BUG/MAJOR: fix regression on content-based hashing and http-send-name-header
The recent split between the buffers and HTTP messages in 1.5-dev9 caused
a major trouble : in the past, we used to keep a pointer to HTTP data in the
buffer struct itself, which was the cause of most of the pain we had to deal
with buffers.
Now the two are split but we lost the information about the beginning of
the HTTP message once it's being forwarded. While it seems normal, it happens
that several parts of the code currently rely on this ability to inspect a
buffer containing old contents :
- balance uri
- balance url_param
- balance url_param check_post
- balance hdr()
- balance rdp-cookie()
- http-send-name-header
All these happen after the data are scheduled for being forwarded, which
also causes a server to be selected. So for a long time we've been relying
on supposedly sent data that we still had a pointer to.
Now that we don't have such a pointer anymore, we only have one possibility :
when we need to inspect such data, we have to rewind the buffer so that ->p
points to where it previously was. We're lucky, no data can leave the buffer
before it's being connecting outside, and since no inspection can begin until
it's empty, we know that the skipped data are exactly ->o. So we rewind the
buffer by ->o to get headers and advance it back by the same amount.
Proceeding this way is particularly important when dealing with chunked-
encoded requests, because the ->som and ->sov fields may be reused by the
chunk parser before the connection attempt is made, so we cannot rely on
them.
Also, we need to be able to come back after retries and redispatches, which
might change the size of the request if http-send-name-header is set. All of
this is accounted for by the output queue so in the end it does not look like
a bad solution.
No backport is needed.
diff --git a/src/backend.c b/src/backend.c
index 3f30bea..b8bf7dd 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -30,6 +30,7 @@
#include <proto/acl.h>
#include <proto/arg.h>
#include <proto/backend.h>
+#include <proto/buffers.h>
#include <proto/frontend.h>
#include <proto/lb_chash.h>
#include <proto/lb_fas.h>
@@ -256,11 +257,11 @@
struct proxy *px = s->be;
unsigned int plen = px->url_param_len;
unsigned long len = msg->body_len;
- const char *params = req->p + msg->sov;
+ const char *params = b_ptr(req, (int)(msg->sov - req->o));
const char *p = params;
- if (len > req->i - (msg->sov - msg->som))
- len = req->i - (msg->sov - msg->som);
+ if (len > buffer_len(req) - (msg->sov - msg->som))
+ len = buffer_len(req) - (msg->sov - msg->som);
if (len == 0)
return NULL;
@@ -342,7 +343,7 @@
ctx.idx = 0;
/* if the message is chunked, we skip the chunk size, but use the value as len */
- http_find_header2(px->hh_name, plen, s->req->p + msg->sol, &txn->hdr_idx, &ctx);
+ http_find_header2(px->hh_name, plen, b_ptr(s->req, (int)(msg->sol - s->req->o)), &txn->hdr_idx, &ctx);
/* if the header is not found or empty, let's fallback to round robin */
if (!ctx.idx || !ctx.vlen)
@@ -405,6 +406,7 @@
int ret;
struct sample smp;
struct arg args[2];
+ int rewind;
/* tot_weight appears to mean srv_count */
if (px->lbprm.tot_weight == 0)
@@ -417,9 +419,13 @@
args[0].data.str.len = px->hh_len;
args[1].type = ARGT_STOP;
+ b_rew(s->req, rewind = s->req->o);
+
ret = smp_fetch_rdp_cookie(px, s, NULL, SMP_OPT_DIR_REQ|SMP_OPT_FINAL, args, &smp);
len = smp.data.str.len;
+ b_adv(s->req, rewind);
+
if (ret == 0 || (smp.flags & SMP_F_MAY_CHANGE) || len == 0)
return NULL;
@@ -563,7 +569,7 @@
if (s->txn.req.msg_state < HTTP_MSG_BODY)
break;
srv = get_server_uh(s->be,
- s->req->p + s->txn.req.sol + s->txn.req.sl.rq.u,
+ b_ptr(s->req, (int)(s->txn.req.sol + s->txn.req.sl.rq.u - s->req->o)),
s->txn.req.sl.rq.u_l);
break;
@@ -573,7 +579,7 @@
break;
srv = get_server_ph(s->be,
- s->req->p + s->txn.req.sol + s->txn.req.sl.rq.u,
+ b_ptr(s->req, (int)(s->txn.req.sol + s->txn.req.sl.rq.u - s->req->o)),
s->txn.req.sl.rq.u_l);
if (!srv && s->txn.meth == HTTP_METH_POST)
@@ -892,17 +898,20 @@
if (srv->bind_hdr_occ) {
char *vptr;
int vlen;
+ int rewind;
/* bind to the IP in a header */
((struct sockaddr_in *)&s->req->cons->addr.from)->sin_family = AF_INET;
((struct sockaddr_in *)&s->req->cons->addr.from)->sin_port = 0;
((struct sockaddr_in *)&s->req->cons->addr.from)->sin_addr.s_addr = 0;
+ b_rew(s->req, rewind = s->req->o);
if (http_get_hdr(&s->txn.req, srv->bind_hdr_name, srv->bind_hdr_len,
&s->txn.hdr_idx, srv->bind_hdr_occ, NULL, &vptr, &vlen)) {
((struct sockaddr_in *)&s->req->cons->addr.from)->sin_addr.s_addr =
htonl(inetaddr_host_lim(vptr, vptr + vlen));
}
+ b_adv(s->req, rewind);
}
break;
default:
@@ -923,17 +932,20 @@
if (s->be->bind_hdr_occ) {
char *vptr;
int vlen;
+ int rewind;
/* bind to the IP in a header */
((struct sockaddr_in *)&s->req->cons->addr.from)->sin_family = AF_INET;
((struct sockaddr_in *)&s->req->cons->addr.from)->sin_port = 0;
((struct sockaddr_in *)&s->req->cons->addr.from)->sin_addr.s_addr = 0;
+ b_rew(s->req, rewind = s->req->o);
if (http_get_hdr(&s->txn.req, s->be->bind_hdr_name, s->be->bind_hdr_len,
&s->txn.hdr_idx, s->be->bind_hdr_occ, NULL, &vptr, &vlen)) {
((struct sockaddr_in *)&s->req->cons->addr.from)->sin_addr.s_addr =
htonl(inetaddr_host_lim(vptr, vptr + vlen));
}
+ b_adv(s->req, rewind);
}
break;
default: