add client testing

include/client.h

@@ -0,0 +1,16 @@
+#ifndef __CLIENT_H__
+#define __CLIENT_H__
+
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int test_client_connection(const char *hostname, const char *port);
+
+#endif

include/server.h

@@ -15,6 +15,6 @@
 // how many pending connections the queue will hold
 #define BACKLOG 10
 
-int start_server(void);
+int start_server(const char *hostname, const char *service);
 
 #endif

include/utils.h

@@ -11,7 +11,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-// Print every IPs of a hostname
+// print every IPs of a hostname
 void print_ips(const char *hostname, const char *port);
 
 #endif

meson.build

@@ -1,6 +1,7 @@
-project('tutorial', 'c')
+project('cws', 'c')
 
 subdir('src')
 incdir = include_directories('include')
 
-executable('cws', sources, include_directories: incdir)
+executable('server', server, include_directories: incdir)
+executable('client', client, include_directories: incdir)

notes/basic-concepts.md

@@ -12,6 +12,12 @@ Before reading, this document could contain errors, please check everything you
       - [struct sockaddr\_storage](#struct-sockaddr_storage)
     - [IP Addresses](#ip-addresses)
     - [getaddrinfo()](#getaddrinfo)
+    - [socket()](#socket-1)
+    - [bind()](#bind)
+    - [connect()](#connect)
+    - [listen()](#listen)
+    - [accept()](#accept)
+    - [send() and recv()](#send-and-recv)
 
 
 ### Socket
@@ -116,3 +122,43 @@ int getaddrinfo(const char *node,     // e.g. "www.example.com" or IP
 
 The `node` could be a host name or IP address. `service` could be a port number or a service found in `/etc/services` (e.g. "http" or "ftp" or "telnet").
 `hints` points to a struct you already filled and `res` contains a linked list of results.
+
+### socket()
+```c
+int socket(int domain, int type, int protocol); 
+```
+
+`domain` could be `PF_INET` or `PF_INET6`, `type` instead TCP or UDP and `protocol` to 0. `PF_INET` is very close to `AF_INET`! However, we can avoid to put the stuff manually and use the results from `getaddrinfo()`.
+
+### bind()
+Do this if you're going to listen on a port. The port is used by the kernel to match an incoming packet to a socket descriptor.
+
+```c
+int bind(int sockfd, struct sockaddr *my_addr, int addrlen);
+```
+
+### connect()
+```c
+int connect(int sockfd, struct sockaddr *serv_addr, int addrlen); 
+```
+
+### listen()
+```c
+int listen(int sockfd, int backlog);
+```
+
+`backlog` is the amount of max clients allowed on the incoming queue. A client will wait in the queue until you accept it.
+
+### accept()
+```c
+int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen);
+```
+
+After you accept a client, the function will return a new socket file descriptor used to communicate.
+
+### send() and recv()
+```c
+int send(int sockfd, const void *msg, int len, int flags); 
+```
+
+Just put `flags` to 0. It will return the bytes sent.

src/client.c

@@ -0,0 +1,38 @@
+// THIS FILE IS ONLY A TEST FOR THE BASIC STUFF
+
+#include "client.h"
+#include "colors.h"
+
+int test_client_connection(const char *hostname, const char *port) {
+	struct addrinfo hints;
+	struct addrinfo *res;
+
+	memset(&hints, 0, sizeof hints);
+	hints.ai_socktype = SOCK_STREAM;
+	hints.ai_family = AF_INET;
+
+	int status = getaddrinfo(hostname, port, &hints, &res);
+	if (status != 0) {
+		fprintf(stderr, RED BOLD "[client] getaddrinfo(): %s\n" RESET,
+			gai_strerror(status));
+		exit(EXIT_FAILURE);
+	}
+
+	int sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
+
+	status = connect(sockfd, res->ai_addr, res->ai_addrlen);
+	if (status != 0) {
+		fprintf(stderr, RED BOLD "[client] connect(): %s\n" RESET,
+			gai_strerror(status));
+		exit(EXIT_FAILURE);
+	}
+
+	char buf[4096];
+	int bytes_read = recv(sockfd, buf, 4096, 0);
+	fprintf(stdout, BLUE "[client] Read %d bytes: %s\n" RESET, bytes_read,
+		buf);
+
+	freeaddrinfo(res);
+
+	return 0;
+}

src/main.c

@@ -1,17 +1,14 @@
 #include "main.h"
 #include "colors.h"
 #include "server.h"
-#include "utils.h"
 
 int main(int argc, char **argv) {
-	fprintf(stdout, BOLD GREEN "Running cws...\n" RESET);
+	fprintf(stdout, BOLD GREEN "[server] Running cws...\n" RESET);
 
