lib: fix binding to a vrf

There are two possible use-cases for the `vrf_bind` function:
- bind socket to an interface in a vrf
- bind socket to a vrf device

For the former case, there's one problem - success is returned when the
interface is not found. In that case, the socket is left unbound without
throwing an error.

For the latter case, there are multiple possible problems:
- If the name is not set, then the socket is left unbound (zebra, vrrp).
- If the name is "default" and there's an interface with that name in the
  default VRF, then the socket is bound to that interface.
- In most daemons, if the router is configured before the VRF is actually
  created, we're trying to open and bind the socket right after the
  daemon receives a VRF registration from zebra. We may not receive the
  VRF-interface registration from zebra yet at that point. Therefore,
  `if_lookup_by_name` fails, and the socket is left unbound.

This commit fixes all the issues and updates the function description.

Suggested-by: Pat Ruddy <pat@voltanet.io>
Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
This commit is contained in:
Igor Ryzhov 2021-05-07 02:49:40 +03:00
parent 676847384b
commit 36eef8586d
4 changed files with 56 additions and 30 deletions

View File

@ -994,25 +994,50 @@ const char *vrf_get_default_name(void)
return vrf_default_name;
}
int vrf_bind(vrf_id_t vrf_id, int fd, const char *name)
int vrf_bind(vrf_id_t vrf_id, int fd, const char *ifname)
{
int ret = 0;
struct interface *ifp;
struct vrf *vrf;
if (fd < 0)
return -1;
if (vrf_id == VRF_UNKNOWN)
return -1;
/* can't bind to a VRF that doesn't exist */
vrf = vrf_lookup_by_id(vrf_id);
if (!vrf_is_enabled(vrf))
return -1;
if (ifname && strcmp(ifname, vrf->name)) {
/* binding to a regular interface */
/* can't bind to an interface that doesn't exist */
ifp = if_lookup_by_name(ifname, vrf_id);
if (!ifp)
return -1;
} else {
/* binding to a VRF device */
/* nothing to do for netns */
if (vrf_is_backend_netns())
return 0;
/* nothing to do for default vrf */
if (vrf_id == VRF_DEFAULT)
return 0;
ifname = vrf->name;
}
if (fd < 0 || name == NULL)
return fd;
/* the device should exist
* otherwise we should return
* case ifname = vrf in netns mode => return
*/
ifp = if_lookup_by_name(name, vrf_id);
if (!ifp)
return fd;
#ifdef SO_BINDTODEVICE
ret = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, name, strlen(name)+1);
ret = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, ifname,
strlen(ifname) + 1);
if (ret < 0)
zlog_debug("bind to interface %s failed, errno=%d", name,
errno);
zlog_err("bind to interface %s failed, errno=%d", ifname,
errno);
#endif /* SO_BINDTODEVICE */
return ret;
}

View File

@ -251,15 +251,14 @@ extern int vrf_sockunion_socket(const union sockunion *su, vrf_id_t vrf_id,
const char *name);
/*
* Binds a socket to a VRF device.
* Binds a socket to an interface (ifname) in a VRF (vrf_id).
*
* If name is null, the socket is not bound, irrespective of any other
* arguments.
* If ifname is NULL or is equal to the VRF name then bind to a VRF device.
* Otherwise, bind to the specified interface in the specified VRF.
*
* name should be the name of the VRF device. vrf_id should be the
* corresponding vrf_id (the ifindex of the device).
* Returns 0 on success and -1 on failure.
*/
extern int vrf_bind(vrf_id_t vrf_id, int fd, const char *name);
extern int vrf_bind(vrf_id_t vrf_id, int fd, const char *ifname);
/* VRF ioctl operations */
extern int vrf_getaddrinfo(const char *node, const char *service,

View File

@ -42,7 +42,7 @@ sys.path.append(os.path.join(CWD, "../"))
from lib import topotest
from lib.topogen import Topogen, TopoRouter, get_topogen
from lib.topolog import logger
from lib.common_config import adjust_router_l3mdev
from lib.common_config import required_linux_kernel_version
# Required to instantiate the topology builder class.
from mininet.topo import Topo
@ -66,6 +66,12 @@ class BGPIPV6RTADVVRFTopo(Topo):
def setup_module(mod):
"Sets up the pytest environment"
# Required linux kernel version for this suite to run.
result = required_linux_kernel_version("5.0")
if result is not True:
pytest.skip("Kernel requirements are not met")
tgen = Topogen(BGPIPV6RTADVVRFTopo, mod.__name__)
tgen.start_topology()
@ -84,9 +90,6 @@ def setup_module(mod):
for cmd in cmds:
output = tgen.net[rname].cmd(cmd.format(rname))
# adjust handling of vrf traffic
adjust_router_l3mdev(tgen, rname)
for rname, router in router_list.items():
router.load_config(
TopoRouter.RD_ZEBRA, os.path.join(CWD, "{}/zebra.conf".format(rname))

View File

@ -92,10 +92,7 @@ from lib import topotest
from lib.topogen import Topogen, TopoRouter, get_topogen
from lib.topolog import logger
from lib.topotest import iproute2_is_vrf_capable
from lib.common_config import (
required_linux_kernel_version,
adjust_router_l3mdev,
)
from lib.common_config import required_linux_kernel_version
#####################################################
##
@ -159,6 +156,11 @@ class NetworkTopo(Topo):
def setup_module(mod):
"Sets up the pytest environment"
# Required linux kernel version for this suite to run.
result = required_linux_kernel_version("5.0")
if result is not True:
pytest.skip("Kernel requirements are not met")
tgen = Topogen(NetworkTopo, mod.__name__)
tgen.start_topology()
@ -197,9 +199,6 @@ def setup_module(mod):
for cmd in cmds2:
output = tgen.net[rname].cmd(cmd.format(rname))
# adjust handling of vrf traffic
adjust_router_l3mdev(tgen, rname)
for rname, router in tgen.routers().items():
router.load_config(
TopoRouter.RD_ZEBRA, os.path.join(CWD, "{}/zebra.conf".format(rname))