Patchwork [net-next,1/2] decnet: Parse netlink attributes on our own

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Submitter Thomas Graf
Date March 21, 2013, 5:45 p.m.
Message ID <5b888618a6aebfebf496c91482794a606b3bb094.1363885020.git.tgraf@suug.ch>
Download mbox | patch
Permalink /patch/229784/
State Accepted
Delegated to: David Miller
Headers show

Comments

Thomas Graf - March 21, 2013, 5:45 p.m.
decnet is the only subsystem left that is relying on the global
netlink attribute buffer rta_buf. It's horrible design and we
want to get rid of it.

This converts all of decnet to do implicit attribute parsing. It
also gets rid of the error prone struct dn_kern_rta.

Yes, the fib_magic() stuff is not pretty.

It's compiled tested but I need someone with appropriate hardware
to test the patch since I don't have access to it.

Cc: linux-decnet-user@lists.sourceforge.net
Signed-off-by: Thomas Graf <tgraf@suug.ch>
---
 include/net/dn_fib.h  |  28 ++-----
 net/decnet/dn_fib.c   | 211 +++++++++++++++++++++++++++-----------------------
 net/decnet/dn_route.c |  27 ++++---
 net/decnet/dn_table.c |  42 +++++-----
 4 files changed, 160 insertions(+), 148 deletions(-)
Steven Whitehouse - March 21, 2013, 6:04 p.m.
Hi,

On Thu, 2013-03-21 at 18:45 +0100, Thomas Graf wrote:
> decnet is the only subsystem left that is relying on the global
> netlink attribute buffer rta_buf. It's horrible design and we
> want to get rid of it.
> 
> This converts all of decnet to do implicit attribute parsing. It
> also gets rid of the error prone struct dn_kern_rta.
> 
> Yes, the fib_magic() stuff is not pretty.
> 
> It's compiled tested but I need someone with appropriate hardware
> to test the patch since I don't have access to it.
> 

You shouldn't need any special hardware to test this. A copy of iproute2
should be enough as you should be able to use that to create an
interface or two and a route between them, etc. Although DECnet routing
works in a different way to ip routing, the Linux implementation tries
to stick fairly closely to the ip way of doing things whenever it can in
order to share infrastructure. Now that ip has diverged a fair bit over
time that isn't quite as true as it was, but there shouldn't be anything
too surprising in there.

If you want to actually pass traffic, then you'll have to set the MAC
address of your ethernet card and use the tools that Chrissie wrote to
do that.

I took a quick look at the patches and I can't spot anything obviously
wrong, but then it is a long time since I last seriously looked at it,
so I could easily have missed something,

Steve.


