/*
* $Id$
*
+ * This file contains the central state machine for pushing requests.
+ *
+ * We cannot just use direct calls because it is possible to kick a
+ * request back to the lookup stage (usually after a rewrite). The
+ * state engine also allows us to break the processing up into some
+ * logical chunks which improves readability a little bit.
+ *
+ * Since the states are rather nasty in detail, I have decided to embedd
+ * a dot(1) graph in the source code comments. So to see the big picture,
+ * extract the DOT lines and run though dot(1), for instance with the
+ * command:
+ * sed -n '/^DOT/s///p' cache_center.c | dot -Tps > /tmp/_.ps
+ *
+ */
+
+/*
+DOT digraph vcl_center {
+DOT page="8.2,11.7"
+DOT size="6.3,9.7"
+DOT margin="1.0"
+DOT start [
+DOT shape=hexagon
+DOT label="Start"
+DOT ]
+DOT start -> RECV
*/
#include <stdio.h>
return (1);
}
-void
-CNT_Session(struct worker *w, struct sess *sp)
+/*--------------------------------------------------------------------
+DOT subgraph cluster_deliver {
+DOT deliver [
+DOT shape=ellipse
+DOT label="Build & send header"
+DOT ]
+DOT DELIVER -> deliver [style=bold]
+DOT deliver2 [
+DOT shape=ellipse
+DOT label="Send object"
+DOT ]
+DOT deliver -> deliver2 [style=bold]
+DOT }
+DOT deliver2 -> DONE [style=bold]
+ */
+
+static void cnt_deliver(struct worker *w, struct sess *sp) { (void)w; (void)sp; INCOMPL(); }
+
+/*--------------------------------------------------------------------
+DOT DONE [
+DOT shape=hexagon
+DOT label="Request completed"
+DOT ]
+ */
+
+#if 0
+ if (http_GetHdr(sp->http, "Connection", &b) &&
+ !strcmp(b, "close")) {
+ vca_close_session(sp, "Connection header");
+ } else if (http_GetProto(sp->http, &b) &&
+ strcmp(b, "HTTP/1.1")) {
+ vca_close_session(sp, "not HTTP/1.1");
+#endif
+
+static void cnt_done(struct worker *w, struct sess *sp) { (void)w; (void)sp; INCOMPL(); }
+
+/*--------------------------------------------------------------------
+DOT subgraph cluster_error {
+DOT error [
+DOT shape=ellipse
+DOT label="Issue HTTP error"
+DOT ]
+DOT ERROR -> error
+DOT }
+DOT error -> DONE
+ */
+
+static void cnt_error(struct worker *w, struct sess *sp) { (void)w; (void)sp; INCOMPL(); }
+
+/*--------------------------------------------------------------------
+DOT subgraph cluster_fetch {
+DOT fetch [
+DOT shape=ellipse
+DOT label="find obj.ttl\nobj.cacheable"
+DOT ]
+DOT FETCH -> fetch [style=bold]
+DOT vcl_fetch [
+DOT shape=box
+DOT label="vcl_fetch()"
+DOT ]
+DOT fetch -> vcl_fetch [style=bold]
+DOT fetch_lookup [
+DOT shape=ellipse
+DOT label="obj.cacheable=false\nunbusy obj\ndiscard body\n"
+DOT ]
+DOT vcl_fetch -> fetch_lookup [label="lookup", style=dotted, weight=0]
+DOT fetch_pass [
+DOT shape=ellipse
+DOT label="obj.cacheable=false\nunbusy obj"
+DOT ]
+DOT vcl_fetch -> fetch_pass [label="pass"]
+DOT fetch_ipass [
+DOT shape=ellipse
+DOT label="obj.cacheable=true\nobj.pass=true\nunbusy obj"
+DOT ]
+DOT vcl_fetch -> fetch_ipass [label="insert_pass"]
+DOT fetch_insert [
+DOT shape=ellipse
+DOT label="rcv body\nobj.cacheable=true\nunbusy"
+DOT ]
+DOT vcl_fetch -> fetch_insert [label="insert", style=bold]
+DOT fetch_error [
+DOT shape=ellipse
+DOT label="disc body\nobj.cacheable=false\nunbusy"
+DOT ]
+DOT vcl_fetch -> fetch_error [label="error"]
+DOT }
+DOT fetch_lookup -> LOOKUP [style=dotted, weight=0]
+DOT fetch_pass -> PASSBODY
+DOT fetch_ipass -> PASSBODY
+DOT fetch_insert -> DELIVER [style=bold]
+DOT fetch_error -> ERROR
+ */
+
+static void cnt_fetch(struct worker *w, struct sess *sp) { (void)w; (void)sp; INCOMPL(); }
+
+/*--------------------------------------------------------------------
+DOT subgraph cluster_hit {
+DOT hit [
+DOT shape=box
+DOT label="vcl_hit()"
+DOT ]
+DOT HIT -> hit [style=bold]
+DOT hit2 [
+DOT shape=diamond
+DOT label="obj.pass ?"
