#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <sys/wait.h>
#include <sys/resource.h>
#include <arpa/inet.h>
#include <assert.h>
#include <ctype.h>
#include <fcntl.h>
#include <signal.h>

char *server_ip = "127.0.0.1";
char *username = "z";
char *password = "xxxxxxxx";

int s = -1;
int uid = 0;
int tid = 0;
int fid = 0;

unsigned int header_flags = 0;
unsigned int header_flags2 = 0;

int
header(char *buf, int command)
{
  int ii = 0;

  // SMB-over-TCP 4-byte header
  buf[ii++] = 0; // must be zero
  buf[ii++] = 0; // high byte of len
  *(short*)(buf+ii) = htons(sizeof(buf)-4); // non-inclusive len, filled later
  ii += 2;
  
  // 32-byte SMB header, MS-CIFS 2.2.3.1
  buf[ii++] = 0xff;
  buf[ii++] = 'S';
  buf[ii++] = 'M';
  buf[ii++] = 'B';
  buf[ii++] = command;
  buf[ii++] = 0; // status
  buf[ii++] = 0; // status
  buf[ii++] = 0; // status
  buf[ii++] = 0; // status
  buf[ii++] = header_flags; // flags
  *(short*)(buf+ii) = header_flags2; // flags2
  ii += 2;
  *(short*)(buf+ii) = 0; // PIDHigh
  ii += 2;
  ii += 8; // SecurityFeatures
  *(short*)(buf+ii) = 0; // Reserved
  ii += 2;
  *(short*)(buf+ii) = tid; // TID
  ii += 2;
  *(short*)(buf+ii) = 0; // PIDLow
  ii += 2;
  *(short*)(buf+ii) = uid; // UID
  ii += 2;
  *(short*)(buf+ii) = 0; // MID
  ii += 2;

  return ii;
}

void
negotiate(const char *dialect)
{
  // SMB_COM_NEGOTIATE
  // dialect should probably be "NT LM 0.12"
  {
    char buf[128];
    memset(buf, 1, sizeof(buf));

    int ii = header(buf, 0x72);

    // parameter block, MS-CIFS 2.2.3.2
    int param_words = 0;
    buf[ii++] = param_words; // number of 16-bit words of parameters
    printf("parameters start at %d\n", ii);
    ii += param_words*2;

    // data block, MS-CIFS 2.2.3.3
    // SMB_COM_NEGOTIATE MS-CIFS 2.2.4.52
    int bci = ii;
    *(short*)(buf+ii) = 0; // byte count including this len (to be filled in)
    ii += 2;
    buf[ii++] = 0x02; // BufferFormat
    memcpy(buf+ii, dialect, strlen(dialect) + 1);
    ii += strlen(dialect) + 1;

    *(short*)(buf+bci) = ii - bci - 2;

    ii = sizeof(buf); // this works

    *(short*)(buf+2) = htons(ii-4); // non-inclusive len

    assert(ii <= sizeof(buf));

    printf("writing %d bytes\n", ii); fflush(stdout);

    if(write(s, buf, ii) <= 0){
      perror("write");
      exit(1);
    }
  }

  {
    // read negotiate response, MS-CIFS 2.2.4.52.2
    unsigned char buf[1024];
    memset(buf, 0, sizeof(buf));
    int cc = read(s, buf, sizeof(buf));
    printf("read %d for negotiate response\n", cc);
    printf("WordCount %d (expecting 17)\n", buf[36] & 0xff);
    printf("DialectIndex %d (expecting 0)\n", *(short*)(buf+37));
    printf("SecurityMode 0x%x (expecting 0x1)\n", buf[37+2]);
  }
}

void
setup()
{
  // SMB_COM_SESSION_SETUP_ANDX
  // MS-CIFS 3.2.4.2.3
  {
    char buf[128];
    memset(buf, 1, sizeof(buf));

    int ii = header(buf, 0x73);

    // parameter block, MS-CIFS 2.2.4.53.1
    int param_words = 13;
    buf[ii++] = param_words; // number of 16-bit words of parameters
    // ii is 37 at this point
    buf[ii++] = 0xff; // AndXCommand (next command) 0xff means none
    buf[ii++] = 0; // Reserved
    *(short*)(buf+ii) = 0; // AndXOffset
    ii += 2;
    *(short*)(buf+ii) = 8192; // MaxBufferSize
    ii += 2;
    *(short*)(buf+ii) = 2; // MaxMpxCount
    ii += 2;
    *(short*)(buf+ii) = 0; // VcNumber
    ii += 2;
    *(int*)(buf+ii) = 0; // SessionKey, from negotiate response XXX
    ii += 4;
    *(short*)(buf+ii) = strlen(password); // OEMPasswordLen
    ii += 2;
    *(short*)(buf+ii) = 0; // UnicodePasswordLen
    ii += 2;
    *(int*)(buf+ii) = 0; // Reserved
    ii += 4;
    *(int*)(buf+ii) = 0; // Capabilities
    ii += 4;

