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authorEric Dumazet <edumazet@google.com>2013-01-25 20:34:37 +0000
committerDavid S. Miller <davem@davemloft.net>2013-01-28 00:27:15 -0500
commitcef401de7be8c4e155c6746bfccf721a4fa5fab9 (patch)
treeaf082329bf0613ed9de5b9575e3f94f3f03b77ec /net/ipv4
parent61550022b9586972082904b80de26a464c558437 (diff)
downloadlinux-stericsson-cef401de7be8c4e155c6746bfccf721a4fa5fab9.tar.gz
net: fix possible wrong checksum generation
Pravin Shelar mentioned that GSO could potentially generate wrong TX checksum if skb has fragments that are overwritten by the user between the checksum computation and transmit. He suggested to linearize skbs but this extra copy can be avoided for normal tcp skbs cooked by tcp_sendmsg(). This patch introduces a new SKB_GSO_SHARED_FRAG flag, set in skb_shinfo(skb)->gso_type if at least one frag can be modified by the user. Typical sources of such possible overwrites are {vm}splice(), sendfile(), and macvtap/tun/virtio_net drivers. Tested: $ netperf -H 7.7.8.84 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.8.84 () port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 3959.52 $ netperf -H 7.7.8.84 -t TCP_SENDFILE TCP SENDFILE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.8.84 () port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 3216.80 Performance of the SENDFILE is impacted by the extra allocation and copy, and because we use order-0 pages, while the TCP_STREAM uses bigger pages. Reported-by: Pravin Shelar <pshelar@nicira.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/af_inet.c1
-rw-r--r--net/ipv4/ip_gre.c4
-rw-r--r--net/ipv4/ipip.c4
-rw-r--r--net/ipv4/tcp.c3
-rw-r--r--net/ipv4/tcp_input.c4
-rw-r--r--net/ipv4/tcp_output.c4
6 files changed, 14 insertions, 6 deletions
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 4b7053919976..49ddca31c4da 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1306,6 +1306,7 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
SKB_GSO_UDP |
SKB_GSO_DODGY |
SKB_GSO_TCP_ECN |
+ SKB_GSO_SHARED_FRAG |
0)))
goto out;
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 303012adf9e6..af6be70821c4 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -738,7 +738,7 @@ drop:
static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
- const struct iphdr *old_iph = ip_hdr(skb);
+ const struct iphdr *old_iph;
const struct iphdr *tiph;
struct flowi4 fl4;
u8 tos;
@@ -756,6 +756,8 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
skb_checksum_help(skb))
goto tx_error;
+ old_iph = ip_hdr(skb);
+
if (dev->type == ARPHRD_ETHER)
IPCB(skb)->flags = 0;
diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index 191fc24a745a..8f024d41eefa 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -472,7 +472,7 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
__be16 df = tiph->frag_off;
struct rtable *rt; /* Route to the other host */
struct net_device *tdev; /* Device to other host */
- const struct iphdr *old_iph = ip_hdr(skb);
+ const struct iphdr *old_iph;
struct iphdr *iph; /* Our new IP header */
unsigned int max_headroom; /* The extra header space needed */
__be32 dst = tiph->daddr;
@@ -486,6 +486,8 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
skb_checksum_help(skb))
goto tx_error;
+ old_iph = ip_hdr(skb);
+
if (tos & 1)
tos = old_iph->tos;
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 52271947a471..3ec1f69c5ceb 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -896,6 +896,8 @@ new_segment:
skb_fill_page_desc(skb, i, page, offset, copy);
}
+ skb_shinfo(skb)->gso_type |= SKB_GSO_SHARED_FRAG;
+
skb->len += copy;
skb->data_len += copy;
skb->truesize += copy;
@@ -3032,6 +3034,7 @@ struct sk_buff *tcp_tso_segment(struct sk_buff *skb,
SKB_GSO_DODGY |
SKB_GSO_TCP_ECN |
SKB_GSO_TCPV6 |
+ SKB_GSO_SHARED_FRAG |
0) ||
!(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
goto out;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 0905997e5873..492c7cfe1453 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1240,13 +1240,13 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
*/
if (!skb_shinfo(prev)->gso_size) {
skb_shinfo(prev)->gso_size = mss;
- skb_shinfo(prev)->gso_type = sk->sk_gso_type;
+ skb_shinfo(prev)->gso_type |= sk->sk_gso_type;
}
/* CHECKME: To clear or not to clear? Mimics normal skb currently */
if (skb_shinfo(skb)->gso_segs <= 1) {
skb_shinfo(skb)->gso_size = 0;
- skb_shinfo(skb)->gso_type = 0;
+ skb_shinfo(skb)->gso_type &= SKB_GSO_SHARED_FRAG;
}
/* Difference in this won't matter, both ACKed by the same cumul. ACK */
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 667a6adfccf8..367e2ec01da1 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1133,6 +1133,7 @@ static void tcp_queue_skb(struct sock *sk, struct sk_buff *skb)
static void tcp_set_skb_tso_segs(const struct sock *sk, struct sk_buff *skb,
unsigned int mss_now)
{
+ skb_shinfo(skb)->gso_type &= SKB_GSO_SHARED_FRAG;
if (skb->len <= mss_now || !sk_can_gso(sk) ||
skb->ip_summed == CHECKSUM_NONE) {
/* Avoid the costly divide in the normal
@@ -1140,11 +1141,10 @@ static void tcp_set_skb_tso_segs(const struct sock *sk, struct sk_buff *skb,
*/
skb_shinfo(skb)->gso_segs = 1;
skb_shinfo(skb)->gso_size = 0;
- skb_shinfo(skb)->gso_type = 0;
} else {
skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss_now);
skb_shinfo(skb)->gso_size = mss_now;
- skb_shinfo(skb)->gso_type = sk->sk_gso_type;
+ skb_shinfo(skb)->gso_type |= sk->sk_gso_type;
}
}