feat(scanner): add subnet ping scan and TCP port scans for alive hosts

Introduce subnet scanning using CIDR prefix notation and perform TCP port scans
on each discovered alive host. The change replaces the full port scan with a
two-step process: first pinging the subnet to find active devices, then scanning
their open TCP ports.

src/cli/portscan_cli.cpp

@@ -4,7 +4,6 @@
 
 PortScanCli::PortScanCli()
     : CliBase("Port Scanner Options")
-    , ip_("")
 {
 }
 
@@ -13,14 +12,17 @@ void PortScanCli::setupOptions()
     // clang-format off
     desc_.add_options()
         ("help,h",      "Show help")
-        ("ip,H",       withDefault(ip_, "<IP>"),    "Local IPv4 to scan");
+        ("ip,H",        withDefault(ip_, "<IPv4>"),      "Base IPv4 inside your LAN (e.g. 10.0.1.42)")
+        ("prefix,p",    withDefault(prefix_, "<0..32>"), "CIDR prefix length (e.g. 24)");
     // clang-format on
 }
 
-std::string PortScanCli::getIp() const
+int PortScanCli::getPrefix() const
 {
-    if (vm_["ip"].empty() == 0) {
+    return vm_.at("prefix").as<int>();
-        return "127.0.0.1";
 }
+
+std::string PortScanCli::getBaseIp() const
+{
     return vm_.at("ip").as<std::string>();
 }

src/cli/portscan_cli.hpp

@@ -9,11 +9,13 @@ class PortScanCli : public CliBase, protected OptionUtils
   public:
     PortScanCli();
 
-    std::string getIp() const;
+    int getPrefix() const;
+    std::string getBaseIp() const;
 
   protected:
     void setupOptions() override;
 
   private:
-    std::string ip_;
+    int prefix_{24};
+    std::string ip_{"10.0.1.0"};
 };

src/core/local_ping_scanner.cpp

@@ -0,0 +1,103 @@
+#include "local_ping_scanner.hpp"
+#include "logger.hpp"
+#include <Poco/Net/ICMPClient.h>
+#include <boost/asio/ip/address_v4.hpp>
+#include <stdexcept>
+
+LocalPingScanner::LocalPingScanner(
+    const std::string &baseIp, int prefixLen, int timeoutMs
+)
+    : baseIp_(baseIp)
+    , prefixLen_(prefixLen)
+    , timeoutMs_(timeoutMs)
+{
+    if (prefixLen_ < 0 || prefixLen_ > 32) {
+        Logger::error("Invalid prefix length in LocalPingScanner constructor");
+        throw std::runtime_error("Bad prefix length");
+    }
+    if (timeoutMs_ <= 0) {
+        timeoutMs_ = 2000;
+    }
+}
+
+const std::vector<std::string> &LocalPingScanner::alive() const
+{
+    return alive_;
+}
+
+uint32_t LocalPingScanner::ipToU32(const std::string &ip)
+{
+    using namespace boost::asio::ip;
+    return static_cast<uint32_t>(make_address_v4(ip).to_uint());
+}
+
+std::string LocalPingScanner::u32ToIp(uint32_t v)
+{
+    using namespace boost::asio::ip;
+    return address_v4(v).to_string();
+}
+
+bool LocalPingScanner::pingHost(const std::string &ip) const
+{
+    try {
+        return Poco::Net::ICMPClient::pingIPv4(
+                   ip,
+                   /*repeat=*/1,
+                   /*dataSize=*/48,
+                   /*ttl=*/64,
+                   /*timeout=*/timeoutMs_
+               )
+               > 0;
+    } catch (const std::exception &ex) {
+        Logger::error(
+            std::string("Ping failed for host ") + ip + ": " + ex.what()
+        );
+        return false;
+    } catch (...) {
+        Logger::fatal(std::string("Unknown error pinging host ") + ip);
+        return false;
+    }
+}
+
+void LocalPingScanner::runImpl()
+{
+    alive_.clear();
+
+    const uint32_t base = ipToU32(baseIp_);
+    const uint32_t mask =
+        (prefixLen_ == 0) ? 0u : (0xFFFFFFFFu << (32 - prefixLen_));
+    const uint32_t network = base & mask;
+    const uint32_t broadcast = network | (~mask);
+
+    // No hosts when prefix is too tight (e.g., /32).
+    if (broadcast - network <= 2) {
+        return;
+    }
+
+    const std::string selfIp = u32ToIp(base);
+
+    for (uint32_t v = network + 1; v < broadcast; ++v) {
+        const std::string ipStr = u32ToIp(v);
+
+        if (ipStr == selfIp) {
+            continue;
+        }
+
+        if (pingHost(ipStr)) {
+            alive_.push_back(ipStr);
+        }
+    }
+}
+
+void LocalPingScanner::run()
+{
+    try {
+        runImpl();
+    } catch (const std::exception &ex) {
+        Logger::error(
+            std::string("Exception in LocalPingScanner::run: ") + ex.what()
+        );
+    } catch (...) {
+        Logger::fatal("Unknown exception in LocalPingScanner::run");
+    }
+}