-	int ret = start_server();
+	int ret = start_server(NULL, "3030");
 	if (ret < 0) {
 		fprintf(stderr, BOLD RED "Unable to start web server\n");
 	}
 
-	print_ips("google.com", "80");
-
 	return 0;
 }

src/mainc.c

@@ -0,0 +1,14 @@
+#include "client.h"
+#include "colors.h"
+#include "main.h"
+
+int main(int argc, char **argv) {
+	fprintf(stdout, BOLD GREEN "[client] Running cws...\n" RESET);
+
+	int ret = test_client_connection("localhost", "3030");
+	if (ret < 0) {
+		fprintf(stderr, BOLD RED "Unable to start client\n");
+	}
+
+	return 0;
+}

src/meson.build

@@ -1 +1,2 @@
-sources = files('main.c', 'server.c', 'utils.c')
+server = files('main.c', 'server.c', 'utils.c')
+client = files('mainc.c', 'client.c')

src/server.c

@@ -1,34 +1,49 @@
 #include "server.h"
 #include "colors.h"
 
-int start_server(void) {
-	char ipv4[INET_ADDRSTRLEN];
-	struct sockaddr_in sa;
-
-	inet_pton(AF_INET, "192.168.0.1", &(sa.sin_addr));
-	inet_ntop(AF_INET, &(sa.sin_addr), ipv4, INET_ADDRSTRLEN);
-
-	fprintf(stdout, BLUE "IPv4: %s\n" RESET, ipv4);
-
-	return 0;
-}
-
-void get_local_ip(void) {
-	char service[] = "3030";
+int start_server(const char *hostname, const char *service) {
 	struct addrinfo hints;
 	struct addrinfo *res;
+	struct sockaddr_storage their_sa; // incoming clients
+	socklen_t theirsa_size = sizeof their_sa;
 
 	memset(&hints, 0, sizeof hints);
 	hints.ai_family = AF_UNSPEC;	 // IPv4 or IPv6
 	hints.ai_socktype = SOCK_STREAM; // TCP
 	hints.ai_flags = AI_PASSIVE;	 // fill in IP for me
 
-	int status = getaddrinfo(NULL, service, &hints, &res);
+	int status = getaddrinfo(hostname, service, &hints, &res);
 	if (status != 0) {
-		fprintf(stderr, RED "getaddrinfo() error: %s\n" RESET,
+		fprintf(stderr,
+			RED BOLD "[server] getaddrinfo() error: %s\n" RESET,
 			gai_strerror(status));
-		exit(1);
+		exit(EXIT_FAILURE);
 	}
 
+	// socket file descriptor
+	int sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
+
+	status = bind(sockfd, res->ai_addr, res->ai_addrlen);
+	if (status != 0) {
+		fprintf(stderr, RED BOLD "[server] bind(): %s\n" RESET,
+			gai_strerror(status));
+		exit(EXIT_FAILURE);
+	}
+
+	status = listen(sockfd, BACKLOG);
+	if (status != 0) {
+		fprintf(stderr, RED BOLD "[server] listen(): %s\n" RESET,
+			gai_strerror(status));
+		exit(EXIT_FAILURE);
+	}
+
+	char *msg = "Hello there!";
+	int msg_len = strlen(msg);
+	int newfd = accept(sockfd, (struct sockaddr *)&their_sa, &theirsa_size);
+	int bytes_sent = send(newfd, msg, msg_len, 0);
+	fprintf(stdout, BLUE "[server] Sent %d bytes\n" RESET, bytes_sent);
+
 	freeaddrinfo(res);
+
+	return 0;
 }