cifs: Allow binding to local IP address.

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, ...

Acked-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Dr. David Holder <david.holder@erion.co.uk>
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index b7431afdd76d..1b6ddd6f760f 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");