simple, functional interface to add additional balancer lb selection methods (f9c6b9cd) · Commits · CYBER - Cyber Security / TS 103 523 MSP / TLMSP / TLMSP Apache Httpd

CHANGES

+5 −0

Original line number	Diff line number	Diff line
		-- coding: utf-8 --
		Changes with Apache 2.3.0

		*) mod_proxy/mod_proxy_balancer: Provide a simple, functional
		interface to add additional balancer lb selection methods
		without requiring code changes to mod_proxy/mod_proxy_balancer;
		these can be implemented via sub-modules now. [Jim Jagielski]

		*) mod_cache: Fix incorrectly served 304 responses when expired cache
		entity is valid, but cache is unwritable and headers cannot be
		updated. [Colm MacCarthaigh <colm stdlib.net>]

modules/proxy/mod_proxy.c

+26 −13

Original line number	Diff line number	Diff line
		@@ -224,7 +224,8 @@ static const char set_worker_param(apr_pool_t p,
		return NULL;
		}

		static const char set_balancer_param(apr_pool_t p,
		static const char set_balancer_param(proxy_server_conf conf,
		apr_pool_t *p,
		proxy_balancer *balancer,
		const char *key,
		const char *val)
		@@ -272,13 +273,17 @@ static const char set_balancer_param(apr_pool_t p,
		balancer->max_attempts_set = 1;
		}
		else if (!strcasecmp(key, "lbmethod")) {
		/* Which LB scheduler method */
		if (!strcasecmp(val, "traffic"))
		balancer->lbmethod = lbmethod_traffic;
		else if (!strcasecmp(val, "requests"))
		balancer->lbmethod = lbmethod_requests;
		else
		return "lbmethod must be Traffic\|Requests";
		struct proxy_balancer_method *ent =
		(struct proxy_balancer_method *) conf->lbmethods->elts;
		int i;
		for (i = 0; i < conf->lbmethods->nelts; i++) {
		if (!strcasecmp(val, ent->name)) {
		balancer->lbmethod = ent;
		return NULL;
		}
		ent++;
		}
		return "unknown lbmethod";
		}
		else {
		return "unknown Balancer parameter";
		@@ -793,6 +798,7 @@ static void * create_proxy_config(apr_pool_t p, server_rec s)
		ps->allowed_connect_ports = apr_array_make(p, 10, sizeof(int));
		ps->workers = apr_array_make(p, 10, sizeof(proxy_worker));
		ps->balancers = apr_array_make(p, 10, sizeof(proxy_balancer));
		ps->lbmethods = apr_array_make(p, 10, sizeof(proxy_balancer_method));
		ps->forward = NULL;
		ps->reverse = NULL;
		ps->domain = NULL;
		@@ -815,6 +821,9 @@ static void * create_proxy_config(apr_pool_t p, server_rec s)
		ps->badopt = bad_error;
		ps->badopt_set = 0;
		ps->pool = p;

		proxy_run_load_lbmethods(ps);

		return ps;
		}

		@@ -832,6 +841,7 @@ static void * merge_proxy_config(apr_pool_t p, void basev, void *overridesv)
		ps->allowed_connect_ports = apr_array_append(p, base->allowed_connect_ports, overrides->allowed_connect_ports);
		ps->workers = apr_array_append(p, base->workers, overrides->workers);
		ps->balancers = apr_array_append(p, base->balancers, overrides->balancers);
		ps->lbmethods = apr_array_append(p, base->lbmethods, overrides->lbmethods);
		ps->forward = overrides->forward ? overrides->forward : base->forward;
		ps->reverse = overrides->reverse ? overrides->reverse : base->reverse;

		@@ -1021,7 +1031,7 @@ static const char *
		return apr_pstrcat(cmd->temp_pool, "ProxyPass ", err, NULL);
		}
		for (i = 0; i < arr->nelts; i++) {
		const char *err = set_balancer_param(cmd->pool, balancer, elts[i].key,
		const char *err = set_balancer_param(conf, cmd->pool, balancer, elts[i].key,
		elts[i].val);
		if (err)
		return apr_pstrcat(cmd->temp_pool, "ProxyPass ", err, NULL);
		@@ -1509,7 +1519,7 @@ static const char *
		if (worker)
		err = set_worker_param(cmd->pool, worker, word, val);
		else
		err = set_balancer_param(cmd->pool, balancer, word, val);
		err = set_balancer_param(conf, cmd->pool, balancer, word, val);

