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labs-bird/sysdep/linux/netlink/netlink.c
Ondrej Zajicek 32b4972834 Multipath support for linux kernel protocol.
2010-12-07 23:36:11 +01:00

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/*
* BIRD -- Linux Netlink Interface
*
* (c) 1999--2000 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include <stdio.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <errno.h>
#undef LOCAL_DEBUG
#include "nest/bird.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/socket.h"
#include "lib/string.h"
#include "conf/conf.h"
#include <asm/types.h>
#include <linux/if.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#ifndef MSG_TRUNC /* Hack: Several versions of glibc miss this one :( */
#define MSG_TRUNC 0x20
#endif
#ifndef IFF_LOWER_UP
#define IFF_LOWER_UP 0x10000
#endif
/*
* Synchronous Netlink interface
*/
struct nl_sock
{
int fd;
u32 seq;
byte *rx_buffer; /* Receive buffer */
struct nlmsghdr *last_hdr; /* Recently received packet */
unsigned int last_size;
};
#define NL_RX_SIZE 8192
static struct nl_sock nl_scan = {.fd = -1}; /* Netlink socket for synchronous scan */
static struct nl_sock nl_req = {.fd = -1}; /* Netlink socket for requests */
static void
nl_open_sock(struct nl_sock *nl)
{
if (nl->fd < 0)
{
nl->fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (nl->fd < 0)
die("Unable to open rtnetlink socket: %m");
nl->seq = now;
nl->rx_buffer = xmalloc(NL_RX_SIZE);
nl->last_hdr = NULL;
nl->last_size = 0;
}
}
static void
nl_open(void)
{
nl_open_sock(&nl_scan);
nl_open_sock(&nl_req);
}
static void
nl_send(struct nl_sock *nl, struct nlmsghdr *nh)
{
struct sockaddr_nl sa;
memset(&sa, 0, sizeof(sa));
sa.nl_family = AF_NETLINK;
nh->nlmsg_pid = 0;
nh->nlmsg_seq = ++(nl->seq);
if (sendto(nl->fd, nh, nh->nlmsg_len, 0, (struct sockaddr *)&sa, sizeof(sa)) < 0)
die("rtnetlink sendto: %m");
nl->last_hdr = NULL;
}
static void
nl_request_dump(int cmd)
{
struct {
struct nlmsghdr nh;
struct rtgenmsg g;
} req;
req.nh.nlmsg_type = cmd;
req.nh.nlmsg_len = sizeof(req);
req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
/* Is it important which PF_* is used for link-level interface scan?
It seems that some information is available only when PF_INET is used. */
req.g.rtgen_family = (cmd == RTM_GETLINK) ? PF_INET : BIRD_PF;
nl_send(&nl_scan, &req.nh);
}
static struct nlmsghdr *
nl_get_reply(struct nl_sock *nl)
{
for(;;)
{
if (!nl->last_hdr)
{
struct iovec iov = { nl->rx_buffer, NL_RX_SIZE };
struct sockaddr_nl sa;
struct msghdr m = { (struct sockaddr *) &sa, sizeof(sa), &iov, 1, NULL, 0, 0 };
int x = recvmsg(nl->fd, &m, 0);
if (x < 0)
die("nl_get_reply: %m");
if (sa.nl_pid) /* It isn't from the kernel */
{
DBG("Non-kernel packet\n");
continue;
}
nl->last_size = x;
nl->last_hdr = (void *) nl->rx_buffer;
if (m.msg_flags & MSG_TRUNC)
