/****************************************************************************
* Module for ucd-snmpd reading IP Firewall accounting rules. *
* It reads "/proc/net/ip_acct". If the file has a wrong format it silently *
* returns erroneous data but doesn't do anything harmfull. Based (on the *
* output of) mib2c, wombat.c, proc.c and the Linux kernel. *
* Author: Cristian.Estan@net.utcluj.ro *
***************************************************************************/
#include <net-snmp/net-snmp-config.h>
#if TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# if HAVE_SYS_TIME_H
# include <sys/time.h>
# else
# include <time.h>
# endif
#endif
#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>
#include "util_funcs/header_simple_table.h"
#include "ipfwacc.h"
/*
* According to the 2.0.33 Linux kernel, assuming we use ipv4 any line from
* * "/proc/net/ip_acct should fit into
* * 8+1+8+2+8+1+8+1+16+1+8+1+4+1+2+1+2+1+20+20+10*(1+5)+2+2+2+2=182
* * characters+ newline.
*/
#define IPFWRULELEN 200
#define IP_FW_F_ALL 0x0000 /* This is a universal packet firewall */
#define IP_FW_F_TCP 0x0001 /* This is a TCP packet firewall */
#define IP_FW_F_UDP 0x0002 /* This is a UDP packet firewall */
#define IP_FW_F_ICMP 0x0003 /* This is a ICMP packet firewall */
#define IP_FW_F_KIND 0x0003 /* Mask to isolate firewall kind */
#define IP_FW_F_SRNG 0x0008 /* The first two src ports are a min *
* and max range (stored in host byte *
* order). */
#define IP_FW_F_DRNG 0x0010 /* The first two dst ports are a min *
* and max range (stored in host byte *
* order). *
* (ports[0] <= port <= ports[1]) */
#define IP_FW_F_BIDIR 0x0040 /* For bidirectional firewalls */
#define IP_FW_F_ACCTIN 0x1000 /* Account incoming packets only. */
#define IP_FW_F_ACCTOUT 0x2000 /* Account outgoing packets only. */
static unsigned char rule[IPFWRULELEN]; /*Buffer for reading a line from
* /proc/net/ip_acct. Care has been taken
* not to read beyond the end of this
* buffer, even if rules are in an
* unexpected format
*/
/*
* This function reads the rule with the given number into the buffer. It
* * returns the number of rule read or 0 if the number is invalid or other
* * problems occur. If the argument is 0 it returns the number of accounting
* * rules. No caching of rules is done.
*/
static int
readrule(unsigned int number)
{
int i;
FILE *f = fopen("/proc/net/ip_acct", "rt");
if (!f)
return 0;
/*
* get rid of "IP accounting rules" line
*/
if (!fgets((char *) rule, sizeof(rule), f)) {
fclose(f);
return 0;
}
for (i = 1; i != number; i++)
if (!fgets((char *) rule, sizeof(rule), f)) {
fclose(f);
return (number ? 0 : (i - 1));
}
if (!fgets((char *) rule, sizeof(rule), f)) {
fclose(f);
return 0;
}
fclose(f);
return i;
}
static unsigned long ret_val; /* Used by var_ipfwacc to return ulongs */
/*
* This function converts the hexadecimal representation of an IP address from
* * the rule buffer to an unsigned long. The result is stored in the ret_val
* * variable. The parameter indicates the position where the address starts. It
* * only works with uppercase letters and assumes input is correct. Had to use
* * this because stol returns a signed long.
*/
NETSNMP_STATIC_INLINE void
atoip(int pos)
{
int i;
ret_val = 0;
for (i = 0; i < 32; i += 8) {
unsigned long value = (((rule[pos]) >= '0' && rule[pos] <= '9') ?
rule[pos] - '0' : rule[pos] - 'A' + 10);
pos++;
value = (value << 4) + (((rule[pos]) >= '0' && rule[pos] <= '9') ?
rule[pos] - '0' : rule[pos] - 'A' + 10);
pos++;
ret_val |= (value << i);
}
}
/*
* This function parses the flags field from the line in the buffer
*/
static unsigned long int
getflags(void)
{
unsigned long int flags;
int i = 37; /* position in the rule */
/*
* skipping via name
*/
while (rule[i] != ' ' && i < IPFWRULELEN - 12)
i++;
/*
* skipping via address
*/
i += 10;
for (flags = 0; rule[i] != ' ' && i < IPFWRULELEN - 1; i++) {
int value = (((rule[i]) >= '0' && rule[i] <= '9') ?
