The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/netlink/route/rt.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 2021 Ng Peng Nam Sean
    5  * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   19  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   26  * SUCH DAMAGE.
   27  */
   28 
   29 #include <sys/cdefs.h>
   30 __FBSDID("$FreeBSD$");
   31 #include "opt_inet.h"
   32 #include "opt_inet6.h"
   33 #include "opt_route.h"
   34 #include <sys/types.h>
   35 #include <sys/malloc.h>
   36 #include <sys/rmlock.h>
   37 #include <sys/socket.h>
   38 
   39 #include <net/if.h>
   40 #include <net/route.h>
   41 #include <net/route/nhop.h>
   42 #include <net/route/route_ctl.h>
   43 #include <net/route/route_var.h>
   44 #include <netlink/netlink.h>
   45 #include <netlink/netlink_ctl.h>
   46 #include <netlink/netlink_route.h>
   47 #include <netlink/route/route_var.h>
   48 
   49 #define DEBUG_MOD_NAME  nl_route
   50 #define DEBUG_MAX_LEVEL LOG_DEBUG3
   51 #include <netlink/netlink_debug.h>
   52 _DECLARE_DEBUG(LOG_DEBUG);
   53 
   54 static unsigned char
   55 get_rtm_type(const struct nhop_object *nh)
   56 {
   57         int nh_flags = nh->nh_flags;
   58 
   59         /* Use the fact that nhg runtime flags are only NHF_MULTIPATH */
   60         if (nh_flags & NHF_BLACKHOLE)
   61                 return (RTN_BLACKHOLE);
   62         else if (nh_flags & NHF_REJECT)
   63                 return (RTN_PROHIBIT);
   64         return (RTN_UNICAST);
   65 }
   66 
   67 static uint8_t
   68 nl_get_rtm_protocol(const struct nhop_object *nh)
   69 {
   70 #ifdef ROUTE_MPATH
   71         if (NH_IS_NHGRP(nh)) {
   72                 const struct nhgrp_object *nhg = (const struct nhgrp_object *)nh;
   73                 uint8_t origin = nhgrp_get_origin(nhg);
   74                 if (origin != RTPROT_UNSPEC)
   75                         return (origin);
   76                 nh = nhg->nhops[0];
   77         }
   78 #endif
   79         uint8_t origin = nhop_get_origin(nh);
   80         if (origin != RTPROT_UNSPEC)
   81                 return (origin);
   82         /* TODO: remove guesswork once all kernel users fill in origin */
   83         int rt_flags = nhop_get_rtflags(nh);
   84         if (rt_flags & RTF_PROTO1)
   85                 return (RTPROT_ZEBRA);
   86         if (rt_flags & RTF_STATIC)
   87                 return (RTPROT_STATIC);
   88         return (RTPROT_KERNEL);
   89 }
   90 
   91 static int
   92 get_rtmsg_type_from_rtsock(int cmd)
   93 {
   94         switch (cmd) {
   95         case RTM_ADD:
   96         case RTM_CHANGE:
   97         case RTM_GET:
   98                 return NL_RTM_NEWROUTE;
   99         case RTM_DELETE:
  100                 return NL_RTM_DELROUTE;
  101         }
  102 
  103         return (0);
  104 }
  105 
  106 /*
  107  * fibnum heuristics
  108  *
  109  * if (dump && rtm_table == 0 && !rta_table) RT_ALL_FIBS
  110  * msg                rtm_table     RTA_TABLE            result
  111  * RTM_GETROUTE/dump          0             -       RT_ALL_FIBS
  112  * RTM_GETROUTE/dump          1             -                 1
  113  * RTM_GETROUTE/get           0             -                 0
  114  *
  115  */
  116 
  117 static struct nhop_object *
  118 rc_get_nhop(const struct rib_cmd_info *rc)
  119 {
  120         return ((rc->rc_cmd == RTM_DELETE) ? rc->rc_nh_old : rc->rc_nh_new);
  121 }
  122 
  123 static void
  124 dump_rc_nhop_gw(struct nl_writer *nw, const struct nhop_object *nh)
  125 {
  126         int upper_family;
  127 
  128         switch (nhop_get_neigh_family(nh)) {
  129         case AF_LINK:
  130                 /* onlink prefix, skip */
  131                 break;
  132         case AF_INET:
  133                 nlattr_add(nw, NL_RTA_GATEWAY, 4, &nh->gw4_sa.sin_addr);
  134                 break;
  135         case AF_INET6:
  136                 upper_family = nhop_get_upper_family(nh);
  137                 if (upper_family == AF_INET6) {
  138                         nlattr_add(nw, NL_RTA_GATEWAY, 16, &nh->gw6_sa.sin6_addr);
  139                 } else if (upper_family == AF_INET) {
  140                         /* IPv4 over IPv6 */
  141                         char buf[20];
  142                         struct rtvia *via = (struct rtvia *)&buf[0];
  143                         via->rtvia_family = AF_INET6;
  144                         memcpy(via->rtvia_addr, &nh->gw6_sa.sin6_addr, 16);
  145                         nlattr_add(nw, NL_RTA_VIA, 17, via);
  146                 }
  147                 break;
  148         }
  149 }
  150 
  151 static void
  152 dump_rc_nhop_mtu(struct nl_writer *nw, const struct nhop_object *nh)
  153 {
