mirrors/haproxy
1
0
Fork 0
mirror of https://git.haproxy.org/git/haproxy.git/ synced 2025-08-06 23:27:04 +02:00
Code Issues Projects Releases Wiki Activity
2d3d94cf23
haproxy/src/backend.c
Willy Tarreau 2d3d94cf23 [MINOR] replace srv_close_with_err() with http_server_error() 
The new function looks like the previous one except that it operates
at the stream interface level and assumes an already closed SI.

Also remove some old unused occurrences of srv_close_with_err().
2008-11-30 20:28:57 +01:00

2072 lines
58 KiB
C
Raw Blame History

/*
* Backend variables and functions.
*
* Copyright 2000-2008 Willy Tarreau <w@1wt.eu>
*
* 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.
*
*/
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <syslog.h>
#include <string.h>
#include <ctype.h>
#include <common/compat.h>
#include <common/config.h>
#include <common/debug.h>
#include <common/eb32tree.h>
#include <common/ticks.h>
#include <common/time.h>
#include <types/global.h>
#include <proto/acl.h>
#include <proto/backend.h>
#include <proto/client.h>
#include <proto/fd.h>
#include <proto/httperr.h>
#include <proto/log.h>
#include <proto/proto_http.h>
#include <proto/proto_tcp.h>
#include <proto/queue.h>
#include <proto/session.h>
#include <proto/stream_sock.h>
#include <proto/task.h>
#ifdef CONFIG_HAP_TCPSPLICE
#include <libtcpsplice.h>
#endif
static inline void fwrr_remove_from_tree(struct server *s);
static inline void fwrr_queue_by_weight(struct eb_root *root, struct server *s);
static inline void fwrr_dequeue_srv(struct server *s);
static void fwrr_get_srv(struct server *s);
static void fwrr_queue_srv(struct server *s);
/* This function returns non-zero if a server with the given weight and state
* is usable for LB, otherwise zero.
*/
static inline int srv_is_usable(int state, int weight)
{
if (!weight)
return 0;
if (state & SRV_GOINGDOWN)
return 0;
if (!(state & SRV_RUNNING))
return 0;
return 1;
}
/*
* This function recounts the number of usable active and backup servers for
* proxy <p>. These numbers are returned into the p->srv_act and p->srv_bck.
* This function also recomputes the total active and backup weights. However,
* it does not update tot_weight nor tot_used. Use update_backend_weight() for
* this.
*/
static void recount_servers(struct proxy *px)
{
struct server *srv;
px->srv_act = px->srv_bck = 0;
px->lbprm.tot_wact = px->lbprm.tot_wbck = 0;
px->lbprm.fbck = NULL;
for (srv = px->srv; srv != NULL; srv = srv->next) {
if (!srv_is_usable(srv->state, srv->eweight))
continue;
if (srv->state & SRV_BACKUP) {
if (!px->srv_bck &&
!(px->options & PR_O_USE_ALL_BK))
px->lbprm.fbck = srv;
px->srv_bck++;
px->lbprm.tot_wbck += srv->eweight;
} else {
px->srv_act++;
px->lbprm.tot_wact += srv->eweight;
}
}
}
/* This function simply updates the backend's tot_weight and tot_used values
* after servers weights have been updated. It is designed to be used after
* recount_servers() or equivalent.
*/
static void update_backend_weight(struct proxy *px)
{
if (px->srv_act) {
px->lbprm.tot_weight = px->lbprm.tot_wact;
px->lbprm.tot_used = px->srv_act;
}
else if (px->lbprm.fbck) {
/* use only the first backup server */
px->lbprm.tot_weight = px->lbprm.fbck->eweight;
px->lbprm.tot_used = 1;
}
else {
px->lbprm.tot_weight = px->lbprm.tot_wbck;
px->lbprm.tot_used = px->srv_bck;
}
}
/* this function updates the map according to server <srv>'s new state */
static void map_set_server_status_down(struct server *srv)
{
struct proxy *p = srv->proxy;
if (srv->state == srv->prev_state &&
srv->eweight == srv->prev_eweight)
return;
if (srv_is_usable(srv->state, srv->eweight))
goto out_update_state;
/* FIXME: could be optimized since we know what changed */
recount_servers(p);
update_backend_weight(p);
p->lbprm.map.state |= PR_MAP_RECALC;
out_update_state:
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
}
/* This function updates the map according to server <srv>'s new state */
static void map_set_server_status_up(struct server *srv)
{
struct proxy *p = srv->proxy;
if (srv->state == srv->prev_state &&
srv->eweight == srv->prev_eweight)
return;
if (!srv_is_usable(srv->state, srv->eweight))
goto out_update_state;
/* FIXME: could be optimized since we know what changed */
recount_servers(p);
update_backend_weight(p);
p->lbprm.map.state |= PR_MAP_RECALC;
out_update_state:
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
}
/* This function recomputes the server map for proxy px. It relies on
* px->lbprm.tot_wact, tot_wbck, tot_used, tot_weight, so it must be
* called after recount_servers(). It also expects px->lbprm.map.srv
* to be allocated with the largest size needed. It updates tot_weight.
*/
void recalc_server_map(struct proxy *px)
{
int o, tot, flag;
struct server *cur, *best;
switch (px->lbprm.tot_used) {
case 0: /* no server */
px->lbprm.map.state &= ~PR_MAP_RECALC;
return;
case 1: /* only one server, just fill first entry */
tot = 1;
break;
default:
tot = px->lbprm.tot_weight;
break;
}
/* here we *know* that we have some servers */
if (px->srv_act)
flag = SRV_RUNNING;
else
flag = SRV_RUNNING | SRV_BACKUP;
/* this algorithm gives priority to the first server, which means that
* it will respect the declaration order for equivalent weights, and
* that whatever the weights, the first server called will always be
* the first declared. This is an important asumption for the backup
* case, where we want the first server only.
*/
for (cur = px->srv; cur; cur = cur->next)
cur->wscore = 0;
for (o = 0; o < tot; o++) {
int max = 0;
best = NULL;
for (cur = px->srv; cur; cur = cur->next) {
if (flag == (cur->state &
(SRV_RUNNING | SRV_GOINGDOWN | SRV_BACKUP))) {
int v;
/* If we are forced to return only one server, we don't want to
* go further, because we would return the wrong one due to
* divide overflow.
*/
if (tot == 1) {
best = cur;
/* note that best->wscore will be wrong but we don't care */
break;
}
cur->wscore += cur->eweight;
v = (cur->wscore + tot) / tot; /* result between 0 and 3 */
if (best == NULL || v > max) {
max = v;
best = cur;
}
}
}
px->lbprm.map.srv[o] = best;
best->wscore -= tot;
}
px->lbprm.map.state &= ~PR_MAP_RECALC;
}
/* This function is responsible of building the server MAP for map-based LB
* algorithms, allocating the map, and setting p->lbprm.wmult to the GCD of the
* weights if applicable. It should be called only once per proxy, at config
* time.
*/
void init_server_map(struct proxy *p)
{
struct server *srv;
int pgcd;
int act, bck;
p->lbprm.set_server_status_up = map_set_server_status_up;
p->lbprm.set_server_status_down = map_set_server_status_down;
p->lbprm.update_server_eweight = NULL;
if (!p->srv)
return;
/* We will factor the weights to reduce the table,
* using Euclide's largest common divisor algorithm
*/
pgcd = p->srv->uweight;
for (srv = p->srv->next; srv && pgcd > 1; srv = srv->next) {
int w = srv->uweight;
while (w) {
int t = pgcd % w;
pgcd = w;
w = t;
}
}
/* It is sometimes useful to know what factor to apply
* to the backend's effective weight to know its real
* weight.
*/
p->lbprm.wmult = pgcd;
act = bck = 0;
for (srv = p->srv; srv; srv = srv->next) {
srv->eweight = srv->uweight / pgcd;
srv->prev_eweight = srv->eweight;
srv->prev_state = srv->state;
if (srv->state & SRV_BACKUP)
bck += srv->eweight;
else
act += srv->eweight;
}
/* this is the largest map we will ever need for this servers list */
if (act < bck)
act = bck;
p->lbprm.map.srv = (struct server **)calloc(act, sizeof(struct server *));
/* recounts servers and their weights */
p->lbprm.map.state = PR_MAP_RECALC;
recount_servers(p);
update_backend_weight(p);
recalc_server_map(p);
}
/* This function updates the server trees according to server <srv>'s new
* state. It should be called when server <srv>'s status changes to down.
* It is not important whether the server was already down or not. It is not
* important either that the new state is completely down (the caller may not
* know all the variables of a server's state).
*/
static void fwrr_set_server_status_down(struct server *srv)
{
struct proxy *p = srv->proxy;
struct fwrr_group *grp;
if (srv->state == srv->prev_state &&
srv->eweight == srv->prev_eweight)
return;
if (srv_is_usable(srv->state, srv->eweight))
goto out_update_state;
if (!srv_is_usable(srv->prev_state, srv->prev_eweight))
/* server was already down */
goto out_update_backend;
grp = (srv->state & SRV_BACKUP) ? &p->lbprm.fwrr.bck : &p->lbprm.fwrr.act;
grp->next_weight -= srv->prev_eweight;
if (srv->state & SRV_BACKUP) {
p->lbprm.tot_wbck = p->lbprm.fwrr.bck.next_weight;
p->srv_bck--;
if (srv == p->lbprm.fbck) {
/* we lost the first backup server in a single-backup
* configuration, we must search another one.
*/
struct server *srv2 = p->lbprm.fbck;
do {
srv2 = srv2->next;
} while (srv2 &&
!((srv2->state & SRV_BACKUP) &&
srv_is_usable(srv2->state, srv2->eweight)));
p->lbprm.fbck = srv2;
}
} else {
p->lbprm.tot_wact = p->lbprm.fwrr.act.next_weight;
p->srv_act--;
}
fwrr_dequeue_srv(srv);
fwrr_remove_from_tree(srv);
out_update_backend:
/* check/update tot_used, tot_weight */
update_backend_weight(p);
out_update_state:
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
}
/* This function updates the server trees according to server <srv>'s new
* state. It should be called when server <srv>'s status changes to up.
* It is not important whether the server was already down or not. It is not
* important either that the new state is completely UP (the caller may not
* know all the variables of a server's state). This function will not change
* the weight of a server which was already up.
*/
static void fwrr_set_server_status_up(struct server *srv)
{
struct proxy *p = srv->proxy;
struct fwrr_group *grp;
if (srv->state == srv->prev_state &&
srv->eweight == srv->prev_eweight)
return;
if (!srv_is_usable(srv->state, srv->eweight))
goto out_update_state;
if (srv_is_usable(srv->prev_state, srv->prev_eweight))
/* server was already up */
goto out_update_backend;
grp = (srv->state & SRV_BACKUP) ? &p->lbprm.fwrr.bck : &p->lbprm.fwrr.act;
grp->next_weight += srv->eweight;
if (srv->state & SRV_BACKUP) {
p->lbprm.tot_wbck = p->lbprm.fwrr.bck.next_weight;
p->srv_bck++;
if (!(p->options & PR_O_USE_ALL_BK)) {
if (!p->lbprm.fbck) {
/* there was no backup server anymore */
p->lbprm.fbck = srv;
} else {
/* we may have restored a backup server prior to fbck,
* in which case it should replace it.
*/
struct server *srv2 = srv;
do {
srv2 = srv2->next;
} while (srv2 && (srv2 != p->lbprm.fbck));
if (srv2)
p->lbprm.fbck = srv;
}
}
} else {
p->lbprm.tot_wact = p->lbprm.fwrr.act.next_weight;
p->srv_act++;
}
/* note that eweight cannot be 0 here */
fwrr_get_srv(srv);
srv->npos = grp->curr_pos + (grp->next_weight + grp->curr_weight - grp->curr_pos) / srv->eweight;
fwrr_queue_srv(srv);
out_update_backend:
/* check/update tot_used, tot_weight */
update_backend_weight(p);
out_update_state:
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
}
/* This function must be called after an update to server <srv>'s effective
* weight. It may be called after a state change too.
*/
static void fwrr_update_server_weight(struct server *srv)
{
int old_state, new_state;
struct proxy *p = srv->proxy;
struct fwrr_group *grp;
if (srv->state == srv->prev_state &&
srv->eweight == srv->prev_eweight)
return;
/* If changing the server's weight changes its state, we simply apply
* the procedures we already have for status change. If the state
* remains down, the server is not in any tree, so it's as easy as
* updating its values. If the state remains up with different weights,
* there are some computations to perform to find a new place and
* possibly a new tree for this server.
*/
old_state = srv_is_usable(srv->prev_state, srv->prev_eweight);
new_state = srv_is_usable(srv->state, srv->eweight);
if (!old_state && !new_state) {
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
return;
}
else if (!old_state && new_state) {
fwrr_set_server_status_up(srv);
return;
}
else if (old_state && !new_state) {
fwrr_set_server_status_down(srv);
return;
}
grp = (srv->state & SRV_BACKUP) ? &p->lbprm.fwrr.bck : &p->lbprm.fwrr.act;
grp->next_weight = grp->next_weight - srv->prev_eweight + srv->eweight;
p->lbprm.tot_wact = p->lbprm.fwrr.act.next_weight;
p->lbprm.tot_wbck = p->lbprm.fwrr.bck.next_weight;
if (srv->lb_tree == grp->init) {
fwrr_dequeue_srv(srv);
fwrr_queue_by_weight(grp->init, srv);
}
else if (!srv->lb_tree) {
/* FIXME: server was down. This is not possible right now but
* may be needed soon for slowstart or graceful shutdown.
*/
fwrr_dequeue_srv(srv);
fwrr_get_srv(srv);
srv->npos = grp->curr_pos + (grp->next_weight + grp->curr_weight - grp->curr_pos) / srv->eweight;
fwrr_queue_srv(srv);
} else {
/* The server is either active or in the next queue. If it's
* still in the active queue and it has not consumed all of its
* places, let's adjust its next position.
*/
fwrr_get_srv(srv);
if (srv->eweight > 0) {
int prev_next = srv->npos;
int step = grp->next_weight / srv->eweight;
srv->npos = srv->lpos + step;
srv->rweight = 0;
if (srv->npos > prev_next)
srv->npos = prev_next;
if (srv->npos < grp->curr_pos + 2)
srv->npos = grp->curr_pos + step;
} else {
/* push it into the next tree */
srv->npos = grp->curr_pos + grp->curr_weight;
}
fwrr_dequeue_srv(srv);
fwrr_queue_srv(srv);
}
update_backend_weight(p);
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
}
/* Remove a server from a tree. It must have previously been dequeued. This
* function is meant to be called when a server is going down or has its
* weight disabled.
*/
static inline void fwrr_remove_from_tree(struct server *s)
{
s->lb_tree = NULL;
}
/* Queue a server in the weight tree <root>, assuming the weight is >0.
* We want to sort them by inverted weights, because we need to place
* heavy servers first in order to get a smooth distribution.
*/
static inline void fwrr_queue_by_weight(struct eb_root *root, struct server *s)
{
s->lb_node.key = SRV_EWGHT_MAX - s->eweight;
eb32_insert(root, &s->lb_node);
s->lb_tree = root;
}
/* This function is responsible for building the weight trees in case of fast
* weighted round-robin. It also sets p->lbprm.wdiv to the eweight to uweight
* ratio. Both active and backup groups are initialized.
