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net-snmp/agent/mibgroup/ip-mib/data_access/arp_sysctl.c

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/*
* Interface MIB architecture support
*/
#include <net-snmp/net-snmp-config.h>
#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>
#include <net-snmp/data_access/arp.h>
#include <net-snmp/data_access/interface.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/route.h>
#include <netinet/if_ether.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#if !defined(SA_SIZE) && !defined(RT_ROUNDUP)
#define RT_ROUNDUP(a) \
((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
#endif
static int _load_arp_table_from_sysctl(netsnmp_arp_access *);
static int _load_ndp_table_from_sysctl(netsnmp_arp_access *);
netsnmp_arp_access *
netsnmp_access_arp_create(u_int init_flags,
NetsnmpAccessArpUpdate *update_hook,
NetsnmpAccessArpGC *gc_hook,
int *cache_timeout, int *cache_flags,
char *cache_expired)
{
netsnmp_arp_access *access;
access = SNMP_MALLOC_TYPEDEF(netsnmp_arp_access);
if (NULL == access) {
snmp_log(LOG_ERR, "malloc error in netsnmp_access_arp_create\n");
return NULL;
}
access->arch_magic = NULL;
access->magic = NULL;
access->update_hook = update_hook;
access->gc_hook = gc_hook;
access->synchronized = 0;
if (cache_timeout != NULL)
*cache_timeout = 5;
if (cache_flags != NULL)
*cache_flags |= NETSNMP_CACHE_DONT_FREE_BEFORE_LOAD
| NETSNMP_CACHE_AUTO_RELOAD;
access->cache_expired = cache_expired;
return access;
}
int netsnmp_access_arp_delete(netsnmp_arp_access *access)
{
if (NULL == access)
return 0;
netsnmp_access_arp_unload(access);
free(access);
return 0;
}
int netsnmp_access_arp_load(netsnmp_arp_access *access)
{
int err = 0;
access->generation++;
DEBUGMSGTL(("access:route:container",
"route_container_arch_load ipv4\n"));
err = _load_arp_table_from_sysctl(access);
if (err != 0) {
NETSNMP_LOGONCE((LOG_ERR,
"netsnmp_access_arp_ipv4 failed %d\n", err));
goto out;
}
access->gc_hook(access);
access->synchronized = (err == 0);
#ifdef NETSNMP_ENABLE_IPV6
DEBUGMSGTL(("access:route:container",
"route_container_arch_load ipv6\n"));
err = _load_ndp_table_from_sysctl(access);
if (err != 0) {
NETSNMP_LOGONCE((LOG_ERR,
"netsnmp_access_arp_ipv6 failed %d\n", err));
goto out;
}
access->gc_hook(access);
access->synchronized = (err == 0);
#endif
out:
return (err == 0 ? 0 : -1);
}
int netsnmp_access_arp_unload(netsnmp_arp_access *access)
{
access->synchronized = 0;
return 0;
}
static int
_load_arp_table_from_sysctl(netsnmp_arp_access *access)
{
netsnmp_arp_entry *entry;
struct rt_msghdr *rtm;
struct sockaddr_inarp *sin2;
struct sockaddr_dl *sdl;
char *buf, *lim, *newbuf, *next;
int mib[6];
size_t needed;
int err, st;
netsnmp_assert(NULL != access);
mib[0] = CTL_NET;
mib[1] = PF_ROUTE;
mib[2] = 0;
mib[3] = AF_INET;
mib[4] = NET_RT_FLAGS;
#ifdef RTF_LLINFO
mib[5] = RTF_LLINFO;
#elif defined(RTF_LLDATA)
mib[5] = RTF_LLDATA;
#else
mib[5] = 0;
#endif
err = 0;
buf = newbuf = NULL;
/* The following logic was adapted from search(..) in usr.sbin/arp/arp.c */
if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) {
err = errno;
goto out;
}
/* Empty arp table. */
if (needed == 0)
goto out;
for (;;) {
newbuf = realloc(buf, needed);
if (newbuf == NULL) {
err = ENOMEM;
goto out;
}
buf = newbuf;
st = sysctl(mib, 6, buf, &needed, NULL, 0);
if (st == 0 || errno != ENOMEM)
break;
else
needed += needed / 8; /* XXX: why 8? */
}
if (st == -1) {
err = errno;
goto out;
}
lim = buf + needed;
for (next = buf; next < lim; next += rtm->rtm_msglen) {
rtm = (struct rt_msghdr *)next;
