Home | History | Annotate | Download | only in net 
      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 #include "common/libs/net/netlink_request.h"
     17 
     18 #include <linux/netlink.h>
     19 #include <linux/rtnetlink.h>
     20 #include <net/if.h>
     21 #include <string.h>
     22 
     23 #include <string>
     24 #include <vector>
     25 
     26 #include "common/libs/glog/logging.h"
     27 
     28 namespace cvd {
     29 namespace {
     30 uint32_t kRequestSequenceNumber = 0;
     31 }  // namespace
     32 
     33 uint32_t NetlinkRequest::SeqNo() const {
     34   return header_->nlmsg_seq;
     35 }
     36 
     37 void* NetlinkRequest::AppendRaw(const void* data, size_t length) {
     38   void* out = request_.end();
     39 
     40   request_.Append(data, length);
     41   int pad = RTA_ALIGN(length) - length;
     42   if (pad > 0) {
     43     request_.Resize(request_.size() + pad);
     44   }
     45 
     46   return out;
     47 }
     48 
     49 void* NetlinkRequest::ReserveRaw(size_t length) {
     50   void* out = request_.end();
     51   request_.Resize(request_.size() + RTA_ALIGN(length));
     52   return out;
     53 }
     54 
     55 nlattr* NetlinkRequest::AppendTag(
     56     uint16_t type, const void* data, uint16_t data_length) {
     57   nlattr* attr = Reserve<nlattr>();
     58   attr->nla_type = type;
     59   attr->nla_len = RTA_LENGTH(data_length);
     60   AppendRaw(data, data_length);
     61   return attr;
     62 }
     63 
     64 NetlinkRequest::NetlinkRequest(int32_t command, int32_t flags)
     65     : request_(512),
     66       header_(Reserve<nlmsghdr>()) {
     67   flags |= NLM_F_ACK | NLM_F_REQUEST;
     68   header_->nlmsg_flags = flags;
     69   header_->nlmsg_type = command;
     70   header_->nlmsg_pid = getpid();
     71   header_->nlmsg_seq = kRequestSequenceNumber++;
     72 }
     73 
     74 NetlinkRequest::NetlinkRequest(NetlinkRequest&& other) {
     75   using std::swap;
     76   swap(lists_, other.lists_);
     77   swap(header_, other.header_);
     78   request_.Swap(other.request_);
     79 }
     80 
     81 void NetlinkRequest::AddString(uint16_t type, const std::string& value) {
     82   AppendTag(type, value.c_str(), value.length() + 1);
     83 }
     84 
     85 void NetlinkRequest::AddInt32(uint16_t type, int32_t value) {
     86   AppendTag(type, &value, sizeof(value));
     87 }
     88 
     89 void NetlinkRequest::AddInt8(uint16_t type, int8_t value) {
     90   AppendTag(type, &value, sizeof(value));
     91 }
     92 
     93 void NetlinkRequest::AddIfInfo(int32_t if_index, bool operational) {
     94   ifinfomsg* if_info = Reserve<ifinfomsg>();
     95   if_info->ifi_family = AF_UNSPEC;
     96   if_info->ifi_index = if_index;
     97   if_info->ifi_flags = operational ? IFF_UP : 0;
     98   if_info->ifi_change = IFF_UP;
     99 }
    100 
    101 void NetlinkRequest::AddAddrInfo(int32_t if_index, int prefix_len) {
    102   ifaddrmsg* ad_info = Reserve<ifaddrmsg>();
    103   ad_info->ifa_family = AF_INET;
    104   ad_info->ifa_prefixlen = prefix_len;
    105   ad_info->ifa_flags = IFA_F_PERMANENT | IFA_F_SECONDARY;
    106   ad_info->ifa_scope = 0;
    107   ad_info->ifa_index = if_index;
    108 }
    109 
    110 void NetlinkRequest::PushList(uint16_t type) {
    111   int length = request_.size();
    112   nlattr* list = AppendTag(type, NULL, 0);
    113   lists_.push_back(std::make_pair(list, length));
    114 }
    115 
    116 void NetlinkRequest::PopList() {
    117   if (lists_.empty()) {
    118     LOG(ERROR) << "List pop with no lists left on stack.";
    119     return;
    120   }
    121 
    122   std::pair<nlattr*, int> list = lists_.back();
    123   lists_.pop_back();
    124   list.first->nla_len = request_.size() - list.second;
    125 }
    126 
    127 void* NetlinkRequest::RequestData() const {
    128   // Update request length before reporting raw data.
    129   header_->nlmsg_len = request_.size();
    130   return header_;
    131 }
    132 
    133 size_t NetlinkRequest::RequestLength() const {
    134   return request_.size();
    135 }
    136 
    137 }  // namespace cvd
    138