*/
void fwrr_init_server_groups(struct proxy *p)
{
struct server *srv;
struct eb_root init_head = EB_ROOT;
p->lbprm.set_server_status_up = fwrr_set_server_status_up;
p->lbprm.set_server_status_down = fwrr_set_server_status_down;
p->lbprm.update_server_eweight = fwrr_update_server_weight;
p->lbprm.wdiv = BE_WEIGHT_SCALE;
for (srv = p->srv; srv; srv = srv->next) {
srv->prev_eweight = srv->eweight = srv->uweight * BE_WEIGHT_SCALE;
srv->prev_state = srv->state;
}
recount_servers(p);
update_backend_weight(p);
/* prepare the active servers group */
p->lbprm.fwrr.act.curr_pos = p->lbprm.fwrr.act.curr_weight =
p->lbprm.fwrr.act.next_weight = p->lbprm.tot_wact;
p->lbprm.fwrr.act.curr = p->lbprm.fwrr.act.t0 =
p->lbprm.fwrr.act.t1 = init_head;
p->lbprm.fwrr.act.init = &p->lbprm.fwrr.act.t0;
p->lbprm.fwrr.act.next = &p->lbprm.fwrr.act.t1;
/* prepare the backup servers group */
p->lbprm.fwrr.bck.curr_pos = p->lbprm.fwrr.bck.curr_weight =
p->lbprm.fwrr.bck.next_weight = p->lbprm.tot_wbck;
p->lbprm.fwrr.bck.curr = p->lbprm.fwrr.bck.t0 =
p->lbprm.fwrr.bck.t1 = init_head;
p->lbprm.fwrr.bck.init = &p->lbprm.fwrr.bck.t0;
p->lbprm.fwrr.bck.next = &p->lbprm.fwrr.bck.t1;
/* queue active and backup servers in two distinct groups */
for (srv = p->srv; srv; srv = srv->next) {
if (!srv_is_usable(srv->state, srv->eweight))
continue;
fwrr_queue_by_weight((srv->state & SRV_BACKUP) ?
p->lbprm.fwrr.bck.init :
p->lbprm.fwrr.act.init,
srv);
}
}
/* simply removes a server from a weight tree */
static inline void fwrr_dequeue_srv(struct server *s)
{
eb32_delete(&s->lb_node);
}
/* queues a server into the appropriate group and tree depending on its
* backup status, and ->npos. If the server is disabled, simply assign
* it to the NULL tree.
*/
static void fwrr_queue_srv(struct server *s)
{
struct proxy *p = s->proxy;
struct fwrr_group *grp;
grp = (s->state & SRV_BACKUP) ? &p->lbprm.fwrr.bck : &p->lbprm.fwrr.act;
/* Delay everything which does not fit into the window and everything
* which does not fit into the theorical new window.
*/
if (!srv_is_usable(s->state, s->eweight)) {
fwrr_remove_from_tree(s);
}
else if (s->eweight <= 0 ||
s->npos >= 2 * grp->curr_weight ||
s->npos >= grp->curr_weight + grp->next_weight) {
/* put into next tree, and readjust npos in case we could
* finally take this back to current. */
s->npos -= grp->curr_weight;
fwrr_queue_by_weight(grp->next, s);
}
else {
/* The sorting key is stored in units of s->npos * user_weight
* in order to avoid overflows. As stated in backend.h, the
* lower the scale, the rougher the weights modulation, and the
* higher the scale, the lower the number of servers without
* overflow. With this formula, the result is always positive,
* so we can use eb3<62>_insert().
*/
s->lb_node.key = SRV_UWGHT_RANGE * s->npos +
(unsigned)(SRV_EWGHT_MAX + s->rweight - s->eweight) / BE_WEIGHT_SCALE;
eb32_insert(&grp->curr, &s->lb_node);
s->lb_tree = &grp->curr;
}
}
/* prepares a server when extracting it from the "init" tree */
static inline void fwrr_get_srv_init(struct server *s)
{
s->npos = s->rweight = 0;
}
/* prepares a server when extracting it from the "next" tree */
static inline void fwrr_get_srv_next(struct server *s)
{
struct fwrr_group *grp = (s->state & SRV_BACKUP) ?
&s->proxy->lbprm.fwrr.bck :
&s->proxy->lbprm.fwrr.act;
s->npos += grp->curr_weight;
}
/* prepares a server when it was marked down */
static inline void fwrr_get_srv_down(struct server *s)
{
struct fwrr_group *grp = (s->state & SRV_BACKUP) ?
&s->proxy->lbprm.fwrr.bck :
&s->proxy->lbprm.fwrr.act;
s->npos = grp->curr_pos;
}
/* prepares a server when extracting it from its tree */
static void fwrr_get_srv(struct server *s)
{
struct proxy *p = s->proxy;
struct fwrr_group *grp = (s->state & SRV_BACKUP) ?
&p->lbprm.fwrr.bck :
&p->lbprm.fwrr.act;
if (s->lb_tree == grp->init) {
fwrr_get_srv_init(s);
}
else if (s->lb_tree == grp->next) {
fwrr_get_srv_next(s);
}
else if (s->lb_tree == NULL) {
fwrr_get_srv_down(s);
}
}
/* switches trees "init" and "next" for FWRR group <grp>. "init" should be empty
* when this happens, and "next" filled with servers sorted by weights.
*/
static inline void fwrr_switch_trees(struct fwrr_group *grp)
{
struct eb_root *swap;
swap = grp->init;
grp->init = grp->next;
grp->next = swap;
grp->curr_weight = grp->next_weight;
grp->curr_pos = grp->curr_weight;
}
/* return next server from the current tree in FWRR group <grp>, or a server
* from the "init" tree if appropriate. If both trees are empty, return NULL.
*/
static struct server *fwrr_get_server_from_group(struct fwrr_group *grp)
{
struct eb32_node *node;
struct server *s;
node = eb32_first(&grp->curr);
s = eb32_entry(node, struct server, lb_node);
if (!node || s->npos > grp->curr_pos) {
/* either we have no server left, or we have a hole */
struct eb32_node *node2;
node2 = eb32_first(grp->init);
if (node2) {
node = node2;
s = eb32_entry(node, struct server, lb_node);
fwrr_get_srv_init(s);
if (s->eweight == 0) /* FIXME: is it possible at all ? */
node = NULL;
}
}
if (node)
return s;
else
return NULL;
}
/* Computes next position of server <s> in the group. It is mandatory for <s>
* to have a non-zero, positive eweight.
*/
static inline void fwrr_update_position(struct fwrr_group *grp, struct server *s)
{
if (!s->npos) {
/* first time ever for this server */
s->lpos = grp->curr_pos;
s->npos = grp->curr_pos + grp->next_weight / s->eweight;
s->rweight += grp->next_weight % s->eweight;
if (s->rweight >= s->eweight) {
s->rweight -= s->eweight;
s->npos++;
}
} else {
s->lpos = s->npos;
s->npos += grp->next_weight / s->eweight;
s->rweight += grp->next_weight % s->eweight;
if (s->rweight >= s->eweight) {
s->rweight -= s->eweight;
s->npos++;
}
}
}
/* Return next server from the current tree in backend <p>, or a server from
* the init tree if appropriate. If both trees are empty, return NULL.
* Saturated servers are skipped and requeued.
*/
static struct server *fwrr_get_next_server(struct proxy *p, struct server *srvtoavoid)
{
struct server *srv, *full, *avoided;
struct fwrr_group *grp;
int switched;
if (p->srv_act)
grp = &p->lbprm.fwrr.act;
else if (p->lbprm.fbck)
return p->lbprm.fbck;
else if (p->srv_bck)
grp = &p->lbprm.fwrr.bck;
else
return NULL;
switched = 0;
avoided = NULL;
full = NULL; /* NULL-terminated list of saturated servers */
while (1) {
/* if we see an empty group, let's first try to collect weights
* which might have recently changed.
*/
if (!grp->curr_weight)
grp->curr_pos = grp->curr_weight = grp->next_weight;
/* get first server from the "current" tree. When the end of
* the tree is reached, we may have to switch, but only once.
*/
while (1) {
srv = fwrr_get_server_from_group(grp);
if (srv)
break;
if (switched) {
if (avoided) {
srv = avoided;
break;
}
goto requeue_servers;
}
switched = 1;
fwrr_switch_trees(grp);
}
/* OK, we have a server. However, it may be saturated, in which
* case we don't want to reconsider it for now. We'll update
* its position and dequeue it anyway, so that we can move it
* to a better place afterwards.
*/
fwrr_update_position(grp, srv);
fwrr_dequeue_srv(srv);
grp->curr_pos++;
if (!srv->maxconn || (!srv->nbpend && srv->served < srv_dynamic_maxconn(srv))) {
/* make sure it is not the server we are trying to exclude... */
if (srv != srvtoavoid || avoided)
break;
avoided = srv; /* ...but remember that is was selected yet avoided */
}
/* the server is saturated or avoided, let's chain it for later reinsertion */
srv->next_full = full;
full = srv;
}
/* OK, we got the best server, let's update it */
fwrr_queue_srv(srv);
requeue_servers:
/* Requeue all extracted servers. If full==srv then it was
* avoided (unsucessfully) and chained, omit it now.
