[ovs-dev,2/2] OVN: add tcp_reset action to ovn acl reject support
diff mbox series

Message ID 13396a4c549d425aada79fc19307f93e58249271.1522853801.git.lorenzo.bianconi@redhat.com
State Accepted
Headers show
Series
  • add tcp reset support to ovn acl framework
Related show

Commit Message

Lorenzo Bianconi April 4, 2018, 3:06 p.m. UTC
Whenever the acl reject rule is hit by a TCP segment send back
a TCP RST packet to close the connection using the tcp_reset action.
Moreover add add tcp_reset test case to 'ACL reject rule test'

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
---
 ovn/northd/ovn-northd.c | 30 ++++++++++++++++++++++++------
 ovn/ovn-nb.xml          |  1 -
 tests/ovn.at            | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 56 insertions(+), 7 deletions(-)

Patch
diff mbox series

diff --git a/ovn/northd/ovn-northd.c b/ovn/northd/ovn-northd.c
index 396381049..07896be84 100644
--- a/ovn/northd/ovn-northd.c
+++ b/ovn/northd/ovn-northd.c
@@ -2905,9 +2905,11 @@  build_pre_acls(struct ovn_datapath *od, struct hmap *lflows)
          * Not to do conntrack on ND and ICMP destination
          * unreachable packets. */
         ovn_lflow_add(lflows, od, S_SWITCH_IN_PRE_ACL, 110,
-                      "nd || nd_rs || nd_ra || icmp4.type == 3", "next;");
+                      "nd || nd_rs || nd_ra || icmp4.type == 3 || "
+                      "(tcp && tcp.flags == 4)", "next;");
         ovn_lflow_add(lflows, od, S_SWITCH_OUT_PRE_ACL, 110,
-                      "nd || nd_rs || nd_ra || icmp4.type == 3", "next;");
+                      "nd || nd_rs || nd_ra || icmp4.type == 3 || "
+                      "(tcp && tcp.flags == 4)", "next;");
 
         /* Ingress and Egress Pre-ACL Table (Priority 100).
          *
@@ -3097,14 +3099,30 @@  build_reject_acl_rules(struct ovn_datapath *od, struct hmap *lflows,
     struct ds actions = DS_EMPTY_INITIALIZER;
     bool ingress = (stage == S_SWITCH_IN_ACL);
 
-    /* XXX: Treat TCP connections as "drop;" for now */
+    /* TCP */
     build_acl_log(&actions, acl);
     if (extra_match->length > 0) {
         ds_put_format(&match, "(%s) && ", extra_match->string);
     }
-    ds_put_format(&match, "ip && tcp && (%s)", acl->match);
-    ds_put_cstr(&actions, "/* drop */");
-    ovn_lflow_add(lflows, od, stage, acl->priority + OVN_ACL_PRI_OFFSET,
+    ds_put_format(&match, "ip4 && tcp && (%s)", acl->match);
+    ds_put_format(&actions, "reg0 = 0; "
+                  "eth.dst <-> eth.src; ip4.dst <-> ip4.src; "
+                  "tcp_reset { outport <-> inport; %s };",
+                  ingress ? "output;" : "next(pipeline=ingress,table=0);");
+    ovn_lflow_add(lflows, od, stage, acl->priority + OVN_ACL_PRI_OFFSET + 10,
+                  ds_cstr(&match), ds_cstr(&actions));
+    ds_clear(&match);
+    ds_clear(&actions);
+    build_acl_log(&actions, acl);
+    if (extra_match->length > 0) {
+        ds_put_format(&match, "(%s) && ", extra_match->string);
+    }
+    ds_put_format(&match, "ip6 && tcp && (%s)", acl->match);
+    ds_put_format(&actions, "reg0 = 0; "
+                  "eth.dst <-> eth.src; ip6.dst <-> ip6.src; "
+                  "tcp_reset { outport <-> inport; %s };",
+                  ingress ? "output;" : "next(pipeline=ingress,table=0);");
+    ovn_lflow_add(lflows, od, stage, acl->priority + OVN_ACL_PRI_OFFSET + 10,
                   ds_cstr(&match), ds_cstr(&actions));
 
