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>

Author: Jakub Kicinski

samples/bpf/.gitignore

@@ -1,7 +1,6 @@
 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

@@ -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_basertt_kern.c

@@ -8,19 +8,21 @@ 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
 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_bpf.readme

@@ -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_bufs_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_clamp_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_cong_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_iw_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>