  154         int nla_len = sizeof(struct nlattr) * 2 + sizeof(uint32_t);
  155         struct nlattr *nla = nlmsg_reserve_data(nw, nla_len, struct nlattr);
  156 
  157         if (nla == NULL)
  158                 return;
  159         nla->nla_type = NL_RTA_METRICS;
  160         nla->nla_len = nla_len;
  161         nla++;
  162         nla->nla_type = NL_RTAX_MTU;
  163         nla->nla_len = sizeof(struct nlattr) + sizeof(uint32_t);
  164         *((uint32_t *)(nla + 1)) = nh->nh_mtu;
  165 }
  166 
  167 #ifdef ROUTE_MPATH
  168 static void
  169 dump_rc_nhg(struct nl_writer *nw, const struct nhgrp_object *nhg, struct rtmsg *rtm)
  170 {
  171         uint32_t uidx = nhgrp_get_uidx(nhg);
  172         uint32_t num_nhops;
  173         const struct weightened_nhop *wn = nhgrp_get_nhops(nhg, &num_nhops);
  174         uint32_t base_rtflags = nhop_get_rtflags(wn[0].nh);
  175 
  176         if (uidx != 0)
  177                 nlattr_add_u32(nw, NL_RTA_NH_ID, uidx);
  178         nlattr_add_u32(nw, NL_RTA_KNH_ID, nhgrp_get_idx(nhg));
  179 
  180         nlattr_add_u32(nw, NL_RTA_RTFLAGS, base_rtflags);
  181         int off = nlattr_add_nested(nw, NL_RTA_MULTIPATH);
  182         if (off == 0)
  183                 return;
  184 
  185         for (int i = 0; i < num_nhops; i++) {
  186                 int nh_off = nlattr_save_offset(nw);
  187                 struct rtnexthop *rtnh = nlmsg_reserve_object(nw, struct rtnexthop);
  188                 if (rtnh == NULL)
  189                         return;
  190                 rtnh->rtnh_flags = 0;
  191                 rtnh->rtnh_ifindex = wn[i].nh->nh_ifp->if_index;
  192                 rtnh->rtnh_hops = wn[i].weight;
  193                 dump_rc_nhop_gw(nw, wn[i].nh);
  194                 uint32_t rtflags = nhop_get_rtflags(wn[i].nh);
  195                 if (rtflags != base_rtflags)
  196                         nlattr_add_u32(nw, NL_RTA_RTFLAGS, rtflags);
  197                 if (rtflags & RTF_FIXEDMTU)
  198                         dump_rc_nhop_mtu(nw, wn[i].nh);
  199                 rtnh = nlattr_restore_offset(nw, nh_off, struct rtnexthop);
  200                 /*
  201                  * nlattr_add() allocates 4-byte aligned storage, no need to aligh
  202                  * length here
  203                  * */
  204                 rtnh->rtnh_len = nlattr_save_offset(nw) - nh_off;
  205         }
  206         nlattr_set_len(nw, off);
  207 }
  208 #endif
  209 
  210 static void
  211 dump_rc_nhop(struct nl_writer *nw, const struct nhop_object *nh, struct rtmsg *rtm)
  212 {
  213 #ifdef ROUTE_MPATH
  214         if (NH_IS_NHGRP(nh)) {
  215                 dump_rc_nhg(nw, (const struct nhgrp_object *)nh, rtm);
  216                 return;
  217         }
  218 #endif
  219         uint32_t rtflags = nhop_get_rtflags(nh);
  220 
  221         /*
  222          * IPv4 over IPv6
  223          *    ('RTA_VIA', {'family': 10, 'addr': 'fe80::20c:29ff:fe67:2dd'}), ('RTA_OIF', 2),
  224          * IPv4 w/ gw
  225          *    ('RTA_GATEWAY', '172.16.107.131'), ('RTA_OIF', 2)],
  226          * Direct route:
  227          *    ('RTA_OIF', 2)
  228          */
  229         if (nh->nh_flags & NHF_GATEWAY)
  230                 dump_rc_nhop_gw(nw, nh);
  231 
  232         uint32_t uidx = nhop_get_uidx(nh);
  233         if (uidx != 0)
  234                 nlattr_add_u32(nw, NL_RTA_NH_ID, uidx);
  235         nlattr_add_u32(nw, NL_RTA_KNH_ID, nhop_get_idx(nh));
  236         nlattr_add_u32(nw, NL_RTA_RTFLAGS, rtflags);
  237 
  238         if (rtflags & RTF_FIXEDMTU)
  239                 dump_rc_nhop_mtu(nw, nh);
  240         uint32_t nh_expire = nhop_get_expire(nh);
  241         if (nh_expire > 0)
  242                 nlattr_add_u32(nw, NL_RTA_EXPIRES, nh_expire - time_uptime);
  243 
  244         /* In any case, fill outgoing interface */
  245         nlattr_add_u32(nw, NL_RTA_OIF, nh->nh_ifp->if_index);
  246 }
  247 
  248 /*
  249  * Dumps output from a rib command into an rtmsg
  250  */
  251 
  252 static int
  253 dump_px(uint32_t fibnum, const struct nlmsghdr *hdr,
  254     const struct rtentry *rt, struct route_nhop_data *rnd,
  255     struct nl_writer *nw)
  256 {
  257         struct rtmsg *rtm;
  258         int error = 0;
  259 
  260         NET_EPOCH_ASSERT();
  261 
  262         if (!nlmsg_reply(nw, hdr, sizeof(struct rtmsg)))
  263                 goto enomem;
  264 
  265         int family = rt_get_family(rt);
  266         int rtm_off = nlattr_save_offset(nw);
  267         rtm = nlmsg_reserve_object(nw, struct rtmsg);
  268         rtm->rtm_family = family;
  269         rtm->rtm_dst_len = 0;
  270         rtm->rtm_src_len = 0;
