From 3654e61137db891f5312e6dd813b961484b5fdf3 Mon Sep 17 00:00:00 2001 From: Julian Anastasov Date: Fri, 20 Jul 2012 11:59:53 +0300 Subject: [PATCH] ipvs: add pmtu_disc option to disable IP DF for TUN packets Disabling PMTU discovery can increase the output packet rate but some users have enough resources and prefer to fragment than to drop traffic. By default, we copy the DF bit but if pmtu_disc is disabled we do not send FRAG_NEEDED messages anymore. Signed-off-by: Julian Anastasov Signed-off-by: Simon Horman --- include/net/ip_vs.h | 11 +++++++++++ net/netfilter/ipvs/ip_vs_ctl.c | 8 ++++++++ net/netfilter/ipvs/ip_vs_xmit.c | 6 +++--- 3 files changed, 22 insertions(+), 3 deletions(-) diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h index 4b8f18ff4789..ee75ccdf5188 100644 --- a/include/net/ip_vs.h +++ b/include/net/ip_vs.h @@ -888,6 +888,7 @@ struct netns_ipvs { unsigned int sysctl_sync_refresh_period; int sysctl_sync_retries; int sysctl_nat_icmp_send; + int sysctl_pmtu_disc; /* ip_vs_lblc */ int sysctl_lblc_expiration; @@ -974,6 +975,11 @@ static inline int sysctl_sync_sock_size(struct netns_ipvs *ipvs) return ipvs->sysctl_sync_sock_size; } +static inline int sysctl_pmtu_disc(struct netns_ipvs *ipvs) +{ + return ipvs->sysctl_pmtu_disc; +} + #else static inline int sysctl_sync_threshold(struct netns_ipvs *ipvs) @@ -1016,6 +1022,11 @@ static inline int sysctl_sync_sock_size(struct netns_ipvs *ipvs) return 0; } +static inline int sysctl_pmtu_disc(struct netns_ipvs *ipvs) +{ + return 1; +} + #endif /* diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c index d6d5ccabe067..03d3fc6d9d64 100644 --- a/net/netfilter/ipvs/ip_vs_ctl.c +++ b/net/netfilter/ipvs/ip_vs_ctl.c @@ -1801,6 +1801,12 @@ static struct ctl_table vs_vars[] = { .mode = 0644, .proc_handler = proc_dointvec, }, + { + .procname = "pmtu_disc", + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, #ifdef CONFIG_IP_VS_DEBUG { .procname = "debug_level", @@ -3726,6 +3732,8 @@ static int __net_init ip_vs_control_net_init_sysctl(struct net *net) ipvs->sysctl_sync_retries = clamp_t(int, DEFAULT_SYNC_RETRIES, 0, 3); tbl[idx++].data = &ipvs->sysctl_sync_retries; tbl[idx++].data = &ipvs->sysctl_nat_icmp_send; + ipvs->sysctl_pmtu_disc = 1; + tbl[idx++].data = &ipvs->sysctl_pmtu_disc; ipvs->sysctl_hdr = register_net_sysctl(net, "net/ipv4/vs", tbl); diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c index c2275ba048e9..543a554008af 100644 --- a/net/netfilter/ipvs/ip_vs_xmit.c +++ b/net/netfilter/ipvs/ip_vs_xmit.c @@ -795,6 +795,7 @@ int ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp, struct ip_vs_protocol *pp) { + struct netns_ipvs *ipvs = net_ipvs(skb_net(skb)); struct rtable *rt; /* Route to the other host */ __be32 saddr; /* Source for tunnel */ struct net_device *tdev; /* Device to other host */ @@ -830,10 +831,9 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp, skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu); /* Copy DF, reset fragment offset and MF */ - df = old_iph->frag_off & htons(IP_DF); + df = sysctl_pmtu_disc(ipvs) ? old_iph->frag_off & htons(IP_DF) : 0; - if ((old_iph->frag_off & htons(IP_DF) && - mtu < ntohs(old_iph->tot_len) && !skb_is_gso(skb))) { + if (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; -- 2.20.1