FreeBSD/Linux Kernel Cross Reference
sys/netinet/in_fib.c

     /*-
      * Copyright (c) 2015
      *      Alexander V. Chernikov <melifaro@FreeBSD.org>
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include "opt_inet.h"
    #include "opt_route.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/lock.h>
    #include <sys/rmlock.h>
    #include <sys/malloc.h>
    #include <sys/mbuf.h>
    #include <sys/socket.h>
    #include <sys/sysctl.h>
    #include <sys/kernel.h>
    
    #include <net/if.h>
    #include <net/if_var.h>
    #include <net/if_dl.h>
    #include <net/route.h>
    #include <net/route/route_ctl.h>
    #include <net/route/route_var.h>
    #include <net/route/fib_algo.h>
    #include <net/route/nhop.h>
    #include <net/toeplitz.h>
    #include <net/vnet.h>
    
    #include <netinet/in.h>
    #include <netinet/in_var.h>
    #include <netinet/in_fib.h>
    
    #ifdef INET
    
    /* Verify struct route compatibility */
    /* Assert 'struct route_in' is compatible with 'struct route' */
    CHK_STRUCT_ROUTE_COMPAT(struct route_in, ro_dst4);
    
    #ifdef FIB_ALGO
    VNET_DEFINE(struct fib_dp *, inet_dp);
    #endif
    
    #ifdef ROUTE_MPATH
    struct _hash_5tuple_ipv4 {
            struct in_addr src;
            struct in_addr dst;
            unsigned short src_port;
            unsigned short dst_port;
            char proto;
            char spare[3];
    };
    _Static_assert(sizeof(struct _hash_5tuple_ipv4) == 16,
        "_hash_5tuple_ipv4 size is wrong");
    
    uint32_t
    fib4_calc_software_hash(struct in_addr src, struct in_addr dst,
        unsigned short src_port, unsigned short dst_port, char proto,
        uint32_t *phashtype)
    {
            struct _hash_5tuple_ipv4 data;
    
            data.src = src;
            data.dst = dst;
            data.src_port = src_port;
            data.dst_port = dst_port;
            data.proto = proto;
            data.spare[0] = data.spare[1] = data.spare[2] = 0;
    
            *phashtype = M_HASHTYPE_OPAQUE;
    
            return (toeplitz_hash(MPATH_ENTROPY_KEY_LEN, mpath_entropy_key,
             sizeof(data), (uint8_t *)&data));
   }
   #endif
   
   /*
    * Looks up path in fib @fibnum specified by @dst.
    * Returns path nexthop on success. Nexthop is safe to use
    *  within the current network epoch. If longer lifetime is required,
    *  one needs to pass NHR_REF as a flag. This will return referenced
    *  nexthop.
    */
   #ifdef FIB_ALGO
   struct nhop_object *
   fib4_lookup(uint32_t fibnum, struct in_addr dst, uint32_t scopeid,
       uint32_t flags, uint32_t flowid)
   {
           struct nhop_object *nh;
           struct fib_dp *dp = &V_inet_dp[fibnum];
           struct flm_lookup_key key = {.addr4 = dst };
   
           nh = dp->f(dp->arg, key, scopeid);
           if (nh != NULL) {
                   nh = nhop_select(nh, flowid);
                   /* Ensure route & ifp is UP */
                   if (RT_LINK_IS_UP(nh->nh_ifp)) {
                           if (flags & NHR_REF)
                                   nhop_ref_object(nh);
                           return (nh);
                   }
           }
           RTSTAT_INC(rts_unreach);
           return (NULL);
   }
   #else
   struct nhop_object *
   fib4_lookup(uint32_t fibnum, struct in_addr dst, uint32_t scopeid,
       uint32_t flags, uint32_t flowid)
   {
           RIB_RLOCK_TRACKER;
           struct rib_head *rh;
           struct radix_node *rn;
           struct nhop_object *nh;
   
           KASSERT((fibnum < rt_numfibs), ("fib4_lookup: bad fibnum"));
           rh = rt_tables_get_rnh(fibnum, AF_INET);
           if (rh == NULL)
                   return (NULL);
   
           /* Prepare lookup key */
           struct sockaddr_in sin4 = {
                   .sin_family = AF_INET,
                   .sin_len = sizeof(struct sockaddr_in),
                   .sin_addr = dst,
           };
   
           nh = NULL;
           RIB_RLOCK(rh);
           rn = rh->rnh_matchaddr((void *)&sin4, &rh->head);
           if (rn != NULL && ((rn->rn_flags & RNF_ROOT) == 0)) {
                   nh = nhop_select((RNTORT(rn))->rt_nhop, flowid);
                   /* Ensure route & ifp is UP */
                   if (RT_LINK_IS_UP(nh->nh_ifp)) {
                           if (flags & NHR_REF)
                                   nhop_ref_object(nh);
                           RIB_RUNLOCK(rh);
                           return (nh);
                   }
           }
           RIB_RUNLOCK(rh);
   
