[iproute2-next,v2,2/3] ip: route: Add IPv6 flow label support

Commit Message

Ido Schimmel Dec. 30, 2024, 8:58 a.m. UTC

Allow specifying an IPv6 flow label when performing a route lookup.

Signed-off-by: Ido Schimmel <[e-mail]>
Reviewed-by: Guillaume Nault <[e-mail]>
---
 ip/iproute.c           | 10 +++++++++-
 man/man8/ip-route.8.in |  8 +++++++-
 2 files changed, 16 insertions(+), 2 deletions(-)

Comments

Stephen Hemminger Dec. 31, 2024, 12:49 a.m. UTC | #1

On Mon, 30 Dec 2024 10:58:09 +0200
Ido Schimmel <[e-mail]> wrote:

> @@ -2129,6 +2129,14 @@ static int iproute_get(int argc, char **argv)
>  				invarg("Invalid \"ipproto\" value\n",
>  				       *argv);
>  			addattr8(&req.n, sizeof(req), RTA_IP_PROTO, ipproto);
> +		} else if (strcmp(*argv, "flowlabel") == 0) {
> +			__be32 flowlabel;
> +
> +			NEXT_ARG();
> +			if (get_be32(&flowlabel, *argv, 0))
> +				invarg("invalid flowlabel", *argv);
> +			addattr32(&req.n, sizeof(req), RTA_FLOWLABEL,
> +				  flowlabel);
>  		} else {
>  			inet_prefix addr;
>  

What about displaying flow label with the ip route command?

Ido Schimmel Dec. 31, 2024, 7:13 a.m. UTC | #2

On Mon, Dec 30, 2024 at 04:49:58PM -0800, Stephen Hemminger wrote:
> On Mon, 30 Dec 2024 10:58:09 +0200
> Ido Schimmel <[e-mail]> wrote:
> 
> > @@ -2129,6 +2129,14 @@ static int iproute_get(int argc, char **argv)
> >  				invarg("Invalid \"ipproto\" value\n",
> >  				       *argv);
> >  			addattr8(&req.n, sizeof(req), RTA_IP_PROTO, ipproto);
> > +		} else if (strcmp(*argv, "flowlabel") == 0) {
> > +			__be32 flowlabel;
> > +
> > +			NEXT_ARG();
> > +			if (get_be32(&flowlabel, *argv, 0))
> > +				invarg("invalid flowlabel", *argv);
> > +			addattr32(&req.n, sizeof(req), RTA_FLOWLABEL,
> > +				  flowlabel);
> >  		} else {
> >  			inet_prefix addr;
> >  
> 
> What about displaying flow label with the ip route command?

The flow label is not a route attribute and it is not present in
RTM_NEWROUTE messages. It is provided as an input to the route lookup
process in RTM_GETROUTE messages.

Patch

diff --git a/ip/iproute.c b/ip/iproute.c
index 9520729e58eb..e1fe26ce05d0 100644
--- a/ip/iproute.c
+++ b/ip/iproute.c
@@ -67,7 +67,7 @@  static void usage(void)
 		"                            [ mark NUMBER ] [ vrf NAME ]\n"
 		"                            [ uid NUMBER ] [ ipproto PROTOCOL ]\n"
 		"                            [ sport NUMBER ] [ dport NUMBER ]\n"
-		"                            [ as ADDRESS ]\n"
+		"                            [ as ADDRESS ] [ flowlabel FLOWLABEL ]\n"
 		"       ip route { add | del | change | append | replace } ROUTE\n"
 		"SELECTOR := [ root PREFIX ] [ match PREFIX ] [ exact PREFIX ]\n"
 		"            [ table TABLE_ID ] [ vrf NAME ] [ proto RTPROTO ]\n"
@@ -2129,6 +2129,14 @@  static int iproute_get(int argc, char **argv)
 				invarg("Invalid \"ipproto\" value\n",
 				       *argv);
 			addattr8(&req.n, sizeof(req), RTA_IP_PROTO, ipproto);
+		} else if (strcmp(*argv, "flowlabel") == 0) {
+			__be32 flowlabel;
+
+			NEXT_ARG();
+			if (get_be32(&flowlabel, *argv, 0))
+				invarg("invalid flowlabel", *argv);
+			addattr32(&req.n, sizeof(req), RTA_FLOWLABEL,
+				  flowlabel);
 		} else {
 			inet_prefix addr;
 
diff --git a/man/man8/ip-route.8.in b/man/man8/ip-route.8.in
index 676f289a6d26..69d445ef8b5c 100644
--- a/man/man8/ip-route.8.in
+++ b/man/man8/ip-route.8.in
@@ -47,7 +47,9 @@  ip-route \- routing table management
 .B  dport
 .IR NUMBER " ] ["
 .B  as
-.IR ADDRESS " ]"
+.IR ADDRESS " ] ["
+.B  flowlabel
+.IR FLOWLABEL " ]
 
 .ti -8
 .BR "ip route" " { " add " | " del " | " change " | " append " | "\
@@ -1316,6 +1318,10 @@  was given, relookup the route with the source set to the preferred
 address received from the first lookup.
 If policy routing is used, it may be a different route.
 
+.TP
+.BI flowlabel " FLOWLABEL"
+ipv6 flow label as seen by the route lookup
+
 .P
 Note that this operation is not equivalent to
 .BR "ip route show" .