From Carboogle

Hello,

This is a quick "how to" to setup Libpcap under Cygwin. For Windows, it is just faster downloading the WinPcap Developer's Packs and install the files in Cygwin directories.

Contents 1 For Cygwin 1.1 Setup Winpcap 1.2 Building example using Cygwin 1.2.1 basic_dump 1.2.2 basic_dump_ex 1.2.3 iflist 1.2.4 pcap_filter (and others) 1.2.5 UDPdump 2 For MinGW 2.1 Requirements 2.2 Compiling Winpcap 2.3 Installing Winpcap in MinGW 2.4 Building example using MinGW 2.4.1 basic_dump_ex 2.4.2 iflist 2.4.3 UDPdump

For Cygwin

Setup Winpcap

1. Download and unzip the pack. We will use for this example WpdPack_4_0_1.zip.
2. Copy libraries like this:

• WpdPack\Lib\libpacket.a to cygwin\lib\
• WpdPack\Lib\libwpcap.a to cygwin\lib\

3. Create a folder cygwin\usr\include\pcap\
4. Copy all headers from WpdPack\Include to cygwin\usr\include\winpcap\
5. Be sure you have installed Winpcap libraries and that they are in your path by typing:

• which Packet.dll
• which wpcap.dll

For me they are in /cygdrive/c/WINDOWS/system32/

Building example using Cygwin

basic_dump

Open a cygwin prompt to WpdPack\Examples-pcap\basic_dump\ and execute:

CFLAGS="-g -Wall -mno-cygwin -I /usr/include/pcap"
LIBS="-lwpcap"
PROG="basic_dump"
gcc $CFLAGS -c $PROG.c
gcc $CFLAGS -o $PROG.exe $PROG.o $LIBS
./$PROG.exe

basic_dump_ex

CFLAGS="-g -Wall -mno-cygwin -I /usr/include/pcap"
LIBS="-lwpcap"
PROG="basic_dump_ex"
gcc $CFLAGS -c $PROG.c
gcc $CFLAGS -o $PROG.exe $PROG.o $LIBS
./$PROG.exe

iflist

CFLAGS="-g -Wall -mno-cygwin -I /usr/include/pcap"
LIBS="-lwpcap"
PROG="iflist"
gcc $CFLAGS -c $PROG.c
gcc $CFLAGS -o $PROG.exe $PROG.o $LIBS
./$PROG.exe

pcap_filter (and others)

I think you can catch the pattern ;) Only replace PROG=... by the program name and it should compile.

UDPdump

CFLAGS="-g -Wall -mno-cygwin -I /usr/include/pcap"
LIBS="-lwpcap -lwsock32"
PROG="UDPdump"
gcc $CFLAGS -c $PROG.c
gcc $CFLAGS -o $PROG.exe $PROG.o $LIBS
./$PROG.exe

You can test by doing a Time Synchronization with pool.ntp.org for example.

For MinGW

Requirements

• First install MinGW
• Download Winpcap sources 4.0.1 (if you want to compile)
• Download Airpcap developer pack (if you want to compile)
• Download Winpcap Developer Pack 4.0.1 (if you just want to install)

Basic setup:

1. Unpack Winpcap sources into D:\data\download\winpcap\
2. Unpack Airpcap dev. pack into D:\data\download\Airpcap_Devpack\

Compiling Winpcap

If you are using the same MinGW environment as mine, it is possible that you need to apply the following patch before launching the compilation. I have reported a bug in september 2007 relative to this compilation issue on winpcap bugs mailing list (Patch - Problems compiling Winpcap 4.0.1 with MinGW)

--- /d/data/download/gai_strerror.c     Sun Jan 22 15:14:18 2006
+++ ../libpcap/Win32/Src/gai_strerror.c Tue Sep 18 21:29:11 2007
@@ -67,6 +67,7 @@
 #define EAI_MAX (sizeof(ai_errlist)/sizeof(ai_errlist[0]))
 #endif
 
+#ifndef gai_strerror
 char *
 WSAAPI gai_strerrorA(int ecode)
 {
@@ -74,4 +75,4 @@
                return ai_errlist[ecode];
        return "Unknown error";
 }
-
+#endif 

You can add it manually by editing the file .\winpcap\wpcap\libpcap\Win32\Src\gai_strerror.c and adding the above defines around the function gai_strerrorA

Once the patch applied, you are ready to compile, as written in the readme. Open a console from D:\data\download\winpcap\ and execute the commands:

cd packetNtx/Dll/Project/
make
cd ../../../wpcap/PRJ/
make

Here you should have an error:

Can't open .lib file: ../lib/libwpcap.a
collect2: ld returned 1 exit status
make: *** [main] Error 1

It it just because you need to manually create the lib folder D:\data\download\winpcap\wpcap\lib So after creating this folder, just retype

make

And you should have the following files (for the total):

• D:\data\download\winpcap\packetNtx\Dll\Project\libpacket.a
• D:\data\download\winpcap\wpcap\lib\libwpcap.a
• D:\data\download\winpcap\packetNtx\Dll\Project\Packet.dll
• D:\data\download\winpcap\wpcap\libpcap\rpcapd\win32-pthreads\pthreadVC.dll
• D:\data\download\winpcap\wpcap\PRJ\wpcap.dll

Installing Winpcap in MinGW

The procedure is quite the same as for Cygwin.

1. Copy all the *.a files you built into /local/lib
2. Copy the *.dll files into /local/bin
3. Copy all headers from WpdPack\Include to /local/include/pcap
4. Optional: To facilitate further compilations, i use to copy /local/lib/libwpcap.a to /local/lib/libpcap.a because a lot of Linux programs rely on the original libpcap library which create the second library and not the first one.

Building example using MinGW

basic_dump_ex

In a bash console execute with MinGW:

SRC="basic_dump_ex"
CFLAGS="-I /local/include/pcap"
LDFLAGS="-L /local/lib -lpcap"
gcc $CFLAGS -o $SRC.exe $SRC.c $LDFLAGS

iflist

SRC="iflist"
CFLAGS="-I /local/include/pcap"
LDFLAGS="-L /local/lib -lpcap"
gcc $CFLAGS -o $SRC.exe $SRC.c $LDFLAGS

UDPdump

SRC="udpdump"
CFLAGS="-I /local/include/pcap"
LDFLAGS="-L /local/lib -lpcap -lws2_32"
gcc $CFLAGS -o $SRC.exe $SRC.c $LDFLAGS