rule[i] - '0' : rule[i] - 'A' + 10);
flags = (flags << 4) + value;
}
return flags;
}
/*
* This function reads into ret_val a field from the rule buffer. The field
* * is a base 10 long integer and the parameter skip tells us how many fields
* * to skip after the "via addrress" field (including the flag field)
*/
static void
getnumeric(int skip)
{
int i = 37; /* position in the rule */
/*
* skipping via name
*/
while (rule[i] != ' ' && i < IPFWRULELEN - 12)
i++;
/*
* skipping via address
*/
i += 10;
while (skip > 0) {
skip--;
/*
* skipping field, than subsequent spaces
*/
while (rule[i] != ' ' && i < IPFWRULELEN - 2)
i++;
while (rule[i] == ' ' && i < IPFWRULELEN - 1)
i++;
}
for (ret_val = 0; rule[i] != ' ' && i < IPFWRULELEN - 1; i++)
ret_val = ret_val * 10 + rule[i] - '0';
}
/*
* this variable defines function callbacks and type return information
* for the ipfwaccounting mib
*/
struct variable2 ipfwacc_variables[] = {
{IPFWACCINDEX, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCINDEX}},
{IPFWACCSRCADDR, ASN_IPADDRESS, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCSRCADDR}},
{IPFWACCSRCNM, ASN_IPADDRESS, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCSRCNM}},
{IPFWACCDSTADDR, ASN_IPADDRESS, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCDSTADDR}},
{IPFWACCDSTNM, ASN_IPADDRESS, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCDSTNM}},
{IPFWACCVIANAME, ASN_OCTET_STR, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCVIANAME}},
{IPFWACCVIAADDR, ASN_IPADDRESS, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCVIAADDR}},
{IPFWACCPROTO, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCPROTO}},
{IPFWACCBIDIR, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCBIDIR}},
{IPFWACCDIR, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCDIR}},
{IPFWACCBYTES, ASN_COUNTER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCBYTES}},
{IPFWACCPACKETS, ASN_COUNTER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCPACKETS}},
{IPFWACCNSRCPRTS, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCNSRCPRTS}},
{IPFWACCNDSTPRTS, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCNDSTPRTS}},
{IPFWACCSRCISRNG, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCSRCISRNG}},
{IPFWACCDSTISRNG, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCDSTISRNG}},
{IPFWACCPORT1, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCPORT1}},
{IPFWACCPORT2, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCPORT2}},
{IPFWACCPORT3, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCPORT3}},
{IPFWACCPORT4, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCPORT4}},
{IPFWACCPORT5, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCPORT5}},
{IPFWACCPORT6, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCPORT6}},
{IPFWACCPORT7, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCPORT7}},
{IPFWACCPORT8, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCPORT8}},
{IPFWACCPORT9, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCPORT9}},
{IPFWACCPORT10, ASN_INTEGER, NETSNMP_OLDAPI_RONLY,
var_ipfwacc, 1, {IPFWACCPORT10}}
};
oid ipfwacc_variables_oid[] =
{ 1, 3, 6, 1, 4, 1, 2021, 13, 1, 1, 1 };
void
init_ipfwacc(void)
{
REGISTER_MIB("misc/ipfwacc", ipfwacc_variables, variable2,
ipfwacc_variables_oid);
}
u_char *
var_ipfwacc(struct variable *vp,
oid * name,
size_t * length,
int exact, size_t * var_len, WriteMethod ** write_method)
{
*write_method = NULL; /* assume it isnt writable for the time being */
*var_len = sizeof(ret_val); /* assume an integer and change later if not */
if (header_simple_table
(vp, name, length, exact, var_len, write_method, readrule(0)))
return (NULL);
if (readrule(name[*length - 1])) {
/*
* this is where we do the value assignments for the mib results.
*/
switch (vp->magic) {
case IPFWACCINDEX:
ret_val = name[*length - 1];
return ((u_char *) (&ret_val));
case IPFWACCSRCADDR:
atoip(0);
return ((u_char *) (&ret_val));
case IPFWACCSRCNM:
atoip(9);
return ((u_char *) (&ret_val));
case IPFWACCDSTADDR:
atoip(19);
return ((u_char *) (&ret_val));
case IPFWACCDSTNM:
atoip(28);
return ((u_char *) (&ret_val));
case IPFWACCVIANAME:
{
int i = 37; /* position in the rule */
while (rule[i] != ' ' && i < IPFWRULELEN - 1)
i++;
rule[i] = 0;
return (rule + 37);
}
case IPFWACCVIAADDR:
{
int i = 37; /* position in the rule */
while (rule[i] != ' ' && i < IPFWRULELEN - 9)
i++;
atoip(i + 1);
return ((u_char *) (&ret_val));
}
case IPFWACCPROTO:
switch (getflags() & IP_FW_F_KIND) {
case IP_FW_F_ALL:
ret_val = 2;
return ((u_char *) (&ret_val));
case IP_FW_F_TCP:
ret_val = 3;
return ((u_char *) (&ret_val));
case IP_FW_F_UDP:
ret_val = 4;
return ((u_char *) (&ret_val));
case IP_FW_F_ICMP:
ret_val = 5;
return ((u_char *) (&ret_val));
default:
ret_val = 1;
return ((u_char *) (&ret_val));
}
case IPFWACCBIDIR:
ret_val = ((getflags() & IP_FW_F_BIDIR) ? 2 : 1);
return ((u_char *) (&ret_val));
case IPFWACCDIR:
ret_val = (getflags() & (IP_FW_F_ACCTIN | IP_FW_F_ACCTOUT));
if (ret_val == IP_FW_F_ACCTIN)
ret_val = 2;
else if (ret_val == IP_FW_F_ACCTOUT)
ret_val = 3;
else
ret_val = 1;
return ((u_char *) (&ret_val));
case IPFWACCBYTES:
getnumeric(4);
return ((u_char *) (&ret_val));
case IPFWACCPACKETS:
getnumeric(3);
return ((u_char *) (&ret_val));
case IPFWACCNSRCPRTS:
getnumeric(1);
return ((u_char *) (&ret_val));
case IPFWACCNDSTPRTS:
getnumeric(2);
return ((u_char *) (&ret_val));
case IPFWACCSRCISRNG:
ret_val = ((getflags() & IP_FW_F_SRNG) ? 1 : 2);
return ((u_char *) (&ret_val));
case IPFWACCDSTISRNG:
ret_val = ((getflags() & IP_FW_F_DRNG) ? 1 : 2);
return ((u_char *) (&ret_val));
case IPFWACCPORT1:
case IPFWACCPORT2:
case IPFWACCPORT3:
case IPFWACCPORT4:
case IPFWACCPORT5:
case IPFWACCPORT6:
case IPFWACCPORT7:
case IPFWACCPORT8:
case IPFWACCPORT9:
case IPFWACCPORT10:
getnumeric(5 + (vp->magic) - IPFWACCPORT1);
return ((u_char *) (&ret_val));
}
}
return NULL;
}