samples: bpf: remove load_sock_ops in favour of bpftool

bpftool can do all the things load_sock_ops used to do, and more.
Point users to bpftool instead of maintaining this sample utility.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

samples/bpf/.gitignore

 cpustat
 fds_example
 lathist
-load_sock_ops
 lwt_len_hist
 map_perf_test
 offwaketime

samples/bpf/Makefile

@@ -40,7 +40,6 @@ hostprogs-y += lwt_len_hist
 hostprogs-y += xdp_tx_iptunnel
 hostprogs-y += test_map_in_map
 hostprogs-y += per_socket_stats_example
-hostprogs-y += load_sock_ops
 hostprogs-y += xdp_redirect
 hostprogs-y += xdp_redirect_map
 hostprogs-y += xdp_redirect_cpu
@@ -71,7 +70,6 @@ tracex4-objs := bpf_load.o tracex4_user.o
 tracex5-objs := bpf_load.o tracex5_user.o
 tracex6-objs := bpf_load.o tracex6_user.o
 tracex7-objs := bpf_load.o tracex7_user.o
-load_sock_ops-objs := bpf_load.o load_sock_ops.o
 test_probe_write_user-objs := bpf_load.o test_probe_write_user_user.o
 trace_output-objs := bpf_load.o trace_output_user.o $(TRACE_HELPERS)
 lathist-objs := bpf_load.o lathist_user.o

samples/bpf/load_sock_ops.c

-/* Copyright (c) 2017 Facebook
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- */
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <linux/bpf.h>
-#include <bpf/bpf.h>
-#include "bpf_load.h"
-#include <unistd.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <linux/unistd.h>
-
-static void usage(char *pname)
-{
-	printf("USAGE:\n  %s [-l] <cg-path> <prog filename>\n", pname);
-	printf("\tLoad and attach a sock_ops program to the specified "
-	       "cgroup\n");
-	printf("\tIf \"-l\" is used, the program will continue to run\n");
-	printf("\tprinting the BPF log buffer\n");
-	printf("\tIf the specified filename does not end in \".o\", it\n");
-	printf("\tappends \"_kern.o\" to the name\n");
-	printf("\n");
-	printf("  %s -r <cg-path>\n", pname);
-	printf("\tDetaches the currently attached sock_ops program\n");
-	printf("\tfrom the specified cgroup\n");
-	printf("\n");
-	exit(1);
-}
-
-int main(int argc, char **argv)
-{
-	int logFlag = 0;
-	int error = 0;
-	char *cg_path;
-	char fn[500];
-	char *prog;
-	int cg_fd;
-
-	if (argc < 3)
-		usage(argv[0]);
-
-	if (!strcmp(argv[1], "-r")) {
-		cg_path = argv[2];
-		cg_fd = open(cg_path, O_DIRECTORY, O_RDONLY);
-		error = bpf_prog_detach(cg_fd, BPF_CGROUP_SOCK_OPS);
-		if (error) {
-			printf("ERROR: bpf_prog_detach: %d (%s)\n",
-			       error, strerror(errno));
-			return 2;
-		}
-		return 0;
-	} else if (!strcmp(argv[1], "-h")) {
-		usage(argv[0]);
-	} else if (!strcmp(argv[1], "-l")) {
-		logFlag = 1;
-		if (argc < 4)
-			usage(argv[0]);
-	}
-
-	prog = argv[argc - 1];
-	cg_path = argv[argc - 2];
-	if (strlen(prog) > 480) {
-		fprintf(stderr, "ERROR: program name too long (> 480 chars)\n");
-		return 3;
-	}
-	cg_fd = open(cg_path, O_DIRECTORY, O_RDONLY);
-
-	if (!strcmp(prog + strlen(prog)-2, ".o"))
-		strcpy(fn, prog);
-	else
-		sprintf(fn, "%s_kern.o", prog);
-	if (logFlag)
-		printf("loading bpf file:%s\n", fn);
-	if (load_bpf_file(fn)) {
-		printf("ERROR: load_bpf_file failed for: %s\n", fn);
-		printf("%s", bpf_log_buf);
-		return 4;
-	}
-	if (logFlag)
-		printf("TCP BPF Loaded %s\n", fn);
-
-	error = bpf_prog_attach(prog_fd[0], cg_fd, BPF_CGROUP_SOCK_OPS, 0);
-	if (error) {
-		printf("ERROR: bpf_prog_attach: %d (%s)\n",
-		       error, strerror(errno));
-		return 5;
-	} else if (logFlag) {
-		read_trace_pipe();
-	}
-
-	return error;
-}

samples/bpf/tcp_basertt_kern.c

@@ -7,7 +7,7 @@
  * BPF program to set base_rtt to 80us when host is running TCP-NV and
  * both hosts are in the same datacenter (as determined by IPv6 prefix).
  *
- * Use load_sock_ops to load this BPF program.
+ * Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program.
  */
 
