![TCP echo Server TCP echo Client
#include<stdio.h>
#include<netinet/in.h>
#include<netdb.h>
#define SERV_TCP_PORT 5035
int main(int argc,char**argv) {
int sockfd,newsockfd,clength;
struct sockaddr_in serv_addr,cli_addr;
char buffer[4096];
sockfd=socket(AF_INET,SOCK_STREAM,0);
serv_addr.sin_family=AF_INET;
serv_addr.sin_addr.s_addr=INADDR_ANY;
serv_addr.sin_port=htons(SERV_TCP_PORT);
printf("nStart");
bind(sockfd,(struct sockaddr*)&serv_addr,sizeof(serv_addr));
printf("nListening...");
listen(sockfd,5);
clength=sizeof(cli_addr);
newsockfd=accept(sockfd,(struct sockaddr*)&cli_addr,&clength);
printf("nAccepted");
read(newsockfd,buffer,4096);
printf("nClient message:%s",buffer);
write(newsockfd,buffer,4096);
close(sockfd);
return 0;
}
#include<stdio.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<netdb.h>
#define SERV_TCP_PORT 5035
int main(int argc,char*argv[]) {
int sockfd;
struct sockaddr_in serv_addr;
struct hostent *server;
char buffer[4096];
sockfd=socket(AF_INET,SOCK_STREAM,0);
serv_addr.sin_family=AF_INET;
serv_addr.sin_addr.s_addr=inet_addr("127.0.0.1");
serv_addr.sin_port=htons(SERV_TCP_PORT);
printf("nReady for sending...");
connect(sockfd,(struct sockaddr*) &serv_addr, sizeof(serv_addr));
printf("nEnter the message to sendn");
printf("nClient: ");
fgets(buffer,4096,stdin);
write(sockfd,buffer,4096);
printf("Serverecho:%s",buffer);
close(sockfd);
return 0;
}
#include<stdio.h>
#include<netinet/in.h>
#include<netdb.h>
#define SERV_TCP_PORT 5035
int main(int argc,char**argv) {
int sockfd,newsockfd,clength;
struct sockaddr_in serv_addr,cli_addr;
char buffer[4096];
sockfd=socket(AF_INET,SOCK_STREAM,0);
serv_addr.sin_family=AF_INET;
serv_addr.sin_addr.s_addr=INADDR_ANY;
serv_addr.sin_port=htons(SERV_TCP_PORT);
printf("nStart");
bind(sockfd,(struct sockaddr*)&serv_addr,sizeof(serv_addr));
printf("nListening...");
listen(sockfd,5);
clength=sizeof(cli_addr);
newsockfd=accept(sockfd,(struct sockaddr*)&cli_addr,&clength);
printf("nAccepted");
read(newsockfd,buffer,4096);
printf("nClient message:%s",buffer);
write(newsockfd,buffer,4096);
close(sockfd);
return 0;
}
#include<stdio.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<netdb.h>
#define SERV_TCP_PORT 5035
int main(int argc,char*argv[]) {
int sockfd;
struct sockaddr_in serv_addr;
struct hostent *server;
char buffer[4096];
sockfd=socket(AF_INET,SOCK_STREAM,0);
serv_addr.sin_family=AF_INET;
serv_addr.sin_addr.s_addr=inet_addr("127.0.0.1");
serv_addr.sin_port=htons(SERV_TCP_PORT);
printf("nReady for sending...");
connect(sockfd,(struct sockaddr*) &serv_addr, sizeof(serv_addr));
printf("nEnter the message to sendn");
printf("nClient: ");
fgets(buffer,4096,stdin);
write(sockfd,buffer,4096);
printf("Serverecho:%s",buffer);
close(sockfd);
return 0;
}](https://image.slidesharecdn.com/socket-241014044851-184d8deb/85/socketProgramming-TCP-and-UDP-overview-pdf-11-320.jpg)
socketProgramming-TCP-and UDP-overview.pdf
- 2. TCP Sockets
- 3. UDP Sockets
- 4. Socket int s = socket(domain, type, protocol); where s: socket descriptor, an integer (like a file-handle) domain: integer, communication domain e.g.,AF_INET (IPv4 protocol) or AF_UNIX type: communication type SOCK_STREAM: reliable, 2-way, connection-based service SOCK_DGRAM: unreliable, connectionless protocol: e.g.,TCP or UDP use IPPROTO_TCP or IPPROTO_UDP to send/receiveTCP or UDP packets Example : s = socket(AF_INET, SOCK_STREAM, 0); int s = socket(domain, type, protocol); where s: socket descriptor, an integer (like a file-handle) domain: integer, communication domain e.g.,AF_INET (IPv4 protocol) or AF_UNIX type: communication type SOCK_STREAM: reliable, 2-way, connection-based service SOCK_DGRAM: unreliable, connectionless protocol: e.g.,TCP or UDP use IPPROTO_TCP or IPPROTO_UDP to send/receiveTCP or UDP packets Example : s = socket(AF_INET, SOCK_STREAM, 0);
