11:15 p.m.
This patch adds virNetlinkNewLink for simplifying virNetDevMacVLanCreate
and virNetDevBridgeCreate.
Signed-off-by: Shi Lei <shi_lei(a)massclouds.com>
---
src/libvirt_private.syms | 1 +
src/util/virnetdevbridge.c | 73 +++--------------------
src/util/virnetdevmacvlan.c | 137 ++++++++++++++------------------------------
src/util/virnetlink.c | 104 +++++++++++++++++++++++++++++++++
src/util/virnetlink.h | 8 +++
5 files changed, 164 insertions(+), 159 deletions(-)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 47ea35f..23931ba 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2439,6 +2439,7 @@ virNetlinkEventServiceStop;
virNetlinkEventServiceStopAll;
virNetlinkGetErrorCode;
virNetlinkGetNeighbor;
+virNetlinkNewLink;
virNetlinkShutdown;
virNetlinkStartup;
diff --git a/src/util/virnetdevbridge.c b/src/util/virnetdevbridge.c
index bc377b5..1f5b37e 100644
--- a/src/util/virnetdevbridge.c
+++ b/src/util/virnetdevbridge.c
@@ -417,77 +417,22 @@ virNetDevBridgeCreate(const char *brname)
{
/* use a netlink RTM_NEWLINK message to create the bridge */
const char *type = "bridge";
- struct nlmsgerr *err;
- struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
- unsigned int recvbuflen;
- struct nlattr *linkinfo;
- VIR_AUTOPTR(virNetlinkMsg) nl_msg = NULL;
- VIR_AUTOFREE(struct nlmsghdr *) resp = NULL;
+ int error = 0;
- nl_msg = nlmsg_alloc_simple(RTM_NEWLINK,
- NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL);
- if (!nl_msg) {
- virReportOOMError();
- return -1;
- }
-
- if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0)
- goto buffer_too_small;
- if (nla_put(nl_msg, IFLA_IFNAME, strlen(brname)+1, brname) < 0)
- goto buffer_too_small;
- if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO)))
- goto buffer_too_small;
- if (nla_put(nl_msg, IFLA_INFO_KIND, strlen(type), type) < 0)
- goto buffer_too_small;
- nla_nest_end(nl_msg, linkinfo);
-
- if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, 0, 0,
- NETLINK_ROUTE, 0) < 0) {
- return -1;
- }
-
- if (recvbuflen < NLMSG_LENGTH(0) || resp == NULL)
- goto malformed_resp;
-
- switch (resp->nlmsg_type) {
- case NLMSG_ERROR:
- err = (struct nlmsgerr *)NLMSG_DATA(resp);
- if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err)))
- goto malformed_resp;
-
- if (err->error < 0) {
+ if (virNetlinkNewLink(NULL, brname, NULL, type, NULL, NULL, &error) < 0) {
# if defined(HAVE_STRUCT_IFREQ) && defined(SIOCBRADDBR)
- if (err->error == -EOPNOTSUPP) {
- /* fallback to ioctl if netlink doesn't support creating
- * bridges
- */
- return virNetDevBridgeCreateWithIoctl(brname);
- }
-# endif
-
- virReportSystemError(-err->error,
- _("error creating bridge interface %s"),
- brname);
- return -1;
+ if (error == -EOPNOTSUPP) {
+ /* fallback to ioctl if netlink doesn't support creating bridges */
+ return virNetDevBridgeCreateWithIoctl(brname);
}
- break;
+# endif
+ virReportSystemError(-error, _("error creating bridge interface %s"),
+ brname);
- case NLMSG_DONE:
- break;
- default:
- goto malformed_resp;
+ return -1;
}
return 0;
-
- malformed_resp:
- virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
- _("malformed netlink response message"));
- return -1;
- buffer_too_small:
- virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
- _("allocated netlink buffer is too small"));
- return -1;
}
diff --git a/src/util/virnetdevmacvlan.c b/src/util/virnetdevmacvlan.c
index 2035b1f..1629add 100644
--- a/src/util/virnetdevmacvlan.c
+++ b/src/util/virnetdevmacvlan.c
@@ -283,6 +283,37 @@ virNetDevMacVLanReleaseName(const char *name)
}
+static int
+virNetDevMacVLanCreateCallback(struct nl_msg *nl_msg, const void *opaque)
+{
+ const uint32_t *mode = (const uint32_t *) opaque;
+ if (!nl_msg || !opaque) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("nl_msg %p or opaque %p is NULL"),
+ nl_msg, opaque);
+ return -1;
+ }
+
+ if (*mode > 0) {
+ struct nlattr *info_data;
+ if (!(info_data = nla_nest_start(nl_msg, IFLA_INFO_DATA)))
+ goto buffer_too_small;
+
+ if (nla_put(nl_msg, IFLA_MACVLAN_MODE, sizeof(*mode), mode) < 0)
+ goto buffer_too_small;
+
+ nla_nest_end(nl_msg, info_data);
+ }
+
+ return 0;
+
+ buffer_too_small:
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("allocated netlink buffer is too small"));
+ return -1;
+}
+
+
/**
* virNetDevMacVLanCreate:
*
@@ -307,113 +338,29 @@ virNetDevMacVLanCreate(const char *ifname,
uint32_t macvlan_mode,
int *retry)
{
- int rc = -1;
- struct nlmsgerr *err;
- struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
int ifindex;
- unsigned int recvbuflen;
- struct nl_msg *nl_msg;
- struct nlattr *linkinfo, *info_data;
- char macstr[VIR_MAC_STRING_BUFLEN];
- VIR_AUTOFREE(struct nlmsghdr *) resp = NULL;
-
- if (virNetDevGetIndex(srcdev, &ifindex) < 0)
- return -1;
-
+ int error = 0;
*retry = 0;
- nl_msg = nlmsg_alloc_simple(RTM_NEWLINK,
- NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL);
- if (!nl_msg) {
- virReportOOMError();
+ if (virNetDevGetIndex(srcdev, &ifindex) < 0)
return -1;
- }
-
- if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0)
- goto buffer_too_small;
-
- if (nla_put_u32(nl_msg, IFLA_LINK, ifindex) < 0)
- goto buffer_too_small;
-
- if (nla_put(nl_msg, IFLA_ADDRESS, VIR_MAC_BUFLEN, macaddress) < 0)
- goto buffer_too_small;
-
- if (ifname &&
- nla_put(nl_msg, IFLA_IFNAME, strlen(ifname)+1, ifname) < 0)
- goto buffer_too_small;
- if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO)))
- goto buffer_too_small;
-
- if (nla_put(nl_msg, IFLA_INFO_KIND, strlen(type), type) < 0)
- goto buffer_too_small;
-
- if (macvlan_mode > 0) {
- if (!(info_data = nla_nest_start(nl_msg, IFLA_INFO_DATA)))
- goto buffer_too_small;
-
- if (nla_put(nl_msg, IFLA_MACVLAN_MODE, sizeof(macvlan_mode),
- &macvlan_mode) < 0)
- goto buffer_too_small;
-
- nla_nest_end(nl_msg, info_data);
- }
-
- nla_nest_end(nl_msg, linkinfo);
-
- if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, 0, 0,
- NETLINK_ROUTE, 0) < 0) {
- goto cleanup;
- }
-
- if (recvbuflen < NLMSG_LENGTH(0) || resp == NULL)
- goto malformed_resp;
-
- switch (resp->nlmsg_type) {
- case NLMSG_ERROR:
- err = (struct nlmsgerr *)NLMSG_DATA(resp);
- if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err)))
- goto malformed_resp;
-
- switch (err->error) {
-
- case 0:
- break;
-
- case -EEXIST:
+ if (virNetlinkNewLink(&ifindex, ifname, macaddress, type,
+ virNetDevMacVLanCreateCallback, &macvlan_mode,
+ &error) < 0) {
+ char macstr[VIR_MAC_STRING_BUFLEN];
+ if (error == -EEXIST)
*retry = 1;
- goto cleanup;
-
- default:
- virReportSystemError(-err->error,
+ else
+ virReportSystemError(-error,
_("error creating %s interface %s@%s (%s)"),
type, ifname, srcdev,
virMacAddrFormat(macaddress, macstr));
- goto cleanup;
- }
- break;
-
- case NLMSG_DONE:
- break;
- default:
- goto malformed_resp;
+ return -1;
}
- rc = 0;
- cleanup:
- nlmsg_free(nl_msg);
- return rc;
-
- malformed_resp:
- virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
- _("malformed netlink response message"));
- goto cleanup;
-
- buffer_too_small:
- virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
- _("allocated netlink buffer is too small"));
- goto cleanup;
+ return 0;
}
/**
diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c
index 8f06446..817e347 100644
--- a/src/util/virnetlink.c
+++ b/src/util/virnetlink.c
@@ -489,6 +489,110 @@ virNetlinkDumpLink(const char *ifname, int ifindex,
/**
+ * virNetlinkNewLink:
+ *
+ * @ifindex: The index for the 'link' device
+ * @ifname: The name of the link
+ * @mac: The MAC address of the device
+ * @type: The type of device, i.e., "bridge", "macvtap",
"macvlan"
+ * @cb: The callback for filling in IFLA_INFO_DATA for this type
+ * @opaque: opaque for the callback
+ * @error: for retrieving error code
+ *
+ * Create a network "link" (aka interface aka device) with the given
+ * args. This works for many different types of network devices,
+ * including macvtap and bridges.
+ *
+ * Returns 0 on success, -1 on fatal error.
