3 files changed, 124 insertions, 9 deletions

diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index dff3192374f8..5bf618241ab9 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -97,6 +97,9 @@ enum {
         RTM_SETNEIGHTBL,
 #define RTM_SETNEIGHTBL RTM_SETNEIGHTBL
 
+        RTM_NEWNDUSEROPT = 68,
+#define RTM_NEWNDUSEROPT RTM_NEWNDUSEROPT
+
         __RTM_MAX,
 #define RTM_MAX         (((__RTM_MAX + 3) & ~3) - 1)
 };
@@ -479,6 +482,30 @@ enum
 #define TCA_RTA(r)  ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct tcmsg))))
 #define TCA_PAYLOAD(n) NLMSG_PAYLOAD(n,sizeof(struct tcmsg))
 
+/********************************************************************
+ *              Neighbor Discovery userland options
+ ****/
+
+struct nduseroptmsg
+{
+        unsigned char   nduseropt_family;
+        unsigned char   nduseropt_pad1;
+        unsigned short  nduseropt_opts_len;     /* Total length of options */
+        __u8            nduseropt_icmp_type;
+        __u8            nduseropt_icmp_code;
+        unsigned short  nduseropt_pad2;
+        /* Followed by one or more ND options */
+};
+
+enum
+{
+        NDUSEROPT_UNSPEC,
+        NDUSEROPT_SRCADDR,
+        __NDUSEROPT_MAX
+};
+
+#define NDUSEROPT_MAX   (__NDUSEROPT_MAX - 1)
+
 #ifndef __KERNEL__
 /* RTnetlink multicast groups - backwards compatibility for userspace */
 #define RTMGRP_LINK             1
@@ -542,6 +569,8 @@ enum rtnetlink_groups {
 #define RTNLGRP_IPV6_PREFIX     RTNLGRP_IPV6_PREFIX
         RTNLGRP_IPV6_RULE,
 #define RTNLGRP_IPV6_RULE       RTNLGRP_IPV6_RULE
+        RTNLGRP_ND_USEROPT,
+#define RTNLGRP_ND_USEROPT      RTNLGRP_ND_USEROPT
         __RTNLGRP_MAX
 };
 #define RTNLGRP_MAX     (__RTNLGRP_MAX - 1)
diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index 475b10c575b3..6684f7efbeeb 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -24,6 +24,7 @@ enum {
         ND_OPT_MTU = 5,                 /* RFC2461 */
         __ND_OPT_ARRAY_MAX,
         ND_OPT_ROUTE_INFO = 24,         /* RFC4191 */
+        ND_OPT_RDNSS = 25,              /* RFC5006 */
         __ND_OPT_MAX
 };
 
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index d4acd283111b..6cc33dc83d1c 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -15,9 +15,10 @@
 /*
  *      Changes:
  *
+ *      Pierre Ynard                    :       export userland ND options
+ *                                              through netlink (RDNSS support)
  *      Lars Fenneberg                  :       fixed MTU setting on receipt
  *                                              of an RA.
- *
  *      Janos Farkas                    :       kmalloc failure checks
  *      Alexey Kuznetsov                :       state machine reworked
  *                                              and moved to net/core.
@@ -78,6 +79,9 @@
 #include <net/addrconf.h>
 #include <net/icmp.h>
 
+#include <net/netlink.h>
+#include <linux/rtnetlink.h>
+
 #include <net/flow.h>
 #include <net/ip6_checksum.h>
 #include <linux/proc_fs.h>
@@ -161,6 +165,8 @@ struct ndisc_options {
         struct nd_opt_hdr *nd_opts_ri;
         struct nd_opt_hdr *nd_opts_ri_end;
 #endif
+        struct nd_opt_hdr *nd_useropts;
+        struct nd_opt_hdr *nd_useropts_end;
 };
 
