Merge branch 'lukas/erts/fix_udp_realloc_bug' into maint

* lukas/erts/fix_udp_realloc_bug:
  erts: Limit the automatic max buffer for UDP to 2^16
  erts: Free udp buffer when getting EAGAIN

1 files changed, 30 insertions, 9 deletions

diff --git a/erts/emulator/drivers/common/inet_drv.c b/erts/emulator/drivers/common/inet_drv.c
index 5e9afdc5ca..2048d0f625 100644
--- a/erts/emulator/drivers/common/inet_drv.c
+++ b/erts/emulator/drivers/common/inet_drv.c
@@ -1549,6 +1549,8 @@ static void *realloc_wrapper(void *current, ErlDrvSizeT size){
 #   define LOAD_ASSOC_ID        LOAD_UINT
 #   define LOAD_ASSOC_ID_CNT    LOAD_UINT_CNT
 #   define SCTP_ANC_BUFF_SIZE   INET_DEF_BUFFER/2 /* XXX: not very good... */
+#else
+#   define IS_SCTP(desc) 0
 #endif
 
 #ifdef HAVE_UDP
@@ -1785,6 +1787,7 @@ static void release_buffer(ErlDrvBinary* buf)
 #ifdef HAVE_UDP
 static ErlDrvBinary* realloc_buffer(ErlDrvBinary* buf, ErlDrvSizeT newsz)
 {
+    DEBUGF(("realloc_buffer: %ld -> %ld\r\n", (buf==NULL) ? 0 : buf->orig_size, newsz));
     return driver_realloc_binary(buf, newsz);
 }
 #endif
@@ -6435,7 +6438,12 @@ static int inet_set_opts(inet_descriptor* desc, char* ptr, int len)
 		(long)desc->port, desc->s, res));
 	if (type == SO_RCVBUF) {
 	    /* make sure we have desc->bufsz >= SO_RCVBUF */
-	    if (ival > desc->bufsz)
+            if (ival > (1 << 16) && desc->stype == SOCK_DGRAM && !IS_SCTP(desc))
+                /* For UDP we don't want to automatically
+                   set the buffer size to be larger than
+                   the theoretical max MTU */
+                desc->bufsz = 1 << 16;
+	    else if (ival > desc->bufsz)
 		desc->bufsz = ival;
 	}
     }
@@ -12042,15 +12050,11 @@ static int packet_inet_input(udp_descriptor* udesc, HANDLE event)
 	sys_memzero((char *) &other, sizeof(other));
 
 	/* udesc->i_buf is only kept between SCTP fragments */
-	if (udesc->i_buf == NULL) {
-	    udesc->i_bufsz = desc->bufsz + len;
-	    if ((udesc->i_buf = alloc_buffer(udesc->i_bufsz)) == NULL)
-		return packet_error(udesc, ENOMEM);
-	    /* pointer to message start */
-	    udesc->i_ptr = udesc->i_buf->orig_bytes + len;
-	} else {
-	    ErlDrvBinary* tmp;
+#ifdef HAVE_SCTP
+	if (udesc->i_buf != NULL) {
+            ErlDrvBinary* tmp;
 	    int bufsz;
+            ASSERT(IS_SCTP(desc));
 	    bufsz = desc->bufsz + (udesc->i_ptr - udesc->i_buf->orig_bytes);
 	    if ((tmp = realloc_buffer(udesc->i_buf, bufsz)) == NULL) {
 		release_buffer(udesc->i_buf);
@@ -12062,6 +12066,15 @@ static int packet_inet_input(udp_descriptor* udesc, HANDLE event)
 		udesc->i_buf = tmp;
 		udesc->i_bufsz = bufsz;
 	    }
+	} else
+#endif
+        {
+            ASSERT(udesc->i_buf == NULL);
+	    udesc->i_bufsz = desc->bufsz + len;
+	    if ((udesc->i_buf = alloc_buffer(udesc->i_bufsz)) == NULL)
+		return packet_error(udesc, ENOMEM);
+	    /* pointer to message start */
+	    udesc->i_ptr = udesc->i_buf->orig_bytes + len;
 	}
 
 	/* Note: On Windows NT, recvfrom() fails if the socket is connected. */
@@ -12120,6 +12133,14 @@ static int packet_inet_input(udp_descriptor* udesc, HANDLE event)
 		) {
 		sock_select(desc,FD_READ,1);
 	    }
+#ifdef HAVE_SCTP
+            if (!short_recv) {
+#endif
+                release_buffer(udesc->i_buf);
+                udesc->i_buf = NULL;
+#ifdef HAVE_SCTP
+            }
+#endif
 	    return count;		/* strange, not ready */
 	}