Fix ICMP error encapsulation to hosts behind B4s

snabbco · Aug 5, 2016 · cb79190 · cb79190
1 parent f64f07e
commit cb79190
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Showing 3 changed files with 21 additions and 14 deletions.
diff --git a/src/apps/lwaftr/lwaftr.lua b/src/apps/lwaftr/lwaftr.lua
@@ -387,14 +387,23 @@ local function transmit_ipv4(lwstate, pkt)
    end
 end
 
+-- Only locally generated error packets are handled here.  We transmit
+-- them right away, instead of calling transmit_ipv4, because they are
+-- never hairpinned and should not be counted by the "out-ipv4" counter.
+-- However, they should be tunneled if the error is to be sent to a host
+-- behind a B4, whether or not hairpinning is enabled; this is not hairpinning.
 local function transmit_icmpv4_reply(lwstate, pkt, orig_pkt)
    drop(orig_pkt)
    counter.add(lwstate.counters["out-icmpv4-bytes"], pkt.length)
    counter.add(lwstate.counters["out-icmpv4-packets"])
-   -- Only locally generated error packets are handled here.  We transmit
-   -- them right away, instead of calling transmit_ipv4, because they are
-   -- never hairpinned and should not be counted by the "out-ipv4" counter.
-   return transmit(lwstate.o4, pkt)
+
+   local ipv4_header = get_ethernet_payload(pkt)
+   local dst_ip = get_ipv4_dst_address(ipv4_header)
+   if ipv4_in_binding_table(lwstate, dst_ip) then
+      return transmit(lwstate.input.v4, pkt)
+   else
+      return transmit(lwstate.o4, pkt)
+   end
 end
 
 -- ICMPv4 type 3 code 1, as per RFC 7596.

diff --git a/src/program/lwaftr/tests/end-to-end/end-to-end-vlan.sh b/src/program/lwaftr/tests/end-to-end/end-to-end-vlan.sh
@@ -253,11 +253,10 @@ snabb_run_and_cmp ${TEST_CONF}/tunnel_icmp_vlan.conf \
    ${EMPTY} ${TEST_DATA}/hairpinned-icmpv4-echo-reply-unbound-from-aftr.pcap \
    ${COUNTERS}/in-1p-ipv6-out-1p-icmpv6-2.lua
 
-# FIXME: fix and reenable this test.
-# echo "Testing: from-to-b4 TCP packet, with hairpinning, TTL 1"
-# snabb_run_and_cmp ${TEST_CONF}/tunnel_icmp_vlan.conf \
-#    ${EMPTY} ${TEST_DATA}/tcp-fromb4-tob4-ipv6-ttl-1.pcap \
-#    ${EMPTY} ${TEST_DATA}/tcp-fromb4-tob4-ipv6-ttl-1-reply.pcap
+echo "Testing: from-to-b4 TCP packet, with hairpinning, TTL 1"
+snabb_run_and_cmp ${TEST_CONF}/tunnel_icmp_vlan.conf \
+   ${EMPTY} ${TEST_DATA}/tcp-fromb4-tob4-ipv6-ttl-1.pcap \
+   ${EMPTY} ${TEST_DATA}/tcp-fromb4-tob4-ipv6-ttl-1-reply.pcap
 
 echo "Testing: from-b4 IPv6 packet, with hairpinning, to B4 with custom lwAFTR address"
 snabb_run_and_cmp ${TEST_CONF}/no_icmp_vlan.conf \

diff --git a/src/program/lwaftr/tests/end-to-end/end-to-end.sh b/src/program/lwaftr/tests/end-to-end/end-to-end.sh
@@ -270,11 +270,10 @@ snabb_run_and_cmp ${TEST_BASE}/tunnel_icmp.conf \
    ${EMPTY} ${TEST_BASE}/hairpinned-icmpv4-echo-reply-unbound-from-aftr.pcap \
    ${COUNTERS}/in-1p-ipv6-out-1p-icmpv6-2.lua
 
-# FIXME: fix and reenable this test.
-# echo "Testing: from-to-b4 TCP packet, with hairpinning, TTL 1"
-# snabb_run_and_cmp ${TEST_BASE}/tunnel_icmp.conf \
-#    ${EMPTY} ${TEST_BASE}/tcp-fromb4-tob4-ipv6-ttl-1.pcap \
-#    ${EMPTY} ${TEST_BASE}/tcp-fromb4-tob4-ipv6-ttl-1-reply.pcap
+echo "Testing: from-to-b4 TCP packet, with hairpinning, TTL 1"
+snabb_run_and_cmp ${TEST_BASE}/tunnel_icmp.conf \
+   ${EMPTY} ${TEST_BASE}/tcp-fromb4-tob4-ipv6-ttl-1.pcap \
+   ${EMPTY} ${TEST_BASE}/tcp-fromb4-tob4-ipv6-ttl-1-reply.pcap
 
 echo "Testing: from-to-b4 IPv6 packet, with hairpinning, with vlan tag"
 snabb_run_and_cmp ${TEST_BASE}/vlan.conf \