+ */
+int
+virNetlinkNewLink(const int *ifindex,
+ const char *ifname,
+ const virMacAddr *mac,
+ const char *type,
+ virNetlinkNewLinkCallback cb,
+ const void *opaque,
+ int *error)
+{
+ struct nlmsgerr *err;
+ struct nlattr *linkinfo;
+ unsigned int buflen;
+ struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
+ VIR_AUTOPTR(virNetlinkMsg) nl_msg = NULL;
+ VIR_AUTOFREE(struct nlmsghdr *) resp = NULL;
+
+ *error = 0;
+
+ nl_msg = nlmsg_alloc_simple(RTM_NEWLINK,
+ NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL);
+ if (!nl_msg) {
+ virReportOOMError();
+ return -1;
+ }
+
+ if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0)
+ goto buffer_too_small;
+
+ if (ifindex && nla_put_u32(nl_msg, IFLA_LINK, *ifindex) < 0)
+ goto buffer_too_small;
+
+ if (mac && nla_put(nl_msg, IFLA_ADDRESS, VIR_MAC_BUFLEN, mac) < 0)
+ goto buffer_too_small;
+
+ if (ifname && nla_put(nl_msg, IFLA_IFNAME, strlen(ifname)+1, ifname) < 0)
+ goto buffer_too_small;
+
+ if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO)))
+ goto buffer_too_small;
+
+ if (nla_put(nl_msg, IFLA_INFO_KIND, strlen(type), type) < 0)
+ goto buffer_too_small;
+
+ if (cb && cb(nl_msg, opaque) < 0)
+ return -1;
+
+ nla_nest_end(nl_msg, linkinfo);
+
+ if (virNetlinkCommand(nl_msg, &resp, &buflen, 0, 0, NETLINK_ROUTE, 0) <
0)
+ return -1;
+
+ if (buflen < NLMSG_LENGTH(0) || resp == NULL)
+ goto malformed_resp;
+
+ switch (resp->nlmsg_type) {
+ case NLMSG_ERROR:
+ err = (struct nlmsgerr *)NLMSG_DATA(resp);
+ if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err)))
+ goto malformed_resp;
+
+ if (err->error < 0) {
+ *error = err->error;
+ return -1;
+ }
+ break;
+
+ case NLMSG_DONE:
+ break;
+
+ default:
+ goto malformed_resp;
+ }
+
+ return 0;
+
+ malformed_resp:
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("malformed netlink response message"));
+ return -1;
+
+ buffer_too_small:
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("allocated netlink buffer is too small"));
+ return -1;
+}
+
+
+/**
* virNetlinkDelLink:
*
* @ifname: Name of the link
diff --git a/src/util/virnetlink.h b/src/util/virnetlink.h
index 1e1e616..195c7bb 100644
--- a/src/util/virnetlink.h
+++ b/src/util/virnetlink.h
@@ -65,6 +65,14 @@ int virNetlinkDumpCommand(struct nl_msg *nl_msg,
unsigned int protocol, unsigned int groups,
void *opaque);
+typedef int (*virNetlinkNewLinkCallback)(struct nl_msg *nl_msg,
+ const void *opaque);
+
+int virNetlinkNewLink(const int *ifindex, const char *ifname,
+ const virMacAddr *macaddress, const char *type,
+ virNetlinkNewLinkCallback cb, const void *opaque,
+ int *error);
+
typedef int (*virNetlinkDelLinkFallback)(const char *ifname);
int virNetlinkDelLink(const char *ifname, virNetlinkDelLinkFallback fallback);
--
2.7.4
6:43 a.m.
On Thu, Aug 23, 2018 at 12:15:08PM +0800, Shi Lei wrote:
This patch adds virNetlinkNewLink for simplifying
virNetDevMacVLanCreate
and virNetDevBridgeCreate.
Signed-off-by: Shi Lei <shi_lei(a)massclouds.com>
---
There are multiple changes happening in this patch so it will need to be split
into several patches, see below...
src/libvirt_private.syms | 1 +
src/util/virnetdevbridge.c | 73 +++--------------------
src/util/virnetdevmacvlan.c | 137 ++++++++++++++------------------------------
src/util/virnetlink.c | 104 +++++++++++++++++++++++++++++++++
src/util/virnetlink.h | 8 +++
5 files changed, 164 insertions(+), 159 deletions(-)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 47ea35f..23931ba 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2439,6 +2439,7 @@ virNetlinkEventServiceStop;
virNetlinkEventServiceStopAll;
virNetlinkGetErrorCode;
virNetlinkGetNeighbor;
+virNetlinkNewLink;
virNetlinkShutdown;
virNetlinkStartup;
diff --git a/src/util/virnetdevbridge.c b/src/util/virnetdevbridge.c
index bc377b5..1f5b37e 100644
--- a/src/util/virnetdevbridge.c
+++ b/src/util/virnetdevbridge.c
@@ -417,77 +417,22 @@ virNetDevBridgeCreate(const char *brname)
{
/* use a netlink RTM_NEWLINK message to create the bridge */
const char *type = "bridge";
- struct nlmsgerr *err;
- struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
- unsigned int recvbuflen;
- struct nlattr *linkinfo;
- VIR_AUTOPTR(virNetlinkMsg) nl_msg = NULL;
- VIR_AUTOFREE(struct nlmsghdr *) resp = NULL;
+ int error = 0;
- nl_msg = nlmsg_alloc_simple(RTM_NEWLINK,
- NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL);
- if (!nl_msg) {
- virReportOOMError();
- return -1;
- }
-
- if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0)
- goto buffer_too_small;
- if (nla_put(nl_msg, IFLA_IFNAME, strlen(brname)+1, brname) < 0)
- goto buffer_too_small;
- if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO)))
- goto buffer_too_small;
- if (nla_put(nl_msg, IFLA_INFO_KIND, strlen(type), type) < 0)
- goto buffer_too_small;
- nla_nest_end(nl_msg, linkinfo);
-
- if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, 0, 0,
- NETLINK_ROUTE, 0) < 0) {
- return -1;
- }
-
- if (recvbuflen < NLMSG_LENGTH(0) || resp == NULL)
- goto malformed_resp;
-
- switch (resp->nlmsg_type) {
- case NLMSG_ERROR:
- err = (struct nlmsgerr *)NLMSG_DATA(resp);
- if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err)))
- goto malformed_resp;
-
- if (err->error < 0) {
+ if (virNetlinkNewLink(NULL, brname, NULL, type, NULL, NULL, &error) < 0) {
# if defined(HAVE_STRUCT_IFREQ) && defined(SIOCBRADDBR)
- if (err->error == -EOPNOTSUPP) {
- /* fallback to ioctl if netlink doesn't support creating
- * bridges
- */
- return virNetDevBridgeCreateWithIoctl(brname);
- }
-# endif
-
- virReportSystemError(-err->error,
- _("error creating bridge interface %s"),
- brname);
- return -1;
+ if (error == -EOPNOTSUPP) {
+ /* fallback to ioctl if netlink doesn't support creating bridges */
+ return virNetDevBridgeCreateWithIoctl(brname);
}
- break;
+# endif
+ virReportSystemError(-error, _("error creating bridge interface %s"),
+ brname);
- case NLMSG_DONE:
- break;
- default:
- goto malformed_resp;
+ return -1;
}
return 0;
-
- malformed_resp:
- virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
- _("malformed netlink response message"));
- return -1;
- buffer_too_small:
- virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
- _("allocated netlink buffer is too small"));
- return -1;
}
diff --git a/src/util/virnetdevmacvlan.c b/src/util/virnetdevmacvlan.c
index 2035b1f..1629add 100644
--- a/src/util/virnetdevmacvlan.c
+++ b/src/util/virnetdevmacvlan.c
@@ -283,6 +283,37 @@ virNetDevMacVLanReleaseName(const char *name)
}
+static int
+virNetDevMacVLanCreateCallback(struct nl_msg *nl_msg, const void *opaque)
+{
+ const uint32_t *mode = (const uint32_t *) opaque;
+ if (!nl_msg || !opaque) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("nl_msg %p or opaque %p is NULL"),
+ nl_msg, opaque);
+ return -1;
+ }
+
+ if (*mode > 0) {
+ struct nlattr *info_data;
+ if (!(info_data = nla_nest_start(nl_msg, IFLA_INFO_DATA)))
+ goto buffer_too_small;
+
+ if (nla_put(nl_msg, IFLA_MACVLAN_MODE, sizeof(*mode), mode) < 0)
+ goto buffer_too_small;
+
+ nla_nest_end(nl_msg, info_data);
+ }
+
+ return 0;
+
+ buffer_too_small:
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("allocated netlink buffer is too small"));
+ return -1;
+}
Having a callback just to add a nested data into nl_msg doesn't feel like the
right approach, I'd expect a callback to do more specific stuff, this should be
special-cased in virNetlinkNewLink.
+
+
/**
* virNetDevMacVLanCreate:
*
@@ -307,113 +338,29 @@ virNetDevMacVLanCreate(const char *ifname,
uint32_t macvlan_mode,
int *retry)
{
^This replacement would be the last patch in the series.
- int rc = -1;
- struct nlmsgerr *err;
- struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
int ifindex;
- unsigned int recvbuflen;
- struct nl_msg *nl_msg;
- struct nlattr *linkinfo, *info_data;
- char macstr[VIR_MAC_STRING_BUFLEN];
- VIR_AUTOFREE(struct nlmsghdr *) resp = NULL;
-
- if (virNetDevGetIndex(srcdev, &ifindex) < 0)
- return -1;
-
+ int error = 0;
*retry = 0;
- nl_msg = nlmsg_alloc_simple(RTM_NEWLINK,
- NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL);
- if (!nl_msg) {
- virReportOOMError();
+ if (virNetDevGetIndex(srcdev, &ifindex) < 0)
return -1;
- }
-
- if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0)
- goto buffer_too_small;
-
- if (nla_put_u32(nl_msg, IFLA_LINK, ifindex) < 0)
- goto buffer_too_small;
-
- if (nla_put(nl_msg, IFLA_ADDRESS, VIR_MAC_BUFLEN, macaddress) < 0)
- goto buffer_too_small;
-
- if (ifname &&
- nla_put(nl_msg, IFLA_IFNAME, strlen(ifname)+1, ifname) < 0)
- goto buffer_too_small;
- if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO)))
- goto buffer_too_small;
-
- if (nla_put(nl_msg, IFLA_INFO_KIND, strlen(type), type) < 0)
- goto buffer_too_small;
-
- if (macvlan_mode > 0) {
- if (!(info_data = nla_nest_start(nl_msg, IFLA_INFO_DATA)))
- goto buffer_too_small;
-
- if (nla_put(nl_msg, IFLA_MACVLAN_MODE, sizeof(macvlan_mode),
- &macvlan_mode) < 0)
- goto buffer_too_small;
-
- nla_nest_end(nl_msg, info_data);
- }
-
- nla_nest_end(nl_msg, linkinfo);
-
- if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, 0, 0,
- NETLINK_ROUTE, 0) < 0) {
- goto cleanup;
- }
-
- if (recvbuflen < NLMSG_LENGTH(0) || resp == NULL)
- goto malformed_resp;
-
- switch (resp->nlmsg_type) {
- case NLMSG_ERROR:
- err = (struct nlmsgerr *)NLMSG_DATA(resp);
- if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err)))
- goto malformed_resp;
-
- switch (err->error) {
-
- case 0:
- break;
-
- case -EEXIST:
+ if (virNetlinkNewLink(&ifindex, ifname, macaddress, type,
+ virNetDevMacVLanCreateCallback, &macvlan_mode,
+ &error) < 0) {
+ char macstr[VIR_MAC_STRING_BUFLEN];
+ if (error == -EEXIST)
*retry = 1;
- goto cleanup;
-
- default:
- virReportSystemError(-err->error,
+ else
+ virReportSystemError(-error,
_("error creating %s interface %s@%s (%s)"),
type, ifname, srcdev,
virMacAddrFormat(macaddress, macstr));
- goto cleanup;
- }
- break;
-
- case NLMSG_DONE:
- break;
- default:
- goto malformed_resp;
+ return -1;
}
- rc = 0;
- cleanup:
- nlmsg_free(nl_msg);
- return rc;
-
- malformed_resp:
- virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
- _("malformed netlink response message"));
- goto cleanup;
-
- buffer_too_small:
- virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
- _("allocated netlink buffer is too small"));
- goto cleanup;
+ return 0;
}
/**
diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c
index 8f06446..817e347 100644
--- a/src/util/virnetlink.c
+++ b/src/util/virnetlink.c
@@ -489,6 +489,110 @@ virNetlinkDumpLink(const char *ifname, int ifindex,
/**
+ * virNetlinkNewLink:
Introduction of this function should come in a separate patch before you start
replacing the existing ones.
