/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of either:
*
* a) The GNU Lesser General Public License as published by the Free
* Software Foundation; either version 2.1, or (at your option) any
* later version,
*
* OR
*
* b) The two-clause BSD license.
*
* These licenses can be found with the distribution in the file LICENSES
*/
#include "spf_alt/spf_sys_config.h"
#ifdef STDC_HEADERS
# include <stdio.h> /* stdin / stdout */
# include <stdlib.h> /* malloc / free */
#endif
#ifdef HAVE_STRING_H
# include <string.h> /* strstr / strdup */
#else
# ifdef HAVE_STRINGS_H
# include <strings.h> /* strstr / strdup */
# endif
#endif
#ifdef HAVE_MEMORY_H
#include <memory.h>
#endif
#if TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# if HAVE_SYS_TIME_H
# include <sys/time.h>
# else
# include <time.h>
# endif
#endif
#ifdef HAVE_NETDB_H
# include <netdb.h>
#endif
#include "spf_alt/spf.h"
#include "spf_alt/spf_dns.h"
#include "spf_alt/spf_internal.h"
#include "spf_alt/spf_dns_internal.h"
#include "spf_alt/spf_dns_cache.h"
/*
* this is really little more than a proof-of-concept cache.
*
* The cache size is fixed and uses the CRC-32 function as a hash
* generator. Little is done about hash collisions, no alternate hash
* functions, no buckets, no linked lists, etc. There is a small
* reclaim list and if you add multiple DNS cache layers of different
* sizes you get slightly different hash functions. (The CRC-32
* function was chosen because I had a copy handy, it is pretty fast,
* and single bit changes are guarenteed to give a different hash.
* So, mx1.foo.com and mx2.foo.com will not collide)
*/
typedef struct
{
int debug;
SPF_dns_rr_t **cache;
int cache_size;
int hash_mask;
int max_hash_len;
SPF_dns_rr_t **reclaim;
int reclaim_size;
int reclaim_mask;
int hit;
int miss;
time_t min_ttl;
time_t err_ttl;
time_t txt_ttl;
time_t rdns_ttl;
int conserve_cache;
SPF_dns_rr_t nxdomain;
} SPF_dns_cache_config_t;
/* FXIME this isn't used. shouldn't we use c_results anyway? */
typedef struct
{
int hash;
SPF_id_t spfid;
SPF_id_t spfid_optimized;
time_t opt_utc_ttl;
SPF_id_t exp_id;
} SPF_dns_cache_data_t;
static inline SPF_dns_cache_config_t *SPF_voidp2spfhook( void *hook )
{ return (SPF_dns_cache_config_t *)hook; }
static inline void *SPF_spfhook2voidp( SPF_dns_cache_config_t *spfhook )
{ return (void *)spfhook; }
/*
** calculate CRC-32 stuff.
*/
/*
* COPYRIGHT (C) 1986 Gary S. Brown. You may use this program, or
* code or tables extracted from it, as desired without restriction.
