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ovn-northd: Add flows in DHCP_OPTIONS pipeline to support renew requests
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ovn-northd adds the flows to send the DHCPv4 packets to ovn-controller
only with the match ip4.src = 0.0.0.0 and ip4.dst = 255.255.255.255.

When a DHCPv4 lease is about to expire, before sending a DHCPDISCOVER
packet, the client can send a DHCPREQUEST packet to renew its ip
with ip4.src set to its offered ip and ip4.dst set to the DHCP server
ip or broadcast ip.

This patch supports this missing scenario by adding the necessary
flows in DHCP_OPTIONS ingress pipeline.

Signed-off-by: Numan Siddique <nusiddiq@redhat.com>
Signed-off-by: Russell Bryant <russell@ovn.org>
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@numansiddique @russellb
numansiddique authored and russellb committed Jan 26, 2017
1 parent 96fee5e commit 213615b
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Showing 2 changed files with 108 additions and 13 deletions.
37 changes: 33 additions & 4 deletions ovn/northd/ovn-northd.c
View file
Expand Up @@ -2115,7 +2115,8 @@ lsp_is_up(const struct nbrec_logical_switch_port *lsp)

static bool
build_dhcpv4_action(struct ovn_port *op, ovs_be32 offer_ip,
struct ds *options_action, struct ds *response_action)
struct ds *options_action, struct ds *response_action,
struct ds *ipv4_addr_match)
{
if (!op->nbsp->dhcpv4_options) {
/* CMS has disabled native DHCPv4 for this lport. */
Expand Down Expand Up @@ -2185,6 +2186,9 @@ build_dhcpv4_action(struct ovn_port *op, ovs_be32 offer_ip,
"output;",
server_mac, IP_ARGS(offer_ip), server_ip);

ds_put_format(ipv4_addr_match,
"ip4.src == "IP_FMT" && ip4.dst == {%s, 255.255.255.255}",
IP_ARGS(offer_ip), server_ip);
smap_destroy(&dhcpv4_options);
return true;
}
Expand Down Expand Up @@ -3085,9 +3089,10 @@ build_lswitch_flows(struct hmap *datapaths, struct hmap *ports,
for (size_t j = 0; j < op->lsp_addrs[i].n_ipv4_addrs; j++) {
struct ds options_action = DS_EMPTY_INITIALIZER;
struct ds response_action = DS_EMPTY_INITIALIZER;
struct ds ipv4_addr_match = DS_EMPTY_INITIALIZER;
if (build_dhcpv4_action(
op, op->lsp_addrs[i].ipv4_addrs[j].addr,
&options_action, &response_action)) {
&options_action, &response_action, &ipv4_addr_match)) {
struct ds match = DS_EMPTY_INITIALIZER;
ds_put_format(
&match, "inport == %s && eth.src == %s && "
Expand All @@ -3098,15 +3103,39 @@ build_lswitch_flows(struct hmap *datapaths, struct hmap *ports,
ovn_lflow_add(lflows, op->od, S_SWITCH_IN_DHCP_OPTIONS,
100, ds_cstr(&match),
ds_cstr(&options_action));
ds_clear(&match);
/* Allow ip4.src = OFFER_IP and
* ip4.dst = {SERVER_IP, 255.255.255.255} for the below
* cases
* - When the client wants to renew the IP by sending
* the DHCPREQUEST to the server ip.
* - When the client wants to renew the IP by
* broadcasting the DHCPREQUEST.
*/
ds_put_format(
&match, "inport == %s && eth.src == %s && "
"%s && udp.src == 68 && udp.dst == 67", op->json_key,
op->lsp_addrs[i].ea_s, ds_cstr(&ipv4_addr_match));

ovn_lflow_add(lflows, op->od, S_SWITCH_IN_DHCP_OPTIONS,
100, ds_cstr(&match),
ds_cstr(&options_action));
ds_clear(&match);

