Chapter 22 examples fix

Author: Artiom N.

src/book01/ch22/cpp/pcap_sniffer/main.cpp

@@ -107,7 +107,7 @@ int main(int argc, const char *const argv[])
         }
 
         // Compile the filter expression.
-        if (pcap_compile(handle, &fp, filter_exp, 0, net) == -1)
+        if (-1 == pcap_compile(handle, &fp, filter_exp, 0, net))
         {
             ss << "Couldn't parse filter \"" << filter_exp << "\": " << pcap_geterr(handle) << "!" << std::endl;
             throw std::logic_error(ss.str());

src/book01/ch22/cpp/pcap_sniffer/packet_printer.cpp

@@ -4,6 +4,7 @@
 #include <iostream>
 #include <string>
 
+
 // Ethernet headers are always exactly 14 bytes.
 constexpr auto SIZE_ETHERNET = 14;
 
@@ -99,6 +100,7 @@ struct sniff_tcp
     tcp_seq th_ack;
     // Data offset, rsvd.
     u_char th_offx2;
+    // cppcheck-suppress unusedStructMember
     tcp_flags th_flags;
     u_short th_win;
     u_short th_sum;
@@ -160,15 +162,15 @@ void PacketPrinter::print_hex_ascii_line(const u_char *payload, int len, int off
 void PacketPrinter::print_payload(const u_char *payload, int len)
 {
     int len_rem = len;
-    // number of bytes per line.
-    int line_width = 16;
-    // zero-based offset counter.
+    // Number of bytes per line.
+    constexpr int line_width = 16;
+    // Zero-based offset counter.
     int offset = 0;
     const u_char *ch = payload;
 
     if (len <= 0) return;
 
-    /* data fits on one line */
+    // Data fits on one line.
     if (len <= line_width)
     {
         print_hex_ascii_line(ch, len, offset);
@@ -190,7 +192,7 @@ void PacketPrinter::print_payload(const u_char *payload, int len)
         // Check if we have line width chars or less.
         if (len_rem <= line_width)
         {
-            /* print last line and get out */
+            // Print last line and get out.
             print_hex_ascii_line(ch, len_rem, offset);
             break;
         }

src/book01/ch22/cpp/pcappp-example/main.cpp

@@ -0,0 +1,38 @@
+#include <pcapplusplus/IPv4Layer.h>
+#include <pcapplusplus/Packet.h>
+#include <pcapplusplus/PcapFileDevice.h>
+
+#include <iostream>
+
+
+int main(int argc, char* argv[])
+{
+    pcpp::PcapFileReaderDevice reader("1_packet.pcap");
+
+    if (!reader.open())
+    {
+        std::cerr << "Error opening the pcap file" << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    pcpp::RawPacket rawPacket;
+    if (!reader.getNextPacket(rawPacket))
+    {
+        std::cerr << "Couldn't read the first packet in the file" << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    pcpp::Packet parsedPacket(&rawPacket);
+
+    if (parsedPacket.isPacketOfType(pcpp::IPv4))
+    {
+        pcpp::IPv4Address srcIP = parsedPacket.getLayerOfType<pcpp::IPv4Layer>()->getSrcIPv4Address();
+        pcpp::IPv4Address destIP = parsedPacket.getLayerOfType<pcpp::IPv4Layer>()->getDstIPv4Address();
+
+        std::cout << "Source IP is '" << srcIP << "'; Dest IP is '" << destIP << "'" << std::endl;
+    }
+
+    reader.close();
+
+    return EXIT_SUCCESS;
+}

src/book01/ch22/cpp/raw_sniffer/sniffer.cpp

@@ -1,6 +1,7 @@
 #include "sniffer.h"
 
