INN commit: trunk (6 files)
INN Commit
Russ_Allbery at isc.org
Mon Mar 24 09:16:04 UTC 2008
Date: Monday, March 24, 2008 @ 02:16:03
Author: iulius
Revision: 7718
Implementation of the Diablo hashfeed algorithm. It allows
to distribute the messages among several peers (new Q flag
for newsfeeds).
Thanks to Miquel van Smoorenburg for this implementation in INN.
Also fix inncheck after commit 7713 for the legacy Diablo
quickhash (which uses the Q flag too).
Modified:
trunk/doc/pod/newsfeeds.pod
trunk/innd/art.c
trunk/innd/innd.h
trunk/innd/newsfeeds.c
trunk/innd/site.c
trunk/scripts/inncheck.in
-----------------------+
doc/pod/newsfeeds.pod | 47 ++++++++++++++++--------
innd/art.c | 92 +++++++++++++++++++++++++++++++++++++++---------
innd/innd.h | 19 ++++++---
innd/newsfeeds.c | 41 ++++++++++++++++-----
innd/site.c | 11 +++--
scripts/inncheck.in | 1
6 files changed, 159 insertions(+), 52 deletions(-)
Modified: doc/pod/newsfeeds.pod
===================================================================
--- doc/pod/newsfeeds.pod 2008-03-23 17:59:00 UTC (rev 7717)
+++ doc/pod/newsfeeds.pod 2008-03-24 09:16:03 UTC (rev 7718)
@@ -386,31 +386,48 @@
=item B<Q> I<hashfeed>
-Specifies the I<hashfeed> value for this site. The Message-ID of the
-article is hashed using a quick (but dirty) hash method (31-bits sum
-of the value of all characters). The I<hashfeed> value must be given
-as C<value/mod> or as C<start-end/mod>. If the Message-ID hash modulus
-C<mod> plus one equals C<value> or is between C<start> and C<end>,
-the article will be fed to this site. All these numbers must be integers.
+Specifies the I<hashfeed> match expression for this site. It must be in
+the form C<value/mod> or C<start-end/mod>. The Message-ID of the article
+is hashed using MD5, which results in a 128-bit hash. The lowest
+S<32 bits> are then taken by default as the hashfeed value (which is an
+integer). If the hashfeed value modulus C<mod> plus one equals C<value> or
+is between C<start> and C<end>, the article will be fed to this site. All
+these numbers must be integers.
+It is a deterministic way to control the flow of articles and to split a feed.
For instance:
- Q1/2 Feeds about 50% of the messages to this site.
- Q2/2 Feeds the other 50% of the messages.
+ Q1/2 Feeds about 50% of all articles to this site.
+ Q2/2 Feeds the other 50% of all articles.
Another example with three sites:
- Q1-3/10 Feeds about 30% of the messages.
- Q4-5/10 Feeds about 20% of the messages.
- Q6-10/10 Feeds about 50% of the messages.
+ Q1-3/10 Feeds about 30% of all articles.
+ Q4-5/10 Feeds about 20% of all articles.
+ Q6-10/10 Feeds about 50% of all articles.
If this flag is specified multiple times, the contents will be
-logically C<OR>ed together (just one matched flag is needed).
+logically C<OR>ed together (just one match is needed).
-The algorithm is compatible with the legacy Quickhash used by Diablo.
-Please note that the distribution of the messages is not perfect with
-this algorithm.
+You can use an extended syntax of the form C<value/mod_offset> or
+C<start-end/mod_offset>. As MD5 generates a 128-bit return value,
+it is possible to specify from which byte-offset the 32-bit integer
+used by hashfeed starts. The default value for C<offset> is C<_0>
+and thirteen overlapping values from C<_0> to C<_12> can be used.
+Only up to four totally independent values exist: C<_0>, C<_4>,
+C<_8> and C<_12>.
+Therefore, it allows to a generate a second level of deterministic
+distribution. Indeed, if a news server is fed C<Q1/2>, it can go on
+splitting thanks to C<Q1-3/9_4> for instance.
+
+The algorithm is compatible with the one used by S<Diablo 5.1> and up.
+If you want to use the legacy quickhashing method used by Diablo
+before 5.1, you can put an C<@> sign just after the B<Q> flag (for
+instance C<Q at 1-3/10>, but the distribution of the messages is not
+perfect with this legacy method whose use is discouraged and for
+which offsets cannot be used).