bug("nl_get_reply: got truncated reply which should be impossible");
}
if (NLMSG_OK(nl->last_hdr, nl->last_size))
{
struct nlmsghdr *h = nl->last_hdr;
nl->last_hdr = NLMSG_NEXT(h, nl->last_size);
if (h->nlmsg_seq != nl->seq)
{
log(L_WARN "nl_get_reply: Ignoring out of sequence netlink packet (%x != %x)",
h->nlmsg_seq, nl->seq);
continue;
}
return h;
}
if (nl->last_size)
log(L_WARN "nl_get_reply: Found packet remnant of size %d", nl->last_size);
nl->last_hdr = NULL;
}
}
static struct rate_limit rl_netlink_err;
static int
nl_error(struct nlmsghdr *h)
{
struct nlmsgerr *e;
int ec;
if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr)))
{
log(L_WARN "Netlink: Truncated error message received");
return ENOBUFS;
}
e = (struct nlmsgerr *) NLMSG_DATA(h);
ec = -e->error;
if (ec)
log_rl(&rl_netlink_err, L_WARN "Netlink: %s", strerror(ec));
return ec;
}
static struct nlmsghdr *
nl_get_scan(void)
{
struct nlmsghdr *h = nl_get_reply(&nl_scan);
if (h->nlmsg_type == NLMSG_DONE)
return NULL;
if (h->nlmsg_type == NLMSG_ERROR)
{
nl_error(h);
return NULL;
}
return h;
}
static int
nl_exchange(struct nlmsghdr *pkt)
{
struct nlmsghdr *h;
nl_send(&nl_req, pkt);
for(;;)
{
h = nl_get_reply(&nl_req);
if (h->nlmsg_type == NLMSG_ERROR)
break;
log(L_WARN "nl_exchange: Unexpected reply received");
}
return nl_error(h);
}
/*
* Netlink attributes
*/
static int nl_attr_len;
static void *
nl_checkin(struct nlmsghdr *h, int lsize)
{
nl_attr_len = h->nlmsg_len - NLMSG_LENGTH(lsize);
if (nl_attr_len < 0)
{
log(L_ERR "nl_checkin: underrun by %d bytes", -nl_attr_len);
return NULL;
}
return NLMSG_DATA(h);
}
static int
nl_parse_attrs(struct rtattr *a, struct rtattr **k, int ksize)
{
int max = ksize / sizeof(struct rtattr *);
bzero(k, ksize);
while (RTA_OK(a, nl_attr_len))
{
if (a->rta_type < max)
k[a->rta_type] = a;
a = RTA_NEXT(a, nl_attr_len);
}
if (nl_attr_len)
{
log(L_ERR "nl_parse_attrs: remnant of size %d", nl_attr_len);
return 0;
}
else
return 1;
}
void
nl_add_attr(struct nlmsghdr *h, unsigned bufsize, unsigned code,
void *data, unsigned dlen)
{
unsigned len = RTA_LENGTH(dlen);
unsigned pos = NLMSG_ALIGN(h->nlmsg_len);
struct rtattr *a;
if (pos + len > bufsize)
bug("nl_add_attr: packet buffer overflow");
a = (struct rtattr *)((char *)h + pos);
a->rta_type = code;
a->rta_len = len;
h->nlmsg_len = pos + len;
memcpy(RTA_DATA(a), data, dlen);
}
static inline void
nl_add_attr_u32(struct nlmsghdr *h, unsigned bufsize, int code, u32 data)
{
nl_add_attr(h, bufsize, code, &data, 4);
}
static inline void
nl_add_attr_ipa(struct nlmsghdr *h, unsigned bufsize, int code, ip_addr ipa)
{
ipa_hton(ipa);
nl_add_attr(h, bufsize, code, &ipa, sizeof(ipa));
}
#define RTNH_SIZE (sizeof(struct rtnexthop) + sizeof(struct rtattr) + sizeof(ip_addr))
static inline void
add_mpnexthop(char *buf, ip_addr ipa, unsigned iface, unsigned char weight)
{
struct rtnexthop *nh = (void *) buf;