/* If REGBIT_DHCP_OPTS_RESULT is set, it means the
* put_dhcp_opts action is successful */
ds_put_cstr(&match, " && "REGBIT_DHCP_OPTS_RESULT);
* put_dhcp_opts action is successful. */
ds_put_format(
&match, "inport == %s && eth.src == %s && "
"ip4 && udp.src == 68 && udp.dst == 67"
" && "REGBIT_DHCP_OPTS_RESULT, op->json_key,
op->lsp_addrs[i].ea_s);
ovn_lflow_add(lflows, op->od, S_SWITCH_IN_DHCP_RESPONSE,
100, ds_cstr(&match),
ds_cstr(&response_action));
ds_destroy(&match);
ds_destroy(&options_action);
ds_destroy(&response_action);
ds_destroy(&ipv4_addr_match);
break;
}
}
Expand Down
84 changes: 75 additions & 9 deletions tests/ovn.at
View file
Expand Up @@ -3705,8 +3705,17 @@ as hv1 ovs-vsctl show
# This shell function sends a DHCP request packet
# test_dhcp INPORT SRC_MAC DHCP_TYPE OFFER_IP ...
test_dhcp() {
local inport=$1 src_mac=$2 dhcp_type=$3 offer_ip=$4
local request=ffffffffffff${src_mac}080045100110000000008011000000000000ffffffff
local inport=$1 src_mac=$2 dhcp_type=$3 offer_ip=$4 use_ip=$5
shift; shift; shift; shift; shift;
if test $use_ip != 0; then
src_ip=$1
dst_ip=$2
shift; shift;
else
src_ip=`ip_to_hex 0 0 0 0`
dst_ip=`ip_to_hex 255 255 255 255`
fi
local request=ffffffffffff${src_mac}0800451001100000000080110000${src_ip}${dst_ip}
# udp header and dhcp header
request=${request}0044004300fc0000
request=${request}010106006359aa760000000000000000000000000000000000000000${src_mac}
Expand All @@ -3726,7 +3735,7 @@ test_dhcp() {
request=${request}3501${dhcp_type}ff

if test $offer_ip != 0; then
local srv_mac=$5 srv_ip=$6 expected_dhcp_opts=$7
local srv_mac=$1 srv_ip=$2 expected_dhcp_opts=$3
# total IP length will be the IP length of the request packet
# (which is 272 in our case) + 8 (padding bytes) + (expected_dhcp_opts / 2)
ip_len=`expr 280 + ${#expected_dhcp_opts} / 2`
Expand Down Expand Up @@ -3762,7 +3771,6 @@ test_dhcp() {
reply=${reply}3501${dhcp_reply_type}${expected_dhcp_opts}00000000ff00000000
echo $reply >> $inport.expected
else
shift; shift; shift; shift;
for outport; do
echo $request >> $outport.expected
done
Expand Down Expand Up @@ -3808,7 +3816,7 @@ as hv1 ovs-ofctl dump-flows br-int
offer_ip=`ip_to_hex 10 0 0 4`
server_ip=`ip_to_hex 10 0 0 1`
expected_dhcp_opts=330400000e100104ffffff0003040a00000136040a000001
test_dhcp 1 f00000000001 01 $offer_ip ff1000000001 $server_ip $expected_dhcp_opts
test_dhcp 1 f00000000001 01 $offer_ip 0 ff1000000001 $server_ip $expected_dhcp_opts

# NXT_RESUMEs should be 1.
OVS_WAIT_UNTIL([test 1 = `cat ofctl_monitor*.log | grep -c NXT_RESUME`])
Expand All @@ -3831,7 +3839,7 @@ rm -f 2.expected
offer_ip=`ip_to_hex 10 0 0 6`
server_ip=`ip_to_hex 10 0 0 1`
expected_dhcp_opts=330400000e100104ffffff0003040a00000136040a000001
test_dhcp 2 f00000000002 03 $offer_ip ff1000000001 $server_ip $expected_dhcp_opts
test_dhcp 2 f00000000002 03 $offer_ip 0 ff1000000001 $server_ip $expected_dhcp_opts

# NXT_RESUMEs should be 2.
OVS_WAIT_UNTIL([test 2 = `cat ofctl_monitor*.log | grep -c NXT_RESUME`])
Expand All @@ -3853,7 +3861,7 @@ rm -f 2.expected
# ls1-lp1 (vif1-tx.pcap) should receive the DHCPv4 request packet twice,
# one from ovn-controller and the other from "ovs-ofctl resume."
offer_ip=0
test_dhcp 2 f00000000002 08 $offer_ip 1 1
test_dhcp 2 f00000000002 08 $offer_ip 0 1 1

# NXT_RESUMEs should be 3.
OVS_WAIT_UNTIL([test 3 = `cat ofctl_monitor*.log | grep -c NXT_RESUME`])
Expand All @@ -3869,18 +3877,76 @@ rm -f 2.expected
# Send DHCPv4 packet on ls2-lp1. It doesn't have any DHCPv4 options defined.
# ls2-lp2 (vif4-tx.pcap) should receive the DHCPv4 request packet once.

