On 5/13/24 12:44 PM, Eelco Chaudron wrote:
On 13 May 2024, at 9:01, Adrian Moreno wrote:On 5/10/24 12:06 PM, Eelco Chaudron wrote:On 24 Apr 2024, at 21:53, Adrian Moreno wrote:This simple program reads from psample and prints the packets to stdout. It's useful for quickly collecting sampled packets.See some comments below, did not review the actual sample application in detail. //EelcoSigned-off-by: Adrian Moreno <amore...@redhat.com> --- Documentation/automake.mk | 1 + Documentation/conf.py | 2 + Documentation/ref/index.rst | 1 + Documentation/ref/ovs-psample.8.rst | 47 ++++ include/linux/automake.mk | 1 + include/linux/psample.h | 64 ++++++ rhel/openvswitch-fedora.spec.in | 2 + rhel/openvswitch.spec.in | 1 + utilities/automake.mk | 9 + utilities/ovs-psample.c | 330 ++++++++++++++++++++++++++++ 10 files changed, 458 insertions(+) create mode 100644 Documentation/ref/ovs-psample.8.rst create mode 100644 include/linux/psample.h create mode 100644 utilities/ovs-psample.c diff --git a/Documentation/automake.mk b/Documentation/automake.mk index 47d2e336a..c22facfd6 100644 --- a/Documentation/automake.mk +++ b/Documentation/automake.mk @@ -165,6 +165,7 @@ RST_MANPAGES = \ ovs-l3ping.8.rst \ ovs-parse-backtrace.8.rst \ ovs-pki.8.rst \ + ovs-psample.8.rst \ ovs-tcpdump.8.rst \ ovs-tcpundump.1.rst \ ovs-test.8.rst \ diff --git a/Documentation/conf.py b/Documentation/conf.py index 15785605a..75efed2fc 100644 --- a/Documentation/conf.py +++ b/Documentation/conf.py @@ -134,6 +134,8 @@ _man_pages = [ u'convert "tcpdump -xx" output to hex strings'), ('ovs-test.8', u'Check Linux drivers for performance, vlan and L3 tunneling problems'), + ('ovs-psample.8', + u'Print packets sampled by psample'), ('ovs-vlan-test.8', u'Check Linux drivers for problems with vlan traffic'), ('ovsdb-server.7', diff --git a/Documentation/ref/index.rst b/Documentation/ref/index.rst index 03ada932f..d1076435a 100644 --- a/Documentation/ref/index.rst +++ b/Documentation/ref/index.rst @@ -46,6 +46,7 @@ time: ovs-pki.8 ovs-sim.1 ovs-parse-backtrace.8 + ovs-psample.8 ovs-tcpdump.8 ovs-tcpundump.1 ovs-test.8 diff --git a/Documentation/ref/ovs-psample.8.rst b/Documentation/ref/ovs-psample.8.rst new file mode 100644 index 000000000..c849c83d8 --- /dev/null +++ b/Documentation/ref/ovs-psample.8.rst @@ -0,0 +1,47 @@ +========== +ovs-sampleInteresting, here you call it all ovs-sample here, which is like ;)Yes, at the begining I called it ovs-sample as I thought to make some generic tool, but since it ended up being very psample-specific I added the "p" (and missed this one).You could add options like —local-kernel --local-userspace (--ipfix, --sflow) and it will eventually work on each datapath.You mean implementing an IPFIX and sFlow collector??If you want to keep this a separate psample utility, I would not have ovs in the name, as it's rather general and not OVS specific. Maybe just psample/psample_mon, as we also have nlmon.Well, the way the cookie is decoded into observation_domain_id and observation_point_id is ovs-specific. In fact, for the next iteration of the series I will remove the filtering API