From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Mon, 22 Nov 2021 10:28:02 +0000 (+0100)
Subject: iputils: Add functions to retrieve the list of network interfaces, addresses
X-Git-Tag: auth-4.7.0-alpha1~118^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6ec09d51c4412da3edd2def5d9bce8ae4062d2e8;p=thirdparty%2Fpdns.git

iputils: Add functions to retrieve the list of network interfaces, addresses

Only tested on Linux but should work at least on FreeBSD and OpenBSD
as well.
---

diff --git a/m4/pdns_check_network_libs.m4 b/m4/pdns_check_network_libs.m4
index d8b020c875..f74311473c 100644
--- a/m4/pdns_check_network_libs.m4
+++ b/m4/pdns_check_network_libs.m4
@@ -4,4 +4,5 @@ AC_DEFUN([PDNS_CHECK_NETWORK_LIBS],[
   AC_SEARCH_LIBS([socket], [socket])
   AC_SEARCH_LIBS([gethostent], [nsl])
   AC_CHECK_FUNCS([recvmmsg sendmmsg accept4])
+  AC_CHECK_DECL(getifaddrs, [AC_DEFINE([HAVE_GETIFADDRS], [1], [Define to 1 if you have getifaddrs])], [], [#include <ifaddrs.h>])
 ])
diff --git a/pdns/iputils.cc b/pdns/iputils.cc
index 1c042289a9..67375ffb2e 100644
--- a/pdns/iputils.cc
+++ b/pdns/iputils.cc
@@ -25,6 +25,10 @@
 #include "iputils.hh"
 #include <sys/socket.h> 
 
+#if HAVE_GETIFADDRS
+#include <ifaddrs.h>
+#endif
+
 /** these functions provide a very lightweight wrapper to the Berkeley sockets API. Errors -> exceptions! */
 
 static void RuntimeError(const boost::format& fmt)
@@ -543,3 +547,56 @@ void setSocketSendBuffer(int fd, uint32_t size)
 {
   setSocketBuffer(fd, SO_SNDBUF, size);
 }
+
+std::set<std::string> getListOfNetworkInterfaces()
+{
+  std::set<std::string> result;
+#if HAVE_GETIFADDRS
+  struct ifaddrs *ifaddr;
+  if (getifaddrs(&ifaddr) == -1) {
+    return result;
+  }
+
+  for (struct ifaddrs *ifa = ifaddr; ifa != nullptr; ifa = ifa->ifa_next) {
+    if (ifa->ifa_name == nullptr) {
+      continue;
+    }
+    result.insert(ifa->ifa_name);
+  }
+
+  freeifaddrs(ifaddr);
+#endif
+  return result;
+}
+
+std::vector<ComboAddress> getListOfAddressesOfNetworkInterface(const std::string& itf)
+{
+  std::vector<ComboAddress> result;
+#if HAVE_GETIFADDRS
+  struct ifaddrs *ifaddr;
+  if (getifaddrs(&ifaddr) == -1) {
+    return result;
+  }
+
+  for (struct ifaddrs *ifa = ifaddr; ifa != nullptr; ifa = ifa->ifa_next) {
+    if (ifa->ifa_name == nullptr || strcmp(ifa->ifa_name, itf.c_str()) != 0) {
+      continue;
+    }
+    if (ifa->ifa_addr == nullptr || (ifa->ifa_addr->sa_family != AF_INET && ifa->ifa_addr->sa_family != AF_INET6)) {
+      continue;
+    }
+    ComboAddress addr;
+    try {
+      addr.setSockaddr(ifa->ifa_addr, ifa->ifa_addr->sa_family == AF_INET ? sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6));
+    }
+    catch (...) {
+      continue;
+    }
+
+    result.push_back(addr);
+  }
+
+  freeifaddrs(ifaddr);
+#endif
+  return result;
+}
diff --git a/pdns/iputils.hh b/pdns/iputils.hh
index 23b200b1a5..191e33d9fc 100644
--- a/pdns/iputils.hh
+++ b/pdns/iputils.hh
@@ -1650,6 +1650,9 @@ bool isTCPSocketUsable(int sock);
 extern template class NetmaskTree<bool>;
 ComboAddress parseIPAndPort(const std::string& input, uint16_t port);
 
+std::set<std::string> getListOfNetworkInterfaces();
+std::vector<ComboAddress> getListOfAddressesOfNetworkInterface(const std::string& itf);
+
 /* These functions throw if the value was already set to a higher value,
    or on error */
 void setSocketBuffer(int fd, int optname, uint32_t size);