source, udph->dest);
+		udp4_hwcsum(skb, iph->saddr, iph->daddr);
 	} else {
-		__wsum csum = udp_csum(skb);
+		__wsum csum = skb_checksum(skb, skb_transport_offset(skb), datalen + 8, 0);
 
 		/* add protocol-dependent pseudo-header */
-		udph->check = csum_tcpudp_magic(udph->source, udph->dest,
+		udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
 						datalen + 8, IPPROTO_UDP, csum);
 
 		if (udph->check == 0)
 			udph->check = CSUM_MANGLED_0;
 	}
 
-	pktgen_finalize_skb(pkt_dev, skb, datalen);
-
 #ifdef CONFIG_XFRM
 	if (!process_ipsec(pkt_dev, skb, protocol))
 		return NULL;
@@ -2976,6 +2976,8 @@ static struct sk_buff *fill_packet_ipv6(
 	skb->dev = odev;
 	skb->pkt_type = PACKET_HOST;
 
+	pktgen_finalize_skb(pkt_dev, skb, datalen);
+
 	if (!(pkt_dev->flags & F_UDPCSUM)) {
 		skb->ip_summed = CHECKSUM_NONE;
 	} else if (odev->features & NETIF_F_V6_CSUM) {
@@ -2984,7 +2986,7 @@ static struct sk_buff *fill_packet_ipv6(
 		skb->csum_offset = offsetof(struct udphdr, check);
 		udph->check = ~csum_ipv6_magic(&iph->saddr, &iph->daddr, udplen, IPPROTO_UDP, 0);
 	} else {
-		__wsum csum = udp_csum(skb);
+		__wsum csum = skb_checksum(skb, skb_transport_offset(skb), udplen, 0);
 
 		/* add protocol-dependent pseudo-header */
 		udph->check = csum_ipv6_magic(&iph->saddr, &iph->daddr, udplen, IPPROTO_UDP, csum);
@@ -2993,8 +2995,6 @@ static struct sk_buff *fill_packet_ipv6(
 			udph->check = CSUM_MANGLED_0;
 	}
 
-	pktgen_finalize_skb(pkt_dev, skb, datalen);
-
 	return skb;
 }
 


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