  271         rtm->rtm_tos = 0;
  272         if (fibnum < 255)
  273                 rtm->rtm_table = (unsigned char)fibnum;
  274         rtm->rtm_scope = RT_SCOPE_UNIVERSE;
  275         rtm->rtm_protocol = nl_get_rtm_protocol(rnd->rnd_nhop);
  276         rtm->rtm_type = get_rtm_type(rnd->rnd_nhop);
  277 
  278         nlattr_add_u32(nw, NL_RTA_TABLE, fibnum);
  279 
  280         int plen = 0;
  281 #if defined(INET) || defined(INET6)
  282         uint32_t scopeid;
  283 #endif
  284         switch (family) {
  285 #ifdef INET
  286         case AF_INET:
  287                 {
  288                         struct in_addr addr;
  289                         rt_get_inet_prefix_plen(rt, &addr, &plen, &scopeid);
  290                         nlattr_add(nw, NL_RTA_DST, 4, &addr);
  291                         break;
  292                 }
  293 #endif
  294 #ifdef INET6
  295         case AF_INET6:
  296                 {
  297                         struct in6_addr addr;
  298                         rt_get_inet6_prefix_plen(rt, &addr, &plen, &scopeid);
  299                         nlattr_add(nw, NL_RTA_DST, 16, &addr);
  300                         break;
  301                 }
  302 #endif
  303         default:
  304                 FIB_LOG(LOG_NOTICE, fibnum, family, "unsupported rt family: %d", family);
  305                 error = EAFNOSUPPORT;
  306                 goto flush;
  307         }
  308 
  309         rtm = nlattr_restore_offset(nw, rtm_off, struct rtmsg);
  310         if (plen > 0)
  311                 rtm->rtm_dst_len = plen;
  312         dump_rc_nhop(nw, rnd->rnd_nhop, rtm);
  313 
  314         if (nlmsg_end(nw))
  315                 return (0);
  316 enomem:
  317         error = ENOMEM;
  318 flush:
  319         nlmsg_abort(nw);
  320         return (error);
  321 }
  322 
  323 static int
  324 family_to_group(int family)
  325 {
  326         switch (family) {
  327         case AF_INET:
  328                 return (RTNLGRP_IPV4_ROUTE);
  329         case AF_INET6:
  330                 return (RTNLGRP_IPV6_ROUTE);
  331         }
  332         return (0);
  333 }
  334 
  335 
  336 static void
  337 report_operation(uint32_t fibnum, struct rib_cmd_info *rc,
  338     struct nlpcb *nlp, struct nlmsghdr *hdr)
  339 {
  340         struct nl_writer nw = {};
  341         uint32_t group_id = family_to_group(rt_get_family(rc->rc_rt));
  342 
  343         if (nlmsg_get_group_writer(&nw, NLMSG_SMALL, NETLINK_ROUTE, group_id)) {
  344                 struct route_nhop_data rnd = {
  345                         .rnd_nhop = rc_get_nhop(rc),
  346                         .rnd_weight = rc->rc_nh_weight,
  347                 };
  348                 hdr->nlmsg_flags &= ~(NLM_F_REPLACE | NLM_F_CREATE);
  349                 hdr->nlmsg_flags &= ~(NLM_F_EXCL | NLM_F_APPEND);
  350                 switch (rc->rc_cmd) {
  351                 case RTM_ADD:
  352                         hdr->nlmsg_type = NL_RTM_NEWROUTE;
  353                         hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_EXCL;
  354                         break;
  355                 case RTM_CHANGE:
  356                         hdr->nlmsg_type = NL_RTM_NEWROUTE;
  357                         hdr->nlmsg_flags |= NLM_F_REPLACE;
  358                         break;
  359                 case RTM_DELETE:
  360                         hdr->nlmsg_type = NL_RTM_DELROUTE;
  361                         break;
  362                 }
  363                 dump_px(fibnum, hdr, rc->rc_rt, &rnd, &nw);
  364                 nlmsg_flush(&nw);
  365         }
  366 
  367         rtsock_callback_p->route_f(fibnum, rc);
  368 }
  369 
  370 struct rta_mpath_nh {
  371         struct sockaddr *gw;
  372         struct ifnet    *ifp;
  373         uint8_t         rtnh_flags;
  374         uint8_t         rtnh_weight;
  375 };
  376 
  377 #define _IN(_field)     offsetof(struct rtnexthop, _field)
  378 #define _OUT(_field)    offsetof(struct rta_mpath_nh, _field)
  379 const static struct nlattr_parser nla_p_rtnh[] = {
  380         { .type = NL_RTA_GATEWAY, .off = _OUT(gw), .cb = nlattr_get_ip },
  381         { .type = NL_RTA_VIA, .off = _OUT(gw), .cb = nlattr_get_ipvia },
  382 };
  383 const static struct nlfield_parser nlf_p_rtnh[] = {
  384         { .off_in = _IN(rtnh_flags), .off_out = _OUT(rtnh_flags), .cb = nlf_get_u8 },
  385         { .off_in = _IN(rtnh_hops), .off_out = _OUT(rtnh_weight), .cb = nlf_get_u8 },
  386         { .off_in = _IN(rtnh_ifindex), .off_out = _OUT(ifp), .cb = nlf_get_ifpz },
  387 };
  388 #undef _IN
  389 #undef _OUT
  390 NL_DECLARE_PARSER(mpath_parser, struct rtnexthop, nlf_p_rtnh, nla_p_rtnh);
  391 
  392 struct rta_mpath {
