examples: generate types via bpf2go

examples/fentry/fentry.c

@@ -1,6 +1,8 @@
 // +build ignore
 
 #include "common.h"
+
+#include "bpf_endian.h"
 #include "bpf_helpers.h"
 #include "bpf_tracing.h"
 
@@ -38,8 +40,11 @@ struct {
 	__uint(max_entries, 1 << 24);
 } events SEC(".maps");
 
-struct event_t {
-	char comm[16];
+// Force emitting struct event into the ELF.
+const struct event *unused __attribute__((unused));
+
+struct event {
+	u8 comm[16];
 	__u16 sport;
 	__be16 dport;
 	__be32 saddr;
@@ -52,16 +57,16 @@ int BPF_PROG(tcp_connect, struct sock *sk) {
 		return 0;
 	}
 
-	struct event_t *tcp_info;
-	tcp_info = bpf_ringbuf_reserve(&events, sizeof(struct event_t), 0);
+	struct event *tcp_info;
+	tcp_info = bpf_ringbuf_reserve(&events, sizeof(struct event), 0);
 	if (!tcp_info) {
 		return 0;
 	}
 
 	tcp_info->saddr = sk->__sk_common.skc_rcv_saddr;
 	tcp_info->daddr = sk->__sk_common.skc_daddr;
 	tcp_info->dport = sk->__sk_common.skc_dport;
-	tcp_info->sport = sk->__sk_common.skc_num;
+	tcp_info->sport = bpf_htons(sk->__sk_common.skc_num);
 
 	bpf_get_current_comm(&tcp_info->comm, TASK_COMM_LEN);
 

examples/fentry/main.go

@@ -17,52 +17,22 @@
 package main
 
 import (
+	"bytes"
 	"encoding/binary"
 	"errors"
-	"fmt"
 	"log"
 	"net"
 	"os"
 	"os/signal"
 	"syscall"
 
-	"github.com/cilium/ebpf/internal"
-	"github.com/cilium/ebpf/internal/unix"
 	"github.com/cilium/ebpf/link"
 	"github.com/cilium/ebpf/ringbuf"
 	"github.com/cilium/ebpf/rlimit"
 )
 
 // $BPF_CLANG and $BPF_CFLAGS are set by the Makefile.
-//go:generate go run github.com/cilium/ebpf/cmd/bpf2go -cc $BPF_CLANG -cflags $BPF_CFLAGS bpf fentry.c -- -I../headers
-
-// Length of struct event_t sent from kernelspace.
-var eventLength = 28
-
-type Event struct {
-	Comm  string
-	SPort uint16
-	DPort uint16
-	SAddr uint32
-	DAddr uint32
-}
-
-// UnmarshalBinary unmarshals a ringbuf record into an Event.
-func (e *Event) UnmarshalBinary(b []byte) error {
-	if len(b) != eventLength {
-		return fmt.Errorf("unexpected event length %d", len(b))
-	}
-
-	e.Comm = unix.ByteSliceToString(b[:16])
-
-	e.SPort = internal.NativeEndian.Uint16(b[16:18])
-	e.DPort = binary.BigEndian.Uint16(b[18:20])
-
-	e.SAddr = binary.BigEndian.Uint32(b[20:24])
-	e.DAddr = binary.BigEndian.Uint32(b[24:28])
-
-	return nil
-}
+//go:generate go run github.com/cilium/ebpf/cmd/bpf2go -cc $BPF_CLANG -cflags $BPF_CFLAGS -type event bpf fentry.c -- -I../headers
 
 func main() {
 	stopper := make(chan os.Signal, 1)
@@ -110,7 +80,8 @@ func main() {
 		"Port",
 	)
 
-	var event Event
+	// bpfEvent is generated by bpf2go.
+	var event bpfEvent
 	for {
 		record, err := rd.Read()
 		if err != nil {
@@ -122,17 +93,18 @@ func main() {
 			continue
 		}
 