test_dhcp 3 f00000000003 01 0 4
test_dhcp 3 f00000000003 01 0 4 0

# Send DHCPv4 packet on ls2-lp2. "router" DHCPv4 option is not defined for
# this lport.
test_dhcp 4 f00000000004 01 0 3
test_dhcp 4 f00000000004 01 0 3 0

# NXT_RESUMEs should be 3.
OVS_WAIT_UNTIL([test 3 = `cat ofctl_monitor*.log | grep -c NXT_RESUME`])

OVN_CHECK_PACKETS([hv1/vif3-tx.pcap], [3.expected])
OVN_CHECK_PACKETS([hv1/vif4-tx.pcap], [4.expected])

# Send DHCPREQUEST with ip4.src set to 10.0.0.6 and ip4.dst set to 10.0.0.1.
offer_ip=`ip_to_hex 10 0 0 6`
server_ip=`ip_to_hex 10 0 0 1`
expected_dhcp_opts=330400000e100104ffffff0003040a00000136040a000001
src_ip=$offer_ip
dst_ip=$server_ip
test_dhcp 2 f00000000002 03 $offer_ip 1 $src_ip $dst_ip ff1000000001 $server_ip $expected_dhcp_opts

# NXT_RESUMEs should be 4.
OVS_WAIT_UNTIL([test 4 = `cat ofctl_monitor*.log | grep -c NXT_RESUME`])

$PYTHON "$top_srcdir/utilities/ovs-pcap.in" hv1/vif2-tx.pcap > 2.packets
cat 2.expected | cut -c -48 > expout
AT_CHECK([cat 2.packets | cut -c -48], [0], [expout])
# Skipping the IPv4 checksum.
cat 2.expected | cut -c 53- > expout
AT_CHECK([cat 2.packets | cut -c 53-], [0], [expout])

reset_pcap_file hv1-vif1 hv1/vif1
reset_pcap_file hv1-vif2 hv1/vif2
rm -f 1.expected
rm -f 2.expected

# Send DHCPREQUEST with ip4.src set to 10.0.0.6 and ip4.dst set to 255.255.255.255.
offer_ip=`ip_to_hex 10 0 0 6`
server_ip=`ip_to_hex 10 0 0 1`
expected_dhcp_opts=330400000e100104ffffff0003040a00000136040a000001
src_ip=$offer_ip
dst_ip=`ip_to_hex 255 255 255 255`
test_dhcp 2 f00000000002 03 $offer_ip 1 $src_ip $dst_ip ff1000000001 $server_ip $expected_dhcp_opts

# NXT_RESUMEs should be 5.
OVS_WAIT_UNTIL([test 5 = `cat ofctl_monitor*.log | grep -c NXT_RESUME`])

$PYTHON "$top_srcdir/utilities/ovs-pcap.in" hv1/vif2-tx.pcap > 2.packets
cat 2.expected | cut -c -48 > expout
AT_CHECK([cat 2.packets | cut -c -48], [0], [expout])
# Skipping the IPv4 checksum.
cat 2.expected | cut -c 53- > expout
AT_CHECK([cat 2.packets | cut -c 53-], [0], [expout])

reset_pcap_file hv1-vif1 hv1/vif1
reset_pcap_file hv1-vif2 hv1/vif2
rm -f 1.expected
rm -f 2.expected

# Send DHCPREQUEST with ip4.src set to 10.0.0.6 and ip4.dst set to 10.0.0.4.
# The packet should not be received by ovn-controller.
src_ip=`ip_to_hex 10 0 0 6`
dst_ip=`ip_to_hex 10 0 0 4`
test_dhcp 2 f00000000002 03 0 1 $src_ip $dst_ip 1

# NXT_RESUMEs should be 5.
OVS_WAIT_UNTIL([test 5 = `cat ofctl_monitor*.log | grep -c NXT_RESUME`])

# vif1-tx.pcap should have received the DHCPv4 request packet
OVN_CHECK_PACKETS([hv1/vif1-tx.pcap], [1.expected])

as hv1
OVS_APP_EXIT_AND_WAIT([ovn-controller])
OVS_APP_EXIT_AND_WAIT([ovs-vswitchd])
Expand Down

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