add: implement ttl

src/main.c

@@ -31,7 +31,7 @@
 
 bool loop = true;
 
-void signal_handler(int code)
+static void signal_handler(int code)
 {
     (void) code;
     loop = false;
@@ -76,7 +76,6 @@ static int get_setting(char * const *av, struct setting *setting)
         {NULL, "v", OPTION, false},
         {NULL, "f", OPTION, false},
         {NULL, "n", OPTION, false},
-        {NULL, "W",ARGUMENT, "0"},
         {"ttl", NULL, ARGUMENT, "116"},
         {NULL, "s", ARGUMENT, "56"},
         {NULL, NULL, 0, NULL},
@@ -90,15 +89,57 @@ static int get_setting(char * const *av, struct setting *setting)
     setting->verbose = parameters[1].value;
     setting->flood = parameters[2].value;
     setting->numeric_only = parameters[3].value;
-    if (parsing_number(parameters[4].value, 0, 2147483647, &setting->timeout))
-        return 1;
-    if (parsing_number(parameters[5].value, 0, 255, &setting->ttl))
+    size_t ttl;
+    if (parsing_number(parameters[4].value, 0, 255, &ttl))
         return 2;
-    if (parsing_number(parameters[6].value, 0, 2147483647, &setting->payload_size))
+    if (parsing_number(parameters[5].value, 0, 2147483647, &setting->payload_size))
         return 3;
+    setting->ttl = ttl;
     return  0;
 }
 
+static int create_socket(struct setting const *setting)
+{
+    int ret;
+
+    int sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
+
+    if (sockfd == -1)
+    {
+        print_err("open socket failed, maybe try in root (:");
+        return -1;
+    }
+
+    ret = setsockopt(sockfd, IPPROTO_IP, IP_TTL, &setting->ttl, sizeof(uint8_t));
+    if (ret != 0)
+    {
+        print_err("Failed to setsockopt(): ttl");
+        return -1;
+    }
+
+    struct timeval tv = {1, 0};
+    ret = setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
+    if (ret != 0)
+    {
+        print_err("Failed to setsockopt(): recv timeout");
+        return -1;
+    }
+
+    return sockfd;
+}
+
+static int set_destination(struct hostenv *host)
+{
+    if (dns_lookup(host))
+        return 1;
+    
+    host->ip.sin_family = AF_INET;
+    host->ip.sin_port = htons(0);       
+    inet_pton(AF_INET, host->ipstr, &host->ip.sin_addr);
+
+    return 0;
+}
+
 int main(int ac, char **av)
 {
     (void) ac;
@@ -112,22 +153,12 @@ int main(int ac, char **av)
 
     signal(SIGINT, signal_handler);
 
-    if (dns_lookup(&settings.dest))
-        return 5;
-    
-    settings.dest.ip.sin_family = AF_INET;
-    settings.dest.ip.sin_port = htons(0);       
-    inet_pton(AF_INET, settings.dest.ipstr, &settings.dest.ip.sin_addr);
-
-    dns_reverse_lookup(&settings.dest);
-
-    int sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
-
-    if (sockfd == -1)
-    {
-        print_err("open socket failed, maybe try in root (:");
+    if (set_destination(&settings.dest))
+        return 1;
+
+    int sockfd = create_socket(&settings);
+    if (sockfd == -1)
         return 1;
-    }
 
     char *packet = packet_create(settings.payload_size);
     if (packet == NULL)
@@ -166,9 +197,12 @@ int main(int ac, char **av)
 
         stats.packets_sent++;
 
+        int ret = 0;
         do
         {
-            if (recvfrom(sockfd, buffer, packet_size, 0, (struct sockaddr *) &sender, &len) < 0)
+            buffer[0] = 0;
+            ret = recvfrom(sockfd, buffer, packet_size, 0, (struct sockaddr *) &sender, &len) < 0;
+            if (ret == -1)
             {
                 print_err("error: receive packet failed.");
                 close(sockfd);
@@ -178,13 +212,13 @@ int main(int ac, char **av)
             }
             gettimeofday(&stop, NULL);
         }
-        while (len == packet_size && packet_check(buffer, packet_size) == 0 && packet_compare(packet, buffer, packet_size) == 0);
+        while (!(ret == 1 && buffer[0] == '\0') || (len == packet_size && packet_check(buffer, packet_size) == 0 && packet_compare(packet, buffer, packet_size) == 0));
 
-        stats.packets_received++;
-
-        struct icmphdr *hdr = (struct icmphdr *) packet;
-
-        print_ping(&settings, hdr, &start, &stop);
+        if (*buffer != 0)
+        {
+            stats.packets_received++;
+            print_recv(&settings, (struct icmphdr *)buffer, &start, &stop);
+        }
         
         sleep(1);
 

src/print.c

@@ -52,7 +52,7 @@ void print_statistics(struct statistics const *stats, struct setting const *sett
 void print_recv(const struct setting *settings, const struct icmphdr *header, const struct timeval *start, const struct timeval *stop)
 {
 
-    printf("%zu bytes from %s: icmp_seq=%d ttl=%zu time=%.3f ms\n",
+    printf("%zu bytes from %s: icmp_seq=%d ttl=%d time=%.3f ms\n",
         settings->payload_size + sizeof(struct icmphdr),
         settings->dest.ipstr,
         htons(header->un.echo.sequence),

src/setting.h

@@ -2,6 +2,7 @@
 
 #include "host.h"
 
+#include <stdint.h>
 #include <stddef.h>
 #include <stdbool.h>
 
@@ -12,7 +13,7 @@ struct setting
     bool flood;
     bool numeric_only;
     size_t timeout;
-    size_t ttl;
+    uint8_t ttl;
     size_t payload_size;
     struct hostenv dest;
 };