*/
if (unlikely(full != NULL)) {
if (switched) {
/* the tree has switched, requeue all extracted servers
* into "init", because their place was lost, and only
* their weight matters.
*/
do {
if (likely(full != srv))
fwrr_queue_by_weight(grp->init, full);
full = full->next_full;
} while (full);
} else {
/* requeue all extracted servers just as if they were consumed
* so that they regain their expected place.
*/
do {
if (likely(full != srv))
fwrr_queue_srv(full);
full = full->next_full;
} while (full);
}
}
return srv;
}
/* Remove a server from a tree. It must have previously been dequeued. This
* function is meant to be called when a server is going down or has its
* weight disabled.
*/
static inline void fwlc_remove_from_tree(struct server *s)
{
s->lb_tree = NULL;
}
/* simply removes a server from a tree */
static inline void fwlc_dequeue_srv(struct server *s)
{
eb32_delete(&s->lb_node);
}
/* Queue a server in its associated tree, assuming the weight is >0.
* Servers are sorted by #conns/weight. To ensure maximum accuracy,
* we use #conns*SRV_EWGHT_MAX/eweight as the sorting key.
*/
static inline void fwlc_queue_srv(struct server *s)
{
s->lb_node.key = s->served * SRV_EWGHT_MAX / s->eweight;
eb32_insert(s->lb_tree, &s->lb_node);
}
/* Re-position the server in the FWLC tree after it has been assigned one
* connection or after it has released one. Note that it is possible that
* the server has been moved out of the tree due to failed health-checks.
*/
static void fwlc_srv_reposition(struct server *s)
{
if (!s->lb_tree)
return;
fwlc_dequeue_srv(s);
fwlc_queue_srv(s);
}
/* This function updates the server trees according to server <srv>'s new
* state. It should be called when server <srv>'s status changes to down.
* It is not important whether the server was already down or not. It is not
* important either that the new state is completely down (the caller may not
* know all the variables of a server's state).
*/
static void fwlc_set_server_status_down(struct server *srv)
{
struct proxy *p = srv->proxy;
if (srv->state == srv->prev_state &&
srv->eweight == srv->prev_eweight)
return;
if (srv_is_usable(srv->state, srv->eweight))
goto out_update_state;
if (!srv_is_usable(srv->prev_state, srv->prev_eweight))
/* server was already down */
goto out_update_backend;
if (srv->state & SRV_BACKUP) {
p->lbprm.tot_wbck -= srv->prev_eweight;
p->srv_bck--;
if (srv == p->lbprm.fbck) {
/* we lost the first backup server in a single-backup
* configuration, we must search another one.
*/
struct server *srv2 = p->lbprm.fbck;
do {
srv2 = srv2->next;
} while (srv2 &&
!((srv2->state & SRV_BACKUP) &&
srv_is_usable(srv2->state, srv2->eweight)));
p->lbprm.fbck = srv2;
}
} else {
p->lbprm.tot_wact -= srv->prev_eweight;
p->srv_act--;
}
fwlc_dequeue_srv(srv);
fwlc_remove_from_tree(srv);
out_update_backend:
/* check/update tot_used, tot_weight */
update_backend_weight(p);
out_update_state:
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
}
/* This function updates the server trees according to server <srv>'s new
* state. It should be called when server <srv>'s status changes to up.
* It is not important whether the server was already down or not. It is not
* important either that the new state is completely UP (the caller may not
* know all the variables of a server's state). This function will not change
* the weight of a server which was already up.
*/
static void fwlc_set_server_status_up(struct server *srv)
{
struct proxy *p = srv->proxy;
if (srv->state == srv->prev_state &&
srv->eweight == srv->prev_eweight)
return;
if (!srv_is_usable(srv->state, srv->eweight))
goto out_update_state;
if (srv_is_usable(srv->prev_state, srv->prev_eweight))
/* server was already up */
goto out_update_backend;
if (srv->state & SRV_BACKUP) {
srv->lb_tree = &p->lbprm.fwlc.bck;
p->lbprm.tot_wbck += srv->eweight;
p->srv_bck++;
if (!(p->options & PR_O_USE_ALL_BK)) {
if (!p->lbprm.fbck) {
/* there was no backup server anymore */
p->lbprm.fbck = srv;
} else {
/* we may have restored a backup server prior to fbck,
* in which case it should replace it.
*/
struct server *srv2 = srv;
do {
srv2 = srv2->next;
} while (srv2 && (srv2 != p->lbprm.fbck));
if (srv2)
p->lbprm.fbck = srv;
}
}
} else {
srv->lb_tree = &p->lbprm.fwlc.act;
p->lbprm.tot_wact += srv->eweight;
p->srv_act++;
}
/* note that eweight cannot be 0 here */
fwlc_queue_srv(srv);
out_update_backend:
/* check/update tot_used, tot_weight */
update_backend_weight(p);
out_update_state:
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
}
/* This function must be called after an update to server <srv>'s effective
* weight. It may be called after a state change too.
*/
static void fwlc_update_server_weight(struct server *srv)
{
int old_state, new_state;
struct proxy *p = srv->proxy;
if (srv->state == srv->prev_state &&
srv->eweight == srv->prev_eweight)
return;
/* If changing the server's weight changes its state, we simply apply
* the procedures we already have for status change. If the state
* remains down, the server is not in any tree, so it's as easy as
* updating its values. If the state remains up with different weights,
* there are some computations to perform to find a new place and
* possibly a new tree for this server.
*/
old_state = srv_is_usable(srv->prev_state, srv->prev_eweight);
new_state = srv_is_usable(srv->state, srv->eweight);
if (!old_state && !new_state) {
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
return;
}
else if (!old_state && new_state) {
fwlc_set_server_status_up(srv);
return;
}
else if (old_state && !new_state) {
fwlc_set_server_status_down(srv);
return;
}
if (srv->lb_tree)
fwlc_dequeue_srv(srv);
if (srv->state & SRV_BACKUP) {
p->lbprm.tot_wbck += srv->eweight - srv->prev_eweight;
srv->lb_tree = &p->lbprm.fwlc.bck;
} else {
p->lbprm.tot_wact += srv->eweight - srv->prev_eweight;
srv->lb_tree = &p->lbprm.fwlc.act;
}
fwlc_queue_srv(srv);
update_backend_weight(p);
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
}
/* This function is responsible for building the trees in case of fast
* weighted least-conns. It also sets p->lbprm.wdiv to the eweight to
* uweight ratio. Both active and backup groups are initialized.
*/
void fwlc_init_server_tree(struct proxy *p)
{
struct server *srv;
struct eb_root init_head = EB_ROOT;
p->lbprm.set_server_status_up = fwlc_set_server_status_up;
p->lbprm.set_server_status_down = fwlc_set_server_status_down;
p->lbprm.update_server_eweight = fwlc_update_server_weight;
p->lbprm.server_take_conn = fwlc_srv_reposition;
p->lbprm.server_drop_conn = fwlc_srv_reposition;
p->lbprm.wdiv = BE_WEIGHT_SCALE;
for (srv = p->srv; srv; srv = srv->next) {
srv->prev_eweight = srv->eweight = srv->uweight * BE_WEIGHT_SCALE;
srv->prev_state = srv->state;
}
recount_servers(p);
update_backend_weight(p);
p->lbprm.fwlc.act = init_head;
p->lbprm.fwlc.bck = init_head;
/* queue active and backup servers in two distinct groups */
for (srv = p->srv; srv; srv = srv->next) {
if (!srv_is_usable(srv->state, srv->eweight))
continue;
srv->lb_tree = (srv->state & SRV_BACKUP) ? &p->lbprm.fwlc.bck : &p->lbprm.fwlc.act;
fwlc_queue_srv(srv);
}
}
/* Return next server from the FWLC tree in backend <p>. If the tree is empty,
* return NULL. Saturated servers are skipped.
