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P8/prueba.c

+/**
+ * Practica Tema 8: ICMP-TIMESTAMP
+ *
+ * Redondo Calleja, Daniel
+ * Jimenez Prieto, Roberto
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <sys/time.h>
+#include "ip-icmp.h"
+
+#define ICMP_TIMESTAMP 13
+#define ICMP_TIMESTAMP_REPLY 14
+#define TIMEOUT 5 // Tiempo de espera en segundos
+
+void crearICMPRequest(TimeStamp *icmp_msg);
+unsigned short checksum(void *b, int len);
+void imprimeError(unsigned char type, unsigned char code);
+
+int main(int argc, char *argv[]) {
+    if (argc < 2 || argc > 3) {
+        fprintf(stderr, "Uso: %s ip [-v]\n", argv[0]);
+        exit(EXIT_FAILURE);
+    }
+
+    int verbose = (argc == 3 && strcmp(argv[2], "-v") == 0);
+    const char *ip = argv[1];
+    int sockfd;
+    struct sockaddr_in dest_addr, local_addr;
+
+    // Crear socket RAW para ICMP
+    sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
+    if (sockfd < 0) {
+        perror("Error al crear el socket");
+        exit(EXIT_FAILURE);
+    }
+
+    memset(&dest_addr, 0, sizeof(dest_addr));
+    dest_addr.sin_family = AF_INET;
+    dest_addr.sin_port = 0; // Inicializar sin_port
+    if (inet_pton(AF_INET, ip, &dest_addr.sin_addr) <= 0) {
+        perror("Error al convertir la dirección IP");
+        close(sockfd);
+        exit(EXIT_FAILURE);
+    }
+
+    // Asociar socket a la dirección local
+    memset(&local_addr, 0, sizeof(local_addr));
+    local_addr.sin_family = AF_INET;
+    local_addr.sin_addr.s_addr = INADDR_ANY;
+    local_addr.sin_port = 0;
+    if (bind(sockfd, (struct sockaddr *)&local_addr, sizeof(local_addr)) < 0) {
+        perror("Error al asociar el socket a la dirección local");
+        close(sockfd);
+        exit(EXIT_FAILURE);
+    }
+
+    // Construir el mensaje ICMP
+    TimeStamp icmp_msg;
+    crearICMPRequest(&icmp_msg);
+
+    // En modo verbose, imprime los detalles del datagrama enviado
+    if (verbose) {
+        printf("-> Type: %d\n", icmp_msg.icmpHdr.type);
+        printf("-> Code: %d\n", icmp_msg.icmpHdr.code);
+        printf("-> PID : %d\n", icmp_msg.pid);
+        printf("-> Seq Numbr: %d\n", ntohs(icmp_msg.sequence));
+        printf("-> Originate: %u ms\n", icmp_msg.originate);
+        printf("-> Receive: 0 ms\n");
+        printf("-> Transmit: 0 ms\n");
+        printf("-> Tamanyo del Datagrama: %ld bytes\n", sizeof(TimeStamp));
+    }
+
+    // Enviar mensaje ICMP
+    printf("-> Enviando Datagrama ICMP a Destino con IP: %s\n", ip);
+    if (sendto(sockfd, &icmp_msg, sizeof(icmp_msg), 0, (struct sockaddr *)&dest_addr, sizeof(dest_addr)) < 0) {
+        perror("Error al enviar el datagrama");
+        close(sockfd);
+        exit(EXIT_FAILURE);
+    }
+    printf("-> Timestamp Request enviado correctamente...\n");
+
+    // Configurar timeout
+    fd_set readfds;
+    FD_ZERO(&readfds);
+    FD_SET(sockfd, &readfds);
+
+    struct timeval timeout = {TIMEOUT, 0};
+    int sel = select(sockfd + 1, &readfds, NULL, NULL, &timeout);
+    if (sel < 0) {
+        perror("Error en select");
+        close(sockfd);
+        exit(EXIT_FAILURE);
+    } else if (sel == 0) {
+        printf("-> Tiempo de espera agotado para %s\n", ip);
+        close(sockfd);
+        exit(EXIT_FAILURE);
+    }
+
+    // Recibir respuesta
+    TimeStampReply recv_reply;
+    socklen_t addr_len = sizeof(dest_addr);
+    if (recvfrom(sockfd, &recv_reply, sizeof(recv_reply), 0, (struct sockaddr *)&dest_addr, &addr_len) < 0) {
+        perror("Error al recibir el datagrama");
+        close(sockfd);
+        exit(EXIT_FAILURE);
+    }
+
+    // Verificar tipo de respuesta
+    printf("\n-> Timestamp Reply recibido desde %s\n", ip);
+    if (recv_reply.icmpMsg.icmpHdr.type == ICMP_TIMESTAMP_REPLY && recv_reply.icmpMsg.icmpHdr.code == 0) {
+        int originate = recv_reply.icmpMsg.originate;
+        int receive = recv_reply.icmpMsg.receive;
+        int transmit = recv_reply.icmpMsg.transmit;
+