*
* First, the polynomial itself and its table of feedback terms. The
* polynomial is
* X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0
*
* Note that we take it "backwards" and put the highest-order term in
* the lowest-order bit. The X^32 term is "implied"; the LSB is the
* X^31 term, etc. The X^0 term (usually shown as "+1") results in
* the MSB being 1
*
* Note that the usual hardware shift register implementation, which
* is what we're using (we're merely optimizing it by doing eight-bit
* chunks at a time) shifts bits into the lowest-order term. In our
* implementation, that means shifting towards the right. Why do we
* do it this way? Because the calculated CRC must be transmitted in
* order from highest-order term to lowest-order term. UARTs transmit
* characters in order from LSB to MSB. By storing the CRC this way
* we hand it to the UART in the order low-byte to high-byte; the UART
* sends each low-bit to hight-bit; and the result is transmission bit
* by bit from highest- to lowest-order term without requiring any bit
* shuffling on our part. Reception works similarly
*
* The feedback terms table consists of 256, 32-bit entries. Notes
*
* The table can be generated at runtime if desired; code to do so
* is shown later. It might not be obvious, but the feedback
* terms simply represent the results of eight shift/xor opera
* tions for all combinations of data and CRC register values
*
* The values must be right-shifted by eight bits by the "updcrc
* logic; the shift must be unsigned (bring in zeroes). On some
* hardware you could probably optimize the shift in assembler by
* using byte-swap instructions
* polynomial $edb88320
*/
const unsigned int crc_32_tab[256] = {
0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
0x2d02ef8dL
};
inline static int crc32str(unsigned int accum, const char *str, int max_hash_len )
{
for( ; *str != '\0' && max_hash_len > 0; str++ )
{
if ( *str == '.' )
continue;
accum = crc_32_tab[ (unsigned char)accum ^ (unsigned char)*str ]
^ (unsigned char)(accum >> 8);
max_hash_len--;
}
return(accum);
}
#define hash(h,s,a) (crc32str(a,s,h->max_hash_len) & (h->hash_mask))
static SPF_dns_rr_t *SPF_dns_lookup_cache( SPF_dns_config_t spfdcid, const char *domain, ns_type rr_type, int should_cache )
{
SPF_dns_iconfig_t *spfdic = SPF_dcid2spfdic( spfdcid );
SPF_dns_cache_config_t *spfhook = SPF_voidp2spfhook( spfdic->hook );
SPF_dns_rr_t *cached_rr, *reclaimed_rr, *fetched_rr;
int h, hr;
time_t t = 0;
char *p;
/* see if the RR is in the cache */
h = hash( spfhook, domain, spfhook->hash_mask + rr_type );
cached_rr = spfhook->cache[ h ];
if ( cached_rr
&& cached_rr->rr_type == rr_type
&& strcmp( cached_rr->domain, domain ) == 0
&& cached_rr->utc_ttl >= (t = time( NULL )))
{
spfhook->hit++;
if ( spfhook->debug > 1 )
SPF_debugf( "hit! %d/%d h: %d should_cache: %d%s",
spfhook->hit, spfhook->miss, h,
should_cache, cached_rr == NULL ? " cold" : ""
);
return cached_rr;
}
/* see if the RR is in the reclaim pool */
hr = h & spfhook->reclaim_mask;
reclaimed_rr = spfhook->reclaim[ hr ];
if ( reclaimed_rr
&& reclaimed_rr->rr_type == rr_type
&& strcmp( reclaimed_rr->domain, domain ) == 0
&& reclaimed_rr->utc_ttl >= (t ? t : (t = time( NULL ))))
{
spfhook->hit++;
if ( spfhook->debug > 1 )
