Fix running on servers with disabled IPv6, fixes #118

CHANGELOG.md

@@ -4,6 +4,7 @@ fping 4.1 (UNRELEASED)
 ## Bugfixes and other changes
 
 - Fix problem when socket fd is 0 (#125, thanks Ramón Novoa!)
+- Fix running on servers with disabled IPv6 (#118, thanks Simon Matter)
 
 fping 4.0 (2017-04-23)
 ======================

ci/test-11-nopriv.pl

@@ -18,5 +18,5 @@ system("cp $fping_bin /tmp/fping.copy; chmod +x /tmp/fping.copy");
 my $cmd = Test::Command->new(cmd => "/tmp/fping.copy 127.0.0.1");
 $cmd->exit_is_num(4);
 $cmd->stdout_is_eq("");
-$cmd->stderr_like(qr{: can't create socket \(must run as root\?\) : .*\n});
+$cmd->stderr_like(qr{: can't create socket \(must run as root\?\)});
 }

src/fping.c

@@ -231,11 +231,11 @@ HOST_ENTRY* ev_last;
 
 char* prog;
 int ident; /* our pid */
-int socket4 = 0;
+int socket4 = -1;
 #ifndef IPV6
 int hints_ai_family = AF_INET;
 #else
-int socket6 = 0;
+int socket6 = -1;
 int hints_ai_family = AF_UNSPEC;
 #endif
 
@@ -435,14 +435,14 @@ int main(int argc, char** argv)
             break;
         case 'M':
 #ifdef IP_MTU_DISCOVER
-            if (socket4) {
+            if (socket4 >= 0) {
                 int val = IP_PMTUDISC_DO;
                 if (setsockopt(socket4, IPPROTO_IP, IP_MTU_DISCOVER, &val, sizeof(val))) {
                     perror("setsockopt IP_MTU_DISCOVER");
                 }
             }
 #ifdef IPV6
-            if (socket6) {
+            if (socket6 >= 0) {
                 int val = IPV6_PMTUDISC_DO;
                 if (setsockopt(socket6, IPPROTO_IPV6, IPV6_MTU_DISCOVER, &val, sizeof(val))) {
                     perror("setsockopt IPV6_MTU_DISCOVER");
@@ -624,13 +624,13 @@ int main(int argc, char** argv)
 
         case 'I':
 #ifdef SO_BINDTODEVICE
-            if (socket4) {
+            if (socket4 >= 0) {
                 if (setsockopt(socket4, SOL_SOCKET, SO_BINDTODEVICE, optparse_state.optarg, strlen(optparse_state.optarg))) {
                     perror("binding to specific interface (SO_BINTODEVICE)");
                 }
             }
 #ifdef IPV6
-            if (socket6) {
+            if (socket6 >= 0) {
                 if (setsockopt(socket6, SOL_SOCKET, SO_BINDTODEVICE, optparse_state.optarg, strlen(optparse_state.optarg))) {
                     perror("binding to specific interface (SO_BINTODEVICE), IPV6");
                 }
@@ -649,13 +649,13 @@ int main(int argc, char** argv)
 
         case 'O':
             if (sscanf(optparse_state.optarg, "%i", &tos)) {
-                if (socket4) {
+                if (socket4 >= 0) {
                     if (setsockopt(socket4, IPPROTO_IP, IP_TOS, &tos, sizeof(tos))) {
                         perror("setting type of service octet IP_TOS");
                     }
                 }
 #if defined(IPV6) && defined(IPV6_TCLASS)
-                if (socket6) {
+                if (socket6 >= 0) {
                     if (setsockopt(socket6, IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos))) {
                         perror("setting type of service octet IPV6_TCLASS");
                     }
@@ -681,6 +681,10 @@ int main(int argc, char** argv)
 
     /* validate various option settings */
 
+    if (socket4 < 0 && socket6 < 0) {
+        crash_and_burn("can't create socket (must run as root?)");
+    }
+
     if (ttl > 255) {
         fprintf(stderr, "%s: ttl %u out of range\n", prog, ttl);
         exit(1);
@@ -827,13 +831,13 @@ int main(int argc, char** argv)
 
     /* set the TTL, if the -H option was set (otherwise ttl will be = 0) */
     if (ttl > 0) {
-        if (socket4) {
+        if (socket4 >= 0) {
             if (setsockopt(socket4, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl))) {
                 perror("setting time to live");
             }
         }
 #ifdef IPV6
-        if (socket6) {
+        if (socket6 >= 0) {
             if (setsockopt(socket6, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl))) {
                 perror("setting time to live");
             }
@@ -844,13 +848,13 @@ int main(int argc, char** argv)
 #if HAVE_SO_TIMESTAMP
     {
         int opt = 1;
-        if (socket4) {
+        if (socket4 >= 0) {
             if (setsockopt(socket4, SOL_SOCKET, SO_TIMESTAMP, &opt, sizeof(opt))) {
                 perror("setting SO_TIMESTAMP option");
             }
         }
 #ifdef IPV6
-        if (socket6) {
+        if (socket6 >= 0) {
             if (setsockopt(socket6, SOL_SOCKET, SO_TIMESTAMP, &opt, sizeof(opt))) {
                 perror("setting SO_TIMESTAMP option (IPv6)");
             }

src/socket4.c

@@ -62,7 +62,7 @@ int open_ping_socket_ipv4()
         /* try non-privileged icmp (works on Mac OSX without privileges, for example) */
         s = socket(AF_INET, SOCK_DGRAM, proto->p_proto);
         if (s < 0) {
-            errno_crash_and_burn("can't create socket (must run as root?)");
+            return -1;
         }
     }
 

src/socket6.c

@@ -61,7 +61,7 @@ int open_ping_socket_ipv6()
         /* try non-privileged icmp (works on Mac OSX without privileges, for example) */
         s = socket(AF_INET6, SOCK_DGRAM, proto->p_proto);
         if (s < 0) {
-            errno_crash_and_burn("can't create raw socket (must run as root?)");
+            return -1;
         }
     }