 #define nd_opts_src_lladdr      nd_opt_array[ND_OPT_SOURCE_LL_ADDR]
@@ -225,6 +231,22 @@ 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)
+{
+        return (opt->nd_opt_type == ND_OPT_RDNSS);
+}
+
+static struct nd_opt_hdr *ndisc_next_useropt(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);
+}
+
 static struct ndisc_options *ndisc_parse_options(u8 *opt, int opt_len,
                                                  struct ndisc_options *ndopts)
 {
@@ -267,14 +289,21 @@ static struct ndisc_options *ndisc_parse_options(u8 *opt, int opt_len,
                         break;
 #endif
                 default:
-                        /*
-                         * Unknown options must be silently ignored,
-                         * to accommodate future extension to the protocol.
-                         */
-                        ND_PRINTK2(KERN_NOTICE
-                                   "%s(): ignored unsupported option; type=%d, len=%d\n",
-                                   __FUNCTION__,
-                                   nd_opt->nd_opt_type, nd_opt->nd_opt_len);
+                        if (ndisc_is_useropt(nd_opt)) {
+                                ndopts->nd_useropts_end = nd_opt;
+                                if (!ndopts->nd_useropts)
+                                        ndopts->nd_useropts = nd_opt;
+                        } else {
+                                /*
+                                 * Unknown options must be silently ignored,
+                                 * to accommodate future extension to the
+                                 * protocol.
+                                 */
+                                ND_PRINTK2(KERN_NOTICE
+                                           "%s(): ignored unsupported option; type=%d, len=%d\n",
+                                           __FUNCTION__,
+                                           nd_opt->nd_opt_type, nd_opt->nd_opt_len);
+                        }
                 }
                 opt_len -= l;
                 nd_opt = ((void *)nd_opt) + l;
@@ -984,6 +1013,53 @@ out:
         in6_dev_put(idev);
 }
 
+static void ndisc_ra_useropt(struct sk_buff *ra, struct nd_opt_hdr *opt)
+{
+        struct icmp6hdr *icmp6h = (struct icmp6hdr *)skb_transport_header(ra);
+        struct sk_buff *skb;
+        struct nlmsghdr *nlh;
+        struct nduseroptmsg *ndmsg;
+        int err;
+        int base_size = NLMSG_ALIGN(sizeof(struct nduseroptmsg)
+                                    + (opt->nd_opt_len << 3));
+        size_t msg_size = base_size + nla_total_size(sizeof(struct in6_addr));
+
+        skb = nlmsg_new(msg_size, GFP_ATOMIC);
+        if (skb == NULL) {
+                err = -ENOBUFS;
+                goto errout;
+        }
+
+        nlh = nlmsg_put(skb, 0, 0, RTM_NEWNDUSEROPT, base_size, 0);
+        if (nlh == NULL) {
+                goto nla_put_failure;
+        }
+
+        ndmsg = nlmsg_data(nlh);
+        ndmsg->nduseropt_family = AF_INET6;
+        ndmsg->nduseropt_icmp_type = icmp6h->icmp6_type;
+        ndmsg->nduseropt_icmp_code = icmp6h->icmp6_code;
+        ndmsg->nduseropt_opts_len = opt->nd_opt_len << 3;
+
+        memcpy(ndmsg + 1, opt, opt->nd_opt_len << 3);
+
+        NLA_PUT(skb, NDUSEROPT_SRCADDR, sizeof(struct in6_addr),
+                &ipv6_hdr(ra)->saddr);
+        nlmsg_end(skb, nlh);
+
+        err = rtnl_notify(skb, 0, RTNLGRP_ND_USEROPT, NULL, GFP_ATOMIC);
+        if (err < 0)
+                goto errout;
+
+        return;
+
+nla_put_failure:
+        nlmsg_free(skb);
+        err = -EMSGSIZE;
+errout:
+        rtnl_set_sk_err(RTNLGRP_ND_USEROPT, err);
+}
+
 static void ndisc_router_discovery(struct sk_buff *skb)
 {
         struct ra_msg *ra_msg = (struct ra_msg *)skb_transport_header(skb);
@@ -1216,6 +1292,15 @@ skip_defrtr:
                 }
         }
 
+        if (ndopts.nd_useropts) {
+                struct nd_opt_hdr *opt;
+                for (opt = ndopts.nd_useropts;
+                     opt;
+                     opt = ndisc_next_useropt(opt, ndopts.nd_useropts_end)) {
+                                ndisc_ra_useropt(skb, opt);
+                }
+        }
+
         if (ndopts.nd_opts_tgt_lladdr || ndopts.nd_opts_rh) {
                 ND_PRINTK2(KERN_WARNING
                            "ICMPv6 RA: invalid RA options");