[NETLINK]: Neighbour table configuration and statistics via rtnetlink

To retrieve the neighbour tables send RTM_GETNEIGHTBL with the
NLM_F_DUMP flag set. Every neighbour table configuration is
spread over multiple messages to avoid running into message
size limits on systems with many interfaces. The first message
in the sequence transports all not device specific data such as
statistics, configuration, and the default parameter set.
This message is followed by 0..n messages carrying device
specific parameter sets.

Although the ordering should be sufficient, NDTA_NAME can be
used to identify sequences. The initial message can be identified
by checking for NDTA_CONFIG. The device specific messages do
not contain this TLV but have NDTPA_IFINDEX set to the
corresponding interface index.

To change neighbour table attributes, send RTM_SETNEIGHTBL
with NDTA_NAME set. Changeable attribute include NDTA_THRESH[1-3],
NDTA_GC_INTERVAL, and all TLVs in NDTA_PARMS unless marked
otherwise. Device specific parameter sets can be changed by
setting NDTPA_IFINDEX to the interface index of the corresponding
device.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 314 insertions, 3 deletions

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 43bdc52..0841ac7 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1276,9 +1276,14 @@ struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
 		INIT_RCU_HEAD(&p->rcu_head);
 		p->reachable_time =
 				neigh_rand_reach_time(p->base_reachable_time);
-		if (dev && dev->neigh_setup && dev->neigh_setup(dev, p)) {
-			kfree(p);
-			return NULL;
+		if (dev) {
+			if (dev->neigh_setup && dev->neigh_setup(dev, p)) {
+				kfree(p);
+				return NULL;
+			}
+
+			dev_hold(dev);
+			p->dev = dev;
 		}
 		p->sysctl_table = NULL;
 		write_lock_bh(&tbl->lock);
@@ -1309,6 +1314,8 @@ void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms)
 			*p = parms->next;
 			parms->dead = 1;
 			write_unlock_bh(&tbl->lock);
+			if (parms->dev)
+				dev_put(parms->dev);
 			call_rcu(&parms->rcu_head, neigh_rcu_free_parms);
 			return;
 		}
@@ -1546,6 +1553,308 @@ out:
 	return err;
 }
 
