linux arpの内部データ
arpの統計情報が欲しかったのでnetlink経由で取得するものを作った NDTA_PARMSはrtattrが入れ子になっている。
#include <asm/types.h>
#include <sys/socket.h>
#include <linux/netlink.h>
#include <linux/neighbour.h>
#include <linux/rtnetlink.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <stdint.h>
static int seq;
void msg_receive(int sock) {
char buf[4096];
int n = read(sock, buf, sizeof(buf));
if ( n <= 0 ) {
perror("read error\n");
exit(1);
}
struct nlmsghdr *nh = (struct nlmsghdr *)buf;
// printf("read size: %d\n", n);
if ( nh->nlmsg_seq != seq ) {
printf("seq error\n");
exit(1);
}
if ( nh->nlmsg_type == NLMSG_ERROR ) {
printf("error\n");
exit(1);
} else if ( nh->nlmsg_type == RTM_NEWNEIGHTBL ) {
NLMSG_ALIGN(nh->nlmsg_len);
struct ndtmsg *ndtm = NLMSG_DATA(nh);
if ( ndtm->ndtm_family != AF_INET ) {
printf("ndgm_family is not AF_INET\n");
exit(1);
}
struct rtattr *rta;
int len = nh->nlmsg_len - NLMSG_LENGTH(sizeof(struct ndtmsg));
for (rta = (struct rtattr*)((char *)ndtm + sizeof(struct ndtmsg)); RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
switch(rta->rta_type) {
case NDTA_NAME:
printf("NAME: %s\n", (char*)RTA_DATA(rta));
break;
case NDTA_THRESH1:
printf("THRESH1 %d\n", *(uint32_t*)RTA_DATA(rta));
break;
case NDTA_THRESH2:
printf("THRESH2 %d\n", *(uint32_t*)RTA_DATA(rta));
break;
case NDTA_THRESH3:
printf("THRESH3 %d\n", *(uint32_t*)RTA_DATA(rta));
break;
case NDTA_CONFIG:
{
struct ndt_config *config = (struct ndt_config*)RTA_DATA(rta);
printf("CONFIG:\n");
printf("\tkey_len: %d\n", config->ndtc_key_len);
printf("\tentry_size: %d\n", config->ndtc_entry_size);
printf("\tentries: %d\n", config->ndtc_entries);
printf("\tlast_flush: %d\n", config->ndtc_last_flush);
printf("\tlast_rand: %d\n", config->ndtc_last_rand);
printf("\thash_rnd: %d\n", config->ndtc_hash_rnd);
printf("\thash_mask: %d\n", config->ndtc_hash_mask);
printf("\thash_chain_gc: %d\n", config->ndtc_hash_chain_gc);
printf("\tproxy_qlen: %d\n", config->ndtc_proxy_qlen);
}
break;
case NDTA_PARMS:
{
printf("PARAMS:\n");
struct rtattr *parm_rta;
int parm_len = rta->rta_len;
for (parm_rta = rta + 1; RTA_OK(parm_rta, parm_len); parm_rta = RTA_NEXT(parm_rta, parm_len)) {
switch(parm_rta->rta_type) {
case NDTPA_IFINDEX:
printf("\tifindex: %d\n", *(uint32_t*)RTA_DATA(parm_rta));
break;
case NDTPA_REFCNT:
printf("\trefcnt: %d\n", *(uint32_t*)RTA_DATA(parm_rta));
break;
case NDTPA_REACHABLE_TIME:
printf("\treachable_time: %lld\n", *(uint64_t*)RTA_DATA(parm_rta));
break;
case NDTPA_BASE_REACHABLE_TIME:
printf("\tbase_reachable_time: %lld\n", *(uint64_t*)RTA_DATA(parm_rta));
break;
case NDTPA_RETRANS_TIME:
printf("\tretrans_time: %lld\n", *(uint64_t*)RTA_DATA(parm_rta));
break;
case NDTPA_GC_STALETIME:
printf("\tgc_staletime: %lld\n", *(uint64_t*)RTA_DATA(parm_rta));
break;
case NDTPA_DELAY_PROBE_TIME:
printf("\tdelay_probe_time: %lld\n", *(uint64_t*)RTA_DATA(parm_rta));
break;
