1 files changed, 266 insertions, 0 deletions

diff --git a/tcp.c b/tcp.c
new file mode 100644
index 0000000..d30e7b5
--- /dev/null
+++ b/tcp.c
@@ -0,0 +1,266 @@
+#pragma once
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <signal.h>
+#include <sys/select.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <string.h>
+#include <sys/time.h>
+#define ERR_INET_ADDR "0.9.9.0"
+union ip_conv {
+	unsigned char c[4];
+	struct in_addr in;
+};
+struct in_addr hostname_to_ip (const char * hostname) {
+	struct hostent *he; /* STATIC! */
+	union ip_conv ipconverter;
+	struct in_addr *error_addr = malloc(sizeof(struct in_addr));
+	/* int ret = */ inet_aton(ERR_INET_ADDR, error_addr); /* TODO: chek for err */
+	if ( (he = gethostbyname(hostname)) == NULL ) {
+		herror("gethostbyname");
+		return *error_addr;
+	} else {
+		memcpy(ipconverter.c, he->h_addr, 4); // fuck yes now it works
+		// fprintf(stderr, "debug: %s\n", inet_ntoa(ipconverter.in));
+		return ipconverter.in;
+	}
+}
+int spawn_conn (const char * address, const int port) {
+	int ret;
+	int conn_fd;
+	struct sockaddr_in server_addr = { 0 };
+	server_addr.sin_family = AF_INET;
+	server_addr.sin_port = htons(port);
+	ret = inet_pton(AF_INET, address, &server_addr.sin_addr);
+	if (ret != 1) {
+		if (ret == -1)
+			perror("inet_pton");
+		fprintf(stderr, "%s is not an IPv4, trying to resolve ...\n", address);
+		struct in_addr ret = hostname_to_ip(address);
+		struct in_addr error_addr;
+		inet_aton(ERR_INET_ADDR, &error_addr);
+		if (memcmp(&ret, &error_addr, 4) == 0) {
+			fprintf(stderr, "failed to resolve.\n");
+			return -1;
+		}
+		server_addr.sin_addr = ret;
+		fprintf(stderr, "resolved to  %s.\n", inet_ntoa(server_addr.sin_addr));
+	}
+	conn_fd = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, 0);
+	if(conn_fd == -1) {
+		perror("socket");
+		return -1;
+	}
+	ret = connect(conn_fd, (struct sockaddr*)&server_addr, sizeof(server_addr));
+	if (ret == 1) {
+		perror("connect");
+		return -1;
+	}
+	return conn_fd;
+}
+
+int kill_conn (int conn_fd) {
+	int ret = shutdown(conn_fd, SHUT_RDWR); // preprečimo tako read kot write.:wq
+	if (ret == -1) {
+		perror("shutdown");
+		return -1;
+	}
+	ret = close(conn_fd);
+	if (ret == -1) {
+		perror("close");
+		return -1;
+	}
+	return 0;
+}
+
+int read_until(int conn_fd, FILE * out, unsigned int timeout, const char * ma,
+		unsigned long long int max_bytes) {
+	int ret = 0;
+	unsigned int match = 0;
+	struct timeval start, stop;
+	gettimeofday(&start, NULL);
+	char c[2] = {'\0', '\0'};
+	while (1) {
+		ret = read(conn_fd, c, 1);
+		if (ret == -1) {
+			if (errno == EWOULDBLOCK) {
+			} else {
+				fprintf(stderr, "%s@" __FILE__ ":%d read(): %s%d\n", __func__, __LINE__, strerror(errno), ret);
+				return 1;
+			}
+		} else if (ret == 0) { /* strežnik ni poslal ničesar */
+			fprintf(stderr, "%s@" __FILE__ ":%d read(): server closed connection\n", __func__, __LINE__);
+			return 0;
+		} else {
+			fputc(c[0], out);
+			max_bytes--;
+			if (max_bytes <= 0) {
+				return 0;
+			}
+			if (ma[match] == c[0]) {
+				match++;
+				if (match == strlen(ma)) {
+					return 0;
+				}
+			} else {
+				match = 0;
+			}
+		}
+		gettimeofday(&stop, NULL);
+		if (stop.tv_sec - start.tv_sec > timeout) {
+			fprintf(stderr, "%s@" __FILE__ ":%d E_TIMEOUT %ld-%ld>%u\n", __func__,
+					__LINE__, stop.tv_sec, start.tv_sec, timeout);
+			return 2;
+		}
+	}
+	return 0;
+}
+
+int sync_write(int conn_fd, const char * req, int len, unsigned int timeout) {
+	int ret = write(conn_fd, req, len);
+	struct timeval start, stop;
+	gettimeofday(&start, NULL);
+	if (ret == -1) {
+		if (errno == EBADF) {
+			fprintf(stderr, "tcp.c: sync_write: write EBADF: %s\n", strerror(errno));
+			return -1;
+		}
+		while (errno == EWOULDBLOCK) {
+			ret = write(conn_fd, req, len);
+			if(ret != -1) {
+				return 0;
+			}
+			gettimeofday(&stop, NULL);
+			if (stop.tv_sec - start.tv_sec > timeout) {
+				fprintf(stderr, "tcp.c: sync_write: E_TIMEOUT %ld-%ld>%u\n",
+						start.tv_sec, stop.tv_sec, timeout);
+				return -2;
+			}
+		}
+	}
+	return 0;
+}
+
+
+#if __INCLUDE_LEVEL__ == 0
+	static volatile int sigint = 0;
+	void intHandler(int sig) {
+		signal(sig, SIG_IGN);
+		if (sig == SIGINT)
+			sigint++;
+		if (sigint >= 3) // some people smash CtrlC multiple times to force quit!
