addr_resolv: add support for static hostname entries

Ping #18075

7 files changed, 29 insertions, 24 deletions

diff --git a/capinfos.c b/capinfos.c
index 626353ec72..3c7866befd 100644
--- a/capinfos.c
+++ b/capinfos.c
@@ -1135,13 +1135,13 @@ cleanup_capture_info(capture_info *cf_info)
 }
 
 static void
-count_ipv4_address(const guint addr _U_, const gchar *name _U_)
+count_ipv4_address(const guint addr _U_, const gchar *name _U_, const gboolean static_entry _U_)
 {
     num_ipv4_addresses++;
 }
 
 static void
-count_ipv6_address(const void *addrp _U_, const gchar *name _U_)
+count_ipv6_address(const void *addrp _U_, const gchar *name _U_, const gboolean static_entry _U_)
 {
     num_ipv6_addresses++;
 }
diff --git a/epan/addr_resolv.c b/epan/addr_resolv.c
index 7b46bde69f..6aad3266fe 100644
--- a/epan/addr_resolv.c
+++ b/epan/addr_resolv.c
@@ -430,10 +430,10 @@ c_ares_ghba_sync_cb(void *arg, int status, int timeouts _U_, struct hostent *he)
         for (p = he->h_addr_list; *p != NULL; p++) {
             switch(sdd->family) {
                 case AF_INET:
-                    add_ipv4_name(sdd->addr.ip4, he->h_name);
+                    add_ipv4_name(sdd->addr.ip4, he->h_name, FALSE);
                     break;
                 case AF_INET6:
-                    add_ipv6_name(&sdd->addr.ip6, he->h_name);
+                    add_ipv6_name(&sdd->addr.ip6, he->h_name, FALSE);
                     break;
                 default:
                     /* Throw an exception? */
@@ -1069,10 +1069,10 @@ c_ares_ghba_cb(void *arg, int status, int timeouts _U_, struct hostent *he) {
         for (p = he->h_addr_list; *p != NULL; p++) {
             switch(caqm->family) {
                 case AF_INET:
-                    add_ipv4_name(caqm->addr.ip4, he->h_name);
+                    add_ipv4_name(caqm->addr.ip4, he->h_name, FALSE);
                     break;
                 case AF_INET6:
-                    add_ipv6_name(&caqm->addr.ip6, he->h_name);
+                    add_ipv6_name(&caqm->addr.ip6, he->h_name, FALSE);
                     break;
                 default:
                     /* Throw an exception? */
@@ -2337,9 +2337,9 @@ read_hosts_file (const char *hostspath, gboolean store_entries)
         entry_found = TRUE;
         if (store_entries) {
             if (is_ipv6) {
-                add_ipv6_name(&host_addr.ip6_addr, cp);
+                add_ipv6_name(&host_addr.ip6_addr, cp, TRUE);
             } else {
-                add_ipv4_name(host_addr.ip4_addr, cp);
+                add_ipv4_name(host_addr.ip4_addr, cp, TRUE);
             }
         }
     }
@@ -3048,7 +3048,7 @@ get_hostname6(const ws_in6_addr *addr)
 
 /* -------------------------- */
 void
-add_ipv4_name(const guint addr, const gchar *name)
+add_ipv4_name(const guint addr, const gchar *name, gboolean static_entry)
 {
     hashipv4_t *tp;
 
@@ -3065,16 +3065,18 @@ add_ipv4_name(const guint addr, const gchar *name)
         wmem_map_insert(ipv4_hash_table, GUINT_TO_POINTER(addr), tp);
     }
 
-    if (g_ascii_strcasecmp(tp->name, name)) {
+    if (g_ascii_strcasecmp(tp->name, name) && (static_entry || !(tp->flags & STATIC_HOSTNAME))) {
         (void) g_strlcpy(tp->name, name, MAXNAMELEN);
         new_resolved_objects = TRUE;
+        if (static_entry)
+            tp->flags |= STATIC_HOSTNAME;
     }
     tp->flags |= TRIED_RESOLVE_ADDRESS|NAME_RESOLVED;
 } /* add_ipv4_name */
 
