rds: Enable RDS IPv6 support

This patch enables RDS to use IPv6 addresses. For RDS/TCP, the
listener is now an IPv6 endpoint which accepts both IPv4 and IPv6
connection requests.  RDS/RDMA/IB uses a private data (struct
rds_ib_connect_private) exchange between endpoints at RDS connection
establishment time to support RDMA. This private data exchange uses a
32 bit integer to represent an IP address. This needs to be changed in
order to support IPv6. A new private data struct
rds6_ib_connect_private is introduced to handle this. To ensure
backward compatibility, an IPv6 capable RDS stack uses another RDMA
listener port (RDS_CM_PORT) to accept IPv6 connection. And it
continues to use the original RDS_PORT for IPv4 RDS connections. When
it needs to communicate with an IPv6 peer, it uses the RDS_CM_PORT to
send the connection set up request.

v5: Fixed syntax problem (David Miller).

v4: Changed port history comments in rds.h (Sowmini Varadhan).

v3: Added support to set up IPv4 connection using mapped address
    (David Miller).
    Added support to set up connection between link local and non-link
    addresses.
    Various review comments from Santosh Shilimkar and Sowmini Varadhan.

v2: Fixed bound and peer address scope mismatched issue.
    Added back rds_connect() IPv6 changes.

Signed-off-by: Ka-Cheong Poon <ka-cheong.poon@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 5 deletions

diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c
index dd8a867e5a9c..a33b82dc0804 100644
--- a/net/rds/ib_cm.c
+++ b/net/rds/ib_cm.c
@@ -678,7 +678,7 @@ static u32 rds_ib_protocol_compatible(struct rdma_cm_event *event, bool isv6)
         return version;
 }
 
-/* Given an IPv6 address, find the IB net_device which hosts that address and
+/* Given an IPv6 address, find the net_device which hosts that address and
  * return its index.  This is used by the rds_ib_cm_handle_connect() code to
  * find the interface index of where an incoming request comes from when
  * the request is using a link local address.
@@ -695,8 +695,7 @@ static u32 __rds_find_ifindex(struct net *net, const struct in6_addr *addr)
 
         rcu_read_lock();
         for_each_netdev_rcu(net, dev) {
-                if (dev->type == ARPHRD_INFINIBAND &&
-                    ipv6_chk_addr(net, addr, dev, 0)) {
+                if (ipv6_chk_addr(net, addr, dev, 1)) {
                         idx = dev->ifindex;
                         break;
                 }
@@ -736,7 +735,7 @@ int rds_ib_cm_handle_connect(struct rdma_cm_id *cm_id,
                 dp_cmn = &dp->ricp_v6.dp_cmn;
                 saddr6 = &dp->ricp_v6.dp_saddr;
                 daddr6 = &dp->ricp_v6.dp_daddr;
-                /* If the local address is link local, need to find the
+                /* If either address is link local, need to find the
                  * interface index in order to create a proper RDS
                  * connection.
                  */
@@ -748,6 +747,14 @@ int rds_ib_cm_handle_connect(struct rdma_cm_id *cm_id,
                                 err = -EOPNOTSUPP;
                                 goto out;
                         }
+                } else if (ipv6_addr_type(saddr6) & IPV6_ADDR_LINKLOCAL) {
+                        /* Use our address to find the correct index. */
+                        ifindex = __rds_find_ifindex(&init_net, daddr6);
+                        /* No index found...  Need to bail out. */
+                        if (ifindex == 0) {
+                                err = -EOPNOTSUPP;
+                                goto out;
+                        }
                 }
         } else {
                 dp_cmn = &dp->ricp_v4.dp_cmn;
@@ -886,7 +893,10 @@ int rds_ib_conn_path_connect(struct rds_conn_path *cp)
 
         /* XXX I wonder what affect the port space has */
         /* delegate cm event handler to rdma_transport */
-        handler = rds_rdma_cm_event_handler;
+        if (conn->c_isv6)
+                handler = rds6_rdma_cm_event_handler;
+        else
+                handler = rds_rdma_cm_event_handler;
         ic->i_cm_id = rdma_create_id(&init_net, handler, conn,
                                      RDMA_PS_TCP, IB_QPT_RC);
         if (IS_ERR(ic->i_cm_id)) {