From 280b058d4801cb431477dc101a776e4b24995f2f Mon Sep 17 00:00:00 2001 From: Jesper Dangaard Brouer Date: Fri, 6 Oct 2017 10:41:46 +0200 Subject: samples/bpf: xdp_monitor also record xdp_exception tracepoint Also monitor the tracepoint xdp_exception. This tracepoint is usually invoked by the drivers. Programs themselves can activate this by returning XDP_ABORTED, which will drop the packet but also trigger the tracepoint. This is useful for distinguishing intentional (XDP_DROP) vs. ebpf-program error cases that cased a drop (XDP_ABORTED). Drivers also use this tracepoint for reporting on XDP actions that are unknown to the specific driver. This can help the user to detect if a driver e.g. doesn't implement XDP_REDIRECT yet. Signed-off-by: Jesper Dangaard Brouer Signed-off-by: David S. Miller --- samples/bpf/xdp_monitor_kern.c | 38 ++++++++++++++- samples/bpf/xdp_monitor_user.c | 108 ++++++++++++++++++++++++++++++++--------- 2 files changed, 121 insertions(+), 25 deletions(-) (limited to 'samples') diff --git a/samples/bpf/xdp_monitor_kern.c b/samples/bpf/xdp_monitor_kern.c index cc7e19d2ad76..2fe2f761a0d0 100644 --- a/samples/bpf/xdp_monitor_kern.c +++ b/samples/bpf/xdp_monitor_kern.c @@ -13,6 +13,14 @@ struct bpf_map_def SEC("maps") redirect_err_cnt = { /* TODO: have entries for all possible errno's */ }; +#define XDP_UNKNOWN XDP_REDIRECT + 1 +struct bpf_map_def SEC("maps") exception_cnt = { + .type = BPF_MAP_TYPE_PERCPU_ARRAY, + .key_size = sizeof(u32), + .value_size = sizeof(u64), + .max_entries = XDP_UNKNOWN + 1, +}; + /* Tracepoint format: /sys/kernel/debug/tracing/events/xdp/xdp_redirect/format * Code in: kernel/include/trace/events/xdp.h */ @@ -44,7 +52,7 @@ int xdp_redirect_collect_stat(struct xdp_redirect_ctx *ctx) cnt = bpf_map_lookup_elem(&redirect_err_cnt, &key); if (!cnt) - return 0; + return 1; *cnt += 1; return 0; /* Indicate event was filtered (no further processing)*/ @@ -82,3 +90,31 @@ 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; +} diff --git a/samples/bpf/xdp_monitor_user.c b/samples/bpf/xdp_monitor_user.c index c5ab8b776973..97c3456c11b2 100644 --- a/samples/bpf/xdp_monitor_user.c +++ b/samples/bpf/xdp_monitor_user.c @@ -89,6 +89,23 @@ static const char *err2str(int err) return redir_names[err]; return NULL; } +/* enum xdp_action */ +#define XDP_UNKNOWN XDP_REDIRECT + 1 +#define XDP_ACTION_MAX (XDP_UNKNOWN + 1) +static const char *xdp_action_names[XDP_ACTION_MAX] = { + [XDP_ABORTED] = "XDP_ABORTED", + [XDP_DROP] = "XDP_DROP", + [XDP_PASS] = "XDP_PASS", + [XDP_TX] = "XDP_TX", + [XDP_REDIRECT] = "XDP_REDIRECT", + [XDP_UNKNOWN] = "XDP_UNKNOWN", +}; +static const char *action2str(int action) +{ + if (action < XDP_ACTION_MAX) + return xdp_action_names[action]; + return NULL; +} struct record { __u64 counter; @@ -97,6 +114,7 @@ struct record { struct stats_record { struct record xdp_redir[REDIR_RES_MAX]; + struct record xdp_exception[XDP_ACTION_MAX]; }; static void stats_print_headers(bool err_only) @@ -104,39 +122,72 @@ static void stats_print_headers(bool err_only) if (err_only) printf("\n%s\n", __doc_err_only__); - printf("%-14s %-10s %-18s %-9s\n", - "XDP_REDIRECT", "pps ", "pps-human-readable", "measure-period"); + printf("%-14s %-11s %-10s %-18s %-9s\n", + "ACTION", "result", "pps ", "pps-human-readable", "measure-period"); +} + +static