struct rtattr *rt = (void *) (buf + sizeof(*nh));
nh->rtnh_len = RTNH_SIZE;
nh->rtnh_flags = 0;
nh->rtnh_hops = weight;
nh->rtnh_ifindex = iface;
rt->rta_len = sizeof(*rt) + sizeof(ipa);
rt->rta_type = RTA_GATEWAY;
ipa_hton(ipa);
memcpy(buf + sizeof(*nh) + sizeof(*rt), &ipa, sizeof(ipa));
}
static void
nl_add_multipath(struct nlmsghdr *h, unsigned bufsize, struct mpnh *nh)
{
unsigned len = sizeof(struct rtattr);
unsigned pos = NLMSG_ALIGN(h->nlmsg_len);
char *buf = (char *)h + pos;
struct rtattr *rt = (void *) buf;
buf += len;
for (; nh; nh = nh->next)
{
len += RTNH_SIZE;
if (pos + len > bufsize)
bug("nl_add_multipath: packet buffer overflow");
add_mpnexthop(buf, nh->gw, nh->iface->index, nh->weight);
buf += RTNH_SIZE;
}
rt->rta_type = RTA_MULTIPATH;
rt->rta_len = len;
h->nlmsg_len = pos + len;
}
static struct mpnh *
nl_parse_multipath(struct krt_proto *p, struct rtattr *ra)
{
/* Temporary buffer for multicast nexthops */
static struct mpnh *nh_buffer;
static int nh_buf_size; /* in number of structures */
static int nh_buf_used;
struct rtattr *a[RTA_CACHEINFO+1];
struct rtnexthop *nh = RTA_DATA(ra);
struct mpnh *rv, *first, **last;
int len = RTA_PAYLOAD(ra);
first = NULL;
last = &first;
nh_buf_used = 0;
while (len)
{
/* Use RTNH_OK(nh,len) ?? */
if ((len < sizeof(*nh)) || (len < nh->rtnh_len))
return NULL;
if (nh_buf_used == nh_buf_size)
{
nh_buf_size = nh_buf_size ? (nh_buf_size * 2) : 4;
nh_buffer = xrealloc(nh_buffer, nh_buf_size * sizeof(struct mpnh));
}
*last = rv = nh_buffer + nh_buf_used++;
rv->next = NULL;
last = &(rv->next);
rv->weight = nh->rtnh_hops;
rv->iface = if_find_by_index(nh->rtnh_ifindex);
if (!rv->iface)
return NULL;
/* Nonexistent RTNH_PAYLOAD ?? */
nl_attr_len = nh->rtnh_len - RTNH_LENGTH(0);
nl_parse_attrs(RTNH_DATA(nh), a, sizeof(a));
if (a[RTA_GATEWAY])
{
if (RTA_PAYLOAD(a[RTA_GATEWAY]) != sizeof(ip_addr))
return NULL;
memcpy(&rv->gw, RTA_DATA(a[RTA_GATEWAY]), sizeof(ip_addr));
ipa_ntoh(rv->gw);
neighbor *ng = neigh_find2(&p->p, &rv->gw, rv->iface,
(nh->rtnh_flags & RTNH_F_ONLINK) ? NEF_ONLINK : 0);
if (!ng || (ng->scope == SCOPE_HOST))
return NULL;
}
else
return NULL;
len -= NLMSG_ALIGN(nh->rtnh_len);
nh = RTNH_NEXT(nh);
}
return first;
}
/*
* Scanning of interfaces
*/
static void
nl_parse_link(struct nlmsghdr *h, int scan)
{
struct ifinfomsg *i;
struct rtattr *a[IFLA_WIRELESS+1];
int new = h->nlmsg_type == RTM_NEWLINK;
struct iface f;
struct iface *ifi;
char *name;
u32 mtu;
unsigned int fl;
if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFLA_RTA(i), a, sizeof(a)))
return;
if (!a[IFLA_IFNAME] || RTA_PAYLOAD(a[IFLA_IFNAME]) < 2 ||
!a[IFLA_MTU] || RTA_PAYLOAD(a[IFLA_MTU]) != 4)
{
if (scan || !a[IFLA_WIRELESS])
log(L_ERR "nl_parse_link: Malformed message received");
return;
}
name = RTA_DATA(a[IFLA_IFNAME]);
memcpy(&mtu, RTA_DATA(a[IFLA_MTU]), sizeof(u32));
ifi = if_find_by_index(i->ifi_index);
