Duzy commit ze smieciami

16 files changed, 761 insertions, 0 deletions

diff --git a/semestr-4/sieci/pracownia3/4pkt/config.h b/semestr-4/sieci/pracownia3/4pkt/config.h
new file mode 100644
index 0000000..42ccd89
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/4pkt/config.h
@@ -0,0 +1,7 @@
+#ifndef CONFIG_H
+#define CONFIG_H
+
+#define DATAGRAM_LEN 1000
+#define HEADER_LEN 40
+
+#endif
diff --git a/semestr-4/sieci/pracownia3/4pkt/transport.c b/semestr-4/sieci/pracownia3/4pkt/transport.c
new file mode 100644
index 0000000..806eb4e
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/4pkt/transport.c
@@ -0,0 +1,152 @@
+#include <netinet/ip.h>
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <time.h>
+#include <poll.h>
+#include <stdbool.h>
+#include "config.h"
+
+#define NS_TO_MS(X) ((long)(X) / (long)1000000)
+#define S_TO_MS(X) ((long)(X) * (long)1000)
+
+int get_socket() {
+  int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
+  if (sockfd < 0) {
+    fprintf(stderr, "socket error: %s", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  return sockfd;
+}
+
+size_t send_datagram(int sockfd, struct sockaddr_in server_address, char *buffer, size_t buffer_len) {
+  return sendto(sockfd, buffer, buffer_len, 0, (struct sockaddr*) &server_address, sizeof(server_address));
+}
+
+void send_data_request(int sockfd, struct sockaddr_in server_address, size_t pos, size_t bytes) {
+  char buffer[40];
+  sprintf(buffer, "GET %ld %ld\n", pos, bytes);
+  size_t buffer_len = strlen(buffer);
+  if (send_datagram(sockfd, server_address, buffer, buffer_len) != buffer_len) {
+    fprintf(stderr, "sendto error: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+}
+
+long get_time_interval(struct timespec start, struct timespec finish) {
+  return S_TO_MS(finish.tv_sec - start.tv_sec) + NS_TO_MS(finish.tv_nsec - start.tv_nsec);
+}
+
+int poll_socket_modify_timeout(int sockfd, int *timeout) {
+  if (*timeout < 0) {
+    *timeout = 0;
+    return 0;
+  }
+
+  struct pollfd fds;
+  struct timespec start;
+  struct timespec finish;
+  
+  fds.fd = sockfd;
+  fds.events = POLLIN;
+  fds.revents = 0;
+  
+  clock_gettime(CLOCK_REALTIME, &start);
+  int result = poll(&fds, 1, *timeout);
+  clock_gettime(CLOCK_REALTIME, &finish);
+  
+  if (result == -1) {
+    fprintf(stderr, "poll error: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  if (result == 0) {
+    *timeout = 0;
+    return 0;
+  }
+
+  *timeout -= get_time_interval(start, finish);
+  return result;
+}   
+
+size_t recv_message(int sockfd, char *buffer, struct sockaddr_in *sender) {
+  socklen_t sender_len = sizeof(*sender);
+  bzero(buffer, HEADER_LEN + DATAGRAM_LEN);
+  bzero(sender, sizeof(*sender));
+  size_t datagram_len = recvfrom(sockfd, buffer, IP_MAXPACKET, 0,
+    (struct sockaddr*)sender, &sender_len);
+
+  if (datagram_len < 0) {
+    fprintf(stderr, "recvfrom error: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  
+  return datagram_len;
+}
+
+inline size_t min(size_t x, size_t y) { return (x<y ? x : y); }
+
+void receive_file(int sockfd, struct sockaddr_in server_address, const char *file_name, size_t file_len) {
+  FILE *fd = fopen(file_name, "w");
+  if (!fd) {
+    fprintf(stderr, "fopen error: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  size_t bytes_writen = 0;
+  
+  size_t recv_pos, recv_len;
+  struct sockaddr_in sender;
+  char buffer[DATAGRAM_LEN + HEADER_LEN];
+  int prev_len = 0;
+
+  while (file_len) {
+    send_data_request(sockfd, server_address, bytes_writen, min(file_len, DATAGRAM_LEN));
+    int timeout = 10;
+    while (poll_socket_modify_timeout(sockfd, &timeout)) {
