RDMA/cma: Allow user to restrict listens to bound address family

Provide an option for the user to specify that listens should only
accept connections where the incoming address family matches that of
the locally bound address.  This is used to support the equivalent of
IPV6_V6ONLY socket option, which allows an app to only accept
connection requests directed to IPv6 addresses.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

2 files changed, 38 insertions, 4 deletions

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 454e7ea111e6..8734a6af35d7 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -99,6 +99,10 @@ struct rdma_bind_list {
         unsigned short          port;
 };
 
+enum {
+        CMA_OPTION_AFONLY,
+};
+
 /*
  * Device removal can occur at anytime, so we need extra handling to
  * serialize notifying the user of device removal with other callbacks.
@@ -137,6 +141,7 @@ struct rdma_id_private {
         u32                     qkey;
         u32                     qp_num;
         pid_t                   owner;
+        u32                     options;
         u8                      srq;
         u8                      tos;
         u8                      reuseaddr;
@@ -2104,6 +2109,26 @@ int rdma_set_reuseaddr(struct rdma_cm_id *id, int reuse)
 }
 EXPORT_SYMBOL(rdma_set_reuseaddr);
 
+int rdma_set_afonly(struct rdma_cm_id *id, int afonly)
+{
+        struct rdma_id_private *id_priv;
+        unsigned long flags;
+        int ret;
+
+        id_priv = container_of(id, struct rdma_id_private, id);
+        spin_lock_irqsave(&id_priv->lock, flags);
+        if (id_priv->state == RDMA_CM_IDLE || id_priv->state == RDMA_CM_ADDR_BOUND) {
+                id_priv->options |= (1 << CMA_OPTION_AFONLY);
+                id_priv->afonly = afonly;
+                ret = 0;
+        } else {
+                ret = -EINVAL;
+        }
+        spin_unlock_irqrestore(&id_priv->lock, flags);
+        return ret;
+}
+EXPORT_SYMBOL(rdma_set_afonly);
+
 static void cma_bind_port(struct rdma_bind_list *bind_list,
                           struct rdma_id_private *id_priv)
 {
@@ -2379,12 +2404,14 @@ int rdma_bind_addr(struct rdma_cm_id *id, struct sockaddr *addr)
         }
 
         memcpy(&id->route.addr.src_addr, addr, ip_addr_size(addr));
-        if (addr->sa_family == AF_INET)
-                id_priv->afonly = 1;
+        if (!(id_priv->options & (1 << CMA_OPTION_AFONLY))) {
+                if (addr->sa_family == AF_INET)
+                        id_priv->afonly = 1;
 #if IS_ENABLED(CONFIG_IPV6)
-        else if (addr->sa_family == AF_INET6)
-                id_priv->afonly = init_net.ipv6.sysctl.bindv6only;
+                else if (addr->sa_family == AF_INET6)
+                        id_priv->afonly = init_net.ipv6.sysctl.bindv6only;
 #endif
+        }
         ret = cma_get_port(id_priv);
         if (ret)
                 goto err2;
diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index 8002ae642cfe..893cb879462c 100644
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -909,6 +909,13 @@ static int ucma_set_option_id(struct ucma_context *ctx, int optname,
                 }
                 ret = rdma_set_reuseaddr(ctx->cm_id, *((int *) optval) ? 1 : 0);
                 break;
+        case RDMA_OPTION_ID_AFONLY:
+                if (optlen != sizeof(int)) {
+                        ret = -EINVAL;
+                        break;
+                }
+                ret = rdma_set_afonly(ctx->cm_id, *((int *) optval) ? 1 : 0);
+                break;
         default:
                 ret = -ENOSYS;
         }