| Message ID | 20240305154442.2437461-2-aconole@redhat.com |
|---|---|
| State | Accepted |
| Commit | 86b9e653ef226985b0fef1be7c03d8be305fa0b7 |
| Headers | show |
| Series | debugging: Add a revalidator probe, and monitor script | expand |
| Context | Check | Description |
|---|---|---|
| ovsrobot/apply-robot | success | apply and check: success |
| ovsrobot/github-robot-_Build_and_Test | success | github build: passed |
| ovsrobot/intel-ovs-compilation | success | test: success |
On 5 Mar 2024, at 16:44, Aaron Conole wrote: > From: Kevin Sprague <ksprague0711@gmail.com> > > During normal operations, it is useful to understand when a particular flow > gets removed from the system. This can be useful when debugging performance > issues tied to ofproto flow changes, trying to determine deployed traffic > patterns, or while debugging dynamic systems where ports come and go. > > Prior to this change, there was a lack of visibility around flow expiration. > The existing debugging infrastructure could tell us when a flow was added to > the datapath, but not when it was removed or why. > > This change introduces a USDT probe at the point where the revalidator > determines that the flow should be removed. Additionally, we track the > reason for the flow eviction and provide that information as well. With > this change, we can track the complete flow lifecycle for the netlink > datapath by hooking the upcall tracepoint in kernel, the flow put USDT, and > the revalidator USDT, letting us watch as flows are added and removed from > the kernel datapath. > > This change only enables this information via USDT probe, so it won't be > possible to access this information any other way (see: > Documentation/topics/usdt-probes.rst). > > Also included is a script (utilities/usdt-scripts/flow_reval_monitor.py) > which serves as a demonstration of how the new USDT probe might be used > going forward. > > Acked-by: Han Zhou <hzhou@ovn.org> > Signed-off-by: Kevin Sprague <ksprague0711@gmail.com> > Co-authored-by: Aaron Conole <aconole@redhat.com> > Signed-off-by: Aaron Conole <aconole@redhat.com> Thanks Aaron for following this up. One small nit, but none blocking, maybe can fix it on commit. Acked-by: Eelco Chaudron <echaudro@redhat.com> > --- > v8 -> v9: Reorganized the flow delete reasons enum > Updated flow_reval_monitor to use pahole to extract fields > Added the purge reason with a proper USDT point > Updated documentation > Dropped all the outstanding ACKs > > v9 -> v10: Reorder the usdt arguments > Rewrite delete comment > Added python docstrings to functions > Use ternary assignment > Clean up example output comment > Capitolize 'F' in Flow > Snip out the comments including help text > Shrink try / except blocks for the USDT probes > refactor the print()/sys.exit() into a single call that uses > sys.stderr > Re-run black & flake8 > > > Documentation/topics/usdt-probes.rst | 43 + > ofproto/ofproto-dpif-upcall.c | 44 +- > utilities/automake.mk | 3 + > utilities/usdt-scripts/flow_reval_monitor.py | 978 +++++++++++++++++++ > 4 files changed, 1062 insertions(+), 6 deletions(-) > create mode 100755 utilities/usdt-scripts/flow_reval_monitor.py > > diff --git a/Documentation/topics/usdt-probes.rst b/Documentation/topics/usdt-probes.rst > index e527f43bab..b9a6c54b29 100644 > --- a/Documentation/topics/usdt-probes.rst > +++ b/Documentation/topics/usdt-probes.rst > @@ -214,8 +214,10 @@ Available probes in ``ovs_vswitchd``: > - dpif_recv:recv_upcall > - main:poll_block > - main:run_start > +- revalidate:flow_result > - revalidate_ukey\_\_:entry > - revalidate_ukey\_\_:exit > +- revalidator_sweep\_\_:flow_result > - udpif_revalidator:start_dump > - udpif_revalidator:sweep_done > > @@ -443,6 +445,47 @@ sweep phase was completed. > - ``utilities/usdt-scripts/reval_monitor.py`` > > > +probe revalidate:flow_result > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > + > +**Description**: > +This probe is triggered when the revalidator has executed on a particular > +flow key to make a determination whether to evict a flow, and the cause > +for eviction. The revalidator runs periodically, and this probe will only > +be triggered when a flow is flagged for revalidation. > + > +**Arguments**: > + > +- *arg0*: ``(struct udpif *) udpif`` > +- *arg1*: ``(struct udpif_key *) ukey`` > +- *arg2*: ``(enum reval_result) result`` > +- *arg3*: ``(enum flow_del_reason) del_reason`` > + > +**Script references**: > + > +- ``utilities/usdt-scripts/flow_reval_monitor.py`` > + > + > +probe revalidator_sweep\_\_:flow_result > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > + > +**Description**: > +This probe is placed in the path of the revalidator sweep, and is executed > +under the condition that a flow entry is in an unexpected state, or the > +flows were asked to be purged due to a user action. > + > +**Arguments**: > + > +- *arg0*: ``(struct udpif *) udpif`` > +- *arg1*: ``(struct udpif_key *) ukey`` > +- *arg2*: ``(enum reval_result) result`` > +- *arg3*: ``(enum flow_del_reason) del_reason`` > + > +**Script references**: > + > +- ``utilities/usdt-scripts/flow_reval_monitor.py`` > + > + > Adding your own probes > ---------------------- > > diff --git a/ofproto/ofproto-dpif-upcall.c b/ofproto/ofproto-dpif-upcall.c > index 9a5c5c29ce..d881956366 100644 > --- a/ofproto/ofproto-dpif-upcall.c > +++ b/ofproto/ofproto-dpif-upcall.c > @@ -269,6 +269,20 @@ enum ukey_state { > }; > #define N_UKEY_STATES (UKEY_DELETED + 1) > > +enum flow_del_reason { > + FDR_NONE = 0, /* No deletion reason for the flow. */ > + FDR_AVOID_CACHING, /* Flow deleted to avoid caching. */ > + FDR_BAD_ODP_FIT, /* The flow had a bad ODP flow fit. */ > + FDR_FLOW_IDLE, /* The flow went unused and was deleted. */ > + FDR_FLOW_LIMIT, /* All flows being killed. */ > + FDR_FLOW_WILDCARDED, /* The flow needed a narrower wildcard mask. */ > + FDR_NO_OFPROTO, /* The flow didn't have an associated ofproto. */ > + FDR_PURGE, /* User action caused flows to be killed. */ > + FDR_TOO_EXPENSIVE, /* The flow was too expensive to revalidate. */ > + FDR_UPDATE_FAIL, /* Flow state transition was unexpected. */ > + FDR_XLATION_ERROR, /* There was an error translating the flow. */ > +}; > + > /* 'udpif_key's are responsible for tracking the little bit of state udpif > * needs to do flow expiration which can't be pulled directly from the > * datapath. They may be created by any handler or revalidator thread at any > @@ -2279,7 +2293,8 @@ populate_xcache(struct udpif *udpif, struct udpif_key *ukey, > static enum reval_result > revalidate_ukey__(struct udpif *udpif, const struct udpif_key *ukey, > uint16_t tcp_flags, struct ofpbuf *odp_actions, > - struct recirc_refs *recircs, struct xlate_cache *xcache) > + struct recirc_refs *recircs, struct xlate_cache *xcache, > + enum flow_del_reason *del_reason) > { > struct xlate_out *xoutp; > struct netflow *netflow; > @@ -2300,11 +2315,13 @@ revalidate_ukey__(struct udpif *udpif, const struct udpif_key *ukey, > netflow = NULL; > > if (xlate_ukey(udpif, ukey, tcp_flags, &ctx)) { > + *del_reason = FDR_XLATION_ERROR; > goto exit; > } > xoutp = &ctx.xout; > > if (xoutp->avoid_caching) { > + *del_reason = FDR_AVOID_CACHING; > goto exit; > } > > @@ -2318,6 +2335,7 @@ revalidate_ukey__(struct udpif *udpif, const struct udpif_key *ukey, > ofpbuf_clear(odp_actions); > > if (!ofproto) { > + *del_reason = FDR_NO_OFPROTO; > goto exit; > } > > @@ -2329,6 +2347,7 @@ revalidate_ukey__(struct udpif *udpif, const struct udpif_key *ukey, > if (odp_flow_key_to_mask(ukey->mask, ukey->mask_len, &dp_mask, &ctx.flow, > NULL) > == ODP_FIT_ERROR) { > + *del_reason = FDR_BAD_ODP_FIT; > goto exit; > } > > @@ -2338,6 +2357,7 @@ revalidate_ukey__(struct udpif *udpif, const struct udpif_key *ukey, > * down. Note that we do not know if the datapath has ignored any of the > * wildcarded bits, so we may be overly conservative here. */ > if (flow_wildcards_has_extra(&dp_mask, ctx.wc)) { > + *del_reason = FDR_FLOW_WILDCARDED; > goto exit; > } > > @@ -2407,7 +2427,7 @@ static enum reval_result > revalidate_ukey(struct udpif *udpif, struct udpif_key *ukey, > const struct dpif_flow_stats *stats, > struct ofpbuf *odp_actions, uint64_t reval_seq, > - struct recirc_refs *recircs) > + struct recirc_refs *recircs, enum flow_del_reason *del_reason) > OVS_REQUIRES(ukey->mutex) > { > bool need_revalidate = ukey->reval_seq != reval_seq; > @@ -2437,8 +2457,12 @@ revalidate_ukey(struct udpif *udpif, struct udpif_key *ukey, > xlate_cache_clear(ukey->xcache); > } > result = revalidate_ukey__(udpif, ukey, push.tcp_flags, > - odp_actions, recircs, ukey->xcache); > - } /* else delete; too expensive to revalidate */ > + odp_actions, recircs, ukey->xcache, > + del_reason); > + } else { > + /* Delete, since it is too expensive to revalidate. */ > + *del_reason = FDR_TOO_EXPENSIVE; > + } > } else if (!push.n_packets || ukey->xcache > || !populate_xcache(udpif, ukey, push.tcp_flags)) { > result = UKEY_KEEP; > @@ -2838,6 +2862,7 @@ revalidate(struct revalidator *revalidator) > for (f = flows; f < &flows[n_dumped]; f++) { > long long int used = f->stats.used; > struct recirc_refs recircs = RECIRC_REFS_EMPTY_INITIALIZER; > + enum flow_del_reason del_reason = FDR_NONE; > struct dpif_flow_stats stats = f->stats; > enum reval_result result; > struct udpif_key *ukey; > @@ -2912,9 +2937,10 @@ revalidate(struct revalidator *revalidator) > } > if (kill_them_all || (used && used < now - max_idle)) { > result = UKEY_DELETE; > + del_reason = (kill_them_all) ? FDR_FLOW_LIMIT : FDR_FLOW_IDLE; > } else { > result = revalidate_ukey(udpif, ukey, &stats, &odp_actions, > - reval_seq, &recircs); > + reval_seq, &recircs, &del_reason); > } > ukey->dump_seq = dump_seq; > > @@ -2923,6 +2949,8 @@ revalidate(struct revalidator *revalidator) > udpif_update_flow_pps(udpif, ukey, f); > } > > + OVS_USDT_PROBE(revalidate, flow_result, udpif, ukey, result, > + del_reason); > if (result != UKEY_KEEP) { > /* Takes ownership of 'recircs'. */ > reval_op_init(&ops[n_ops++], result, udpif, ukey, &recircs, > @@ -2975,6 +3003,7 @@ revalidator_sweep__(struct revalidator *revalidator, bool purge) > size_t n_ops = 0; > > CMAP_FOR_EACH(ukey, cmap_node, &umap->cmap) { > + enum flow_del_reason del_reason = FDR_NONE; > enum ukey_state ukey_state; > > /* Handler threads could be holding a ukey lock while it installs a > @@ -2993,6 +3022,7 @@ revalidator_sweep__(struct revalidator *revalidator, bool purge) > > if (purge || ukey_state == UKEY_INCONSISTENT) { > result = UKEY_DELETE; > + del_reason = purge ? FDR_PURGE : FDR_UPDATE_FAIL; > } else if (!seq_mismatch) { > result = UKEY_KEEP; > } else { > @@ -3000,13 +3030,15 @@ revalidator_sweep__(struct revalidator *revalidator, bool purge) > COVERAGE_INC(revalidate_missed_dp_flow); > memcpy(&stats, &ukey->stats, sizeof stats); > result = revalidate_ukey(udpif, ukey, &stats, &odp_actions, > - reval_seq, &recircs); > + reval_seq, &recircs, &del_reason); > } > if (result != UKEY_KEEP) { > /* Clears 'recircs' if filled by revalidate_ukey(). */ > reval_op_init(&ops[n_ops++], result, udpif, ukey, &recircs, > &odp_actions); > } > + OVS_USDT_PROBE(revalidator_sweep__, flow_sweep_result, udpif, > + ukey, result, del_reason); > } > ovs_mutex_unlock(&ukey->mutex); > > diff --git a/utilities/automake.mk b/utilities/automake.mk > index 9a2114df40..146b8c37fb 100644 > --- a/utilities/automake.mk > +++ b/utilities/automake.mk > @@ -23,6 +23,7 @@ scripts_DATA += utilities/ovs-lib > usdt_SCRIPTS += \ > utilities/usdt-scripts/bridge_loop.bt \ > utilities/usdt-scripts/dpif_nl_exec_monitor.py \ > + utilities/usdt-scripts/flow_reval_monitor.py \ > utilities/usdt-scripts/kernel_delay.py \ > utilities/usdt-scripts/kernel_delay.rst \ > utilities/usdt-scripts/reval_monitor.py \ > @@ -72,6 +73,7 @@ EXTRA_DIST += \ > utilities/docker/debian/build-kernel-modules.sh \ > utilities/usdt-scripts/bridge_loop.bt \ > utilities/usdt-scripts/dpif_nl_exec_monitor.py \ > + utilities/usdt-scripts/flow_reval_monitor.py \ > utilities/usdt-scripts/kernel_delay.py \ > utilities/usdt-scripts/kernel_delay.rst \ > utilities/usdt-scripts/reval_monitor.py \ > @@ -146,6 +148,7 @@ FLAKE8_PYFILES += utilities/ovs-pcap.in \ > utilities/ovs-tcpdump.in \ > utilities/ovs-pipegen.py \ > utilities/usdt-scripts/dpif_nl_exec_monitor.py \ > + utilities/usdt-scripts/flow_reval_monitor.py \ > utilities/usdt-scripts/upcall_monitor.py \ > utilities/usdt-scripts/upcall_cost.py > > diff --git a/utilities/usdt-scripts/flow_reval_monitor.py b/utilities/usdt-scripts/flow_reval_monitor.py > new file mode 100755 > index 0000000000..dbd80b05a7 > --- /dev/null > +++ b/utilities/usdt-scripts/flow_reval_monitor.py > @@ -0,0 +1,978 @@ > +#!/usr/bin/env python3 > +# > +# Copyright (c) 2022-2024 Redhat, 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. > +# > +# Script information: > +# ------------------- > +# flow_reval_monitor.py uses the dpif_netlink_operate:flow_put and > +# revalidator:flow_result USDT probes to monitor flow lifetimes and > +# expiration events. By default, this will show all flow_put and flow > +# expiration events, along with their reasons. This will look like so: > +# > +# TID TIME UFID EVENT/REASON > +# 71828 1549.119959874 39f0f28f-33... Insert (put) flow to ovs kernel module. > +# 71828 1549.420877223 850db41c-47... Insert (put) flow to ovs kernel module. > +# 71828 1550.476923456 5bacfca9-fe... Insert (put) flow to ovs kernel module. > +# 71832 1559.650192299 850db41c-47... Idle flow timed out > +# 71832 1561.153332825 39f0f28f-33... Idle flow timed out > +# 71832 1572.684316304 5bacfca9-fe... Idle flow timed out > +# > +# Flow key data can be printed using the --flow-keys option. This will > +# print the equivalent datapath flow string. > +# > +# When filtering flows, the syntax is the same as used by > +# `ovs-appctl dpctl/add-flow`. > +# > +# For a complete list of options, please use the '--help' or '-h' argument. > +# > +# Examples: > +# > +# To use the script on a running ovs-vswitchd to see flow keys and expiration > +# events for flows with an ipv4 source of 192.168.10.10: > +# $ ./flow_reval_monitor.py --flow-keys --filter-flows \ > +# "ipv4(src=192.168.10.10)" > +# TIME UFID EVENT/REASON > +# 105082.457322742 ufid:f76fc899-376d-466b-bc74-0000b933eb97 flow_put > +# ufid:f76fc899-376d-466b-bc74-0000b933eb97 has the following flow information: > +# in_port(2), > +# eth(src=0e:04:47:fc:74:51, dst=da:dc:c5:69:05:d7), \ > +# eth_type(0x800), \ > +# ipv4(src=192.168.10.10, dst=192.168.10.30, proto=1, tos=0, ttl=64,[...]), > +# icmp(type=8, code=0) > +# 105092.635450202 ufid:f76fc899-376d-466b-bc74-0000b933eb97 Flow timed out > +# > +# Notes: > +# 1) No options are needed to attach when there is a single running instance > +# of ovs-vswitchd. > +# 2) If you're using the flow filtering option, it will only track flows that > +# have been upcalled since the script began running. > +# 3) When using the flow filtering option, the key size will likely need to > +# be expanded to match on all the fields in the message. The default is > +# kept small to keep the buffer copy sizes down when displaying > +# flows (-k), but is hardcoded to 2048 when an actual filter (-l) is > +# applied > +# 4) The flow filtering format is a simplified form of the ODP syntax, and > +# does not support masked matches, which means you will need to filter > +# on exact details. The fields present are dependent on how the > +# classifier and OFP rules form the ODP rules - not all fields may be > +# present in a particular flow. > +# 5) The flow_put filtering only happens for flows installed into the ovs > +# kernel module. This means flows taking the HW offload path (ie: tc), > +# or on DPDK side won't get matched. > + > +try: > + from bcc import BPF > + from bcc import USDT > + from bcc import USDTException > +except ModuleNotFoundError: > + print("ERROR: Can't find the BPF Compiler Collection Tools.") > + print("Please install them before running this script.") > + exit(1) > + > +from enum import IntEnum > +from ipaddress import IPv4Address, IPv6Address > +from pathlib import Path > + > +import argparse > +import psutil > +import re > +import struct > +import subprocess > +import sys > + > +# > +# eBPF source code > +# > +bpf_src = """ > +#include <linux/sched.h> > + > +#define MAX_KEY <MAX_KEY_VAL> > +#define FLOW_FILTER <FILTER_BOOL> > + > +enum probe { <EVENT_ENUM> }; > + > +<OVS_INCLUDE_DEFINITIONS> > + > +struct event_t { > + u64 ts; > + u32 pid; > + u32 result; > + u32 reason; > + u32 ufid[4]; > + u64 key_size; > + unsigned char key[MAX_KEY]; > + enum probe probe; > +}; > + > +BPF_HASH(watchlist, ovs_u128); > +BPF_RINGBUF_OUTPUT(events, <BUFFER_PAGE_COUNT>); > +BPF_TABLE("percpu_array", uint32_t, uint64_t, dropcnt, 1); > + > +/* Hack to make a 'static' like storage object. */ > +BPF_TABLE("percpu_array", uint32_t, struct udpif_key, udpk, 1); > + > +static struct event_t *get_event(enum probe p) { > + struct event_t *event = events.ringbuf_reserve(sizeof(struct event_t)); > + > + if (!event) { > + dropcnt.increment(0); > + return NULL; > + } > + > + event->probe = p; > + event->ts = bpf_ktime_get_ns(); > + event->pid = bpf_get_current_pid_tgid(); > + > + return event; > +} > + > +static int emit_flow_result(struct udpif_key *ukey, ovs_u128 ufid, > + u32 result, u32 reason) { > + struct event_t *event = NULL; > + u64 *ufid_present = NULL; > + > + ufid_present = watchlist.lookup(&ufid); > + if (FLOW_FILTER && !ufid_present) { > + return 0; > + } > + > + event = get_event(FLOW_RESULT); > + if (!event) { > + /* If we can't reserve the space in the ring buffer, return 1. */ > + return 1; > + } > + > + event->result = result; > + event->reason = reason; > + bpf_probe_read(&event->ufid, sizeof ufid, &ufid); > + events.ringbuf_submit(event, 