Commit a5959d53 authored by Hans Schillstrom's avatar Hans Schillstrom Committed by Simon Horman
Browse files

IPVS: Handle Scheduling errors.



If ip_vs_conn_fill_param_persist return an error to ip_vs_sched_persist,
this error must propagate as ignored=-1 to ip_vs_schedule().
Errors from ip_vs_conn_new() in ip_vs_sched_persist() and ip_vs_schedule()
should also return *ignored=-1;

This patch just relies on the fact that ignored is 1 before calling
ip_vs_sched_persist().

Sent from Julian:
  "The new case when ip_vs_conn_fill_param_persist fails
   should set *ignored = -1, so that we can use NF_DROP,
   see below. *ignored = -1 should be also used for ip_vs_conn_new
   failure in ip_vs_sched_persist() and ip_vs_schedule().
   The new negative value should be handled in tcp,udp,sctp"

"To summarize:

- *ignored = 1:
      protocol tried to schedule (eg. on SYN), found svc but the
      svc/scheduler decides that this packet should be accepted with
      NF_ACCEPT because it must not be scheduled.

- *ignored = 0:
      scheduler can not find destination, so try bypass or
      return ICMP and then NF_DROP (ip_vs_leave).

- *ignored = -1:
      scheduler tried to schedule but fatal error occurred, eg.
      ip_vs_conn_new failure (ENOMEM) or ip_vs_sip_fill_param
      failure such as missing Call-ID, ENOMEM on skb_linearize
      or pe_data. In this case we should return NF_DROP without
      any attempts to send ICMP with ip_vs_leave."

