[iproute2 net-next v2 0/3] ip netconf improvements

Currently, ip netconf only shows data for ipv4 and ipv6 for dumps
and just ipv4 for device requests. Improve the user experience by
using the new kernel patch to dump all address families that have
registered. For example, if mpls_router module is loaded then mpls
values are displayed along with ipv4 and ipv6.

If the new feature is not supported (new iproute2 on older kernel)
the kernel returns the nlmsg error EOPNOTSUPP which can be trapped
and fallback to existing behavior.

v2
- fixed index conversion in patch 3 per nicholas' comment

David Ahern (3):
  netlink: Add flag to suppress print of nlmsg error
  ip netconf: Show all address families by default in dumps
  ip netconf: show all families on dev request

 include/libnetlink.h |  1 +
 ip/ipnetconf.c       | 36 +++++++++++++++++++++++++-----------
 lib/libnetlink.c     |  3 ++-
 3 files changed, 28 insertions(+), 12 deletions(-)

-- 
2.1.4

Currently, 'ip netconf' only shows ipv4 and ipv6 netconf settings. If IPv6
is not enabled, the dump ends with
    RTNETLINK answers: Operation not supported

when IPv6 request is attempted. Further, if the mpls_router module is also
loaded a separate request is needed to get MPLS settings.

To make this better going forward, use the new PF_UNSPEC dump all option
if the kernel supports it. If the kernel does not, it sets NLMSG_ERROR and
returns EOPNOTSUPP which is trapped and we fall back to the existing output
to maintain compatibility with existing kernels.

Signed-off-by: David Ahern <redacted>
---
 ip/ipnetconf.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/ip/ipnetconf.c b/ip/ipnetconf.c
index af539f5e945c..dc0851025223 100644
--- a/ip/ipnetconf.c
+++ b/ip/ipnetconf.c

@@ -19,6 +19,7 @@
 #include <sys/time.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
+#include <errno.h>
 
 #include "rt_names.h"
 #include "utils.h"

@@ -197,16 +198,26 @@ static int do_show(int argc, char **argv)
 		}
 		rtnl_listen(&rth, print_netconf, stdout);
 	} else {
+		rth.flags = RTNL_HANDLE_F_SUPPRESS_NLERR;
 dump:
 		if (rtnl_wilddump_request(&rth, filter.family, RTM_GETNETCONF) < 0) {
 			perror("Cannot send dump request");
 			exit(1);
 		}
 		if (rtnl_dump_filter(&rth, print_netconf2, stdout) < 0) {
+			/* kernel does not support netconf dump on AF_UNSPEC;
+			 * fall back to requesting by family
+			 */
+			if (errno == EOPNOTSUPP &&
+			    filter.family == AF_UNSPEC) {
+				filter.family = AF_INET;
+				goto dump;
+			}
+			perror("RTNETLINK answers");
 			fprintf(stderr, "Dump terminated\n");
 			exit(1);
 		}
-		if (preferred_family == AF_UNSPEC) {
+		if (preferred_family == AF_UNSPEC && filter.family == AF_INET) {
 			preferred_family = AF_INET6;
 			filter.family = AF_INET6;
 			goto dump;

-- 
2.1.4

Allow callers of the dump API to handle nlmsg errors (e.g., an
unsupported feature). Setting RTNL_HANDLE_F_SUPPRESS_NLERR in the
rtnl_handle avoids unnecessary messages to the users in some case.
For example,

  RTNETLINK answers: Operation not supported

when probing for support of a new feature.

Signed-off-by: David Ahern <redacted>
---
 include/libnetlink.h | 1 +
 lib/libnetlink.c     | 3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/libnetlink.h b/include/libnetlink.h
index bd0267dfcc02..c43ab0a2d9d9 100644
--- a/include/libnetlink.h
+++ b/include/libnetlink.h

@@ -21,6 +21,7 @@ struct rtnl_handle {
 	int			proto;
 	FILE		       *dump_fp;
 #define RTNL_HANDLE_F_LISTEN_ALL_NSID		0x01
+#define RTNL_HANDLE_F_SUPPRESS_NLERR		0x02
 	int			flags;
 };
 

diff --git a/lib/libnetlink.c b/lib/libnetlink.c
index 9303b6686e2c..5b75b2db4e0b 100644
--- a/lib/libnetlink.c
+++ b/lib/libnetlink.c

@@ -299,7 +299,8 @@ static void rtnl_dump_error(const struct rtnl_handle *rth,
 		     errno == EOPNOTSUPP))
 			return;
 
-		perror("RTNETLINK answers");
+		if (!(rth->flags & RTNL_HANDLE_F_SUPPRESS_NLERR))
+			perror("RTNETLINK answers");
 	}
 }
 

-- 
2.1.4

Currently specifying a device to ip netconf and it dumps only values
for IPv4. Change this to dump data for all families unless a specific
family is given.

