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![Kumar Kartikeya Dwivedi](/assets/img/avatar_default.png)
This adds support for the devmap_xmit tracepoint, and its multi device variant that can be used to obtain streams for each individual net_device to net_device redirection. This is useful for decomposing total xmit stats in xdp_monitor. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210821002010.845777-11-memxor@gmail.com
266 lines
7.1 KiB
C
266 lines
7.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* GPLv2, Copyright(c) 2017 Jesper Dangaard Brouer, Red Hat, Inc. */
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#include "xdp_sample.bpf.h"
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#include <bpf/bpf_tracing.h>
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#include <bpf/bpf_core_read.h>
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#include <bpf/bpf_helpers.h>
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array_map rx_cnt SEC(".maps");
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array_map redir_err_cnt SEC(".maps");
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array_map cpumap_enqueue_cnt SEC(".maps");
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array_map cpumap_kthread_cnt SEC(".maps");
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array_map exception_cnt SEC(".maps");
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array_map devmap_xmit_cnt SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_PERCPU_HASH);
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__uint(max_entries, 32 * 32);
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__type(key, u64);
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__type(value, struct datarec);
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} devmap_xmit_cnt_multi SEC(".maps");
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const volatile int nr_cpus = 0;
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/* These can be set before loading so that redundant comparisons can be DCE'd by
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* the verifier, and only actual matches are tried after loading tp_btf program.
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* This allows sample to filter tracepoint stats based on net_device.
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*/
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const volatile int from_match[32] = {};
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const volatile int to_match[32] = {};
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int cpumap_map_id = 0;
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/* Find if b is part of set a, but if a is empty set then evaluate to true */
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#define IN_SET(a, b) \
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({ \
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bool __res = !(a)[0]; \
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for (int i = 0; i < ARRAY_SIZE(a) && (a)[i]; i++) { \
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__res = (a)[i] == (b); \
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if (__res) \
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break; \
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} \
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__res; \
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})
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static __always_inline __u32 xdp_get_err_key(int err)
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{
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switch (err) {
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case 0:
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return 0;
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case -EINVAL:
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return 2;
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case -ENETDOWN:
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return 3;
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case -EMSGSIZE:
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return 4;
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case -EOPNOTSUPP:
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return 5;
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case -ENOSPC:
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return 6;
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default:
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return 1;
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}
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}
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static __always_inline int xdp_redirect_collect_stat(int from, int err)
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{
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u32 cpu = bpf_get_smp_processor_id();
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u32 key = XDP_REDIRECT_ERROR;
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struct datarec *rec;
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u32 idx;
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if (!IN_SET(from_match, from))
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return 0;
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key = xdp_get_err_key(err);
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idx = key * nr_cpus + cpu;
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rec = bpf_map_lookup_elem(&redir_err_cnt, &idx);
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if (!rec)
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return 0;
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if (key)
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NO_TEAR_INC(rec->dropped);
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else
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NO_TEAR_INC(rec->processed);
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return 0; /* Indicate event was filtered (no further processing)*/
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/*
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* Returning 1 here would allow e.g. a perf-record tracepoint
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* to see and record these events, but it doesn't work well
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* in-practice as stopping perf-record also unload this
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* bpf_prog. Plus, there is additional overhead of doing so.
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*/
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}
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SEC("tp_btf/xdp_redirect_err")
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int BPF_PROG(tp_xdp_redirect_err, const struct net_device *dev,
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const struct bpf_prog *xdp, const void *tgt, int err,
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const struct bpf_map *map, u32 index)
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{
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return xdp_redirect_collect_stat(dev->ifindex, err);
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}
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SEC("tp_btf/xdp_redirect_map_err")
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int BPF_PROG(tp_xdp_redirect_map_err, const struct net_device *dev,
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const struct bpf_prog *xdp, const void *tgt, int err,
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const struct bpf_map *map, u32 index)
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{
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return xdp_redirect_collect_stat(dev->ifindex, err);
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}
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SEC("tp_btf/xdp_redirect")
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int BPF_PROG(tp_xdp_redirect, const struct net_device *dev,
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const struct bpf_prog *xdp, const void *tgt, int err,
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const struct bpf_map *map, u32 index)
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{
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return xdp_redirect_collect_stat(dev->ifindex, err);
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}
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SEC("tp_btf/xdp_redirect_map")
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int BPF_PROG(tp_xdp_redirect_map, const struct net_device *dev,
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const struct bpf_prog *xdp, const void *tgt, int err,
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const struct bpf_map *map, u32 index)
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{
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return xdp_redirect_collect_stat(dev->ifindex, err);
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}
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SEC("tp_btf/xdp_cpumap_enqueue")
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int BPF_PROG(tp_xdp_cpumap_enqueue, int map_id, unsigned int processed,
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unsigned int drops, int to_cpu)
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{
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u32 cpu = bpf_get_smp_processor_id();
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struct datarec *rec;
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u32 idx;
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if (cpumap_map_id && cpumap_map_id != map_id)
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return 0;
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idx = to_cpu * nr_cpus + cpu;
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rec = bpf_map_lookup_elem(&cpumap_enqueue_cnt, &idx);
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if (!rec)
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return 0;
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NO_TEAR_ADD(rec->processed, processed);
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NO_TEAR_ADD(rec->dropped, drops);
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/* Record bulk events, then userspace can calc average bulk size */
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if (processed > 0)
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NO_TEAR_INC(rec->issue);
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/* Inception: It's possible to detect overload situations, via
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* this tracepoint. This can be used for creating a feedback
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* loop to XDP, which can take appropriate actions to mitigate
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* this overload situation.
