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bird/sysdep/linux/netlink.c
Jan Moskyto Matejka ad27615760 Netlink: attribute validation before parsing 
Wanted netlink attributes are defined in a table, specifying
their size and neediness. Removing the long conditions that did the
validation before.

Also parsing IPv4 and IPv6 versions regardless on the IPV6 macro.
2015-11-24 14:30:20 +01:00

1431 lines
32 KiB
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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 <unistd.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/alloca.h"
#include "lib/timer.h"
#include "lib/unix.h"
#include "lib/krt.h"
#include "lib/socket.h"
#include "lib/string.h"
#include "lib/hash.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
#ifndef RTA_TABLE
#define RTA_TABLE 15
#endif
/*
* Synchronous Netlink interface
*/
struct nl_sock
{
int fd;
u32 seq;
byte *rx_buffer; /* Receive buffer */
struct nlmsghdr *last_hdr; /* Recently received packet */
uint 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 af, int cmd)
{
struct {
struct nlmsghdr nh;
struct rtgenmsg g;
} req = {
.nh.nlmsg_type = cmd,
.nh.nlmsg_len = sizeof(req),
.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP,
.g.rtgen_family = af
};
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 tbf rl_netlink_err = TBF_DEFAULT_LOG_LIMITS;
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) ? -1 : 0;
}
/*
* 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);
}
struct nl_want_attrs {
u8 defined:1;
u8 checksize:1;
u8 size;
};
#define BIRD_IFLA_MAX (IFLA_WIRELESS+1)
static struct nl_want_attrs ifla_attr_want[BIRD_IFLA_MAX] = {
[IFLA_IFNAME] = { 1, 0, 0 },
[IFLA_MTU] = { 1, 1, sizeof(u32) },
[IFLA_WIRELESS] = { 1, 0, 0 },
};
#define BIRD_IFA_MAX (IFA_ANYCAST+1)
#ifndef IPV6
static struct nl_want_attrs ifa_attr_want4[BIRD_IFA_MAX] = {
[IFA_ADDRESS] = { 1, 1, sizeof(ip4_addr) },
[IFA_LOCAL] = { 1, 1, sizeof(ip4_addr) },
[IFA_BROADCAST] = { 1, 1, sizeof(ip4_addr) },
};
#else
static struct nl_want_attrs ifa_attr_want6[BIRD_IFA_MAX] = {
[IFA_ADDRESS] = { 1, 1, sizeof(ip6_addr) },
[IFA_LOCAL] = { 1, 1, sizeof(ip6_addr) },
};
#endif
#define BIRD_RTA_MAX (RTA_TABLE+1)
static struct nl_want_attrs mpnh_attr_want4[BIRD_RTA_MAX] = {
[RTA_GATEWAY] = { 1, 1, sizeof(ip4_addr) },
};
#ifndef IPV6
static struct nl_want_attrs rtm_attr_want4[BIRD_RTA_MAX] = {
[RTA_DST] = { 1, 1, sizeof(ip4_addr) },
[RTA_OIF] = { 1, 1, sizeof(u32) },
[RTA_GATEWAY] = { 1, 1, sizeof(ip4_addr) },
[RTA_PRIORITY] = { 1, 1, sizeof(u32) },
[RTA_PREFSRC] = { 1, 1, sizeof(ip4_addr) },
[RTA_METRICS] = { 1, 0, 0 },
[RTA_MULTIPATH] = { 1, 0, 0 },
[RTA_FLOW] = { 1, 1, sizeof(u32) },
[RTA_TABLE] = { 1, 1, sizeof(u32) },
};
#else
static struct nl_want_attrs rtm_attr_want6[BIRD_RTA_MAX] = {
[RTA_DST] = { 1, 1, sizeof(ip6_addr) },
[RTA_IIF] = { 1, 1, sizeof(u32) },
[RTA_OIF] = { 1, 1, sizeof(u32) },
[RTA_GATEWAY] = { 1, 1, sizeof(ip6_addr) },
[RTA_PRIORITY] = { 1, 1, sizeof(u32) },
[RTA_PREFSRC] = { 1, 1, sizeof(ip6_addr) },
[RTA_METRICS] = { 1, 0, 0 },
[RTA_FLOW] = { 1, 1, sizeof(u32) },
[RTA_TABLE] = { 1, 1, sizeof(u32) },
};
#endif
static int
nl_parse_attrs(struct rtattr *a, struct nl_want_attrs *want, struct rtattr **k, int ksize)
{
int max = ksize / sizeof(struct rtattr *);
bzero(k, ksize);
for ( ; RTA_OK(a, nl_attr_len); a = RTA_NEXT(a, nl_attr_len))
{
if ((a->rta_type >= max) || !want[a->rta_type].defined)
continue;
if (want[a->rta_type].checksize && (RTA_PAYLOAD(a) != want[a->rta_type].size))
{
log(L_ERR "nl_parse_attrs: Malformed message received");
