lib/tc.c

   1 /*
   2  * Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 Nicira, 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 #include <config.h>
  18 #include "tc.h"
  19 #include <errno.h>
  20 #include "netlink-socket.h"
  21 #include "netlink.h"
  22 #include "openvswitch/ofpbuf.h"
  23 #include "openvswitch/vlog.h"
  24
  25 VLOG_DEFINE_THIS_MODULE(tc);
  26
  27 /* Returns tc handle 'major':'minor'. */
  28 unsigned int
  29 tc_make_handle(unsigned int major, unsigned int minor)
  30 {
  31     return TC_H_MAKE(major << 16, minor);
  32 }
  33
  34 /* Returns the major number from 'handle'. */
  35 unsigned int
  36 tc_get_major(unsigned int handle)
  37 {
  38     return TC_H_MAJ(handle) >> 16;
  39 }
  40
  41 /* Returns the minor number from 'handle'. */
  42 unsigned int
  43 tc_get_minor(unsigned int handle)
  44 {
  45     return TC_H_MIN(handle);
  46 }
  47
  48 struct tcmsg *
  49 tc_make_request(int ifindex, int type, unsigned int flags,
  50                 struct ofpbuf *request)
  51 {
  52     struct tcmsg *tcmsg;
  53
  54     ofpbuf_init(request, 512);
  55     nl_msg_put_nlmsghdr(request, sizeof *tcmsg, type, NLM_F_REQUEST | flags);
  56     tcmsg = ofpbuf_put_zeros(request, sizeof *tcmsg);
  57     tcmsg->tcm_family = AF_UNSPEC;
  58     tcmsg->tcm_ifindex = ifindex;
  59     /* Caller should fill in tcmsg->tcm_handle. */
  60     /* Caller should fill in tcmsg->tcm_parent. */
  61
  62     return tcmsg;
  63 }
  64
  65 int
  66 tc_transact(struct ofpbuf *request, struct ofpbuf **replyp)
  67 {
  68     int error = nl_transact(NETLINK_ROUTE, request, replyp);
  69     ofpbuf_uninit(request);
  70     return error;
  71 }
  72
  73 /* Adds or deletes a root ingress qdisc on device with specified ifindex.
  74  *
  75  * This function is equivalent to running the following when 'add' is true:
  76  *     /sbin/tc qdisc add dev <devname> handle ffff: ingress
  77  *
  78  * This function is equivalent to running the following when 'add' is false:
  79  *     /sbin/tc qdisc del dev <devname> handle ffff: ingress
  80  *
  81  * Where dev <devname> is the device with specified ifindex name.
  82  *
  83  * The configuration and stats may be seen with the following command:
  84  *     /sbin/tc -s qdisc show dev <devname>
  85  *
  86  * Returns 0 if successful, otherwise a positive errno value.
  87  */
  88 int
  89 tc_add_del_ingress_qdisc(int ifindex, bool add)
  90 {
  91     struct ofpbuf request;
  92     struct tcmsg *tcmsg;
  93     int error;
  94     int type = add ? RTM_NEWQDISC : RTM_DELQDISC;
  95     int flags = add ? NLM_F_EXCL | NLM_F_CREATE : 0;
  96
  97     tcmsg = tc_make_request(ifindex, type, flags, &request);
  98     tcmsg->tcm_handle = tc_make_handle(0xffff, 0);
  99     tcmsg->tcm_parent = TC_H_INGRESS;
 100     nl_msg_put_string(&request, TCA_KIND, "ingress");
 101     nl_msg_put_unspec(&request, TCA_OPTIONS, NULL, 0);
 102
 103     error = tc_transact(&request, NULL);
 104     if (error) {
 105         /* If we're deleting the qdisc, don't worry about some of the
 106          * error conditions. */
 107         if (!add && (error == ENOENT || error == EINVAL)) {
 108             return 0;
 109         }
 110         return error;
 111     }
 112
 113     return 0;
 114 }