+
=item B<S> I<size>
If the amount of data queued for the site gets to be larger than I<size>
Modified: innd/art.c
===================================================================
--- innd/art.c 2008-03-23 17:59:00 UTC (rev 7717)
+++ innd/art.c 2008-03-24 09:16:03 UTC (rev 7718)
@@ -8,10 +8,11 @@
#include <sys/uio.h>
#include "inn/innconf.h"
+#include "inn/md5.h"
+#include "inn/ov.h"
+#include "inn/storage.h"
#include "inn/wire.h"
#include "innd.h"
-#include "inn/ov.h"
-#include "inn/storage.h"
typedef struct iovec IOVEC;
@@ -1538,23 +1539,81 @@
}
/*
-** Return true if an element of the QHASHLIST matches the
-** quickhash of the Message-ID.
+** Even though we have already calculated the Message-ID MD5sum,
+** we have to do it again since unfortunately HashMessageID()
+** lowercases the Message-ID first. We also need to remain
+** compatible with Diablo's hashfeed.
*/
-static bool
-QHashMatch(QHASHLIST *qh, char *MessageID)
+static unsigned int
+HashFeedMD5(char *MessageID, unsigned int offset)
{
- unsigned char *p = (unsigned char *)MessageID;
- int h = 0;
+ static char LastMessageID[128];
+ static char *LastMessageIDPtr;
+ static struct md5_context context;
+ unsigned int ret;
+ if (offset > 12)
+ return 0;
+
+ /* Some light caching. */
+ if (MessageID != LastMessageIDPtr ||
+ strcmp(MessageID, LastMessageID) != 0) {
+ md5_init(&context);
+ md5_update(&context, (unsigned char *)MessageID, strlen(MessageID));
+ md5_final(&context);
+ LastMessageIDPtr = MessageID;
+ strncpy(LastMessageID, MessageID, sizeof(LastMessageID) - 1);
+ LastMessageID[sizeof(LastMessageID) - 1] = 0;
+ }
+
+ memcpy(&ret, &context.digest[12 - offset], 4);
+
+ return ntohl(ret);
+}
+
+/*
+** Old-style Diablo (< 5.1) quickhash.
+*/
+static unsigned int
+HashFeedQH(char *MessageID, unsigned int *tmp)
+{
+ unsigned char *p;
+ int n;
+
+ if (*tmp != (unsigned int)-1)
+ return *tmp;
+
+ p = (unsigned char *)MessageID;
+ n = 0;
while (*p)
- h += *p++;
+ n += *p++;
+ *tmp = (unsigned int)n;
- while (qh) {
- if ((h % qh->mod + 1) >= qh->begin &&
- (h % qh->mod + 1) <= qh->end)
- return true;
- qh = qh->next;
+ return *tmp;
+}
+
+/*
+** Return true if an element of the HASHFEEDLIST matches
+** the hash of the Message-ID.
+*/
+static bool
+HashFeedMatch(HASHFEEDLIST *hf, char *MessageID)
+{
+ unsigned int qh = (unsigned int)-1;
+ unsigned int h;
+
+ while (hf) {
+ if (hf->type == HASHFEED_MD5)
+ h = HashFeedMD5(MessageID, hf->offset);
+ else if (hf->type == HASHFEED_QH)
+ h = HashFeedQH(MessageID, &qh);
+ else
+ continue;
+
+ if ((h % hf->mod + 1) >= hf->begin &&
+ (h % hf->mod + 1) <= hf->end)
+ return true;
+ hf = hf->next;
}
return false;
@@ -1633,8 +1692,9 @@
* cross-posting. */
continue;
- if (sp->QHashList && !QHashMatch(sp->QHashList, HDR(HDR__MESSAGE_ID)))
- /* Quickhash doesn't match. */
+ if (sp->HashFeedList
+ && !HashFeedMatch(sp->HashFeedList, HDR(HDR__MESSAGE_ID)))
+ /* Hashfeed doesn't match. */
continue;
if (list && *list != NULL && sp->Distributions &&
Modified: innd/innd.h
===================================================================
--- innd/innd.h 2008-03-23 17:59:00 UTC (rev 7717)
+++ innd/innd.h 2008-03-24 09:16:03 UTC (rev 7718)
@@ -401,13 +401,18 @@
/*
** Diablo-style hashed feeds or hashfeeds.
*/
-typedef struct _QHASHLIST {
- int begin;
- int end;
- int mod;
- struct _QHASHLIST *next;
-} QHASHLIST;
+#define HASHFEED_QH 1
+#define HASHFEED_MD5 2
+typedef struct _HASHFEEDLIST {
+ int type;
+ unsigned int begin;
+ unsigned int end;
+ unsigned int mod;
+ unsigned int offset;
+ struct _HASHFEEDLIST *next;
+} HASHFEEDLIST;
