Use non-blocking socket for EthernetServer

* Non-blocking socket

To simplify the class design and better mimics the Arduino version

* Doxygenize EthernetServer class

drivers/Linux/EthernetServer.cpp

@@ -23,25 +23,14 @@
 #include <sys/socket.h>
 #include <cstring>
 #include <sys/socket.h>
-#include <pthread.h>
 #include <netdb.h>
 #include <arpa/inet.h>
 #include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include "EthernetClient.h"
 #include "EthernetServer.h"
 
-struct server_vars {
-	uint16_t port;
-	struct IPAddress address;
-	std::list<int> *new_clients;
-	std::vector<int> *clients;
-	uint16_t max_clients;
-};
-
-static pthread_mutex_t new_clients_mutex = PTHREAD_MUTEX_INITIALIZER;
-static pthread_mutex_t clients_mutex = PTHREAD_MUTEX_INITIALIZER;
-
-void *incoming_connections(void *);
-
 EthernetServer::EthernetServer(uint16_t port, uint16_t max_clients) : port(port), max_clients(max_clients)
 {
 	clients.reserve(max_clients);
@@ -54,104 +43,7 @@ void EthernetServer::begin()
 
 void EthernetServer::begin(IPAddress address)
 {
-	pthread_t thread_id;
-	pthread_attr_t detached_attr;
-
-	struct server_vars *vars = new struct server_vars;
-	vars->port = port;
-	vars->address = address;
-	vars->new_clients = &new_clients;
-	vars->clients = &clients;
-	vars->max_clients = max_clients;
-
-	pthread_attr_init(&detached_attr);
-	pthread_attr_setdetachstate(&detached_attr, PTHREAD_CREATE_DETACHED);
-	pthread_create(&thread_id, &detached_attr, &incoming_connections, vars);
-}
-
-void EthernetServer::beginPacket(IPAddress address, uint16_t port)
-{
-	//TODO: UDP
-	(void)address;
-	(void)port;
-}
-
-int EthernetServer::parsePacket()
-{
-	//TODO: UDP
-
-	return 0;
-}
-
-bool EthernetServer::hasClient()
-{
-	bool empty;
-
-	pthread_mutex_lock(&new_clients_mutex);
-	empty = new_clients.empty();
-	pthread_mutex_unlock(&new_clients_mutex);
-
-	return !empty;
-}
-
-EthernetClient EthernetServer::available()
-{
-	int sock;
-
-	pthread_mutex_lock(&new_clients_mutex);
-	if (new_clients.empty()) {
-		sock = -1;
-	} else {
-		sock = new_clients.front();
-		new_clients.pop_front();
-	}
-	pthread_mutex_unlock(&new_clients_mutex);
-
-	return EthernetClient(sock);
-}
-
-size_t EthernetServer::write(uint8_t b) 
-{
-	return write(&b, 1);
-}
-
-size_t EthernetServer::write(const uint8_t *buffer, size_t size) 
-{
-	size_t n = 0;
-	size_t i = 0;
-
-	pthread_mutex_lock(&clients_mutex);
-	while (i < clients.size()) {
-		EthernetClient client(clients[i]);
-		if (client.connected()) {
-			n += client.write(buffer, size);
-			i++;
-		} else {
-			clients[i] = clients.back();
-			clients.pop_back();
-		}
-	}
-	pthread_mutex_unlock(&clients_mutex);
-
-	return n;
-}
-
-size_t EthernetServer::write(const char *str) {
-	if (str == NULL) return 0;
-	return write((const uint8_t *)str, strlen(str));
-}
-
-size_t EthernetServer::write(const char *buffer, size_t size) {
-	return write((const uint8_t *)buffer, size);
-}
-
-void *incoming_connections(void* thread_arg)
-{
-	struct server_vars *vars = (struct server_vars*) thread_arg;
-	int sockfd, new_fd;
 	struct addrinfo hints, *servinfo, *p;
-	struct sockaddr_storage client_addr;
-	socklen_t sin_size;
 	int yes=1;
 	int rv;
 	char ipstr[INET_ADDRSTRLEN];
@@ -162,10 +54,10 @@ void *incoming_connections(void* thread_arg)
 	hints.ai_socktype = SOCK_STREAM;
 	hints.ai_flags = AI_PASSIVE;
 
-	sprintf(portstr, "%d", vars->port);
-	if ((rv = getaddrinfo(vars->address.toString().c_str(), portstr, &hints, &servinfo)) != 0) {
+	sprintf(portstr, "%d", port);
+	if ((rv = getaddrinfo(address.toString().c_str(), portstr, &hints, &servinfo)) != 0) {
 		fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
-		return NULL;
+		return;
 	}
 
