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bird/sysdep/bsd/krt-sock.c
Ondrej Zajicek (work) a39cd2cc0b BSD: Assume onlink flag on ifaces with only host addresses 
The BSD kernel does not support the onlink flag and BIRD does not use
direct routes for next hop validation, instead depends on interface
address ranges. We would like to handle PtMP cases with only host
addresses configured, like:

  ifconfig wg0 192.168.0.10/32
  route add 192.168.0.4 -iface wg0
  route add 192.168.0.8 -iface wg0

To accept BIRD routes with onlink next-hop, like:

  route 192.168.42.0/24 via 192.168.0.4%wg0 onlink

BIRD would dismiss the route when receiving from the kernel, as the
next-hop 192.168.0.4 is not part of any interface subnet and onlink
flag is not kept by the BSD kernel.

The commit fixes this by assuming that for routes received from the
kernel, any next-hop is onlink on ifaces with only host addresses.

Thanks to Stefan Haller for the original patch.
2021-12-27 21:00:04 +01:00

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/*
* BIRD -- BSD Routing Table Syncing
*
* (c) 2004 Ondrej Filip <feela@network.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <net/route.h>
#include <net/if.h>
#include <net/if_dl.h>
#undef LOCAL_DEBUG
#include "nest/bird.h"
#include "nest/iface.h"
#include "nest/route.h"
#include "nest/protocol.h"
#include "nest/iface.h"
#include "sysdep/unix/unix.h"
#include "sysdep/unix/krt.h"
#include "lib/string.h"
#include "lib/socket.h"
const int rt_default_ecmp = 0;
/*
* There are significant differences in multiple tables support between BSD variants.
*
* OpenBSD has table_id field for routes in route socket protocol, therefore all
* tables could be managed by one kernel socket. FreeBSD lacks such field,
* therefore multiple sockets (locked to specific table using SO_SETFIB socket
* option) must be used.
*
* Both FreeBSD and OpenBSD uses separate scans for each table. In OpenBSD,
* table_id is specified explicitly as sysctl scan argument, while in FreeBSD it
* is handled implicitly by changing default table using setfib() syscall.
*
* KRT_SHARED_SOCKET - use shared kernel socked instead of one for each krt_proto
* KRT_USE_SETFIB_SCAN - use setfib() for sysctl() route scan
* KRT_USE_SETFIB_SOCK - use SO_SETFIB socket option for kernel sockets
* KRT_USE_SYSCTL_7 - use 7-th arg of sysctl() as table id for route scans
* KRT_USE_SYSCTL_NET_FIBS - use net.fibs sysctl() for dynamic max number of fibs
*/
#ifdef __FreeBSD__
#define KRT_MAX_TABLES 256
#define KRT_USE_SETFIB_SCAN
#define KRT_USE_SETFIB_SOCK
#define KRT_USE_SYSCTL_NET_FIBS
#endif
#ifdef __OpenBSD__
#define KRT_MAX_TABLES (RT_TABLEID_MAX+1)
#define KRT_SHARED_SOCKET
#define KRT_USE_SYSCTL_7
#endif
#ifndef KRT_MAX_TABLES
#define KRT_MAX_TABLES 1
#endif
/* Dynamic max number of tables */
uint krt_max_tables;
#ifdef KRT_USE_SYSCTL_NET_FIBS
static uint
krt_get_max_tables(void)
{
int fibs;
size_t fibs_len = sizeof(fibs);