+static int neightbl_fill_parms(struct sk_buff *skb, struct neigh_parms *parms)
+{
+	struct rtattr *nest = RTA_NEST(skb, NDTA_PARMS);
+
+	if (parms->dev)
+		RTA_PUT_U32(skb, NDTPA_IFINDEX, parms->dev->ifindex);
+
+	RTA_PUT_U32(skb, NDTPA_REFCNT, atomic_read(&parms->refcnt));
+	RTA_PUT_U32(skb, NDTPA_QUEUE_LEN, parms->queue_len);
+	RTA_PUT_U32(skb, NDTPA_PROXY_QLEN, parms->proxy_qlen);
+	RTA_PUT_U32(skb, NDTPA_APP_PROBES, parms->app_probes);
+	RTA_PUT_U32(skb, NDTPA_UCAST_PROBES, parms->ucast_probes);
+	RTA_PUT_U32(skb, NDTPA_MCAST_PROBES, parms->mcast_probes);
+	RTA_PUT_MSECS(skb, NDTPA_REACHABLE_TIME, parms->reachable_time);
+	RTA_PUT_MSECS(skb, NDTPA_BASE_REACHABLE_TIME,
+		      parms->base_reachable_time);
+	RTA_PUT_MSECS(skb, NDTPA_GC_STALETIME, parms->gc_staletime);
+	RTA_PUT_MSECS(skb, NDTPA_DELAY_PROBE_TIME, parms->delay_probe_time);
+	RTA_PUT_MSECS(skb, NDTPA_RETRANS_TIME, parms->retrans_time);
+	RTA_PUT_MSECS(skb, NDTPA_ANYCAST_DELAY, parms->anycast_delay);
+	RTA_PUT_MSECS(skb, NDTPA_PROXY_DELAY, parms->proxy_delay);
+	RTA_PUT_MSECS(skb, NDTPA_LOCKTIME, parms->locktime);
+
+	return RTA_NEST_END(skb, nest);
+
+rtattr_failure:
+	return RTA_NEST_CANCEL(skb, nest);
+}
+
+static int neightbl_fill_info(struct neigh_table *tbl, struct sk_buff *skb,
+			      struct netlink_callback *cb)
+{
+	struct nlmsghdr *nlh;
+	struct ndtmsg *ndtmsg;
+
+	nlh = NLMSG_PUT_ANSWER(skb, cb, RTM_NEWNEIGHTBL, sizeof(struct ndtmsg));
+	ndtmsg = NLMSG_DATA(nlh);
+
+	NLMSG_SET_MULTIPART(nlh);
+
+	read_lock_bh(&tbl->lock);
+	ndtmsg->ndtm_family = tbl->family;
+
+	RTA_PUT_STRING(skb, NDTA_NAME, tbl->id);
+	RTA_PUT_MSECS(skb, NDTA_GC_INTERVAL, tbl->gc_interval);
+	RTA_PUT_U32(skb, NDTA_THRESH1, tbl->gc_thresh1);
+	RTA_PUT_U32(skb, NDTA_THRESH2, tbl->gc_thresh2);
+	RTA_PUT_U32(skb, NDTA_THRESH3, tbl->gc_thresh3);
+
+	{
+		unsigned long now = jiffies;
+		unsigned int flush_delta = now - tbl->last_flush;
+		unsigned int rand_delta = now - tbl->last_rand;
+
+		struct ndt_config ndc = {
+			.ndtc_key_len		= tbl->key_len,
+			.ndtc_entry_size	= tbl->entry_size,
+			.ndtc_entries		= atomic_read(&tbl->entries),
+			.ndtc_last_flush	= jiffies_to_msecs(flush_delta),
+			.ndtc_last_rand		= jiffies_to_msecs(rand_delta),
+			.ndtc_hash_rnd		= tbl->hash_rnd,
+			.ndtc_hash_mask		= tbl->hash_mask,
+			.ndtc_hash_chain_gc	= tbl->hash_chain_gc,
+			.ndtc_proxy_qlen	= tbl->proxy_queue.qlen,
+		};
+
+		RTA_PUT(skb, NDTA_CONFIG, sizeof(ndc), &ndc);
+	}
+
+	{
+		int cpu;
+		struct ndt_stats ndst;
+
+		memset(&ndst, 0, sizeof(ndst));
+
+		for (cpu = 0; cpu < NR_CPUS; cpu++) {
+			struct neigh_statistics	*st;
+
+			if (!cpu_possible(cpu))
+				continue;
+
+			st = per_cpu_ptr(tbl->stats, cpu);
+			ndst.ndts_allocs		+= st->allocs;
+			ndst.ndts_destroys		+= st->destroys;
+			ndst.ndts_hash_grows		+= st->hash_grows;
