/*      $OpenBSD: sdl.c,v 1.25 2022/12/26 20:06:43 jmc Exp $ */

/*
 * Copyright (c) 2003-2007 Bob Beck.  All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * sdl.c - Implement spamd source lists
 *
 * This consists of everything we need to do to determine which lists
 * someone is on. Spamd gets the connecting address, and looks it up
 * against all lists to determine what deferral messages to feed back
 * to the connecting machine. - The redirection to spamd will happen
 * from pf in the kernel, first match will divert to us. Spamd (along with
 * setup) must keep track of *all* matches, so as to tell someone all the
 * lists that they are on.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "sdl.h"

static void sdl_free(struct sdlist *);
static void sdl_clear(struct sdlist *);

extern int debug;
struct sdlist *blacklists = NULL;
int blc = 0, blu = 0;

static int
compar_v4(const void *va, const void *vb)
{
        const struct sdentry_v4 *a = va;
        const struct sdentry_v4 *b = vb;
        struct in_addr aa;
        struct in_addr bb;

        /* The mask has already been applied. */
        aa.s_addr = ntohl(a->sda.s_addr);
        bb.s_addr = ntohl(b->sda.s_addr);

        if (aa.s_addr > bb.s_addr)
                return (1);
        if (aa.s_addr < bb.s_addr)
                return (-1);
        return (0);
}

static int
compar_v6(const void *va, const void *vb)
{
        const struct sdentry_v6 *a = va;
        const struct sdentry_v6 *b = vb;
        struct sdaddr_v6 aa;
        struct sdaddr_v6 bb;

        /* The mask has already been applied. */
        aa.addr32[0] = ntohl(a->sda.addr32[0]);
        aa.addr32[1] = ntohl(a->sda.addr32[1]);
        aa.addr32[2] = ntohl(a->sda.addr32[2]);
        aa.addr32[3] = ntohl(a->sda.addr32[3]);

        bb.addr32[0] = ntohl(b->sda.addr32[0]);
        bb.addr32[1] = ntohl(b->sda.addr32[1]);
        bb.addr32[2] = ntohl(b->sda.addr32[2]);
        bb.addr32[3] = ntohl(b->sda.addr32[3]);

        if (aa.addr32[0] > bb.addr32[0])
                return (1);
        if (aa.addr32[0] < bb.addr32[0])
                return (-1);
        if (aa.addr32[1] > bb.addr32[1])
                return (1);
        if (aa.addr32[1] < bb.addr32[1])
                return (-1);
        if (aa.addr32[2] > bb.addr32[2])
                return (1);
        if (aa.addr32[2] < bb.addr32[2])
                return (-1);
        if (aa.addr32[3] > bb.addr32[3])
                return (1);
        if (aa.addr32[3] < bb.addr32[3])
                return (-1);
        return (0);
}

int
sdl_add(char *sdname, char *sdstring, char **v4, u_int nv4, char **v6, u_int nv6)
{
        int i, idx = -1;
        char astring[40];
        char *addr = NULL;
        unsigned int maskbits;

        /*
         * if a blacklist of same tag name is already there, replace it,
         * otherwise append.
         */
        for (i = 0; i < blu; i++) {
                if (strcmp(blacklists[i].tag, sdname) == 0) {
                        idx = i;
                        break;
                }
        }
        if (idx != -1) {
                if (debug > 0)
                        printf("replacing list %s; %u new entries\n",
                            blacklists[idx].tag, nv4 + nv6);
                sdl_free(&blacklists[idx]);
        } else {
                if (debug > 0)
                        printf("adding list %s; %u entries\n", sdname, nv4 + nv6);
                if (blu == blc) {
                        struct sdlist *tmp;

