Update bpf syscall decoding
Implement decoding of BPF_OBJ_PIN, BPF_OBJ_GET, BPF_PROG_ATTACH, and BPF_PROG_DETACH commands. * bpf.c: Include "xlat/bpf_attach_type.h". (bpf_obj_manage, bpf_prog_attach, bpf_prog_detach): New functions. (SYS_FUNC(bpf)): Use them. * configure.ac: Check for union bpf_attr.bpf_fd and union bpf_attr.attach_type. * xlat/bpf_attach_type.in: New file. * xlat/bpf_commands.in: Update list of BPF_* command constants. * xlat/bpf_map_types.in: Update list of BPF_MAP_TYPE_* constants. * xlat/bpf_prog_types.in: Update list of BPF_PROG_TYPE_* constants. * tests/bpf.c [HAVE_UNION_BPF_ATTR_BPF_FD] (obj_manage): New function. [HAVE_UNION_BPF_ATTR_ATTACH_TYPE] (prog_cgroup): Likewise. (main): Use them.
This commit is contained in:
Quentin Monnet
parent
fe871501ff
commit
0a8dd6a68c
95
bpf.c
95
bpf.c
@ -1,5 +1,6 @@
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/*
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* Copyright (c) 2015 Dmitry V. Levin <ldv@altlinux.org>
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* Copyright (c) 2017 Quentin Monnet <quentin.monnet@6wind.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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@ -35,6 +36,7 @@
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#include "xlat/bpf_map_types.h"
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#include "xlat/bpf_prog_types.h"
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#include "xlat/bpf_map_update_elem_flags.h"
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#include "xlat/bpf_attach_type.h"
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static int
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bpf_map_create(struct tcb *const tcp, const kernel_ulong_t addr,
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@ -177,6 +179,87 @@ bpf_prog_load(struct tcb *const tcp, const kernel_ulong_t addr,
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return RVAL_DECODED | RVAL_FD;
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}
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static int
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bpf_obj_manage(struct tcb *const tcp, const kernel_ulong_t addr,
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unsigned int size)
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{
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struct {
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uint64_t ATTRIBUTE_ALIGNED(8) pathname;
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uint32_t bpf_fd;
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} attr = {};
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if (!size) {
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printaddr(addr);
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return RVAL_DECODED | RVAL_FD;
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}
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if (size > sizeof(attr))
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size = sizeof(attr);
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if (umoven_or_printaddr(tcp, addr, size, &attr))
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return RVAL_DECODED | RVAL_FD;
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tprintf("{pathname=");
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printpath(tcp, attr.pathname);
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tprints(", bpf_fd=");
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printfd(tcp, attr.bpf_fd);
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tprintf("}");
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return RVAL_DECODED | RVAL_FD;
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}
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static int
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bpf_prog_attach(struct tcb *const tcp, const kernel_ulong_t addr,
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unsigned int size)
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{
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struct {
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uint32_t target_fd, attach_bpf_fd, attach_type;
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} attr = {};
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if (!size) {
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printaddr(addr);
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return RVAL_DECODED;
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}
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if (size > sizeof(attr))
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size = sizeof(attr);
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if (umoven_or_printaddr(tcp, addr, size, &attr))
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return RVAL_DECODED;
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tprintf("{target_fd=");
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printfd(tcp, attr.target_fd);
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tprintf(", attach_bpf_fd=");
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printfd(tcp, attr.attach_bpf_fd);
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tprintf(", attach_type=");
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printxval(bpf_attach_type, attr.attach_type, "BPF_???");
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tprintf("}");
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return RVAL_DECODED;
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}
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static int
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bpf_prog_detach(struct tcb *const tcp, const kernel_ulong_t addr,
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unsigned int size)
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{
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struct {
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uint32_t target_fd, attach_bpf_fd, attach_type;
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} attr = {};
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if (!size) {
