Re: [cifs bindaddr v5] cifs: Allow binding to local IP address.

Re: [cifs bindaddr v5] cifs: Allow binding to local IP address.

[Steve French]

Ben,
Dr. Holder took a look at this and acked it.
This does help the problem of choosing
wired vs. wireless for mounts to specific servers
(where the default route would be wrong as happened
to me last week) and also there are some IPv6
cases it helps with.

If nfs guys require a different name for the mount
option etc. - let me know.

On Wed, Sep 1, 2010 at 7:06 PM, Ben Greear <greearb@candelatech.com> 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 srcaddr=192.168.1.50,user=foo, ...
>   Usage:  mount -t cifs -o srcaddr=2002::100:1,user=foo, ...
>
> Signed-off-by: Ben Greear <greearb@candelatech.com>
> ---
> :100644 100644 b7431af... 1b6ddd6... M  fs/cifs/cifsfs.c
> :100644 100644 c9d0cfc... 784fd4a... M  fs/cifs/cifsglob.h
> :100644 100644 ec0ea4a... d3a36b4... M  fs/cifs/connect.c
>  fs/cifs/cifsfs.c   |   19 +++++++++++
>  fs/cifs/cifsglob.h |    1 +
>  fs/cifs/connect.c  |   90 ++++++++++++++++++++++++++++++++++++++++++++++++++-
>  3 files changed, 108 insertions(+), 2 deletions(-)
>
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index b7431af..1b6ddd6 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -36,6 +36,7 @@
>  #include <linux/kthread.h>
>  #include <linux/freezer.h>
>  #include <linux/smp_lock.h>
> +#include <net/ipv6.h>
>  #include "cifsfs.h"
>  #include "cifspdu.h"
>  #define DECLARE_GLOBALS_HERE
> @@ -367,6 +368,8 @@ cifs_show_options(struct seq_file *s, struct vfsmount *m)
>  {
>        struct cifs_sb_info *cifs_sb = CIFS_SB(m->mnt_sb);
>        struct cifsTconInfo *tcon = cifs_sb->tcon;
> +       struct sockaddr *srcaddr;
> +       srcaddr = (struct sockaddr *)&tcon->ses->server->srcaddr;
>
>        seq_printf(s, ",unc=%s", tcon->treeName);
>        if (tcon->ses->userName)
> @@ -374,6 +377,22 @@ cifs_show_options(struct seq_file *s, struct vfsmount *m)
>        if (tcon->ses->domainName)
>                seq_printf(s, ",domain=%s", tcon->ses->domainName);
>
> +       if (srcaddr->sa_family != AF_UNSPEC) {
> +               struct sockaddr_in *saddr4;
> +               struct sockaddr_in6 *saddr6;
> +               saddr4 = (struct sockaddr_in *)srcaddr;
> +               saddr6 = (struct sockaddr_in6 *)srcaddr;
> +               if (srcaddr->sa_family == AF_INET6)
> +                       seq_printf(s, ",srcaddr=%pI6c",
> +                                  &saddr6->sin6_addr);
> +               else if (srcaddr->sa_family == AF_INET)
> +                       seq_printf(s, ",srcaddr=%pI4",
> +                                  &saddr4->sin_addr.s_addr);
> +               else
> +                       seq_printf(s, ",srcaddr=BAD-AF:%i",
> +                                  (int)(srcaddr->sa_family));
> +       }
> +
>        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..784fd4a 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;
> +       struct sockaddr_storage srcaddr; /* locally bind to this 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..d3a36b4 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;
> +       struct sockaddr_storage srcaddr; /* allow binding to a local IP */
>        struct nls_table *local_nls;
>  };
>
> @@ -1064,6 +1065,22 @@ cifs_parse_mount_options(char *options, const char *devname,
>                                                    "long\n");
>                                return 1;
>                        }
> +               } else if (strnicmp(data, "srcaddr", 7) == 0) {
> +                       vol->srcaddr.ss_family = AF_UNSPEC;
> +
> +                       if (!value || !*value) {
> +                               printk(KERN_WARNING "CIFS: srcaddr value"
> +                                      " not specified.\n");
> +                               return 1;       /* needs_arg; */
> +                       }
> +                       i = cifs_convert_address((struct sockaddr *)&vol->srcaddr,
> +                                                value, strlen(value));
> +                       if (i < 0) {
> +                               printk(KERN_WARNING "CIFS:  Could not parse"
> +                                      " srcaddr: %s\n",
> +                                      value);
> +                               return 1;
> +                       }
>                } else if (strnicmp(data, "prefixpath", 10) == 0) {
>                        if (!value || !*value) {
>                                printk(KERN_WARNING
> @@ -1392,8 +1409,36 @@ cifs_parse_mount_options(char *options, const char *devname,
>        return 0;
>  }
>
> +/** Returns true if srcaddr isn't specified and rhs isn't
> + * specified, or if srcaddr is specified and
> + * matches the IP address of the rhs argument.
> + */
> +static bool
> +srcip_matches(struct sockaddr *srcaddr, struct sockaddr *rhs)
> +{
> +       switch (srcaddr->sa_family) {
> +       case AF_UNSPEC:
> +               return (rhs->sa_family == AF_UNSPEC);
