pktgen: Fix position of ip and udp header

skb_set_network_header() expects an offset based on the data pointer
whereas skb_tail_offset() also includes the headroom. This resulted
in the ip header being written in a wrong location.

Use return values of skb_put() directly and rely on skb->len to
set mac, network, and transport header.

Cc: Simon Horman <horms@verge.net.au>
Cc: Daniel Borkmann <dborkmann@redhat.com>
Assisted-by: Daniel Borkmann <dborkmann@redhat.com>
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Daniel Borkmann <dborkmann@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 27 deletions

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index d2ede89662be..303412d8332b 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -2642,7 +2642,6 @@ static struct sk_buff *fill_packet_ipv4(struct net_device *odev,
         __be16 *svlan_tci = NULL;                /* Encapsulates priority and SVLAN ID */
         __be16 *svlan_encapsulated_proto = NULL; /* packet type ID field (or len) for SVLAN tag */
         u16 queue_map;
-        unsigned long tail_offset;
 
         if (pkt_dev->nr_labels)
                 protocol = htons(ETH_P_MPLS_UC);
@@ -2709,20 +2708,15 @@ static struct sk_buff *fill_packet_ipv4(struct net_device *odev,
                 *vlan_encapsulated_proto = htons(ETH_P_IP);
         }
 
-        tail_offset = skb_tail_offset(skb);
-        if (tail_offset > 0xffff) {
-                kfree_skb(skb);
-                return NULL;
-        }
-        skb_set_network_header(skb, tail_offset);
-        skb->transport_header = skb->network_header + sizeof(struct iphdr);
-        skb_put(skb, sizeof(struct iphdr) + sizeof(struct udphdr));
+        skb_set_mac_header(skb, 0);
+        skb_set_network_header(skb, skb->len);
+        iph = (struct iphdr *) skb_put(skb, sizeof(struct iphdr));
+
+        skb_set_transport_header(skb, skb->len);
+        udph = (struct udphdr *) skb_put(skb, sizeof(struct udphdr));
         skb_set_queue_mapping(skb, queue_map);
         skb->priority = pkt_dev->skb_priority;
 
-        iph = ip_hdr(skb);
-        udph = udp_hdr(skb);
-
         memcpy(eth, pkt_dev->hh, 12);
         *(__be16 *) & eth[12] = protocol;
 
@@ -2752,8 +2746,6 @@ static struct sk_buff *fill_packet_ipv4(struct net_device *odev,
         iph->check = 0;
         iph->check = ip_fast_csum((void *)iph, iph->ihl);
         skb->protocol = protocol;
-        skb->mac_header = (skb->network_header - ETH_HLEN -
-                           pkt_dev->pkt_overhead);
         skb->dev = odev;
         skb->pkt_type = PACKET_HOST;
         pktgen_finalize_skb(pkt_dev, skb, datalen);
@@ -2781,7 +2773,6 @@ static struct sk_buff *fill_packet_ipv6(struct net_device *odev,
         __be16 *svlan_tci = NULL;                /* Encapsulates priority and SVLAN ID */
         __be16 *svlan_encapsulated_proto = NULL; /* packet type ID field (or len) for SVLAN tag */
         u16 queue_map;
-        unsigned long tail_offset;
 
         if (pkt_dev->nr_labels)
                 protocol = htons(ETH_P_MPLS_UC);
@@ -2829,18 +2820,14 @@ static struct sk_buff *fill_packet_ipv6(struct net_device *odev,
                 *vlan_encapsulated_proto = htons(ETH_P_IPV6);
         }
 
-        tail_offset = skb_tail_offset(skb);
-        if (tail_offset > 0xffff) {
-                kfree_skb(skb);
-                return NULL;
-        }
-        skb_set_network_header(skb, tail_offset);
-        skb->transport_header = skb->network_header + sizeof(struct ipv6hdr);
-        skb_put(skb, sizeof(struct ipv6hdr) + sizeof(struct udphdr));
+        skb_set_mac_header(skb, 0);
+        skb_set_network_header(skb, skb->len);
+        iph = (struct ipv6hdr *) skb_put(skb, sizeof(struct ipv6hdr));
+
+        skb_set_transport_header(skb, skb->len);
+        udph = (struct udphdr *) skb_put(skb, sizeof(struct udphdr));
         skb_set_queue_mapping(skb, queue_map);
         skb->priority = pkt_dev->skb_priority;
-        iph = ipv6_hdr(skb);
-        udph = udp_hdr(skb);
 
         memcpy(eth, pkt_dev->hh, 12);
         *(__be16 *) &eth[12] = protocol;
@@ -2875,8 +2862,6 @@ static struct sk_buff *fill_packet_ipv6(struct net_device *odev,
         iph->daddr = pkt_dev->cur_in6_daddr;
         iph->saddr = pkt_dev->cur_in6_saddr;
 
-        skb->mac_header = (skb->network_header - ETH_HLEN -
-                           pkt_dev->pkt_overhead);
         skb->protocol = protocol;
         skb->dev = odev;
         skb->pkt_type = PACKET_HOST;