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printaddr(addr);
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return RVAL_DECODED;
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}
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if (size > sizeof(attr))
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size = sizeof(attr);
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if (umoven_or_printaddr(tcp, addr, size, &attr))
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return RVAL_DECODED;
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tprintf("{target_fd=");
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printfd(tcp, attr.target_fd);
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tprintf(", attach_type=");
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printxval(bpf_attach_type, attr.attach_type, "BPF_???");
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tprintf("}");
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return RVAL_DECODED;
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}
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SYS_FUNC(bpf)
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{
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const unsigned int cmd = tcp->u_arg[0];
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@ -208,6 +291,18 @@ SYS_FUNC(bpf)
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case BPF_PROG_LOAD:
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rc = bpf_prog_load(tcp, addr, size);
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break;
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case BPF_OBJ_PIN:
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rc = bpf_obj_manage(tcp, addr, size);
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break;
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case BPF_OBJ_GET:
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rc = bpf_obj_manage(tcp, addr, size);
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break;
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case BPF_PROG_ATTACH:
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rc = bpf_prog_attach(tcp, addr, size);
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break;
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case BPF_PROG_DETACH:
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rc = bpf_prog_detach(tcp, addr, size);
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break;
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default:
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printaddr(addr);
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break;
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22
configure.ac
22
configure.ac
@ -424,6 +424,28 @@ AC_CHECK_HEADERS([linux/bpf.h], [
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AC_DEFINE(HAVE_UNION_BPF_ATTR_LOG_BUF, [1],
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[Define to 1 if union bpf_attr.log_buf initialization works])
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fi
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AC_CACHE_CHECK([whether union bpf_attr.bpf_fd initialization works],
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[st_cv_have_union_bpf_attr_bpf_fd],
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[AC_COMPILE_IFELSE(
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[AC_LANG_PROGRAM([[#include <linux/bpf.h>]],
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[[union bpf_attr a = { .bpf_fd = 0 };]])],
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[st_cv_have_union_bpf_attr_bpf_fd=yes],
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[st_cv_have_union_bpf_attr_bpf_fd=no])])
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if test $st_cv_have_union_bpf_attr_bpf_fd = yes; then
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AC_DEFINE(HAVE_UNION_BPF_ATTR_BPF_FD, [1],
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[Define to 1 if union bpf_attr.bpf_fd initialization works])
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fi
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AC_CACHE_CHECK([whether union bpf_attr.attach_type initialization works],
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[st_cv_have_union_bpf_attr_attach_type],
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[AC_COMPILE_IFELSE(
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[AC_LANG_PROGRAM([[#include <linux/bpf.h>]],
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[[union bpf_attr a = { .attach_type = 0 };]])],
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[st_cv_have_union_bpf_attr_attach_type=yes],
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[st_cv_have_union_bpf_attr_attach_type=no])])
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if test $st_cv_have_union_bpf_attr_attach_type = yes; then
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AC_DEFINE(HAVE_UNION_BPF_ATTR_ATTACH_TYPE, [1],
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[Define to 1 if union bpf_attr.attach_type initialization works])
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fi
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])
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AC_CHECK_TYPES([struct statfs], [
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65
tests/bpf.c
65
tests/bpf.c
@ -76,6 +76,39 @@ prog_load(void)
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return syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));
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}
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/*
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* bpf() syscall and its first six commands were introduced in Linux kernel
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* 3.18. Some additional commands were added afterwards, so we need to take
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* precautions to make sure the tests compile.
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*
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* BPF_OBJ_PIN and BPF_OBJ_GET commands appear in kernel 4.4.
