From 4167f191cec04314082896ca4618663e97b4f4f1 Mon Sep 17 00:00:00 2001
From: Franciszek Malinka <franciszek.malinka@gmail.com>
Date: Sun, 18 Apr 2021 10:26:08 +0200
Subject: Router modularity

---
 Semestr 4/sieci/pracownia2/router/utils.c | 90 +++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 Semestr 4/sieci/pracownia2/router/utils.c

(limited to 'Semestr 4/sieci/pracownia2/router/utils.c')

diff --git a/Semestr 4/sieci/pracownia2/router/utils.c b/Semestr 4/sieci/pracownia2/router/utils.c
new file mode 100644
index 0000000..9f008eb
--- /dev/null
+++ b/Semestr 4/sieci/pracownia2/router/utils.c	
@@ -0,0 +1,90 @@
+#include "utils.h"
+#include <arpa/inet.h>
+#include <netinet/ip.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+int get_socket() {
+  int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
+  if (sockfd < 0) {
+    fprintf(stderr, "Socket error: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  return sockfd;
+}
+
+void bind_to_port(int sockfd, uint16_t port) {
+  struct sockaddr_in server_address;
+  bzero(&server_address, sizeof(server_address));
+  server_address.sin_family       = AF_INET;
+  server_address.sin_port         = htons(port);
+  server_address.sin_addr.s_addr  = htonl(INADDR_ANY);
+  if (bind(sockfd, (struct sockaddr*)&server_address, sizeof(server_address)) < 0) {
+    fprintf(stderr, "Bind error: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  int broadcastPermission = 1;
+  setsockopt (sockfd, SOL_SOCKET, SO_BROADCAST, (void *)&broadcastPermission, sizeof(broadcastPermission));
+}
+
+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) {
+    fprintf(stderr, "poll_modify_timeout: timeout is negative.\n");
+    exit(EXIT_FAILURE);
+  }
+  
+  struct pollfd fds;
+  fds.fd = sockfd;
+  fds.events = POLLIN;
+  fds.revents = 0;
+
+  struct timespec start;
+  clock_gettime(CLOCK_REALTIME, &start);
+  int result = poll(&fds, 1, *timeout);
+  
+  if (result == -1) {
+    fprintf(stderr, "poll error: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  if (result == 0) {
+    *timeout = 0;
+    return 0;
+  }
+  struct timespec finish;
+  clock_gettime(CLOCK_REALTIME, &finish);
+  *timeout -= get_time_interval(start, finish);
+  printf("Timeout: %dms, time waiting: %ldms.\n", *timeout, get_time_interval(start, finish));
+  return result;
+}   
+
+/* For debug purposes only */
+void recv_and_print(int sockfd, int networks_number, struct router_addr *networks) {
+  struct sockaddr_in  sender;
+  socklen_t           sender_len = sizeof(sender);
+  uint8_t             buffer[IP_MAXPACKET + 1];
+  ssize_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);
+  }
+  for (int i = 0; i < networks_number; i++) {
+    if (networks[i].addr.s_addr == sender.sin_addr.s_addr) {
+      return;
+    }
+  }
+ 
+  char sender_ip_str[20];
+  inet_ntop(AF_INET, &(sender.sin_addr), sender_ip_str, sizeof(sender_ip_str));
+  printf("Received UDP packet from IP address: %s, port %d\n", 
+    sender_ip_str, ntohs(sender.sin_port));
+
+  buffer[datagram_len] = 0;
+  printf("%ld-byte message: +%s+\n", datagram_len, buffer);
+}
\ No newline at end of file
-- 
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