0); > + > + return 0; > +} > + > +int usdt__flow_result(struct pt_regs *ctx) { > + struct udpif_key *ukey = NULL; > + u32 reason = 0; > + u32 result = 0; > + ovs_u128 ufid; > + u32 zero = 0; > + > + ukey = udpk.lookup(&zero); > + if (!ukey) { > + return 1; > + } > + bpf_usdt_readarg_p(2, ctx, ukey, sizeof(struct udpif_key)); > + bpf_usdt_readarg(3, ctx, &result); > + bpf_usdt_readarg(4, ctx, &reason); > + ufid = ukey->ufid; > + > + return emit_flow_result(ukey, ufid, result, reason); > +} > + > +int usdt__flow_sweep_result(struct pt_regs *ctx) { > + struct udpif_key *ukey = NULL; > + u32 reason = 0; > + u32 result = 0; > + ovs_u128 ufid; > + u32 zero = 0; > + > + ukey = udpk.lookup(&zero); > + if (!ukey) { > + return 1; > + } > + bpf_usdt_readarg_p(2, ctx, ukey, sizeof(struct udpif_key)); > + bpf_usdt_readarg(3, ctx, &result); > + bpf_usdt_readarg(4, ctx, &reason); > + ufid = ukey->ufid; > + > + return emit_flow_result(ukey, ufid, result, reason); > +} > + > +int usdt__op_flow_put(struct pt_regs *ctx) { > + struct dpif_flow_put put; > + ovs_u128 ufid; > + > + struct event_t *event = get_event(OP_FLOW_PUT); > + if (!event) { > + /* If we can't reserve the space in the ring buffer, return 1. */ > + return 1; > + } > + > + bpf_usdt_readarg_p(2, ctx, &put, sizeof put); > + bpf_probe_read(&event->ufid, sizeof event->ufid, put.ufid); > + bpf_probe_read(&ufid, sizeof ufid, &event->ufid); > + if (put.key_len > MAX_KEY) { > + put.key_len = MAX_KEY; > + } > + event->key_size = put.key_len; > + bpf_probe_read(&event->key, put.key_len, put.key); > + event->reason = 0; > + events.ringbuf_submit(event, 0); > + > + watchlist.increment(ufid); > + return 0; > +} > +""" > + > +Event = IntEnum("Event", ["OP_FLOW_PUT", "FLOW_RESULT"], start=0) > +RevalResult = IntEnum( > + "reval_result", > + [ > + "UKEY_KEEP", > + "UKEY_DELETE", > + "UKEY_MODIFY", > + ], > + start=0, > +) > +FdrReasons = IntEnum( > + "flow_del_reason", > + [ > + "FDR_NONE", > + "FDR_AVOID_CACHING", > + "FDR_BAD_ODP_FIT", > + "FDR_FLOW_IDLE", > + "FDR_FLOW_LIMIT", > + "FDR_FLOW_WILDCARDED", > + "FDR_NO_OFPROTO", > + "FDR_PURGE", > + "FDR_TOO_EXPENSIVE", > + "FDR_UPDATE_FAIL", > + "FDR_XLATION_ERROR", > + ], > + start=0, > +) > + > +FdrReasonStrings = [ > + "No deletion reason", > + "Cache avoidance flag set", > + "Bad ODP flow fit", > + "Idle flow timed out", > + "Kill all flows condition detected", > + "Mask too wide - need narrower match", > + "No matching ofproto rules", > + "Too expensive to revalidate", > + "Purged with user action", > + "Flow state inconsistent after updates", > + "Flow translation error", > +] > + > + > +def err(msg, code=-1): > + """Prints an error to stderr and exits""" > + > + print(msg, file=sys.stderr) > + sys.exit(code) > + > + > +def run_program(command): > + """Invokes a new process and returns stdout. Note that this will honor > + the PATH environment variable, so best to use it sparingly, or with a > + full path to binary.""" > + > + try: > + process = subprocess.run( > + command, > + stdout=subprocess.PIPE, > + stderr=subprocess.STDOUT, > + encoding="utf8", > + check=True, > + ) > + > + except subprocess.CalledProcessError as perror: > + return perror.returncode, perror.stdout > + > + return 0, process.stdout > + > + > +def get_ovs_definitions(objects, pahole="pahole", pid=None): > + """Uses `pahole` or similar utility to pull object definitions from a > + running OVS process. The objects argument can either be a string > + or can be a list of strings. Optionally, pass a specific `pahole` > + binary to use rather than the default. PID needs to be set.""" > + > + if pid is None: > + raise ValueError("A valid pid value should be supplied!") > + > + if not isinstance(objects, list): > + objects = [objects] > + > + if len(objects) == 0: > + raise ValueError("Must supply at least one object!") > + > + vswitchd = Path(f"/proc/{pid}/exe").resolve() > + > + object_str = ",".join(objects) > + > + def run_pahole(debug_file): > + """Helper designed for running pahole, or something with compatible > + output""" > + > + error, result = run_program( > + [pahole, "-C", object_str, "--compile", debug_file] > + ) > + > + if error: > + if f"pahole: {debug_file}: Invalid argument" not in result: > + err( > + "ERROR: Pahole failed to get ovs-vswitchd data " > + "structures!\n{}".format( > + re.sub( > + "^", " " * 7, result.rstrip(), flags=re.MULTILINE > + ) > + ) > + ) > + > + return None > + > + if bool(re.search("pahole: type .* not found", result)): > + return None > + > + return result > + > + def run_readelf(bin_file): > + """Helper designed for running readelf or something with compatible > + output""" > + > + error, result = run_program( > + ["readelf", "-n", "--debug-dump=links", bin_file] > + ) > + > + if error: > + err( > + "ERROR: Failed 'readelf' on \"{}\"!\n{}".format( > + bin_file, re.sub("^", " " * 7, result, flags=re.MULTILINE) > + ) > + ) > + > + return result > + > + def get_debug_file(bin_file): > + """Runs readelf against the binary, and attempts to find the associated > + debuginfo file.""" > + elf_result = run_readelf(bin_file) > + match = re.search("Build ID: ([0-9a-fA-F]+)", elf_result) > + if not match: > + err("ERROR: Can't find build ID to read debug symbols!") > + > + dbg_file = "/usr/lib/debug/.build-id/{}/{}.debug".format( > + match.group(1)[:2], match.group(1)[2:] > + ) > + > + return dbg_file > + > + def get_from_shared_library(debug_file): > + ovs_libs = [ > + "libofproto", > + "libopenvswitch", > + "libovsdb", > + "libsflow", > + "libvtep", > + ] > + error, ldd_result = run_program(["ldd", debug_file]) > + > + if error: > + err( > + "ERROR: Failed 'ldd' on \"{}\"!\n{}".format( > + debug_file, > + re.sub("^", " " * 7, ldd_result, flags=re.MULTILINE), > + ) > + ) > + > + for lib in ovs_libs: > + match = re.search( > + r"^\s*{}.* => (.*) \(.*\)$".format(lib), > + ldd_result, > + flags=re.MULTILINE, > + ) > + if match is None: > + continue > + > + result = run_pahole(match.group(1)) > + if result is None: > + result = run_pahole(get_debug_file(match.group(1))) > + > + if result: > + return result > + > + return None > + > + # > + # First try to find the debug data as part of the executable. > + # > + result = run_pahole(vswitchd) > + > + if result is None: > + print(f'INFO: Failed to find debug info in "{vswitchd}"!') > + > + # > + # Get additional .debug information if available. > + # > + dbg_file = get_debug_file(vswitchd) > + result = run_pahole(dbg_file) > + if result is None: > + print(f'INFO: Failed to find debug info in "{dbg_file}"!') > + > + # > + # Try to get information from shared libraries if used. > + # > + result = get_from_shared_library(vswitchd) > + > + if result is None: > + err(f"ERROR: Failed to find needed data structures through {pahole}") > + > + # > + # We need an empty _Atomic definition to avoid compiler complaints. > + # > + result = "#define _Atomic\n" + result > + > + # > + # Remove the uint64_t definition as it conflicts with the kernel one. > + # > + result = re.sub("^typedef.*uint64_t;$", "", result, flags=re.MULTILINE) > + > + return result > + > + > +def buffer_size_type(astr, min=64, max=2048): > + """Checks whether a string passed in is a number between min and max.""" > + > + value = int(astr) > + if min <= value <= max: > + return value > + else: > + raise argparse.ArgumentTypeError( > + "value not in range {}-{}".format(min, max) > + ) > + > + > +def format_ufid(ufid): > + """Formats a UFID object into a human readable form. If ufid is None, > + prints "ufid:none" instead.""" > + if ufid is None: > + return "ufid:none" > + > + return "{:08x}-{:04x}-{:04x}-{:04x}-{:04x}{:08x}".format( > + ufid[0], > + ufid[1] >> 16, > + ufid[1] & 0xFFFF, > + ufid[2] >> 16, > + ufid[2] & 0, > + ufid[3], > + ) > + > + > +def find_and_delete_from_watchlist(event): > + """If the event ufid is in the watchlist, delete it""" > + > + for k, _ in b["watchlist"].items(): > + key_ufid = struct.unpack("=IIII", k) > + if key_ufid == tuple(event.ufid): > + key = (b["watchlist"].Key * 1)(k) > + b["watchlist"].items_delete_batch(key) > + break > + > + > +def handle_flow_put(event): > + """Event handler for the `flow_put` action. This function will try > + to populate the watchlist based on the vswitchd emitting a put event > + to push an ODP flow key with associated actions into the kernel module""" > + > + if args.flow_keys or args.filter_flows is not None: > + key = decode_key(bytes(event.key)[: event.key_size]) > + flow_dict, flow_str = parse_flow_dict(key) > + # For each attribute that we're watching. > + if args.filter_flows is not None: > + if not compare_flow_to_target(args.filter_flows, flow_dict): > + find_and_delete_from_watchlist(event) > + return > + > + print( > + "{:<10} {:<18.9f} {:<36} {}".format( > + event.pid, > + event.ts / 1000000000, > + format_ufid(event.ufid), > + "Insert (put) flow to ovs kernel module.", > + ) > + ) > + > + if