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@xxxxxxxxxx>
---
utils/statd/hostname.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++++
utils/statd/statd.h | 2 +
2 files changed, 103 insertions(+), 0 deletions(-)
diff --git a/utils/statd/hostname.c b/utils/statd/hostname.c
index 7571b6f..7d704cc 100644
--- 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 c2d5956..e89e666 100644
--- 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);
--
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