Signed-off-by: David Ahern <redacted>
---
 ip/ipnetconf.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/ip/ipnetconf.c b/ip/ipnetconf.c
index dc0851025223..696e3dd51a1c 100644
--- a/ip/ipnetconf.c
+++ b/ip/ipnetconf.c

@@ -56,6 +56,7 @@ int print_netconf(const struct sockaddr_nl *who, struct rtnl_ctrl_data *ctrl,
 	struct netconfmsg *ncm = NLMSG_DATA(n);
 	int len = n->nlmsg_len;
 	struct rtattr *tb[NETCONFA_MAX+1];
+	int ifindex = 0;
 
 	if (n->nlmsg_type == NLMSG_ERROR)
 		return -1;

@@ -77,6 +78,12 @@ int print_netconf(const struct sockaddr_nl *who, struct rtnl_ctrl_data *ctrl,
 	parse_rtattr(tb, NETCONFA_MAX, netconf_rta(ncm),
 		     NLMSG_PAYLOAD(n, sizeof(*ncm)));
 
+	if (tb[NETCONFA_IFINDEX])
+		ifindex = rta_getattr_u32(tb[NETCONFA_IFINDEX]);
+
+	if (filter.ifindex && filter.ifindex != ifindex)
+		return 0;
+
 	switch (ncm->ncm_family) {
 	case AF_INET:
 		fprintf(fp, "ipv4 ");

@@ -93,9 +100,7 @@ int print_netconf(const struct sockaddr_nl *who, struct rtnl_ctrl_data *ctrl,
 	}
 
 	if (tb[NETCONFA_IFINDEX]) {
-		int *ifindex = (int *)rta_getattr_str(tb[NETCONFA_IFINDEX]);
-
-		switch (*ifindex) {
+		switch (ifindex) {
 		case NETCONFA_IFINDEX_ALL:
 			fprintf(fp, "all ");
 			break;

@@ -103,7 +108,7 @@ int print_netconf(const struct sockaddr_nl *who, struct rtnl_ctrl_data *ctrl,
 			fprintf(fp, "default ");
 			break;
 		default:
-			fprintf(fp, "dev %s ", ll_index_to_name(*ifindex));
+			fprintf(fp, "dev %s ", ll_index_to_name(ifindex));
 			break;
 		}
 	}

@@ -169,8 +174,6 @@ static int do_show(int argc, char **argv)
 
 	ipnetconf_reset_filter(0);
 	filter.family = preferred_family;
-	if (filter.family == AF_UNSPEC)
-		filter.family = AF_INET;
 
 	while (argc > 0) {
 		if (strcmp(*argv, "dev") == 0) {

@@ -186,11 +189,11 @@ static int do_show(int argc, char **argv)
 	}
 
 	ll_init_map(&rth);
-	if (filter.ifindex) {
+
+	if (filter.ifindex && filter.family != AF_UNSPEC) {
 		req.ncm.ncm_family = filter.family;
-		if (filter.ifindex)
-			addattr_l(&req.n, sizeof(req), NETCONFA_IFINDEX,
-				  &filter.ifindex, sizeof(filter.ifindex));
+		addattr_l(&req.n, sizeof(req), NETCONFA_IFINDEX,
+			  &filter.ifindex, sizeof(filter.ifindex));
 
 		if (rtnl_send(&rth, &req.n, req.n.nlmsg_len) < 0) {
 			perror("Can not send request");

-- 
2.1.4

Le 24/03/2017 à 03:51, David Ahern a écrit :

Currently, ip netconf only shows data for ipv4 and ipv6 for dumps
and just ipv4 for device requests. Improve the user experience by
using the new kernel patch to dump all address families that have
registered. For example, if mpls_router module is loaded then mpls
values are displayed along with ipv4 and ipv6.

If the new feature is not supported (new iproute2 on older kernel)
the kernel returns the nlmsg error EOPNOTSUPP which can be trapped
and fallback to existing behavior.

Acked-by: Nicolas Dichtel <redacted>

On 3/23/17 10:51 PM, David Ahern wrote:

Currently, ip netconf only shows data for ipv4 and ipv6 for dumps
and just ipv4 for device requests. Improve the user experience by
using the new kernel patch to dump all address families that have
registered. For example, if mpls_router module is loaded then mpls
values are displayed along with ipv4 and ipv6.

