On Oct 4, 2010, at 8:56 AM, Pavel Emelyanov wrote:
> There's the only difference betseen the xs_bind4 and the
> xs_bind6 - the size of sockaddr structure they use.
>
> Fortunately its size can be indirectly get from transport and
> the port in question resides on the same offset within the
> v4 and the v6 sockaddrs.
>
> Signed-off-by: Pavel Emelyanov <xemul@xxxxxxxxxx>
> ---
> net/sunrpc/xprtsock.c | 65 +++++++++++++-----------------------------------
> 1 files changed, 18 insertions(+), 47 deletions(-)
>
> diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
> index 7fdf2bb..3618cfd 100644
> --- a/net/sunrpc/xprtsock.c
> +++ b/net/sunrpc/xprtsock.c
> @@ -1534,23 +1534,19 @@ static unsigned short xs_next_srcport(struct sock_xprt *transport, unsigned shor
> return xprt_max_resvport;
> return --port;
> }
> -
> -static int xs_bind4(struct sock_xprt *transport, struct socket *sock)
> +static int xs_bind(struct sock_xprt *transport, struct socket *sock)
> {
> - struct sockaddr_in myaddr = {
> - .sin_family = AF_INET,
> - };
> - struct sockaddr_in *sa;
> + struct sockaddr myaddr;
You want "struct sockaddr_storage" here. A "struct sockaddr" is required by standard (iirc) to be only as large as a "struct sockaddr_in". So this can't possibly hold an IPv6 socket address without overflowing.
> int err, nloop = 0;
> unsigned short port = xs_get_srcport(transport);
> unsigned short last;
>
> - sa = (struct sockaddr_in *)&transport->srcaddr;
> - myaddr.sin_addr = sa->sin_addr;
> + memcpy(&myaddr, &transport->srcaddr, transport->xprt.addrlen);
> do {
> - myaddr.sin_port = htons(port);
> - err = kernel_bind(sock, (struct sockaddr *) &myaddr,
> - sizeof(myaddr));
> + BUILD_BUG_ON(offsetof(struct sockaddr_in, sin_port) !=
> + offsetof(struct sockaddr_in6, sin6_port));
> + ((struct sockaddr_in *)&myaddr)->sin_port = htons(port);
This series of patches looks mostly OK at first blush, but this little change is a bit offensive. :-)
There should be some static inline helper functions that can get and set the port number in a socket address without a lot of magic, and I would prefer you use those instead. (I would point you directly to them, but I can't easily access kernel source at the moment -- hotel internet sucks).
There should be one or two code examples in the RPC module or in headers that set and get ports in an automatic struct sockaddr_storage variable to give you an idea of what this needs to look like to avoid stack overruns and bad pointer aliasing.
> + err = kernel_bind(sock, &myaddr, transport->xprt.addrlen);
> if (port == 0)
> break;
> if (err == 0) {
> @@ -1562,44 +1558,19 @@ static int xs_bind4(struct sock_xprt *transport, struct socket *sock)
> if (port > last)
> nloop++;
> } while (err == -EADDRINUSE && nloop != 2);
> - dprintk("RPC: %s %pI4:%u: %s (%d)\n",
> - __func__, &myaddr.sin_addr,
> - port, err ? "failed" : "ok", err);
> - return err;
> -}
> -
> -static int xs_bind6(struct sock_xprt *transport, struct socket *sock)
> -{
> - struct sockaddr_in6 myaddr = {
> - .sin6_family = AF_INET6,
> - };
> - struct sockaddr_in6 *sa;
> - int err, nloop = 0;
> - unsigned short port = xs_get_srcport(transport);
> - unsigned short last;
>
> - sa = (struct sockaddr_in6 *)&transport->srcaddr;
> - myaddr.sin6_addr = sa->sin6_addr;
> - do {
> - myaddr.sin6_port = htons(port);
> - err = kernel_bind(sock, (struct sockaddr *) &myaddr,
> - sizeof(myaddr));
> - if (port == 0)
> - break;
> - if (err == 0) {
> - transport->srcport = port;
> - break;
> - }
> - last = port;
> - port = xs_next_srcport(transport, port);
> - if (port > last)
> - nloop++;
> - } while (err == -EADDRINUSE && nloop != 2);
> - dprintk("RPC: xs_bind6 %pI6:%u: %s (%d)\n",
> - &myaddr.sin6_addr, port, err ? "failed" : "ok", err);
> + if (myaddr.sa_family == PF_INET)
> + dprintk("RPC: %s %pI4:%u: %s (%d)\n", __func__,
> + &((struct sockaddr_in *)&myaddr)->sin_addr,
> + port, err ? "failed" : "ok", err);
> + else
> + dprintk("RPC: %s %pI6:%u: %s (%d)\n", __func__,
> + &((struct sockaddr_in6 *)&myaddr)->sin6_addr,
> + port, err ? "failed" : "ok", err);
> return err;
> }
>
> +
> #ifdef CONFIG_DEBUG_LOCK_ALLOC
> static struct lock_class_key xs_key[2];
> static struct lock_class_key xs_slock_key[2];
> @@ -1645,7 +1616,7 @@ static struct socket *xs_create_sock4(struct rpc_xprt *xprt,
> }
> xs_reclassify_socket4(sock);
>
> - if (xs_bind4(transport, sock)) {
> + if (xs_bind(transport, sock)) {
> sock_release(sock);
> goto out;
> }
> @@ -1669,7 +1640,7 @@ static struct socket *xs_create_sock6(struct rpc_xprt *xprt,
> }
> xs_reclassify_socket6(sock);
>
> - if (xs_bind6(transport, sock)) {
> + if (xs_bind(transport, sock)) {
> sock_release(sock);
> goto out;
> }
> --
> 1.5.5.6
>
> --
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--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com
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