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https://github.com/openvswitch/ovs
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ovs-ofctl: Implement compose-packet --bare [--bad-csum].
With --bare, it will produce a bare hexified payload with no spaces or offset indicators inserted, which is useful in tests to produce frames to pass to e.g. `ovs-ofctl receive`. With --bad-csum, it will produce a frame that has an invalid IP checksum (applicable to IPv4 only because IPv6 doesn't have checksums.) The command is now more useful in tests, where we may need to produce hex frame payloads to compare observed frames against. As an example of the tool use, a single test case is converted to it. The test uses both normal --bare and --bad-csum behaviors of the command, confirming they work as advertised. Acked-by: Simon Horman <horms@ovn.org> Signed-off-by: Ihar Hrachyshka <ihrachys@redhat.com> Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
This commit is contained in:
Ihar Hrachyshka
committed by
Ilya Maximets
Ilya Maximets
parent
3e0d8d1f4b
commit
c62b4ac8f8
17
lib/flow.c
17
lib/flow.c
@@ -3306,6 +3306,8 @@ packet_expand(struct dp_packet *p, const struct flow *flow, size_t size)
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* (This is useful only for testing, obviously, and the packet isn't really
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* valid. Lots of fields are just zeroed.)
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*
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* If 'bad_csum' is true, the final IP checksum is invalid.
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*
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* For packets whose protocols can encapsulate arbitrary L7 payloads, 'l7' and
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* 'l7_len' determine that payload:
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*
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@@ -3318,7 +3320,7 @@ packet_expand(struct dp_packet *p, const struct flow *flow, size_t size)
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* from 'l7'. */
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void
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flow_compose(struct dp_packet *p, const struct flow *flow,
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const void *l7, size_t l7_len)
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const void *l7, size_t l7_len, bool bad_csum)
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{
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/* Add code to this function (or its callees) for emitting new fields or
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* protocols. (This isn't essential, so it can be skipped for initial
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@@ -3370,7 +3372,18 @@ flow_compose(struct dp_packet *p, const struct flow *flow,
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/* Checksum has already been zeroed by put_zeros call. */
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ip->ip_csum = csum(ip, sizeof *ip);
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dp_packet_ol_set_ip_csum_good(p);
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if (bad_csum) {
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/*
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* Internet checksum is a sum complement to zero, so any other
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* value will result in an invalid checksum. Here, we flip one
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* bit.
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*/
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ip->ip_csum ^= (OVS_FORCE ovs_be16) 0x1;
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dp_packet_ip_checksum_bad(p);
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} else {
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dp_packet_ol_set_ip_csum_good(p);
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}
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pseudo_hdr_csum = packet_csum_pseudoheader(ip);
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flow_compose_l4_csum(p, flow, pseudo_hdr_csum);
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} else if (flow->dl_type == htons(ETH_TYPE_IPV6)) {
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@@ -127,7 +127,7 @@ void flow_set_mpls_bos(struct flow *, int idx, uint8_t stack);
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void flow_set_mpls_lse(struct flow *, int idx, ovs_be32 lse);
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void flow_compose(struct dp_packet *, const struct flow *,
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const void *l7, size_t l7_len);
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const void *l7, size_t l7_len, bool bad_csum);
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void packet_expand(struct dp_packet *, const struct flow *, size_t size);
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bool parse_ipv6_ext_hdrs(const void **datap, size_t *sizep, uint8_t *nw_proto,
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@@ -1769,7 +1769,7 @@ eth_from_flow_str(const char *s, size_t packet_size,
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packet = dp_packet_new(0);
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if (packet_size) {
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flow_compose(packet, flow, NULL, 0);
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flow_compose(packet, flow, NULL, 0, false);
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if (dp_packet_size(packet) < packet_size) {
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packet_expand(packet, flow, packet_size);
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} else if (dp_packet_size(packet) > packet_size){
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@@ -1777,7 +1777,7 @@ eth_from_flow_str(const char *s, size_t packet_size,
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packet = NULL;
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}
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} else {
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flow_compose(packet, flow, NULL, 64);
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flow_compose(packet, flow, NULL, 64, false);
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}
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ofpbuf_uninit(&odp_key);
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@@ -440,7 +440,7 @@ parse_flow_and_packet(int argc, const char *argv[],
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if (generate_packet) {
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/* Generate a packet, as requested. */
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packet = dp_packet_new(0);
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flow_compose(packet, flow, l7, l7_len);
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flow_compose(packet, flow, l7, l7_len, false);
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} else if (packet) {
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/* Use the metadata from the flow and the packet argument to
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* reconstruct the flow. */
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@@ -1255,7 +1255,7 @@ check_ct_eventmask(struct dpif_backer *backer)
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/* Compose a dummy UDP packet. */
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dp_packet_init(&packet, 0);
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flow_compose(&packet, &flow, NULL, 64);
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flow_compose(&packet, &flow, NULL, 64, false);
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/* Execute the actions. On older datapaths this fails with EINVAL, on
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* newer datapaths it succeeds. */
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@@ -1348,7 +1348,7 @@ check_ct_timeout_policy(struct dpif_backer *backer)
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/* Compose a dummy UDP packet. */
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dp_packet_init(&packet, 0);
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flow_compose(&packet, &flow, NULL, 64);
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flow_compose(&packet, &flow, NULL, 64, false);
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/* Execute the actions. On older datapaths this fails with EINVAL, on
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* newer datapaths it succeeds. */
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@@ -746,19 +746,25 @@ OVS_VSWITCHD_START(
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# Modify the ip_dst addr to force changing the IP csum.
