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[Qemu-devel] [PULL 2/6] nbd/server: refactor negotiation functions param
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From: |
Eric Blake |
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Subject: |
[Qemu-devel] [PULL 2/6] nbd/server: refactor negotiation functions parameters |
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Date: |
Wed, 17 Jan 2018 20:26:21 -0600 |
From: Vladimir Sementsov-Ogievskiy <address@hidden>
Instead of passing currently negotiating option and its length to
many of negotiation functions let's just store them on NBDClient
struct to be state-variables of negotiation phase.
This unifies semantics of negotiation functions and allows
tracking changes of remaining option length in future patches.
Asssert that optlen is back to 0 after negotiation (including
old-style connections which don't negotiate), although we need
more patches before we can assert optlen is 0 between options
during negotiation.
Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
Message-Id: <address@hidden>
[eblake: rebase, commit message tweak, assert !optlen after
negotiation completes]
Signed-off-by: Eric Blake <address@hidden>
---
nbd/server.c | 168 +++++++++++++++++++++++++++++------------------------------
1 file changed, 84 insertions(+), 84 deletions(-)
diff --git a/nbd/server.c b/nbd/server.c
index 5ba12f3c0b3..b9efdcc605d 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -102,9 +102,11 @@ struct NBDClient {
bool closing;
bool structured_reply;
-};
-/* That's all folks */
+ uint32_t opt; /* Current option being negotiated */
+ uint32_t optlen; /* remaining length of data in ioc for the option being
+ negotiated now */
+};
static void nbd_client_receive_next_request(NBDClient *client);
@@ -137,10 +139,12 @@ static void nbd_client_receive_next_request(NBDClient
*client);
/* Send a reply header, including length, but no payload.
* Return -errno on error, 0 on success. */
-static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type,
- uint32_t opt, uint32_t len, Error **errp)
+static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type,
+ uint32_t len, Error **errp)
{
uint64_t magic;
+ QIOChannel *ioc = client->ioc;
+ uint32_t opt = client->opt;
trace_nbd_negotiate_send_rep_len(opt, nbd_opt_lookup(opt),
type, nbd_rep_lookup(type), len);
@@ -174,17 +178,17 @@ static int nbd_negotiate_send_rep_len(QIOChannel *ioc,
uint32_t type,
/* Send a reply header with default 0 length.
* Return -errno on error, 0 on success. */
-static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt,
+static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type,
Error **errp)
{
- return nbd_negotiate_send_rep_len(ioc, type, opt, 0, errp);
+ return nbd_negotiate_send_rep_len(client, type, 0, errp);
}
/* Send an error reply.
* Return -errno on error, 0 on success. */
-static int GCC_FMT_ATTR(5, 6)
-nbd_negotiate_send_rep_err(QIOChannel *ioc, uint32_t type,
- uint32_t opt, Error **errp, const char *fmt, ...)
+static int GCC_FMT_ATTR(4, 5)
+nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type,
+ Error **errp, const char *fmt, ...)
{
va_list va;
char *msg;
@@ -197,11 +201,11 @@ nbd_negotiate_send_rep_err(QIOChannel *ioc, uint32_t type,
len = strlen(msg);
assert(len < 4096);
trace_nbd_negotiate_send_rep_err(msg);
- ret = nbd_negotiate_send_rep_len(ioc, type, opt, len, errp);
+ ret = nbd_negotiate_send_rep_len(client, type, len, errp);
if (ret < 0) {
goto out;
}
- if (nbd_write(ioc, msg, len, errp) < 0) {
+ if (nbd_write(client->ioc, msg, len, errp) < 0) {
error_prepend(errp, "write failed (error message): ");
ret = -EIO;
} else {
@@ -215,21 +219,21 @@ out:
/* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
* Return -errno on error, 0 on success. */
-static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp,
+static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp,
Error **errp)
{
size_t name_len, desc_len;
uint32_t len;
const char *name = exp->name ? exp->name : "";
const char *desc = exp->description ? exp->description : "";
+ QIOChannel *ioc = client->ioc;
int ret;
trace_nbd_negotiate_send_rep_list(name, desc);
name_len = strlen(name);
desc_len = strlen(desc);
len = name_len + desc_len + sizeof(len);
- ret = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST, len,
- errp);
+ ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp);
if (ret < 0) {
return ret;
}
@@ -258,20 +262,21 @@ static int nbd_negotiate_send_rep_list(QIOChannel *ioc,
NBDExport *exp,
static int nbd_negotiate_handle_list(NBDClient *client, Error **errp)
{
NBDExport *exp;
+ assert(client->opt == NBD_OPT_LIST);
/* For each export, send a NBD_REP_SERVER reply. */
QTAILQ_FOREACH(exp, &exports, next) {
- if (nbd_negotiate_send_rep_list(client->ioc, exp, errp)) {
+ if (nbd_negotiate_send_rep_list(client, exp, errp)) {
return -EINVAL;
}
}
/* Finish with a NBD_REP_ACK. */
- return nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_LIST,
errp);
+ return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
}
/* Send a reply to NBD_OPT_EXPORT_NAME.