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*/
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return 0;
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}
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SEC("tp_btf/xdp_cpumap_kthread")
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int BPF_PROG(tp_xdp_cpumap_kthread, int map_id, unsigned int processed,
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unsigned int drops, int sched, struct xdp_cpumap_stats *xdp_stats)
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{
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struct datarec *rec;
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u32 cpu;
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if (cpumap_map_id && cpumap_map_id != map_id)
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return 0;
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cpu = bpf_get_smp_processor_id();
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rec = bpf_map_lookup_elem(&cpumap_kthread_cnt, &cpu);
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if (!rec)
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return 0;
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NO_TEAR_ADD(rec->processed, processed);
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NO_TEAR_ADD(rec->dropped, drops);
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NO_TEAR_ADD(rec->xdp_pass, xdp_stats->pass);
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NO_TEAR_ADD(rec->xdp_drop, xdp_stats->drop);
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NO_TEAR_ADD(rec->xdp_redirect, xdp_stats->redirect);
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/* Count times kthread yielded CPU via schedule call */
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if (sched)
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NO_TEAR_INC(rec->issue);
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return 0;
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}
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SEC("tp_btf/xdp_exception")
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int BPF_PROG(tp_xdp_exception, const struct net_device *dev,
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const struct bpf_prog *xdp, u32 act)
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{
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u32 cpu = bpf_get_smp_processor_id();
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struct datarec *rec;
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u32 key = act, idx;
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if (!IN_SET(from_match, dev->ifindex))
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return 0;
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if (!IN_SET(to_match, dev->ifindex))
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return 0;
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if (key > XDP_REDIRECT)
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key = XDP_REDIRECT + 1;
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idx = key * nr_cpus + cpu;
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rec = bpf_map_lookup_elem(&exception_cnt, &idx);
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if (!rec)
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return 0;
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NO_TEAR_INC(rec->dropped);
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return 0;
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}
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SEC("tp_btf/xdp_devmap_xmit")
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int BPF_PROG(tp_xdp_devmap_xmit, const struct net_device *from_dev,
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const struct net_device *to_dev, int sent, int drops, int err)
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{
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struct datarec *rec;
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int idx_in, idx_out;
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u32 cpu;
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idx_in = from_dev->ifindex;
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idx_out = to_dev->ifindex;
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if (!IN_SET(from_match, idx_in))
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return 0;
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if (!IN_SET(to_match, idx_out))
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return 0;
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cpu = bpf_get_smp_processor_id();
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rec = bpf_map_lookup_elem(&devmap_xmit_cnt, &cpu);
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if (!rec)
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return 0;
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NO_TEAR_ADD(rec->processed, sent);
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NO_TEAR_ADD(rec->dropped, drops);
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/* Record bulk events, then userspace can calc average bulk size */
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NO_TEAR_INC(rec->info);
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/* Record error cases, where no frame were sent */
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/* Catch API error of drv ndo_xdp_xmit sent more than count */
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if (err || drops < 0)
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NO_TEAR_INC(rec->issue);
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return 0;
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}
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SEC("tp_btf/xdp_devmap_xmit")
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int BPF_PROG(tp_xdp_devmap_xmit_multi, const struct net_device *from_dev,
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const struct net_device *to_dev, int sent, int drops, int err)
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{
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struct datarec empty = {};
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struct datarec *rec;
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int idx_in, idx_out;
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u64 idx;
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idx_in = from_dev->ifindex;
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idx_out = to_dev->ifindex;
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idx = idx_in;
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idx = idx << 32 | idx_out;
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if (!IN_SET(from_match, idx_in))
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return 0;
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if (!IN_SET(to_match, idx_out))
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return 0;
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bpf_map_update_elem(&devmap_xmit_cnt_multi, &idx, &empty, BPF_NOEXIST);
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rec = bpf_map_lookup_elem(&devmap_xmit_cnt_multi, &idx);
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if (!rec)
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return 0;
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NO_TEAR_ADD(rec->processed, sent);
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NO_TEAR_ADD(rec->dropped, drops);
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NO_TEAR_INC(rec->info);
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if (err || drops < 0)
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NO_TEAR_INC(rec->issue);
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return 0;
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}
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