In inet6_rtm_getroute, since Commit 93531c674315 ("net/ipv6: separate
handling of FIB entries from dst based routes"), it has used rt->from
to dump route info instead of rt.

However for some route like cache, its information is not the same as
that of the 'from' one. It caused 'ip -6 route get' to dump the wrong
route information.

In Jianlin's testing, the output information even lost the expiration
time for a pmtu route cache due to the wrong fib6_flags.

So change to use rt6_info members when it tries to dump a route entry
without fibmatch set.

Note that we will fix the gw/nh dump in another patch.

Fixes: 93531c674315 ("net/ipv6: separate handling of FIB entries from dst based 
routes")
Reported-by: Jianlin Shi <ji...@redhat.com>
Signed-off-by: Xin Long <lucien....@gmail.com>
---
 net/ipv6/route.c | 39 ++++++++++++++++++++++++++-------------
 1 file changed, 26 insertions(+), 13 deletions(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 18e00ce..e554922 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -4670,20 +4670,33 @@ static int rt6_fill_node(struct net *net, struct 
sk_buff *skb,
                         int iif, int type, u32 portid, u32 seq,
                         unsigned int flags)
 {
-       struct rtmsg *rtm;
+       struct rt6key *fib6_prefsrc, *fib6_dst, *fib6_src;
+       struct rt6_info *rt6 = (struct rt6_info *)dst;
+       u32 *pmetrics, table, fib6_flags;
        struct nlmsghdr *nlh;
+       struct rtmsg *rtm;
        long expires = 0;
-       u32 *pmetrics;
-       u32 table;
 
        nlh = nlmsg_put(skb, portid, seq, type, sizeof(*rtm), flags);
        if (!nlh)
                return -EMSGSIZE;
 
+       if (rt6) {
+               fib6_dst = &rt6->rt6i_dst;
+               fib6_src = &rt6->rt6i_src;
+               fib6_flags = rt6->rt6i_flags;
+               fib6_prefsrc = &rt6->rt6i_prefsrc;
+       } else {
+               fib6_dst = &rt->fib6_dst;
+               fib6_src = &rt->fib6_src;
+               fib6_flags = rt->fib6_flags;
+               fib6_prefsrc = &rt->fib6_prefsrc;
+       }
+
        rtm = nlmsg_data(nlh);
        rtm->rtm_family = AF_INET6;
-       rtm->rtm_dst_len = rt->fib6_dst.plen;
-       rtm->rtm_src_len = rt->fib6_src.plen;
+       rtm->rtm_dst_len = fib6_dst->plen;
+       rtm->rtm_src_len = fib6_src->plen;
        rtm->rtm_tos = 0;
        if (rt->fib6_table)
                table = rt->fib6_table->tb6_id;
@@ -4698,7 +4711,7 @@ static int rt6_fill_node(struct net *net, struct sk_buff 
*skb,
        rtm->rtm_scope = RT_SCOPE_UNIVERSE;
        rtm->rtm_protocol = rt->fib6_protocol;
 
-       if (rt->fib6_flags & RTF_CACHE)
+       if (fib6_flags & RTF_CACHE)
                rtm->rtm_flags |= RTM_F_CLONED;
 
        if (dest) {
@@ -4706,7 +4719,7 @@ static int rt6_fill_node(struct net *net, struct sk_buff 
*skb,
                        goto nla_put_failure;
                rtm->rtm_dst_len = 128;
        } else if (rtm->rtm_dst_len)
-               if (nla_put_in6_addr(skb, RTA_DST, &rt->fib6_dst.addr))
+               if (nla_put_in6_addr(skb, RTA_DST, &fib6_dst->addr))
                        goto nla_put_failure;
 #ifdef CONFIG_IPV6_SUBTREES
        if (src) {
@@ -4714,12 +4727,12 @@ static int rt6_fill_node(struct net *net, struct 
sk_buff *skb,
                        goto nla_put_failure;
                rtm->rtm_src_len = 128;
        } else if (rtm->rtm_src_len &&
-                  nla_put_in6_addr(skb, RTA_SRC, &rt->fib6_src.addr))
+                  nla_put_in6_addr(skb, RTA_SRC, &fib6_src->addr))
                goto nla_put_failure;
 #endif
        if (iif) {
 #ifdef CONFIG_IPV6_MROUTE
-               if (ipv6_addr_is_multicast(&rt->fib6_dst.addr)) {
+               if (ipv6_addr_is_multicast(&fib6_dst->addr)) {
                        int err = ip6mr_get_route(net, skb, rtm, portid);
 
                        if (err == 0)
@@ -4737,9 +4750,9 @@ static int rt6_fill_node(struct net *net, struct sk_buff 
*skb,
                        goto nla_put_failure;
        }
 
-       if (rt->fib6_prefsrc.plen) {
+       if (fib6_prefsrc->plen) {
                struct in6_addr saddr_buf;
-               saddr_buf = rt->fib6_prefsrc.addr;
+               saddr_buf = fib6_prefsrc->addr;
                if (nla_put_in6_addr(skb, RTA_PREFSRC, &saddr_buf))
                        goto nla_put_failure;
        }
@@ -4777,7 +4790,7 @@ static int rt6_fill_node(struct net *net, struct sk_buff 
*skb,
                        goto nla_put_failure;
        }
 
-       if (rt->fib6_flags & RTF_EXPIRES) {
+       if (fib6_flags & RTF_EXPIRES) {
                expires = dst ? dst->expires : rt->expires;
                expires -= jiffies;
        }
@@ -4785,7 +4798,7 @@ static int rt6_fill_node(struct net *net, struct sk_buff 
*skb,
        if (rtnl_put_cacheinfo(skb, dst, 0, expires, dst ? dst->error : 0) < 0)
                goto nla_put_failure;
 
-       if (nla_put_u8(skb, RTA_PREF, IPV6_EXTRACT_PREF(rt->fib6_flags)))
+       if (nla_put_u8(skb, RTA_PREF, IPV6_EXTRACT_PREF(fib6_flags)))
                goto nla_put_failure;
 
 
-- 
2.1.0

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