if (sysctlbyname("net.fibs", &fibs, &fibs_len, NULL, 0) < 0)
{
log(L_WARN "KRT: unable to get max number of fib tables: %m");
return 1;
}
/* Should not happen */
if (fibs < 1)
return 1;
return (uint) MIN(fibs, KRT_MAX_TABLES);
}
#else
static int
krt_get_max_tables(void)
{
return KRT_MAX_TABLES;
}
#endif /* KRT_USE_SYSCTL_NET_FIBS */
/* setfib() syscall for FreeBSD scans */
#ifdef KRT_USE_SETFIB_SCAN
/*
static int krt_default_fib;
static int
krt_get_active_fib(void)
{
int fib;
size_t fib_len = sizeof(fib);
if (sysctlbyname("net.my_fibnum", &fib, &fib_len, NULL, 0) < 0)
{
log(L_WARN "KRT: unable to get active fib number: %m");
return 0;
}
return fib;
}
*/
extern int setfib(int fib);
#endif /* KRT_USE_SETFIB_SCAN */
/* table_id -> krt_proto map */
#ifdef KRT_SHARED_SOCKET
static struct krt_proto *krt_table_map[KRT_MAX_TABLES][2];
#endif
/* Route socket message processing */
int
krt_capable(rte *e)
{
rta *a = e->attrs;
return
((a->dest == RTD_UNICAST && !a->nh.next) /* No multipath support */
#ifdef RTF_REJECT
|| a->dest == RTD_UNREACHABLE
#endif
#ifdef RTF_BLACKHOLE
|| a->dest == RTD_BLACKHOLE
#endif
);
}
#ifndef RTAX_MAX
#define RTAX_MAX 8
#endif
struct ks_msg
{
struct rt_msghdr rtm;
struct sockaddr_storage buf[RTAX_MAX];
} PACKED;
#define ROUNDUP(a) \
((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
#define NEXTADDR(w, u) \
if (msg.rtm.rtm_addrs & (w)) {\
l = ROUNDUP(((struct sockaddr *)&(u))->sa_len);\
memmove(body, &(u), l); body += l;}
#define GETADDR(p, F) \
bzero(p, sizeof(*p));\
if ((addrs & (F)) && ((struct sockaddr *)body)->sa_len) {\
uint l = ROUNDUP(((struct sockaddr *)body)->sa_len);\
memcpy(p, body, (l > sizeof(*p) ? sizeof(*p) : l));\
body += l;}
static inline void
sockaddr_fill_dl(struct sockaddr_dl *sa, struct iface *ifa)
{
uint len = OFFSETOF(struct sockaddr_dl, sdl_data);
memset(sa, 0, len);
sa->sdl_len = len;
sa->sdl_family = AF_LINK;
sa->sdl_index = ifa->index;
}
static int
krt_send_route(struct krt_proto *p, int cmd, rte *e)
{
net *net = e->net;
rta *a = e->attrs;
static int msg_seq;
struct iface *j, *i = a->nh.iface;
int l;
struct ks_msg msg;
char *body = (char *)msg.buf;
sockaddr gate, mask, dst;
DBG("krt-sock: send %I/%d via %I\n", net->n.prefix, net->n.pxlen, a->gw);
bzero(&msg,sizeof (struct rt_msghdr));
msg.rtm.rtm_version = RTM_VERSION;
msg.rtm.rtm_type = cmd;
msg.rtm.rtm_seq = msg_seq++;
msg.rtm.rtm_addrs = RTA_DST;
msg.rtm.rtm_flags = RTF_UP | RTF_PROTO1;
/* XXXX */
if (net_pxlen(net->n.addr) == net_max_prefix_length[net->n.addr->type])
msg.rtm.rtm_flags |= RTF_HOST;
else
msg.rtm.rtm_addrs |= RTA_NETMASK;
#ifdef KRT_SHARED_SOCKET
msg.rtm.rtm_tableid = KRT_CF->sys.table_id;
#endif
#ifdef RTF_REJECT
if(a->dest == RTD_UNREACHABLE)
msg.rtm.rtm_flags |= RTF_REJECT;
#endif
#ifdef RTF_BLACKHOLE
if(a->dest == RTD_BLACKHOLE)
msg.rtm.rtm_flags |= RTF_BLACKHOLE;
#endif
/*
* This is really very nasty, but I'm not able to add reject/blackhole route
* without gateway address.
