/* * ntp_monitor.c - monitor who is using the ntpd server */ #ifdef HAVE_CONFIG_H #include #endif #include #include #include # ifdef HAVE_SYS_IOCTL_H # include # endif # include #include "ntpd.h" #include "ntp_io.h" #include "ntp_if.h" #include "ntp_stdlib.h" /* * 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) ((int)(ntohl((addr)) & MON_HASH_MASK)) /* * 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]; /* array of list ptrs */ struct mon_data mon_mru_list; struct mon_data mon_fifo_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; /* the free list or null if none */ static int mon_total_mem; /* total number of structures allocated */ static int mon_mem_increments; /* number of times we've 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; 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((char *)&mon_hash[0], 0, sizeof mon_hash); memset((char *)&mon_mru_list, 0, sizeof mon_mru_list); memset((char *)&mon_fifo_list, 0, sizeof mon_fifo_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; /* Ooops.. */ 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_fifo_list.fifo_next = &mon_fifo_list; mon_fifo_list.fifo_prev = &mon_fifo_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; mon_fifo_list.fifo_next = &mon_fifo_list; mon_fifo_list.fifo_prev = &mon_fifo_list; } /* * ntp_monitor - record stats about this packet */ void ntp_monitor( struct recvbuf *rbufp ) { register struct pkt *pkt; register struct mon_data *md; register u_long netnum; register int hash; register int mode; if (mon_enabled == MON_OFF) return; pkt = &rbufp->recv_pkt; netnum = NSRCADR(&rbufp->recv_srcadr); hash = MON_HASH(netnum); mode = PKT_MODE(pkt->li_vn_mode); md = mon_hash[hash]; while (md != NULL) { if (md->rmtadr == netnum && /* ?? md->interface == rbufp->dstadr && ?? */ md->mode == (u_char)mode) { md->lasttime = current_time; md->count++; md->version = PKT_VERSION(pkt->li_vn_mode); md->rmtport = NSRCPORT(&rbufp->recv_srcadr); /* * Shuffle him to the head of the * mru list. What a crock. */ 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; } 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) { /* * Get it from MRU list */ md = mon_mru_list.mru_prev; md->mru_prev->mru_next = &mon_mru_list; mon_mru_list.mru_prev = md->mru_prev; remove_from_hash(md); /* * Get it from FIFO list */ md->fifo_prev->fifo_next = md->fifo_next; md->fifo_next->fifo_prev = md->fifo_prev; } else { if (mon_free == NULL) /* if free list empty */ mon_getmoremem(); /* then get more */ md = mon_free; mon_free = md->hash_next; } /* * Got one, initialize it */ md->lasttime = md->firsttime = current_time; md->lastdrop = 0; md->count = 1; md->rmtadr = netnum; 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 = ((rbufp->dstadr->flags & INT_MULTICAST) && 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 * and at bottom of FIFO 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; md->fifo_prev = mon_fifo_list.fifo_prev; md->fifo_next = &mon_fifo_list; mon_fifo_list.fifo_prev->fifo_next = md; mon_fifo_list.fifo_prev = md; } /* * 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; } }