Commit c63e4de2 authored by Alex Gartrell's avatar Alex Gartrell Committed by Simon Horman
Browse files

ipvs: Add generic ensure_mtu_is_adequate to handle mixed pools 



The out_rt functions check to see if the mtu is large enough for the packet
and, if not, send icmp messages (TOOBIG or DEST_UNREACH) to the source and
bail out.  We needed the ability to send ICMP from the out_rt_v6 function
and DEST_UNREACH from the out_rt function, so we just pulled it out into a
common function.

Signed-off-by: default avatarAlex Gartrell <agartrell@fb.com>
Acked-by: default avatarJulian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarSimon Horman <horms@verge.net.au>
parent 919aa0b2

net/netfilter/ipvs/ip_vs_xmit.c

+51 −26
Original line number Diff line number Diff line
@@ -213,17 +213,57 @@ static inline void maybe_update_pmtu(int skb_af, struct sk_buff *skb, int mtu) 
		ort->dst.ops->update_pmtu(&ort->dst, sk, NULL, mtu);

}



static inline bool ensure_mtu_is_adequate(int skb_af, int rt_mode,

					  struct ip_vs_iphdr *ipvsh,

					  struct sk_buff *skb, int mtu)

{

#ifdef CONFIG_IP_VS_IPV6

	if (skb_af == AF_INET6) {

		struct net *net = dev_net(skb_dst(skb)->dev);



		if (unlikely(__mtu_check_toobig_v6(skb, mtu))) {

			if (!skb->dev)

				skb->dev = net->loopback_dev;

			/* only send ICMP too big on first fragment */

			if (!ipvsh->fragoffs)

				icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);

			IP_VS_DBG(1, "frag needed for %pI6c\n",

				  &ipv6_hdr(skb)->saddr);

			return false;

		}

	} else

#endif

	{

		struct netns_ipvs *ipvs = net_ipvs(skb_net(skb));



		/* If we're going to tunnel the packet and pmtu discovery

		 * is disabled, we'll just fragment it anyway

		 */

		if ((rt_mode & IP_VS_RT_MODE_TUNNEL) && !sysctl_pmtu_disc(ipvs))

			return true;



		if (unlikely(ip_hdr(skb)->frag_off & htons(IP_DF) &&

			     skb->len > mtu && !skb_is_gso(skb))) {

			icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,

				  htonl(mtu));

			IP_VS_DBG(1, "frag needed for %pI4\n",

				  &ip_hdr(skb)->saddr);

			return false;

		}

	}



	return true;

}



/* Get route to destination or remote server */

static int

__ip_vs_get_out_rt(int skb_af, struct sk_buff *skb, struct ip_vs_dest *dest,

		   __be32 daddr, int rt_mode, __be32 *ret_saddr)

		   __be32 daddr, int rt_mode, __be32 *ret_saddr,

		   struct ip_vs_iphdr *ipvsh)

{

	struct net *net = dev_net(skb_dst(skb)->dev);

	struct netns_ipvs *ipvs = net_ipvs(net);

	struct ip_vs_dest_dst *dest_dst;

	struct rtable *rt;			/* Route to the other host */

	struct iphdr *iph;

	__be16 df;

	int mtu;

	int local, noref = 1;
@@ -279,7 +319,6 @@ __ip_vs_get_out_rt(int skb_af, struct sk_buff *skb, struct ip_vs_dest *dest, 
			     " daddr=%pI4\n", &dest->addr.ip);

		goto err_put;

	}

	iph = ip_hdr(skb);



	if (unlikely(local)) {

		/* skb to local stack, preserve old route */
@@ -290,7 +329,6 @@ __ip_vs_get_out_rt(int skb_af, struct sk_buff *skb, struct ip_vs_dest *dest, 


	if (likely(!(rt_mode & IP_VS_RT_MODE_TUNNEL))) {

		mtu = dst_mtu(&rt->dst);

		df = iph->frag_off & htons(IP_DF);

	} else {

		mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);

		if (mtu < 68) {
@@ -298,16 +336,10 @@ __ip_vs_get_out_rt(int skb_af, struct sk_buff *skb, struct ip_vs_dest *dest, 
			goto err_put;