                        tmp = reallocarray(blacklists, blc + 128,
                            sizeof(struct sdlist));
                        if (tmp == NULL)
                                return (-1);
                        blacklists = tmp;
                        blc += 128;
                        sdl_clear(&blacklists[blu]);
                }
                idx = blu;
        }

        if ((blacklists[idx].tag = strdup(sdname)) == NULL)
                goto misc_error;
        if ((blacklists[idx].string = strdup(sdstring)) == NULL)
                goto misc_error;

        /*
         * Cycle through addrs by family, converting. We assume they are
         * correctly formatted v4 and v6 addrs, if they don't all convert
         * correctly, the add fails. Each address should be address/maskbits.
         */
        if (nv4 != 0) {
                blacklists[idx].v4.naddrs = nv4;
                blacklists[idx].v4.addrs = reallocarray(NULL, nv4,
                    sizeof(struct sdentry_v4));
                if (blacklists[idx].v4.addrs == NULL)
                        goto misc_error;
                for (i = 0; i < nv4; i++) {
                        struct in_addr *m, *n;
                        int j;

                        n = &blacklists[idx].v4.addrs[i].sda;
                        m = &blacklists[idx].v4.addrs[i].sdm;

                        addr = v4[i];
                        j = sscanf(addr, "%15[^/]/%u", astring, &maskbits);
                        if (j != 2)
                                goto parse_error;
                        /*
                         * sanity check! we don't allow a 0 mask -
                         * don't blacklist the entire net.
                         */
                        if (maskbits == 0 || maskbits > 32)
                                goto parse_error;
                        j = inet_pton(AF_INET, astring, n);
                        if (j != 1)
                                goto parse_error;
                        if (debug > 0)
                                printf("added %s/%u\n", astring, maskbits);

                        /* set mask. */
                        m->s_addr = 0xffffffffU << (32 - maskbits);
                        m->s_addr = htonl(m->s_addr);

                        /* mask off address bits that won't ever be used */
                        n->s_addr = n->s_addr & m->s_addr;
                }
                /* spamd-setup output is sorted in host byte order */
                mergesort(blacklists[idx].v4.addrs, nv4,
                    sizeof(struct sdentry_v4), compar_v4);
        }
        if (nv6 != 0) {
                blacklists[idx].v6.naddrs = nv6;
                blacklists[idx].v6.addrs = reallocarray(NULL, nv6,
                    sizeof(struct sdentry_v6));
                if (blacklists[idx].v6.addrs == NULL)
                        goto misc_error;

                for (i = 0; i < nv6; i++) {
                        int j, k;
                        struct sdaddr_v6 *m, *n;

                        n = &blacklists[idx].v6.addrs[i].sda;
                        m = &blacklists[idx].v6.addrs[i].sdm;

                        addr = v6[i];
                        j = sscanf(addr, "%39[^/]/%u", astring, &maskbits);
                        if (j != 2)
                                goto parse_error;
                        /*
                         * sanity check! we don't allow a 0 mask -
                         * don't blacklist the entire net.
                         */
                        if (maskbits == 0 || maskbits > 128)
                                goto parse_error;
                        j = inet_pton(AF_INET6, astring, n);
                        if (j != 1)
                                goto parse_error;
                        if (debug > 0)
                                printf("added %s/%u\n", astring, maskbits);

                        /* set mask, borrowed from pf */
                        k = 0;
                        for (j = 0; j < 4; j++)
                                m->addr32[j] = 0;
                        while (maskbits >= 32) {
                                m->addr32[k++] = 0xffffffffU;
                                maskbits -= 32;
                        }
                        for (j = 31; j > 31 - maskbits; --j)
                                m->addr32[k] |= (1 << j);
                        if (maskbits)
                                m->addr32[k] = htonl(m->addr32[k]);

