These eBPF tracepoint programs export data that is consumed by the
helpers added in the previous commit.
Also add support int the Makefile to generate a vmlinux.h header that
would be used by other bpf.c files in later commits.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
---
samples/bpf/Makefile | 25 ++++
samples/bpf/xdp_sample.bpf.c | 267 +++++++++++++++++++++++++++++++++++
samples/bpf/xdp_sample.bpf.h | 62 ++++++++
3 files changed, 354 insertions(+)
create mode 100644 samples/bpf/xdp_sample.bpf.c
create mode 100644 samples/bpf/xdp_sample.bpf.h
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index d8fc3e6930f9..4a3151fa163f 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -277,6 +277,11 @@ $(LIBBPF): FORCE
$(MAKE) -C $(dir $@) RM='rm -rf' EXTRA_CFLAGS="$(TPROGS_CFLAGS)" \
LDFLAGS=$(TPROGS_LDFLAGS) srctree=$(BPF_SAMPLES_PATH)/../../ O=
+BPFTOOLDIR := $(TOOLS_PATH)/bpf/bpftool
+BPFTOOL := $(BPFTOOLDIR)/bpftool
+$(BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile)
+ $(MAKE) -C $(BPFTOOLDIR) srctree=$(BPF_SAMPLES_PATH)/../../
+
$(obj)/syscall_nrs.h: $(obj)/syscall_nrs.s FORCE
$(call filechk,offsets,__SYSCALL_NRS_H__)
@@ -314,6 +319,26 @@ $(obj)/hbm_edt_kern.o: $(src)/hbm.h $(src)/hbm_kern.h
-include $(BPF_SAMPLES_PATH)/Makefile.target
+VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux) \
+ $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux) \
+ ../../../../vmlinux \
+ /sys/kernel/btf/vmlinux \
+ /boot/vmlinux-$(shell uname -r)
+VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS))))
+
+ifeq ($(VMLINUX_BTF),)
+$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)")
+endif
+
+$(obj)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL)
+ifeq ($(VMLINUX_H),)
+ $(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@
+else
+ $(Q)cp "$(VMLINUX_H)" $@
+endif
+
+clean-files += vmlinux.h
+
# asm/sysreg.h - inline assembly used by it is incompatible with llvm.
# But, there is no easy way to fix it, so just exclude it since it is
# useless for BPF samples.
diff --git a/samples/bpf/xdp_sample.bpf.c b/samples/bpf/xdp_sample.bpf.c
new file mode 100644
index 000000000000..d714776edd72
--- /dev/null
+++ b/samples/bpf/xdp_sample.bpf.c
@@ -0,0 +1,267 @@
+// SPDX-License-Identifier: GPL-2.0
+/* GPLv2, Copyright(c) 2017 Jesper Dangaard Brouer, Red Hat, Inc. */
+#include "xdp_sample.bpf.h"
+
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_helpers.h>
+
+struct sample_data sample_data;
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERCPU_HASH);
+ __uint(max_entries, 32 * 32);
+ __type(key, u64);
+ __type(value, struct datarec);
+} devmap_xmit_cnt_multi SEC(".maps");
+
+/* These can be set before loading so that redundant comparisons can be DCE'd by
+ * the verifier, and only actual matches are tried after loading tp_btf program.
+ * This allows sample to filter tracepoint stats based on net_device.
+ */
+const volatile int from_match[32] = {};
+const volatile int to_match[32] = {};
+
+int cpumap_map_id = 0;
+
+/* Find if b is part of set a, but if a is empty set then evaluate to true */
+#define IN_SET(a, b) \
+ ({ \
+ bool __res = !(a)[0]; \
+ for (int i = 0; i < ELEMENTS_OF(a) && (a)[i]; i++) { \
+ __res = (a)[i] == (b); \
+ if (__res) \
+ break; \
+ } \
+ __res; \
+ })
+
+static __always_inline __u32 xdp_get_err_key(int err)
+{
+ switch (err) {
+ case 0:
+ return 0;
+ case -EINVAL:
+ return 2;
+ case -ENETDOWN:
+ return 3;
+ case -EMSGSIZE:
+ return 4;
+ case -EOPNOTSUPP:
+ return 5;