src/core/local_ping_scanner.hpp

@@ -0,0 +1,26 @@
+#pragma once
+#include <cstdint>
+#include <string>
+#include <vector>
+
+class LocalPingScanner
+{
+  public:
+    LocalPingScanner(
+        const std::string &baseIp, int prefixLen, int timeoutMs = 2000
+    );
+
+    void run(); // blocking scan over subnet
+    const std::vector<std::string> &alive() const;
+
+  private:
+    static std::string u32ToIp(uint32_t v);
+    static uint32_t ipToU32(const std::string &ip);
+    bool pingHost(const std::string &ip) const;
+    void runImpl();
+
+    std::string baseIp_;
+    int prefixLen_;
+    int timeoutMs_;
+    std::vector<std::string> alive_;
+};

src/core/port_scanner.cpp

@@ -1,142 +1,126 @@
 #include "port_scanner.hpp"
 #include "logger.hpp"
-#include <boost/asio.hpp>
+#include <algorithm>
-#include <string>
 
-PortScanner::PortScanner(
+PortScanner::PortScanner(std::string ip, int timeoutMs)
-    const std::string &ip, const std::vector<uint16_t> &ports
+    : ip_(std::move(ip))
-)
+    , timeoutMs_(timeoutMs)
-    : ports_(ports)
 {
-    ErrorCode ec;
+    if (timeoutMs_ <= 0) {
-    addr_ = boost::asio::ip::make_address(ip, ec);
+        timeoutMs_ = 250;
-    ip_ok_ = !ec;
-
-    if (!ip_ok_) {
-        Logger::error(std::string("PortScanner: invalid IP: ") + ip);
-    } else {
-        Logger::debug(std::string("PortScanner: using IP: ") + ip);
     }
 }
 
-void PortScanner::setTimeoutMs(int ms)
+PortScanner::Probe::Probe(IoContext &io, uint16_t p)
+    : port(p)
+    , socket(io)
+    , timer(io)
 {
-    if (ms > 0) {
-        timeout_ms_ = ms;
-        Logger::debug(
-            std::string("PortScanner: timeout set to ")
-            + std::to_string(timeout_ms_) + " ms"
-        );
 }
+
+const std::vector<uint16_t> &PortScanner::openPorts() const
+{
+    return openPorts_;
 }
 
 void PortScanner::run()
 {
-    if (!ip_ok_) {
+    openPorts_.clear();
-        Logger::error("PortScanner::run - aborting: ip not ok");
+    nextPort_ = kFirstPort;
+    outstanding_ = 0;
+    active_.clear();
+
+    while (outstanding_ < kMaxConcurrency && nextPort_ <= kLastPort) {
+        startNext();
+    }
+
+    io_.run();
+}
+
+void PortScanner::startNext()
+{
+    if (nextPort_ > kLastPort) {
         return;
     }
-    for (uint16_t p : ports_) {
+
-        if (probe(p)) {
+    const uint16_t port = static_cast<uint16_t>(nextPort_);
-            Logger::info(std::to_string(p));
+    nextPort_ += 1;
-        }
+
-    }
+    startProbe(port);
 }
 
-bool PortScanner::probe(uint16_t port)
+void PortScanner::startProbe(uint16_t port)
 {
-    TcpSocket s(io_);
+    // Lifetime of Probe is managed in 'active_' until probe finishes.
-    SteadyTimer t(io_);
+    auto prPtr = std::make_unique<Probe>(io_, port);
-    auto ep = endpoint(port);
+    Probe *pr = prPtr.get();
+    active_.push_back(std::move(prPtr));
 
-    Logger::debug(
+    outstanding_ += 1;
-        std::string("PortScanner::probe - probing port ") + std::to_string(port)
-    );
 