return 0;
}
k[a->rta_type] = a;
}
if (nl_attr_len)
{
log(L_ERR "nl_parse_attrs: remnant of size %d", nl_attr_len);
return 0;
}
return 1;
}
static inline u32 rta_get_u32(struct rtattr *a)
{ return *(u32 *) RTA_DATA(a); }
static inline ip4_addr rta_get_ip4(struct rtattr *a)
{ return ip4_ntoh(*(ip4_addr *) RTA_DATA(a)); }
static inline ip6_addr rta_get_ip6(struct rtattr *a)
{ return ip6_ntoh(*(ip6_addr *) RTA_DATA(a)); }
struct rtattr *
nl_add_attr(struct nlmsghdr *h, uint bufsize, uint code, const void *data, uint dlen)
{
uint pos = NLMSG_ALIGN(h->nlmsg_len);
uint len = RTA_LENGTH(dlen);
if (pos + len > bufsize)
bug("nl_add_attr: packet buffer overflow");
struct rtattr *a = (struct rtattr *)((char *)h + pos);
a->rta_type = code;
a->rta_len = len;
h->nlmsg_len = pos + len;
if (dlen > 0)
memcpy(RTA_DATA(a), data, dlen);
return a;
}
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));
}
static inline struct rtattr *
nl_open_attr(struct nlmsghdr *h, uint bufsize, uint code)
{
return nl_add_attr(h, bufsize, code, NULL, 0);
}
static inline void
nl_close_attr(struct nlmsghdr *h, struct rtattr *a)
{
a->rta_len = (void *)h + NLMSG_ALIGN(h->nlmsg_len) - (void *)a;
}
static inline struct rtnexthop *
nl_open_nexthop(struct nlmsghdr *h, uint bufsize)
{
uint pos = NLMSG_ALIGN(h->nlmsg_len);
uint len = RTNH_LENGTH(0);
if (pos + len > bufsize)
bug("nl_open_nexthop: packet buffer overflow");
h->nlmsg_len = pos + len;
return (void *)h + pos;
}
static inline void
nl_close_nexthop(struct nlmsghdr *h, struct rtnexthop *nh)
{
nh->rtnh_len = (void *)h + NLMSG_ALIGN(h->nlmsg_len) - (void *)nh;
}
static void
nl_add_multipath(struct nlmsghdr *h, unsigned bufsize, struct mpnh *nh)
{
struct rtattr *a = nl_open_attr(h, bufsize, RTA_MULTIPATH);
for (; nh; nh = nh->next)
{
struct rtnexthop *rtnh = nl_open_nexthop(h, bufsize);
rtnh->rtnh_flags = 0;
rtnh->rtnh_hops = nh->weight;
rtnh->rtnh_ifindex = nh->iface->index;
nl_add_attr_ipa(h, bufsize, RTA_GATEWAY, nh->gw);
nl_close_nexthop(h, rtnh);
}
nl_close_attr(h, a);
}
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[BIRD_RTA_MAX];
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), mpnh_attr_want4, a, sizeof(a));
if (a[RTA_GATEWAY])
{
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;
}
static void
nl_add_metrics(struct nlmsghdr *h, uint bufsize, u32 *metrics, int max)
{
struct rtattr *a = nl_open_attr(h, bufsize, RTA_METRICS);
int t;
for (t = 1; t < max; t++)
if (metrics[0] & (1 << t))
nl_add_attr_u32(h, bufsize, t, metrics[t]);
nl_close_attr(h, a);
}
static int
nl_parse_metrics(struct rtattr *hdr, u32 *metrics, int max)
{
struct rtattr *a = RTA_DATA(hdr);
int len = RTA_PAYLOAD(hdr);
metrics[0] = 0;
for (; RTA_OK(a, len); a = RTA_NEXT(a, len))
{
if (a->rta_type == RTA_UNSPEC)
continue;
if (a->rta_type >= max)
continue;
if (RTA_PAYLOAD(a) != 4)
return -1;
metrics[0] |= 1 << a->rta_type;
metrics[a->rta_type] = rta_get_u32(a);
}
if (len > 0)
return -1;
return 0;
}
/*
* Scanning of interfaces
*/
static void
nl_parse_link(struct nlmsghdr *h, int scan)
{
struct ifinfomsg *i;
struct rtattr *a[BIRD_IFLA_MAX];
int new = h->nlmsg_type == RTM_NEWLINK;
struct iface f = {};
struct iface *ifi;
char *name;
u32 mtu;
uint fl;
if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFLA_RTA(i), ifla_attr_want, a, sizeof(a)))
return;
if (!a[IFLA_IFNAME] || (RTA_PAYLOAD(a[IFLA_IFNAME]) < 2) || !a[IFLA_MTU])
{
/*
* IFLA_IFNAME and IFLA_MTU are required, in fact, but there may also come
* a message with IFLA_WIRELESS set, where (e.g.) no IFLA_IFNAME exists.
