bird/sysdep/bsd/krt-sock.c
2013-07-04 18:02:22 +02:00

759 lines
16 KiB
C

/*
* BIRD -- Unix 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 <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 "lib/timer.h"
#include "lib/unix.h"
#include "lib/krt.h"
#include "lib/string.h"
#include "lib/socket.h"
#ifndef RTAX_MAX
#define RTAX_MAX 8
#endif
struct ks_msg
{
struct rt_msghdr rtm;
struct sockaddr_storage buf[RTAX_MAX];
};
static int rt_sock = 0;
int
krt_capable(rte *e)
{
rta *a = e->attrs;
return
a->cast == RTC_UNICAST &&
(a->dest == RTD_ROUTER
|| a->dest == RTD_DEVICE
#ifdef RTF_REJECT
|| a->dest == RTD_UNREACHABLE
#endif
#ifdef RTF_BLACKHOLE
|| a->dest == RTD_BLACKHOLE
#endif
);
}
#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) {\
unsigned int l = ROUNDUP(((struct sockaddr *)body)->sa_len);\
memcpy(p, body, (l > sizeof(*p) ? sizeof(*p) : l));\
body += l;}
static int
krt_sock_send(int cmd, rte *e)
{
net *net = e->net;
rta *a = e->attrs;
static int msg_seq;
struct iface *j, *i = a->iface;
int l;
struct ks_msg msg;
char *body = (char *)msg.buf;
sockaddr gate, mask, dst;
ip_addr gw;
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;
if (net->n.pxlen == MAX_PREFIX_LENGTH)
{
msg.rtm.rtm_flags |= RTF_HOST;
}
else
{
msg.rtm.rtm_addrs |= RTA_NETMASK;
}
#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 set
*/
if(!i)
{
i = HEAD(iface_list);
WALK_LIST(j, iface_list)
{
if (j->flags & IF_LOOPBACK)
{
i = j;
break;
}
}
}
gw = a->gw;
#ifdef IPV6
/* Embed interface ID to link-local address */
if (ipa_has_link_scope(gw))
_I0(gw) = 0xfe800000 | (i->index & 0x0000ffff);
#endif
fill_in_sockaddr(&dst, net->n.prefix, NULL, 0);
fill_in_sockaddr(&mask, ipa_mkmask(net->n.pxlen), NULL, 0);
fill_in_sockaddr(&gate, gw, NULL, 0);
switch (a->dest)
{
case RTD_ROUTER:
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
case RTD_DEVICE:
if(i)
{
#ifdef RTF_CLONING
if (cmd == RTM_ADD && (i->flags & IF_MULTIACCESS) != IF_MULTIACCESS) /* PTP */
msg.rtm.rtm_flags |= RTF_CLONING;
#endif
if(!i->addr) {
log(L_ERR "KRT: interface %s has no IP addess", i->name);
return -1;
}
fill_in_sockaddr(&gate, i->addr->ip, NULL, 0);
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(rt_sock, (char *)&msg, l)) < 0) {
log(L_ERR "KRT: Error sending route %I/%d to kernel: %m", net->n.prefix, net->n.pxlen);
return -1;
}
return 0;
}
void
krt_replace_rte(struct krt_proto *p UNUSED, net *n, rte *new, rte *old,
struct ea_list *eattrs UNUSED)
{
int err = 0;
if (old)
krt_sock_send(RTM_DELETE, old);
if (new)
err = krt_sock_send(RTM_ADD, new);
if (err < 0)
n->n.flags |= KRF_SYNC_ERROR;
else
n->n.flags &= ~KRF_SYNC_ERROR;
}
#define SKIP(ARG...) do { DBG("KRT: Ignoring route - " ARG); return; } while(0)
static void
krt_read_rt(struct ks_msg *msg, struct krt_proto *p, int scan)
{
rte *e;
net *net;
sockaddr dst, gate, mask;
ip_addr idst, igate, imask;
void *body = (char *)msg->buf;
int new = (msg->rtm.rtm_type == RTM_ADD);
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);
