CODEWITHSUNDEEP
cnetwork-programmingsnmpnet-snmp
mython paster
mython paster

Reputation: 41

Trouble setting value with net-snmp C API

Here is the relevant code:

pdu = snmp_pdu_create(SNMP_MSG_SET);

if (snmp_add_var(pdu, oid, oid_len, ASN_INTEGER, "1" ) != 0 )
    snmp_perror("failed");

I get an error "Bad value type: weird Unicode character "

When I run this snmpset command in terminal:

snmpset -v 3 -u <user> <ip> <oid> integer 1

it works fine, so why isn't it working in my C program?

Upvotes: 0

Views: 818

Answers (1)

Lightness Races in Orbit
Lightness Races in Orbit

Reputation: 385295

You're using snmp_add_var wrong. It's the equivalent of snmpset in a sense, so you should be passing the character 'i' instead of the constant ASN_INTEGER, which is designed for something else.

ASN_INTEGER is defined to be ((u_char)0x02), so it's the parsing of that argument that's causing decoding difficulties.

The "something else" is the function you probably want to be using instead, which is snmp_pdu_add_variable:

pdu = snmp_pdu_create(SNMP_MSG_SET);

uint32_t val = 1;
if (snmp_pdu_add_variable(pdu, oid, oid_len, ASN_INTEGER, &val, sizeof(val)) == nullptr)
    snmp_perror("failed");

Note how it is "typed", rather than taking a string to lexically convert.

Upvotes: 0

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