+      size_t received_bytes = recv_message(sockfd, buffer, &sender);
+      if (sender.sin_addr.s_addr != server_address.sin_addr.s_addr || sender.sin_port != server_address.sin_port) continue;
+      sscanf(buffer, "DATA %ld %ld\n", &recv_pos, &recv_len);
+      if (recv_pos != bytes_writen) continue;
+      fwrite(buffer + received_bytes - recv_len, sizeof(char), recv_len, fd);  
+      file_len -= recv_len;
+      bytes_writen += recv_len;
+      break;    
+    }
+    if (prev_len != bytes_writen) {
+      prev_len = bytes_writen;
+      printf("%.3f%%\n", 100.0 * (float)(bytes_writen) / (float)(file_len+bytes_writen));
+    }
+  }
+
+  fclose(fd);
+}
+
+int main(int argc, char *argv[]) {
+  if (argc != 5) {
+    printf("Usage:\n\t%s [server ip] [server port] [output file name] [file size]\n", argv[0]);
+    return -1;
+  }
+
+  int sockfd = get_socket();
+  struct sockaddr_in server_address;
+  bzero(&server_address, sizeof(server_address));
+  server_address.sin_family = AF_INET;
+  if (!inet_pton(AF_INET, argv[1], &server_address.sin_addr)) {
+    fprintf(stderr, "Invalid ip address: %s\n", argv[1]);
+    return -1;
+  }
+  server_address.sin_port = htons(atoi(argv[2]));
+  if (server_address.sin_port == 0) {
+    fprintf(stderr, "Invalid port: %s\n", argv[2]);
+    return -1;
+  }
+
+  size_t file_len = atoi(argv[4]);
+  if (file_len == 0) {
+    printf("File len is 0, nothing to do here.\n");
+    return 0;
+  }
+
+  receive_file(sockfd, server_address, argv[3], file_len);
+}
\ No newline at end of file
diff --git a/semestr-4/sieci/pracownia3/config.h b/semestr-4/sieci/pracownia3/config.h
new file mode 100644
index 0000000..3b81646
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/config.h
@@ -0,0 +1,10 @@
+#ifndef CONFIG_H
+#define CONFIG_H
+
+#define DATAGRAM_LEN 1000
+#define HEADER_LEN 40
+
+#define WINDOW_SIZE 3000
+#define TIMEOUT 100
+
+#endif
diff --git a/semestr-4/sieci/pracownia3/franciszek_malinka.tar.xz b/semestr-4/sieci/pracownia3/franciszek_malinka.tar.xz
new file mode 100644
index 0000000..6db8320
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/franciszek_malinka.tar.xz
diff --git a/semestr-4/sieci/pracownia3/franciszek_malinka/config.h b/semestr-4/sieci/pracownia3/franciszek_malinka/config.h
new file mode 100644
index 0000000..3b81646
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/franciszek_malinka/config.h
@@ -0,0 +1,10 @@
+#ifndef CONFIG_H
+#define CONFIG_H
+
+#define DATAGRAM_LEN 1000
+#define HEADER_LEN 40
+
+#define WINDOW_SIZE 3000
+#define TIMEOUT 100
+
+#endif
diff --git a/semestr-4/sieci/pracownia3/franciszek_malinka/transport.c b/semestr-4/sieci/pracownia3/franciszek_malinka/transport.c
new file mode 100644
index 0000000..9226d69
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/franciszek_malinka/transport.c
@@ -0,0 +1,149 @@
+/* Projekt: Transport
+ * Autor: Franciszek Malinka 316093
+ */
+
+#include <netinet/ip.h>
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <stdbool.h>
+#include "config.h"
+#include "window.h"
+#include "utils.h"
+
+size_t send_datagram(int sockfd, struct sockaddr_in server_address, char *buffer, size_t buffer_len) {
+  return sendto(sockfd, buffer, buffer_len, 0, (struct sockaddr*) &server_address, sizeof(server_address));
+}
+
+void send_data_request(int sockfd, struct sockaddr_in server_address, size_t pos, size_t bytes) {
+  char buffer[40];
+  sprintf(buffer, "GET %ld %ld\n", pos, bytes);
+  size_t buffer_len = strlen(buffer);
+  if (send_datagram(sockfd, server_address, buffer, buffer_len) != buffer_len) {
