turns printfs back on

[freebsd-src/fkvm-freebsd.git] / contrib / ntp / ntpd / ntp_restrict.c

/*
 * ntp_restrict.c - determine host restrictions
 */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <sys/types.h>

#include "ntpd.h"
#include "ntp_if.h"
#include "ntp_stdlib.h"

/*
 * This code keeps a simple address-and-mask list of hosts we want
 * to place restrictions on (or remove them from). The restrictions
 * are implemented as a set of flags which tell you what the host
 * can't do. There is a subroutine entry to return the flags. The
 * list is kept sorted to reduce the average number of comparisons
 * and make sure you get the set of restrictions most specific to
 * the address.
 *
 * The algorithm is that, when looking up a host, it is first assumed
 * that the default set of restrictions will apply. It then searches
 * down through the list. Whenever it finds a match it adopts the
 * match's flags instead. When you hit the point where the sorted
 * address is greater than the target, you return with the last set of
 * flags you found. Because of the ordering of the list, the most
 * specific match will provide the final set of flags.
 *
 * This was originally intended to restrict you from sync'ing to your
 * own broadcasts when you are doing that, by restricting yourself from
 * your own interfaces. It was also thought it would sometimes be useful
 * to keep a misbehaving host or two from abusing your primary clock. It
 * has been expanded, however, to suit the needs of those with more
 * restrictive access policies.
 */
/*
 * We will use two lists, one for IPv4 addresses and one for IPv6
 * addresses. This is not protocol-independant but for now I can't
 * find a way to respect this. We'll check this later... JFB 07/2001
 */
#define SET_IPV6_ADDR_MASK(dst, src, msk) \
        do { \
                int idx; \
                for (idx = 0; idx < 16; idx++) { \
                        (dst)->s6_addr[idx] = \
                            (u_char) ((src)->s6_addr[idx] & (msk)->s6_addr[idx]); \
                } \
        } while (0)

/*
 * Memory allocation parameters.  We allocate INITRESLIST entries
 * initially, and add INCRESLIST entries to the free list whenever
 * we run out.
 */
#define INITRESLIST     10
#define INCRESLIST      5

#define RES_AVG         8.      /* interpacket averaging factor */

/*
 * The restriction list
 */
struct restrictlist *restrictlist;
struct restrictlist6 *restrictlist6;
static  int restrictcount;      /* count of entries in the res list */
static  int restrictcount6;     /* count of entries in the res list 2*/

/*
 * The free list and associated counters.  Also some uninteresting
 * stat counters.
 */
static  struct restrictlist *resfree;
static  struct restrictlist6 *resfree6;
static  int numresfree;         /* number of structures on free list */
static  int numresfree6;        /* number of structures on free list 2 */

static  u_long res_calls;
static  u_long res_found;
static  u_long res_not_found;

/*
 * Parameters of the RES_LIMITED restriction option.
 */
u_long res_avg_interval = 5;    /* min average interpacket interval */
u_long res_min_interval = 1;    /* min interpacket interval */

/*
 * Count number of restriction entries referring to RES_LIMITED controls
 * activation/deactivation of monitoring (with respect to RES_LIMITED
 * control)
 */
static  u_long res_limited_refcnt;
static  u_long res_limited_refcnt6;

/*
 * Our initial allocation of lists entries.
 */
static  struct restrictlist resinit[INITRESLIST];
static  struct restrictlist6 resinit6[INITRESLIST];

/*
 * init_restrict - initialize the restriction data structures
 */
void
init_restrict(void)
{
        register int i;

        /*
         * Zero the list and put all but one on the free list
         */
        resfree = NULL;
        memset((char *)resinit, 0, sizeof resinit);
        resfree6 = NULL;
        memset((char *)resinit6, 0, sizeof resinit6);
        for (i = 1; i < INITRESLIST; i++) {
                resinit[i].next = resfree;
                resinit6[i].next = resfree6;
                resfree = &resinit[i];
                resfree6 = &resinit6[i];
        }
        numresfree = INITRESLIST-1;
        numresfree6 = INITRESLIST-1;

        /*
         * Put the remaining item at the head of the list as our default
         * entry. Everything in here should be zero for now.
         */
        resinit[0].addr = htonl(INADDR_ANY);
        resinit[0].mask = 0;
        memset(&resinit6[0].addr6, 0, sizeof(struct in6_addr)); 
        memset(&resinit6[0].mask6, 0, sizeof(struct in6_addr)); 
        restrictlist = &resinit[0];
        restrictlist6 = &resinit6[0];
        restrictcount = 1;
        restrictcount = 2;

