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s4:messaging: add imessaging_init_discard_incoming()

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We often create imessaging contexts just for sending messages,
but we'll never process incoming messages because a temporary event
context was used and we just queue a lot of imessaging_post_state
structures with immediate events.

With imessaging_init_discard_incoming() we'll discard any incoming messages
unless we have pending irpc requests.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15201

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
This commit is contained in:
Stefan Metzmacher 2022-09-28 13:47:13 +02:00 committed by Ralph Boehme
parent 5d91ecf01d
commit a120fb1c72
3 changed files with 85 additions and 1 deletions
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72
source4/lib/messaging/messaging.c
View File

@ -429,6 +429,12 @@ static NTSTATUS imessaging_reinit(struct imessaging_context *msg)
TALLOC_FREE(msg->msg_dgm_ref);
if (msg->discard_incoming) {
msg->num_incoming_listeners = 0;
} else {
msg->num_incoming_listeners = 1;
}
msg->server_id.pid = getpid();
msg->msg_dgm_ref = messaging_dgm_ref(msg,
@ -469,7 +475,9 @@ NTSTATUS imessaging_reinit_all(void)
/*
create the listening socket and setup the dispatcher
*/
struct imessaging_context *imessaging_init(TALLOC_CTX *mem_ctx,
static struct imessaging_context *imessaging_init_internal(
TALLOC_CTX *mem_ctx,
bool discard_incoming,
struct loadparm_context *lp_ctx,
struct server_id server_id,
struct tevent_context *ev)
@ -490,6 +498,12 @@ struct imessaging_context *imessaging_init(TALLOC_CTX *mem_ctx,
return NULL;
}
msg->ev = ev;
msg->discard_incoming = discard_incoming;
if (msg->discard_incoming) {
msg->num_incoming_listeners = 0;
} else {
msg->num_incoming_listeners = 1;
}
talloc_set_destructor(msg, imessaging_context_destructor);
@ -601,6 +615,36 @@ fail:
return NULL;
}
/*
create the listening socket and setup the dispatcher
*/
struct imessaging_context *imessaging_init(TALLOC_CTX *mem_ctx,
struct loadparm_context *lp_ctx,
struct server_id server_id,
struct tevent_context *ev)
{
bool discard_incoming = false;
return imessaging_init_internal(mem_ctx,
discard_incoming,
lp_ctx,
server_id,
ev);
}
struct imessaging_context *imessaging_init_discard_incoming(
TALLOC_CTX *mem_ctx,
struct loadparm_context *lp_ctx,
struct server_id server_id,
struct tevent_context *ev)
{
bool discard_incoming = true;
return imessaging_init_internal(mem_ctx,
discard_incoming,
lp_ctx,
server_id,
ev);
}
struct imessaging_post_state {
struct imessaging_context *msg_ctx;
struct imessaging_post_state **busy_ref;
@ -697,6 +741,22 @@ static void imessaging_dgm_recv(struct tevent_context *ev,
return;
}
if (msg->num_incoming_listeners == 0) {
struct server_id_buf selfbuf;
message_hdr_get(&msg_type, &src, &dst, buf);
DBG_DEBUG("not listening - discarding message from "
"src[%s] to dst[%s] (self[%s]) type=0x%x "
"on %s event context\n",
server_id_str_buf(src, &srcbuf),
server_id_str_buf(dst, &dstbuf),
server_id_str_buf(msg->server_id, &selfbuf),
(unsigned)msg_type,
(ev != msg->ev) ? "different" : "main");
return;
}
if (ev != msg->ev) {
int ret;
ret = imessaging_post_self(msg, buf, buf_len);
@ -760,6 +820,7 @@ struct imessaging_context *imessaging_client_init(TALLOC_CTX *mem_ctx,
return imessaging_init(mem_ctx, lp_ctx, id, ev);
}
/*
a list of registered irpc server functions
*/
@ -975,6 +1036,12 @@ static int irpc_destructor(struct irpc_request *irpc)
{
if (irpc->callid != -1) {
idr_remove(irpc->msg_ctx->idr, irpc->callid);
if (irpc->msg_ctx->discard_incoming) {
SMB_ASSERT(irpc->msg_ctx->num_incoming_listeners > 0);
} else {
SMB_ASSERT(irpc->msg_ctx->num_incoming_listeners > 1);
}
irpc->msg_ctx->num_incoming_listeners -= 1;
irpc->callid = -1;
}
@ -1168,6 +1235,9 @@ static struct tevent_req *irpc_bh_raw_call_send(TALLOC_CTX *mem_ctx,
state->irpc->incoming.handler = irpc_bh_raw_call_incoming_handler;
state->irpc->incoming.private_data = req;
/* make sure we accept incoming messages */
SMB_ASSERT(state->irpc->msg_ctx->num_incoming_listeners < UINT64_MAX);
state->irpc->msg_ctx->num_incoming_listeners += 1;
talloc_set_destructor(state->irpc, irpc_destructor);
/* setup the header */

5
source4/lib/messaging/messaging.h
View File

@ -49,6 +49,11 @@ struct imessaging_context *imessaging_init(TALLOC_CTX *mem_ctx,
struct loadparm_context *lp_ctx,
struct server_id server_id,
struct tevent_context *ev);
struct imessaging_context *imessaging_init_discard_incoming(
TALLOC_CTX *mem_ctx,
struct loadparm_context *lp_ctx,
struct server_id server_id,
struct tevent_context *ev);
void imessaging_dgm_unref_ev(struct tevent_context *ev);
NTSTATUS imessaging_reinit_all(void);
int imessaging_cleanup(struct imessaging_context *msg);

9
source4/lib/messaging/messaging_internal.h
View File

@ -33,6 +33,15 @@ struct imessaging_context {
struct server_id_db *names;
struct timeval start_time;
void *msg_dgm_ref;
/*
* The number of instances waiting for incoming
* messages. By default it's always greater than 0.
*
* If it's 0 we'll discard incoming messages,
* see imessaging_init_discard_imcoming().
*/
bool discard_incoming;
uint64_t num_incoming_listeners;
};
NTSTATUS imessaging_register_extra_handlers(struct imessaging_context *msg);