diff options
Diffstat (limited to 'staslib/udev.py')
| -rw-r--r-- | staslib/udev.py | 199 |
1 files changed, 184 insertions, 15 deletions
diff --git a/staslib/udev.py b/staslib/udev.py index 12ef61b..80555dd 100644 --- a/staslib/udev.py +++ b/staslib/udev.py @@ -153,6 +153,169 @@ class Udev: return False + @staticmethod + def _cid_matches_tcp_tid_legacy(tid, cid): # pylint: disable=too-many-return-statements,too-many-branches + '''On kernels older than 6.1, the src_addr parameter is not available + from the sysfs. Therefore, we need to infer a match based on other + parameters. And there are a few cases where we're simply not sure + whether an existing connection (cid) matches the candidate + connection (tid). + ''' + cid_host_iface = cid['host-iface'] + cid_host_traddr = iputil.get_ipaddress_obj(cid['host-traddr'], ipv4_mapped_convert=True) + + if not cid_host_iface: # cid.host_iface is undefined + if not cid_host_traddr: # cid.host_traddr is undefined + # When the existing cid.src_addr, cid.host_traddr, and cid.host_iface + # are all undefined (which can only happen on kernels prior to 6.1), + # we can't know for sure on which interface an existing connection + # was made. In this case, we can only declare a match if both + # tid.host_iface and tid.host_traddr are undefined as well. + logging.debug( + 'Udev._cid_matches_tcp_tid_legacy() - cid=%s, tid=%s - Not enough info. Assume "match" but this could be wrong.', + cid, + tid, + ) + return True + + # cid.host_traddr is defined. If tid.host_traddr is also + # defined, then it must match the existing cid.host_traddr. + if tid.host_traddr: + tid_host_traddr = iputil.get_ipaddress_obj(tid.host_traddr, ipv4_mapped_convert=True) + if tid_host_traddr != cid_host_traddr: + return False + + # If tid.host_iface is defined, then the interface where + # the connection is located must match. If tid.host_iface + # is not defined, then we don't really care on which + # interface the connection was made and we can skip this test. + if tid.host_iface: + # With the existing cid.host_traddr, we can find the + # interface of the exisiting connection. + connection_iface = iputil.get_interface(str(cid_host_traddr)) + if tid.host_iface != connection_iface: + return False + + return True + + # cid.host_iface is defined + if not cid_host_traddr: # cid.host_traddr is undefined + if tid.host_iface and tid.host_iface != cid_host_iface: + return False + + if tid.host_traddr: + # It's impossible to tell the existing connection source + # address. So, we can't tell if it matches tid.host_traddr. + # However, if the existing host_iface has only one source + # address assigned to it, we can assume that the source + # address used for the existing connection is that address. + if_addrs = iputil.net_if_addrs().get(cid_host_iface, {4: [], 6: []}) + tid_host_traddr = iputil.get_ipaddress_obj(tid.host_traddr, ipv4_mapped_convert=True) + source_addrs = if_addrs[tid_host_traddr.version] + if len(source_addrs) != 1: + return False + + src_addr0 = iputil.get_ipaddress_obj(source_addrs[0], ipv4_mapped_convert=True) + if src_addr0 != tid_host_traddr: + return False + + return True + + # cid.host_traddr is defined + if tid.host_iface and tid.host_iface != cid_host_iface: + return False + + if tid.host_traddr: + tid_host_traddr = iputil.get_ipaddress_obj(tid.host_traddr, ipv4_mapped_convert=True) + if tid_host_traddr != cid_host_traddr: + return False + + return True + + @staticmethod + def _cid_matches_tid(tid, cid): # pylint: disable=too-many-return-statements,too-many-branches + '''Check if existing controller's cid matches candidate controller's tid. + @param cid: The Connection ID of an existing controller (from the sysfs). + @param tid: The Transport ID of a candidate controller. + + We're trying to find if an existing connection (specified by cid) can + be re-used for the candidate controller (specified by tid). + + We do not have a match if the candidate's tid.transport, tid.traddr, + tid.trsvcid, and tid.subsysnqn are not identical to those of the cid. + These 4 parameters are mandatory for a match. + + The tid.host_traddr and tid.host_iface depend on the transport type. + These parameters may not apply or have a different syntax/meaning + depending on the transport type. + + For TCP only: + With regards to the candidate's tid.host_traddr and tid.host_iface, + if those are defined but do not match the existing cid.host_traddr + and cid.host_iface, we may still be able to find a match by taking + the existing cid.src_addr into consideration since that parameter + identifies the actual source address of the connection and therefore + can be used to