+    fprintf(stderr, "sendto error: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+}
+
+size_t recv_message(int sockfd, char *buffer, struct sockaddr_in *sender) {
+  socklen_t sender_len = sizeof(*sender);
+  bzero(buffer, HEADER_LEN + DATAGRAM_LEN);
+  bzero(sender, sizeof(*sender));
+  size_t datagram_len = recvfrom(sockfd, buffer, IP_MAXPACKET, 0,
+    (struct sockaddr*)sender, &sender_len);
+
+  if (datagram_len < 0) {
+    fprintf(stderr, "recvfrom error: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  
+  return datagram_len;
+}
+
+void request_data(int sockfd, struct sockaddr_in server_address, window_t *w, size_t bytes_writen, size_t remaining_bytes) {
+  int pos = w->first_pos;
+  for (int i = 0; i < w->size && i*DATAGRAM_LEN < remaining_bytes; i++) {
+    if (w->uptodate[pos] == false) {
+      size_t bytes_to_request = min(DATAGRAM_LEN, remaining_bytes - i*DATAGRAM_LEN);
+      send_data_request(sockfd, server_address, bytes_writen + i*DATAGRAM_LEN, bytes_to_request);
+    }
+    pos = (pos + 1) % w->size;
+  }
+}
+
+void update_file(FILE *fd, window_t *w, size_t *bytes_writen, size_t *remaining_bytes) {
+  while (w->uptodate[w->first_pos] && *remaining_bytes > 0) {
+    // printf("Writing %ld\n", *bytes_writen);
+    size_t bytes_to_write = min(DATAGRAM_LEN, *remaining_bytes);
+    fwrite(w->ar[w->first_pos], sizeof(char), bytes_to_write, fd);  
+    *bytes_writen += bytes_to_write;
+    *remaining_bytes -= bytes_to_write;
+    shift(w);
+  } 
+}
+
+size_t recv_datagram(int sockfd, char *buffer, struct sockaddr_in server_address) {
+  struct sockaddr_in sender;
+  
+  size_t received_bytes = recv_message(sockfd, buffer, &sender);
+  if (sender.sin_addr.s_addr != server_address.sin_addr.s_addr || sender.sin_port != server_address.sin_port) {
+    printf("Smieci!\n");
+    return 0;
+  }
+  return received_bytes;  
+}
+
+
+void receive_file(int sockfd, struct sockaddr_in server_address, const char *file_name, size_t remaining_bytes) {
+  FILE *fd = fopen(file_name, "w");
+  if (!fd) {
+    fprintf(stderr, "fopen error: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  size_t bytes_writen = 0;
+  
+  size_t recv_pos, recv_len;
+  char buffer[DATAGRAM_LEN + HEADER_LEN];
+  int prev_len = 0;
+  window_t w;
+  init_window(&w, WINDOW_SIZE, DATAGRAM_LEN);
+  
+  while (remaining_bytes) {
+    request_data(sockfd, server_address, &w, bytes_writen, remaining_bytes);
+    int timeout = TIMEOUT;
+    while (poll_socket_modify_timeout(sockfd, &timeout)) {
+      size_t received_bytes = recv_datagram(sockfd, buffer, server_address);
+      if (received_bytes == 0) continue;
+      sscanf(buffer, "DATA %ld %ld\n", &recv_pos, &recv_len);
+      if (recv_pos < bytes_writen) continue;
+      
+      int pos = (recv_pos - bytes_writen) / DATAGRAM_LEN;
+      pos = (pos + w.first_pos) % w.size;
+      if (!w.uptodate[pos]) {
+        for (int i = 0; i < recv_len; i++) {
+          w.ar[pos][i] = buffer[i + received_bytes - recv_len];
+        }
+        w.uptodate[pos] = true;
+      }
+      update_file(fd, &w, &bytes_writen, &remaining_bytes);
+    }
+
+    if (prev_len != bytes_writen) {
+      prev_len = bytes_writen;
+      printf("%.3f%%\n", 100.0 * (float)(bytes_writen) / (float)(remaining_bytes+bytes_writen));
+    }
+  }
+  destroy_window(&w);
+  fclose(fd);
+}
+
+int main(int argc, char *argv[]) {
+  if (argc != 5) {
+    printf("Usage:\n\t%s [server ip] [server port] [output file name] [file size]\n", argv[0]);
+    return -1;
+  }
+
+  int sockfd = get_socket();
+  struct sockaddr_in server_address;
+  bzero(&server_address, sizeof(server_address));
