completed set 4, task 31

1 files changed, 88 insertions, 0 deletions

diff --git a/set4/task31.c b/set4/task31.c
new file mode 100644
index 0000000..1c613dd
--- /dev/null
+++ b/set4/task31.c
@@ -0,0 +1,88 @@
+#include "../lib/lib.h"
+#include "../lib/lib2.h"
+#include "../lib/lib3.h"
+#include "../lib/lib4.h"
+#include <time.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <arpa/inet.h>
+#include <math.h>
+
+int get_max(long *numbers, int length)
+{
+	long max;
+	int ret;
+	int i;
+
+	for(i=0;i<length;i++) {
+		if(numbers[i] > max) {
+			max = numbers[i];
+			ret = i;
+		}
+	}
+
+	return ret;
+}
+
+int main(int argc, char **argv)
+{
+	int socket_fd;
+	struct sockaddr_in serv_addr;
+	char *server_addr = "127.0.0.1";
+	char *http_request_template = "GET /?file=neu&signature=%s HTTP/1.1\r\n\r\n";
+	// sha1 is 20 bytes, in hex 40
+	char *signature = malloc(40+1);
+	char *http_request = malloc(strlen(http_request_template) + 20);
+	memset(signature, '0', 40+1);
+	signature[40] = '\0';
+	struct timespec time;
+	int i, j;
+	char c;
+	long response_times[16];
+	char *response = malloc(2000);
+
+
+	for(i=0;i<40;i++) {
+		for(j=0;j<16;j++) {
+			// connect to localhost:80
+			socket_fd = socket(AF_INET, SOCK_STREAM, 0);
+
+			if (socket_fd == -1)
+				perror("Can not create socket");
+
+			serv_addr.sin_family = AF_INET;
+			serv_addr.sin_port = htons(8080);
+			serv_addr.sin_addr.s_addr = inet_addr(server_addr);
+
+			if(connect(socket_fd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0) {
+				perror("Can not connect");
+			}
+			// send http request
+			// brute force every byte of the signature
+			c = j > 9 ? 'a' + (j-10) : '0' + j;
+			signature[i] = c;
+			sprintf(http_request, http_request_template, signature);
+			//printf("request: %s\n", http_request);
+			clock_gettime(CLOCK_MONOTONIC, &time);
+			long start_time = (time.tv_sec * 1000000 + time.tv_nsec/1000);
+
+			write(socket_fd, http_request, strlen(http_request));
+
+
+			read(socket_fd, response, 2000);
+
+			clock_gettime(CLOCK_REALTIME, &time);
+
+			long stop_time = time.tv_sec * 1000000 + time.tv_nsec/1000;
+
+			memset(response, 0, 2000);
+			response_times[j] = (stop_time) - (start_time);
+
+			close(socket_fd);
+		}
+		// ok now choose the right one (the one where the latency is max
+		int index = get_max(response_times, 16);
+		signature[i] = index > 9 ? 'a' + (index-10) : '0' + index;
+		printf("signature so far: %s\n", signature);
+	}
+}