From 2151895b4eb4cb3172ba7597477fd83eb85b444a Mon Sep 17 00:00:00 2001
From: Micael Karlberg <bmk@erlang.org>
Date: Thu, 12 Jul 2018 17:30:59 +0200
Subject: [socket-nif] Add support for socket (level ip) option minttl

Added support for the IP option MINTTL.

OTP-14831
---
 erts/emulator/nifs/common/socket_nif.c |  60 +++++++++++++++++++++++++++++++++
 erts/preloaded/ebin/socket.beam        | Bin 45720 -> 45756 bytes
 erts/preloaded/src/socket.erl          |   8 +++--
 3 files changed, 65 insertions(+), 3 deletions(-)

diff --git a/erts/emulator/nifs/common/socket_nif.c b/erts/emulator/nifs/common/socket_nif.c
index a851dc94b4..37bb307e2b 100644
--- a/erts/emulator/nifs/common/socket_nif.c
+++ b/erts/emulator/nifs/common/socket_nif.c
@@ -367,6 +367,7 @@ 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_MINTTL                  9
 #define SOCKET_OPT_IP_MTU                    11
 #define SOCKET_OPT_IP_MTU_DISCOVER           12
 #define SOCKET_OPT_IP_MULTICAST_ALL          13
@@ -887,6 +888,11 @@ static ERL_NIF_TERM nsetopt_lvl_ip_drop_source_membership(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,
+                                          ERL_NIF_TERM      eVal);
+#endif
 #if defined(IP_MTU_DISCOVER)
 static ERL_NIF_TERM nsetopt_lvl_ip_mtu_discover(ErlNifEnv*        env,
                                                 SocketDescriptor* descP,
@@ -1113,6 +1119,10 @@ 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_MINTTL)
+static ERL_NIF_TERM ngetopt_lvl_ip_minttl(ErlNifEnv*        env,
+                                          SocketDescriptor* descP);
+#endif
 #if defined(IP_MTU)
 static ERL_NIF_TERM ngetopt_lvl_ip_mtu(ErlNifEnv*        env,
                                        SocketDescriptor* descP);
@@ -4129,6 +4139,12 @@ ERL_NIF_TERM nsetopt_lvl_ip(ErlNifEnv*        env,
         break;
 #endif
 
+#if defined(IP_MINTTL)
+    case SOCKET_OPT_IP_MINTTL:
+        result = nsetopt_lvl_ip_minttl(env, descP, eVal);
+        break;
+#endif
+
 #if defined(IP_MTU_DISCOVER)
     case SOCKET_OPT_IP_MTU_DISCOVER:
         result = nsetopt_lvl_ip_mtu_discover(env, descP, eVal);
@@ -4321,6 +4337,26 @@ ERL_NIF_TERM nsetopt_lvl_ip_drop_source_membership(ErlNifEnv*        env,
 
 
 
+/* nsetopt_lvl_ip_minttl - Level IP MINTTL option
+ */
+#if defined(IP_MINTTL)
+static
+ERL_NIF_TERM nsetopt_lvl_ip_minttl(ErlNifEnv*        env,
+                                   SocketDescriptor* descP,
+                                   ERL_NIF_TERM      eVal)
+{
+#if defined(SOL_IP)
+    int level = SOL_IP;
+#else
+    int level = IPPROTO_IP;
+#endif
+
+    return nsetopt_int_opt(env, descP, level, IP_MINTTL, eVal);
+}
+#endif
+
+
+
 /* nsetopt_lvl_ip_mtu_discover - Level IP MTU_DISCOVER option
  *
  * The value is an atom of the type ip_pmtudisc().
@@ -5883,6 +5919,12 @@ ERL_NIF_TERM ngetopt_lvl_ip(ErlNifEnv*        env,
     ERL_NIF_TERM result;
 
     switch (eOpt) {
+#if defined(IP_MINTTL)
+    case SOCKET_OPT_IP_MINTTL:
+        result = ngetopt_lvl_ip_minttl(env, descP);
+        break;
+#endif
+
 #if defined(IP_MTU)
     case SOCKET_OPT_IP_MTU:
         result = ngetopt_lvl_ip_mtu(env, descP);
@@ -5970,6 +6012,24 @@ ERL_NIF_TERM ngetopt_lvl_ip(ErlNifEnv*        env,
 }
 
 
+/* ngetopt_lvl_ip_minttl - Level IP MINTTL option
+ */
+#if defined(IP_MINTTL)
+static
+ERL_NIF_TERM ngetopt_lvl_ip_minttl(ErlNifEnv*        env,
+                                   SocketDescriptor* descP)
+{
+#if defined(SOL_IP)
+    int level = SOL_IP;
+#else
+    int level = IPPROTO_IP;
+#endif
+
+    return ngetopt_int_opt(env, descP, level, IP_MINTTL);
+}
+#endif
+
+
 /* ngetopt_lvl_ip_mtu - Level IP MTU option
  */
 #if defined(IP_MTU)
diff --git a/erts/preloaded/ebin/socket.beam b/erts/preloaded/ebin/socket.beam
index 57a32cfbad..fd19efd516 100644
Binary files a/erts/preloaded/ebin/socket.beam and b/erts/preloaded/ebin/socket.beam differ
diff --git a/erts/preloaded/src/socket.erl b/erts/preloaded/src/socket.erl
index f70c45b42e..c8238e9a1a 100644
--- a/erts/preloaded/src/socket.erl
+++ b/erts/preloaded/src/socket.erl
@@ -531,7 +531,7 @@
 -define(SOCKET_OPT_IP_DROP_SOURCE_MEMBERSHIP, 6).
 %% -define(SOCKET_OPT_IP_FREEBIND,               7).
 %% -define(SOCKET_OPT_IP_HDRINCL,                8).
-%% -define(SOCKET_OPT_IP_MINTTL,                 9).
+-define(SOCKET_OPT_IP_MINTTL,                 9).
 %% -define(SOCKET_OPT_IP_MSFILTER,              10).
 -define(SOCKET_OPT_IP_MTU,                   11).
 -define(SOCKET_OPT_IP_MTU_DISCOVER,          12).
@@ -2014,6 +2014,8 @@ enc_setopt_value(ip, drop_source_membership, #{multiaddr  := MA,
        (is_tuple(IF) andalso (size(IF) =:= 4)) andalso
        (is_tuple(SA) andalso (size(SA) =:= 4)) ->
     V;
+enc_setopt_value(ip, minttl, V, _D, _T, _P) when is_integer(V) ->
+    V;
 enc_setopt_value(ip, mtu_discover, V, _D, _T, _P)
   when (V =:= want)  orelse
        (V =:= dont)  orelse
@@ -2329,8 +2331,8 @@ enc_sockopt_key(ip = L, free_bind = Opt, _Dir, _D, _T, _P) ->
 enc_sockopt_key(ip = L, hdrincl = Opt, _Dir, _D, raw = _T, _P) ->
     not_supported({L, Opt});
 %% FreeBSD only?
-enc_sockopt_key(ip = L, minttl = Opt, _Dir, _D, raw = _T, _P) ->
-    not_supported({L, Opt});
+enc_sockopt_key(ip = _L, minttl = _Opt, _Dir, _D, raw = _T, _P) ->
+    ?SOCKET_OPT_IP_MINTTL;
 enc_sockopt_key(ip = L, msfilter = Opt, _Dir, _D, _T, _P) ->
     not_supported({L, Opt});
 enc_sockopt_key(ip = _L, mtu = _Opt, get = _Dir, _D, _T, _P) ->
-- 
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