ed57b98758
This is just a subset of the recently-implemented getifaddrs(3), though if we want to handle interfaces (such as "rmnet_*") that don't have an address, we need to either expose ifaddrs_storage and keep track of which interfaces we've already seen (which is pretty messy), or refactor the netlink code so we can reuse it and just extract the information we need for if_nameindex(3). This patch goes the latter route. Also clean up if_nametoindex(3) and if_indextoname(3). Change-Id: I5ffc5df0bab62286cdda2e7af06f032c767119a8
93 lines
3.3 KiB
C++
93 lines
3.3 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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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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fd_ = socket(PF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE);
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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) return false;
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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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