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106 lines
3.6 KiB
106 lines
3.6 KiB
/* |
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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/types.h> |
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#include <sys/socket.h> |
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#include <unistd.h> |
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#include <sys/stat.h> |
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#include <fcntl.h> |
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#include "ErrnoRestorer.h" |
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NetlinkConnection::NetlinkConnection() { |
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fd_ = -1; |
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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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ErrnoRestorer errno_restorer; |
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if (fd_ != -1) close(fd_); |
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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_ == -1) { |
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#ifndef SOCK_CLOEXEC |
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#define SOCK_CLOEXEC O_CLOEXEC |
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#endif |
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fd_ = socket(PF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE); |
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if (fd_ == -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_, &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_, 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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