> Cc: linux-decnet-user@lists.sourceforge.net
> Signed-off-by: Thomas Graf <tgraf@suug.ch>
> ---
>  include/net/dn_fib.h  |  28 ++-----
>  net/decnet/dn_fib.c   | 211 +++++++++++++++++++++++++++-----------------------
>  net/decnet/dn_route.c |  27 ++++---
>  net/decnet/dn_table.c |  42 +++++-----
>  4 files changed, 160 insertions(+), 148 deletions(-)
> 
> diff --git a/include/net/dn_fib.h b/include/net/dn_fib.h
> index 1ee9d4b..74004af 100644
> --- a/include/net/dn_fib.h
> +++ b/include/net/dn_fib.h
> @@ -1,24 +1,9 @@
>  #ifndef _NET_DN_FIB_H
>  #define _NET_DN_FIB_H
>  
> -/* WARNING: The ordering of these elements must match ordering
> - *          of RTA_* rtnetlink attribute numbers.
> - */
> -struct dn_kern_rta {
> -        void            *rta_dst;
> -        void            *rta_src;
> -        int             *rta_iif;
> -        int             *rta_oif;
> -        void            *rta_gw;
> -        u32             *rta_priority;
> -        void            *rta_prefsrc;
> -        struct rtattr   *rta_mx;
> -        struct rtattr   *rta_mp;
> -        unsigned char   *rta_protoinfo;
> -        u32             *rta_flow;
> -        struct rta_cacheinfo *rta_ci;
> -	struct rta_session *rta_sess;
> -};
> +#include <linux/netlink.h>
> +
> +extern const struct nla_policy rtm_dn_policy[];
>  
>  struct dn_fib_res {
>  	struct fib_rule *r;
> @@ -93,10 +78,10 @@ struct dn_fib_table {
>  	u32 n;
>  
>  	int (*insert)(struct dn_fib_table *t, struct rtmsg *r, 
> -			struct dn_kern_rta *rta, struct nlmsghdr *n, 
> +			struct nlattr *attrs[], struct nlmsghdr *n,
>  			struct netlink_skb_parms *req);
>  	int (*delete)(struct dn_fib_table *t, struct rtmsg *r,
> -			struct dn_kern_rta *rta, struct nlmsghdr *n,
> +			struct nlattr *attrs[], struct nlmsghdr *n,
>  			struct netlink_skb_parms *req);
>  	int (*lookup)(struct dn_fib_table *t, const struct flowidn *fld,
>  			struct dn_fib_res *res);
> @@ -116,13 +101,12 @@ extern void dn_fib_cleanup(void);
>  extern int dn_fib_ioctl(struct socket *sock, unsigned int cmd, 
>  			unsigned long arg);
>  extern struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, 
> -				struct dn_kern_rta *rta, 
> +				struct nlattr *attrs[],
>  				const struct nlmsghdr *nlh, int *errp);
>  extern int dn_fib_semantic_match(int type, struct dn_fib_info *fi, 
>  			const struct flowidn *fld,
>  			struct dn_fib_res *res);
>  extern void dn_fib_release_info(struct dn_fib_info *fi);
> -extern __le16 dn_fib_get_attr16(struct rtattr *attr, int attrlen, int type);
>  extern void dn_fib_flush(void);
>  extern void dn_fib_select_multipath(const struct flowidn *fld,
>  					struct dn_fib_res *res);
> diff --git a/net/decnet/dn_fib.c b/net/decnet/dn_fib.c
> index e36614e..42a8048 100644
> --- a/net/decnet/dn_fib.c
> +++ b/net/decnet/dn_fib.c
> @@ -145,22 +145,10 @@ static inline struct dn_fib_info *dn_fib_find_info(const struct dn_fib_info *nfi
>  	return NULL;
>  }
>  
> -__le16 dn_fib_get_attr16(struct rtattr *attr, int attrlen, int type)
> +static int dn_fib_count_nhs(const struct nlattr *attr)
>  {
> -	while(RTA_OK(attr,attrlen)) {
> -		if (attr->rta_type == type)
> -			return *(__le16*)RTA_DATA(attr);
> -		attr = RTA_NEXT(attr, attrlen);
> -	}
> -
> -	return 0;
> -}
> -
> -static int dn_fib_count_nhs(struct rtattr *rta)
> -{
> -	int nhs = 0;
> -	struct rtnexthop *nhp = RTA_DATA(rta);
> -	int nhlen = RTA_PAYLOAD(rta);
> +	struct rtnexthop *nhp = nla_data(attr);
> +	int nhs = 0, nhlen = nla_len(attr);
>  
>  	while(nhlen >= (int)sizeof(struct rtnexthop)) {
>  		if ((nhlen -= nhp->rtnh_len) < 0)
> @@ -172,10 +160,11 @@ static int dn_fib_count_nhs(struct rtattr *rta)
>  	return nhs;
>  }
>  
> -static int dn_fib_get_nhs(struct dn_fib_info *fi, const struct rtattr *rta, const struct rtmsg *r)
> +static int dn_fib_get_nhs(struct dn_fib_info *fi, const struct nlattr *attr,
> +			  const struct rtmsg *r)
>  {
> -	struct rtnexthop *nhp = RTA_DATA(rta);
> -	int nhlen = RTA_PAYLOAD(rta);
> +	struct rtnexthop *nhp = nla_data(attr);
> +	int nhlen = nla_len(attr);
>  
>  	change_nexthops(fi) {
>  		int attrlen = nhlen - sizeof(struct rtnexthop);
> @@ -187,7 +176,10 @@ static int dn_fib_get_nhs(struct dn_fib_info *fi, const struct rtattr *rta, cons
>  		nh->nh_weight = nhp->rtnh_hops + 1;
>  
>  		if (attrlen) {
> -			nh->nh_gw = dn_fib_get_attr16(RTNH_DATA(nhp), attrlen, RTA_GATEWAY);
> +			struct nlattr *gw_attr;
> +
> +			gw_attr = nla_find((struct nlattr *) (nhp + 1), attrlen, RTA_GATEWAY);
> +			nh->nh_gw = gw_attr ? nla_get_le16(gw_attr) : 0;
>  		}
>  		nhp = RTNH_NEXT(nhp);
>  	} endfor_nexthops(fi);
> @@ -268,7 +260,8 @@ out:
>  }
>  
> 
> -struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct dn_kern_rta *rta, const struct nlmsghdr *nlh, int *errp)
> +struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct nlattr *attrs[],
> +				       const struct nlmsghdr *nlh, int *errp)
>  {
>  	int err;
>  	struct dn_fib_info *fi = NULL;
> @@ -281,11 +274,9 @@ struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct dn_kern_rta
>  	if (dn_fib_props[r->rtm_type].scope > r->rtm_scope)
>  		goto err_inval;
>  
> -	if (rta->rta_mp) {
> -		nhs = dn_fib_count_nhs(rta->rta_mp);
> -		if (nhs == 0)
> -			goto err_inval;
> -	}
> +	if (attrs[RTA_MULTIPATH] &&
> +	    (nhs = dn_fib_count_nhs(attrs[RTA_MULTIPATH])) == 0)
> +		goto err_inval;
>  
>  	fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct dn_fib_nh), GFP_KERNEL);
>  	err = -ENOBUFS;
> @@ -295,53 +286,65 @@ struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct dn_kern_rta
>  	fi->fib_protocol = r->rtm_protocol;
>  	fi->fib_nhs = nhs;
>  	fi->fib_flags = r->rtm_flags;
> -	if (rta->rta_priority)
> -		fi->fib_priority = *rta->rta_priority;
> -	if (rta->rta_mx) {
> -		int attrlen = RTA_PAYLOAD(rta->rta_mx);
> -		struct rtattr *attr = RTA_DATA(rta->rta_mx);
>  
> -		while(RTA_OK(attr, attrlen)) {
> -			unsigned int flavour = attr->rta_type;
> +	if (attrs[RTA_PRIORITY])
> +		fi->fib_priority = nla_get_u32(attrs[RTA_PRIORITY]);
> +
> +	if (attrs[RTA_METRICS]) {
> +		struct nlattr *attr;
> +		int rem;
>  
> -			if (flavour) {
> -				if (flavour > RTAX_MAX)
> +		nla_for_each_nested(attr, attrs[RTA_METRICS], rem) {
> +			int type = nla_type(attr);
> +
> +			if (type) {
> +				if (type > RTAX_MAX || nla_len(attr) < 4)
>  					goto err_inval;
> -				fi->fib_metrics[flavour-1] = *(unsigned int *)RTA_DATA(attr);
> +
> +				fi->fib_metrics[type-1] = nla_get_u32(attr);
>  			}
> -			attr = RTA_NEXT(attr, attrlen);
>  		}
>  	}
> -	if (rta->rta_prefsrc)
> -		memcpy(&fi->fib_prefsrc, rta->rta_prefsrc, 2);
>  
> -	if (rta->rta_mp) {