-    armTimer(t, s);
-    armConnect(s, ep);
-    runUntilDone();
-    cancelTimer(t);
-    drainLeftovers();
-    close(s);
-
-    if (ok_) {
-        Logger::debug(std::string("Port ") + std::to_string(port) + " is OPEN");
-    } else {
-        Logger::debug(
-            std::string("Port ") + std::to_string(port) + " is CLOSED/FILTERED"
-        );
-    }
-
-    return ok_;
-}
-
-TcpEndpoint PortScanner::endpoint(uint16_t port) const
     {
-    return TcpEndpoint(addr_, port);
+        using namespace boost::asio::ip;
-}
 
-void PortScanner::armTimer(SteadyTimer &t, TcpSocket &s)
+        TcpEndpoint ep(make_address_v4(ip_), port);
-{
-    t.expires_after(std::chrono::milliseconds(timeout_ms_));
 
-    auto onTimeout = [&s](const ErrorCode &ec) {
+        pr->timer.expires_after(std::chrono::milliseconds(timeoutMs_));
+
+        auto onTimer = [pr](const ErrorCode &ec) {
+            // Cancel socket on timeout; completion will run onConnect with
+            // ec=operation_aborted.
             if (!ec) {
-            Logger::debug("Timer expired -> cancelling socket");
+                pr->socket.cancel();
-            s.cancel();
             }
         };
 
-    t.async_wait(onTimeout);
+        auto onAsyncConnect = [this, pr](const ErrorCode &ec) {
-}
+            onConnect(pr, ec);
-
-void PortScanner::armConnect(TcpSocket &s, const TcpEndpoint &ep)
-{
-    ok_ = false;
-    done_ = false;
-
-    auto onConnect = [this](const ErrorCode &ec) {
-        if (!ec) {
-            ok_ = true;
-            Logger::debug("async_connect succeeded");
-        } else {
-            ok_ = false;
-            Logger::debug(std::string("async_connect failed: ") + ec.message());
-        }
-        done_ = true;
         };
 
-    s.async_connect(ep, onConnect);
+        pr->timer.async_wait(onTimer);
-}
+        pr->socket.async_connect(ep, onAsyncConnect);
-
-void PortScanner::runUntilDone()
-{
-    io_.restart();
-    while (!done_ && io_.run_one()) {
     }
 }
 
-void PortScanner::cancelTimer(SteadyTimer &t)
+void PortScanner::onConnect(Probe *pr, const ErrorCode &ec)
 {
-    ErrorCode ec;
+    pr->timer.cancel();
-    t.cancel();
+
-    if (ec) {
+    // Open if connect succeeded; REFUSED means closed but host is alive.
-        Logger::warn(std::string("cancelTimer: ") + ec.message());
+    if (!ec) {
-    }
+        openPorts_.push_back(pr->port);
+        Logger::info(std::string("Open port: ") + std::to_string(pr->port));
     }
 
-void PortScanner::drainLeftovers()
+    ErrorCode ignored;
-{
+    pr->socket.close(ignored);
-    io_.restart();
+
-    while (io_.run_one()) {
+    finishProbe(pr);
-        continue;
-    }
 }
 
-void PortScanner::close(TcpSocket &s)
+void PortScanner::finishProbe(Probe *pr)
 {
-    ErrorCode ig;
+    if (outstanding_ > 0) {
-    if (s.close(ig)) {
+        outstanding_ -= 1;
-        Logger::warn(std::string("close socket failed: ") + ig.message());
+    }
+
+    // Remove 'pr' from active_ (active_ size <= kMaxConcurrency, linear
+    // erase is fine).
+    auto it = std::find_if(
+        active_.begin(), active_.end(), [pr](const std::unique_ptr<Probe> &u) {
+            return u.get() == pr;
+        }
+    );
+    if (it != active_.end()) {
+        active_.erase(it);
+    }
+
+    if (nextPort_ <= kLastPort) {
+        startNext();
+    }
+
+    if (outstanding_ == 0 && nextPort_ > kLastPort) {
+        io_.stop();
+        return;
     }
 }

src/core/port_scanner.hpp

@@ -1,37 +1,43 @@
 #pragma once
 #include "aliases.hpp"
-#include <boost/asio.hpp>
 #include <cstdint>
+#include <memory>
 #include <string>
 #include <vector>
 
 class PortScanner
 {
   public:
-    PortScanner(const std::string &ip, const std::vector<uint16_t> &ports);
+    explicit PortScanner(std::string ip, int timeoutMs = 250);
 
