Using libvirt to do live migration over RDMA via ip v6 address failed.
For example:
# virsh migrate --live --migrateuri rdma://[deba::2222]:49152 \
rhel73_host1_guest1 qemu+ssh://[deba::2222]/system --verbose
root@deba::2222's password:
error: internal error: unable to execute QEMU command 'migrate': RDMA ERROR:
could not rdma_getaddrinfo address deba
As we can see, the ip v6 address used by rdma_getaddrinfo() has only "deba"
part. It should be "deba::2222".
1) According to rfc 3986, a literal ip v6 address should be enclosed
in '[' and ']'.
When using virsh command to do live migration via ip v6 addresss, user
will input the ip v6 address with brackets (i.e. rdma://[deba::2222]:49152).
libvirt will parse command line option by calling virURIParse().
Inside it calls virStringStripIPv6Brackets() to strip off the brackets.
The uri passed in to virURIParse() is:
"uri = rdma://[deba::2222]:49152"
Inside virURIParse() routine, it will strip off the bracket '[' and ']' if
it's ip v6 address. Then save the ip v6 address in this format "deba::2222"
in the virURI->server field, and to be passed to qemu.
2) At the beginning of migration, in qemu's qemu_rdma_data_init(host_port)
routine, it calls inet_parse(host_port) routine to parse the ip v6 address and
port string obtained from libvirt.
The input string host_port passed to qemu_rdma_data_init() can be:
"hostname:port", or
"ipv4address:port", or
"[ipv6address]:port" (i.e "[deba::2222]:49152"), or
"ipv6address:port" (i.e "deba::2222:49152").
Existing qemu api inet_parse() can handle the above first 3 cases properly,
but didn't handle the last case ("ipv6address:port") correctly.
In this live migration over rdma via ip v6 address case, the server ip v6
address obtained from libvirt doesn't contain the brackets '[' and ']'
(i.e. "deba::2222:49152"). It caused inet_parse() to parse only "deba" part,
and stopped at the 1st colon ':'. As the result, the subsequent
rdma_getaddrinfo() with ip address "deba" will fail.
If we don't strip off brackets '[' and ']' for an ip v6 address in libvirt's
virURIParse(), it will cause libvirt ipv6 ssh authentication failure.
NOTE:
If using libvirt to do live migration over TCP via ip v6 address:
# virsh migrate --live --migrateuri tcp://[deba::2222]:49152 \
rhel73_host1_guest1 qemu+ssh://[deba::2222]/system --verbose
It works fine.
In migrateuri of tcp case, libvirt will call virNetSocketNewConnectTCP()
directly to connect to remote "deba::2222:49152" after it strips off
the bracket '[' and ']' for an ip v6 address.
On qemu side, fd_start_outgoing_migration() will be called to do migration.
It doesn't call inet_parse(). So we don't see issue in tcp case.
Solution:
I choose to fix the code in qemu's inet_parse() routine to parse the
ip v6 addresss w/o brackets properly (i.e. "deba::2222:49152" format).
Signed-off-by: David Dai <z...@linux.vnet.ibm.com>
---
util/qemu-sockets.c | 28 +++++++++++++++++++++++-----
1 files changed, 23 insertions(+), 5 deletions(-)
diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
index 7c120c4..e09191c 100644
--- a/util/qemu-sockets.c
+++ b/util/qemu-sockets.c
@@ -584,6 +584,8 @@ InetSocketAddress *inet_parse(const char *str, Error **errp)
char port[33];
int to;
int pos;
+ char *first_col_p = strchr(str, ':');
+ char *last_col_p = strrchr(str, ':');
addr = g_new0(InetSocketAddress, 1);
@@ -595,11 +597,27 @@ InetSocketAddress *inet_parse(const char *str, Error
**errp)
error_setg(errp, "error parsing port in address '%s'", str);
goto fail;
}
- } else if (str[0] == '[') {
- /* IPv6 addr */
- if (sscanf(str, "[%64[^]]]:%32[^,]%n", host, port, &pos) != 2) {
- error_setg(errp, "error parsing IPv6 address '%s'", str);
- goto fail;
+ } else if (first_col_p != last_col_p) {
+ if (str[0] != '[') {
+ /* IPv6 addr w/o brackets */
+ char *port_p;
+ char *comma_p;
+
+ pstrcpy(host, sizeof(host), str);
+ port_p = strrchr(host, ':');
+ *port_p++ = '\0';
+ pstrcpy(port, sizeof(port), port_p);
+ comma_p = strchr(port, ',');
+ if (comma_p != NULL) {
+ *comma_p = '\0';
+ }
+ pos = strlen(host) + strlen(port) + 1;
+ } else {
+ /* IPv6 addr with brackets */
+ if (2 != sscanf(str, "[%64[^]]]:%32[^,]%n", host, port, &pos)) {
+ error_setg(errp, "error parsing IPv6 address '%s'", str);
+ goto fail;
+ }
}
addr->ipv6 = addr->has_ipv6 = true;
} else {
--
1.7.1