		if (err)
		return apr_pstrcat(cmd->temp_pool, "ProxySet ", err, " ", word, " ", name, NULL);
		@@ -1754,9 +1764,7 @@ static int proxy_status_hook(request_rec *r, int flags)
		ap_rprintf(r, "</td><td>%" APR_TIME_T_FMT "</td>",
		apr_time_sec(balancer->timeout));
		ap_rprintf(r, "<td>%s</td>\n",
		balancer->lbmethod == lbmethod_requests ? "Requests" :
		balancer->lbmethod == lbmethod_traffic ? "Traffic" :
		"Unknown");
		balancer->lbmethod->name);
		ap_rputs("</table>\n", r);
		ap_rputs("\n\n<table border=\"0\"><tr>"
		"<th>Sch</th><th>Host</th><th>Stat</th>"
		@@ -1917,6 +1925,7 @@ APR_HOOK_STRUCT(
		APR_HOOK_LINK(canon_handler)
		APR_HOOK_LINK(pre_request)
		APR_HOOK_LINK(post_request)
		APR_HOOK_LINK(load_lbmethods)
		APR_HOOK_LINK(request_status)
		)

		@@ -1942,6 +1951,10 @@ APR_IMPLEMENT_EXTERNAL_HOOK_RUN_FIRST(proxy, PROXY, int, post_request,
		request_rec *r,
		proxy_server_conf *conf),(worker,
		balancer,r,conf),DECLINED)
		APR_IMPLEMENT_EXTERNAL_HOOK_RUN_ALL(proxy, PROXY, int, load_lbmethods,
		(proxy_server_conf *conf),
		(conf),
		OK, DECLINED)
		APR_IMPLEMENT_OPTIONAL_HOOK_RUN_ALL(proxy, PROXY, int, fixups,
		(request_rec *r), (r),
		OK, DECLINED)

modules/proxy/mod_proxy.h

+21 −4

Original line number	Diff line number	Diff line
		@@ -120,6 +120,7 @@ struct noproxy_entry {
		typedef struct proxy_balancer proxy_balancer;
		typedef struct proxy_worker proxy_worker;
		typedef struct proxy_conn_pool proxy_conn_pool;
		typedef struct proxy_balancer_method proxy_balancer_method;

		typedef struct {
		apr_array_header_t *proxies;
		@@ -179,6 +180,7 @@ typedef struct {
		} proxy_status; /* Status display options */
		char proxy_status_set;
		apr_pool_t pool; / Pool used for allocating this struct */
		apr_array_header_t *lbmethods;
		} proxy_server_conf;


		@@ -257,6 +259,7 @@ typedef struct {
		apr_size_t elected; /* Number of times the worker was elected */
		char route[PROXY_WORKER_MAX_ROUTE_SIZ+1];
		char redirect[PROXY_WORKER_MAX_ROUTE_SIZ+1];
		void context; / general purpose storage */
		} proxy_worker_stat;

		/* Worker configuration */
		@@ -293,6 +296,7 @@ struct proxy_worker {
		#if APR_HAS_THREADS
		apr_thread_mutex_t mutex; / Thread lock for updating address cache */
		#endif
		void context; / general purpose storage */
		};

		struct proxy_balancer {
		@@ -303,10 +307,7 @@ struct proxy_balancer {
		apr_interval_time_t timeout; /* Timeout for waiting on free connection */
		int max_attempts; /* Number of attempts before failing */
		char max_attempts_set;
		enum {
		lbmethod_requests = 1,
		lbmethod_traffic = 2
		} lbmethod;
		proxy_balancer_method *lbmethod;

		/* XXX: Perhaps we will need the proc mutex too.
		* Altrough we are only using arithmetic operations
		@@ -316,6 +317,14 @@ struct proxy_balancer {
		#if APR_HAS_THREADS
		apr_thread_mutex_t mutex; / Thread lock for updating lb params */
		#endif
		void context; / general purpose storage */
		};

		struct proxy_balancer_method {
		const char name; / name of the load balancer method*/
		proxy_worker (finder)(proxy_balancer *balancer,
		request_rec *r);
		void context; / general purpose storage */
		};

		#if APR_HAS_THREADS
		@@ -365,6 +374,14 @@ APR_DECLARE_EXTERNAL_HOOK(proxy, PROXY, int, canon_handler, (request_rec *r,
		APR_DECLARE_EXTERNAL_HOOK(proxy, PROXY, int, create_req, (request_rec r, request_rec pr))
		APR_DECLARE_EXTERNAL_HOOK(proxy, PROXY, int, fixups, (request_rec *r))

		/*
		* Useful hook run within the create per-server phase which
		* adds the required lbmethod structs, so they exist at
		* configure time
		*/
		APR_DECLARE_EXTERNAL_HOOK(proxy, PROXY, int, load_lbmethods,
		(proxy_server_conf *conf))

