1/*
2  PIM for Quagga
3  Copyright (C) 2008  Everton da Silva Marques
4
5  This program is free software; you can redistribute it and/or modify
6  it under the terms of the GNU General Public License as published by
7  the Free Software Foundation; either version 2 of the License, or
8  (at your option) any later version.
9
10  This program is distributed in the hope that it will be useful, but
11  WITHOUT ANY WARRANTY; without even the implied warranty of
12  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  General Public License for more details.
14
15  You should have received a copy of the GNU General Public License
16  along with this program; see the file COPYING; if not, write to the
17  Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
18  MA 02110-1301 USA
19
20  $QuaggaId: $Format:%an, %ai, %h$ $
21*/
22
23#include <zebra.h>
24
25#include "log.h"
26#include "prefix.h"
27#include "memory.h"
28
29#include "pimd.h"
30#include "pim_rpf.h"
31#include "pim_pim.h"
32#include "pim_str.h"
33#include "pim_iface.h"
34#include "pim_zlookup.h"
35#include "pim_ifchannel.h"
36
37static struct in_addr pim_rpf_find_rpf_addr(struct pim_upstream *up);
38
39int pim_nexthop_lookup(struct pim_nexthop *nexthop,
40		       struct in_addr addr)
41{
42  struct pim_zlookup_nexthop nexthop_tab[PIM_NEXTHOP_IFINDEX_TAB_SIZE];
43  int num_ifindex;
44  struct interface *ifp;
45  int first_ifindex;
46
47  num_ifindex = zclient_lookup_nexthop(qpim_zclient_lookup, nexthop_tab,
48				       PIM_NEXTHOP_IFINDEX_TAB_SIZE,
49				       addr, PIM_NEXTHOP_LOOKUP_MAX);
50  if (num_ifindex < 1) {
51    char addr_str[100];
52    pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
53    zlog_warn("%s %s: could not find nexthop ifindex for address %s",
54	      __FILE__, __PRETTY_FUNCTION__,
55	      addr_str);
56    return -1;
57  }
58
59  first_ifindex = nexthop_tab[0].ifindex;
60
61  if (num_ifindex > 1) {
62    char addr_str[100];
63    pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
64    zlog_debug("%s %s: FIXME ignoring multiple nexthop ifindex'es num_ifindex=%d for address %s (using only ifindex=%d)",
65	      __FILE__, __PRETTY_FUNCTION__,
66	      num_ifindex, addr_str, first_ifindex);
67    /* debug warning only, do not return */
68  }
69
70  ifp = if_lookup_by_index(first_ifindex);
71  if (!ifp) {
72    char addr_str[100];
73    pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
74    zlog_warn("%s %s: could not find interface for ifindex %d (address %s)",
75	      __FILE__, __PRETTY_FUNCTION__,
76	      first_ifindex, addr_str);
77    return -2;
78  }
79
80  if (!ifp->info) {
81    char addr_str[100];
82    pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
83    zlog_warn("%s: multicast not enabled on input interface %s (ifindex=%d, RPF for source %s)",
84	      __PRETTY_FUNCTION__,
85	      ifp->name, first_ifindex, addr_str);
86    /* debug warning only, do not return */
87  }
88
89  if (PIM_DEBUG_PIM_TRACE) {
90    char nexthop_str[100];
91    char addr_str[100];
92    pim_inet4_dump("<nexthop?>", nexthop_tab[0].nexthop_addr, nexthop_str, sizeof(nexthop_str));
93    pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
94    zlog_debug("%s %s: found nexthop %s for address %s: interface %s ifindex=%d metric=%d pref=%d",
95	       __FILE__, __PRETTY_FUNCTION__,
96	       nexthop_str, addr_str,
97	       ifp->name, first_ifindex,
98	       nexthop_tab[0].route_metric,
99	       nexthop_tab[0].protocol_distance);
100  }
101
102  /* update nextop data */
103  nexthop->interface              = ifp;
104  nexthop->mrib_nexthop_addr      = nexthop_tab[0].nexthop_addr;
105  nexthop->mrib_metric_preference = nexthop_tab[0].protocol_distance;
106  nexthop->mrib_route_metric      = nexthop_tab[0].route_metric;
107
108  return 0;
109}
110
111static int nexthop_mismatch(const struct pim_nexthop *nh1,
112			    const struct pim_nexthop *nh2)
113{
114  return (nh1->interface != nh2->interface)
115    ||
116    (nh1->mrib_nexthop_addr.s_addr != nh2->mrib_nexthop_addr.s_addr)
117    ||
118    (nh1->mrib_metric_preference != nh2->mrib_metric_preference)
119    ||
120    (nh1->mrib_route_metric != nh2->mrib_route_metric);
121}
122
123enum pim_rpf_result pim_rpf_update(struct pim_upstream *up,
124				   struct in_addr *old_rpf_addr)
125{
126  struct in_addr      save_rpf_addr;
127  struct pim_nexthop  save_nexthop;
128  struct pim_rpf     *rpf = &up->rpf;
129
130  save_nexthop  = rpf->source_nexthop; /* detect change in pim_nexthop */