SPF_debugf( "hit! %d/%d h: %d should_cache: %d%s reclaimed",
spfhook->hit, spfhook->miss, h,
should_cache, cached_rr == NULL ? " cold" : ""
);
spfhook->cache[ h ] = reclaimed_rr;
spfhook->reclaim[ hr ] = cached_rr;
return reclaimed_rr;
}
spfhook->miss++;
if ( spfhook->debug > 1 )
SPF_debugf( "miss... %d/%d h: %d should_cache: %d%s",
spfhook->hit, spfhook->miss, h,
should_cache, cached_rr == NULL ? " cold" : ""
);
if ( spfdic->layer_below )
fetched_rr = SPF_dcid2spfdic( spfdic->layer_below )->lookup( spfdic->layer_below, domain, rr_type, should_cache );
else
return &spfhook->nxdomain;
if ( spfhook->conserve_cache && !should_cache )
return fetched_rr;
/* try to stash away the cached RR onto the reclaim pool */
if ( cached_rr && cached_rr->utc_ttl > (t ? t : (t = time( NULL ))))
{
if ( reclaimed_rr == NULL )
reclaimed_rr = SPF_dns_create_rr();
if ( reclaimed_rr )
{
if ( SPF_dns_copy_rr( reclaimed_rr, cached_rr ) == SPF_E_SUCCESS )
spfhook->reclaim[ hr ] = reclaimed_rr;
else
{
SPF_dns_destroy_rr( reclaimed_rr );
reclaimed_rr = NULL;
}
}
}
/* try to store the fetched RR into the cache */
if ( cached_rr == NULL )
cached_rr = SPF_dns_create_rr();
if ( cached_rr == NULL )
return fetched_rr;
if ( SPF_dns_copy_rr( cached_rr, fetched_rr ) != SPF_E_SUCCESS )
{
SPF_dns_destroy_rr( cached_rr );
return fetched_rr;
}
/* make sure the RR has enough data to be useful for caching */
if ( cached_rr->rr_type == ns_t_any )
{
cached_rr->rr_type = rr_type;
if ( cached_rr->domain ) cached_rr->domain[0] = '\0';
}
if ( cached_rr->domain == NULL || cached_rr->domain[0] != '\0' )
{
char *new_domain;
size_t new_len = strlen( domain ) + 1;
if ( cached_rr->domain_buf_len < new_len )
{
new_domain = realloc( cached_rr->domain, new_len );
if ( new_domain == NULL )
{
SPF_dns_destroy_rr( cached_rr );
spfhook->cache[ h ] = NULL;
return fetched_rr;
}
cached_rr->domain = new_domain;
cached_rr->domain_buf_len = new_len;
}
strcpy( cached_rr->domain, domain );
}
/* set up the ttl values */
if ( cached_rr->ttl < spfhook->min_ttl )
cached_rr->ttl = spfhook->min_ttl;
if ( cached_rr->ttl < spfhook->txt_ttl
&& cached_rr->rr_type == ns_t_txt )
cached_rr->ttl = spfhook->txt_ttl;
if ( cached_rr->ttl < spfhook->err_ttl
&& cached_rr->herrno != NETDB_SUCCESS )
cached_rr->ttl = spfhook->err_ttl;
if ( cached_rr->ttl < spfhook->rdns_ttl )
{
p = strstr( cached_rr->domain, ".arpa" );
if ( p && p[ sizeof( ".arpa" )-1 ] == '\0' )
cached_rr->ttl = spfhook->rdns_ttl;
}
if ( t == 0 ) t = time( NULL );
cached_rr->utc_ttl = cached_rr->ttl + t;
spfhook->cache[ h ] = cached_rr;
return cached_rr;
}
SPF_dns_config_t SPF_dns_create_config_cache( SPF_dns_config_t layer_below, int cache_bits, int debug )
{
SPF_dns_iconfig_t *spfdic;
SPF_dns_cache_config_t *spfhook;
if ( layer_below == NULL )
SPF_error( "layer_below is NULL." );
if ( cache_bits < 1 || cache_bits > 16 )
SPF_error( "cache bits out of range (1..16)." );
spfdic = malloc( sizeof( *spfdic ) );
if ( spfdic == NULL )
return NULL;
spfdic->hook = malloc( sizeof( SPF_dns_cache_config_t ) );
if ( spfdic->hook == NULL )
{
free( spfdic );
return NULL;
}
spfdic->destroy = SPF_dns_destroy_config_cache;
spfdic->lookup = SPF_dns_lookup_cache;
#if 0
/* FIXME need to do more than just cache DNS records */
spfdic->get_spf = SPF_dns_get_spf_cache;
