On 20.04.2016 10:19, Alexander Aring wrote:
> 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 | 96
> +++++++++++++++++++++++++++++++++++++++++++----
> net/ipv6/addrconf.c | 1 +
> net/ipv6/ndisc.c | 71 ++++++++++++++++++++++++-----------
> net/ipv6/route.c | 2 +-
> 5 files changed, 144 insertions(+), 29 deletions(-)
>
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 0052c42..bc60033 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
> +#if IS_ENABLED(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..14ed016 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 +174,93 @@ 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;
> +}
> +
> +#if IS_ENABLED(CONFIG_IPV6)
> +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);
> +}
> +#else
> +static inline int ndisc_is_useropt(const struct net_device *dev,
> + struct nd_opt_hdr *opt)
> +{
> + 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) { }
> +
> +static inline void ndisc_recv_na(struct sk_buff *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) { }
> +
> +static inline void ndisc_recv_ns(struct sk_buff *skb) { }
> +#endif
Do those empty functions actually make sense? I wonder a bit because
6lowpan strictly depends on ipv6 and they should never be called without
IPv6, no?
> +
> +void ip6_register_ndisc_ops(struct net_device *dev);
> +
> int ndisc_init(void);
> int ndisc_late_init(void);
>
> @@ -181,14 +269,8 @@ 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);
Is it possible to register the ndisc options before we make the device
visible to the stack? Maybe even as a pointer to ipv6_add_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);
> }
inline in C functions are not necessary.
>
> -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;
I would be more stricht with validation:
if (!WARN_ON(dev->ndisc_ops))
dev->ndisc_ops = &ip6_ndisc_ops;
> + }
> +}
> +
> 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;
> }
>