+  server_address.sin_family = AF_INET;
+  if (!inet_pton(AF_INET, argv[1], &server_address.sin_addr)) {
+    fprintf(stderr, "Invalid ip address: %s\n", argv[1]);
+    return -1;
+  }
+  server_address.sin_port = htons(atoi(argv[2]));
+  if (server_address.sin_port == 0) {
+    fprintf(stderr, "Invalid port: %s\n", argv[2]);
+    return -1;
+  }
+
+  size_t file_len = atoi(argv[4]);
+  if (file_len == 0) {
+    printf("File len is 0, nothing to do here.\n");
+    return 0;
+  }
+
+  receive_file(sockfd, server_address, argv[3], file_len);
+}
\ No newline at end of file
diff --git a/semestr-4/sieci/pracownia3/franciszek_malinka/utils.c b/semestr-4/sieci/pracownia3/franciszek_malinka/utils.c
new file mode 100644
index 0000000..4c2f449
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/franciszek_malinka/utils.c
@@ -0,0 +1,58 @@
+/* Projekt: Transport
+ * Autor: Franciszek Malinka 316093
+ */
+
+#include "utils.h"
+#include <poll.h>
+#include <errno.h>
+#include <stdio.h>
+#include <netinet/ip.h>
+#include <arpa/inet.h>
+#include <stdlib.h>
+#include <string.h>
+
+size_t min(size_t x, size_t y) { return (x<y ? x : y); }
+
+int get_socket() {
+  int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
+  if (sockfd < 0) {
+    fprintf(stderr, "socket error: %s", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  return sockfd;
+}
+
+long get_time_interval(struct timespec start, struct timespec finish) {
+  return S_TO_MS(finish.tv_sec - start.tv_sec) + NS_TO_MS(finish.tv_nsec - start.tv_nsec);
+}
+
+int poll_socket_modify_timeout(int sockfd, int *timeout) {
+  if (*timeout < 0) {
+    *timeout = 0;
+    return 0;
+  }
+
+  struct pollfd fds;
+  struct timespec start;
+  struct timespec finish;
+  
+  fds.fd = sockfd;
+  fds.events = POLLIN;
+  fds.revents = 0;
+  
+  clock_gettime(CLOCK_REALTIME, &start);
+  int result = poll(&fds, 1, *timeout);
+  clock_gettime(CLOCK_REALTIME, &finish);
+  
+  if (result == -1) {
+    fprintf(stderr, "poll error: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  if (result == 0) {
+    *timeout = 0;
+    return 0;
+  }
+
+  *timeout -= get_time_interval(start, finish);
+  return result;
+}
diff --git a/semestr-4/sieci/pracownia3/franciszek_malinka/utils.h b/semestr-4/sieci/pracownia3/franciszek_malinka/utils.h
new file mode 100644
index 0000000..eccf347
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/franciszek_malinka/utils.h
@@ -0,0 +1,18 @@
+#ifndef UTILS_H
+#define UTILS_H
+
+#include <stddef.h>
+#include <time.h>
+
+#define NS_TO_MS(X) ((long)(X) / (long)1000000)
+#define S_TO_MS(X) ((long)(X) * (long)1000)
+
+size_t min(size_t x, size_t y);
+
+int get_socket();
+
+long get_time_interval(struct timespec start, struct timespec finish);
+
+int poll_socket_modify_timeout(int sockfd, int *timeout);
+
+#endif
\ No newline at end of file
diff --git a/semestr-4/sieci/pracownia3/franciszek_malinka/window.c b/semestr-4/sieci/pracownia3/franciszek_malinka/window.c
new file mode 100644
index 0000000..c8bffad
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/franciszek_malinka/window.c
@@ -0,0 +1,42 @@
+/* Projekt: Transport
+ * Autor: Franciszek Malinka 316093
+ */
+
+#include "window.h"
+#include <stdlib.h>
+#include <strings.h>
+
+void init_window(window_t *w, int window_size, int window_width) {
+  w->ar = malloc(window_size * sizeof(char *));
+  for (int i = 0; i < window_size; i++) 
+    w->ar[i] = malloc(window_width * sizeof(char));
+  w->uptodate = malloc(window_size);
+  bzero (w->uptodate, window_size);
+  w->first_pos = 0;
+  w->size = window_size;
+}
+
+void destroy_window(window_t *w) {
+  for (int i = 0; i < w->size; i++) 