More or less all ideas and input to this patch is work from
Julian Anastasov
Signed-off-by: default avatarHans Schillstrom <hans.schillstrom@ericsson.com>
Acked-by: default avatarJulian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarSimon Horman <horms@verge.net.au>
parent 37165226
......@@ -177,7 +177,7 @@ ip_vs_set_state(struct ip_vs_conn *cp, int direction,
return pp->state_transition(cp, direction, skb, pp);
}
static inline void
static inline int
ip_vs_conn_fill_param_persist(const struct ip_vs_service *svc,
struct sk_buff *skb, int protocol,
const union nf_inet_addr *caddr, __be16 cport,
......@@ -187,7 +187,9 @@ ip_vs_conn_fill_param_persist(const struct ip_vs_service *svc,
ip_vs_conn_fill_param(svc->af, protocol, caddr, cport, vaddr, vport, p);
p->pe = svc->pe;
if (p->pe && p->pe->fill_param)
p->pe->fill_param(p, skb);
return p->pe->fill_param(p, skb);
return 0;
}
/*
......@@ -200,7 +202,7 @@ ip_vs_conn_fill_param_persist(const struct ip_vs_service *svc,
static struct ip_vs_conn *
ip_vs_sched_persist(struct ip_vs_service *svc,
struct sk_buff *skb,
__be16 src_port, __be16 dst_port)
__be16 src_port, __be16 dst_port, int *ignored)
{
struct ip_vs_conn *cp = NULL;
struct ip_vs_iphdr iph;
......@@ -268,20 +270,27 @@ ip_vs_sched_persist(struct ip_vs_service *svc,
vaddr = &fwmark;
}
}
ip_vs_conn_fill_param_persist(svc, skb, protocol, &snet, 0,
vaddr, vport, &param);
/* return *ignored = -1 so NF_DROP can be used */
if (ip_vs_conn_fill_param_persist(svc, skb, protocol, &snet, 0,
vaddr, vport, &param) < 0) {
*ignored = -1;
return NULL;
}
}
/* Check if a template already exists */
ct = ip_vs_ct_in_get(&param);
if (!ct || !ip_vs_check_template(ct)) {
/* No template found or the dest of the connection
/*
* No template found or the dest of the connection
* template is not available.
* return *ignored=0 i.e. ICMP and NF_DROP
*/
dest = svc->scheduler->schedule(svc, skb);
if (!dest) {
IP_VS_DBG(1, "p-schedule: no dest found.\n");
kfree(param.pe_data);
*ignored = 0;
return NULL;
}
......@@ -296,6 +305,7 @@ ip_vs_sched_persist(struct ip_vs_service *svc,
IP_VS_CONN_F_TEMPLATE, dest, skb->mark);
if (ct == NULL) {
kfree(param.pe_data);
*ignored = -1;
return NULL;
}
......@@ -323,6 +333,7 @@ ip_vs_sched_persist(struct ip_vs_service *svc,
cp = ip_vs_conn_new(&param, &dest->addr, dport, flags, dest, skb->mark);
if (cp == NULL) {
ip_vs_conn_put(ct);
*ignored = -1;
return NULL;
}
......@@ -342,6 +353,21 @@ ip_vs_sched_persist(struct ip_vs_service *svc,
* It selects a server according to the virtual service, and
* creates a connection entry.
* Protocols supported: TCP, UDP
*
* Usage of *ignored
*
* 1 : protocol tried to schedule (eg. on SYN), found svc but the
* svc/scheduler decides that this packet should be accepted with
* NF_ACCEPT because it must not be scheduled.
*
* 0 : scheduler can not find destination, so try bypass or
* return ICMP and then NF_DROP (ip_vs_leave).
*
* -1 : scheduler tried to schedule but fatal error occurred, eg.
* ip_vs_conn_new failure (ENOMEM) or ip_vs_sip_fill_param
* failure such as missing Call-ID, ENOMEM on skb_linearize
* or pe_data. In this case we should return NF_DROP without
* any attempts to send ICMP with ip_vs_leave.
*/
struct ip_vs_conn *
ip_vs_schedule(struct ip_vs_service *svc, struct sk_buff *skb,
......@@ -372,11 +398,9 @@ ip_vs_schedule(struct ip_vs_service *svc, struct sk_buff *skb,
}
/*
* Do not schedule replies from local real server. It is risky
* for fwmark services but mostly for persistent services.
* Do not schedule replies from local real server.
*/
if ((!skb->dev || skb->dev->flags & IFF_LOOPBACK) &&
(svc->flags & IP_VS_SVC_F_PERSISTENT || svc->fwmark) &&
(cp = pp->conn_in_get(svc->af, skb, pp, &iph, iph.len, 1))) {
IP_VS_DBG_PKT(12, svc->af, pp, skb, 0,
"Not scheduling reply for existing connection");
......@@ -387,10 +411,10 @@ ip_vs_schedule(struct ip_vs_service *svc, struct sk_buff *skb,
/*
* Persistent service
*/
if (svc->flags & IP_VS_SVC_F_PERSISTENT) {
*ignored = 0;
return ip_vs_sched_persist(svc, skb, pptr[0], pptr[1]);
}
if (svc->flags & IP_VS_SVC_F_PERSISTENT)
return ip_vs_sched_persist(svc, skb, pptr[0], pptr[1], ignored);
*ignored = 0;
/*
* Non-persistent service
......@@ -403,8 +427,6 @@ ip_vs_schedule(struct ip_vs_service *svc, struct sk_buff *skb,
return NULL;
}
*ignored = 0;
dest = svc->scheduler->schedule(svc, skb);
if (dest == NULL) {
IP_VS_DBG(1, "Schedule: no dest found.\n");
......@@ -425,8 +447,10 @@ ip_vs_schedule(struct ip_vs_service *svc, struct sk_buff *skb,
cp = ip_vs_conn_new(&p, &dest->addr,
dest->port ? dest->port : pptr[1],
flags, dest, skb->mark);
if (!cp)
if (!cp) {
*ignored = -1;
return NULL;
}
}
IP_VS_DBG_BUF(6, "Schedule fwd:%c c:%s:%u v:%s:%u "
......
......@@ -47,13 +47,18 @@ sctp_conn_schedule(int af, struct sk_buff *skb, struct ip_vs_protocol *pp,
* incoming connection, and create a connection entry.
*/
*cpp = ip_vs_schedule(svc, skb, pp, &ignored);
if (!*cpp && !ignored) {
*verdict = ip_vs_leave(svc, skb, pp);
if (!*cpp && ignored <= 0) {
if (!ignored)
*verdict = ip_vs_leave(svc, skb, pp);
else {
ip_vs_service_put(svc);
*verdict = NF_DROP;
}
return 0;
}
ip_vs_service_put(svc);
}
/* NF_ACCEPT */
return 1;
}
......
......@@ -64,12 +64,18 @@ tcp_conn_schedule(int af, struct sk_buff *skb, struct ip_vs_protocol *pp,
* incoming connection, and create a connection entry.
*/
*cpp = ip_vs_schedule(svc, skb, pp, &ignored);
if (!*cpp && !ignored) {
*verdict = ip_vs_leave(svc, skb, pp);
if (!*cpp && ignored <= 0) {
if (!ignored)
*verdict = ip_vs_leave(svc, skb, pp);
else {
ip_vs_service_put(svc);
*verdict = NF_DROP;
}
return 0;
}
ip_vs_service_put(svc);
}
/* NF_ACCEPT */
return 1;
}
......
......@@ -63,12 +63,18 @@ udp_conn_schedule(int af, struct sk_buff *skb, struct ip_vs_protocol *pp,
* incoming connection, and create a connection entry.
*/
*cpp = ip_vs_schedule(svc, skb, pp, &ignored);
if (!*cpp && !ignored) {
*verdict = ip_vs_leave(svc, skb, pp);
if (!*cpp && ignored <= 0) {
if (!ignored)
*verdict = ip_vs_leave(svc, skb, pp);
else {
ip_vs_service_put(svc);
*verdict = NF_DROP;
}
return 0;
}
ip_vs_service_put(svc);
}
/* NF_ACCEPT */
return 1;
}
......
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