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