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Copy pathbackend.c
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4017 lines (3479 loc) · 122 KB
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/*
* Backend variables and functions.
*
* Copyright 2000-2013 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 <stdio.h>
#include <stdlib.h>
#include <syslog.h>
#include <string.h>
#include <ctype.h>
#include <sys/types.h>
#include <import/ceb64_tree.h>
#include <haproxy/api.h>
#include <haproxy/acl.h>
#include <haproxy/activity.h>
#include <haproxy/arg.h>
#include <haproxy/backend.h>
#include <haproxy/channel.h>
#include <haproxy/check.h>
#include <haproxy/counters.h>
#include <haproxy/frontend.h>
#include <haproxy/global.h>
#include <haproxy/hash.h>
#include <haproxy/http.h>
#include <haproxy/http_ana.h>
#include <haproxy/http_htx.h>
#include <haproxy/htx.h>
#include <haproxy/lb_chash.h>
#include <haproxy/lb_fas.h>
#include <haproxy/lb_fwlc.h>
#include <haproxy/lb_fwrr.h>
#include <haproxy/lb_map.h>
#include <haproxy/lb_ss.h>
#include <haproxy/log.h>
#include <haproxy/namespace.h>
#include <haproxy/obj_type.h>
#include <haproxy/payload.h>
#include <haproxy/proto_tcp.h>
#include <haproxy/protocol.h>
#include <haproxy/proxy.h>
#include <haproxy/queue.h>
#include <haproxy/sample.h>
#include <haproxy/sc_strm.h>
#include <haproxy/server.h>
#include <haproxy/session.h>
#include <haproxy/ssl_sock.h>
#include <haproxy/stconn.h>
#include <haproxy/stream.h>
#include <haproxy/task.h>
#include <haproxy/ticks.h>
#include <haproxy/time.h>
#include <haproxy/tools.h>
#include <haproxy/trace.h>
#define TRACE_SOURCE &trace_strm
struct list lb_ops_list = LIST_HEAD_INIT(lb_ops_list);
void lb_ops_register(struct lb_ops *ops)
{
LIST_APPEND(&lb_ops_list, &ops->link);
}
/* helper function to invoke the correct hash method */
unsigned int gen_hash(const struct proxy* px, const char* key, unsigned long len)
{
unsigned int hash;
switch (px->lbprm.algo & BE_LB_HASH_FUNC) {
case BE_LB_HFCN_DJB2:
hash = hash_djb2(key, len);
break;
case BE_LB_HFCN_WT6:
hash = hash_wt6(key, len);
break;
case BE_LB_HFCN_CRC32:
hash = hash_crc32(key, len);
break;
case BE_LB_HFCN_NONE:
/* use key as a hash. It MUST be in string format */
{
const char *_key = key;
hash = read_int64(&_key, _key + len);
}
break;
case BE_LB_HFCN_SDBM:
/* this is the default hash function */
default:
hash = hash_sdbm(key, len);
break;
}
if ((px->lbprm.algo & BE_LB_HASH_MOD) == BE_LB_HMOD_AVAL)
hash = full_hash(hash);
return hash;
}
/*
* 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.
* This functions is designed to be called before server's weight and state
* commit so it uses 'next' weight and states values.
*
* threads: this is the caller responsibility to lock data. For now, this
* function is called from lb modules, so it should be ok. But if you need to
* call it from another place, be careful (and update this comment).
*/
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;
list_for_each_entry(srv, &px->servers, el_px) {
if (!srv_willbe_usable(srv))
continue;
if (srv->flags & SRV_F_BACKUP) {
if (!px->srv_bck &&
!(px->options & PR_O_USE_ALL_BK))
px->lbprm.fbck = srv;
px->srv_bck++;
srv->cumulative_weight = px->lbprm.tot_wbck;
px->lbprm.tot_wbck += srv->next_eweight;
} else {
px->srv_act++;
srv->cumulative_weight = px->lbprm.tot_wact;
px->lbprm.tot_wact += srv->next_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.
*
* threads: this is the caller responsibility to lock data. For now, this
* function is called from lb modules, so it should be ok. But if you need to
* call it from another place, be careful (and update this comment).
