[ovs-dev] [PATCH 2/2] OVN: add tcp_reset action to ovn acl reject support
Lorenzo Bianconi
lorenzo.bianconi at redhat.com
Wed Apr 4 15:06:37 UTC 2018
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 at redhat.com>
---
ovn/northd/ovn-northd.c | 30 ++++++++++++++++++++++++------
ovn/ovn-nb.xml | 1 -
tests/ovn.at | 32 ++++++++++++++++++++++++++++++++
3 files changed, 56 insertions(+), 7 deletions(-)
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
--
2.14.3
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