Commit 6f74f4a6 authored by Vojtech Vilimek's avatar Vojtech Vilimek
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moving shared parts to snmp_utils

parent ad9833e4
Pipeline #106877 failed with stages
in 4 minutes and 36 seconds
/*
* BIRD -- Simple Network Management Protocol (SNMP) helper functions
*
* (c) 2022 Vojtech Vilimek <vojtech.vilimek@nic.cz>
* (c) 2022 CZ.NIC z.s.p.o
*
* Can be freely distributed and used under the terms of the GNU GPL.
*
*/
#include "snmp_utils.h"
/**
* snmp_is_oid_empty - check if oid is null-valued
* @oid: object identifier to check
*
* Test if the oid header is full of zeroes. For @oid NULL returns 0.
*/
int
snmp_is_oid_empty(struct oid *oid)
{
if (oid != NULL)
return oid->n_subid == 0 && oid->prefix == 0 && oid->include == 0;
else
return 0;
}
/**
* snmp_pkt_len - returns size of SNMP packet payload (without header)
* @buf: packet first byte
* @pkt: first byte past packet end
*/
size_t
snmp_pkt_len(byte *buf, byte *pkt)
{
return (pkt - buf) - AGENTX_HEADER_SIZE;
}
/**
* snmp_str_size - return in packet size of supplied string
* @str: measured string
*
* Returned value is string length aligned to 4 byte with 32bit length
* annotation included.
*/
size_t
snmp_str_size(const char *str)
{
return 4 + BIRD_ALIGN(strlen(str), 4);
}
/**
* snmp_oid_size - measure size of oid in bytes
* @o: object identifier to use
*/
uint
snmp_oid_size(struct oid *o)
{
//return 4 + o->n_subid * 4;
return 4 + (o->n_subid << 2);
}
/**
* snmp_vb_size - measure size of varbind in bytes
* @vb: variable binding to use
*/
uint
snmp_varbind_size(struct agentx_varbind *vb)
{
return snmp_oid_size(&vb->name) + 4;
}
struct agentx_varbind *
snmp_create_varbind(byte *buf, struct oid *oid)
{
struct agentx_varbind *vb = (void*) buf;
memcpy(&vb->name, oid, snmp_oid_size(oid));
return vb;
}
byte *snmp_fix_varbind(struct agentx_varbind *vb, struct oid *new)
{
memcpy(&vb->name, new, snmp_oid_size(new));
return (void *) vb + snmp_varbind_size(vb);
}
/**
* snmp_oid_ip4_index - check IPv4 address validity in oid
* @o: object identifier holding ip address
* @start: index of first address id
*/
int
snmp_valid_ip4_index(struct oid *o, uint start)
{
if (start + 3 < o->n_subid)
return snmp_valid_ip4_index_unsafe(o, start);
else
return 0; // false
}
/**
* snmp_valid_ip4_index_unsafe - check validity of IPv4 address in oid
* @o: object identifier holding ip address
* @start: index of first address id
*
* This function is unsafe - no checks of object identifier ids
* length sufficiency is done.
*/
int
snmp_valid_ip4_index_unsafe(struct oid *o, uint start)
{
for (int i = 0; i < 4; i++)
if (o->ids[start + i] >= 256)
return 0; // false
return 1; // true
}
/**
* snmp_put_str - put string into SNMP PDU transcieve buffer
* @buf: pointer to first unoccupied buffer byte
* @str: string to place
*
* Handles all conditions specified by RFC, namely string length annotation
* and padding 4 byte alignment with zeroes. Return NULL if string is too large
* for SNMP message.