args.flow_keys and len(flow_str): > + flow_str_fields = flow_str.split("), ") > + flow_str = " " > + curlen = 4 > + for field in flow_str_fields: > + if curlen + len(field) > 79: > + flow_str += "\n " > + curlen = 4 > + if field[-1] != ")": > + field += ")" > + flow_str += field + ", " > + curlen += len(field) + 2 > + > + print(" - It holds the following key information:") > + print(flow_str) > + > + > +def compare_flow_to_target(target, flow): > + """Routine to compare two flow keys""" > + > + for key in target: > + if key not in flow: > + return False > + elif target[key] is True: > + continue > + elif target[key] == flow[key]: > + continue > + elif isinstance(target[key], dict) and isinstance(flow[key], dict): > + return compare_flow_to_target(target[key], flow[key]) > + else: > + return False > + return True > + > + > +# > +# parse_flow_str() > +# > +def parse_flow_str(flow_str): > + """Loosely parses an ODP flow key into a dict for further processing""" > + > + f_list = [i.strip(", ") for i in flow_str.split(")")] > + if f_list[-1] == "": > + f_list = f_list[:-1] > + flow_dict = {} > + for e in f_list: > + split_list = e.split("(") > + k = split_list[0] > + if len(split_list) == 1: > + flow_dict[k] = True > + elif split_list[1].count("=") == 0: > + flow_dict[k] = split_list[1] > + else: > + sub_dict = {} > + sublist = [i.strip() for i in split_list[1].split(",")] > + for subkey in sublist: > + brk = subkey.find("=") > + sub_dict[subkey[:brk]] = subkey[brk + 1 :] > + flow_dict[k] = sub_dict > + return flow_dict > + > + > +def print_expiration(event): > + """Prints a UFID eviction with a reason.""" > + ufid_str = format_ufid(event.ufid) > + > + if event.reason > len(FdrReasons): > + reason = f"Unknown reason '{event.reason}'" > + else: > + reason = FdrReasonStrings[event.reason] > + > + print( > + "{:<10} {:<18.9f} {:<36} {:<17}".format( > + event.pid, > + event.ts / 1000000000, > + ufid_str, > + reason, > + ) > + ) > + > + > +def decode_key(msg): > + """Decodes netlink OVS key attribute.""" > + bytes_left = len(msg) > + result = {} > + while bytes_left: > + if bytes_left < 4: > + break > + nla_len, nla_type = struct.unpack("=HH", msg[:4]) > + if nla_len < 4: > + break > + nla_data = msg[4:nla_len] > + if nla_len > bytes_left: > + nla_data = nla_data[: (bytes_left - 4)] > + break > + else: > + result[get_ovs_key_attr_str(nla_type)] = nla_data > + next_offset = (nla_len + 3) & (~3) > + msg = msg[next_offset:] > + bytes_left -= next_offset > + if bytes_left: > + print(f"INFO: Buffer truncated with {bytes_left} bytes left.") > + return result > + > + > +# > +# get_ovs_key_attr_str() > +# > +def get_ovs_key_attr_str(attr): > + ovs_key_attr = [ > + "OVS_KEY_ATTR_UNSPEC", > + "encap", > + "skb_priority", > + "in_port", > + "eth", > + "vlan", > + "eth_type", > + "ipv4", > + "ipv6", > + "tcp", > + "udp", > + "icmp", > + "icmpv6", > + "arp", > + "nd", > + "skb_mark", > + "tunnel", > + "sctp", > + "tcp_flags", > + "dp_hash", > + "recirc_id", > + "mpls", > + "ct_state", > + "ct_zone", > + "ct_mark", > + "ct_label", > + "ct_tuple4", > + "ct_tuple6", > + "nsh", > + ] > + > + if attr < 0 or attr > len(ovs_key_attr): > + return "<UNKNOWN>: {}".format(attr) > + return ovs_key_attr[attr] > + > + > +def parse_flow_dict(key_dict, decode=True): > + """Processes a flow key dict (see `parse_flow_str` or `decode_key`) and > + returns a tuple of both the final flow key dict, and a string that > + represents and ODP-like representation. Attempts to decode the actual > + data values if `decode` is true. Otherwise, this can be for a loose form > + of validation. Throws a KeyError when it encounters an unknown flow > + key.""" > + > + ret_str = "" > + parseable = {} > + skip = ["nsh", "tunnel", "mpls", "vlan"] > + need_byte_swap = ["ct_label"] > + ipv4addrs = ["ct_tuple4", "tunnel", "ipv4", "arp"] > + ipv6addrs = ["ipv6", "nd", "ct_tuple6"] > + macs = {"eth": [0, 1], "arp": [3, 4], "nd": [1, 2]} > + fields = [ > + ("OVS_KEY_ATTR_UNSPEC"), > + ("encap",), > + ("skb_priority", "<I"), > + ("in_port", "<I"), > + ("eth", "!6s6s", "src", "dst"), > + ("vlan",), > + ("eth_type", "!H"), > + ("ipv4", "!4s4s4B", "src", "dst", "proto", "tos", "ttl", "frag"), > + ( > + "ipv6", > + "!16s16s4s4B", > + "src", > + "dst", > + "label", > + "proto", > + "tclass", > + "hlimit", > + "frag", > + ), > + ("tcp", "!2H", "src", "dst"), > + ("udp", "!2H", "src", "dst"), > + ("icmp", "!2B", "type", "code"), > + ("icmpv6", "!2B", "type", "code"), > + ("arp", "!4s4sH6s6s", "sip", "tip", "op", "sha", "tha"), > + ("nd", "!16s6s6s", "target", "sll", "tll"), > + ("skb_mark", "<I"), > + ("tunnel",), > + ("sctp", "!2H", "src", "dst"), > + ("tcp_flags", "!H"), > + ("dp_hash", "<I"), > + ("recirc_id", "<I"), > + ("mpls",), > + ("ct_state", "<I"), > + ("ct_zone", "<H"), > + ("ct_mark", "<I"), > + ("ct_label", "!16s"), > + ("ct_tuple4", "!4s4s2HB", "src", "dst", "tp_src", "tp_dst", "proto"), > + ("ct_tuple6", "!16s16sB2H", "src", "dst", "proto", "tp_src", "tp_dst"), > + ("nsh",), > + ] > + for k, v in key_dict.items(): > + s = "" > + if k in skip: > + continue > + if decode and int.from_bytes(v, "big") == 0: > + parseable[k] = "0" > + continue > + if decode and k in need_byte_swap: > + v = int.from_bytes(v, "little").to_bytes(len(v), "big") > + attr = -1 > + found = False > + for f in fields: > + if k == f[0]: > + attr = fields.index(f) > + found = True > + break > + if not found: > + raise KeyError("Invalid flow field '%s'" % k) > + if decode and len(fields[attr]) > 1: > + data = list( > + struct.unpack( > + fields[attr][1], v[: struct.calcsize(fields[attr][1])] > + ) > + ) > + if k in ipv4addrs: > + if data[0].count(0) < 4: > + data[0] = str(IPv4Address(data[0])) > + else: > + data[0] = b"\x00" > + if data[1].count(0) < 4: > + data[1] = str(IPv4Address(data[1])) > + else: > + data[1] = b"\x00" > + if k in ipv6addrs: > + if data[0].count(0) < 16: > + data[0] = str(IPv6Address(data[0])) > + else: > + data[0] = b"\x00" > + if data[1].count(0) < len(data[1]): > + data[1] = str(IPv6Address(data[1])) > + else: > + data[1] = b"\x00" > + if k in macs.keys(): > + for e in macs[k]: > + if data[e].count(0) == 6: > + mac_str = b"\x00" > + else: > + mac_str = ":".join(["%02x" % i for i in data[e]]) > + data[e] = mac_str > + if decode and len(fields[attr]) > 2: > + field_dict = dict(zip(fields[attr][2:], data)) > + s = ", ".join(k + "=" + str(v) for k, v in field_dict.items()) > + elif decode and k != "eth_type": > + s = str(data[0]) > + field_dict = s > + else: > + if decode: > + s = hex(data[0]) > + field_dict = s > + ret_str += k + "(" + s + "), " > + parseable[k] = field_dict > + ret_str = ret_str[:-2] > + return (parseable, ret_str) > + > + > +def handle_event(ctx, data, size): > + """Dispatches to the correct event handler based on the event probe > + type. > + > + Once we grab the event, we have three cases. > + 1. It's a revalidator probe and the reason is nonzero: A flow is expiring > + 2. It's a revalidator probe and the reason is zero: flow revalidated > + 3. It's a flow_put probe. > + > + We will ignore case 2, and report all others. > + """ > + > + event = b["events"].event(data) > + if event.probe == Event.OP_FLOW_PUT: > + handle_flow_put(event) > + elif ( > + event.probe == Event.FLOW_RESULT > + and event.result == RevalResult.UKEY_DELETE > + ): > + print_expiration(event) > + > + > +def main(): > + # > + # Don't like these globals, but ctx passing does not work with the existing > + # open_ring_buffer() API :( > + # > + global b > + global args > + > + # > + # Argument parsing > + # > + parser = argparse.ArgumentParser() > + parser.add_argument( > + "--buffer-page-count", > + help="Number of BPF ring buffer pages, default 1024", > + type=int, > + default=1024, > + metavar="NUMBER", > + ) > + parser.add_argument( > + "-f", > + "--flow-key-size", > + help="Set maximum flow key size to capture, " > + "default 128 - see notes", > + type=buffer_size_type, > + default=128, > + metavar="[128-2048]", > + ) > + parser.add_argument( > + "-k", > + "--flow-keys", > + help="Print flow keys as flow strings", > + action="store_true", > + ) > + parser.add_argument( > + "-l", > + "--filter-flows", > + metavar="FLOW_STRING", > + help="Filter flows that match the specified " "ODP-like flow", > + type=str, > + default=None, > + nargs="*", > + ) > + parser.add_argument( > + "-P", > + "--pahole", > + metavar="PAHOLE", > + help="Pahole executable to use, default pahole", > + type=str, > + default="pahole", > + ) > + parser.add_argument( > + "-p", > + "--pid", > + metavar="VSWITCHD_PID", > + help="ovs-vswitchd's PID", > + type=int, > + default=None, > + ) > + parser.add_argument( > + "-D", > + "--debug", > + help="Enable eBPF debugging", > + type=int, > + const=0x3F, > + default=0, > + nargs="?", > + ) > + args = parser.parse_args() > + > + # > + # Find the PID of the ovs-vswitchd daemon if not specified. > + # > + if