-    void setTimeoutMs(int ms);
+    void run(); // blocking scan
-
+    const std::vector<uint16_t> &openPorts() const;
-    void run();
 
   private:
-    bool probe(uint16_t port);
+    struct Probe {
-    TcpEndpoint endpoint(uint16_t port) const;
+        uint16_t port{0};
+        TcpSocket socket;
+        SteadyTimer timer;
 
-    void armTimer(SteadyTimer &t, TcpSocket &s);
+        Probe(IoContext &io, uint16_t p);
-    void armConnect(TcpSocket &s, const TcpEndpoint &ep);
+    };
-    void runUntilDone();
+
-    void cancelTimer(SteadyTimer &t);
+    void startNext();
-    void drainLeftovers();
+    void startProbe(uint16_t port);
-    void close(TcpSocket &s);
+    void onConnect(Probe *pr, const ErrorCode &ec);
-
+    void finishProbe(Probe *pr);
-  private:
+
-    IoContext io_;
+    // Fixed settings
-    IpAddress addr_;
+    static constexpr uint16_t kFirstPort = 1;
-    std::vector<uint16_t> ports_;
+    static constexpr uint16_t kLastPort = 65535;
-
+    static constexpr std::size_t kMaxConcurrency = 256;
-    int timeout_ms_{300};
+
-    bool ip_ok_{false};
+    // State
-    bool ok_{false};
+    std::string ip_;
-    bool done_{false};
+    IoContext io_;
+    std::vector<uint16_t> openPorts_;
+    std::vector<std::unique_ptr<Probe>> active_; // <= kMaxConcurrency
+    uint32_t nextPort_{kFirstPort};
+    std::size_t outstanding_{0};
+    int timeoutMs_;
 };

src/main.cpp

@@ -1,20 +1,8 @@
-#include "cli_base.hpp"
+#include "local_ping_scanner.hpp"
 #include "logger.hpp"
 #include "port_scanner.hpp"
 #include "portscan_cli.hpp"
-
 #include <string>
-#include <vector>
-
-static std::vector<uint16_t> allPorts()
-{
-    std::vector<uint16_t> v;
-    v.reserve(65535);
-    for (uint32_t p = 1; p <= 65535; ++p) {
-        v.push_back(static_cast<uint16_t>(p));
-    }
-    return v;
-}
 
 int main(int argc, char **argv)
 {
@@ -27,12 +15,47 @@ int main(int argc, char **argv)
         return 0;
     }
 
-    const std::string ip = cli.getIp();
+    const std::string baseIp = cli.getBaseIp();
-    auto ports = allPorts();
+
+    const int prefix = cli.getPrefix();
+    if (prefix < 0 || prefix > 32) {
+        Logger::fatal("Prefix must be in range 0..32\n");
+        return 2;
+    }
+
+    LocalPingScanner scanner(baseIp, prefix);
+    Logger::info(std::format("Scanning subnet: {}/{}", baseIp, prefix));
 
-    Logger::info("Starting full port scan (1..65535)...");
-    PortScanner scanner(ip, ports);
     scanner.run();
-    Logger::info("Scan completed.");
+
+    const auto &alive = scanner.alive();
+    if (alive.empty()) {
+        Logger::info("No alive hosts found.\n");
+        return 0;
+    }
+
+    std::cout << "Alive hosts:\n";
+    for (const auto &ip : alive) {
+        std::cout << "  " << ip << "\n";
+    }
+
+    // For each alive host, run full TCP port scan
+    for (const auto &ip : alive) {
+        std::cout << "Scanning ports on " << ip << " ...\n";
+
+        PortScanner ps(ip);
+        ps.run();
+
+        const auto &open = ps.openPorts();
+        if (open.empty()) {
+            std::cout << "  No open TCP ports found on " << ip << "\n";
+        } else {
+            std::cout << "  Open ports on " << ip << ":\n";
+            for (uint16_t port : open) {
+                std::cout << "    " << port << "\n";
+            }
+        }
+    }
+
     return 0;
 }

xmake.lua

@@ -10,10 +10,18 @@ add_requires("cmake::Boost", {
     },
 })
 
+add_requires("cmake::Poco", {
+    alias = "poco",
+    system = true,
+    configs = {
+        components = { "Net", "Foundation" },
+    },
+})
+
 target "port_scanner"
 do
     set_kind "binary"
     add_files("src/main.cpp", "src/cli/*.cpp", "src/common/*.cpp", "src/core/*.cpp")
     add_includedirs("src", "src/cli", "src/common", "src/core", { public = true })
-    add_packages "boost"
+    add_packages("boost", "poco")
 end