PACKET TRACER-"https://gofile.io/d/8nOa4Q"
TCP SOCKET PROGRAMMING

TCP SERVER

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
int main(){
  char *ip = "127.0.0.1";
  int port = 5566;
  int server_sock, client_sock;
  struct sockaddr_in server_addr, client_addr;
  socklen_t addr_size;
  char buffer[1024];
  int n;
  server_sock = socket(AF_INET, SOCK_STREAM, 0);
  if (server_sock < 0){
    perror("[-]Socket error");
    exit(1); }
  printf("[+]TCP server socket created.\n");
 memset(&server_addr, '\0', sizeof(server_addr));
  server_addr.sin_family = AF_INET;
  server_addr.sin_port = port;
  server_addr.sin_addr.s_addr = inet_addr(ip);
  n = bind(server_sock, (struct sockaddr*)&server_addr, sizeof(server_addr));
if (n < 0){
    perror("[-]Bind error");
    exit(1);}
  printf("[+]Bind to the port number: %d\n", port);
  listen(server_sock, 5);printf("Listening...\n");


 while(1){
    addr_size = sizeof(client_addr);
    client_sock = accept(server_sock, (struct sockaddr*)&client_addr, &addr_size);
    printf("[+]Client connected.\n");
    bzero(buffer, 1024);
    recv(client_sock, buffer, sizeof(buffer), 0);
    printf("Client: %s\n", buffer);
    bzero(buffer, 1024);
    strcpy(buffer, "HI, THIS IS SERVER. HAVE A NICE DAY!!!");
    printf("Server: %s\n", buffer);
    send(client_sock, buffer, strlen(buffer), 0);
    close(client_sock);
    printf("[+]Client disconnected.\n\n"); }
  return 0;
}

TCP CLIENT

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
int main(){
  char *ip = "127.0.0.1";
  int port = 5566;
   int sock;
  struct sockaddr_in addr;
  socklen_t addr_size;
  char buffer[1024];
  int n;
  sock = socket(AF_INET, SOCK_STREAM, 0);
  if (sock < 0){
    perror("[-]Socket error");
    exit(1);
  }
  printf("[+]TCP server socket created.\n");
  memset(&addr, '\0', sizeof(addr));
  addr.sin_family = AF_INET;
  addr.sin_port = port;
  addr.sin_addr.s_addr = inet_addr(ip);
  connect(sock, (struct sockaddr*)&addr, sizeof(addr));
  printf("Connected to the server.\n");
  bzero(buffer, 1024);
  scanf("%s",buffer);
  printf("enter message:\n");
  printf("Client: %s\n", buffer);
  send(sock, buffer, strlen(buffer), 0);

  bzero(buffer, 1024);
  recv(sock, buffer, sizeof(buffer), 0);
  printf("Server: %s\n", buffer);

  close(sock);
  printf("Disconnected from the server.\n");

  return 0;
}

EXECUTION :
OPEN 2 TERMINALS IN SAME FOLDER
first terminal
RUN SERVER FIRST - gcc server.c -o server
./server
2nd terminal
RUN client - gcc client.c -o client
./client


UDP SERVER

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int main(int argc, char **argv){

  if (argc != 2){
    printf("Usage: %s <port>\n", argv[0]);
    exit(0);
  }

  char *ip = "127.0.0.1";
  int port = atoi(argv[1]);

  int sockfd;
  struct sockaddr_in server_addr, client_addr;
  char buffer[1024];
  socklen_t addr_size;
  int n;

  sockfd = socket(AF_INET, SOCK_DGRAM, 0);
  if (sockfd < 0){
    perror("[-]socket error");
    exit(1);
  }

  memset(&server_addr, '\0', sizeof(server_addr));
  server_addr.sin_family = AF_INET;
  server_addr.sin_port = htons(port);
  server_addr.sin_addr.s_addr = inet_addr(ip);

  n = bind(sockfd, (struct sockaddr*)&server_addr, sizeof(server_addr));
  if (n < 0) {
    perror("[-]bind error");
    exit(1);
  }