double calc_period(struct record *r, struct record *p) +{ + double period_ = 0; + __u64 period = 0; + + period = r->timestamp - p->timestamp; + if (period > 0) + period_ = ((double) period / NANOSEC_PER_SEC); + + return period_; +} + +static double calc_pps(struct record *r, struct record *p, double period) +{ + __u64 packets = 0; + double pps = 0; + + if (period > 0) { + packets = r->counter - p->counter; + pps = packets / period; + } + return pps; } static void stats_print(struct stats_record *rec, struct stats_record *prev, bool err_only) { + double period = 0, pps = 0; + struct record *r, *p; int i = 0; + char *fmt = "%-14s %-11s %-10.0f %'-18.0f %f\n"; + + /* tracepoint: xdp:xdp_redirect_* */ if (err_only) i = REDIR_ERROR; for (; i < REDIR_RES_MAX; i++) { - struct record *r = &rec->xdp_redir[i]; - struct record *p = &prev->xdp_redir[i]; - __u64 period = 0; - __u64 packets = 0; - double pps = 0; - double period_ = 0; + r = &rec->xdp_redir[i]; + p = &prev->xdp_redir[i]; if (p->timestamp) { - packets = r->counter - p->counter; - period = r->timestamp - p->timestamp; - if (period > 0) { - period_ = ((double) period / NANOSEC_PER_SEC); - pps = packets / period_; - } + period = calc_period(r, p); + pps = calc_pps(r, p, period); } + printf(fmt, "XDP_REDIRECT", err2str(i), pps, pps, period); + } - printf("%-14s %-10.0f %'-18.0f %f\n", - err2str(i), pps, pps, period_); + /* tracepoint: xdp:xdp_exception */ + for (i = 0; i < XDP_ACTION_MAX; i++) { + r = &rec->xdp_exception[i]; + p = &prev->xdp_exception[i]; + if (p->timestamp) { + period = calc_period(r, p); + pps = calc_pps(r, p, period); + } + if (pps > 0) + printf(fmt, action2str(i), "Exception", + pps, pps, period); } + printf("\n"); } static __u64 get_key32_value64_percpu(int fd, __u32 key) @@ -160,25 +211,33 @@ static __u64 get_key32_value64_percpu(int fd, __u32 key) return sum; } -static bool stats_collect(int fd, struct stats_record *rec) +static bool stats_collect(struct stats_record *rec) { + int fd; int i; /* TODO: Detect if someone unloaded the perf event_fd's, as * this can happen by someone running perf-record -e */ + fd = map_data[0].fd; /* map0: redirect_err_cnt */ for (i = 0; i < REDIR_RES_MAX; i++) { rec->xdp_redir[i].timestamp = gettime(); rec->xdp_redir[i].counter = get_key32_value64_percpu(fd, i); } + + fd = map_data[1].fd; /* map1: exception_cnt */ + for (i = 0; i < XDP_ACTION_MAX; i++) { + rec->xdp_exception[i].timestamp = gettime(); + rec->xdp_exception[i].counter = get_key32_value64_percpu(fd, i); + } + return true; } static void stats_poll(int interval, bool err_only) { struct stats_record rec, prev; - int map_fd; memset(&rec, 0, sizeof(rec)); @@ -190,16 +249,17 @@ static void stats_poll(int interval, bool err_only) printf("\n%s", __doc__); /* TODO Need more advanced stats on error types */ - if (verbose) - printf(" - Stats map: %s\n", map_data[0].name); - map_fd = map_data[0].fd; - - stats_print_headers(err_only); + if (verbose) { + printf(" - Stats map0: %s\n", map_data[0].name); + printf(" - Stats map1: %s\n", map_data[1].name); + printf("\n"); + } fflush(stdout); while (1) { memcpy(&prev, &rec, sizeof(rec)); - stats_collect(map_fd, &rec); + stats_collect(&rec); + stats_print_headers(err_only); stats_print(&rec, &prev, err_only); fflush(stdout); sleep(interval); -- cgit v1.2.3-59-g8ed1b