+ case -ENOSPC:
+ return 6;
+ default:
+ return 1;
+ }
+}
+
+static __always_inline int xdp_redirect_collect_stat(int from, int err)
+{
+ u32 cpu = bpf_get_smp_processor_id();
+ u32 key = XDP_REDIRECT_ERROR;
+ struct datarec *rec;
+ u32 idx;
+
+ if (!IN_SET(from_match, from))
+ return 0;
+
+ key = xdp_get_err_key(err);
+
+ idx = key * MAX_CPUS + cpu;
+ if (idx >= ELEMENTS_OF(sample_data.redirect_err_cnt))
+ return 0;
+
+ rec = &sample_data.redirect_err_cnt[idx];
+ if (key)
+ NO_TEAR_INC(rec->dropped);
+ else
+ NO_TEAR_INC(rec->processed);
+ 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("tp_btf/xdp_redirect_err")
+int BPF_PROG(tp_xdp_redirect_err, const struct net_device *dev,
+ const struct bpf_prog *xdp, const void *tgt, int err,
+ const struct bpf_map *map, u32 index)
+{
+ return xdp_redirect_collect_stat(dev->ifindex, err);
+}
+
+SEC("tp_btf/xdp_redirect_map_err")
+int BPF_PROG(tp_xdp_redirect_map_err, const struct net_device *dev,
+ const struct bpf_prog *xdp, const void *tgt, int err,
+ const struct bpf_map *map, u32 index)
+{
+ return xdp_redirect_collect_stat(dev->ifindex, err);
+}
+
+SEC("tp_btf/xdp_redirect")
+int BPF_PROG(tp_xdp_redirect, const struct net_device *dev,
+ const struct bpf_prog *xdp, const void *tgt, int err,
+ const struct bpf_map *map, u32 index)
+{
+ return xdp_redirect_collect_stat(dev->ifindex, err);
+}
+
+SEC("tp_btf/xdp_redirect_map")
+int BPF_PROG(tp_xdp_redirect_map, const struct net_device *dev,
+ const struct bpf_prog *xdp, const void *tgt, int err,
+ const struct bpf_map *map, u32 index)
+{
+ return xdp_redirect_collect_stat(dev->ifindex, err);
+}
+
+SEC("tp_btf/xdp_exception")
+int BPF_PROG(tp_xdp_exception, const struct net_device *dev,
+ const struct bpf_prog *xdp, u32 act)
+{
+ u32 cpu = bpf_get_smp_processor_id();
+ struct datarec *rec;
+ u32 key = act, idx;
+
+ if (!IN_SET(from_match, dev->ifindex))
+ return 0;
+ if (!IN_SET(to_match, dev->ifindex))
+ return 0;
+
+ if (key > XDP_REDIRECT)
+ key = XDP_REDIRECT + 1;
+
+ idx = key * MAX_CPUS + cpu;
+ if (idx >= ELEMENTS_OF(sample_data.exception_cnt))
+ return 0;
+
+ rec = &sample_data.exception_cnt[idx];
+ NO_TEAR_INC(rec->dropped);
+
+ return 0;
+}
+
+SEC("tp_btf/xdp_cpumap_enqueue")
+int BPF_PROG(tp_xdp_cpumap_enqueue, int map_id, unsigned int processed,
+ unsigned int drops, int to_cpu)
+{
+ u32 cpu = bpf_get_smp_processor_id();
+ struct datarec *rec;
+ u32 idx;
+
+ if (cpumap_map_id && cpumap_map_id != map_id)
+ return 0;
+
+ idx = to_cpu * MAX_CPUS + cpu;
+ if (idx >= ELEMENTS_OF(sample_data.cpumap_enqueue_cnt))
+ return 0;
+
+ rec = &sample_data.cpumap_enqueue_cnt[idx];
+ NO_TEAR_ADD(rec->processed, processed);
+ NO_TEAR_ADD(rec->dropped, drops);
+ /* Record bulk events, then userspace can calc average bulk size */
+ if (processed > 0)
+ NO_TEAR_INC(rec->issue);
+ /* Inception: It's possible to detect overload situations, via
+ * this tracepoint. This can be used for creating a feedback
+ * loop to XDP, which can take appropriate actions to mitigate
+ * this overload situation.
+ */
+ return 0;
+}
+
+SEC("tp_btf/xdp_cpumap_kthread")
+int BPF_PROG(tp_xdp_cpumap_kthread, int map_id, unsigned int processed,
+ unsigned int drops, int sched, struct xdp_cpumap_stats *xdp_stats)
+{
+ struct datarec *rec;
+ u32 cpu;
+
+ if (cpumap_map_id && cpumap_map_id != map_id)
+ return 0;
+
+ /* XXX: Moving assignment for index before map_id check fails
+ * verification when compiled using clang-12, likewise for other places.
