Add example tcp connection

src/CMakeLists.txt

@@ -39,7 +39,7 @@ SET(SOURCES
 	crypto/base64.c
 	include/base64.h
 
-	utils/utils.c)
+	utils/utils.c include/tcpsocket.h network/tcpsocket.c)
 
 SET(LIBS
 	ubox ubus json-c blobmsg_json config uci gcrypt ssl crypto)

src/include/tcpsocket.h

@@ -0,0 +1,19 @@
+//
+// Created by nick on 19.09.17.
+//
+
+#ifndef DAWN_TCPSOCKET_H
+#define DAWN_TCPSOCKET_H
+
+#include <netinet/in.h>
+
+int run_tcp_socket();
+int add_tcp_conncection(char* ipv4, int port);
+
+struct network_con_s
+{
+    int sockfd;
+    struct sockaddr_in sock_addr;
+};
+
+#endif //DAWN_TCPSOCKET_H

src/main.c

@@ -14,6 +14,7 @@
 #include "networksocket.h"
 #include "ubus.h"
 #include "dawn_uci.h"
+#include "tcpsocket.h"
 
 #define BUFSIZE 17
 #define BUFSIZE_DIR 256
@@ -170,6 +171,8 @@ int main(int argc, char **argv) {
         }
     }
 
+    run_tcp_socket();
+
     argc -= optind;
     argv += optind;
 

