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

[Jiri Pirko <jiri@resnulli.us>]

Tue, Mar 03, 2015 at 11:01:52AM CET, lkundrak@v3.sk wrote:
>This makes it possible to retain the route preference when RAs are handled in
>userspace.
>
>Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
>---
> 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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