-		// Parse the ringbuf event entry into an Event structure.
-		if err := event.UnmarshalBinary(record.RawSample); err != nil {
-			log.Fatal("unmarshaling event: %s", err)
+		// Parse the ringbuf event entry into a bpfEvent structure.
+		if err := binary.Read(bytes.NewBuffer(record.RawSample), binary.BigEndian, &event); err != nil {
+			log.Printf("parsing ringbuf event: %s", err)
+			continue
 		}
 
 		log.Printf("%-16s %-15s %-6d -> %-15s %-6d",
 			event.Comm,
-			intToIP(event.SAddr),
-			event.SPort,
-			intToIP(event.DAddr),
-			event.DPort,
+			intToIP(event.Saddr),
+			event.Sport,
+			intToIP(event.Daddr),
+			event.Dport,
 		)
 	}
 }

examples/go.mod

@@ -3,6 +3,6 @@ module github.com/cilium/ebpf/examples
 go 1.16
 
 require (
-	github.com/cilium/ebpf v0.7.1-0.20211126075831-9ead52e53c13
+	github.com/cilium/ebpf v0.8.2-0.20220217141816-62da0a730ab7
 	golang.org/x/sys v0.0.0-20211001092434-39dca1131b70
 )

examples/go.sum

@@ -1,5 +1,5 @@
-github.com/cilium/ebpf v0.7.1-0.20211126075831-9ead52e53c13 h1:VrGaFU0ySWPDWlVQ7upRMX16MmU/hr6zw3Hia2HHmFM=
-github.com/cilium/ebpf v0.7.1-0.20211126075831-9ead52e53c13/go.mod h1:f5zLIM0FSNuAkSyLAN7X+Hy6yznlF1mNiWUMfxMtrgk=
+github.com/cilium/ebpf v0.8.2-0.20220217141816-62da0a730ab7 h1:E9LSbo1EEbVIJ9w49myVxWmneomxCc2L7orPVXt0HeY=
+github.com/cilium/ebpf v0.8.2-0.20220217141816-62da0a730ab7/go.mod h1:f5zLIM0FSNuAkSyLAN7X+Hy6yznlF1mNiWUMfxMtrgk=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/frankban/quicktest v1.14.0 h1:+cqqvzZV87b4adx/5ayVOaYZ2CrvM4ejQvUdBzPPUss=
 github.com/frankban/quicktest v1.14.0/go.mod h1:NeW+ay9A/U67EYXNFA1nPE8e/tnQv/09mUdL/ijj8og=

examples/headers/LICENSE.BSD-2-Clause

@@ -0,0 +1,32 @@
+Valid-License-Identifier: BSD-2-Clause
+SPDX-URL: https://spdx.org/licenses/BSD-2-Clause.html
+Usage-Guide:
+  To use the BSD 2-clause "Simplified" License put the following SPDX
+  tag/value pair into a comment according to the placement guidelines in
+  the licensing rules documentation:
+    SPDX-License-Identifier: BSD-2-Clause
+License-Text:
+
+Copyright (c) <year> <owner> . All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.