*/
if (!i)
{
WALK_LIST(j, iface_list)
{
if (j->flags & IF_LOOPBACK)
{
i = j;
break;
}
}
if (!i)
{
log(L_ERR "KRT: Cannot find loopback iface");
return -1;
}
}
int af = AF_UNSPEC;
switch (net->n.addr->type) {
case NET_IP4:
af = AF_INET;
break;
case NET_IP6:
af = AF_INET6;
break;
default:
log(L_ERR "KRT: Not sending route %N to kernel", net->n.addr);
return -1;
}
sockaddr_fill(&dst, af, net_prefix(net->n.addr), NULL, 0);
sockaddr_fill(&mask, af, net_pxmask(net->n.addr), NULL, 0);
switch (a->dest)
{
case RTD_UNICAST:
if (ipa_nonzero(a->nh.gw))
{
ip_addr gw = a->nh.gw;
/* Embed interface ID to link-local address */
if (ipa_is_link_local(gw))
_I0(gw) = 0xfe800000 | (i->index & 0x0000ffff);
sockaddr_fill(&gate, af, gw, NULL, 0);
msg.rtm.rtm_flags |= RTF_GATEWAY;
msg.rtm.rtm_addrs |= RTA_GATEWAY;
break;
}
#ifdef RTF_REJECT
case RTD_UNREACHABLE:
#endif
#ifdef RTF_BLACKHOLE
case RTD_BLACKHOLE:
#endif
{
/* Fallback for all other valid cases */
#if __OpenBSD__
/* Keeping temporarily old code for OpenBSD */
struct ifa *addr = (net->n.addr->type == NET_IP4) ? i->addr4 : (i->addr6 ?: i->llv6);
if (!addr)
{
log(L_ERR "KRT: interface %s has no IP addess", i->name);
return -1;
}
/* Embed interface ID to link-local address */
ip_addr gw = addr->ip;
if (ipa_is_link_local(gw))
_I0(gw) = 0xfe800000 | (i->index & 0x0000ffff);
sockaddr_fill(&gate, af, gw, i, 0);
#else
sockaddr_fill_dl(&gate, i);
#endif
msg.rtm.rtm_addrs |= RTA_GATEWAY;
break;
}
default:
bug("krt-sock: unknown flags, but not filtered");
}
msg.rtm.rtm_index = i->index;
NEXTADDR(RTA_DST, dst);
NEXTADDR(RTA_GATEWAY, gate);
NEXTADDR(RTA_NETMASK, mask);
l = body - (char *)&msg;
msg.rtm.rtm_msglen = l;
if ((l = write(p->sys.sk->fd, (char *)&msg, l)) < 0) {
log(L_ERR "KRT: Error sending route %N to kernel: %m", net->n.addr);
return -1;
}
return 0;
}
void
krt_replace_rte(struct krt_proto *p, net *n, rte *new, rte *old)
{
int err = 0;
if (old)
krt_send_route(p, RTM_DELETE, old);
if (new)
err = krt_send_route(p, RTM_ADD, new);
if (new)
{
if (err < 0)
bmap_clear(&p->sync_map, new->id);
else
bmap_set(&p->sync_map, new->id);
}
}
/**
* krt_assume_onlink - check if routes on interface are considered onlink
* @iface: The interface of the next hop
* @ipv6: Switch to only consider IPv6 or IPv4 addresses.
*
* The BSD kernel does not support an onlink flag. If the interface has only
* host addresses configured, all routes should be considered as onlink and
* the function returns 1.
*/
static int
krt_assume_onlink(struct iface *iface, int ipv6)
{
const u8 type = ipv6 ? NET_IP6 : NET_IP4;
struct ifa *ifa;
WALK_LIST(ifa, iface->addrs)
{
if ((ifa->prefix.type == type) && !(ifa->flags & IA_HOST))
return 0;
}
return 1;
}
#define SKIP(ARG...) do { DBG("KRT: Ignoring route - " ARG); return; } while(0)
static void
krt_read_route(struct ks_msg *msg, struct krt_proto *p, int scan)
{
/* p is NULL iff KRT_SHARED_SOCKET and !scan */
int ipv6;
rte *e;
net *net;
sockaddr dst, gate, mask;
ip_addr idst, igate, imask;
net_addr ndst;
void *body = (char *)msg->buf;
int new = (msg->rtm.rtm_type != RTM_DELETE);
char *errmsg = "KRT: Invalid route received";
int flags = msg->rtm.rtm_flags;
int addrs = msg->rtm.rtm_addrs;
