[monitoring-plugins] check_curl: fixed DNS caching for SSL hostnames ...
Andreas Baumann
git at monitoring-plugins.org
Sun Jul 25 18:40:13 CEST 2021
Module: monitoring-plugins
Branch: feature_check_curl
Commit: 3f5c54c7830b0529030bb08e2c333497e70b6eb1
Author: Andreas Baumann <mail at andreasbaumann.cc>
Date: Sun Jul 25 18:39:07 2021 +0200
URL: https://www.monitoring-plugins.org/repositories/monitoring-plugins/commit/?id=3f5c54c
check_curl: fixed DNS caching for SSL hostnames (avoid CURLOPT_RESOLVE entry errors)
---
plugins/check_curl.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 51 insertions(+), 3 deletions(-)
diff --git a/plugins/check_curl.c b/plugins/check_curl.c
index ba08c36..2c91a27 100644
--- a/plugins/check_curl.c
+++ b/plugins/check_curl.c
@@ -59,6 +59,8 @@ const char *email = "devel at monitoring-plugins.org";
#include <openssl/opensslv.h>
#endif
+#include <netdb.h>
+
#define MAKE_LIBCURL_VERSION(major, minor, patch) ((major)*0x10000 + (minor)*0x100 + (patch))
#define DEFAULT_BUFFER_SIZE 2048
@@ -370,12 +372,55 @@ handle_curl_option_return_code (CURLcode res, const char* option)
}
int
+lookup_host (const char *host, char *buf, size_t buflen)
+{
+ struct addrinfo hints, *res, *result;
+ int errcode;
+ void *ptr;
+
+ memset (&hints, 0, sizeof (hints));
+ hints.ai_family = address_family;
+ hints.ai_socktype = SOCK_STREAM;
+ hints.ai_flags |= AI_CANONNAME;
+
+ errcode = getaddrinfo (host, NULL, &hints, &result);
+ if (errcode != 0)
+ return errcode;
+
+ res = result;
+
+ while (res) {
+ inet_ntop (res->ai_family, res->ai_addr->sa_data, buf, buflen);
+ switch (res->ai_family) {
+ case AF_INET:
+ ptr = &((struct sockaddr_in *) res->ai_addr)->sin_addr;
+ break;
+ case AF_INET6:
+ ptr = &((struct sockaddr_in6 *) res->ai_addr)->sin6_addr;
+ break;
+ }
+ inet_ntop (res->ai_family, ptr, buf, buflen);
+ if (verbose >= 1)
+ printf ("* getaddrinfo IPv%d address: %s\n",
+ res->ai_family == PF_INET6 ? 6 : 4, buf);
+ res = res->ai_next;
+ }
+
+ freeaddrinfo(result);
+
+ return 0;
+}
+
+int
check_http (void)
{
int result = STATE_OK;
int page_len = 0;
int i;
char *force_host_header = NULL;
+ struct curl_slist *host = NULL;
+ char addrstr[100];
+ char dnscache[DEFAULT_BUFFER_SIZE];
/* initialize curl */
if (curl_global_init (CURL_GLOBAL_DEFAULT) != CURLE_OK)
@@ -418,9 +463,12 @@ check_http (void)
// fill dns resolve cache to make curl connect to the given server_address instead of the host_name, only required for ssl, because we use the host_name later on to make SNI happy
if(use_ssl && host_name != NULL) {
- struct curl_slist *host = NULL;
- char dnscache[DEFAULT_BUFFER_SIZE];
- snprintf (dnscache, DEFAULT_BUFFER_SIZE, "%s:%d:%s", host_name, server_port, server_address);
+ if ( (res=lookup_host (server_address, addrstr, 100)) != 0) {
+ snprintf (msg, DEFAULT_BUFFER_SIZE, _("Unable to lookup IP address for '%s': getaddrinfo returned %d - %s"),
+ server_address, res, gai_strerror (res));
+ die (STATE_CRITICAL, "HTTP CRITICAL - %s\n", msg);
+ }
+ snprintf (dnscache, DEFAULT_BUFFER_SIZE, "%s:%d:%s", host_name, server_port, addrstr);
host = curl_slist_append(NULL, dnscache);
curl_easy_setopt(curl, CURLOPT_RESOLVE, host);
if (verbose>=1)
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