* Return -errno on error, 0 on success. */
-static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length,
+static int nbd_negotiate_handle_export_name(NBDClient *client,
uint16_t myflags, bool no_zeroes,
Error **errp)
{
@@ -288,15 +293,16 @@ static int nbd_negotiate_handle_export_name(NBDClient
*client, uint32_t length,
[10 .. 133] reserved (0) [unless no_zeroes]
*/
trace_nbd_negotiate_handle_export_name();
- if (length >= sizeof(name)) {
+ if (client->optlen >= sizeof(name)) {
error_setg(errp, "Bad length received");
return -EINVAL;
}
- if (nbd_read(client->ioc, name, length, errp) < 0) {
+ if (nbd_read(client->ioc, name, client->optlen, errp) < 0) {
error_prepend(errp, "read failed: ");
return -EINVAL;
}
- name[length] = '\0';
+ name[client->optlen] = '\0';
+ client->optlen = 0;
trace_nbd_negotiate_handle_export_name_request(name);
@@ -326,14 +332,14 @@ static int nbd_negotiate_handle_export_name(NBDClient
*client, uint32_t length,
/* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes.
* The buffer does NOT include the info type prefix.
* Return -errno on error, 0 if ready to send more. */
-static int nbd_negotiate_send_info(NBDClient *client, uint32_t opt,
+static int nbd_negotiate_send_info(NBDClient *client,
uint16_t info, uint32_t length, void *buf,
Error **errp)
{
int rc;
trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length);
- rc = nbd_negotiate_send_rep_len(client->ioc, NBD_REP_INFO, opt,
+ rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO,
sizeof(info) + length, errp);
if (rc < 0) {
return rc;
@@ -355,22 +361,20 @@ static int nbd_negotiate_send_info(NBDClient *client,
uint32_t opt,
* -errno transmission error occurred or @fatal was requested, errp is set
* 0 error message successfully sent to client, errp is not set
*/
-static int nbd_reject_length(NBDClient *client, uint32_t length,
- uint32_t option, bool fatal, Error **errp)
+static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp)
{
int ret;
- assert(length);
- if (nbd_drop(client->ioc, length, errp) < 0) {
+ assert(client->optlen);
+ if (nbd_drop(client->ioc, client->optlen, errp) < 0) {
return -EIO;
}
- ret = nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID,
- option, errp,
+ ret = nbd_negotiate_send_rep_err(client, NBD_REP_ERR_INVALID, errp,
"option '%s' should have zero length",
- nbd_opt_lookup(option));
+ nbd_opt_lookup(client->opt));
if (fatal && !ret) {
error_setg(errp, "option '%s' should have zero length",
- nbd_opt_lookup(option));
+ nbd_opt_lookup(client->opt));
return -EINVAL;
}
return ret;
@@ -379,8 +383,7 @@ static int nbd_reject_length(NBDClient *client, uint32_t
length,
/* Handle NBD_OPT_INFO and NBD_OPT_GO.