+        struct timeval end_time;
+        gettimeofday(&end_time, NULL);
+        int t4 = (end_time.tv_sec * 1000) + (end_time.tv_usec / 1000);
+        int rtt = (receive - originate) + (t4 - transmit);
+
+        if (verbose) {
+            printf("-> Originate: %u ms\n", originate);
+            printf("-> Receive: %u ms\n", receive);
+            printf("-> Transmit: %u ms\n", transmit);
+            printf("-> RTT: %u ms\n", rtt);
+            printf("-> TTL: %d\n", recv_reply.ipHdr.TTL);
+            printf("-> Tamanyo del Datagrama: %ld bytes\n", sizeof(TimeStampReply));
+        }
+
+        printf("-> Respuesta Correcta (Type %d, Code %d)\n", recv_reply.icmpMsg.icmpHdr.type, recv_reply.icmpMsg.icmpHdr.code);
+    } else if (recv_reply.icmpMsg.icmpHdr.type == 3){
+        imprimeError(recv_reply.icmpMsg.icmpHdr.type, recv_reply.icmpMsg.icmpHdr.code);
+    }else {
+        printf("-> ICMP Datagram Not Processed...\n");
+    }
+
+    close(sockfd);
+    return EXIT_SUCCESS;
+}
+
+void crearICMPRequest(TimeStamp *icmp_msg) {
+    memset(icmp_msg, 0, sizeof(TimeStamp));
+    icmp_msg->icmpHdr.type = ICMP_TIMESTAMP;
+    icmp_msg->icmpHdr.code = 0;
+    icmp_msg->pid = getpid();
+    icmp_msg->sequence = htons(0);
+
+    struct timeval start_time;
+    gettimeofday(&start_time, NULL);
+    icmp_msg->originate = (start_time.tv_sec * 1000) + (start_time.tv_usec / 1000);
+    icmp_msg->icmpHdr.checksum = 0;
+    icmp_msg->icmpHdr.checksum = checksum(icmp_msg, sizeof(TimeStamp));
+}
+
+unsigned short checksum(void *b, int len) {
+    unsigned short *buf = b;
+    unsigned int sum = 0;
+
+    for (; len > 1; len -= 2) {
+        sum += *buf++;
+    }
+
+    if (len == 1) {
+        sum += *(unsigned char *)buf;
+    }
+
+    sum = (sum >> 16) + (sum & 0xFFFF);
+    sum += (sum >> 16);
+    return ~sum;
+}
+
+void imprimeError(unsigned char type, unsigned char code) {
+    const char *mensaje = "";
+
+    if (type == 3) {
+        switch (code) {
+            case 0: mensaje = "Net Unreachable"; break;
+            case 1: mensaje = "Host Unreachable"; break;
+            case 2: mensaje = "Protocol Unreachable"; break;
+            case 3: mensaje = "Port Unreachable"; break;
+            case 4: mensaje = "Fragmentation Needed"; break;
+            case 5: mensaje = "Source Route Failed"; break;
+            case 6: mensaje = "Destination Network Unknown"; break;
+            case 7: mensaje = "Destination Host Unknown"; break;
+            case 8: mensaje = "Source Host Isolated"; break;
+            case 11: mensaje = "Destination Network Unreachable for Type of Service"; break;
+            case 12: mensaje = "Destination Host Unreachable for Type of Service"; break;
+            case 13: mensaje = "Communication Administratively Prohibited"; break;
+            case 14: mensaje = "Host Precedence Violation"; break;
+            case 15: mensaje = "Precedence Cutoff in Effect"; break;
+            default: mensaje = "Unknown Code"; break;
+        }
+    } else if (type == 5) {
+        switch (code) {
+            case 1: mensaje = "Redirect for Destination Host"; break;
+            case 3: mensaje = "Redirect for Destination Host Based on Type-of-Service"; break;
+            default: mensaje = "Unknown Code"; break;
+        }
+    } else if (type == 11) {
+        switch (code) {
+            case 0: mensaje = "Time-to-Live Exceeded in Transit"; break;
+            case 1: mensaje = "Fragment Reassembly Time Exceeded"; break;
+            default: mensaje = "Unknown Code"; break;
+        }
+    } else if (type == 12) {
+        switch (code) {
+            case 0: mensaje = "Pointer indicates the error"; break;
+            case 1: mensaje = "Missing a Required Option"; break;
+            case 2: mensaje = "Bad Length"; break;
+            default: mensaje = "Unknown Code"; break;
+        }
+    } else {
+        mensaje = "ICMP Error";
+    }
+
+    printf("-> %s (Type %d, Code %d)\n", mensaje, type, code);
+}