ipv6: Allow routes to use nexthop objects

Add support for RTA_NH_ID attribute to allow a user to specify a
nexthop id to use with a route. fc_nh_id is added to fib6_config to
hold the value passed in the RTA_NH_ID attribute. If a nexthop id
is given, the gateway, device, encap and multipath attributes can
not be set.

Update ip6_route_del to check metric and protocol before nexthop
specs. If fc_nh_id is set, then it must match the id in the route
entry. Since IPv6 allows delete of a cached entry (an exception),
add ip6_del_cached_rt_nh to cycle through all of the fib6_nh in
a fib entry if it is using a nexthop.

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

diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index ac0427c..1e92f15 100644 (file)
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -49,6 +49,7 @@ struct fib6_config {
        u16             fc_delete_all_nh : 1,
                        fc_ignore_dev_down:1,
                        __unused : 14;
+       u32             fc_nh_id;
 
        struct in6_addr fc_dst;
        struct in6_addr fc_src;

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index f287375..f7257a5 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3531,6 +3531,16 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
                goto out;
        }
 #endif
+       if (cfg->fc_nh_id) {
+               nh = nexthop_find_by_id(net, cfg->fc_nh_id);
+               if (!nh) {
+                       NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
+                       goto out;
+               }
+               err = fib6_check_nexthop(nh, cfg, extack);
+               if (err)
+                       goto out;
+       }
 
        err = -ENOBUFS;
        if (cfg->fc_nlinfo.nlh &&
@@ -3762,6 +3772,30 @@ static int ip6_del_cached_rt(struct fib6_config *cfg, struct fib6_info *rt,
        return 0;
 }
 
+struct fib6_nh_del_cached_rt_arg {
+       struct fib6_config *cfg;
+       struct fib6_info *f6i;
+};
+
+static int fib6_nh_del_cached_rt(struct fib6_nh *nh, void *_arg)
+{
+       struct fib6_nh_del_cached_rt_arg *arg = _arg;
+       int rc;
+
+       rc = ip6_del_cached_rt(arg->cfg, arg->f6i, nh);
+       return rc != -ESRCH ? rc : 0;
+}
+
+static int ip6_del_cached_rt_nh(struct fib6_config *cfg, struct fib6_info *f6i)
+{
+       struct fib6_nh_del_cached_rt_arg arg = {
+               .cfg = cfg,
+               .f6i = f6i
+       };
+
+       return nexthop_for_each_fib6_nh(f6i->nh, fib6_nh_del_cached_rt, &arg);
+}
+
 static int ip6_route_del(struct fib6_config *cfg,
                         struct netlink_ext_ack *extack)
 {
@@ -3787,11 +3821,20 @@ static int ip6_route_del(struct fib6_config *cfg,
                for_each_fib6_node_rt_rcu(fn) {
                        struct fib6_nh *nh;
 
-                       nh = rt->fib6_nh;
-                       if (cfg->fc_flags & RTF_CACHE) {
-                               int rc;
+                       if (rt->nh && rt->nh->id != cfg->fc_nh_id)
+                               continue;
 
-                               rc = ip6_del_cached_rt(cfg, rt, nh);
+                       if (cfg->fc_flags & RTF_CACHE) {
+                               int rc = 0;
+
+                               if (rt->nh) {
+                                       rc = ip6_del_cached_rt_nh(cfg, rt);
+                               } else if (cfg->fc_nh_id) {
+                                       continue;
+                               } else {
+                                       nh = rt->fib6_nh;
+                                       rc = ip6_del_cached_rt(cfg, rt, nh);
+                               }
                                if (rc != -ESRCH) {
                                        rcu_read_unlock();
                                        return rc;
@@ -3799,6 +3842,23 @@ static int ip6_route_del(struct fib6_config *cfg,
                                continue;
                        }
 
+                       if (cfg->fc_metric && cfg->fc_metric != rt->fib6_metric)
+                               continue;
+                       if (cfg->fc_protocol &&
+                           cfg->fc_protocol != rt->fib6_protocol)
+                               continue;
+
+                       if (rt->nh) {
+                               if (!fib6_info_hold_safe(rt))
+                                       continue;
+                               rcu_read_unlock();
+
+                               return __ip6_del_rt(rt, &cfg->fc_nlinfo);
+                       }
+                       if (cfg->fc_nh_id)
+                               continue;
+
+                       nh = rt->fib6_nh;
                        if (cfg->fc_ifindex &&
                            (!nh->fib_nh_dev ||
                             nh->fib_nh_dev->ifindex != cfg->fc_ifindex))
@@ -3806,10 +3866,6 @@ static int ip6_route_del(struct fib6_config *cfg,
                        if (cfg->fc_flags & RTF_GATEWAY &&
                            !ipv6_addr_equal(&cfg->fc_gateway, &nh->fib_nh_gw6))
                                continue;
-                       if (cfg->fc_metric && cfg->fc_metric != rt->fib6_metric)
-                               continue;
-                       if (cfg->fc_protocol && cfg->fc_protocol != rt->fib6_protocol)
-                               continue;
                        if (!fib6_info_hold_safe(rt))
                                continue;
                        rcu_read_unlock();
@@ -4709,6 +4765,7 @@ static const struct nla_policy rtm_ipv6_policy[RTA_MAX+1] = {
        [RTA_IP_PROTO]          = { .type = NLA_U8 },
        [RTA_SPORT]             = { .type = NLA_U16 },
        [RTA_DPORT]             = { .type = NLA_U16 },
+       [RTA_NH_ID]             = { .type = NLA_U32 },
 };
 
 static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
@@ -4755,6 +4812,16 @@ static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
 
        cfg->fc_flags |= (rtm->rtm_flags & RTNH_F_ONLINK);
 
+       if (tb[RTA_NH_ID]) {
+               if (tb[RTA_GATEWAY]   || tb[RTA_OIF] ||
+                   tb[RTA_MULTIPATH] || tb[RTA_ENCAP]) {
+                       NL_SET_ERR_MSG(extack,
+                                      "Nexthop specification and nexthop id are mutually exclusive");
+                       goto errout;
+               }
+               cfg->fc_nh_id = nla_get_u32(tb[RTA_NH_ID]);
+       }
+
        if (tb[RTA_GATEWAY]) {
                cfg->fc_gateway = nla_get_in6_addr(tb[RTA_GATEWAY]);
                cfg->fc_flags |= RTF_GATEWAY;
@@ -5089,6 +5156,12 @@ static int inet6_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
        if (err < 0)
                return err;
 
+       if (cfg.fc_nh_id &&
+           !nexthop_find_by_id(sock_net(skb->sk), cfg.fc_nh_id)) {
+               NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
+               return -EINVAL;
+       }
+
        if (cfg.fc_mp)
                return ip6_route_multipath_del(&cfg, extack);
        else {