+			ndst.ndts_res_failed		+= st->res_failed;
+			ndst.ndts_lookups		+= st->lookups;
+			ndst.ndts_hits			+= st->hits;
+			ndst.ndts_rcv_probes_mcast	+= st->rcv_probes_mcast;
+			ndst.ndts_rcv_probes_ucast	+= st->rcv_probes_ucast;
+			ndst.ndts_periodic_gc_runs	+= st->periodic_gc_runs;
+			ndst.ndts_forced_gc_runs	+= st->forced_gc_runs;
+		}
+
+		RTA_PUT(skb, NDTA_STATS, sizeof(ndst), &ndst);
+	}
+
+	BUG_ON(tbl->parms.dev);
+	if (neightbl_fill_parms(skb, &tbl->parms) < 0)
+		goto rtattr_failure;
+
+	read_unlock_bh(&tbl->lock);
+	return NLMSG_END(skb, nlh);
+
+rtattr_failure:
+	read_unlock_bh(&tbl->lock);
+	return NLMSG_CANCEL(skb, nlh);
+ 
+nlmsg_failure:
+	return -1;
+}
+
+static int neightbl_fill_param_info(struct neigh_table *tbl,
+				    struct neigh_parms *parms,
+				    struct sk_buff *skb,
+				    struct netlink_callback *cb)
+{
+	struct ndtmsg *ndtmsg;
+	struct nlmsghdr *nlh;
+
+	nlh = NLMSG_PUT_ANSWER(skb, cb, RTM_NEWNEIGHTBL, sizeof(struct ndtmsg));
+	ndtmsg = NLMSG_DATA(nlh);
+
+	NLMSG_SET_MULTIPART(nlh);
+
+	read_lock_bh(&tbl->lock);
+	ndtmsg->ndtm_family = tbl->family;
+	RTA_PUT_STRING(skb, NDTA_NAME, tbl->id);
+
+	if (neightbl_fill_parms(skb, parms) < 0)
+		goto rtattr_failure;
+
+	read_unlock_bh(&tbl->lock);
+	return NLMSG_END(skb, nlh);
+
+rtattr_failure:
+	read_unlock_bh(&tbl->lock);
+	return NLMSG_CANCEL(skb, nlh);
+
+nlmsg_failure:
+	return -1;
+}
+ 
+static inline struct neigh_parms *lookup_neigh_params(struct neigh_table *tbl,
+						      int ifindex)
+{
+	struct neigh_parms *p;
+	
+	for (p = &tbl->parms; p; p = p->next)
+		if ((p->dev && p->dev->ifindex == ifindex) ||
+		    (!p->dev && !ifindex))
+			return p;
+
+	return NULL;
+}
+
+int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
+{
+	struct neigh_table *tbl;
+	struct ndtmsg *ndtmsg = NLMSG_DATA(nlh);
+	struct rtattr **tb = arg;
+	int err = -EINVAL;
+
+	if (!tb[NDTA_NAME - 1] || !RTA_PAYLOAD(tb[NDTA_NAME - 1]))
+		return -EINVAL;
+
+	read_lock(&neigh_tbl_lock);
+	for (tbl = neigh_tables; tbl; tbl = tbl->next) {
+		if (ndtmsg->ndtm_family && tbl->family != ndtmsg->ndtm_family)
+			continue;
+
+		if (!rtattr_strcmp(tb[NDTA_NAME - 1], tbl->id))
+			break;
+	}
+
+	if (tbl == NULL) {
+		err = -ENOENT;
+		goto errout;
+	}
+
+	/* 
+	 * We acquire tbl->lock to be nice to the periodic timers and
+	 * make sure they always see a consistent set of values.
+	 */
+	write_lock_bh(&tbl->lock);
+
+	if (tb[NDTA_THRESH1 - 1])
+		tbl->gc_thresh1 = RTA_GET_U32(tb[NDTA_THRESH1 - 1]);
+
+	if (tb[NDTA_THRESH2 - 1])
+		tbl->gc_thresh2 = RTA_GET_U32(tb[NDTA_THRESH2 - 1]);
+
+	if (tb[NDTA_THRESH3 - 1])
+		tbl->gc_thresh3 = RTA_GET_U32(tb[NDTA_THRESH3 - 1]);
+
+	if (tb[NDTA_GC_INTERVAL - 1])
+		tbl->gc_interval = RTA_GET_MSECS(tb[NDTA_GC_INTERVAL - 1]);
+
+	if (tb[NDTA_PARMS - 1]) {
+		struct rtattr *tbp[NDTPA_MAX];
+		struct neigh_parms *p;