        /*
         * fix up stat counters
         */
        res_calls = 0;
        res_found = 0;
        res_not_found = 0;

        /*
         * set default values for RES_LIMIT functionality
         */
        res_limited_refcnt = 0;
        res_limited_refcnt6 = 0;
}


/*
 * restrictions - return restrictions for this host
 */
int
restrictions(
        struct sockaddr_storage *srcadr,
        int at_listhead
        )
{
        struct restrictlist *rl;
        struct restrictlist *match = NULL;
        struct restrictlist6 *rl6;
        struct restrictlist6 *match6 = NULL;
        struct in6_addr hostaddr6;
        struct in6_addr hostservaddr6;
        u_int32 hostaddr;
        int     flags = 0;
        int     isntpport;

        res_calls++;
        if (srcadr->ss_family == AF_INET) {
                /*
                 * We need the host address in host order.  Also need to
                 * know whether this is from the ntp port or not.
                 */
                hostaddr = SRCADR(srcadr);
                isntpport = (SRCPORT(srcadr) == NTP_PORT);

                /*
                 * Ignore any packets with a multicast source address
                 * (this should be done early in the receive process,
                 * later!)
                 */
                if (IN_CLASSD(SRCADR(srcadr)))
                        return (int)RES_IGNORE;

                /*
                 * Set match to first entry, which is default entry.
                 * Work our way down from there.
                 */
                match = restrictlist;
                for (rl = match->next; rl != NULL && rl->addr <= hostaddr;
                    rl = rl->next)
                        if ((hostaddr & rl->mask) == rl->addr) {
                                if ((rl->mflags & RESM_NTPONLY) &&
                                    !isntpport)
                                        continue;
                                match = rl;
                        }
                match->count++;
                if (match == restrictlist)
                        res_not_found++;
                else
                        res_found++;
                flags = match->flags;
        }

        /* IPv6 source address */
        if (srcadr->ss_family == AF_INET6) {
                /*
                 * Need to know whether this is from the ntp port or
                 * not.
                 */
                hostaddr6 = GET_INADDR6(*srcadr);
                isntpport = (ntohs((
                    (struct sockaddr_in6 *)srcadr)->sin6_port) ==
                    NTP_PORT);

                /*
                 * Ignore any packets with a multicast source address
                 * (this should be done early in the receive process,
                 * later!)
                 */
                if (IN6_IS_ADDR_MULTICAST(&hostaddr6))
                        return (int)RES_IGNORE;

                /*
                 * Set match to first entry, which is default entry.
                 *  Work our way down from there.
                 */
                match6 = restrictlist6;
                for (rl6 = match6->next; rl6 != NULL &&
                    (memcmp(&(rl6->addr6), &hostaddr6,
                    sizeof(hostaddr6)) <= 0); rl6 = rl6->next) {
                        SET_IPV6_ADDR_MASK(&hostservaddr6, &hostaddr6,
                            &rl6->mask6);
                        if (memcmp(&hostservaddr6, &(rl6->addr6),
                            sizeof(hostservaddr6)) == 0) {
                                if ((rl6->mflags & RESM_NTPONLY) &&
                                    !isntpport)
                                        continue;
                                match6 = rl6;
                        }
                }
                match6->count++;
                if (match6 == restrictlist6)
                        res_not_found++;
                else
                        res_found++;
                flags = match6->flags;
        }

        /*
         * The following implements a generalized call gap facility.
         * Douse the RES_LIMITED bit only if the interval since the last
         * packet is greater than res_min_interval and the average is
         * greater thatn res_avg_interval.
         */
        if (!at_listhead || mon_enabled == MON_OFF) {
                flags &= ~RES_LIMITED;
        } else {
                struct mon_data *md;

                /*
                 * At this poin the most recent arrival is first in the
                 * MRU list. Let the first 10 packets in for free until
                 * the average stabilizes.
                 */
                md = mon_mru_list.mru_next;
                if (md->avg_interval == 0)
                        md->avg_interval = md->drop_count;
                else
                        md->avg_interval += (md->drop_count -
                            md->avg_interval) / RES_AVG;
                if (md->count < 10 || (md->drop_count >
                    res_min_interval && md->avg_interval >
                    res_avg_interval))
                        flags &= ~RES_LIMITED;
                md->drop_count = flags;
        }
        return (flags);
}