> +       case AF_INET: {
> +               struct sockaddr_in *saddr4 = (struct sockaddr_in *)srcaddr;
> +               struct sockaddr_in *vaddr4 = (struct sockaddr_in *)rhs;
> +               return (saddr4->sin_addr.s_addr == vaddr4->sin_addr.s_addr);
> +       }
> +       case AF_INET6: {
> +               struct sockaddr_in6 *saddr6 = (struct sockaddr_in6 *)srcaddr;
> +               struct sockaddr_in6 *vaddr6 = (struct sockaddr_in6 *)&rhs;
> +               return ipv6_addr_equal(&saddr6->sin6_addr, &vaddr6->sin6_addr);
> +       }
> +       default:
> +               WARN_ON(1);
> +               return false; /* don't expect to be here */
> +       }
> +}
> +
> +
>  static bool
> -match_address(struct TCP_Server_Info *server, struct sockaddr *addr)
> +match_address(struct TCP_Server_Info *server, struct sockaddr *addr,
> +             struct sockaddr *srcaddr)
>  {
>        struct sockaddr_in *addr4 = (struct sockaddr_in *)addr;
>        struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)addr;
> @@ -1420,6 +1465,9 @@ match_address(struct TCP_Server_Info *server, struct sockaddr *addr)
>                break;
>        }
>
> +       if (!srcip_matches(srcaddr, (struct sockaddr *)&server->srcaddr))
> +               return false;
> +
>        return true;
>  }
>
> @@ -1487,7 +1535,8 @@ 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,
> +                                  (struct sockaddr *)&vol->srcaddr))
>                        continue;
>
>                if (!match_security(server, vol))
> @@ -1602,6 +1651,8 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
>         * no need to spinlock this init of tcpStatus or srv_count
>         */
>        tcp_ses->tcpStatus = CifsNew;
> +       memcpy(&tcp_ses->srcaddr, &volume_info->srcaddr,
> +              sizeof(tcp_ses->srcaddr));
>        ++tcp_ses->srv_count;
>
>        if (addr.ss_family == AF_INET6) {
> @@ -2026,6 +2077,33 @@ static void rfc1002mangle(char *target, char *source, unsigned int length)
>
>  }
>
> +static int
> +bind_socket(struct TCP_Server_Info *server)
> +{
> +       int rc = 0;
> +       if (server->srcaddr.ss_family != AF_UNSPEC) {
> +               /* Bind to the specified local IP address */
> +               struct socket *socket = server->ssocket;
> +               rc = socket->ops->bind(socket,
> +                                      (struct sockaddr *) &server->srcaddr,
> +                                      sizeof(server->srcaddr));
> +               if (rc < 0) {
> +                       struct sockaddr_in *saddr4;
> +                       struct sockaddr_in6 *saddr6;
> +                       saddr4 = (struct sockaddr_in *)&server->srcaddr;
> +                       saddr6 = (struct sockaddr_in6 *)&server->srcaddr;
> +                       if (saddr6->sin6_family == AF_INET6)
> +                               cERROR(1, "cifs: "
> +                                      "Failed to bind to: %pI6c, error: %d\n",
> +                                      &saddr6->sin6_addr, rc);
> +                       else
> +                               cERROR(1, "cifs: "
> +                                      "Failed to bind to: %pI4, error: %d\n",
> +                                      &saddr4->sin_addr.s_addr, rc);
> +               }
> +       }
> +       return rc;
> +}
>
>  static int
>  ipv4_connect(struct TCP_Server_Info *server)
> @@ -2051,6 +2129,10 @@ ipv4_connect(struct TCP_Server_Info *server)
>                cifs_reclassify_socket4(socket);
>        }
>
> +       rc = bind_socket(server);
> +       if (rc < 0)
> +               return rc;
> +
>        /* user overrode default port */
>        if (server->addr.sockAddr.sin_port) {
>                rc = socket->ops->connect(socket, (struct sockaddr *)
> @@ -2213,6 +2295,10 @@ ipv6_connect(struct TCP_Server_Info *server)
>                cifs_reclassify_socket6(socket);
>        }
>
> +       rc = bind_socket(server);
> +       if (rc < 0)
> +               return rc;
> +
>        /* user overrode default port */
>        if (server->addr.sockAddr6.sin6_port) {
>                rc = socket->ops->connect(socket,
> --
> 1.6.2.5
>
>



-- 
Thanks,

Steve
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Re: [cifs bindaddr v5] cifs: Allow binding to local IP address.

[Ben Greear]

On 09/20/2010 10:44 AM, Steve French wrote:
> Ben,
> Dr. Holder took a look at this and acked it.
> This does help the problem of choosing
> wired vs. wireless for mounts to specific servers
> (where the default route would be wrong as happened
> to me last week) and also there are some IPv6
> cases it helps with.
>
> If nfs guys require a different name for the mount
> option etc. - let me know.

The NFS guys don't seem to see any use at all in
binding to IPs, so I'm not sure they'll ever take
such a patch.

I should have time to test the smb2 patch today
if all goes well...

Thanks,
Ben

-- 
Ben Greear <greearb-my8/4N5VtI7c+919tysfdA@public.gmane.org>
Candela Technologies Inc  http://www.candelatech.com