		/**
		* pre request hook.
		* It will return the most suitable worker at the moment

modules/proxy/mod_proxy_balancer.c

+67 −39

Original line number	Diff line number	Diff line
		@@ -21,6 +21,7 @@
		#include "mod_proxy.h"
		#include "ap_mpm.h"
		#include "apr_version.h"
		#include "apr_hooks.h"

		module AP_MODULE_DECLARE_DATA proxy_balancer_module;

		@@ -262,13 +263,14 @@ static proxy_worker find_session_route(proxy_balancer balancer,
		* b a d c d a c d b d ...
		*
		*/

		static proxy_worker find_best_byrequests(proxy_balancer balancer,
		request_rec *r)
		{
		int i;
		int total_factor = 0;
		proxy_worker worker = (proxy_worker )balancer->workers->elts;
		proxy_worker *candidate = NULL;
		proxy_worker *mycandidate = NULL;

		/* First try to see if we have available candidate */
		for (i = 0; i < balancer->workers->nelts; i++) {
		@@ -286,18 +288,18 @@ static proxy_worker find_best_byrequests(proxy_balancer balancer,
		if (PROXY_WORKER_IS_USABLE(worker)) {
		worker->s->lbstatus += worker->s->lbfactor;
		total_factor += worker->s->lbfactor;
		if (!candidate \|\| worker->s->lbstatus > candidate->s->lbstatus)
		candidate = worker;
		if (!mycandidate \|\| worker->s->lbstatus > mycandidate->s->lbstatus)
		mycandidate = worker;
		}
		worker++;
		}

		if (candidate) {
		candidate->s->lbstatus -= total_factor;
		candidate->s->elected++;
		if (mycandidate) {
		mycandidate->s->lbstatus -= total_factor;
		mycandidate->s->elected++;
		}

		return candidate;
		return mycandidate;
		}

		/*
		@@ -324,7 +326,7 @@ static proxy_worker find_best_bytraffic(proxy_balancer balancer,
		apr_off_t mytraffic = 0;
		apr_off_t curmin = 0;
		proxy_worker worker = (proxy_worker )balancer->workers->elts;
		proxy_worker *candidate = NULL;
		proxy_worker *mycandidate = NULL;

		/* First try to see if we have available candidate */
		for (i = 0; i < balancer->workers->nelts; i++) {
		@@ -342,19 +344,19 @@ static proxy_worker find_best_bytraffic(proxy_balancer balancer,
		if (PROXY_WORKER_IS_USABLE(worker)) {
		mytraffic = (worker->s->transferred/worker->s->lbfactor) +
		(worker->s->read/worker->s->lbfactor);
		if (!candidate \|\| mytraffic < curmin) {
		candidate = worker;
		if (!mycandidate \|\| mytraffic < curmin) {
		mycandidate = worker;
		curmin = mytraffic;
		}
		}
		worker++;
		}

		if (candidate) {
		candidate->s->elected++;
		if (mycandidate) {
		mycandidate->s->elected++;
		}

		return candidate;
		return mycandidate;
		}

		static proxy_worker find_best_worker(proxy_balancer balancer,
		@@ -365,14 +367,12 @@ static proxy_worker find_best_worker(proxy_balancer balancer,
		if (PROXY_THREAD_LOCK(balancer) != APR_SUCCESS)
		return NULL;

		if (balancer->lbmethod == lbmethod_requests) {
		candidate = find_best_byrequests(balancer, r);
		} else if (balancer->lbmethod == lbmethod_traffic) {
		candidate = find_best_bytraffic(balancer, r);
		} else {
		candidate = (*balancer->lbmethod->finder)(balancer, r);

		/*
		PROXY_THREAD_UNLOCK(balancer);
		return NULL;
		}
		*/

		PROXY_THREAD_UNLOCK(balancer);