if (!new)
{
DBG("KIF: IF%d(%s) goes down\n", i->ifi_index, name);
if (ifi && !scan)
{
memcpy(&f, ifi, sizeof(struct iface));
f.flags |= IF_SHUTDOWN;
if_update(&f);
}
}
else
{
DBG("KIF: IF%d(%s) goes up (mtu=%d,flg=%x)\n", i->ifi_index, name, mtu, i->ifi_flags);
if (ifi)
memcpy(&f, ifi, sizeof(f));
else
{
bzero(&f, sizeof(f));
f.index = i->ifi_index;
}
strncpy(f.name, RTA_DATA(a[IFLA_IFNAME]), sizeof(f.name)-1);
f.mtu = mtu;
f.flags = 0;
fl = i->ifi_flags;
if (fl & IFF_UP)
f.flags |= IF_ADMIN_UP;
if (fl & IFF_LOWER_UP)
f.flags |= IF_LINK_UP;
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
nl_parse_addr(struct nlmsghdr *h)
{
struct ifaddrmsg *i;
struct rtattr *a[IFA_ANYCAST+1];
int new = h->nlmsg_type == RTM_NEWADDR;
struct ifa ifa;
struct iface *ifi;
int scope;
if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFA_RTA(i), a, sizeof(a)))
return;
if (i->ifa_family != BIRD_AF)
return;
if (!a[IFA_ADDRESS] || RTA_PAYLOAD(a[IFA_ADDRESS]) != sizeof(ip_addr)
#ifdef IPV6
|| a[IFA_LOCAL] && RTA_PAYLOAD(a[IFA_LOCAL]) != sizeof(ip_addr)
#else
|| !a[IFA_LOCAL] || RTA_PAYLOAD(a[IFA_LOCAL]) != sizeof(ip_addr)
|| (a[IFA_BROADCAST] && RTA_PAYLOAD(a[IFA_BROADCAST]) != sizeof(ip_addr))
#endif
)
{
log(L_ERR "nl_parse_addr: Malformed message received");
return;
}
ifi = if_find_by_index(i->ifa_index);
if (!ifi)
{
log(L_ERR "KIF: Received address message for unknown interface %d", i->ifa_index);
return;
}
bzero(&ifa, sizeof(ifa));
ifa.iface = ifi;
if (i->ifa_flags & IFA_F_SECONDARY)
ifa.flags |= IA_SECONDARY;
/* IFA_LOCAL can be unset for IPv6 interfaces */
memcpy(&ifa.ip, RTA_DATA(a[IFA_LOCAL] ? : a[IFA_ADDRESS]), sizeof(ifa.ip));
ipa_ntoh(ifa.ip);
ifa.pxlen = i->ifa_prefixlen;
if (i->ifa_prefixlen > BITS_PER_IP_ADDRESS)
{
log(L_ERR "KIF: Invalid prefix length for interface %s: %d", ifi->name, i->ifa_prefixlen);
new = 0;
}
if (i->ifa_prefixlen == BITS_PER_IP_ADDRESS)
{
ip_addr addr;
memcpy(&addr, RTA_DATA(a[IFA_ADDRESS]), sizeof(addr));
ipa_ntoh(addr);
ifa.prefix = ifa.brd = addr;
/* It is either a peer address, or loopback/dummy address */
if (!ipa_equal(ifa.ip, addr))
{
ifa.flags |= IA_UNNUMBERED;
ifa.opposite = addr;
}
}
else
{
ip_addr netmask = ipa_mkmask(ifa.pxlen);
ifa.prefix = ipa_and(ifa.ip, netmask);
ifa.brd = ipa_or(ifa.ip, ipa_not(netmask));
if (i->ifa_prefixlen == BITS_PER_IP_ADDRESS - 1)
ifa.opposite = ipa_opposite_m1(ifa.ip);
#ifndef IPV6
if (i->ifa_prefixlen == BITS_PER_IP_ADDRESS - 2)
ifa.opposite = ipa_opposite_m2(ifa.ip);
if ((ifi->flags & IF_BROADCAST) && a[IFA_BROADCAST])
{
ip_addr xbrd;
memcpy(&xbrd, RTA_DATA(a[IFA_BROADCAST]), sizeof(xbrd));
ipa_ntoh(xbrd);
if (ipa_equal(xbrd, ifa.prefix) || ipa_equal(xbrd, ifa.brd))
ifa.brd = xbrd;
else if (ifi->flags & IF_TMP_DOWN) /* Complain only during the first scan */
log(L_ERR "KIF: Invalid broadcast address %I for %s", xbrd, ifi->name);
}
#endif