 	// loop through all the results and bind to the first we can
@@ -178,7 +70,7 @@ void *incoming_connections(void* thread_arg)
 		if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) {
 			perror("setsockopt");
 			freeaddrinfo(servinfo);
-			return NULL;
+			return;
 		}
 
 		if (bind(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
@@ -193,53 +85,130 @@ void *incoming_connections(void* thread_arg)
 	if (p == NULL)  {
 		fprintf(stderr, "failed to bind\n");
 		freeaddrinfo(servinfo);
-		return NULL;
+		return;
 	}
 
 	if (listen(sockfd, ETHERNETSERVER_BACKLOG) == -1) {
 		perror("listen");
 		freeaddrinfo(servinfo);
-		return NULL;
+		return;
 	}
 
 	freeaddrinfo(servinfo);
 
+	fcntl(sockfd, F_SETFL, O_NONBLOCK);
+
 	struct sockaddr_in *ipv4 = (struct sockaddr_in *)p->ai_addr;
 	void *addr = &(ipv4->sin_addr);
 	inet_ntop(p->ai_family, addr, ipstr, sizeof ipstr);
 	ETHERNETSERVER_DEBUG("Listening for connections on %s:%s\n", ipstr, portstr);
+}
 
-	while (1) {  // accept() loop
-		sin_size = sizeof client_addr;
-		new_fd = accept(sockfd, (struct sockaddr *)&client_addr, &sin_size);
-		if (new_fd == -1) {
-			perror("accept");
-			continue;
-		}
+bool EthernetServer::hasClient()
+{
+	_accept();
 
-		void *addr = &(((struct sockaddr_in*)&client_addr)->sin_addr);
-		inet_ntop(client_addr.ss_family, addr, ipstr, sizeof ipstr);
-		ETHERNETSERVER_DEBUG("New connection from %s\n", ipstr);
+	return !new_clients.empty();
+}
 
-		pthread_mutex_lock(&new_clients_mutex);
-		pthread_mutex_lock(&clients_mutex);
-		int connected_clients = vars->new_clients->size() + vars->clients->size();
+EthernetClient EthernetServer::available()
+{
+	if (new_clients.empty()) {
+		return EthernetClient();
+	} else {
+		int sock = new_clients.front();
+		new_clients.pop_front();
+		return EthernetClient(sock);
+	}
+}
 
-		if (connected_clients == vars->max_clients) {
-			pthread_mutex_unlock(&clients_mutex);
-			pthread_mutex_unlock(&new_clients_mutex);
-			ETHERNETSERVER_DEBUG("Max number of ethernet clients reached.");
-			close(new_fd);
-			usleep(5000000);
-		} else {
-			vars->new_clients->push_back(new_fd);
-			vars->clients->push_back(new_fd);
-			pthread_mutex_unlock(&clients_mutex);
-			pthread_mutex_unlock(&new_clients_mutex);
+size_t EthernetServer::write(uint8_t b)
+{
+	return write(&b, 1);
+}
+
+size_t EthernetServer::write(const uint8_t *buffer, size_t size)
+{
+	size_t n = 0;
+	size_t i = 0;
+
+	while (i < clients.size()) {
+		EthernetClient client(clients[i]);
+		if (client.connected()) {
+			n += client.write(buffer, size);
+			i++;
+		} else if (!client.available()) {
+			client.stop();
+			clients[i] = clients.back();
+			clients.pop_back();
+			ETHERNETSERVER_DEBUG("Client disconnected.");
 		}
 	}
 
-	delete vars;
+	return n;
+}
 
-	return NULL;
+size_t EthernetServer::write(const char *str)
+{
+	if (str == NULL) return 0;
+	return write((const uint8_t *)str, strlen(str));
+}
+
+size_t EthernetServer::write(const char *buffer, size_t size)
+{
+	return write((const uint8_t *)buffer, size);
+}
+
+void EthernetServer::_accept()
+{
+	int new_fd;
+	socklen_t sin_size;
+	struct sockaddr_storage client_addr;
+	char ipstr[INET_ADDRSTRLEN];
+
+	if (new_clients.size() + clients.size() == max_clients) {
+		// no free slots, search for a dead client
+		bool no_free_slots = true;
+		for (size_t i = 0; i < clients.size();) {
+			EthernetClient client(clients[i]);
+			if (client.connected() || client.available()) {
+				i++;
+			} else {
+				clients[i] = clients.back();
+				clients.pop_back();
+				no_free_slots = false;
+				break;
+			}
+		}
+		if (no_free_slots) {
+			for (std::list<int>::iterator it = new_clients.begin(); it != new_clients.end(); ++it) {
+				EthernetClient client(*it);
+				if (!client.connected() && !client.available()) {
+					new_clients.erase(it);
+					no_free_slots = false;
+					break;
+				}
+			}
+		}
+		if (no_free_slots) {
+			ETHERNETSERVER_DEBUG("Max number of ethernet clients reached.");
+			return;
+		}
+	}
+
+	sin_size = sizeof client_addr;
+	new_fd = accept(sockfd, (struct sockaddr *)&client_addr, &sin_size);
+	if (new_fd == -1) {
+		if (errno != EAGAIN && errno != EWOULDBLOCK) {
+			perror("accept");
+		}
+		return;
+	}
+
+	new_clients.push_back(new_fd);
+	clients.push_back(new_fd);
+
+	void *addr = &(((struct sockaddr_in*)&client_addr)->sin_addr);
+	inet_ntop(client_addr.ss_family, addr, ipstr, sizeof ipstr);
+	ETHERNETSERVER_DEBUG("New connection from %s\n", ipstr);
 }

drivers/Linux/EthernetServer.h

@@ -25,44 +25,102 @@
 #include <list>
 #include <vector>
 #include "Server.h"
-#include "EthernetClient.h"
+#include "IPAddress.h"
 