  bzero(buffer, 1024);
  addr_size = sizeof(client_addr);
  recvfrom(sockfd, buffer, 1024, 0, (struct sockaddr*)&client_addr, &addr_size);
  printf("[+]Data recv: %s\n", buffer);

  bzero(buffer, 1024);
  strcpy(buffer, "Welcome to the UDP Server.");
  sendto(sockfd, buffer, 1024, 0, (struct sockaddr*)&client_addr, sizeof(client_addr));
  printf("[+]Data send: %s\n", buffer);

  return 0;
}


UDP CLIENT

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int main(int argc, char **argv){

  if (argc != 2) {
    printf("Usage: %s <port>\n", argv[0]);
    exit(0);
  }

  char *ip = "127.0.0.1";
  int port = atoi(argv[1]);

  int sockfd;
  struct sockaddr_in addr;
  char buffer[1024];
  socklen_t addr_size;

  sockfd = socket(AF_INET, SOCK_DGRAM, 0);
  memset(&addr, '\0', sizeof(addr));
  addr.sin_family = AF_INET;
  addr.sin_port = htons(port);
  addr.sin_addr.s_addr = inet_addr(ip);

  bzero(buffer, 1024);
  strcpy(buffer, "Hello, World!");
  sendto(sockfd, buffer, 1024, 0, (struct sockaddr*)&addr, sizeof(addr));
  printf("[+]Data send: %s\n", buffer);

  bzero(buffer, 1024);
  addr_size = sizeof(addr);
  recvfrom(sockfd, buffer, 1024, 0, (struct sockaddr*)&addr, &addr_size);
  printf("[+]Data recv: %s\n", buffer);

  return 0;
}

EXECUTION :
OPEN 2 TERMINALS IN SAME FOLDER
first terminal
RUN SERVER FIRST - gcc server.c -o server
./server 4444
2nd terminal
RUN client - gcc client.c -o client
./client 4444


parity checking


#include <stdio.h>
#include<string.h>
int main() {
   char a[10] = {0};
   gets(a);
   int ones = 0 ;
   for(int i = 0 ; i < sizeof(a); i++)
   {
       if(a[i] == '1')
       {
           ones = ones + 1 ;
       }
   }
   printf("%d\n",ones);
   if ( ones%2 == 0)
   {
       printf("even parity");
   }
   else
   {
       printf("odd parity");
   }
    return 0;
}

leaky bucket algorithm

#include <stdio.h>
#define max_size 10
int main() {
    int n,pac_size[max_size],capacity,rate,sent,remn=0;
    printf("enter number of the packets:");
    scanf("%d",&n);
    printf("\nenter bucket input size/capacity: ");
    scanf("%d",&capacity);
    printf("\nenter bucket output size/rate: ");
    scanf("%d",&rate);
    printf("\nenter each packet size:");
    for( int i = 0 ; i < n ; i++)
    {

        scanf("%d\n",&pac_size[i]);
    }
    for(int i = 0 ; i < n ; i++)
    {
        printf("packet %d\n",i);
        if(pac_size[i] < capacity)
        {
            printf("packet is accepted into the bucket\n");
            if(pac_size[i] + remn <= rate)
            {
                sent = pac_size[i] + remn;
                remn = 0 ;
                printf("sent = %d\n",sent);
                printf("remaning = %d",remn);
            }
            else
            {
                sent = rate;
                remn = (pac_size[i]+remn)-sent;
                printf("sent = %d\n",sent);
                printf("remaning = %d\n",remn);
            }
        }
        else
        {
           printf("packet of size  %d is not accepted as %d is greater than capacity\n",pac_size[i],capacity);
        }
    }
    return 0 ;
}
//CHECKSUM IN C
#include<stdio.h>
int add(int,int);
int com(int);
void main()
{
 int i,j,dl,dil;
 int data1[10],data2[10],newdata[10],comp[10],checksum[10];
 printf("\n Enter the data length=");
 scanf("%d",&dl);
 printf("\n Enter the data1 : \n");
 for(i=0;i<dl;i++)
  scanf("%d",&data1[i]);
  printf("\n Enter the data2 : \n");
 for(i=0;i<dl;i++)
  scanf("%d",&data2[i]);
            for(i=dl-1;i>=0;i--)
            {
            newdata[i]=add(data1[i],data2[i]);
            }