+ *
+ * @ifindex: The index for the 'link' device
+ * @ifname: The name of the link
+ * @mac: The MAC address of the device
Most of ^these attributes could be packed into a virNetlinkNewLinkData
structure (or something similarly named). You'll have to test check for
VIR_DOMAIN_NET_TYPE_DIRECT and VIR_NETDEV_MACVLAN_MODE_VEPA according to my
comments below inside <comment_block>...
+ * @type: The type of device, i.e., "bridge",
"macvtap", "macvlan"
+ * @cb: The callback for filling in IFLA_INFO_DATA for this type
I don't think callback will be necessary
+ * @opaque: opaque for the callback
+ * @error: for retrieving error code
^see below for my comment on return value...
+ *
+ * Create a network "link" (aka interface aka device) with the given
+ * args. This works for many different types of network devices,
+ * including macvtap and bridges.
+ *
+ * Returns 0 on success, -1 on fatal error.
Since this is a nice libvirt wrapper around the netlink communication
machinery, I think that returning -<netlink_error> in case of an error is
reasonable. Then, each of the callers of this API can handle the return values
as they please.
+ */
+int
+virNetlinkNewLink(const int *ifindex,
+ const char *ifname,
+ const virMacAddr *mac,
+ const char *type,
+ virNetlinkNewLinkCallback cb,
+ const void *opaque,
+ int *error)
+{
+ struct nlmsgerr *err;
+ struct nlattr *linkinfo;
+ unsigned int buflen;
+ struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
+ VIR_AUTOPTR(virNetlinkMsg) nl_msg = NULL;
+ VIR_AUTOFREE(struct nlmsghdr *) resp = NULL;
+
+ *error = 0;
+
+ nl_msg = nlmsg_alloc_simple(RTM_NEWLINK,
+ NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL);
+ if (!nl_msg) {
+ virReportOOMError();
+ return -1;
+ }
+
+ if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0)
+ goto buffer_too_small;
+
<comment_block>
+ if (ifindex && nla_put_u32(nl_msg, IFLA_LINK, *ifindex)
< 0)
pre-existing, but is there a particular reason why ^this has to be u32??
+ goto buffer_too_small;
+
+ if (mac && nla_put(nl_msg, IFLA_ADDRESS, VIR_MAC_BUFLEN, mac) < 0)
+ goto buffer_too_small;
Similarly, is there a reason why ^this is not necessary to be u32?
+
+ if (ifname && nla_put(nl_msg, IFLA_IFNAME, strlen(ifname)+1, ifname) <
0)
+ goto buffer_too_small;
+
+ if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO)))
Since we're already touching the code, I would find it more readable if ^this
was written as linkinfo = nla_nest_start. The reason for that is that it's not
immediately visible where the matching counterpart to "nla_nest_end" is.
+ goto buffer_too_small;
+
+ if (nla_put(nl_msg, IFLA_INFO_KIND, strlen(type), type) < 0)
I'm puzzled why ^this doesn't need strlen(foo)+1 instead of plain strlen(foo)
+ goto buffer_too_small;
</comment_block>
We could actually create a wrapper macro around nla_put which would make the
block (begin-end) tiny more readable. See my notes above, as I have further
questions...Now, the macros would again be a separate patch to make the change
more gradual. Depending on the comments to my questions above, the macro would
either take the size of the type and always call nla_put or a specialized
nla_put_<string|u32|whatever> function. I'm CC'ing Laine to help answering
my
questions inside <comment_block>.
Erik
+
+ if (cb && cb(nl_msg, opaque) < 0)
+ return -1;
+
+ nla_nest_end(nl_msg, linkinfo);
+
+ if (virNetlinkCommand(nl_msg, &resp, &buflen, 0, 0, NETLINK_ROUTE, 0) <
0)
+ return -1;
+
+ if (buflen < NLMSG_LENGTH(0) || resp == NULL)
+ goto malformed_resp;
+
+ switch (resp->nlmsg_type) {
+ case NLMSG_ERROR:
+ err = (struct nlmsgerr *)NLMSG_DATA(resp);
+ if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err)))
+ goto malformed_resp;
+
+ if (err->error < 0) {
+ *error = err->error;
+ return -1;
+ }
+ break;
+
+ case NLMSG_DONE:
+ break;
+
+ default:
+ goto malformed_resp;
+ }
+
+ return 0;
+
+ malformed_resp:
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("malformed netlink response message"));
+ return -1;
+
+ buffer_too_small:
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("allocated netlink buffer is too small"));
+ return -1;
+}
+
+
+/**
* virNetlinkDelLink:
*
* @ifname: Name of the link
diff --git a/src/util/virnetlink.h b/src/util/virnetlink.h
index 1e1e616..195c7bb 100644
--- a/src/util/virnetlink.h
+++ b/src/util/virnetlink.h
@@ -65,6 +65,14 @@ int virNetlinkDumpCommand(struct nl_msg *nl_msg,
unsigned int protocol, unsigned int groups,
void *opaque);
+typedef int (*virNetlinkNewLinkCallback)(struct nl_msg *nl_msg,
+ const void *opaque);
+
+int virNetlinkNewLink(const int *ifindex, const char *ifname,
+ const virMacAddr *macaddress, const char *type,
+ virNetlinkNewLinkCallback cb, const void *opaque,
+ int *error);
+
typedef int (*virNetlinkDelLinkFallback)(const char *ifname);
int virNetlinkDelLink(const char *ifname, virNetlinkDelLinkFallback fallback);
--
2.7.4
--
libvir-list mailing list
libvir-list(a)redhat.com
https://www.redhat.com/mailman/listinfo/libvir-list
1:27 a.m.
Thanks for your comments.
But I have several questions, please see below...
On 2018-08-29 at 19:43, Erik Skultety wrote:
On Thu, Aug 23, 2018 at 12:15:08PM +0800, Shi Lei wrote:
> This patch adds virNetlinkNewLink for simplifying virNetDevMacVLanCreate
> and virNetDevBridgeCreate.
>
> Signed-off-by: Shi Lei <shi_lei(a)massclouds.com>
> ---
There are multiple changes happening in this patch so it will need to be split
into several patches, see below...
Okay. Then the v2 series should be like:
[patch v2 0/4]: ... cover ...
[patch v2 1/4]: Add wrapper macros to make code more readable
[patch v2 2/4]: Introduce virNetlinkNewLink
[patch v2 3/4]: Replace the implementation of virNetDevBridgeCreate
[patch v2 4/4]: Replace the implementation of virNetDevMacVLanCreate
> src/libvirt_private.syms | 1 +
> src/util/virnetdevbridge.c | 73 +++--------------------
> src/util/virnetdevmacvlan.c | 137 ++++++++++++++------------------------------
> src/util/virnetlink.c | 104 +++++++++++++++++++++++++++++++++
> src/util/virnetlink.h | 8 +++
> 5 files changed, 164 insertions(+), 159 deletions(-)
>
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 47ea35f..23931ba 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -2439,6 +2439,7 @@ virNetlinkEventServiceStop;
> virNetlinkEventServiceStopAll;
> virNetlinkGetErrorCode;
> virNetlinkGetNeighbor;
> +virNetlinkNewLink;
> virNetlinkShutdown;
> virNetlinkStartup;
>
> diff --git a/src/util/virnetdevbridge.c b/src/util/virnetdevbridge.c
> index bc377b5..1f5b37e 100644
> --- a/src/util/virnetdevbridge.c
> +++ b/src/util/virnetdevbridge.c
> @@ -417,77 +417,22 @@ virNetDevBridgeCreate(const char *brname)
> {
> /* use a netlink RTM_NEWLINK message to create the bridge */
> const char *type = "bridge";
> - struct nlmsgerr *err;
> - struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
> - unsigned int recvbuflen;
> - struct nlattr *linkinfo;
> - VIR_AUTOPTR(virNetlinkMsg) nl_msg = NULL;
> - VIR_AUTOFREE(struct nlmsghdr *) resp = NULL;
> + int error = 0;
>
> - nl_msg = nlmsg_alloc_simple(RTM_NEWLINK,
> - NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL);
> - if (!nl_msg) {
> - virReportOOMError();
> - return -1;
> - }
> -
> - if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0)
> - goto buffer_too_small;
> - if (nla_put(nl_msg, IFLA_IFNAME, strlen(brname)+1, brname) < 0)
> - goto buffer_too_small;
> - if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO)))
> - goto buffer_too_small;
> - if (nla_put(nl_msg, IFLA_INFO_KIND, strlen(type), type) < 0)
> - goto buffer_too_small;
> - nla_nest_end(nl_msg, linkinfo);
> -
> - if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, 0, 0,
> - NETLINK_ROUTE, 0) < 0) {
> - return -1;
> - }
> -
> - if (recvbuflen < NLMSG_LENGTH(0) || resp == NULL)
> - goto malformed_resp;
> -
> - switch (resp->nlmsg_type) {
> - case NLMSG_ERROR:
> - err = (struct nlmsgerr *)NLMSG_DATA(resp);
> - if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err)))
> - goto malformed_resp;
> -
> - if (err->error < 0) {
> + if (virNetlinkNewLink(NULL, brname, NULL, type, NULL, NULL, &error) < 0)
{
> # if defined(HAVE_STRUCT_IFREQ) && defined(SIOCBRADDBR)
> - if (err->error == -EOPNOTSUPP) {
> - /* fallback to ioctl if netlink doesn't support creating
> - * bridges
> - */
> - return virNetDevBridgeCreateWithIoctl(brname);
> - }
> -# endif
> -
> - virReportSystemError(-err->error,
> - _("error creating bridge interface %s"),
> - brname);
> - return -1;
> + if (error == -EOPNOTSUPP) {
> + /* fallback to ioctl if netlink doesn't support creating bridges */
> + return virNetDevBridgeCreateWithIoctl(brname);
> }
> - break;
> +# endif
> + virReportSystemError(-error, _("error creating bridge interface
%s"),
> + brname);
>
> - case NLMSG_DONE:
> - break;
> - default:
> - goto malformed_resp;
> + return -1;
> }
>
> return 0;
> -
> - malformed_resp:
> - virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> - _("malformed netlink response message"));
> - return -1;
> - buffer_too_small:
> - virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> - _("allocated netlink buffer is too small"));
> - return -1;
> }
>
>
> diff --git a/src/util/virnetdevmacvlan.c b/src/util/virnetdevmacvlan.c
> index 2035b1f..1629add 100644
> --- a/src/util/virnetdevmacvlan.c
> +++ b/src/util/virnetdevmacvlan.c
> @@ -283,6 +283,37 @@ virNetDevMacVLanReleaseName(const char *name)
> }
>
>
> +static int
> +virNetDevMacVLanCreateCallback(struct nl_msg *nl_msg, const void *opaque)
> +{
> + const uint32_t *mode = (const uint32_t *) opaque;
> + if (!nl_msg || !opaque) {
> + virReportError(VIR_ERR_INTERNAL_ERROR,
> + _("nl_msg %p or opaque %p is NULL"),
> + nl_msg, opaque);
> + return -1;
> + }
> +
> + if (*mode > 0) {
> + struct nlattr *info_data;
> + if (!(info_data = nla_nest_start(nl_msg, IFLA_INFO_DATA)))
> + goto buffer_too_small;
> +
> + if (nla_put(nl_msg, IFLA_MACVLAN_MODE, sizeof(*mode), mode) < 0)
> + goto buffer_too_small;
> +
> + nla_nest_end(nl_msg, info_data);
> + }
> +
> + return 0;
> +
> + buffer_too_small:
> + virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> + _("allocated netlink buffer is too small"));
> + return -1;
> +}
Having a callback just to add a nested data into nl_msg doesn't feel like the
right approach, I'd expect a callback to do more specific stuff, this should be
special-cased in virNetlinkNewLink.