*/
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->next_eweight;
px->lbprm.tot_used = 1;
}
else {
px->lbprm.tot_weight = px->lbprm.tot_wbck;
px->lbprm.tot_used = px->srv_bck;
}
}
/*
* This function tries to find a running server for the proxy <px> following
* the source hash method. Depending on the number of active/backup servers,
* it will either look for active servers, or for backup servers.
* If any server is found, it will be returned. If no valid server is found,
* NULL is returned.
*/
struct server *get_server_sh(struct proxy *px, const char *addr, int len, const struct server *avoid)
{
unsigned int h, l;
if (px->lbprm.tot_weight == 0)
return NULL;
l = h = 0;
/* note: we won't hash if there's only one server left */
if (px->lbprm.tot_used == 1)
goto hash_done;
while ((l + sizeof (int)) <= len) {
h ^= ntohl(*(unsigned int *)(&addr[l]));
l += sizeof (int);
}
/* FIXME: why don't we use gen_hash() here as well?
* -> we don't take into account hash function from "hash_type"
* options here..
*/
if ((px->lbprm.algo & BE_LB_HASH_MOD) == BE_LB_HMOD_AVAL)
h = full_hash(h);
hash_done:
if ((px->lbprm.algo & BE_LB_LKUP) == BE_LB_LKUP_CHTREE)
return chash_get_server_hash(px, h, avoid);
else
return map_get_server_hash(px, h);
}
/*
* This function tries to find a running server for the proxy <px> following
* the URI hash method. In order to optimize cache hits, the hash computation
* ends at the question mark. Depending on the number of active/backup servers,
* it will either look for active servers, or for backup servers.
* If any server is found, it will be returned. If no valid server is found,
* NULL is returned. The lbprm.arg_opt{1,2,3} values correspond respectively to
* the "whole" optional argument (boolean, bit0), the "len" argument (numeric)
* and the "depth" argument (numeric).
*
* This code was contributed by Guillaume Dallaire, who also selected this hash
* algorithm out of a tens because it gave him the best results.
*
*/
struct server *get_server_uh(struct proxy *px, char *uri, int uri_len, const struct server *avoid)
{
unsigned int hash = 0;
int c;
int slashes = 0;
const char *start, *end;
if (px->lbprm.tot_weight == 0)
return NULL;
/* note: we won't hash if there's only one server left */
if (px->lbprm.tot_used == 1)
goto hash_done;
if (px->lbprm.arg_opt2) // "len"
uri_len = MIN(uri_len, px->lbprm.arg_opt2);
start = end = uri;
while (uri_len--) {
c = *end;
if (c == '/') {
slashes++;
if (slashes == px->lbprm.arg_opt3) /* depth+1 */
break;
}
else if (c == '?' && !(px->lbprm.arg_opt1 & 1)) // "whole"
break;
end++;
}
hash = gen_hash(px, start, (end - start));
hash_done:
if ((px->lbprm.algo & BE_LB_LKUP) == BE_LB_LKUP_CHTREE)
return chash_get_server_hash(px, hash, avoid);
else
return map_get_server_hash(px, hash);
}
/*
* 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, const struct server *avoid)
{
unsigned int hash = 0;
const char *start, *end;
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;
p++;
uri_len -= (p - uri);
plen = px->lbprm.arg_len;
params = p;
while (uri_len > plen) {
/* Look for the parameter name followed by an equal symbol */
if (params[plen] == '=') {
if (memcmp(params, px->lbprm.arg_str, 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;
start = end = p;
uri_len -= plen + 1;
while (uri_len && *end != '&') {
uri_len--;
end++;
}
hash = gen_hash(px, start, (end - start));
if ((px->lbprm.algo & BE_LB_LKUP) == BE_LB_LKUP_CHTREE)
return chash_get_server_hash(px, hash, avoid);
else
return map_get_server_hash(px, hash);
}
}
/* 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 stream *s, const struct server *avoid)
{
unsigned int hash = 0;
struct channel *req = &s->req;
struct proxy *px = s->be;
struct htx *htx = htxbuf(&req->buf);
struct htx_blk *blk;
unsigned int plen = px->lbprm.arg_len;
unsigned long len;
const char *params, *p, *start, *end;
if (px->lbprm.tot_weight == 0)
return NULL;
p = params = NULL;
len = 0;
for (blk = htx_get_first_blk(htx); blk; blk = htx_get_next_blk(htx, blk)) {
enum htx_blk_type type = htx_get_blk_type(blk);
struct ist v;
if (type != HTX_BLK_DATA)
continue;
v = htx_get_blk_value(htx, blk);
p = params = v.ptr;
len = v.len;
break;
}
while (len > plen) {
/* Look for the parameter name followed by an equal symbol */
if (params[plen] == '=') {
if (memcmp(params, px->lbprm.arg_str, 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;
start = end = p;
len -= plen + 1;
while (len && *end != '&') {
if (unlikely(!HTTP_IS_TOKEN(*end))) {
/* if in a POST, body must be URI encoded or it's not a URI.
