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Commit ae16189e authored by Lawrence Brakmo's avatar Lawrence Brakmo Committed by David S. Miller
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bpf: program to load and attach sock_ops BPF progs 



The program load_sock_ops can be used to load sock_ops bpf programs and
to attach it to an existing (v2) cgroup. It can also be used to detach
sock_ops programs.

Examples:
    load_sock_ops [-l] <cg-path> <prog filename>
	Load and attaches a sock_ops program at the specified cgroup.
	If "-l" is used, the program will continue to run to output the
	BPF log buffer.
	If the specified filename does not end in ".o", it appends
	"_kern.o" to the name.

    load_sock_ops -r <cg-path>
	Detaches the currently attached sock_ops program from the
	specified cgroup.

Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 40304b2a

samples/bpf/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ 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



# Libbpf dependencies

LIBBPF := ../../tools/lib/bpf/bpf.o
@@ -52,6 +53,7 @@ tracex3-objs := bpf_load.o $(LIBBPF) tracex3_user.o 
tracex4-objs := bpf_load.o $(LIBBPF) tracex4_user.o

tracex5-objs := bpf_load.o $(LIBBPF) tracex5_user.o

tracex6-objs := bpf_load.o $(LIBBPF) tracex6_user.o

load_sock_ops-objs := bpf_load.o $(LIBBPF) load_sock_ops.o

test_probe_write_user-objs := bpf_load.o $(LIBBPF) test_probe_write_user_user.o

trace_output-objs := bpf_load.o $(LIBBPF) trace_output_user.o

lathist-objs := bpf_load.o $(LIBBPF) lathist_user.o
@@ -130,6 +132,7 @@ HOSTLOADLIBES_tracex4 += -lelf -lrt 
HOSTLOADLIBES_tracex5 += -lelf

HOSTLOADLIBES_tracex6 += -lelf

HOSTLOADLIBES_test_cgrp2_sock2 += -lelf

HOSTLOADLIBES_load_sock_ops += -lelf

HOSTLOADLIBES_test_probe_write_user += -lelf

HOSTLOADLIBES_trace_output += -lelf -lrt

HOSTLOADLIBES_lathist += -lelf

samples/bpf/load_sock_ops.c

0 → 100644
+97 −0
Original line number Diff line number Diff line 
/* 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 "libbpf.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;

}