*/
static struct server *fwlc_get_next_server(struct proxy *p, struct server *srvtoavoid)
{
struct server *srv, *avoided;
struct eb32_node *node;
srv = avoided = NULL;
if (p->srv_act)
node = eb32_first(&p->lbprm.fwlc.act);
else if (p->lbprm.fbck)
return p->lbprm.fbck;
else if (p->srv_bck)
node = eb32_first(&p->lbprm.fwlc.bck);
else
return NULL;
while (node) {
/* OK, we have a server. However, it may be saturated, in which
* case we don't want to reconsider it for now, so we'll simply
* skip it. Same if it's the server we try to avoid, in which
* case we simply remember it for later use if needed.
*/
struct server *s;
s = eb32_entry(node, struct server, lb_node);
if (!s->maxconn || (!s->nbpend && s->served < srv_dynamic_maxconn(s))) {
if (s != srvtoavoid) {
srv = s;
break;
}
avoided = s;
}
node = eb32_next(node);
}
if (!srv)
srv = avoided;
return srv;
}
/*
* This function tries to find a running server for the proxy <px> following
* the URL parameter hash method. It looks for a specific parameter in the
* URL and hashes it to compute the server ID. This is useful to optimize
* performance by avoiding bounces between servers in contexts where sessions
* are shared but cookies are not usable. If the parameter is not found, NULL
* is returned. If any server is found, it will be returned. If no valid server
* is found, NULL is returned.
*/
struct server *get_server_ph(struct proxy *px, const char *uri, int uri_len)
{
unsigned long hash = 0;
const char *p;
const char *params;
int plen;
/* when tot_weight is 0 then so is srv_count */
if (px->lbprm.tot_weight == 0)
return NULL;
if ((p = memchr(uri, '?', uri_len)) == NULL)
return NULL;
if (px->lbprm.map.state & PR_MAP_RECALC)
recalc_server_map(px);
p++;
uri_len -= (p - uri);
plen = px->url_param_len;
params = p;
while (uri_len > plen) {
/* Look for the parameter name followed by an equal symbol */
if (params[plen] == '=') {
if (memcmp(params, px->url_param_name, plen) == 0) {
/* OK, we have the parameter here at <params>, and
* the value after the equal sign, at <p>
* skip the equal symbol
*/
p += plen + 1;
uri_len -= plen + 1;
while (uri_len && *p != '&') {
hash = *p + (hash << 6) + (hash << 16) - hash;
uri_len--;
p++;
}
return px->lbprm.map.srv[hash % px->lbprm.tot_weight];
}
}
/* skip to next parameter */
p = memchr(params, '&', uri_len);
if (!p)
return NULL;
p++;
uri_len -= (p - params);
params = p;
}
return NULL;
}
/*
* this does the same as the previous server_ph, but check the body contents
*/
struct server *get_server_ph_post(struct session *s)
{
unsigned long hash = 0;
struct http_txn *txn = &s->txn;
struct buffer *req = s->req;
struct http_msg *msg = &txn->req;
struct proxy *px = s->be;
unsigned int plen = px->url_param_len;
unsigned long body;
unsigned long len;
const char *params;
struct hdr_ctx ctx;
const char *p;
/* tot_weight appears to mean srv_count */
if (px->lbprm.tot_weight == 0)
return NULL;
body = msg->sol[msg->eoh] == '\r' ? msg->eoh + 2 : msg->eoh + 1;
len = req->l - body;
params = req->data + body;
if ( len == 0 )
return NULL;
if (px->lbprm.map.state & PR_MAP_RECALC)
recalc_server_map(px);
ctx.idx = 0;
/* if the message is chunked, we skip the chunk size, but use the value as len */
http_find_header2("Transfer-Encoding", 17, msg->sol, &txn->hdr_idx, &ctx);
if (ctx.idx && ctx.vlen >= 7 && strncasecmp(ctx.line+ctx.val, "chunked", 7) == 0) {
unsigned int chunk = 0;
while ( params < req->rlim && !HTTP_IS_CRLF(*params)) {
char c = *params;
if (ishex(c)) {
unsigned int hex = toupper(c) - '0';
if ( hex > 9 )
hex -= 'A' - '9' - 1;
chunk = (chunk << 4) | hex;
}
else
return NULL;
params++;
len--;
}
/* spec says we get CRLF */
if (HTTP_IS_CRLF(*params) && HTTP_IS_CRLF(params[1]))
params += 2;
else
return NULL;
/* ok we have some encoded length, just inspect the first chunk */
len = chunk;
}
p = params;
while (len > plen) {
/* Look for the parameter name followed by an equal symbol */
if (params[plen] == '=') {
if (memcmp(params, px->url_param_name, plen) == 0) {
/* OK, we have the parameter here at <params>, and
* the value after the equal sign, at <p>
* skip the equal symbol
*/
p += plen + 1;
len -= plen + 1;
while (len && *p != '&') {
if (unlikely(!HTTP_IS_TOKEN(*p))) {
/* if in a POST, body must be URI encoded or its not a URI.
* Do not interprete any possible binary data as a parameter.
*/
if (likely(HTTP_IS_LWS(*p))) /* eol, uncertain uri len */
break;
return NULL; /* oh, no; this is not uri-encoded.
* This body does not contain parameters.
*/
}
hash = *p + (hash << 6) + (hash << 16) - hash;
len--;
p++;
/* should we break if vlen exceeds limit? */
}
return px->lbprm.map.srv[hash % px->lbprm.tot_weight];
}
}
/* skip to next parameter */
p = memchr(params, '&', len);
if (!p)
return NULL;
p++;
len -= (p - params);
params = p;
}
return NULL;
}
/*
* This function applies the load-balancing algorithm to the session, as
* defined by the backend it is assigned to. The session is then marked as
* 'assigned'.
*
* This function MAY NOT be called with SN_ASSIGNED already set. If the session
* had a server previously assigned, it is rebalanced, trying to avoid the same
* server.
* The function tries to keep the original connection slot if it reconnects to
* the same server, otherwise it releases it and tries to offer it.
*
* It is illegal to call this function with a session in a queue.
*
* It may return :
* SRV_STATUS_OK if everything is OK. Session assigned to ->srv
* SRV_STATUS_NOSRV if no server is available. Session is not ASSIGNED
* SRV_STATUS_FULL if all servers are saturated. Session is not ASSIGNED
* SRV_STATUS_INTERNAL for other unrecoverable errors.
*
* Upon successful return, the session flag SN_ASSIGNED is set to indicate that
* it does not need to be called anymore. This means that s->srv can be trusted
* in balance and direct modes.
*
*/
int assign_server(struct session *s)
{
struct server *conn_slot;
int err;
#ifdef DEBUG_FULL
fprintf(stderr,"assign_server : s=%p\n",s);
#endif
err = SRV_STATUS_INTERNAL;
if (unlikely(s->pend_pos || s->flags & SN_ASSIGNED))
goto out_err;
s->prev_srv = s->prev_srv;
conn_slot = s->srv_conn;
/* We have to release any connection slot before applying any LB algo,
* otherwise we may erroneously end up with no available slot.
*/
if (conn_slot)
sess_change_server(s, NULL);
/* We will now try to find the good server and store it into <s->srv>.
* Note that <s->srv> may be NULL in case of dispatch or proxy mode,
* as well as if no server is available (check error code).