  393         int num_nhops;
  394         struct rta_mpath_nh nhops[0];
  395 };
  396 
  397 static int
  398 nlattr_get_multipath(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
  399 {
  400         int data_len = nla->nla_len - sizeof(struct nlattr);
  401         struct rtnexthop *rtnh;
  402 
  403         int max_nhops = data_len / sizeof(struct rtnexthop);
  404 
  405         struct rta_mpath *mp = npt_alloc(npt, (max_nhops + 2) * sizeof(struct rta_mpath_nh));
  406         mp->num_nhops = 0;
  407 
  408         for (rtnh = (struct rtnexthop *)(nla + 1); data_len > 0; ) {
  409                 struct rta_mpath_nh *mpnh = &mp->nhops[mp->num_nhops++];
  410 
  411                 int error = nl_parse_header(rtnh, rtnh->rtnh_len, &mpath_parser,
  412                     npt, mpnh);
  413                 if (error != 0) {
  414                         NLMSG_REPORT_ERR_MSG(npt, "RTA_MULTIPATH: nexhop %d: parse failed",
  415                             mp->num_nhops - 1);
  416                         return (error);
  417                 }
  418 
  419                 int len = NL_ITEM_ALIGN(rtnh->rtnh_len);
  420                 data_len -= len;
  421                 rtnh = (struct rtnexthop *)((char *)rtnh + len);
  422         }
  423         if (data_len != 0 || mp->num_nhops == 0) {
  424                 NLMSG_REPORT_ERR_MSG(npt, "invalid RTA_MULTIPATH attr");
  425                 return (EINVAL);
  426         }
  427 
  428         *((struct rta_mpath **)target) = mp;
  429         return (0);
  430 }
  431 
  432 
  433 struct nl_parsed_route {
  434         struct sockaddr         *rta_dst;
  435         struct sockaddr         *rta_gw;
  436         struct ifnet            *rta_oif;
  437         struct rta_mpath        *rta_multipath;
  438         uint32_t                rta_table;
  439         uint32_t                rta_rtflags;
  440         uint32_t                rta_nh_id;
  441         uint32_t                rtax_mtu;
  442         uint8_t                 rtm_family;
  443         uint8_t                 rtm_dst_len;
  444         uint8_t                 rtm_protocol;
  445 };
  446 
  447 #define _IN(_field)     offsetof(struct rtmsg, _field)
  448 #define _OUT(_field)    offsetof(struct nl_parsed_route, _field)
  449 static struct nlattr_parser nla_p_rtmetrics[] = {
  450         { .type = NL_RTAX_MTU, .off = _OUT(rtax_mtu), .cb = nlattr_get_uint32 },
  451 };
  452 NL_DECLARE_ATTR_PARSER(metrics_parser, nla_p_rtmetrics);
  453 
  454 static const struct nlattr_parser nla_p_rtmsg[] = {
  455         { .type = NL_RTA_DST, .off = _OUT(rta_dst), .cb = nlattr_get_ip },
  456         { .type = NL_RTA_OIF, .off = _OUT(rta_oif), .cb = nlattr_get_ifp },
  457         { .type = NL_RTA_GATEWAY, .off = _OUT(rta_gw), .cb = nlattr_get_ip },
  458         { .type = NL_RTA_METRICS, .arg = &metrics_parser, .cb = nlattr_get_nested },
  459         { .type = NL_RTA_MULTIPATH, .off = _OUT(rta_multipath), .cb = nlattr_get_multipath },
  460         { .type = NL_RTA_RTFLAGS, .off = _OUT(rta_rtflags), .cb = nlattr_get_uint32 },
  461         { .type = NL_RTA_TABLE, .off = _OUT(rta_table), .cb = nlattr_get_uint32 },
  462         { .type = NL_RTA_VIA, .off = _OUT(rta_gw), .cb = nlattr_get_ipvia },
  463         { .type = NL_RTA_NH_ID, .off = _OUT(rta_nh_id), .cb = nlattr_get_uint32 },
  464 };
  465 
  466 static const struct nlfield_parser nlf_p_rtmsg[] = {
  467         {.off_in = _IN(rtm_family), .off_out = _OUT(rtm_family), .cb = nlf_get_u8 },
  468         {.off_in = _IN(rtm_dst_len), .off_out = _OUT(rtm_dst_len), .cb = nlf_get_u8 },
  469         {.off_in = _IN(rtm_protocol), .off_out = _OUT(rtm_protocol), .cb = nlf_get_u8 },
  470 };
  471 #undef _IN
  472 #undef _OUT
  473 NL_DECLARE_PARSER(rtm_parser, struct rtmsg, nlf_p_rtmsg, nla_p_rtmsg);
  474 
  475 struct netlink_walkargs {
  476         struct nl_writer *nw;
  477         struct route_nhop_data rnd;
  478         struct nlmsghdr hdr;
  479         struct nlpcb *nlp;
  480         uint32_t fibnum;
  481         int family;
  482         int error;
  483         int count;
  484         int dumped;
  485         int dumped_tables;
  486 };
  487 
  488 static int
  489 dump_rtentry(struct rtentry *rt, void *_arg)
  490 {
  491         struct netlink_walkargs *wa = (struct netlink_walkargs *)_arg;
  492         int error;
  493 
  494         wa->count++;
  495         if (wa->error != 0)
  496                 return (0);
  497         wa->dumped++;
  498 
  499         rt_get_rnd(rt, &wa->rnd);
  500 
  501         error = dump_px(wa->fibnum, &wa->hdr, rt, &wa->rnd, wa->nw);
  502 
  503         IF_DEBUG_LEVEL(LOG_DEBUG3) {
  504                 char rtbuf[INET6_ADDRSTRLEN + 5];
