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, 42 insertions, 12 deletions

diff --git a/net/rds/tcp_connect.c b/net/rds/tcp_connect.c
index 231ae927858e..008f50fb25dd 100644
--- a/net/rds/tcp_connect.c
+++ b/net/rds/tcp_connect.c
@@ -89,9 +89,11 @@ out:
 int rds_tcp_conn_path_connect(struct rds_conn_path *cp)
 {
         struct socket *sock = NULL;
+        struct sockaddr_in6 sin6;
         struct sockaddr_in sin;
         struct sockaddr *addr;
         int addrlen;
+        bool isv6;
         int ret;
         struct rds_connection *conn = cp->cp_conn;
         struct rds_tcp_connection *tc = cp->cp_transport_data;
@@ -108,18 +110,36 @@ int rds_tcp_conn_path_connect(struct rds_conn_path *cp)
                 mutex_unlock(&tc->t_conn_path_lock);
                 return 0;
         }
-        ret = sock_create_kern(rds_conn_net(conn), PF_INET,
-                               SOCK_STREAM, IPPROTO_TCP, &sock);
+        if (ipv6_addr_v4mapped(&conn->c_laddr)) {
+                ret = sock_create_kern(rds_conn_net(conn), PF_INET,
+                                       SOCK_STREAM, IPPROTO_TCP, &sock);
+                isv6 = false;
+        } else {
+                ret = sock_create_kern(rds_conn_net(conn), PF_INET6,
+                                       SOCK_STREAM, IPPROTO_TCP, &sock);
+                isv6 = true;
+        }
+
         if (ret < 0)
                 goto out;
 
         rds_tcp_tune(sock);
 
-        sin.sin_family = AF_INET;
-        sin.sin_addr.s_addr = conn->c_laddr.s6_addr32[3];
-        sin.sin_port = 0;
-        addr = (struct sockaddr *)&sin;
-        addrlen = sizeof(sin);
+        if (isv6) {
+                sin6.sin6_family = AF_INET6;
+                sin6.sin6_addr = conn->c_laddr;
+                sin6.sin6_port = 0;
+                sin6.sin6_flowinfo = 0;
+                sin6.sin6_scope_id = conn->c_dev_if;
+                addr = (struct sockaddr *)&sin6;
+                addrlen = sizeof(sin6);
+        } else {
+                sin.sin_family = AF_INET;
+                sin.sin_addr.s_addr = conn->c_laddr.s6_addr32[3];
+                sin.sin_port = 0;
+                addr = (struct sockaddr *)&sin;
+                addrlen = sizeof(sin);
+        }
 
         ret = sock->ops->bind(sock, addr, addrlen);
         if (ret) {
@@ -128,11 +148,21 @@ int rds_tcp_conn_path_connect(struct rds_conn_path *cp)
                 goto out;
         }
 
-        sin.sin_family = AF_INET;
-        sin.sin_addr.s_addr = conn->c_faddr.s6_addr32[3];
-        sin.sin_port = htons(RDS_TCP_PORT);
-        addr = (struct sockaddr *)&sin;
-        addrlen = sizeof(sin);
+        if (isv6) {
+                sin6.sin6_family = AF_INET6;
+                sin6.sin6_addr = conn->c_faddr;
+                sin6.sin6_port = htons(RDS_TCP_PORT);
+                sin6.sin6_flowinfo = 0;
+                sin6.sin6_scope_id = conn->c_dev_if;
+                addr = (struct sockaddr *)&sin6;
+                addrlen = sizeof(sin6);
+        } else {
+                sin.sin_family = AF_INET;
+                sin.sin_addr.s_addr = conn->c_faddr.s6_addr32[3];
+                sin.sin_port = htons(RDS_TCP_PORT);
+                addr = (struct sockaddr *)&sin;
+                addrlen = sizeof(sin);
+        }
 
         /*
          * once we call connect() we can start getting callbacks and they