In order to advertise NFS-related services on IPv6 interfaces via
rpcbind, the kernel RPC server implementation must use
rpcb_v4_register() instead of rpcb_register().
A new kernel build option allows distributions to use the legacy
v2 call until they integrate an appropriate user-space rpcbind
daemon that can support IPv6 RPC services.
I tried adding some automatic logic to fall back if registering
with a v4 protocol request failed, but there are too many corner
cases. So I just made it a compile-time switch that distributions
can throw when they've replaced portmapper with rpcbind.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
fs/Kconfig | 22 ++++++++++
include/linux/sunrpc/svc.h | 4 +-
net/sunrpc/svc.c | 95 +++++++++++++++++++++++++++++++++++++++++---
3 files changed, 113 insertions(+), 8 deletions(-)
diff --git a/fs/Kconfig b/fs/Kconfig
index d387358..949e6d1 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -1765,6 +1765,28 @@ config SUNRPC_XPRT_RDMA
If unsure, say N.
+config SUNRPC_REGISTER_V4
+ bool "Register local RPC services via rpcbind v4 (EXPERIMENTAL)"
+ depends on SUNRPC && EXPERIMENTAL
+ default n
+ help
+ Sun added support for registering RPC services at an IPv6
+ address by creating two new versions of the rpcbind protocol
+ (RFC 1833).
+
+ This option enables support in the kernel RPC server for
+ registering kernel RPC services via version 4 of the rpcbind
+ protocol. If you enable this option, you must run a portmapper
+ daemon that supports rpcbind protocol version 4.
+
+ Serving NFS over IPv6 from knfsd (the kernel's NFS server)
+ requires that you enable this option and use a portmapper that
+ supports rpcbind version 4.
+
+ If unsure, say N to get traditional behavior (register kernel
+ RPC services using only rpcbind version 2). Distributions
+ using the legacy Linux portmapper daemon must say N here.
+
config RPCSEC_GSS_KRB5
tristate "Secure RPC: Kerberos V mechanism (EXPERIMENTAL)"
depends on SUNRPC && EXPERIMENTAL
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index a794d4a..2a41d29 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -395,7 +395,9 @@ struct svc_serv * svc_create_pooled(struct svc_program *, unsigned int,
int svc_set_num_threads(struct svc_serv *, struct svc_pool *, int);
void svc_destroy(struct svc_serv *);
int svc_process(struct svc_rqst *);
-int svc_register(struct svc_serv *, int, unsigned short);
+int svc_register(const struct svc_serv *, const unsigned short,
+ const unsigned short);
+
void svc_wake_up(struct svc_serv *);
void svc_reserve(struct svc_rqst *rqstp, int space);
struct svc_pool * svc_pool_for_cpu(struct svc_serv *serv, int cpu);
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 3d4c0b0..c023cb3 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -720,13 +720,92 @@ svc_exit_thread(struct svc_rqst *rqstp)
}
EXPORT_SYMBOL(svc_exit_thread);
+#ifdef CONFIG_SUNRPC_REGISTER_V4
/*
- * Register an RPC service with the local portmapper.
- * To unregister a service, call this routine with
- * proto and port == 0.
+ * Registering kernel RPC services with rpcbind version 2 will work
+ * over either IPv4 or IPv6, since the Linux kernel always registers
+ * services for the "any" address.
+ *
+ * However, the local rpcbind daemon listens on either only AF_INET
+ * or AF_INET6 (never both). When it listens on AF_INET6, an rpcbind
+ * version 2 registration will result in registering the service at
+ * IN6ADDR_ANY, even if the RPC service being registered is not
+ * IPv6-enabled.
+ *
+ * Rpcbind version 4 allows us to be a little more specific. Kernel
+ * RPC services that don't yet support AF_INET6 can register
+ * themselves as IPv4-only with the local rpcbind daemon, even if the
+ * daemon is listening only on AF_INET6.
+ *
+ * And, registering IPv6-enabled kernel RPC services via AF_INET6
+ * verifies that the local user space rpcbind daemon is properly
+ * configured to support remote AF_INET6 rpcbind requests.
+ *
+ * An AF_INET6 registration request will fail if the local rpcbind
+ * daemon is not set up to listen on AF_INET6. Likewise, we fail
+ * AF_INET6 registration requests if svc_register() is configured to
+ * support only rpcbind version 2.
*/
-int
-svc_register(struct svc_serv *serv, int proto, unsigned short port)
+static int __svc_register(const u32 program, const u32 version,
+ const sa_family_t family,
+ const unsigned short protocol,
+ const unsigned short port)
+{
+ struct sockaddr_in sin = {
+ .sin_family = AF_INET,
+ .sin_addr.s_addr = htonl(INADDR_ANY),
+ .sin_port = htons(port),
+ };
+ struct sockaddr_in6 sin6 = {
+ .sin6_family = AF_INET6,
+ .sin6_addr = IN6ADDR_ANY_INIT,
+ .sin6_port = htons(port),
+ };
+ struct sockaddr *sap;
+ char *netid;
+
+ switch (family) {
+ case AF_INET:
+ sap = (struct sockaddr *)&sin;
+ netid = RPCBIND_NETID_TCP;
+ if (protocol == IPPROTO_UDP)
+ netid = RPCBIND_NETID_UDP;
+ break;
+ case AF_INET6:
+ sap = (struct sockaddr *)&sin6;
+ netid = RPCBIND_NETID_TCP6;
+ if (protocol == IPPROTO_UDP)
+ netid = RPCBIND_NETID_UDP6;
+ break;
+ default:
+ return -EAFNOSUPPORT;
+ }
+
+ return rpcb_v4_register(program, version, sap, netid);
+}
+#else
+static int __svc_register(const u32 program, const u32 version,
+ sa_family_t family,
+ const unsigned short protocol,
+ const unsigned short port)
+{
+ if (family != AF_INET)
+ return -EAFNOSUPPORT;
+
+ return rpcb_register(program, version, protocol, port);
+}
+#endif
+
+/**
+ * svc_register - register an RPC service with the local portmapper
+ * @serv: svc_serv struct for the service to register
+ * @proto: transport protocol number to advertise
+ * @port: port to advertise
+ *
+ * Service is registered for any address in serv's address family
+ */
+int svc_register(const struct svc_serv *serv, const unsigned short proto,
+ const unsigned short port)
{
struct svc_program *progp;
unsigned int i;
@@ -739,8 +818,9 @@ svc_register(struct svc_serv *serv, int proto, unsigned short port)
if (progp->pg_vers[i] == NULL)
continue;
- dprintk("svc: svc_register(%s, %s, %d, %d)%s\n",
+ dprintk("svc: svc_register(%s, %u, %s, %u, %d)%s\n",
progp->pg_name,
+ serv->sv_family,
proto == IPPROTO_UDP? "udp" : "tcp",
port,
i,
@@ -750,7 +830,8 @@ svc_register(struct svc_serv *serv, int proto, unsigned short port)
if (progp->pg_vers[i]->vs_hidden)
continue;
- error = rpcb_register(progp->pg_prog, i, proto, port);
+ error = __svc_register(progp->pg_prog, i,
+ serv->sv_family, proto, port);
if (error < 0)
break;
}
--
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