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AT_CHECK([ovs-ofctl add-flow br1 in_port=p1,actions=mod_nw_dst:192.168.1.1,output:p2])
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flow_s="\
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eth_src=8a:bf:7e:2f:05:84,eth_dst=0a:8f:39:4f:e0:73,dl_type=0x0800,\
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nw_src=192.168.123.2,nw_dst=192.168.123.1,nw_proto=6,nw_ttl=64,nw_frag=no,\
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tp_src=54392,tp_dst=5201,tcp_flags=ack"
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good_frame=$(ovs-ofctl compose-packet --bare "${flow_s}")
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# Check if no offload remains ok.
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AT_CHECK([ovs-vsctl set Interface p2 options:tx_pcap=p2.pcap])
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AT_CHECK([ovs-vsctl set Interface p1 options:ol_ip_csum=false])
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AT_CHECK([ovs-vsctl set Interface p1 options:ol_ip_csum_set_good=false])
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AT_CHECK([ovs-appctl netdev-dummy/receive p1 \
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0a8f394fe0738abf7e2f058408004500003433e0400040068f8fc0a87b02c0a87b01d4781451a962ad5417ed297b801000e547fd00000101080a2524d2345c7fe1c4
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])
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AT_CHECK([ovs-appctl netdev-dummy/receive p1 ${good_frame}])
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# Checksum should change to 0x990 with ip_dst changed to 192.168.1.1
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# by the datapath while processing the packet.
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flow_expected=$(echo "${flow_s}" | sed 's/192.168.123.1/192.168.1.1/g')
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good_expected=$(ovs-ofctl compose-packet --bare "${flow_expected}")
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AT_CHECK([ovs-pcap p2.pcap > p2.pcap.txt 2>&1])
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AT_CHECK([tail -n 1 p2.pcap.txt], [0], [dnl
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0a8f394fe0738abf7e2f058408004500003433e0400040060990c0a87b02c0a80101d4781451a962ad5417ed297b801000e5c1fd00000101080a2524d2345c7fe1c4
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AT_CHECK_UNQUOTED([tail -n 1 p2.pcap.txt], [0], [${good_expected}
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])
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# Check if packets entering the datapath with csum offloading
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@@ -766,12 +772,9 @@ AT_CHECK([tail -n 1 p2.pcap.txt], [0], [dnl
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# in the datapath and not by the netdev.
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AT_CHECK([ovs-vsctl set Interface p1 options:ol_ip_csum=false])
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AT_CHECK([ovs-vsctl set Interface p1 options:ol_ip_csum_set_good=true])
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AT_CHECK([ovs-appctl netdev-dummy/receive p1 \
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0a8f394fe0738abf7e2f058408004500003433e0400040068f8fc0a87b02c0a87b01d4781451a962ad5417ed297b801000e547fd00000101080a2524d2345c7fe1c4
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])
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AT_CHECK([ovs-appctl netdev-dummy/receive p1 ${good_frame}])
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AT_CHECK([ovs-pcap p2.pcap > p2.pcap.txt 2>&1])
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AT_CHECK([tail -n 1 p2.pcap.txt], [0], [dnl
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0a8f394fe0738abf7e2f058408004500003433e0400040060990c0a87b02c0a80101d4781451a962ad5417ed297b801000e5c1fd00000101080a2524d2345c7fe1c4
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AT_CHECK_UNQUOTED([tail -n 1 p2.pcap.txt], [0], [${good_expected}
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])
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# Check if packets entering the datapath with csum offloading
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@@ -779,36 +782,30 @@ AT_CHECK([tail -n 1 p2.pcap.txt], [0], [dnl
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# by the datapath.
