lib/ovs-router.c

   1 /*
   2  * Copyright (c) 2014, 2015 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 <arpa/inet.h>
  19 #include <errno.h>
  20 #include <inttypes.h>
  21 #include <sys/socket.h>
  22 #include <net/if.h>
  23 #include <netinet/in.h>
  24 #include <stdarg.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <unistd.h>
  28
  29 #include "classifier.h"
  30 #include "command-line.h"
  31 #include "compiler.h"
  32 #include "dpif.h"
  33 #include "dynamic-string.h"
  34 #include "netdev.h"
  35 #include "packets.h"
  36 #include "seq.h"
  37 #include "ovs-router.h"
  38 #include "ovs-thread.h"
  39 #include "route-table.h"
  40 #include "unixctl.h"
  41 #include "util.h"
  42
  43 static struct ovs_mutex mutex = OVS_MUTEX_INITIALIZER;
  44 static struct classifier cls;
  45
  46 struct ovs_router_entry {
  47     struct cls_rule cr;
  48     char output_bridge[IFNAMSIZ];
  49     ovs_be32 gw;
  50     ovs_be32 nw_addr;
  51     uint8_t plen;
  52     uint8_t priority;
  53 };
  54
  55 static struct ovs_router_entry *
  56 ovs_router_entry_cast(const struct cls_rule *cr)
  57 {
  58     if (offsetof(struct ovs_router_entry, cr) == 0) {
  59         return CONTAINER_OF(cr, struct ovs_router_entry, cr);
  60     } else {
  61         return cr ? CONTAINER_OF(cr, struct ovs_router_entry, cr) : NULL;
  62     }
  63 }
  64
  65 bool
  66 ovs_router_lookup(ovs_be32 ip_dst, char output_bridge[], ovs_be32 *gw)
  67 {
  68     const struct cls_rule *cr;
  69     struct flow flow = {.nw_dst = ip_dst};
  70
  71     cr = classifier_lookup(&cls, &flow, NULL);
  72     if (cr) {
  73         struct ovs_router_entry *p = ovs_router_entry_cast(cr);
  74
  75         strncpy(output_bridge, p->output_bridge, IFNAMSIZ);
  76         *gw = p->gw;
  77         return true;
  78     }
  79     return route_table_fallback_lookup(ip_dst, output_bridge, gw);
  80 }
  81
  82 static void
  83 rt_entry_free(struct ovs_router_entry *p)
  84 {
  85     cls_rule_destroy(&p->cr);
  86     free(p);
  87 }
  88
  89 static void rt_init_match(struct match *match, ovs_be32 ip_dst, uint8_t plen)
  90 {
  91     ovs_be32 mask;
  92
  93     mask = be32_prefix_mask(plen);
  94
  95     ip_dst &= mask; /* Clear out insignificant bits. */
  96     memset(match, 0, sizeof *match);
  97     match->flow.nw_dst = ip_dst;
  98     match->wc.masks.nw_dst = mask;
  99 }
 100
 101 static void
 102 ovs_router_insert__(uint8_t priority, ovs_be32 ip_dst, uint8_t plen,
 103                     const char output_bridge[],
 104                     ovs_be32 gw)
 105 {
 106     const struct cls_rule *cr;
 107     struct ovs_router_entry *p;
 108     struct match match;
 109
 110     rt_init_match(&match, ip_dst, plen);
 111
 112     p = xzalloc(sizeof *p);
 113     strncpy(p->output_bridge, output_bridge, IFNAMSIZ);
 114     p->gw = gw;
 115     p->nw_addr = match.flow.nw_dst;
 116     p->plen = plen;
 117     p->priority = priority;
 118     cls_rule_init(&p->cr, &match, priority); /* Longest prefix matches first. */
 119
 120     ovs_mutex_lock(&mutex);
 121     cr = classifier_replace(&cls, &p->cr, NULL, 0);
 122     ovs_mutex_unlock(&mutex);
 123
 124     if (cr) {
 125         /* An old rule with the same match was displaced. */
 126         ovsrcu_postpone(rt_entry_free, ovs_router_entry_cast(cr));
 127     }
 128     seq_change(tnl_conf_seq);
 129 }
 130
 131 void
 132 ovs_router_insert(ovs_be32 ip_dst, uint8_t plen, const char output_bridge[],
 133                   ovs_be32 gw)
 134 {
 135     ovs_router_insert__(plen, ip_dst, plen, output_bridge, gw);
 136 }
 137
 138 static bool
 139 rt_entry_delete(uint8_t priority, ovs_be32 ip_dst, uint8_t plen)
 140 {
 141     const struct cls_rule *cr;
 142     struct cls_rule rule;
 143     struct match match;
 144
 145     rt_init_match(&match, ip_dst, plen);
 146
 147     cls_rule_init(&rule, &match, priority);
 148
 149     /* Find the exact rule. */
 150     cr = classifier_find_rule_exactly(&cls, &rule);
 151     if (cr) {
 152         /* Remove it. */
 153         ovs_mutex_lock(&mutex);
 154         cr = classifier_remove(&cls, cr);
 155         ovs_mutex_unlock(&mutex);
 156
 157         if (cr) {
 158             ovsrcu_postpone(rt_entry_free, ovs_router_entry_cast(cr));
 159             return true;
 160         }
 161     }
 162     return false;
 163 }
 164
 165 static bool
 166 scan_ipv4_route(const char *s, ovs_be32 *addr, unsigned int *plen)
 167 {
 168     int len, max_plen, n;
 169     int slen = strlen(s);
 170     uint8_t *ip = (uint8_t *)addr;
 171
 172     *addr = htonl(0);
 173     if (!ovs_scan(s, "%"SCNu8"%n", &ip[0], &n)) {
 174         return false;
 175     }
 176     len = n;
 177     max_plen = 8;