I looked through the code for ip-link in iproute2 which could be a good example
for netlink. And I found that the differences of attributes of various net-devices are
confined to IFLA_INFO_DATA or IFLA_INFO_SLAVE_DATA(this is not used in libvirt).
The code fragment in iplink.c:
if (ulinep && !strcmp(ulinep, "_slave")) {
... ...
lu = get_link_slave_kind(slavebuf);
iflatype = IFLA_INFO_SLAVE_DATA;
} else {
=> lu = get_link_kind(type); /* Get pointer to the driver for this
type */
=> iflatype = IFLA_INFO_DATA; /* NEST will be for IFLA_INFO_DATA */
}
if (lu && argc) {
=> struct rtattr *data = addattr_nest(&req.n, sizeof(req), iflatype); /*
NEST BEGIN */
****************************
if (lu->parse_opt &&
lu->parse_opt(lu, argc, argv, &req.n))
return -1;
****************************
^The lu points to various types of net-drivers(e.g. macvlan/bridge/vxlan/vlan
...)
which pack all special self-attributes in their parse_opt callback
=> addattr_nest_end(&req.n, data); /* NEST END */
So I think that it's reasonable for us to have a callback to handle it just as
iproute2
since iproute2 could almost create all the types of net-devices.
> +
> +
> /**
> * virNetDevMacVLanCreate:
> *
> @@ -307,113 +338,29 @@ virNetDevMacVLanCreate(const char *ifname,
> uint32_t macvlan_mode,
> int *retry)
> {
^This replacement would be the last patch in the series.
Okay.
> - int rc = -1;
> - struct nlmsgerr *err;
> - struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
> int ifindex;
> - unsigned int recvbuflen;
> - struct nl_msg *nl_msg;
> - struct nlattr *linkinfo, *info_data;
> - char macstr[VIR_MAC_STRING_BUFLEN];
> - VIR_AUTOFREE(struct nlmsghdr *) resp = NULL;
> -
> - if (virNetDevGetIndex(srcdev, &ifindex) < 0)
> - return -1;
> -
> + int error = 0;
> *retry = 0;
>
> - nl_msg = nlmsg_alloc_simple(RTM_NEWLINK,
> - NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL);
> - if (!nl_msg) {
> - virReportOOMError();
> + if (virNetDevGetIndex(srcdev, &ifindex) < 0)
> return -1;
> - }
> -
> - if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0)
> - goto buffer_too_small;
> -
> - if (nla_put_u32(nl_msg, IFLA_LINK, ifindex) < 0)
> - goto buffer_too_small;
> -
> - if (nla_put(nl_msg, IFLA_ADDRESS, VIR_MAC_BUFLEN, macaddress) < 0)
> - goto buffer_too_small;
> -
> - if (ifname &&
> - nla_put(nl_msg, IFLA_IFNAME, strlen(ifname)+1, ifname) < 0)
> - goto buffer_too_small;
>
> - if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO)))
> - goto buffer_too_small;
> -
> - if (nla_put(nl_msg, IFLA_INFO_KIND, strlen(type), type) < 0)
> - goto buffer_too_small;
> -
> - if (macvlan_mode > 0) {
> - if (!(info_data = nla_nest_start(nl_msg, IFLA_INFO_DATA)))
> - goto buffer_too_small;
> -
> - if (nla_put(nl_msg, IFLA_MACVLAN_MODE, sizeof(macvlan_mode),
> - &macvlan_mode) < 0)
> - goto buffer_too_small;
> -
> - nla_nest_end(nl_msg, info_data);
> - }
> -
> - nla_nest_end(nl_msg, linkinfo);
> -
> - if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, 0, 0,
> - NETLINK_ROUTE, 0) < 0) {
> - goto cleanup;
> - }
> -
> - if (recvbuflen < NLMSG_LENGTH(0) || resp == NULL)
> - goto malformed_resp;
> -
> - switch (resp->nlmsg_type) {
> - case NLMSG_ERROR:
> - err = (struct nlmsgerr *)NLMSG_DATA(resp);
> - if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err)))
> - goto malformed_resp;
> -
> - switch (err->error) {
> -
> - case 0:
> - break;
> -
> - case -EEXIST:
> + if (virNetlinkNewLink(&ifindex, ifname, macaddress, type,
> + virNetDevMacVLanCreateCallback, &macvlan_mode,
> + &error) < 0) {
> + char macstr[VIR_MAC_STRING_BUFLEN];
> + if (error == -EEXIST)
> *retry = 1;
> - goto cleanup;
> -
> - default:
> - virReportSystemError(-err->error,
> + else
> + virReportSystemError(-error,
> _("error creating %s interface %s@%s
(%s)"),
> type, ifname, srcdev,
> virMacAddrFormat(macaddress, macstr));
> - goto cleanup;
> - }
> - break;
> -
> - case NLMSG_DONE:
> - break;
>
> - default:
> - goto malformed_resp;
> + return -1;
> }
>
> - rc = 0;
> - cleanup:
> - nlmsg_free(nl_msg);
> - return rc;
> -
> - malformed_resp:
> - virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> - _("malformed netlink response message"));
> - goto cleanup;
> -
> - buffer_too_small:
> - virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> - _("allocated netlink buffer is too small"));
> - goto cleanup;
> + return 0;
> }
>
> /**
> diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c
> index 8f06446..817e347 100644
> --- a/src/util/virnetlink.c
> +++ b/src/util/virnetlink.c
> @@ -489,6 +489,110 @@ virNetlinkDumpLink(const char *ifname, int ifindex,
>
>
> /**
> + * virNetlinkNewLink:
Introduction of this function should come in a separate patch before you start
replacing the existing ones.
Okay.
> + *
> + * @ifindex: The index for the 'link' device
> + * @ifname: The name of the link
> + * @mac: The MAC address of the device
Most of ^these attributes could be packed into a virNetlinkNewLinkData
structure (or something similarly named). You'll have to test check for
VIR_DOMAIN_NET_TYPE_DIRECT and VIR_NETDEV_MACVLAN_MODE_VEPA according to my
comments below inside <comment_block>...
I have studied your comments inside <comment_block>, but I still don't know how
to
test check for VIR_DOMAIN_NET_TYPE_DIRECT and VIR_NETDEV_MACVLAN_MODE_VEPA.
Could you explain it for me? :-)
> + * @type: The type of device, i.e., "bridge", "macvtap",
"macvlan"
> + * @cb: The callback for filling in IFLA_INFO_DATA for this type
I don't think callback will be necessary
I think that it's reasonable to use callback here.
Another mode might be:
1) pre-alloc buffer and fill in IFLA_INFO_DATA
2) pass the buffer pointer as a param into virNetlinkNewLink which will
embed it into nlmsg
3) free the buffer
I think that this mode might be a bit more complicated and it's hard to find good
references.
> + * @opaque: opaque for the callback
> + * @error: for retrieving error code
^see below for my comment on return value...
Okay.
> + *
> + * Create a network "link" (aka interface aka device) with the given
> + * args. This works for many different types of network devices,
> + * including macvtap and bridges.
> + *
> + * Returns 0 on success, -1 on fatal error.
Since this is a nice libvirt wrapper around the netlink communication
machinery, I think that returning -<netlink_error> in case of an error is
reasonable. Then, each of the callers of this API can handle the return values
as they please.
Okay. I will use netlink error as return-value.
But how to handle -1?
1) always return -1 for *other* failures
2) return -ENOMEM for OutofMemory; return -ENOBUFS for buffer_too_small; ...
I should take which one?
> + */
> +int
> +virNetlinkNewLink(const int *ifindex,
> + const char *ifname,
> + const virMacAddr *mac,
> + const char *type,
> + virNetlinkNewLinkCallback cb,
> + const void *opaque,
> + int *error)
> +{
> + struct nlmsgerr *err;
> + struct nlattr *linkinfo;
> + unsigned int buflen;
> + struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
> + VIR_AUTOPTR(virNetlinkMsg) nl_msg = NULL;
> + VIR_AUTOFREE(struct nlmsghdr *) resp = NULL;
> +
> + *error = 0;
> +
> + nl_msg = nlmsg_alloc_simple(RTM_NEWLINK,
> + NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL);
> + if (!nl_msg) {
> + virReportOOMError();
> + return -1;
> + }
> +
> + if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0)
> + goto buffer_too_small;
> +
No offence. Let me try talking about nla_put* in comment_block.
<comment_block>
> + if (ifindex && nla_put_u32(nl_msg, IFLA_LINK, *ifindex) < 0)
pre-existing, but is there a particular reason why ^this has to be u32??
prototype of nla_put_u32:
int nla_put_u32(struct nl_msg *msg, int attrtype, uint32_t value);
It is used for adding 32 bit integer into msg.
We got ifindex by calling ioctl with SIOCGIFINDEX and this ifindex >= 0.
So I think that it's right to use nla_put_u32.
> + goto buffer_too_small;
> +
> + if (mac && nla_put(nl_msg, IFLA_ADDRESS, VIR_MAC_BUFLEN, mac) < 0)
> + goto buffer_too_small;
Similarly, is there a reason why ^this is not necessary to be u32?
prototype of nla_put:
int nla_put(struct nl_msg *msg, int attrtype, int datalen, const void *data);
It means put a sequence of octets into msg. It could be used for string and
other packed struct.
The type of mac is struct virMacAddr which size is VIR_MAC_BUFLEN.
So I think it's right.
