From: wessels <>
Date: Fri, 17 Jul 1998 07:02:22 +0000 (+0000)
Subject: added initial CARP code
X-Git-Tag: SQUID_3_0_PRE1~3058
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=afd88fbedace1d0b77b33ecb03c8243f4bc1df0e;p=thirdparty%2Fsquid.git

added initial CARP code
---

diff --git a/src/cache_cf.cc b/src/cache_cf.cc
index 47ee8a45fb..215f303b40 100644
--- a/src/cache_cf.cc
+++ b/src/cache_cf.cc
@@ -1,6 +1,6 @@
 
 /*
- * $Id: cache_cf.cc,v 1.287 1998/07/16 02:39:59 wessels Exp $
+ * $Id: cache_cf.cc,v 1.288 1998/07/17 01:02:22 wessels Exp $
  *
  * DEBUG: section 3     Configuration File Parsing
  * AUTHOR: Harvest Derived
@@ -783,6 +783,13 @@ parse_peer(peer ** head)
 #endif
 	} else if (!strncasecmp(token, "no-netdb-exchange", 17)) {
 	    EBIT_SET(p->options, NEIGHBOR_NO_NETDB_EXCHANGE);
+#if USE_CARP
+	} else if (!strncasecmp(token, "carp-load-factor=", 17)) {
+	    if (p->type != PEER_PARENT)
+		debug(3,0)("parse_peer: Ignoring carp-load-factor for non-parent %s/%d\n", p->host, p->http_port);
+	    else 
+	        p->carp.load_factor = atof(token + 17);
+#endif
 	} else {
 	    debug(3, 0) ("parse_peer: token='%s'\n", token);
 	    self_destruct();
@@ -792,6 +799,16 @@ parse_peer(peer ** head)
 	p->weight = 1;
     p->icp_version = ICP_VERSION_CURRENT;
     p->tcp_up = PEER_TCP_MAGIC_COUNT;
+#if USE_CARP
+    if (p->carp.load_factor) {
+        /*
+         * calculate this peers hash for use in CARP
+         */
+        p->carp.hash = 0;
+        for (token = p->host; *token != 0;token++)
+            p->carp.hash += (p->carp.hash << 19) + *token;
+    }
+#endif
     cbdataAdd(p, MEM_NONE);
     while (*head != NULL)
 	head = &(*head)->next;
diff --git a/src/carp.cc b/src/carp.cc
new file mode 100644
index 0000000000..3b101652a0
--- /dev/null
+++ b/src/carp.cc
@@ -0,0 +1,108 @@
+/*
+ * $Id: carp.cc,v 1.1 1998/07/17 01:02:24 wessels Exp $
+ *
+ * DEBUG: section 44    Cache Array Routing Protocol
+ * AUTHOR: Eric Stern
+ *
+ * SQUID Internet Object Cache  http://squid.nlanr.net/Squid/
+ * --------------------------------------------------------
+ *  
+ *  Squid is the result of efforts by numerous individuals from the
+ *  Internet community.  Development is led by Duane Wessels of the
+ *  National Laboratory for Applied Network Research and funded by
+ *  the National Science Foundation.
+ *  
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *      
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *      
+ */     
+
+#include "squid.h"
+
+#if USE_CARP
+
+void
+carpInit(void)
+{
+    /* calculate load factors */
+    int K = 0;
+    float a = 0.0;
+    float X;
+    float Xn;
+    float n;
+    int k;
+    peer *p;
+    for (p = Config.peers; p; p = p->next) {
+	a += p->carp.load_factor;
+	K++;
+    }
+    if (a == 0.0) 
+	/* CARP load factors not configured */
+	return;
+    /*
+     * sum of carp-load-factor's for all cache_peer's in squid.conf
+     * must equal 1.0
+     */
+    assert(a == 1.0);
+    k = 1;
+    n = 0;
+    Xn = 0;
+    for (p = Config.peers; p; p = p->next) {
+	X = pow(K * p->carp.load_factor, 1 / K);
+	if (Xn == 0)
+	    Xn = X;
+	else
+	    Xn *= X;
+	p->carp.load_multiplier = ((K - k + 1) * (p->carp.load_factor - n)) / Xn
+	    ;
+	k++;
+	n = p->carp.load_factor;
+    }
+}
+
+peer *
+carpSelectParent(request_t * request)
+{
+    const char *c;
+    peer *p = NULL;
+    peer *tp;
+    unsigned long url_hash = 0;
+    unsigned long combined_hash;
+    unsigned long high_score = 0;
+    const char *url = urlCanonical(request);
+    /* calculate url hash */
+    debug(44, 2) ("carpSelectParent: CARP Calculating hash for %s\n", url);
+    for (c = url; *c != 0; c++)
+	url_hash += (url_hash << 19) + *c;
+    /* select peer */
+    for (tp = Config.peers; tp; tp = tp->next) {
+	if (p->carp.load_factor == 0.0)
+		continue;
+	assert(p->type == PEER_PARENT);
+	combined_hash = (url_hash ^ tp->carp.hash);
+	combined_hash += combined_hash * 0x62531965;
+	combined_hash = combined_hash << 21;
+	combined_hash = combined_hash * tp->carp.load_multiplier;
+	debug(44, 3) ("carpSelectParent: %s combined_hash %d\n",
+		tp->host, combined_hash);
+	if ((combined_hash > high_score) && neighborUp(tp)) {
+	    p = tp;
+	    high_score = combined_hash;
+	}
+    }
+    if (p)
+        debug(44, 3) ("carpSelectParent: selected CARP %s\n", p->host);
+    return p;
+}
+#endif
diff --git a/src/enums.h b/src/enums.h
index f73ca0c109..4c20a44652 100644
--- a/src/enums.h
+++ b/src/enums.h
@@ -291,6 +291,9 @@ typedef enum {
 #if USE_CACHE_DIGESTS
     CACHE_DIGEST_HIT,
     NO_CACHE_DIGEST_DIRECT,
+#endif
+#if USE_CARP
+    CARP,
 #endif
     HIER_MAX
 } hier_code;
diff --git a/src/main.cc b/src/main.cc
index d97b2fdc7a..d624dbb958 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -1,6 +1,6 @@
 
