Hi all
We are using net-snmp 5.7.2.1 on Solaris and I have compiled Net-SNMP
with TLS and DTLS Support
# ./configure --with-security-modules=tsm --with-transports=TLSTCP,DTLSUDP
And while testing, I ran the server
snmpd dtlsudp:10161
But when I do a snmpget in the client, got following error.
snmpget -v3 -l authPriv -T
our_identity=13:5D:66:3D:96:05:B2:FB:B8:E7:EA:0D:32:C6:39:5D:07:7A:CA:F9
-T
their_identity=FF:24:CE:70:84:D8:DF:57:3D:AF:2C:A2:2E:04:BE:0B:A1:E8:F2:10
dtlsudp:localhost:10161 sysContact.0
failed to send a DTLS specific packet
tsm: needed to free transport data
failed to send a DTLS specific packet
tsm: needed to free transport data
tsm: needed to free transport data
tsm: needed to free transport data
tsm: needed to free transport data
failed rfc5343 contextEngineID probing
snmpget: Timeout (Error 0)
Then I have root-caused the issue and the reason for this failure is
client will "connect" to the udp socket and then tries to send data by
using sendto or sendmsg.
Sendto and sendmsg are not able to send the data when the udp socket is
in connected mode and the destination address is specified and return
the error EISCONN(A destination address was specified and the socket is
already connected) as per the man page.
Trace of connect-sendmsg
connect(5, 0xFFFF80D8303A8D20, 16, SOV_XPG4_2) = 0
sendmsg(5, 0xFFFF80D8303857F0, 33408) Err#133 EISCONN
Trace of connect-sendto
connect(5, 0xFFFF80D420661790, 16, SOV_XPG4_2) = 0
sendto(5, 0xFFFF80D42064E3B0, 192, 32768, 0x1C63196E0, 16) Err#133 EISCONN
The connect got called in the function
netsnmp_dtlsudp6_transport(net-snmp-5.7.2.1/snmplib/transports/snmpDTLSUDPDomain.c)
1472
1473 if (!local) {
1474 /* dtls needs to bind the socket for SSL_write to work */
1475 if (connect(t->sock, (struct sockaddr *) addr,
sizeof(*addr)) == -1)
1476 snmp_log(LOG_ERR, "dtls: failed to connect\n");
1477 }
1478
And sendmsg or sendto got called in the function
netsnmp_udpbase_send(net-snmp-5.7.2.1/snmplib/transports/snmpUDPBaseDomain.c)
#ifdef netsnmp_udpbase_recvfrom_sendto_defined
340 rc = netsnmp_udp_sendto(t->sock,
341 addr_pair ? &(addr_pair->local_addr.sin.sin_addr)
: NULL,
342 addr_pair ? addr_pair->if_index : 0, to, buf, size);
343#else
344 rc = sendto(t->sock, buf, size, 0, to, sizeof(struct
sockaddr));
345#endif /* netsnmp_udpbase_recvfrom_sendto_defined */
Could you please provide your input on this whether its a bug or not,
and how to fix this issue.
Thank You
Vishwas
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