 /* -------------------------- */
 void
-add_ipv6_name(const ws_in6_addr *addrp, const gchar *name)
+add_ipv6_name(const ws_in6_addr *addrp, const gchar *name, const gboolean static_entry)
 {
     hashipv6_t *tp;
 
@@ -3095,9 +3097,11 @@ add_ipv6_name(const ws_in6_addr *addrp, const gchar *name)
         wmem_map_insert(ipv6_hash_table, addr_key, tp);
     }
 
-    if (g_ascii_strcasecmp(tp->name, name)) {
+    if (g_ascii_strcasecmp(tp->name, name) && (static_entry || !(tp->flags & STATIC_HOSTNAME))) {
         (void) g_strlcpy(tp->name, name, MAXNAMELEN);
         new_resolved_objects = TRUE;
+        if (static_entry)
+            tp->flags |= STATIC_HOSTNAME;
     }
     tp->flags |= TRIED_RESOLVE_ADDRESS|NAME_RESOLVED;
 } /* add_ipv6_name */
@@ -3106,14 +3110,14 @@ static void
 add_manually_resolved_ipv4(gpointer key, gpointer value, gpointer user_data _U_)
 {
     resolved_name_t *resolved_ipv4_entry = (resolved_name_t*)value;
-    add_ipv4_name(GPOINTER_TO_UINT(key), resolved_ipv4_entry->name);
+    add_ipv4_name(GPOINTER_TO_UINT(key), resolved_ipv4_entry->name, TRUE);
 }
 
 static void
 add_manually_resolved_ipv6(gpointer key, gpointer value, gpointer user_data _U_)
 {
     resolved_name_t *resolved_ipv6_entry = (resolved_name_t*)value;
-    add_ipv6_name((ws_in6_addr*)key, resolved_ipv6_entry->name);
+    add_ipv6_name((ws_in6_addr*)key, resolved_ipv6_entry->name, TRUE);
 }
 
 static void
diff --git a/epan/addr_resolv.h b/epan/addr_resolv.h
index f1eeb44dbc..1dc222fb40 100644
--- a/epan/addr_resolv.h
+++ b/epan/addr_resolv.h
@@ -86,6 +86,7 @@ typedef struct _resolved_name {
 #define TRIED_RESOLVE_ADDRESS    (1U<<0)  /* XXX - what does this bit *really* mean? */
 #define NAME_RESOLVED            (1U<<1)  /* the name field contains a host name, not a printable address */
 #define RESOLVED_ADDRESS_USED    (1U<<2)  /* a get_hostname* call returned the host name */
+#define STATIC_HOSTNAME          (1U<<3)  /* do not update entries from hosts file with DNS responses */
 
 #define TRIED_OR_RESOLVED_MASK   (TRIED_RESOLVE_ADDRESS | NAME_RESOLVED)
 #define USED_AND_RESOLVED_MASK   (NAME_RESOLVED | RESOLVED_ADDRESS_USED)
@@ -271,10 +272,10 @@ WS_DLL_PUBLIC char* get_hash_manuf_resolved_name(hashmanuf_t* manuf);
 
 
 /* adds a hostname/IPv4 in the hash table */
-WS_DLL_PUBLIC void add_ipv4_name(const guint addr, const gchar *name);
+WS_DLL_PUBLIC void add_ipv4_name(const guint addr, const gchar *name, const gboolean static_entry);
 
 /* adds a hostname/IPv6 in the hash table */
-WS_DLL_PUBLIC void add_ipv6_name(const ws_in6_addr *addr, const gchar *name);
+WS_DLL_PUBLIC void add_ipv6_name(const ws_in6_addr *addr, const gchar *name, const gboolean static_entry);
 