 178     for (int i = 1; i < 4; i++) {
 179         if (ovs_scan(s + len, ".%"SCNu8"%n", &ip[i], &n)) {
 180             len += n;
 181             max_plen += 8;
 182         } else {
 183             break;
 184         }
 185     }
 186     if (len == slen && max_plen == 32) {
 187         *plen = 32;
 188         return true;
 189     }
 190     if (ovs_scan(s + len, "/%u%n", plen, &n)
 191         && len + n == slen && *plen <= max_plen) {
 192         return true;
 193     }
 194     return false;
 195 }
 196
 197 static void
 198 ovs_router_add(struct unixctl_conn *conn, int argc,
 199               const char *argv[], void *aux OVS_UNUSED)
 200 {
 201     ovs_be32 ip, gw;
 202     unsigned int plen;
 203
 204     if (scan_ipv4_route(argv[1], &ip, &plen)) {
 205         if (argc > 3) {
 206             inet_pton(AF_INET, argv[3], (struct in_addr *)&gw);
 207         } else {
 208             gw = 0;
 209         }
 210         ovs_router_insert__(plen + 32, ip, plen, argv[2], gw);
 211         unixctl_command_reply(conn, "OK");
 212     } else {
 213         unixctl_command_reply(conn, "Invalid parameters");
 214     }
 215 }
 216
 217 static void
 218 ovs_router_del(struct unixctl_conn *conn, int argc OVS_UNUSED,
 219               const char *argv[], void *aux OVS_UNUSED)
 220 {
 221     ovs_be32 ip;
 222     unsigned int plen;
 223
 224     if (scan_ipv4_route(argv[1], &ip, &plen)) {
 225
 226         if (rt_entry_delete(plen + 32, ip, plen)) {
 227             unixctl_command_reply(conn, "OK");
 228             seq_change(tnl_conf_seq);
 229         } else {
 230             unixctl_command_reply(conn, "Not found");
 231         }
 232     } else {
 233         unixctl_command_reply(conn, "Invalid parameters");
 234     }
 235 }
 236
 237 static void
 238 ovs_router_show(struct unixctl_conn *conn, int argc OVS_UNUSED,
 239                const char *argv[] OVS_UNUSED, void *aux OVS_UNUSED)
 240 {
 241     struct ovs_router_entry *rt;
 242     struct ds ds = DS_EMPTY_INITIALIZER;
 243
 244     ds_put_format(&ds, "Route Table:\n");
 245     CLS_FOR_EACH(rt, cr, &cls) {
 246         if (rt->priority == rt->plen) {
 247             ds_put_format(&ds, "Cached: ");
 248         } else {
 249             ds_put_format(&ds, "User: ");
 250         }
 251         ds_put_format(&ds, IP_FMT"/%"PRIu16" dev %s",
 252                       IP_ARGS(rt->nw_addr), rt->plen,
 253                       rt->output_bridge);
 254         if (rt->gw) {
 255             ds_put_format(&ds, " GW "IP_FMT, IP_ARGS(rt->gw));
 256         }
 257         ds_put_format(&ds, "\n");
 258     }
 259     unixctl_command_reply(conn, ds_cstr(&ds));
 260     ds_destroy(&ds);
 261 }
 262
 263 static void
 264 ovs_router_lookup_cmd(struct unixctl_conn *conn, int argc OVS_UNUSED,
 265                       const char *argv[], void *aux OVS_UNUSED)
 266 {
 267     ovs_be32 ip;
 268     unsigned int plen;
 269
 270     if (scan_ipv4_route(argv[1], &ip, &plen) && plen == 32) {
 271         char iface[IFNAMSIZ];
 272         ovs_be32 gw;
 273
 274         if (ovs_router_lookup(ip, iface, &gw)) {
 275             struct ds ds = DS_EMPTY_INITIALIZER;
 276
 277             ds_put_format(&ds, "gateway " IP_FMT "\n", IP_ARGS(gw));
 278             ds_put_format(&ds, "dev %s\n", iface);
 279             unixctl_command_reply(conn, ds_cstr(&ds));
 280         } else {
 281             unixctl_command_reply(conn, "Not found");
 282         }
 283     } else {
 284         unixctl_command_reply(conn, "Invalid parameters");
 285     }
 286 }
 287
 288 void
 289 ovs_router_flush(void)
 290 {
 291     struct ovs_router_entry *rt;
 292
 293     ovs_mutex_lock(&mutex);
 294     classifier_defer(&cls);
 295     CLS_FOR_EACH(rt, cr, &cls) {
 296         if (rt->priority == rt->plen) {
 297             if (classifier_remove(&cls, &rt->cr)) {
 298                 ovsrcu_postpone(rt_entry_free, rt);
 299             }
 300         }
 301     }
 302     classifier_publish(&cls);
 303     ovs_mutex_unlock(&mutex);
 304     seq_change(tnl_conf_seq);
 305 }
 306
 307 /* May not be called more than once. */
 308 void
 309 ovs_router_init(void)
 310 {
 311     classifier_init(&cls, NULL);
 312     unixctl_command_register("ovs/route/add", "ipv4_addr/prefix_len out_br_name gw", 2, 3,
 313                              ovs_router_add, NULL);
 314     unixctl_command_register("ovs/route/show", "", 0, 0, ovs_router_show, NULL);
 315     unixctl_command_register("ovs/route/del", "ipv4_addr/prefix_len", 1, 1, ovs_router_del,
 316                              NULL);
 317     unixctl_command_register("ovs/route/lookup", "ipv4_addr", 1, 1,
 318                              ovs_router_lookup_cmd, NULL);
 319 }