Router modularity

5 files changed, 255 insertions, 0 deletions

diff --git a/Semestr 4/sieci/pracownia2/router/router.c b/Semestr 4/sieci/pracownia2/router/router.c
new file mode 100644
index 0000000..f68a6a3
--- /dev/null
+++ b/Semestr 4/sieci/pracownia2/router/router.c
@@ -0,0 +1,91 @@
+#include <stdio.h>
+#include <errno.h>
+#include <strings.h>
+#include <string.h>
+#include <netinet/ip.h>
+#include <arpa/inet.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include "router_addr.h"
+#include "utils.h"
+
+#define SERVER_PORT 54321
+#define TURN_LEN_S 5
+#define TURN_LEN_MS (1000 * TURN_LEN_S)
+#define TURN_LEN_US (1000000 * TURN_LEN_S)
+
+uint16_t read_configuration(struct router_addr** networks) {
+  uint16_t n;
+  scanf("%hd", &n);
+  *networks = malloc(n * sizeof(struct router_addr));
+  for (int i = 0; i < n; i++) {
+    char addr[20];
+    char _dist[10];
+    uint16_t dist;
+    scanf(" %s %s %hd", addr, _dist, &dist);
+    (*networks)[i] = stora(addr);
+    (*networks)[i].distance = dist;
+  }
+  return n;
+}
+
+void listen_for_routers(int sockfd, int timeout, int networks_number, struct router_addr *netowrks) {
+  printf("Listening for %dms.\n", timeout);
+  while (poll_socket_modify_timeout(sockfd, &timeout)) {
+    printf("Poll returned, remaining timeout: %dms.\n", timeout);
+    recv_and_print(sockfd, networks_number, netowrks);
+  }
+  printf("Finished listening\n\n");
+}
+
+int send_distance_vector(int sockfd, struct in_addr network) {
+  struct sockaddr_in network_address;
+  bzero (&network_address, sizeof(network_address));
+  network_address.sin_family       = AF_INET;
+  network_address.sin_port         = htons(SERVER_PORT);
+  network_address.sin_addr         = network;
+
+  char* message = "Hello server! My name is S1\n";
+  ssize_t message_len = strlen(message);
+  int result;
+
+  char addr[20];
+  inet_ntop(AF_INET, &network, addr, sizeof(addr));
+  printf("Sending datagram to %s\n", addr);
+  if ((result = sendto(sockfd, message, message_len, 0, (struct sockaddr*) &network_address, sizeof(network_address))) != message_len) {
+    fprintf(stderr, "sendto error: %s\n", strerror(errno));
+  }
+}
+
+void propagate_distance_vector(int sockfd, int networks_number, struct router_addr *networks) {
+  printf("Propagating distance vector\n");
+  for (int i = 0; i < networks_number; i++) {
+    struct in_addr broadcast_address = get_broadcast_address(networks[i]);
+    send_distance_vector(sockfd, broadcast_address);
+  }
+  printf("Distance vector propagated.\n\n");
+}
+
+void router_loop(int sockfd, int networks_number, struct router_addr *networks) {
+  printf("Starting the router loop...\n");
+  for (;;) {
+    listen_for_routers(sockfd, TURN_LEN_MS, networks_number, networks);
+    propagate_distance_vector(sockfd, networks_number, networks);
+  }
+}
+
+int main() {
+  struct router_addr* networks;
+  int n = read_configuration(&networks);
+  for (int i = 0; i < n; i++) {
+    pretty_print(networks[i]);
+  }
+
+  int sockfd = get_socket();
+  bind_to_port(sockfd, SERVER_PORT);
+  router_loop(sockfd, n, networks);
+
+  close(sockfd);
+  free(networks);
+}
\ No newline at end of file
diff --git a/Semestr 4/sieci/pracownia2/router/router_addr.c b/Semestr 4/sieci/pracownia2/router/router_addr.c
new file mode 100644
index 0000000..1e4c086
--- /dev/null
+++ b/Semestr 4/sieci/pracownia2/router/router_addr.c
@@ -0,0 +1,32 @@
+#include "router_addr.h"
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+struct in_addr get_broadcast_address(struct router_addr ra) {
+  struct in_addr result = ra.addr;
+  /* bitshift by more than 31 is UB */
+  if (ra.netmask < 32) {
+    result.s_addr |= ~((1<<ra.netmask) - 1);
+  }
+  return result;
+}
+
+void pretty_print(struct router_addr ra) {
+  char ip_addr[20];
+  inet_ntop(AF_INET, &ra.addr, ip_addr, sizeof(ip_addr));
+  printf("%s/%d distance %d\n", ip_addr, ra.netmask, ra.distance);
+}
+
+/* converts string of IP with netmask in CIDR notation to router_addr */
+struct router_addr stora(char *str) {
+  struct router_addr  result;
+  char                addr[20];
+  size_t              ip_preffix = strcspn(str, "/");
+  
+  strncpy(addr, str, strlen(str));
+  addr[ip_preffix] = 0;
+  inet_pton(AF_INET, addr, &(result.addr));
+  result.netmask = atoi(str + ip_preffix + 1);
+  return result;
+}
\ No newline at end of file
diff --git a/Semestr 4/sieci/pracownia2/router/router_addr.h b/Semestr 4/sieci/pracownia2/router/router_addr.h
new file mode 100644
index 0000000..bebb0f5
--- /dev/null
+++ b/Semestr 4/sieci/pracownia2/router/router_addr.h
@@ -0,0 +1,19 @@
+#ifndef ROUTER_ADDR_H
+#define ROUTER_ADDR_H
+
+#include <arpa/inet.h>
+#include <stdint.h>
+
+struct router_addr {
+  struct in_addr  addr;
+  uint16_t        distance;
+  uint8_t         netmask;
+};
+
+struct in_addr get_broadcast_address(struct router_addr ra);
+
+void pretty_print(struct router_addr ra);
+
+struct router_addr stora(char *str);
+
+#endif
\ No newline at end of file
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
diff --git a/Semestr 4/sieci/pracownia2/router/utils.h b/Semestr 4/sieci/pracownia2/router/utils.h
new file mode 100644
index 0000000..3d36aed
--- /dev/null
+++ b/Semestr 4/sieci/pracownia2/router/utils.h
@@ -0,0 +1,23 @@
+#ifndef UTILS_H
+#define UTILS_H
+#define UTILS_H
+
+#include <stdint.h>
+#include <time.h>
+#include <poll.h>
+#include "router_addr.h"
+
+#define NS_TO_MS(X) ((long)(X) / (long)1000000)
+#define S_TO_MS(X) ((long)(X) * (long)1000)
+
+int get_socket();
+
+void bind_to_port(int sockfd, uint16_t port);
+
+long get_time_interval(struct timespec start, struct timespec finish);
+
+int poll_socket_modify_timeout(int sockfd, int *timeout);
+
+void recv_and_print(int sockfd, int networks_number, struct router_addr *networks);
+
+#endif
\ No newline at end of file