rename hashmap

include/hashmap.h

@@ -1,6 +1,7 @@
 #ifndef __HASHMAP_C__
 #define __HASHMAP_C__
 
+#include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
@@ -8,11 +9,12 @@
 /* Each process on Linux can have a maximum of 1024 open file descriptors */
 #define HASHMAP_MAX_CLIENTS 1024
 
-struct hashmap {
-	int sockfd;
-	struct sockaddr_storage sas;
-	struct hashmap *next;
-};
+typedef struct bucket {
+	int sockfd;		     /**< Client socket descriptor */
+	struct sockaddr_storage sas; /**< Associated socket address */
+	struct bucket *next;	     /**< Next node in case of collision */
+	struct bucket *prev;	     /**< Previous node in case of collision */
+} bucket_t;
 
 /**
  * @brief Calculates the hash code of a given file descriptor
@@ -25,35 +27,60 @@ int hash(int sockfd);
 /**
  * @brief Initializes the hash map
  *
- * @param map[out] The hash map uninitialized
+ * @param bucket[out] The hash map uninitialized
  */
-void hm_init(struct hashmap *map);
+void hm_init(bucket_t *bucket);
 
 /**
  * @brief Inserts a key in the hash map
  *
- * @param map[out] The hash map
+ * @param bucket[out] The hash map
  * @param sockfd[in] The file descriptor (value)
  * @param sas[in] The sockaddr (value)
  */
-void hm_push(struct hashmap *map, int sockfd, struct sockaddr_storage *sas);
+void hm_push(bucket_t *bucket, int sockfd, struct sockaddr_storage *sas);
+
+/**
+ * @brief Removes a key from the hash map
+ *
+ * @param bucket[out] The hash map
+ * @param sockfd[in] The key
+ */
+void hm_remove(bucket_t *bucket, int sockfd);
 
 /**
  * @brief Searches for a key in the hash map
  *
- * @param map[in] The hash map
+ * @param bucket[in] The hash map
  * @param sockfd[in] The file descriptor (key)
  * @return struct hashmap* Returns NULL or the key pointer
  */
-struct hashmap *hm_lookup(struct hashmap *map, int sockfd);
+bucket_t *hm_lookup(bucket_t *bucket, int sockfd);
 
 /**
  * @brief Cleans the hash map
  *
- * @param map[out] The hash map
+ * @param bucket[out] The hash map
  */
-void hm_free(struct hashmap *map);
+void hm_free(bucket_t *bucket);
 
-void hm_insert(struct hashmap *map, int sockfd, struct sockaddr_storage *sas);
+/**
+ * @brief Checks if a file descriptor is in the bucket array (not linked list)
+ *
+ * @param bucket[in]
+ * @param sockfd[in]
+ * @return true If the file descriptor is in the bucket array
+ * @return false If the file descriptor is not in the bucket array (check with hm_lookup())
+ */
+bool hm_is_in_bucket_array(bucket_t *bucket, int sockfd);
+
+/**
+ * @brief This function will add a key even if it exists (use hm_push() instead)
+ *
+ * @param bucket
+ * @param sockfd
+ * @param sas
+ */
+void hm_insert(bucket_t *bucket, int sockfd, struct sockaddr_storage *sas);
 
 #endif

include/server.h

@@ -14,6 +14,8 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#include "hashmap.h"
+
 /* On which port the server will run */
 #define PORT 3030
 
@@ -86,4 +88,11 @@ void setnonblocking(int sockfd);
  */
 int handle_new_client(int sockfd, struct sockaddr_storage *their_sa, socklen_t *theirsa_size);
 
+/**
+ * @brief Closes all the file descriptors opened
+ *
+ * @param map[in] The hash map
+ */
+void close_fds(bucket_t *bucket);
+
 #endif

src/hashmap.c

@@ -2,64 +2,84 @@
 
 int hash(int sockfd) { return sockfd % HASHMAP_MAX_CLIENTS; }
 
-void hm_init(struct hashmap *map) {
+void hm_init(bucket_t *bucket) {
 	/* Initialize everything to 0 for the struct, then -1 for fd and next to NULL */
-	memset(map, 0, sizeof(struct hashmap) * HASHMAP_MAX_CLIENTS);
+	memset(bucket, 0, sizeof(bucket_t) * HASHMAP_MAX_CLIENTS);
 
 	for (size_t i = 0; i < HASHMAP_MAX_CLIENTS; ++i) {
-		map[i].sockfd = -1;
-		map[i].next = NULL;
+		bucket[i].sockfd = -1;
+		bucket[i].next = NULL;
+		bucket[i].prev = NULL;
 	}
 }
 
