GSO: Add GSO type for fixed IPv4 ID

This patch adds support for TSO using IPv4 headers with a fixed IP ID
field.  This is meant to allow us to do a lossless GRO in the case of TCP
flows that use a fixed IP ID such as those that convert IPv6 header to IPv4
headers.

In addition I am adding a feature that for now I am referring to TSO with
IP ID mangling.  Basically when this flag is enabled the device has the
option to either output the flow with incrementing IP IDs or with a fixed
IP ID regardless of what the original IP ID ordering was.  This is useful
in cases where the DF bit is set and we do not care if the original IP ID
value is maintained.

Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alexander Duyck
2016-04-10 21:44:51 -04:00
committed by David S. Miller
parent 518f213ddd
commit cbc53e08a7
10 changed files with 63 additions and 24 deletions

View File

@@ -1195,10 +1195,10 @@ EXPORT_SYMBOL(inet_sk_rebuild_header);
static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
bool udpfrag = false, fixedid = false, encap;
struct sk_buff *segs = ERR_PTR(-EINVAL);
const struct net_offload *ops;
unsigned int offset = 0;
bool udpfrag, encap;
struct iphdr *iph;
int proto;
int nhoff;
@@ -1217,6 +1217,7 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
SKB_GSO_TCPV6 |
SKB_GSO_UDP_TUNNEL |
SKB_GSO_UDP_TUNNEL_CSUM |
SKB_GSO_TCP_FIXEDID |
SKB_GSO_TUNNEL_REMCSUM |
0)))
goto out;
@@ -1248,11 +1249,14 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
segs = ERR_PTR(-EPROTONOSUPPORT);
if (skb->encapsulation &&
skb_shinfo(skb)->gso_type & (SKB_GSO_SIT|SKB_GSO_IPIP))
udpfrag = proto == IPPROTO_UDP && encap;
else
udpfrag = proto == IPPROTO_UDP && !skb->encapsulation;
if (!skb->encapsulation || encap) {
udpfrag = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
fixedid = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TCP_FIXEDID);
/* fixed ID is invalid if DF bit is not set */
if (fixedid && !(iph->frag_off & htons(IP_DF)))
goto out;
}
ops = rcu_dereference(inet_offloads[proto]);
if (likely(ops && ops->callbacks.gso_segment))
@@ -1265,12 +1269,11 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
do {
iph = (struct iphdr *)(skb_mac_header(skb) + nhoff);
if (udpfrag) {
iph->id = htons(id);
iph->frag_off = htons(offset >> 3);
if (skb->next)
iph->frag_off |= htons(IP_MF);
offset += skb->len - nhoff - ihl;
} else {
} else if (!fixedid) {
iph->id = htons(id++);
}
iph->tot_len = htons(skb->len - nhoff);

View File

@@ -32,6 +32,7 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
SKB_GSO_UDP |
SKB_GSO_DODGY |
SKB_GSO_TCP_ECN |
SKB_GSO_TCP_FIXEDID |
SKB_GSO_GRE |
SKB_GSO_GRE_CSUM |
SKB_GSO_IPIP |

View File

@@ -89,6 +89,7 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
~(SKB_GSO_TCPV4 |
SKB_GSO_DODGY |
SKB_GSO_TCP_ECN |
SKB_GSO_TCP_FIXEDID |
SKB_GSO_TCPV6 |
SKB_GSO_GRE |
SKB_GSO_GRE_CSUM |
@@ -98,7 +99,8 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
SKB_GSO_UDP_TUNNEL_CSUM |
SKB_GSO_TUNNEL_REMCSUM |
0) ||
!(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
!(type & (SKB_GSO_TCPV4 |
SKB_GSO_TCPV6))))
goto out;
skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);