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588 lines (469 loc) · 14.6 KB
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/*
* twemproxy - A fast and lightweight proxy for memcached protocol.
* Copyright (C) 2011 Twitter, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <nc_core.h>
#include <nc_server.h>
#include <nc_event.h>
struct msg *
req_get(struct conn *conn)
{
struct msg *msg;
ASSERT(conn->client && !conn->proxy);
msg = msg_get(conn, true, conn->redis);
if (msg == NULL) {
conn->err = errno;
}
return msg;
}
void
req_put(struct msg *msg)
{
struct msg *pmsg; /* peer message (response) */
ASSERT(msg->request);
pmsg = msg->peer;
if (pmsg != NULL) {
ASSERT(!pmsg->request && pmsg->peer == msg);
msg->peer = NULL;
pmsg->peer = NULL;
rsp_put(pmsg);
}
msg_tmo_delete(msg);
msg_put(msg);
}
/*
* Return true if request is done, false otherwise
*
* A request is done, if we received response for the given request.
* A request vector is done if we received responses for all its
* fragments.
*/
bool
req_done(struct conn *conn, struct msg *msg)
{
struct msg *cmsg, *pmsg; /* current and previous message */
uint64_t id; /* fragment id */
uint32_t nfragment; /* # fragment */
ASSERT(conn->client && !conn->proxy);
ASSERT(msg->request);
if (!msg->done) {
return false;
}
id = msg->frag_id;
if (id == 0) {
return true;
}
if (msg->fdone) {
/* request has already been marked as done */
return true;
}
/* check all fragments of the given request vector are done */
for (pmsg = msg, cmsg = TAILQ_PREV(msg, msg_tqh, c_tqe);
cmsg != NULL && cmsg->frag_id == id;
pmsg = cmsg, cmsg = TAILQ_PREV(cmsg, msg_tqh, c_tqe)) {
if (!cmsg->done) {
return false;
}
}
for (pmsg = msg, cmsg = TAILQ_NEXT(msg, c_tqe);
cmsg != NULL && cmsg->frag_id == id;
pmsg = cmsg, cmsg = TAILQ_NEXT(cmsg, c_tqe)) {
if (!cmsg->done) {
return false;
}
}
if (!pmsg->last_fragment) {
return false;
}
/*
* At this point, all the fragments including the last fragment have
* been received.
*
* Mark all fragments of the given request vector to be done to speed up
* future req_done calls for any of fragments of this request
*/
msg->fdone = 1;
nfragment = 1;
for (pmsg = msg, cmsg = TAILQ_PREV(msg, msg_tqh, c_tqe);
cmsg != NULL && cmsg->frag_id == id;
pmsg = cmsg, cmsg = TAILQ_PREV(cmsg, msg_tqh, c_tqe)) {
cmsg->fdone = 1;
nfragment++;
}
for (pmsg = msg, cmsg = TAILQ_NEXT(msg, c_tqe);
cmsg != NULL && cmsg->frag_id == id;
pmsg = cmsg, cmsg = TAILQ_NEXT(cmsg, c_tqe)) {
cmsg->fdone = 1;
nfragment++;
}
ASSERT(msg->frag_owner->nfrag == nfragment);
msg->post_coalesce(msg->frag_owner);
log_debug(LOG_DEBUG, "req from c %d with fid %"PRIu64" and %"PRIu32" "
"fragments is done", conn->sd, id, nfragment);
return true;
}
/*
* Return true if request is in error, false otherwise
*
* A request is in error, if there was an error in receiving response for the
* given request. A multiget request is in error if there was an error in
* receiving response for any its fragments.