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*/
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# ifdef HAVE_UNION_BPF_ATTR_BPF_FD
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static int
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obj_manage(int cmd)
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{
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union bpf_attr attr = {
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.pathname = (unsigned long) "/sys/fs/bpf/foo/bar",
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.bpf_fd = -1
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};
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return syscall(__NR_bpf, cmd, &attr, sizeof(attr));
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}
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# endif
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/* BPF_PROG_ATTACH and BPF_PROG_DETACH commands appear in kernel 4.10. */
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# ifdef HAVE_UNION_BPF_ATTR_ATTACH_TYPE
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static int
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prog_cgroup(int cmd)
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{
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union bpf_attr attr = {
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.target_fd = -1,
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.attach_bpf_fd = -1,
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.attach_type = 0
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};
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return syscall(__NR_bpf, cmd, &attr, sizeof(attr));
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}
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# endif
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int
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main(void)
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{
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@ -119,6 +152,38 @@ main(void)
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"kern_version=0\\}, %u\\) += -1 .*\n",
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insns, log_buf, (unsigned) sizeof(union bpf_attr));
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# ifdef HAVE_UNION_BPF_ATTR_BPF_FD
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if (!obj_manage(BPF_OBJ_PIN))
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perror_msg_and_skip("BPF_OBJ_PIN");
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printf("bpf\\(BPF_OBJ_PIN, "
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"\\{pathname=\"/sys/fs/bpf/foo/bar\", "
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"bpf_fd=-1\\}, %u\\) += -1 .*\n",
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(unsigned) sizeof(union bpf_attr));
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if (!obj_manage(BPF_OBJ_GET))
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perror_msg_and_skip("BPF_OBJ_GET");
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printf("bpf\\(BPF_OBJ_GET, "
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"\\{pathname=\"/sys/fs/bpf/foo/bar\", "
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"bpf_fd=-1\\}, %u\\) += -1 .*\n",
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(unsigned) sizeof(union bpf_attr));
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# endif
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# ifdef HAVE_UNION_BPF_ATTR_ATTACH_TYPE
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if (!prog_cgroup(BPF_PROG_ATTACH))
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perror_msg_and_skip("BPF_PROG_ATTACH");
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printf("bpf\\(BPF_PROG_ATTACH, "
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"{target_fd=-1, attach_bpf_fd=-1, "
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"attach_type=BPF_CGROUP_INET_INGRESS\\}, %u\\) += -1 .*\n",
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(unsigned) sizeof(union bpf_attr));
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if (!prog_cgroup(BPF_PROG_DETACH))
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perror_msg_and_skip("BPF_PROG_DETACH");
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printf("bpf\\(BPF_PROG_DETACH, "
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"\\{target_fd=-1, attach_type=BPF_CGROUP_INET_INGRESS\\}, "
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"%u\\) += -1 .*\n",
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(unsigned) sizeof(union bpf_attr));
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# endif
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return 0;
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}
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3
xlat/bpf_attach_type.in
Normal file
3
xlat/bpf_attach_type.in
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@ -0,0 +1,3 @@
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BPF_CGROUP_INET_INGRESS 0
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BPF_CGROUP_INET_EGRESS 1
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BPF_CGROUP_INET_SOCK_CREATE 2
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@ -4,3 +4,7 @@ BPF_MAP_UPDATE_ELEM 2
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BPF_MAP_DELETE_ELEM 3
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BPF_MAP_GET_NEXT_KEY 4
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BPF_PROG_LOAD 5
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BPF_OBJ_PIN 6
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BPF_OBJ_GET 7
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BPF_PROG_ATTACH 8
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BPF_PROG_DETACH 9
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@ -7,3 +7,6 @@ BPF_MAP_TYPE_PERCPU_HASH 5
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BPF_MAP_TYPE_PERCPU_ARRAY 6
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BPF_MAP_TYPE_STACK_TRACE 7
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BPF_MAP_TYPE_CGROUP_ARRAY 8
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BPF_MAP_TYPE_LRU_HASH 9
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BPF_MAP_TYPE_LRU_PERCPU_HASH 10
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BPF_MAP_TYPE_LPM_TRIE 11
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@ -6,3 +6,8 @@ BPF_PROG_TYPE_SCHED_ACT 4
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BPF_PROG_TYPE_TRACEPOINT 5
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BPF_PROG_TYPE_XDP 6
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BPF_PROG_TYPE_PERF_EVENT 7
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BPF_PROG_TYPE_CGROUP_SKB 8
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BPF_PROG_TYPE_CGROUP_SOCK 9
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BPF_PROG_TYPE_LWT_IN 10
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BPF_PROG_TYPE_LWT_OUT 11
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BPF_PROG_TYPE_LWT_XMIT 12
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