+    free(w->ar[i]);
+  free(w->ar);
+  free(w->uptodate);
+}
+
+void shift_while_uptodate(window_t *w) {
+  while (w->uptodate[w->first_pos]) {
+    w->uptodate[w->first_pos] = false;
+    w->first_pos = (w->first_pos + 1) % w->size;
+  }
+}
+
+void shift(window_t *w) {
+  w->uptodate[w->first_pos] = false;
+  w->first_pos = (w->first_pos + 1) % w->size;
+}
+
+void update(window_t *w, int pos, char *buffer, size_t buf_size) {
+  pos = (w->first_pos + pos) % w->size;
+  for (int i = 0; i < buf_size; i++) w->ar[pos][i] = buffer[i];
+  w->uptodate[pos] = true;
+}
\ No newline at end of file
diff --git a/semestr-4/sieci/pracownia3/franciszek_malinka/window.h b/semestr-4/sieci/pracownia3/franciszek_malinka/window.h
new file mode 100644
index 0000000..63e89cc
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/franciszek_malinka/window.h
@@ -0,0 +1,24 @@
+#ifndef WINDOW_H
+#define WINDOW_H
+
+#include <stdbool.h>
+#include <stddef.h>
+
+typedef struct {
+  char **ar;
+  bool *uptodate;
+  int size;
+  int first_pos;
+} window_t;
+
+void init_window(window_t *w, int window_size, int window_width);
+
+void destroy_window(window_t *w);
+
+void shift_while_uptodate(window_t *w);
+
+void shift(window_t *w);
+
+void update(window_t *w, int pos, char *buffer, size_t buf_size);
+
+#endif
\ No newline at end of file
diff --git a/semestr-4/sieci/pracownia3/p3.pdf b/semestr-4/sieci/pracownia3/p3.pdf
new file mode 100644
index 0000000..14f1261
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/p3.pdf
diff --git a/semestr-4/sieci/pracownia3/transport.c b/semestr-4/sieci/pracownia3/transport.c
new file mode 100644
index 0000000..9226d69
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/transport.c
@@ -0,0 +1,149 @@
+/* Projekt: Transport
+ * Autor: Franciszek Malinka 316093
+ */
+
+#include <netinet/ip.h>
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <stdbool.h>
+#include "config.h"
+#include "window.h"
+#include "utils.h"
+
+size_t send_datagram(int sockfd, struct sockaddr_in server_address, char *buffer, size_t buffer_len) {
+  return sendto(sockfd, buffer, buffer_len, 0, (struct sockaddr*) &server_address, sizeof(server_address));
+}
+
+void send_data_request(int sockfd, struct sockaddr_in server_address, size_t pos, size_t bytes) {
+  char buffer[40];
+  sprintf(buffer, "GET %ld %ld\n", pos, bytes);
+  size_t buffer_len = strlen(buffer);
+  if (send_datagram(sockfd, server_address, buffer, buffer_len) != buffer_len) {
+    fprintf(stderr, "sendto error: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+}
+
+size_t recv_message(int sockfd, char *buffer, struct sockaddr_in *sender) {
+  socklen_t sender_len = sizeof(*sender);
+  bzero(buffer, HEADER_LEN + DATAGRAM_LEN);
+  bzero(sender, sizeof(*sender));
+  size_t datagram_len = recvfrom(sockfd, buffer, IP_MAXPACKET, 0,
+    (struct sockaddr*)sender, &sender_len);
+
+  if (datagram_len < 0) {
+    fprintf(stderr, "recvfrom error: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  
+  return datagram_len;
+}
+
+void request_data(int sockfd, struct sockaddr_in server_address, window_t *w, size_t bytes_writen, size_t remaining_bytes) {
+  int pos = w->first_pos;
+  for (int i = 0; i < w->size && i*DATAGRAM_LEN < remaining_bytes; i++) {
+    if (w->uptodate[pos] == false) {
+      size_t bytes_to_request = min(DATAGRAM_LEN, remaining_bytes - i*DATAGRAM_LEN);
+      send_data_request(sockfd, server_address, bytes_writen + i*DATAGRAM_LEN, bytes_to_request);
+    }
+    pos = (pos + 1) % w->size;
+  }
+}
+
+void update_file(FILE *fd, window_t *w, size_t *bytes_writen, size_t *remaining_bytes) {
