Improve error message when binding http port.

[darkstat] / dns.c

diff --git a/dns.c b/dns.c
index 60c9243..e8bdbb4 100644 (file)
--- a/dns.c
+++ b/dns.c
@@ -1,5 +1,5 @@
 /* darkstat 3
- * copyright (c) 2001-2008 Emil Mikulic.
+ * copyright (c) 2001-2011 Emil Mikulic.
  *
  * dns.c: synchronous DNS in a child process.
  *
@@ -7,7 +7,7 @@
  * GNU General Public License version 2. (see COPYING.GPL)
  */
 
-#include "darkstat.h"
+#include "cdefs.h"
 #include "conv.h"
 #include "decode.h"
 #include "dns.h"
@@ -16,6 +16,7 @@
 #include "queue.h"
 #include "str.h"
 #include "tree.h"
+#include "bsd.h" /* for setproctitle, strlcpy */
 
 #include <sys/param.h>
 #include <sys/socket.h>
@@ -38,7 +39,7 @@ static pid_t pid = -1;
 struct dns_reply {
    struct addr addr;
    int error; /* for gai_strerror(), or 0 if no error */
-   char name[MAXHOSTNAMELEN];
+   char name[256]; /* http://tools.ietf.org/html/rfc1034#section-3.1 */
 };
 
 void
@@ -186,12 +187,6 @@ dns_get_result(struct addr *ipaddr, char **name)
 
    /* Return successful reply. */
    memcpy(ipaddr, &reply.addr, sizeof(*ipaddr));
-#if DARKSTAT_USES_HOSTENT
-   if (reply.error != 0)
-      xasprintf(name, "(%s)", hstrerror(reply.error));
-   else
-      *name = xstrdup(reply.name);
-#else /* !DARKSTAT_USES_HOSTENT */
    if (reply.error != 0) {
       /* Identify common special cases.  */
       const char *type = "none";
@@ -203,15 +198,15 @@ dns_get_result(struct addr *ipaddr, char **name)
             type = "site-local";
          else if (IN6_IS_ADDR_MULTICAST(&reply.addr.ip.v6))
             type = "multicast";
-      } else { /* AF_INET */
-         if (IN_MULTICAST(reply.addr.ip.v4))
+      } else {
+         assert(reply.addr.family == IPv4);
+         if (IN_MULTICAST(htonl(reply.addr.ip.v4)))
             type = "multicast";
       }
       xasprintf(name, "(%s)", type);
    }
    else  /* Correctly resolved name.  */
       *name = xstrdup(reply.name);
-#endif /* !DARKSTAT_USES_HOSTENT */
 
    dns_unqueue(&reply.addr);
    return (1);
@@ -301,9 +296,7 @@ dns_main(void)
 {
    struct addr ip;
 
-#ifdef HAVE_SETPROCTITLE
    setproctitle("DNS child");
-#endif
    fd_set_nonblock(sock[CHILD]);
    verbosef("DNS child entering main DNS loop");
    for (;;) {
@@ -345,30 +338,9 @@ dns_main(void)
       /* Process queue. */
       if (dequeue(&ip)) {
          struct dns_reply reply;
-#if DARKSTAT_USES_HOSTENT
-         struct hostent *he;
-
-         memcpy(&reply.addr, &ip, sizeof(reply.addr));
-         he = gethostbyaddr((char *)&ip.addr.ip, sizeof(ip.addr.ip), ip.af); /* TODO MEA */
-
-         /* On some platforms (for example Linux with GLIBC 2.3.3), h_errno
-          * will be non-zero here even though the lookup succeeded.
-          */
-         if (he == NULL) {
-            reply.name[0] = '\0';
-            reply.error = h_errno;
-         } else {
-            assert(sizeof(reply.name) > sizeof(char *)); /* not just a ptr */
-            strlcpy(reply.name, he->h_name, sizeof(reply.name));
-            reply.error = 0;
-         }
-         fd_set_block(sock[CHILD]);
-         xwrite(sock[CHILD], &reply, sizeof(reply));
-         verbosef("DNS: %s is %s", addr_to_str(&reply.addr),
-            (h_errno == 0)?reply.name:hstrerror(h_errno));
-#else /* !DARKSTAT_USES_HOSTENT */
          struct sockaddr_in sin;
          struct sockaddr_in6 sin6;
+         struct hostent *he;
          char host[NI_MAXHOST];
          int ret, flags;
 
@@ -383,6 +355,19 @@ dns_main(void)
                sin.sin_addr.s_addr = ip.ip.v4;
                ret = getnameinfo((struct sockaddr *) &sin, sizeof(sin),
                                  host, sizeof(host), NULL, 0, flags);
+               if (ret == EAI_FAMILY) {
+                  verbosef("getnameinfo error %s, trying gethostbyname",
+                     gai_strerror(ret));
+                  he = gethostbyaddr(&sin.sin_addr.s_addr,
+                     sizeof(sin.sin_addr.s_addr), sin.sin_family);
+                  if (he == NULL) {
+                     ret = EAI_FAIL;
+                     verbosef("gethostbyname error %s", hstrerror(h_errno));
+                  } else {
+                     ret = 0;
+                     strlcpy(host, he->h_name, sizeof(host));
+                  }
+               }
                break;
             case IPv6:
                sin6.sin6_family = AF_INET6;
@@ -406,7 +391,6 @@ dns_main(void)
          xwrite(sock[CHILD], &reply, sizeof(reply));
          verbosef("DNS: %s is \"%s\".", addr_to_str(&reply.addr),
             (ret == 0) ? reply.name : gai_strerror(ret));
-#endif /* !DARKSTAT_USES_HOSTENT */
       }
    }
 }