On 08/31/2010 07:06 AM, Jeff Layton wrote:
On Mon, 30 Aug 2010 22:40:22 -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 srcaddr=192.168.1.50,user=foo, ...
Usage: mount -t cifs -o srcaddr=2002::100:1,user=foo, ...
+bool
+cifs_addr_is_specified(struct sockaddr *srcaddr) {
+ struct sockaddr_in *saddr4 = (struct sockaddr_in *)srcaddr;
+ struct sockaddr_in6 *saddr6 = (struct sockaddr_in6 *)srcaddr;
+ switch (srcaddr->sa_family) {
+ case AF_INET:
+ return saddr4->sin_addr.s_addr != 0;
^^^^
nit: should probably be htonl(INADDR_ANY)
We don't initialize it to INADDR_ANY, so I'd rather not check
against it, even though now and forever it's going to be zero.
But, will change if that's the consensus.
@@ -1064,6 +1066,22 @@ cifs_parse_mount_options(char *options, const char *devname,
"long\n");
return 1;
}
+ } else if (strnicmp(data, "srcaddr", 8) == 0) {
+ memset(&vol->srcaddr, 0, sizeof(vol->srcaddr));
^^^^^^^^^
Is this necessary? vol is kzalloc'ed so it
should be zeroed out already. Or are you
worried about people specifying srcaddr= more
than once?
It just seems cleaner in general to set it to known value in case errors
later in that method keep us from setting it to a proper new value.
And, certainly useful if it can be set twice somehow..but not sure if that's
currently the case or not.
+
+ 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 +1410,37 @@ cifs_parse_mount_options(char *options, const char *devname,
return 0;
}
+/** Returns true if srcaddr isn't specified or if it matches
+ * the IP address of the rhs argument.
+ */
static bool
-match_address(struct TCP_Server_Info *server, struct sockaddr *addr)
+srcip_matches(struct sockaddr *srcaddr, struct sockaddr *rhs)
+{
+ if (cifs_addr_is_specified(srcaddr)) {
Just wondering what the expected behavior would be here...
Suppose I have a clustered IP address set up, and I want to
ensure that one of my CIFS mounts use that as the srcaddr. Now,
suppose I make another mount to the same server, but don't
specify the srcaddr there. That mount uses the same socket as
the first one (that is bound to the srcaddr). Now, suppose I
unmount the first mount and then fail over the IP address. What
happens to the second one? (Nothing good, I'd wager...)
Perhaps we should consider using a different socket when the
srcaddr isn't specified?
The idea is that each mount with unique source addr gets it's own
cifs session. They will not be shared even if the server is the
same. If srcaddr isn't specified, then you get today's behaviour
(shared so long as server is the same).
In your example, the bound and the un-bound shouldn't share anything,
but it's possible my code doesn't fully do that. If so, I would
consider that a bug.
+ case AF_INET6:
+ if (memcmp(&saddr6->sin6_addr,&vaddr6->sin6_addr,
+ sizeof(saddr6->sin6_addr)) != 0)
^^^ should use ipv6_addr_equal, unless there's some reason not to do so...
addr_equal should be fine, I will change that.
+ return false;
+ break;
+ }
+ }
+ return true;
+}
+
+
+static bool
+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 +1467,9 @@ 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 +1537,8 @@ 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 +1653,8 @@ 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) {
@@ -1678,6 +1731,9 @@ cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb_vol *vol)
vol->password ? vol->password : "",
MAX_PASSWORD_SIZE))
continue;
+ if (!srcip_matches((struct sockaddr *)&server->srcaddr,
+ (struct sockaddr *)&ses->server->srcaddr))
+ continue;
^^^ there should be no need for this. By the
time you get here, you've already determined
whether you can use the same socket as another
one (via the check in match_address).
Ok, I'll remove that.
index ab70a3f..735989a 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -230,6 +230,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
/* IPv6 Wildcard Address and Loopback Address defined by RFC2553 */
const struct in6_addr in6addr_any = IN6ADDR_ANY_INIT;
+EXPORT_SYMBOL(in6addr_any);
There should be no need at all to touch stuff outside of cifs.ko, at
least, not in this patch. If you want to do this, you need to do it as
a separate patch and float it in linux-netdev or someplace like that.
In the meantime, I'd suggest declaring a private in6_addr variable and
initializing it to IN6ADDR_ANY_INIT (similar to what the sunrpc code
does).
Sounds good. I'll see if davem will accept such a patch, and will use
a private copy in cifs until such time as the ipv6 patch goes in.
Thanks for the review!
Thanks,
Ben
--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com
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