case NDTPA_QUEUE_LEN:
printf("\tqueue_len: %d\n", *(uint32_t*)RTA_DATA(parm_rta));
break;
case NDTPA_APP_PROBES:
printf("\tapp_probes: %d\n", *(uint32_t*)RTA_DATA(parm_rta));
break;
case NDTPA_UCAST_PROBES:
printf("\tucast_probes: %d\n", *(uint32_t*)RTA_DATA(parm_rta));
break;
case NDTPA_MCAST_PROBES:
printf("\tmcast_probes: %d\n", *(uint32_t*)RTA_DATA(parm_rta));
break;
case NDTPA_ANYCAST_DELAY:
printf("\tanycast_delay: %lld\n", *(uint64_t*)RTA_DATA(parm_rta));
break;
case NDTPA_PROXY_DELAY:
printf("\tproxy_delay: %d\n", *(uint64_t*)RTA_DATA(parm_rta));
break;
case NDTPA_PROXY_QLEN:
printf("\tproxy_qlen: %d\n", *(uint32_t*)RTA_DATA(parm_rta));
break;
case NDTPA_LOCKTIME:
printf("\tlocktime: %d\n", *(uint64_t*)RTA_DATA(parm_rta));
break;
}
}
}
break;
case NDTA_STATS:
{
struct ndt_stats *stats = (struct ndt_stats*)RTA_DATA(rta);
printf("STATS:\n");
printf("\tallocs: %d\n", stats->ndts_allocs);
printf("\tdestorys: %d\n", stats->ndts_destroys);
printf("\tgrow: %d\n", stats->ndts_hash_grows);
printf("\tres_failed: %d\n", stats->ndts_res_failed);
printf("\tlookups %d\n", stats->ndts_lookups);
printf("\thits: %d\n", stats->ndts_hits);
printf("\trcv_probes_mcast: %d\n", stats->ndts_rcv_probes_mcast);
printf("\trcv_probes_ucast: %d\n", stats->ndts_rcv_probes_ucast);
printf("\tperiodic_gc_runs: %d\n", stats->ndts_periodic_gc_runs);
printf("\tforced_gc_runs: %d\n", stats->ndts_forced_gc_runs);
}
break;
case NDTA_GC_INTERVAL:
printf("GC_INTERVAL %lld\n", *(uint64_t*)RTA_DATA(rta));
break;
}
}
}
}
void main() {
srand(time(NULL));
seq = rand();
int sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
if ( sock == -1 ) {
perror("sock error\n");
exit(1);
}
struct {
struct nlmsghdr nh;
struct rtgenmsg rt;
} h;
struct sockaddr_nl nl;
memset(&nl, 0, sizeof(nl));
nl.nl_family = AF_NETLINK;
if ( bind(sock, (struct sockaddr*)&nl, sizeof(nl)) == -1 ) {
perror("bind error\n");
exit(1);
}
memset(&h, 0, sizeof(h));
h.nh.nlmsg_type = RTM_GETNEIGHTBL;
h.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP;
h.nh.nlmsg_len = NLMSG_LENGTH(sizeof(h.rt));
h.nh.nlmsg_seq = seq;
h.rt.rtgen_family = AF_INET;
int n = write(sock, &h, sizeof(h));
if ( n <= 0 ) {
perror("write error\n");
exit(1);
}
msg_receive(sock);
}
出力はこんな感じ
NAME: arp_cache
GC_INTERVAL 10000
THRESH1 128
THRESH2 512
THRESH3 1024
CONFIG:
key_len: 4
entry_size: 260
entries: 3
last_flush: 27997298
last_rand: 63783
hash_rnd: 398501669
hash_mask: 7
hash_chain_gc: 0
proxy_qlen: 0
STATS:
allocs: 49
destorys: 46
grow: 0
res_failed: 25
lookups 61661
hits: 48360
rcv_probes_mcast: 0
rcv_probes_ucast: 0
periodic_gc_runs: 2274
forced_gc_runs: 0
PARAMS:
refcnt: 1
queue_len: 3
proxy_qlen: 64
app_probes: 0
ucast_probes: 3
mcast_probes: 3
reachable_time: 18336
base_reachable_time: 20000
gc_staletime: 60000
delay_probe_time: 5000
retrans_time: 1000
anycast_delay: 1000
proxy_delay: 800
locktime: 1000