* Return -errno on error, 0 if ready for next option, and 1 to move
* into transmission phase. */
-static int nbd_negotiate_handle_info(NBDClient *client, uint32_t length,
- uint32_t opt, uint16_t myflags,
+static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags,
Error **errp)
{
int rc;
@@ -401,7 +404,7 @@ static int nbd_negotiate_handle_info(NBDClient *client,
uint32_t length,
2 bytes: N, number of requests (can be 0)
N * 2 bytes: N requests
*/
- if (length < sizeof(namelen) + sizeof(requests)) {
+ if (client->optlen < sizeof(namelen) + sizeof(requests)) {
msg = "overall request too short";
goto invalid;
}
@@ -409,8 +412,10 @@ static int nbd_negotiate_handle_info(NBDClient *client,
uint32_t length,
return -EIO;
}
be32_to_cpus(&namelen);
- length -= sizeof(namelen);
- if (namelen > length - sizeof(requests) || (length - namelen) % 2) {
+ client->optlen -= sizeof(namelen);
+ if (namelen > client->optlen - sizeof(requests) ||
+ (client->optlen - namelen) % 2)
+ {
msg = "name length is incorrect";
goto invalid;
}
@@ -422,16 +427,16 @@ static int nbd_negotiate_handle_info(NBDClient *client,
uint32_t length,
return -EIO;
}
name[namelen] = '\0';
- length -= namelen;
+ client->optlen -= namelen;
trace_nbd_negotiate_handle_export_name_request(name);
if (nbd_read(client->ioc, &requests, sizeof(requests), errp) < 0) {
return -EIO;
}
be16_to_cpus(&requests);
- length -= sizeof(requests);
+ client->optlen -= sizeof(requests);
trace_nbd_negotiate_handle_info_requests(requests);
- if (requests != length / sizeof(request)) {
+ if (requests != client->optlen / sizeof(request)) {
msg = "incorrect number of requests for overall length";
goto invalid;
}
@@ -440,7 +445,7 @@ static int nbd_negotiate_handle_info(NBDClient *client,
uint32_t length,
return -EIO;
}
be16_to_cpus(&request);
- length -= sizeof(request);
+ client->optlen -= sizeof(request);
trace_nbd_negotiate_handle_info_request(request,
nbd_info_lookup(request));
/* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE;
@@ -455,18 +460,18 @@ static int nbd_negotiate_handle_info(NBDClient *client,
uint32_t length,
break;
}
}
- assert(length == 0);
+ assert(client->optlen == 0);
exp = nbd_export_find(name);
if (!exp) {
- return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_UNKNOWN,
- opt, errp, "export '%s' not present",
+ return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN,
+ errp, "export '%s' not present",
name);
}
/* Don't bother sending NBD_INFO_NAME unless client requested it */
if (sendname) {
- rc = nbd_negotiate_send_info(client, opt, NBD_INFO_NAME, namelen, name,
+ rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name,
errp);
if (rc < 0) {
return rc;
@@ -478,7 +483,7 @@ static int nbd_negotiate_handle_info(NBDClient *client,
uint32_t length,
if (exp->description) {
size_t len = strlen(exp->description);
- rc = nbd_negotiate_send_info(client, opt, NBD_INFO_DESCRIPTION,
+ rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION,
len, exp->description, errp);
if (rc < 0) {
return rc;
@@ -490,7 +495,8 @@ static int nbd_negotiate_handle_info(NBDClient *client,
uint32_t length,
* whether this is OPT_INFO or OPT_GO. */
/* minimum - 1 for back-compat, or 512 if client is new enough.
* TODO: consult blk_bs(blk)->bl.request_alignment? */
- sizes[0] = (opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1;
+ sizes[0] =
+ (client->opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1;
/* preferred - Hard-code to 4096 for now.
* TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */
sizes[1] = 4096;
@@ -500,7 +506,7 @@ static int nbd_negotiate_handle_info(NBDClient *client,
uint32_t length,
cpu_to_be32s(&sizes[0]);
cpu_to_be32s(&sizes[1]);
cpu_to_be32s(&sizes[2]);
- rc = nbd_negotiate_send_info(client, opt, NBD_INFO_BLOCK_SIZE,
+ rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE,
sizeof(sizes), sizes, errp);
if (rc < 0) {
return rc;
@@ -511,7 +517,7 @@ static int nbd_negotiate_handle_info(NBDClient *client,
uint32_t length,
exp->nbdflags | myflags);
stq_be_p(buf, exp->size);
stw_be_p(buf + 8, exp->nbdflags | myflags);
- rc = nbd_negotiate_send_info(client, opt, NBD_INFO_EXPORT,
+ rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT,
sizeof(buf), buf, errp);
if (rc < 0) {
return rc;
@@ -521,21 +527,21 @@ static int nbd_negotiate_handle_info(NBDClient *client,
uint32_t length,
* request block sizes, return an error.