-#ifndef ETHERNETSERVER_BACKLOG
-	#define ETHERNETSERVER_BACKLOG 10
-#endif
-
-#ifndef ETHERNETSERVER_MAX_CLIENTS
-	#define ETHERNETSERVER_MAX_CLIENTS ETHERNETSERVER_BACKLOG
+#ifdef ETHERNETSERVER_MAX_CLIENTS
+	#define ETHERNETSERVER_BACKLOG ETHERNETSERVER_MAX_CLIENTS //!< Maximum length to which the queue of pending connections may grow.
+#else
+	#define ETHERNETSERVER_MAX_CLIENTS 10 //!< Default value for max_clients.
+	#define ETHERNETSERVER_BACKLOG 10 //!< Maximum length to which the queue of pending connections may grow.
 #endif
 
 // debug 
 #if defined(ETHERNETSERVER_VERBOSE)
-	#define ETHERNETSERVER_DEBUG(x,...) debug(x, ##__VA_ARGS__)
+	#define ETHERNETSERVER_DEBUG(x,...) printf(x, ##__VA_ARGS__) //!< debug
 #else
-	#define ETHERNETSERVER_DEBUG(x,...)
+	#define ETHERNETSERVER_DEBUG(x,...) //!< debug NULL
 #endif
 
 class EthernetClient;
 
+/**
+ * @brief EthernetServer class
+ */
 class EthernetServer : public Server {
 
 private:
-	uint16_t port;
-	std::list<int> new_clients;
-	std::vector<int> clients;
-	uint16_t max_clients;
+	uint16_t port; //!< @brief Port number for the network socket.
+	std::list<int> new_clients; //!< Socket list of new clients.
+	std::vector<int> clients; //!< @brief Socket list of clients.
+	uint16_t max_clients; //!< @brief The maximum number of allowed clients.
+	int sockfd; //!< @brief Network socket used to accept connections.
+
+	/**
+	 * @brief Accept new clients if the total of connected clients is below max_clients.
+	 *
+	 */
+	void _accept();
 
 public:
+	/**
+	 * @brief EthernetServer constructor.
+	 *
+	 * @param port number for the socket addresses.
+	 * @param max_clients The maximum number allowed for connected clients.
+	 */
 	EthernetServer(uint16_t port, uint16_t max_clients = ETHERNETSERVER_MAX_CLIENTS);
+	/**
+	 * @brief Listen for inbound connection request.
+	 *
+	 */
 	virtual void begin();
-	void begin(IPAddress);
-	void beginPacket(IPAddress, uint16_t);
-	int parsePacket();
+	/**
+	 * @brief Listen on the specified ip for inbound connection request.
+	 *
+	 * @param addr IP address to bind to.
+	 */
+	void begin(IPAddress addr);
+	/**
+	 * @brief Verifies if a new client has connected.
+	 *
+	 * @return @c true if a new client has connected, else @c false.
+	 */
 	bool hasClient();
+	/**
+	 * @brief Get the new connected client.
+	 *
+	 * @return client class object if a new client has connected else -1.
+	 */
 	EthernetClient available();
-	virtual size_t write(uint8_t);
-	virtual size_t write(const uint8_t *, size_t);
+	/**
+	 * @brief Write a byte to all clients.
+	 *
+	 * @param b byte to send.
+	 * @return 0 if FAILURE or 1 if SUCCESS.
+	 */
+	virtual size_t write(uint8_t b);
+	/**
+	 * @brief Write at most 'size' bytes to all clients.
+	 *
+	 * @param buffer to read from.
+	 * @param size of the buffer.
+	 * @return 0 if FAILURE else number of bytes sent.
+	 */
+	virtual size_t write(const uint8_t *buffer, size_t size);
+	/**
+	 * @brief Write a null-terminated string to all clients.
+	 *
+	 * @param str String to write.
+	 * @return 0 if FAILURE else number of characters sent.
+	 */
 	size_t write(const char *str);
+	/**
+	 * @brief Write at most 'size' characters to all clients.
+	 *
+	 * @param buffer to read from.
+	 * @param size of the buffer.
+	 * @return 0 if FAILURE else the number of characters sent.
+	 */
 	size_t write(const char *buffer, size_t size);
 };
 

drivers/Linux/Server.h

@@ -20,9 +20,11 @@
 #ifndef server_h
 #define server_h
 
+#if !DOXYGEN
 class Server {
 	public:
 		virtual void begin() =0;
 };
+#endif
 
 #endif