/*
 * hack_restrict - add/subtract/manipulate entries on the restrict list
 */
void
hack_restrict(
        int op,
        struct sockaddr_storage *resaddr,
        struct sockaddr_storage *resmask,
        int mflags,
        int flags
        )
{
        register u_int32 addr = 0;
        register u_int32 mask = 0;
        struct in6_addr addr6;
        struct in6_addr mask6;
        register struct restrictlist *rl = NULL;
        register struct restrictlist *rlprev = NULL;
        register struct restrictlist6 *rl6 = NULL;
        register struct restrictlist6 *rlprev6 = NULL;
        int i, addr_cmp, mask_cmp;
        memset(&addr6, 0, sizeof(struct in6_addr)); 
        memset(&mask6, 0, sizeof(struct in6_addr)); 

        if (resaddr->ss_family == AF_INET) {
                /*
                 * Get address and mask in host byte order
                 */
                addr = SRCADR(resaddr);
                mask = SRCADR(resmask);
                addr &= mask;           /* make sure low bits zero */

                /*
                 * If this is the default address, point at first on
                 * list. Else go searching for it.
                 */
                if (addr == 0) {
                        rlprev = NULL;
                        rl = restrictlist;
                } else {
                        rlprev = restrictlist;
                        rl = rlprev->next;
                        while (rl != NULL) {
                                if (rl->addr > addr) {
                                        rl = NULL;
                                        break;
                                } else if (rl->addr == addr) {
                                        if (rl->mask == mask) {
                                                if ((mflags &
                                                    RESM_NTPONLY) ==
                                                    (rl->mflags &
                                                    RESM_NTPONLY))
                                                        break;

                                                if (!(mflags &
                                                    RESM_NTPONLY)) {
                                                        rl = NULL;
                                                        break;
                                                }
                                        } else if (rl->mask > mask) {
                                                rl = NULL;
                                                break;
                                        }
                                }
                                rlprev = rl;
                                rl = rl->next;
                        }
                }
        }

        if (resaddr->ss_family == AF_INET6) {
                mask6 = GET_INADDR6(*resmask);
                SET_IPV6_ADDR_MASK(&addr6,
                    &GET_INADDR6(*resaddr), &mask6);
                if (IN6_IS_ADDR_UNSPECIFIED(&addr6)) {
                        rlprev6 = NULL;
                        rl6 = restrictlist6;
                } else {
                        rlprev6 = restrictlist6;
                        rl6 = rlprev6->next;
                        while (rl6 != NULL) {
                                addr_cmp = memcmp(&rl6->addr6, &addr6,
                                    sizeof(addr6));
                                if (addr_cmp > 0) {
                                        rl6 = NULL;
                                        break;
                                } else if (addr_cmp == 0) {
                                        mask_cmp = memcmp(&rl6->mask6,
                                            &mask6, sizeof(mask6));
                                        if (mask_cmp == 0) {
                                                if ((mflags &
                                                    RESM_NTPONLY) ==
                                                    (rl6->mflags &
                                                    RESM_NTPONLY))
                                                        break;

                                                if (!(mflags &
                                                    RESM_NTPONLY)) {
                                                        rl6 = NULL;
                                                        break;
                                                }
                                        } else if (mask_cmp > 0) {
                                                rl6 = NULL;
                                                break;
                                        }
                                }
                                rlprev6 = rl6;
                                rl6 = rl6->next;
                        }
                }
        }

        /*
         * In case the above wasn't clear :-), either rl now points
         * at the entry this call refers to, or rl is zero and rlprev
         * points to the entry prior to where this one should go in
         * the sort.
         */

        /*
         * Switch based on operation
         */
        if (resaddr->ss_family == AF_INET) {
                switch (op) {
                case RESTRICT_FLAGS:
                        /*
                         * Here we add bits to the flags. If this is a
                         * new restriction add it.
                         */
                        if (rl == NULL) {
                                if (resfree == NULL) {
                                        rl = (struct restrictlist *)
                                            emalloc(INCRESLIST *
                                            sizeof(struct
                                            restrictlist));
                                        memset((char *)rl, 0,
                                            INCRESLIST * sizeof(struct
                                            restrictlist));
                                        for (i = 0; i < INCRESLIST; i++) {
                                                rl->next = resfree;
                                                resfree = rl;
                                                rl++;
                                        }
                                        numresfree = INCRESLIST;
                                }

                                rl = resfree;
                                resfree = rl->next;
                                numresfree--;

                                rl->addr = addr;
                                rl->mask = mask;
                                rl->mflags = (u_short)mflags;

