On Tue, Nov 09, 2010 at 10:08:49AM +0900, Simon Horman wrote:
> Attempt at allowing LVS to transmit skbs of greater than MTU length that
> have been aggregated by GRO and can thus be deaggregated by GSO.
>
> Cc: Julian Anastasov <ja@xxxxxx>
> Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>
>
> ---
>
> * LRO is still an outstanding issue, but as its deprecated in favour
> of GRO perhaps it doesn't need to be solved.
>
> * v1
> - Based on 2.6.35
>
> * v2
> - Rebase on current nf-next-2.6 tree (~2.6.37-rc1)
>
> * v3
> - Use skb_is_gso() instead of netif_needs_gso() as suggested by
> Julian Anastasov and confirmed by Herbert Xu.
On thinking about this a bit more, I believe that this is material
for stable as its affecting deployed systems. I'll back-port it
and add the appropriate CC once its seen a bit more testing.
>
> Index: lvs-test-2.6/net/netfilter/ipvs/ip_vs_xmit.c
> ===================================================================
> --- lvs-test-2.6.orig/net/netfilter/ipvs/ip_vs_xmit.c 2010-11-08 16:27:31.000000000 +0900
> +++ lvs-test-2.6/net/netfilter/ipvs/ip_vs_xmit.c 2010-11-08 16:29:19.000000000 +0900
> @@ -408,7 +408,8 @@ ip_vs_bypass_xmit(struct sk_buff *skb, s
>
> /* MTU checking */
> mtu = dst_mtu(&rt->dst);
> - if ((skb->len > mtu) && (iph->frag_off & htons(IP_DF))) {
> + if ((skb->len > mtu) && (iph->frag_off & htons(IP_DF)) &&
> + !skb_is_gso(skb)) {
> ip_rt_put(rt);
> icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
> IP_VS_DBG_RL("%s(): frag needed\n", __func__);
> @@ -461,7 +462,7 @@ ip_vs_bypass_xmit_v6(struct sk_buff *skb
>
> /* MTU checking */
> mtu = dst_mtu(&rt->dst);
> - if (skb->len > mtu) {
> + if (skb->len > mtu && !skb_is_gso(skb)) {
> if (!skb->dev) {
> struct net *net = dev_net(skb_dst(skb)->dev);
>
> @@ -560,7 +561,8 @@ ip_vs_nat_xmit(struct sk_buff *skb, stru
>
> /* MTU checking */
> mtu = dst_mtu(&rt->dst);
> - if ((skb->len > mtu) && (iph->frag_off & htons(IP_DF))) {
> + if ((skb->len > mtu) && (iph->frag_off & htons(IP_DF)) &&
> + !skb_is_gso(skb)) {
> icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
> IP_VS_DBG_RL_PKT(0, AF_INET, pp, skb, 0,
> "ip_vs_nat_xmit(): frag needed for");
> @@ -675,7 +677,7 @@ ip_vs_nat_xmit_v6(struct sk_buff *skb, s
>
> /* MTU checking */
> mtu = dst_mtu(&rt->dst);
> - if (skb->len > mtu) {
> + if (skb->len > mtu && !skb_is_gso(skb)) {
> if (!skb->dev) {
> struct net *net = dev_net(skb_dst(skb)->dev);
>
> @@ -790,8 +792,8 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, s
>
> df |= (old_iph->frag_off & htons(IP_DF));
>
> - if ((old_iph->frag_off & htons(IP_DF))
> - && mtu < ntohs(old_iph->tot_len)) {
> + if ((old_iph->frag_off & htons(IP_DF) &&
> + mtu < ntohs(old_iph->tot_len) && !skb_is_gso(skb))) {
> icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
> IP_VS_DBG_RL("%s(): frag needed\n", __func__);
> goto tx_error_put;
> @@ -903,7 +905,8 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb
> if (skb_dst(skb))
> skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
>
> - if (mtu < ntohs(old_iph->payload_len) + sizeof(struct ipv6hdr)) {
> + if (mtu < ntohs(old_iph->payload_len) + sizeof(struct ipv6hdr) &&
> + !skb_is_gso(skb)) {
> if (!skb->dev) {
> struct net *net = dev_net(skb_dst(skb)->dev);
>
> @@ -1008,7 +1011,8 @@ ip_vs_dr_xmit(struct sk_buff *skb, struc
>
> /* MTU checking */
> mtu = dst_mtu(&rt->dst);
> - if ((iph->frag_off & htons(IP_DF)) && skb->len > mtu) {
> + if ((iph->frag_off & htons(IP_DF)) && skb->len > mtu &&
> + !skb_is_gso(skb)) {
> icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
> ip_rt_put(rt);
> IP_VS_DBG_RL("%s(): frag needed\n", __func__);
> @@ -1174,7 +1178,8 @@ ip_vs_icmp_xmit(struct sk_buff *skb, str
>
> /* MTU checking */
> mtu = dst_mtu(&rt->dst);
> - if ((skb->len > mtu) && (ip_hdr(skb)->frag_off & htons(IP_DF))) {
> + if ((skb->len > mtu) && (ip_hdr(skb)->frag_off & htons(IP_DF)) &&
> + !skb_is_gso(skb)) {
> icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
> IP_VS_DBG_RL("%s(): frag needed\n", __func__);
> goto tx_error_put;
> @@ -1288,7 +1293,7 @@ ip_vs_icmp_xmit_v6(struct sk_buff *skb,
>
> /* MTU checking */
> mtu = dst_mtu(&rt->dst);
> - if (skb->len > mtu) {
> + if (skb->len > mtu && !skb_is_gso(skb)) {
> if (!skb->dev) {
> struct net *net = dev_net(skb_dst(skb)->dev);
>
> --
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