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Message-ID: <150727930658.4460.1997718116533002464.stgit@firesoul>
Date: Fri, 06 Oct 2017 10:41:46 +0200
From: Jesper Dangaard Brouer <brouer@...hat.com>
To: netdev@...r.kernel.org, Andy Gospodarek <andy@...yhouse.net>
Cc: Daniel Borkmann <borkmann@...earbox.net>,
Alexei Starovoitov <alexei.starovoitov@...il.com>,
Jesper Dangaard Brouer <brouer@...hat.com>
Subject: [net-next PATCH 2/3] 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 <brouer@...hat.com>
---
samples/bpf/xdp_monitor_kern.c | 38 ++++++++++++++
samples/bpf/xdp_monitor_user.c | 108 +++++++++++++++++++++++++++++++---------
2 files changed, 121 insertions(+), 25 deletions(-)
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);
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