-/* This function will add a key even if it exists (use hm_push() instead) */
-void hm_insert(struct hashmap *map, int sockfd, struct sockaddr_storage *sas) {
+void hm_insert(bucket_t *bucket, int sockfd, struct sockaddr_storage *sas) {
 	int index = hash(sockfd);
 
-	if (map[index].sockfd == -1) {
+	if (bucket[index].sockfd == -1) {
 		/* Current slot is empty */
-		map[index].sockfd = sockfd;
-		map[index].sas = *sas;
-		map[index].next = NULL;
+		bucket[index].sockfd = sockfd;
+		bucket[index].sas = *sas;
 	} else {
 		/* Append the new key to the head (not the first element because it belongs to the array) of the linked
 		 * list */
-		struct hashmap *p = &map[index];
-		struct hashmap *new = malloc(sizeof(struct hashmap));
+		bucket_t *p = &bucket[index];
+		bucket_t *new = malloc(sizeof(bucket_t));
 		new->sockfd = sockfd;
 		new->sas = *sas;
 		new->next = p->next;
+		new->prev = p;
 		p->next = new;
 	}
 }
 
-struct hashmap *hm_lookup(struct hashmap *map, int sockfd) {
+bucket_t *hm_lookup(bucket_t *bucket, int sockfd) {
 	int index = hash(sockfd);
 
-	if (map[index].sockfd != sockfd) {
-		struct hashmap *p;
-		for (p = map[index].next; p != NULL && p->sockfd != sockfd; p = p->next);
+	if (bucket[index].sockfd != sockfd) {
+		bucket_t *p;
+		for (p = bucket[index].next; p != NULL && p->sockfd != sockfd; p = p->next);
 		return p;
 	} else {
-		return &map[index];
+		return &bucket[index];
 	}
 
 	return NULL;
 }
 
-void hm_push(struct hashmap *map, int sockfd, struct sockaddr_storage *sas) {
-	if (hm_lookup(map, sockfd) == NULL) {
-		hm_insert(map, sockfd, sas);
+void hm_push(bucket_t *bucket, int sockfd, struct sockaddr_storage *sas) {
+	if (hm_lookup(bucket, sockfd) == NULL) {
+		hm_insert(bucket, sockfd, sas);
 	}
 }
 
-void hm_free(struct hashmap *map) {
-	struct hashmap *p, *next;
+void hm_remove(bucket_t *bucket, int sockfd) {
+	if (hm_is_in_bucket_array(bucket, sockfd)) {
+		/* Instead of doing this I could copy the memory of the next node into the head */
+		int index = hash(sockfd);
+		bucket[index].sockfd = -1;
+
+		return;
+	}
+
+	/* Key not in the bucket array, let's search in the linked list */
+	bucket_t *p = hm_lookup(bucket, sockfd);
+	if (p == NULL) return;
+	p->prev->next = p->next;
+	if (p->next != NULL) {
+		/* If there's a next node update the previous node */
+		p->next->prev = p->prev;
+	}
+	free(p);
+}
+
+void hm_free(bucket_t *bucket) {
+	bucket_t *p, *next;
 
 	for (size_t i = 0; i < HASHMAP_MAX_CLIENTS; ++i) {
-		if (map[i].next != NULL) {
+		if (bucket[i].next != NULL) {
 			/* Free the malloc */
-			p = map[i].next;
+			p = bucket[i].next;
 			next = p->next;
 			do {
 				free(p);
@@ -69,3 +89,10 @@ void hm_free(struct hashmap *map) {
 		}
 	}
 }
+
+bool hm_is_in_bucket_array(bucket_t *bucket, int sockfd) {
+	int index = hash(sockfd);
+	if (bucket[index].sockfd == sockfd) return true;
+
+	return false;
+}

src/server.c

@@ -41,10 +41,13 @@ int start_server(const char *hostname, const char *service) {
 
 void setup_hints(struct addrinfo *hints, size_t len, const char *hostname) {
 	memset(hints, 0, len);
-	hints->ai_family = AF_UNSPEC;	   // IPv4 or IPv6
-	hints->ai_socktype = SOCK_STREAM;  // TCP
+	/* IPv4 or IPv6 */
+	hints->ai_family = AF_UNSPEC;
+	/* TCP */
+	hints->ai_socktype = SOCK_STREAM;
 	if (hostname == NULL) {
-		hints->ai_flags = AI_PASSIVE;  // fill in IP for me
+		/* Fill in IP for me */
+		hints->ai_flags = AI_PASSIVE;
 	}
 }
 
