[PATCH v6 2/2] ntdll: Do not send data to port 0.

[Jason Beetham]

From: Jason Beetham

---
On Windows it seems sending to port 0 does nothing and does not error.
Presently sendmsg errors with EINVAL.
This works around it, by checking if it's port 0 then skipping the data.
---
 dlls/ntdll/unix/socket.c | 56 ++++++++++++++++++++++++++++++++++++++--
 dlls/ws2_32/tests/sock.c |  4 +--
 2 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/dlls/ntdll/unix/socket.c b/dlls/ntdll/unix/socket.c
index ac351a17a70..d3af99be693 100644
--- a/dlls/ntdll/unix/socket.c
+++ b/dlls/ntdll/unix/socket.c
@@ -979,6 +979,41 @@ NTSTATUS sock_read( HANDLE handle, int fd, HANDLE event, PIO_APC_ROUTINE apc,
     return sock_recv( handle, event, apc, apc_user, io, fd, async, 1 );
 }

+static int is_port0( const union unix_sockaddr *uaddr)
+{
+    switch (uaddr->addr.sa_family)
+    {
+        case AF_INET:
+        {
+            return uaddr->in.sin_port == 0;
+        }
+
+        case AF_INET6:
+        {
+            return uaddr->in6.sin6_port == 0;
+        }
+
+    #ifdef HAS_IPX
+        case AF_IPX:
+        {
+            return uaddr->ipx.sipx_port == 0;
+        }
+    #endif
+
+    #ifdef HAS_IRDA
+        case AF_IRDA:
+        {
+            return FALSE;
+        }
+    #endif
+
+        case AF_UNSPEC:
+            return FALSE;
+
+        default:
+            return FALSE;
+        }
+}

static NTSTATUS try_send( int fd, struct async_send_ioctl *async )
 {
@@ -1018,6 +1053,7 @@ static NTSTATUS try_send( int fd, struct async_send_ioctl *async )
     hdr.msg_iov = async->iov + async->iov_cursor;
     hdr.msg_iovlen = async->count - async->iov_cursor;

+
     while ((ret = sendmsg( fd, &hdr, async->unix_flags )) == -1)
     {
         if (errno == EISCONN)
@@ -1027,8 +1063,24 @@ static NTSTATUS try_send( int fd, struct async_send_ioctl *async )
         }
         else if (errno != EINTR)
         {
-            if (errno != EWOULDBLOCK) WARN( "sendmsg: %s\n", strerror( errno ) );
-            return sock_errno_to_status( errno );
+            if(errno == EINVAL && is_port0(&unix_addr)){
+
+                /*
+                * Some Windows applications(Spellforce 3 is known to) send to port 0.
+                * This causes 'sendmsg' to throw a EINVAL error on Windows this does nothing but consume the data.
+                * This workaround says we successfully sent data even though we didnt send anything.
+                * Matching the Windows behaviour, making the program work(in theory).
+                */
+                ret = 0;
+                for(ssize_t i = 0; i < hdr.msg_iovlen; i++){
+                    ret += hdr.msg_iov[i].iov_len;
+                }
+                WARN("Attempting to send to port 0, skipping over %zd bytes\n", ret);
+                break;
+            }else{
+              if (errno != EWOULDBLOCK) WARN( "sendmsg: %s\n", strerror( errno ) );
+              return sock_errno_to_status( errno );
+            }
         }
     }

diff --git a/dlls/ws2_32/tests/sock.c b/dlls/ws2_32/tests/sock.c
index ae8bb15f074..ec790a9b1c1 100644
--- a/dlls/ws2_32/tests/sock.c
+++ b/dlls/ws2_32/tests/sock.c
@@ -13678,8 +13678,8 @@ static void test_WSASendto_port0(void)
     ok(s != INVALID_SOCKET, "failed to create socket, error %u\n", WSAGetLastError());

ret = WSASendTo(s, &data_buf, 1, &bytesSent, 0, (struct sockaddr *)&addr, sizeof(addr), NULL, NULL);
-    todo_wine ok(!ret, "got error %u\n", WSAGetLastError());
-    todo_wine ok(bytesSent == sizeof(buf), "Failed to send full data(%lu) only sent(%lu)\n", (unsigned long) sizeof(buf), (unsigned long) bytesSent);
+    ok(!ret, "got error %u\n", WSAGetLastError());
+    ok(bytesSent == sizeof(buf), "Failed to send full data(%lu) only sent(%lu)\n", (unsigned long) sizeof(buf), (unsigned long) bytesSent);
     closesocket(s);
 }