 printf("\n\n Data 1        : ");
 for(i=0;i<dl;i++)
            printf("%d",data1[i]);
 printf("\n Data 2        : ");
 for(i=0;i<dl;i++)
            printf("%d",data2[i]);

 printf("\n\n The new data is : ");
 for(i=0;i<dl;i++)
 {
   printf("%d",newdata[i]);
 }
  printf("\n Checksum : ");
 for(i=0;i<dl;i++)
 {
   checksum[i]=com(newdata[i]);
   printf("%d",checksum[i]);
 }

 printf("\n\n Receiver Side : \n");
 printf("\n Data : ");
  for(i=0;i<dl;i++)
  printf("%d",data1[i]);printf(" ");
   for(i=0;i<dl;i++)
  printf("%d",data2[i]);printf(" ");
   for(i=0;i<dl;i++)
  printf("%d",checksum[i]);

  printf("\n Addition : ");
  for(i=dl-1;i>=0;i--)
            {
            newdata[i]=add(newdata[i],checksum[i]);
            }
  for(i=0;i<dl;i++)
  {
   printf("%d",newdata[i]);
  }
  printf("\n  Compliment : ");
  for(i=0;i<dl;i++)
  {
   comp[i]=com(newdata[i]);
   printf("%d",comp[i]);
  }
}

int add(int x, int y)
{
static int carry=0;
 if(x==1 && y==1 && carry==0)
 {
 carry=1;
  return 0;
 }
 else if(x==1 && y==1 && carry==1)
 {
 carry=1;
 return 1;
 }
 else if(x==1 && y==0 && carry==0)
  {
  carry=0;
  return 1;
  }
  else if(x==1 && y==0 && carry==1)
  {
  carry=1;
  return 0;
  }
   else if(x==0 && y==1 && carry==0)
  {
  carry=0;
  return 1;
  }
  else if(x==0 && y==1 && carry==1)
  {
  carry=1;
  return 0;
  }
  else if(x==0 && y==0 && carry==0)
  {
  carry=0;
  return 0;
  }
  else
  {
  carry=0;
  return 1;
  }
}
int com(int a)
{
if(a==0)
return 1;
else
return 0;
}

//CHECKSUM IN PYTHON
//checksum - python

def findChecksum(SentMessage, k):

    # Dividing sent message in packets of k bits.
    c1 = SentMessage[0:k]
    c2 = SentMessage[k:2*k]
    c3 = SentMessage[2*k:3*k]
    c4 = SentMessage[3*k:4*k]

    # Calculating the binary sum of packets
    Sum = bin(int(c1, 2)+int(c2, 2)+int(c3, 2)+int(c4, 2))[2:]

    # Adding the overflow bits
    if(len(Sum) > k):
        x = len(Sum)-k
        Sum = bin(int(Sum[0:x], 2)+int(Sum[x:], 2))[2:]
    if(len(Sum) < k):
        Sum = '0'*(k-len(Sum))+Sum

    # Calculating the complement of sum
    Checksum = ''
    for i in Sum:
        if(i == '1'):
            Checksum += '0'
        else:
            Checksum += '1'
    return Checksum

# Function to find the Complement of binary addition of
# k bit packets of the Received Message + Checksum



# Driver Code
SentMessage = "10010101011000111001010011101100"
k = 8
#ReceivedMessage = "10000101011000111001010011101001"
ReceivedMessage = "10010101011000111001010011101000"
# Calling the findChecksum() function
Checksum = findChecksum(SentMessage, k)

# Calling the checkReceiverChecksum() function
ReceiverChecksum = findChecksum(ReceivedMessage, k)

# Printing Checksum
print("SENDER SIDE CHECKSUM: ", Checksum)
print("RECEIVER SIDE CHECKSUM: ", ReceiverChecksum)
if (Checksum == ReceiverChecksum):

    print("status:ACCEPTED")
else:
    print("status:ERROR DETECTED");
//





PACKET TRACER-"https://gofile.io/d/8nOa4Q"