> +
> + if (ifname && nla_put(nl_msg, IFLA_IFNAME, strlen(ifname)+1, ifname)
< 0)
> + goto buffer_too_small;
> +
> + if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO)))
Since we're already touching the code, I would find it more readable if ^this
was written as linkinfo = nla_nest_start. The reason for that is that it's not
immediately visible where the matching counterpart to "nla_nest_end" is.
Okay.
> + goto buffer_too_small;
> +
> + if (nla_put(nl_msg, IFLA_INFO_KIND, strlen(type), type) < 0)
I'm puzzled why ^this doesn't need strlen(foo)+1 instead of plain strlen(foo)
This code is same as iproute2. There's no problem here.
In net/core/rtnetlink.c of kernel (source v4.4.0):
nla_strlcpy(kind, linkinfo[IFLA_INFO_KIND], sizeof(kind));
and the implementation of nla_strlcpy:
size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
{
size_t srclen = nla_len(nla); /* whatever it is strlen(foo)+1 or strlen(foo) */
char *src = nla_data(nla);
=> if (srclen > 0 && src[srclen - 1] == '\0')
=> srclen--;
But I think it should always be strlen(foo)+1 for consistency of code.
> + goto buffer_too_small;
</comment_block>
We could actually create a wrapper macro around nla_put which would make the
block (begin-end) tiny more readable. See my notes above, as I have further
questions...Now, the macros would again be a separate patch to make the change
more gradual. Depending on the comments to my questions above, the macro would
either take the size of the type and always call nla_put or a specialized
nla_put_<string|u32|whatever> function. I'm CC'ing Laine to help answering
my
questions inside <comment_block>.
Erik
I think that the usage of nla_put* is clear now.
So I don't know how to create wrapper macros.
Could you give me some instructions for it?
Regards,
Shi Lei
> +
> + if (cb && cb(nl_msg, opaque) < 0)
> + return -1;
> +
> + nla_nest_end(nl_msg, linkinfo);
> +
> + if (virNetlinkCommand(nl_msg, &resp, &buflen, 0, 0, NETLINK_ROUTE, 0)
< 0)
> + return -1;
> +
> + if (buflen < NLMSG_LENGTH(0) || resp == NULL)
> + goto malformed_resp;
> +
> + switch (resp->nlmsg_type) {
> + case NLMSG_ERROR:
> + err = (struct nlmsgerr *)NLMSG_DATA(resp);
> + if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err)))
> + goto malformed_resp;
> +
> + if (err->error < 0) {
> + *error = err->error;
> + return -1;
> + }
> + break;
> +
> + case NLMSG_DONE:
> + break;
> +
> + default:
> + goto malformed_resp;
> + }
> +
> + return 0;
> +
> + malformed_resp:
> + virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> + _("malformed netlink response message"));
> + return -1;
> +
> + buffer_too_small:
> + virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> + _("allocated netlink buffer is too small"));
> + return -1;
> +}
> +
> +
> +/**
> * virNetlinkDelLink:
> *
> * @ifname: Name of the link
> diff --git a/src/util/virnetlink.h b/src/util/virnetlink.h
> index 1e1e616..195c7bb 100644
> --- a/src/util/virnetlink.h
> +++ b/src/util/virnetlink.h
> @@ -65,6 +65,14 @@ int virNetlinkDumpCommand(struct nl_msg *nl_msg,
> unsigned int protocol, unsigned int groups,
> void *opaque);
>
> +typedef int (*virNetlinkNewLinkCallback)(struct nl_msg *nl_msg,
> + const void *opaque);
> +
> +int virNetlinkNewLink(const int *ifindex, const char *ifname,
> + const virMacAddr *macaddress, const char *type,
> + virNetlinkNewLinkCallback cb, const void *opaque,
> + int *error);
> +
> typedef int (*virNetlinkDelLinkFallback)(const char *ifname);
>
> int virNetlinkDelLink(const char *ifname, virNetlinkDelLinkFallback fallback);
> --
> 2.7.4
>
>
> --
> libvir-list mailing list
> libvir-list(a)redhat.com
> https://www.redhat.com/mailman/listinfo/libvir-list
7:02 a.m.
On Thu, Aug 30, 2018 at 02:27:05PM +0800, Shi Lei wrote:
Thanks for your comments.
But I have several questions, please see below...
On 2018-08-29 at 19:43, Erik Skultety wrote:
>On Thu, Aug 23, 2018 at 12:15:08PM +0800, Shi Lei wrote:
>> This patch adds virNetlinkNewLink for simplifying virNetDevMacVLanCreate
>> and virNetDevBridgeCreate.
>>
>> Signed-off-by: Shi Lei <shi_lei(a)massclouds.com>
>> ---
>
>There are multiple changes happening in this patch so it will need to be split
>into several patches, see below...
Okay. Then the v2 series should be like:
[patch v2 0/4]: ... cover ...
[patch v2 1/4]: Add wrapper macros to make code more readable
[patch v2 2/4]: Introduce virNetlinkNewLink
2/4 would come before 1/4
[patch v2 3/4]: Replace the implementation of virNetDevBridgeCreate
[patch v2 4/4]: Replace the implementation of virNetDevMacVLanCreate
3/4 + 4/4 would be a single patch
...
>> +static int
>> +virNetDevMacVLanCreateCallback(struct nl_msg *nl_msg, const void *opaque)
>> +{
>> + const uint32_t *mode = (const uint32_t *) opaque;
>> + if (!nl_msg || !opaque) {
>> + virReportError(VIR_ERR_INTERNAL_ERROR,
>> + _("nl_msg %p or opaque %p is NULL"),
>> + nl_msg, opaque);
>> + return -1;
>> + }
>> +
>> + if (*mode > 0) {
>> + struct nlattr *info_data;
>> + if (!(info_data = nla_nest_start(nl_msg, IFLA_INFO_DATA)))
>> + goto buffer_too_small;
>> +
>> + if (nla_put(nl_msg, IFLA_MACVLAN_MODE, sizeof(*mode), mode) < 0)
>> + goto buffer_too_small;
>> +
>> + nla_nest_end(nl_msg, info_data);
>> + }
>> +
>> + return 0;
>> +
>> + buffer_too_small:
>> + virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
>> + _("allocated netlink buffer is too small"));
>> + return -1;
>> +}
>
>Having a callback just to add a nested data into nl_msg doesn't feel like the
>right approach, I'd expect a callback to do more specific stuff, this should be
>special-cased in virNetlinkNewLink.
I looked through the code for ip-link in iproute2 which could be a good example
for netlink. And I found that the differences of attributes of various net-devices are
confined to IFLA_INFO_DATA or IFLA_INFO_SLAVE_DATA(this is not used in libvirt).
The code fragment in iplink.c:
if (ulinep && !strcmp(ulinep, "_slave")) {
... ...
lu = get_link_slave_kind(slavebuf);
iflatype = IFLA_INFO_SLAVE_DATA;
} else {
=> lu = get_link_kind(type); /* Get pointer to the driver for this
type */
=> iflatype = IFLA_INFO_DATA; /* NEST will be for IFLA_INFO_DATA */
}
if (lu && argc) {
=> struct rtattr *data = addattr_nest(&req.n, sizeof(req), iflatype); /*
NEST BEGIN */
****************************
if (lu->parse_opt &&
lu->parse_opt(lu, argc, argv, &req.n))
return -1;
****************************
^The lu points to various types of net-drivers(e.g. macvlan/bridge/vxlan/vlan
...)
which pack all special self-attributes in their parse_opt callback
=> addattr_nest_end(&req.n, data); /* NEST END */
So I think that it's reasonable for us to have a callback to handle it just as
iproute2
since iproute2 could almost create all the types of net-devices.
I went through the iproute2 code and it completely makes sense for them to
utilize callbacks here, given the amount of driver-specific options each of the
device type has. While I agree that we could make use of this in libvirt one
day, I don't feel like we need to do it now, since I don't think it brings
any noticeable benefit in its currently proposed form + as I already mentioned,
we can switch to this scheme once there are more than 1 netlink types which
could make use of it.
>
>> +
>> +
>> /**
>> * virNetDevMacVLanCreate:
>> *
>> @@ -307,113 +338,29 @@ virNetDevMacVLanCreate(const char *ifname,
>> uint32_t macvlan_mode,
>> int *retry)
>> {
>
>^This replacement would be the last patch in the series.
Okay.
>
>> - int rc = -1;
>> - struct nlmsgerr *err;
>> - struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
>> int ifindex;
>> - unsigned int recvbuflen;
>> - struct nl_msg *nl_msg;
>> - struct nlattr *linkinfo, *info_data;
>> - char macstr[VIR_MAC_STRING_BUFLEN];
>> - VIR_AUTOFREE(struct nlmsghdr *) resp = NULL;
>> -
>> - if (virNetDevGetIndex(srcdev, &ifindex) < 0)
>> - return -1;
>> -
>> + int error = 0;
>> *retry = 0;
>>
>> - nl_msg = nlmsg_alloc_simple(RTM_NEWLINK,
>> - NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL);
>> - if (!nl_msg) {
>> - virReportOOMError();
>> + if (virNetDevGetIndex(srcdev, &ifindex) < 0)
>> return -1;
>> - }
>> -
>> - if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) <
0)
>> - goto buffer_too_small;
>> -
>> - if (nla_put_u32(nl_msg, IFLA_LINK, ifindex) < 0)
>> - goto buffer_too_small;
>> -
>> - if (nla_put(nl_msg, IFLA_ADDRESS, VIR_MAC_BUFLEN, macaddress) < 0)
>> - goto buffer_too_small;
>> -
>> - if (ifname &&
>> - nla_put(nl_msg, IFLA_IFNAME, strlen(ifname)+1, ifname) < 0)
>> - goto buffer_too_small;
>>
>> - if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO)))
>> - goto buffer_too_small;
>> -
>> - if (nla_put(nl_msg, IFLA_INFO_KIND, strlen(type), type) < 0)
>> - goto buffer_too_small;
>> -
>> - if (macvlan_mode > 0) {
>> - if (!(info_data = nla_nest_start(nl_msg, IFLA_INFO_DATA)))
>> - goto buffer_too_small;
>> -
>> - if (nla_put(nl_msg, IFLA_MACVLAN_MODE, sizeof(macvlan_mode),
>> - &macvlan_mode) < 0)
>> - goto buffer_too_small;
>> -
>> - nla_nest_end(nl_msg, info_data);
>> - }
>> -
>> - nla_nest_end(nl_msg, linkinfo);
>> -
>> - if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, 0, 0,
>> - NETLINK_ROUTE, 0) < 0) {
>> - goto cleanup;
>> - }
>> -
>> - if (recvbuflen < NLMSG_LENGTH(0) || resp == NULL)
>> - goto malformed_resp;
>> -
>> - switch (resp->nlmsg_type) {
>> - case NLMSG_ERROR:
>> - err = (struct nlmsgerr *)NLMSG_DATA(resp);
>> - if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err)))
>> - goto malformed_resp;
>> -
>> - switch (err->error) {
>> -
>> - case 0:
>> - break;
>> -
>> - case -EEXIST:
>> + if (virNetlinkNewLink(&ifindex, ifname, macaddress, type,
>> + virNetDevMacVLanCreateCallback, &macvlan_mode,
>> + &error) < 0) {
>> + char macstr[VIR_MAC_STRING_BUFLEN];
>> + if (error == -EEXIST)
>> *retry = 1;
>> - goto cleanup;
>> -
>> - default:
>> - virReportSystemError(-err->error,
>> + else
>> + virReportSystemError(-error,
>> _("error creating %s interface %s@%s
(%s)"),
>> type, ifname, srcdev,
>> virMacAddrFormat(macaddress, macstr));
>> - goto cleanup;
>> - }
>> - break;
>> -
>> - case NLMSG_DONE:
>> - break;
>>
>> - default:
>> - goto malformed_resp;
>> + return -1;
>> }
>>
>> - rc = 0;
>> - cleanup:
>> - nlmsg_free(nl_msg);
>> - return rc;
>> -
>> - malformed_resp:
>> - virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
>> - _("malformed netlink response message"));
>> - goto cleanup;
>> -
>> - buffer_too_small:
>> - virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
>> - _("allocated netlink buffer is too small"));
>> - goto cleanup;
>> + return 0;
>> }
>>
>> /**
>> diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c
>> index 8f06446..817e347 100644
>> --- a/src/util/virnetlink.c
>> +++ b/src/util/virnetlink.c
>> @@ -489,6 +489,110 @@ virNetlinkDumpLink(const char *ifname, int ifindex,
>>
>>
>> /**
>> + * virNetlinkNewLink:
>
>Introduction of this function should come in a separate patch before you start
>replacing the existing ones.