infer the interface of the connection. However, the + cid.src_addr can only be read from the sysfs starting with kernel + 6.1. + ''' + # 'transport', 'traddr', 'trsvcid', and 'subsysnqn' must exactly match. + if cid['transport'] != tid.transport or cid['trsvcid'] != tid.trsvcid or cid['subsysnqn'] != tid.subsysnqn: + return False + + if tid.transport in ('tcp', 'rdma'): + # Need to convert to ipaddress objects to properly + # handle all variations of IPv6 addresses. + tid_traddr = iputil.get_ipaddress_obj(tid.traddr, ipv4_mapped_convert=True) + cid_traddr = iputil.get_ipaddress_obj(cid['traddr'], ipv4_mapped_convert=True) + else: + cid_traddr = cid['traddr'] + tid_traddr = tid.traddr + + if cid_traddr != tid_traddr: + return False + + # We need to know the type of transport to compare 'host-traddr' and + # 'host-iface'. These parameters don't apply to all transport types + # and may have a different meaning/syntax. + if tid.transport == 'tcp': + if tid.host_traddr or tid.host_iface: + src_addr = iputil.get_ipaddress_obj(cid['src-addr'], ipv4_mapped_convert=True) + if not src_addr: + # For legacy kernels (i.e. older than 6.1), the existing cid.src_addr + # is always undefined. We need to use advanced logic to determine + # whether cid and tid match. + return Udev._cid_matches_tcp_tid_legacy(tid, cid) + + # The existing controller's cid.src_addr is always defined for kernel + # 6.1 and later. We can use the existing controller's cid.src_addr to + # find the interface on which the connection was made and therefore + # match it to the candidate's tid.host_iface. And the cid.src_addr + # can also be used to match the candidate's tid.host_traddr. + if tid.host_traddr: + tid_host_traddr = iputil.get_ipaddress_obj(tid.host_traddr, ipv4_mapped_convert=True) + if tid_host_traddr != src_addr: + return False + + # host-iface is an optional tcp-only parameter. + if tid.host_iface and tid.host_iface != iputil.get_interface(str(src_addr)): + return False + + elif tid.transport == 'fc': + # host-traddr is mandatory for FC. + if tid.host_traddr != cid['host-traddr']: + return False + + elif tid.transport == 'rdma': + # host-traddr is optional for RDMA and is expressed as an IP address. + if tid.host_traddr: + tid_host_traddr = iputil.get_ipaddress_obj(tid.host_traddr, ipv4_mapped_convert=True) + cid_host_traddr = iputil.get_ipaddress_obj(cid['host-traddr'], ipv4_mapped_convert=True) + if tid_host_traddr != cid_host_traddr: + return False + + return True + def find_nvme_dc_device(self, tid): '''@brief Find the nvme device associated with the specified Discovery Controller. @@ -164,7 +327,8 @@ class Udev: if not self.is_dc_device(device): continue - if self.get_tid(device) != tid: + cid = self.get_cid(device) + if not self._cid_matches_tid(tid, cid): continue return device @@ -182,7 +346,8 @@ class Udev: if not self.is_ioc_device(device): continue - if self.get_tid(device) != tid: + cid = self.get_cid(device) + if not self._cid_matches_tid(tid, cid): continue return device @@ -300,28 +465,32 @@ class Udev: return attr_str[start:end] @staticmethod - def _get_host_iface(device): - host_iface = Udev._get_property(device, 'NVME_HOST_IFACE') - if not host_iface: - # We'll try to find the interface from the source address on - # the connection. Only available if kernel exposes the source - # address (src_addr) in the "address" attribute. - src_addr = Udev.get_key_from_attr(device, 'address', 'src_addr=') - host_iface = iputil.get_interface(src_addr) - return host_iface - - @staticmethod def get_tid(device): '''@brief return the Transport ID associated with a udev device''' + cid = Udev.get_cid(device) + if cid['transport'] == 'tcp': + src_addr = cid['src-addr'] + if not cid['host-iface'] and src_addr: + # We'll try to find the interface from the source address on + # the connection. Only available if kernel exposes the source + # address (src_addr) in the "address" attribute. + cid['host-iface'] = iputil.get_interface(src_addr) + + return trid.TID(cid) + + @staticmethod + def get_cid(device): + '''@brief return the Connection ID associated with a udev device''' cid = { 'transport': Udev._get_property(device, 'NVME_TRTYPE'), 'traddr': Udev._get_property(device, 'NVME_TRADDR'), 'trsvcid': Udev._get_property(device, 'NVME_TRSVCID'), 'host-traddr': Udev._get_property(device, 'NVME_HOST_TRADDR'), - 'host-iface': Udev._get_host_iface(device), + 'host-iface': Udev._get_property(device, 'NVME_HOST_IFACE'), 'subsysnqn': Udev._get_attribute(device, 'subsysnqn'), + 'src-addr': Udev.get_key_from_attr(device, 'address', 'src_addr='), } - return trid.TID(cid) + return cid UDEV = Udev() # Singleton |