/contrib/ntp/ntpd/ntp_monitor.c
https://bitbucket.org/freebsd/freebsd-head/ · C · 358 lines · 218 code · 38 blank · 102 comment · 41 complexity · 0df9be83c4b2c1b855ef6aa0a2b1cf3a MD5 · raw file
- /*
- * ntp_monitor - monitor ntpd statistics
- */
- #ifdef HAVE_CONFIG_H
- # include <config.h>
- #endif
- #include "ntpd.h"
- #include "ntp_io.h"
- #include "ntp_if.h"
- #include "ntp_stdlib.h"
- #include <ntp_random.h>
- #include <stdio.h>
- #include <signal.h>
- #ifdef HAVE_SYS_IOCTL_H
- # include <sys/ioctl.h>
- #endif
- /*
- * I'm still not sure I like what I've done here. It certainly consumes
- * memory like it is going out of style, and also may not be as low
- * overhead as I'd imagined.
- *
- * Anyway, we record statistics based on source address, mode and
- * version (for now, anyway. Check the code). The receive procedure
- * calls us with the incoming rbufp before it does anything else.
- *
- * Each entry is doubly linked into two lists, a hash table and a
- * most-recently-used list. When a packet arrives it is looked up in
- * the hash table. If found, the statistics are updated and the entry
- * relinked at the head of the MRU list. If not found, a new entry is
- * allocated, initialized and linked into both the hash table and at the
- * head of the MRU list.
- *
- * Memory is usually allocated by grabbing a big chunk of new memory and
- * cutting it up into littler pieces. The exception to this when we hit
- * the memory limit. Then we free memory by grabbing entries off the
- * tail for the MRU list, unlinking from the hash table, and
- * reinitializing.
- *
- * trimmed back memory consumption ... jdg 8/94
- */
- /*
- * Limits on the number of structures allocated. This limit is picked
- * with the illicit knowlege that we can only return somewhat less
- * than 8K bytes in a mode 7 response packet, and that each structure
- * will require about 20 bytes of space in the response.
- *
- * ... I don't believe the above is true anymore ... jdg
- */
- #ifndef MAXMONMEM
- #define MAXMONMEM 600 /* we allocate up to 600 structures */
- #endif
- #ifndef MONMEMINC
- #define MONMEMINC 40 /* allocate them 40 at a time */
- #endif
- /*
- * Hashing stuff
- */
- #define MON_HASH_SIZE 128
- #define MON_HASH_MASK (MON_HASH_SIZE-1)
- #define MON_HASH(addr) sock_hash(addr)
- /*
- * Pointers to the hash table, the MRU list and the count table. Memory
- * for the hash and count tables is only allocated if monitoring is
- * turned on.
- */
- static struct mon_data *mon_hash[MON_HASH_SIZE]; /* list ptrs */
- struct mon_data mon_mru_list;
- /*
- * List of free structures structures, and counters of free and total
- * structures. The free structures are linked with the hash_next field.
- */
- static struct mon_data *mon_free; /* free list or null if none */
- static int mon_total_mem; /* total structures allocated */
- static int mon_mem_increments; /* times called malloc() */
- /*
- * Initialization state. We may be monitoring, we may not. If
- * we aren't, we may not even have allocated any memory yet.
- */
- int mon_enabled; /* enable switch */
- u_long mon_age = 3000; /* preemption limit */
- static int mon_have_memory;
- static void mon_getmoremem P((void));
- static void remove_from_hash P((struct mon_data *));
- /*
- * init_mon - initialize monitoring global data
- */
- void
- init_mon(void)
- {
- /*
- * Don't do much of anything here. We don't allocate memory
- * until someone explicitly starts us.
- */
- mon_enabled = MON_OFF;
- mon_have_memory = 0;
- mon_total_mem = 0;
- mon_mem_increments = 0;
- mon_free = NULL;
- memset(&mon_hash[0], 0, sizeof mon_hash);
- memset(&mon_mru_list, 0, sizeof mon_mru_list);
- }
- /*
- * mon_start - start up the monitoring software
- */
- void
- mon_start(
- int mode
- )
- {
- if (mon_enabled != MON_OFF) {
- mon_enabled |= mode;
- return;
- }
- if (mode == MON_OFF)
- return;
-
- if (!mon_have_memory) {
- mon_total_mem = 0;
- mon_mem_increments = 0;
- mon_free = NULL;
- mon_getmoremem();
- mon_have_memory = 1;
- }
- mon_mru_list.mru_next = &mon_mru_list;
- mon_mru_list.mru_prev = &mon_mru_list;
- mon_enabled = mode;
- }
- /*
- * mon_stop - stop the monitoring software
- */
- void
- mon_stop(
- int mode
- )
- {
- register struct mon_data *md, *md_next;
- register int i;
- if (mon_enabled == MON_OFF)
- return;
- if ((mon_enabled & mode) == 0 || mode == MON_OFF)
- return;
- mon_enabled &= ~mode;
- if (mon_enabled != MON_OFF)
- return;
-
- /*
- * Put everything back on the free list
- */
- for (i = 0; i < MON_HASH_SIZE; i++) {
- md = mon_hash[i]; /* get next list */
- mon_hash[i] = NULL; /* zero the list head */
- while (md != NULL) {
- md_next = md->hash_next;
- md->hash_next = mon_free;
- mon_free = md;
- md = md_next;
- }
- }
- mon_mru_list.mru_next = &mon_mru_list;
- mon_mru_list.mru_prev = &mon_mru_list;
- }
- void
- ntp_monclearinterface(struct interface *interface)
- {
- struct mon_data *md;
- for (md = mon_mru_list.mru_next; md != &mon_mru_list;
- md = md->mru_next) {
- if (md->interface == interface)
- {
- /* dequeue from mru list and put to free list */
- md->mru_prev->mru_next = md->mru_next;
- md->mru_next->mru_prev = md->mru_prev;
- remove_from_hash(md);
- md->hash_next = mon_free;
- mon_free = md;
- }
- }
- }
- /*
- * ntp_monitor - record stats about this packet
- *
- * Returns 1 if the packet is at the head of the list, 0 otherwise.