int src;
byte src2;
if (!(flags & RTF_UP) && scan)
SKIP("not up in scan\n");
if (!(flags & RTF_DONE) && !scan)
SKIP("not done in async\n");
if (flags & RTF_LLINFO)
SKIP("link-local\n");
GETADDR(&dst, RTA_DST);
GETADDR(&gate, RTA_GATEWAY);
GETADDR(&mask, RTA_NETMASK);
switch (dst.sa.sa_family) {
case AF_INET:
ipv6 = 0;
break;
case AF_INET6:
ipv6 = 1;
break;
default:
SKIP("invalid DST");
}
/* We do not test family for RTA_NETMASK, because BSD sends us
some strange values, but interpreting them as IPv4/IPv6 works */
mask.sa.sa_family = dst.sa.sa_family;
idst = ipa_from_sa(&dst);
imask = ipa_from_sa(&mask);
igate = (gate.sa.sa_family == dst.sa.sa_family) ? ipa_from_sa(&gate) : IPA_NONE;
#ifdef KRT_SHARED_SOCKET
if (!scan)
{
int table_id = msg->rtm.rtm_tableid;
p = (table_id < KRT_MAX_TABLES) ? krt_table_map[table_id][ipv6] : NULL;
if (!p)
SKIP("unknown table id %d\n", table_id);
}
#endif
if ((!ipv6) && (p->p.main_channel->table->addr_type != NET_IP4))
SKIP("reading only IPv4 routes");
if ( ipv6 && (p->p.main_channel->table->addr_type != NET_IP6))
SKIP("reading only IPv6 routes");
int c = ipa_classify_net(idst);
if ((c < 0) || !(c & IADDR_HOST) || ((c & IADDR_SCOPE_MASK) <= SCOPE_LINK))
SKIP("strange class/scope\n");
int pxlen;
if (ipv6)
pxlen = (flags & RTF_HOST) ? IP6_MAX_PREFIX_LENGTH : ip6_masklen(&ipa_to_ip6(imask));
else
pxlen = (flags & RTF_HOST) ? IP4_MAX_PREFIX_LENGTH : ip4_masklen(ipa_to_ip4(imask));
if (pxlen < 0)
{ log(L_ERR "%s (%I) - netmask %I", errmsg, idst, imask); return; }
if (ipv6)
net_fill_ip6(&ndst, ipa_to_ip6(idst), pxlen);
else
net_fill_ip4(&ndst, ipa_to_ip4(idst), pxlen);
if ((flags & RTF_GATEWAY) && ipa_zero(igate))
{ log(L_ERR "%s (%N) - missing gateway", errmsg, &ndst); return; }
u32 self_mask = RTF_PROTO1;
u32 alien_mask = RTF_STATIC | RTF_PROTO1 | RTF_GATEWAY;
src2 = (flags & RTF_STATIC) ? 1 : 0;
src2 |= (flags & RTF_PROTO1) ? 2 : 0;
#ifdef RTF_PROTO2
alien_mask |= RTF_PROTO2;
src2 |= (flags & RTF_PROTO2) ? 4 : 0;
#endif
#ifdef RTF_PROTO3
alien_mask |= RTF_PROTO3;
src2 |= (flags & RTF_PROTO3) ? 8 : 0;
#endif
#ifdef RTF_REJECT
alien_mask |= RTF_REJECT;
#endif
#ifdef RTF_BLACKHOLE
alien_mask |= RTF_BLACKHOLE;
#endif
if (flags & (RTF_DYNAMIC | RTF_MODIFIED))
src = KRT_SRC_REDIRECT;
else if (flags & self_mask)
{
if (!scan)
SKIP("echo\n");
src = KRT_SRC_BIRD;
}
else if (flags & alien_mask)
src = KRT_SRC_ALIEN;
else
src = KRT_SRC_KERNEL;
net = net_get(p->p.main_channel->table, &ndst);
rta a = {
.src = p->p.main_source,
.source = RTS_INHERIT,
.scope = SCOPE_UNIVERSE,
};
/* reject/blackhole routes have also set RTF_GATEWAY,
we wil check them first. */
#ifdef RTF_REJECT
if(flags & RTF_REJECT) {
a.dest = RTD_UNREACHABLE;
goto done;
}
#endif
#ifdef RTF_BLACKHOLE
if(flags & RTF_BLACKHOLE) {
a.dest = RTD_BLACKHOLE;
goto done;
}
#endif
a.nh.iface = if_find_by_index(msg->rtm.rtm_index);
if (!a.nh.iface)
{
log(L_ERR "KRT: Received route %N with unknown ifindex %u",
net->n.addr, msg->rtm.rtm_index);
return;
}
a.dest = RTD_UNICAST;
if (flags & RTF_GATEWAY)
{
a.nh.gw = igate;
/* Clean up embedded interface ID returned in link-local address */
if (ipa_is_link_local(a.nh.gw))
_I0(a.nh.gw) = 0xfe800000;