Okay.
>
>> + *
>> + * @ifindex: The index for the 'link' device
>> + * @ifname: The name of the link
>> + * @mac: The MAC address of the device
>
>Most of ^these attributes could be packed into a virNetlinkNewLinkData
>structure (or something similarly named). You'll have to test check for
>VIR_DOMAIN_NET_TYPE_DIRECT and VIR_NETDEV_MACVLAN_MODE_VEPA according to my
>comments below inside <comment_block>...
I have studied your comments inside <comment_block>, but I still don't know
how to
test check for VIR_DOMAIN_NET_TYPE_DIRECT and VIR_NETDEV_MACVLAN_MODE_VEPA.
Could you explain it for me? :-)
Actually, I retract on checking the modes ^this way, I was hasty with my
response and then went through the code more thoroughly and realized that mode
corresponds to netlink modes rather than to libvirt MACVLAN_MODE_X and we have
a corresponding modemap for this. Not that it could not be achieved with our
enums, but it's just not worth passing it around, so we'll need to imo rely on
the @type string, which in this case would either be "macvtap" or
"macvlan".
>
>> + * @type: The type of device, i.e., "bridge", "macvtap",
"macvlan"
>> + * @cb: The callback for filling in IFLA_INFO_DATA for this type
>
>I don't think callback will be necessary
I think that it's reasonable to use callback here.
Another mode might be:
1) pre-alloc buffer and fill in IFLA_INFO_DATA
2) pass the buffer pointer as a param into virNetlinkNewLink which will
embed it into nlmsg
3) free the buffer
I think that this mode might be a bit more complicated and it's hard to find good
references.
>
>> + * @opaque: opaque for the callback
>> + * @error: for retrieving error code
>
>^see below for my comment on return value...
Okay.
>
>> + *
>> + * Create a network "link" (aka interface aka device) with the given
>> + * args. This works for many different types of network devices,
>> + * including macvtap and bridges.
>> + *
>> + * Returns 0 on success, -1 on fatal error.
>
<brain fart>
>Since this is a nice libvirt wrapper around the netlink
communication
>machinery, I think that returning -<netlink_error> in case of an error is
>reasonable. Then, each of the callers of this API can handle the return values
>as they please.
<brain fart/>
Okay. I will use netlink error as return-value.
But how to handle -1?
1) always return -1 for *other* failures
2) return -ENOMEM for OutofMemory; return -ENOBUFS for buffer_too_small; ...
Good point, we couldn't differentiate between -1 from libvirt and -ENOPERM or
-NLE_FAILURE (from libnl), so the @error variable should stay.
I should take which one?
>
>> + */
>> +int
>> +virNetlinkNewLink(const int *ifindex,
>> + const char *ifname,
>> + const virMacAddr *mac,
>> + const char *type,
>> + virNetlinkNewLinkCallback cb,
>> + const void *opaque,
>> + int *error)
>> +{
>> + struct nlmsgerr *err;
>> + struct nlattr *linkinfo;
>> + unsigned int buflen;
>> + struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
>> + VIR_AUTOPTR(virNetlinkMsg) nl_msg = NULL;
>> + VIR_AUTOFREE(struct nlmsghdr *) resp = NULL;
>> +
>> + *error = 0;
>> +
>> + nl_msg = nlmsg_alloc_simple(RTM_NEWLINK,
>> + NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL);
>> + if (!nl_msg) {
>> + virReportOOMError();
>> + return -1;
>> + }
>> +
>> + if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) <
0)
>> + goto buffer_too_small;
>> +
>
No offence. Let me try talking about nla_put* in comment_block.
><comment_block>
>
>> + if (ifindex && nla_put_u32(nl_msg, IFLA_LINK, *ifindex) < 0)
>
>pre-existing, but is there a particular reason why ^this has to be u32??
prototype of nla_put_u32:
int nla_put_u32(struct nl_msg *msg, int attrtype, uint32_t value);
It is used for adding 32 bit integer into msg.
We got ifindex by calling ioctl with SIOCGIFINDEX and this ifindex >= 0.
So I think that it's right to use nla_put_u32.
>
>> + goto buffer_too_small;
>> +
>> + if (mac && nla_put(nl_msg, IFLA_ADDRESS, VIR_MAC_BUFLEN, mac) <
0)
>> + goto buffer_too_small;
>
>Similarly, is there a reason why ^this is not necessary to be u32?
This was a brain fart too, of course it wouldn't work because we're not
adding an int here, so you're right.
prototype of nla_put:
int nla_put(struct nl_msg *msg, int attrtype, int datalen, const void *data);
It means put a sequence of octets into msg. It could be used for string and
other packed struct.
The type of mac is struct virMacAddr which size is VIR_MAC_BUFLEN.
So I think it's right.
>
>> +
>> + if (ifname && nla_put(nl_msg, IFLA_IFNAME, strlen(ifname)+1,
ifname) < 0)
>> + goto buffer_too_small;
>> +
>> + if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO)))
>
>Since we're already touching the code, I would find it more readable if ^this
>was written as linkinfo = nla_nest_start. The reason for that is that it's not
>immediately visible where the matching counterpart to "nla_nest_end" is.
Okay.
>
>> + goto buffer_too_small;
>> +
>> + if (nla_put(nl_msg, IFLA_INFO_KIND, strlen(type), type) < 0)
>
>I'm puzzled why ^this doesn't need strlen(foo)+1 instead of plain
strlen(foo)
This code is same as iproute2. There's no problem here.
In net/core/rtnetlink.c of kernel (source v4.4.0):
nla_strlcpy(kind, linkinfo[IFLA_INFO_KIND], sizeof(kind));
and the implementation of nla_strlcpy:
size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
{
size_t srclen = nla_len(nla); /* whatever it is strlen(foo)+1 or strlen(foo)
*/
char *src = nla_data(nla);
=> if (srclen > 0 && src[srclen - 1] == '\0')
=> srclen--;
But I think it should always be strlen(foo)+1 for consistency of code.
It's also safer, because that way you're always sure that you're getting a
nul-terminated string, especially since you'll be doing a plain memcpy in
nla_put + you'll avoid questions like mine out of sheer confusion.
>
>> + goto buffer_too_small;
>
></comment_block>
>
>We could actually create a wrapper macro around nla_put which would make the
>block (begin-end) tiny more readable. See my notes above, as I have further
>questions...Now, the macros would again be a separate patch to make the change
>more gradual. Depending on the comments to my questions above, the macro would
>either take the size of the type and always call nla_put or a specialized
>nla_put_<string|u32|whatever> function. I'm CC'ing Laine to help
answering my
>questions inside <comment_block>.
>
>Erik
I think that the usage of nla_put* is clear now.
So I don't know how to create wrapper macros.
Could you give me some instructions for it?
Currently what I have on my branch is the following (more changes needed to
actually compile it):
diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c
index 817e347cec..e626d53a31 100644
--- a/src/util/virnetlink.c
+++ b/src/util/virnetlink.c
@@ -515,12 +515,25 @@ virNetlinkNewLink(const int *ifindex,
int *error)
{
struct nlmsgerr *err;
- struct nlattr *linkinfo;
unsigned int buflen;
struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
+ struct nlattr *linkinfo = NULL;
+ struct nlattr *info_data = NULL;
VIR_AUTOPTR(virNetlinkMsg) nl_msg = NULL;
VIR_AUTOFREE(struct nlmsghdr *) resp = NULL;
+# define NETLINK_MSG_NEST_START(container, attrtype) \
+ container = nla_nest_start(nl_msg, attrtype); \
+ if (!container) \
+ goto buffer_too_small;
+
+# define NETLINK_MSG_NEST_END(container) \
+ nla_nest_end(nl_msg, container);
+
+# define NETLINK_MSG_PUT(attrtype, datalen, data) \
+ if (data && nla_put(nl_msg, attrtype, datalen, data) < 0) \
+ goto buffer_too_small;
+
*error = 0;
nl_msg = nlmsg_alloc_simple(RTM_NEWLINK,
@@ -533,25 +546,24 @@ virNetlinkNewLink(const int *ifindex,
if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0)
goto buffer_too_small;
- if (ifindex && nla_put_u32(nl_msg, IFLA_LINK, *ifindex) < 0)
- goto buffer_too_small;
+ NETLINK_MSG_PUT(IFLA_LINK, sizeof(uint32_t), ifindex)
+ NETLINK_MSG_PUT(IFLA_ADDRESS, VIR_MAC_BUFLEN, mac)
+ NETLINK_MSG_PUT(IFLA_IFNAME, (strlen(ifname)+1), ifname)
- if (mac && nla_put(nl_msg, IFLA_ADDRESS, VIR_MAC_BUFLEN, mac) < 0)
- goto buffer_too_small;
+ NETLINK_MSG_NEST_START(linkinfo, IFLA_LINKINFO)
- if (ifname && nla_put(nl_msg, IFLA_IFNAME, strlen(ifname)+1, ifname) < 0)
- goto buffer_too_small;
+ NETLINK_MSG_PUT(IFLA_INFO_KIND, (strlen(type)+1), type)
- if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO)))
- goto buffer_too_small;
+ if ((STREQ(type, "macvtap") || STREQ(type, "macvlan"))
&&
+ macvlan_mode && *macvlan_mode > 0) {
+ NETLINK_MSG_NEST_START(info_data, IFLA_INFO_DATA)
- if (nla_put(nl_msg, IFLA_INFO_KIND, strlen(type), type) < 0)
- goto buffer_too_small;
+ NETLINK_MSG_PUT(IFLA_MACVLAN_MODE, sizeof(uint32_t), macvlan_mode)
- if (cb && cb(nl_msg, opaque) < 0)
- return -1;
+ NETLINK_MSG_NEST_END(info_data)
+ }
- nla_nest_end(nl_msg, linkinfo);
+ NETLINK_MSG_NEST_END(linkinfo)
if (virNetlinkCommand(nl_msg, &resp, &buflen, 0, 0, NETLINK_ROUTE, 0) <
0)
return -1;
@@ -578,6 +590,10 @@ virNetlinkNewLink(const int *ifindex,
goto malformed_resp;
}
+# undef NETLINK_MSG_NEST_START
+# undef NETLINK_MSG_NEST_END
+# undef NETLINK_MSG_PUT
+
return 0;
malformed_resp:
Regards,
Erik
11:37 p.m.
