netlink: Introduce a helper function to simplify netlink functions

Extract common code as helper function virNetlinkTalk, then simplify
the functions virNetlink[DumpLink|NewLink|DelLink|GetNeighbor].

Signed-off-by: Shi Lei <shi_lei@massclouds.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
This commit is contained in:
Shi Lei 2021-01-11 10:23:37 +08:00 committed by Michal Privoznik
parent 871eba4d99
commit 037ea5d10c
2 changed files with 129 additions and 135 deletions

View File

@ -353,6 +353,82 @@ int virNetlinkCommand(struct nl_msg *nl_msg,
return 0;
}
/**
* virNetlinkTalk:
* @ifname: name of the link
* @nl_msg: pointer to netlink message
* @src_pid: pid used for nl_pid of the local end of the netlink message
* (0 == "use getpid()")
* @dst_pid: pid of destination nl_pid if the kernel
* is not the target of the netlink message but it is to be
* sent to another process (0 if sending to the kernel)
* @resp: pointer to pointer where response buffer will be allocated
* @resp_len: pointer to integer holding the size of the response buffer
* on return of the function
* @error: pointer to store netlink error (-errno)
* @fallback: pointer to an alternate function that will be called in case
* netlink fails with EOPNOTSUPP (any other error will simply be
* treated as an error)
*
* Simple wrapper around virNetlinkCommand(). The returned netlink message
* is allocated at @resp. Please note that according to netlink(7) man page,
* reply with type of NLMSG_ERROR and @error == 0 is an acknowledgment and
* thus not an error.
*
* Returns: 0 on success,
* -1 otherwise (error reported if @error == NULL)
*/
static int
virNetlinkTalk(const char *ifname,
virNetlinkMsg *nl_msg,
uint32_t src_pid,
uint32_t dst_pid,
struct nlmsghdr **resp,
unsigned int *resp_len,
int *error,
virNetlinkTalkFallback fallback)
{
if (virNetlinkCommand(nl_msg, resp, resp_len,
src_pid, dst_pid, NETLINK_ROUTE, 0) < 0)
return -1;
if (*resp_len < NLMSG_LENGTH(0) || *resp == NULL)
goto malformed_resp;
if ((*resp)->nlmsg_type == NLMSG_ERROR) {
struct nlmsgerr *err;
err = (struct nlmsgerr *) NLMSG_DATA(*resp);
if ((*resp)->nlmsg_len < NLMSG_LENGTH(sizeof(*err)))
goto malformed_resp;
if (-err->error == EOPNOTSUPP && fallback)
return fallback(ifname);
if (err->error < 0) {
if (error)
*error = err->error;
else
virReportSystemError(-err->error, "%s", _("netlink error"));
return -1;
}
/* According to netlink(7) man page NLMSG_ERROR packet with error
* field set to 0 is an acknowledgment packet and thus not an error. */
}
return 0;
malformed_resp:
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("malformed netlink response message"));
return -1;
}
int
virNetlinkDumpCommand(struct nl_msg *nl_msg,
virNetlinkDumpCallback callback,
@ -396,6 +472,7 @@ virNetlinkDumpCommand(struct nl_msg *nl_msg,
return 0;
}
/**
* virNetlinkDumpLink:
*
@ -420,15 +497,14 @@ virNetlinkDumpLink(const char *ifname, int ifindex,
void **nlData, struct nlattr **tb,
uint32_t src_pid, uint32_t dst_pid)
{
int rc = -1;
struct nlmsgerr *err;
struct ifinfomsg ifinfo = {
.ifi_family = AF_UNSPEC,
.ifi_index = ifindex
};
unsigned int recvbuflen;
g_autoptr(virNetlinkMsg) nl_msg = NULL;
g_autofree struct nlmsghdr *resp = NULL;
unsigned int resp_len = 0;
int error = 0;
if (ifname && ifindex <= 0 && virNetDevGetIndex(ifname, &ifindex) < 0)
return -1;
@ -459,46 +535,25 @@ virNetlinkDumpLink(const char *ifname, int ifindex,
}
# endif
if (virNetlinkCommand(nl_msg, &resp, &recvbuflen,
src_pid, dst_pid, NETLINK_ROUTE, 0) < 0)
if (virNetlinkTalk(ifname, nl_msg, src_pid, dst_pid,
&resp, &resp_len, &error, NULL) < 0) {
virReportSystemError(-error,
_("error dumping %s (%d) interface"),
ifname, ifindex);
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) {
virReportSystemError(-err->error,
_("error dumping %s (%d) interface"),
ifname, ifindex);
return -1;
}
break;
case GENL_ID_CTRL:
case NLMSG_DONE:
rc = nlmsg_parse(resp, sizeof(struct ifinfomsg),
tb, IFLA_MAX, NULL);
if (rc < 0)
goto malformed_resp;
break;
default:
goto malformed_resp;
if ((resp->nlmsg_type != NLMSG_ERROR &&
resp->nlmsg_type != GENL_ID_CTRL &&
resp->nlmsg_type != NLMSG_DONE) ||
nlmsg_parse(resp, sizeof(struct ifinfomsg), tb, IFLA_MAX, NULL) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("malformed netlink response message"));
return -1;
}
*nlData = g_steal_pointer(&resp);
return 0;
malformed_resp:
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("malformed netlink response message"));
return rc;
}
@ -523,13 +578,12 @@ virNetlinkNewLink(const char *ifname,
virNetlinkNewLinkDataPtr extra_args,
int *error)
{
struct nlmsgerr *err;
struct nlattr *linkinfo = NULL;
struct nlattr *infodata = NULL;
unsigned int buflen;
struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
g_autoptr(virNetlinkMsg) nl_msg = NULL;
g_autofree struct nlmsghdr *resp = NULL;
unsigned int resp_len = 0;
*error = 0;
@ -591,37 +645,18 @@ virNetlinkNewLink(const char *ifname,
}
}
if (virNetlinkCommand(nl_msg, &resp, &buflen, 0, 0, NETLINK_ROUTE, 0) < 0)
if (virNetlinkTalk(ifname, nl_msg, 0, 0,
&resp, &resp_len, error, NULL) < 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;
if (resp->nlmsg_type != NLMSG_ERROR &&
resp->nlmsg_type != NLMSG_DONE) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("malformed netlink response message"));
return -1;
}
return 0;
malformed_resp:
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("malformed netlink response message"));
return -1;
}
@ -641,13 +676,13 @@ virNetlinkNewLink(const char *ifname,
* Returns 0 on success, -1 on fatal error.
*/
int
virNetlinkDelLink(const char *ifname, virNetlinkDelLinkFallback fallback)
virNetlinkDelLink(const char *ifname, virNetlinkTalkFallback fallback)
{
struct nlmsgerr *err;
struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC };
unsigned int recvbuflen;
g_autoptr(virNetlinkMsg) nl_msg = NULL;
g_autofree struct nlmsghdr *resp = NULL;
unsigned int resp_len = 0;
int error = 0;
nl_msg = nlmsg_alloc_simple(RTM_DELLINK, NLM_F_REQUEST);
if (!nl_msg) {
@ -659,44 +694,22 @@ virNetlinkDelLink(const char *ifname, virNetlinkDelLinkFallback fallback)
NETLINK_MSG_PUT(nl_msg, IFLA_IFNAME, (strlen(ifname) + 1), ifname);
if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, 0, 0,
NETLINK_ROUTE, 0) < 0) {
if (virNetlinkTalk(ifname, nl_msg, 0, 0,
&resp, &resp_len, &error, fallback) < 0) {
virReportSystemError(-error,
_("error destroying network device %s"),
ifname);
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 == EOPNOTSUPP && fallback)
return fallback(ifname);
if (err->error) {
virReportSystemError(-err->error,
_("error destroying network device %s"),
ifname);
return -1;
}
break;
case NLMSG_DONE:
break;
default:
goto malformed_resp;
if (resp->nlmsg_type != NLMSG_ERROR &&
resp->nlmsg_type != NLMSG_DONE) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("malformed netlink response message"));
return -1;
}
return 0;
malformed_resp:
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("malformed netlink response message"));
return -1;
}
/**
@ -712,18 +725,18 @@ virNetlinkDelLink(const char *ifname, virNetlinkDelLinkFallback fallback)
*
* Get neighbor table entry from netlink.
*
* Returns 0 on success, -1 on fatal error.
* Returns length of the raw data from netlink on success, -1 on fatal error.
*/
int
virNetlinkGetNeighbor(void **nlData, uint32_t src_pid, uint32_t dst_pid)
{
struct nlmsgerr *err;
struct ndmsg ndinfo = {
.ndm_family = AF_UNSPEC,
};
unsigned int recvbuflen;
g_autoptr(virNetlinkMsg) nl_msg = NULL;
g_autofree struct nlmsghdr *resp = NULL;
unsigned int resp_len = 0;
int error = 0;
nl_msg = nlmsg_alloc_simple(RTM_GETNEIGH, NLM_F_DUMP | NLM_F_REQUEST);
if (!nl_msg) {
@ -733,40 +746,21 @@ virNetlinkGetNeighbor(void **nlData, uint32_t src_pid, uint32_t dst_pid)
NETLINK_MSG_APPEND(nl_msg, sizeof(ndinfo), &ndinfo);
if (virNetlinkCommand(nl_msg, &resp, &recvbuflen,
src_pid, dst_pid, NETLINK_ROUTE, 0) < 0)
if (virNetlinkTalk(NULL, nl_msg, src_pid, dst_pid,
&resp, &resp_len, &error, NULL) < 0) {
virReportSystemError(-error, "%s", _("error dumping neighbor table"));
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) {
virReportSystemError(-err->error,
"%s", _("error dumping"));
return -1;
}
break;
case RTM_NEWNEIGH:
break;
default:
goto malformed_resp;
if (resp->nlmsg_type != NLMSG_ERROR &&
resp->nlmsg_type != RTM_NEWNEIGH) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("malformed netlink response message"));
return -1;
}
*nlData = g_steal_pointer(&resp);
return recvbuflen;
malformed_resp:
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("malformed netlink response message"));
return -1;
return resp_len;
}
int
@ -1300,7 +1294,7 @@ virNetlinkDumpLink(const char *ifname G_GNUC_UNUSED,
int
virNetlinkDelLink(const char *ifname G_GNUC_UNUSED,
virNetlinkDelLinkFallback fallback G_GNUC_UNUSED)
virNetlinkTalkFallback fallback G_GNUC_UNUSED)
{
virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _(unsupported));
return -1;

View File

@ -69,9 +69,9 @@ int virNetlinkNewLink(const char *ifname,
virNetlinkNewLinkDataPtr data,
int *error);
typedef int (*virNetlinkDelLinkFallback)(const char *ifname);
typedef int (*virNetlinkTalkFallback)(const char *ifname);
int virNetlinkDelLink(const char *ifname, virNetlinkDelLinkFallback fallback);
int virNetlinkDelLink(const char *ifname, virNetlinkTalkFallback fallback);
int virNetlinkGetErrorCode(struct nlmsghdr *resp, unsigned int recvbuflen);