From caef9ae333f640b4647fe5ebe253a5d4ae0213a5 Mon Sep 17 00:00:00 2001
From: Olaf Bohlen <olbohlen@eenfach.de>
Date: Tue, 29 Oct 2019 22:38:09 +0100
Subject: [PATCH] first public version
---
Makefile | 12 ++++++
tcp_server.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++
README.md | 2
3 files changed, 115 insertions(+), 1 deletions(-)
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..1f12bb1
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,12 @@
+CC=gcc
+#CFLAGS=-ansi -pedantic -Wall -lnsl -lsocket
+
+all: server
+
+server:
+ ${CC} ${CFLAGS} -o server tcp_server.c
+
+install:
+ mkdir -p /opt/app-root/bin
+ cp server /opt/app-root/bin
+ chmod 755 /opt/app-root/bin/server
diff --git a/README.md b/README.md
index a3925f2..74bf82d 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
## echo-server
-very simple TCP echo server
+simple tcp echo server
diff --git a/tcp_server.c b/tcp_server.c
new file mode 100644
index 0000000..9a6017a
--- /dev/null
+++ b/tcp_server.c
@@ -0,0 +1,102 @@
+/*********************
+ * simple TCP-server *
+ *********************/
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+
+int main(int argc, char **argv) {
+ unsigned short port; /* port to bind to */
+ char buffer[80]; /* i/o buffer */
+ struct sockaddr_in client; /* ip address of client */
+ struct sockaddr_in server; /* ip address of server */
+ struct hostent *hostnm; /* dest-hostname to connect to */
+ int s; /* socket */
+ int ns; /* socket connected to client */
+ int namelen; /* length of client name */
+ int optval=1;
+ int s_optlen=0;
+ ssize_t recvbytes; /* received bytes */
+
+ /* check for needed parameters */
+ if(argc!=3) {
+ fprintf(stderr, "%s portnumber\n", argv[0]);
+ exit(1);
+ }
+ hostnm=gethostbyname(argv[1]);
+
+ /* port to int */
+ port=(unsigned short) atoi(argv[2]);
+
+ /* generating socket */
+ if((s=socket(AF_INET, SOCK_STREAM,0))<0){
+ perror("Error:");
+ exit(2);
+ }
+
+ /* set socket options so that we can reuse the port */
+ setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &optval, s_optlen);
+
+ /* bind to socket */
+ server.sin_family = AF_INET;
+ server.sin_port = htons(port);
+ server.sin_addr.s_addr = *((unsigned long *)hostnm->h_addr);
+
+ if(bind(s, (struct sockaddr *)&server, sizeof(server))<0){
+ perror("Error:");
+ exit(3);
+ }
+
+ /* waiting for connections */
+ if(listen(s,1)!=0){
+ perror("Error:");
+ exit(4);
+ }
+
+ /* get connection */
+ namelen=sizeof(client);
+
+ /* we loop forever here to avoid stopping the server */
+ while(1) {
+ if((ns=accept(s, (struct sockaddr *)&client, &namelen))==-1){
+ perror("Error:");
+ exit(5);
+ }
+
+ /* write welcome banner to user */
+ snprintf(buffer, 54, "Welcome to the echo server, type a single x to quit.\n");
+ send(ns, buffer, 54, 0);
+ /* loop until we get an x as first char */
+ do {
+ /* get messages */
+ recvbytes=recv(ns, buffer, sizeof(buffer), 0);
+ if(recvbytes == -1){
+ perror("Error:");
+ exit(6);
+ }
+
+ /* send answer */
+ if(send(ns, buffer, recvbytes, 0) <0){
+ perror("Error:");
+ exit(7);
+ }
+ } while (buffer[0] != 'x');
+
+ /* client session closed on request, say bye bye */
+ snprintf(buffer, 30, "Good bye, see you next time.\n");
+ send(ns, buffer, 30, 0);
+
+ /* close connection */
+ close(ns);
+ }
+
+ /* close listener */
+ close(s);
+ printf("server exiting\n");
+ return(0);
+}
--
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