[Spice-devel] [PATCH spice-server v4 08/20] sys-socket: Add socket_newpair utility

[Marc-André Lureau]

Hi

On Wed, Feb 6, 2019 at 2:59 PM Frediano Ziglio <fziglio at redhat.com> wrote:
>
> Allows to easier port socketpair.
> Windows does not have this function, we need to create a pair
> using 2 internet sockets and connecting one to the other.
>
> Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
> ---
>  server/sys-socket.c | 75 +++++++++++++++++++++++++++++++++++++++++++++
>  server/sys-socket.h |  3 ++
>  2 files changed, 78 insertions(+)
>
> diff --git a/server/sys-socket.c b/server/sys-socket.c
> index 7ce5dab1..837da18e 100644
> --- a/server/sys-socket.c
> +++ b/server/sys-socket.c
> @@ -209,4 +209,79 @@ SPICE_CONSTRUCTOR_FUNC(socket_win32_init)
>      WSADATA wsaData;
>      WSAStartup(MAKEWORD(2, 2), &wsaData);
>  }
> +
> +int socket_newpair(int type, int protocol, int sv[2])

overall, looks good.

Since it's limited to inet protocols, why not remove "protocol"
argument, and call it socket_new_inet_pair() ?

If you are using this for worker thread communication, a windows pipe
would be a better fit. (and GIO provides stream abstraction, wing has
a namedpipe implementation - based on the one we used to have in
spice-gtk for controller communication)

> +{
> +    struct sockaddr_in sa, sa2;
> +    socklen_t addrlen;
> +    SOCKET s, pairs[2];
> +
> +    if (!sv) {
> +        return -1;
> +    }
> +
> +    /* create a listener */
> +    s = socket(AF_INET, type, 0);
> +    if (s == INVALID_SOCKET) {
> +        return -1;
> +    }
> +
> +    pairs[1] = INVALID_SOCKET;
> +
> +    pairs[0] = socket(AF_INET, type, 0);
> +    if (pairs[0] == INVALID_SOCKET) {
> +        goto cleanup;
> +    }
> +
> +    /* bind to a random port */
> +    sa.sin_family = AF_INET;
> +    sa.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
> +    sa.sin_port = 0;
> +    if (bind(s, (struct sockaddr*) &sa, sizeof(sa)) < 0) {
> +        goto cleanup;
> +    }
> +    if (listen(s, 1) < 0) {
> +        goto cleanup;
> +    }
> +
> +    /* connect to kernel choosen port */
> +    addrlen = sizeof(sa);
> +    if (getsockname(s, (struct sockaddr*) &sa, &addrlen) < 0) {
> +        goto cleanup;
> +    }
> +    if (connect(pairs[0], (struct sockaddr*) &sa, sizeof(sa)) < 0) {
> +        goto cleanup;
> +    }
> +    addrlen = sizeof(sa2);
> +    pairs[1] = accept(s, (struct sockaddr*) &sa2, &addrlen);
> +    if (pairs[1] == INVALID_SOCKET) {
> +        goto cleanup;
> +    }
> +
> +    /* check proper connection */
> +    addrlen = sizeof(sa);
> +    if (getsockname(pairs[0], (struct sockaddr*) &sa, &addrlen) < 0) {
> +        goto cleanup;
> +    }
> +    addrlen = sizeof(sa2);
> +    if (getpeername(pairs[1], (struct sockaddr*) &sa2, &addrlen) < 0) {
> +        goto cleanup;
> +    }
> +    if (sa.sin_family != sa2.sin_family || sa.sin_port != sa2.sin_port
> +        || sa.sin_addr.s_addr != sa2.sin_addr.s_addr) {
> +        goto cleanup;
> +    }
> +
> +    closesocket(s);
> +    sv[0] = pairs[0];
> +    sv[1] = pairs[1];
> +    return 0;
> +
> +cleanup:
> +    socket_win32_set_errno();
> +    closesocket(s);
> +    closesocket(pairs[0]);
> +    closesocket(pairs[1]);
> +    return -1;
> +}
>  #endif
> diff --git a/server/sys-socket.h b/server/sys-socket.h
> index 65062571..3a3b7878 100644
> --- a/server/sys-socket.h
> +++ b/server/sys-socket.h
> @@ -134,6 +134,9 @@ socket_accept(int sock, struct sockaddr *addr, int *addrlen)
>  }
>  #undef accept
>  #define accept socket_accept
> +
> +int socket_newpair(int type, int protocol, int sv[2]);
> +#define socketpair(family, type, protocol, sv) socket_newpair(type, protocol, sv)
>  #endif
>
>  #endif // RED_SYS_SOCKET_H_
> --
> 2.20.1
>
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-- 
Marc-André Lureau