diff options
Diffstat (limited to '')
| -rw-r--r-- | samples/bpf/xdp_monitor_kern.c | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/samples/bpf/xdp_monitor_kern.c b/samples/bpf/xdp_monitor_kern.c new file mode 100644 index 000000000..5c955b812 --- /dev/null +++ b/samples/bpf/xdp_monitor_kern.c @@ -0,0 +1,257 @@ +/* SPDX-License-Identifier: GPL-2.0 + * Copyright(c) 2017-2018 Jesper Dangaard Brouer, Red Hat Inc. + * + * XDP monitor tool, based on tracepoints + */ +#include <uapi/linux/bpf.h> +#include <bpf/bpf_helpers.h> + +struct { + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); + __type(key, u32); + __type(value, u64); + __uint(max_entries, 2); + /* TODO: have entries for all possible errno's */ +} redirect_err_cnt SEC(".maps"); + +#define XDP_UNKNOWN XDP_REDIRECT + 1 +struct { + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); + __type(key, u32); + __type(value, u64); + __uint(max_entries, XDP_UNKNOWN + 1); +} exception_cnt SEC(".maps"); + +/* Tracepoint format: /sys/kernel/debug/tracing/events/xdp/xdp_redirect/format + * Code in: kernel/include/trace/events/xdp.h + */ +struct xdp_redirect_ctx { + u64 __pad; // First 8 bytes are not accessible by bpf code + int prog_id; // offset:8; size:4; signed:1; + u32 act; // offset:12 size:4; signed:0; + int ifindex; // offset:16 size:4; signed:1; + int err; // offset:20 size:4; signed:1; + int to_ifindex; // offset:24 size:4; signed:1; + u32 map_id; // offset:28 size:4; signed:0; + int map_index; // offset:32 size:4; signed:1; +}; // offset:36 + +enum { + XDP_REDIRECT_SUCCESS = 0, + XDP_REDIRECT_ERROR = 1 +}; + +static __always_inline +int xdp_redirect_collect_stat(struct xdp_redirect_ctx *ctx) +{ + u32 key = XDP_REDIRECT_ERROR; + int err = ctx->err; + u64 *cnt; + + if (!err) + key = XDP_REDIRECT_SUCCESS; + + cnt = bpf_map_lookup_elem(&redirect_err_cnt, &key); + if (!cnt) + return 1; + *cnt += 1; + + return 0; /* Indicate event was filtered (no further processing)*/ + /* + * Returning 1 here would allow e.g. a perf-record tracepoint + * to see and record these events, but it doesn't work well + * in-practice as stopping perf-record also unload this + * bpf_prog. Plus, there is additional overhead of doing so. + */ +} + +SEC("tracepoint/xdp/xdp_redirect_err") +int trace_xdp_redirect_err(struct xdp_redirect_ctx *ctx) +{ + return xdp_redirect_collect_stat(ctx); +} + + +SEC("tracepoint/xdp/xdp_redirect_map_err") +int trace_xdp_redirect_map_err(struct xdp_redirect_ctx *ctx) +{ + return xdp_redirect_collect_stat(ctx); +} + +/* Likely unloaded when prog starts */ +SEC("tracepoint/xdp/xdp_redirect") +int trace_xdp_redirect(struct xdp_redirect_ctx *ctx) +{ + return xdp_redirect_collect_stat(ctx); +} + +/* Likely unloaded when prog starts */ +SEC("tracepoint/xdp/xdp_redirect_map") +int trace_xdp_redirect_map(struct xdp_redirect_ctx *ctx) +{ + return xdp_redirect_collect_stat(ctx); +} + +/* Tracepoint format: /sys/kernel/debug/tracing/events/xdp/xdp_exception/format + * Code in: kernel/include/trace/events/xdp.h + */ +struct xdp_exception_ctx { + u64 __pad; // First 8 bytes are not accessible by bpf code + int prog_id; // offset:8; size:4; signed:1; + u32 act; // offset:12; size:4; signed:0; + int ifindex; // offset:16; size:4; signed:1; +}; + +SEC("tracepoint/xdp/xdp_exception") +int trace_xdp_exception(struct xdp_exception_ctx *ctx) +{ + u64 *cnt; + u32 key; + + key = ctx->act; + if (key > XDP_REDIRECT) + key = XDP_UNKNOWN; + + cnt = bpf_map_lookup_elem(&exception_cnt, &key); + if (!cnt) + return 1; + *cnt += 1; + + return 0; +} + +/* Common stats data record shared with _user.c */ +struct