On 2018-08-31 at 20:02, Erik Skultety wrote:
On Thu, Aug 30, 2018 at 02:27:05PM +0800, Shi Lei wrote:
> Thanks for your comments.
> But I have several questions, please see below...
>
> On 2018-08-29 at 19:43, Erik Skultety wrote:
> >On Thu, Aug 23, 2018 at 12:15:08PM +0800, Shi Lei wrote:
> >> This patch adds virNetlinkNewLink for simplifying virNetDevMacVLanCreate
> >> and virNetDevBridgeCreate.
> >>
> >> Signed-off-by: Shi Lei <shi_lei(a)massclouds.com>
> >> ---
> >
> >There are multiple changes happening in this patch so it will need to be split
> >into several patches, see below...
>
> Okay. Then the v2 series should be like:
> [patch v2 0/4]: ... cover ...
> [patch v2 1/4]: Add wrapper macros to make code more readable
> [patch v2 2/4]: Introduce virNetlinkNewLink
2/4 would come before 1/4
Okay.
> [patch v2 3/4]: Replace the implementation of virNetDevBridgeCreate
> [patch v2 4/4]: Replace the implementation of virNetDevMacVLanCreate
3/4 + 4/4 would be a single patch
Okay.
...
> >> +static int
> >> +virNetDevMacVLanCreateCallback(struct nl_msg *nl_msg, const void *opaque)
> >> +{
> >> + const uint32_t *mode = (const uint32_t *) opaque;
> >> + if (!nl_msg || !opaque) {
> >> + virReportError(VIR_ERR_INTERNAL_ERROR,
> >> + _("nl_msg %p or opaque %p is NULL"),
> >> + nl_msg, opaque);
> >> + return -1;
> >> + }
> >> +
> >> + if (*mode > 0) {
> >> + struct nlattr *info_data;
> >> + if (!(info_data = nla_nest_start(nl_msg, IFLA_INFO_DATA)))
> >> + goto buffer_too_small;
> >> +
> >> + if (nla_put(nl_msg, IFLA_MACVLAN_MODE, sizeof(*mode), mode) <
0)
> >> + goto buffer_too_small;
> >> +
> >> + nla_nest_end(nl_msg, info_data);
> >> + }
> >> +
> >> + return 0;
> >> +
> >> + buffer_too_small:
> >> + virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> >> + _("allocated netlink buffer is too small"));
> >> + return -1;
> >> +}
> >
> >Having a callback just to add a nested data into nl_msg doesn't feel like
the
> >right approach, I'd expect a callback to do more specific stuff, this should
be
> >special-cased in virNetlinkNewLink.
>
> I looked through the code for ip-link in iproute2 which could be a good example
> for netlink. And I found that the differences of attributes of various net-devices
are
> confined to IFLA_INFO_DATA or IFLA_INFO_SLAVE_DATA(this is not used in libvirt).
> The code fragment in iplink.c:
>
> if (ulinep && !strcmp(ulinep, "_slave")) {
> ... ...
> lu = get_link_slave_kind(slavebuf);
> iflatype = IFLA_INFO_SLAVE_DATA;
> } else {
> => lu = get_link_kind(type); /* Get pointer to the driver for
this type */
> => iflatype = IFLA_INFO_DATA; /* NEST will be for IFLA_INFO_DATA */
> }
> if (lu && argc) {
> => struct rtattr *data = addattr_nest(&req.n, sizeof(req), iflatype);
/* NEST BEGIN */
>
> ****************************
> if (lu->parse_opt &&
> lu->parse_opt(lu, argc, argv, &req.n))
> return -1;
> ****************************
> ^The lu points to various types of net-drivers(e.g.
macvlan/bridge/vxlan/vlan ...)
> which pack all special self-attributes in their parse_opt callback
>
> => addattr_nest_end(&req.n, data); /* NEST END */
>
> So I think that it's reasonable for us to have a callback to handle it just as
iproute2
> since iproute2 could almost create all the types of net-devices.
I went through the iproute2 code and it completely makes sense for them to
utilize callbacks here, given the amount of driver-specific options each of the
device type has. While I agree that we could make use of this in libvirt one
day, I don't feel like we need to do it now, since I don't think it brings
any noticeable benefit in its currently proposed form + as I already mentioned,
we can switch to this scheme once there are more than 1 netlink types which
could make use of it.
Okay.
>
> >
> >> +
> >> +
> >> /**
> >> * virNetDevMacVLanCreate:
> >> *
> >> @@ -307,113 +338,29 @@ virNetDevMacVLanCreate(const char *ifname,
> >> uint32_t macvlan_mode,
> >> int *retry)
> >> {
> >
> >^This replacement would be the last patch in the series.
>
> Okay.
>
> >
> >> - int rc = -1;
> >> - struct nlmsgerr *err;
> >> - struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
> >> int ifindex;
> >> - unsigned int recvbuflen;
> >> - struct nl_msg *nl_msg;
> >> - struct nlattr *linkinfo, *info_data;
> >> - char macstr[VIR_MAC_STRING_BUFLEN];
> >> - VIR_AUTOFREE(struct nlmsghdr *) resp = NULL;
> >> -
> >> - if (virNetDevGetIndex(srcdev, &ifindex) < 0)
> >> - return -1;
> >> -
> >> + int error = 0;
> >> *retry = 0;
> >>
> >> - nl_msg = nlmsg_alloc_simple(RTM_NEWLINK,
> >> - NLM_F_REQUEST | NLM_F_CREATE |
NLM_F_EXCL);
> >> - if (!nl_msg) {
> >> - virReportOOMError();
> >> + if (virNetDevGetIndex(srcdev, &ifindex) < 0)
> >> return -1;
> >> - }
> >> -
> >> - if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO)
< 0)
> >> - goto buffer_too_small;
> >> -
> >> - if (nla_put_u32(nl_msg, IFLA_LINK, ifindex) < 0)
> >> - goto buffer_too_small;
> >> -
> >> - if (nla_put(nl_msg, IFLA_ADDRESS, VIR_MAC_BUFLEN, macaddress) < 0)
> >> - goto buffer_too_small;
> >> -
> >> - if (ifname &&
> >> - nla_put(nl_msg, IFLA_IFNAME, strlen(ifname)+1, ifname) < 0)
> >> - goto buffer_too_small;
> >>
> >> - if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO)))
> >> - goto buffer_too_small;
> >> -
> >> - if (nla_put(nl_msg, IFLA_INFO_KIND, strlen(type), type) < 0)
> >> - goto buffer_too_small;
> >> -
> >> - if (macvlan_mode > 0) {
> >> - if (!(info_data = nla_nest_start(nl_msg, IFLA_INFO_DATA)))
> >> - goto buffer_too_small;
> >> -
> >> - if (nla_put(nl_msg, IFLA_MACVLAN_MODE, sizeof(macvlan_mode),
> >> - &macvlan_mode) < 0)
> >> - goto buffer_too_small;
> >> -
> >> - nla_nest_end(nl_msg, info_data);
> >> - }
> >> -
> >> - nla_nest_end(nl_msg, linkinfo);
> >> -
> >> - if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, 0, 0,
> >> - NETLINK_ROUTE, 0) < 0) {
> >> - goto cleanup;
> >> - }
> >> -
> >> - if (recvbuflen < NLMSG_LENGTH(0) || resp == NULL)
> >> - goto malformed_resp;
> >> -
> >> - switch (resp->nlmsg_type) {
> >> - case NLMSG_ERROR:
> >> - err = (struct nlmsgerr *)NLMSG_DATA(resp);
> >> - if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err)))
> >> - goto malformed_resp;
> >> -
> >> - switch (err->error) {
> >> -
> >> - case 0:
> >> - break;
> >> -
> >> - case -EEXIST:
> >> + if (virNetlinkNewLink(&ifindex, ifname, macaddress, type,
> >> + virNetDevMacVLanCreateCallback,
&macvlan_mode,
> >> + &error) < 0) {
> >> + char macstr[VIR_MAC_STRING_BUFLEN];
> >> + if (error == -EEXIST)
> >> *retry = 1;
> >> - goto cleanup;
> >> -
> >> - default:
> >> - virReportSystemError(-err->error,
> >> + else
> >> + virReportSystemError(-error,
> >> _("error creating %s interface %s@%s
(%s)"),
> >> type, ifname, srcdev,
> >> virMacAddrFormat(macaddress, macstr));
> >> - goto cleanup;
> >> - }
> >> - break;
> >> -
> >> - case NLMSG_DONE:
> >> - break;
> >>
> >> - default:
> >> - goto malformed_resp;
> >> + return -1;
> >> }
> >>
> >> - rc = 0;
> >> - cleanup:
> >> - nlmsg_free(nl_msg);
> >> - return rc;
> >> -
> >> - malformed_resp:
> >> - virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> >> - _("malformed netlink response message"));
> >> - goto cleanup;
> >> -
> >> - buffer_too_small:
> >> - virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> >> - _("allocated netlink buffer is too small"));
> >> - goto cleanup;
> >> + return 0;
> >> }
> >>
> >> /**
> >> diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c
> >> index 8f06446..817e347 100644
> >> --- a/src/util/virnetlink.c
> >> +++ b/src/util/virnetlink.c
> >> @@ -489,6 +489,110 @@ virNetlinkDumpLink(const char *ifname, int ifindex,
> >>
> >>
> >> /**
> >> + * virNetlinkNewLink:
> >
> >Introduction of this function should come in a separate patch before you start
> >replacing the existing ones.
>
> Okay.