131  save_rpf_addr = rpf->rpf_addr;       /* detect change in RPF'(S,G) */
132
133  if (pim_nexthop_lookup(&rpf->source_nexthop,
134			 up->source_addr)) {
135    return PIM_RPF_FAILURE;
136  }
137
138  rpf->rpf_addr = pim_rpf_find_rpf_addr(up);
139  if (PIM_INADDR_IS_ANY(rpf->rpf_addr)) {
140    /* RPF'(S,G) not found */
141    char src_str[100];
142    char grp_str[100];
143    pim_inet4_dump("<src?>", up->source_addr, src_str, sizeof(src_str));
144    pim_inet4_dump("<grp?>", up->group_addr, grp_str, sizeof(grp_str));
145    zlog_warn("%s %s: RPF'(%s,%s) not found: won't send join upstream",
146              __FILE__, __PRETTY_FUNCTION__,
147              src_str, grp_str);
148    /* warning only */
149  }
150
151  /* detect change in pim_nexthop */
152  if (nexthop_mismatch(&rpf->source_nexthop, &save_nexthop)) {
153
154    /* if (PIM_DEBUG_PIM_EVENTS) */ {
155      char src_str[100];
156      char grp_str[100];
157      char nhaddr_str[100];
158      pim_inet4_dump("<src?>", up->source_addr, src_str, sizeof(src_str));
159      pim_inet4_dump("<grp?>", up->group_addr, grp_str, sizeof(grp_str));
160      pim_inet4_dump("<addr?>", rpf->source_nexthop.mrib_nexthop_addr, nhaddr_str, sizeof(nhaddr_str));
161      zlog_debug("%s %s: (S,G)=(%s,%s) source nexthop now is: interface=%s address=%s pref=%d metric=%d",
162		 __FILE__, __PRETTY_FUNCTION__,
163		 src_str, grp_str,
164		 rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<ifname?>",
165		 nhaddr_str,
166		 rpf->source_nexthop.mrib_metric_preference,
167		 rpf->source_nexthop.mrib_route_metric);
168      /* warning only */
169    }
170
171    pim_upstream_update_join_desired(up);
172    pim_upstream_update_could_assert(up);
173    pim_upstream_update_my_assert_metric(up);
174  }
175
176  /* detect change in RPF_interface(S) */
177  if (save_nexthop.interface != rpf->source_nexthop.interface) {
178
179    /* if (PIM_DEBUG_PIM_EVENTS) */ {
180      char src_str[100];
181      char grp_str[100];
182      pim_inet4_dump("<src?>", up->source_addr, src_str, sizeof(src_str));
183      pim_inet4_dump("<grp?>", up->group_addr, grp_str, sizeof(grp_str));
184      zlog_debug("%s %s: (S,G)=(%s,%s) RPF_interface(S) changed from %s to %s",
185		 __FILE__, __PRETTY_FUNCTION__,
186		 src_str, grp_str,
187		 save_nexthop.interface ? save_nexthop.interface->name : "<oldif?>",
188		 rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<newif?>");
189      /* warning only */
190    }
191
192    pim_upstream_rpf_interface_changed(up, save_nexthop.interface);
193  }
194
195  /* detect change in RPF'(S,G) */
196  if (save_rpf_addr.s_addr != rpf->rpf_addr.s_addr) {
197
198    /* return old rpf to caller ? */
199    if (old_rpf_addr)
200      *old_rpf_addr = save_rpf_addr;
201
202    return PIM_RPF_CHANGED;
203  }
204
205  return PIM_RPF_OK;
206}
207
208/*
209  RFC 4601: 4.1.6.  State Summarization Macros
210
211     neighbor RPF'(S,G) {
212         if ( I_Am_Assert_Loser(S, G, RPF_interface(S) )) {
213              return AssertWinner(S, G, RPF_interface(S) )
214         } else {
215              return NBR( RPF_interface(S), MRIB.next_hop( S ) )
216         }
217     }
218
219  RPF'(*,G) and RPF'(S,G) indicate the neighbor from which data
220  packets should be coming and to which joins should be sent on the RP
221  tree and SPT, respectively.
222*/
223static struct in_addr pim_rpf_find_rpf_addr(struct pim_upstream *up)
224{
225  struct pim_ifchannel *rpf_ch;
226  struct pim_neighbor *neigh;
227  struct in_addr rpf_addr;
228
229  if (!up->rpf.source_nexthop.interface) {
230    char src_str[100];
231    char grp_str[100];
232    pim_inet4_dump("<src?>", up->source_addr, src_str, sizeof(src_str));
233    pim_inet4_dump("<grp?>", up->group_addr, grp_str, sizeof(grp_str));
234    zlog_warn("%s: missing RPF interface for upstream (S,G)=(%s,%s)",
235	      __PRETTY_FUNCTION__,
236	      src_str, grp_str);
237
238    rpf_addr.s_addr = PIM_NET_INADDR_ANY;
239    return rpf_addr;
240  }
241
242  rpf_ch = pim_ifchannel_find(up->rpf.source_nexthop.interface,
243			      up->source_addr, up->group_addr);
244  if (rpf_ch) {
245    if (rpf_ch->ifassert_state == PIM_IFASSERT_I_AM_LOSER) {
246      return rpf_ch->ifassert_winner;
247    }
248  }
249
250  /* return NBR( RPF_interface(S), MRIB.next_hop( S ) ) */
251
252  neigh = pim_if_find_neighbor(up->rpf.source_nexthop.interface,
253			       up->rpf.source_nexthop.mrib_nexthop_addr);
254  if (neigh)
255    rpf_addr = neigh->source_addr;
256  else
257    rpf_addr.s_addr = PIM_NET_INADDR_ANY;
258
259  return rpf_addr;
260}
261