This patch introduces neighbour discovery ops callback structure. The
structure contains at first receive and transmit handling for NS/NA and
userspace option field functionality.

These callback offers 6lowpan different handling, such as 802.15.4 short
address handling or RFC6775 (Neighbor Discovery Optimization for IPv6 over
6LoWPANs).

Cc: David S. Miller <da...@davemloft.net>
Cc: Alexey Kuznetsov <kuz...@ms2.inr.ac.ru>
Cc: James Morris <jmor...@namei.org>
Cc: Hideaki YOSHIFUJI <yoshf...@linux-ipv6.org>
Cc: Patrick McHardy <ka...@trash.net>
Signed-off-by: Alexander Aring <a...@pengutronix.de>
---
 include/linux/netdevice.h |  3 ++
 include/net/ndisc.h       | 73 ++++++++++++++++++++++++++++++++++++++++++-----
 net/ipv6/addrconf.c       |  1 +
 net/ipv6/ndisc.c          | 71 +++++++++++++++++++++++++++++++--------------
 net/ipv6/route.c          |  2 +-
 5 files changed, 121 insertions(+), 29 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 0052c42..4f1b3f2 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1677,6 +1677,9 @@ struct net_device {
 #ifdef CONFIG_NET_L3_MASTER_DEV
        const struct l3mdev_ops *l3mdev_ops;
 #endif
+#ifdef CONFIG_IPV6
+       const struct ndisc_ops *ndisc_ops;
+#endif
 
        const struct header_ops *header_ops;
 
diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index aac868e..5346625 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -110,7 +110,8 @@ struct ndisc_options {
 
 #define NDISC_OPT_SPACE(len) (((len)+2+7)&~7)
 
-struct ndisc_options *ndisc_parse_options(u8 *opt, int opt_len,
+struct ndisc_options *ndisc_parse_options(const struct net_device *dev,
+                                         u8 *opt, int opt_len,
                                          struct ndisc_options *ndopts);
 
 /*
@@ -173,6 +174,70 @@ static inline struct neighbour *__ipv6_neigh_lookup(struct 
net_device *dev, cons
        return n;
 }
 
+static inline int __ip6_ndisc_is_useropt(struct nd_opt_hdr *opt)
+{
+       return opt->nd_opt_type == ND_OPT_RDNSS ||
+               opt->nd_opt_type == ND_OPT_DNSSL;
+}
+
+struct ndisc_ops {
+       int     (*is_useropt)(struct nd_opt_hdr *opt);
+       void    (*send_na)(struct net_device *dev,
+                          const struct in6_addr *daddr,
+                          const struct in6_addr *solicited_addr,
+                          bool router, bool solicited,
+                          bool override, bool inc_opt);
+       void    (*recv_na)(struct sk_buff *skb);
+       void    (*send_ns)(struct net_device *dev,
+                          const struct in6_addr *solicit,
+                          const struct in6_addr *daddr,
+                          const struct in6_addr *saddr);
+       void    (*recv_ns)(struct sk_buff *skb);
+};
+
+static inline int ndisc_is_useropt(const struct net_device *dev,
+                                  struct nd_opt_hdr *opt)
+{
+       if (likely(dev->ndisc_ops->is_useropt))
+               return dev->ndisc_ops->is_useropt(opt);
+       else
+               return 0;
+}
+
+static inline void ndisc_send_na(struct net_device *dev,
+                                const struct in6_addr *daddr,
+                                const struct in6_addr *solicited_addr,
+                                bool router, bool solicited, bool override,
+                                bool inc_opt)
+{
+       if (likely(dev->ndisc_ops->send_na))
+               dev->ndisc_ops->send_na(dev, daddr, solicited_addr, router,
+                                       solicited, override, inc_opt);
+}
+
+static inline void ndisc_recv_na(struct sk_buff *skb)
+{
+       if (likely(skb->dev->ndisc_ops->recv_na))
+               skb->dev->ndisc_ops->recv_na(skb);
+}
+
+static inline void ndisc_send_ns(struct net_device *dev,
+                                const struct in6_addr *solicit,
+                                const struct in6_addr *daddr,
+                                const struct in6_addr *saddr)
+{
+       if (likely(dev->ndisc_ops->send_ns))
+               dev->ndisc_ops->send_ns(dev, solicit, daddr, saddr);
+}
+
+static inline void ndisc_recv_ns(struct sk_buff *skb)
+{
+       if (likely(skb->dev->ndisc_ops->recv_ns))
+               skb->dev->ndisc_ops->recv_ns(skb);
+}
+
+void ip6_register_ndisc_ops(struct net_device *dev);
+
 int ndisc_init(void);
 int ndisc_late_init(void);
 
