89 lines
2.4 KiB
C
89 lines
2.4 KiB
C
/* XDP monitor tool, based on tracepoints
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*
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* Copyright(c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
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*/
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#include <uapi/linux/bpf.h>
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#include "bpf_helpers.h"
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struct bpf_map_def SEC("maps") redirect_err_cnt = {
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.type = BPF_MAP_TYPE_PERCPU_ARRAY,
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.key_size = sizeof(u32),
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.value_size = sizeof(u64),
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.max_entries = 2,
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/* TODO: have entries for all possible errno's */
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};
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/* Tracepoint format: /sys/kernel/debug/tracing/events/xdp/xdp_redirect/format
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* Code in: kernel/include/trace/events/xdp.h
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*/
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struct xdp_redirect_ctx {
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unsigned short common_type; // offset:0; size:2; signed:0;
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unsigned char common_flags; // offset:2; size:1; signed:0;
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unsigned char common_preempt_count;// offset:3; size:1; signed:0;
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int common_pid; // offset:4; size:4; signed:1;
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int prog_id; // offset:8; size:4; signed:1;
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u32 act; // offset:12 size:4; signed:0;
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int ifindex; // offset:16 size:4; signed:1;
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int err; // offset:20 size:4; signed:1;
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int to_ifindex; // offset:24 size:4; signed:1;
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u32 map_id; // offset:28 size:4; signed:0;
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int map_index; // offset:32 size:4; signed:1;
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}; // offset:36
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enum {
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XDP_REDIRECT_SUCCESS = 0,
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XDP_REDIRECT_ERROR = 1
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};
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static __always_inline
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int xdp_redirect_collect_stat(struct xdp_redirect_ctx *ctx)
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{
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u32 key = XDP_REDIRECT_ERROR;
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int err = ctx->err;
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u64 *cnt;
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if (!err)
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key = XDP_REDIRECT_SUCCESS;
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cnt = bpf_map_lookup_elem(&redirect_err_cnt, &key);
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if (!cnt)
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return 0;
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*cnt += 1;
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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("tracepoint/xdp/xdp_redirect_err")
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int trace_xdp_redirect_err(struct xdp_redirect_ctx *ctx)
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{
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return xdp_redirect_collect_stat(ctx);
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}
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SEC("tracepoint/xdp/xdp_redirect_map_err")
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int trace_xdp_redirect_map_err(struct xdp_redirect_ctx *ctx)
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{
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return xdp_redirect_collect_stat(ctx);
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}
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/* Likely unloaded when prog starts */
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SEC("tracepoint/xdp/xdp_redirect")
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int trace_xdp_redirect(struct xdp_redirect_ctx *ctx)
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{
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return xdp_redirect_collect_stat(ctx);
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}
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/* Likely unloaded when prog starts */
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SEC("tracepoint/xdp/xdp_redirect_map")
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int trace_xdp_redirect_map(struct xdp_redirect_ctx *ctx)
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{
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return xdp_redirect_collect_stat(ctx);
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}
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