net: neighbour: Add mcast_resolicit to configure the number of multicast resolicitati...

We send unicast neighbor (ARP or NDP) solicitations ucast_probes
times in PROBE state.  Zhu Yanjun reported that some implementation
does not reply against them and the entry will become FAILED, which
is undesirable.

We had been dealt with such nodes by sending multicast probes mcast_
solicit times after unicast probes in PROBE state.  In 2003, I made
a change not to send them to improve compatibility with IPv6 NDP.

Let's introduce per-protocol per-interface sysctl knob "mcast_
reprobe" to configure the number of multicast (re)solicitation for
reconfirmation in PROBE state.  The default is 0, since we have
been doing so for 10+ years.

Reported-by: Zhu Yanjun <Yanjun.Zhu@windriver.com>
CC: Ulf Samuelsson <ulf.samuelsson@ericsson.com>
Signed-off-by: YOSHIFUJI Hideaki <hideaki.yoshifuji@miraclelinux.com>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index e7bdf517080231469d1f86f2e737fe32a32c636c..bd33e66f49aad086784b2dd66cb054ea18e73c7a 100644 (file)
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -42,6 +42,7 @@ enum {
        NEIGH_VAR_MCAST_PROBES,
        NEIGH_VAR_UCAST_PROBES,
        NEIGH_VAR_APP_PROBES,
+       NEIGH_VAR_MCAST_REPROBES,
        NEIGH_VAR_RETRANS_TIME,
        NEIGH_VAR_BASE_REACHABLE_TIME,
        NEIGH_VAR_DELAY_PROBE_TIME,

diff --git a/include/uapi/linux/neighbour.h b/include/uapi/linux/neighbour.h
index 3873a35509aad201f4d5ddb31346077a89641b78..2e35c61bbdd192eb08c8dbe787f179cd62b9aaad 100644 (file)
--- a/include/uapi/linux/neighbour.h
+++ b/include/uapi/linux/neighbour.h
@@ -126,6 +126,7 @@ enum {
        NDTPA_PROXY_QLEN,               /* u32 */
        NDTPA_LOCKTIME,                 /* u64, msecs */
        NDTPA_QUEUE_LENBYTES,           /* u32 */
+       NDTPA_MCAST_REPROBES,           /* u32 */
        __NDTPA_MAX
 };
 #define NDTPA_MAX (__NDTPA_MAX - 1)

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 0e8b32efc0316c85e56c4b7a95c4c903fde63ecf..3de6542560288b3896ab243879a7b4a9b098ca0d 100644 (file)
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -817,10 +817,9 @@ out:
 static __inline__ int neigh_max_probes(struct neighbour *n)
 {
        struct neigh_parms *p = n->parms;
-       int max_probes = NEIGH_VAR(p, UCAST_PROBES) + NEIGH_VAR(p, APP_PROBES);
-       if (!(n->nud_state & NUD_PROBE))
-               max_probes += NEIGH_VAR(p, MCAST_PROBES);
-       return max_probes;
+       return NEIGH_VAR(p, UCAST_PROBES) + NEIGH_VAR(p, APP_PROBES) +
+              (n->nud_state & NUD_PROBE ? NEIGH_VAR(p, MCAST_REPROBES) :
+               NEIGH_VAR(p, MCAST_PROBES));
 }
 
 static void neigh_invalidate(struct neighbour *neigh)
@@ -1742,6 +1741,8 @@ static int neightbl_fill_parms(struct sk_buff *skb, struct neigh_parms *parms)
                        NEIGH_VAR(parms, UCAST_PROBES)) ||
            nla_put_u32(skb, NDTPA_MCAST_PROBES,
                        NEIGH_VAR(parms, MCAST_PROBES)) ||
+           nla_put_u32(skb, NDTPA_MCAST_REPROBES,
+                       NEIGH_VAR(parms, MCAST_REPROBES)) ||
            nla_put_msecs(skb, NDTPA_REACHABLE_TIME, parms->reachable_time) ||
            nla_put_msecs(skb, NDTPA_BASE_REACHABLE_TIME,
                          NEIGH_VAR(parms, BASE_REACHABLE_TIME)) ||
@@ -1901,6 +1902,7 @@ static const struct nla_policy nl_ntbl_parm_policy[NDTPA_MAX+1] = {
        [NDTPA_APP_PROBES]              = { .type = NLA_U32 },
        [NDTPA_UCAST_PROBES]            = { .type = NLA_U32 },
        [NDTPA_MCAST_PROBES]            = { .type = NLA_U32 },
+       [NDTPA_MCAST_REPROBES]          = { .type = NLA_U32 },
        [NDTPA_BASE_REACHABLE_TIME]     = { .type = NLA_U64 },
        [NDTPA_GC_STALETIME]            = { .type = NLA_U64 },
        [NDTPA_DELAY_PROBE_TIME]        = { .type = NLA_U64 },
@@ -2001,6 +2003,10 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh)
                                NEIGH_VAR_SET(p, MCAST_PROBES,
                                              nla_get_u32(tbp[i]));
                                break;
+                       case NDTPA_MCAST_REPROBES:
+                               NEIGH_VAR_SET(p, MCAST_REPROBES,
+                                             nla_get_u32(tbp[i]));
+                               break;
                        case NDTPA_BASE_REACHABLE_TIME:
                                NEIGH_VAR_SET(p, BASE_REACHABLE_TIME,
                                              nla_get_msecs(tbp[i]));
@@ -2987,6 +2993,7 @@ static struct neigh_sysctl_table {
                NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(MCAST_PROBES, "mcast_solicit"),
                NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(UCAST_PROBES, "ucast_solicit"),
                NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(APP_PROBES, "app_solicit"),
+               NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(MCAST_REPROBES, "mcast_resolicit"),
                NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(RETRANS_TIME, "retrans_time"),
                NEIGH_SYSCTL_JIFFIES_ENTRY(BASE_REACHABLE_TIME, "base_reachable_time"),
                NEIGH_SYSCTL_JIFFIES_ENTRY(DELAY_PROBE_TIME, "delay_first_probe_time"),