int assign_server(struct session *s)
{
struct connection *conn;
struct server *conn_slot;
struct server *srv, *prev_srv;
int err;
DPRINTF(stderr,"assign_server : s=%p\n",s);
err = SRV_STATUS_INTERNAL;
if (unlikely(s->pend_pos || s->flags & SN_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;
s->target = NULL;
conn = objt_conn(s->si[1].end);
if (conn &&
(conn->flags & CO_FL_CONNECTED) &&
objt_server(conn->target) && __objt_server(conn->target)->proxy == s->be &&
((s->txn.flags & TX_PREFER_LAST) ||
((s->be->options & PR_O_PREF_LAST) &&
(!s->be->max_ka_queue ||
server_has_room(__objt_server(conn->target)) ||
(__objt_server(conn->target)->nbpend + 1) < s->be->max_ka_queue))) &&
srv_is_usable(__objt_server(conn->target))) {
/* This session was relying on a server in a previous request
* and the proxy has "option prefer-last-server" set, so
* let's try to reuse the same server.
*/
srv = __objt_server(conn->target);
s->target = &srv->obj_type;
}
else 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;
}
/* 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) {
if (s->be->lbprm.algo & BE_LB_LKUP_CHTREE)
srv = chash_get_next_server(s->be, 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) {
case BE_LB_HASH_SRC:
conn = objt_conn(s->si[0].end);
if (conn && conn->addr.from.ss_family == AF_INET) {
srv = get_server_sh(s->be,
(void *)&((struct sockaddr_in *)&conn->addr.from)->sin_addr,
4);
}
else if (conn && conn->addr.from.ss_family == AF_INET6) {
srv = get_server_sh(s->be,
(void *)&((struct sockaddr_in6 *)&conn->addr.from)->sin6_addr,
16);
}
else {
/* unknown IP family */
err = SRV_STATUS_INTERNAL;
goto out;
}
break;
case BE_LB_HASH_URI:
/* URI hashing */
if (s->txn.req.msg_state < HTTP_MSG_BODY)
break;
srv = get_server_uh(s->be,
b_ptr(s->req.buf, -http_uri_rewind(&s->txn.req)),
s->txn.req.sl.rq.u_l);
break;
case BE_LB_HASH_PRM:
/* URL Parameter hashing */
if (s->txn.req.msg_state < HTTP_MSG_BODY)
break;
srv = get_server_ph(s->be,
b_ptr(s->req.buf, -http_uri_rewind(&s->txn.req)),
s->txn.req.sl.rq.u_l);
if (!srv && s->txn.meth == HTTP_METH_POST)
srv = get_server_ph_post(s);
break;
case BE_LB_HASH_HDR:
/* Header Parameter hashing */
if (s->txn.req.msg_state < HTTP_MSG_BODY)
break;
srv = get_server_hh(s);
break;
case BE_LB_HASH_RDP:
/* RDP Cookie hashing */
srv = get_server_rch(s);
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_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:
/* unknown balancing algorithm */
err = SRV_STATUS_INTERNAL;
goto out;
}
if (!srv) {
err = SRV_STATUS_FULL;
goto out;
}
else if (srv != prev_srv) {
s->be->be_counters.cum_lbconn++;
srv->counters.cum_lbconn++;
}
s->target = &srv->obj_type;
}
else if (s->be->options & (PR_O_DISPATCH | PR_O_TRANSP)) {
s->target = &s->be->obj_type;
}
else if ((s->be->options & PR_O_HTTP_PROXY) &&
(conn = objt_conn(s->si[1].end)) &&
is_addr(&conn->addr.to)) {
/* in proxy mode, we need a valid destination address */
s->target = &s->be->obj_type;
}
else {
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 == srv) {
sess_change_server(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 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. 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 session *s)
{
struct pendconn *p;
struct server *srv;
int err;
if (s->pend_pos)
return SRV_STATUS_INTERNAL;
err = SRV_STATUS_OK;
if (!(s->flags & SN_ASSIGNED)) {
struct server *prev_srv = objt_server(s->target);
err = assign_server(s);
if (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 (prev_srv != objt_server(s->target)) {
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;
prev_srv->counters.redispatches++;
s->be->be_counters.redispatches++;
} else {
prev_srv->counters.retries++;
s->be->be_counters.retries++;
}
}
}
switch (err) {
case SRV_STATUS_OK:
/* we have SN_ASSIGNED set */
srv = objt_server(s->target);
if (!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 == 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) && 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, 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 (srv->maxconn &&
(srv->nbpend || srv->served >= srv_dynamic_maxconn(srv))) {
if (srv->maxqueue > 0 && srv->nbpend >= 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, 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;
}
}
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_KIND) {
/* we must check if we have at least one server available */
if (!s->be->lbprm.tot_weight) {
err = SRV_STATUS_NOSRV;
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:
s->srv = fwrr_get_next_server(s->be, s->prev_srv);
break;
case BE_LB_LKUP_LCTREE:
s->srv = fwlc_get_next_server(s->be, s->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) {
if (s->be->lbprm.algo & BE_LB_LKUP_CHTREE)
s->srv = chash_get_next_server(s->be, s->prev_srv);
else
s->srv = map_get_server_rr(s->be, s->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) {
case BE_LB_HASH_SRC:
if (s->cli_addr.ss_family == AF_INET)
s->srv = get_server_sh(s->be,
(void *)&((struct sockaddr_in *)&s->cli_addr)->sin_addr,
4);
else if (s->cli_addr.ss_family == AF_INET6)
s->srv = get_server_sh(s->be,
(void *)&((struct sockaddr_in6 *)&s->cli_addr)->sin6_addr,
16);
else {
/* unknown IP family */
err = SRV_STATUS_INTERNAL;
goto out;
}
break;
case BE_LB_HASH_URI:
/* URI hashing */
if (s->txn.req.msg_state < HTTP_MSG_BODY)
break;
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_HASH_PRM:
/* URL Parameter hashing */
if (s->txn.req.msg_state < HTTP_MSG_BODY)
break;
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 && s->txn.meth == HTTP_METH_POST)
s->srv = get_server_ph_post(s);
break;
case BE_LB_HASH_HDR:
/* Header Parameter hashing */
if (s->txn.req.msg_state < HTTP_MSG_BODY)
break;
s->srv = get_server_hh(s);
break;
case BE_LB_HASH_RDP:
/* RDP Cookie hashing */
s->srv = get_server_rch(s);
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 (!s->srv) {
if (s->be->lbprm.algo & BE_LB_LKUP_CHTREE)
s->srv = chash_get_next_server(s->be, s->prev_srv);
else
s->srv = map_get_server_rr(s->be, s->prev_srv);
}
/* end of map-based LB */
break;
default:
/* unknown balancing algorithm */
err = SRV_STATUS_INTERNAL;
goto out;
}
if (!s->srv) {
err = SRV_STATUS_FULL;
goto out;
}
else if (s->srv != s->prev_srv) {
s->be->counters.cum_lbconn++;
s->srv->counters.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->be->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;
}