> -		if ((err = dn_fib_get_nhs(fi, rta->rta_mp, r)) != 0)
> +	if (attrs[RTA_PREFSRC])
> +		fi->fib_prefsrc = nla_get_le16(attrs[RTA_PREFSRC]);
> +
> +	if (attrs[RTA_MULTIPATH]) {
> +		if ((err = dn_fib_get_nhs(fi, attrs[RTA_MULTIPATH], r)) != 0)
>  			goto failure;
> -		if (rta->rta_oif && fi->fib_nh->nh_oif != *rta->rta_oif)
> +
> +		if (attrs[RTA_OIF] &&
> +		    fi->fib_nh->nh_oif != nla_get_u32(attrs[RTA_OIF]))
>  			goto err_inval;
> -		if (rta->rta_gw && memcmp(&fi->fib_nh->nh_gw, rta->rta_gw, 2))
> +
> +		if (attrs[RTA_GATEWAY] &&
> +		    fi->fib_nh->nh_gw != nla_get_le16(attrs[RTA_GATEWAY]))
>  			goto err_inval;
>  	} else {
>  		struct dn_fib_nh *nh = fi->fib_nh;
> -		if (rta->rta_oif)
> -			nh->nh_oif = *rta->rta_oif;
> -		if (rta->rta_gw)
> -			memcpy(&nh->nh_gw, rta->rta_gw, 2);
> +
> +		if (attrs[RTA_OIF])
> +			nh->nh_oif = nla_get_u32(attrs[RTA_OIF]);
> +
> +		if (attrs[RTA_GATEWAY])
> +			nh->nh_gw = nla_get_le16(attrs[RTA_GATEWAY]);
> +
>  		nh->nh_flags = r->rtm_flags;
>  		nh->nh_weight = 1;
>  	}
>  
>  	if (r->rtm_type == RTN_NAT) {
> -		if (rta->rta_gw == NULL || nhs != 1 || rta->rta_oif)
> +		if (!attrs[RTA_GATEWAY] || nhs != 1 || attrs[RTA_OIF])
>  			goto err_inval;
> -		memcpy(&fi->fib_nh->nh_gw, rta->rta_gw, 2);
> +
> +		fi->fib_nh->nh_gw = nla_get_le16(attrs[RTA_GATEWAY]);
>  		goto link_it;
>  	}
>  
>  	if (dn_fib_props[r->rtm_type].error) {
> -		if (rta->rta_gw || rta->rta_oif || rta->rta_mp)
> +		if (attrs[RTA_GATEWAY] || attrs[RTA_OIF] || attrs[RTA_MULTIPATH])
>  			goto err_inval;
> +
>  		goto link_it;
>  	}
>  
> @@ -367,8 +370,8 @@ struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct dn_kern_rta
>  	}
>  
>  	if (fi->fib_prefsrc) {
> -		if (r->rtm_type != RTN_LOCAL || rta->rta_dst == NULL ||
> -		    memcmp(&fi->fib_prefsrc, rta->rta_dst, 2))
> +		if (r->rtm_type != RTN_LOCAL || !attrs[RTA_DST] ||
> +		    fi->fib_prefsrc != nla_get_le16(attrs[RTA_DST]))
>  			if (dnet_addr_type(fi->fib_prefsrc) != RTN_LOCAL)
>  				goto err_inval;
>  	}
> @@ -486,29 +489,24 @@ void dn_fib_select_multipath(const struct flowidn *fld, struct dn_fib_res *res)
>  	spin_unlock_bh(&dn_fib_multipath_lock);
>  }
>  
> +const struct nla_policy rtm_dn_policy[RTA_MAX + 1] = {
> +	[RTA_DST]		= { .type = NLA_U16 },
> +	[RTA_SRC]		= { .type = NLA_U16 },
> +	[RTA_IIF]		= { .type = NLA_U32 },
> +	[RTA_OIF]		= { .type = NLA_U32 },
> +	[RTA_GATEWAY]		= { .type = NLA_U16 },
> +	[RTA_PRIORITY]		= { .type = NLA_U32 },
> +	[RTA_PREFSRC]		= { .type = NLA_U16 },
> +	[RTA_METRICS]		= { .type = NLA_NESTED },
> +	[RTA_MULTIPATH]		= { .type = NLA_NESTED },
> +	[RTA_TABLE]		= { .type = NLA_U32 },
> +	[RTA_MARK]		= { .type = NLA_U32 },
> +};
>  
> -static int dn_fib_check_attr(struct rtmsg *r, struct rtattr **rta)
> -{
> -	int i;
> -
> -	for(i = 1; i <= RTA_MAX; i++) {
> -		struct rtattr *attr = rta[i-1];
> -		if (attr) {
> -			if (RTA_PAYLOAD(attr) < 4 && RTA_PAYLOAD(attr) != 2)
> -				return -EINVAL;
> -			if (i != RTA_MULTIPATH && i != RTA_METRICS &&
> -			    i != RTA_TABLE)
> -				rta[i-1] = (struct rtattr *)RTA_DATA(attr);
> -		}
> -	}
> -
> -	return 0;
> -}
> -
> -static inline u32 rtm_get_table(struct rtattr **rta, u8 table)
> +static inline u32 rtm_get_table(struct nlattr *attrs[], u8 table)
>  {
> -	if (rta[RTA_TABLE - 1])
> -		table = nla_get_u32((struct nlattr *) rta[RTA_TABLE - 1]);
> +	if (attrs[RTA_TABLE])
> +		table = nla_get_u32(attrs[RTA_TABLE]);
>  
>  	return table;
>  }
> @@ -517,8 +515,9 @@ static int dn_fib_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *
>  {
>  	struct net *net = sock_net(skb->sk);
>  	struct dn_fib_table *tb;
> -	struct rtattr **rta = arg;
> -	struct rtmsg *r = NLMSG_DATA(nlh);
> +	struct rtmsg *r = nlmsg_data(nlh);
> +	struct nlattr *attrs[RTA_MAX+1];
> +	int err;
>  
>  	if (!capable(CAP_NET_ADMIN))
>  		return -EPERM;
> @@ -526,22 +525,24 @@ static int dn_fib_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *
>  	if (!net_eq(net, &init_net))
>  		return -EINVAL;
>  
> -	if (dn_fib_check_attr(r, rta))
> -		return -EINVAL;
> +	err = nlmsg_parse(nlh, sizeof(*r), attrs, RTA_MAX, rtm_dn_policy);
> +	if (err < 0)
> +		return err;
>  
> -	tb = dn_fib_get_table(rtm_get_table(rta, r->rtm_table), 0);
> -	if (tb)
> -		return tb->delete(tb, r, (struct dn_kern_rta *)rta, nlh, &NETLINK_CB(skb));
> +	tb = dn_fib_get_table(rtm_get_table(attrs, r->rtm_table), 0);
> +	if (!tb)
> +		return -ESRCH;
>  
> -	return -ESRCH;
> +	return tb->delete(tb, r, attrs, nlh, &NETLINK_CB(skb));
>  }
>  
>  static int dn_fib_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
>  {
>  	struct net *net = sock_net(skb->sk);
>  	struct dn_fib_table *tb;
> -	struct rtattr **rta = arg;
> -	struct rtmsg *r = NLMSG_DATA(nlh);
> +	struct rtmsg *r = nlmsg_data(nlh);
> +	struct nlattr *attrs[RTA_MAX+1];
> +	int err;
>  
>  	if (!capable(CAP_NET_ADMIN))
>  		return -EPERM;
> @@ -549,14 +550,15 @@ static int dn_fib_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *
>  	if (!net_eq(net, &init_net))
>  		return -EINVAL;
>  
> -	if (dn_fib_check_attr(r, rta))
> -		return -EINVAL;
> +	err = nlmsg_parse(nlh, sizeof(*r), attrs, RTA_MAX, rtm_dn_policy);
> +	if (err < 0)
> +		return err;
>  
> -	tb = dn_fib_get_table(rtm_get_table(rta, r->rtm_table), 1);
> -	if (tb)
> -		return tb->insert(tb, r, (struct dn_kern_rta *)rta, nlh, &NETLINK_CB(skb));
> +	tb = dn_fib_get_table(rtm_get_table(attrs, r->rtm_table), 1);
> +	if (!tb)
> +		return -ENOBUFS;
>  
> -	return -ENOBUFS;
> +	return tb->insert(tb, r, attrs, nlh, &NETLINK_CB(skb));
>  }
>  
>  static void fib_magic(int cmd, int type, __le16 dst, int dst_len, struct dn_ifaddr *ifa)
> @@ -566,10 +568,31 @@ static void fib_magic(int cmd, int type, __le16 dst, int dst_len, struct dn_ifad
>  		struct nlmsghdr nlh;
>  		struct rtmsg rtm;
>  	} req;
> -	struct dn_kern_rta rta;
> +	struct {
> +		struct nlattr hdr;
> +		__le16 dst;
> +	} dst_attr = {
> +		.dst = dst,
> +	};
> +	struct {
> +		struct nlattr hdr;
> +		__le16 prefsrc;
> +	} prefsrc_attr = {
> +		.prefsrc = ifa->ifa_local,
> +	};
> +	struct {
> +		struct nlattr hdr;
> +		u32 oif;
> +	} oif_attr = {
> +		.oif = ifa->ifa_dev->dev->ifindex,
> +	};
> +	struct nlattr *attrs[RTA_MAX+1] = {
> +		[RTA_DST] = (struct nlattr *) &dst_attr,
> +		[RTA_PREFSRC] = (struct nlattr * ) &prefsrc_attr,
> +		[RTA_OIF] = (struct nlattr *) &oif_attr,
> +	};
>  
>  	memset(&req.rtm, 0, sizeof(req.rtm));
> -	memset(&rta, 0, sizeof(rta));
>  
>  	if (type == RTN_UNICAST)
>  		tb = dn_fib_get_table(RT_MIN_TABLE, 1);
> @@ -591,14 +614,10 @@ static void fib_magic(int cmd, int type, __le16 dst, int dst_len, struct dn_ifad
