On Wed, 1 Sep 2010 12:00:06 -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, ...
>
> Signed-off-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
> ---
> :100644 100644 b7431af... 25590d2... 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 | 16 +++++++++
> fs/cifs/cifsglob.h | 1 +
> fs/cifs/connect.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++-
> 3 files changed, 105 insertions(+), 2 deletions(-)
>
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index b7431af..25590d2 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);
^^^ nit: parens not needed here
>
> seq_printf(s, ",unc=%s", tcon->treeName);
> if (tcon->ses->userName)
> @@ -374,6 +377,19 @@ 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 (saddr6->sin6_family == AF_INET6)
> + seq_printf(s, ",srcaddr=%pI6c",
> + &saddr6->sin6_addr);
> + else
> + seq_printf(s, ",srcaddr=%pI4",
> + &saddr4->sin_addr.s_addr);
^^^ It's unlikely to occur, but maybe better to make
this a switch() and have a default: case that doesn't
prints the address as "(unknown)" or something? It's
usually better to code defensively for this sort of
stuff and printing a garbage address may be confusing
for users.
> + }
> +
> 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);
> + }
^^^^^
These curly braces aren't needed.
> + default:
> + WARN_ON(1);
Again, I'm not a huge fan of the cERROR and cFYI macros, but they are
our "standard". This would probably be best as a cERROR macro. You
should probably also have it print the value of srcaddr->sa_family as
that may be useful for debugging.
> + return false; /* don't expect to be here */
> + }
> +}
Does the above generate a compiler warning about reaching end of a
non-void function? Either way, it's less clear. I'd change the default
to just fall through and move the "return false" outside the switch.
> +
> +
> 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,
Nice work so far.
--
Jeff Layton <jlayton@xxxxxxxxx>
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