spfdic->get_exp = SPF_dns_get_exp_cache;
#else
spfdic->get_spf = NULL;
spfdic->get_exp = NULL;
spfdic->add_cache = NULL;
#endif
spfdic->layer_below = layer_below;
spfdic->name = "cache";
spfhook = SPF_voidp2spfhook( spfdic->hook );
spfhook->debug = debug;
spfhook->cache_size = 1 << cache_bits;
spfhook->hash_mask = spfhook->cache_size - 1;
spfhook->max_hash_len = cache_bits > 4 ? cache_bits * 2 : 8;
spfhook->reclaim_size = 1 << (cache_bits - 3); /* 8:1 overloading */
if ( spfhook->reclaim_size < 1 ) spfhook->reclaim_size = 1;
spfhook->reclaim_mask = spfhook->reclaim_size - 1;
spfhook->cache = calloc( spfhook->cache_size, sizeof( *spfhook->cache ) );
spfhook->reclaim = calloc( spfhook->reclaim_size, sizeof( *spfhook->reclaim ) );
spfhook->hit = 0;
spfhook->miss = 0;
spfhook->min_ttl = 30;
spfhook->err_ttl = 30*60;
spfhook->txt_ttl = 30*60;
spfhook->rdns_ttl = 30*60;
spfhook->conserve_cache = cache_bits < 12;
if ( spfhook->cache == NULL )
{
free( spfdic );
return NULL;
}
spfhook->nxdomain = SPF_dns_nxdomain;
spfhook->nxdomain.source = SPF_spfdic2dcid( spfdic );
return SPF_spfdic2dcid( spfdic );
}
void SPF_dns_reset_config_cache( SPF_dns_config_t spfdcid )
{
SPF_dns_iconfig_t *spfdic = SPF_dcid2spfdic( spfdcid );
SPF_dns_cache_config_t *spfhook;
int i;
if ( spfdcid == NULL )
SPF_error( "spfdcid is NULL" );
spfhook = SPF_voidp2spfhook( spfdic->hook );
if ( spfhook == NULL )
SPF_error( "spfdcid.hook is NULL" );
if ( spfhook->cache == NULL )
SPF_error( "spfdcid.hook->cache is NULL" );
if ( spfhook->reclaim == NULL )
SPF_error( "spfdcid.hook->reclaim is NULL" );
for( i = 0; i < spfhook->cache_size; i++ )
{
if ( spfhook->cache[i] )
SPF_dns_reset_rr( spfhook->cache[i] );
}
for( i = 0; i < spfhook->reclaim_size; i++ )
{
if ( spfhook->reclaim[i] )
SPF_dns_reset_rr( spfhook->reclaim[i] );
}
}
void SPF_dns_set_ttl_cache( SPF_dns_config_t spfdcid, time_t min_ttl,
time_t err_ttl, time_t txt_ttl,
time_t rdns_ttl )
{
SPF_dns_iconfig_t *spfdic = SPF_dcid2spfdic( spfdcid );
SPF_dns_cache_config_t *spfhook;
if ( spfdcid == NULL )
SPF_error( "spfdcid is NULL" );
spfhook = SPF_voidp2spfhook( spfdic->hook );
spfhook->min_ttl = min_ttl;
spfhook->err_ttl = err_ttl;
spfhook->txt_ttl = txt_ttl;
spfhook->rdns_ttl = rdns_ttl;
}
void SPF_dns_set_conserve_cache( SPF_dns_config_t spfdcid, int conserve_cache )
{
SPF_dns_iconfig_t *spfdic = SPF_dcid2spfdic( spfdcid );
SPF_dns_cache_config_t *spfhook;
if ( spfdcid == NULL )
SPF_error( "spfdcid is NULL" );
spfhook = SPF_voidp2spfhook( spfdic->hook );
spfhook->conserve_cache = conserve_cache;
}
void SPF_dns_destroy_config_cache( SPF_dns_config_t spfdcid )
{
SPF_dns_iconfig_t *spfdic = SPF_dcid2spfdic( spfdcid );
SPF_dns_cache_config_t *spfhook;
int i;
if ( spfdcid == NULL )
SPF_error( "spfdcid is NULL" );
spfhook = SPF_voidp2spfhook( spfdic->hook );
if ( spfhook )
{
for( i = 0; i < spfhook->cache_size; i++ )
{
if ( spfhook->cache[i] )
SPF_dns_destroy_rr( spfhook->cache[i] );
}
if ( spfhook->cache ) free( spfhook->cache );
for( i = 0; i < spfhook->reclaim_size; i++ )
{
if ( spfhook->reclaim[i] )
SPF_dns_destroy_rr( spfhook->reclaim[i] );
}
if ( spfhook->reclaim ) free( spfhook->reclaim );
free( spfhook );
}
free( spfdic );
}
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