1 files changed, 44 insertions, 44 deletions

diff --git a/Semestr 4/sieci/pracownia1/traceroute.c b/Semestr 4/sieci/pracownia1/traceroute.c
index 9281e4f..0e51c14 100644
--- a/Semestr 4/sieci/pracownia1/traceroute.c
+++ b/Semestr 4/sieci/pracownia1/traceroute.c
@@ -1,3 +1,8 @@
+/* Pracownia programistyczna nr 1 - traceroute
+ * Imię i nazwisko: Franciszek Malinka
+ * Nr indeksu:      316093
+ */
+
 #include <stdio.h>
 #include <errno.h>
 #include <netinet/ip.h>
@@ -23,6 +28,23 @@ void print_as_bytes (unsigned char* buff, ssize_t length)
 		printf ("%.2x ", *buff);	
 }
 
+void debug_received(uint8_t *buffer, struct sockaddr_in *sender, int packet_len) {
+    char ip_str[20];
+    inet_ntop(AF_INET, &(sender->sin_addr), ip_str, sizeof(ip_str));
+
+    printf("IP packet with ICMP content from: %s\n", ip_str);
+    struct ip*  ip_header = (struct ip*) buffer;
+    ssize_t     ip_header_len = 4 * ip_header->ip_hl;
+
+    printf ("IP header: "); 
+    print_as_bytes (buffer, ip_header_len);
+    printf("\n");
+
+    printf ("IP data:   ");
+    print_as_bytes (buffer + ip_header_len, packet_len - ip_header_len);
+    printf("\n\n");
+}
+
 struct sockaddr_in get_sockaddr_from_ip(char *ip) {
     struct sockaddr_in sock;
     bzero(&sock, sizeof(sock));
@@ -71,7 +93,6 @@ void send_icmp_packet(int sockfd, struct sockaddr_in *destination, int ttl) {
     struct icmp header = create_icmp_header(ttl);
     setsockopt(sockfd, IPPROTO_IP, IP_TTL, &ttl, sizeof(int));
 
-    // printf("%u %d\n", destination->sin_addr.s_addr, sockfd);
     ssize_t bytes_sent = sendto(
         sockfd,
         &header,
@@ -84,13 +105,11 @@ void send_icmp_packet(int sockfd, struct sockaddr_in *destination, int ttl) {
         fprintf(stderr, "Error while sending ICMP packet: %s\n", strerror(errno));
         exit(EXIT_FAILURE);
     }
-    // fprintf(stdout, "Bytes sent: %ld\n", bytes_sent);
 }
 
 /* Return ip address of the sender of recceived package */
 ssize_t recv_packet(int sockfd, struct sockaddr_in *sender, uint8_t *buffer) {
-    socklen_t sender_len =   sizeof(*sender);
-
+    socklen_t sender_len = sizeof(*sender);
     ssize_t packet_len = recvfrom(sockfd, buffer, IP_MAXPACKET, 0,
         (struct sockaddr*)sender, &sender_len);
     
@@ -114,36 +133,14 @@ int try_select(int sockfd, struct timeval *tv) {
     return select(sockfd+1, &descriptors, NULL, NULL, tv);
 }
 
-void in_addr_to_string(struct in_addr *sender, char *ip_str) {
-    inet_ntop(AF_INET, sender, ip_str, sizeof(ip_str));
-} 
-
-void debug_recieved(uint8_t *buffer, struct sockaddr_in *sender, int packet_len) {
-    char ip_str[20];
-    inet_ntop(AF_INET, &(sender->sin_addr), ip_str, sizeof(ip_str));
-
-    // in_addr_to_string(&(sender->sin_addr), ip_str);
-    printf("IP packet with ICMP content from: %s\n", ip_str);
-    struct ip*  ip_header = (struct ip*) buffer;
-    ssize_t     ip_header_len = 4 * ip_header->ip_hl;
-
-    printf ("IP header: "); 
-    print_as_bytes (buffer, ip_header_len);
-    printf("\n");
-
-    printf ("IP data:   ");
-    print_as_bytes (buffer + ip_header_len, packet_len - ip_header_len);
-    printf("\n\n");
-}
-
-void pretty_print_router(int ttl, struct in_addr *senders, float mean_wait_time, int messages_recieved) {
+void pretty_print_router(int ttl, struct in_addr *senders, float mean_wait_time, int messages_received) {
     char ip_str[20];
     printf("%d.\t", ttl);
-    if (messages_recieved == 0) {
+    if (messages_received == 0) {
         printf("*\n");
     }
     else {
-        for (int i = 0; i < messages_recieved; i++) {
+        for (int i = 0; i < messages_received; i++) {
             bool already_printed = false;
             for (int j = 0; j < i; j++) {
                 if (senders[i].s_addr == senders[j].s_addr) {
@@ -153,27 +150,25 @@ void pretty_print_router(int ttl, struct in_addr *senders, float mean_wait_time,
             }
             if (already_printed) continue;
             inet_ntop(AF_INET, senders + i, ip_str, sizeof(ip_str));
-            // in_addr_to_string(senders + i, ip_str);
             printf("%-15s ", ip_str);
         }
-        if (messages_recieved < MESSAGES_PER_TTL)   printf("\t???\n");
+        if (messages_received < MESSAGES_PER_TTL)   printf("\t???\n");
         else                                        printf("\t%.2fms\n", mean_wait_time);
     }
 }
 
