inet: allow ip_valid_fib_dump_req() to be called with RTNL or RCU

Add a new field into struct fib_dump_filter, to let callers
tell if they use RTNL locking or RCU.

This is used in the following patch, when inet_dump_fib()
no longer holds RTNL.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index d4667b7797e3e4591f3ff1fe641f168295e0a894..9b2f69ba5e4981fb108581c229ff008d04750ade 100644 (file)
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -264,6 +264,7 @@ struct fib_dump_filter {
        bool                    filter_set;
        bool                    dump_routes;
        bool                    dump_exceptions;
+       bool                    rtnl_held;
        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 390f4be7f7bec20f33aa80e9bf12d5e2f3760562..39f67990e01c19b73a622dced0220a1bba21d5e6 100644 (file)
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -916,7 +916,8 @@ int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
        struct rtmsg *rtm;
        int err, i;
 
-       ASSERT_RTNL();
+       if (filter->rtnl_held)
+               ASSERT_RTNL();
 
        if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
                NL_SET_ERR_MSG(extack, "Invalid header for FIB dump request");
@@ -961,7 +962,10 @@ int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
                        break;
                case RTA_OIF:
                        ifindex = nla_get_u32(tb[i]);
-                       filter->dev = __dev_get_by_index(net, ifindex);
+                       if (filter->rtnl_held)
+                               filter->dev = __dev_get_by_index(net, ifindex);
+                       else
+                               filter->dev = dev_get_by_index_rcu(net, ifindex);
                        if (!filter->dev)
                                return -ENODEV;
                        break;
@@ -983,8 +987,11 @@ EXPORT_SYMBOL_GPL(ip_valid_fib_dump_req);
 
 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 {
-       struct fib_dump_filter filter = { .dump_routes = true,
-                                         .dump_exceptions = true };
+       struct fib_dump_filter filter = {
+               .dump_routes = true,
+               .dump_exceptions = true,
+               .rtnl_held = true,
+       };
        const struct nlmsghdr *nlh = cb->nlh;
        struct net *net = sock_net(skb->sk);
        unsigned int h, s_h;

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 5561bce3a37e8f72d08ff8062d6b8cde08bbed44..0708ac6f6c582681ab1f2b52c5ce1f2a4acd10de 100644 (file)
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -2587,7 +2587,9 @@ errout_free:
 
 static int ipmr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb)
 {
-       struct fib_dump_filter filter = {};
+       struct fib_dump_filter filter = {
+               .rtnl_held = true,
+       };
        int err;
 
        if (cb->strict_check) {

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 6540d877d3693e788d000309950f3735554c937d..5c558dc1c6838681c2848412dced72a41fe764be 100644 (file)
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -620,8 +620,11 @@ static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
 
 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 {
-       struct rt6_rtnl_dump_arg arg = { .filter.dump_exceptions = true,
-                                        .filter.dump_routes = true };
+       struct rt6_rtnl_dump_arg arg = {
+               .filter.dump_exceptions = true,
+               .filter.dump_routes = true,
+               .filter.rtnl_held = true,
+       };
        const struct nlmsghdr *nlh = cb->nlh;
        struct net *net = sock_net(skb->sk);
        unsigned int h, s_h;

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 1f19743f254064852139809143b60c1d397fe1d8..cb0ee81a068a4c895d5d8b21f3fc557bf1784dfb 100644 (file)
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -2592,7 +2592,9 @@ static int ip6mr_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 static int ip6mr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb)
 {
        const struct nlmsghdr *nlh = cb->nlh;
-       struct fib_dump_filter filter = {};
+       struct fib_dump_filter filter = {
+               .rtnl_held = true,
+       };
        int err;
 
        if (cb->strict_check) {

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 1af29af65388584e9666f4fcb73a16e8ff159587..6dab883a08dda46ff6ddc1e6e407e6f48a10c8aa 100644 (file)
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -2179,7 +2179,9 @@ static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)
        const struct nlmsghdr *nlh = cb->nlh;
        struct net *net = sock_net(skb->sk);
        struct mpls_route __rcu **platform_label;
-       struct fib_dump_filter filter = {};
+       struct fib_dump_filter filter = {
+               .rtnl_held = true,
+       };
        unsigned int flags = NLM_F_MULTI;
        size_t platform_labels;
        unsigned int index;