args.pid is None: > + for proc in psutil.process_iter(): > + if "ovs-vswitchd" in proc.name(): > + if args.pid is not None: > + err( > + "Error: Multiple ovs-vswitchd daemons running, " > + "use the -p option!" > + ) > + > + args.pid = proc.pid > + # > + # Error checking on input parameters > + # > + if args.pid is None: > + err("ERROR: Failed to find ovs-vswitchd's PID!") > + > + # > + # Attach the USDT probes > + # > + nit: unnecessary new line. > + try: > + u = USDT(pid=int(args.pid)) > + u.enable_probe(probe="op_flow_put", fn_name="usdt__op_flow_put") > + u.enable_probe(probe="flow_result", fn_name="usdt__flow_result") > + u.enable_probe( > + probe="flow_sweep_result", fn_name="usdt__flow_sweep_result" > + ) > + except USDTException as e: > + err("Failed to attach probes due to:\n" + str(e)) > + > + # > + # Attach the probes to the running process > + # > + source = bpf_src.replace( > + "<BUFFER_PAGE_COUNT>", str(args.buffer_page_count) > + ) > + > + source = source.replace( > + "<OVS_INCLUDE_DEFINITIONS>", > + get_ovs_definitions( > + ["udpif_key", "ovs_u128", "dpif_flow_put"], > + pid=args.pid, > + pahole=args.pahole, > + ), > + ) > + > + if args.filter_flows is None: > + filter_bool = 0 > + > + # Set the key size based on what the user wanted > + source = source.replace("<MAX_KEY_VAL>", str(args.flow_key_size)) > + else: > + filter_bool = 1 > + args.filter_flows = parse_flow_str(args.filter_flows[0]) > + > + # Run through the parser to make sure we only filter on fields we > + # understand > + parse_flow_dict(args.filter_flows, False) > + > + # This is hardcoded here because it doesn't make sense to shrink the > + # size, since the flow key might be missing fields that are matched in > + # the flow filter. > + source = source.replace("<MAX_KEY_VAL>", "2048") > + > + source = source.replace("<FILTER_BOOL>", str(filter_bool)) > + > + source = source.replace( > + "<EVENT_ENUM>", > + "\n".join([f"{event.name} = {event.value}," for event in Event]), > + ) > + > + b = BPF(text=source, usdt_contexts=[u], debug=args.debug) > + > + # > + # Print header > + # > + print( > + "{:<10} {:<18} {:<36} {:<17}".format( > + "TID", "TIME", "UFID", "EVENT/REASON" > + ) > + ) > + > + # > + # Dump out all events. > + # > + b["events"].open_ring_buffer(handle_event) > + while 1: > + try: > + b.ring_buffer_poll() > + except KeyboardInterrupt: > + break > + > + dropcnt = b.get_table("dropcnt") > + for k in dropcnt.keys(): > + count = dropcnt.sum(k).value > + if k.value == 0 and count > 0: > + print( > + "\n# WARNING: Not all flow operations were captured, {} were" > + " dropped!\n# Increase the BPF ring buffer size " > + "with the --buffer-page-count option.".format(count) > + ) > + > + > +# > +# Start main() as the default entry point > +# > +if __name__ == "__main__": > + main() > -- > 2.41.0
diff --git a/Documentation/topics/usdt-probes.rst b/Documentation/topics/usdt-probes.rst index e527f43bab..b9a6c54b29 100644 --- a/Documentation/topics/usdt-probes.rst +++ b/Documentation/topics/usdt-probes.rst @@ -214,8 +214,10 @@ Available probes in ``ovs_vswitchd``: - dpif_recv:recv_upcall - main:poll_block - main:run_start +- revalidate:flow_result - revalidate_ukey\_\_:entry - revalidate_ukey\_\_:exit +- revalidator_sweep\_\_:flow_result - udpif_revalidator:start_dump - udpif_revalidator:sweep_done @@ -443,6 +445,47 @@ sweep phase was completed. - ``utilities/usdt-scripts/reval_monitor.py`` +probe revalidate:flow_result +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +**Description**: +This probe is triggered when the revalidator has executed on a particular +flow key to make a determination whether to evict a flow, and the cause +for eviction. The revalidator runs periodically, and this probe will only +be triggered when a flow is flagged for revalidation. + +**Arguments**: + +- *arg0*: ``(struct udpif *) udpif`` +- *arg1*: ``(struct udpif_key *) ukey`` +- *arg2*: ``(enum reval_result) result`` +- *arg3*: ``(enum flow_del_reason) del_reason`` + +**Script references**: + +- ``utilities/usdt-scripts/flow_reval_monitor.py`` + + +probe revalidator_sweep\_\_:flow_result +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +**Description**: +This probe is placed in the path of the revalidator sweep, and is executed +under the condition that a flow entry is in an unexpected state, or the +flows were asked to be purged due to a user action. + +**Arguments**: + +- *arg0*: ``(struct udpif *) udpif`` +- *arg1*: ``(struct udpif_key *) ukey`` +- *arg2*: ``(enum reval_result) result`` +- *arg3*: ``(enum flow_del_reason) del_reason`` + +**Script references**: + +- ``utilities/usdt-scripts/flow_reval_monitor.py`` + + Adding your own probes ---------------------- diff --git a/ofproto/ofproto-dpif-upcall.c b/ofproto/ofproto-dpif-upcall.c index 9a5c5c29ce..d881956366 100644 --- a/ofproto/ofproto-dpif-upcall.c +++ b/ofproto/ofproto-dpif-upcall.c @@ -269,6 +269,20 @@ enum ukey_state { }; #define N_UKEY_STATES (UKEY_DELETED + 1) +enum flow_del_reason { + FDR_NONE = 0, /* No deletion reason for the flow. */ + FDR_AVOID_CACHING, /* Flow deleted to avoid caching. */ + FDR_BAD_ODP_FIT, /* The flow had a bad ODP flow fit. */ + FDR_FLOW_IDLE, /* The flow went unused and was deleted. */ + FDR_FLOW_LIMIT, /* All flows being killed. */ + FDR_FLOW_WILDCARDED, /* The flow needed a narrower wildcard mask. */ + FDR_NO_OFPROTO, /* The flow didn't have an associated ofproto. */ + FDR_PURGE, /* User action caused flows to be killed. */ + FDR_TOO_EXPENSIVE, /* The flow was too expensive to revalidate. */ + FDR_UPDATE_FAIL, /* Flow state transition was unexpected. */ + FDR_XLATION_ERROR, /* There was an error translating the flow. */ +}; + /* 'udpif_key's are responsible for tracking the little bit of state udpif * needs to do flow expiration which can't be pulled directly from the * datapath. They may be created by any handler or revalidator thread at any @@ -2279,7 +2293,8 @@ populate_xcache(struct udpif *udpif, struct udpif_key *ukey, static enum reval_result revalidate_ukey__(struct udpif *udpif, const struct udpif_key *ukey, uint16_t tcp_flags, struct ofpbuf *odp_actions, - struct recirc_refs *recircs, struct xlate_cache *xcache) + struct recirc_refs *recircs, struct xlate_cache *xcache, + enum flow_del_reason *del_reason) { struct xlate_out *xoutp; struct netflow *netflow; @@ -2300,11 +2315,13 @@ revalidate_ukey__(struct udpif *udpif, const struct udpif_key *ukey, netflow = NULL; if (xlate_ukey(udpif, ukey, tcp_flags, &ctx)) { + *del_reason = FDR_XLATION_ERROR; goto exit; } xoutp = &ctx.xout; if (xoutp->avoid_caching) { + *del_reason = FDR_AVOID_CACHING; goto exit; } @@ -2318,6 +2335,7 @@ revalidate_ukey__(struct udpif *udpif, const struct udpif_key *ukey, ofpbuf_clear(odp_actions); if (!ofproto) { + *del_reason = FDR_NO_OFPROTO; goto exit; } @@ -2329,6 +2347,7 @@ revalidate_ukey__(struct udpif *udpif, const struct udpif_key *ukey, if (odp_flow_key_to_mask(ukey->mask, ukey->mask_len, &dp_mask, &ctx.flow, NULL) == ODP_FIT_ERROR) { + *del_reason = FDR_BAD_ODP_FIT; goto exit; } @@ -2338,6 +2357,7 @@ revalidate_ukey__(struct udpif *udpif, const struct udpif_key *ukey, * down. Note that we do not know if the datapath has ignored any of the * wildcarded bits, so we may be overly conservative here. */ if (flow_wildcards_has_extra(&dp_mask, ctx.wc)) { + *del_reason = FDR_FLOW_WILDCARDED; goto exit; } @@ -2407,7 +2427,7 @@ static enum reval_result revalidate_ukey(struct udpif *udpif, struct udpif_key *ukey, const struct dpif_flow_stats *stats, struct ofpbuf *odp_actions, uint64_t reval_seq, - struct recirc_refs *recircs) + struct recirc_refs *recircs, enum flow_del_reason *del_reason) OVS_REQUIRES(ukey->mutex) { bool need_revalidate = ukey->reval_seq != reval_seq; @@ -2437,8 +2457,12 @@ revalidate_ukey(struct udpif *udpif, struct udpif_key *ukey, xlate_cache_clear(ukey->xcache); } result = revalidate_ukey__(udpif, ukey, push.tcp_flags, - odp_actions, recircs, ukey->xcache); - } /* else delete; too expensive to revalidate */ + odp_actions, recircs, ukey->xcache, + del_reason); + } else { + /* Delete, since it is too expensive to revalidate. */ + *del_reason = FDR_TOO_EXPENSIVE; + } } else if (!push.n_packets || ukey->xcache || !populate_xcache(udpif, ukey, push.tcp_flags)) { result = UKEY_KEEP; @@ -2838,6 +2862,7 @@ revalidate(struct revalidator *revalidator) for (f = flows; f < &flows[n_dumped]; f++) { long long int used = f->stats.used; struct recirc_refs recircs = RECIRC_REFS_EMPTY_INITIALIZER; + enum flow_del_reason del_reason = FDR_NONE; struct dpif_flow_stats stats = f->stats; enum reval_result result; struct udpif_key *ukey; @@ -2912,9 +2937,10 @@ revalidate(struct revalidator *revalidator) } if (kill_them_all || (used && used < now - max_idle)) { result = UKEY_DELETE; + del_reason = (kill_them_all) ? FDR_FLOW_LIMIT : FDR_FLOW_IDLE; } else { result = revalidate_ukey(udpif, ukey, &stats, &odp_actions, - reval_seq, &recircs); + reval_seq, &recircs, &del_reason); } ukey->dump_seq = dump_seq; @@ -2923,6 +2949,8 @@ revalidate(struct revalidator *revalidator) udpif_update_flow_pps(udpif, ukey, f); } + OVS_USDT_PROBE(revalidate, flow_result, udpif, ukey, result, + del_reason); if (result != UKEY_KEEP) { /* Takes ownership of 'recircs'. */ reval_op_init(&ops[n_ops++], result, udpif, ukey, &recircs, @@ -2975,6 +3003,7 @@ revalidator_sweep__(struct revalidator *revalidator, bool purge) size_t n_ops = 0; CMAP_FOR_EACH(ukey, cmap_node, &umap->cmap) { + enum flow_del_reason del_reason = FDR_NONE; enum ukey_state ukey_state; /* Handler threads could be holding a ukey lock while it installs a @@ -2993,6 +3022,7 @@ revalidator_sweep__(struct revalidator *revalidator, bool purge) if (purge || ukey_state == UKEY_INCONSISTENT) { result = UKEY_DELETE; + del_reason = purge ? FDR_PURGE : FDR_UPDATE_FAIL; } else if (!seq_mismatch) { result = UKEY_KEEP; } else { @@ -3000,13 +3030,15 @@ revalidator_sweep__(struct revalidator *revalidator, bool purge) COVERAGE_INC(revalidate_missed_dp_flow); memcpy(&stats, &ukey->stats, sizeof stats); result = revalidate_ukey(udpif, ukey, &stats, &odp_actions, - reval_seq, &recircs); + reval_seq, &recircs, &del_reason); } if (result != UKEY_KEEP) { /* Clears 'recircs' if filled by revalidate_ukey(). */ reval_op_init(&ops[n_ops++], result, udpif, ukey, &recircs, &odp_actions); } + OVS_USDT_PROBE(revalidator_sweep__, flow_sweep_result, udpif, + ukey, result, del_reason); } ovs_mutex_unlock(&ukey->mutex); diff --git a/utilities/automake.mk b/utilities/automake.mk index 9a2114df40..146b8c37fb 100644 --- a/utilities/automake.mk +++ b/utilities/automake.mk @@ -23,6 +23,7 @@ scripts_DATA += utilities/ovs-lib usdt_SCRIPTS += \ utilities/usdt-scripts/bridge_loop.bt \ utilities/usdt-scripts/dpif_nl_exec_monitor.py \ + utilities/usdt-scripts/flow_reval_monitor.py \ utilities/usdt-scripts/kernel_delay.py \ utilities/usdt-scripts/kernel_delay.rst \ utilities/usdt-scripts/reval_monitor.py \ @@ -72,6 +73,7 @@ EXTRA_DIST += \ utilities/docker/debian/build-kernel-modules.sh \ utilities/usdt-scripts/bridge_loop.bt \ utilities/usdt-scripts/dpif_nl_exec_monitor.py \ + utilities/usdt-scripts/flow_reval_monitor.py \ utilities/usdt-scripts/kernel_delay.py \ utilities/usdt-scripts/kernel_delay.rst \ utilities/usdt-scripts/reval_monitor.py \ @@ -146,6 +148,7 @@ FLAKE8_PYFILES += utilities/ovs-pcap.in \ utilities/ovs-tcpdump.in \ utilities/ovs-pipegen.py \ utilities/usdt-scripts/dpif_nl_exec_monitor.py \ + utilities/usdt-scripts/flow_reval_monitor.py \ utilities/usdt-scripts/upcall_monitor.py \ utilities/usdt-scripts/upcall_cost.py diff --git a/utilities/usdt-scripts/flow_reval_monitor.py b/utilities/usdt-scripts/flow_reval_monitor.py new file mode 100755 index 0000000000..dbd80b05a7 --- /dev/null +++ b/utilities/usdt-scripts/flow_reval_monitor.py @@ -0,0 +1,978 @@ +#!/usr/bin/env python3 +# +# Copyright (c) 2022-2024 Redhat, 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. +# +# Script information: +# ------------------- +# flow_reval_monitor.py uses the dpif_netlink_operate:flow_put and +# revalidator:flow_result USDT probes to monitor flow lifetimes and +# expiration events. By default, this will show all flow_put and flow +# expiration events, along with their reasons. This will look like so: +# +# TID TIME UFID EVENT/REASON +# 71828 1549.119959874 39f0f28f-33... Insert (put) flow to ovs kernel module. +# 71828 1549.420877223 850db41c-47... Insert (put) flow to ovs kernel module. +# 71828 1550.476923456 5bacfca9-fe... Insert (put) flow to ovs kernel module. +# 71832 1559.650192299 850db41c-47... Idle flow timed out +# 71832 1561.153332825 39f0f28f-33... Idle flow timed out +# 71832 1572.684316304 5bacfca9-fe... Idle flow timed out +# +# Flow key data can be printed using the --flow-keys option. This will +# print the equivalent datapath flow string. +# +# When filtering flows, the syntax is the same as used by +# `ovs-appctl dpctl/add-flow`. +# +# For a complete list of options, please use the '--help' or '-h' argument. +# +# Examples: +# +# To use the script on a running ovs-vswitchd to see flow keys and expiration +# events for flows with an ipv4 source of 192.168.10.10: +# $ ./flow_reval_monitor.py --flow-keys --filter-flows \ +# "ipv4(src=192.168.10.10)" +# TIME UFID EVENT/REASON +# 105082.457322742 ufid:f76fc899-376d-466b-bc74-0000b933eb97 flow_put +# ufid:f76fc899-376d-466b-bc74-0000b933eb97 has the following flow information: +# in_port(2), +# eth(src=0e:04:47:fc:74:51, dst=da:dc:c5:69:05:d7), \ +# eth_type(0x800), \ +# ipv4(src=192.168.10.10, dst=192.168.10.30, proto=1, tos=0, ttl=64,[...]), +# icmp(type=8, code=0) +# 105092.635450202 ufid:f76fc899-376d-466b-bc74-0000b933eb97 Flow timed out +# +# Notes: +# 1) No options are needed to attach when there is a single running instance +# of ovs-vswitchd. +# 2) If you're using the flow filtering option, it will only track flows that +# have been upcalled since the script began running. +# 3) When using the flow filtering option, the key size will likely need to +# be expanded to match on all the fields in the message. The default is +# kept small to keep the buffer copy sizes down when displaying +# flows (-k), but is hardcoded to 2048 when an actual filter (-l) is +# applied +# 4) The flow filtering format is a simplified form of the ODP syntax, and +# does not support masked matches, which means you will need to filter +# on exact details. The fields present are dependent on how the +# classifier and OFP rules form the ODP rules - not all fields may be +# present in a particular flow. +# 5) The flow_put filtering only happens for flows installed into the ovs +# kernel module. This means flows taking the HW offload path (ie: tc), +# or on DPDK side won't get matched. + +try: + from bcc import BPF + from bcc import USDT + from bcc import USDTException +except ModuleNotFoundError: + print("ERROR: Can't find the BPF Compiler Collection Tools.") + print("Please install them before running this script.") + exit(1) + +from enum import IntEnum +from ipaddress import IPv4Address, IPv6Address +from pathlib import Path + +import argparse +import psutil +import re +import struct +import subprocess +import sys + +# +# eBPF source code +# +bpf_src = """ +#include <linux/sched.h> + +#define MAX_KEY <MAX_KEY_VAL> +#define FLOW_FILTER <FILTER_BOOL> + +enum probe { <EVENT_ENUM> }; + +<OVS_INCLUDE_DEFINITIONS> + +struct event_t { + u64 ts; + u32 pid; + u32 result; + u32 reason; + u32 ufid[4]; + u64 key_size; + unsigned char key[MAX_KEY]; + enum probe probe; +}; + +BPF_HASH(watchlist, ovs_u128); +BPF_RINGBUF_OUTPUT(events, <BUFFER_PAGE_COUNT>); +BPF_TABLE("percpu_array", uint32_t, uint64_t, dropcnt, 1); + +/* Hack to make a 'static' like storage object. */ +BPF_TABLE("percpu_array", uint32_t, struct udpif_key, udpk, 1); + +static struct event_t *get_event(enum probe p) { + struct event_t *event = events.ringbuf_reserve(sizeof(struct event_t)); + + if (!event) { + dropcnt.increment(0); + return NULL; + } + + event->probe = p; + event->ts = bpf_ktime_get_ns(); + event->pid = bpf_get_current_pid_tgid(); + + return event; +} + +static int emit_flow_result(struct udpif_key *ukey, ovs_u128 ufid, + u32 result, u32 reason) { + struct event_t *event = NULL; + u64 *ufid_present = NULL; + + ufid_present = watchlist.lookup(&ufid); + if (FLOW_FILTER && !ufid_present) { + return 0; + } + + event = get_event(FLOW_RESULT); + if (!event) { + /* If we can't reserve the space in the ring buffer, return 1. */ + return 1; + } + + event->result = result; + event->reason = reason; + bpf_probe_read(&event->ufid, sizeof ufid, &ufid); + events.ringbuf_submit(event, 0); + + return 0; +} + +int usdt__flow_result(struct pt_regs *ctx) { + struct udpif_key *ukey = NULL; + u32 reason = 0; + u32 result = 0; + ovs_u128 ufid; + u32 zero = 0; + + ukey = udpk.lookup(&zero); + if (!ukey) { + return 1; + } + bpf_usdt_readarg_p(2, ctx, ukey, sizeof(struct udpif_key)); + bpf_usdt_readarg(3, ctx, &result); + bpf_usdt_readarg(4, ctx, &reason); + ufid = ukey->ufid; + + return emit_flow_result(ukey, ufid, result, reason); +} + +int usdt__flow_sweep_result(struct pt_regs *ctx) { + struct udpif_key *ukey = NULL; + u32 reason = 0; + u32 result = 0; + ovs_u128 ufid; + u32 zero = 0; + + ukey = udpk.lookup(&zero); + if (!ukey) { + return 1; + } + bpf_usdt_readarg_p(2, ctx, ukey, sizeof(struct udpif_key)); + bpf_usdt_readarg(3, ctx, &result); + bpf_usdt_readarg(4, ctx, &reason); + ufid = ukey->ufid; + + return emit_flow_result(ukey, ufid, result, reason); +} + +int usdt__op_flow_put(struct pt_regs *ctx) { + struct dpif_flow_put put; + ovs_u128 ufid; + + struct event_t *event = get_event(OP_FLOW_PUT); + if (!event) { + /* If we can't reserve the space in the ring buffer, return 1. */ + return 1; + } + + bpf_usdt_readarg_p(2, ctx, &put, sizeof