  505                 FIB_LOG(LOG_DEBUG3, wa->fibnum, wa->family,
  506                     "Dump %s, offset %u, error %d",
  507                     rt_print_buf(rt, rtbuf, sizeof(rtbuf)),
  508                     wa->nw->offset, error);
  509         }
  510         wa->error = error;
  511 
  512         return (0);
  513 }
  514 
  515 static void
  516 dump_rtable_one(struct netlink_walkargs *wa, uint32_t fibnum, int family)
  517 {
  518         FIB_LOG(LOG_DEBUG2, fibnum, family, "Start dump");
  519         wa->count = 0;
  520         wa->dumped = 0;
  521 
  522         rib_walk(fibnum, family, false, dump_rtentry, wa);
  523 
  524         wa->dumped_tables++;
  525 
  526         FIB_LOG(LOG_DEBUG2, fibnum, family, "End dump, iterated %d dumped %d",
  527             wa->count, wa->dumped);
  528         NL_LOG(LOG_DEBUG2, "Current offset: %d", wa->nw->offset);
  529 }
  530 
  531 static int
  532 dump_rtable_fib(struct netlink_walkargs *wa, uint32_t fibnum, int family)
  533 {
  534         wa->fibnum = fibnum;
  535 
  536         if (family == AF_UNSPEC) {
  537                 for (int i = 0; i < AF_MAX; i++) {
  538                         if (rt_tables_get_rnh(fibnum, i) != 0) {
  539                                 wa->family = i;
  540                                 dump_rtable_one(wa, fibnum, i);
  541                                 if (wa->error != 0)
  542                                         break;
  543                         }
  544                 }
  545         } else {
  546                 if (rt_tables_get_rnh(fibnum, family) != 0) {
  547                         wa->family = family;
  548                         dump_rtable_one(wa, fibnum, family);
  549                 }
  550         }
  551 
  552         return (wa->error);
  553 }
  554 
  555 static int
  556 handle_rtm_getroute(struct nlpcb *nlp, struct nl_parsed_route *attrs,
  557     struct nlmsghdr *hdr, struct nl_pstate *npt)
  558 {
  559         RIB_RLOCK_TRACKER;
  560         struct rib_head *rnh;
  561         struct rtentry *rt;
  562         uint32_t fibnum = attrs->rta_table;
  563         sa_family_t family = attrs->rtm_family;
  564 
  565         if (attrs->rta_dst == NULL) {
  566                 NLMSG_REPORT_ERR_MSG(npt, "No RTA_DST supplied");
  567                         return (EINVAL);
  568         }
  569 
  570         FIB_LOG(LOG_DEBUG, fibnum, family, "getroute called");
  571 
  572         rnh = rt_tables_get_rnh(fibnum, family);
  573         if (rnh == NULL)
  574                 return (EAFNOSUPPORT);
  575 
  576         RIB_RLOCK(rnh);
  577 
  578         rt = (struct rtentry *)rnh->rnh_matchaddr(attrs->rta_dst, &rnh->head);
  579         if (rt == NULL) {
  580                 RIB_RUNLOCK(rnh);
  581                 return (ESRCH);
  582         }
  583 
  584         struct route_nhop_data rnd;
  585         rt_get_rnd(rt, &rnd);
  586         rnd.rnd_nhop = nhop_select_func(rnd.rnd_nhop, 0);
  587 
  588         RIB_RUNLOCK(rnh);
  589 
  590         IF_DEBUG_LEVEL(LOG_DEBUG2) {
  591                 char rtbuf[NHOP_PRINT_BUFSIZE] __unused, nhbuf[NHOP_PRINT_BUFSIZE] __unused;
  592                 FIB_LOG(LOG_DEBUG2, fibnum, family, "getroute completed: got %s for %s",
  593                     nhop_print_buf_any(rnd.rnd_nhop, nhbuf, sizeof(nhbuf)),
  594                     rt_print_buf(rt, rtbuf, sizeof(rtbuf)));
  595         }
  596 
  597         hdr->nlmsg_type = NL_RTM_NEWROUTE;
  598         dump_px(fibnum, hdr, rt, &rnd, npt->nw);
  599 
  600         return (0);
  601 }
  602 
  603 static int
  604 handle_rtm_dump(struct nlpcb *nlp, uint32_t fibnum, int family,
  605     struct nlmsghdr *hdr, struct nl_writer *nw)
  606 {
  607         struct netlink_walkargs wa = {
  608                 .nlp = nlp,
  609                 .nw = nw,
  610                 .hdr.nlmsg_pid = hdr->nlmsg_pid,
  611                 .hdr.nlmsg_seq = hdr->nlmsg_seq,
  612                 .hdr.nlmsg_type = NL_RTM_NEWROUTE,
  613                 .hdr.nlmsg_flags = hdr->nlmsg_flags | NLM_F_MULTI,
  614         };
  615 
  616         if (fibnum == RT_TABLE_UNSPEC) {
  617                 for (int i = 0; i < V_rt_numfibs; i++) {
  618                         dump_rtable_fib(&wa, fibnum, family);
  619                         if (wa.error != 0)
  620                                 break;
  621                 }
  622         } else
  623                 dump_rtable_fib(&wa, fibnum, family);
  624 
  625         if (wa.error == 0 && wa.dumped_tables == 0) {
  626                 FIB_LOG(LOG_DEBUG, fibnum, family, "incorrect fibnum/family");
  627                 wa.error = ESRCH;
  628                 // How do we propagate it?
