6cb70ad776
This is actually for the new change I'm working on, but let's retrofit it first to separate any bugs in these changes from those in the new change... Test: treehugger Change-Id: I890aeb61f9792810a77ad0da3f9674c9cc5db7bb
94 lines
3.5 KiB
C++
94 lines
3.5 KiB
C++
/*
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* Copyright (C) 2015 The Android Open Source Project
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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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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "bionic_netlink.h"
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#include <errno.h>
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#include <linux/netlink.h>
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#include <linux/rtnetlink.h>
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#include <string.h>
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#include <stdlib.h>
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#include <sys/socket.h>
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#include <unistd.h>
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#include "private/ErrnoRestorer.h"
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NetlinkConnection::NetlinkConnection() {
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// The kernel keeps packets under 8KiB (NLMSG_GOODSIZE),
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// but that's a bit too large to go on the stack.
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size_ = 8192;
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data_ = new char[size_];
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}
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NetlinkConnection::~NetlinkConnection() {
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delete[] data_;
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}
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bool NetlinkConnection::SendRequest(int type) {
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// Rather than force all callers to check for the unlikely event of being
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// unable to allocate 8KiB, check here.
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if (data_ == nullptr) return false;
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// Did we open a netlink socket yet?
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if (fd_.get() == -1) {
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fd_.reset(socket(PF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE));
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if (fd_.get() == -1) return false;
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}
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// Construct and send the message.
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struct NetlinkMessage {
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nlmsghdr hdr;
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rtgenmsg msg;
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} request;
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memset(&request, 0, sizeof(request));
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request.hdr.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST;
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request.hdr.nlmsg_type = type;
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request.hdr.nlmsg_len = sizeof(request);
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request.msg.rtgen_family = AF_UNSPEC; // All families.
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return (TEMP_FAILURE_RETRY(send(fd_.get(), &request, sizeof(request), 0)) == sizeof(request));
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}
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bool NetlinkConnection::ReadResponses(void callback(void*, nlmsghdr*), void* context) {
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// Read through all the responses, handing interesting ones to the callback.
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ssize_t bytes_read;
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while ((bytes_read = TEMP_FAILURE_RETRY(recv(fd_.get(), data_, size_, 0))) > 0) {
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nlmsghdr* hdr = reinterpret_cast<nlmsghdr*>(data_);
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for (; NLMSG_OK(hdr, static_cast<size_t>(bytes_read)); hdr = NLMSG_NEXT(hdr, bytes_read)) {
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if (hdr->nlmsg_type == NLMSG_DONE) return true;
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if (hdr->nlmsg_type == NLMSG_ERROR) {
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nlmsgerr* err = reinterpret_cast<nlmsgerr*>(NLMSG_DATA(hdr));
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errno = (hdr->nlmsg_len >= NLMSG_LENGTH(sizeof(nlmsgerr))) ? -err->error : EIO;
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return false;
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}
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callback(context, hdr);
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}
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}
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// We only get here if recv fails before we see a NLMSG_DONE.
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return false;
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}
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