*/
bool
req_error(struct conn *conn, struct msg *msg)
{
struct msg *cmsg; /* current message */
uint64_t id;
uint32_t nfragment;
ASSERT(msg->request && req_done(conn, msg));
if (msg->error) {
return true;
}
id = msg->frag_id;
if (id == 0) {
return false;
}
if (msg->ferror) {
/* request has already been marked to be in error */
return true;
}
/* check if any of the fragments of the given request are in error */
for (cmsg = TAILQ_PREV(msg, msg_tqh, c_tqe);
cmsg != NULL && cmsg->frag_id == id;
cmsg = TAILQ_PREV(cmsg, msg_tqh, c_tqe)) {
if (cmsg->error) {
goto ferror;
}
}
for (cmsg = TAILQ_NEXT(msg, c_tqe);
cmsg != NULL && cmsg->frag_id == id;
cmsg = TAILQ_NEXT(cmsg, c_tqe)) {
if (cmsg->error) {
goto ferror;
}
}
return false;
ferror:
/*
* Mark all fragments of the given request to be in error to speed up
* future req_error calls for any of fragments of this request
*/
msg->ferror = 1;
nfragment = 1;
for (cmsg = TAILQ_PREV(msg, msg_tqh, c_tqe);
cmsg != NULL && cmsg->frag_id == id;
cmsg = TAILQ_PREV(cmsg, msg_tqh, c_tqe)) {
cmsg->ferror = 1;
nfragment++;
}
for (cmsg = TAILQ_NEXT(msg, c_tqe);
cmsg != NULL && cmsg->frag_id == id;
cmsg = TAILQ_NEXT(cmsg, c_tqe)) {
cmsg->ferror = 1;
nfragment++;
}
log_debug(LOG_DEBUG, "req from c %d with fid %"PRIu64" and %"PRIu32" "
"fragments is in error", conn->sd, id, nfragment);
return true;
}
void
req_server_enqueue_imsgq(struct context *ctx, struct conn *conn, struct msg *msg)
{
ASSERT(msg->request);
ASSERT(!conn->client && !conn->proxy);
/*
* timeout clock starts ticking the instant the message is enqueued into
* the server in_q; the clock continues to tick until it either expires
* or the message is dequeued from the server out_q
*
* noreply request are free from timeouts because client is not intrested
* in the reponse anyway!
*/
if (!msg->noreply) {
msg_tmo_insert(msg, conn);
}
TAILQ_INSERT_TAIL(&conn->imsg_q, msg, s_tqe);
stats_server_incr(ctx, conn->owner, in_queue);
stats_server_incr_by(ctx, conn->owner, in_queue_bytes, msg->mlen);
}
void
req_server_dequeue_imsgq(struct context *ctx, struct conn *conn, struct msg *msg)
{
ASSERT(msg->request);
ASSERT(!conn->client && !conn->proxy);
TAILQ_REMOVE(&conn->imsg_q, msg, s_tqe);
stats_server_decr(ctx, conn->owner, in_queue);
stats_server_decr_by(ctx, conn->owner, in_queue_bytes, msg->mlen);
}
void
req_client_enqueue_omsgq(struct context *ctx, struct conn *conn, struct msg *msg)
{
ASSERT(msg->request);
ASSERT(conn->client && !conn->proxy);
TAILQ_INSERT_TAIL(&conn->omsg_q, msg, c_tqe);
}
void
req_server_enqueue_omsgq(struct context *ctx, struct conn *conn, struct msg *msg)
{
ASSERT(msg->request);
ASSERT(!conn->client && !conn->proxy);
TAILQ_INSERT_TAIL(&conn->omsg_q, msg, s_tqe);
stats_server_incr(ctx, conn->owner, out_queue);
stats_server_incr_by(ctx, conn->owner, out_queue_bytes, msg->mlen);
}
void
req_client_dequeue_omsgq(struct context *ctx, struct conn *conn, struct msg *msg)
{
ASSERT(msg->request);
ASSERT(conn->client && !conn->proxy);
TAILQ_REMOVE(&conn->omsg_q, msg, c_tqe);
}
void
req_server_dequeue_omsgq(struct context *ctx, struct conn *conn, struct msg *msg)