* Do not interpret any possible binary data as a parameter.
*/
if (likely(HTTP_IS_LWS(*end))) /* eol, uncertain uri len */
break;
return NULL; /* oh, no; this is not uri-encoded.
* This body does not contain parameters.
*/
}
len--;
end++;
/* should we break if vlen exceeds limit? */
}
hash = gen_hash(px, start, (end - start));
if ((px->lbprm.algo & BE_LB_LKUP) == BE_LB_LKUP_CHTREE)
return chash_get_server_hash(px, hash, avoid);
else
return map_get_server_hash(px, hash);
}
}
/* skip to next parameter */
p = memchr(params, '&', len);
if (!p)
return NULL;
p++;
len -= (p - params);
params = p;
}
return NULL;
}
/*
* This function tries to find a running server for the proxy <px> following
* the Header 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. When lbprm.arg_opt1 is set, the hash will only
* apply to the middle part of a domain name ("use_domain_only" option).
*/
struct server *get_server_hh(struct stream *s, const struct server *avoid)
{
unsigned int hash = 0;
struct proxy *px = s->be;
unsigned int plen = px->lbprm.arg_len;
unsigned long len;
const char *p;
const char *start, *end;
struct htx *htx = htxbuf(&s->req.buf);
struct http_hdr_ctx ctx = { .blk = NULL };
/* tot_weight appears to mean srv_count */
if (px->lbprm.tot_weight == 0)
return NULL;
/* note: we won't hash if there's only one server left */
if (px->lbprm.tot_used == 1)
goto hash_done;
http_find_header(htx, ist2(px->lbprm.arg_str, plen), &ctx, 0);
/* if the header is not found or empty, let's fallback to round robin */
if (!ctx.blk || !ctx.value.len)
return NULL;
/* Found a the param_name in the headers.
* we will compute the hash based on this value ctx.val.
*/
len = ctx.value.len;
p = ctx.value.ptr;
if (!px->lbprm.arg_opt1) {
hash = gen_hash(px, p, len);
} else {
int dohash = 0;
p += len;
/* special computation, use only main domain name, not tld/host
* going back from the end of string, start hashing at first
* dot stop at next.
* This is designed to work with the 'Host' header, and requires
* a special option to activate this.
*/
end = p;
while (len) {
if (dohash) {
/* Rewind the pointer until the previous char
* is a dot, this will allow to set the start
* position of the domain. */
if (*(p - 1) == '.')
break;
}
else if (*p == '.') {
/* The pointer is rewound to the dot before the
* tld, we memorize the end of the domain and
* can enter the domain processing. */
end = p;
dohash = 1;
}
p--;
len--;
}
start = p;
hash = gen_hash(px, start, (end - start));
}
hash_done:
if ((px->lbprm.algo & BE_LB_LKUP) == BE_LB_LKUP_CHTREE)
return chash_get_server_hash(px, hash, avoid);
else
return map_get_server_hash(px, hash);
}
/* RDP Cookie HASH. */
struct server *get_server_rch(struct stream *s, const struct server *avoid)
{
unsigned int hash = 0;
struct proxy *px = s->be;
unsigned long len;
int ret;
struct sample smp;
int rewind;
/* tot_weight appears to mean srv_count */
if (px->lbprm.tot_weight == 0)
return NULL;
memset(&smp, 0, sizeof(smp));
rewind = co_data(&s->req);
c_rew(&s->req, rewind);
ret = fetch_rdp_cookie_name(s, &smp, px->lbprm.arg_str, px->lbprm.arg_len);
len = smp.data.u.str.data;
c_adv(&s->req, rewind);
if (ret == 0 || (smp.flags & SMP_F_MAY_CHANGE) || len == 0)
return NULL;
/* note: we won't hash if there's only one server left */
if (px->lbprm.tot_used == 1)
goto hash_done;
/* Found the param_name in the headers.