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AT_CHECK([ovs-vsctl set Interface p1 options:ol_ip_csum=true])
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AT_CHECK([ovs-vsctl set Interface p1 options:ol_ip_csum_set_good=true])
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AT_CHECK([ovs-appctl netdev-dummy/receive p1 \
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0a8f394fe0738abf7e2f058408004500003433e0400040068f8fc0a87b02c0a87b01d4781451a962ad5417ed297b801000e547fd00000101080a2524d2345c7fe1c4
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AT_CHECK([ovs-appctl netdev-dummy/receive p1 ${good_frame}
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])
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AT_CHECK([ovs-pcap p2.pcap > p2.pcap.txt 2>&1])
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AT_CHECK([tail -n 1 p2.pcap.txt], [0], [dnl
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0a8f394fe0738abf7e2f058408004500003433e0400040060990c0a87b02c0a80101d4781451a962ad5417ed297b801000e5c1fd00000101080a2524d2345c7fe1c4
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AT_CHECK_UNQUOTED([tail -n 1 p2.pcap.txt], [0], [${good_expected}
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])
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# Push a packet with bad csum and offloading disabled to check
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# if the datapath updates the csum, but does not fix the issue.
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bad_frame=$(ovs-ofctl compose-packet --bare --bad-csum "${flow_s}")
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AT_CHECK([ovs-vsctl set Interface p1 options:ol_ip_csum=false])
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AT_CHECK([ovs-vsctl set Interface p1 options:ol_ip_csum_set_good=false])
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AT_CHECK([ovs-appctl netdev-dummy/receive p1 \
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0a8f394fe0738abf7e2f058408004500003433e0400040068f03c0a87b02c0a87b01d4781451a962ad5417ed297b801000e547fd00000101080a2524d2345c7fe1c4
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])
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AT_CHECK([ovs-appctl netdev-dummy/receive p1 ${bad_frame}])
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AT_CHECK([ovs-pcap p2.pcap > p2.pcap.txt 2>&1])
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AT_CHECK([tail -n 1 p2.pcap.txt], [0], [dnl
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0a8f394fe0738abf7e2f058408004500003433e0400040060904c0a87b02c0a80101d4781451a962ad5417ed297b801000e5c1fd00000101080a2524d2345c7fe1c4
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bad_expected=$(ovs-ofctl compose-packet --bare --bad-csum "${flow_expected}")
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AT_CHECK_UNQUOTED([tail -n 1 p2.pcap.txt], [0], [${bad_expected}
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])
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# Push a packet with bad csum and offloading enabled to check
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# if the driver updates and fixes the csum.