    // data block
    int bci = ii;
    *(short*)(buf+ii) = 0; // byte count including this len (to be filled in)
    ii += 2;
    // OEMPassword
    memcpy(buf+ii, password, strlen(password));
    ii += 8;
    // pad
    if(ii % 1)
      ii++;
    // AccountName
    memcpy(buf+ii, username, strlen(username) + 1);
    ii += strlen(username) + 1;
    // PrimaryDomain
    buf[ii++] = '\0';
    // NativeOS
    buf[ii++] = '\0';
    // NativeLanMan
    buf[ii++] = '\0';

    *(short*)(buf+bci) = ii - bci - 2;

    ii = sizeof(buf);

    *(short*)(buf+2) = htons(ii-4); // non-inclusive len

    assert(ii <= sizeof(buf));

    printf("writing %d bytes\n", ii); fflush(stdout);

    if(write(s, buf, ii) <= 0){
      perror("write");
      exit(1);
    }
  }

  {
    // read session setup response, MS-CIFS 2.2.4.53.2
    unsigned char buf[1024];
    memset(buf, 0, sizeof(buf));
    int cc = read(s, buf, sizeof(buf));
    printf("read %d for session setup response\n", cc);
    printf("WordCount %d\n", buf[36] & 0xff);
    printf("Action %d (expecting 0)\n", *(short*)(buf+41));
    uid = *(short*)(buf+32);
    uid &= 0xffff;
    printf("UID 0x%x\n", uid);
  }
}

void
tree_connect()
{
  // SMB_COM_TREE_CONNECT_ANDX, MS-CIFS 2.2.4.55
  {
    char buf[128];
    memset(buf, 1, sizeof(buf));

    int ii = header(buf, 0x75);

    // parameter block, MS-CIFS 2.2.4.53.1
    int param_words = 4;
    buf[ii++] = param_words; // number of 16-bit words of parameters
    // ii is 37 at this point
    buf[ii++] = 0xff; // AndXCommand
    buf[ii++] = 0; // Reserved
    *(short*)(buf+ii) = 0; // AndXOffset
    ii += 2;
    *(short*)(buf+ii) = 0; // Flags
    ii += 2;
    *(short*)(buf+ii) = 1; // PasswordLength
    ii += 2;

    // data block
    int bci = ii;
    *(short*)(buf+ii) = 0; // byte count including this len (to be filled in)
    ii += 2;
    buf[ii++] = '\0'; // password
    buf[ii++] = 'x'; // path
    buf[ii++] = '\0';
    buf[ii++] = 'A'; // Service
    buf[ii++] = ':';
    buf[ii++] = '\0';

    *(short*)(buf+bci) = ii - bci - 2;

    ii = sizeof(buf);

    *(short*)(buf+2) = htons(ii-4); // non-inclusive len

    assert(ii <= sizeof(buf));

    printf("writing %d bytes\n", ii); fflush(stdout);

    if(write(s, buf, ii) <= 0){
      perror("write");
      exit(1);
    }
  }

  {
    // read tree connect response, MS-CIFS 2.2.4.55.2
    unsigned char buf[1024];
    memset(buf, 0, sizeof(buf));
    int cc = read(s, buf, sizeof(buf));
    printf("read %d for tree connect response\n", cc);
    tid = *(short*)(buf+28);
    tid &= 0xffff;
    printf("TID 0x%x\n", tid);
  }
}

void
check_directory(char *name)
{
  // SMB_COM_CHECK_DIRECTORY, MS-CIFS 2.2.4.17
  {
    char buf[128];
    memset(buf, 0xff, sizeof(buf));

    int ii = header(buf, 0x10);

    // parameter block
    int param_words = 0x00;
    buf[ii++] = param_words; // number of 16-bit words of parameters
    // ii is 37 at this point

    // data block
    int bci = ii;
    *(short*)(buf+ii) = 0; // byte count including this len (to be filled in)
    ii += 2;
    buf[ii++] = 0x04; // SMB_STRING
    memcpy(buf+ii, name, strlen(name) + 1);
    ii += strlen(name) + 1;

    *(short*)(buf+bci) = ii - bci - 2;

    ii = sizeof(buf);

    *(short*)(buf+2) = htons(ii-4); // non-inclusive len

    assert(ii <= sizeof(buf));

    printf("writing %d bytes\n", ii); fflush(stdout);

    if(write(s, buf, ii) <= 0){
      perror("write");
      exit(1);
    }
  }

  {
    unsigned char buf[1024];
    memset(buf, 0, sizeof(buf));
    int cc = read(s, buf, sizeof(buf));
    printf("read %d for check_directory response\n", cc);
    printf("check_directory Status 0x%x\n", *(unsigned int*)(buf+9));
  }
}

int
main()
{
  signal(SIGPIPE, SIG_IGN);
  signal(SIGTERM, SIG_IGN);

  struct sockaddr_in sin;
  memset(&sin, 0, sizeof(sin));
  sin.sin_family = AF_INET;
  sin.sin_port = htons(445); // SMB over TCP
  sin.sin_addr.s_addr = inet_addr(server_ip);

  while(1){
    s = socket(AF_INET, SOCK_STREAM, 0);
    if(connect(s, (struct sockaddr *)&sin, sizeof(sin)) == 0)
      break;
    close(s);
    sleep(1);
  }

  sleep(1);

  negotiate("NT LM 0.12");
  setup();
  tree_connect();
  header_flags2 |= 0x1000; // DFS
  check_directory("\\x//\\/");

  sleep(1);
  close(s);
}