net: ipv4: refactor ip_route_input_noref

A later patch wants access to the fib result on an input route lookup
with the rcu lock held. Refactor ip_route_input_noref pushing the logic
between rcu_read_lock ... rcu_read_unlock into a new helper that takes
the fib_result as an input arg.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/route.h b/include/net/route.h
index 89e4028..08e689f 100644 (file)
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -178,6 +178,9 @@ static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4
 
 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
                         u8 tos, struct net_device *devin);
+int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src,
+                      u8 tos, struct net_device *devin,
+                      struct fib_result *res);
 
 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
                                 u8 tos, struct net_device *devin)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index c9b55cb..1dc8fd1 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1852,9 +1852,9 @@ static int ip_mkroute_input(struct sk_buff *skb,
  */
 
 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
-                              u8 tos, struct net_device *dev)
+                              u8 tos, struct net_device *dev,
+                              struct fib_result *res)
 {
-       struct fib_result res;
        struct in_device *in_dev = __in_dev_get_rcu(dev);
        struct ip_tunnel_info *tun_info;
        struct flowi4   fl4;
@@ -1884,8 +1884,8 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
        if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
                goto martian_source;
 
-       res.fi = NULL;
-       res.table = NULL;
+       res->fi = NULL;
+       res->table = NULL;
        if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
                goto brd_input;
 
@@ -1921,17 +1921,17 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
        fl4.daddr = daddr;
        fl4.saddr = saddr;
        fl4.flowi4_uid = sock_net_uid(net, NULL);
-       err = fib_lookup(net, &fl4, &res, 0);
+       err = fib_lookup(net, &fl4, res, 0);
        if (err != 0) {
                if (!IN_DEV_FORWARD(in_dev))
                        err = -EHOSTUNREACH;
                goto no_route;
        }
 
-       if (res.type == RTN_BROADCAST)
+       if (res->type == RTN_BROADCAST)
                goto brd_input;
 
-       if (res.type == RTN_LOCAL) {
+       if (res->type == RTN_LOCAL) {
                err = fib_validate_source(skb, saddr, daddr, tos,
                                          0, dev, in_dev, &itag);
                if (err < 0)
@@ -1943,10 +1943,10 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
                err = -EHOSTUNREACH;
                goto no_route;
        }
-       if (res.type != RTN_UNICAST)
+       if (res->type != RTN_UNICAST)
                goto martian_destination;
 
-       err = ip_mkroute_input(skb, &res, in_dev, daddr, saddr, tos);
+       err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos);
 out:   return err;
 
 brd_input:
@@ -1960,14 +1960,14 @@ brd_input:
                        goto martian_source;
        }
        flags |= RTCF_BROADCAST;
-       res.type = RTN_BROADCAST;
+       res->type = RTN_BROADCAST;
        RT_CACHE_STAT_INC(in_brd);
 
 local_input:
        do_cache = false;
-       if (res.fi) {
+       if (res->fi) {
                if (!itag) {
-                       rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
+                       rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
                        if (rt_cache_valid(rth)) {
                                skb_dst_set_noref(skb, &rth->dst);
                                err = 0;
@@ -1978,7 +1978,7 @@ local_input:
        }
 
        rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
-                          flags | RTCF_LOCAL, res.type,
+                          flags | RTCF_LOCAL, res->type,
                           IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
        if (!rth)
                goto e_nobufs;
@@ -1988,18 +1988,18 @@ local_input:
        rth->dst.tclassid = itag;
 #endif
        rth->rt_is_input = 1;
-       if (res.table)
-               rth->rt_table_id = res.table->tb_id;
+       if (res->table)
+               rth->rt_table_id = res->table->tb_id;
 
        RT_CACHE_STAT_INC(in_slow_tot);
-       if (res.type == RTN_UNREACHABLE) {
+       if (res->type == RTN_UNREACHABLE) {
                rth->dst.input= ip_error;
                rth->dst.error= -err;
                rth->rt_flags   &= ~RTCF_LOCAL;
        }
 
        if (do_cache) {
-               struct fib_nh *nh = &FIB_RES_NH(res);
+               struct fib_nh *nh = &FIB_RES_NH(*res);
 
                rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
                if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
@@ -2019,9 +2019,9 @@ local_input:
 
 no_route:
        RT_CACHE_STAT_INC(in_no_route);
-       res.type = RTN_UNREACHABLE;
-       res.fi = NULL;
-       res.table = NULL;
+       res->type = RTN_UNREACHABLE;
+       res->fi = NULL;
+       res->table = NULL;
        goto local_input;
 
        /*
@@ -2051,11 +2051,22 @@ martian_source:
 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
                         u8 tos, struct net_device *dev)
 {
-       int res;
+       struct fib_result res;
+       int err;
 
        tos &= IPTOS_RT_MASK;
        rcu_read_lock();
+       err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
+       rcu_read_unlock();
 
+       return err;
+}
+EXPORT_SYMBOL(ip_route_input_noref);
+
+/* called with rcu_read_lock held */
+int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
+                      u8 tos, struct net_device *dev, struct fib_result *res)
+{
        /* Multicast recognition logic is moved from route cache to here.
           The problem was that too many Ethernet cards have broken/missing
           hardware multicast filters :-( As result the host on multicasting
@@ -2070,6 +2081,7 @@ int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
        if (ipv4_is_multicast(daddr)) {
                struct in_device *in_dev = __in_dev_get_rcu(dev);
                int our = 0;
+               int err = -EINVAL;
 
                if (in_dev)
                        our = ip_check_mc_rcu(in_dev, daddr, saddr,
@@ -2085,7 +2097,6 @@ int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
                                                      ip_hdr(skb)->protocol);
                }
 
-               res = -EINVAL;
                if (our
 #ifdef CONFIG_IP_MROUTE
                        ||
@@ -2093,17 +2104,14 @@ int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
                     IN_DEV_MFORWARD(in_dev))
 #endif
                   ) {
-                       res = ip_route_input_mc(skb, daddr, saddr,
+                       err = ip_route_input_mc(skb, daddr, saddr,
                                                tos, dev, our);
                }
-               rcu_read_unlock();
-               return res;
+               return err;
        }
-       res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
-       rcu_read_unlock();
-       return res;
+
+       return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
 }
-EXPORT_SYMBOL(ip_route_input_noref);
 
 /* called with rcu_read_lock() */
 static struct rtable *__mkroute_output(const struct fib_result *res,