From a11df2c963520c64768158c2753237152a1eae3d Mon Sep 17 00:00:00 2001
From: Franciszek Malinka <franciszek.malinka@gmail.com>
Date: Sat, 17 Apr 2021 17:31:46 +0200
Subject: Update

---
 Semestr 4/sieci/pracownia2/router.c     | 212 ++++++++++++++++++++++++++++++++
 Semestr 4/sieci/pracownia2/udp_client.c |  33 +++++
 Semestr 4/sieci/pracownia2/udp_server.c |  59 +++++++++
 3 files changed, 304 insertions(+)
 create mode 100644 Semestr 4/sieci/pracownia2/router.c
 create mode 100755 Semestr 4/sieci/pracownia2/udp_client.c
 create mode 100755 Semestr 4/sieci/pracownia2/udp_server.c

(limited to 'Semestr 4/sieci/pracownia2')

diff --git a/Semestr 4/sieci/pracownia2/router.c b/Semestr 4/sieci/pracownia2/router.c
new file mode 100644
index 0000000..79754b3
--- /dev/null
+++ b/Semestr 4/sieci/pracownia2/router.c	
@@ -0,0 +1,212 @@
+#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 <poll.h>
+#include <time.h>
+#include <unistd.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)
+#define NS_TO_MS(X) ((long)(X) / (long)1000000)
+#define S_TO_MS(X) ((long)(X) * (long)1000)
+
+struct router_addr {
+    struct in_addr  addr;
+    uint16_t        distance;
+    uint8_t         netmask;
+};
+
+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;
+}
+
+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));
+}
+
+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;
+}
+
+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_modify_timeout(struct pollfd *fds, nfds_t nfd, int *timeout) {
+    if (*timeout < 0) {
+        fprintf(stderr, "poll_modify_timeout: timeout is negative.\n");
+        exit(EXIT_FAILURE);
+    }
+    
+    struct timespec start;
+    clock_gettime(CLOCK_REALTIME, &start);
+    int result = poll(fds, nfd, *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);
+
+}
+
+void listen_for_routers(int sockfd, int timeout, int networks_number, struct router_addr *netowrks) {
+    printf("Listening for %dms.\n", timeout);
+    struct pollfd fds;
+    fds.fd = sockfd;
+    fds.events = POLLIN;
+    fds.revents = 0;
+    while (poll_modify_timeout(&fds, 1, &timeout)) {
+        printf("Poll returned, remaining timeout: %dms.\n", timeout);
+        recv_and_print(sockfd, networks_number, netowrks);
+    }
+    printf("Finished listening\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)); 
+		// return EXIT_FAILURE;		
+	}
+}
+
+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");
+}
+
+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/udp_client.c b/Semestr 4/sieci/pracownia2/udp_client.c
new file mode 100755
index 0000000..5624484
--- /dev/null
+++ b/Semestr 4/sieci/pracownia2/udp_client.c	
@@ -0,0 +1,33 @@
+#include <netinet/ip.h>
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+int main()
+{
+	int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
+	if (sockfd < 0) {
+		fprintf(stderr, "socket error: %s\n", strerror(errno)); 
+		return EXIT_FAILURE;
+	}
+
+	struct sockaddr_in server_address;
+	bzero (&server_address, sizeof(server_address));
+	server_address.sin_family      = AF_INET;
+	server_address.sin_port        = htons(54321);
+	inet_pton(AF_INET, "192.168.1.2", &server_address.sin_addr);
+
+	char* message = "Hello server!";
+	ssize_t message_len = strlen(message);
+	if (sendto(sockfd, message, message_len, 0, (struct sockaddr*) &server_address, sizeof(server_address)) != message_len) {
+		fprintf(stderr, "sendto error: %s\n", strerror(errno)); 
+		return EXIT_FAILURE;		
+	}
+
+	close (sockfd);
+	return EXIT_SUCCESS;
+}
+	
diff --git a/Semestr 4/sieci/pracownia2/udp_server.c b/Semestr 4/sieci/pracownia2/udp_server.c
new file mode 100755
index 0000000..b5ae6d1
--- /dev/null
+++ b/Semestr 4/sieci/pracownia2/udp_server.c	
@@ -0,0 +1,59 @@
+#include <netinet/ip.h>
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+int main()
+{
+	int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
+	if (sockfd < 0) {
+		fprintf(stderr, "socket error: %s\n", strerror(errno)); 
+		return EXIT_FAILURE;
+	}
+
+	struct sockaddr_in server_address;
+	bzero (&server_address, sizeof(server_address));
+	server_address.sin_family      = AF_INET;
+	server_address.sin_port        = htons(54321);
+	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)); 
+		return EXIT_FAILURE;
+	}
+
+	for (;;) {
+
+		struct sockaddr_in 	sender;	
+		socklen_t 			sender_len = sizeof(sender);
+		u_int8_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)); 
+			return EXIT_FAILURE;
+		}
+		
+		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);
+		
+		char* reply = "Thank you!";
+		ssize_t reply_len = strlen(reply);
+		if (sendto(sockfd, reply, reply_len, 0, (struct sockaddr*)&sender, sender_len) != reply_len) {
+			fprintf(stderr, "sendto error: %s\n", strerror(errno)); 
+			return EXIT_FAILURE;		
+		}
+
+		fflush(stdout);
+	}
+
+	close (sockfd);
+	return EXIT_SUCCESS;
+}
+
-- 
cgit v1.2.3