*/
s->srv = NULL;
if (s->be->lbprm.algo & BE_LB_ALGO) {
int len;
/* we must check if we have at least one server available */
if (!s->be->lbprm.tot_weight) {
err = SRV_STATUS_NOSRV;
goto out;
}
switch (s->be->lbprm.algo & BE_LB_ALGO) {
case BE_LB_ALGO_RR:
s->srv = fwrr_get_next_server(s->be, s->prev_srv);
if (!s->srv) {
err = SRV_STATUS_FULL;
goto out;
}
break;
case BE_LB_ALGO_LC:
s->srv = fwlc_get_next_server(s->be, s->prev_srv);
if (!s->srv) {
err = SRV_STATUS_FULL;
goto out;
}
break;
case BE_LB_ALGO_SH:
if (s->cli_addr.ss_family == AF_INET)
len = 4;
else if (s->cli_addr.ss_family == AF_INET6)
len = 16;
else {
/* unknown IP family */
err = SRV_STATUS_INTERNAL;
goto out;
}
s->srv = get_server_sh(s->be,
(void *)&((struct sockaddr_in *)&s->cli_addr)->sin_addr,
len);
break;
case BE_LB_ALGO_UH:
/* URI hashing */
s->srv = get_server_uh(s->be,
s->txn.req.sol + s->txn.req.sl.rq.u,
s->txn.req.sl.rq.u_l);
break;
case BE_LB_ALGO_PH:
/* URL Parameter hashing */
if (s->txn.meth == HTTP_METH_POST &&
memchr(s->txn.req.sol + s->txn.req.sl.rq.u, '&',
s->txn.req.sl.rq.u_l ) == NULL)
s->srv = get_server_ph_post(s);
else
s->srv = get_server_ph(s->be,
s->txn.req.sol + s->txn.req.sl.rq.u,
s->txn.req.sl.rq.u_l);
if (!s->srv) {
/* parameter not found, fall back to round robin on the map */
s->srv = get_server_rr_with_conns(s->be, s->prev_srv);
if (!s->srv) {
err = SRV_STATUS_FULL;
goto out;
}
}
break;
default:
/* unknown balancing algorithm */
err = SRV_STATUS_INTERNAL;
goto out;
}
if (s->srv != s->prev_srv) {
s->be->cum_lbconn++;
s->srv->cum_lbconn++;
}
}
else if (s->be->options & PR_O_HTTP_PROXY) {
if (!s->srv_addr.sin_addr.s_addr) {
err = SRV_STATUS_NOSRV;
goto out;
}
}
else if (!*(int *)&s->be->dispatch_addr.sin_addr &&
!(s->fe->options & PR_O_TRANSP)) {
err = SRV_STATUS_NOSRV;
goto out;
}
s->flags |= SN_ASSIGNED;
err = SRV_STATUS_OK;
out:
/* Either we take back our connection slot, or we offer it to someone
* else if we don't need it anymore.
*/
if (conn_slot) {
if (conn_slot == s->srv) {
sess_change_server(s, s->srv);
} else {
if (may_dequeue_tasks(conn_slot, s->be))
process_srv_queue(conn_slot);
}
}
out_err:
return err;
}
/*
* This function assigns a server address to a session, and sets SN_ADDR_SET.
* The address is taken from the currently assigned server, or from the
* dispatch or transparent address.
*
* It may return :
* SRV_STATUS_OK if everything is OK.
* SRV_STATUS_INTERNAL for other unrecoverable errors.
*
* Upon successful return, the session flag SN_ADDR_SET is set. This flag is
* not cleared, so it's to the caller to clear it if required.
*
*/
int assign_server_address(struct session *s)
{
#ifdef DEBUG_FULL
fprintf(stderr,"assign_server_address : s=%p\n",s);
#endif
if ((s->flags & SN_DIRECT) || (s->be->lbprm.algo & BE_LB_ALGO)) {
/* A server is necessarily known for this session */
if (!(s->flags & SN_ASSIGNED))
return SRV_STATUS_INTERNAL;
s->srv_addr = s->srv->addr;
/* if this server remaps proxied ports, we'll use
* the port the client connected to with an offset. */
if (s->srv->state & SRV_MAPPORTS) {
if (!(s->fe->options & PR_O_TRANSP) && !(s->flags & SN_FRT_ADDR_SET))
get_frt_addr(s);
if (s->frt_addr.ss_family == AF_INET) {
s->srv_addr.sin_port = htons(ntohs(s->srv_addr.sin_port) +
ntohs(((struct sockaddr_in *)&s->frt_addr)->sin_port));
} else {
s->srv_addr.sin_port = htons(ntohs(s->srv_addr.sin_port) +
ntohs(((struct sockaddr_in6 *)&s->frt_addr)->sin6_port));
}
}
}
else if (*(int *)&s->be->dispatch_addr.sin_addr) {
/* connect to the defined dispatch addr */
s->srv_addr = s->be->dispatch_addr;
}
else if (s->fe->options & PR_O_TRANSP) {
/* in transparent mode, use the original dest addr if no dispatch specified */
if (!(s->flags & SN_FRT_ADDR_SET))
get_frt_addr(s);
memcpy(&s->srv_addr, &s->frt_addr, MIN(sizeof(s->srv_addr), sizeof(s->frt_addr)));
/* when we support IPv6 on the backend, we may add other tests */
//qfprintf(stderr, "Cannot get original server address.\n");
//return SRV_STATUS_INTERNAL;
}
else if (s->be->options & PR_O_HTTP_PROXY) {
/* If HTTP PROXY option is set, then server is already assigned
* during incoming client request parsing. */
}
else {
/* no server and no LB algorithm ! */
return SRV_STATUS_INTERNAL;
}
s->flags |= SN_ADDR_SET;
return SRV_STATUS_OK;
}
/* This function assigns a server to session <s> if required, and can add the
* connection to either the assigned server's queue or to the proxy's queue.
* If ->srv_conn is set, the session is first released from the server.
* It may also be called with SN_DIRECT and/or SN_ASSIGNED though. It will
* be called before any connection and after any retry or redispatch occurs.
*
* It is not allowed to call this function with a session in a queue.
*
* Returns :
*
* SRV_STATUS_OK if everything is OK.
* SRV_STATUS_NOSRV if no server is available. s->srv = NULL.
* SRV_STATUS_QUEUED if the connection has been queued.
* SRV_STATUS_FULL if the server(s) is/are saturated and the
* connection could not be queued in s->srv,
* which may be NULL if we queue on the backend.
* SRV_STATUS_INTERNAL for other unrecoverable errors.
*
*/
int assign_server_and_queue(struct session *s)
{
struct pendconn *p;
int err;
if (s->pend_pos)
return SRV_STATUS_INTERNAL;
err = SRV_STATUS_OK;
if (!(s->flags & SN_ASSIGNED)) {
err = assign_server(s);
if (s->prev_srv) {
/* This session was previously assigned to a server. We have to
* update the session's and the server's stats :
* - if the server changed :
* - set TX_CK_DOWN if txn.flags was TX_CK_VALID
* - set SN_REDISP if it was successfully redispatched
* - increment srv->redispatches and be->redispatches
* - if the server remained the same : update retries.
*/
if (s->prev_srv != s->srv) {
if ((s->txn.flags & TX_CK_MASK) == TX_CK_VALID) {
s->txn.flags &= ~TX_CK_MASK;
s->txn.flags |= TX_CK_DOWN;
}
s->flags |= SN_REDISP;
s->prev_srv->redispatches++;
s->be->redispatches++;
} else {
s->prev_srv->retries++;
s->be->retries++;
}
}
}
switch (err) {
case SRV_STATUS_OK:
/* we have SN_ASSIGNED set */
if (!s->srv)
return SRV_STATUS_OK; /* dispatch or proxy mode */
/* If we already have a connection slot, no need to check any queue */
if (s->srv_conn == s->srv)
return SRV_STATUS_OK;
/* OK, this session already has an assigned server, but no
* connection slot yet. Either it is a redispatch, or it was
* assigned from persistence information (direct mode).
*/
if ((s->flags & SN_REDIRECTABLE) && s->srv->rdr_len) {
/* server scheduled for redirection, and already assigned. We
* don't want to go further nor check the queue.
*/
sess_change_server(s, s->srv); /* not really needed in fact */
return SRV_STATUS_OK;
}
/* We might have to queue this session if the assigned server is full.
* We know we have to queue it into the server's queue, so if a maxqueue
* is set on the server, we must also check that the server's queue is
* not full, in which case we have to return FULL.