since its getting removed from the kernel series as well and add some kind of BPF code that does the filtering. Also I was considering looking into the OVSDB to ensure that we filter on groups configured in it or else we could wrongly interpet a sampled packet that comes from some other subsystem.I would prefer to have this as an ova-sample application, which can be extended with other sample methods as we see fit. So when we added userspace support we can add it here. If we find someone crazy enough to do a simple IPFIX and/or sFlow collector it can be added too. So my request would be to remove the (p) from ovs-psample, and have a switch to select --psample (the only supported (MANDATORY) option for now).
Oh, ok. Now I undestand, thank you. We want to leave room for the userspace implementation. Will do.
+========== + +Synopsis +======== + +``ovs-sample`` +[``--group=``<group> | ``-g`` <group>] + +``ovs-sample --help`` + +``ovs-sample --version`` + +Description +=========== + +Open vSwitch per-flow sampling can be configured to emit the samples +through the ``psample`` netlink multicast group. + +Such sampled traffic contains, apart from the packet, some metadata that +gives further information about the packet sample. More specifically, OVS +inserts the ``observation_domain_id`` and the ``observation_point_id`` that +where provided in the sample action (see ``ovs-actions(7)``). + +the ``ovs-sample`` program provides a simple way of joining the psample +multicast group and printing the sampled packets. + + +Options +======= + +.. option:: ``-g`` <group> or ``--group`` <group> + + Tells ``ovs-sample`` to filter out samples that don't belong to that group. + + Different ``Flow_Sample_Collector_Set`` entries can be configured with + different ``group_id`` values (see ``ovs-vswitchd.conf.db(5)``). This option + helps focusing the output on the relevant samples. + +.. option:: -h, --help + + Prints a brief help message to the console. + +.. option:: -V, --version + + Prints version information to the console. diff --git a/include/linux/automake.mk b/include/linux/automake.mk index cdae5eedc..ac306b53c 100644 --- a/include/linux/automake.mk +++ b/include/linux/automake.mk @@ -3,6 +3,7 @@ noinst_HEADERS += \ include/linux/netfilter/nf_conntrack_sctp.h \ include/linux/openvswitch.h \ include/linux/pkt_cls.h \ + include/linux/psample.h \ include/linux/gen_stats.h \ include/linux/tc_act/tc_mpls.h \ include/linux/tc_act/tc_pedit.h \ diff --git a/include/linux/psample.h b/include/linux/psample.h new file mode 100644 index 000000000..eb642f875 --- /dev/null +++ b/include/linux/psample.h @@ -0,0 +1,64 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef __LINUX_PSAMPLE_H +#define __LINUX_PSAMPLE_H + +enum { + PSAMPLE_ATTR_IIFINDEX, + PSAMPLE_ATTR_OIFINDEX, + PSAMPLE_ATTR_ORIGSIZE, + PSAMPLE_ATTR_SAMPLE_GROUP, + PSAMPLE_ATTR_GROUP_SEQ, + PSAMPLE_ATTR_SAMPLE_RATE, + PSAMPLE_ATTR_DATA, + PSAMPLE_ATTR_GROUP_REFCOUNT, + PSAMPLE_ATTR_TUNNEL, + + PSAMPLE_ATTR_PAD, + PSAMPLE_ATTR_OUT_TC, /* u16 */ + PSAMPLE_ATTR_OUT_TC_OCC, /* u64, bytes */ + PSAMPLE_ATTR_LATENCY, /* u64, nanoseconds */ + PSAMPLE_ATTR_TIMESTAMP, /* u64, nanoseconds */ + PSAMPLE_ATTR_PROTO, /* u16 */ + PSAMPLE_ATTR_USER_COOKIE, + + __PSAMPLE_ATTR_MAX +}; + +enum psample_command { + PSAMPLE_CMD_SAMPLE, + PSAMPLE_CMD_GET_GROUP, + PSAMPLE_CMD_NEW_GROUP, + PSAMPLE_CMD_DEL_GROUP, + PSAMPLE_CMD_SAMPLE_FILTER_SET, +}; + +enum psample_tunnel_key_attr { + PSAMPLE_TUNNEL_KEY_ATTR_ID, /* be64 Tunnel ID */ + PSAMPLE_TUNNEL_KEY_ATTR_IPV4_SRC, /* be32 src IP address. */ + PSAMPLE_TUNNEL_KEY_ATTR_IPV4_DST, /* be32 dst IP address. */ + PSAMPLE_TUNNEL_KEY_ATTR_TOS, /* u8 Tunnel IP ToS. */ + PSAMPLE_TUNNEL_KEY_ATTR_TTL, /* u8 Tunnel IP TTL. */ + PSAMPLE_TUNNEL_KEY_ATTR_DONT_FRAGMENT, /* No argument, set DF. */ + PSAMPLE_TUNNEL_KEY_ATTR_CSUM, /* No argument. CSUM packet. */ + PSAMPLE_TUNNEL_KEY_ATTR_OAM, /* No argument. OAM frame. */ + PSAMPLE_TUNNEL_KEY_ATTR_GENEVE_OPTS, /* Array of Geneve options. */ + PSAMPLE_TUNNEL_KEY_ATTR_TP_SRC, /* be16 src Transport Port. */ + PSAMPLE_TUNNEL_KEY_ATTR_TP_DST, /* be16 dst Transport Port. */ + PSAMPLE_TUNNEL_KEY_ATTR_VXLAN_OPTS, /* Nested VXLAN opts* */ + PSAMPLE_TUNNEL_KEY_ATTR_IPV6_SRC, /* struct in6_addr src IPv6 address. */ + PSAMPLE_TUNNEL_KEY_ATTR_IPV6_DST, /* struct in6_addr dst IPv6 address. */ + PSAMPLE_TUNNEL_KEY_ATTR_PAD, + PSAMPLE_TUNNEL_KEY_ATTR_ERSPAN_OPTS, /* struct erspan_metadata */ + PSAMPLE_TUNNEL_KEY_ATTR_IPV4_INFO_BRIDGE, /* No argument. IPV4_INFO_BRIDGE mode.*/ + __PSAMPLE_TUNNEL_KEY_ATTR_MAX +}; + +/* Can be overridden at runtime by module option */ +#define PSAMPLE_ATTR_MAX (__PSAMPLE_ATTR_MAX - 1) + +#define PSAMPLE_NL_MCGRP_CONFIG_NAME "config" +#define PSAMPLE_NL_MCGRP_SAMPLE_NAME "packets" +#define PSAMPLE_GENL_NAME "psample" +#define PSAMPLE_GENL_VERSION 1 + +#endif diff --git a/rhel/openvswitch-fedora.spec.in b/rhel/openvswitch-fedora.spec.in index 94b6d7431..9ee66180c 100644 --- a/rhel/openvswitch-fedora.spec.in +++ b/rhel/openvswitch-fedora.spec.in @@ -471,6 +471,7 @@ fi %{_bindir}/ovs-dpctl %{_bindir}/ovs-dpctl-top %{_bindir}/ovs-ofctl +%{_bindir}/ovs-psample %{_bindir}/ovs-vsctl %{_bindir}/ovsdb-client %{_bindir}/ovsdb-tool @@ -502,6 +503,7 @@ fi %{_mandir}/man8/ovs-kmod-ctl.8* %{_mandir}/man8/ovs-ofctl.8* %{_mandir}/man8/ovs-pki.8* +%{_mandir}/man8/ovs-psample.8* %{_mandir}/man8/ovs-vsctl.8* %{_mandir}/man8/ovs-vswitchd.8* %{_mandir}/man8/ovs-parse-backtrace.8* diff --git a/rhel/openvswitch.spec.in b/rhel/openvswitch.spec.in index 9903dd10a..06d79b921 100644 --- a/rhel/openvswitch.spec.in +++ b/rhel/openvswitch.spec.in @@ -195,6 +195,7 @@ exit 0 /usr/bin/ovs-pki /usr/bin/ovs-tcpdump /usr/bin/ovs-tcpundump +/usr/bin/ovs-sample /usr/bin/ovs-vlan-test /usr/bin/ovs-vsctl /usr/bin/ovsdb-client diff --git a/utilities/automake.mk b/utilities/automake.mk index 146b8c37f..0d07ff868 100644 --- a/utilities/automake.mk +++ b/utilities/automake.mk @@ -4,6 +4,7 @@ bin_PROGRAMS += \ utilities/ovs-dpctl \ utilities/ovs-ofctl \ utilities/ovs-vsctl +Guess this was added by accident.bin_SCRIPTS += utilities/ovs-docker \ utilities/ovs-pki \ utilities/ovs-pcap \ @@ -132,6 +133,14 @@ utilities_ovs_ofctl_LDADD = \ ofproto/libofproto.la \ lib/libopenvswitch.la +if LINUX +bin_PROGRAMS += utilities/ovs-psample +utilities_ovs_psample_SOURCES = utilities/ovs-psample.c +utilities_ovs_psample_LDADD = \ + ofproto/libofproto.la \ + lib/libopenvswitch.la +endif + utilities_ovs_vsctl_SOURCES = utilities/ovs-vsctl.c utilities_ovs_vsctl_LDADD = lib/libopenvswitch.la diff --git a/utilities/ovs-psample.c b/utilities/ovs-psample.c new file mode 100644 index 000000000..9127d065c --- /dev/null +++ b/utilities/ovs-psample.c @@ -0,0 +1,330 @@ +/* + * Copyright (c) 2024 Red Hat, Inc. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at: + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include <config.h> + +#include <errno.h> +#include <getopt.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> + +#include <linux/psample.h> + +#include "command-line.h" +#include "dp-packet.h" +#include "util.h" +#include "netlink.h" +#include "netlink-socket.h" +#include "openvswitch/ofp-actions.h" +#include "openvswitch/ofp-print.h" +#include "openvswitch/types.h" +#include "openvswitch/uuid.h" +#include "openvswitch/vlog.h" + +VLOG_DEFINE_THIS_MODULE(ovs_sample); + +/* -g, --group: Group id filter option */ +static uint32_t group_id = 0; +static bool has_filter; + +static int psample_family = 0; + +OVS_NO_RETURN static void usage(void) +{ + printf("%s: OpenvSwitch psample viewer\n" +"usage: %s [OPTIONS]\n" +"\nOptions:\n" +" -h, --help display this help message\n" +" -t, --group=GROUP only display events from GROUP group_id\n" +" -V, --version display %s version information\n", + program_name, program_name, program_name); + exit(EXIT_SUCCESS); +} + +struct sample; +static inline void sample_clear(struct sample *sample); +static int parse_psample(struct ofpbuf *, struct sample *sample); +static void psample_set_filter(struct nl_sock *sock); +static void parse_options(int argc, char *argv[]); +static int connect_psample_socket(struct nl_sock **sock); +static void run(struct nl_sock *sock); + +int +main(int argc OVS_UNUSED, char *argv[] OVS_UNUSED) +{ + struct nl_sock *sock; + int error; + + parse_options(argc, argv); + + error = connect_psample_socket(&sock); + if (error) { + return error; + } + + run(sock); +} + +static void parse_options(int argc, char *argv[]) +{ + static const struct option long_options[] = { + {"group", required_argument, NULL, 'g'}, + {"help", no_argument, NULL, 'h'}, + {"version", no_argument, NULL, 'V'}, + {NULL, 0, NULL, 0}, + }; + + char *short_options_ = + ovs_cmdl_long_options_to_short_options(long_options); + char *short_options = xasprintf("+%s", short_options_);Why not move the definition to a separate line to avoid the odd line wrapping (and maybe free early);Sure.static const struct option long_options[] = { {"group", required_argument, NULL, 'g'}, {"help", no_argument, NULL, 'h'}, {"version", no_argument, NULL, 'V'}, {NULL, 0, NULL, 0}, }; char *tmp_short_options, *short_options; tmp_short_options = ovs_cmdl_long_options_to_short_options(long_options); short_options = xasprintf("+%s", tmp_short_options); free(tmp_short_options);+ for (;;) { + int option; + + option = getopt_long(argc, argv, short_options, long_options, NULL); + if (option == -1) { + break; + }New line?Ack.