Added alternative resolver.

Altered display of totals.

resolver.c

@@ -14,11 +14,18 @@
 #include <errno.h>
 #include <string.h>
 
+#ifdef USELIBRESOLV
+#include <arpa/nameser.h>
+#include <resolv.h>
+#endif
+
 #include "ns_hash.h"
 #include "iftop.h"
 
 #include "threadprof.h"
 
+
+
 #define RESOLVE_QUEUE_LENGTH 20
 
 struct in_addr resolve_queue[RESOLVE_QUEUE_LENGTH];
@@ -31,6 +38,83 @@ hash_type* ns_hash;
 int head;
 int tail;
 
+
+#ifndef USELIBRESOLV
+/**
+ * Implementation of do_resolve for platforms with working gethostbyaddr_r
+ */
+char* do_resolve(struct in_addr * addr) {
+    struct hostent hostbuf, *hp;
+    size_t hstbuflen = 1024;
+    char *tmphstbuf;
+    int res;
+    int herr;
+    char * ret = NULL;
+
+    /* Allocate buffer, remember to free it to avoid memory leakage.  */            
+    tmphstbuf = xmalloc (hstbuflen);
+
+    while ((res = gethostbyaddr_r ((char*)addr, sizeof(struct in_addr), AF_INET,
+                                   &hostbuf, tmphstbuf, hstbuflen,
+                                   &hp, &herr)) == ERANGE) {
+        /* Enlarge the buffer.  */
+        hstbuflen *= 2;
+        tmphstbuf = realloc (tmphstbuf, hstbuflen);
+      }
+
+    /*  Check for errors.  */
+    if (res || hp == NULL) {
+        /* failed */
+        /* Leave the unresolved IP in the hash */
+    }
+    else {
+        ret = xstrdup(hp->h_name);
+
+    }
+    xfree(tmphstbuf);
+    return ret;
+}
+
+#else
+
+/**
+ * libresolv implementation
+ */
+char* do_resolve(struct in_addr * addr) {
+  char msg[PACKETSZ];
+  char s[35];
+  int l;
+  unsigned char* a;
+  char * ret = NULL;
+
+  a = (unsigned char*)addr;
+
+  snprintf(s, 35, "%d.%d.%d.%d.in-addr.arpa.",a[3], a[2], a[1], a[0]);
+
+  l = res_search(s, C_IN, T_PTR, msg, PACKETSZ);
+  if(l != -1) {
+    ns_msg nsmsg;
+    ns_rr rr;
+    if(ns_initparse(msg, l, &nsmsg) != -1) {
+      int c;
+      int i;
+      c = ns_msg_count(nsmsg, ns_s_an);
+      for(i = 0; i < c; i++) {
+        if(ns_parserr(&nsmsg, ns_s_an, i, &rr) == 0){
+          if(ns_rr_type(rr) == T_PTR) {
+            char buf[256];
+            ns_name_uncompress(msg, msg + l, ns_rr_rdata(rr), buf, 256);
+            ret = xstrdup(buf);
+          }
+
+        }
+      }
+    }
+  }
+  return ret;
+}
+#endif
+
 void resolver_worker(void* ptr) {
     struct timespec delay;
 /*    int thread_number = *(int*)ptr;*/
@@ -45,12 +129,8 @@ void resolver_worker(void* ptr) {
 
         /* Keep resolving until the queue is empty */
         while(head != tail) {
+            char * hostname;
             struct in_addr addr = resolve_queue[tail];
-            struct hostent hostbuf, *hp;
-            size_t hstbuflen;
-            char *tmphstbuf;
-            int res;
-            int herr;
 
             /* mutex always locked at this point */
 
@@ -58,40 +138,22 @@ void resolver_worker(void* ptr) {
 
             pthread_mutex_unlock(&resolver_queue_mutex);
 
-            hstbuflen = 1024;
-            /* Allocate buffer, remember to free it to avoid memory leakage.  */            
-            tmphstbuf = xmalloc (hstbuflen);
-
-            while ((res = gethostbyaddr_r ((char*)&addr, sizeof(addr), AF_INET,
-                                           &hostbuf, tmphstbuf, hstbuflen,
-                                           &hp, &herr)) == ERANGE) {
-                /* Enlarge the buffer.  */
-                hstbuflen *= 2;
-                tmphstbuf = realloc (tmphstbuf, hstbuflen);
-              }
+            hostname = do_resolve(&addr);
 
             /*
              * Store the result in ns_hash
              */
             pthread_mutex_lock(&resolver_queue_mutex);
 
-            /*  Check for errors.  */
-            if (res || hp == NULL) {
-                /* failed */
-                /* Leave the unresolved IP in the hash */
-            }
-            else {
-                /* success */
-                char* hostname;
-                if(hash_find(ns_hash, &addr, (void**)&hostname) == HASH_STATUS_OK) {
+            if(hostname != NULL) {
+                char* old;
+                if(hash_find(ns_hash, &addr, (void**)&old) == HASH_STATUS_OK) {
                     hash_delete(ns_hash, &addr);
-                    xfree(hostname);
+                    xfree(old);
                 }
-                hostname = strdup(hp->h_name);
                 hash_insert(ns_hash, &addr, (void*)hostname);
-
             }
-            xfree(tmphstbuf);
+
         }
     }
 }