}
scope = ipa_classify(ifa.ip);
if (scope < 0)
{
log(L_ERR "KIF: Invalid interface address %I for %s", ifa.ip, ifi->name);
return;
}
ifa.scope = scope & IADDR_SCOPE_MASK;
DBG("KIF: IF%d(%s): %s IPA %I, flg %x, net %I/%d, brd %I, opp %I\n",
ifi->index, ifi->name,
new ? "added" : "removed",
ifa.ip, ifa.flags, ifa.prefix, ifa.pxlen, ifa.brd, ifa.opposite);
if (new)
ifa_update(&ifa);
else
ifa_delete(&ifa);
}
void
krt_if_scan(struct kif_proto *p UNUSED)
{
struct nlmsghdr *h;
if_start_update();
nl_request_dump(RTM_GETLINK);
while (h = nl_get_scan())
if (h->nlmsg_type == RTM_NEWLINK || h->nlmsg_type == RTM_DELLINK)
nl_parse_link(h, 1);
else
log(L_DEBUG "nl_scan_ifaces: Unknown packet received (type=%d)", h->nlmsg_type);
nl_request_dump(RTM_GETADDR);
while (h = nl_get_scan())
if (h->nlmsg_type == RTM_NEWADDR || h->nlmsg_type == RTM_DELADDR)
nl_parse_addr(h);
else
log(L_DEBUG "nl_scan_ifaces: Unknown packet received (type=%d)", h->nlmsg_type);
if_end_update();
}
/*
* Routes
*/
static struct krt_proto *nl_table_map[NL_NUM_TABLES];
int
krt_capable(rte *e)
{
rta *a = e->attrs;
if (a->cast != RTC_UNICAST)
return 0;
switch (a->dest)
{
case RTD_ROUTER:
if (ipa_has_link_scope(a->gw) && (a->iface == NULL))
return 0;
case RTD_DEVICE:
case RTD_BLACKHOLE:
case RTD_UNREACHABLE:
case RTD_PROHIBIT:
case RTD_MULTIPATH:
break;
default:
return 0;
}
return 1;
}
static inline int
nh_bufsize(struct mpnh *nh)
{
int rv = 0;
for (; nh != NULL; nh = nh->next)
rv += RTNH_SIZE;
return rv;
}
static void
nl_send_route(struct krt_proto *p, rte *e, int new)
{
net *net = e->net;
rta *a = e->attrs;
struct {
struct nlmsghdr h;
struct rtmsg r;
char buf[64 + nh_bufsize(a->nexthops)];
} r;
DBG("nl_send_route(%I/%d,new=%d)\n", net->n.prefix, net->n.pxlen, new);
bzero(&r.h, sizeof(r.h));
bzero(&r.r, sizeof(r.r));
r.h.nlmsg_type = new ? RTM_NEWROUTE : RTM_DELROUTE;
r.h.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
r.h.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | (new ? NLM_F_CREATE|NLM_F_EXCL : 0);
r.r.rtm_family = BIRD_AF;
r.r.rtm_dst_len = net->n.pxlen;
r.r.rtm_tos = 0;
r.r.rtm_table = KRT_CF->scan.table_id;
r.r.rtm_protocol = RTPROT_BIRD;
r.r.rtm_scope = RT_SCOPE_UNIVERSE;
nl_add_attr_ipa(&r.h, sizeof(r), RTA_DST, net->n.prefix);
switch (a->dest)
{
case RTD_ROUTER:
r.r.rtm_type = RTN_UNICAST;
nl_add_attr_ipa(&r.h, sizeof(r), RTA_GATEWAY, a->gw);
/* a->iface != NULL checked in krt_capable() */
if (ipa_has_link_scope(a->gw))
nl_add_attr_u32(&r.h, sizeof(r), RTA_OIF, a->iface->index);
break;
case RTD_DEVICE:
if (!a->iface)
return;
r.r.rtm_type = RTN_UNICAST;
nl_add_attr_u32(&r.h, sizeof(r), RTA_OIF, a->iface->index);
break;
case RTD_BLACKHOLE:
r.r.rtm_type = RTN_BLACKHOLE;
break;
case RTD_UNREACHABLE:
r.r.rtm_type = RTN_UNREACHABLE;
break;
case RTD_PROHIBIT:
r.r.rtm_type = RTN_PROHIBIT;
break;
case RTD_MULTIPATH:
r.r.rtm_type = RTN_UNICAST;
