Add new code

Signed-off-by: Carlos Maiolino <[email protected]>

4 files changed, 296 insertions, 0 deletions

diff --git a/C/netCode/.gitignore b/C/netCode/.gitignore
new file mode 100644
index 0000000..f2ad853
--- /dev/null
+++ b/C/netCode/.gitignore
@@ -0,0 +1,2 @@
+client
+server
diff --git a/C/netCode/client.c b/C/netCode/client.c
new file mode 100644
index 0000000..dafd1e8
--- /dev/null
+++ b/C/netCode/client.c
@@ -0,0 +1,66 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+
+#include "types.h"
+
+void handle_client(int fd)
+{
+	char buf[4096] = {0};
+	int *data;
+	proto_hdr_t *hdr = (proto_hdr_t*)buf;
+
+
+	read(fd, buf, sizeof(proto_hdr_t) + sizeof(int));
+
+	hdr->type = ntohl(hdr->type);
+	hdr->len = ntohs(hdr->len);
+
+	data = (int *)&hdr[1];
+	*data = ntohl(*data);
+
+	if (hdr->type != PROTO_HELLO)
+		printf("Protocol mismatch\n");
+
+	if (*data != 1)
+		printf("Protocol version mismatch\n");
+
+	printf("Client connected - proto: %d ver: %d payload: %d\n",
+	       hdr->type, hdr->len, *data);
+}
+
+int main(int argc, char *argv[])
+{
+	int err;
+	struct sockaddr_in serverInfo = {0};
+	int fd = socket(AF_INET, SOCK_STREAM, 0);
+
+	if (argc != 2) {
+		printf("Usage: ./client <ip>\n");
+		exit(1);
+	}
+
+	serverInfo.sin_family = AF_INET;
+	serverInfo.sin_addr.s_addr = inet_addr(argv[1]);;
+	serverInfo.sin_port = htons(SERVER_PORT);
+
+	if (fd < 0) {
+		perror("socket");
+		exit(1);
+	}
+
+	err = connect(fd, (struct sockaddr*)&serverInfo, sizeof(serverInfo));
+	if (err < 0) {
+		perror("connect");
+		close(fd);
+		exit(1);
+	}
+
+	handle_client(fd);
+	close(fd);
+	return 0;
+}
diff --git a/C/netCode/server.c b/C/netCode/server.c
new file mode 100644
index 0000000..0b951eb
--- /dev/null
+++ b/C/netCode/server.c
@@ -0,0 +1,202 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <poll.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include "types.h"
+
+clientstate_t clientStates[MAX_CLIENTS];
+
+void init_clients(void) {
+	int i;
+
+	for (i = 0; i < MAX_CLIENTS; i++) {
+		/* -1 means client slot is free */
+		clientStates[i].fd = -1;
+		clientStates[i].state = STATE_NEW;
+		memset(&clientStates[i].buffer, 0, BUF_SIZE);
+	}
+}
+
+int find_free_client(void) {
+	int i = 0;
+
+	for (i = 0; i < MAX_CLIENTS; i++)
+		if (clientStates[i].fd == -1)
+			return i;
+
+	return -1;
+}
+
+int find_slot_by_fd(int fd)
+{
+	int i;
+	for (i = 0; i < MAX_CLIENTS; i++) {
+		if (clientStates[i].fd == fd)
+			return i;
+	}
+	return -1;
+}
+
+void handle_client(int fd)
+{
+	char buf[4096] = {0};
+	proto_hdr_t *hdr = (proto_hdr_t*)buf;
+	int *data;
+	int reallen;
+
+	hdr->type = htonl(PROTO_HELLO);
+	reallen = sizeof(int);
+	hdr->len = htons(reallen);
+
+	data = (int *)&hdr[1];
+	*data = htonl(1);
+
+	printf("hdr_ptr: %p data_ptr: %p\n", hdr, data);
+	write(fd, hdr, sizeof(proto_hdr_t) + reallen);
+
+}
+
+
+int main(void)
+{
+	int err;
+	int listen_fd, conn_fd, nfds, freeSlot;
+	struct sockaddr_in serverInfo = {0};
+	struct sockaddr_in clientInfo = {0};
+	socklen_t csize;
+	int opt = 1;
+
+	struct pollfd fds[MAX_CLIENTS + 1];
+
+	memset(fds, 9, sizeof(fds));
+	serverInfo.sin_family = AF_INET;
+	serverInfo.sin_addr.s_addr = 0; /* bind to all IPs */
+	serverInfo.sin_port = htons(SERVER_PORT);
