Re: [PATCH iproute2-master] bridge: fdb: Fix FDB dump with strict checking disabled

[Ivan Vecera <ivecera@redhat.com>]

----- Ido Schimmel <idosch@mellanox.com> wrote:
> While iproute2 correctly uses ifinfomsg struct as the ancillary header
> when requesting an FDB dump on old kernels, it sets the message type to
> RTM_GETLINK. This results in wrong reply being returned.
> 
> Fix this by using RTM_GETNEIGH instead.
> 
> Before:
> $ bridge fdb show brport dummy0
> Not RTM_NEWNEIGH: 00000158 00000010 00000002
> 
> After:
> $ bridge fdb show brport dummy0
> 2a:0b:41:1c:92:d3 vlan 1 master br0 permanent
> 2a:0b:41:1c:92:d3 master br0 permanent
> 33:33:00:00:00:01 self permanent
> 01:00:5e:00:00:01 self permanent
> 
> Fixes: 05880354c2cf ("bridge: fdb: Fix filtering with strict checking disabled")
> Signed-off-by: Ido Schimmel <idosch@mellanox.com>
> Reported-by: LiLiang <liali@redhat.com>
> ---
>  bridge/fdb.c         |  3 +--
>  include/libnetlink.h |  3 +++
>  lib/libnetlink.c     | 23 +++++++++++++++++++++++
>  3 files changed, 27 insertions(+), 2 deletions(-)
> 
> diff --git a/bridge/fdb.c b/bridge/fdb.c
> index f75e953a80e2..c4bf40390f42 100644
> --- a/bridge/fdb.c
> +++ b/bridge/fdb.c
> @@ -346,8 +346,7 @@ static int fdb_show(int argc, char **argv)
>  	if (rth.flags & RTNL_HANDLE_F_STRICT_CHK)
>  		rc = rtnl_neighdump_req(&rth, PF_BRIDGE, fdb_dump_filter);
>  	else
> -		rc = rtnl_linkdump_req_filter_fn(&rth, PF_BRIDGE,
> -						 fdb_linkdump_filter);
> +		rc = rtnl_fdb_linkdump_req_filter_fn(&rth, fdb_linkdump_filter);
>  	if (rc < 0) {
>  		perror("Cannot send dump request");
>  		exit(1);
> diff --git a/include/libnetlink.h b/include/libnetlink.h
> index 0854d6ad2fab..503b3ec11bb6 100644
> --- a/include/libnetlink.h
> +++ b/include/libnetlink.h
> @@ -81,6 +81,9 @@ int rtnl_linkdump_req_filter(struct rtnl_handle *rth, int fam, __u32 filt_mask)
>  int rtnl_linkdump_req_filter_fn(struct rtnl_handle *rth, int fam,
>  				req_filter_fn_t fn)
>  	__attribute__((warn_unused_result));
> +int rtnl_fdb_linkdump_req_filter_fn(struct rtnl_handle *rth,
> +				    req_filter_fn_t filter_fn)
> +	__attribute__((warn_unused_result));
>  int rtnl_statsdump_req_filter(struct rtnl_handle *rth, int fam, __u32 filt_mask)
>  	__attribute__((warn_unused_result));
>  int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req,
> diff --git a/lib/libnetlink.c b/lib/libnetlink.c
> index 110f47bcd65a..7b392862cb91 100644
> --- a/lib/libnetlink.c
> +++ b/lib/libnetlink.c
> @@ -503,6 +503,29 @@ int rtnl_linkdump_req_filter_fn(struct rtnl_handle *rth, int family,
>  	return __rtnl_linkdump_req(rth, family);
>  }
>  
> +int rtnl_fdb_linkdump_req_filter_fn(struct rtnl_handle *rth,
> +				    req_filter_fn_t filter_fn)
> +{
> +	struct {
> +		struct nlmsghdr nlh;
> +		struct ifinfomsg ifm;
> +		char buf[128];
> +	} req = {
> +		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
> +		.nlh.nlmsg_type = RTM_GETNEIGH,
> +		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
> +		.nlh.nlmsg_seq = rth->dump = ++rth->seq,
> +		.ifm.ifi_family = PF_BRIDGE,
> +	};
> +	int err;
> +
> +	err = filter_fn(&req.nlh, sizeof(req));
> +	if (err)
> +		return err;
> +
> +	return send(rth->fd, &req, sizeof(req), 0);
> +}
> +
>  int rtnl_statsdump_req_filter(struct rtnl_handle *rth, int fam, __u32 filt_mask)
>  {
>  	struct {
> -- 
> 2.20.1
> 

Acked-by: Ivan Vecera <ivecera@redhat.com>