sin2 = (struct sockaddr_inarp*)(rtm + 1);
#ifdef SA_SIZE
sdl = (struct sockaddr_dl*)((char *)sin2 + SA_SIZE(sin2));
#else
sdl = (struct sockaddr_dl*)(void *)(RT_ROUNDUP(sin2->sin_len) + (char *)(void *)sin2);
#endif
entry = netsnmp_access_arp_entry_create();
if (NULL == entry) {
err = ENOMEM;
break;
}
entry->generation = access->generation;
entry->if_index = rtm->rtm_index;
entry->arp_ipaddress_len = 4;
memcpy(entry->arp_ipaddress, &sin2->sin_addr.s_addr,
entry->arp_ipaddress_len);
/* HW Address */
entry->arp_physaddress_len = 6;
if (0 < sdl->sdl_alen &&
sdl->sdl_alen <= NETSNMP_ACCESS_ARP_PHYSADDR_BUF_SIZE) {
memcpy(entry->arp_physaddress, LLADDR(sdl), sdl->sdl_alen);
/* Process status */
/* XXX: setting this value for all states is wrong. */
entry->arp_state = INETNETTOMEDIASTATE_REACHABLE;
} else {
entry->arp_physaddress[0] = '\0';
entry->arp_state = INETNETTOMEDIASTATE_INCOMPLETE;
}
/* Process type */
/* XXX: more states should be handled here, probably.. */
if (rtm->rtm_rmx.rmx_expire == 0)
entry->arp_type = INETNETTOMEDIATYPE_STATIC;
else
entry->arp_type = INETNETTOMEDIATYPE_DYNAMIC;
access->update_hook(access, entry);
}
out:
free(buf);
return err;
}
static int
_load_ndp_table_from_sysctl(netsnmp_arp_access *access)
{
#if 1
netsnmp_arp_entry *entry;
struct rt_msghdr *rtm;
struct sockaddr_in6 *sin2;
struct sockaddr_dl *sdl;
size_t needed;
int err, mib[6], st;
char *buf, *lim, *newbuf, *next;
netsnmp_assert(NULL != access);
mib[0] = CTL_NET;
mib[1] = PF_ROUTE;
mib[2] = 0;
mib[3] = AF_INET6;
mib[4] = NET_RT_FLAGS;
#ifdef RTF_LLINFO
mib[5] = RTF_LLINFO;
#elif defined(RTF_LLDATA)
mib[5] = RTF_LLDATA;
#else
mib[5] = 0;
#endif
err = 0;
buf = newbuf = NULL;
if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) {
err = errno;
goto out;
}
/* Empty arp table. */
if (needed == 0)
goto out;
for (;;) {
newbuf = realloc(buf, needed);
if (newbuf == NULL) {
err = ENOMEM;
goto out;
}
buf = newbuf;
st = sysctl(mib, 6, buf, &needed, NULL, 0);
if (st == 0 || errno != ENOMEM)
break;
else
needed += needed / 8; /* XXX: why 8? */
}
if (st == -1) {
err = errno;
goto out;
}
lim = buf + needed;
for (next = buf; next < lim; next += rtm->rtm_msglen) {
rtm = (struct rt_msghdr *)next;
sin2 = (struct sockaddr_in6*)(rtm + 1);
#ifdef SA_SIZE
sdl = (struct sockaddr_dl*)((char *)sin2 + SA_SIZE(sin2));
#else
sdl = (struct sockaddr_dl*)(void *)(RT_ROUNDUP(sin2->sin6_len) + (char *)(void *)sin2);
#endif
if (!(rtm->rtm_flags & RTF_HOST) ||
IN6_IS_ADDR_MULTICAST(&sin2->sin6_addr))
continue;
entry = netsnmp_access_arp_entry_create();
if (NULL == entry) {
err = ENOMEM;
break;
}
entry->generation = access->generation;
entry->if_index = rtm->rtm_index;
entry->arp_ipaddress_len = 16;
memcpy(entry->arp_ipaddress, &sin2->sin6_addr.s6_addr,
entry->arp_ipaddress_len);
/* HW Address */
entry->arp_physaddress_len = sdl->sdl_alen;
if (0 < sdl->sdl_alen &&
sdl->sdl_alen <= NETSNMP_ACCESS_ARP_PHYSADDR_BUF_SIZE) {
memcpy(entry->arp_physaddress, LLADDR(sdl), sdl->sdl_alen);
/* Process status */
/* XXX: setting this value for all states is wrong. */
entry->arp_state = INETNETTOMEDIASTATE_REACHABLE;
} else {
entry->arp_physaddress[0] = '\0';
entry->arp_state = INETNETTOMEDIASTATE_INCOMPLETE;
}
/* Process type */
/* XXX: more states should be handled here, probably.. */
if (rtm->rtm_rmx.rmx_expire == 0)
entry->arp_type = INETNETTOMEDIATYPE_STATIC;
else
entry->arp_type = INETNETTOMEDIATYPE_DYNAMIC;
access->update_hook(access, entry);
}
out:
free(buf);
return err;
#else
return 0;
#endif
}
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