+ */
+ cpu = bpf_get_smp_processor_id();
+ if (cpu >= ELEMENTS_OF(sample_data.cpumap_kthread_cnt))
+ return 0;
+
+ rec = &sample_data.cpumap_kthread_cnt[cpu];
+ NO_TEAR_ADD(rec->processed, processed);
+ NO_TEAR_ADD(rec->dropped, drops);
+ NO_TEAR_ADD(rec->xdp_pass, xdp_stats->pass);
+ NO_TEAR_ADD(rec->xdp_drop, xdp_stats->drop);
+ NO_TEAR_ADD(rec->xdp_redirect, xdp_stats->redirect);
+ /* Count times kthread yielded CPU via schedule call */
+ if (sched)
+ NO_TEAR_INC(rec->issue);
+ return 0;
+}
+
+SEC("tp_btf/xdp_devmap_xmit")
+int BPF_PROG(tp_xdp_devmap_xmit, const struct net_device *from_dev,
+ const struct net_device *to_dev, int sent, int drops, int err)
+{
+ struct datarec *rec;
+ int idx_in, idx_out;
+ u32 cpu;
+
+ idx_in = from_dev->ifindex;
+ idx_out = to_dev->ifindex;
+
+ if (!IN_SET(from_match, idx_in))
+ return 0;
+ if (!IN_SET(to_match, idx_out))
+ return 0;
+
+ cpu = bpf_get_smp_processor_id();
+ if (cpu >= ELEMENTS_OF(sample_data.devmap_xmit_cnt))
+ return 0;
+
+ rec = &sample_data.devmap_xmit_cnt[cpu];
+ NO_TEAR_ADD(rec->processed, sent);
+ NO_TEAR_ADD(rec->dropped, drops);
+ /* Record bulk events, then userspace can calc average bulk size */
+ NO_TEAR_INC(rec->info);
+ /* Record error cases, where no frame were sent */
+ /* Catch API error of drv ndo_xdp_xmit sent more than count */
+ if (err || drops < 0)
+ NO_TEAR_INC(rec->issue);
+ return 0;
+}
+
+SEC("tp_btf/xdp_devmap_xmit")
+int BPF_PROG(tp_xdp_devmap_xmit_multi, const struct net_device *from_dev,
+ const struct net_device *to_dev, int sent, int drops, int err)
+{
+ struct datarec empty = {};
+ struct datarec *rec;
+ int idx_in, idx_out;
+ u64 idx;
+
+ idx_in = from_dev->ifindex;
+ idx_out = to_dev->ifindex;
+ idx = idx_in;
+ idx = idx << 32 | idx_out;
+
+ if (!IN_SET(from_match, idx_in))
+ return 0;
+ if (!IN_SET(to_match, idx_out))
+ return 0;
+
+ bpf_map_update_elem(&devmap_xmit_cnt_multi, &idx, &empty, BPF_NOEXIST);
+ rec = bpf_map_lookup_elem(&devmap_xmit_cnt_multi, &idx);
+ if (!rec)
+ return 0;
+
+ NO_TEAR_ADD(rec->processed, sent);
+ NO_TEAR_ADD(rec->dropped, drops);
+ NO_TEAR_INC(rec->info);
+ if (err || drops < 0)
+ NO_TEAR_INC(rec->issue);
+ return 0;
+}
diff --git a/samples/bpf/xdp_sample.bpf.h b/samples/bpf/xdp_sample.bpf.h
new file mode 100644
index 000000000000..20a7ae25167b
--- /dev/null
+++ b/samples/bpf/xdp_sample.bpf.h
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef _XDP_SAMPLE_BPF_H
+#define _XDP_SAMPLE_BPF_H
+
+#include "vmlinux.h"
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_helpers.h>
+
+#include "xdp_sample_shared.h"
+
+#define ETH_ALEN 6
+#define ETH_P_802_3_MIN 0x0600
+#define ETH_P_8021Q 0x8100
+#define ETH_P_8021AD 0x88A8
+#define ETH_P_IP 0x0800
+#define ETH_P_IPV6 0x86DD
+#define ETH_P_ARP 0x0806
+#define IPPROTO_ICMPV6 58
+
+#define EINVAL 22
+#define ENETDOWN 100
+#define EMSGSIZE 90
+#define EOPNOTSUPP 95
+#define ENOSPC 28
+
+extern struct sample_data sample_data;
+
+enum {
+ XDP_REDIRECT_SUCCESS = 0,
+ XDP_REDIRECT_ERROR = 1
+};
+
+static __always_inline void swap_src_dst_mac(void *data)
+{
+ unsigned short *p = data;
+ unsigned short dst[3];
+
+ dst[0] = p[0];
+ dst[1] = p[1];
+ dst[2] = p[2];
+ p[0] = p[3];
+ p[1] = p[4];
+ p[2] = p[5];
+ p[3] = dst[0];
+ p[4] = dst[1];
+ p[5] = dst[2];
+}
+
+#if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && \
+ __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#define bpf_ntohs(x) __builtin_bswap16(x)
+#define bpf_htons(x) __builtin_bswap16(x)
+#elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && \
+ __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#define bpf_ntohs(x) (x)
+#define bpf_htons(x) (x)
+#else
+# error "Endianness detection needs to be set up for your compiler?!"
+#endif
+
+#endif
--
2.32.0