- 5. Bind associates an IP address and port for use by the socket int status = bind(s, &addrport, size) status: return status, 0 if successful, -1 otherwise s: socket being used addrport: address structure uses sockaddr_in size: the size (in bytes) of the addrport structure struct sockaddr_in { sa_family_t sin_family; /* address family:AF_INET */ u_int16_t sin_port; /* port in network byte order */ struct in_addr sin_addr; /* internet address */ }; struct in_addr /* Internet address */ { u_int32_t s_addr; /* address in network byte order */ }; associates an IP address and port for use by the socket int status = bind(s, &addrport, size) status: return status, 0 if successful, -1 otherwise s: socket being used addrport: address structure uses sockaddr_in size: the size (in bytes) of the addrport structure struct sockaddr_in { sa_family_t sin_family; /* address family:AF_INET */ u_int16_t sin_port; /* port in network byte order */ struct in_addr sin_addr; /* internet address */ }; struct in_addr /* Internet address */ { u_int32_t s_addr; /* address in network byte order */ };
- 6. Listen The listen system call allows the process to listen on the socket for connections. int status = listen(s, queuelen) status: return value, 0 if listening, -1 if error s: socket being used queuelen: number of active participants that can “wait” for a connection Example : listen(s, 5); The listen system call allows the process to listen on the socket for connections. int status = listen(s, queuelen) status: return value, 0 if listening, -1 if error s: socket being used queuelen: number of active participants that can “wait” for a connection Example : listen(s, 5);
- 7. accept Use the accept function to accept a connection request from a remote host The function returns a socket corresponding to the accepted connection int ns = accept(sock, &cliaddr, &addrlen) ns: new socket used for data-transfer sock: original socket being listened on (e.g., server) cliaddr: address structure of the active participant (e.g., client) The accept function updates/returns the sockaddr structure with the client's address information addrlen: size (in bytes) of the client sockaddr structure The accept function updates/returns this value Use the accept function to accept a connection request from a remote host The function returns a socket corresponding to the accepted connection int ns = accept(sock, &cliaddr, &addrlen) ns: new socket used for data-transfer sock: original socket being listened on (e.g., server) cliaddr: address structure of the active participant (e.g., client) The accept function updates/returns the sockaddr structure with the client's address information addrlen: size (in bytes) of the client sockaddr structure The accept function updates/returns this value
- 8. Connect The connect function is used by a client program to establish communication with a remote entity int status = connect(sock, &servaddr, addrlen); status: return value, 0 if successful connect, -1 otherwise sock: client’s socket to be used in connection servaddr: server’s address structure addrlen: size (in bytes) of the servaddr structure The connect function is used by a client program to establish communication with a remote entity int status = connect(sock, &servaddr, addrlen); status: return value, 0 if successful connect, -1 otherwise sock: client’s socket to be used in connection servaddr: server’s address structure addrlen: size (in bytes) of the servaddr structure