put); + bpf_probe_read(&event->ufid, sizeof event->ufid, put.ufid); + bpf_probe_read(&ufid, sizeof ufid, &event->ufid); + if (put.key_len > MAX_KEY) { + put.key_len = MAX_KEY; + } + event->key_size = put.key_len; + bpf_probe_read(&event->key, put.key_len, put.key); + event->reason = 0; + events.ringbuf_submit(event, 0); + + watchlist.increment(ufid); + return 0; +} +""" + +Event = IntEnum("Event", ["OP_FLOW_PUT", "FLOW_RESULT"], start=0) +RevalResult = IntEnum( + "reval_result", + [ + "UKEY_KEEP", + "UKEY_DELETE", + "UKEY_MODIFY", + ], + start=0, +) +FdrReasons = IntEnum( + "flow_del_reason", + [ + "FDR_NONE", + "FDR_AVOID_CACHING", + "FDR_BAD_ODP_FIT", + "FDR_FLOW_IDLE", + "FDR_FLOW_LIMIT", + "FDR_FLOW_WILDCARDED", + "FDR_NO_OFPROTO", + "FDR_PURGE", + "FDR_TOO_EXPENSIVE", + "FDR_UPDATE_FAIL", + "FDR_XLATION_ERROR", + ], + start=0, +) + +FdrReasonStrings = [ + "No deletion reason", + "Cache avoidance flag set", + "Bad ODP flow fit", + "Idle flow timed out", + "Kill all flows condition detected", + "Mask too wide - need narrower match", + "No matching ofproto rules", + "Too expensive to revalidate", + "Purged with user action", + "Flow state inconsistent after updates", + "Flow translation error", +] + + +def err(msg, code=-1): + """Prints an error to stderr and exits""" + + print(msg, file=sys.stderr) + sys.exit(code) + + +def run_program(command): + """Invokes a new process and returns stdout. Note that this will honor + the PATH environment variable, so best to use it sparingly, or with a + full path to binary.""" + + try: + process = subprocess.run( + command, + stdout=subprocess.PIPE, + stderr=subprocess.STDOUT, + encoding="utf8", + check=True, + ) + + except subprocess.CalledProcessError as perror: + return perror.returncode, perror.stdout + + return 0, process.stdout + + +def get_ovs_definitions(objects, pahole="pahole", pid=None): + """Uses `pahole` or similar utility to pull object definitions from a + running OVS process. The objects argument can either be a string + or can be a list of strings. Optionally, pass a specific `pahole` + binary to use rather than the default. PID needs to be set.""" + + if pid is None: + raise ValueError("A valid pid value should be supplied!") + + if not isinstance(objects, list): + objects = [objects] + + if len(objects) == 0: + raise ValueError("Must supply at least one object!") + + vswitchd = Path(f"/proc/{pid}/exe").resolve() + + object_str = ",".join(objects) + + def run_pahole(debug_file): + """Helper designed for running pahole, or something with compatible + output""" + + error, result = run_program( + [pahole, "-C", object_str, "--compile", debug_file] + ) + + if error: + if f"pahole: {debug_file}: Invalid argument" not in result: + err( + "ERROR: Pahole failed to get ovs-vswitchd data " + "structures!\n{}".format( + re.sub( + "^", " " * 7, result.rstrip(), flags=re.MULTILINE + ) + ) + ) + + return None + + if bool(re.search("pahole: type .* not found", result)): + return None + + return result + + def run_readelf(bin_file): + """Helper designed for running readelf or something with compatible + output""" + + error, result = run_program( + ["readelf", "-n", "--debug-dump=links", bin_file] + ) + + if error: + err( + "ERROR: Failed 'readelf' on \"{}\"!\n{}".format( + bin_file, re.sub("^", " " * 7, result, flags=re.MULTILINE) + ) + ) + + return result + + def get_debug_file(bin_file): + """Runs readelf against the binary, and attempts to find the associated + debuginfo file.""" + elf_result = run_readelf(bin_file) + match = re.search("Build ID: ([0-9a-fA-F]+)", elf_result) + if not match: + err("ERROR: Can't find build ID to read debug symbols!") + + dbg_file = "/usr/lib/debug/.build-id/{}/{}.debug".format( + match.group(1)[:2], match.group(1)[2:] + ) + + return dbg_file + + def get_from_shared_library(debug_file): + ovs_libs = [ + "libofproto", + "libopenvswitch", + "libovsdb", + "libsflow", + "libvtep", + ] + error, ldd_result = run_program(["ldd", debug_file]) + + if error: + err( + "ERROR: Failed 'ldd' on \"{}\"!\n{}".format( + debug_file, + re.sub("^", " " * 7, ldd_result, flags=re.MULTILINE), + ) + ) + + for lib in ovs_libs: + match = re.search( + r"^\s*{}.* => (.*) \(.*\)$".format(lib), + ldd_result, + flags=re.MULTILINE, + ) + if match is None: + continue + + result = run_pahole(match.group(1)) + if result is None: + result = run_pahole(get_debug_file(match.group(1))) + + if result: + return result + + return None + + # + # First try to find the debug data as part of the executable. + # + result = run_pahole(vswitchd) + + if result is None: + print(f'INFO: Failed to find debug info in "{vswitchd}"!') + + # + # Get additional .debug information if available. + # + dbg_file = get_debug_file(vswitchd) + result = run_pahole(dbg_file) + if result is None: + print(f'INFO: Failed to find debug info in "{dbg_file}"!') + + # + # Try to get information from shared libraries if used. + # + result = get_from_shared_library(vswitchd) + + if result is None: + err(f"ERROR: Failed to find needed data structures through {pahole}") + + # + # We need an empty _Atomic definition to avoid compiler complaints. + # + result = "#define _Atomic\n" + result + + # + # Remove the uint64_t definition as it conflicts with the kernel one. + # + result = re.sub("^typedef.*uint64_t;$", "", result, flags=re.MULTILINE) + + return result + + +def buffer_size_type(astr, min=64, max=2048): + """Checks whether a string passed in is a number between min and max.""" + + value = int(astr) + if min <= value <= max: + return value + else: + raise argparse.ArgumentTypeError( + "value not in range {}-{}".format(min, max) + ) + + +def format_ufid(ufid): + """Formats a UFID object into a human readable form. If ufid is None, + prints "ufid:none" instead.""" + if ufid is None: + return "ufid:none" + + return "{:08x}-{:04x}-{:04x}-{:04x}-{:04x}{:08x}".format( + ufid[0], + ufid[1] >> 16, + ufid[1] & 0xFFFF, + ufid[2] >> 16, + ufid[2] & 0, + ufid[3], + ) + + +def find_and_delete_from_watchlist(event): + """If the event ufid is in the watchlist, delete it""" + + for k, _ in b["watchlist"].items(): + key_ufid = struct.unpack("=IIII", k) + if key_ufid == tuple(event.ufid): + key = (b["watchlist"].Key * 1)(k) + b["watchlist"].items_delete_batch(key) + break + + +def handle_flow_put(event): + """Event handler for the `flow_put` action. This function will try + to populate the watchlist based on the vswitchd emitting a put event + to push an ODP flow key with associated actions into the kernel module""" + + if args.flow_keys or args.filter_flows is not None: + key = decode_key(bytes(event.key)[: event.key_size]) + flow_dict, flow_str = parse_flow_dict(key) + # For each attribute that we're watching. + if args.filter_flows is not None: + if not compare_flow_to_target(args.filter_flows, flow_dict): + find_and_delete_from_watchlist(event) + return + + print( + "{:<10} {:<18.9f} {:<36} {}".format( + event.pid, + event.ts / 1000000000, + format_ufid(event.ufid), + "Insert (put) flow to ovs kernel module.", + ) + ) + + if args.flow_keys and len(flow_str): + flow_str_fields = flow_str.split("), ") + flow_str = " " + curlen = 4 + for field in flow_str_fields: + if curlen + len(field) > 79: + flow_str += "\n " + curlen = 4 + if field[-1] != ")": + field += ")" + flow_str += field + ", " + curlen += len(field) + 2 + + print(" - It holds the following key information:") + print(flow_str) + + +def compare_flow_to_target(target, flow): + """Routine to compare two flow keys""" + + for key in target: + if key not in flow: + return False + elif target[key] is True: + continue + elif target[key] == flow[key]: + continue + elif isinstance(target[key], dict) and isinstance(flow[key], dict): + return compare_flow_to_target(target[key], flow[key]) + else: + return False + return True + + +# +# parse_flow_str() +# +def parse_flow_str(flow_str): + """Loosely parses an ODP flow key into a dict for further processing""" + + f_list = [i.strip(", ") for i in flow_str.split(")")] + if f_list[-1] == "": + f_list = f_list[:-1] + flow_dict = {} + for e in f_list: + split_list = e.split("(") + k = split_list[0] + if len(split_list) == 1: + flow_dict[k] = True + elif split_list[1].count("=") == 0: + flow_dict[k] = split_list[1] + else: + sub_dict = {} + sublist = [i.strip() for i in split_list[1].split(",")] + for subkey in sublist: + brk = subkey.find("=") + sub_dict[subkey[:brk]] = subkey[brk + 1 :] + flow_dict[k] = sub_dict + return flow_dict + + +def print_expiration(event): + """Prints a UFID eviction with a reason.""" + ufid_str = format_ufid(event.ufid) + + if event.reason > len(FdrReasons): + reason = f"Unknown reason '{event.reason}'" + else: + reason = FdrReasonStrings[event.reason] + + print( + "{:<10} {:<18.9f} {:<36} {:<17}".format( + event.pid, + event.ts / 1000000000, + ufid_str, + reason, + ) + ) + + +def decode_key(msg): + """Decodes netlink OVS