  629         }
  630 
  631         if (!nlmsg_end_dump(wa.nw, wa.error, &wa.hdr)) {
  632                 NL_LOG(LOG_DEBUG, "Unable to finalize the dump");
  633                 return (ENOMEM);
  634         }
  635 
  636         return (wa.error);
  637 }
  638 
  639 static struct nhop_object *
  640 finalize_nhop(struct nhop_object *nh, int *perror)
  641 {
  642         /*
  643          * The following MUST be filled:
  644          *  nh_ifp, nh_ifa, nh_gw
  645          */
  646         if (nh->gw_sa.sa_family == 0) {
  647                 /*
  648                  * Empty gateway. Can be direct route with RTA_OIF set.
  649                  */
  650                 if (nh->nh_ifp != NULL)
  651                         nhop_set_direct_gw(nh, nh->nh_ifp);
  652                 else {
  653                         NL_LOG(LOG_DEBUG, "empty gateway and interface, skipping");
  654                         *perror = EINVAL;
  655                         return (NULL);
  656                 }
  657                 /* Both nh_ifp and gateway are set */
  658         } else {
  659                 /* Gateway is set up, we can derive ifp if not set */
  660                 if (nh->nh_ifp == NULL) {
  661                         struct ifaddr *ifa = ifa_ifwithnet(&nh->gw_sa, 1, nhop_get_fibnum(nh));
  662                         if (ifa == NULL) {
  663                                 NL_LOG(LOG_DEBUG, "Unable to determine ifp, skipping");
  664                                 *perror = EINVAL;
  665                                 return (NULL);
  666                         }
  667                         nhop_set_transmit_ifp(nh, ifa->ifa_ifp);
  668                 }
  669         }
  670         /* Both nh_ifp and gateway are set */
  671         if (nh->nh_ifa == NULL) {
  672                 struct ifaddr *ifa = ifaof_ifpforaddr(&nh->gw_sa, nh->nh_ifp);
  673                 if (ifa == NULL) {
  674                         NL_LOG(LOG_DEBUG, "Unable to determine ifa, skipping");
  675                         *perror = EINVAL;
  676                         return (NULL);
  677                 }
  678                 nhop_set_src(nh, ifa);
  679         }
  680 
  681         return (nhop_get_nhop(nh, perror));
  682 }
  683 
  684 static int
  685 get_pxflag(const struct nl_parsed_route *attrs)
  686 {
  687         int pxflag = 0;
  688         switch (attrs->rtm_family) {
  689         case AF_INET:
  690                 if (attrs->rtm_dst_len == 32)
  691                         pxflag = NHF_HOST;
  692                 else if (attrs->rtm_dst_len == 0)
  693                         pxflag = NHF_DEFAULT;
  694                 break;
  695         case AF_INET6:
  696                 if (attrs->rtm_dst_len == 32)
  697                         pxflag = NHF_HOST;
  698                 else if (attrs->rtm_dst_len == 0)
  699                         pxflag = NHF_DEFAULT;
  700                 break;
  701         }
  702 
  703         return (pxflag);
  704 }
  705 
  706 static int
  707 get_op_flags(int nlm_flags)
  708 {
  709         int op_flags = 0;
  710 
  711         op_flags |= (nlm_flags & NLM_F_REPLACE) ? RTM_F_REPLACE : 0;
  712         op_flags |= (nlm_flags & NLM_F_EXCL) ? RTM_F_EXCL : 0;
  713         op_flags |= (nlm_flags & NLM_F_CREATE) ? RTM_F_CREATE : 0;
  714         op_flags |= (nlm_flags & NLM_F_APPEND) ? RTM_F_APPEND : 0;
  715 
  716         return (op_flags);
  717 }
  718 
  719 #ifdef ROUTE_MPATH
  720 static int
  721 create_nexthop_one(struct nl_parsed_route *attrs, struct rta_mpath_nh *mpnh,
  722     struct nl_pstate *npt, struct nhop_object **pnh)
  723 {
  724         int error;
  725 
  726         if (mpnh->gw == NULL)
  727                 return (EINVAL);
  728 
  729         struct nhop_object *nh = nhop_alloc(attrs->rta_table, attrs->rtm_family);
  730         if (nh == NULL)
  731                 return (ENOMEM);
  732 
  733         nhop_set_gw(nh, mpnh->gw, true);
  734         if (mpnh->ifp != NULL)
  735                 nhop_set_transmit_ifp(nh, mpnh->ifp);
  736         nhop_set_rtflags(nh, attrs->rta_rtflags);
  737         if (attrs->rtm_protocol > RTPROT_STATIC)
  738                 nhop_set_origin(nh, attrs->rtm_protocol);
  739 
  740         *pnh = finalize_nhop(nh, &error);
  741 
  742         return (error);
  743 }
  744 #endif
  745 
  746 static struct nhop_object *
  747 create_nexthop_from_attrs(struct nl_parsed_route *attrs,
  748     struct nl_pstate *npt, int *perror)
  749 {
  750         struct nhop_object *nh = NULL;
  751         int error = 0;
  752 
  753         if (attrs->rta_multipath != NULL) {
  754 #ifdef ROUTE_MPATH
  755                 /* Multipath w/o explicit nexthops */
  756                 int num_nhops = attrs->rta_multipath->num_nhops;
  757                 struct weightened_nhop *wn = npt_alloc(npt, sizeof(*wn) * num_nhops);