nl_add_multipath(&r.h, sizeof(r), a->nexthops);
break;
default:
bug("krt_capable inconsistent with nl_send_route");
}
nl_exchange(&r.h);
}
void
krt_set_notify(struct krt_proto *p, net *n UNUSED, rte *new, rte *old)
{
if (old)
nl_send_route(p, old, 0);
if (new)
nl_send_route(p, new, 1);
}
#define SKIP(ARG...) do { DBG("KRT: Ignoring route - " ARG); return; } while(0)
static void
nl_parse_route(struct nlmsghdr *h, int scan)
{
struct krt_proto *p;
struct rtmsg *i;
struct rtattr *a[RTA_CACHEINFO+1];
int new = h->nlmsg_type == RTM_NEWROUTE;
ip_addr dst;
rte *e;
net *net;
u32 oif;
int src;
if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(RTM_RTA(i), a, sizeof(a)))
return;
if (i->rtm_family != BIRD_AF)
return;
if ((a[RTA_DST] && RTA_PAYLOAD(a[RTA_DST]) != sizeof(ip_addr)) ||
(a[RTA_OIF] && RTA_PAYLOAD(a[RTA_OIF]) != 4) ||
(a[RTA_PRIORITY] && RTA_PAYLOAD(a[RTA_PRIORITY]) != 4) ||
#ifdef IPV6
(a[RTA_IIF] && RTA_PAYLOAD(a[RTA_IIF]) != 4) ||
#endif
(a[RTA_GATEWAY] && RTA_PAYLOAD(a[RTA_GATEWAY]) != sizeof(ip_addr)))
{
log(L_ERR "KRT: Malformed message received");
return;
}
if (a[RTA_DST])
{
memcpy(&dst, RTA_DATA(a[RTA_DST]), sizeof(dst));
ipa_ntoh(dst);
}
else
dst = IPA_NONE;
if (a[RTA_OIF])
memcpy(&oif, RTA_DATA(a[RTA_OIF]), sizeof(oif));
else
oif = ~0;
DBG("KRT: Got %I/%d, type=%d, oif=%d, table=%d, prid=%d, proto=%s\n", dst, i->rtm_dst_len, i->rtm_type, oif, i->rtm_table, i->rtm_protocol, p->p.name);
p = nl_table_map[i->rtm_table]; /* Do we know this table? */
if (!p)
SKIP("unknown table %d", i->rtm_table);
#ifdef IPV6
if (a[RTA_IIF])
SKIP("IIF set\n");
#else
if (i->rtm_tos != 0) /* We don't support TOS */
SKIP("TOS %02x\n", i->rtm_tos);
#endif
if (scan && !new)
SKIP("RTM_DELROUTE in scan\n");
int c = ipa_classify_net(dst);
if ((c < 0) || !(c & IADDR_HOST) || ((c & IADDR_SCOPE_MASK) <= SCOPE_LINK))
SKIP("strange class/scope\n");
// ignore rtm_scope, it is not a real scope
// if (i->rtm_scope != RT_SCOPE_UNIVERSE)
// SKIP("scope %u\n", i->rtm_scope);
switch (i->rtm_protocol)
{
case RTPROT_UNSPEC:
SKIP("proto unspec\n");
case RTPROT_REDIRECT:
src = KRT_SRC_REDIRECT;
break;
case RTPROT_KERNEL:
src = KRT_SRC_KERNEL;
return;
case RTPROT_BIRD:
if (!scan)
SKIP("echo\n");
src = KRT_SRC_BIRD;
break;
case RTPROT_BOOT:
default:
src = KRT_SRC_ALIEN;
}
net = net_get(p->p.table, dst, i->rtm_dst_len);
rta ra = {
.proto = &p->p,
.source = RTS_INHERIT,
.scope = SCOPE_UNIVERSE,
.cast = RTC_UNICAST
};
switch (i->rtm_type)
{
case RTN_UNICAST:
if (a[RTA_MULTIPATH])
{
ra.dest = RTD_MULTIPATH;
ra.nexthops = nl_parse_multipath(p, a[RTA_MULTIPATH]);
if (!ra.nexthops)
{
log(L_ERR "KRT: Received strange multipath route %I/%d",
net->n.prefix, net->n.pxlen);
return;
}
break;
}
ra.iface = if_find_by_index(oif);
if (!ra.iface)
{
log(L_ERR "KRT: Received route %I/%d with unknown ifindex %u",
net->n.prefix, net->n.pxlen, oif);
return;
