lib/netnsid.h

   1 /*
   2  * Copyright (c) 2017 Red Hat Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #ifndef NETNSID_H
  18 #define NETNSID_H 1
  19
  20 #include <stdbool.h>
  21
  22 #ifdef HAVE_LINUX_NET_NAMESPACE_H
  23 #include <linux/net_namespace.h>
  24 #endif
  25
  26 /*
  27  * The network namespace ID is a positive number that identifies the namespace
  28  * which the netlink message was sent.  It is used to identify if a received
  29  * message belongs to a port attached to the bridge.
  30  *
  31  * There are three port states listed below:
  32  * UNSET: A port in this state means that it could be either in same network
  33  * namespace as the daemon (LOCAL) or in another namespace (ID).  Any operation
  34  * on a port in this state that requires the ID will trigger a query to the
  35  * kernel to find out in which namespace the port currently is.
  36  *
  37  * LOCAL: A port in this state means that it is in the same network namespace
  38  * as the daemons.
  39  *
  40  * ID: A port that is not LOCAL and not UNSET has a valid positive (zero
  41  * included) remote namespace ID.
  42  *
  43  * Possible state changes:
  44  *
  45  * Initial port's state: UNSET.
  46  *
  47  * UNSET -> LOCAL: The daemon queries the kernel and finds that it's in the
  48  * same network namespace as the daemon or the API is not available (older
  49  * kernels).
  50  *
  51  * LOCAL -> UNSET: The kernel sends a deregistering netlink message which
  52  * unsets the port. It happens when the port is removed (or moved to another
  53  * network namespace).
  54  *
  55  * UNSET -> ID: The daemon queries the kernel and finds that the port is
  56  * in a specific network namespace with ID assigned.
  57  *
  58  * ID -> UNSET: When it receives a deregistering netlink message from that
  59  * namespace indicating the device is being removed (or moved to another
  60  * network namespace).
  61  */
  62
  63 #ifdef NETNSA_NSID_NOT_ASSIGNED
  64 #define NETNSID_LOCAL NETNSA_NSID_NOT_ASSIGNED
  65 #else
  66 #define NETNSID_LOCAL -1
  67 #endif
  68 #define NETNSID_UNSET (NETNSID_LOCAL - 1)
  69
  70 /* Prototypes */
  71 static inline void netnsid_set_local(int *nsid);
  72 static inline bool netnsid_is_local(int nsid);
  73 static inline void netnsid_unset(int *nsid);
  74 static inline bool netnsid_is_unset(int nsid);
  75 static inline bool netnsid_is_remote(int nsid);
  76 static inline void netnsid_set(int *nsid, int id);
  77 static inline bool netnsid_eq(int nsid1, int nsid2);
  78
  79 /* Functions */
  80 static inline void
  81 netnsid_set_local(int *nsid)
  82 {
  83     *nsid = NETNSID_LOCAL;
  84 }
  85
  86 static inline bool
  87 netnsid_is_local(int nsid)
  88 {
  89     return nsid == NETNSID_LOCAL;
  90 }
  91
  92 static inline void
  93 netnsid_unset(int *nsid)
  94 {
  95     *nsid = NETNSID_UNSET;
  96 }
  97
  98 static inline bool
  99 netnsid_is_unset(int nsid)
 100 {
 101     return nsid == NETNSID_UNSET;
 102 }
 103
 104 static inline bool
 105 netnsid_is_remote(int nsid)
 106 {
 107     if (netnsid_is_unset(nsid) || netnsid_is_local(nsid)) {
 108         return false;
 109     }
 110
 111     return true;
 112 }
 113
 114 static inline void
 115 netnsid_set(int *nsid, int id)
 116 {
 117     /* The kernel only sends positive numbers for valid IDs. */
 118     if (id != NETNSID_LOCAL) {
 119         ovs_assert(id >= 0);
 120     }
 121
 122     *nsid = id;
 123 }
 124
 125 static inline bool
 126 netnsid_eq(int nsid1, int nsid2)
 127 {
 128     if (netnsid_is_unset(nsid1) || netnsid_is_unset(nsid2)) {
 129         return false;
 130     }
 131
 132     if (nsid1 == nsid2) {
 133         return true;
 134     }
 135
 136     return false;
 137 }
 138
 139 #endif