[PATCH net 3/4] net: Don't return invalid table id error when dumping all families

[David Ahern <dsahern@kernel.org>]

From: David Ahern <dsahern@gmail.com>

When doing a route dump across all address families, do not error out
if the table does not exist. This allows a route dump for AF_UNSPEC
with a table id that may only exist for some of the families.

Do return the table does not exist error if dumping routes for a
specific family and the table does not exist.

Signed-off-by: David Ahern <dsahern@gmail.com>
---
 include/net/ip_fib.h    | 1 +
 net/ipv4/fib_frontend.c | 4 ++++
 net/ipv4/ipmr.c         | 3 +++
 net/ipv6/ip6_fib.c      | 3 +++
 net/ipv6/ip6mr.c        | 3 +++
 5 files changed, 14 insertions(+)

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index e8d9456bf36e..c5969762a8f4 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -226,6 +226,7 @@ struct fib_dump_filter {
 	u32			table_id;
 	/* filter_set is an optimization that an entry is set */
 	bool			filter_set;
+	bool			dump_all_families;
 	unsigned char		protocol;
 	unsigned char		rt_type;
 	unsigned int		flags;
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 5bf653f36911..6df95be96311 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -829,6 +829,7 @@ int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
 		return -EINVAL;
 	}
 
+	filter->dump_all_families = (rtm->rtm_family == AF_UNSPEC);
 	filter->flags    = rtm->rtm_flags;
 	filter->protocol = rtm->rtm_protocol;
 	filter->rt_type  = rtm->rtm_type;
@@ -899,6 +900,9 @@ static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 	if (filter.table_id) {
 		tb = fib_get_table(net, filter.table_id);
 		if (!tb) {
+			if (filter.dump_all_families)
+				return skb->len;
+
 			NL_SET_ERR_MSG(cb->extack, "ipv4: FIB table does not exist");
 			return -ENOENT;
 		}
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 7a3e2acda94c..a6defbec4f1b 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -2542,6 +2542,9 @@ static int ipmr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb)
 
 		mrt = ipmr_get_table(sock_net(skb->sk), filter.table_id);
 		if (!mrt) {
+			if (filter.dump_all_families)
+				return skb->len;
+
 			NL_SET_ERR_MSG(cb->extack, "ipv4: MR table does not exist");
 			return -ENOENT;
 		}
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 2a058b408a6a..1b8bc008b53b 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -620,6 +620,9 @@ static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 	if (arg.filter.table_id) {
 		tb = fib6_get_table(net, arg.filter.table_id);
 		if (!tb) {
+			if (arg.filter.dump_all_families)
+				return skb->len;
+
 			NL_SET_ERR_MSG_MOD(cb->extack, "FIB table does not exist");
 			return -ENOENT;
 		}
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index c3317ffb09eb..e2ea691e42c6 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -2473,6 +2473,9 @@ static int ip6mr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb)
 
 		mrt = ip6mr_get_table(sock_net(skb->sk), filter.table_id);
 		if (!mrt) {
+			if (filter.dump_all_families)
+				return skb->len;
+
 			NL_SET_ERR_MSG_MOD(cb->extack, "MR table does not exist");
 			return -ENOENT;
 		}
-- 
2.11.0