3 files changed, 29 insertions, 0 deletions
diff --git a/sysdep/bsd/sysio.h b/sysdep/bsd/sysio.h
index c757960a..f1887fb4 100644
--- a/sysdep/bsd/sysio.h
+++ b/sysdep/bsd/sysio.h
@@ -271,3 +271,9 @@ sk_set_priority(sock *s, int prio UNUSED)
 {
   ERR_MSG("Socket priority not supported");
 }
+
+static inline int
+sk_set_freebind(sock *s)
+{
+  ERR_MSG("Freebind is not supported");
+}
diff --git a/sysdep/linux/sysio.h b/sysdep/linux/sysio.h
index e21ff487..f13eda7c 100644
--- a/sysdep/linux/sysio.h
+++ b/sysdep/linux/sysio.h
@@ -10,6 +10,10 @@
 #define IPV6_MINHOPCOUNT 73
 #endif
 
+#ifndef IPV6_FREEBIND
+#define IPV6_FREEBIND 78
+#endif
+
 #ifndef TCP_MD5SIG_EXT
 #define TCP_MD5SIG_EXT 32
 #endif
@@ -266,3 +270,18 @@ sk_set_priority(sock *s, int prio)
   return 0;
 }
 
+static inline int
+sk_set_freebind(sock *s)
+{
+  int y = 1;
+
+  if (sk_is_ipv4(s))
+    if (setsockopt(s->fd, SOL_IP, IP_FREEBIND, &y, sizeof(y)) < 0)
+      ERR("IP_FREEBIND");
+
+  if (sk_is_ipv6(s))
+    if (setsockopt(s->fd, SOL_IPV6, IPV6_FREEBIND, &y, sizeof(y)) < 0)
+      ERR("IPV6_FREEBIND");
+
+  return 0;
+}
diff --git a/sysdep/unix/io.c b/sysdep/unix/io.c
index 3d67d0a7..4fd77453 100644
--- a/sysdep/unix/io.c
+++ b/sysdep/unix/io.c
@@ -1436,6 +1436,10 @@ sk_open(sock *s)
 	if (sk_set_high_port(s) < 0)
 	  log(L_WARN "Socket error: %s%#m", s->err);
 
+    if (s->flags & SKF_FREEBIND)
+      if (sk_set_freebind(s) < 0)
+        log(L_WARN "Socket error: %s%#m", s->err);
+
     sockaddr_fill(&sa, s->af, bind_addr, s->iface, bind_port);
     if (bind(fd, &sa.sa, SA_LEN(sa)) < 0)
       ERR2("bind");