 /** Add an additional "hosts" file for IPv4 and IPv6 name resolution.
  *
diff --git a/epan/dissectors/packet-dns.c b/epan/dissectors/packet-dns.c
index 1f7cd53228..f366b1436d 100644
--- a/epan/dissectors/packet-dns.c
+++ b/epan/dissectors/packet-dns.c
@@ -2101,7 +2101,7 @@ dissect_dns_answer(tvbuff_t *tvb, int offsetx, int dns_data_offset,
           !PINFO_FD_VISITED(pinfo)) {
         guint32 addr_int;
         tvb_memcpy(tvb, &addr_int, cur_offset, sizeof(addr_int));
-        add_ipv4_name(addr_int, name);
+        add_ipv4_name(addr_int, name, FALSE);
       }
     }
     break;
@@ -2636,7 +2636,7 @@ dissect_dns_answer(tvbuff_t *tvb, int offsetx, int dns_data_offset,
           !PINFO_FD_VISITED(pinfo)) {
         ws_in6_addr  addr_in6;
         tvb_memcpy(tvb, &addr_in6, cur_offset, sizeof(addr_in6));
-        add_ipv6_name(&addr_in6, name);
+        add_ipv6_name(&addr_in6, name, FALSE);
       }
     }
     break;
diff --git a/epan/wslua/wslua_capture_info.c b/epan/wslua/wslua_capture_info.c
index cbdd7914d5..425b66f38d 100644
--- a/epan/wslua/wslua_capture_info.c
+++ b/epan/wslua/wslua_capture_info.c
@@ -190,7 +190,7 @@ static int CaptureInfo_set_hosts(lua_State* L) {
             }
             name = luaL_checklstring(L,-1,&name_len);
 
-            wth->add_new_ipv4(v4_addr, name);
+            wth->add_new_ipv4(v4_addr, name, FALSE);
 
             /* removes 'value'; keeps 'key' for next iteration */
             lua_pop(L, 1);
@@ -233,7 +233,7 @@ static int CaptureInfo_set_hosts(lua_State* L) {
             }
             name = luaL_checklstring(L,-1,&name_len);
 
-            wth->add_new_ipv6((const void *)(&v6_addr), name);
+            wth->add_new_ipv6((const void *)(&v6_addr), name, FALSE);
 
             /* removes 'value'; keeps 'key' for next iteration */
             lua_pop(L, 1);
diff --git a/wiretap/pcapng.c b/wiretap/pcapng.c
index 94c5646803..2fe0eaf0e8 100644
--- a/wiretap/pcapng.c
+++ b/wiretap/pcapng.c
@@ -2427,7 +2427,7 @@ pcapng_read_name_resolution_block(FILE_T fh, pcapng_block_header_t *bh,
                             ws_buffer_free(&nrb_rec);
                             return FALSE;      /* fail */
                         }
-                        pn->add_new_ipv4(v4_addr, namep);
+                        pn->add_new_ipv4(v4_addr, namep, FALSE);
                     }
                 }
 
@@ -2488,7 +2488,7 @@ pcapng_read_name_resolution_block(FILE_T fh, pcapng_block_header_t *bh,
                             return FALSE;      /* fail */
                         }
                         pn->add_new_ipv6(ws_buffer_start_ptr(&nrb_rec),
-                                         namep);
+                                         namep, FALSE);
                     }
                 }
 
diff --git a/wiretap/wtap.h b/wiretap/wtap.h
index 467ea4c6e8..3d927fde4c 100644
--- a/wiretap/wtap.h
+++ b/wiretap/wtap.h
@@ -1750,11 +1750,11 @@ void wtap_cleareof(wtap *wth);
  * Set callback functions to add new hostnames. Currently pcapng-only.
  * MUST match add_ipv4_name and add_ipv6_name in addr_resolv.c.
  */
-typedef void (*wtap_new_ipv4_callback_t) (const guint addr, const gchar *name);
+typedef void (*wtap_new_ipv4_callback_t) (const guint addr, const gchar *name, const gboolean static_entry);
 WS_DLL_PUBLIC
 void wtap_set_cb_new_ipv4(wtap *wth, wtap_new_ipv4_callback_t add_new_ipv4);
 
-typedef void (*wtap_new_ipv6_callback_t) (const void *addrp, const gchar *name);
+typedef void (*wtap_new_ipv6_callback_t) (const void *addrp, const gchar *name, const gboolean static_entry);
 WS_DLL_PUBLIC
 void wtap_set_cb_new_ipv6(wtap *wth, wtap_new_ipv6_callback_t add_new_ipv6);