+		u32 ifindex = 0;
+
+		if (rtattr_parse_nested(tbp, NDTPA_MAX, tb[NDTA_PARMS - 1]) < 0)
+			goto rtattr_failure;
+
+		if (tbp[NDTPA_IFINDEX - 1])
+			ifindex = RTA_GET_U32(tbp[NDTPA_IFINDEX - 1]);
+
+		p = lookup_neigh_params(tbl, ifindex);
+		if (p == NULL) {
+			err = -ENOENT;
+			goto rtattr_failure;
+		}
+	
+		if (tbp[NDTPA_QUEUE_LEN - 1])
+			p->queue_len = RTA_GET_U32(tbp[NDTPA_QUEUE_LEN - 1]);
+
+		if (tbp[NDTPA_PROXY_QLEN - 1])
+			p->proxy_qlen = RTA_GET_U32(tbp[NDTPA_PROXY_QLEN - 1]);
+
+		if (tbp[NDTPA_APP_PROBES - 1])
+			p->app_probes = RTA_GET_U32(tbp[NDTPA_APP_PROBES - 1]);
+
+		if (tbp[NDTPA_UCAST_PROBES - 1])
+			p->ucast_probes =
+			   RTA_GET_U32(tbp[NDTPA_UCAST_PROBES - 1]);
+
+		if (tbp[NDTPA_MCAST_PROBES - 1])
+			p->mcast_probes =
+			   RTA_GET_U32(tbp[NDTPA_MCAST_PROBES - 1]);
+
+		if (tbp[NDTPA_BASE_REACHABLE_TIME - 1])
+			p->base_reachable_time =
+			   RTA_GET_MSECS(tbp[NDTPA_BASE_REACHABLE_TIME - 1]);
+
+		if (tbp[NDTPA_GC_STALETIME - 1])
+			p->gc_staletime =
+			   RTA_GET_MSECS(tbp[NDTPA_GC_STALETIME - 1]);
+
+		if (tbp[NDTPA_DELAY_PROBE_TIME - 1])
+			p->delay_probe_time =
+			   RTA_GET_MSECS(tbp[NDTPA_DELAY_PROBE_TIME - 1]);
+
+		if (tbp[NDTPA_RETRANS_TIME - 1])
+			p->retrans_time =
+			   RTA_GET_MSECS(tbp[NDTPA_RETRANS_TIME - 1]);
+
+		if (tbp[NDTPA_ANYCAST_DELAY - 1])
+			p->anycast_delay =
+			   RTA_GET_MSECS(tbp[NDTPA_ANYCAST_DELAY - 1]);
+
+		if (tbp[NDTPA_PROXY_DELAY - 1])
+			p->proxy_delay =
+			   RTA_GET_MSECS(tbp[NDTPA_PROXY_DELAY - 1]);
+
+		if (tbp[NDTPA_LOCKTIME - 1])
+			p->locktime = RTA_GET_MSECS(tbp[NDTPA_LOCKTIME - 1]);
+	}
+
+	err = 0;
+
+rtattr_failure:
+	write_unlock_bh(&tbl->lock);
+errout:
+	read_unlock(&neigh_tbl_lock);
+	return err;
+}
+
+int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	int idx, family;
+	int s_idx = cb->args[0];
+	struct neigh_table *tbl;
+
+	family = ((struct rtgenmsg *)NLMSG_DATA(cb->nlh))->rtgen_family;
+
+	read_lock(&neigh_tbl_lock);
+	for (tbl = neigh_tables, idx = 0; tbl; tbl = tbl->next) {
+		struct neigh_parms *p;
+
+		if (idx < s_idx || (family && tbl->family != family))
+			continue;
+
+		if (neightbl_fill_info(tbl, skb, cb) <= 0)
+			break;
+
+		for (++idx, p = tbl->parms.next; p; p = p->next, idx++) {
+			if (idx < s_idx)
+				continue;
+
+			if (neightbl_fill_param_info(tbl, p, skb, cb) <= 0)
+				goto out;
+		}
+
+	}
+out:
+	read_unlock(&neigh_tbl_lock);
+	cb->args[0] = idx;
+
+	return skb->len;
+}
 
 static int neigh_fill_info(struct sk_buff *skb, struct neighbour *n,
 			   u32 pid, u32 seq, int event)
@@ -2352,6 +2661,8 @@ EXPORT_SYMBOL(neigh_update);
 EXPORT_SYMBOL(neigh_update_hhs);
 EXPORT_SYMBOL(pneigh_enqueue);
 EXPORT_SYMBOL(pneigh_lookup);
+EXPORT_SYMBOL(neightbl_dump_info);
+EXPORT_SYMBOL(neightbl_set);
 
 #ifdef CONFIG_ARPD
 EXPORT_SYMBOL(neigh_app_ns);