{
ASSERT(msg->request);
ASSERT(!conn->client && !conn->proxy);
msg_tmo_delete(msg);
TAILQ_REMOVE(&conn->omsg_q, msg, s_tqe);
stats_server_decr(ctx, conn->owner, out_queue);
stats_server_decr_by(ctx, conn->owner, out_queue_bytes, msg->mlen);
}
struct msg *
req_recv_next(struct context *ctx, struct conn *conn, bool alloc)
{
struct msg *msg;
ASSERT(conn->client && !conn->proxy);
if (conn->eof) {
msg = conn->rmsg;
/* client sent eof before sending the entire request */
if (msg != NULL) {
conn->rmsg = NULL;
ASSERT(msg->peer == NULL);
ASSERT(msg->request && !msg->done);
log_error("eof c %d discarding incomplete req %"PRIu64" len "
"%"PRIu32"", conn->sd, msg->id, msg->mlen);
req_put(msg);
}
/*
* TCP half-close enables the client to terminate its half of the
* connection (i.e. the client no longer sends data), but it still
* is able to receive data from the proxy. The proxy closes its
* half (by sending the second FIN) when the client has no
* outstanding requests
*/
if (!conn->active(conn)) {
conn->done = 1;
log_debug(LOG_INFO, "c %d is done", conn->sd);
}
return NULL;
}
msg = conn->rmsg;
if (msg != NULL) {
ASSERT(msg->request);
return msg;
}
if (!alloc) {
return NULL;
}
msg = req_get(conn);
if (msg != NULL) {
conn->rmsg = msg;
}
return msg;
}
static bool
req_filter(struct context *ctx, struct conn *conn, struct msg *msg)
{
ASSERT(conn->client && !conn->proxy);
if (msg_empty(msg)) {
ASSERT(conn->rmsg == NULL);
log_debug(LOG_VERB, "filter empty req %"PRIu64" from c %d", msg->id,
conn->sd);
req_put(msg);
return true;
}
/*
* Handle "quit\r\n", which is the protocol way of doing a
* passive close
*/
if (msg->quit) {
ASSERT(conn->rmsg == NULL);
log_debug(LOG_INFO, "filter quit req %"PRIu64" from c %d", msg->id,
conn->sd);
conn->eof = 1;
conn->recv_ready = 0;
req_put(msg);
return true;
}
return false;
}
static void
req_forward_error(struct context *ctx, struct conn *conn, struct msg *msg)
{
rstatus_t status;
ASSERT(conn->client && !conn->proxy);
log_debug(LOG_INFO, "forward req %"PRIu64" len %"PRIu32" type %d from "
"c %d failed: %s", msg->id, msg->mlen, msg->type, conn->sd,
strerror(errno));
msg->done = 1;
msg->error = 1;
msg->err = errno;
/* noreply request don't expect any response */
if (msg->noreply) {
req_put(msg);
return;
}
if (req_done(conn, TAILQ_FIRST(&conn->omsg_q))) {
status = event_add_out(ctx->ep, conn);
if (status != NC_OK) {
conn->err = errno;
}
}
}
static void
req_forward_stats(struct context *ctx, struct server *server, struct msg *msg)
{
ASSERT(msg->request);
stats_server_incr(ctx, server, requests);
stats_server_incr_by(ctx, server, request_bytes, msg->mlen);
}
static void
req_forward(struct context *ctx, struct conn *c_conn, struct msg *msg)
{
rstatus_t status;
struct conn *s_conn;
struct server_pool *pool;
uint8_t *key;
uint32_t keylen;
ASSERT(c_conn->client && !c_conn->proxy);
/* enqueue message (request) into client outq, if response is expected */
if (!msg->noreply) {
c_conn->enqueue_outq(ctx, c_conn, msg);
}
pool = c_conn->owner;
key = NULL;
keylen = 0;
/*
* If hash_tag: is configured for this server pool, we use the part of