If the new feature is not supported (new iproute2 on older kernel)
the kernel returns the nlmsg error EOPNOTSUPP which can be trapped
and fallback to existing behavior.

v2
- fixed index conversion in patch 3 per nicholas' comment

David Ahern (3):
  netlink: Add flag to suppress print of nlmsg error
  ip netconf: Show all address families by default in dumps
  ip netconf: show all families on dev request

 include/libnetlink.h |  1 +
 ip/ipnetconf.c       | 36 +++++++++++++++++++++++++-----------
 lib/libnetlink.c     |  3 ++-
 3 files changed, 28 insertions(+), 12 deletions(-)

Hi Stephen: any comments? are you ok with this change?

On Tue, 4 Apr 2017 17:07:31 -0400
David Ahern [off-list ref] wrote:

On 3/23/17 10:51 PM, David Ahern wrote:

quoted

Currently, ip netconf only shows data for ipv4 and ipv6 for dumps
and just ipv4 for device requests. Improve the user experience by
using the new kernel patch to dump all address families that have
registered. For example, if mpls_router module is loaded then mpls
values are displayed along with ipv4 and ipv6.

If the new feature is not supported (new iproute2 on older kernel)
the kernel returns the nlmsg error EOPNOTSUPP which can be trapped
and fallback to existing behavior.

v2
- fixed index conversion in patch 3 per nicholas' comment

David Ahern (3):
  netlink: Add flag to suppress print of nlmsg error
  ip netconf: Show all address families by default in dumps
  ip netconf: show all families on dev request

 include/libnetlink.h |  1 +
 ip/ipnetconf.c       | 36 +++++++++++++++++++++++++-----------
 lib/libnetlink.c     |  3 ++-
 3 files changed, 28 insertions(+), 12 deletions(-)
  

Hi Stephen: any comments? are you ok with this change?

I was holding off until all the upstream commits went through. Other than
that fine.

On 4/4/17 5:39 PM, Stephen Hemminger wrote:

On Tue, 4 Apr 2017 17:07:31 -0400
David Ahern [off-list ref] wrote:

quoted

On 3/23/17 10:51 PM, David Ahern wrote:

quoted

Currently, ip netconf only shows data for ipv4 and ipv6 for dumps
and just ipv4 for device requests. Improve the user experience by
using the new kernel patch to dump all address families that have
registered. For example, if mpls_router module is loaded then mpls
values are displayed along with ipv4 and ipv6.

If the new feature is not supported (new iproute2 on older kernel)
the kernel returns the nlmsg error EOPNOTSUPP which can be trapped
and fallback to existing behavior.

v2
- fixed index conversion in patch 3 per nicholas' comment

David Ahern (3):
  netlink: Add flag to suppress print of nlmsg error
  ip netconf: Show all address families by default in dumps
  ip netconf: show all families on dev request

 include/libnetlink.h |  1 +
 ip/ipnetconf.c       | 36 +++++++++++++++++++++++++-----------
 lib/libnetlink.c     |  3 ++-
 3 files changed, 28 insertions(+), 12 deletions(-)
  

Hi Stephen: any comments? are you ok with this change?

I was holding off until all the upstream commits went through. Other than
that fine.

I'm not aware of any kernel commits that not in net-next, so I think we
good to go on the kernel side.

On Thu, 23 Mar 2017 19:51:19 -0700
David Ahern [off-list ref] wrote:

Currently, ip netconf only shows data for ipv4 and ipv6 for dumps
and just ipv4 for device requests. Improve the user experience by
using the new kernel patch to dump all address families that have
registered. For example, if mpls_router module is loaded then mpls
values are displayed along with ipv4 and ipv6.

If the new feature is not supported (new iproute2 on older kernel)
the kernel returns the nlmsg error EOPNOTSUPP which can be trapped
and fallback to existing behavior.

v2
- fixed index conversion in patch 3 per nicholas' comment

David Ahern (3):
  netlink: Add flag to suppress print of nlmsg error
  ip netconf: Show all address families by default in dumps
  ip netconf: show all families on dev request

 include/libnetlink.h |  1 +
 ip/ipnetconf.c       | 36 +++++++++++++++++++++++++-----------
 lib/libnetlink.c     |  3 ++-
 3 files changed, 28 insertions(+), 12 deletions(-)

Sure applied, just wanted to make sure there was nothing interrelated
with recent spate of changes to netlink notifications.