* we will compute the hash based on this value ctx.val.
*/
hash = gen_hash(px, smp.data.u.str.area, len);
hash_done:
if ((px->lbprm.algo & BE_LB_LKUP) == BE_LB_LKUP_CHTREE)
return chash_get_server_hash(px, hash, avoid);
else
return map_get_server_hash(px, hash);
}
/* sample expression HASH. Returns NULL if the sample is not found or if there
* are no server, relying on the caller to fall back to round robin instead.
*/
struct server *get_server_expr(struct stream *s, const struct server *avoid)
{
struct proxy *px = s->be;
struct sample *smp;
unsigned int hash = 0;
if (px->lbprm.tot_weight == 0)
return NULL;
/* note: no need to hash if there's only one server left */
if (px->lbprm.tot_used == 1)
goto hash_done;
/* Note that if the hash-type doesn't hash the key, we must provide it
* as a string representing a number as it will be parsed by read_int64().
* Otherwise it's binary. The difference happens on samples returing
* ints (e.g. rand()) as well as IP addresses, which, when turned to
* binary, are just binary-encoded and cannot be parsed.
*/
smp = sample_fetch_as_type(px, s->sess, s, SMP_OPT_DIR_REQ | SMP_OPT_FINAL, px->lbprm.expr,
((px->lbprm.algo & BE_LB_HASH_FUNC) == BE_LB_HFCN_NONE) ? SMP_T_STR : SMP_T_BIN);
if (!smp)
return NULL;
/* We have the desired data. Let's hash it according to the configured
* options and algorithm.
*/
hash = gen_hash(px, smp->data.u.str.area, smp->data.u.str.data);
hash_done:
if ((px->lbprm.algo & BE_LB_LKUP) == BE_LB_LKUP_CHTREE)
return chash_get_server_hash(px, hash, avoid);
else
return map_get_server_hash(px, hash);
}
/* random value */
struct server *get_server_rnd(struct stream *s, const struct server *avoid)
{
unsigned int hash = 0;
struct proxy *px = s->be;
struct server *prev, *curr;
int draws = px->lbprm.arg_opt1; // number of draws
/* tot_weight appears to mean srv_count */
if (px->lbprm.tot_weight == 0)
return NULL;
curr = NULL;
do {
prev = curr;
hash = statistical_prng();
curr = chash_get_server_hash(px, hash, avoid);
if (!curr)
break;
/* compare the new server to the previous best choice and pick
* the one with the least currently served requests.
*/
if (prev && prev != curr) {
uint64_t wcurr = (uint64_t)curr->served * prev->cur_eweight;
uint64_t wprev = (uint64_t)prev->served * curr->cur_eweight;
if (wcurr > wprev)
curr = prev;
else if (wcurr == wprev && curr->counters.shared.tg && prev->counters.shared.tg) {
/* same load: pick the lowest weighted request rate */
wcurr = read_freq_ctr_period_estimate(&curr->counters.shared.tg[tgid - 1]->sess_per_sec, MS_TO_TICKS(1000));
wprev = read_freq_ctr_period_estimate(&prev->counters.shared.tg[tgid - 1]->sess_per_sec, MS_TO_TICKS(1000));
if (wprev * curr->cur_eweight < wcurr * prev->cur_eweight)
curr = prev;
}
}
} while (--draws > 0);
/* if the selected server is full, pretend we have none so that we reach
* the backend's queue instead.
*/
if (curr &&
(curr->queueslength || (curr->maxconn && curr->served >= srv_dynamic_maxconn(curr))))
curr = NULL;
return curr;
}
/*
* This function applies the load-balancing algorithm to the stream, as
* defined by the backend it is assigned to. The stream is then marked as
* 'assigned'.
*
* This function MAY NOT be called with SF_ASSIGNED already set. If the stream
* had a server previously assigned, it is rebalanced, trying to avoid the same
* server, which should still be present in target_srv(&s->target) before the call.
* 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 stream in a queue.
*
* It may return :
* SRV_STATUS_OK if everything is OK. ->srv and ->target are assigned.
* SRV_STATUS_NOSRV if no server is available. Stream is not ASSIGNED
* SRV_STATUS_FULL if all servers are saturated. Stream is not ASSIGNED
* SRV_STATUS_INTERNAL for other unrecoverable errors.
*
* Upon successful return, the stream flag SF_ASSIGNED is set to indicate that
* it does not need to be called anymore. This means that target_srv(&s->target)
* can be trusted in balance and direct modes.
*
*/
int assign_server(struct stream *s)
{
struct connection *conn = NULL;
struct server *conn_slot;
struct server *srv = NULL, *prev_srv;
int err;
err = SRV_STATUS_INTERNAL;
if (unlikely(s->pend_pos || s->flags & SF_ASSIGNED))
goto out_err;
prev_srv = objt_server(s->target);
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 <objt_server(s->target)>.
* Note that <objt_server(s->target)> may be NULL in case of dispatch or proxy mode,
* as well as if no server is available (check error code).
*/
srv = NULL;
stream_set_target(s, NULL);
if ((s->be->lbprm.algo & BE_LB_KIND) != BE_LB_KIND_HI &&
((s->sess->flags & SESS_FL_PREFER_LAST) ||
(s->be->options & PR_O_PREF_LAST))) {
struct sess_priv_conns *pconns;
list_for_each_entry(pconns, &s->sess->priv_conns, sess_el) {
struct server *tmpsrv = objt_server(pconns->target);
if (tmpsrv && tmpsrv->proxy == s->be &&
((s->sess->flags & SESS_FL_PREFER_LAST) ||
(!s->be->max_ka_queue ||
server_has_room(tmpsrv) || (
tmpsrv->queueslength + 1 < s->be->max_ka_queue))) &&
srv_currently_usable(tmpsrv)) {
list_for_each_entry(conn, &pconns->conn_list, sess_el) {
if (!(conn->flags & CO_FL_WAIT_XPRT)) {
srv = tmpsrv;
stream_set_srv_target(s, srv);
goto out_ok;
}
}
}
}
}
if (s->be->lbprm.algo & BE_LB_KIND) {
/* we must check if we have at least one server available */
if (!s->be->lbprm.tot_weight) {
err = SRV_STATUS_NOSRV;
goto out;
}
/* if there's some queue on the backend, with certain algos we
* know it's because all servers are full.
*/
if (s->be->queueslength && s->be->served && s->be->queueslength != s->be->beconn &&
(((s->be->lbprm.algo & (BE_LB_KIND|BE_LB_NEED|BE_LB_PARM)) == BE_LB_ALGO_FAS)|| // first
((s->be->lbprm.algo & (BE_LB_KIND|BE_LB_NEED|BE_LB_PARM)) == BE_LB_ALGO_RR) || // roundrobin
((s->be->lbprm.algo & (BE_LB_KIND|BE_LB_NEED|BE_LB_PARM)) == BE_LB_ALGO_SRR))) { // static-rr
err = SRV_STATUS_FULL;
goto out;
}
/* First check whether we need to fetch some data or simply call
* the LB lookup function. Only the hashing functions will need
* some input data in fact, and will support multiple algorithms.