@@ -181,14 +246,8 @@ void ndisc_cleanup(void);
 
 int ndisc_rcv(struct sk_buff *skb);
 
-void ndisc_send_ns(struct net_device *dev, const struct in6_addr *solicit,
-                  const struct in6_addr *daddr, const struct in6_addr *saddr);
-
 void ndisc_send_rs(struct net_device *dev,
                   const struct in6_addr *saddr, const struct in6_addr *daddr);
-void ndisc_send_na(struct net_device *dev, const struct in6_addr *daddr,
-                  const struct in6_addr *solicited_addr,
-                  bool router, bool solicited, bool override, bool inc_opt);
 
 void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target);
 
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 54e18c2..a2ef04b 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3266,6 +3266,7 @@ static int addrconf_notify(struct notifier_block *this, 
unsigned long event,
                        idev = ipv6_add_dev(dev);
                        if (IS_ERR(idev))
                                return notifier_from_errno(PTR_ERR(idev));
+                       ip6_register_ndisc_ops(dev);
                }
                break;
 
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 176c7c4..297080a 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -185,24 +185,25 @@ static struct nd_opt_hdr *ndisc_next_option(struct 
nd_opt_hdr *cur,
        return cur <= end && cur->nd_opt_type == type ? cur : NULL;
 }
 
-static inline int ndisc_is_useropt(struct nd_opt_hdr *opt)
+static inline int ip6_ndisc_is_useropt(struct nd_opt_hdr *opt)
 {
-       return opt->nd_opt_type == ND_OPT_RDNSS ||
-               opt->nd_opt_type == ND_OPT_DNSSL;
+       return __ip6_ndisc_is_useropt(opt);
 }
 
-static struct nd_opt_hdr *ndisc_next_useropt(struct nd_opt_hdr *cur,
+static struct nd_opt_hdr *ndisc_next_useropt(const struct net_device *dev,
+                                            struct nd_opt_hdr *cur,
                                             struct nd_opt_hdr *end)
 {
        if (!cur || !end || cur >= end)
                return NULL;
        do {
                cur = ((void *)cur) + (cur->nd_opt_len << 3);
-       } while (cur < end && !ndisc_is_useropt(cur));
-       return cur <= end && ndisc_is_useropt(cur) ? cur : NULL;
+       } while (cur < end && !ndisc_is_useropt(dev, cur));
+       return cur <= end && ndisc_is_useropt(dev, cur) ? cur : NULL;
 }
 
-struct ndisc_options *ndisc_parse_options(u8 *opt, int opt_len,
+struct ndisc_options *ndisc_parse_options(const struct net_device *dev,
+                                         u8 *opt, int opt_len,
                                          struct ndisc_options *ndopts)
 {
        struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)opt;
@@ -243,7 +244,7 @@ struct ndisc_options *ndisc_parse_options(u8 *opt, int 
opt_len,
                        break;
 #endif
                default:
-                       if (ndisc_is_useropt(nd_opt)) {
+                       if (ndisc_is_useropt(dev, nd_opt)) {
                                ndopts->nd_useropts_end = nd_opt;
                                if (!ndopts->nd_useropts)
                                        ndopts->nd_useropts = nd_opt;
@@ -479,9 +480,11 @@ static void ndisc_send_skb(struct sk_buff *skb,
        rcu_read_unlock();
 }
 
-void ndisc_send_na(struct net_device *dev, const struct in6_addr *daddr,
-                  const struct in6_addr *solicited_addr,
-                  bool router, bool solicited, bool override, bool inc_opt)
+static void ip6_ndisc_send_na(struct net_device *dev,
+                             const struct in6_addr *daddr,
+                             const struct in6_addr *solicited_addr,
+                             bool router, bool solicited, bool override,
+                             bool inc_opt)
 {
        struct sk_buff *skb;
        struct in6_addr tmpaddr;
@@ -555,8 +558,10 @@ static void ndisc_send_unsol_na(struct net_device *dev)
        in6_dev_put(idev);
 }
 
-void ndisc_send_ns(struct net_device *dev, const struct in6_addr *solicit,
-                  const struct in6_addr *daddr, const struct in6_addr *saddr)
+static void ip6_ndisc_send_ns(struct net_device *dev,
+                             const struct in6_addr *solicit,
+                             const struct in6_addr *daddr,
+                             const struct in6_addr *saddr)
 {
        struct sk_buff *skb;
        struct in6_addr addr_buf;
@@ -702,7 +707,7 @@ static int pndisc_is_router(const void *pkey,
        return ret;
 }
 
