[PATCH] ipvs: optimize tunnel dumps for icmp errors

From: Haishuang Yan
Date: Sun Mar 15 2020 - 02:28:15 EST


After strip GRE/UDP tunnel header for icmp errors, it's better to show
"ICMP for GRE/UDP" instead of "ICMP for IPIP" in debug message.

Signed-off-by: Haishuang Yan <yanhaishuang@xxxxxxxxxxxxxxxxxxxx>
---
net/netfilter/ipvs/ip_vs_core.c | 41 +++++++++++++++++++++++------------------
1 file changed, 23 insertions(+), 18 deletions(-)

diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
index 512259f..f39ae6b 100644
--- a/net/netfilter/ipvs/ip_vs_core.c
+++ b/net/netfilter/ipvs/ip_vs_core.c
@@ -114,6 +114,10 @@ const char *ip_vs_proto_name(unsigned int proto)
return "SCTP";
case IPPROTO_ICMP:
return "ICMP";
+ case IPPROTO_IPIP:
+ return "IPIP";
+ case IPPROTO_GRE:
+ return "GRE";
#ifdef CONFIG_IP_VS_IPV6
case IPPROTO_ICMPV6:
return "ICMPv6";
@@ -1661,7 +1665,7 @@ static int ipvs_gre_decap(struct netns_ipvs *ipvs, struct sk_buff *skb,
struct ip_vs_protocol *pp;
struct ip_vs_proto_data *pd;
unsigned int offset, offset2, ihl, verdict;
- bool ipip, new_cp = false;
+ bool tunnel, new_cp = false;
union nf_inet_addr *raddr;

*related = 1;
@@ -1703,8 +1707,8 @@ static int ipvs_gre_decap(struct netns_ipvs *ipvs, struct sk_buff *skb,
return NF_ACCEPT; /* The packet looks wrong, ignore */
raddr = (union nf_inet_addr *)&cih->daddr;

- /* Special case for errors for IPIP packets */
- ipip = false;
+ /* Special case for errors for IPIP/UDP/GRE tunnel packets */
+ tunnel = false;
if (cih->protocol == IPPROTO_IPIP) {
struct ip_vs_dest *dest;

@@ -1721,7 +1725,7 @@ static int ipvs_gre_decap(struct netns_ipvs *ipvs, struct sk_buff *skb,
cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
if (cih == NULL)
return NF_ACCEPT; /* The packet looks wrong, ignore */
- ipip = true;
+ tunnel = true;
} else if ((cih->protocol == IPPROTO_UDP || /* Can be UDP encap */
cih->protocol == IPPROTO_GRE) && /* Can be GRE encap */
/* Error for our tunnel must arrive at LOCAL_IN */
@@ -1729,7 +1733,7 @@ static int ipvs_gre_decap(struct netns_ipvs *ipvs, struct sk_buff *skb,
__u8 iproto;
int ulen;

- /* Non-first fragment has no UDP header */
+ /* Non-first fragment has no UDP/GRE header */
if (unlikely(cih->frag_off & htons(IP_OFFSET)))
return NF_ACCEPT;
offset2 = offset + cih->ihl * 4;
@@ -1747,7 +1751,7 @@ static int ipvs_gre_decap(struct netns_ipvs *ipvs, struct sk_buff *skb,
&_ciph);
if (cih && cih->version == 4 && cih->ihl >= 5 &&
iproto == IPPROTO_IPIP)
- ipip = true;
+ tunnel = true;
else
return NF_ACCEPT;
}
@@ -1767,11 +1771,11 @@ static int ipvs_gre_decap(struct netns_ipvs *ipvs, struct sk_buff *skb,
"Checking incoming ICMP for");

offset2 = offset;
- ip_vs_fill_iph_skb_icmp(AF_INET, skb, offset, !ipip, &ciph);
+ ip_vs_fill_iph_skb_icmp(AF_INET, skb, offset, !tunnel, &ciph);
offset = ciph.len;

/* The embedded headers contain source and dest in reverse order.
- * For IPIP this is error for request, not for reply.
+ * For IPIP/UDP/GRE tunnel this is error for request, not for reply.
*/
cp = INDIRECT_CALL_1(pp->conn_in_get, ip_vs_conn_in_get_proto,
ipvs, AF_INET, skb, &ciph);
@@ -1779,7 +1783,7 @@ static int ipvs_gre_decap(struct netns_ipvs *ipvs, struct sk_buff *skb,
if (!cp) {
int v;

- if (ipip || !sysctl_schedule_icmp(ipvs))
+ if (tunnel || !sysctl_schedule_icmp(ipvs))
return NF_ACCEPT;

if (!ip_vs_try_to_schedule(ipvs, AF_INET, skb, pd, &v, &cp, &ciph))
@@ -1797,7 +1801,7 @@ static int ipvs_gre_decap(struct netns_ipvs *ipvs, struct sk_buff *skb,
goto out;
}

- if (ipip) {
+ if (tunnel) {
__be32 info = ic->un.gateway;
__u8 type = ic->type;
__u8 code = ic->code;
@@ -1809,17 +1813,18 @@ static int ipvs_gre_decap(struct netns_ipvs *ipvs, struct sk_buff *skb,
u32 mtu = ntohs(ic->un.frag.mtu);
__be16 frag_off = cih->frag_off;

- /* Strip outer IP and ICMP, go to IPIP header */
+ /* Strip outer IP and ICMP, go to IPIP/UDP/GRE header */
if (pskb_pull(skb, ihl + sizeof(_icmph)) == NULL)
- goto ignore_ipip;
+ goto ignore_tunnel;
offset2 -= ihl + sizeof(_icmph);
skb_reset_network_header(skb);
- IP_VS_DBG(12, "ICMP for IPIP %pI4->%pI4: mtu=%u\n",
- &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, mtu);
+ IP_VS_DBG(12, "ICMP for %s %pI4->%pI4: mtu=%u\n",
+ ip_vs_proto_name(cih->protocol),
+ &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, mtu);
ipv4_update_pmtu(skb, ipvs->net, mtu, 0, 0);
/* Client uses PMTUD? */
if (!(frag_off & htons(IP_DF)))
- goto ignore_ipip;
+ goto ignore_tunnel;
/* Prefer the resulting PMTU */
if (dest) {
struct ip_vs_dest_dst *dest_dst;
@@ -1832,11 +1837,11 @@ static int ipvs_gre_decap(struct netns_ipvs *ipvs, struct sk_buff *skb,
mtu -= sizeof(struct iphdr);
info = htonl(mtu);
}
- /* Strip outer IP, ICMP and IPIP, go to IP header of
+ /* Strip outer IP, ICMP and IPIP/UDP/GRE, go to IP header of
* original request.
*/
if (pskb_pull(skb, offset2) == NULL)
- goto ignore_ipip;
+ goto ignore_tunnel;
skb_reset_network_header(skb);
IP_VS_DBG(12, "Sending ICMP for %pI4->%pI4: t=%u, c=%u, i=%u\n",
&ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
@@ -1845,7 +1850,7 @@ static int ipvs_gre_decap(struct netns_ipvs *ipvs, struct sk_buff *skb,
/* ICMP can be shorter but anyways, account it */
ip_vs_out_stats(cp, skb);

-ignore_ipip:
+ignore_tunnel:
consume_skb(skb);
verdict = NF_STOLEN;
goto out;
--
1.8.3.1