examples/headers/bpf_endian.h

@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+#ifndef __BPF_ENDIAN__
+#define __BPF_ENDIAN__
+
+/*
+ * Isolate byte #n and put it into byte #m, for __u##b type.
+ * E.g., moving byte #6 (nnnnnnnn) into byte #1 (mmmmmmmm) for __u64:
+ * 1) xxxxxxxx nnnnnnnn xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx mmmmmmmm xxxxxxxx
+ * 2) nnnnnnnn xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx mmmmmmmm xxxxxxxx 00000000
+ * 3) 00000000 00000000 00000000 00000000 00000000 00000000 00000000 nnnnnnnn
+ * 4) 00000000 00000000 00000000 00000000 00000000 00000000 nnnnnnnn 00000000
+ */
+#define ___bpf_mvb(x, b, n, m) ((__u##b)(x) << (b-(n+1)*8) >> (b-8) << (m*8))
+
+#define ___bpf_swab16(x) ((__u16)(			\
+			  ___bpf_mvb(x, 16, 0, 1) |	\
+			  ___bpf_mvb(x, 16, 1, 0)))
+
+#define ___bpf_swab32(x) ((__u32)(			\
+			  ___bpf_mvb(x, 32, 0, 3) |	\
+			  ___bpf_mvb(x, 32, 1, 2) |	\
+			  ___bpf_mvb(x, 32, 2, 1) |	\
+			  ___bpf_mvb(x, 32, 3, 0)))
+
+#define ___bpf_swab64(x) ((__u64)(			\
+			  ___bpf_mvb(x, 64, 0, 7) |	\
+			  ___bpf_mvb(x, 64, 1, 6) |	\
+			  ___bpf_mvb(x, 64, 2, 5) |	\
+			  ___bpf_mvb(x, 64, 3, 4) |	\
+			  ___bpf_mvb(x, 64, 4, 3) |	\
+			  ___bpf_mvb(x, 64, 5, 2) |	\
+			  ___bpf_mvb(x, 64, 6, 1) |	\
+			  ___bpf_mvb(x, 64, 7, 0)))
+
+/* LLVM's BPF target selects the endianness of the CPU
+ * it compiles on, or the user specifies (bpfel/bpfeb),
+ * respectively. The used __BYTE_ORDER__ is defined by
+ * the compiler, we cannot rely on __BYTE_ORDER from
+ * libc headers, since it doesn't reflect the actual
+ * requested byte order.
+ *
+ * Note, LLVM's BPF target has different __builtin_bswapX()
+ * semantics. It does map to BPF_ALU | BPF_END | BPF_TO_BE
+ * in bpfel and bpfeb case, which means below, that we map
+ * to cpu_to_be16(). We could use it unconditionally in BPF
+ * case, but better not rely on it, so that this header here
+ * can be used from application and BPF program side, which
+ * use different targets.
+ */
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+# define __bpf_ntohs(x)			__builtin_bswap16(x)
+# define __bpf_htons(x)			__builtin_bswap16(x)
+# define __bpf_constant_ntohs(x)	___bpf_swab16(x)
+# define __bpf_constant_htons(x)	___bpf_swab16(x)
+# define __bpf_ntohl(x)			__builtin_bswap32(x)
+# define __bpf_htonl(x)			__builtin_bswap32(x)
+# define __bpf_constant_ntohl(x)	___bpf_swab32(x)
+# define __bpf_constant_htonl(x)	___bpf_swab32(x)
+# define __bpf_be64_to_cpu(x)		__builtin_bswap64(x)
+# define __bpf_cpu_to_be64(x)		__builtin_bswap64(x)
+# define __bpf_constant_be64_to_cpu(x)	___bpf_swab64(x)
+# define __bpf_constant_cpu_to_be64(x)	___bpf_swab64(x)
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+# define __bpf_ntohs(x)			(x)
+# define __bpf_htons(x)			(x)
+# define __bpf_constant_ntohs(x)	(x)
+# define __bpf_constant_htons(x)	(x)
+# define __bpf_ntohl(x)			(x)
+# define __bpf_htonl(x)			(x)
+# define __bpf_constant_ntohl(x)	(x)
+# define __bpf_constant_htonl(x)	(x)
+# define __bpf_be64_to_cpu(x)		(x)
+# define __bpf_cpu_to_be64(x)		(x)
+# define __bpf_constant_be64_to_cpu(x)  (x)
+# define __bpf_constant_cpu_to_be64(x)  (x)
+#else
+# error "Fix your compiler's __BYTE_ORDER__?!"
+#endif
+
+#define bpf_htons(x)				\
+	(__builtin_constant_p(x) ?		\
+	 __bpf_constant_htons(x) : __bpf_htons(x))
+#define bpf_ntohs(x)				\
+	(__builtin_constant_p(x) ?		\
+	 __bpf_constant_ntohs(x) : __bpf_ntohs(x))
+#define bpf_htonl(x)				\
+	(__builtin_constant_p(x) ?		\
+	 __bpf_constant_htonl(x) : __bpf_htonl(x))
+#define bpf_ntohl(x)				\
+	(__builtin_constant_p(x) ?		\
+	 __bpf_constant_ntohl(x) : __bpf_ntohl(x))
+#define bpf_cpu_to_be64(x)			\
+	(__builtin_constant_p(x) ?		\
+	 __bpf_constant_cpu_to_be64(x) : __bpf_cpu_to_be64(x))
+#define bpf_be64_to_cpu(x)			\
+	(__builtin_constant_p(x) ?		\
+	 __bpf_constant_be64_to_cpu(x) : __bpf_be64_to_cpu(x))
+
+#endif /* __BPF_ENDIAN__ */