                        /* mask off address bits that won't ever be used */
                        for (j = 0; j < 4; j++)
                                n->addr32[j] = n->addr32[j] & m->addr32[j];
                }
                /* spamd-setup output is sorted in host byte order */
                mergesort(blacklists[idx].v6.addrs, nv6,
                    sizeof(struct sdentry_v6), compar_v6);
        }
        if (idx == blu) {
                blu++;
                sdl_clear(&blacklists[blu]);
        }
        return (0);
 parse_error:
        if (debug > 0)
                printf("sdl_add: parse error, \"%s\"\n", addr);
 misc_error:
        sdl_free(&blacklists[idx]);
        if (idx != blu) {
                memmove(&blacklists[idx], &blacklists[idx + 1],
                    (blu - idx) * sizeof(*blacklists));
                blu--;
        }
        return (-1);
}

void
sdl_del(char *sdname)
{
        int i, idx = -1;

        for (i = 0; i < blu; i++) {
                if (strcmp(blacklists[i].tag, sdname) == 0) {
                        idx = i;
                        break;
                }
        }
        if (idx != -1) {
                if (debug > 0)
                        printf("clearing list %s\n", sdname);
                /* Must preserve tag. */
                free(blacklists[idx].string);
                free(blacklists[idx].v4.addrs);
                free(blacklists[idx].v6.addrs);
                blacklists[idx].string = NULL;
                blacklists[idx].v4.addrs = NULL;
                blacklists[idx].v6.addrs = NULL;
                blacklists[idx].v4.naddrs = 0;
                blacklists[idx].v6.naddrs = 0;
        }
}

/*
 * Return 0 if the address a (with mask m) matches address key
 * otherwise return 1 if a > key or -1 if a < key.  It is assumed
 * that address a has been pre-masked out, we only need to mask key.
 */
static int
match_addr_v4(const void *vkey, const void *ventry)
{
        const struct in_addr *k = vkey;
        const struct in_addr *a = &((const struct sdentry_v4 *)ventry)->sda;
        const struct in_addr *m = &((const struct sdentry_v4 *)ventry)->sdm;
        struct in_addr kk;
        struct in_addr aa;

        kk.s_addr = ntohl(k->s_addr & m->s_addr);
        aa.s_addr = ntohl(a->s_addr);
        if (kk.s_addr > aa.s_addr)
                return (1);
        if (kk.s_addr < aa.s_addr)
                return (-1);
        return (0);
}

/*
 * Return 0 if the address a (with mask m) matches address key
 * otherwise return 1 if a > key or -1 if a < key.  It is assumed
 * that address a has been pre-masked out, we only need to mask key.
 */
static int
match_addr_v6(const void *vkey, const void *ventry)
{
        const struct sdaddr_v6 *k = vkey;
        const struct sdaddr_v6 *a = &((const struct sdentry_v6 *)ventry)->sda;
        const struct sdaddr_v6 *m = &((const struct sdentry_v6 *)ventry)->sdm;
        struct sdaddr_v6 kk;
        struct sdaddr_v6 aa;

        kk.addr32[0] = ntohl(k->addr32[0] & m->addr32[0]);
        kk.addr32[1] = ntohl(k->addr32[1] & m->addr32[1]);
        kk.addr32[2] = ntohl(k->addr32[2] & m->addr32[2]);
        kk.addr32[3] = ntohl(k->addr32[3] & m->addr32[3]);

        aa.addr32[0] = ntohl(a->addr32[0]);
        aa.addr32[1] = ntohl(a->addr32[1]);
        aa.addr32[2] = ntohl(a->addr32[2]);
        aa.addr32[3] = ntohl(a->addr32[3]);

        if (kk.addr32[0] > aa.addr32[0])
                return (1);
        if (kk.addr32[0] < aa.addr32[0])
                return (-1);
        if (kk.addr32[1] > aa.addr32[1])
                return (1);
        if (kk.addr32[1] < aa.addr32[1])
                return (-1);
        if (kk.addr32[2] > aa.addr32[2])
                return (1);
        if (kk.addr32[2] < aa.addr32[2])
                return (-1);
        if (kk.addr32[3] > aa.addr32[3])
                return (1);
        if (kk.addr32[3] < aa.addr32[3])
                return (-1);
        return (0);
}