datarec { + u64 processed; + u64 dropped; + u64 info; + u64 err; +}; +#define MAX_CPUS 64 + +struct { + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); + __type(key, u32); + __type(value, struct datarec); + __uint(max_entries, MAX_CPUS); +} cpumap_enqueue_cnt SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); + __type(key, u32); + __type(value, struct datarec); + __uint(max_entries, 1); +} cpumap_kthread_cnt SEC(".maps"); + +/* Tracepoint: /sys/kernel/debug/tracing/events/xdp/xdp_cpumap_enqueue/format + * Code in: kernel/include/trace/events/xdp.h + */ +struct cpumap_enqueue_ctx { + u64 __pad; // First 8 bytes are not accessible by bpf code + int map_id; // offset:8; size:4; signed:1; + u32 act; // offset:12; size:4; signed:0; + int cpu; // offset:16; size:4; signed:1; + unsigned int drops; // offset:20; size:4; signed:0; + unsigned int processed; // offset:24; size:4; signed:0; + int to_cpu; // offset:28; size:4; signed:1; +}; + +SEC("tracepoint/xdp/xdp_cpumap_enqueue") +int trace_xdp_cpumap_enqueue(struct cpumap_enqueue_ctx *ctx) +{ + u32 to_cpu = ctx->to_cpu; + struct datarec *rec; + + if (to_cpu >= MAX_CPUS) + return 1; + + rec = bpf_map_lookup_elem(&cpumap_enqueue_cnt, &to_cpu); + if (!rec) + return 0; + rec->processed += ctx->processed; + rec->dropped += ctx->drops; + + /* Record bulk events, then userspace can calc average bulk size */ + if (ctx->processed > 0) + rec->info += 1; + + return 0; +} + +/* Tracepoint: /sys/kernel/debug/tracing/events/xdp/xdp_cpumap_kthread/format + * Code in: kernel/include/trace/events/xdp.h + */ +struct cpumap_kthread_ctx { + u64 __pad; // First 8 bytes are not accessible by bpf code + int map_id; // offset:8; size:4; signed:1; + u32 act; // offset:12; size:4; signed:0; + int cpu; // offset:16; size:4; signed:1; + unsigned int drops; // offset:20; size:4; signed:0; + unsigned int processed; // offset:24; size:4; signed:0; + int sched; // offset:28; size:4; signed:1; +}; + +SEC("tracepoint/xdp/xdp_cpumap_kthread") +int trace_xdp_cpumap_kthread(struct cpumap_kthread_ctx *ctx) +{ + struct datarec *rec; + u32 key = 0; + + rec = bpf_map_lookup_elem(&cpumap_kthread_cnt, &key); + if (!rec) + return 0; + rec->processed += ctx->processed; + rec->dropped += ctx->drops; + + /* Count times kthread yielded CPU via schedule call */ + if (ctx->sched) + rec->info++; + + return 0; +} + +struct { + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); + __type(key, u32); + __type(value, struct datarec); + __uint(max_entries, 1); +} devmap_xmit_cnt SEC(".maps"); + +/* Tracepoint: /sys/kernel/debug/tracing/events/xdp/xdp_devmap_xmit/format + * Code in: kernel/include/trace/events/xdp.h + */ +struct devmap_xmit_ctx { + u64 __pad; // First 8 bytes are not accessible by bpf code + int from_ifindex; // offset:8; size:4; signed:1; + u32 act; // offset:12; size:4; signed:0; + int to_ifindex; // offset:16; size:4; signed:1; + int drops; // offset:20; size:4; signed:1; + int sent; // offset:24; size:4; signed:1; + int err; // offset:28; size:4; signed:1; +}; + +SEC("tracepoint/xdp/xdp_devmap_xmit") +int trace_xdp_devmap_xmit(struct devmap_xmit_ctx *ctx) +{ + struct datarec *rec; + u32 key = 0; + + rec = bpf_map_lookup_elem(&devmap_xmit_cnt, &key); + if (!rec) + return 0; + rec->processed += ctx->sent; + rec->dropped += ctx->drops; + + /* Record bulk events, then userspace can calc average bulk size */ + rec->info += 1; + + /* Record error cases, where no frame were sent */ + if (ctx->err) + rec->err++; + + /* Catch API error of drv ndo_xdp_xmit sent more than count */ + if (ctx->drops < 0) + rec->err++; + + return 1; +} |