/* The BSD kernel does not support an onlink flag. We heuristically
set the onlink flag, if the iface has only host addresses. */
if (krt_assume_onlink(a.nh.iface, ipv6))
a.nh.flags |= RNF_ONLINK;
neighbor *nbr;
nbr = neigh_find(&p->p, a.nh.gw, a.nh.iface,
(a.nh.flags & RNF_ONLINK) ? NEF_ONLINK : 0);
if (!nbr || (nbr->scope == SCOPE_HOST))
{
/* Ignore routes with next-hop 127.0.0.1, host routes with such
next-hop appear on OpenBSD for address aliases. */
if (ipa_classify(a.nh.gw) == (IADDR_HOST | SCOPE_HOST))
return;
log(L_ERR "KRT: Received route %N with strange next-hop %I",
net->n.addr, a.nh.gw);
return;
}
}
done:
e = rte_get_temp(&a);
e->net = net;
e->u.krt.src = src;
e->u.krt.proto = src2;
e->u.krt.seen = 0;
e->u.krt.best = 0;
e->u.krt.metric = 0;
if (scan)
krt_got_route(p, e);
else
krt_got_route_async(p, e, new);
}
static void
krt_read_ifannounce(struct ks_msg *msg)
{
struct if_announcemsghdr *ifam = (struct if_announcemsghdr *)&msg->rtm;
if (ifam->ifan_what == IFAN_ARRIVAL)
{
/* Not enough info to create the iface, so we just trigger iface scan */
kif_request_scan();
}
else if (ifam->ifan_what == IFAN_DEPARTURE)
{
struct iface *iface = if_find_by_index(ifam->ifan_index);
/* Interface is destroyed */
if (!iface)
{
DBG("KRT: unknown interface (%s, #%d) going down. Ignoring\n", ifam->ifan_name, ifam->ifan_index);
return;
}
if_delete(iface);
}
DBG("KRT: IFANNOUNCE what: %d index %d name %s\n", ifam->ifan_what, ifam->ifan_index, ifam->ifan_name);
}
static void
krt_read_ifinfo(struct ks_msg *msg, int scan)
{
struct if_msghdr *ifm = (struct if_msghdr *)&msg->rtm;
void *body = (void *)(ifm + 1);
struct sockaddr_dl *dl = NULL;
uint i;
struct iface *iface = NULL, f = {};
int fl = ifm->ifm_flags;
int nlen = 0;
for (i = 1; i<=RTA_IFP; i <<= 1)
{
if (i & ifm->ifm_addrs)
{
if (i == RTA_IFP)
{
dl = (struct sockaddr_dl *)body;
break;
}
body += ROUNDUP(((struct sockaddr *)&(body))->sa_len);
}
}
if (dl && (dl->sdl_family != AF_LINK))
{
log(L_WARN "Ignoring strange IFINFO");
return;
}
if (dl)
nlen = MIN(sizeof(f.name)-1, dl->sdl_nlen);
/* Note that asynchronous IFINFO messages do not contain iface
name, so we have to found an existing iface by iface index */
iface = if_find_by_index(ifm->ifm_index);
if (!iface)
{
/* New interface */
if (!dl)
return; /* No interface name, ignoring */
memcpy(f.name, dl->sdl_data, nlen);
DBG("New interface '%s' found\n", f.name);
}
else if (dl && memcmp(iface->name, dl->sdl_data, nlen))
{
/* Interface renamed */
if_delete(iface);
memcpy(f.name, dl->sdl_data, nlen);
}
else
{
/* Old interface */
memcpy(f.name, iface->name, sizeof(f.name));
}
f.index = ifm->ifm_index;
f.mtu = ifm->ifm_data.ifi_mtu;
if (fl & IFF_UP)
f.flags |= IF_ADMIN_UP;
if (ifm->ifm_data.ifi_link_state != LINK_STATE_DOWN)
f.flags |= IF_LINK_UP; /* up or unknown */
if (fl & IFF_LOOPBACK) /* Loopback */
f.flags |= IF_MULTIACCESS | IF_LOOPBACK | IF_IGNORE;
else if (fl & IFF_POINTOPOINT) /* PtP */
f.flags |= IF_MULTICAST;
else if (fl & IFF_BROADCAST) /* Broadcast */
f.flags |= IF_MULTIACCESS | IF_BROADCAST | IF_MULTICAST;
else
f.flags |= IF_MULTIACCESS; /* NBMA */
if (fl & IFF_MULTICAST)
f.flags |= IF_MULTICAST;
