Socket creation is unfortunately complicated by the need to handle the
case where sm-notify is built with IPv6 support, but the local system
has disabled it entirely at run-time (ie, socket(3) returns
EAFNOSUPPORT when we try to create an AF_INET6 socket).
The run-time address family setting is made available in the global
variable nsm_family. This setting can control the family of the
socket's bind address and what kind of addresses we want returned by
smn_lookup(). Support for that is added in subsequent patches.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
utils/statd/sm-notify.c | 81 ++++++++++++++++++++++++++++++++++++++++++++---
1 files changed, 76 insertions(+), 5 deletions(-)
diff --git a/utils/statd/sm-notify.c b/utils/statd/sm-notify.c
index 462ba79..0ba817a 100644
--- a/utils/statd/sm-notify.c
+++ b/utils/statd/sm-notify.c
@@ -49,6 +49,7 @@ struct nsm_host {
static char nsm_hostname[256];
static int nsm_state;
+static int nsm_family = AF_INET;
static int opt_debug = 0;
static _Bool opt_update_state = true;
static unsigned int opt_max_retry = 15 * 60;
@@ -141,6 +142,79 @@ smn_get_host(const char *hostname,
return 1;
}
+#ifdef IPV6_SUPPORTED
+static int smn_socket(void)
+{
+ int sock;
+
+ /*
+ * Use an AF_INET socket if IPv6 is disabled on the
+ * local system.
+ */
+ sock = socket(AF_INET6, SOCK_DGRAM, 0);
+ if (sock == -1) {
+ if (errno != EAFNOSUPPORT) {
+ xlog(L_ERROR, "Failed to create RPC socket: %m");
+ return -1;
+ }
+ sock = socket(AF_INET, SOCK_DGRAM, 0);
+ if (sock < 0) {
+ xlog(L_ERROR, "Failed to create RPC socket: %m");
+ return -1;
+ }
+ } else
+ nsm_family = AF_INET6;
+
+ if (fcntl(sock, F_SETFL, O_NONBLOCK) == -1) {
+ xlog(L_ERROR, "fcntl(3) on RPC socket failed: %m");
+ goto out_close;
+ }
+
+ /*
+ * TI-RPC over IPv6 (udp6/tcp6) does not handle IPv4. However,
+ * since sm-notify open-codes all of its RPC support, it can
+ * use a single socket and let the local network stack provide
+ * the correct mapping between address families automatically.
+ * This is the same thing that is done in the kernel.
+ */
+ if (nsm_family == AF_INET6) {
+ const int zero = 0;
+ socklen_t zerolen = (socklen_t)sizeof(zero);
+
+ if (setsockopt(sock, SOL_IPV6, IPV6_V6ONLY,
+ (char *)&zero, zerolen) == -1) {
+ xlog(L_ERROR, "setsockopt(3) on RPC socket failed: %m");
+ goto out_close;
+ }
+ }
+
+ return sock;
+
+out_close:
+ (void)close(sock);
+ return -1;
+}
+#else /* !IPV6_SUPPORTED */
+static int smn_socket(void)
+{
+ int sock;
+
+ sock = socket(AF_INET, SOCK_DGRAM, 0);
+ if (sock == -1) {
+ xlog(L_ERROR, "Failed to create RPC socket: %m");
+ return -1;
+ }
+
+ if (fcntl(sock, F_SETFL, O_NONBLOCK) == -1) {
+ xlog(L_ERROR, "fcntl(3) on RPC socket failed: %m");
+ (void)close(sock);
+ return -1;
+ }
+
+ return sock;
+}
+#endif /* !IPV6_SUPPORTED */
+
/*
* Prepare a socket for sending RPC requests
*
@@ -155,12 +229,9 @@ smn_create_socket(const char *srcaddr, const uint16_t srcport)
int sock, retry_cnt = 0;
retry:
- sock = socket(AF_INET, SOCK_DGRAM, 0);
- if (sock < 0) {
- xlog(L_ERROR, "Failed to create RPC socket: %m");
+ sock = smn_socket();
+ if (sock == -1)
return -1;
- }
- fcntl(sock, F_SETFL, O_NONBLOCK);
memset(&address, 0, sizeof(address));
local_addr->sa_family = AF_INET; /* Default to IPv4 */
--
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