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AT_CHECK([ovs-vsctl set Interface p1 options:ol_ip_csum=true])
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AT_CHECK([ovs-vsctl set Interface p1 options:ol_ip_csum_set_good=true])
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AT_CHECK([ovs-appctl netdev-dummy/receive p1 \
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0a8f394fe0738abf7e2f058408004500003433e0400040068f03c0a87b02c0a87b01d4781451a962ad5417ed297b801000e547fd00000101080a2524d2345c7fe1c4
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])
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AT_CHECK([ovs-appctl netdev-dummy/receive p1 ${bad_frame}])
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AT_CHECK([ovs-pcap p2.pcap > p2.pcap.txt 2>&1])
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AT_CHECK([tail -n 1 p2.pcap.txt], [0], [dnl
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0a8f394fe0738abf7e2f058408004500003433e0400040060990c0a87b02c0a80101d4781451a962ad5417ed297b801000e5c1fd00000101080a2524d2345c7fe1c4
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AT_CHECK_UNQUOTED([tail -n 1 p2.pcap.txt], [0], [${good_expected}
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])
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OVS_VSWITCHD_STOP
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AT_CLEANUP
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@@ -154,6 +154,12 @@ static int show_stats = 1;
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/* --pcap: Makes "compose-packet" print a pcap on stdout. */
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static int print_pcap = 0;
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/* --bare: Makes "compose-packet" print a bare hexified payload. */
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static int print_bare = 0;
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/* -bad-csum: Makes "compose-packet" generate an invalid checksum. */
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static int bad_csum = 0;
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/* --raw: Makes "ofp-print" read binary data from stdin. */
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static int raw = 0;
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@@ -243,6 +249,8 @@ parse_options(int argc, char *argv[])
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{"color", optional_argument, NULL, OPT_COLOR},
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{"may-create", no_argument, NULL, OPT_MAY_CREATE},
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{"pcap", no_argument, &print_pcap, 1},
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{"bare", no_argument, &print_bare, 1},
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{"bad-csum", no_argument, &bad_csum, 1},
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{"raw", no_argument, &raw, 1},
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{"read-only", no_argument, NULL, OPT_READ_ONLY},
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DAEMON_LONG_OPTIONS,
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@@ -4948,20 +4956,33 @@ ofctl_parse_key_value(struct ovs_cmdl_context *ctx)
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}
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}
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/* "compose-packet [--pcap] FLOW [L7]": Converts the OpenFlow flow
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* specification FLOW to a packet with flow_compose() and prints the hex bytes
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* in the packet on stdout. Also verifies that the flow extracted from that
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* packet matches the original FLOW.
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/* "compose-packet [--pcap|--bare] [--bad-csum] FLOW [L7]": Converts the
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* OpenFlow flow specification FLOW to a packet with flow_compose() and prints
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* the hex bytes of the packet, with offsets, to stdout.
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*
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* With --pcap, prints the packet to stdout instead as a pcap file, so that you
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* can do something like "ovs-ofctl --pcap compose-packet udp | tcpdump -vvvv
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* -r-" to use another tool to dump the packet contents.
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* With --pcap, prints the packet in pcap format, so that you can do something
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* like "ovs-ofctl --pcap compose-packet udp | tcpdump -vvvv -r-" to use
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* another tool to dump the packet contents.
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*
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* With --bare, prints the packet as a single bare hex string with no
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* spaces or offsets, so that you can pass the result directly to e.g.
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* "ovs-appctl netdev-dummy/receive vif $(ovs-ofctl compose-packet --bare
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* FLOW)"
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*
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* With --bad-csum, produces a packet with an invalid IP checksum. (For IPv4.)
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*
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* Regardless of the mode, the command also verifies that the flow extracted
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* from that packet matches the original FLOW.
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*
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* If L7 is specified, draws the L7 payload data from it, otherwise defaults to
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* 64 bytes of payload. */
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static void
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ofctl_compose_packet(struct ovs_cmdl_context *ctx)
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{
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if (print_pcap && print_bare) {
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ovs_fatal(1, "--bare and --pcap are mutually exclusive");
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}
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if (print_pcap && isatty(STDOUT_FILENO)) {
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ovs_fatal(1, "not writing pcap data to stdout; redirect to a file "
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"or pipe to tcpdump instead");
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@@ -4989,7 +5010,7 @@ ofctl_compose_packet(struct ovs_cmdl_context *ctx)
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l7_len = dp_packet_size(&payload);
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l7 = dp_packet_steal_data(&payload);
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}
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flow_compose(&p, &flow1, l7, l7_len);
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flow_compose(&p, &flow1, l7, l7_len, bad_csum);
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free(l7);
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if (print_pcap) {
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@@ -4997,6 +5018,16 @@ ofctl_compose_packet(struct ovs_cmdl_context *ctx)
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ovs_pcap_write_header(p_file);
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ovs_pcap_write(p_file, &p);
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ovs_pcap_close(p_file);
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} else if (print_bare) {
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/* Binary to a bare hex string. */
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for (int i = 0; i < dp_packet_size(&p); i++) {
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uint8_t val = ((uint8_t *) dp_packet_data(&p))[i];
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/* Don't use ds_put_hex because it adds 0x prefix as well as
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* it doesn't guarantee an even number of payload characters, which
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* may be important elsewhere (e.g. in netdev-dummy/receive). */
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printf("%02" PRIx8, val);
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}
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} else {
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ovs_hex_dump(stdout, dp_packet_data(&p), dp_packet_size(&p), 0, false);
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}
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