[TE7] IPv6 Only case resolve failing with chip-tool

[praveenCY]

Problem

Commissioning is failing for IPv6 only case with CASESession Timeout

Update below flag to disable ipv4 for resolve
chip_inet_config_enable_ipv4=false

CHIP:IN: Sending plaintext msg 0xaaaaf5414fa0 with MessageCounter:3028697144 to 0x0000000000000000 at monotonic time: 344622313 msec
CHIP:EM: Retransmitted MessageCounter:3028697144 on exchange 29121i Send Cnt 1
CHIP:IN: Sending plaintext msg 0xaaaaf5414fa0 with MessageCounter:3028697144 to 0x0000000000000000 at monotonic time: 344622568 msec
CHIP:EM: Retransmitted MessageCounter:3028697144 on exchange 29121i Send Cnt 2
CHIP:IN: Sending plaintext msg 0xaaaaf5414fa0 with MessageCounter:3028697144 to 0x0000000000000000 at monotonic time: 344622825 msec
CHIP:EM: Retransmitted MessageCounter:3028697144 on exchange 29121i Send Cnt 3
CHIP:EM: Failed to Send CHIP MessageCounter:3028697144 on exchange 29121i sendCount: 3 max retries: 3
CHIP:SC: CASESession timed out while waiting for a response from the peer. Current state was 1
CHIP:CTL: Device connection failed. Error ../../third_party/connectedhomeip/src/protocols/secure_channel/CASESession.cpp:291: CHIP Error 0x00000032: Timeout
CHIP:TOO: Device commissioning Failure: ../../third_party/connectedhomeip/src/protocols/secure_channel/CASESession.cpp:291: CHIP Error 0x00000032: Timeout
CHIP:-: ../../third_party/connectedhomeip/src/protocols/secure_channel/CASESession.cpp:291: CHIP Error 0x00000032: Timeout at ../../commands/common/CHIPCommand.cpp:84
CHIP:TOO: Run command failure: ../../third_party/connectedhomeip/src/protocols/secure_channel/CASESession.cpp:291: CHIP Error 0x00000032: Timeout

Reason
Resolve gets IPV6 link address instead of Global address (resolve works if Global address is resolved)

Ping to Link address works
ubuntu@matter-te-7:~/cli$ ping fe80::d64d:a4ff:fea0:2a4%2
PING fe80::d64d:a4ff:fea0:2a4%2(fe80::d64d:a4ff:fea0:2a4%eth0) 56 data bytes
64 bytes from fe80::d64d:a4ff:fea0:2a4%eth0: icmp_seq=1 ttl=255 time=253 ms
64 bytes from fe80::d64d:a4ff:fea0:2a4%eth0: icmp_seq=2 ttl=255 time=179 ms

Resolve

• Working case
  CHIP:DIS: Node ID resolved for 0x0000000000BC5C01 to [2001:db6:1:0:d64d:a4ff:fea0:2a4]:5540

• Failure case
  CHIP:DIS: Node ID resolved for 0x00000000029365F1 to [fe80::d64d:a4ff:fea0:2a4]:5540

Logs

• Failure case
  LOCK-TC-IPV6-Rpi4.txt
  LOCK-TC-IPV6-P6.txt

• Working case
  LOCK-TC-IPV6-working.txt
  LOCK-TC-IPV6-working-P6.txt

[praveenCY]

Wireshark Capture shows UDP packet from Controller and Device not sending anything back

acket is dropped in below code

nd6_send_ns

for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
  if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
        ip6_addr_netcmp_zone(target_addr, netif_ip6_addr(netif, i))) {
    src_addr = netif_ip6_addr(netif, i);
    break;
  }
}

if (i == LWIP_IPV6_NUM_ADDRESSES) {
  LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_WARNING, ("ICMPv6 NS: no available src address\n"));
  ND6_STATS_INC(nd6.err);
  return;
}

[praveenCY]

Issue is root caused to zone configuration in ip6_addr for latest lwip branch (this variable is not present in third_party/lwip : this is old lwip tag)
struct ip6_addr {
u32_t addr[4];
#if LWIP_IPV6_SCOPES
u8_t zone;
#endif /* LWIP_IPV6_SCOPES */
};

logs:
fe80:0:0:0:e65f:1ff:fe2f:c4b3 target_address.zone 60 ==> zone is configured as 60 but neighor_cache for the same LL address is 1 and ip6_addr_cmp fails in nd6_find_neighbor_cache_entry

fe80:0:0:0:290:4cff:fe0f:f260 neighbor_cache[i].next_hop_address.zone 1
fe80:0:0:0:e65f:1ff:fe2f:c4b3 neighbor_cache[i].next_hop_address.zone 1 (edited)

[praveenCY]

Fix for this issue
--- a/src/inet/IPAddress.cpp
+++ b/src/inet/IPAddress.cpp
@@ -179,6 +179,7 @@ ip6_addr_t IPAddress::ToIPv6() const
{
ip6_addr_t ipAddr;
static_assert(sizeof(ipAddr.addr) == sizeof(Addr), "ip6_addr_t size mismatch");
+ memset(&ipAddr, 0x0, sizeof(ipAddr));
memcpy(&ipAddr.addr, Addr, sizeof(ipAddr.addr));
return ipAddr;
}