                                if (rlprev == NULL) {
                                        rl->next = restrictlist;
                                        restrictlist = rl;
                                } else {
                                        rl->next = rlprev->next;
                                        rlprev->next = rl;
                                }
                                restrictcount++;
                        }
                        if ((rl->flags ^ (u_short)flags) &
                            RES_LIMITED) {
                                res_limited_refcnt++;
                                mon_start(MON_RES);
                        }
                        rl->flags |= (u_short)flags;
                        break;

                case RESTRICT_UNFLAG:
                        /*
                         * Remove some bits from the flags. If we didn't
                         * find this one, just return.
                         */
                        if (rl != NULL) {
                                if ((rl->flags ^ (u_short)flags) &
                                    RES_LIMITED) {
                                        res_limited_refcnt--;
                                        if (res_limited_refcnt == 0)
                                                mon_stop(MON_RES);
                                }
                                rl->flags &= (u_short)~flags;
                        }
                        break;
        
                case RESTRICT_REMOVE:
                case RESTRICT_REMOVEIF:
                        /*
                         * Remove an entry from the table entirely if we
                         * found one. Don't remove the default entry and
                         * don't remove an interface entry.
                         */
                        if (rl != NULL
                            && rl->addr != htonl(INADDR_ANY)
                            && !(rl->mflags & RESM_INTERFACE && op != RESTRICT_REMOVEIF)) {
                                if (rlprev != NULL) {
                                        rlprev->next = rl->next;
                                } else {
                                        restrictlist = rl->next;
                                }
                                restrictcount--;
                                if (rl->flags & RES_LIMITED) {
                                        res_limited_refcnt--;
                                        if (res_limited_refcnt == 0)
                                                mon_stop(MON_RES);
                                }
                                memset((char *)rl, 0,
                                    sizeof(struct restrictlist));

                                rl->next = resfree;
                                resfree = rl;
                                numresfree++;
                        }
                        break;

                default:
                        break;
                }
        } else if (resaddr->ss_family == AF_INET6) {
                switch (op) {
                case RESTRICT_FLAGS:
                        /*
                         * Here we add bits to the flags. If this is a
                         * new restriction add it.
                         */
                        if (rl6 == NULL) {
                                if (resfree6 == NULL) {
                                        rl6 = (struct
                                            restrictlist6 *)emalloc(
                                            INCRESLIST * sizeof(struct
                                            restrictlist6));
                                        memset((char *)rl6, 0,
                                            INCRESLIST * sizeof(struct
                                            restrictlist6));

                                        for (i = 0; i < INCRESLIST;
                                            i++) {
                                                rl6->next = resfree6;
                                                resfree6 = rl6;
                                                rl6++;
                                        }
                                        numresfree6 = INCRESLIST;
                                }
                                rl6 = resfree6;
                                resfree6 = rl6->next;
                                numresfree6--;
                                rl6->addr6 = addr6;
                                rl6->mask6 = mask6;
                                rl6->mflags = (u_short)mflags;
                                if (rlprev6 != NULL) {
                                        rl6->next = rlprev6->next;
                                        rlprev6->next = rl6;
                                } else {
                                        rl6->next = restrictlist6;
                                        restrictlist6 = rl6;
                                }
                                restrictcount6++;
                        }
                        if ((rl6->flags ^ (u_short)flags) &
                            RES_LIMITED) {
                                res_limited_refcnt6++;
                                mon_start(MON_RES);
                        }
                        rl6->flags |= (u_short)flags;
                        break;

                case RESTRICT_UNFLAG:
                        /*
                         * Remove some bits from the flags. If we didn't
                         * find this one, just return.
                         */
                        if (rl6 != NULL) {
                                if ((rl6->flags ^ (u_short)flags) &
                                    RES_LIMITED) {
                                        res_limited_refcnt6--;
                                        if (res_limited_refcnt6 == 0)
                                                mon_stop(MON_RES);
                                }
                                rl6->flags &= (u_short)~flags;
                        }
                        break;

                case RESTRICT_REMOVE:
                case RESTRICT_REMOVEIF:
                        /*
                         * Remove an entry from the table entirely if we
                         * found one. Don't remove the default entry and
                         * don't remove an interface entry.
                         */
                        if (rl6 != NULL &&
                            !IN6_IS_ADDR_UNSPECIFIED(&rl6->addr6)
                            && !(rl6->mflags & RESM_INTERFACE && op != RESTRICT_REMOVEIF)) {
                                if (rlprev6 != NULL) {
                                        rlprev6->next = rl6->next;
                                } else {
                                        restrictlist6 = rl6->next;
                                }
                                restrictcount6--;
                                if (rl6->flags & RES_LIMITED) {
                                        res_limited_refcnt6--;
                                        if (res_limited_refcnt6 == 0)
                                                mon_stop(MON_RES);
                                }
                                memset((char *)rl6, 0,
                                    sizeof(struct restrictlist6));
                                rl6->next = resfree6;
                                resfree6 = rl6;
                                numresfree6++;
                        }
                        break;

                default:
                        break;
                }
        }
}