+			exit(130);
+		signal(sig, intHandler);
+	}
+	int main (int argc, char ** argv) {
+		if (argc != 1+2) {
+			fprintf(stderr, "usage: %s ip.v4.ad.dr port\n", argv[0]);
+			return 1;
+		}
+		signal(SIGINT, intHandler);
+		#define ADDRESS_ARG argv[1]
+		#define PORT_ARG argv[2]
+		int conn_fd = spawn_conn(ADDRESS_ARG, atoi(PORT_ARG));
+		if (conn_fd < 0) {
+			fprintf(stderr, "error connecting!\n");
+			return 2;
+		} else {
+			fprintf(stderr, "suc. conn with fd %d\n\n", conn_fd);
+		}
+		int buf = 0;
+		#define READ_MAX_SIZE 1024
+		char read_buf[READ_MAX_SIZE];
+		int i = 0;
+		char input;
+		fcntl(STDIN_FILENO, F_SETFL, fcntl(STDIN_FILENO, F_GETFL) | O_NONBLOCK);
+		while (1) {
+			if (sigint > 0) {
+				// fprintf(stderr, "\n" USERSTRING_EXIT_CONFIRM " (y/N)\n");
+				// char gotchar = getchar();
+				// if (gotchar == 'y' || gotchar == 'Y' || gotchar == 'd' ||
+				// 	gotchar == 'D' || gotchar == 'j' || gotchar == 'J') {
+				// 	kill_conn(conn_fd);
+				// 	return 0;
+				// }
+				if (kill_conn(conn_fd) == 0) {
+					fprintf(stderr, "\nconnection killed successfully, exiting ...\n");
+				} else {
+					fprintf(stderr, "\nconnection killing FAILED, exiting ...\n");
+				}
+				return 0;
+			}
+			buf = read(conn_fd, read_buf, READ_MAX_SIZE);
+			if (buf == -1 && errno != EWOULDBLOCK) {
+				fprintf(stderr, "\nerror reading from socket.\n");
+				if (kill_conn(conn_fd) != 0) {
+					fprintf(stderr, "\nerror killing socket\n");
+					return 3;
+				}
+				return 4;
+			}
+			if (buf == 0) {
+				fprintf(stderr, "\nserver closed socket\n");
+				if (kill_conn(conn_fd) != 0) {
+					fprintf(stderr, "\nerror killing socket\n");
+					return 5;
+				}
+				return 6;
+			}
+			if (errno == EWOULDBLOCK && buf == -1) {
+				// no data is on socket; sockets are non blocking.
+			} else {
+				buf = write(STDOUT_FILENO, read_buf, buf);
+				if(buf == -1) {
+					fprintf(stderr, "\nerror writing to stdout\n");
+					return 7;
+				}
+			}
+			buf = read(STDIN_FILENO, read_buf, READ_MAX_SIZE);
+			if (buf == -1 && errno != EWOULDBLOCK) {
+				fprintf(stderr, "\nerror reading from stdin\n");
+				return 8;
+			}
+			if (buf == 0) {
+				// fprintf(stderr, "\neof on stdin\n"); // that's okay
+				// return 9;
+			}
+			if (errno == EWOULDBLOCK && buf == -1) {
+				// no data in stdin
+			} else {
+				i = write(conn_fd, read_buf, buf);
+				if (i == -1) {
+					if(errno != EWOULDBLOCK) {
+						fprintf(stderr, "\nerror writing to socket\n");
+						if(kill_conn(conn_fd) != 0) {
+							fprintf(stderr, "\nerror killing connection\n");
+							return 10;
+						}
+						return 12;
+					} else {
+						while (i == -1) {
+							if (errno == EWOULDBLOCK) {
+								fprintf(stderr, "\nwrite to socket blocked, trying again\n");
+								i = write (conn_fd, read_buf, buf);
+							} else {
+								fprintf(stderr, "\nerror writing to socket\n");
+								if (kill_conn(conn_fd) != 0) {
+									fprintf(stderr, "\nerror killing connection\n");
+									return 13;
+								}
+								return 14;
+							}
+						}
+					}
+				}
+			}
+			buf = 0;
+		}
+	}
+#endif