#define grow_sdlist(sd, c, l) do {                                             \
        if (c == l) {                                                          \
                struct sdlist **tmp;                                           \
                                                                               \
                tmp = reallocarray(sd, l + 128, sizeof(struct sdlist *));      \
                if (tmp == NULL) {                                             \
                        /*                                                     \
                         * XXX out of memory - return what we have             \
                         */                                                    \
                        return (sdnew);                                        \
                }                                                              \
                sd = tmp;                                                      \
                l += 128;                                                      \
        }                                                                      \
} while (0)

static struct sdlist **
sdl_lookup_v4(struct sdlist *sdl, struct in_addr *src)
{
        int matches = 0;
        int sdnewlen = 0;
        struct sdlist **sdnew = NULL;

        while (sdl->tag != NULL) {
                if (bsearch(src, sdl->v4.addrs, sdl->v4.naddrs,
                    sizeof(struct sdentry_v4), match_addr_v4) != NULL) {
                        grow_sdlist(sdnew, matches, sdnewlen);
                        sdnew[matches] = sdl;
                        matches++;
                        sdnew[matches] = NULL;
                        break;
                }
                sdl++;
        }
        return (sdnew);
}

static struct sdlist **
sdl_lookup_v6(struct sdlist *sdl, struct sdaddr_v6 *src)
{
        int matches = 0;
        int sdnewlen = 0;
        struct sdlist **sdnew = NULL;

        while (sdl->tag != NULL) {
                if (bsearch(src, sdl->v6.addrs, sdl->v6.naddrs,
                    sizeof(struct sdentry_v6), match_addr_v6) != NULL) {
                        grow_sdlist(sdnew, matches, sdnewlen);
                        sdnew[matches] = sdl;
                        matches++;
                        sdnew[matches] = NULL;
                        break;
                }
                sdl++;
        }
        return (sdnew);
}

/*
 * Given an address and address family
 * return list of pointers to matching nodes. or NULL if none.
 */
struct sdlist **
sdl_lookup(struct sdlist *head, int af, void *src)
{
        if (head == NULL)
                return (NULL);

        switch (af) {
        case AF_INET:
                return (sdl_lookup_v4(head, src));
        case AF_INET6:
                return (sdl_lookup_v6(head, src));
        default:
                return (NULL);
        }
}

static int
sdl_check_v4(struct sdlist *sdl, struct in_addr *src)
{
        while (sdl->tag != NULL) {
                if (bsearch(src, sdl->v4.addrs, sdl->v4.naddrs,
                    sizeof(struct sdentry_v4), match_addr_v4) != NULL)
                        return (1);
                sdl++;
        }
        return (0);
}

static int
sdl_check_v6(struct sdlist *sdl, struct sdaddr_v6 *src)
{
        while (sdl->tag != NULL) {
                if (bsearch(src, sdl->v6.addrs, sdl->v6.naddrs,
                    sizeof(struct sdentry_v6), match_addr_v6) != NULL)
                        return (1);
                sdl++;
        }
        return (0);
}

/*
 * Given an address and address family
 * returns 1 if address is on a blacklist, else 0.
 */
int
sdl_check(struct sdlist *head, int af, void *src)
{
        if (head == NULL)
                return (0);

        switch (af) {
        case AF_INET:
                return (sdl_check_v4(head, src));
        case AF_INET6:
                return (sdl_check_v6(head, src));
        default:
                return (0);
        }
}

static void
sdl_free(struct sdlist *sdl)
{
        free(sdl->tag);
        free(sdl->string);
        free(sdl->v4.addrs);
        free(sdl->v6.addrs);
        sdl_clear(sdl);
}

static void
sdl_clear(struct sdlist *sdl)
{
        sdl->tag = NULL;
        sdl->string = NULL;
        sdl->v4.addrs = NULL;
        sdl->v4.naddrs = 0;
        sdl->v6.addrs = NULL;
        sdl->v6.naddrs = 0;
}