Traceroute skonczony

1 files changed, 139 insertions, 20 deletions

diff --git a/Semestr 4/sieci/pracownia1/traceroute.c b/Semestr 4/sieci/pracownia1/traceroute.c
index 88d233a..9281e4f 100644
--- a/Semestr 4/sieci/pracownia1/traceroute.c
+++ b/Semestr 4/sieci/pracownia1/traceroute.c
@@ -8,9 +8,14 @@
 #include <netinet/ip_icmp.h>
 #include <assert.h>
 #include <time.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdbool.h>
 
 #define MAX_TTL 30
 #define MESSAGES_PER_TTL 3
+#define NO_MESSAGES -1
+#define TOO_FEW_MESSAGES -2137
 
 void print_as_bytes (unsigned char* buff, ssize_t length)
 {
@@ -38,7 +43,7 @@ int create_raw_icmp_socket() {
     return sockfd;
 }
 
-uint16_t compute_icmp_checksum (const void *buff, int length)
+uint16_t compute_icmp_checksum(const void *buff, int length)
 {
 	uint32_t sum;
 	const uint16_t* ptr = buff;
@@ -49,15 +54,12 @@ uint16_t compute_icmp_checksum (const void *buff, int length)
 	return (uint16_t)(~(sum + (sum >> 16)));
 }
 
-struct icmp create_icmp_header() {
-    static uint16_t pid = 0;
-    static uint16_t seq = 0;
-    
+struct icmp create_icmp_header(uint16_t seq) {    
     struct icmp header;
     header.icmp_type = ICMP_ECHO;
     header.icmp_code = 0;
-    header.icmp_id = ++pid;
-    header.icmp_seq = ++seq;
+    header.icmp_id = (uint16_t)getpid();
+    header.icmp_seq = seq;
     header.icmp_cksum = 0;
     header.icmp_cksum = compute_icmp_checksum(
         (uint16_t*)&header, sizeof(header));
@@ -66,10 +68,10 @@ struct icmp create_icmp_header() {
 }
 
 void send_icmp_packet(int sockfd, struct sockaddr_in *destination, int ttl) {
-    struct icmp header = create_icmp_header();
+    struct icmp header = create_icmp_header(ttl);
     setsockopt(sockfd, IPPROTO_IP, IP_TTL, &ttl, sizeof(int));
 
-    printf("%ld %d\n", destination->sin_addr.s_addr, sockfd);
+    // printf("%u %d\n", destination->sin_addr.s_addr, sockfd);
     ssize_t bytes_sent = sendto(
         sockfd,
         &header,
@@ -82,31 +84,146 @@ 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);
+    // fprintf(stdout, "Bytes sent: %ld\n", bytes_sent);
 }
 
 /* Return ip address of the sender of recceived package */
-in_addr_t recv_dontwait(int sockfd) {
-    struct sockaddr_in       sender;
-    socklen_t sender_len =   sizeof(sender);
-    uint8_t                  buffer[IP_MAXPACKET];
+ssize_t recv_packet(int sockfd, struct sockaddr_in *sender, uint8_t *buffer) {
+    socklen_t sender_len =   sizeof(*sender);
 
-    ssize_t packet_len = recvfrom(sockfd, buffer, IP_MAXPACKET, MSG_DONTWAIT,
-        (struct sockaddr*)&sender, &sender_len);
+    ssize_t packet_len = recvfrom(sockfd, buffer, IP_MAXPACKET, 0,
+        (struct sockaddr*)sender, &sender_len);
     
     if (packet_len == -1) {
         fprintf(stderr, "Error while recieving a packet: %s\n", strerror(errno));
         exit(EXIT_FAILURE);
     }
+    return packet_len;
+}
+
+void send_icmp_requests(int sockfd, struct sockaddr_in *destination, int ttl, int tries) {
+    for (int i = 0; i < tries; i++) {
+        send_icmp_packet(sockfd, destination, ttl);
+    }
+}
+
+int try_select(int sockfd, struct timeval *tv) {
+    fd_set descriptors;
+    FD_ZERO(&descriptors);
+    FD_SET(sockfd, &descriptors);
+    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) {
+    char ip_str[20];
+    printf("%d.\t", ttl);
+    if (messages_recieved == 0) {
+        printf("*\n");
+    }
+    else {
+        for (int i = 0; i < messages_recieved; i++) {
+            bool already_printed = false;
+            for (int j = 0; j < i; j++) {
+                if (senders[i].s_addr == senders[j].s_addr) {
+                    already_printed = true;
+                    break;
+                }
+            }
+            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");
+        else                                        printf("\t%.2fms\n", mean_wait_time);
+    }
+}
+
+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) {
+        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;
+    }
+}
 
-    return sender.sin_addr.s_addr;
+// timeout in milliseconds
+float get_replies(int sockfd, long timeout, int ttl, int *messages_recieved, 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;
+
+    while ((ready = try_select(sockfd, &tv))) {
+        if (ready < 0) {
+            fprintf(stderr, "Select error: %s\n", strerror(errno));
+            exit(EXIT_FAILURE);
+        }
+
+        recv_packet(sockfd, &sender, buffer);
+        uint8_t         icmp_code = 0;
+        uint16_t        seq = 0, id = 0;
+
+        get_important_data(buffer, &icmp_code, &id, &seq);
+        if (seq == ttl) {
+            senders[(*messages_recieved)++] = sender.sin_addr;
+            mean_wait_time += timeout * 1000 - tv.tv_usec;
+            
+            if (*messages_recieved == MESSAGES_PER_TTL) break;
+        }
+    }
+    // changing from microseconds to miliseconds
+    return (float)mean_wait_time / 3.0 / 1000.0;
 }
 
-int traceroute(struct sockaddr_in *destination) {
-    int sockfd = create_raw_icmp_socket();
+void traceroute(struct sockaddr_in *destination) {
+    int sockfd = create_raw_icmp_socket(), messages_recieved = 0;
+    struct in_addr senders[MESSAGES_PER_TTL];
 
     for (int ttl = 1; ttl <= MAX_TTL; ++ttl) {
-        send_icmp_packet(sockfd, destination, 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++) {
+            if (senders[i].s_addr == destination->sin_addr.s_addr) {
+                return;
+            }
+        }
     }
 }     
 
@@ -118,4 +235,6 @@ int main(int argc, char * argv[]) {
 
     struct sockaddr_in destination = get_sockaddr_from_ip(argv[1]);
     traceroute(&destination);
+
+    return 0;
 }
\ No newline at end of file