		@@ -657,19 +657,16 @@ static int balancer_handler(request_rec *r)
		bsel->max_attempts_set = 1;
		}
		if ((val = apr_table_get(params, "lm"))) {
		int ival = atoi(val);
		switch(ival) {
		case 0:
		break;
		case lbmethod_traffic:
		bsel->lbmethod = lbmethod_traffic;
		break;
		case lbmethod_requests:
		bsel->lbmethod = lbmethod_requests;
		break;
		default:
		struct proxy_balancer_method *ent =
		(struct proxy_balancer_method *) conf->lbmethods->elts;
		int i;
		for (i = 0; i < conf->lbmethods->nelts; i++) {
		if (!strcasecmp(val, ent->name)) {
		bsel->lbmethod = ent;
		break;
		}
		ent++;
		}
		}
		}
		if (wsel) {
		@@ -755,8 +752,7 @@ static int balancer_handler(request_rec *r)
		apr_time_sec(balancer->timeout));
		ap_rprintf(r, "<td>%d</td>\n", balancer->max_attempts);
		ap_rprintf(r, "<td>%s</td>\n",
		balancer->lbmethod == lbmethod_requests ? "Requests" :
		balancer->lbmethod == lbmethod_traffic ? "Traffic" : "Unknown");
		balancer->lbmethod->name);
		ap_rputs("</table>\n", r);
		ap_rputs("\n\n<table border=\"0\"><tr>"
		"<th>Scheme</th><th>Host</th>"
		@@ -834,10 +830,17 @@ static int balancer_handler(request_rec *r)
		ap_rprintf(r, "value=\"%d\"></td></tr>\n",
		bsel->max_attempts);
		ap_rputs("<tr><td>LB Method:</td><td><select name=\"lm\">", r);
		ap_rprintf(r, "<option value=\"%d\" %s>Requests</option>", lbmethod_requests,
		bsel->lbmethod == lbmethod_requests ? "selected" : "");
		ap_rprintf(r, "<option value=\"%d\" %s>Traffic</option>", lbmethod_traffic,
		bsel->lbmethod == lbmethod_traffic ? "selected" : "");
		{
		struct proxy_balancer_method *ent =
		(struct proxy_balancer_method *) conf->lbmethods->elts;
		int i;
		for (i = 0; i < conf->lbmethods->nelts; i++) {
		ap_rprintf(r, "<option value=\"%s\" %s>%s</option>", ent->name,
		(!strcasecmp(bsel->lbmethod->name, ent->name)) ? "selected" : "",
		ent->name);
		ent++;
		}
		}
		ap_rputs("</select></td></tr>\n", r);
		ap_rputs("<tr><td colspan=2><input type=submit value=\"Submit\"></td></tr>\n", r);
		ap_rvputs(r, "</table>\n<input type=hidden name=\"b\" ", NULL);
		@@ -871,6 +874,30 @@ static void child_init(apr_pool_t p, server_rec s)

		}

		/*
		* How to add additional lbmethods:
		* 1. Create func which determines "best" candidate worker
		* (eg: find_best_bytraffic, above)
		* 2. Create proxy_balancer_method struct which
		* defines the method and add it to
		* available server methods using
		* the proxy_hook_load_lbmethods hook
		* (eg: add_lbmethods below).
		*/
		static int add_lbmethods(proxy_server_conf *conf)
		{
		proxy_balancer_method *new;

		new = apr_array_push(conf->lbmethods);
		new->name = "byrequests";
		new->finder = find_best_byrequests;
		new = apr_array_push(conf->lbmethods);
		new->name = "bytraffic";
		new->finder = find_best_bytraffic;

		return OK;
		}

		static void ap_proxy_balancer_register_hook(apr_pool_t *p)
		{
		/* Only the mpm_winnt has child init hook handler.
		@@ -884,6 +911,7 @@ static void ap_proxy_balancer_register_hook(apr_pool_t *p)
		proxy_hook_pre_request(proxy_balancer_pre_request, NULL, NULL, APR_HOOK_FIRST);
		proxy_hook_post_request(proxy_balancer_post_request, NULL, NULL, APR_HOOK_FIRST);
		proxy_hook_canon_handler(proxy_balancer_canon, NULL, NULL, APR_HOOK_FIRST);
		proxy_hook_load_lbmethods(add_lbmethods, NULL, NULL, APR_HOOK_FIRST);
		}

		module AP_MODULE_DECLARE_DATA proxy_balancer_module = {

modules/proxy/proxy_util.c

+15 −1

Original line number	Diff line number	Diff line
		@@ -1155,6 +1155,8 @@ PROXY_DECLARE(const char ) ap_proxy_add_balancer(proxy_balancer *balancer,
		const char *url)
		{
		char c, q, *uri = apr_pstrdup(p, url);
		int i;
		proxy_balancer_method *lbmethod;

		c = strchr(uri, ':');
		if (c == NULL \|\| c[1] != '/' \|\| c[2] != '/' \|\| c[3] == '\0')
		@@ -1167,8 +1169,20 @@ PROXY_DECLARE(const char ) ap_proxy_add_balancer(proxy_balancer *balancer,
		*balancer = apr_array_push(conf->balancers);
		memset(*balancer, 0, sizeof(proxy_balancer));

		/*
		* NOTE: The default method is byrequests, which we assume
		* exists!
		*/
		lbmethod = (proxy_balancer_method *)conf->lbmethods->elts;
		for (i = 0; i < conf->lbmethods->nelts; i++) {
		if (!strcasecmp(lbmethod->name, "byrequests")) {
		break;
		}
		lbmethod++;
		}

		(*balancer)->name = uri;
		(*balancer)->lbmethod = lbmethod_requests;
		(*balancer)->lbmethod = lbmethod;
		(*balancer)->workers = apr_array_make(p, 5, sizeof(proxy_worker));
		/* XXX Is this a right place to create mutex */
		#if APR_HAS_THREADS

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