 /*
- * $Id: main.cc,v 1.253 1998/07/06 19:18:30 wessels Exp $
+ * $Id: main.cc,v 1.254 1998/07/17 01:02:25 wessels Exp $
  *
  * DEBUG: section 1     Startup and Main Loop
  * AUTHOR: Harvest Derived
@@ -342,6 +342,9 @@ serverConnectionsOpen(void)
     netdbInit();
     asnInit();
     peerSelectInit();
+#if USE_CARP
+    carpInit();
+#endif
 }
 
 void
diff --git a/src/peer_select.cc b/src/peer_select.cc
index 5ac5752e20..d503ccf863 100644
--- a/src/peer_select.cc
+++ b/src/peer_select.cc
@@ -1,6 +1,6 @@
 
 /*
- * $Id: peer_select.cc,v 1.69 1998/07/16 22:22:50 wessels Exp $
+ * $Id: peer_select.cc,v 1.70 1998/07/17 01:02:26 wessels Exp $
  *
  * DEBUG: section 44    Peer Selection Algorithm
  * AUTHOR: Duane Wessels
@@ -51,6 +51,9 @@ const char *hier_strings[] =
 #if USE_CACHE_DIGESTS
     "CACHE_DIGEST_HIT",
     "NO_CACHE_DIGEST_DIRECT",
+#endif
+#if USE_CARP
+    "CARP",
 #endif
     "INVALID CODE"
 };
@@ -299,6 +302,12 @@ peerSelectFoo(ps_state * psstate)
 	hierarchyNote(&request->hier, code, &psstate->icp, p->host);
 	peerSelectCallback(psstate, p);
 	return;
+#endif
+#if USE_CARP
+    } else if ((p = carpSelectParent(request))) {
+        hierarchyNote(&request->hier, CARP, &psstate->icp, p->host);
+        peerSelectCallback(psstate, p);
+        return;
 #endif
     } else if ((p = netdbClosestParent(request))) {
 	request->hier.alg = PEER_SA_NETDB;
diff --git a/src/protos.h b/src/protos.h
index 1039884dc9..4a61c503ab 100644
--- a/src/protos.h
+++ b/src/protos.h
@@ -1010,6 +1010,12 @@ extern int internalStaticCheck(const char *urlpath);
 extern char *internalLocalUri(const char *dir, const char *name);
 extern char *internalRemoteUri(const char *, u_short, const char *, const char *);
 
+#if USE_CARP
+extern void carpInit(void);
+extern peer * carpSelectParent(request_t *);
+#endif
+
+
 /*
  * prototypes for system functions missing from system includes
  */
diff --git a/src/structs.h b/src/structs.h
index f9e98b05f4..a3b4eb966c 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -935,6 +935,13 @@ struct _peer {
     int rr_count;
     peer *next;
     int test_fd;
+#if USE_CARP
+    struct {
+	unsigned long hash;
+	unsigned long load_multiplier;
+	float load_factor;
+    } carp;
+#endif
 };
 
 struct _net_db_name {