ipf: Fix the over-sized reassembly.

Fix the coredump of ovs_assert, The backtrace is as follows,
 #8 0x0000561ee52084bb in ovs_assert_failure (where=<>, function=<>, condition=<>) at ../lib/util.c:89
 #9 0x0000561ee50f8ab2 in dp_packet_set_size (b=<>, v=<>) at ../lib/dp-packet.h:687
 #10 dp_packet_set_size (v=<>, b=0x7f7f88143e80) at ../lib/dp-packet.h:687
 #11 dp_packet_put_uninit (size=395, b=0x7f7f88143e80) at ../lib/dp-packet.c:355
 #12 dp_packet_put (b=0x7f7f88143e80, p=0x7f7f88143ce2, size=395) at ../lib/dp-packet.c:376
 #13 0x0000561ee512c147 in ipf_reassemble_v4_frags (ipf_list=0x7f7f88110810) at ../lib/ipf.c:430

The mbuf data_len is a uint16_t field, which includes the ether header.
So does IPv6.

Fixes: 4ea9669 ("Userspace datapath: Add fragmentation handling.")

Acked-by: Mike Pattrick <mkp@redhat.com>
Signed-off-by: Faicker Mo <faicker.mo@zenlayer.com>
Signed-off-by: Aaron Conole <aconole@redhat.com>

Author: faicker-zl

lib/ipf.c

@@ -410,11 +410,12 @@ ipf_reassemble_v4_frags(struct ipf_list *ipf_list)
     dp_packet_set_size(pkt, dp_packet_size(pkt) - dp_packet_l2_pad_size(pkt));
     struct ip_header *l3 = dp_packet_l3(pkt);
     int len = ntohs(l3->ip_tot_len);
+    int orig_len = dp_packet_size(pkt);
 
     int rest_len = frag_list[ipf_list->last_inuse_idx].end_data_byte -
                    frag_list[1].start_data_byte + 1;
 
-    if (len + rest_len > IPV4_PACKET_MAX_SIZE) {
+    if (orig_len + rest_len > IPV4_PACKET_MAX_SIZE) {
         ipf_print_reass_packet(
             "Unsupported big reassembled v4 packet; v4 hdr:", l3);
         dp_packet_delete(pkt);
@@ -457,11 +458,12 @@ ipf_reassemble_v6_frags(struct ipf_list *ipf_list)
     dp_packet_set_size(pkt, dp_packet_size(pkt) - dp_packet_l2_pad_size(pkt));
     struct  ovs_16aligned_ip6_hdr *l3 = dp_packet_l3(pkt);
     int pl = ntohs(l3->ip6_plen) - sizeof(struct ovs_16aligned_ip6_frag);
+    int orig_len = dp_packet_size(pkt);
 
     int rest_len = frag_list[ipf_list->last_inuse_idx].end_data_byte -
                    frag_list[1].start_data_byte + 1;
 
-    if (pl + rest_len > IPV6_PACKET_MAX_DATA) {
+    if (orig_len + rest_len > IPV6_PACKET_MAX_DATA) {
         ipf_print_reass_packet(
              "Unsupported big reassembled v6 packet; v6 hdr:", l3);
         dp_packet_delete(pkt);

tests/system-kmod-macros.at

@@ -193,6 +193,14 @@ m4_define([DPCTL_CHECK_FRAGMENTATION_FAIL],
 
 ])
 
+# OVS_CHECK_FRAG_LARGE
+#
+# This check isn't valid for kernel
+m4_define([OVS_CHECK_FRAG_LARGE],
+[
+
+])
+
 # OVS_CHECK_MIN_KERNEL([minversion], [minsublevel])
 #
 # Skip test if kernel version falls below minversion.minsublevel

tests/system-traffic.at

@@ -3854,7 +3854,11 @@ NS_CHECK_EXEC([at_ns0], [ping -s 3200 -q -c 3 -i 0.3 -W 2 10.1.1.2 | FORMAT_PING
 dnl Check userspace conntrack fragmentation counters.
 DPCTL_CHECK_FRAGMENTATION_PASS()
 
-OVS_TRAFFIC_VSWITCHD_STOP
+dnl Ipv4 max packet size fragmentation dropped.
+NS_EXEC([at_ns0], [ping -s 65507 -q -c 1 -W 0.5 10.1.1.2])
+OVS_CHECK_FRAG_LARGE()
+
+OVS_TRAFFIC_VSWITCHD_STOP(["/Unsupported big reassembled v4 packet/d"])
 AT_CLEANUP
 
 AT_SETUP([conntrack - IPv4 fragmentation expiry])
@@ -4147,7 +4151,11 @@ NS_CHECK_EXEC([at_ns0], [ping6 -s 3200 -q -c 3 -i 0.3 -W 2 fc00::2 | FORMAT_PING
 3 packets transmitted, 3 received, 0% packet loss, time 0ms
 ])
 
-OVS_TRAFFIC_VSWITCHD_STOP
+dnl Ipv6 max packet size fragmentation dropped.
+NS_EXEC([at_ns0], [ping6 -s 65487 -q -c 1 -W 0.5 fc00::2])
+OVS_CHECK_FRAG_LARGE()
+
+OVS_TRAFFIC_VSWITCHD_STOP(["/Unsupported big reassembled v6 packet/d"])
 AT_CLEANUP
 
 AT_SETUP([conntrack - IPv6 fragmentation expiry])

tests/system-userspace-macros.at

@@ -295,6 +295,14 @@ AT_CHECK([ovs-appctl dpctl/ipf-get-status -m | FORMAT_FRAG_LIST()], [], [dnl
 ])
 ])
 
+# OVS_CHECK_FRAG_LARGE()
+#
+# The userspace needs to check that ipf larger fragments have occurred.
+m4_define([OVS_CHECK_FRAG_LARGE],
+[
+    OVS_WAIT_UNTIL([grep -Eq 'Unsupported big reassembled (v4|v6) packet' ovs-vswitchd.log])
+])
+
 # OVS_CHECK_MIN_KERNEL([minversion], [maxversion])
 #
 # The userspace skips all tests that check kernel version.