*/
byte *
snmp_put_str(byte *buf, const char *str)
{
uint len = strlen(str);
uint slen = BIRD_ALIGN(len, 4);
if (len > MAX_STR)
return NULL;
STORE_PTR(buf, len);
memcpy(buf + 4, str, len);
for (uint i = 0; i < slen - len; i++)
buf[len + i] = 0x00; // PADDING
return buf + snmp_str_size(str);
}
byte *
snmp_put_blank(byte *buf)
{
STORE_PTR(buf, 0);
return buf + 4;
}
/**
* snmp_put_oid - put oid into SNMP PDU transcieve buffer
* @buf: pointer to first free buffer byte
* @oid: object identifier to use
*/
byte *
snmp_put_oid(byte *buf, struct oid *oid)
{
put_u8(buf, oid->n_subid);
put_u8(++buf, oid->prefix);
put_u8(++buf, oid->include);
put_u8(++buf, 0); // PADDING
/* last increment */
++buf;
/* copy OID data */
#ifdef SNMP_NATIVE
for (uint i = 0; i < oid->n_subid; i++)
*(((u32 *) buf) + i) = oid->ids[i];
#else
put_u32s(buf, oid->ids, oid->n_subid << 2);
#endif
return buf + (oid->n_subid << 2);
}
/**
* snmp_put_fbyte - put one padded byte to SNMP PDU transcieve buffer
* @buf: pointer to free buffer byte
* @data: byte to use
*
* Put @data into buffer @buf with 3B zeroed padding.
*/
/* paste data at first byte in message
* with 3B of padding
*/
byte *
snmp_put_fbyte(byte *buf, u8 data)
{
log(L_INFO "paste_fbyte()");
put_u8(buf, data);
put_u24(++buf, 0); // PADDING
return buf + 3;
}
void
snmp_oid_ip4_index(struct oid *o, uint start, ip4_addr addr)
{
u32 temp = ip4_to_u32(addr);
STORE(o->ids[start], temp >> 24);
STORE(o->ids[start + 1], (temp >> 16) & 0xFF);
STORE(o->ids[start + 2], (temp >> 8) & 0xFF);
STORE(o->ids[start + 3], temp & 0xFF);
}
void snmp_oid_dump(struct oid *oid)
{
log(L_WARN "OID DUMP ========");
if (oid == NULL)
{
log(L_WARN "is eqaul to NULL");
log(L_WARN "OID DUMP END ====");
log(L_WARN);
return;
}
else if (snmp_is_oid_empty(oid))
{
log(L_WARN "is empty");
log(L_WARN "OID DUMP END ====");
log(L_WARN);
return;
}
log(L_WARN " #ids: %4u prefix %3u include: %5s",
oid->n_subid, oid->prefix, (oid->include)? "true" : "false");
log(L_WARN "IDS -------------");
for (int i = 0; i < oid->n_subid; i++)
log(L_WARN " %2u: %11u ~ 0x%08X", i, oid->ids[i], oid->ids[i]);
log(L_WARN "OID DUMP END ====");
log(L_WARN);
}
#ifndef _BIRD_SNMP_UTILS_H_
#define _BIRD_SNMP_UTILS_H_
#include "subagent.h"
size_t snmp_pkt_len(byte *buf, byte *pkt);
size_t snmp_str_size(const char *str);
int snmp_is_oid_empty(struct oid *oid);
int snmp_valid_ip4_index(struct oid *o, uint start);
int snmp_valid_ip4_index_unsafe(struct oid *o, uint start);
uint snmp_oid_size(struct oid *o);
uint snmp_varbind_size(struct agentx_varbind *vb);
struct agentx_varbind *snmp_create_varbind(byte* buf, struct oid *oid);
byte *snmp_fix_varbind(struct agentx_varbind *vb, struct oid *new);
int snmp_oid_compare(struct oid *first, struct oid *second);
byte *snmp_no_such_object(byte *buf, struct agentx_varbind *vb, struct oid *oid);
byte *snmp_no_such_instance(byte *buf, struct agentx_varbind *vb, struct oid *oid);
byte *snmp_put_str(byte *buf, const char *str);
byte *snmp_put_blank(byte *buf);
byte *snmp_put_oid(byte *buf, struct oid *oid);
byte *snmp_put_fbyte(byte *buf, u8 data);
void snmp_oid_ip4_index(struct oid *o, uint start, ip4_addr addr);
void snmp_oid_dump(struct oid *oid);
#endif
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