  758 
  759                 for (int i = 0; i < num_nhops; i++) {
  760                         struct rta_mpath_nh *mpnh = &attrs->rta_multipath->nhops[i];
  761 
  762                         error = create_nexthop_one(attrs, mpnh, npt, &wn[i].nh);
  763                         if (error != 0) {
  764                                 for (int j = 0; j < i; j++)
  765                                         nhop_free(wn[j].nh);
  766                                 break;
  767                         }
  768                         wn[i].weight = mpnh->rtnh_weight > 0 ? mpnh->rtnh_weight : 1;
  769                 }
  770                 if (error == 0) {
  771                         struct rib_head *rh = nhop_get_rh(wn[0].nh);
  772                         struct nhgrp_object *nhg;
  773 
  774                         nhg = nhgrp_alloc(rh->rib_fibnum, rh->rib_family,
  775                             wn, num_nhops, perror);
  776                         if (nhg != NULL) {
  777                                 if (attrs->rtm_protocol > RTPROT_STATIC)
  778                                         nhgrp_set_origin(nhg, attrs->rtm_protocol);
  779                                 nhg = nhgrp_get_nhgrp(nhg, perror);
  780                         }
  781                         for (int i = 0; i < num_nhops; i++)
  782                                 nhop_free(wn[i].nh);
  783                         if (nhg != NULL)
  784                                 return ((struct nhop_object *)nhg);
  785                         error = *perror;
  786                 }
  787 #else
  788                 error = ENOTSUP;
  789 #endif
  790                 *perror = error;
  791         } else {
  792                 nh = nhop_alloc(attrs->rta_table, attrs->rtm_family);
  793                 if (nh == NULL) {
  794                         *perror = ENOMEM;
  795                         return (NULL);
  796                 }
  797                 if (attrs->rta_gw != NULL)
  798                         nhop_set_gw(nh, attrs->rta_gw, true);
  799                 if (attrs->rta_oif != NULL)
  800                         nhop_set_transmit_ifp(nh, attrs->rta_oif);
  801                 if (attrs->rtax_mtu != 0)
  802                         nhop_set_mtu(nh, attrs->rtax_mtu, true);
  803                 if (attrs->rta_rtflags & RTF_BROADCAST)
  804                         nhop_set_broadcast(nh, true);
  805                 if (attrs->rta_rtflags & RTF_BLACKHOLE)
  806                         nhop_set_blackhole(nh, NHF_BLACKHOLE);
  807                 if (attrs->rta_rtflags & RTF_REJECT)
  808                         nhop_set_blackhole(nh, NHF_REJECT);
  809                 nhop_set_rtflags(nh, attrs->rta_rtflags);
  810                 if (attrs->rtm_protocol > RTPROT_STATIC)
  811                         nhop_set_origin(nh, attrs->rtm_protocol);
  812                 nh = finalize_nhop(nh, perror);
  813         }
  814 
  815         return (nh);
  816 }
  817 
  818 static int
  819 rtnl_handle_newroute(struct nlmsghdr *hdr, struct nlpcb *nlp,
  820     struct nl_pstate *npt)
  821 {
  822         struct rib_cmd_info rc = {};
  823         struct nhop_object *nh = NULL;
  824         int error;
  825 
  826         struct nl_parsed_route attrs = {};
  827         error = nl_parse_nlmsg(hdr, &rtm_parser, npt, &attrs);
  828         if (error != 0)
  829                 return (error);
  830 
  831         /* Check if we have enough data */
  832         if (attrs.rta_dst == NULL) {
  833                 NL_LOG(LOG_DEBUG, "missing RTA_DST");
  834                 return (EINVAL);
  835         }
  836 
  837         if (attrs.rta_nh_id != 0) {
  838                 /* Referenced uindex */
  839                 int pxflag = get_pxflag(&attrs);
  840                 nh = nl_find_nhop(attrs.rta_table, attrs.rtm_family, attrs.rta_nh_id,
  841                     pxflag, &error);
  842                 if (error != 0)
  843                         return (error);
  844         } else {
  845                 nh = create_nexthop_from_attrs(&attrs, npt, &error);
  846                 if (error != 0) {
  847                         NL_LOG(LOG_DEBUG, "Error creating nexthop");
  848                         return (error);
  849                 }
  850         }
  851 
  852         int weight = NH_IS_NHGRP(nh) ? 0 : RT_DEFAULT_WEIGHT;
  853         struct route_nhop_data rnd = { .rnd_nhop = nh, .rnd_weight = weight };
  854         int op_flags = get_op_flags(hdr->nlmsg_flags);
  855 
  856         error = rib_add_route_px(attrs.rta_table, attrs.rta_dst, attrs.rtm_dst_len,
  857             &rnd, op_flags, &rc);
  858         if (error == 0)
  859                 report_operation(attrs.rta_table, &rc, nlp, hdr);
  860         return (error);
  861 }
  862 
  863 static int