-static void ndisc_recv_ns(struct sk_buff *skb)
+static void ip6_ndisc_recv_ns(struct sk_buff *skb)
 {
        struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
        const struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
@@ -738,7 +743,7 @@ static void ndisc_recv_ns(struct sk_buff *skb)
                return;
        }
 
-       if (!ndisc_parse_options(msg->opt, ndoptlen, &ndopts)) {
+       if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts)) {
                ND_PRINTK(2, warn, "NS: invalid ND options\n");
                return;
        }
@@ -874,7 +879,7 @@ out:
                in6_dev_put(idev);
 }
 
-static void ndisc_recv_na(struct sk_buff *skb)
+static void ip6_ndisc_recv_na(struct sk_buff *skb)
 {
        struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
        struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
@@ -912,7 +917,7 @@ static void ndisc_recv_na(struct sk_buff *skb)
            idev->cnf.drop_unsolicited_na)
                return;
 
-       if (!ndisc_parse_options(msg->opt, ndoptlen, &ndopts)) {
+       if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts)) {
                ND_PRINTK(2, warn, "NS: invalid ND option\n");
                return;
        }
@@ -1019,7 +1024,7 @@ static void ndisc_recv_rs(struct sk_buff *skb)
                goto out;
 
        /* Parse ND options */
-       if (!ndisc_parse_options(rs_msg->opt, ndoptlen, &ndopts)) {
+       if (!ndisc_parse_options(skb->dev, rs_msg->opt, ndoptlen, &ndopts)) {
                ND_PRINTK(2, notice, "NS: invalid ND option, ignored\n");
                goto out;
        }
@@ -1137,7 +1142,7 @@ static void ndisc_router_discovery(struct sk_buff *skb)
                return;
        }
 
-       if (!ndisc_parse_options(opt, optlen, &ndopts)) {
+       if (!ndisc_parse_options(skb->dev, opt, optlen, &ndopts)) {
                ND_PRINTK(2, warn, "RA: invalid ND options\n");
                return;
        }
@@ -1424,7 +1429,8 @@ skip_routeinfo:
                struct nd_opt_hdr *p;
                for (p = ndopts.nd_useropts;
                     p;
-                    p = ndisc_next_useropt(p, ndopts.nd_useropts_end)) {
+                    p = ndisc_next_useropt(skb->dev, p,
+                                           ndopts.nd_useropts_end)) {
                        ndisc_ra_useropt(skb, p);
                }
        }
@@ -1462,7 +1468,7 @@ static void ndisc_redirect_rcv(struct sk_buff *skb)
                return;
        }
 
-       if (!ndisc_parse_options(msg->opt, ndoptlen, &ndopts))
+       if (!ndisc_parse_options(skb->dev, msg->opt, ndoptlen, &ndopts))
                return;
 
        if (!ndopts.nd_opts_rh) {
@@ -1783,6 +1789,29 @@ int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl, 
int write, void __user *bu
 
 #endif
 
+static const struct ndisc_ops ip6_ndisc_ops = {
+       .is_useropt = ip6_ndisc_is_useropt,
+       .send_na = ip6_ndisc_send_na,
+       .recv_na = ip6_ndisc_recv_na,
+       .send_ns = ip6_ndisc_send_ns,
+       .recv_ns = ip6_ndisc_recv_ns,
+};
+
+void ip6_register_ndisc_ops(struct net_device *dev)
+{
+       switch (dev->type) {
+       default:
+               if (dev->ndisc_ops) {
+                       ND_PRINTK(2, warn,
+                                 "%s: ndisc_ops already defined for interface 
type=%d\n",
+                                 __func__, dev->type);
+               } else {
+                       dev->ndisc_ops = &ip6_ndisc_ops;
+               }
+               break;
+       }
+}
+
 static int __net_init ndisc_net_init(struct net *net)
 {
        struct ipv6_pinfo *np;
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index cc180b3..5fa276d 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2149,7 +2149,7 @@ static void rt6_do_redirect(struct dst_entry *dst, struct 
sock *sk, struct sk_bu
         *      first-hop router for the specified ICMP Destination Address.
         */
 
-       if (!ndisc_parse_options(msg->opt, optlen, &ndopts)) {
+       if (!ndisc_parse_options(skb->dev, msg->opt, optlen, &ndopts)) {
                net_dbg_ratelimited("rt6_redirect: invalid ND options\n");
                return;
        }
-- 
2.8.0

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