add a new getsockopt option IP_IPDEFTTL to retrieve the default ttl.

this can be used as an alternative to sysctl net.inet.ip.ttl, in
programs that use pledge().
ok reyk@, "Like this" deraadt@

diff --git a/share/man/man4/ip.4 b/share/man/man4/ip.4
index 537d6e7..72b60dc 100644 (file)
--- a/share/man/man4/ip.4
+++ b/share/man/man4/ip.4
@@ -1,4 +1,4 @@
-.\"    $OpenBSD: ip.4,v 1.36 2015/09/10 17:55:21 schwarze Exp $
+.\"    $OpenBSD: ip.4,v 1.37 2015/10/20 20:22:42 benno Exp $
 .\"    $NetBSD: ip.4,v 1.3 1994/11/30 16:22:19 jtc Exp $
 .\"
 .\" Copyright (c) 1983, 1991, 1993
@@ -30,7 +30,7 @@
 .\"
 .\"     @(#)ip.4       8.2 (Berkeley) 11/30/93
 .\"
-.Dd $Mdocdate: September 10 2015 $
+.Dd $Mdocdate: October 20 2015 $
 .Dt IP 4
 .Os
 .Sh NAME
@@ -97,8 +97,10 @@ fields in the
 .Tn IP
 header for
 .Dv SOCK_STREAM
-and
+,
 .Dv SOCK_DGRAM
+and
+.Dv SOCK_RAW
 sockets.
 For example,
 .Bd -literal -offset indent
@@ -109,6 +111,9 @@ int ttl = 60;                   /* max = 255 */
 setsockopt(s, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl));
 .Ed
 .Pp
+.Dv IP_IPDEFTTL
+can be used to retrieve the system wide default ttl.
+.Pp
 If the
 .Dv IP_RECVDSTADDR
 option is enabled on a

diff --git a/sys/netinet/in.h b/sys/netinet/in.h
index 7c206e5..adb1b30 100644 (file)
--- a/sys/netinet/in.h
+++ b/sys/netinet/in.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: in.h,v 1.114 2015/04/14 12:22:15 mikeb Exp $  */
+/*     $OpenBSD: in.h,v 1.115 2015/10/20 20:22:42 benno Exp $  */
 /*     $NetBSD: in.h,v 1.20 1996/02/13 23:41:47 christos Exp $ */
 
 /*
@@ -306,6 +306,7 @@ struct ip_opts {
 #define IP_PIPEX               34   /* bool; using PIPEX */
 #define IP_RECVRTABLE          35   /* bool; receive rdomain w/dgram */
 #define IP_IPSECFLOWINFO       36   /* bool; IPsec flow info for dgram */
+#define IP_IPDEFTTL            37   /* int; IP TTL system default */
 
 #define IP_RTABLE              0x1021  /* int; routing table, see SO_RTABLE */
 #define IP_DIVERTFL            0x1022  /* int; divert direction flag opt */

diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index 8d575b7..5e9147a 100644 (file)
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: ip_output.c,v 1.302 2015/10/19 12:10:05 mpi Exp $     */
+/*     $OpenBSD: ip_output.c,v 1.303 2015/10/20 20:22:42 benno Exp $   */
 /*     $NetBSD: ip_output.c,v 1.28 1996/02/13 23:43:07 christos Exp $  */
 
 /*
@@ -1088,6 +1088,7 @@ ip_ctloutput(int op, struct socket *so, int level, int optname,
                case IP_RECVDSTPORT:
                case IP_RECVRTABLE:
                case IP_IPSECFLOWINFO:
+               case IP_IPDEFTTL:
                        *mp = m = m_get(M_WAIT, MT_SOOPTS);
                        m->m_len = sizeof(int);
                        switch (optname) {
@@ -1104,6 +1105,10 @@ ip_ctloutput(int op, struct socket *so, int level, int optname,
                                optval = inp->inp_ip_minttl;
                                break;
 
+                       case IP_IPDEFTTL:
+                               optval = ip_defttl;
+                               break;
+
 #define        OPTBIT(bit)     (inp->inp_flags & bit ? 1 : 0)
 
                        case IP_RECVOPTS: