[PATCH iproute2-next v2] ip: link_gre6.c: Support IP6_TNL_F_ALLOW_LOCAL_REMOTE flag

For IP-in-IP tunnels, one can specify the [no]allow-localremote command
when configuring a device. Under the hood, this flips the
IP6_TNL_F_ALLOW_LOCAL_REMOTE flag on the netdevice. However, ip6gretap
and ip6erspan devices, where the flag is also relevant, are not IP-in-IP
tunnels, and thus there's no way to configure the flag on these
netdevices. Therefore introduce the command to link_gre6 as well.

The original support was introduced in commit
21440d19d957 ("ip: link_ip6tnl.c/ip6tunnel.c: Support IP6_TNL_F_ALLOW_LOCAL_REMOTE flag")

Signed-off-by: Petr Machata <redacted>
---

Notes:
    Changes from v1 to v2:
    
    - Rebase to iproute2-next

 ip/link_gre6.c        | 11 +++++++++++
 man/man8/ip-link.8.in | 14 ++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/ip/link_gre6.c b/ip/link_gre6.c
index 6c77038..e0746bc 100644
--- a/ip/link_gre6.c
+++ b/ip/link_gre6.c

@@ -48,6 +48,7 @@ static void gre_print_help(struct link_util *lu, int argc, char **argv, FILE *f)
 		"                     [ dscp inherit ]\n"
 		"                     [ dev PHYS_DEV ]\n"
 		"                     [ fwmark MARK ]\n"
+		"                     [ [no]allow-localremote ]\n"
 		"                     [ external ]\n"
 		"                     [ noencap ]\n"
 		"                     [ encap { fou | gue | none } ]\n"

@@ -346,6 +347,10 @@ get_failed:
 					invarg("invalid fwmark\n", *argv);
 				flags &= ~IP6_TNL_F_USE_ORIG_FWMARK;
 			}
+		} else if (strcmp(*argv, "allow-localremote") == 0) {
+			flags |= IP6_TNL_F_ALLOW_LOCAL_REMOTE;
+		} else if (strcmp(*argv, "noallow-localremote") == 0) {
+			flags &= ~IP6_TNL_F_ALLOW_LOCAL_REMOTE;
 		} else if (strcmp(*argv, "encaplimit") == 0) {
 			NEXT_ARG();
 			if (strcmp(*argv, "none") == 0) {

@@ -534,6 +539,12 @@ static void gre_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 	if (oflags & GRE_CSUM)
 		print_bool(PRINT_ANY, "ocsum", "ocsum ", true);
 
+	if (flags & IP6_TNL_F_ALLOW_LOCAL_REMOTE)
+		print_bool(PRINT_ANY,
+			   "ip6_tnl_f_allow_local_remote",
+			   "allow-localremote ",
+			   true);
+
 	if (flags & IP6_TNL_F_USE_ORIG_FWMARK) {
 		print_bool(PRINT_ANY,
 			   "ip6_tnl_f_use_orig_fwmark",

diff --git a/man/man8/ip-link.8.in b/man/man8/ip-link.8.in
index 481589e..5dee9fc 100644
--- a/man/man8/ip-link.8.in
+++ b/man/man8/ip-link.8.in

@@ -793,6 +793,8 @@ the following additional arguments are supported:
 ] [
 .BI "dscp inherit"
 ] [
+.BI "[no]allow-localremote"
+] [
 .BI dev " PHYS_DEV "
 ] [
 .RB external

@@ -857,6 +859,11 @@ flag is equivalent to the combination
 - specifies a fixed flowlabel.
 
 .sp
+.BI  [no]allow-localremote
+- specifies whether to allow remote endpoint to have an address configured on
+local host.
+
+.sp
 .BI  tclass " TCLASS"
 - specifies the traffic class field on
 tunneled packets, which can be specified as either a two-digit

@@ -927,6 +934,8 @@ the following additional arguments are supported:
 ] [
 .BR erspan_hwid " \fIhwid "
 ] [
+.BI "[no]allow-localremote"
+] [
 .RB external
 ]
 

@@ -965,6 +974,11 @@ traffic's source port and direction.
 is a 6-bit value for users to configure.
 
 .sp
+.BI  [no]allow-localremote
+- specifies whether to allow remote endpoint to have an address configured on
+local host.
+
+.sp
 .BR external
 - make this tunnel externally controlled (or not, which is the default).
 In the kernel, this is referred to as collect metadata mode.  This flag is

-- 
2.4.11

Petr Machata wrote:

For IP-in-IP tunnels, one can specify the [no]allow-localremote command
when configuring a device. Under the hood, this flips the
IP6_TNL_F_ALLOW_LOCAL_REMOTE flag on the netdevice. However, ip6gretap
and ip6erspan devices, where the flag is also relevant, are not IP-in-IP
tunnels, and thus there's no way to configure the flag on these
netdevices. Therefore introduce the command to link_gre6 as well.

The original support was introduced in commit
21440d19d957 ("ip: link_ip6tnl.c/ip6tunnel.c: Support IP6_TNL_F_ALLOW_LOCAL_REMOTE flag")

This would produce following checkpatch.pl error:

----------------------------------------------------------------------------------
Commit b7a2f4a74cd0 ("ip: link_gre6.c: Support
IP6_TNL_F_ALLOW_LOCAL_REMOTE flag")
----------------------------------------------------------------------------------
WARNING: Possible unwrapped commit description (prefer a maximum 75
chars per line)
#14:
21440d19d957 ("ip: link_ip6tnl.c/ip6tunnel.c: Support
IP6_TNL_F_ALLOW_LOCAL_REMOTE flag")

ERROR: Please use git commit description style 'commit <12+ chars of
sha1> ("<title line>")' - ie: 'commit 21440d19d957 ("ip:
link_ip6tnl.c/ip6tunnel.c: Support IP6_TNL_F_ALLOW_LOCAL_REMOT'
#14:
21440d19d957 ("ip: link_ip6tnl.c/ip6tunnel.c: Support
IP6_TNL_F_ALLOW_LOCAL_REMOTE flag")

You probably should address it. In general change looks good to me.

Serhey Popovych [off-list ref] writes:

Petr Machata wrote:

quoted

For IP-in-IP tunnels, one can specify the [no]allow-localremote command
when configuring a device. Under the hood, this flips the
IP6_TNL_F_ALLOW_LOCAL_REMOTE flag on the netdevice. However, ip6gretap
and ip6erspan devices, where the flag is also relevant, are not IP-in-IP
tunnels, and thus there's no way to configure the flag on these
netdevices. Therefore introduce the command to link_gre6 as well.

The original support was introduced in commit
21440d19d957 ("ip: link_ip6tnl.c/ip6tunnel.c: Support IP6_TNL_F_ALLOW_LOCAL_REMOTE flag")

This would produce following checkpatch.pl error:

----------------------------------------------------------------------------------
Commit b7a2f4a74cd0 ("ip: link_gre6.c: Support
IP6_TNL_F_ALLOW_LOCAL_REMOTE flag")
----------------------------------------------------------------------------------
WARNING: Possible unwrapped commit description (prefer a maximum 75
chars per line)
#14:
21440d19d957 ("ip: link_ip6tnl.c/ip6tunnel.c: Support
IP6_TNL_F_ALLOW_LOCAL_REMOTE flag")

ERROR: Please use git commit description style 'commit <12+ chars of
sha1> ("<title line>")' - ie: 'commit 21440d19d957 ("ip:
link_ip6tnl.c/ip6tunnel.c: Support IP6_TNL_F_ALLOW_LOCAL_REMOT'
#14:
21440d19d957 ("ip: link_ip6tnl.c/ip6tunnel.c: Support
IP6_TNL_F_ALLOW_LOCAL_REMOTE flag")

You probably should address it. In general change looks good to me.

v3 sent. The "unwrapped commit description" warning stays on the commit
reference line, but I don't see a way to shorten it without triggering
the above error again.

Thanks,
Petr