+// This function decapsulates important data from the IMCP replies
 void get_important_data(uint8_t *buffer, uint8_t *code, uint16_t *id, uint16_t *seq) {
     struct ip*      ip_header = (struct ip*) buffer;
     ssize_t         offset = 4 * ip_header->ip_hl;
     *code = ((struct icmp *)(buffer + offset))->icmp_type;
-    if (*code == ICMP_TIMXCEED) {
+    if (*code != ICMP_ECHOREPLY && *code != ICMP_TIMXCEED) {
+        return;
+    } else if (*code == ICMP_TIMXCEED) {
         offset  += ICMP_MINLEN;
         offset  += 4 * ((struct ip *)(buffer + offset))->ip_hl;
         *seq    = ((struct icmp *)(buffer + offset))->icmp_seq;
         *id     = ((struct icmp *)(buffer + offset))->icmp_id;
-    }
-    else if (*code != ICMP_ECHOREPLY) {
-        fprintf(stderr, "Something went wrong, recieved ICMP packet with code %d\n.", *code);
-        exit(EXIT_FAILURE);
     } else {
         *seq = ((struct icmp *)(buffer + offset))->icmp_seq;
         *id = ((struct icmp *)(buffer + offset))->icmp_id;
@@ -181,13 +176,13 @@ void get_important_data(uint8_t *buffer, uint8_t *code, uint16_t *id, uint16_t *
 }
 
 // timeout in milliseconds
-float get_replies(int sockfd, long timeout, int ttl, int *messages_recieved, struct in_addr *senders) {
+float get_replies(int sockfd, long timeout, int ttl, int *messages_received, struct in_addr *senders) {
     struct sockaddr_in  sender;
     uint8_t             buffer[IP_MAXPACKET];
     int                 ready;
     long                mean_wait_time = 0;
     struct timeval      tv; tv.tv_sec = timeout / 1000; tv.tv_usec = 0;
-    *messages_recieved = 0;
+    *messages_received = 0;
 
     while ((ready = try_select(sockfd, &tv))) {
         if (ready < 0) {
@@ -201,25 +196,29 @@ float get_replies(int sockfd, long timeout, int ttl, int *messages_recieved, str
 
         get_important_data(buffer, &icmp_code, &id, &seq);
         if (seq == ttl) {
-            senders[(*messages_recieved)++] = sender.sin_addr;
+            senders[(*messages_received)++] = sender.sin_addr;
             mean_wait_time += timeout * 1000 - tv.tv_usec;
             
-            if (*messages_recieved == MESSAGES_PER_TTL) break;
+            if (*messages_received == MESSAGES_PER_TTL) break;
         }
     }
     // changing from microseconds to miliseconds
     return (float)mean_wait_time / 3.0 / 1000.0;
 }
 
+// Core of the program.
 void traceroute(struct sockaddr_in *destination) {
-    int sockfd = create_raw_icmp_socket(), messages_recieved = 0;
+    int sockfd = create_raw_icmp_socket(), messages_received = 0;
     struct in_addr senders[MESSAGES_PER_TTL];
 
     for (int ttl = 1; ttl <= MAX_TTL; ++ttl) {
         send_icmp_requests(sockfd, destination, ttl, MESSAGES_PER_TTL);
-        float mean_wait_time = get_replies(sockfd, 1000, ttl, &messages_recieved, senders);
-        pretty_print_router(ttl, senders, mean_wait_time, messages_recieved);
-        for (int i = 0; i < messages_recieved; i++) {
+        float mean_wait_time = get_replies(sockfd, 1000, ttl, &messages_received, senders);
+        pretty_print_router(ttl, senders, mean_wait_time, messages_received);
+
+        // what if our packet branched and we got to the destination faster by some path? 
+        // we gotta make a loop, not an if
+        for (int i = 0; i < messages_received; i++) {
             if (senders[i].s_addr == destination->sin_addr.s_addr) {
                 return;
             }
@@ -234,6 +233,7 @@ int main(int argc, char * argv[]) {
     }
 
     struct sockaddr_in destination = get_sockaddr_from_ip(argv[1]);
+    fprintf(stdout, "traceroute to %s, %d hops max\n", argv[1], MAX_TTL);
     traceroute(&destination);
 
     return 0;