+
+	init_clients();
+
+	listen_fd = socket(AF_INET, SOCK_STREAM, 0);
+	if (listen_fd < 0) {
+		perror("socket");
+		exit(1);
+	}
+
+	err = bind(listen_fd,
+		   (struct sockaddr *)&serverInfo,
+		   sizeof(serverInfo));
+
+	if (err < 0) {
+		perror("bind");
+		close(listen_fd);
+		exit(1);
+	}
+
+	err = listen(listen_fd, 0);
+	if (err < 0) {
+		perror("listen");
+		close(listen_fd);
+		exit(1);
+	}
+
+	if (setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) == -1) {
+		perror("setsockopt");
+		close(listen_fd);
+		exit(1);
+	}
+
+	printf("Server listening to port: %d\n", SERVER_PORT);
+
+	csize = sizeof(clientInfo);
+
+	fds[0].fd = listen_fd;
+	fds[0].events = POLLIN;
+	nfds = 1;
+
+	while (1) {
+		int i, j;
+		int nevents;
+
+		/* fds is initialized with MAX_CLIENTS + 1 */
+		for (i = 0, j = 1; i < MAX_CLIENTS; i++, j++) {
+			if (clientStates[i].fd != -1) {
+				/* Add open fd to the poll */
+				fds[j].fd = clientStates[i].fd;
+				fds[j].events = POLLIN;
+				printf("FD %d added to poll\n", clientStates[i].fd);
+			}
+		}
+
+		nevents = poll(fds, nfds, -1);
+
+		if (nevents == -1) {
+			perror("poll");
+			exit(1);
+		}
+
+		/* if listen_fd is ready, accept it */
+		if (fds[0].revents & POLLIN) {
+			conn_fd = accept(listen_fd,
+					 (struct sockaddr*)&clientInfo,
+					 &csize);
+
+			if (conn_fd < 0) {
+				perror("accept");
+				continue;
+			}
+
+			printf("New connection from: %s:%d\n",
+			       inet_ntoa(clientInfo.sin_addr),
+			       ntohs(clientInfo.sin_port));
+
+			freeSlot = find_free_client();
+			if (freeSlot < 0) {
+				printf("Server full - closing connection\n");
+				close(conn_fd);
+			} else {
+				clientStates[freeSlot].fd = conn_fd;
+				clientStates[freeSlot].state = STATE_CONNECTED;
+				nfds++;
+				printf("Adding fd %d to slot %d\n",
+				       conn_fd, freeSlot);
+			}
+			nevents--;
+		}
+
+		printf("NFDS: %d\n", nfds);
+		for (i = 1; i <= nfds && nevents > 0; i++) {
+			int fd, slot;
+			ssize_t bytes_read;
+
+			if (fds[i].revents & POLLIN) {
+				nevents--;
+
+				fd = fds[i].fd;
+				slot = find_slot_by_fd(fd);
+				bytes_read = read(fd,
+						  &clientStates[slot].buffer,
+						  sizeof(clientStates[slot].buffer));
+				if (bytes_read <= 0) {
+					close(fd);
+					printf("Connection error\n");
+					if (slot == -1) {
+						printf("Trying to close an invalid fd\n");
+					} else {
+						clientStates[slot].fd = -1;
+						clientStates[slot].state = STATE_DISCONNECTED;
+						printf("Client disconnected or error\n");
+						nfds--;
+					}
+				} else {
+					printf("Data received: %s\n", clientStates[slot].buffer);
+				}
+			}
+
+		}
+	}
+	return 0;
+}
diff --git a/C/netCode/types.h b/C/netCode/types.h
new file mode 100644
index 0000000..e70974e
--- /dev/null
+++ b/C/netCode/types.h
@@ -0,0 +1,26 @@
+#define SERVER_PORT 5555
+#define MAX_CLIENTS 5
+#define BUF_SIZE 4096
+
+typedef enum {
+	PROTO_HELLO,
+} proto_type_e;
+
+/* Type-Length-Value */
+typedef struct {
+	proto_type_e type;
+	unsigned short len;
+} proto_hdr_t;
+
+typedef enum {
+	STATE_NEW,
+	STATE_CONNECTED,
+	STATE_DISCONNECTED,
+} state_e;
+
+typedef struct {
+	int fd;
+	state_e state;
+	char buffer[BUF_SIZE];
+} clientstate_t;
+