>  	req.rtm.rtm_scope = (type != RTN_LOCAL ? RT_SCOPE_LINK : RT_SCOPE_HOST);
>  	req.rtm.rtm_type = type;
>  
> -	rta.rta_dst = &dst;
> -	rta.rta_prefsrc = &ifa->ifa_local;
> -	rta.rta_oif = &ifa->ifa_dev->dev->ifindex;
> -
>  	if (cmd == RTM_NEWROUTE)
> -		tb->insert(tb, &req.rtm, &rta, &req.nlh, NULL);
> +		tb->insert(tb, &req.rtm, attrs, &req.nlh, NULL);
>  	else
> -		tb->delete(tb, &req.rtm, &rta, &req.nlh, NULL);
> +		tb->delete(tb, &req.rtm, attrs, &req.nlh, NULL);
>  }
>  
>  static void dn_fib_add_ifaddr(struct dn_ifaddr *ifa)
> diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
> index 5ac0e15..b4b3508 100644
> --- a/net/decnet/dn_route.c
> +++ b/net/decnet/dn_route.c
> @@ -1619,17 +1619,21 @@ errout:
>  static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
>  {
>  	struct net *net = sock_net(in_skb->sk);
> -	struct rtattr **rta = arg;
>  	struct rtmsg *rtm = nlmsg_data(nlh);
>  	struct dn_route *rt = NULL;
>  	struct dn_skb_cb *cb;
>  	int err;
>  	struct sk_buff *skb;
>  	struct flowidn fld;
> +	struct nlattr *tb[RTA_MAX+1];
>  
>  	if (!net_eq(net, &init_net))
>  		return -EINVAL;
>  
> +	err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_dn_policy);
> +	if (err < 0)
> +		return err;
> +
>  	memset(&fld, 0, sizeof(fld));
>  	fld.flowidn_proto = DNPROTO_NSP;
>  
> @@ -1639,12 +1643,14 @@ static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void
>  	skb_reset_mac_header(skb);
>  	cb = DN_SKB_CB(skb);
>  
> -	if (rta[RTA_SRC-1])
> -		memcpy(&fld.saddr, RTA_DATA(rta[RTA_SRC-1]), 2);
> -	if (rta[RTA_DST-1])
> -		memcpy(&fld.daddr, RTA_DATA(rta[RTA_DST-1]), 2);
> -	if (rta[RTA_IIF-1])
> -		memcpy(&fld.flowidn_iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
> +	if (tb[RTA_SRC])
> +		fld.saddr = nla_get_le16(tb[RTA_SRC]);
> +
> +	if (tb[RTA_DST])
> +		fld.daddr = nla_get_le16(tb[RTA_DST]);
> +
> +	if (tb[RTA_IIF])
> +		fld.flowidn_iif = nla_get_u32(tb[RTA_IIF]);
>  
>  	if (fld.flowidn_iif) {
>  		struct net_device *dev;
> @@ -1669,10 +1675,9 @@ static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void
>  		if (!err && -rt->dst.error)
>  			err = rt->dst.error;
>  	} else {
> -		int oif = 0;
> -		if (rta[RTA_OIF - 1])
> -			memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
> -		fld.flowidn_oif = oif;
> +		if (tb[RTA_OIF])
> +			fld.flowidn_oif = nla_get_u32(tb[RTA_OIF]);
> +
>  		err = dn_route_output_key((struct dst_entry **)&rt, &fld, 0);
>  	}
>  
> diff --git a/net/decnet/dn_table.c b/net/decnet/dn_table.c
> index 6c2445b..fc42a0a 100644
> --- a/net/decnet/dn_table.c
> +++ b/net/decnet/dn_table.c
> @@ -224,26 +224,27 @@ static struct dn_zone *dn_new_zone(struct dn_hash *table, int z)
>  }
>  
> 
> -static int dn_fib_nh_match(struct rtmsg *r, struct nlmsghdr *nlh, struct dn_kern_rta *rta, struct dn_fib_info *fi)
> +static int dn_fib_nh_match(struct rtmsg *r, struct nlmsghdr *nlh, struct nlattr *attrs[], struct dn_fib_info *fi)
>  {
>  	struct rtnexthop *nhp;
>  	int nhlen;
>  
> -	if (rta->rta_priority && *rta->rta_priority != fi->fib_priority)
> +	if (attrs[RTA_PRIORITY] &&
> +	    nla_get_u32(attrs[RTA_PRIORITY]) != fi->fib_priority)
>  		return 1;
>  
> -	if (rta->rta_oif || rta->rta_gw) {
> -		if ((!rta->rta_oif || *rta->rta_oif == fi->fib_nh->nh_oif) &&
> -		    (!rta->rta_gw  || memcmp(rta->rta_gw, &fi->fib_nh->nh_gw, 2) == 0))
> +	if (attrs[RTA_OIF] || attrs[RTA_GATEWAY]) {
> +		if ((!attrs[RTA_OIF] || nla_get_u32(attrs[RTA_OIF]) == fi->fib_nh->nh_oif) &&
> +		    (!attrs[RTA_GATEWAY]  || nla_get_le16(attrs[RTA_GATEWAY]) != fi->fib_nh->nh_gw))
>  			return 0;
>  		return 1;
>  	}
>  
> -	if (rta->rta_mp == NULL)
> +	if (!attrs[RTA_MULTIPATH])
>  		return 0;
>  
> -	nhp = RTA_DATA(rta->rta_mp);
> -	nhlen = RTA_PAYLOAD(rta->rta_mp);
> +	nhp = nla_data(attrs[RTA_MULTIPATH]);
> +	nhlen = nla_len(attrs[RTA_MULTIPATH]);
>  
>  	for_nexthops(fi) {
>  		int attrlen = nhlen - sizeof(struct rtnexthop);
> @@ -254,7 +255,10 @@ static int dn_fib_nh_match(struct rtmsg *r, struct nlmsghdr *nlh, struct dn_kern
>  		if (nhp->rtnh_ifindex && nhp->rtnh_ifindex != nh->nh_oif)
>  			return 1;
>  		if (attrlen) {
> -			gw = dn_fib_get_attr16(RTNH_DATA(nhp), attrlen, RTA_GATEWAY);
> +			struct nlattr *gw_attr;
> +
> +			gw_attr = nla_find((struct nlattr *) (nhp + 1), attrlen, RTA_GATEWAY);
> +			gw = gw_attr ? nla_get_le16(gw_attr) : 0;
>  
>  			if (gw && gw != nh->nh_gw)
>  				return 1;
> @@ -517,7 +521,8 @@ out:
>  	return skb->len;
>  }
>  
> -static int dn_fib_table_insert(struct dn_fib_table *tb, struct rtmsg *r, struct dn_kern_rta *rta, struct nlmsghdr *n, struct netlink_skb_parms *req)
> +static int dn_fib_table_insert(struct dn_fib_table *tb, struct rtmsg *r, struct nlattr *attrs[],
> +			       struct nlmsghdr *n, struct netlink_skb_parms *req)
>  {
>  	struct dn_hash *table = (struct dn_hash *)tb->data;
>  	struct dn_fib_node *new_f, *f, **fp, **del_fp;
> @@ -536,15 +541,14 @@ static int dn_fib_table_insert(struct dn_fib_table *tb, struct rtmsg *r, struct
>  		return -ENOBUFS;
>  
>  	dz_key_0(key);
> -	if (rta->rta_dst) {
> -		__le16 dst;
> -		memcpy(&dst, rta->rta_dst, 2);
> +	if (attrs[RTA_DST]) {
> +		__le16 dst = nla_get_le16(attrs[RTA_DST]);
>  		if (dst & ~DZ_MASK(dz))
>  			return -EINVAL;
>  		key = dz_key(dst, dz);
>  	}
>  
> -	if ((fi = dn_fib_create_info(r, rta, n, &err)) == NULL)
> +	if ((fi = dn_fib_create_info(r, attrs, n, &err)) == NULL)
>  		return err;
>  
>  	if (dz->dz_nent > (dz->dz_divisor << 2) &&
> @@ -654,7 +658,8 @@ out:
>  }
>  
> 
> -static int dn_fib_table_delete(struct dn_fib_table *tb, struct rtmsg *r, struct dn_kern_rta *rta, struct nlmsghdr *n, struct netlink_skb_parms *req)
> +static int dn_fib_table_delete(struct dn_fib_table *tb, struct rtmsg *r, struct nlattr *attrs[],
> +			       struct nlmsghdr *n, struct netlink_skb_parms *req)
>  {
>  	struct dn_hash *table = (struct dn_hash*)tb->data;
>  	struct dn_fib_node **fp, **del_fp, *f;
> @@ -671,9 +676,8 @@ static int dn_fib_table_delete(struct dn_fib_table *tb, struct rtmsg *r, struct
>  		return -ESRCH;
>  
>  	dz_key_0(key);
> -	if (rta->rta_dst) {
> -		__le16 dst;
> -		memcpy(&dst, rta->rta_dst, 2);
> +	if (attrs[RTA_DST]) {
> +		__le16 dst = nla_get_le16(attrs[RTA_DST]);
>  		if (dst & ~DZ_MASK(dz))
>  			return -EINVAL;
>  		key = dz_key(dst, dz);
> @@ -703,7 +707,7 @@ static int dn_fib_table_delete(struct dn_fib_table *tb, struct rtmsg *r, struct
>  				(r->rtm_scope == RT_SCOPE_NOWHERE || f->fn_scope == r->rtm_scope) &&
>  				(!r->rtm_protocol ||
>  					fi->fib_protocol == r->rtm_protocol) &&
> -				dn_fib_nh_match(r, n, rta, fi) == 0)
> +				dn_fib_nh_match(r, n, attrs, fi) == 0)
>  			del_fp = fp;
>  	}
>  