iface = if_update(&f);
if (!scan)
if_end_partial_update(iface);
}
static void
krt_read_addr(struct ks_msg *msg, int scan)
{
struct ifa_msghdr *ifam = (struct ifa_msghdr *)&msg->rtm;
void *body = (void *)(ifam + 1);
sockaddr addr, mask, brd;
struct iface *iface = NULL;
struct ifa ifa;
struct sockaddr null;
ip_addr iaddr, imask, ibrd;
int addrs = ifam->ifam_addrs;
int scope, masklen = -1;
int new = (ifam->ifam_type == RTM_NEWADDR);
/* Strange messages with zero (invalid) ifindex appear on OpenBSD */
if (ifam->ifam_index == 0)
return;
if(!(iface = if_find_by_index(ifam->ifam_index)))
{
log(L_ERR "KIF: Received address message for unknown interface %d", ifam->ifam_index);
return;
}
GETADDR (&null, RTA_DST);
GETADDR (&null, RTA_GATEWAY);
GETADDR (&mask, RTA_NETMASK);
GETADDR (&null, RTA_GENMASK);
GETADDR (&null, RTA_IFP);
GETADDR (&addr, RTA_IFA);
GETADDR (&null, RTA_AUTHOR);
GETADDR (&brd, RTA_BRD);
/* Is addr family IP4 or IP6? */
int ipv6;
switch (addr.sa.sa_family) {
case AF_INET: ipv6 = 0; break;
case AF_INET6: ipv6 = 1; break;
default: return;
}
/* We do not test family for RTA_NETMASK, because BSD sends us
some strange values, but interpreting them as IPv4/IPv6 works */
mask.sa.sa_family = addr.sa.sa_family;
iaddr = ipa_from_sa(&addr);
imask = ipa_from_sa(&mask);
ibrd = ipa_from_sa(&brd);
if ((ipv6 ? (masklen = ip6_masklen(&ipa_to_ip6(imask))) : (masklen = ip4_masklen(ipa_to_ip4(imask)))) < 0)
{
log(L_ERR "KIF: Invalid mask %I for %s", imask, iface->name);
return;
}
/* Clean up embedded interface ID returned in link-local address */
if (ipa_is_link_local(iaddr))
_I0(iaddr) = 0xfe800000;
if (ipa_is_link_local(ibrd))
_I0(ibrd) = 0xfe800000;
bzero(&ifa, sizeof(ifa));
ifa.iface = iface;
ifa.ip = iaddr;
scope = ipa_classify(ifa.ip);
if (scope < 0)
{
log(L_ERR "KIF: Invalid interface address %I for %s", ifa.ip, iface->name);
return;
}
ifa.scope = scope & IADDR_SCOPE_MASK;
if (masklen < (ipv6 ? IP6_MAX_PREFIX_LENGTH : IP4_MAX_PREFIX_LENGTH))
{
net_fill_ipa(&ifa.prefix, ifa.ip, masklen);
net_normalize(&ifa.prefix);
if (masklen == ((ipv6 ? IP6_MAX_PREFIX_LENGTH : IP4_MAX_PREFIX_LENGTH) - 1))
ifa.opposite = ipa_opposite_m1(ifa.ip);
if ((!ipv6) && (masklen == IP4_MAX_PREFIX_LENGTH - 2))
ifa.opposite = ipa_opposite_m2(ifa.ip);
if (iface->flags & IF_BROADCAST)
ifa.brd = ibrd;
if (!(iface->flags & IF_MULTIACCESS))
ifa.opposite = ibrd;
}
else if (!(iface->flags & IF_MULTIACCESS) && ipa_nonzero(ibrd))
{
net_fill_ipa(&ifa.prefix, ibrd, (ipv6 ? IP6_MAX_PREFIX_LENGTH : IP4_MAX_PREFIX_LENGTH));
ifa.opposite = ibrd;
ifa.flags |= IA_PEER;
}
else
{
net_fill_ipa(&ifa.prefix, ifa.ip, (ipv6 ? IP6_MAX_PREFIX_LENGTH : IP4_MAX_PREFIX_LENGTH));
ifa.flags |= IA_HOST;
}
if (new)
ifa_update(&ifa);
else
ifa_delete(&ifa);
if (!scan)
if_end_partial_update(iface);
}
static void
krt_read_msg(struct proto *p, struct ks_msg *msg, int scan)
{
/* p is NULL iff KRT_SHARED_SOCKET and !scan */
switch (msg->rtm.rtm_type)
{
case RTM_GET:
if(!scan) return;
case RTM_ADD:
case RTM_DELETE:
case RTM_CHANGE:
krt_read_route(msg, (struct krt_proto *)p, scan);
break;
case RTM_IFANNOUNCE:
krt_read_ifannounce(msg);
break;
case RTM_IFINFO:
krt_read_ifinfo(msg, scan);
break;