* We simply ignore all such messages with IFLA_WIRELESS without notice.
*/
if (a[IFLA_WIRELESS])
return;
log(L_ERR "KIF: Malformed message received");
return;
}
name = RTA_DATA(a[IFLA_IFNAME]);
mtu = rta_get_u32(a[IFLA_MTU]);
ifi = if_find_by_index(i->ifi_index);
if (!new)
{
DBG("KIF: IF%d(%s) goes down\n", i->ifi_index, name);
if (!ifi)
return;
if_delete(ifi);
}
else
{
DBG("KIF: IF%d(%s) goes up (mtu=%d,flg=%x)\n", i->ifi_index, name, mtu, i->ifi_flags);
if (ifi && strncmp(ifi->name, name, sizeof(ifi->name)-1))
if_delete(ifi);
strncpy(f.name, name, sizeof(f.name)-1);
f.index = i->ifi_index;
f.mtu = mtu;
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 (fl & IFF_MULTICAST)
f.flags |= IF_MULTICAST;
ifi = if_update(&f);
if (!scan)
if_end_partial_update(ifi);
}
}
static void
nl_parse_addr(struct nlmsghdr *h, int scan)
{
struct ifaddrmsg *i;
struct rtattr *a[BIRD_IFA_MAX];
int new = h->nlmsg_type == RTM_NEWADDR;
struct ifa ifa;
struct iface *ifi;
int scope;
if (!(i = nl_checkin(h, sizeof(*i))))
return;
switch (i->ifa_family)
{
#ifndef IPV6
case AF_INET:
if (!nl_parse_attrs(IFA_RTA(i), ifa_attr_want4, a, sizeof(a)))
return;
if (!a[IFA_LOCAL])
{
log(L_ERR "KIF: Malformed message received (missing IFA_LOCAL)");
return;
}
break;
#else
case AF_INET6:
if (!nl_parse_attrs(IFA_RTA(i), ifa_attr_want6, a, sizeof(a)))
return;
break;
#endif
default:
return;
}
if (!a[IFA_ADDRESS])
{
log(L_ERR "KIF: Malformed message received (missing IFA_ADDRESS)");
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 host address or a peer address */
if (ipa_equal(ifa.ip, addr))
ifa.flags |= IA_HOST;
else
{
ifa.flags |= IA_PEER;
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);
if (!scan)
if_end_partial_update(ifi);
}
void
kif_do_scan(struct kif_proto *p UNUSED)
{
struct nlmsghdr *h;
if_start_update();
nl_request_dump(AF_UNSPEC, 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(BIRD_AF, RTM_GETADDR);
while (h = nl_get_scan())
if (h->nlmsg_type == RTM_NEWADDR || h->nlmsg_type == RTM_DELADDR)
nl_parse_addr(h, 1);
else
log(L_DEBUG "nl_scan_ifaces: Unknown packet received (type=%d)", h->nlmsg_type);
if_end_update();
}
/*
* Routes
*/
static inline u32
krt_table_id(struct krt_proto *p)
{
return KRT_CF->sys.table_id;
}
static HASH(struct krt_proto) nl_table_map;
#define RTH_FN(k) u32_hash(k)
#define RTH_EQ(k1,k2) k1 == k2
#define RTH_KEY(p) krt_table_id(p)
#define RTH_NEXT(p) p->sys.hash_next
#define RTH_REHASH rth_rehash
#define RTH_PARAMS /8, *2, 2, 2, 6, 20
HASH_DEFINE_REHASH_FN(RTH, struct krt_proto)
int
krt_capable(rte *e)
{
rta *a = e->attrs;
if (a->cast != RTC_UNICAST)
return 0;
switch (a->dest)
{
case RTD_ROUTER:
case RTD_DEVICE:
if (a->iface == NULL)
return 0;
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_LENGTH(RTA_LENGTH(sizeof(ip_addr)));
return rv;
}
static int
nl_send_route(struct krt_proto *p, rte *e, struct ea_list *eattrs, int new)
{
eattr *ea;
net *net = e->net;
rta *a = e->attrs;
struct {
struct nlmsghdr h;
struct rtmsg r;
char buf[128 + KRT_METRICS_MAX*8 + 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_protocol = RTPROT_BIRD;
r.r.rtm_scope = RT_SCOPE_UNIVERSE;
nl_add_attr_ipa(&r.h, sizeof(r), RTA_DST, net->n.prefix);
if (krt_table_id(p) < 256)
r.r.rtm_table = krt_table_id(p);
else
nl_add_attr_u32(&r.h, sizeof(r), RTA_TABLE, krt_table_id(p));
/* For route delete, we do not specify route attributes */
if (!new)
return nl_exchange(&r.h);
if (ea = ea_find(eattrs, EA_KRT_METRIC))
nl_add_attr_u32(&r.h, sizeof(r), RTA_PRIORITY, ea->u.data);
if (ea = ea_find(eattrs, EA_KRT_PREFSRC))
nl_add_attr_ipa(&r.h, sizeof(r), RTA_PREFSRC, *(ip_addr *)ea->u.ptr->data);
if (ea = ea_find(eattrs, EA_KRT_REALM))
nl_add_attr_u32(&r.h, sizeof(r), RTA_FLOW, ea->u.data);
u32 metrics[KRT_METRICS_MAX];
metrics[0] = 0;
struct ea_walk_state ews = { .eattrs = eattrs };
while (ea = ea_walk(&ews, EA_KRT_METRICS, KRT_METRICS_MAX))
{
int id = ea->id - EA_KRT_METRICS;
metrics[0] |= 1 << id;
metrics[id] = ea->u.data;
}
if (metrics[0])
nl_add_metrics(&r.h, sizeof(r), metrics, KRT_METRICS_MAX);
/* a->iface != NULL checked in krt_capable() for router and device routes */
switch (a->dest)
{
case RTD_ROUTER:
r.r.rtm_type = RTN_UNICAST;
nl_add_attr_u32(&r.h, sizeof(r), RTA_OIF, a->iface->index);
nl_add_attr_ipa(&r.h, sizeof(r), RTA_GATEWAY, a->gw);
break;
case RTD_DEVICE:
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");
}
return nl_exchange(&r.h);
}
void
krt_replace_rte(struct krt_proto *p, net *n, rte *new, rte *old, struct ea_list *eattrs)
{
int err = 0;
/*
* NULL for eattr of the old route is a little hack, but we don't
* get proper eattrs for old in rt_notify() anyway. NULL means no
* extended route attributes and therefore matches if the kernel
* route has any of them.
*/
if (old)
nl_send_route(p, old, NULL, 0);
if (new)
err = nl_send_route(p, new, eattrs, 1);
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
nl_parse_route(struct nlmsghdr *h, int scan)
{
struct krt_proto *p;
struct rtmsg *i;
struct rtattr *a[BIRD_RTA_MAX];
int new = h->nlmsg_type == RTM_NEWROUTE;
ip_addr dst = IPA_NONE;
u32 oif = ~0;
u32 table;
int src;
if (!(i = nl_checkin(h, sizeof(*i))))
return;
switch (i->rtm_family)
{
#ifndef IPV6
case AF_INET:
if (!nl_parse_attrs(RTM_RTA(i), rtm_attr_want4, a, sizeof(a)))
return;
break;
#else
case AF_INET6:
if (!nl_parse_attrs(RTM_RTA(i), rtm_attr_want6, a, sizeof(a)))
return;
break;
#endif
default:
return;
}
if (a[RTA_DST])
{
memcpy(&dst, RTA_DATA(a[RTA_DST]), sizeof(dst));
ipa_ntoh(dst);
}
if (a[RTA_OIF])
oif = rta_get_u32(a[RTA_OIF]);
if (a[RTA_TABLE])
table = rta_get_u32(a[RTA_TABLE]);
else
table = i->rtm_table;
p = HASH_FIND(nl_table_map, RTH, table); /* Do we know this table? */
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, table, i->rtm_protocol, p ? p->p.name : "(none)");
if (!p)
SKIP("unknown table %d\n", 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 = net_get(p->p.table, dst, i->rtm_dst_len);
rta ra = {
.src= p->p.main_source,
.source = RTS_INHERIT,
.scope = SCOPE_UNIVERSE,
