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/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <errno.h>
#include <linux/if_ether.h>
#include <linux/pfkeyv2.h>
#include <net/if.h>
#include <stdlib.h>
#include <string.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <sys/utsname.h>
#include <log/log.h>
#include "KernelUtils.h"
namespace android {
namespace bpf {
// See kernel's net/core/sock_diag.c __sock_gen_cookie()
// the implementation of which guarantees 0 will never be returned,
// primarily because 0 is used to mean not yet initialized,
// and socket cookies are only assigned on first fetch.
constexpr const uint64_t NONEXISTENT_COOKIE = 0;
static inline uint64_t getSocketCookie(int sockFd) {
uint64_t sock_cookie;
socklen_t cookie_len = sizeof(sock_cookie);
if (getsockopt(sockFd, SOL_SOCKET, SO_COOKIE, &sock_cookie, &cookie_len)) {
// Failure is almost certainly either EBADF or ENOTSOCK
const int err = errno;
ALOGE("Failed to get socket cookie: %s\n", strerror(err));
errno = err;
return NONEXISTENT_COOKIE;
}
if (cookie_len != sizeof(sock_cookie)) {
// This probably cannot actually happen, but...
ALOGE("Failed to get socket cookie: len %d != 8\n", cookie_len);
errno = 523; // EBADCOOKIE: kernel internal, seems reasonable enough...
return NONEXISTENT_COOKIE;
}
return sock_cookie;
}
static inline int synchronizeKernelRCU() {
// This is a temporary hack for network stats map swap on devices running
// 4.9 kernels. The kernel code of socket release on pf_key socket will
// explicitly call synchronize_rcu() which is exactly what we need.
//
// Linux 4.14/4.19/5.4/5.10/5.15/6.1 (and 6.3-rc5) still have this same behaviour.
// see net/key/af_key.c: pfkey_release() -> synchronize_rcu()
// https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/key/af_key.c?h=v6.3-rc5#n185
const int pfSocket = socket(AF_KEY, SOCK_RAW | SOCK_CLOEXEC, PF_KEY_V2);
if (pfSocket < 0) {
const int err = errno;
ALOGE("create PF_KEY socket failed: %s", strerror(err));
return -err;
}
// When closing socket, synchronize_rcu() gets called in sock_release().
if (close(pfSocket)) {
const int err = errno;
ALOGE("failed to close the PF_KEY socket: %s", strerror(err));
return -err;
}
return 0;
}
static inline int setrlimitForTest() {
// Set the memory rlimit for the test process if the default MEMLOCK rlimit is not enough.
struct rlimit limit = {
.rlim_cur = 1073741824, // 1 GiB
.rlim_max = 1073741824, // 1 GiB
};
const int res = setrlimit(RLIMIT_MEMLOCK, &limit);
if (res) ALOGE("Failed to set the default MEMLOCK rlimit: %s", strerror(errno));
return res;
}
} // namespace bpf
} // namespace android
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