GO SNMP implementation

This is a open source SNMP trap receiver written in GO:

https://github.com/tiebingzhang/WapSNMP

It supports SNMP v2c and V3 traps.

It also includes utilities to perform SNMP Get and SNMP walk for both SNMP v2c and V3.

Since it is written in GO, it compiles on both Linux and Windows (and in theory also Mac OS, but not tested).

my .gitconfig

[user]
        name = Tiebing Zhang
        email = tzhang@advistatech.com
[core]
        editor = vim
[merge]
        tool = vimdiff
[alias]
        d = difftool
        st = status -s
        ci = commit -a
        br = branch
        co = checkout
        df = diff
        dc = diff --cached
        last = log -1 HEAD --stat
        lg = log --stat
        who = shortlog -s --
[diff]
        renames = copy
        tool = gvimdiff
[difftool "gvimdiff"]
        cmd = "gvim -d" "$LOCAL" "$REMOTE"
[difftool]
        prompt = false
[push]
        default = matching
[sendpack]
        sideband = false

GO cross compile Windows binary on Linux

# set up cross compilation to windows_amd64
# you only need to do this once
cd $GOROOT/src
GOOS=windows GOARCH=amd64 ./make.bash --no-clean

# whenever you want to cross compile
cd $YOUR_APP
GOOS=windows GOARCH=amd64 go build

More at
https://inconshreveable.com/04-30-2014/cross-compiling-golang-programs-with-native-libraries/

netcat send file with progress indicator

The following C code compiles to a file nc-send-file, and it will send a file to a raw tcp socket (such as netcat with the command: nc -l -p 8000 > myfile ), with progress indicator for every 64K bytes sent. On Windows, compile it using MinGW the following Makefile:

nc-send-file:nc-send-file.c
        gcc -Wall -O2 -o $@ $^ -s -lws2_32
clean:
        rm -f nc-send-file.exe

C code:

#ifdef WIN32
#include "winsock2.h"
#else
#include "sys/socket.h"
#include "netinet/in.h"
#include "unistd.h"
#endif
#include "stdio.h"

int main(int argc, char**argv)
{
   FILE * fd;
   int sockfd,ret,n;
   struct sockaddr_in servaddr;
   char sendline[1024*64];
   unsigned int totalbytes=0;

   if (argc != 4)
   {
      printf("usage:  client [IP address] [PORT] [File]\n");
      exit(1);
   }
#ifdef WIN32
   WSADATA wsaData;
   if (WSAStartup(MAKEWORD(2, 0), &wsaData) != 0){
    fprintf(stderr, "WSAStartup() failed");
    exit(1);
   }
#endif

   sockfd=socket(AF_INET,SOCK_STREAM,0);

   memset(&servaddr,0,sizeof(servaddr));
   servaddr.sin_family = AF_INET;
   servaddr.sin_addr.s_addr=inet_addr(argv[1]);
   servaddr.sin_port=htons(atoi(argv[2]));

   if (connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr))<0){
    fprintf(stderr,"Error connecting to target.\n");
    return -1;
   }

   fd=fopen(argv[3],"rb");
   if (fd==NULL){
    fprintf(stderr,"Opening file %s error\n",argv[3]);
    return -1;
   }

   while (1){
   ret=fread(sendline, 1, sizeof(sendline),fd);
   if (ret==0){
    if (feof(fd)){
     printf("Finished. Total bytes sent:%u\n",totalbytes);
    }else{
     printf("Error.\n");
    }
    break;
   }
      n=send(sockfd,sendline,ret,0);
   if (n!=ret){
    printf("did not send all in the buffer. expecting %d sent %d exit.\n", ret, n);
    return -1;
   }
   totalbytes+=ret;
   printf("sending %d bytes, total %d bytes\n",ret, totalbytes);
   }
   fclose(fd);
#ifdef WIN32
   closesocket(sockfd);
   WSACleanup();  /* Cleanup Winsock */
#else
   close(sockfd);
#endif
   return 0;
}

xrdp reconnect to the same session

cat xrdp/xrdp.ini

[globals]
bitmap_cache=yes
bitmap_compression=yes
port=3389
crypt_level=high
channel_code=1

[xrdp1]
name=sesman-Xvnc
lib=libvnc.so
username=ask
password=ask
ip=127.0.0.1
port=-1

[xrdp2]
name=Reconnect
lib=libvnc.so
username=ask
password=ask
ip=127.0.0.1
#port=-1
port=5910

Use stunnel to access https

stunnel -c -d localhost:8000 -r foo:443 -P /tmp/stunnel.pid -f

Now you can access local 8000 using plaintext so that you can debug and sniff packets.