@@ -52,7 +55,7 @@ void handle_clients(int sockfd) {
 	struct sockaddr_storage their_sa;
 	socklen_t theirsa_size = sizeof their_sa;
 
-	struct hashmap clients[HASHMAP_MAX_CLIENTS];
+	bucket_t clients[HASHMAP_MAX_CLIENTS];
 	hm_init(clients);
 
 	int epfd = epoll_create1(0);
@@ -73,7 +76,7 @@ void handle_clients(int sockfd) {
 
 		for (int i = 0; i < nfds; ++i) {
 			if (revents[i].data.fd == sockfd) {
-				// new client
+				/* New client */
 				client_fd = handle_new_client(sockfd, &their_sa, &theirsa_size);
 
 				setnonblocking(client_fd);
@@ -83,14 +86,14 @@ void handle_clients(int sockfd) {
 				int bytes_sent = send(client_fd, msg, msg_len, 0);
 				fprintf(stdout, "[server] Sent %d bytes\n", bytes_sent);
 			} else {
-				// incoming data
+				/* Incoming data */
 				client_fd = revents[i].data.fd;
 				int bytes_read = recv(client_fd, data, sizeof data, 0);
 
 				if (bytes_read == 0) {
-					// client disconnected
+					/* Client disconnected */
 					char ip[INET_ADDRSTRLEN];
-					struct hashmap *client = hm_lookup(clients, client_fd);
+					bucket_t *client = hm_lookup(clients, client_fd);
 					get_client_ip(&client->sas, ip);
 
 					fprintf(stdout, BLUE "[server] Client (%s) disconnected\n" RESET, ip);
@@ -112,13 +115,7 @@ void handle_clients(int sockfd) {
 
 	free(revents);
 	close(epfd);
-
-	/* Close all the file descriptors */
-	for (size_t i = 0; i < HASHMAP_MAX_CLIENTS; ++i) {
-		close(clients[i].sockfd);
-		/* TODO: close collisions */
-	}
-
+	close_fds(clients);
 	hm_free(clients);
 }
 
@@ -127,6 +124,7 @@ void epoll_ctl_add(int epfd, int sockfd, uint32_t events) {
 	event.events = events;
 	event.data.fd = sockfd;
 	int status = epoll_ctl(epfd, EPOLL_CTL_ADD, sockfd, &event);
+
 	if (status != 0) {
 		fprintf(stderr, RED BOLD "[server] epoll_ctl_add(): %s\n" RESET, strerror(errno));
 		exit(EXIT_FAILURE);
@@ -135,6 +133,7 @@ void epoll_ctl_add(int epfd, int sockfd, uint32_t events) {
 
 void epoll_ctl_del(int epfd, int sockfd) {
 	int status = epoll_ctl(epfd, EPOLL_CTL_DEL, sockfd, NULL);
+
 	if (status != 0) {
 		fprintf(stdout, RED BOLD "[server] epoll_ctl_del(): %s\n" RESET, strerror(errno));
 		exit(EXIT_FAILURE);
@@ -143,6 +142,7 @@ void epoll_ctl_del(int epfd, int sockfd) {
 
 void setnonblocking(int sockfd) {
 	int status = fcntl(sockfd, F_SETFL, O_NONBLOCK);
+
 	if (status == -1) {
 		fprintf(stderr, RED BOLD "[server] fcntl(): %s\n" RESET, gai_strerror(status));
 		exit(EXIT_FAILURE);
@@ -161,3 +161,21 @@ int handle_new_client(int sockfd, struct sockaddr_storage *their_sa, socklen_t *
 
 	return client_fd;
 }
+
+void close_fds(bucket_t *bucket) {
+	bucket_t *p, *next;
+
+	for (size_t i = 0; i < HASHMAP_MAX_CLIENTS; ++i) {
+		close(bucket[i].sockfd);
+		if (bucket[i].next != NULL) {
+			/* Close the fds */
+			p = bucket[i].next;
+			next = p->next;
+			do {
+				close(p->sockfd);
+				p = next;
+				next = p != NULL ? p->next : NULL;
+			} while (p != NULL);
+		}
+	}
+}