     /* IPv4 traffic */
diff --git a/ovn/ovn-nb.xml b/ovn/ovn-nb.xml
index 6bb93dedd..2ebaac561 100644
--- a/ovn/ovn-nb.xml
+++ b/ovn/ovn-nb.xml
@@ -1062,7 +1062,6 @@ 
         <li>
           <code>reject</code>: Drop the packet, replying with a RST for TCP or
           ICMP unreachable message for other IP-based protocols.
-          <code>Not implemented--currently treated as drop</code>
         </li>
       </ul>
     </column>
diff --git a/tests/ovn.at b/tests/ovn.at
index 4cd3bbf9b..0f37b8892 100644
--- a/tests/ovn.at
+++ b/tests/ovn.at
@@ -9386,6 +9386,34 @@  test_ip_packet() {
     as hv$hv ovs-appctl netdev-dummy/receive vif$inport $packet
 }
 
+# test_tcp_syn_packet INPORT HV ETH_SRC ETH_DST IPV4_SRC IPV4_DST IP_CHKSUM TCP_SPORT TCP_DPORT TCP_CHKSUM EXP_IP_CHKSUM EXP_TCP_RST_CHKSUM
+#
+# Causes a packet to be received on INPORT of the hypervisor HV. The packet is an TCP syn segment with
+# ETH_SRC, ETH_DST, IPV4_SRC, IPV4_DST, IP_CHKSUM, TCP_SPORT, TCP_DPORT, TCP_CHKSUM  as specified.
+# EXP_IP_CHKSUM and EXP_TCP_RST_CHKSUM are the ip and tcp checksums of the tcp reset segment generated from ACL rule hit
+#
+# INPORT is an lport number, e.g. 11 for vif11.
+# HV is an hypervisor number
+# ETH_SRC and ETH_DST are each 12 hex digits.
+# IPV4_SRC and IPV4_DST are each 8 hex digits.
+# TCP_SPORT and TCP_DPORT are 4 hex digits.
+# IP_CHKSUM, TCP_CHKSUM, EXP_IP_CHSUM and EXP_TCP_RST_CHKSUM are each 4 hex digits
+test_tcp_syn_packet() {
+    local inport=$1 hv=$2 eth_src=$3 eth_dst=$4 ipv4_src=$5 ipv4_dst=$6 ip_chksum=$7
+    local tcp_sport=$8 tcp_dport=$9 tcp_chksum=${10}
+    local exp_ip_chksum=${11} exp_tcp_rst_chksum=${12}
+    shift 12
+
+    local ip_ttl=ff
+    local packet=${eth_dst}${eth_src}08004500002800004000${ip_ttl}06${ip_chksum}${ipv4_src}${ipv4_dst}${tcp_sport}${tcp_dport}000000010000000050027210${tcp_chksum}0000
+
+    local tcp_rst_ttl=ff
+    local reply=${eth_src}${eth_dst}08004500002800004000${tcp_rst_ttl}06${exp_ip_chksum}${ipv4_dst}${ipv4_src}${tcp_dport}${tcp_sport}000000000000000150040000${exp_tcp_rst_chksum}0000
+    echo $reply >> vif$inport.expected
+
+    as hv$hv ovs-appctl netdev-dummy/receive vif$inport $packet
+}
+
 # Create hypervisors hv[123].
 # Add vif1[123] to hv1, vif2[123] to hv2, vif3[123] to hv3.
 # Add all of the vifs to a single logical switch sw0.
@@ -9432,6 +9460,10 @@  test_ip_packet 11 1 000000000011 000000000021 $(ip_to_hex 192 168 1 11) $(ip_to_
 test_ip_packet 21 2 000000000021 000000000011 $(ip_to_hex 192 168 1 21) $(ip_to_hex 192 168 1 11) 0000 7d8d fcfe
 test_ip_packet 31 3 000000000031 000000000012 $(ip_to_hex 192 168 1 31) $(ip_to_hex 192 168 1 12) 0000 7d82 fcfe
 
+test_tcp_syn_packet 11 1 000000000011 000000000021 $(ip_to_hex 192 168 1 11) $(ip_to_hex 192 168 1 21) 0000 8b40 3039 0000 7d8d 4486
+test_tcp_syn_packet 21 2 000000000021 000000000011 $(ip_to_hex 192 168 1 21) $(ip_to_hex 192 168 1 11) 0000 8b40 3039 0000 7d8d 4486
+test_tcp_syn_packet 31 3 000000000031 000000000012 $(ip_to_hex 192 168 1 31) $(ip_to_hex 192 168 1 12) 0000 8b40 3039 0000 7d82 4486
+
 for i in 1 2 3; do
     OVN_CHECK_PACKETS([hv$i/vif${i}1-tx.pcap], [vif${i}1.expected])
 done