+  while (w->uptodate[w->first_pos] && *remaining_bytes > 0) {
+    // printf("Writing %ld\n", *bytes_writen);
+    size_t bytes_to_write = min(DATAGRAM_LEN, *remaining_bytes);
+    fwrite(w->ar[w->first_pos], sizeof(char), bytes_to_write, fd);  
+    *bytes_writen += bytes_to_write;
+    *remaining_bytes -= bytes_to_write;
+    shift(w);
+  } 
+}
+
+size_t recv_datagram(int sockfd, char *buffer, struct sockaddr_in server_address) {
+  struct sockaddr_in sender;
+  
+  size_t received_bytes = recv_message(sockfd, buffer, &sender);
+  if (sender.sin_addr.s_addr != server_address.sin_addr.s_addr || sender.sin_port != server_address.sin_port) {
+    printf("Smieci!\n");
+    return 0;
+  }
+  return received_bytes;  
+}
+
+
+void receive_file(int sockfd, struct sockaddr_in server_address, const char *file_name, size_t remaining_bytes) {
+  FILE *fd = fopen(file_name, "w");
+  if (!fd) {
+    fprintf(stderr, "fopen error: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  size_t bytes_writen = 0;
+  
+  size_t recv_pos, recv_len;
+  char buffer[DATAGRAM_LEN + HEADER_LEN];
+  int prev_len = 0;
+  window_t w;
+  init_window(&w, WINDOW_SIZE, DATAGRAM_LEN);
+  
+  while (remaining_bytes) {
+    request_data(sockfd, server_address, &w, bytes_writen, remaining_bytes);
+    int timeout = TIMEOUT;
+    while (poll_socket_modify_timeout(sockfd, &timeout)) {
+      size_t received_bytes = recv_datagram(sockfd, buffer, server_address);
+      if (received_bytes == 0) continue;
+      sscanf(buffer, "DATA %ld %ld\n", &recv_pos, &recv_len);
+      if (recv_pos < bytes_writen) continue;
+      
+      int pos = (recv_pos - bytes_writen) / DATAGRAM_LEN;
+      pos = (pos + w.first_pos) % w.size;
+      if (!w.uptodate[pos]) {
+        for (int i = 0; i < recv_len; i++) {
+          w.ar[pos][i] = buffer[i + received_bytes - recv_len];
+        }
+        w.uptodate[pos] = true;
+      }
+      update_file(fd, &w, &bytes_writen, &remaining_bytes);
+    }
+
+    if (prev_len != bytes_writen) {
+      prev_len = bytes_writen;
+      printf("%.3f%%\n", 100.0 * (float)(bytes_writen) / (float)(remaining_bytes+bytes_writen));
+    }
+  }
+  destroy_window(&w);
+  fclose(fd);
+}
+
+int main(int argc, char *argv[]) {
+  if (argc != 5) {
+    printf("Usage:\n\t%s [server ip] [server port] [output file name] [file size]\n", argv[0]);
+    return -1;
+  }
+
+  int sockfd = get_socket();
+  struct sockaddr_in server_address;
+  bzero(&server_address, sizeof(server_address));
+  server_address.sin_family = AF_INET;
+  if (!inet_pton(AF_INET, argv[1], &server_address.sin_addr)) {
+    fprintf(stderr, "Invalid ip address: %s\n", argv[1]);
+    return -1;
+  }
+  server_address.sin_port = htons(atoi(argv[2]));
+  if (server_address.sin_port == 0) {
+    fprintf(stderr, "Invalid port: %s\n", argv[2]);
+    return -1;
+  }
+
+  size_t file_len = atoi(argv[4]);
+  if (file_len == 0) {
+    printf("File len is 0, nothing to do here.\n");
+    return 0;
+  }
+
+  receive_file(sockfd, server_address, argv[3], file_len);
+}
\ No newline at end of file
diff --git a/semestr-4/sieci/pracownia3/utils.c b/semestr-4/sieci/pracownia3/utils.c
new file mode 100644
index 0000000..4c2f449
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/utils.c
@@ -0,0 +1,58 @@
+/* Projekt: Transport
+ * Autor: Franciszek Malinka 316093
+ */
+
+#include "utils.h"
+#include <poll.h>
+#include <errno.h>
+#include <stdio.h>
+#include <netinet/ip.h>
+#include <arpa/inet.h>
+#include <stdlib.h>
+#include <string.h>
+
+size_t min(size_t x, size_t y) { return (x<y ? x : y); }
+
+int get_socket() {