*/
if (s->srv->maxconn &&
(s->srv->nbpend || s->srv->served >= srv_dynamic_maxconn(s->srv))) {
if (s->srv->maxqueue > 0 && s->srv->nbpend >= s->srv->maxqueue)
return SRV_STATUS_FULL;
p = pendconn_add(s);
if (p)
return SRV_STATUS_QUEUED;
else
return SRV_STATUS_INTERNAL;
}
/* OK, we can use this server. Let's reserve our place */
sess_change_server(s, s->srv);
return SRV_STATUS_OK;
case SRV_STATUS_FULL:
/* queue this session into the proxy's queue */
p = pendconn_add(s);
if (p)
return SRV_STATUS_QUEUED;
else
return SRV_STATUS_INTERNAL;
case SRV_STATUS_NOSRV:
return err;
case SRV_STATUS_INTERNAL:
return err;
default:
return SRV_STATUS_INTERNAL;
}
}
/*
* This function initiates a connection to the server assigned to this session
* (s->srv, s->srv_addr). It will assign a server if none is assigned yet.
* It can return one of :
* - SN_ERR_NONE if everything's OK
* - SN_ERR_SRVTO if there are no more servers
* - SN_ERR_SRVCL if the connection was refused by the server
* - SN_ERR_PRXCOND if the connection has been limited by the proxy (maxconn)
* - SN_ERR_RESOURCE if a system resource is lacking (eg: fd limits, ports, ...)
* - SN_ERR_INTERNAL for any other purely internal errors
* Additionnally, in the case of SN_ERR_RESOURCE, an emergency log will be emitted.
*/
int connect_server(struct session *s)
{
int fd, err;
if (!(s->flags & SN_ADDR_SET)) {
err = assign_server_address(s);
if (err != SRV_STATUS_OK)
return SN_ERR_INTERNAL;
}
if ((fd = s->req->cons->fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1) {
qfprintf(stderr, "Cannot get a server socket.\n");
if (errno == ENFILE)
send_log(s->be, LOG_EMERG,
"Proxy %s reached system FD limit at %d. Please check system tunables.\n",
s->be->id, maxfd);
else if (errno == EMFILE)
send_log(s->be, LOG_EMERG,
"Proxy %s reached process FD limit at %d. Please check 'ulimit-n' and restart.\n",
s->be->id, maxfd);
else if (errno == ENOBUFS || errno == ENOMEM)
send_log(s->be, LOG_EMERG,
"Proxy %s reached system memory limit at %d sockets. Please check system tunables.\n",
s->be->id, maxfd);
/* this is a resource error */
return SN_ERR_RESOURCE;
}
if (fd >= global.maxsock) {
/* do not log anything there, it's a normal condition when this option
* is used to serialize connections to a server !
*/
Alert("socket(): not enough free sockets. Raise -n argument. Giving up.\n");
close(fd);
return SN_ERR_PRXCOND; /* it is a configuration limit */
}
#ifdef CONFIG_HAP_TCPSPLICE
if ((s->fe->options & s->be->options) & PR_O_TCPSPLICE) {
/* TCP splicing supported by both FE and BE */
tcp_splice_initfd(s->cli_fd, fd);
}
#endif
if ((fcntl(fd, F_SETFL, O_NONBLOCK)==-1) ||
(setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, (char *) &one, sizeof(one)) == -1)) {
qfprintf(stderr,"Cannot set client socket to non blocking mode.\n");
close(fd);
return SN_ERR_INTERNAL;
}
if (s->be->options & PR_O_TCP_SRV_KA)
setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, (char *) &one, sizeof(one));
if (s->be->options & PR_O_TCP_NOLING)
setsockopt(fd, SOL_SOCKET, SO_LINGER, (struct linger *) &nolinger, sizeof(struct linger));
/* allow specific binding :
* - server-specific at first
* - proxy-specific next
*/
if (s->srv != NULL && s->srv->state & SRV_BIND_SRC) {
struct sockaddr_in *remote = NULL;
int ret, flags = 0;
#if defined(CONFIG_HAP_CTTPROXY) || defined(CONFIG_HAP_LINUX_TPROXY)
switch (s->srv->state & SRV_TPROXY_MASK) {
case SRV_TPROXY_ADDR:
remote = (struct sockaddr_in *)&s->srv->tproxy_addr;
flags = 3;
break;
case SRV_TPROXY_CLI:
flags |= 2;
/* fall through */
case SRV_TPROXY_CIP:
/* FIXME: what can we do if the client connects in IPv6 ? */
flags |= 1;
remote = (struct sockaddr_in *)&s->cli_addr;
break;
}
#endif
ret = tcpv4_bind_socket(fd, flags, &s->srv->source_addr, remote);
if (ret) {
close(fd);
if (ret == 1) {
Alert("Cannot bind to source address before connect() for server %s/%s. Aborting.\n",
s->be->id, s->srv->id);
send_log(s->be, LOG_EMERG,
"Cannot bind to source address before connect() for server %s/%s.\n",
s->be->id, s->srv->id);
} else {
Alert("Cannot bind to tproxy source address before connect() for server %s/%s. Aborting.\n",
s->be->id, s->srv->id);
send_log(s->be, LOG_EMERG,
"Cannot bind to tproxy source address before connect() for server %s/%s.\n",
s->be->id, s->srv->id);
}
return SN_ERR_RESOURCE;
}
}
else if (s->be->options & PR_O_BIND_SRC) {
struct sockaddr_in *remote = NULL;
int ret, flags = 0;
#if defined(CONFIG_HAP_CTTPROXY) || defined(CONFIG_HAP_LINUX_TPROXY)
switch (s->be->options & PR_O_TPXY_MASK) {
case PR_O_TPXY_ADDR:
remote = (struct sockaddr_in *)&s->be->tproxy_addr;
flags = 3;
break;
case PR_O_TPXY_CLI:
flags |= 2;
/* fall through */
case PR_O_TPXY_CIP:
/* FIXME: what can we do if the client connects in IPv6 ? */
flags |= 1;
remote = (struct sockaddr_in *)&s->cli_addr;
break;
}
#endif
ret = tcpv4_bind_socket(fd, flags, &s->be->source_addr, remote);
if (ret) {
close(fd);
if (ret == 1) {
Alert("Cannot bind to source address before connect() for proxy %s. Aborting.\n",
s->be->id);
send_log(s->be, LOG_EMERG,
"Cannot bind to source address before connect() for proxy %s.\n",
s->be->id);
} else {
Alert("Cannot bind to tproxy source address before connect() for proxy %s. Aborting.\n",
s->be->id);
send_log(s->be, LOG_EMERG,
"Cannot bind to tproxy source address before connect() for proxy %s.\n",
s->be->id);
}
return SN_ERR_RESOURCE;
}
}
if ((connect(fd, (struct sockaddr *)&s->srv_addr, sizeof(s->srv_addr)) == -1) &&
(errno != EINPROGRESS) && (errno != EALREADY) && (errno != EISCONN)) {
if (errno == EAGAIN || errno == EADDRINUSE) {
char *msg;
if (errno == EAGAIN) /* no free ports left, try again later */
msg = "no free ports";
else
msg = "local address already in use";
qfprintf(stderr,"Cannot connect: %s.\n",msg);
close(fd);
send_log(s->be, LOG_EMERG,
"Connect() failed for server %s/%s: %s.\n",
s->be->id, s->srv->id, msg);
return SN_ERR_RESOURCE;
} else if (errno == ETIMEDOUT) {
//qfprintf(stderr,"Connect(): ETIMEDOUT");
close(fd);
return SN_ERR_SRVTO;
} else {
// (errno == ECONNREFUSED || errno == ENETUNREACH || errno == EACCES || errno == EPERM)
//qfprintf(stderr,"Connect(): %d", errno);
close(fd);
return SN_ERR_SRVCL;
}
}
fdtab[fd].owner = s->req->cons;
fdtab[fd].state = FD_STCONN; /* connection in progress */
fdtab[fd].cb[DIR_RD].f = &stream_sock_read;
fdtab[fd].cb[DIR_RD].b = s->rep;
fdtab[fd].cb[DIR_WR].f = &stream_sock_write;
fdtab[fd].cb[DIR_WR].b = s->req;
fdtab[fd].peeraddr = (struct sockaddr *)&s->srv_addr;
fdtab[fd].peerlen = sizeof(s->srv_addr);
fd_insert(fd);
EV_FD_SET(fd, DIR_WR); /* for connect status */
s->req->cons->state = SI_ST_CON;
if (s->srv) {
s->flags |= SN_CURR_SESS;
s->srv->cur_sess++;
if (s->srv->cur_sess > s->srv->cur_sess_max)
s->srv->cur_sess_max = s->srv->cur_sess;
if (s->be->lbprm.server_take_conn)
s->be->lbprm.server_take_conn(s->srv);
}
s->req->wex = tick_add_ifset(now_ms, s->be->timeout.connect);
return SN_ERR_NONE; /* connection is OK */
}
/* This function performs the "redispatch" part of a connection attempt. It
* will assign a server if required, queue the connection if required, and
* handle errors that might arise at this level. It can change the server
* state. It will return 1 if it encounters an error, switches the server
* state, or has to queue a connection. Otherwise, it will return 0 indicating
* that the connection is ready to use.
