From 1c26ae984a79224ce64b40dbc7239bf9721bb096 Mon Sep 17 00:00:00 2001
From: Micael Karlberg <bmk@erlang.org>
Date: Fri, 20 Jul 2018 15:14:06 +0200
Subject: [socket-nif] Add support for socket (level ip) option freebind

Added support for ip level socket option FREEBIND.

Note that there is an option available on FreeBSD called
IP_BINDANY, which seems to have similar properties (FREEBIND
is *not* available on FreeBSD). There are some restrictions
for this option though (which is not mentioned in the Linux
man page).

OTP-14831
---
 erts/emulator/nifs/common/socket_nif.c | 60 ++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

(limited to 'erts/emulator')

diff --git a/erts/emulator/nifs/common/socket_nif.c b/erts/emulator/nifs/common/socket_nif.c
index 6df2020e5e..f319f171ad 100644
--- a/erts/emulator/nifs/common/socket_nif.c
+++ b/erts/emulator/nifs/common/socket_nif.c
@@ -517,6 +517,7 @@ typedef union {
 #define SOCKET_OPT_IP_BLOCK_SOURCE            3
 #define SOCKET_OPT_IP_DROP_MEMBERSHIP         5
 #define SOCKET_OPT_IP_DROP_SOURCE_MEMBERSHIP  6
+#define SOCKET_OPT_IP_FREEBIND                7
 #define SOCKET_OPT_IP_MINTTL                  9
 #define SOCKET_OPT_IP_MTU                    11
 #define SOCKET_OPT_IP_MTU_DISCOVER           12
@@ -1086,6 +1087,11 @@ static ERL_NIF_TERM nsetopt_lvl_ip_drop_source_membership(ErlNifEnv*        env,
                                                           SocketDescriptor* descP,
                                                           ERL_NIF_TERM      eVal);
 #endif
+#if defined(IP_FREEBIND)
+static ERL_NIF_TERM nsetopt_lvl_ip_freebind(ErlNifEnv*        env,
+                                            SocketDescriptor* descP,
+                                            ERL_NIF_TERM      eVal);
+#endif
 #if defined(IP_MINTTL)
 static ERL_NIF_TERM nsetopt_lvl_ip_minttl(ErlNifEnv*        env,
                                           SocketDescriptor* descP,
@@ -1408,6 +1414,10 @@ static ERL_NIF_TERM ngetopt_lvl_sock_type(ErlNifEnv*        env,
 static ERL_NIF_TERM ngetopt_lvl_ip(ErlNifEnv*        env,
                                    SocketDescriptor* descP,
                                    int               eOpt);
+#if defined(IP_FREEBIND)
+static ERL_NIF_TERM ngetopt_lvl_ip_freebind(ErlNifEnv*        env,
+                                            SocketDescriptor* descP);
+#endif
 #if defined(IP_MINTTL)
 static ERL_NIF_TERM ngetopt_lvl_ip_minttl(ErlNifEnv*        env,
                                           SocketDescriptor* descP);
@@ -4738,6 +4748,12 @@ ERL_NIF_TERM nsetopt_lvl_ip(ErlNifEnv*        env,
         break;
 #endif
 
+#if defined(IP_FREEBIND)
+    case SOCKET_OPT_IP_FREEBIND:
+        result = nsetopt_lvl_ip_freebind(env, descP, eVal);
+        break;
+#endif
+
 #if defined(IP_MINTTL)
     case SOCKET_OPT_IP_MINTTL:
         result = nsetopt_lvl_ip_minttl(env, descP, eVal);
@@ -4936,6 +4952,26 @@ ERL_NIF_TERM nsetopt_lvl_ip_drop_source_membership(ErlNifEnv*        env,
 
 
 
+/* nsetopt_lvl_ip_freebind - Level IP FREEBIND option
+ */
+#if defined(IP_FREEBIND)
+static
+ERL_NIF_TERM nsetopt_lvl_ip_freebind(ErlNifEnv*        env,
+                                     SocketDescriptor* descP,
+                                     ERL_NIF_TERM      eVal)
+{
+#if defined(SOL_IP)
+    int level = SOL_IP;
+#else
+    int level = IPPROTO_IP;
+#endif
+
+    return nsetopt_bool_opt(env, descP, level, IP_FREEBIND, eVal);
+}
+#endif
+
+
+
 /* nsetopt_lvl_ip_minttl - Level IP MINTTL option
  */
 #if defined(IP_MINTTL)
@@ -7374,6 +7410,12 @@ ERL_NIF_TERM ngetopt_lvl_ip(ErlNifEnv*        env,
     ERL_NIF_TERM result;
 
     switch (eOpt) {
+#if defined(IP_FREEBIND)
+    case SOCKET_OPT_IP_FREEBIND:
+        result = ngetopt_lvl_ip_freebind(env, descP);
+        break;
+#endif
+
 #if defined(IP_MINTTL)
     case SOCKET_OPT_IP_MINTTL:
         result = ngetopt_lvl_ip_minttl(env, descP);
@@ -7485,6 +7527,24 @@ ERL_NIF_TERM ngetopt_lvl_ip_minttl(ErlNifEnv*        env,
 #endif
 
 
+/* ngetopt_lvl_ip_freebind - Level IP FREEBIND option
+ */
+#if defined(IP_FREEBIND)
+static
+ERL_NIF_TERM ngetopt_lvl_ip_freebind(ErlNifEnv*        env,
+                                     SocketDescriptor* descP)
+{
+#if defined(SOL_IP)
+    int level = SOL_IP;
+#else
+    int level = IPPROTO_IP;
+#endif
+
+    return ngetopt_bool_opt(env, descP, level, IP_FREEBIND);
+}
+#endif
+
+
 /* ngetopt_lvl_ip_mtu - Level IP MTU option
  */
 #if defined(IP_MTU)
-- 
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