case RTM_NEWADDR:
case RTM_DELADDR:
krt_read_addr(msg, scan);
break;
default:
break;
}
}
/* Sysctl based scans */
static byte *krt_buffer;
static size_t krt_buflen, krt_bufmin;
static struct proto *krt_buffer_owner;
static byte *
krt_buffer_update(struct proto *p, size_t *needed)
{
size_t req = *needed;
if ((req > krt_buflen) ||
((p == krt_buffer_owner) && (req < krt_bufmin)))
{
/* min buflen is 32 kB, step is 8 kB, or 128 kB if > 1 MB */
size_t step = (req < 0x100000) ? 0x2000 : 0x20000;
krt_buflen = (req < 0x6000) ? 0x8000 : (req + step);
krt_bufmin = (req < 0x8000) ? 0 : (req - 2*step);
if (krt_buffer)
mb_free(krt_buffer);
krt_buffer = mb_alloc(krt_pool, krt_buflen);
krt_buffer_owner = p;
}
*needed = krt_buflen;
return krt_buffer;
}
static void
krt_buffer_release(struct proto *p)
{
if (p == krt_buffer_owner)
{
mb_free(krt_buffer);
krt_buffer = NULL;
krt_buflen = 0;
krt_buffer_owner = 0;
}
}
static void
krt_sysctl_scan(struct proto *p, int cmd, int table_id)
{
byte *buf, *next;
int mib[7], mcnt;
size_t needed;
struct ks_msg *m;
int retries = 3;
int rv;
mib[0] = CTL_NET;
mib[1] = PF_ROUTE;
mib[2] = 0;
mib[3] = 0; // Set AF to 0 for all available families
mib[4] = cmd;
mib[5] = 0;
mcnt = 6;
#ifdef KRT_USE_SYSCTL_7
if (table_id >= 0)
{
mib[6] = table_id;
mcnt = 7;
}
#endif
#ifdef KRT_USE_SETFIB_SCAN
if (table_id > 0)
if (setfib(table_id) < 0)
{
log(L_ERR "KRT: setfib(%d) failed: %m", table_id);
return;
}
#endif
try:
rv = sysctl(mib, mcnt, NULL, &needed, NULL, 0);
if (rv < 0)
{
/* OpenBSD returns EINVAL for not yet used tables */
if ((errno == EINVAL) && (table_id > 0))
goto exit;
log(L_ERR "KRT: Route scan estimate failed: %m");
goto exit;
}
/* The table is empty */
if (needed == 0)
goto exit;
buf = krt_buffer_update(p, &needed);
rv = sysctl(mib, mcnt, buf, &needed, NULL, 0);
if (rv < 0)
{
/* The buffer size changed since last sysctl ('needed' is not changed) */
if ((errno == ENOMEM) && retries--)
goto try;
log(L_ERR "KRT: Route scan failed: %m");
goto exit;
}
#ifdef KRT_USE_SETFIB_SCAN
if (table_id > 0)
if (setfib(0) < 0)
die("KRT: setfib(%d) failed: %m", 0);
#endif
/* Process received messages */
for (next = buf; next < (buf + needed); next += m->rtm.rtm_msglen)
{
m = (struct ks_msg *)next;
krt_read_msg(p, m, 1);
}
return;
exit:
krt_buffer_release(p);
#ifdef KRT_USE_SETFIB_SCAN
if (table_id > 0)
if (setfib(0) < 0)
die("KRT: setfib(%d) failed: %m", 0);
#endif
}
void
krt_do_scan(struct krt_proto *p)
{
krt_sysctl_scan(&p->p, NET_RT_DUMP, KRT_CF->sys.table_id);
}
void
kif_do_scan(struct kif_proto *p)
{
if_start_update();
krt_sysctl_scan(&p->p, NET_RT_IFLIST, -1);
if_end_update();
}
/* Kernel sockets */
static int
krt_sock_hook(sock *sk, uint size UNUSED)
{
struct ks_msg msg;
int l = read(sk->fd, (char *)&msg, sizeof(msg));
if (l <= 0)
log(L_ERR "krt-sock: read failed");
else
krt_read_msg((struct proto *) sk->data, &msg, 0);
return 0;
}
static void
krt_sock_err_hook(sock *sk, int e UNUSED)
{
krt_sock_hook(sk, 0);
}
static sock *
krt_sock_open(pool *pool, void *data, int table_id UNUSED)
{
sock *sk;
int fd;
fd = socket(PF_ROUTE, SOCK_RAW, AF_UNSPEC);
if (fd < 0)
die("Cannot open kernel socket for routes");