- 9. Sending / Receiving Data Send data int count = send(int s, const void * msg, int len, unsigned int falgs); Where: count: number of bytes transmitted (-1 if error) sock: socket being used buf: buffer to be transmitted len: length of buffer (in bytes) to transmit flags: special options, usually just 0 Receive data int count = recv(int s, void *buf, int len, unsigned int flags); Where: count: number of bytes received (-1 if error) sock: socket being used buf: stores received bytes len: number of bytes received flags: special options, usually just 0 Send data int count = send(int s, const void * msg, int len, unsigned int falgs); Where: count: number of bytes transmitted (-1 if error) sock: socket being used buf: buffer to be transmitted len: length of buffer (in bytes) to transmit flags: special options, usually just 0 Receive data int count = recv(int s, void *buf, int len, unsigned int flags); Where: count: number of bytes received (-1 if error) sock: socket being used buf: stores received bytes len: number of bytes received flags: special options, usually just 0
- 10. close When finished using a socket, the socket should be closed: status = close(s); status: return value, 0 if successful, -1 if error s: the file descriptor (socket being closed)
- 11. TCP echo Server TCP echo Client #include<stdio.h> #include<netinet/in.h> #include<netdb.h> #define SERV_TCP_PORT 5035 int main(int argc,char**argv) { int sockfd,newsockfd,clength; struct sockaddr_in serv_addr,cli_addr; char buffer[4096]; sockfd=socket(AF_INET,SOCK_STREAM,0); serv_addr.sin_family=AF_INET; serv_addr.sin_addr.s_addr=INADDR_ANY; serv_addr.sin_port=htons(SERV_TCP_PORT); printf("nStart"); bind(sockfd,(struct sockaddr*)&serv_addr,sizeof(serv_addr)); printf("nListening..."); listen(sockfd,5); clength=sizeof(cli_addr); newsockfd=accept(sockfd,(struct sockaddr*)&cli_addr,&clength); printf("nAccepted"); read(newsockfd,buffer,4096); printf("nClient message:%s",buffer); write(newsockfd,buffer,4096); close(sockfd); return 0; } #include<stdio.h> #include<sys/types.h> #include<sys/socket.h> #include<netinet/in.h> #include<netdb.h> #define SERV_TCP_PORT 5035 int main(int argc,char*argv[]) { int sockfd; struct sockaddr_in serv_addr; struct hostent *server; char buffer[4096]; sockfd=socket(AF_INET,SOCK_STREAM,0); serv_addr.sin_family=AF_INET; serv_addr.sin_addr.s_addr=inet_addr("127.0.0.1"); serv_addr.sin_port=htons(SERV_TCP_PORT); printf("nReady for sending..."); connect(sockfd,(struct sockaddr*) &serv_addr, sizeof(serv_addr)); printf("nEnter the message to sendn"); printf("nClient: "); fgets(buffer,4096,stdin); write(sockfd,buffer,4096); printf("Serverecho:%s",buffer); close(sockfd); return 0; } #include<stdio.h> #include<netinet/in.h> #include<netdb.h> #define SERV_TCP_PORT 5035 int main(int argc,char**argv) { int sockfd,newsockfd,clength; struct sockaddr_in serv_addr,cli_addr; char buffer[4096]; sockfd=socket(AF_INET,SOCK_STREAM,0); serv_addr.sin_family=AF_INET; serv_addr.sin_addr.s_addr=INADDR_ANY; serv_addr.sin_port=htons(SERV_TCP_PORT); printf("nStart"); bind(sockfd,(struct sockaddr*)&serv_addr,sizeof(serv_addr)); printf("nListening..."); listen(sockfd,5); clength=sizeof(cli_addr); newsockfd=accept(sockfd,(struct sockaddr*)&cli_addr,&clength); printf("nAccepted"); read(newsockfd,buffer,4096); printf("nClient message:%s",buffer); write(newsockfd,buffer,4096); close(sockfd); return 0; } #include<stdio.h> #include<sys/types.h> #include<sys/socket.h> #include<netinet/in.h> #include<netdb.h> #define SERV_TCP_PORT 5035 int main(int argc,char*argv[]) { int sockfd; struct sockaddr_in serv_addr; struct hostent *server; char buffer[4096]; sockfd=socket(AF_INET,SOCK_STREAM,0); serv_addr.sin_family=AF_INET; serv_addr.sin_addr.s_addr=inet_addr("127.0.0.1"); serv_addr.sin_port=htons(SERV_TCP_PORT); printf("nReady for sending..."); connect(sockfd,(struct sockaddr*) &serv_addr, sizeof(serv_addr)); printf("nEnter the message to sendn"); printf("nClient: "); fgets(buffer,4096,stdin); write(sockfd,buffer,4096); printf("Serverecho:%s",buffer); close(sockfd); return 0; }
- 12. END END