You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
111 lines
5.7 KiB
111 lines
5.7 KiB
From f94735eb76e634d7531f9c903113f64820c4cec0 Mon Sep 17 00:00:00 2001
|
|
From: Willy Tarreau <w@1wt.eu>
|
|
Date: Wed, 30 Jul 2014 08:56:35 +0200
|
|
Subject: [PATCH 3/3] BUG/MAJOR: tcp: fix a possible busy spinning loop in
|
|
content track-sc*
|
|
|
|
As a consequence of various recent changes on the sample conversion,
|
|
a corner case has emerged where it is possible to wait forever for a
|
|
sample in track-sc*.
|
|
|
|
The issue is caused by the fact that functions relying on sample_process()
|
|
don't all exactly work the same regarding the SMP_F_MAY_CHANGE flag and
|
|
the output result. Here it was possible to wait forever for an output
|
|
sample from stktable_fetch_key() without checking the SMP_OPT_FINAL flag.
|
|
As a result, if the client connects and closes without sending the data
|
|
and haproxy expects a sample which is capable of coming, it will ignore
|
|
this impossible case and will continue to wait.
|
|
|
|
This change adds control for SMP_OPT_FINAL before waiting for extra data.
|
|
The various relevant functions have been better documented regarding their
|
|
output values.
|
|
|
|
This fix must be backported to 1.5 since it appeared there.
|
|
(cherry picked from commit 6bcb0a84e7256f00793fa8ec8a0d6c19c3b22935)
|
|
---
|
|
src/proto_tcp.c | 4 ++--
|
|
src/sample.c | 23 ++++++++++++++++++++++-
|
|
src/stick_table.c | 11 ++++++++++-
|
|
3 files changed, 34 insertions(+), 4 deletions(-)
|
|
|
|
diff --git a/src/proto_tcp.c b/src/proto_tcp.c
|
|
index 9778856..72dc92b 100644
|
|
--- a/src/proto_tcp.c
|
|
+++ b/src/proto_tcp.c
|
|
@@ -1048,8 +1048,8 @@ int tcp_inspect_request(struct session *s, struct channel *req, int an_bit)
|
|
t = rule->act_prm.trk_ctr.table.t;
|
|
key = stktable_fetch_key(t, s->be, s, &s->txn, SMP_OPT_DIR_REQ | partial, rule->act_prm.trk_ctr.expr, &smp);
|
|
|
|
- if (smp.flags & SMP_F_MAY_CHANGE)
|
|
- goto missing_data;
|
|
+ if ((smp.flags & SMP_F_MAY_CHANGE) && !(partial & SMP_OPT_FINAL))
|
|
+ goto missing_data; /* key might appear later */
|
|
|
|
if (key && (ts = stktable_get_entry(t, key))) {
|
|
session_track_stkctr(&s->stkctr[tcp_trk_idx(rule->action)], t, ts);
|
|
diff --git a/src/sample.c b/src/sample.c
|
|
index 3a0f3fb..8e62640 100644
|
|
--- a/src/sample.c
|
|
+++ b/src/sample.c
|
|
@@ -896,6 +896,18 @@ out_error:
|
|
* Note: the fetch functions are required to properly set the return type. The
|
|
* conversion functions must do so too. However the cast functions do not need
|
|
* to since they're made to cast mutiple types according to what is required.
|
|
+ *
|
|
+ * The caller may indicate in <opt> if it considers the result final or not.
|
|
+ * The caller needs to check the SMP_F_MAY_CHANGE flag in p->flags to verify
|
|
+ * if the result is stable or not, according to the following table :
|
|
+ *
|
|
+ * return MAY_CHANGE FINAL Meaning for the sample
|
|
+ * NULL 0 * Not present and will never be (eg: header)
|
|
+ * NULL 1 0 Not present yet, could change (eg: POST param)
|
|
+ * NULL 1 1 Not present yet, will not change anymore
|
|
+ * smp 0 * Present and will not change (eg: header)
|
|
+ * smp 1 0 Present, may change (eg: request length)
|
|
+ * smp 1 1 Present, last known value (eg: request length)
|
|
*/
|
|
struct sample *sample_process(struct proxy *px, struct session *l4, void *l7,
|
|
unsigned int opt,
|
|
@@ -1153,7 +1165,16 @@ int smp_resolve_args(struct proxy *p)
|
|
* and <opt> does not contain SMP_OPT_FINAL, then the sample is returned as-is
|
|
* with its SMP_F_MAY_CHANGE flag so that the caller can check it and decide to
|
|
* take actions (eg: wait longer). If a sample could not be found or could not
|
|
- * be converted, NULL is returned.
|
|
+ * be converted, NULL is returned. The caller MUST NOT use the sample if the
|
|
+ * SMP_F_MAY_CHANGE flag is present, as it is used only as a hint that there is
|
|
+ * still hope to get it after waiting longer, and is not converted to string.
|
|
+ * The possible output combinations are the following :
|
|
+ *
|
|
+ * return MAY_CHANGE FINAL Meaning for the sample
|
|
+ * NULL * * Not present and will never be (eg: header)
|
|
+ * smp 0 * Final value converted (eg: header)
|
|
+ * smp 1 0 Not present yet, may appear later (eg: header)
|
|
+ * smp 1 1 never happens (either flag is cleared on output)
|
|
*/
|
|
struct sample *sample_fetch_string(struct proxy *px, struct session *l4, void *l7,
|
|
unsigned int opt, struct sample_expr *expr)
|
|
diff --git a/src/stick_table.c b/src/stick_table.c
|
|
index a708d3c..d39b4ff 100644
|
|
--- a/src/stick_table.c
|
|
+++ b/src/stick_table.c
|
|
@@ -603,7 +603,16 @@ static sample_to_key_fct sample_to_key[SMP_TYPES][STKTABLE_TYPES] = {
|
|
* no key could be extracted, or a pointer to the converted result stored in
|
|
* static_table_key in format <table_type>. If <smp> is not NULL, it will be reset
|
|
* and its flags will be initialized so that the caller gets a copy of the input
|
|
- * sample, and knows why it was not accepted (eg: SMP_F_MAY_CHANGE is present).
|
|
+ * sample, and knows why it was not accepted (eg: SMP_F_MAY_CHANGE is present
|
|
+ * without SMP_OPT_FINAL). The output will be usable like this :
|
|
+ *
|
|
+ * return MAY_CHANGE FINAL Meaning for the sample
|
|
+ * NULL 0 * Not present and will never be (eg: header)
|
|
+ * NULL 1 0 Not present or unstable, could change (eg: req_len)
|
|
+ * NULL 1 1 Not present, will not change anymore
|
|
+ * smp 0 * Present and will not change (eg: header)
|
|
+ * smp 1 0 not possible
|
|
+ * smp 1 1 Present, last known value (eg: request length)
|
|
*/
|
|
struct stktable_key *stktable_fetch_key(struct stktable *t, struct proxy *px, struct session *l4, void *l7,
|
|
unsigned int opt, struct sample_expr *expr, struct sample *smp)
|
|
--
|
|
1.8.5.5
|
|
|