           RTSTAT_INC(rts_unreach);
           return (NULL);
   }
   #endif
   
   inline static int
   check_urpf_nhop(const struct nhop_object *nh, uint32_t flags,
       const struct ifnet *src_if)
   {
   
           if (src_if != NULL && nh->nh_aifp == src_if) {
                   return (1);
           }
           if (src_if == NULL) {
                   if ((flags & NHR_NODEFAULT) == 0)
                           return (1);
                   else if ((nh->nh_flags & NHF_DEFAULT) == 0)
                           return (1);
           }
   
           return (0);
   }
   
   static int
   check_urpf(struct nhop_object *nh, uint32_t flags,
       const struct ifnet *src_if)
   {
   #ifdef ROUTE_MPATH
           if (NH_IS_NHGRP(nh)) {
                   const struct weightened_nhop *wn;
                   uint32_t num_nhops;
                   wn = nhgrp_get_nhops((struct nhgrp_object *)nh, &num_nhops);
                           for (int i = 0; i < num_nhops; i++) {
                                   if (check_urpf_nhop(wn[i].nh, flags, src_if) != 0)
                                   return (1);
                   }
                   return (0);
           } else
   #endif
                   return (check_urpf_nhop(nh, flags, src_if));
   }
   
   #ifndef FIB_ALGO
   static struct nhop_object *
   lookup_nhop(uint32_t fibnum, struct in_addr dst, uint32_t scopeid)
   {
           RIB_RLOCK_TRACKER;
           struct rib_head *rh;
           struct radix_node *rn;
           struct nhop_object *nh;
   
           KASSERT((fibnum < rt_numfibs), ("fib4_check_urpf: bad fibnum"));
           rh = rt_tables_get_rnh(fibnum, AF_INET);
           if (rh == NULL)
                   return (NULL);
   
           /* Prepare lookup key */
           struct sockaddr_in sin4;
           memset(&sin4, 0, sizeof(sin4));
           sin4.sin_len = sizeof(struct sockaddr_in);
           sin4.sin_addr = dst;
   
           nh = NULL;
           RIB_RLOCK(rh);
           rn = rh->rnh_matchaddr((void *)&sin4, &rh->head);
           if (rn != NULL && ((rn->rn_flags & RNF_ROOT) == 0))
                   nh = RNTORT(rn)->rt_nhop;
           RIB_RUNLOCK(rh);
   
           return (nh);
   }
   #endif
   
   /*
    * Performs reverse path forwarding lookup.
    * If @src_if is non-zero, verifies that at least 1 path goes via
    *   this interface.
    * If @src_if is zero, verifies that route exist.
    * if @flags contains NHR_NOTDEFAULT, do not consider default route.
    *
    * Returns 1 if route matching conditions is found, 0 otherwise.
    */
   int
   fib4_check_urpf(uint32_t fibnum, struct in_addr dst, uint32_t scopeid,
     uint32_t flags, const struct ifnet *src_if)
   {
           struct nhop_object *nh;
   #ifdef FIB_ALGO
           struct fib_dp *dp = &V_inet_dp[fibnum];
           struct flm_lookup_key key = {.addr4 = dst };
   
           nh = dp->f(dp->arg, key, scopeid);
   #else
           nh = lookup_nhop(fibnum, dst, scopeid);
   #endif
           if (nh != NULL)
                   return (check_urpf(nh, flags, src_if));
   
           return (0);
   }
   
   /*
    * Function returning prefix match data along with the nexthop data.
    * Intended to be used by the control plane code.
    * Supported flags:
    *  NHR_UNLOCKED: do not lock radix during lookup.
    * Returns pointer to rtentry and raw nexthop in @rnd. Both rtentry
    *  and nexthop are safe to use within current epoch. Note:
    * Note: rnd_nhop can actually be the nexthop group.
    */
   struct rtentry *
   fib4_lookup_rt(uint32_t fibnum, struct in_addr dst, uint32_t scopeid,
       uint32_t flags, struct route_nhop_data *rnd)
   {
           RIB_RLOCK_TRACKER;
           struct rib_head *rh;
           struct radix_node *rn;
           struct rtentry *rt;
   
           KASSERT((fibnum < rt_numfibs), ("fib4_lookup_rt: bad fibnum"));
           rh = rt_tables_get_rnh(fibnum, AF_INET);
           if (rh == NULL)
                   return (NULL);
   
           /* Prepare lookup key */
           struct sockaddr_in sin4 = {
                   .sin_family = AF_INET,
                   .sin_len = sizeof(struct sockaddr_in),
                   .sin_addr = dst,
           };
   
           rt = NULL;
           if (!(flags & NHR_UNLOCKED))
                   RIB_RLOCK(rh);
           rn = rh->rnh_matchaddr((void *)&sin4, &rh->head);
           if (rn != NULL && ((rn->rn_flags & RNF_ROOT) == 0)) {
                   rt = (struct rtentry *)rn;
                   rnd->rnd_nhop = rt->rt_nhop;
                   rnd->rnd_weight = rt->rt_weight;
           }
           if (!(flags & NHR_UNLOCKED))
                   RIB_RUNLOCK(rh);
   
           return (rt);
   }
   
   struct nhop_object *
   fib4_lookup_debugnet(uint32_t fibnum, struct in_addr dst, uint32_t scopeid,
       uint32_t flags)
   {
           struct rtentry *rt;
           struct route_nhop_data rnd;
   
           rt = fib4_lookup_rt(fibnum, dst, scopeid, NHR_UNLOCKED, &rnd);
           if (rt != NULL) {
                   struct nhop_object *nh = nhop_select(rnd.rnd_nhop, 0);
                   /* Ensure route & ifp is UP */
                   if (RT_LINK_IS_UP(nh->nh_ifp))
                           return (nh);
           }
   
           return (NULL);
   }
   
   #endif

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