if (sa_family_check(&dst))
get_sockaddr(&dst, &idst, NULL, NULL, 0);
else
SKIP("invalid DST");
/* We will check later whether we have valid gateway addr */
if (sa_family_check(&gate))
get_sockaddr(&gate, &igate, NULL, NULL, 0);
else
igate = IPA_NONE;
/* We do not test family for RTA_NETMASK, because BSD sends us
some strange values, but interpreting them as IPv4/IPv6 works */
get_sockaddr(&mask, &imask, NULL, NULL, 0);
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 = (flags & RTF_HOST) ? MAX_PREFIX_LENGTH : ipa_mklen(imask);
if (pxlen < 0)
{ log(L_ERR "%s (%I) - netmask %I", errmsg, idst, imask); return; }
if ((flags & RTF_GATEWAY) && ipa_zero(igate))
{ log(L_ERR "%s (%I/%d) - missing gateway", errmsg, idst, pxlen); 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.table, idst, pxlen);
rta a = {
.proto = &p->p,
.source = RTS_INHERIT,
.scope = SCOPE_UNIVERSE,
.cast = RTC_UNICAST
};
/* 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.iface = if_find_by_index(msg->rtm.rtm_index);
if (!a.iface)
{
log(L_ERR "KRT: Received route %I/%d with unknown ifindex %u",
net->n.prefix, net->n.pxlen, msg->rtm.rtm_index);
return;
}
if (flags & RTF_GATEWAY)
{
neighbor *ng;
a.dest = RTD_ROUTER;
a.gw = igate;
#ifdef IPV6
/* Clean up embedded interface ID returned in link-local address */
if (ipa_has_link_scope(a.gw))
_I0(a.gw) = 0xfe800000;
#endif
ng = neigh_find2(&p->p, &a.gw, a.iface, 0);
if (!ng || (ng->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.gw) == (IADDR_HOST | SCOPE_HOST))
return;
log(L_ERR "KRT: Received route %I/%d with strange next-hop %I",
net->n.prefix, net->n.pxlen, a.gw);
return;
}
}
else
a.dest = RTD_DEVICE;
done:
e = rte_get_temp(&a);
e->net = net;
e->u.krt.src = src;
e->u.krt.proto = src2;
/* These are probably too Linux-specific */
e->u.krt.type = 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)
{
struct if_msghdr *ifm = (struct if_msghdr *)&msg->rtm;
void *body = (void *)(ifm + 1);
struct sockaddr_dl *dl = NULL;
unsigned int 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_update(&f);
}
static void
krt_read_addr(struct ks_msg *msg)
{
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);
/* Some other family address */
if (!sa_family_check(&addr))
return;
get_sockaddr(&addr, &iaddr, NULL, NULL, 0);
get_sockaddr(&mask, &imask, NULL, NULL, 0);
get_sockaddr(&brd, &ibrd, NULL, NULL, 0);
if ((masklen = ipa_mklen(imask)) < 0)
{
log("Invalid masklen");
return;
}
bzero(&ifa, sizeof(ifa));
ifa.iface = iface;
memcpy(&ifa.ip, &iaddr, sizeof(ip_addr));
ifa.pxlen = masklen;
memcpy(&ifa.brd, &ibrd, sizeof(ip_addr));
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;
#ifdef IPV6
/* Clean up embedded interface ID returned in link-local address */
if (ipa_has_link_scope(ifa.ip))
_I0(ifa.ip) = 0xfe800000;
#endif
#ifdef IPV6
/* Why not the same check also for IPv4? */
if ((iface->flags & IF_MULTIACCESS) || (masklen != BITS_PER_IP_ADDRESS))
#else
if (iface->flags & IF_MULTIACCESS)
#endif
{
