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/*
* Copyright (C) 2017 The Android Open Source Project
*
* 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.
*/
#define LOG_TAG "WakeupController"
#include <arpa/inet.h>
#include <iostream>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_log.h>
#include <sys/socket.h>
#include <netinet/if_ether.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <android-base/strings.h>
#include <android-base/stringprintf.h>
#include <log/log.h>
#include <netdutils/Netfilter.h>
#include <netdutils/Netlink.h>
#include "IptablesRestoreController.h"
#include "NetlinkManager.h"
#include "WakeupController.h"
namespace android {
namespace net {
using base::StringPrintf;
using netdutils::Slice;
using netdutils::Status;
const char WakeupController::LOCAL_MANGLE_INPUT[] = "wakeupctrl_mangle_INPUT";
const uint32_t WakeupController::kDefaultPacketCopyRange =
sizeof(struct tcphdr) + sizeof(struct ip6_hdr);
static void extractIpPorts(WakeupController::ReportArgs& args, Slice payload) {
switch (args.ipNextHeader) {
case IPPROTO_TCP: {
struct tcphdr header;
if (extract(payload, header) < sizeof(struct tcphdr)) {
return;
}
args.srcPort = ntohs(header.th_sport);
args.dstPort = ntohs(header.th_dport);
break;
}
case IPPROTO_UDP: {
struct udphdr header;
if (extract(payload, header) < sizeof(struct udphdr)) {
return;
}
args.srcPort = ntohs(header.uh_sport);
args.dstPort = ntohs(header.uh_dport);
break;
}
default:
break;
}
}
static void extractIpHeader(WakeupController::ReportArgs& args, Slice payload) {
switch (args.ethertype) {
case ETH_P_IP: {
struct iphdr header;
if (extract(payload, header) < sizeof(struct iphdr)) {
return;
}
args.ipNextHeader = header.protocol;
char addr[INET_ADDRSTRLEN] = {};
inet_ntop(AF_INET, &header.saddr, addr, sizeof(addr));
args.srcIp = addr;
inet_ntop(AF_INET, &header.daddr, addr, sizeof(addr));
args.dstIp = addr;
extractIpPorts(args, drop(payload, header.ihl * 4)); // ipv4 IHL counts 32 bit words.
break;
}
case ETH_P_IPV6: {
struct ip6_hdr header;
if (extract(payload, header) < sizeof(struct ip6_hdr)) {
return;
}
args.ipNextHeader = header.ip6_nxt;
char addr[INET6_ADDRSTRLEN] = {};
inet_ntop(AF_INET6, &header.ip6_src, addr, sizeof(addr));
args.srcIp = addr;
inet_ntop(AF_INET6, &header.ip6_dst, addr, sizeof(addr));
args.dstIp = addr;
// TODO: also deal with extension headers
if (args.ipNextHeader == IPPROTO_TCP || args.ipNextHeader == IPPROTO_UDP) {
extractIpPorts(args, drop(payload, sizeof(header)));
}
break;
}
default:
break;
}
}
WakeupController::~WakeupController() {
expectOk(mListener->unsubscribe(NetlinkManager::NFLOG_WAKEUP_GROUP));
}
netdutils::Status WakeupController::init(NFLogListenerInterface* listener) {
mListener = listener;
const auto msgHandler = [this](const nlmsghdr&, const nfgenmsg&, const Slice msg) {
struct WakeupController::ReportArgs args = {
.uid = -1,
.gid = -1,
.ethertype = -1,
.ipNextHeader = -1,
.srcPort = -1,
.dstPort = -1,
// and all other fields set to 0 as the default
};
bool parseAgain = false;
const auto attrHandler = [&args, &parseAgain](const nlattr attr, const Slice payload) {
switch (attr.nla_type) {
case NFULA_TIMESTAMP: {
timespec ts = {};
extract(payload, ts);
constexpr uint64_t kNsPerS = 1000000000ULL;
args.timestampNs = ntohl(ts.tv_nsec) + (ntohl(ts.tv_sec) * kNsPerS);
break;
}
case NFULA_PREFIX:
// Strip trailing '\0'
args.prefix = toString(take(payload, payload.size() - 1));
break;
case NFULA_UID:
extract(payload, args.uid);
args.uid = ntohl(args.uid);
break;
case NFULA_GID:
extract(payload, args.gid);
args.gid = ntohl(args.gid);
break;
case NFULA_HWADDR: {
struct nfulnl_msg_packet_hw hwaddr = {};
extract(payload, hwaddr);
size_t hwAddrLen = ntohs(hwaddr.hw_addrlen);
hwAddrLen = std::min(hwAddrLen, sizeof(hwaddr.hw_addr));
args.dstHw.assign(hwaddr.hw_addr, hwaddr.hw_addr + hwAddrLen);
break;
}
case NFULA_PACKET_HDR: {
struct nfulnl_msg_packet_hdr packetHdr = {};
extract(payload, packetHdr);
args.ethertype = ntohs(packetHdr.hw_protocol);
break;
}
case NFULA_PAYLOAD:
// The packet payload is expected to come last in the Netlink message.
// At that point NFULA_PACKET_HDR has already been parsed and processed.
// If this is not the case, set parseAgain to true.
parseAgain = (args.ethertype == -1);
extractIpHeader(args, payload);
break;
default:
break;
}
};
forEachNetlinkAttribute(msg, attrHandler);
if (parseAgain) {
// NFULA_PAYLOAD was parsed before NFULA_PACKET_HDR.
// Now that the ethertype is known, reparse msg for correctly extracting the payload.
forEachNetlinkAttribute(msg, attrHandler);
}
mReport(args);
};
return mListener->subscribe(NetlinkManager::NFLOG_WAKEUP_GROUP,
WakeupController::kDefaultPacketCopyRange, msgHandler);
}
Status WakeupController::addInterface(const std::string& ifName, const std::string& prefix,
uint32_t mark, uint32_t mask) {
return execIptables("-A", ifName, prefix, mark, mask);
}
Status WakeupController::delInterface(const std::string& ifName, const std::string& prefix,
uint32_t mark, uint32_t mask) {
return execIptables("-D", ifName, prefix, mark, mask);
}
Status WakeupController::execIptables(const std::string& action, const std::string& ifName,
const std::string& prefix, uint32_t mark, uint32_t mask) {
// NFLOG messages to batch before releasing to userspace
constexpr int kBatch = 8;
// Max log message rate in packets/second
constexpr int kRateLimit = 10;
const char kFormat[] =
"*mangle\n%s %s -i %s -j NFLOG --nflog-prefix %s --nflog-group %d --nflog-threshold %d"
" -m mark --mark 0x%08x/0x%08x -m limit --limit %d/s\nCOMMIT\n";
const auto cmd = StringPrintf(
kFormat, action.c_str(), WakeupController::LOCAL_MANGLE_INPUT, ifName.c_str(),
prefix.c_str(), NetlinkManager::NFLOG_WAKEUP_GROUP, kBatch, mark, mask, kRateLimit);
std::string out;
auto rv = mIptables->execute(V4V6, cmd, &out);
if (rv != 0) {
auto s = Status(rv, "Failed to execute iptables cmd: " + cmd + ", out: " + out);
ALOGE("%s", toString(s).c_str());
return s;
}
return netdutils::status::ok;
}
} // namespace net
} // namespace android
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