Re: [PATCH] ipv6: expose RFC4191 route preference via rtnetlink

From: Jiri Pirko
Date: Tue Mar 03 2015 - 10:17:24 EST


Tue, Mar 03, 2015 at 11:01:52AM CET, lkundrak@xxxxx wrote:
>This makes it possible to retain the route preference when RAs are handled in
>userspace.
>
>Signed-off-by: Lubomir Rintel <lkundrak@xxxxx>
>---
> include/uapi/linux/rtnetlink.h | 1 +
> net/ipv6/route.c | 16 +++++++++++++++-
> 2 files changed, 16 insertions(+), 1 deletion(-)
>
>diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
>index 5cc5d66..0671524 100644
>--- a/include/uapi/linux/rtnetlink.h
>+++ b/include/uapi/linux/rtnetlink.h
>@@ -303,6 +303,7 @@ enum rtattr_type_t {
> RTA_TABLE,
> RTA_MARK,
> RTA_MFC_STATS,
>+ RTA_PREF,
> __RTA_MAX
> };
>
>diff --git a/net/ipv6/route.c b/net/ipv6/route.c
>index 47b5109..08f689e 100644
>--- a/net/ipv6/route.c
>+++ b/net/ipv6/route.c
>@@ -2401,6 +2401,7 @@ static const struct nla_policy rtm_ipv6_policy[RTA_MAX+1] = {
> [RTA_PRIORITY] = { .type = NLA_U32 },
> [RTA_METRICS] = { .type = NLA_NESTED },
> [RTA_MULTIPATH] = { .len = sizeof(struct rtnexthop) },
>+ [RTA_PREF] = { .type = NLA_U8 },
> };
>
> static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
>@@ -2408,6 +2409,7 @@ static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
> {
> struct rtmsg *rtm;
> struct nlattr *tb[RTA_MAX+1];
>+ unsigned int pref;
> int err;
>
> err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv6_policy);
>@@ -2483,6 +2485,14 @@ static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
> cfg->fc_mp_len = nla_len(tb[RTA_MULTIPATH]);
> }
>
>+ if (tb[RTA_PREF]) {
>+ pref = nla_get_u8(tb[RTA_PREF]);
>+ if (pref == ICMPV6_ROUTER_PREF_LOW ||
>+ pref == ICMPV6_ROUTER_PREF_MEDIUM ||
>+ pref == ICMPV6_ROUTER_PREF_HIGH)
>+ cfg->fc_flags |= RTF_PREF(pref);

Don't we want to do "goto errout;" in case pref is invalid ?


>+ }
>+
> err = 0;
> errout:
> return err;
>@@ -2586,7 +2596,8 @@ static inline size_t rt6_nlmsg_size(void)
> + nla_total_size(4) /* RTA_PRIORITY */
> + RTAX_MAX * nla_total_size(4) /* RTA_METRICS */
> + nla_total_size(sizeof(struct rta_cacheinfo))
>- + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
>+ + nla_total_size(TCP_CA_NAME_MAX) /* RTAX_CC_ALGO */
>+ + nla_total_size(1); /* RTA_PREF */
> }
>
> static int rt6_fill_node(struct net *net,
>@@ -2727,6 +2738,9 @@ static int rt6_fill_node(struct net *net,
> if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, rt->dst.error) < 0)
> goto nla_put_failure;
>
>+ if (nla_put_u8(skb, RTA_PREF, IPV6_EXTRACT_PREF(rt->rt6i_flags)))
>+ goto nla_put_failure;
>+
> nlmsg_end(skb, nlh);
> return 0;
>
>--
>2.1.0
>
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