*/
switch (s->be->lbprm.algo & BE_LB_LKUP) {
case BE_LB_LKUP_RRTREE:
srv = fwrr_get_next_server(s->be, prev_srv);
break;
case BE_LB_LKUP_FSTREE:
srv = fas_get_next_server(s->be, prev_srv);
break;
case BE_LB_LKUP_LCTREE:
srv = fwlc_get_next_server(s->be, prev_srv);
break;
case BE_LB_LKUP_CHTREE:
case BE_LB_LKUP_MAP:
if ((s->be->lbprm.algo & BE_LB_KIND) == BE_LB_KIND_RR) {
/* static-rr (map) or random (chash) */
if ((s->be->lbprm.algo & BE_LB_PARM) == BE_LB_RR_RANDOM)
srv = get_server_rnd(s, prev_srv);
else
srv = map_get_server_rr(s->be, prev_srv);
break;
}
else if ((s->be->lbprm.algo & BE_LB_KIND) != BE_LB_KIND_HI) {
/* unknown balancing algorithm */
err = SRV_STATUS_INTERNAL;
goto out;
}
switch (s->be->lbprm.algo & BE_LB_PARM) {
const struct sockaddr_storage *src;
case BE_LB_HASH_SRC:
src = sc_src(s->scf);
if (src && src->ss_family == AF_INET) {
srv = get_server_sh(s->be,
(void *)&((struct sockaddr_in *)src)->sin_addr,
4, prev_srv);
}
else if (src && src->ss_family == AF_INET6) {
srv = get_server_sh(s->be,
(void *)&((struct sockaddr_in6 *)src)->sin6_addr,
16, prev_srv);
}
break;
case BE_LB_HASH_URI:
/* URI hashing */
if (IS_HTX_STRM(s) && s->txn.http->req.msg_state >= HTTP_MSG_BODY) {
struct ist uri;
uri = htx_sl_req_uri(http_get_stline(htxbuf(&s->req.buf)));
if (s->be->lbprm.arg_opt1 & 2) {
struct http_uri_parser parser =
http_uri_parser_init(uri);
uri = http_parse_path(&parser);
if (!isttest(uri))
uri = ist("");
}
srv = get_server_uh(s->be, uri.ptr, uri.len, prev_srv);
}
break;
case BE_LB_HASH_PRM:
/* URL Parameter hashing */
if (IS_HTX_STRM(s) && s->txn.http->req.msg_state >= HTTP_MSG_BODY) {
struct ist uri;
uri = htx_sl_req_uri(http_get_stline(htxbuf(&s->req.buf)));
srv = get_server_ph(s->be, uri.ptr, uri.len, prev_srv);
if (!srv && s->txn.http->meth == HTTP_METH_POST)
srv = get_server_ph_post(s, prev_srv);
}
break;
case BE_LB_HASH_HDR:
/* Header Parameter hashing */
if (IS_HTX_STRM(s) && s->txn.http->req.msg_state >= HTTP_MSG_BODY)
srv = get_server_hh(s, prev_srv);
break;
case BE_LB_HASH_RDP:
/* RDP Cookie hashing */
srv = get_server_rch(s, prev_srv);
break;
case BE_LB_HASH_SMP:
/* sample expression hashing */
srv = get_server_expr(s, prev_srv);
break;
default:
/* unknown balancing algorithm */
err = SRV_STATUS_INTERNAL;
goto out;
}
/* If the hashing parameter was not found, let's fall
* back to round robin on the map.
*/
if (!srv) {
if ((s->be->lbprm.algo & BE_LB_LKUP) == BE_LB_LKUP_CHTREE)
srv = chash_get_next_server(s->be, prev_srv);
else
srv = map_get_server_rr(s->be, prev_srv);
}
/* end of map-based LB */
break;
default:
if ((s->be->lbprm.algo & BE_LB_KIND) == BE_LB_KIND_SA) {
/* some special algos that cannot be grouped together */
if ((s->be->lbprm.algo & BE_LB_PARM) == BE_LB_SA_SS)
srv = ss_get_server(s->be);
break;
}
/* unknown balancing algorithm */
err = SRV_STATUS_INTERNAL;
goto out;
}
if (!srv) {
err = SRV_STATUS_FULL;
goto out;
}
else if (srv != prev_srv) {
if (s->be_tgcounters)
_HA_ATOMIC_INC(&s->be_tgcounters->cum_lbconn);
if (srv->counters.shared.tg)
_HA_ATOMIC_INC(&srv->counters.shared.tg[tgid - 1]->cum_lbconn);
}
stream_set_srv_target(s, srv);
}
else {
err = SRV_STATUS_NOSRV;
goto out;
}
out_ok:
s->flags |= SF_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 == srv) {
sess_change_server(s, srv);
} else {
if (may_dequeue_tasks(conn_slot, s->be))
process_srv_queue(conn_slot);
}
}
out_err:
return err;
}
/* Allocate <*ss> address unless already set. Address is then set to the
* destination endpoint of <srv> server, or via <s> from a dispatch or
* transparent address.
