Simplify building in-addr.arpa address string

nmap · Apr 25, 2024 · 18bedde · 18bedde
1 parent 0b79498
commit 18bedde
Showing 1 changed file with 9 additions and 19 deletions.
diff --git a/nmap_dns.cc b/nmap_dns.cc
@@ -1306,27 +1306,18 @@ std::list<std::string> get_dns_servers() {
 
 bool DNS::Factory::ipToPtr(const sockaddr_storage &ip, std::string &ptr)
 {
+ static const size_t maxlen = sizeof("0.0.1.1.2.2.3.3.4.4.5.5.6.6.7.7.8.8.9.9.a.a.b.b.c.c.d.d.e.e.f.f.ip6.arpa");
+ ptr.reserve(maxlen);
+ char tmp[INET_ADDRSTRLEN];
  switch (ip.ss_family) {
  case AF_INET:
  {
- ptr.clear();
- char ipv4_c[INET_ADDRSTRLEN];
- if(!sockaddr_storage_iptop(&ip, ipv4_c)) return false;
-
- std::string ipv4 = ipv4_c;
- std::string octet;
- std::string::const_reverse_iterator crend = ipv4.rend();
- for (std::string::const_reverse_iterator c=ipv4.rbegin(); c != crend; ++c)
- if((*c)=='.')
- {
- ptr += octet + ".";
- octet.clear();
- }
- else
- octet = (*c) + octet;
-
- ptr += octet + IPV4_PTR_DOMAIN;
-
+ const in_addr_t ipv4_addr = ((const sockaddr_in *) &ip)->sin_addr.s_addr;
+ const u8 *ipv4_c = (const u8 *)&ipv4_addr;
+ sprintf(tmp, "%d.%d.%d.%d", ipv4_c[3], ipv4_c[2], ipv4_c[1], ipv4_c[0]);
+ ptr = tmp;
+ ptr += IPV4_PTR_DOMAIN;
+ error("ipToPtr: %s => %s", inet_ntop_ez(&ip, sizeof(ip)), ptr.c_str());
  break;
  }
  case AF_INET6:
@@ -1336,7 +1327,6 @@ bool DNS::Factory::ipToPtr(const sockaddr_storage &ip, std::string &ptr)
  const u8 * ipv6 = s6.sin6_addr.s6_addr;
  for (short i=15; i>=0; --i)
  {
- char tmp[3];
  sprintf(tmp, "%02x", ipv6[i]);
  ptr += '.';
  ptr += tmp[1];