 #include <uapi/linux/bpf.h>

samples/bpf/tcp_bpf.readme

@@ -8,14 +8,16 @@ a cgroupv2 and attach a bash shell to the group.
   bash
   echo $$ >> /tmp/cgroupv2/foo/cgroup.procs
 
-Anything that runs under this shell belongs to the foo cgroupv2 To load
+Anything that runs under this shell belongs to the foo cgroupv2. To load
 (attach) one of the tcp_*_kern.o programs:
 
-  ./load_sock_ops -l /tmp/cgroupv2/foo tcp_basertt_kern.o
+  bpftool prog load tcp_basertt_kern.o /sys/fs/bpf/tcp_prog
+  bpftool cgroup attach /tmp/cgroupv2/foo sock_ops pinned /sys/fs/bpf/tcp_prog
+  bpftool prog tracelog
 
-If the "-l" flag is used, the load_sock_ops program will continue to run
-printing the BPF log buffer. The tcp_*_kern.o programs use special print
-functions to print logging information (if enabled by the ifdef).
+"bpftool prog tracelog" will continue to run printing the BPF log buffer.
+The tcp_*_kern.o programs use special print functions to print logging
+information (if enabled by the ifdef).
 
 If using netperf/netserver to create traffic, you need to run them under the
 cgroupv2 to which the BPF programs are attached (i.e. under bash shell
@@ -23,4 +25,4 @@ attached to the cgroupv2).
 
 To remove (unattach) a socket_ops BPF program from a cgroupv2:
 
-  ./load_sock_ops -r /tmp/cgroupv2/foo
+  bpftool cgroup attach /tmp/cgroupv2/foo sock_ops pinned /sys/fs/bpf/tcp_prog

samples/bpf/tcp_bufs_kern.c

@@ -9,7 +9,7 @@
  * doing appropriate checks that indicate the hosts are far enough
  * away (i.e. large RTT).
  *
- * Use load_sock_ops to load this BPF program.
+ * Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program.
  */
 
 #include <uapi/linux/bpf.h>

samples/bpf/tcp_clamp_kern.c

@@ -9,7 +9,7 @@
  * the same datacenter. For his example, we assume they are within the same
  * datacenter when the first 5.5 bytes of their IPv6 addresses are the same.
  *
- * Use load_sock_ops to load this BPF program.
+ * Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program.
  */
 
 #include <uapi/linux/bpf.h>

samples/bpf/tcp_cong_kern.c

@@ -7,7 +7,7 @@
  * BPF program to set congestion control to dctcp when both hosts are
  * in the same datacenter (as deteremined by IPv6 prefix).
  *
- * Use load_sock_ops to load this BPF program.
+ * Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program.
  */
 
 #include <uapi/linux/bpf.h>

samples/bpf/tcp_iw_kern.c

@@ -9,7 +9,7 @@
  * would usually be done after doing appropriate checks that indicate
  * the hosts are far enough away (i.e. large RTT).
  *
- * Use load_sock_ops to load this BPF program.
+ * Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program.
  */
 
 #include <uapi/linux/bpf.h>

samples/bpf/tcp_rwnd_kern.c

@@ -8,7 +8,7 @@
  * and the first 5.5 bytes of the IPv6 addresses are not the same (in this
  * example that means both hosts are not the same datacenter).
  *
- * Use load_sock_ops to load this BPF program.
+ * Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program.
  */
 
 #include <uapi/linux/bpf.h>

samples/bpf/tcp_synrto_kern.c

@@ -8,7 +8,7 @@
  * and the first 5.5 bytes of the IPv6 addresses are the same (in this example
  * that means both hosts are in the same datacenter).
  *
- * Use load_sock_ops to load this BPF program.
+ * Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program.
  */
 
 #include <uapi/linux/bpf.h>

samples/bpf/tcp_tos_reflect_kern.c

@@ -4,7 +4,7 @@
  *
  * BPF program to automatically reflect TOS option from received syn packet
  *
- * Use load_sock_ops to load this BPF program.
+ * Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program.
  */
 
 #include <uapi/linux/bpf.h>