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Thomas Graf - March 22, 2013, 2:27 p.m.
On 03/21/13 at 06:04pm, Steven Whitehouse wrote:
> You shouldn't need any special hardware to test this. A copy of iproute2
> should be enough as you should be able to use that to create an
> interface or two and a route between them, etc. Although DECnet routing
> works in a different way to ip routing, the Linux implementation tries
> to stick fairly closely to the ip way of doing things whenever it can in
> order to share infrastructure. Now that ip has diverged a fair bit over
> time that isn't quite as true as it was, but there shouldn't be anything
> too surprising in there.

Alright, I did some basic testing with iproute2. I do not claim
to understand what I did but I ran the following:

$ ip -f dnet route add 1.661 dev em1
$ ip -f dnet route list
1.661 dev em1  scope link

$ ip -f dnet neigh add 6.662 dev em1
$ ip -f dnet neigh list
6.662 dev em1 lladdr aa:00:04:00:96:1a PERMANENT

$ ip -f dnet addr add 1.111 dev em1
$ ip -f dnet addr list
2: em1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN qlen 1000
    dnet 1.111/16 scope global em1
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Steven Whitehouse - March 22, 2013, 2:29 p.m.
Hi,

On Fri, 2013-03-22 at 14:27 +0000, Thomas Graf wrote:
> On 03/21/13 at 06:04pm, Steven Whitehouse wrote:
> > You shouldn't need any special hardware to test this. A copy of iproute2
> > should be enough as you should be able to use that to create an
> > interface or two and a route between them, etc. Although DECnet routing
> > works in a different way to ip routing, the Linux implementation tries
> > to stick fairly closely to the ip way of doing things whenever it can in
> > order to share infrastructure. Now that ip has diverged a fair bit over
> > time that isn't quite as true as it was, but there shouldn't be anything
> > too surprising in there.
> 
> Alright, I did some basic testing with iproute2. I do not claim
> to understand what I did but I ran the following:
> 
> $ ip -f dnet route add 1.661 dev em1
> $ ip -f dnet route list
> 1.661 dev em1  scope link
> 
> $ ip -f dnet neigh add 6.662 dev em1
> $ ip -f dnet neigh list
> 6.662 dev em1 lladdr aa:00:04:00:96:1a PERMANENT
> 
> $ ip -f dnet addr add 1.111 dev em1
> $ ip -f dnet addr list
> 2: em1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN qlen 1000
>     dnet 1.111/16 scope global em1

That looks sane to me. The only thing I could think of to add to that
list would be to use ip route get to do a lookup, but otherwise, that
seems to cover everything pretty much,

Steve.


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David Miller - March 22, 2013, 2:31 p.m.
From: Thomas Graf <tgraf@suug.ch>
Date: Fri, 22 Mar 2013 14:27:35 +0000

> On 03/21/13 at 06:04pm, Steven Whitehouse wrote:
>> You shouldn't need any special hardware to test this. A copy of iproute2
>> should be enough as you should be able to use that to create an
>> interface or two and a route between them, etc. Although DECnet routing
>> works in a different way to ip routing, the Linux implementation tries
>> to stick fairly closely to the ip way of doing things whenever it can in
>> order to share infrastructure. Now that ip has diverged a fair bit over
>> time that isn't quite as true as it was, but there shouldn't be anything
>> too surprising in there.
> 
> Alright, I did some basic testing with iproute2. I do not claim
> to understand what I did but I ran the following:
> 
> $ ip -f dnet route add 1.661 dev em1
> $ ip -f dnet route list
> 1.661 dev em1  scope link
> 
> $ ip -f dnet neigh add 6.662 dev em1
> $ ip -f dnet neigh list
> 6.662 dev em1 lladdr aa:00:04:00:96:1a PERMANENT
> 
> $ ip -f dnet addr add 1.111 dev em1
> $ ip -f dnet addr list
> 2: em1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN qlen 1000
>     dnet 1.111/16 scope global em1

That's good enough for me, both patches applied, thanks Thomas!
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Patch

diff --git a/include/net/dn_fib.h b/include/net/dn_fib.h
index 1ee9d4b..74004af 100644
--- a/include/net/dn_fib.h
+++ b/include/net/dn_fib.h
@@ -1,24 +1,9 @@ 
 #ifndef _NET_DN_FIB_H
 #define _NET_DN_FIB_H
 
-/* WARNING: The ordering of these elements must match ordering
- *          of RTA_* rtnetlink attribute numbers.
- */
-struct dn_kern_rta {
-        void            *rta_dst;
-        void            *rta_src;
-        int             *rta_iif;
-        int             *rta_oif;
-        void            *rta_gw;
-        u32             *rta_priority;
-        void            *rta_prefsrc;
-        struct rtattr   *rta_mx;
-        struct rtattr   *rta_mp;
-        unsigned char   *rta_protoinfo;
-        u32             *rta_flow;
-        struct rta_cacheinfo *rta_ci;
-	struct rta_session *rta_sess;
-};
+#include <linux/netlink.h>
+
+extern const struct nla_policy rtm_dn_policy[];
 
 struct dn_fib_res {
 	struct fib_rule *r;
@@ -93,10 +78,10 @@  struct dn_fib_table {
 	u32 n;
 
 	int (*insert)(struct dn_fib_table *t, struct rtmsg *r, 
-			struct dn_kern_rta *rta, struct nlmsghdr *n, 
+			struct nlattr *attrs[], struct nlmsghdr *n,
 			struct netlink_skb_parms *req);
 	int (*delete)(struct dn_fib_table *t, struct rtmsg *r,
-			struct dn_kern_rta *rta, struct nlmsghdr *n,
+			struct nlattr *attrs[], struct nlmsghdr *n,
 			struct netlink_skb_parms *req);
 	int (*lookup)(struct dn_fib_table *t, const struct flowidn *fld,
 			struct dn_fib_res *res);
@@ -116,13 +101,12 @@  extern void dn_fib_cleanup(void);
 extern int dn_fib_ioctl(struct socket *sock, unsigned int cmd, 
 			unsigned long arg);
 extern struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, 
-				struct dn_kern_rta *rta, 
+				struct nlattr *attrs[],
 				const struct nlmsghdr *nlh, int *errp);
 extern int dn_fib_semantic_match(int type, struct dn_fib_info *fi, 
 			const struct flowidn *fld,
 			struct dn_fib_res *res);
 extern void dn_fib_release_info(struct dn_fib_info *fi);
-extern __le16 dn_fib_get_attr16(struct rtattr *attr, int attrlen, int type);
 extern void dn_fib_flush(void);
 extern void dn_fib_select_multipath(const struct flowidn *fld,
 					struct dn_fib_res *res);
diff --git a/net/decnet/dn_fib.c b/net/decnet/dn_fib.c
index e36614e..42a8048 100644
--- a/net/decnet/dn_fib.c
+++ b/net/decnet/dn_fib.c
@@ -145,22 +145,10 @@  static inline struct dn_fib_info *dn_fib_find_info(const struct dn_fib_info *nfi
 	return NULL;
 }
 