*
* Note that no address is allocated if server relies on reverse HTTP.
*
* Returns SRV_STATUS_OK on success, or if already already set. Else an error
* code is returned and <*ss> is not allocated.
*/
static int alloc_dst_address(struct sockaddr_storage **ss,
struct server *srv, struct stream *s)
{
const struct sockaddr_storage *dst;
if (*ss)
return SRV_STATUS_OK;
if (srv && (srv->flags & SRV_F_RHTTP)) {
/* For reverse HTTP, destination address is unknown. */
return SRV_STATUS_OK;
}
if ((s->flags & SF_DIRECT) || (s->be->lbprm.algo & BE_LB_KIND)) {
/* A server is necessarily known for this stream */
if (!(s->flags & SF_ASSIGNED))
return SRV_STATUS_INTERNAL;
if (!sockaddr_alloc(ss, NULL, 0))
return SRV_STATUS_INTERNAL;
ASSUME_NONNULL(srv); /* srv is guaranteed by SF_ASSIGNED */
**ss = srv->addr;
set_host_port(*ss, srv->svc_port);
if (!is_addr(*ss)) {
/* if the server has no address, we use the same address
* the client asked, which is handy for remapping ports
* locally on multiple addresses at once. Nothing is done
* for AF_UNIX addresses.
*/
dst = sc_dst(s->scf);
if (dst && dst->ss_family == AF_INET) {
((struct sockaddr_in *)*ss)->sin_family = AF_INET;
((struct sockaddr_in *)*ss)->sin_addr =
((struct sockaddr_in *)dst)->sin_addr;
} else if (dst && dst->ss_family == AF_INET6) {
((struct sockaddr_in6 *)*ss)->sin6_family = AF_INET6;
((struct sockaddr_in6 *)*ss)->sin6_addr =
((struct sockaddr_in6 *)dst)->sin6_addr;
}
}
/* if this server remaps proxied ports, we'll use
* the port the client connected to with an offset. */
if ((srv->flags & SRV_F_MAPPORTS)) {
int base_port;
dst = sc_dst(s->scf);
if (dst) {
/* First, retrieve the port from the incoming connection */
base_port = get_host_port(dst);
/* Second, assign the outgoing connection's port */
base_port += get_host_port(*ss);
set_host_port(*ss, base_port);
}
}
}
else {
/* no server and no LB algorithm ! */
return SRV_STATUS_INTERNAL;
}
return SRV_STATUS_OK;
}
/* This function assigns a server to stream <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 stream is first released from the server.
* It may also be called with SF_DIRECT and/or SF_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 stream in a queue.
*
* Returns :
*
* SRV_STATUS_OK if everything is OK.
* SRV_STATUS_NOSRV if no server is available. objt_server(s->target) = 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 at the server's,
* which may be NULL if we queue on the backend.
* SRV_STATUS_INTERNAL for other unrecoverable errors.
*
*/
int assign_server_and_queue(struct stream *s)
{
struct pendconn *p;
struct server *srv;
int err;
if (s->pend_pos)
return SRV_STATUS_INTERNAL;
err = SRV_STATUS_OK;
if (!(s->flags & SF_ASSIGNED)) {
struct server *prev_srv = objt_server(s->target);
err = assign_server(s);
if (prev_srv) {
/* This stream was previously assigned to a server. We have to
* update the stream's and the server's stats :
* - if the server changed :
* - set TX_CK_DOWN if txn.flags was TX_CK_VALID
* - set SF_REDISP if it was successfully redispatched
* - increment srv->redispatches and be->redispatches
* - if the server remained the same : update retries.
*/
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