* TODO: consult blk_bs(blk)->request_align, and only error if it
* is not 1? */
- if (opt == NBD_OPT_INFO && !blocksize) {
- return nbd_negotiate_send_rep_err(client->ioc,
- NBD_REP_ERR_BLOCK_SIZE_REQD, opt,
+ if (client->opt == NBD_OPT_INFO && !blocksize) {
+ return nbd_negotiate_send_rep_err(client,
+ NBD_REP_ERR_BLOCK_SIZE_REQD,
errp,
"request NBD_INFO_BLOCK_SIZE to "
"use this export");
}
/* Final reply */
- rc = nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, opt, errp);
+ rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
if (rc < 0) {
return rc;
}
- if (opt == NBD_OPT_GO) {
+ if (client->opt == NBD_OPT_GO) {
client->exp = exp;
QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
nbd_export_get(client->exp);
@@ -544,10 +550,10 @@ static int nbd_negotiate_handle_info(NBDClient *client,
uint32_t length,
return rc;
invalid:
- if (nbd_drop(client->ioc, length, errp) < 0) {
+ if (nbd_drop(client->ioc, client->optlen, errp) < 0) {
return -EIO;
}
- return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID, opt,
+ return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_INVALID,
errp, "%s", msg);
}
@@ -561,11 +567,12 @@ static QIOChannel
*nbd_negotiate_handle_starttls(NBDClient *client,
QIOChannelTLS *tioc;
struct NBDTLSHandshakeData data = { 0 };
+ assert(client->opt == NBD_OPT_STARTTLS);
+
trace_nbd_negotiate_handle_starttls();
ioc = client->ioc;
- if (nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK,
- NBD_OPT_STARTTLS, errp) < 0) {
+ if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) {
return NULL;
}
@@ -670,12 +677,14 @@ static int nbd_negotiate_options(NBDClient *client,
uint16_t myflags,
return -EINVAL;
}
option = be32_to_cpu(option);
+ client->opt = option;
if (nbd_read(client->ioc, &length, sizeof(length), errp) < 0) {
error_prepend(errp, "read failed: ");
return -EINVAL;
}
length = be32_to_cpu(length);
+ client->optlen = length;
if (length > NBD_MAX_BUFFER_SIZE) {
error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
@@ -697,8 +706,7 @@ static int nbd_negotiate_options(NBDClient *client,
uint16_t myflags,
if (length) {
/* Unconditionally drop the connection if the client
* can't start a TLS negotiation correctly */
- return nbd_reject_length(client, length, option, true,
- errp);
+ return nbd_reject_length(client, true, errp);
}
tioc = nbd_negotiate_handle_starttls(client, errp);
if (!tioc) {
@@ -719,9 +727,8 @@ static int nbd_negotiate_options(NBDClient *client,
uint16_t myflags,
if (nbd_drop(client->ioc, length, errp) < 0) {
return -EIO;
}
- ret = nbd_negotiate_send_rep_err(client->ioc,
- NBD_REP_ERR_TLS_REQD,
- option, errp,
+ ret = nbd_negotiate_send_rep_err(client,
+ NBD_REP_ERR_TLS_REQD, errp,
"Option 0x%" PRIx32
"not permitted before TLS",
option);
@@ -737,8 +744,7 @@ static int nbd_negotiate_options(NBDClient *client,
uint16_t myflags,
switch (option) {
case NBD_OPT_LIST:
if (length) {
- ret = nbd_reject_length(client, length, option, false,
- errp);
+ ret = nbd_reject_length(client, false, errp);
} else {
ret = nbd_negotiate_handle_list(client, errp);
}
@@ -748,18 +754,17 @@ static int nbd_negotiate_options(NBDClient *client,
uint16_t myflags,
/* NBD spec says we must try to reply before
* disconnecting, but that we must also tolerate
* guests that don't wait for our reply. */
- nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, option, NULL);
+ nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL);
return 1;
case NBD_OPT_EXPORT_NAME:
- return nbd_negotiate_handle_export_name(client, length,
+ return nbd_negotiate_handle_export_name(client,
myflags, no_zeroes,
errp);
case NBD_OPT_INFO:
case NBD_OPT_GO:
- ret = nbd_negotiate_handle_info(client, length, option,
- myflags, errp);
+ ret = nbd_negotiate_handle_info(client, myflags, errp);
if (ret == 1) {
assert(option == NBD_OPT_GO);
return 0;
@@ -768,32 +773,27 @@ static int nbd_negotiate_options(NBDClient *client,
uint16_t myflags,
case NBD_OPT_STARTTLS:
if (length) {
- ret = nbd_reject_length(client, length, option, false,
- errp);
+ ret = nbd_reject_length(client, false, errp);
} else if (client->tlscreds) {
- ret = nbd_negotiate_send_rep_err(client->ioc,
- NBD_REP_ERR_INVALID,
- option, errp,
+ ret = nbd_negotiate_send_rep_err(client,
+ NBD_REP_ERR_INVALID, errp,
"TLS already enabled");
} else {
- ret = nbd_negotiate_send_rep_err(client->ioc,
- NBD_REP_ERR_POLICY,
- option, errp,
+ ret = nbd_negotiate_send_rep_err(client,
+ NBD_REP_ERR_POLICY, errp,
"TLS not configured");
}
break;
case NBD_OPT_STRUCTURED_REPLY:
if (length) {
- ret = nbd_reject_length(client, length, option, false,
- errp);
+ ret = nbd_reject_length(client, false, errp);
} else if (client->structured_reply) {
ret = nbd_negotiate_send_rep_err(
- client->ioc, NBD_REP_ERR_INVALID, option, errp,
+ client, NBD_REP_ERR_INVALID, errp,
"structured reply already negotiated");
} else {
- ret = nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK,
- option, errp);
+ ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
client->structured_reply = true;
myflags |= NBD_FLAG_SEND_DF;
}
@@ -803,9 +803,8 @@ static int nbd_negotiate_options(NBDClient *client,
uint16_t myflags,
if (nbd_drop(client->ioc, length, errp) < 0) {
return -EIO;
}
- ret = nbd_negotiate_send_rep_err(client->ioc,
- NBD_REP_ERR_UNSUP,
- option, errp,
+ ret = nbd_negotiate_send_rep_err(client,
+ NBD_REP_ERR_UNSUP, errp,
"Unsupported option 0x%"
PRIx32 " (%s)", option,
nbd_opt_lookup(option));
@@ -818,7 +817,7 @@ static int nbd_negotiate_options(NBDClient *client,
uint16_t myflags,
*/
switch (option) {
case NBD_OPT_EXPORT_NAME:
- return nbd_negotiate_handle_export_name(client, length,
+ return nbd_negotiate_handle_export_name(client,
myflags, no_zeroes,
errp);
@@ -898,6 +897,7 @@ static coroutine_fn int nbd_negotiate(NBDClient *client,
Error **errp)
}
}
+ assert(!client->optlen);
trace_nbd_negotiate_success();
return 0;
--
2.14.3
- [Qemu-devel] [PULL 0/6] NBD patches through 17 Jan, Eric Blake, 2018/01/17
- [Qemu-devel] [PULL 3/6] nbd/server: Better error for NBD_OPT_EXPORT_NAME failure, Eric Blake, 2018/01/17
- [Qemu-devel] [PULL 1/6] nbd/server: Hoist nbd_reject_length() earlier, Eric Blake, 2018/01/17
- [Qemu-devel] [PULL 4/6] nbd/server: Add va_list form of nbd_negotiate_send_rep_err(), Eric Blake, 2018/01/17
- [Qemu-devel] [PULL 2/6] nbd/server: refactor negotiation functions parameters,
Eric Blake <=
- [Qemu-devel] [PULL 6/6] nbd/server: structurize option reply sending, Eric Blake, 2018/01/17
- [Qemu-devel] [PULL 5/6] nbd/server: Add helper functions for parsing option payload, Eric Blake, 2018/01/17
- Re: [Qemu-devel] [PULL 0/6] NBD patches through 17 Jan, Peter Maydell, 2018/01/18