src/network/tcpsocket.c

@@ -0,0 +1,196 @@
+//
+// Created by nick on 19.09.17.
+//
+
+// http://www.geeksforgeeks.org/socket-programming-in-cc-handling-multiple-clients-on-server-without-multi-threading/
+
+#include "tcpsocket.h"
+
+//Example code: A simple server side code, which echos back the received message.
+//Handle multiple socket connections with select and fd_set on Linux
+#include <stdio.h>
+#include <string.h>   //strlen
+#include <stdlib.h>
+#include <errno.h>
+#include <unistd.h>   //close
+#include <arpa/inet.h>    //close
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <sys/time.h> //FD_SET, FD_ISSET, FD_ZERO macros
+
+#define TRUE   1
+#define FALSE  0
+#define PORT 1025
+
+//struct network_con_s connections[100];
+//int tcp_entry_last = -1;
+
+int run_tcp_socket()
+{
+    int opt = TRUE;
+    int master_socket, addrlen, new_socket, client_socket[30],
+            max_clients = 30, activity, i, valread, sd;
+    int max_sd;
+    struct sockaddr_in address;
+
+    char buffer[1025];  //data buffer of 1K
+
+    //set of socket descriptors
+    fd_set readfds;
+
+    char *message = "ECHO Daemon v1.0 \r\n";
+
+    //initialise all client_socket[] to 0 so not checked
+    for (i = 0; i < max_clients; i++) {
+        client_socket[i] = 0;
+    }
+
+    //create a master socket
+    if ((master_socket = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
+        perror("socket failed");
+        exit(EXIT_FAILURE);
+    }
+
+    //set master socket to allow multiple connections ,
+    //this is just a good habit, it will work without this
+    if (setsockopt(master_socket, SOL_SOCKET, SO_REUSEADDR, (char *) &opt,
+                   sizeof(opt)) < 0) {
+        perror("setsockopt");
+        exit(EXIT_FAILURE);
+    }
+
+    //type of socket created
+    address.sin_family = AF_INET;
+    address.sin_addr.s_addr = INADDR_ANY;
+    address.sin_port = htons(PORT);
+
+    //bind the socket to localhost port 8888
+    if (bind(master_socket, (struct sockaddr *) &address, sizeof(address)) < 0) {
+        perror("bind failed");
+        exit(EXIT_FAILURE);
+    }
+    printf("Listener on port %d \n", PORT);
+
+    //try to specify maximum of 3 pending connections for the master socket
+    if (listen(master_socket, 3) < 0) {
+        perror("listen");
+        exit(EXIT_FAILURE);
+    }
+
+    //accept the incoming connection
+    addrlen = sizeof(address);
+    puts("Waiting for connections ...");
+
+    while (TRUE) {
+        //clear the socket set
+        FD_ZERO(&readfds);
+
+        //add master socket to set
+        FD_SET(master_socket, &readfds);
+        max_sd = master_socket;
+
+        //add child sockets to set
+        for (i = 0; i < max_clients; i++) {
+            //socket descriptor
+            sd = client_socket[i];
+
+            //if valid socket descriptor then add to read list
+            if (sd > 0)
+                FD_SET(sd, &readfds);
+
+            //highest file descriptor number, need it for the select function
+            if (sd > max_sd)
+                max_sd = sd;
+        }
+
+        //wait for an activity on one of the sockets , timeout is NULL ,
+        //so wait indefinitely
+        activity = select(max_sd + 1, &readfds, NULL, NULL, NULL);
+
+        if ((activity < 0) && (errno != EINTR)) {
+            printf("select error");
+        }
+
+        //If something happened on the master socket ,
+        //then its an incoming connection
+        if (FD_ISSET(master_socket, &readfds)) {
+            if ((new_socket = accept(master_socket,
+                                     (struct sockaddr *) &address, (socklen_t *) &addrlen)) < 0) {
+                perror("accept");
+                exit(EXIT_FAILURE);
+            }
+
+            //inform user of socket number - used in send and receive commands
+            printf("New connection , socket fd is %d , ip is : %s , port : %d\n", new_socket,
+                   inet_ntoa(address.sin_addr), ntohs
+                   (address.sin_port));
+
+            //send new connection greeting message
+            if (send(new_socket, message, strlen(message), 0) != strlen(message)) {
+                perror("send");
+            }
+
+            puts("Welcome message sent successfully");
+
+            //add new socket to array of sockets
+            for (i = 0; i < max_clients; i++) {
+                //if position is empty
+                if (client_socket[i] == 0) {
+                    client_socket[i] = new_socket;
+                    printf("Adding to list of sockets as %d\n", i);
+
+                    break;
+                }
+            }
+        }
+
+        //else its some IO operation on some other socket
+        for (i = 0; i < max_clients; i++) {
+            sd = client_socket[i];
+
+            if (FD_ISSET(sd, &readfds)) {
+                //Check if it was for closing , and also read the
+                //incoming message
+                if ((valread = read(sd, buffer, 1024)) == 0) {
+                    //Somebody disconnected , get his details and print
+                    getpeername(sd, (struct sockaddr *) &address, \
+                        (socklen_t *) &addrlen);
+                    printf("Host disconnected , ip %s , port %d \n",
+                           inet_ntoa(address.sin_addr), ntohs(address.sin_port));
+
+                    //Close the socket and mark as 0 in list for reuse
+                    close(sd);
+                    client_socket[i] = 0;
+                }
+
+                    //Echo back the message that came in
+                else {
+                    //set the string terminating NULL byte on the end
+                    //of the data read
+                    buffer[valread] = '\0';
+                    send(sd, buffer, strlen(buffer), 0);
+                }
+            }
+        }
+    }
+    return 0;
+}
+
+int add_tcp_conncection(char* ipv4, int port){
+    int sockfd;
+    struct sockaddr_in serv_addr;
+    sockfd = socket(AF_INET, SOCK_STREAM, 0);
+    if (sockfd < 0)
+        fprintf(stderr,"ERROR opening socket");
+
+    memset(&serv_addr, 0, sizeof(serv_addr));
+    serv_addr.sin_family = AF_INET;
+    serv_addr.sin_addr.s_addr = inet_addr(ipv4);
+    serv_addr.sin_port = htons(port);
+
+    if (connect(sockfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) < 0)
+        fprintf(stderr,"ERROR connecting");
+    return 0;
+}
+