On Thu, 26 Aug 2010 10:34:56 -0700
Ben Greear <greearb@xxxxxxxxxxxxxxx> wrote:
> When using multi-homed machines, it's nice to be able to specify
> the local IP to use for outbound connections. This patch gives
> cifs the ability to bind to a particular IP address.
>
> Usage: mount -t cifs -o bindaddr=192.168.1.50,user=foo, ...
>
> Signed-off-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
> ---
> :100644 100644 b7431af... 77293db... M fs/cifs/cifsfs.c
> :100644 100644 c9d0cfc... c0176d8... M fs/cifs/cifsglob.h
> :100644 100644 ec0ea4a... bacbf46... M fs/cifs/connect.c
> fs/cifs/cifsfs.c | 4 +++
> fs/cifs/cifsglob.h | 1 +
> fs/cifs/connect.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++-
> 3 files changed, 56 insertions(+), 2 deletions(-)
>
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index b7431af..77293db 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -374,6 +374,10 @@ cifs_show_options(struct seq_file *s, struct vfsmount *m)
> if (tcon->ses->domainName)
> seq_printf(s, ",domain=%s", tcon->ses->domainName);
>
> + if (tcon->ses->server->ip4_local_ip)
> + seq_printf(s, ",bindaddr=%pI4",
> + &tcon->ses->server->ip4_local_ip);
> +
> seq_printf(s, ",uid=%d", cifs_sb->mnt_uid);
> if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_UID)
> seq_printf(s, ",forceuid");
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index c9d0cfc..c0176d8 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -157,6 +157,7 @@ struct TCP_Server_Info {
> struct sockaddr_in sockAddr;
> struct sockaddr_in6 sockAddr6;
> } addr;
> + u32 ip4_local_ip;
> wait_queue_head_t response_q;
> wait_queue_head_t request_q; /* if more than maxmpx to srvr must block*/
> struct list_head pending_mid_q;
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index ec0ea4a..bacbf46 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -105,6 +105,7 @@ struct smb_vol {
> bool sockopt_tcp_nodelay:1;
> unsigned short int port;
> char *prepath;
> + u32 local_ip; /* allow binding to a local IP address if != 0 */
> struct nls_table *local_nls;
> };
>
> @@ -1064,6 +1065,32 @@ cifs_parse_mount_options(char *options, const char *devname,
> "long\n");
> return 1;
> }
> + } else if (strnicmp(data, "bindaddr", 8) == 0) {
> + struct sockaddr_storage laddr;
> + memset(&laddr, 0, sizeof(laddr));
> +
> + if (!value || !*value) {
> + printk(KERN_WARNING "CIFS: bindaddr value"
> + " not specified.\n");
> + return 1; /* needs_arg; */
> + }
> + i = cifs_convert_address((struct sockaddr *)(&laddr),
> + value, strlen(value));
> + if (i < 0) {
> + vol->local_ip = 0;
> + printk(KERN_WARNING "CIFS: Could not parse"
> + " bindaddr: %s\n",
> + value);
> + return 1;
> + } else {
> + struct sockaddr_in *s4;
> + s4 = (struct sockaddr_in *)&laddr;
> + if (s4->sin_family == AF_INET)
> + vol->local_ip = s4->sin_addr.s_addr;
> + else
> + printk(KERN_WARNING "WARNING: IPv6 "
> + "bindaddr not supported yet.\n");
> + }
> } else if (strnicmp(data, "prefixpath", 10) == 0) {
> if (!value || !*value) {
> printk(KERN_WARNING
> @@ -1393,7 +1420,8 @@ cifs_parse_mount_options(char *options, const char *devname,
> }
>
> static bool
> -match_address(struct TCP_Server_Info *server, struct sockaddr *addr)
> +match_address(struct TCP_Server_Info *server, struct sockaddr *addr,
> + u32 local_ip4)
> {
> struct sockaddr_in *addr4 = (struct sockaddr_in *)addr;
> struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)addr;
> @@ -1406,6 +1434,8 @@ match_address(struct TCP_Server_Info *server, struct sockaddr *addr)
> if (addr4->sin_port &&
> addr4->sin_port != server->addr.sockAddr.sin_port)
> return false;
> + if (local_ip4 && (local_ip4 != server->ip4_local_ip))
> + return false;
> break;
> case AF_INET6:
> if (!ipv6_addr_equal(&addr6->sin6_addr,
> @@ -1487,7 +1517,7 @@ cifs_find_tcp_session(struct sockaddr *addr, struct smb_vol *vol)
> if (server->tcpStatus == CifsNew)
> continue;
>
> - if (!match_address(server, addr))
> + if (!match_address(server, addr, vol->local_ip))
> continue;
>
> if (!match_security(server, vol))
> @@ -1602,6 +1632,7 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
> * no need to spinlock this init of tcpStatus or srv_count
> */
> tcp_ses->tcpStatus = CifsNew;
> + tcp_ses->ip4_local_ip = volume_info->local_ip;
> ++tcp_ses->srv_count;
>
> if (addr.ss_family == AF_INET6) {
> @@ -1678,6 +1709,10 @@ cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb_vol *vol)
> vol->password ? vol->password : "",
> MAX_PASSWORD_SIZE))
> continue;
> + if (server->ip4_local_ip &&
> + (server->ip4_local_ip != ses->server->ip4_local_ip))
> + continue;
> + /* TODO: Deal with IPv6 local addr matching? --Ben */
> }
> ++ses->ses_count;
> write_unlock(&cifs_tcp_ses_lock);
> @@ -2051,6 +2086,20 @@ ipv4_connect(struct TCP_Server_Info *server)
> cifs_reclassify_socket4(socket);
> }
>
> + /* Bind to the local IP address if specified */
> + if (server->ip4_local_ip) {
> + struct sockaddr_in myaddr = {
> + .sin_family = AF_INET,
> + };
> + myaddr.sin_addr.s_addr = server->ip4_local_ip;
> + myaddr.sin_port = 0; /* any */
> + rc = socket->ops->bind(socket, (struct sockaddr *) &myaddr,
> + sizeof(myaddr));
> + if (rc < 0)
> + cERROR(1, "Failed to bind to: %pI4, error: %d\n",
> + &server->ip4_local_ip, rc);
> + }
> +
> /* user overrode default port */
> if (server->addr.sockAddr.sin_port) {
> rc = socket->ops->connect(socket, (struct sockaddr *)
I'm not crazy about this patch. It seems like this ought to be the
purview of the routing table. I know however that there are situations
where that's not really possible (clusters with floating IP addrs, for
instance).
That said, even if we were to do something along these lines, it seems
like it ought to be more transport neutral (i.e. not IPv4 only like
this patch is).
--
Jeff Layton <jlayton@xxxxxxxxx>
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