ifa.prefix = ipa_and(ifa.ip, ipa_mkmask(masklen));
if (masklen == BITS_PER_IP_ADDRESS)
ifa.flags |= IA_HOST;
if (masklen == (BITS_PER_IP_ADDRESS - 1))
ifa.opposite = ipa_opposite_m1(ifa.ip);
#ifndef IPV6
if (masklen == (BITS_PER_IP_ADDRESS - 2))
ifa.opposite = ipa_opposite_m2(ifa.ip);
#endif
}
else /* PtP iface */
{
ifa.flags |= IA_PEER;
ifa.prefix = ifa.opposite = ifa.brd;
}
if (new)
ifa_update(&ifa);
else
ifa_delete(&ifa);
}
void
krt_read_msg(struct proto *p, struct ks_msg *msg, int scan)
{
switch (msg->rtm.rtm_type)
{
case RTM_GET:
if(!scan) return;
case RTM_ADD:
case RTM_DELETE:
krt_read_rt(msg, (struct krt_proto *)p, scan);
break;
case RTM_IFANNOUNCE:
krt_read_ifannounce(msg);
break;
case RTM_IFINFO:
krt_read_ifinfo(msg);
break;
case RTM_NEWADDR:
case RTM_DELADDR:
krt_read_addr(msg);
break;
default:
break;
}
}
static void
krt_sysctl_scan(struct proto *p, pool *pool, byte **buf, size_t *bl, int cmd)
{
byte *next;
int mib[6];
size_t obl, needed;
struct ks_msg *m;
int retries = 3;
mib[0] = CTL_NET;
mib[1] = PF_ROUTE;
mib[2] = 0;
mib[3] = BIRD_PF;
mib[4] = cmd;
mib[5] = 0;
try:
if (sysctl(mib, 6 , NULL , &needed, NULL, 0) < 0)
die("krt_sysctl_scan 1: %m");
obl = *bl;
while (needed > *bl) *bl *= 2;
while (needed < (*bl/2)) *bl /= 2;
if ((obl!=*bl) || !*buf)
{
if (*buf) mb_free(*buf);
if ((*buf = mb_alloc(pool, *bl)) == NULL) die("RT scan buf alloc");
}
if (sysctl(mib, 6 , *buf, &needed, NULL, 0) < 0)
{
if (errno == ENOMEM)
{
/* The buffer size changed since last sysctl ('needed' is not changed) */
if (retries--)
goto try;
log(L_ERR "KRT: Route scan failed");
return;
}
die("krt_sysctl_scan 2: %m");
}
for (next = *buf; next < (*buf + needed); next += m->rtm.rtm_msglen)
{
m = (struct ks_msg *)next;
krt_read_msg(p, m, 1);
}
}
static byte *krt_buffer = NULL;
static byte *kif_buffer = NULL;
static size_t krt_buflen = 32768;
static size_t kif_buflen = 4096;
void
krt_do_scan(struct krt_proto *p)
{
krt_sysctl_scan(&p->p, p->p.pool, &krt_buffer, &krt_buflen, NET_RT_DUMP);
}
void
kif_do_scan(struct kif_proto *p)
{
if_start_update();
krt_sysctl_scan(&p->p, p->p.pool, &kif_buffer, &kif_buflen, NET_RT_IFLIST);
if_end_update();
}
static int
krt_sock_hook(sock *sk, int 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;
}
void
krt_sys_start(struct krt_proto *x)
{
sock *sk_rt;
static int ks_open_tried = 0;
if (ks_open_tried)
return;
ks_open_tried = 1;
DBG("KRT: Opening kernel socket\n");
if( (rt_sock = socket(PF_ROUTE, SOCK_RAW, AF_UNSPEC)) < 0)
die("Cannot open kernel socket for routes");
sk_rt = sk_new(krt_pool);
sk_rt->type = SK_MAGIC;
sk_rt->rx_hook = krt_sock_hook;
sk_rt->fd = rt_sock;
sk_rt->data = x;
if (sk_open(sk_rt))
bug("krt-sock: sk_open failed");
}
void
krt_sys_shutdown(struct krt_proto *x UNUSED)
{
if (!krt_buffer)
return;
mb_free(krt_buffer);
krt_buffer = NULL;
}
void
kif_sys_start(struct kif_proto *p UNUSED)
{
}
void
kif_sys_shutdown(struct kif_proto *p UNUSED)
{
if (!kif_buffer)
return;
mb_free(kif_buffer);
kif_buffer = NULL;
}