key attribute.""" + bytes_left = len(msg) + result = {} + while bytes_left: + if bytes_left < 4: + break + nla_len, nla_type = struct.unpack("=HH", msg[:4]) + if nla_len < 4: + break + nla_data = msg[4:nla_len] + if nla_len > bytes_left: + nla_data = nla_data[: (bytes_left - 4)] + break + else: + result[get_ovs_key_attr_str(nla_type)] = nla_data + next_offset = (nla_len + 3) & (~3) + msg = msg[next_offset:] + bytes_left -= next_offset + if bytes_left: + print(f"INFO: Buffer truncated with {bytes_left} bytes left.") + return result + + +# +# get_ovs_key_attr_str() +# +def get_ovs_key_attr_str(attr): + ovs_key_attr = [ + "OVS_KEY_ATTR_UNSPEC", + "encap", + "skb_priority", + "in_port", + "eth", + "vlan", + "eth_type", + "ipv4", + "ipv6", + "tcp", + "udp", + "icmp", + "icmpv6", + "arp", + "nd", + "skb_mark", + "tunnel", + "sctp", + "tcp_flags", + "dp_hash", + "recirc_id", + "mpls", + "ct_state", + "ct_zone", + "ct_mark", + "ct_label", + "ct_tuple4", + "ct_tuple6", + "nsh", + ] + + if attr < 0 or attr > len(ovs_key_attr): + return "<UNKNOWN>: {}".format(attr) + return ovs_key_attr[attr] + + +def parse_flow_dict(key_dict, decode=True): + """Processes a flow key dict (see `parse_flow_str` or `decode_key`) and + returns a tuple of both the final flow key dict, and a string that + represents and ODP-like representation. Attempts to decode the actual + data values if `decode` is true. Otherwise, this can be for a loose form + of validation. Throws a KeyError when it encounters an unknown flow + key.""" + + ret_str = "" + parseable = {} + skip = ["nsh", "tunnel", "mpls", "vlan"] + need_byte_swap = ["ct_label"] + ipv4addrs = ["ct_tuple4", "tunnel", "ipv4", "arp"] + ipv6addrs = ["ipv6", "nd", "ct_tuple6"] + macs = {"eth": [0, 1], "arp": [3, 4], "nd": [1, 2]} + fields = [ + ("OVS_KEY_ATTR_UNSPEC"), + ("encap",), + ("skb_priority", "<I"), + ("in_port", "<I"), + ("eth", "!6s6s", "src", "dst"), + ("vlan",), + ("eth_type", "!H"), + ("ipv4", "!4s4s4B", "src", "dst", "proto", "tos", "ttl", "frag"), + ( + "ipv6", + "!16s16s4s4B", + "src", + "dst", + "label", + "proto", + "tclass", + "hlimit", + "frag", + ), + ("tcp", "!2H", "src", "dst"), + ("udp", "!2H", "src", "dst"), + ("icmp", "!2B", "type", "code"), + ("icmpv6", "!2B", "type", "code"), + ("arp", "!4s4sH6s6s", "sip", "tip", "op", "sha", "tha"), + ("nd", "!16s6s6s", "target", "sll", "tll"), + ("skb_mark", "<I"), + ("tunnel",), + ("sctp", "!2H", "src", "dst"), + ("tcp_flags", "!H"), + ("dp_hash", "<I"), + ("recirc_id", "<I"), + ("mpls",), + ("ct_state", "<I"), + ("ct_zone", "<H"), + ("ct_mark", "<I"), + ("ct_label", "!16s"), + ("ct_tuple4", "!4s4s2HB", "src", "dst", "tp_src", "tp_dst", "proto"), + ("ct_tuple6", "!16s16sB2H", "src", "dst", "proto", "tp_src", "tp_dst"), + ("nsh",), + ] + for k, v in key_dict.items(): + s = "" + if k in skip: + continue + if decode and int.from_bytes(v, "big") == 0: + parseable[k] = "0" + continue + if decode and k in need_byte_swap: + v = int.from_bytes(v, "little").to_bytes(len(v), "big") + attr = -1 + found = False + for f in fields: + if k == f[0]: + attr = fields.index(f) + found = True + break + if not found: + raise KeyError("Invalid flow field '%s'" % k) + if decode and len(fields[attr]) > 1: + data = list( + struct.unpack( + fields[attr][1], v[: struct.calcsize(fields[attr][1])] + ) + ) + if k in ipv4addrs: + if data[0].count(0) < 4: + data[0] = str(IPv4Address(data[0])) + else: + data[0] = b"\x00" + if data[1].count(0) < 4: + data[1] = str(IPv4Address(data[1])) + else: + data[1] = b"\x00" + if k in ipv6addrs: + if data[0].count(0) < 16: + data[0] = str(IPv6Address(data[0])) + else: + data[0] = b"\x00" + if data[1].count(0) < len(data[1]): + data[1] = str(IPv6Address(data[1])) + else: + data[1] = b"\x00" + if k in macs.keys(): + for e in macs[k]: + if data[e].count(0) == 6: + mac_str = b"\x00" + else: + mac_str = ":".join(["%02x" % i for i in data[e]]) + data[e] = mac_str + if decode and len(fields[attr]) > 2: + field_dict = dict(zip(fields[attr][2:], data)) + s = ", ".join(k + "=" + str(v) for k, v in field_dict.items()) + elif decode and k != "eth_type": + s = str(data[0]) + field_dict = s + else: + if decode: + s = hex(data[0]) + field_dict = s + ret_str += k + "(" + s + "), " + parseable[k] = field_dict + ret_str = ret_str[:-2] + return (parseable, ret_str) + + +def handle_event(ctx, data, size): + """Dispatches to the correct event handler based on the event probe + type. + + Once we grab the event, we have three cases. + 1. It's a revalidator probe and the reason is nonzero: A flow is expiring + 2. It's a revalidator probe and the reason is zero: flow revalidated + 3. It's a flow_put probe. + + We will ignore case 2, and report all others. + """ + + event = b["events"].event(data) + if event.probe == Event.OP_FLOW_PUT: + handle_flow_put(event) + elif ( + event.probe == Event.FLOW_RESULT + and event.result == RevalResult.UKEY_DELETE + ): + print_expiration(event) + + +def main(): + # + # Don't like these globals, but ctx passing does not work with the existing + # open_ring_buffer() API :( + # + global b + global args + + # + # Argument parsing + # + parser = argparse.ArgumentParser() + parser.add_argument( + "--buffer-page-count", + help="Number of BPF ring buffer pages, default 1024", + type=int, + default=1024, + metavar="NUMBER", + ) + parser.add_argument( + "-f", + "--flow-key-size", + help="Set maximum flow key size to capture, " + "default 128 - see notes", + type=buffer_size_type, + default=128, + metavar="[128-2048]", + ) + parser.add_argument( + "-k", + "--flow-keys", + help="Print flow keys as flow strings", + action="store_true", + ) + parser.add_argument( + "-l", + "--filter-flows", + metavar="FLOW_STRING", + help="Filter flows that match the specified " "ODP-like flow", + type=str, + default=None, + nargs="*", + ) + parser.add_argument( + "-P", + "--pahole", + metavar="PAHOLE", + help="Pahole executable to use, default pahole", + type=str, + default="pahole", + ) + parser.add_argument( + "-p", + "--pid", + metavar="VSWITCHD_PID", + help="ovs-vswitchd's PID", + type=int, + default=None, + ) + parser.add_argument( + "-D", + "--debug", + help="Enable eBPF debugging", + type=int, + const=0x3F, + default=0, + nargs="?", + ) + args = parser.parse_args() + + # + # Find the PID of the ovs-vswitchd daemon if not specified. + # + if args.pid is None: + for proc in psutil.process_iter(): + if "ovs-vswitchd" in proc.name(): + if args.pid is not None: + err( + "Error: Multiple ovs-vswitchd daemons running, " + "use the -p option!" + ) + + args.pid = proc.pid + # + # Error checking on input parameters + # + if args.pid is None: + err("ERROR: Failed to find ovs-vswitchd's PID!") + + # + # Attach the USDT probes + # + + try: + u = USDT(pid=int(args.pid)) + u.enable_probe(probe="op_flow_put", fn_name="usdt__op_flow_put") + u.enable_probe(probe="flow_result", fn_name="usdt__flow_result") + u.enable_probe( + probe="flow_sweep_result", fn_name="usdt__flow_sweep_result" + ) + except USDTException as e: + err("Failed to attach probes due to:\n" + str(e)) + + # + # Attach the probes to the running process + # + source = bpf_src.replace( + "<BUFFER_PAGE_COUNT>", str(args.buffer_page_count) + ) + + source = source.replace( + "<OVS_INCLUDE_DEFINITIONS>", + get_ovs_definitions( + ["udpif_key", "ovs_u128", "dpif_flow_put"], + pid=args.pid, + pahole=args.pahole, + ), + ) + + if args.filter_flows is None: + filter_bool = 0 + + # Set the key size based on what the user wanted + source = source.replace("<MAX_KEY_VAL>", str(args.flow_key_size)) + else: + filter_bool = 1 + args.filter_flows = parse_flow_str(args.filter_flows[0]) + + # Run through the parser to make sure we only filter on fields we + # understand + parse_flow_dict(args.filter_flows, False) + + # This is hardcoded here because it doesn't make sense to shrink the + # size, since the flow key might be missing fields that are matched in + # the flow filter. + source = source.replace("<MAX_KEY_VAL>", "2048") + + source = source.replace("<FILTER_BOOL>", str(filter_bool)) + + source = source.replace( + "<EVENT_ENUM>", + "\n".join([f"{event.name} = {event.value}," for event in Event]), + ) + + b = BPF(text=source, usdt_contexts=[u], debug=args.debug) + + # + # Print header + # + print( + "{:<10} {:<18} {:<36} {:<17}".format( + "TID", "TIME", "UFID", "EVENT/REASON" + ) + ) + + # + # Dump out all events. + # + b["events"].open_ring_buffer(handle_event) + while 1: + try: + b.ring_buffer_poll() + except KeyboardInterrupt: + break + + dropcnt = b.get_table("dropcnt") + for k in dropcnt.keys(): + count = dropcnt.sum(k).value + if k.value == 0 and count > 0: + print( + "\n# WARNING: Not all flow operations were captured, {} were" + " dropped!\n# Increase the BPF ring buffer size " + "with the --buffer-page-count option.".format(count) + ) + + +# +# Start main() as the default entry point +# +if __name__ == "__main__": + main()