ipv6: icmp6: add drop reason support to ndisc_router_discovery()

Change ndisc_router_discovery() to return a drop reason.

For the moment, return PKT_TOO_SMALL, NOT_SPECIFIED
and SKB_CONSUMED.

More reasons are added later.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 514eb8c..7c8ba30 100644 (file)
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1231,20 +1231,21 @@ errout:
        rtnl_set_sk_err(net, RTNLGRP_ND_USEROPT, err);
 }
 
-static void ndisc_router_discovery(struct sk_buff *skb)
+static enum skb_drop_reason ndisc_router_discovery(struct sk_buff *skb)
 {
        struct ra_msg *ra_msg = (struct ra_msg *)skb_transport_header(skb);
+       bool send_ifinfo_notify = false;
        struct neighbour *neigh = NULL;
-       struct inet6_dev *in6_dev;
+       struct ndisc_options ndopts;
        struct fib6_info *rt = NULL;
+       struct inet6_dev *in6_dev;
        u32 defrtr_usr_metric;
+       unsigned int pref = 0;
+       __u32 old_if_flags;
        struct net *net;
+       SKB_DR(reason);
        int lifetime;
-       struct ndisc_options ndopts;
        int optlen;
-       unsigned int pref = 0;
-       __u32 old_if_flags;
-       bool send_ifinfo_notify = false;
 
        __u8 *opt = (__u8 *)(ra_msg + 1);
 
@@ -1256,17 +1257,15 @@ static void ndisc_router_discovery(struct sk_buff *skb)
                  __func__, skb->dev->name);
        if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
                ND_PRINTK(2, warn, "RA: source address is not link-local\n");
-               return;
-       }
-       if (optlen < 0) {
-               ND_PRINTK(2, warn, "RA: packet too short\n");
-               return;
+               return reason;
        }
+       if (optlen < 0)
+               return SKB_DROP_REASON_PKT_TOO_SMALL;
 
 #ifdef CONFIG_IPV6_NDISC_NODETYPE
        if (skb->ndisc_nodetype == NDISC_NODETYPE_HOST) {
                ND_PRINTK(2, warn, "RA: from host or unauthorized router\n");
-               return;
+               return reason;
        }
 #endif
 
@@ -1278,12 +1277,12 @@ static void ndisc_router_discovery(struct sk_buff *skb)
        if (!in6_dev) {
                ND_PRINTK(0, err, "RA: can't find inet6 device for %s\n",
                          skb->dev->name);
-               return;
+               return reason;
        }
 
        if (!ndisc_parse_options(skb->dev, opt, optlen, &ndopts)) {
                ND_PRINTK(2, warn, "RA: invalid ND options\n");
-               return;
+               return reason;
        }
 
        if (!ipv6_accept_ra(in6_dev)) {
@@ -1365,7 +1364,7 @@ static void ndisc_router_discovery(struct sk_buff *skb)
                                  "RA: %s got default router without neighbour\n",
                                  __func__);
                        fib6_info_release(rt);
-                       return;
+                       return reason;
                }
        }
        /* Set default route metric as specified by user */
@@ -1390,7 +1389,7 @@ static void ndisc_router_discovery(struct sk_buff *skb)
                        ND_PRINTK(0, err,
                                  "RA: %s failed to add default route\n",
                                  __func__);
-                       return;
+                       return reason;
                }
 
                neigh = ip6_neigh_lookup(&rt->fib6_nh->fib_nh_gw6,
@@ -1401,7 +1400,7 @@ static void ndisc_router_discovery(struct sk_buff *skb)
                                  "RA: %s got default router without neighbour\n",
                                  __func__);
                        fib6_info_release(rt);
-                       return;
+                       return reason;
                }
                neigh->flags |= NTF_ROUTER;
        } else if (rt && IPV6_EXTRACT_PREF(rt->fib6_flags) != pref) {
@@ -1488,6 +1487,7 @@ skip_linkparms:
                             NEIGH_UPDATE_F_OVERRIDE_ISROUTER|
                             NEIGH_UPDATE_F_ISROUTER,
                             NDISC_ROUTER_ADVERTISEMENT, &ndopts);
+               reason = SKB_CONSUMED;
        }
 
        if (!ipv6_accept_ra(in6_dev)) {
@@ -1598,6 +1598,7 @@ out:
        fib6_info_release(rt);
        if (neigh)
                neigh_release(neigh);
+       return reason;
 }
 
 static void ndisc_redirect_rcv(struct sk_buff *skb)
@@ -1850,7 +1851,7 @@ enum skb_drop_reason ndisc_rcv(struct sk_buff *skb)
                break;
 
        case NDISC_ROUTER_ADVERTISEMENT:
-               ndisc_router_discovery(skb);
+               reason = ndisc_router_discovery(skb);
                break;
 
        case NDISC_REDIRECT: