From ae16189efb0fe2bdc5e702bd6221ed6d0ff5babd Mon Sep 17 00:00:00 2001 From: Lawrence Brakmo Date: Fri, 30 Jun 2017 20:02:41 -0700 Subject: 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] 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 Detaches the currently attached sock_ops program from the specified cgroup. Signed-off-by: Lawrence Brakmo Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- samples/bpf/Makefile | 3 ++ samples/bpf/load_sock_ops.c | 97 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 100 insertions(+) create mode 100644 samples/bpf/load_sock_ops.c (limited to 'samples') diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index e7ec9b8..015589b 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -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 diff --git a/samples/bpf/load_sock_ops.c b/samples/bpf/load_sock_ops.c new file mode 100644 index 0000000..e5da6cf --- /dev/null +++ b/samples/bpf/load_sock_ops.c @@ -0,0 +1,97 @@ +/* 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 +#include +#include +#include +#include "libbpf.h" +#include "bpf_load.h" +#include +#include +#include +#include + +static void usage(char *pname) +{ + printf("USAGE:\n %s [-l] \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 \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; +} -- cgit v1.1