Recognize UDP tunnels in received ICMP errors and
properly strip the tunnel headers. GUE is what we
have for now.
Signed-off-by: Julian Anastasov <ja@xxxxxx>
---
net/netfilter/ipvs/ip_vs_core.c | 58 +++++++++++++++++++++++++++++++++
1 file changed, 58 insertions(+)
diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
index 4447ee512b88..0b624e8e7982 100644
--- a/net/netfilter/ipvs/ip_vs_core.c
+++ b/net/netfilter/ipvs/ip_vs_core.c
@@ -39,6 +39,7 @@
#include <net/tcp.h>
#include <net/udp.h>
#include <net/icmp.h> /* for icmp_send */
+#include <net/gue.h>
#include <net/route.h>
#include <net/ip6_checksum.h>
#include <net/netns/generic.h> /* net_generic() */
@@ -1579,6 +1580,34 @@ ip_vs_try_to_schedule(struct netns_ipvs *ipvs, int af, struct sk_buff *skb,
return 1;
}
+/* Check the UDP tunnel and return its header length */
+static int ipvs_udp_decap(struct netns_ipvs *ipvs, struct sk_buff *skb,
+ unsigned int offset, __u16 af, __be16 dport,
+ const union nf_inet_addr *daddr, __u8 *proto)
+{
+ struct ip_vs_dest *dest = ip_vs_find_tunnel(ipvs, af, daddr, dport);
+
+ if (!dest)
+ goto unk;
+ if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
+ struct guehdr _gueh, *gueh;
+
+ gueh = skb_header_pointer(skb, offset, sizeof(_gueh), &_gueh);
+ if (!gueh)
+ goto unk;
+ if (gueh->control != 0 || gueh->version != 0)
+ goto unk;
+ /* Later we can support also IPPROTO_IPV6 */
+ if (gueh->proto_ctype != IPPROTO_IPIP)
+ goto unk;
+ *proto = gueh->proto_ctype;
+ return sizeof(struct guehdr) + (gueh->hlen << 2);
+ }
+
+unk:
+ return -1;
+}
+
/*
* Handle ICMP messages in the outside-to-inside direction (incoming).
* Find any that might be relevant, check against existing connections,
@@ -1658,8 +1687,37 @@ ip_vs_in_icmp(struct netns_ipvs *ipvs, struct sk_buff *skb, int *related,
if (cih == NULL)
return NF_ACCEPT; /* The packet looks wrong, ignore */
ipip = true;
+ } else if (cih->protocol == IPPROTO_UDP) { /* Can be UDP encap */
+ struct udphdr _udph, *udph;
+ __u8 iproto;
+ int ulen;
+
+ if (unlikely(cih->frag_off & htons(IP_OFFSET)))
+ return NF_ACCEPT;
+ /* Error for our tunnel must arrive at LOCAL_IN */
+ if (!(skb_rtable(skb)->rt_flags & RTCF_LOCAL))
+ return NF_ACCEPT;
+ offset2 = offset + cih->ihl * 4;
+ udph = skb_header_pointer(skb, offset2, sizeof(_udph), &_udph);
+ if (!udph)
+ goto check;
+ offset2 += sizeof(struct udphdr);
+ ulen = ipvs_udp_decap(ipvs, skb, offset2, AF_INET, udph->dest,
+ raddr, &iproto);
+ if (ulen < 0)
+ goto check;
+ /* Skip IP + UDP + ulen */
+ offset = offset2 + ulen;
+ /* Now we should be at the original IP header */
+ cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
+ if (cih && cih->version == 4 && cih->ihl >= 5 &&
+ iproto == IPPROTO_IPIP)
+ ipip = true;
+ else
+ return NF_ACCEPT;
}
+check:
pd = ip_vs_proto_data_get(ipvs, cih->protocol);
if (!pd)
return NF_ACCEPT;
--
2.17.1