+
/*
** A site may reject something in its subscription list if it has
** too many hops, or a bad distribution.
@@ -460,7 +465,7 @@
struct buffer Buffer;
bool Buffered;
char ** Originator;
- QHASHLIST * QHashList;
+ HASHFEEDLIST * HashFeedList;
int Next;
int Prev;
} SITE;
Modified: innd/newsfeeds.c
===================================================================
--- innd/newsfeeds.c 2008-03-23 17:59:00 UTC (rev 7717)
+++ innd/newsfeeds.c 2008-03-24 09:16:03 UTC (rev 7718)
@@ -448,7 +448,7 @@
int isp;
SITE *nsp;
struct buffer b;
- QHASHLIST *qh;
+ HASHFEEDLIST *hf;
b = sp->Buffer;
*sp = SITEnull;
@@ -468,7 +468,7 @@
sp->NeedOverviewCreation = false;
sp->FeedwithoutOriginator = false;
sp->DropFiltered = false;
- sp->QHashList = NULL;
+ sp->HashFeedList = NULL;
/* Nip off the first field, the site name. */
if ((f2 = strchr(Entry, NF_FIELD_SEP)) == NULL)
@@ -601,16 +601,37 @@
sp->Nice = atoi(p);
break;
case 'Q':
- qh = xmalloc(sizeof(QHASHLIST));
+ hf = xmalloc(sizeof(HASHFEEDLIST));
p++;
- if (sscanf(p, "%d/%d", &qh->begin, &qh->mod) == 2) {
- qh->end = qh->begin;
- } else if (sscanf(p, "%d-%d/%d", &qh->begin, &qh->end, &qh->mod) != 3) {
- free(qh);
- return "hash for Q not in x/z or x-y/z format";
+ /* Check whether it is a quickhash or a MD5 hashfeed. */
+ if (*p == '@') {
+ p++;
+ hf->type = HASHFEED_QH;
+ } else {
+ hf->type = HASHFEED_MD5;
}
- qh->next = sp->QHashList;
- sp->QHashList = qh;
+ /* Check the presence of a starting byte-offset for hashfeed. */
+ if ((u = strchr(p, '_')) != NULL) {
+ if (sscanf(u + 1, "%u", &hf->offset) != 1 || hf->offset > 12) {
+ free(hf);
+ return "invalid hash offset for Q param in field 3";
+ }
+ } else {
+ hf->offset = 0;
+ }
+ if (sscanf(p, "%u/%u", &hf->begin, &hf->mod) == 2) {
+ hf->end = hf->begin;
+ } else if (sscanf(p, "%u-%u/%u", &hf->begin, &hf->end,
+ &hf->mod) != 3) {
+ free(hf);
+ return "hash not in x/z or x-y/z format for Q param in field 3";
+ }
+ if (hf->begin > hf->end || hf->end > hf->mod) {
+ free(hf);
+ return "incorrect hash values for Q param in field 3";
+ }
+ hf->next = sp->HashFeedList;
+ sp->HashFeedList = hf;
break;
case 'S':
if (*++p && CTYPE(isdigit, *p))
Modified: innd/site.c
===================================================================
--- innd/site.c 2008-03-23 17:59:00 UTC (rev 7717)
+++ innd/site.c 2008-03-24 09:16:03 UTC (rev 7718)
@@ -1005,7 +1005,7 @@
SITEfree(SITE *sp)
{
SITE *s;
- QHASHLIST *qh, *qn;
+ HASHFEEDLIST *hf, *hn;
int new;
int i;
@@ -1060,9 +1060,12 @@
sp->FNLnames.data = NULL;
sp->FNLnames.size = 0;
}
- for (qh = sp->QHashList; qh; qh = qn) {
- qn = qh->next;
- free(qh);
+ if (sp->HashFeedList) {
+ for (hf = sp->HashFeedList; hf; hf = hn) {
+ hn = hf->next;
+ free(hf);
+ }
+ sp->HashFeedList = NULL;
}
/* If this site was a master, find a new one. */
Modified: scripts/inncheck.in
===================================================================
--- scripts/inncheck.in 2008-03-23 17:59:00 UTC (rev 7717)
+++ scripts/inncheck.in 2008-03-24 09:16:03 UTC (rev 7718)
@@ -360,6 +360,7 @@
'N', '^[mu]$',
'O', '^\S+$',
'P', '^\d+$',
+ 'Q', '^@?\d+(-\d+)?/\d+(_\d+)?$',
'S', '^\d+$',
'T', '^[cflmpx]$',
'U', '^\d+$',
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