-__le16 dn_fib_get_attr16(struct rtattr *attr, int attrlen, int type)
+static int dn_fib_count_nhs(const struct nlattr *attr)
 {
-	while(RTA_OK(attr,attrlen)) {
-		if (attr->rta_type == type)
-			return *(__le16*)RTA_DATA(attr);
-		attr = RTA_NEXT(attr, attrlen);
-	}
-
-	return 0;
-}
-
-static int dn_fib_count_nhs(struct rtattr *rta)
-{
-	int nhs = 0;
-	struct rtnexthop *nhp = RTA_DATA(rta);
-	int nhlen = RTA_PAYLOAD(rta);
+	struct rtnexthop *nhp = nla_data(attr);
+	int nhs = 0, nhlen = nla_len(attr);
 
 	while(nhlen >= (int)sizeof(struct rtnexthop)) {
 		if ((nhlen -= nhp->rtnh_len) < 0)
@@ -172,10 +160,11 @@  static int dn_fib_count_nhs(struct rtattr *rta)
 	return nhs;
 }
 
-static int dn_fib_get_nhs(struct dn_fib_info *fi, const struct rtattr *rta, const struct rtmsg *r)
+static int dn_fib_get_nhs(struct dn_fib_info *fi, const struct nlattr *attr,
+			  const struct rtmsg *r)
 {
-	struct rtnexthop *nhp = RTA_DATA(rta);
-	int nhlen = RTA_PAYLOAD(rta);
+	struct rtnexthop *nhp = nla_data(attr);
+	int nhlen = nla_len(attr);
 
 	change_nexthops(fi) {
 		int attrlen = nhlen - sizeof(struct rtnexthop);
@@ -187,7 +176,10 @@  static int dn_fib_get_nhs(struct dn_fib_info *fi, const struct rtattr *rta, cons
 		nh->nh_weight = nhp->rtnh_hops + 1;
 
 		if (attrlen) {
-			nh->nh_gw = dn_fib_get_attr16(RTNH_DATA(nhp), attrlen, RTA_GATEWAY);
+			struct nlattr *gw_attr;
+
+			gw_attr = nla_find((struct nlattr *) (nhp + 1), attrlen, RTA_GATEWAY);
+			nh->nh_gw = gw_attr ? nla_get_le16(gw_attr) : 0;
 		}
 		nhp = RTNH_NEXT(nhp);
 	} endfor_nexthops(fi);
@@ -268,7 +260,8 @@  out:
 }
 
 
-struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct dn_kern_rta *rta, const struct nlmsghdr *nlh, int *errp)
+struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct nlattr *attrs[],
+				       const struct nlmsghdr *nlh, int *errp)
 {
 	int err;
 	struct dn_fib_info *fi = NULL;
@@ -281,11 +274,9 @@  struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct dn_kern_rta
 	if (dn_fib_props[r->rtm_type].scope > r->rtm_scope)
 		goto err_inval;
 
-	if (rta->rta_mp) {
-		nhs = dn_fib_count_nhs(rta->rta_mp);
-		if (nhs == 0)
-			goto err_inval;
-	}
+	if (attrs[RTA_MULTIPATH] &&
+	    (nhs = dn_fib_count_nhs(attrs[RTA_MULTIPATH])) == 0)
+		goto err_inval;
 
 	fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct dn_fib_nh), GFP_KERNEL);
 	err = -ENOBUFS;
@@ -295,53 +286,65 @@  struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct dn_kern_rta
 	fi->fib_protocol = r->rtm_protocol;
 	fi->fib_nhs = nhs;
 	fi->fib_flags = r->rtm_flags;
-	if (rta->rta_priority)
-		fi->fib_priority = *rta->rta_priority;
-	if (rta->rta_mx) {
-		int attrlen = RTA_PAYLOAD(rta->rta_mx);
-		struct rtattr *attr = RTA_DATA(rta->rta_mx);
 
-		while(RTA_OK(attr, attrlen)) {
-			unsigned int flavour = attr->rta_type;
+	if (attrs[RTA_PRIORITY])
+		fi->fib_priority = nla_get_u32(attrs[RTA_PRIORITY]);
+
+	if (attrs[RTA_METRICS]) {
+		struct nlattr *attr;
+		int rem;
 
-			if (flavour) {
-				if (flavour > RTAX_MAX)
+		nla_for_each_nested(attr, attrs[RTA_METRICS], rem) {
+			int type = nla_type(attr);
+
+			if (type) {
+				if (type > RTAX_MAX || nla_len(attr) < 4)
 					goto err_inval;
-				fi->fib_metrics[flavour-1] = *(unsigned int *)RTA_DATA(attr);
+
+				fi->fib_metrics[type-1] = nla_get_u32(attr);
 			}
-			attr = RTA_NEXT(attr, attrlen);
 		}
 	}
-	if (rta->rta_prefsrc)
-		memcpy(&fi->fib_prefsrc, rta->rta_prefsrc, 2);
 
-	if (rta->rta_mp) {
-		if ((err = dn_fib_get_nhs(fi, rta->rta_mp, r)) != 0)
+	if (attrs[RTA_PREFSRC])
+		fi->fib_prefsrc = nla_get_le16(attrs[RTA_PREFSRC]);
+
+	if (attrs[RTA_MULTIPATH]) {
+		if ((err = dn_fib_get_nhs(fi, attrs[RTA_MULTIPATH], r)) != 0)
 			goto failure;
-		if (rta->rta_oif && fi->fib_nh->nh_oif != *rta->rta_oif)
+
+		if (attrs[RTA_OIF] &&
+		    fi->fib_nh->nh_oif != nla_get_u32(attrs[RTA_OIF]))
 			goto err_inval;
-		if (rta->rta_gw && memcmp(&fi->fib_nh->nh_gw, rta->rta_gw, 2))
+
+		if (attrs[RTA_GATEWAY] &&
+		    fi->fib_nh->nh_gw != nla_get_le16(attrs[RTA_GATEWAY]))
 			goto err_inval;
 	} else {
 		struct dn_fib_nh *nh = fi->fib_nh;
-		if (rta->rta_oif)
-			nh->nh_oif = *rta->rta_oif;
-		if (rta->rta_gw)
-			memcpy(&nh->nh_gw, rta->rta_gw, 2);
+
+		if (attrs[RTA_OIF])
+			nh->nh_oif = nla_get_u32(attrs[RTA_OIF]);
+
+		if (attrs[RTA_GATEWAY])
+			nh->nh_gw = nla_get_le16(attrs[RTA_GATEWAY]);
+
 		nh->nh_flags = r->rtm_flags;
 		nh->nh_weight = 1;
 	}
 
 	if (r->rtm_type == RTN_NAT) {
-		if (rta->rta_gw == NULL || nhs != 1 || rta->rta_oif)
+		if (!attrs[RTA_GATEWAY] || nhs != 1 || attrs[RTA_OIF])
 			goto err_inval;
-		memcpy(&fi->fib_nh->nh_gw, rta->rta_gw, 2);
+
+		fi->fib_nh->nh_gw = nla_get_le16(attrs[RTA_GATEWAY]);
 		goto link_it;
 	}
 
 	if (dn_fib_props[r->rtm_type].error) {
-		if (rta->rta_gw || rta->rta_oif || rta->rta_mp)
+		if (attrs[RTA_GATEWAY] || attrs[RTA_OIF] || attrs[RTA_MULTIPATH])
 			goto err_inval;
+
 		goto link_it;
 	}
 
@@ -367,8 +370,8 @@  struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct dn_kern_rta
 	}
 
 	if (fi->fib_prefsrc) {
-		if (r->rtm_type != RTN_LOCAL || rta->rta_dst == NULL ||
-		    memcmp(&fi->fib_prefsrc, rta->rta_dst, 2))
+		if (r->rtm_type != RTN_LOCAL || !attrs[RTA_DST] ||
+		    fi->fib_prefsrc != nla_get_le16(attrs[RTA_DST]))
 			if (dnet_addr_type(fi->fib_prefsrc) != RTN_LOCAL)
 				goto err_inval;
 	}
@@ -486,29 +489,24 @@  void dn_fib_select_multipath(const struct flowidn *fld, struct dn_fib_res *res)
 	spin_unlock_bh(&dn_fib_multipath_lock);
 }
 