+DOT ]
+DOT hit -> hit2 [label=deliver, style=bold]
+DOT hit_lookup [
+DOT shape=ellipse
+DOT label="unbusy"
+DOT ]
+DOT hit -> hit_lookup [label="lookup", style=dotted, weight=0]
+DOT hit_error [
+DOT shape=ellipse
+DOT label="unbusy"
+DOT ]
+DOT hit -> hit_error [label="error", weight=0]
+DOT hit_pass [
+DOT shape=ellipse
+DOT label="unbusy"
+DOT ]
+DOT hit -> hit_pass [label=pass]
+DOT hit2 -> hit_pass
+DOT }
+DOT hit_error -> ERROR
+DOT hit_pass -> PASS
+DOT hit_lookup -> LOOKUP [style=dotted, weight=0]
+DOT hit2 -> DELIVER [style=bold]
+ */
+
+static void cnt_hit(struct worker *w, struct sess *sp) { (void)w; (void)sp; INCOMPL(); }
+
+/*--------------------------------------------------------------------
+DOT subgraph cluster_lookup {
+DOT lookup [
+DOT shape=ellipse
+DOT label="find obj in cache"
+DOT ]
+DOT LOOKUP -> lookup [style=bold]
+DOT lookup2 [
+DOT shape=ellipse
+DOT label="Insert new busy object"
+DOT ]
+DOT lookup -> lookup2 [style=bold]
+DOT }
+DOT lookup -> HIT [label="hit", style=bold]
+DOT lookup2 -> MISS [label="miss", style=bold]
+ */
+
+static void cnt_lookup(struct worker *w, struct sess *sp) { (void)w; (void)sp; INCOMPL(); }
+
+/*--------------------------------------------------------------------
+DOT subgraph cluster_miss {
+DOT miss [
+DOT shape=box
+DOT label="vcl_miss()"
+DOT ]
+DOT MISS -> miss [style=bold]
+DOT miss_error [
+DOT shape=ellipse
+DOT label="obj.cacheable=false\nunbusy"
+DOT ]
+DOT miss -> miss_error [label="error"]
+DOT miss_pass [
+DOT shape=ellipse
+DOT label="obj.cacheable=false\nunbusy"
+DOT ]
+DOT miss -> miss_pass [label="pass"]
+DOT miss_lookup [
+DOT shape=ellipse
+DOT label="obj.cacheable=false\nunbusy"
+DOT ]
+DOT miss -> miss_lookup [label="lookup", style=dotted, weight=0]
+DOT miss_fetch [
+DOT shape=ellipse
+DOT label="fetch obj headers\nfrom backend"
+DOT ]
+DOT miss -> miss_fetch [label="fetch", style=bold]
+DOT }
+DOT miss_error -> ERROR
+DOT miss_pass -> PASS
+DOT miss_fetch -> FETCH [style=bold]
+DOT miss_lookup -> LOOKUP [style=dotted, weight=0]
+DOT
+ */
+
+static void cnt_miss(struct worker *w, struct sess *sp) { (void)w; (void)sp; INCOMPL(); }
+
+/*--------------------------------------------------------------------
+DOT subgraph cluster_pass {
+DOT pass [
+DOT shape=ellipse
+DOT label="send to bke\nrx bkehdr"
+DOT ]
+DOT PASS -> pass
+DOT }
+DOT pass -> PASSBODY
+ */
+
+static void cnt_pass(struct worker *w, struct sess *sp) { (void)w; (void)sp; INCOMPL(); }
+
+/*--------------------------------------------------------------------
+DOT subgraph cluster_passbody {
+DOT passbody [
+DOT shape=ellipse
+DOT label="send hdrs\npass body\n"
+DOT ]
+DOT PASSBODY -> passbody
+DOT }
+DOT passbody -> DONE
+ */
+
+static void cnt_passbody(struct worker *w, struct sess *sp) { (void)w; (void)sp; INCOMPL(); }
+
+/*--------------------------------------------------------------------
+DOT subgraph cluster_pipe {
+DOT pipe [
+DOT shape=ellipse
+DOT label="build&send hdr\npipe until close"
+DOT ]
+DOT PIPE -> pipe
+DOT }
+DOT pipe -> DONE
+ */
+
+static void cnt_pipe(struct worker *w, struct sess *sp) { (void)w; (void)sp; INCOMPL(); }
+
+/*--------------------------------------------------------------------
+DOT subgraph cluster_recv {
+DOT recv [
+DOT shape=box
+DOT label="vcl_recv()"
+DOT ]
+DOT RECV -> recv
+DOT recv_lookup [
+DOT shape=ellipse
+DOT label="discard any body"
+DOT ]
+DOT recv -> recv_lookup [label="lookup"]
+DOT recv_error [
+DOT shape=ellipse
+DOT label="discard any body"
+DOT ]
+DOT recv -> recv_error [label="error"]
+DOT }
+DOT recv -> PIPE [label="pipe"]
+DOT recv -> PASS [label="pass"]
+DOT recv_lookup -> LOOKUP
+DOT recv_error -> ERROR
+ */
+
+static void
+cnt_recv(struct worker *w, struct sess *sp)
{
int done;
- char *b;
-
- time(&sp->t0);
- AZ(pthread_mutex_lock(&sessmtx));
- sp->vcl = GetVCL();
- AZ(pthread_mutex_unlock(&sessmtx));
done = http_DissectRequest(sp->http, sp->fd);
if (done != 0) {
RES_Error(w, sp, done, NULL);
- goto out;
+ sp->step = STP_DONE;
+ return;
}
sp->backend = sp->vcl->backend[0];
+ /* XXX: Handle TRACE & OPTIONS of Max-Forwards = 0 */
+
+ /* XXX: determine if request comes with body */
+
VCL_recv_method(sp);
- for (done = 0; !done; ) {
- switch(sp->handling) {
- case VCL_RET_LOOKUP:
- done = LookupSession(w, sp);
- break;
- case VCL_RET_FETCH:
- done = FetchSession(w, sp);
- break;
- case VCL_RET_DELIVER:
- done = DeliverSession(w, sp);
- break;
- case VCL_RET_PIPE:
- PipeSession(w, sp);
- done = 1;
- break;
- case VCL_RET_PASS:
- PassSession(w, sp);
- done = 1;
- break;
- default:
- INCOMPL();
- }
+ switch(sp->handling) {
+ case VCL_RET_LOOKUP:
+ /* XXX: discard req body, if any */
+ sp->step = STP_LOOKUP;
+ return;
+ case VCL_RET_PIPE:
+ sp->step = STP_PIPE;
+ return;
+ case VCL_RET_PASS:
+ sp->step = STP_PASS;
+ return;
+ case VCL_RET_ERROR:
+ /* XXX: discard req body, if any */
+ sp->step = STP_ERROR;
+ return;
+ default:
+ INCOMPL();
}
- if (http_GetHdr(sp->http, "Connection", &b) &&
- !strcmp(b, "close")) {
- vca_close_session(sp, "Connection header");
- } else if (http_GetProto(sp->http, &b) &&
- strcmp(b, "HTTP/1.1")) {
- vca_close_session(sp, "not HTTP/1.1");
+}
+
+
+/*--------------------------------------------------------------------
+ * Central state engine dispatcher.
+ *
+ * We grab a VCL reference, and keeps kicking the session around until
+ * it has had enough.
+ *
+ */
+
+void
+CNT_Session(struct worker *w, struct sess *sp)
+{
+
+ time(&sp->t0);
+ AZ(pthread_mutex_lock(&sessmtx));
+ sp->vcl = GetVCL();
+ AZ(pthread_mutex_unlock(&sessmtx));
+
+ for (sp->step = STP_RECV; sp->step != STP_DONE; ) {
+ switch (sp->step) {
+#define STEP(l,u) case STP_##u: cnt_##l(w, sp); break;
+#include "steps.h"
+#undef STEP
+ default: INCOMPL();
+ }
}
-out:
AZ(pthread_mutex_lock(&sessmtx));
RelVCL(sp->vcl);
AZ(pthread_mutex_unlock(&sessmtx));
sp->vcl = NULL;
+
vca_return_session(sp);
}
+
+/*
+DOT }
+*/
projects / varnish / commitdiff