- */
- int
- ntp_monitor(
- struct recvbuf *rbufp
- )
- {
- register struct pkt *pkt;
- register struct mon_data *md;
- struct sockaddr_storage addr;
- register int hash;
- register int mode;
- if (mon_enabled == MON_OFF)
- return 0;
- pkt = &rbufp->recv_pkt;
- memset(&addr, 0, sizeof(addr));
- memcpy(&addr, &(rbufp->recv_srcadr), sizeof(addr));
- hash = MON_HASH(&addr);
- mode = PKT_MODE(pkt->li_vn_mode);
- md = mon_hash[hash];
- while (md != NULL) {
- /*
- * Match address only to conserve MRU size.
- */
- if (SOCKCMP(&md->rmtadr, &addr)) {
- md->drop_count = current_time - md->lasttime;
- md->lasttime = current_time;
- md->count++;
- md->rmtport = NSRCPORT(&rbufp->recv_srcadr);
- md->mode = (u_char) mode;
- md->version = PKT_VERSION(pkt->li_vn_mode);
- /*
- * Shuffle to the head of the MRU list.
- */
- md->mru_next->mru_prev = md->mru_prev;
- md->mru_prev->mru_next = md->mru_next;
- md->mru_next = mon_mru_list.mru_next;
- md->mru_prev = &mon_mru_list;
- mon_mru_list.mru_next->mru_prev = md;
- mon_mru_list.mru_next = md;
- return 1;
- }
- md = md->hash_next;
- }
- /*
- * If we got here, this is the first we've heard of this
- * guy. Get him some memory, either from the free list
- * or from the tail of the MRU list.
- */
- if (mon_free == NULL && mon_total_mem >= MAXMONMEM) {
- /*
- * Preempt from the MRU list if old enough.
- */
- md = mon_mru_list.mru_prev;
- /* We get 31 bits from ntp_random() */
- if (((u_long)ntp_random()) / FRAC >
- (double)(current_time - md->lasttime) / mon_age)
- return 0;
- md->mru_prev->mru_next = &mon_mru_list;
- mon_mru_list.mru_prev = md->mru_prev;
- remove_from_hash(md);
- } else {
- if (mon_free == NULL)
- mon_getmoremem();
- md = mon_free;
- mon_free = md->hash_next;
- }
- /*
- * Got one, initialize it
- */
- md->avg_interval = 0;
- md->lasttime = current_time;
- md->count = 1;
- md->drop_count = 0;
- memset(&md->rmtadr, 0, sizeof(md->rmtadr));
- memcpy(&md->rmtadr, &addr, sizeof(addr));
- md->rmtport = NSRCPORT(&rbufp->recv_srcadr);
- md->mode = (u_char) mode;
- md->version = PKT_VERSION(pkt->li_vn_mode);
- md->interface = rbufp->dstadr;
- md->cast_flags = (u_char)(((rbufp->dstadr->flags & INT_MCASTOPEN) &&
- rbufp->fd == md->interface->fd) ? MDF_MCAST: rbufp->fd ==
- md->interface->bfd ? MDF_BCAST : MDF_UCAST);
- /*
- * Drop him into front of the hash table. Also put him on top of
- * the MRU list.
- */
- md->hash_next = mon_hash[hash];
- mon_hash[hash] = md;
- md->mru_next = mon_mru_list.mru_next;
- md->mru_prev = &mon_mru_list;
- mon_mru_list.mru_next->mru_prev = md;
- mon_mru_list.mru_next = md;
- return 1;
- }
- /*
- * mon_getmoremem - get more memory and put it on the free list
- */
- static void
- mon_getmoremem(void)
- {
- register struct mon_data *md;
- register int i;
- struct mon_data *freedata; /* 'old' free list (null) */
- md = (struct mon_data *)emalloc(MONMEMINC *
- sizeof(struct mon_data));
- freedata = mon_free;
- mon_free = md;
- for (i = 0; i < (MONMEMINC-1); i++) {
- md->hash_next = (md + 1);
- md++;
- }
- /*
- * md now points at the last. Link in the rest of the chain.
- */
- md->hash_next = freedata;
- mon_total_mem += MONMEMINC;
- mon_mem_increments++;
- }
- static void
- remove_from_hash(
- struct mon_data *md
- )
- {
- register int hash;
- register struct mon_data *md_prev;
- hash = MON_HASH(&md->rmtadr);
- if (mon_hash[hash] == md) {
- mon_hash[hash] = md->hash_next;
- } else {
- md_prev = mon_hash[hash];
- while (md_prev->hash_next != md) {
- md_prev = md_prev->hash_next;
- if (md_prev == NULL) {
- /* logic error */
- return;
- }
- }
- md_prev->hash_next = md->hash_next;
- }
- }