+const struct nla_policy rtm_dn_policy[RTA_MAX + 1] = {
+	[RTA_DST]		= { .type = NLA_U16 },
+	[RTA_SRC]		= { .type = NLA_U16 },
+	[RTA_IIF]		= { .type = NLA_U32 },
+	[RTA_OIF]		= { .type = NLA_U32 },
+	[RTA_GATEWAY]		= { .type = NLA_U16 },
+	[RTA_PRIORITY]		= { .type = NLA_U32 },
+	[RTA_PREFSRC]		= { .type = NLA_U16 },
+	[RTA_METRICS]		= { .type = NLA_NESTED },
+	[RTA_MULTIPATH]		= { .type = NLA_NESTED },
+	[RTA_TABLE]		= { .type = NLA_U32 },
+	[RTA_MARK]		= { .type = NLA_U32 },
+};
 
-static int dn_fib_check_attr(struct rtmsg *r, struct rtattr **rta)
-{
-	int i;
-
-	for(i = 1; i <= RTA_MAX; i++) {
-		struct rtattr *attr = rta[i-1];
-		if (attr) {
-			if (RTA_PAYLOAD(attr) < 4 && RTA_PAYLOAD(attr) != 2)
-				return -EINVAL;
-			if (i != RTA_MULTIPATH && i != RTA_METRICS &&
-			    i != RTA_TABLE)
-				rta[i-1] = (struct rtattr *)RTA_DATA(attr);
-		}
-	}
-
-	return 0;
-}
-
-static inline u32 rtm_get_table(struct rtattr **rta, u8 table)
+static inline u32 rtm_get_table(struct nlattr *attrs[], u8 table)
 {
-	if (rta[RTA_TABLE - 1])
-		table = nla_get_u32((struct nlattr *) rta[RTA_TABLE - 1]);
+	if (attrs[RTA_TABLE])
+		table = nla_get_u32(attrs[RTA_TABLE]);
 
 	return table;
 }
@@ -517,8 +515,9 @@  static int dn_fib_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *
 {
 	struct net *net = sock_net(skb->sk);
 	struct dn_fib_table *tb;
-	struct rtattr **rta = arg;
-	struct rtmsg *r = NLMSG_DATA(nlh);
+	struct rtmsg *r = nlmsg_data(nlh);
+	struct nlattr *attrs[RTA_MAX+1];
+	int err;
 
 	if (!capable(CAP_NET_ADMIN))
 		return -EPERM;
@@ -526,22 +525,24 @@  static int dn_fib_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *
 	if (!net_eq(net, &init_net))
 		return -EINVAL;
 
-	if (dn_fib_check_attr(r, rta))
-		return -EINVAL;
+	err = nlmsg_parse(nlh, sizeof(*r), attrs, RTA_MAX, rtm_dn_policy);
+	if (err < 0)
+		return err;
 
-	tb = dn_fib_get_table(rtm_get_table(rta, r->rtm_table), 0);
-	if (tb)
-		return tb->delete(tb, r, (struct dn_kern_rta *)rta, nlh, &NETLINK_CB(skb));
+	tb = dn_fib_get_table(rtm_get_table(attrs, r->rtm_table), 0);
+	if (!tb)
+		return -ESRCH;
 
-	return -ESRCH;
+	return tb->delete(tb, r, attrs, nlh, &NETLINK_CB(skb));
 }
 
 static int dn_fib_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 {
 	struct net *net = sock_net(skb->sk);
 	struct dn_fib_table *tb;
-	struct rtattr **rta = arg;
-	struct rtmsg *r = NLMSG_DATA(nlh);
+	struct rtmsg *r = nlmsg_data(nlh);
+	struct nlattr *attrs[RTA_MAX+1];
+	int err;
 
 	if (!capable(CAP_NET_ADMIN))
 		return -EPERM;
@@ -549,14 +550,15 @@  static int dn_fib_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *
 	if (!net_eq(net, &init_net))
 		return -EINVAL;
 
-	if (dn_fib_check_attr(r, rta))
-		return -EINVAL;
+	err = nlmsg_parse(nlh, sizeof(*r), attrs, RTA_MAX, rtm_dn_policy);
+	if (err < 0)
+		return err;
 
-	tb = dn_fib_get_table(rtm_get_table(rta, r->rtm_table), 1);
-	if (tb)
-		return tb->insert(tb, r, (struct dn_kern_rta *)rta, nlh, &NETLINK_CB(skb));
+	tb = dn_fib_get_table(rtm_get_table(attrs, r->rtm_table), 1);
+	if (!tb)
+		return -ENOBUFS;
 
-	return -ENOBUFS;
+	return tb->insert(tb, r, attrs, nlh, &NETLINK_CB(skb));
 }
 
 static void fib_magic(int cmd, int type, __le16 dst, int dst_len, struct dn_ifaddr *ifa)
@@ -566,10 +568,31 @@  static void fib_magic(int cmd, int type, __le16 dst, int dst_len, struct dn_ifad
 		struct nlmsghdr nlh;
 		struct rtmsg rtm;
 	} req;
-	struct dn_kern_rta rta;
+	struct {
+		struct nlattr hdr;
+		__le16 dst;
+	} dst_attr = {
+		.dst = dst,
+	};
+	struct {
+		struct nlattr hdr;
+		__le16 prefsrc;
+	} prefsrc_attr = {
+		.prefsrc = ifa->ifa_local,
+	};
+	struct {
+		struct nlattr hdr;
+		u32 oif;
+	} oif_attr = {
+		.oif = ifa->ifa_dev->dev->ifindex,
+	};
+	struct nlattr *attrs[RTA_MAX+1] = {
+		[RTA_DST] = (struct nlattr *) &dst_attr,
+		[RTA_PREFSRC] = (struct nlattr * ) &prefsrc_attr,
+		[RTA_OIF] = (struct nlattr *) &oif_attr,
+	};
 
 	memset(&req.rtm, 0, sizeof(req.rtm));
-	memset(&rta, 0, sizeof(rta));
 
 	if (type == RTN_UNICAST)
 		tb = dn_fib_get_table(RT_MIN_TABLE, 1);
@@ -591,14 +614,10 @@  static void fib_magic(int cmd, int type, __le16 dst, int dst_len, struct dn_ifad
 	req.rtm.rtm_scope = (type != RTN_LOCAL ? RT_SCOPE_LINK : RT_SCOPE_HOST);
 	req.rtm.rtm_type = type;
 
-	rta.rta_dst = &dst;
-	rta.rta_prefsrc = &ifa->ifa_local;
-	rta.rta_oif = &ifa->ifa_dev->dev->ifindex;
-
 	if (cmd == RTM_NEWROUTE)
-		tb->insert(tb, &req.rtm, &rta, &req.nlh, NULL);
+		tb->insert(tb, &req.rtm, attrs, &req.nlh, NULL);
 	else
-		tb->delete(tb, &req.rtm, &rta, &req.nlh, NULL);
+		tb->delete(tb, &req.rtm, attrs, &req.nlh, NULL);
 }
 
 static void dn_fib_add_ifaddr(struct dn_ifaddr *ifa)
diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index 5ac0e15..b4b3508 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -1619,17 +1619,21 @@  errout:
 static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
 {
 	struct net *net = sock_net(in_skb->sk);
-	struct rtattr **rta = arg;
 	struct rtmsg *rtm = nlmsg_data(nlh);
 	struct dn_route *rt = NULL;
 	struct dn_skb_cb *cb;
 	int err;
 	struct sk_buff *skb;
 	struct flowidn fld;
+	struct nlattr *tb[RTA_MAX+1];
 
 	if (!net_eq(net, &init_net))
 		return -EINVAL;
 
