statd: Add API to canonicalize mon_names

Provide a shared function to generate canonical names that statd
uses to index its on-disk monitor list.  This function can resolve
DNS hostnames, and IPv4 and IPv6 presentation addresses.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/utils/statd/hostname.c b/utils/statd/hostname.c
index 7571b6f44a864318ef28425e58b07fcfea154efb..7d704cc6654c67c8bdf7e14e70967dfdf7776d34 100644 (file)
--- a/utils/statd/hostname.c
+++ b/utils/statd/hostname.c
@@ -39,6 +39,10 @@
 #include "statd.h"
 #include "xlog.h"
 
+#ifndef HAVE_DECL_AI_ADDRCONFIG
+#define AI_ADDRCONFIG  0
+#endif
+
 /**
  * statd_present_address - convert sockaddr to presentation address
  * @sap: pointer to socket address to convert
@@ -126,6 +130,103 @@ get_addrinfo(const char *hostname, const struct addrinfo *hint)
        return NULL;
 }
 
+#ifdef HAVE_GETNAMEINFO
+static _Bool
+get_nameinfo(const struct sockaddr *sap, const socklen_t salen,
+               /*@out@*/ char *buf, const socklen_t buflen)
+{
+       int error;
+
+       error = getnameinfo(sap, salen, buf, buflen, NULL, 0, NI_NAMEREQD);
+       if (error != 0) {
+               xlog(D_GENERAL, "%s: failed to resolve address: %s",
+                               __func__, gai_strerror(error));
+               return false;
+       }
+
+       return true;
+}
+#else  /* !HAVE_GETNAMEINFO */
+static _Bool
+get_nameinfo(const struct sockaddr *sap,
+               __attribute__ ((unused)) const socklen_t salen,
+               /*@out@*/ char *buf, socklen_t buflen)
+{
+       struct sockaddr_in *sin = (struct sockaddr_in *)(char *)sap;
+       struct hostent *hp;
+
+       if (sin->sin_family != AF_INET) {
+               xlog(D_GENERAL, "%s: unknown address family: %d",
+                               sin->sin_family);
+               return false;
+       }
+
+       hp = gethostbyaddr((const char *)&(sin->sin_addr.s_addr),
+                               sizeof(struct in_addr), AF_INET);
+       if (hp == NULL) {
+               xlog(D_GENERAL, "%s: failed to resolve address: %m", __func__);
+               return false;
+       }
+
+       strncpy(buf, hp->h_name, (size_t)buflen);
+       return true;
+}
+#endif /* !HAVE_GETNAMEINFO */
+
+/**
+ * statd_canonical_name - choose file name for monitor record files
+ * @hostname: C string containing hostname or presentation address
+ *
+ * Returns a '\0'-terminated ASCII string containing a fully qualified
+ * canonical hostname, or NULL if @hostname does not have a reverse
+ * mapping.  Caller must free the result with free(3).
+ *
+ * Incoming hostnames are looked up to determine the canonical hostname,
+ * and incoming presentation addresses are converted to canonical
+ * hostnames.
+ *
+ * We won't monitor peers that don't have a reverse map.  The canonical
+ * name gives us a key for our monitor list.
+ */
+__attribute_malloc__
+char *
+statd_canonical_name(const char *hostname)
+{
+       struct addrinfo hint = {
+#ifdef IPV6_SUPPORTED
+               .ai_family      = AF_UNSPEC,
+#else  /* !IPV6_SUPPORTED */
+               .ai_family      = AF_INET,
+#endif /* !IPV6_SUPPORTED */
+               .ai_flags       = AI_NUMERICHOST,
+               .ai_protocol    = (int)IPPROTO_UDP,
+       };
+       char buf[NI_MAXHOST];
+       struct addrinfo *ai;
+
+       ai = get_addrinfo(hostname, &hint);
+       if (ai != NULL) {
+               /* @hostname was a presentation address */
+               _Bool result;
+               result = get_nameinfo(ai->ai_addr, ai->ai_addrlen,
+                                       buf, (socklen_t)sizeof(buf));
+               freeaddrinfo(ai);
+               if (!result)
+                       return NULL;
+               return strdup(buf);
+       }
+
+       /* @hostname was a hostname */
+       hint.ai_flags = AI_CANONNAME;
+       ai = get_addrinfo(hostname, &hint);
+       if (ai == NULL)
+               return NULL;
+       strcpy(buf, ai->ai_canonname);
+       freeaddrinfo(ai);
+
+       return strdup(buf);
+}
+
 /**
  * statd_matchhostname - check if two hostnames are equivalent
  * @hostname1: C string containing hostname

diff --git a/utils/statd/statd.h b/utils/statd/statd.h
index c2d5956ec3329147d0d9ec8274da6ba9b650ad82..e89e666d9cae977e5cad8f07c0144ecb3f6b4d98 100644 (file)
--- a/utils/statd/statd.h
+++ b/utils/statd/statd.h
@@ -25,6 +25,8 @@
 extern _Bool   statd_matchhostname(const char *hostname1, const char *hostname2);
 extern _Bool   statd_present_address(const struct sockaddr *sap, char *buf,
                                        const size_t buflen);
+__attribute_malloc__
+extern char *  statd_canonical_name(const char *hostname);
 
 extern void    my_svc_run(void);
 extern void    notify_hosts(void);