[PATCH v3 0/1] MR3367: server: Ignore EADDRINUSE from listen() unless the provided socket is wildcarded.

[Ally Sommers (＠dropbear)]

This fixes a `todo_wine` in ws2_32's socket tests.

--
  v3: server: Ignore EADDRINUSE from listen() unless the provided socket is wildcarded.

https://gitlab.winehq.org/wine/wine/-/merge_requests/3367

[PATCH v3 1/1] server: Ignore EADDRINUSE from listen() unless the provided socket is wildcarded.

[Ally Sommers]

From: Ally Sommers

---
 dlls/ws2_32/tests/sock.c |  2 +-
 server/sock.c            | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/dlls/ws2_32/tests/sock.c b/dlls/ws2_32/tests/sock.c
index e6ab5065cfe..4bf705ecf96 100644
--- a/dlls/ws2_32/tests/sock.c
+++ b/dlls/ws2_32/tests/sock.c
@@ -2241,7 +2241,7 @@ static void test_reuseaddr(void)
         rc = listen(s1, 1);
         ok(!rc, "got error %d.\n", WSAGetLastError());
         rc = listen(s2, 1);
-        todo_wine ok(!rc, "got error %d.\n", WSAGetLastError());
+        ok(!rc, "got error %d.\n", WSAGetLastError());
         rc = connect(s3, tests[i].addr_loopback, tests[i].addrlen);
         ok(!rc, "got error %d.\n", WSAGetLastError());

diff --git a/server/sock.c b/server/sock.c
index 2aae9aefbf0..bb70ce3703a 100644
--- a/server/sock.c
+++ b/server/sock.c
@@ -2525,6 +2525,21 @@ static void sock_ioctl( struct fd *fd, ioctl_code_t code, struct async *async )

if (listen( unix_fd, params->backlog ) < 0)
         {
+            if (errno == EADDRINUSE)
+                switch (sock->family)
+                {
+                    case WS_AF_INET:
+                        if (sock->addr.in.sin_addr.S_un.S_addr != htonl( INADDR_ANY ))
+                            return;
+                    case WS_AF_INET6:
+                    {
+                        union unix_sockaddr unix_addr;
+                        socklen_t len = sockaddr_to_unix(&sock->addr.addr, sizeof(struct WS_sockaddr_in6), &unix_addr);
+                        if (len && !IN6_IS_ADDR_UNSPECIFIED(&unix_addr.in6.sin6_addr))
+                            return;
+                    }
+                }
+
             set_error( sock_get_ntstatus( errno ) );
             return;
         }

[PATCH v3 1/1] server: Ignore EADDRINUSE from listen() unless the provided socket is wildcarded.

[Paul Gofman]

What is the purpose if this patch, does it fix any real application? The meaning of that test is that with SO_REUSADDR on Windows multiple sockets can be bound to the same address, and a newly bound socket may actually receive connection on it, either at once or when the other socket will be closed. Maybe it is possible to achieve with Linux SO_REUSEPORT and BPF filters, but probably not by ignoring an error on listen.
> On 21 Jul 2023, at 0:23, Ally Sommers  wrote:
>
> From: Ally Sommers
>
> dlls/ws2_32/tests/sock.c |  2 +-
> server/sock.c            | 15 +++++++++++++++
> 2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/dlls/ws2_32/tests/sock.c b/dlls/ws2_32/tests/sock.c
> index e6ab5065cfe..4bf705ecf96 100644
> --- a/dlls/ws2_32/tests/sock.c
> +++ b/dlls/ws2_32/tests/sock.c
> @@ -2241,7 +2241,7 @@ static void test_reuseaddr(void)
>         rc = listen(s1, 1);
>         ok(!rc, "got error %d.\n", WSAGetLastError());
>         rc = listen(s2, 1);
> -
>    todo_wine ok(!rc, "got error %d.\n", WSAGetLastError());
> -
>    ok(!rc, "got error %d.\n", WSAGetLastError());
>   rc = connect(s3, tests[i].addr_loopback, tests[i].addrlen);
>   ok(!rc, "got error %d.\n", WSAGetLastError());
>
> diff --git a/server/sock.c b/server/sock.c
> index 2aae9aefbf0..bb70ce3703a 100644
> --- a/server/sock.c
> +++ b/server/sock.c
> @@ -2525,6 +2525,21 @@ static void sock_ioctl( struct fd *fd, ioctl_code_t code, struct async *async )
>     if (listen( unix_fd, params->backlog ) < 0)
>     {
> -
>        if (errno == EADDRINUSE)
> -
>            switch (sock->family)
> -
>            {
> -
>                case WS_AF_INET:
> -
>                    if (sock->addr.in.sin_addr.S_un.S_addr != htonl( INADDR_ANY ))
> -
>                        return;
> -
>                case WS_AF_INET6:
> -
>                {
> -
>                    union unix_sockaddr unix_addr;
> -
>                    socklen_t len = sockaddr_to_unix(&sock->addr.addr, sizeof(struct WS_sockaddr_in6), &unix_addr);
> -
>                    if (len && !IN6_IS_ADDR_UNSPECIFIED(&unix_addr.in6.sin6_addr))
> -
>                        return;
> -
>                }
> -
>            }
> -
>       set_error( sock_get_ntstatus( errno ) );
>       return;
>   }
>
> -- 
> GitLab
>
> https://gitlab.winehq.org/wine/wine/-/merge_requests/3367