#ifdef KRT_USE_SETFIB_SOCK
if (table_id > 0)
{
if (setsockopt(fd, SOL_SOCKET, SO_SETFIB, &table_id, sizeof(table_id)) < 0)
die("Cannot set FIB %d for kernel socket: %m", table_id);
}
#endif
sk = sk_new(pool);
sk->type = SK_MAGIC;
sk->rx_hook = krt_sock_hook;
sk->err_hook = krt_sock_err_hook;
sk->fd = fd;
sk->data = data;
if (sk_open(sk) < 0)
bug("krt-sock: sk_open failed");
return sk;
}
static u32 krt_table_cf[(KRT_MAX_TABLES+31) / 32][2];
#ifdef KRT_SHARED_SOCKET
static sock *krt_sock;
static int krt_sock_count;
static void
krt_sock_open_shared(void)
{
if (!krt_sock_count)
krt_sock = krt_sock_open(krt_pool, NULL, -1);
krt_sock_count++;
}
static void
krt_sock_close_shared(void)
{
krt_sock_count--;
if (!krt_sock_count)
{
rfree(krt_sock);
krt_sock = NULL;
}
}
int
krt_sys_start(struct krt_proto *p)
{
int id = KRT_CF->sys.table_id;
if (krt_table_cf[id/32][!!(p->af == AF_INET6)] & (1 << (id%32)))
{
log(L_ERR "%s: Multiple kernel syncers defined for table #%d", p->p.name, id);
return 0;
}
krt_table_cf[id/32][!!(p->af == AF_INET6)] |= (1 << (id%32));
krt_table_map[KRT_CF->sys.table_id][!!(p->af == AF_INET6)] = p;
krt_sock_open_shared();
p->sys.sk = krt_sock;
return 1;
}
void
krt_sys_shutdown(struct krt_proto *p)
{
krt_table_cf[(KRT_CF->sys.table_id)/32][!!(p->af == AF_INET6)] &= ~(1 << ((KRT_CF->sys.table_id)%32));
krt_sock_close_shared();
p->sys.sk = NULL;
krt_table_map[KRT_CF->sys.table_id][!!(p->af == AF_INET6)] = NULL;
krt_buffer_release(&p->p);
}
#else
int
krt_sys_start(struct krt_proto *p)
{
int id = KRT_CF->sys.table_id;
if (krt_table_cf[id/32][!!(p->af == AF_INET6)] & (1 << (id%32)))
{
log(L_ERR "%s: Multiple kernel syncers defined for table #%d", p->p.name, id);
return 0;
}
krt_table_cf[id/32][!!(p->af == AF_INET6)] |= (1 << (id%32));
p->sys.sk = krt_sock_open(p->p.pool, p, KRT_CF->sys.table_id);
return 1;
}
void
krt_sys_shutdown(struct krt_proto *p)
{
krt_table_cf[(KRT_CF->sys.table_id)/32][!!(p->af == AF_INET6)] &= ~(1 << ((KRT_CF->sys.table_id)%32));
rfree(p->sys.sk);
p->sys.sk = NULL;
krt_buffer_release(&p->p);
}
#endif /* KRT_SHARED_SOCKET */
/* KRT configuration callbacks */
int
krt_sys_reconfigure(struct krt_proto *p UNUSED, struct krt_config *n, struct krt_config *o)
{
return n->sys.table_id == o->sys.table_id;
}
void
krt_sys_preconfig(struct config *c UNUSED)
{
krt_max_tables = krt_get_max_tables();
bzero(&krt_table_cf, sizeof(krt_table_cf));
}
void krt_sys_init_config(struct krt_config *c)
{
c->sys.table_id = 0; /* Default table */
}
void krt_sys_copy_config(struct krt_config *d, struct krt_config *s)
{
d->sys.table_id = s->sys.table_id;
}
/* KIF misc code */
void
kif_sys_start(struct kif_proto *p UNUSED)
{
}
void
kif_sys_shutdown(struct kif_proto *p)
{
krt_buffer_release(&p->p);
}
int
kif_update_sysdep_addr(struct iface *i)
{
static int fd = -1;
if (fd < 0)
fd = socket(AF_INET, SOCK_DGRAM, 0);
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, i->name, IFNAMSIZ);
int rv = ioctl(fd, SIOCGIFADDR, (char *) &ifr);
if (rv < 0)
return 0;
ip4_addr old = i->sysdep;
i->sysdep = ipa_to_ip4(ipa_from_sa4(&ifr.ifr_addr));
return !ip4_equal(i->sysdep, old);
}
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