INN commit: branches/2.4 (6 files)
INN Commit
Russ_Allbery at isc.org
Sun Apr 6 08:27:16 UTC 2008
Date: Sunday, April 6, 2008 @ 01:27:16
Author: iulius
Revision: 7730
Implementation of the Diablo quickhash and hashfeed algorithms.
It allows to distribute the messages among several peers (new Q flag
for newsfeeds).
Thanks to Miquel van Smoorenburg for this implementation in INN.
Modified:
branches/2.4/doc/pod/newsfeeds.pod
branches/2.4/innd/art.c
branches/2.4/innd/innd.h
branches/2.4/innd/newsfeeds.c
branches/2.4/innd/site.c
branches/2.4/scripts/inncheck.in
-----------------------+
doc/pod/newsfeeds.pod | 44 ++++++++++++++++++++++++
innd/art.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++
innd/innd.h | 17 +++++++++
innd/newsfeeds.c | 33 ++++++++++++++++++
innd/site.c | 8 ++++
scripts/inncheck.in | 1
6 files changed, 191 insertions(+)
Modified: doc/pod/newsfeeds.pod
===================================================================
--- doc/pod/newsfeeds.pod 2008-04-06 08:05:07 UTC (rev 7729)
+++ doc/pod/newsfeeds.pod 2008-04-06 08:27:16 UTC (rev 7730)
@@ -382,6 +382,50 @@
new process will run with. This flag can be used to raise the priority to
normal if you're using the I<nicekids> parameter in F<inn.conf>.
+=item B<Q> I<hashfeed>
+
+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 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 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 match is needed).
+
+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 2008-04-06 08:05:07 UTC (rev 7729)
+++ innd/art.c 2008-04-06 08:27:16 UTC (rev 7730)
@@ -9,6 +9,7 @@
#include "inn/innconf.h"
#include "inn/wire.h"
+#include "inn/md5.h"
#include "innd.h"
#include "ov.h"
#include "storage.h"
@@ -1553,6 +1554,88 @@
}
/*
+** 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 unsigned int
+HashFeedMD5(char *MessageID, unsigned int offset)
+{
+ 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)
+ n += *p++;
+ *tmp = (unsigned int)n;
+
+ 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;
+}
+
+/*
** Propagate an article to the sites have "expressed an interest."
*/
static void
@@ -1625,6 +1708,11 @@
* cross-posting. */
continue;
+ if (sp->HashFeedList &&
+ !HashFeedMatch(sp->HashFeedList, HDR(HDR__MESSAGE_ID)))
+ /* hashfeed doesn't match */
+ continue;
+
if (list && *list != NULL && sp->Distributions &&
!DISTwantany(sp->Distributions, list))
/* Not in the site's desired list of distributions. */
Modified: innd/innd.h
===================================================================
--- innd/innd.h 2008-04-06 08:05:07 UTC (rev 7729)
+++ innd/innd.h 2008-04-06 08:27:16 UTC (rev 7730)
@@ -407,6 +407,22 @@
/*
+** Diablo-style hashed feeds or hashfeeds.
+*/
+#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.
*/
@@ -458,6 +474,7 @@
struct buffer Buffer;
bool Buffered;
char ** Originator;
+ HASHFEEDLIST * HashFeedList;
int Next;
int Prev;
} SITE;
Modified: innd/newsfeeds.c
===================================================================
--- innd/newsfeeds.c 2008-04-06 08:05:07 UTC (rev 7729)
+++ innd/newsfeeds.c 2008-04-06 08:27:16 UTC (rev 7730)
@@ -448,6 +448,7 @@
int isp;
SITE *nsp;
struct buffer b;
+ HASHFEEDLIST *hf;
b = sp->Buffer;
*sp = SITEnull;
@@ -467,6 +468,7 @@
sp->NeedOverviewCreation = false;
sp->FeedwithoutOriginator = false;
sp->DropFiltered = false;
+ sp->HashFeedList = NULL;
/* Nip off the first field, the site name. */
if ((f2 = strchr(Entry, NF_FIELD_SEP)) == NULL)
@@ -603,6 +605,37 @@
if (*++p && CTYPE(isdigit, *p))
sp->Nice = atoi(p);
break;
+ case 'Q':
+ hf = xmalloc(sizeof(HASHFEEDLIST));
+ p++;
+ /* Check whether it is a quickhash or a MD5 hashfeed. */
+ if (*p == '@') {
+ p++;
+ hf->type = HASHFEED_QH;
+ } else
+ hf->type = HASHFEED_MD5;
+ /* 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))
sp->StartSpooling = atol(p);
Modified: innd/site.c
===================================================================
--- innd/site.c 2008-04-06 08:05:07 UTC (rev 7729)
+++ innd/site.c 2008-04-06 08:27:16 UTC (rev 7730)
@@ -997,6 +997,7 @@
SITEfree(SITE *sp)
{
SITE *s;
+ HASHFEEDLIST *hf, *hn;
int new;
int i;
@@ -1051,6 +1052,13 @@
sp->FNLnames.data = NULL;
sp->FNLnames.size = 0;
}
+ 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. */
if (sp->IsMaster) {
Modified: scripts/inncheck.in
===================================================================
--- scripts/inncheck.in 2008-04-06 08:05:07 UTC (rev 7729)
+++ scripts/inncheck.in 2008-04-06 08:27:16 UTC (rev 7730)
@@ -367,6 +367,7 @@
'N', '^[mu]$',
'O', '^\S+$',
'P', '^\d+$',
+ 'Q', '^@?\d+(-\d+)?/\d+(_\d+)?$',
'S', '^\d+$',
'T', '^[cflmpx]$',
'W', '^[befghmnpst*DGHNPOR]*$',
More information about the inn-committers
mailing list