Add patch from Per Hedeland

 Per H @ Tail-f: The original code here had problems that possibly
   only occur if you abuse it for non-INET sockets, but anyway:
   a) If the getsockopt for SO_PRIORITY or IP_TOS failed, the actual
      requested setsockopt was never even attempted.
   b) If {get,set}sockopt for one of IP_TOS and SO_PRIORITY failed,
      but ditto for the other worked and that was actually the requested
      option, failure was still reported to erlang.

1 files changed, 28 insertions, 14 deletions

diff --git a/erts/emulator/drivers/common/inet_drv.c b/erts/emulator/drivers/common/inet_drv.c
index 49da0ef118..b491242aea 100644
--- a/erts/emulator/drivers/common/inet_drv.c
+++ b/erts/emulator/drivers/common/inet_drv.c
@@ -5050,9 +5050,17 @@ static STATUS wrap_sockopt(STATUS (*function)() /* Yep, no parameter
 }
 #endif
 
+/* Per H @ Tail-f: The original code here had problems that possibly
+   only occur if you abuse it for non-INET sockets, but anyway:
+   a) If the getsockopt for SO_PRIORITY or IP_TOS failed, the actual
+      requested setsockopt was never even attempted.
+   b) If {get,set}sockopt for one of IP_TOS and SO_PRIORITY failed,
+      but ditto for the other worked and that was actually the requested
+      option, failure was still reported to erlang.                  */
+
 #if  defined(IP_TOS) && defined(SOL_IP) && defined(SO_PRIORITY)
 static int setopt_prio_tos_trick
-	   (int fd, int proto, int type, char* arg_ptr, int arg_sz)
+	(int fd, int proto, int type, char* arg_ptr, int arg_sz, int propagate)
 {
     /* The relations between SO_PRIORITY, TOS and other options
        is not what you (or at least I) would expect...:
@@ -5065,6 +5073,8 @@ static int setopt_prio_tos_trick
     int          tmp_ival_prio;
     int          tmp_ival_tos;
     int          res;
+    int          res_prio;
+    int          res_tos;
 #ifdef HAVE_SOCKLEN_T
 	    socklen_t
 #else
@@ -5073,31 +5083,35 @@ static int setopt_prio_tos_trick
 		tmp_arg_sz_prio = sizeof(tmp_ival_prio),
 		tmp_arg_sz_tos  = sizeof(tmp_ival_tos);
 
-    res = sock_getopt(fd, SOL_SOCKET, SO_PRIORITY,
+    res_prio = sock_getopt(fd, SOL_SOCKET, SO_PRIORITY,
 		      (char *) &tmp_ival_prio, &tmp_arg_sz_prio);
-    if (res == 0) {
-	res = sock_getopt(fd, SOL_IP, IP_TOS, 
+    res_tos = sock_getopt(fd, SOL_IP, IP_TOS, 
 		      (char *) &tmp_ival_tos, &tmp_arg_sz_tos);
-	if (res == 0) {
 	    res = sock_setopt(fd, proto, type, arg_ptr, arg_sz);
 	    if (res == 0) {
 		if (type != SO_PRIORITY) {
-		    if (type != IP_TOS) {
-			res = sock_setopt(fd, 
+	    if (type != IP_TOS && res_tos == 0) {
+		res_tos = sock_setopt(fd, 
 					  SOL_IP, 
 					  IP_TOS,
 					  (char *) &tmp_ival_tos, 
 					  tmp_arg_sz_tos);
+		if (propagate)
+		    res = res_tos;
 		    }
-		    if (res == 0) {
-			res =  sock_setopt(fd, 
+	    if (res == 0 && res_prio == 0) {
+		res_prio = sock_setopt(fd, 
 					   SOL_SOCKET, 
 					   SO_PRIORITY,
 					   (char *) &tmp_ival_prio, 
 					   tmp_arg_sz_prio);
-			if (res != 0 && sock_errno() == EPERM) {
-			    res = 0;
-			}
+		if (propagate) {		
+		    /* Some kernels set a SO_PRIORITY by default that you are not permitted to reset,
+		       silently ignore this error condition */
+		    if (res_prio != 0 && sock_errno() == EPERM) {
+			res = 0;
+		    } else {
+			res = res_prio;
 		    }
 		}
 	    }
@@ -5443,7 +5457,7 @@ static int inet_set_opts(inet_descriptor* desc, char* ptr, int len)
 	    return -1;
 	}
 #if  defined(IP_TOS) && defined(SOL_IP) && defined(SO_PRIORITY)
-	res = setopt_prio_tos_trick (desc->s, proto, type, arg_ptr, arg_sz);
+	res = setopt_prio_tos_trick (desc->s, proto, type, arg_ptr, arg_sz, propagate);
 #else
 	res = sock_setopt	    (desc->s, proto, type, arg_ptr, arg_sz);
 #endif
@@ -5973,7 +5987,7 @@ static int sctp_set_opts(inet_descriptor* desc, char* ptr, int len)
 	    return -1;
 	}
 #if  defined(IP_TOS) && defined(SOL_IP) && defined(SO_PRIORITY)
-	res = setopt_prio_tos_trick (desc->s, proto, type, arg_ptr, arg_sz);
+	res = setopt_prio_tos_trick (desc->s, proto, type, arg_ptr, arg_sz, 1);
 #else
 	res = sock_setopt	    (desc->s, proto, type, arg_ptr, arg_sz);
 #endif