* the key within the hash tag as an input to the distributor. Otherwise
* we use the full key
*/
if (!string_empty(&pool->hash_tag)) {
struct string *tag = &pool->hash_tag;
uint8_t *tag_start, *tag_end;
tag_start = nc_strchr(msg->key_start, msg->key_end, tag->data[0]);
if (tag_start != NULL) {
tag_end = nc_strchr(tag_start + 1, msg->key_end, tag->data[1]);
if (tag_end != NULL) {
key = tag_start + 1;
keylen = (uint32_t)(tag_end - key);
}
}
}
if (keylen == 0) {
key = msg->key_start;
keylen = (uint32_t)(msg->key_end - msg->key_start);
}
s_conn = server_pool_conn(ctx, c_conn->owner, key, keylen);
if (s_conn == NULL) {
req_forward_error(ctx, c_conn, msg);
return;
}
ASSERT(!s_conn->client && !s_conn->proxy);
/* enqueue the message (request) into server inq */
if (TAILQ_EMPTY(&s_conn->imsg_q)) {
status = event_add_out(ctx->ep, s_conn);
if (status != NC_OK) {
req_forward_error(ctx, c_conn, msg);
s_conn->err = errno;
return;
}
}
s_conn->enqueue_inq(ctx, s_conn, msg);
req_forward_stats(ctx, s_conn->owner, msg);
log_debug(LOG_VERB, "forward from c %d to s %d req %"PRIu64" len %"PRIu32
" type %d with key '%.*s'", c_conn->sd, s_conn->sd, msg->id,
msg->mlen, msg->type, keylen, key);
}
void
req_recv_done(struct context *ctx, struct conn *conn, struct msg *msg,
struct msg *nmsg)
{
ASSERT(conn->client && !conn->proxy);
ASSERT(msg->request);
ASSERT(msg->owner == conn);
ASSERT(conn->rmsg == msg);
ASSERT(nmsg == NULL || nmsg->request);
/* enqueue next message (request), if any */
conn->rmsg = nmsg;
if (req_filter(ctx, conn, msg)) {
return;
}
req_forward(ctx, conn, msg);
}
struct msg *
req_send_next(struct context *ctx, struct conn *conn)
{
rstatus_t status;
struct msg *msg, *nmsg; /* current and next message */
ASSERT(!conn->client && !conn->proxy);
if (conn->connecting) {
server_connected(ctx, conn);
}
nmsg = TAILQ_FIRST(&conn->imsg_q);
if (nmsg == NULL) {
/* nothing to send as the server inq is empty */
status = event_del_out(ctx->ep, conn);
if (status != NC_OK) {
conn->err = errno;
}
return NULL;
}
msg = conn->smsg;
if (msg != NULL) {
ASSERT(msg->request && !msg->done);
nmsg = TAILQ_NEXT(msg, s_tqe);
}
conn->smsg = nmsg;
if (nmsg == NULL) {
return NULL;
}
ASSERT(nmsg->request && !nmsg->done);
log_debug(LOG_VVERB, "send next req %"PRIu64" len %"PRIu32" type %d on "
"s %d", nmsg->id, nmsg->mlen, nmsg->type, conn->sd);
return nmsg;
}
void
req_send_done(struct context *ctx, struct conn *conn, struct msg *msg)
{
ASSERT(!conn->client && !conn->proxy);
ASSERT(msg != NULL && conn->smsg == NULL);
ASSERT(msg->request && !msg->done);
ASSERT(msg->owner != conn);
log_debug(LOG_VVERB, "send done req %"PRIu64" len %"PRIu32" type %d on "
"s %d", msg->id, msg->mlen, msg->type, conn->sd);
/* dequeue the message (request) from server inq */
conn->dequeue_inq(ctx, conn, msg);
/*
* noreply request instructs the server not to send any response. So,
* enqueue message (request) in server outq, if response is expected.
* Otherwise, free the noreply request
*/
if (!msg->noreply) {
conn->enqueue_outq(ctx, conn, msg);
} else {
req_put(msg);
}
}