}
if (a[RTA_GATEWAY])
{
neighbor *ng;
ra.dest = RTD_ROUTER;
memcpy(&ra.gw, RTA_DATA(a[RTA_GATEWAY]), sizeof(ra.gw));
ipa_ntoh(ra.gw);
ng = neigh_find2(&p->p, &ra.gw, ra.iface,
(i->rtm_flags & RTNH_F_ONLINK) ? NEF_ONLINK : 0);
if (!ng || (ng->scope == SCOPE_HOST))
{
log(L_ERR "KRT: Received route %I/%d with strange next-hop %I",
net->n.prefix, net->n.pxlen, ra.gw);
return;
}
}
else
{
ra.dest = RTD_DEVICE;
/*
* In Linux IPv6, 'native' device routes have proto
* RTPROT_BOOT and not RTPROT_KERNEL (which they have in
* IPv4 and which is expected). We cannot distinguish
* 'native' and user defined device routes, so we ignore all
* such device routes and for consistency, we have the same
* behavior in IPv4. Anyway, users should use RTPROT_STATIC
* for their 'alien' routes.
*/
if (i->rtm_protocol == RTPROT_BOOT)
src = KRT_SRC_KERNEL;
}
break;
case RTN_BLACKHOLE:
ra.dest = RTD_BLACKHOLE;
break;
case RTN_UNREACHABLE:
ra.dest = RTD_UNREACHABLE;
break;
case RTN_PROHIBIT:
ra.dest = RTD_PROHIBIT;
break;
/* FIXME: What about RTN_THROW? */
default:
SKIP("type %d\n", i->rtm_type);
return;
}
e = rte_get_temp(&ra);
e->net = net;
e->u.krt.src = src;
e->u.krt.proto = i->rtm_protocol;
e->u.krt.type = i->rtm_type;
if (a[RTA_PRIORITY])
memcpy(&e->u.krt.metric, RTA_DATA(a[RTA_PRIORITY]), sizeof(e->u.krt.metric));
else
e->u.krt.metric = 0;
if (scan)
krt_got_route(p, e);
else
krt_got_route_async(p, e, new);
}
void
krt_scan_fire(struct krt_proto *p UNUSED) /* CONFIG_ALL_TABLES_AT_ONCE => p is NULL */
{
struct nlmsghdr *h;
nl_request_dump(RTM_GETROUTE);
while (h = nl_get_scan())
if (h->nlmsg_type == RTM_NEWROUTE || h->nlmsg_type == RTM_DELROUTE)
nl_parse_route(h, 1);
else
log(L_DEBUG "nl_scan_fire: Unknown packet received (type=%d)", h->nlmsg_type);
}
/*
* Asynchronous Netlink interface
*/
static sock *nl_async_sk; /* BIRD socket for asynchronous notifications */
static byte *nl_async_rx_buffer; /* Receive buffer */
static void
nl_async_msg(struct nlmsghdr *h)
{
switch (h->nlmsg_type)
{
case RTM_NEWROUTE:
case RTM_DELROUTE:
DBG("KRT: Received async route notification (%d)\n", h->nlmsg_type);
nl_parse_route(h, 0);
break;
case RTM_NEWLINK:
case RTM_DELLINK:
DBG("KRT: Received async link notification (%d)\n", h->nlmsg_type);
nl_parse_link(h, 0);
break;
case RTM_NEWADDR:
case RTM_DELADDR:
DBG("KRT: Received async address notification (%d)\n", h->nlmsg_type);
nl_parse_addr(h);
break;
default:
DBG("KRT: Received unknown async notification (%d)\n", h->nlmsg_type);
}
}
static int
nl_async_hook(sock *sk, int size UNUSED)
{
struct iovec iov = { nl_async_rx_buffer, NL_RX_SIZE };
struct sockaddr_nl sa;
struct msghdr m = { (struct sockaddr *) &sa, sizeof(sa), &iov, 1, NULL, 0, 0 };
struct nlmsghdr *h;
int x;
unsigned int len;
x = recvmsg(sk->fd, &m, 0);
if (x < 0)
{
if (errno == ENOBUFS)
{
/*
* Netlink reports some packets have been thrown away.
