While offloading header modifications to TC, OVS is using {TCA_PEDIT} +
{TCA_CSUM} combination as that it the only way to represent header
rewrite. However, {TCA_CSUM} is unable to calculate L4 checksums for
IP fragments.
Since TC already applies fragmentation bit masking, this patch simply
needs to prevent these packets from being processed through TC.
Signed-off-by: Eelco Chaudron <[email protected]>
---
lib/netdev-offload-tc.c | 32 +++++++++++++++++++++
tests/system-traffic.at | 62 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 94 insertions(+)
diff --git a/lib/netdev-offload-tc.c b/lib/netdev-offload-tc.c
index 921d52317..7e915d419 100644
--- a/lib/netdev-offload-tc.c
+++ b/lib/netdev-offload-tc.c
@@ -1488,6 +1488,30 @@ parse_put_flow_ct_action(struct tc_flower *flower,
return 0;
}
+static bool
+will_tc_add_l4_checksum(struct tc_flower *flower, int type)
+{
+ /* This function returns true if the tc layer will add a l4 checksum action
+ * for this set action. Refer to the csum_update_flag() function for
+ * detailed logic. Note that even the kernel only supports updating TCP,
+ * UDP and ICMPv6. */
+ switch (type) {
+ case OVS_KEY_ATTR_IPV4:
+ case OVS_KEY_ATTR_IPV6:
+ case OVS_KEY_ATTR_TCP:
+ case OVS_KEY_ATTR_UDP:
+ switch (flower->key.ip_proto) {
+ case IPPROTO_TCP:
+ case IPPROTO_UDP:
+ case IPPROTO_ICMPV6:
+ case IPPROTO_UDPLITE:
+ return true;
+ }
+ break;
+ }
+ return false;
+}
+
static int
parse_put_flow_set_masked_action(struct tc_flower *flower,
struct tc_action *action,
@@ -1520,6 +1544,14 @@ parse_put_flow_set_masked_action(struct tc_flower
*flower,
return EOPNOTSUPP;
}
+ if (flower->key.flags & TCA_FLOWER_KEY_FLAGS_IS_FRAGMENT
+ && will_tc_add_l4_checksum(flower, type)) {
+ VLOG_DBG_RL(&rl, "set action type %d not supported on fragments "
+ "due to checksum limitation", type);
+ ofpbuf_uninit(&set_buf);
+ return EOPNOTSUPP;
+ }
+
for (i = 0; i < ARRAY_SIZE(set_flower_map[type]); i++) {
struct netlink_field *f = &set_flower_map[type][i];
diff --git a/tests/system-traffic.at b/tests/system-traffic.at
index bd7647cbe..d06d2f66a 100644
--- a/tests/system-traffic.at
+++ b/tests/system-traffic.at
@@ -8977,3 +8977,65 @@ OVS_WAIT_UNTIL([cat p2.pcap | grep -E "0x0050: *0000
*0000 *5002 *2000 *b85e *00
OVS_TRAFFIC_VSWITCHD_STOP
AT_CLEANUP
+
+
+AT_SETUP([datapath - IP mod_nw_src/set_field on fragments])
+AT_SKIP_IF([test $HAVE_TCPDUMP = no])
+OVS_TRAFFIC_VSWITCHD_START()
+
+ADD_NAMESPACES(at_ns0, at_ns1)
+
+ADD_VETH(p0, at_ns0, br0, "10.1.1.1/24", 36:b1:ee:7c:01:03)
+ADD_VETH(p1, at_ns1, br0, "10.1.1.2/24", 36:b1:ee:7c:01:02)
+
+AT_DATA([flows.txt], [dnl
+ in_port=ovs-p0,ip,nw_src=10.1.1.1 actions=mod_nw_src=11.1.1.1,ovs-p1
+ in_port=ovs-p0,ipv6,ipv6_src=fc00::1
actions=set_field:fc00::100->ipv6_src,ovs-p1
+])
+
+AT_CHECK([ovs-ofctl del-flows br0])
+AT_CHECK([ovs-ofctl -Oopenflow13 add-flows br0 flows.txt])
+
+NETNS_DAEMONIZE([at_ns1], [tcpdump -l -nn -xx -U -i p1 > p1.out],
+ [tcpdump.pid])
+sleep 1
+
+dnl We send each packet multiple times, ones for learning which will flow
+dnl through the used datapath for learning, and the others will go through the
+dnl actuall datapath.
+for i in 1 2 3 4 5; do
+ NS_CHECK_EXEC([at_ns0], [$PYTHON3 $srcdir/sendpkt.py p0 \
+ 36 b1 ee 7c 01 02 36 b1 ee 7c 01 03 08 00 45 00 00 26 00 01 20 00 40 11 \
+ 44 c2 0a 01 01 01 0a 01 01 02 0b c4 08 84 00 26 e9 64 01 02 03 04 05 06 \
+ 07 08 09 0a > /dev/null])
+done
+
+OVS_WAIT_UNTIL([test $(grep -c -E \
+ "0x0000: *36b1 *ee7c *0102 *36b1 *ee7c *0103 *0800 *4500" p1.out) -eq 5])
+OVS_WAIT_UNTIL([test $(grep -c -E \
+ "0x0010: *0026 *0001 *2000 *4011 *43c2 *0b01 *0101 *0a01" p1.out) -eq 5])
+OVS_WAIT_UNTIL([test $(grep -c -E \
+ "0x0020: *0102 *0bc4 *0884 *0026 *e864 *0102 *0304 *0506" p1.out) -eq 5])
+
+dnl Repeat similar test with IPv6.
+for i in 1 2 3 4 5; do
+ NS_CHECK_EXEC([at_ns0], [$PYTHON3 $srcdir/sendpkt.py p0 \
+ 36 b1 ee 7c 01 02 36 b1 ee 7c 01 03 86 dd 60 00 00 00 00 18 2c 40 fc 00 \
+ 00 00 00 00 00 00 00 00 00 00 00 00 00 01 fc 00 00 00 00 00 00 00 00 00 \
+ 00 00 00 00 00 02 11 00 00 01 23 16 ab 36 0b c4 08 84 00 26 07 65 01 02 \
+ 03 04 05 06 07 08 > /dev/null])
+done
+
+OVS_WAIT_UNTIL([test $(grep -c -E \
+ "0x0000: *36b1 *ee7c *0102 *36b1 *ee7c *0103 *86dd *6000" p1.out) -eq 5])
+OVS_WAIT_UNTIL([test $(grep -c -E \
+ "0x0010: *0000 *0018 *2c40 *fc00 *0000 *0000 *0000 *0000" p1.out) -eq 5])
+OVS_WAIT_UNTIL([test $(grep -c -E \
+ "0x0020: *0000 *0000 *0100 *fc00 *0000 *0000 *0000 *0000" p1.out) -eq 5])
+OVS_WAIT_UNTIL([test $(grep -c -E \
+ "0x0030: *0000 *0000 *0002 *1100 *0001 *2316 *ab36 *0bc4" p1.out) -eq 5])
+OVS_WAIT_UNTIL([test $(grep -c -E \
+ "0x0040: *0884 *0026 *0666 *0102 *0304 *0506 *0708" p1.out) -eq 5])
+
+OVS_TRAFFIC_VSWITCHD_STOP
+AT_CLEANUP
--
2.43.0
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