summaryrefslogtreecommitdiff
path: root/samples/bpf/xdp_monitor_kern.c
diff options
context:
space:
mode:
authorJesper Dangaard Brouer <brouer@redhat.com>2017-10-06 11:41:46 +0300
committerDavid S. Miller <davem@davemloft.net>2017-10-06 20:04:35 +0300
commit280b058d4801cb431477dc101a776e4b24995f2f (patch)
tree993a220ce48d529b5b3cd71a4af56429eaf4ef1b /samples/bpf/xdp_monitor_kern.c
parentf4ce0a0116bc90803adac10865f14429313cb2b6 (diff)
downloadlinux-280b058d4801cb431477dc101a776e4b24995f2f.tar.xz
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@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'samples/bpf/xdp_monitor_kern.c')
-rw-r--r--samples/bpf/xdp_monitor_kern.c38
1 files changed, 37 insertions, 1 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;
+}