 #include <algorithm>
+#include <array>
 #include <cerrno>
 #include <chrono>
 #include <iostream>
@@ -191,21 +192,21 @@ bool Sniffer::capture()
 {
     // First 14 bytes are a fake ethernet header with IPv4 as the protocol.
     // `char` type is using for the compatibility with Windows.
-    char buffer[BUFFER_SIZE_HDR + BUFFER_SIZE_PKT] = {0};
-    // 0x08 - IP protocol type in the Ethernet frame protocolol type field (offset = 12).
-    buffer[BUFFER_OFFSET_ETH + ethernet_proto_type_offset] = 0x08;
-    pcap_sf_pkthdr* pkt = reinterpret_cast<struct pcap_sf_pkthdr*>(buffer);
+    std::array<char, BUFFER_SIZE_HDR + BUFFER_SIZE_PKT> buffer;
+    // 0x08 - IP protocol type in the Ethernet frame protocol type field (offset = 12).
+    buffer[BUFFER_OFFSET_ETH + ethernet_proto_type_offset] = 0x08;  // cppcheck-suppress containerOutOfBounds
+    pcap_sf_pkthdr* pkt = reinterpret_cast<pcap_sf_pkthdr*>(buffer.data());
 
     // Read the next packet, blocking forever.
-    int rc = recv(sock_, buffer + BUFFER_WRITE_OFFSET, BUFFER_SIZE_IP, 0);
+    const int rc = recv(sock_, buffer.data() + BUFFER_WRITE_OFFSET, BUFFER_SIZE_IP, 0);
 
     if (INVALID_SOCKET == rc)
     {
         std::cerr << "recv() failed: " << sock_wrap_.get_last_error_string() << std::endl;
         return false;
     }
 
-    // End of file for some strange reason, so stop reading packets.
+    // Data receiving error, so stop reading packets.
     if (!rc) return false;
 
     std::cout << rc << " bytes received..." << std::endl;
@@ -224,7 +225,7 @@ bool Sniffer::capture()
     pkt->len = rc + BUFFER_ADD_HEADER_SIZE;
 
     // Write packet.
-    of_.write(reinterpret_cast<const char*>(buffer), rc + BUFFER_SIZE_HDR + BUFFER_ADD_HEADER_SIZE);
+    of_.write(buffer.data(), rc + BUFFER_SIZE_HDR + BUFFER_ADD_HEADER_SIZE);
     of_.flush();
 
     return true;

src/book01/ch22/python/promisc_switcher/promisc_switcher.py

@@ -15,21 +15,17 @@ class InterfacePromiscSwitcher(ctypes.Structure):
 
     def __init__(self, if_name: str, *args, **kw):
         super().__init__(*args, **kw)
-        self._sock: socket.socket
-        if 'socket' in kw:
-            self._sock = kw['socket']
-        else:
-            self._sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        self._sock = kw['socket'] if 'socket' in kw else socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
 
         self.ifr_ifrn = if_name.encode()
 
     @property
     def socket(self) -> socket.socket | None:
-        return self._sock
+        return self._sock  # type: ignore
 
     def set_promisc(self):
         sock = self._sock
-        if sys.platform == 'win32':
+        if 'win32' == sys.platform:
             sock.bind((self.ifr_ifrn, 0))
             sock.ioctl(socket.SIO_RCVALL, socket.RCVALL_ON)
         else:
@@ -38,8 +34,8 @@ def set_promisc(self):
             ioctl(sock.fileno(), self.SIOCSIFFLAGS, self)
 
     def unset_promisc(self, close_socket: bool = True):
-        if sys.platform == 'win32':
-            self._sock.ioctl(socket.SIO_RCVALL, socket.RCVALL_OFF)
+        if 'win32' == sys.platform:
+            self._sock.ioctl(socket.SIO_RCVALL, socket.RCVALL_OFF)  # type: ignore[attr-defined]
         else:
             self.ifr_flags &= ~self.IFF_PROMISC  # pylint: disable=E1101(no-member)
             ioctl(self._sock.fileno(), self.SIOCSIFFLAGS, self)

src/book01/ch22/python/python-sniffer.py

@@ -57,7 +57,7 @@ def payload_offset(self) -> int:
 
     @final
     @classmethod
-    def unpack_packet(cls, base_protocol, packet, skip_channel_proto_check: bool = False) -> list[Any]:
+    def unpack_packet(cls, base_protocol, packet, *, skip_channel_proto_check: bool = False) -> list[Any]:
         """Package unpacking method."""
         if not issubclass(base_protocol, NetworkProtocolHeader):
             raise TypeError(