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Re: [Qemu-devel] [PATCH 1/4] Use getaddrinfo for migration
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH 1/4] Use getaddrinfo for migration |
Date: |
Fri, 02 Mar 2012 11:28:36 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:10.0.1) Gecko/20120209 Thunderbird/10.0.1 |
Am 02.03.2012 04:33, schrieb Amos Kong:
> On 24/02/12 17:08, Kevin Wolf wrote:
>> Am 10.02.2012 07:27, schrieb Amos Kong:
>>> This allows us to use ipv4/ipv6 for migration addresses.
>>> Once there, it also uses /etc/services names (it came free).
>>>
>>> Signed-off-by: Juan Quintela<address@hidden>
>>> Signed-off-by: Amos Kong<address@hidden>
>>> ---
>>> migration-tcp.c | 60 ++++++++-----------------------
>>> net.c | 108
>>> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>> qemu_socket.h | 3 ++
>>> 3 files changed, 127 insertions(+), 44 deletions(-)
>>
>> This patch is making too many changes at once:
>>
>> 1. Move code around
>> 2. Remove duplicated code between client and server
>> 3. Replace parse_host_port() with an open-coded version
>
>> 4. Modify the open-coded parse_host_port() to use getaddrinfo instead of
>> inet_aton/gethostbyname (Why can't we just change parse_host_port? Are
>> there valid reasons to use the old implementation? Which?)
>
> tcp_common_start() needs to use the address list which is got by
> getaddrinfo(),
>
> But I agree with verifying host/port by getaddrinfo() in parse_host_port.
The new parse_host_port() could return an address list. If it's the
right thing to use it here, it's probably right to use it in all other
places as well.
>> This makes it rather hard to review.
>>
>>> diff --git a/migration-tcp.c b/migration-tcp.c
>>> index 35a5781..644bb8f 100644
>>> --- a/migration-tcp.c
>>> +++ b/migration-tcp.c
>>> @@ -81,43 +81,27 @@ static void tcp_wait_for_connect(void *opaque)
>>>
>>> int tcp_start_outgoing_migration(MigrationState *s, const char *host_port)
>>> {
>>> - struct sockaddr_in addr;
>>> int ret;
>>> -
>>> - ret = parse_host_port(&addr, host_port);
>>> - if (ret< 0) {
>>> - return ret;
>>> - }
>>> + int fd;
>>>
>>> s->get_error = socket_errno;
>>> s->write = socket_write;
>>> s->close = tcp_close;
>>>
>>> - s->fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
>>> - if (s->fd == -1) {
>>> - DPRINTF("Unable to open socket");
>>> - return -socket_error();
>>> - }
>>> -
>>> - socket_set_nonblock(s->fd);
>>> -
>>> - do {
>>> - ret = connect(s->fd, (struct sockaddr *)&addr, sizeof(addr));
>>> - if (ret == -1) {
>>> - ret = -socket_error();
>>> - }
>>> - if (ret == -EINPROGRESS || ret == -EWOULDBLOCK) {
>>> - qemu_set_fd_handler2(s->fd, NULL, NULL, tcp_wait_for_connect,
>>> s);
>>> - return 0;
>>> - }
>>> - } while (ret == -EINTR);
>>> -
>>> - if (ret< 0) {
>>> + ret = tcp_client_start(host_port,&fd);
>>> + s->fd = fd;
>>> + if (ret == -EINPROGRESS || ret == -EWOULDBLOCK) {
>>> + DPRINTF("connect in progress");
>>> + qemu_set_fd_handler2(s->fd, NULL, NULL, tcp_wait_for_connect, s);
>>> + } else if (ret< 0) {
>>> DPRINTF("connect failed\n");
>>> - migrate_fd_error(s);
>>> + if (ret != -EINVAL) {
>>> + migrate_fd_error(s);
>>> + }
>>
>> This looks odd. It is probably needed to keep the old behaviour where a
>> failed parse_host_port() wouldn't call migrate_fd_error(). Is this
>> really required? Maybe I'm missing something, but the caller can't know
>> which failure case we had and if migrate_fd_error() has been called.
>
> getaddrinfo() is used in tcp_common_start(), -EINVAL will be returned
> when getaddrinfo() doesn't return 0.
This is an implementation detail of tcp_common_start(). What does
-EINVAL mean at the tcp_client_start() level? Should it be documented
with a comment?
Why must migrate_fd_error() not be called when getaddrinfo() failed?
>>> return ret;
>>> + } else {
>>> + migrate_fd_connect(s);
>>> }
>>> - migrate_fd_connect(s);
>>> return 0;
>>> }
>>>
>>> @@ -157,28 +141,16 @@ out2:
>>>
>>> int tcp_start_incoming_migration(const char *host_port)
>>> {
>>> - struct sockaddr_in addr;
>>> - int val;
>>> + int ret;
>>> int s;
>>>
>>> DPRINTF("Attempting to start an incoming migration\n");
>>>
>>> - if (parse_host_port(&addr, host_port)< 0) {
>>> - fprintf(stderr, "invalid host/port combination: %s\n", host_port);
>>> - return -EINVAL;
>>> - }
>>> -
>>> - s = qemu_socket(PF_INET, SOCK_STREAM, 0);
>>> - if (s == -1) {
>>> - return -socket_error();
>>> + ret = tcp_server_start(host_port,&s);
>>> + if (ret< 0) {
>>> + return ret;
>>> }
>>>
>>> - val = 1;
>>> - setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (const char *)&val,
>>> sizeof(val));
>>> -
>>> - if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
>>> - goto err;
>>> - }
>>> if (listen(s, 1) == -1) {
>>> goto err;
>>> }
>>> diff --git a/net.c b/net.c
>>> index c34474f..f63014c 100644
>>> --- a/net.c
>>> +++ b/net.c
>>> @@ -99,6 +99,114 @@ static int get_str_sep(char *buf, int buf_size, const
>>> char **pp, int sep)
>>> return 0;
>>> }
>>>
>>> +static int tcp_server_bind(int fd, struct addrinfo *rp)
>>> +{
>>> + int ret;
>>> + int val = 1;
>>> +
>>> + /* allow fast reuse */
>>> + setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (const char *)&val,
>>> sizeof(val));
>>> +
>>> + ret = bind(fd, rp->ai_addr, rp->ai_addrlen);
>>> +
>>> + if (ret == -1) {
>>> + ret = -socket_error();
>>> + }
>>> + return ret;
>>> +
>>> +}
>>> +
>>> +static int tcp_client_connect(int fd, struct addrinfo *rp)
>>> +{
>>> + int ret;
>>> +
>>> + do {
>>> + ret = connect(fd, rp->ai_addr, rp->ai_addrlen);
>>> + if (ret == -1) {
>>> + ret = -socket_error();
>>> + }
>>> + } while (ret == -EINTR);
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +
>>> +static int tcp_start_common(const char *str, int *fd, bool server)
>>> +{
>>> + char hostname[512];
>>> + const char *service;
>>> + const char *name;
>>> + struct addrinfo hints;
>>> + struct addrinfo *result, *rp;
>>> + int s;
>>> + int sfd;
>>> + int ret = -EINVAL;
>>> +
>>> + *fd = -1;
>>> + service = str;
>>> + if (get_str_sep(hostname, sizeof(hostname),&service, ':')< 0) {
>>> + return -EINVAL;
>>> + }
>>
>> Separating host name and port at the first colon looks wrong for IPv6.
>
> I fixed this in [PATCH 3/4] net: split hostname and service by last colon
Noticed it later. That's why I suggested reordering the patches in my
reply to PATCH 0/4.
Kevin