*/
int srv_redispatch_connect(struct session *t)
{
int conn_err;
/* We know that we don't have any connection pending, so we will
* try to get a new one, and wait in this state if it's queued
*/
redispatch:
conn_err = assign_server_and_queue(t);
switch (conn_err) {
case SRV_STATUS_OK:
break;
case SRV_STATUS_FULL:
/* The server has reached its maxqueue limit. Either PR_O_REDISP is set
* and we can redispatch to another server, or it is not and we return
* 503. This only makes sense in DIRECT mode however, because normal LB
* algorithms would never select such a server, and hash algorithms
* would bring us on the same server again. Note that t->srv is set in
* this case.
*/
if ((t->flags & SN_DIRECT) && (t->be->options & PR_O_REDISP)) {
t->flags &= ~(SN_DIRECT | SN_ASSIGNED | SN_ADDR_SET);
t->prev_srv = t->srv;
goto redispatch;
}
if (!t->req->cons->err_type) {
t->req->cons->err_type = SI_ET_QUEUE_ERR;
t->req->cons->err_loc = t->srv;
}
t->srv->failed_conns++;
t->be->failed_conns++;
return 1;
case SRV_STATUS_NOSRV:
/* note: it is guaranteed that t->srv == NULL here */
if (!t->req->cons->err_type) {
t->req->cons->err_type = SI_ET_CONN_ERR;
t->req->cons->err_loc = NULL;
}
t->be->failed_conns++;
return 1;
case SRV_STATUS_QUEUED:
t->req->cons->exp = tick_add_ifset(now_ms, t->be->timeout.queue);
t->req->cons->state = SI_ST_QUE;
/* do nothing else and do not wake any other session up */
return 1;
case SRV_STATUS_INTERNAL:
default:
if (!t->req->cons->err_type) {
t->req->cons->err_type = SI_ET_CONN_OTHER;
t->req->cons->err_loc = t->srv;
}
if (t->srv)
t->srv->cum_sess++;
if (t->srv)
t->srv->failed_conns++;
t->be->failed_conns++;
/* release other sessions waiting for this server */
if (may_dequeue_tasks(t->srv, t->be))
process_srv_queue(t->srv);
return 1;
}
/* if we get here, it's because we got SRV_STATUS_OK, which also
* means that the connection has not been queued.
*/
return 0;
}
int be_downtime(struct proxy *px) {
if (px->lbprm.tot_weight && px->last_change < now.tv_sec) // ignore negative time
return px->down_time;
return now.tv_sec - px->last_change + px->down_time;
}
/* This function parses a "balance" statement in a backend section describing
* <curproxy>. It returns -1 if there is any error, otherwise zero. If it
* returns -1, it may write an error message into ther <err> buffer, for at
* most <errlen> bytes, trailing zero included. The trailing '\n' will not be
* written. The function must be called with <args> pointing to the first word
* after "balance".
*/
int backend_parse_balance(const char **args, char *err, int errlen, struct proxy *curproxy)
{
if (!*(args[0])) {
/* if no option is set, use round-robin by default */
curproxy->lbprm.algo &= ~BE_LB_ALGO;
curproxy->lbprm.algo |= BE_LB_ALGO_RR;
return 0;
}
if (!strcmp(args[0], "roundrobin")) {
curproxy->lbprm.algo &= ~BE_LB_ALGO;
curproxy->lbprm.algo |= BE_LB_ALGO_RR;
}
else if (!strcmp(args[0], "leastconn")) {
curproxy->lbprm.algo &= ~BE_LB_ALGO;
curproxy->lbprm.algo |= BE_LB_ALGO_LC;
}
else if (!strcmp(args[0], "source")) {
curproxy->lbprm.algo &= ~BE_LB_ALGO;
curproxy->lbprm.algo |= BE_LB_ALGO_SH;
}
else if (!strcmp(args[0], "uri")) {
int arg = 1;
curproxy->lbprm.algo &= ~BE_LB_ALGO;
curproxy->lbprm.algo |= BE_LB_ALGO_UH;
while (*args[arg]) {
if (!strcmp(args[arg], "len")) {
if (!*args[arg+1] || (atoi(args[arg+1]) <= 0)) {
snprintf(err, errlen, "'balance uri len' expects a positive integer (got '%s').", args[arg+1]);
return -1;
}
curproxy->uri_len_limit = atoi(args[arg+1]);
arg += 2;
}
else if (!strcmp(args[arg], "depth")) {
if (!*args[arg+1] || (atoi(args[arg+1]) <= 0)) {
snprintf(err, errlen, "'balance uri depth' expects a positive integer (got '%s').", args[arg+1]);
return -1;
}
/* hint: we store the position of the ending '/' (depth+1) so
* that we avoid a comparison while computing the hash.
*/
curproxy->uri_dirs_depth1 = atoi(args[arg+1]) + 1;
arg += 2;
}
else {
snprintf(err, errlen, "'balance uri' only accepts parameters 'len' and 'depth' (got '%s').", args[arg]);
return -1;
}
}
}
else if (!strcmp(args[0], "url_param")) {
if (!*args[1]) {
snprintf(err, errlen, "'balance url_param' requires an URL parameter name.");
return -1;
}
curproxy->lbprm.algo &= ~BE_LB_ALGO;
curproxy->lbprm.algo |= BE_LB_ALGO_PH;
free(curproxy->url_param_name);
curproxy->url_param_name = strdup(args[1]);
curproxy->url_param_len = strlen(args[1]);
if (*args[2]) {
if (strcmp(args[2], "check_post")) {
snprintf(err, errlen, "'balance url_param' only accepts check_post modifier.");
return -1;
}
if (*args[3]) {
/* TODO: maybe issue a warning if there is no value, no digits or too long */
curproxy->url_param_post_limit = str2ui(args[3]);
}
/* if no limit, or faul value in args[3], then default to a moderate wordlen */
if (!curproxy->url_param_post_limit)
curproxy->url_param_post_limit = 48;
else if ( curproxy->url_param_post_limit < 3 )
curproxy->url_param_post_limit = 3; /* minimum example: S=3 or \r\nS=6& */
}
}
else {
snprintf(err, errlen, "'balance' only supports 'roundrobin', 'leastconn', 'source', 'uri' and 'url_param' options.");
return -1;
}
return 0;
}
/************************************************************************/
/* All supported keywords must be declared here. */
/************************************************************************/
/* set test->i to the number of enabled servers on the proxy */
static int
acl_fetch_nbsrv(struct proxy *px, struct session *l4, void *l7, int dir,
struct acl_expr *expr, struct acl_test *test)
{
test->flags = ACL_TEST_F_VOL_TEST;
if (expr->arg_len) {
/* another proxy was designated, we must look for it */
for (px = proxy; px; px = px->next)
if ((px->cap & PR_CAP_BE) && !strcmp(px->id, expr->arg.str))
break;
}
if (!px)
return 0;
if (px->srv_act)
test->i = px->srv_act;
else if (px->lbprm.fbck)
test->i = 1;
else
test->i = px->srv_bck;
return 1;
}
/* Note: must not be declared <const> as its list will be overwritten */
static struct acl_kw_list acl_kws = {{ },{
{ "nbsrv", acl_parse_int, acl_fetch_nbsrv, acl_match_int, ACL_USE_NOTHING },
{ NULL, NULL, NULL, NULL },
}};
__attribute__((constructor))
static void __backend_init(void)
{
acl_register_keywords(&acl_kws);
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/
Reference in New Issue View Git Blame Copy Permalink