+ switch (option) { + case 'g': + {If we do this we would have the { right after the case statement and do it for all branches. For example: switch (action->type) { case TC_ACT_VLAN_POP: { nl_msg_put_flag(buf, OVS_ACTION_ATTR_POP_VLAN); } break; case TC_ACT_VLAN_PUSH: { struct ovs_action_push_vlan *push; push = nl_msg_put_unspec_zero(buf, OVS_ACTION_ATTR_PUSH_VLAN, sizeof *push); push->vlan_tpid = action->vlan.vlan_push_tpid; push->vlan_tci = htons(action->vlan.vlan_push_id | (action->vlan.vlan_push_prio << 13) | VLAN_CFI); } break;+ char *endptr; + + if (has_filter) { + ovs_fatal(0, "-g or --group may be specified only once"); + } + + group_id = strtol(optarg, &endptr, 10); + if (endptr - optarg != strlen(optarg)) { + ovs_fatal(0, "-g or --group expects a valid decimal" + " 32-bit number"); + } + + has_filter = true; + } + break; + case 'h': + usage(); + break; + + case 'V': + ovs_print_version(0, 0);In theory, we are not cleaning up the memory ;)I guess so. I'll free it up anyway.+ exit(EXIT_SUCCESS); + + case '?': + exit(EXIT_FAILURE); + + default: + OVS_NOT_REACHED(); + } + } + free(short_options_); + free(short_options); +} + +static int connect_psample_socket(struct nl_sock **sock) +{ + unsigned int psample_packet_mcgroup; + int error; + + error = nl_lookup_genl_family(PSAMPLE_GENL_NAME , &psample_family); + if (error) { + VLOG_ERR("PSAMPLE_GENL_NAME not found: %i", error);Should we exit?Yep, probably.+ } + + error = nl_lookup_genl_mcgroup(PSAMPLE_GENL_NAME, + PSAMPLE_NL_MCGRP_SAMPLE_NAME, + &psample_packet_mcgroup); + if (error) { + VLOG_ERR("psample packet multicast group not found: %i", error); + return error; + } + + error = nl_sock_create(NETLINK_GENERIC, sock); + if (error) { + VLOG_ERR("cannot create netlink socket: %i ", error); + return error; + } + + nl_sock_listen_all_nsid(*sock, true); + + psample_set_filter(*sock); + + error = nl_sock_join_mcgroup(*sock, psample_packet_mcgroup); + if (error) { + nl_sock_destroy(*sock); + *sock = NULL; + VLOG_ERR("cannot join psample multicast group: %i", error); + return error; + } + return 0; +} + +/* Internal representation of a sample. */ +struct sample { + struct dp_packet packet; + uint32_t group_id; + uint32_t obs_domain_id; + uint32_t obs_point_id; + bool has_cookie; +}; + +static inline void +sample_clear(struct sample *sample) { + sample->group_id = 0; + sample->obs_domain_id = 0; + sample->obs_point_id = 0; + sample->has_cookie = false; + dp_packet_clear(&sample->packet); +} + +static int +parse_psample(struct ofpbuf *buf, struct sample *sample) { + static const struct nl_policy psample_packet_policy[] = { + [PSAMPLE_ATTR_SAMPLE_GROUP] = { .type = NL_A_U32 }, + [PSAMPLE_ATTR_DATA] = { .type = NL_A_UNSPEC, + .optional = true, }, + [PSAMPLE_ATTR_USER_COOKIE] = { .type = NL_A_UNSPEC, + .optional = true }, + }; + + struct ofpbuf b = ofpbuf_const_initializer(buf->data, buf->size); + struct nlmsghdr *nlmsg = ofpbuf_try_pull(&b, sizeof *nlmsg); + struct genlmsghdr *genl = ofpbuf_try_pull(&b, sizeof *genl); + struct nlattr *attr; + const char *cookie; + + struct nlattr *a[ARRAY_SIZE(psample_packet_policy)]; + if (!nlmsg || !genl + || !nl_policy_parse(&b, 0, psample_packet_policy, a, + ARRAY_SIZE(psample_packet_policy))) { + return EINVAL; + } + + attr = a[PSAMPLE_ATTR_DATA]; + if (attr) { + dp_packet_push(&sample->packet, nl_attr_get(attr), + nl_attr_get_size(attr)); + } + + sample->group_id = nl_attr_get_u32(a[PSAMPLE_ATTR_SAMPLE_GROUP]); + + attr = a[PSAMPLE_ATTR_USER_COOKIE]; + if (attr && nl_attr_get_size(attr) == 8) { + cookie = nl_attr_get(attr); + sample->has_cookie = true; + sample->obs_domain_id = (uint32_t) *(&cookie[0]); + sample->obs_point_id = (uint32_t) *(&cookie[4]); + } + return 0; +} + +static int _psample_set_filter(struct nl_sock *sock, uint32_t group, + bool valid) +{ + uint64_t stub[512 / 8]; + struct ofpbuf buf; + int error; + + ofpbuf_use_stub(&buf, stub, sizeof stub); + + nl_msg_put_genlmsghdr(&buf, 0, psample_family, NLM_F_REQUEST, + PSAMPLE_CMD_SAMPLE_FILTER_SET, 1); + if (valid) { + nl_msg_put_u32(&buf, PSAMPLE_ATTR_SAMPLE_GROUP, group); + } + + error = nl_sock_send(sock, &buf, false); + if (error) { + return error; + } + + ofpbuf_clear(&buf); + error = nl_sock_recv(sock, &buf, NULL, false); + if (!error) { + struct nlmsghdr *h = ofpbuf_at(&buf, 0, NLMSG_HDRLEN);New line?+ if (h->nlmsg_type == NLMSG_ERROR) { + const struct nlmsgerr *e; + e = ofpbuf_at(&buf, NLMSG_HDRLEN, + NLMSG_ALIGN(sizeof(struct nlmsgerr))); + if (!e)Use {} even for single line.When I spend a bit of time with the kernel my mind plays tricks on me :-)+ return EINVAL; + if (e && e->error < 0) + return -e->error; + } + } else if (error != EAGAIN) { + return error; + } + return 0; +} + +static void psample_set_filter(struct nl_sock *sock) +{ + int error;New line?+ if (has_filter) { + error = _psample_set_filter(sock, group_id, true); + if (error) { + VLOG_WARN("Failed to install in-kernel filter (%s). " + "Falling back to userspace filtering.", + ovs_strerror(error)); + } + } +} + +static void run(struct nl_sock *sock) +{ + static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 10); + int error; + + struct sample sample = {};Move this up above the error definition.Ack.+ dp_packet_init(&sample.packet, 1500); + + for (;;) { + uint64_t buf_stub[4096 / 8]; + struct ofpbuf buf; + + sample_clear(&sample); + + ofpbuf_use_stub(&buf, buf_stub, sizeof buf_stub); + error = nl_sock_recv(sock, &buf, NULL, true); + + if (error == ENOBUFS) { + fprintf(stderr, "[missed events]\n"); + continue; + } else if (error == EAGAIN) { + continue; + } else if (error) { + VLOG_ERR_RL(&rl, "error reading samples: %i", error); + } + + error = parse_psample(&buf, &sample); + if (error) + VLOG_ERR_RL(&rl, "error parsing samples: %i", error); + + if (!has_filter || sample.group_id == group_id) { + fprintf(stdout, "group_id=0x%"PRIx32" ", + sample.group_id); + if (sample.has_cookie) { + fprintf(stdout, + "obs_domain=0x%"PRIx32",obs_point=0x%"PRIx32" ", + sample.obs_domain_id, sample.obs_point_id); + } + ofp_print_dp_packet(stdout, &sample.packet); + } + } +} + -- 2.44.0
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