+  int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
+  if (sockfd < 0) {
+    fprintf(stderr, "socket error: %s", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  return sockfd;
+}
+
+long get_time_interval(struct timespec start, struct timespec finish) {
+  return S_TO_MS(finish.tv_sec - start.tv_sec) + NS_TO_MS(finish.tv_nsec - start.tv_nsec);
+}
+
+int poll_socket_modify_timeout(int sockfd, int *timeout) {
+  if (*timeout < 0) {
+    *timeout = 0;
+    return 0;
+  }
+
+  struct pollfd fds;
+  struct timespec start;
+  struct timespec finish;
+  
+  fds.fd = sockfd;
+  fds.events = POLLIN;
+  fds.revents = 0;
+  
+  clock_gettime(CLOCK_REALTIME, &start);
+  int result = poll(&fds, 1, *timeout);
+  clock_gettime(CLOCK_REALTIME, &finish);
+  
+  if (result == -1) {
+    fprintf(stderr, "poll error: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  if (result == 0) {
+    *timeout = 0;
+    return 0;
+  }
+
+  *timeout -= get_time_interval(start, finish);
+  return result;
+}
diff --git a/semestr-4/sieci/pracownia3/utils.h b/semestr-4/sieci/pracownia3/utils.h
new file mode 100644
index 0000000..eccf347
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/utils.h
@@ -0,0 +1,18 @@
+#ifndef UTILS_H
+#define UTILS_H
+
+#include <stddef.h>
+#include <time.h>
+
+#define NS_TO_MS(X) ((long)(X) / (long)1000000)
+#define S_TO_MS(X) ((long)(X) * (long)1000)
+
+size_t min(size_t x, size_t y);
+
+int get_socket();
+
+long get_time_interval(struct timespec start, struct timespec finish);
+
+int poll_socket_modify_timeout(int sockfd, int *timeout);
+
+#endif
\ No newline at end of file
diff --git a/semestr-4/sieci/pracownia3/window.c b/semestr-4/sieci/pracownia3/window.c
new file mode 100644
index 0000000..c8bffad
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/window.c
@@ -0,0 +1,42 @@
+/* Projekt: Transport
+ * Autor: Franciszek Malinka 316093
+ */
+
+#include "window.h"
+#include <stdlib.h>
+#include <strings.h>
+
+void init_window(window_t *w, int window_size, int window_width) {
+  w->ar = malloc(window_size * sizeof(char *));
+  for (int i = 0; i < window_size; i++) 
+    w->ar[i] = malloc(window_width * sizeof(char));
+  w->uptodate = malloc(window_size);
+  bzero (w->uptodate, window_size);
+  w->first_pos = 0;
+  w->size = window_size;
+}
+
+void destroy_window(window_t *w) {
+  for (int i = 0; i < w->size; i++) 
+    free(w->ar[i]);
+  free(w->ar);
+  free(w->uptodate);
+}
+
+void shift_while_uptodate(window_t *w) {
+  while (w->uptodate[w->first_pos]) {
+    w->uptodate[w->first_pos] = false;
+    w->first_pos = (w->first_pos + 1) % w->size;
+  }
+}
+
+void shift(window_t *w) {
+  w->uptodate[w->first_pos] = false;
+  w->first_pos = (w->first_pos + 1) % w->size;
+}
+
+void update(window_t *w, int pos, char *buffer, size_t buf_size) {
+  pos = (w->first_pos + pos) % w->size;
+  for (int i = 0; i < buf_size; i++) w->ar[pos][i] = buffer[i];
+  w->uptodate[pos] = true;
+}
\ No newline at end of file
diff --git a/semestr-4/sieci/pracownia3/window.h b/semestr-4/sieci/pracownia3/window.h
new file mode 100644
index 0000000..63e89cc
--- /dev/null
+++ b/semestr-4/sieci/pracownia3/window.h
@@ -0,0 +1,24 @@
+#ifndef WINDOW_H
+#define WINDOW_H
+
+#include <stdbool.h>
+#include <stddef.h>
+
+typedef struct {
+  char **ar;
+  bool *uptodate;
+  int size;
+  int first_pos;
+} window_t;
+
+void init_window(window_t *w, int window_size, int window_width);
+
+void destroy_window(window_t *w);
+
+void shift_while_uptodate(window_t *w);
+
+void shift(window_t *w);
+
+void update(window_t *w, int pos, char *buffer, size_t buf_size);
+
+#endif
\ No newline at end of file