+	err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_dn_policy);
+	if (err < 0)
+		return err;
+
 	memset(&fld, 0, sizeof(fld));
 	fld.flowidn_proto = DNPROTO_NSP;
 
@@ -1639,12 +1643,14 @@  static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void
 	skb_reset_mac_header(skb);
 	cb = DN_SKB_CB(skb);
 
-	if (rta[RTA_SRC-1])
-		memcpy(&fld.saddr, RTA_DATA(rta[RTA_SRC-1]), 2);
-	if (rta[RTA_DST-1])
-		memcpy(&fld.daddr, RTA_DATA(rta[RTA_DST-1]), 2);
-	if (rta[RTA_IIF-1])
-		memcpy(&fld.flowidn_iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
+	if (tb[RTA_SRC])
+		fld.saddr = nla_get_le16(tb[RTA_SRC]);
+
+	if (tb[RTA_DST])
+		fld.daddr = nla_get_le16(tb[RTA_DST]);
+
+	if (tb[RTA_IIF])
+		fld.flowidn_iif = nla_get_u32(tb[RTA_IIF]);
 
 	if (fld.flowidn_iif) {
 		struct net_device *dev;
@@ -1669,10 +1675,9 @@  static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void
 		if (!err && -rt->dst.error)
 			err = rt->dst.error;
 	} else {
-		int oif = 0;
-		if (rta[RTA_OIF - 1])
-			memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
-		fld.flowidn_oif = oif;
+		if (tb[RTA_OIF])
+			fld.flowidn_oif = nla_get_u32(tb[RTA_OIF]);
+
 		err = dn_route_output_key((struct dst_entry **)&rt, &fld, 0);
 	}
 
diff --git a/net/decnet/dn_table.c b/net/decnet/dn_table.c
index 6c2445b..fc42a0a 100644
--- a/net/decnet/dn_table.c
+++ b/net/decnet/dn_table.c
@@ -224,26 +224,27 @@  static struct dn_zone *dn_new_zone(struct dn_hash *table, int z)
 }
 
 
-static int dn_fib_nh_match(struct rtmsg *r, struct nlmsghdr *nlh, struct dn_kern_rta *rta, struct dn_fib_info *fi)
+static int dn_fib_nh_match(struct rtmsg *r, struct nlmsghdr *nlh, struct nlattr *attrs[], struct dn_fib_info *fi)
 {
 	struct rtnexthop *nhp;
 	int nhlen;
 
-	if (rta->rta_priority && *rta->rta_priority != fi->fib_priority)
+	if (attrs[RTA_PRIORITY] &&
+	    nla_get_u32(attrs[RTA_PRIORITY]) != fi->fib_priority)
 		return 1;
 
-	if (rta->rta_oif || rta->rta_gw) {
-		if ((!rta->rta_oif || *rta->rta_oif == fi->fib_nh->nh_oif) &&
-		    (!rta->rta_gw  || memcmp(rta->rta_gw, &fi->fib_nh->nh_gw, 2) == 0))
+	if (attrs[RTA_OIF] || attrs[RTA_GATEWAY]) {
+		if ((!attrs[RTA_OIF] || nla_get_u32(attrs[RTA_OIF]) == fi->fib_nh->nh_oif) &&
+		    (!attrs[RTA_GATEWAY]  || nla_get_le16(attrs[RTA_GATEWAY]) != fi->fib_nh->nh_gw))
 			return 0;
 		return 1;
 	}
 
-	if (rta->rta_mp == NULL)
+	if (!attrs[RTA_MULTIPATH])
 		return 0;
 
-	nhp = RTA_DATA(rta->rta_mp);
-	nhlen = RTA_PAYLOAD(rta->rta_mp);
+	nhp = nla_data(attrs[RTA_MULTIPATH]);
+	nhlen = nla_len(attrs[RTA_MULTIPATH]);
 
 	for_nexthops(fi) {
 		int attrlen = nhlen - sizeof(struct rtnexthop);
@@ -254,7 +255,10 @@  static int dn_fib_nh_match(struct rtmsg *r, struct nlmsghdr *nlh, struct dn_kern
 		if (nhp->rtnh_ifindex && nhp->rtnh_ifindex != nh->nh_oif)
 			return 1;
 		if (attrlen) {
-			gw = dn_fib_get_attr16(RTNH_DATA(nhp), attrlen, RTA_GATEWAY);
+			struct nlattr *gw_attr;
+
+			gw_attr = nla_find((struct nlattr *) (nhp + 1), attrlen, RTA_GATEWAY);
+			gw = gw_attr ? nla_get_le16(gw_attr) : 0;
 
 			if (gw && gw != nh->nh_gw)
 				return 1;
@@ -517,7 +521,8 @@  out:
 	return skb->len;
 }
 
-static int dn_fib_table_insert(struct dn_fib_table *tb, struct rtmsg *r, struct dn_kern_rta *rta, struct nlmsghdr *n, struct netlink_skb_parms *req)
+static int dn_fib_table_insert(struct dn_fib_table *tb, struct rtmsg *r, struct nlattr *attrs[],
+			       struct nlmsghdr *n, struct netlink_skb_parms *req)
 {
 	struct dn_hash *table = (struct dn_hash *)tb->data;
 	struct dn_fib_node *new_f, *f, **fp, **del_fp;
@@ -536,15 +541,14 @@  static int dn_fib_table_insert(struct dn_fib_table *tb, struct rtmsg *r, struct
 		return -ENOBUFS;
 
 	dz_key_0(key);
-	if (rta->rta_dst) {
-		__le16 dst;
-		memcpy(&dst, rta->rta_dst, 2);
+	if (attrs[RTA_DST]) {
+		__le16 dst = nla_get_le16(attrs[RTA_DST]);
 		if (dst & ~DZ_MASK(dz))
 			return -EINVAL;
 		key = dz_key(dst, dz);
 	}
 
-	if ((fi = dn_fib_create_info(r, rta, n, &err)) == NULL)
+	if ((fi = dn_fib_create_info(r, attrs, n, &err)) == NULL)
 		return err;
 
 	if (dz->dz_nent > (dz->dz_divisor << 2) &&
@@ -654,7 +658,8 @@  out:
 }
 
 
-static int dn_fib_table_delete(struct dn_fib_table *tb, struct rtmsg *r, struct dn_kern_rta *rta, struct nlmsghdr *n, struct netlink_skb_parms *req)
+static int dn_fib_table_delete(struct dn_fib_table *tb, struct rtmsg *r, struct nlattr *attrs[],
+			       struct nlmsghdr *n, struct netlink_skb_parms *req)
 {
 	struct dn_hash *table = (struct dn_hash*)tb->data;
 	struct dn_fib_node **fp, **del_fp, *f;
@@ -671,9 +676,8 @@  static int dn_fib_table_delete(struct dn_fib_table *tb, struct rtmsg *r, struct
 		return -ESRCH;
 
 	dz_key_0(key);
-	if (rta->rta_dst) {
-		__le16 dst;
-		memcpy(&dst, rta->rta_dst, 2);
+	if (attrs[RTA_DST]) {
+		__le16 dst = nla_get_le16(attrs[RTA_DST]);
 		if (dst & ~DZ_MASK(dz))
 			return -EINVAL;
 		key = dz_key(dst, dz);
@@ -703,7 +707,7 @@  static int dn_fib_table_delete(struct dn_fib_table *tb, struct rtmsg *r, struct
 				(r->rtm_scope == RT_SCOPE_NOWHERE || f->fn_scope == r->rtm_scope) &&
 				(!r->rtm_protocol ||
 					fi->fib_protocol == r->rtm_protocol) &&
-				dn_fib_nh_match(r, n, rta, fi) == 0)
+				dn_fib_nh_match(r, n, attrs, fi) == 0)
 			del_fp = fp;
 	}