>
> >
> >> + *
> >> + * @ifindex: The index for the 'link' device
> >> + * @ifname: The name of the link
> >> + * @mac: The MAC address of the device
> >
> >Most of ^these attributes could be packed into a virNetlinkNewLinkData
> >structure (or something similarly named). You'll have to test check for
> >VIR_DOMAIN_NET_TYPE_DIRECT and VIR_NETDEV_MACVLAN_MODE_VEPA according to my
> >comments below inside <comment_block>...
>
> I have studied your comments inside <comment_block>, but I still don't know
how to
> test check for VIR_DOMAIN_NET_TYPE_DIRECT and VIR_NETDEV_MACVLAN_MODE_VEPA.
> Could you explain it for me? :-)
Actually, I retract on checking the modes ^this way, I was hasty with my
response and then went through the code more thoroughly and realized that mode
corresponds to netlink modes rather than to libvirt MACVLAN_MODE_X and we have
a corresponding modemap for this. Not that it could not be achieved with our
enums, but it's just not worth passing it around, so we'll need to imo rely on
the @type string, which in this case would either be "macvtap" or
"macvlan".
Okay.
>
> >
> >> + * @type: The type of device, i.e., "bridge",
"macvtap", "macvlan"
> >> + * @cb: The callback for filling in IFLA_INFO_DATA for this type
> >
> >I don't think callback will be necessary
>
> I think that it's reasonable to use callback here.
> Another mode might be:
> 1) pre-alloc buffer and fill in IFLA_INFO_DATA
> 2) pass the buffer pointer as a param into virNetlinkNewLink which will
> embed it into nlmsg
> 3) free the buffer
> I think that this mode might be a bit more complicated and it's hard to find good
references.
>
> >
> >> + * @opaque: opaque for the callback
> >> + * @error: for retrieving error code
> >
> >^see below for my comment on return value...
>
> Okay.
>
> >
> >> + *
> >> + * Create a network "link" (aka interface aka device) with the
given
> >> + * args. This works for many different types of network devices,
> >> + * including macvtap and bridges.
> >> + *
> >> + * Returns 0 on success, -1 on fatal error.
> >
<brain fart>
> >Since this is a nice libvirt wrapper around the netlink communication
> >machinery, I think that returning -<netlink_error> in case of an error is
> >reasonable. Then, each of the callers of this API can handle the return values
> >as they please.
<brain fart/>
>
> Okay. I will use netlink error as return-value.
> But how to handle -1?
> 1) always return -1 for *other* failures
> 2) return -ENOMEM for OutofMemory; return -ENOBUFS for buffer_too_small; ...
Good point, we couldn't differentiate between -1 from libvirt and -ENOPERM or
-NLE_FAILURE (from libnl), so the @error variable should stay.
Okay.
> I should take which one?
>
> >
> >> + */
> >> +int
> >> +virNetlinkNewLink(const int *ifindex,
> >> + const char *ifname,
> >> + const virMacAddr *mac,
> >> + const char *type,
> >> + virNetlinkNewLinkCallback cb,
> >> + const void *opaque,
> >> + int *error)
> >> +{
> >> + struct nlmsgerr *err;
> >> + struct nlattr *linkinfo;
> >> + unsigned int buflen;
> >> + struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
> >> + VIR_AUTOPTR(virNetlinkMsg) nl_msg = NULL;
> >> + VIR_AUTOFREE(struct nlmsghdr *) resp = NULL;
> >> +
> >> + *error = 0;
> >> +
> >> + nl_msg = nlmsg_alloc_simple(RTM_NEWLINK,
> >> + NLM_F_REQUEST | NLM_F_CREATE |
NLM_F_EXCL);
> >> + if (!nl_msg) {
> >> + virReportOOMError();
> >> + return -1;
> >> + }
> >> +
> >> + if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO)
< 0)
> >> + goto buffer_too_small;
> >> +
> >
>
> No offence. Let me try talking about nla_put* in comment_block.
>
> ><comment_block>
> >
> >> + if (ifindex && nla_put_u32(nl_msg, IFLA_LINK, *ifindex) <
0)
> >
> >pre-existing, but is there a particular reason why ^this has to be u32??
>
> prototype of nla_put_u32:
> int nla_put_u32(struct nl_msg *msg, int attrtype, uint32_t value);
> It is used for adding 32 bit integer into msg.
> We got ifindex by calling ioctl with SIOCGIFINDEX and this ifindex >= 0.
> So I think that it's right to use nla_put_u32.
>
> >
> >> + goto buffer_too_small;
> >> +
> >> + if (mac && nla_put(nl_msg, IFLA_ADDRESS, VIR_MAC_BUFLEN, mac)
< 0)
> >> + goto buffer_too_small;
> >
> >Similarly, is there a reason why ^this is not necessary to be u32?
This was a brain fart too, of course it wouldn't work because we're not
adding an int here, so you're right.
Okay.
>
> prototype of nla_put:
> int nla_put(struct nl_msg *msg, int attrtype, int datalen, const void *data);
> It means put a sequence of octets into msg. It could be used for string and
> other packed struct.
> The type of mac is struct virMacAddr which size is VIR_MAC_BUFLEN.
> So I think it's right.
>
> >
> >> +
> >> + if (ifname && nla_put(nl_msg, IFLA_IFNAME, strlen(ifname)+1,
ifname) < 0)
> >> + goto buffer_too_small;
> >> +
> >> + if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO)))
> >
> >Since we're already touching the code, I would find it more readable if
^this
> >was written as linkinfo = nla_nest_start. The reason for that is that it's
not
> >immediately visible where the matching counterpart to "nla_nest_end"
is.
>
> Okay.
>
> >
> >> + goto buffer_too_small;
> >> +
> >> + if (nla_put(nl_msg, IFLA_INFO_KIND, strlen(type), type) < 0)
> >
> >I'm puzzled why ^this doesn't need strlen(foo)+1 instead of plain
strlen(foo)
>
> This code is same as iproute2. There's no problem here.
> In net/core/rtnetlink.c of kernel (source v4.4.0):
> nla_strlcpy(kind, linkinfo[IFLA_INFO_KIND], sizeof(kind));
> and the implementation of nla_strlcpy:
> size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
> {
> size_t srclen = nla_len(nla); /* whatever it is strlen(foo)+1 or
strlen(foo) */
> char *src = nla_data(nla);
> => if (srclen > 0 && src[srclen - 1] == '\0')
> => srclen--;
>
> But I think it should always be strlen(foo)+1 for consistency of code.
It's also safer, because that way you're always sure that you're getting a
nul-terminated string, especially since you'll be doing a plain memcpy in
nla_put + you'll avoid questions like mine out of sheer confusion.
Okay.
>
> >
> >> + goto buffer_too_small;
> >
> ></comment_block>
> >
> >We could actually create a wrapper macro around nla_put which would make the
> >block (begin-end) tiny more readable. See my notes above, as I have further
> >questions...Now, the macros would again be a separate patch to make the change
> >more gradual. Depending on the comments to my questions above, the macro would
> >either take the size of the type and always call nla_put or a specialized
> >nla_put_<string|u32|whatever> function. I'm CC'ing Laine to help
answering my
> >questions inside <comment_block>.
> >
> >Erik
>
> I think that the usage of nla_put* is clear now.
> So I don't know how to create wrapper macros.
> Could you give me some instructions for it?
Currently what I have on my branch is the following (more changes needed to
actually compile it):
diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c
index 817e347cec..e626d53a31 100644
--- a/src/util/virnetlink.c
+++ b/src/util/virnetlink.c
@@ -515,12 +515,25 @@ virNetlinkNewLink(const int *ifindex,
int *error)
{
struct nlmsgerr *err;
- struct nlattr *linkinfo;
unsigned int buflen;
struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
+ struct nlattr *linkinfo = NULL;
+ struct nlattr *info_data = NULL;
VIR_AUTOPTR(virNetlinkMsg) nl_msg = NULL;
VIR_AUTOFREE(struct nlmsghdr *) resp = NULL;
+# define NETLINK_MSG_NEST_START(container, attrtype) \
+ container = nla_nest_start(nl_msg, attrtype); \
+ if (!container) \
+ goto buffer_too_small;
+
+# define NETLINK_MSG_NEST_END(container) \
+ nla_nest_end(nl_msg, container);
+
+# define NETLINK_MSG_PUT(attrtype, datalen, data) \
+ if (data && nla_put(nl_msg, attrtype, datalen, data) < 0) \
+ goto buffer_too_small;
+
*error = 0;
nl_msg = nlmsg_alloc_simple(RTM_NEWLINK,
@@ -533,25 +546,24 @@ virNetlinkNewLink(const int *ifindex,
if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0)
goto buffer_too_small;
- if (ifindex && nla_put_u32(nl_msg, IFLA_LINK, *ifindex) < 0)
- goto buffer_too_small;
+ NETLINK_MSG_PUT(IFLA_LINK, sizeof(uint32_t), ifindex)
+ NETLINK_MSG_PUT(IFLA_ADDRESS, VIR_MAC_BUFLEN, mac)
+ NETLINK_MSG_PUT(IFLA_IFNAME, (strlen(ifname)+1), ifname)
- if (mac && nla_put(nl_msg, IFLA_ADDRESS, VIR_MAC_BUFLEN, mac) < 0)
- goto buffer_too_small;
+ NETLINK_MSG_NEST_START(linkinfo, IFLA_LINKINFO)
- if (ifname && nla_put(nl_msg, IFLA_IFNAME, strlen(ifname)+1, ifname) < 0)
- goto buffer_too_small;
+ NETLINK_MSG_PUT(IFLA_INFO_KIND, (strlen(type)+1), type)
- if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO)))
- goto buffer_too_small;
+ if ((STREQ(type, "macvtap") || STREQ(type, "macvlan"))
&&
+ macvlan_mode && *macvlan_mode > 0) {
+ NETLINK_MSG_NEST_START(info_data, IFLA_INFO_DATA)
- if (nla_put(nl_msg, IFLA_INFO_KIND, strlen(type), type) < 0)
- goto buffer_too_small;
+ NETLINK_MSG_PUT(IFLA_MACVLAN_MODE, sizeof(uint32_t), macvlan_mode)
- if (cb && cb(nl_msg, opaque) < 0)
- return -1;
+ NETLINK_MSG_NEST_END(info_data)
+ }
- nla_nest_end(nl_msg, linkinfo);
+ NETLINK_MSG_NEST_END(linkinfo)
if (virNetlinkCommand(nl_msg, &resp, &buflen, 0, 0, NETLINK_ROUTE, 0) <
0)
return -1;
@@ -578,6 +590,10 @@ virNetlinkNewLink(const int *ifindex,
goto malformed_resp;
}
+# undef NETLINK_MSG_NEST_START
+# undef NETLINK_MSG_NEST_END
+# undef NETLINK_MSG_PUT
+
return 0;
malformed_resp:
Regards,
Erik
I got it! Thanks.
Shi Lei
2523
days inactive
2533
days old
4 comments
2 participants
participants (2)
-
Erik Skultety -
Shi Lei