NAT64: Hairpinning (VPP-699)
Change-Id: I83a6c277fa211ac2c2ca2d603650c992886af0a7
Signed-off-by: Matus Fabian <matfabia@cisco.com>
diff --git a/src/vnet/ip/ip4_to_ip6.h b/src/vnet/ip/ip4_to_ip6.h
index dad3523..cdd3707 100644
--- a/src/vnet/ip/ip4_to_ip6.h
+++ b/src/vnet/ip/ip4_to_ip6.h
@@ -321,17 +321,9 @@
//We have an ICMP inside an ICMP
//It needs to be translated, but not for error ICMP messages
icmp46_header_t *inner_icmp = (icmp46_header_t *) (inner_ip4 + 1);
- csum = inner_icmp->checksum;
//Only types ICMP4_echo_request and ICMP4_echo_reply are handled by icmp_to_icmp6_header
- csum = ip_csum_sub_even (csum, *((u16 *) inner_icmp));
inner_icmp->type = (inner_icmp->type == ICMP4_echo_request) ?
ICMP6_echo_request : ICMP6_echo_reply;
- csum = ip_csum_add_even (csum, *((u16 *) inner_icmp));
- csum =
- ip_csum_add_even (csum, clib_host_to_net_u16 (IP_PROTOCOL_ICMP6));
- csum =
- ip_csum_add_even (csum, inner_ip4->length - sizeof (*inner_ip4));
- inner_icmp->checksum = ip_csum_fold (csum);
inner_L4_checksum = &inner_icmp->checksum;
inner_ip4->protocol = IP_PROTOCOL_ICMP6;
}
@@ -341,8 +333,6 @@
os_panic ();
}
- csum = *inner_L4_checksum; //Initial checksum of the inner L4 header
-
inner_ip6->ip_version_traffic_class_and_flow_label =
clib_host_to_net_u32 ((6 << 28) + (inner_ip4->tos << 20));
inner_ip6->payload_length =
@@ -367,14 +357,42 @@
sizeof (*inner_frag));
}
- /* UDP checksum is optional */
- if (csum)
+ csum = *inner_L4_checksum;
+ if (inner_ip6->protocol == IP_PROTOCOL_ICMP6)
{
- csum = ip_csum_add_even (csum, inner_ip6->src_address.as_u64[0]);
- csum = ip_csum_add_even (csum, inner_ip6->src_address.as_u64[1]);
- csum = ip_csum_add_even (csum, inner_ip6->dst_address.as_u64[0]);
- csum = ip_csum_add_even (csum, inner_ip6->dst_address.as_u64[1]);
- *inner_L4_checksum = ip_csum_fold (csum);
+ //Recompute ICMP checksum
+ icmp46_header_t *inner_icmp = (icmp46_header_t *) (inner_ip4 + 1);
+
+ inner_icmp->checksum = 0;
+ csum = ip_csum_with_carry (0, inner_ip6->payload_length);
+ csum =
+ ip_csum_with_carry (csum,
+ clib_host_to_net_u16 (inner_ip6->protocol));
+ csum = ip_csum_with_carry (csum, inner_ip6->src_address.as_u64[0]);
+ csum = ip_csum_with_carry (csum, inner_ip6->src_address.as_u64[1]);
+ csum = ip_csum_with_carry (csum, inner_ip6->dst_address.as_u64[0]);
+ csum = ip_csum_with_carry (csum, inner_ip6->dst_address.as_u64[1]);
+ csum =
+ ip_incremental_checksum (csum, inner_icmp,
+ clib_net_to_host_u16
+ (inner_ip6->payload_length));
+ inner_icmp->checksum = ~ip_csum_fold (csum);
+ }
+ else
+ {
+ /* UDP checksum is optional */
+ if (csum)
+ {
+ csum =
+ ip_csum_add_even (csum, inner_ip6->src_address.as_u64[0]);
+ csum =
+ ip_csum_add_even (csum, inner_ip6->src_address.as_u64[1]);
+ csum =
+ ip_csum_add_even (csum, inner_ip6->dst_address.as_u64[0]);
+ csum =
+ ip_csum_add_even (csum, inner_ip6->dst_address.as_u64[1]);
+ *inner_L4_checksum = ip_csum_fold (csum);
+ }
}
}
else
@@ -518,6 +536,7 @@
csum = ip_csum_sub_even (*checksum, ip4->src_address.as_u32);
csum = ip_csum_sub_even (csum, ip4->dst_address.as_u32);
+ *checksum = ip_csum_fold (csum);
// Deal with fragmented packets
if (PREDICT_FALSE (ip4->flags_and_fragment_offset &
@@ -558,7 +577,7 @@
if ((rv = fn (ip4, ip6, ctx)) != 0)
return rv;
- csum = ip_csum_add_even (csum, ip6->src_address.as_u64[0]);
+ csum = ip_csum_add_even (*checksum, ip6->src_address.as_u64[0]);
csum = ip_csum_add_even (csum, ip6->src_address.as_u64[1]);
csum = ip_csum_add_even (csum, ip6->dst_address.as_u64[0]);
csum = ip_csum_add_even (csum, ip6->dst_address.as_u64[1]);