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// Copyright 2018 The gVisor Authors.
//
// 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.
#include "test/syscalls/linux/socket_netlink_util.h"
#include <linux/if_arp.h>
#include <linux/netlink.h>
#include <sys/socket.h>
#include <vector>
#include "absl/strings/str_cat.h"
#include "test/syscalls/linux/socket_test_util.h"
namespace gvisor {
namespace testing {
PosixErrorOr<FileDescriptor> NetlinkBoundSocket(int protocol) {
FileDescriptor fd;
ASSIGN_OR_RETURN_ERRNO(fd, Socket(AF_NETLINK, SOCK_RAW, protocol));
struct sockaddr_nl addr = {};
addr.nl_family = AF_NETLINK;
RETURN_ERROR_IF_SYSCALL_FAIL(
bind(fd.get(), reinterpret_cast<struct sockaddr*>(&addr), sizeof(addr)));
MaybeSave();
return std::move(fd);
}
PosixErrorOr<uint32> NetlinkPortID(int fd) {
struct sockaddr_nl addr;
socklen_t addrlen = sizeof(addr);
RETURN_ERROR_IF_SYSCALL_FAIL(
getsockname(fd, reinterpret_cast<struct sockaddr*>(&addr), &addrlen));
MaybeSave();
return static_cast<uint32>(addr.nl_pid);
}
PosixError NetlinkRequestResponse(
const FileDescriptor& fd, void* request, size_t len,
const std::function<void(const struct nlmsghdr* hdr)>& fn,
bool expect_nlmsgerr) {
struct iovec iov = {};
iov.iov_base = request;
iov.iov_len = len;
struct msghdr msg = {};
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
// No destination required; it defaults to pid 0, the kernel.
RETURN_ERROR_IF_SYSCALL_FAIL(RetryEINTR(sendmsg)(fd.get(), &msg, 0));
constexpr size_t kBufferSize = 4096;
std::vector<char> buf(kBufferSize);
iov.iov_base = buf.data();
iov.iov_len = buf.size();
// Response is a series of NLM_F_MULTI messages, ending with a NLMSG_DONE
// message.
int type = -1;
do {
int len;
RETURN_ERROR_IF_SYSCALL_FAIL(len = RetryEINTR(recvmsg)(fd.get(), &msg, 0));
// We don't bother with the complexity of dealing with truncated messages.
// We must allocate a large enough buffer up front.
if ((msg.msg_flags & MSG_TRUNC) == MSG_TRUNC) {
return PosixError(EIO,
absl::StrCat("Received truncated message with flags: ",
msg.msg_flags));
}
for (struct nlmsghdr* hdr = reinterpret_cast<struct nlmsghdr*>(buf.data());
NLMSG_OK(hdr, len); hdr = NLMSG_NEXT(hdr, len)) {
fn(hdr);
type = hdr->nlmsg_type;
// Done should include an integer payload for dump_done_errno.
// See net/netlink/af_netlink.c:netlink_dump
// Some tools like the 'ip' tool check the minimum length of the
// NLMSG_DONE message.
if (type == NLMSG_DONE) {
EXPECT_GE(hdr->nlmsg_len, NLMSG_LENGTH(sizeof(int)));
}
}
} while (type != NLMSG_DONE && type != NLMSG_ERROR);
if (expect_nlmsgerr) {
EXPECT_EQ(type, NLMSG_ERROR);
} else {
EXPECT_EQ(type, NLMSG_DONE);
}
return NoError();
}
} // namespace testing
} // namespace gvisor
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