  864 path_match_func(const struct rtentry *rt, const struct nhop_object *nh, void *_data)
  865 {
  866         struct nl_parsed_route *attrs = (struct nl_parsed_route *)_data;
  867 
  868         if ((attrs->rta_gw != NULL) && !rib_match_gw(rt, nh, attrs->rta_gw))
  869                 return (0);
  870 
  871         if ((attrs->rta_oif != NULL) && (attrs->rta_oif != nh->nh_ifp))
  872                 return (0);
  873 
  874         return (1);
  875 }
  876 
  877 static int
  878 rtnl_handle_delroute(struct nlmsghdr *hdr, struct nlpcb *nlp,
  879     struct nl_pstate *npt)
  880 {
  881         struct rib_cmd_info rc;
  882         int error;
  883 
  884         struct nl_parsed_route attrs = {};
  885         error = nl_parse_nlmsg(hdr, &rtm_parser, npt, &attrs);
  886         if (error != 0)
  887                 return (error);
  888 
  889         if (attrs.rta_dst == NULL) {
  890                 NLMSG_REPORT_ERR_MSG(npt, "RTA_DST is not set");
  891                 return (ESRCH);
  892         }
  893 
  894         error = rib_del_route_px(attrs.rta_table, attrs.rta_dst,
  895             attrs.rtm_dst_len, path_match_func, &attrs, 0, &rc);
  896         if (error == 0)
  897                 report_operation(attrs.rta_table, &rc, nlp, hdr);
  898         return (error);
  899 }
  900 
  901 static int
  902 rtnl_handle_getroute(struct nlmsghdr *hdr, struct nlpcb *nlp, struct nl_pstate *npt)
  903 {
  904         int error;
  905 
  906         struct nl_parsed_route attrs = {};
  907         error = nl_parse_nlmsg(hdr, &rtm_parser, npt, &attrs);
  908         if (error != 0)
  909                 return (error);
  910 
  911         if (hdr->nlmsg_flags & NLM_F_DUMP)
  912                 error = handle_rtm_dump(nlp, attrs.rta_table, attrs.rtm_family, hdr, npt->nw);
  913         else
  914                 error = handle_rtm_getroute(nlp, &attrs, hdr, npt);
  915 
  916         return (error);
  917 }
  918 
  919 void
  920 rtnl_handle_route_event(uint32_t fibnum, const struct rib_cmd_info *rc)
  921 {
  922         struct nl_writer nw = {};
  923         int family, nlm_flags = 0;
  924 
  925         family = rt_get_family(rc->rc_rt);
  926 
  927         /* XXX: check if there are active listeners first */
  928 
  929         /* TODO: consider passing PID/type/seq */
  930         switch (rc->rc_cmd) {
  931         case RTM_ADD:
  932                 nlm_flags = NLM_F_EXCL | NLM_F_CREATE;
  933                 break;
  934         case RTM_CHANGE:
  935                 nlm_flags = NLM_F_REPLACE;
  936                 break;
  937         case RTM_DELETE:
  938                 nlm_flags = 0;
  939                 break;
  940         }
  941         IF_DEBUG_LEVEL(LOG_DEBUG2) {
  942                 char rtbuf[NHOP_PRINT_BUFSIZE] __unused;
  943                 FIB_LOG(LOG_DEBUG2, fibnum, family,
  944                     "received event %s for %s / nlm_flags=%X",
  945                     rib_print_cmd(rc->rc_cmd),
  946                     rt_print_buf(rc->rc_rt, rtbuf, sizeof(rtbuf)),
  947                     nlm_flags);
  948         }
  949 
  950         struct nlmsghdr hdr = {
  951                 .nlmsg_flags = nlm_flags,
  952                 .nlmsg_type = get_rtmsg_type_from_rtsock(rc->rc_cmd),
  953         };
  954 
  955         struct route_nhop_data rnd = {
  956                 .rnd_nhop = rc_get_nhop(rc),
  957                 .rnd_weight = rc->rc_nh_weight,
  958         };
  959 
  960         uint32_t group_id = family_to_group(family);
  961         if (!nlmsg_get_group_writer(&nw, NLMSG_SMALL, NETLINK_ROUTE, group_id)) {
  962                 NL_LOG(LOG_DEBUG, "error allocating event buffer");
  963                 return;
  964         }
  965 
  966         dump_px(fibnum, &hdr, rc->rc_rt, &rnd, &nw);
  967         nlmsg_flush(&nw);
  968 }
  969 
  970 static const struct rtnl_cmd_handler cmd_handlers[] = {
  971         {
  972                 .cmd = NL_RTM_GETROUTE,
  973                 .name = "RTM_GETROUTE",
  974                 .cb = &rtnl_handle_getroute,
  975         },
  976         {
  977                 .cmd = NL_RTM_DELROUTE,
  978                 .name = "RTM_DELROUTE",
  979                 .cb = &rtnl_handle_delroute,
  980                 .priv = PRIV_NET_ROUTE,
  981         },
  982         {
  983                 .cmd = NL_RTM_NEWROUTE,
  984                 .name = "RTM_NEWROUTE",
  985                 .cb = &rtnl_handle_newroute,
  986                 .priv = PRIV_NET_ROUTE,
  987         }
  988 };
  989 
  990 static const struct nlhdr_parser *all_parsers[] = {&mpath_parser, &metrics_parser, &rtm_parser};
  991 
  992 void
  993 rtnl_routes_init(void)
  994 {
  995         NL_VERIFY_PARSERS(all_parsers);
  996         rtnl_register_messages(cmd_handlers, NL_ARRAY_LEN(cmd_handlers));
  997 }

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