* One day we might react to it by asking for route table
* scan in near future.
*/
return 1; /* More data are likely to be ready */
}
else if (errno != EWOULDBLOCK)
log(L_ERR "Netlink recvmsg: %m");
return 0;
}
if (sa.nl_pid) /* It isn't from the kernel */
{
DBG("Non-kernel packet\n");
return 1;
}
h = (void *) nl_async_rx_buffer;
len = x;
if (m.msg_flags & MSG_TRUNC)
{
log(L_WARN "Netlink got truncated asynchronous message");
return 1;
}
while (NLMSG_OK(h, len))
{
nl_async_msg(h);
h = NLMSG_NEXT(h, len);
}
if (len)
log(L_WARN "nl_async_hook: Found packet remnant of size %d", len);
return 1;
}
static void
nl_open_async(void)
{
sock *sk;
struct sockaddr_nl sa;
int fd;
static int nl_open_tried = 0;
if (nl_open_tried)
return;
nl_open_tried = 1;
DBG("KRT: Opening async netlink socket\n");
fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (fd < 0)
{
log(L_ERR "Unable to open asynchronous rtnetlink socket: %m");
return;
}
bzero(&sa, sizeof(sa));
sa.nl_family = AF_NETLINK;
#ifdef IPV6
sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV6_IFADDR | RTMGRP_IPV6_ROUTE;
#else
sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV4_ROUTE;
#endif
if (bind(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0)
{
log(L_ERR "Unable to bind asynchronous rtnetlink socket: %m");
return;
}
sk = nl_async_sk = sk_new(krt_pool);
sk->type = SK_MAGIC;
sk->rx_hook = nl_async_hook;
sk->fd = fd;
if (sk_open(sk))
bug("Netlink: sk_open failed");
if (!nl_async_rx_buffer)
nl_async_rx_buffer = xmalloc(NL_RX_SIZE);
}
/*
* Interface to the UNIX krt module
*/
static u8 nl_cf_table[(NL_NUM_TABLES+7) / 8];
void
krt_scan_preconfig(struct config *c UNUSED)
{
bzero(&nl_cf_table, sizeof(nl_cf_table));
}
void
krt_scan_postconfig(struct krt_config *x)
{
int id = x->scan.table_id;
if (nl_cf_table[id/8] & (1 << (id%8)))
cf_error("Multiple kernel syncers defined for table #%d", id);
nl_cf_table[id/8] |= (1 << (id%8));
}
void
krt_scan_construct(struct krt_config *x)
{
#ifndef IPV6
x->scan.table_id = RT_TABLE_MAIN;
#else
x->scan.table_id = 254;
#endif
}
void
krt_scan_start(struct krt_proto *p, int first)
{
init_list(&p->scan.temp_ifs);
nl_table_map[KRT_CF->scan.table_id] = p;
if (first)
{
nl_open();
nl_open_async();
}
}
void
krt_scan_shutdown(struct krt_proto *p UNUSED, int last UNUSED)
{
}
void
krt_if_start(struct kif_proto *p UNUSED)
{
nl_open();
nl_open_async();
}
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