		}

		maybe_update_pmtu(skb_af, skb, mtu);

		/* MTU check allowed? */

		df = sysctl_pmtu_disc(ipvs) ? iph->frag_off & htons(IP_DF) : 0;

	}



	/* MTU checking */

	if (unlikely(df && skb->len > mtu && !skb_is_gso(skb))) {

		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));

		IP_VS_DBG(1, "frag needed for %pI4\n", &iph->saddr);

	if (!ensure_mtu_is_adequate(skb_af, rt_mode, ipvsh, skb, mtu))

		goto err_put;

	}



	skb_dst_drop(skb);

	if (noref) {
@@ -450,15 +482,8 @@ __ip_vs_get_out_rt_v6(int skb_af, struct sk_buff *skb, struct ip_vs_dest *dest, 
		maybe_update_pmtu(skb_af, skb, mtu);

	}



	if (unlikely(__mtu_check_toobig_v6(skb, mtu))) {

		if (!skb->dev)

			skb->dev = net->loopback_dev;

		/* only send ICMP too big on first fragment */

		if (!ipvsh->fragoffs)

			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);

		IP_VS_DBG(1, "frag needed for %pI6c\n", &ipv6_hdr(skb)->saddr);

	if (!ensure_mtu_is_adequate(skb_af, rt_mode, ipvsh, skb, mtu))

		goto err_put;

	}



	skb_dst_drop(skb);

	if (noref) {
@@ -565,7 +590,7 @@ ip_vs_bypass_xmit(struct sk_buff *skb, struct ip_vs_conn *cp, 


	rcu_read_lock();

	if (__ip_vs_get_out_rt(cp->af, skb, NULL, iph->daddr,

			       IP_VS_RT_MODE_NON_LOCAL, NULL) < 0)

			       IP_VS_RT_MODE_NON_LOCAL, NULL, ipvsh) < 0)

		goto tx_error;



	ip_send_check(iph);
@@ -644,7 +669,7 @@ ip_vs_nat_xmit(struct sk_buff *skb, struct ip_vs_conn *cp, 
	local = __ip_vs_get_out_rt(cp->af, skb, cp->dest, cp->daddr.ip,

				   IP_VS_RT_MODE_LOCAL |

				   IP_VS_RT_MODE_NON_LOCAL |

				   IP_VS_RT_MODE_RDR, NULL);

				   IP_VS_RT_MODE_RDR, NULL, ipvsh);

	if (local < 0)

		goto tx_error;

	rt = skb_rtable(skb);
@@ -841,7 +866,7 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp, 
				   IP_VS_RT_MODE_LOCAL |

				   IP_VS_RT_MODE_NON_LOCAL |

				   IP_VS_RT_MODE_CONNECT |

				   IP_VS_RT_MODE_TUNNEL, &saddr);

				   IP_VS_RT_MODE_TUNNEL, &saddr, ipvsh);

	if (local < 0)

		goto tx_error;

	if (local) {
@@ -1032,7 +1057,7 @@ ip_vs_dr_xmit(struct sk_buff *skb, struct ip_vs_conn *cp, 
	local = __ip_vs_get_out_rt(cp->af, skb, cp->dest, cp->daddr.ip,

				   IP_VS_RT_MODE_LOCAL |

				   IP_VS_RT_MODE_NON_LOCAL |

				   IP_VS_RT_MODE_KNOWN_NH, NULL);

				   IP_VS_RT_MODE_KNOWN_NH, NULL, ipvsh);

	if (local < 0)

		goto tx_error;

	if (local) {
@@ -1137,7 +1162,7 @@ ip_vs_icmp_xmit(struct sk_buff *skb, struct ip_vs_conn *cp, 
		  IP_VS_RT_MODE_RDR : IP_VS_RT_MODE_NON_LOCAL;

	rcu_read_lock();

	local = __ip_vs_get_out_rt(cp->af, skb, cp->dest, cp->daddr.ip, rt_mode,

				   NULL);

				   NULL, iph);

	if (local < 0)

		goto tx_error;

	rt = skb_rtable(skb);

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