.cast = RTC_UNICAST
};
switch (i->rtm_type)
{
case RTN_UNICAST:
if (a[RTA_MULTIPATH] && (i->rtm_family == AF_INET))
{
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);
#ifdef IPV6
/* Silently skip strange 6to4 routes */
if (ipa_in_net(ra.gw, IPA_NONE, 96))
return;
#endif
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;
}
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;
}
rte *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;
e->u.krt.metric = 0;
if (a[RTA_PRIORITY])
e->u.krt.metric = rta_get_u32(a[RTA_PRIORITY]);
if (a[RTA_PREFSRC])
{
ip_addr ps;
memcpy(&ps, RTA_DATA(a[RTA_PREFSRC]), sizeof(ps));
ipa_ntoh(ps);
ea_list *ea = alloca(sizeof(ea_list) + sizeof(eattr));
ea->next = ra.eattrs;
ra.eattrs = ea;
ea->flags = EALF_SORTED;
ea->count = 1;
ea->attrs[0].id = EA_KRT_PREFSRC;
ea->attrs[0].flags = 0;
ea->attrs[0].type = EAF_TYPE_IP_ADDRESS;
ea->attrs[0].u.ptr = alloca(sizeof(struct adata) + sizeof(ps));
ea->attrs[0].u.ptr->length = sizeof(ps);
memcpy(ea->attrs[0].u.ptr->data, &ps, sizeof(ps));
}
if (a[RTA_FLOW])
{
ea_list *ea = alloca(sizeof(ea_list) + sizeof(eattr));
ea->next = ra.eattrs;
ra.eattrs = ea;
ea->flags = EALF_SORTED;
ea->count = 1;
ea->attrs[0].id = EA_KRT_REALM;
ea->attrs[0].flags = 0;
ea->attrs[0].type = EAF_TYPE_INT;
ea->attrs[0].u.data = rta_get_u32(a[RTA_FLOW]);
}
if (a[RTA_METRICS])
{
u32 metrics[KRT_METRICS_MAX];
ea_list *ea = alloca(sizeof(ea_list) + KRT_METRICS_MAX * sizeof(eattr));
int t, n = 0;
if (nl_parse_metrics(a[RTA_METRICS], metrics, ARRAY_SIZE(metrics)) < 0)
{
log(L_ERR "KRT: Received route %I/%d with strange RTA_METRICS attribute",
net->n.prefix, net->n.pxlen);
return;
}
for (t = 1; t < KRT_METRICS_MAX; t++)
if (metrics[0] & (1 << t))
{
ea->attrs[n].id = EA_CODE(EAP_KRT, KRT_METRICS_OFFSET + t);
ea->attrs[n].flags = 0;
ea->attrs[n].type = EAF_TYPE_INT; /* FIXME: Some are EAF_TYPE_BITFIELD */
ea->attrs[n].u.data = metrics[t];
n++;
}
if (n > 0)
{
ea->next = ra.eattrs;
ea->flags = EALF_SORTED;
ea->count = n;
ra.eattrs = ea;
}
}
if (scan)
krt_got_route(p, e);
else
krt_got_route_async(p, e, new);
}
void
krt_do_scan(struct krt_proto *p UNUSED) /* CONFIG_ALL_TABLES_AT_ONCE => p is NULL */
{
struct nlmsghdr *h;
nl_request_dump(BIRD_AF, 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);
if (kif_proto)
nl_parse_link(h, 0);
break;
case RTM_NEWADDR:
case RTM_DELADDR:
DBG("KRT: Received async address notification (%d)\n", h->nlmsg_type);
if (kif_proto)
nl_parse_addr(h, 0);
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;
uint 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;
if (nl_async_sk)
return;
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");
close(fd);
return;
}
nl_async_rx_buffer = xmalloc(NL_RX_SIZE);
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) < 0)
bug("Netlink: sk_open failed");
}
/*
* Interface to the UNIX krt module
*/
void
krt_sys_io_init(void)
{
HASH_INIT(nl_table_map, krt_pool, 6);
}
int
krt_sys_start(struct krt_proto *p)
{
struct krt_proto *old = HASH_FIND(nl_table_map, RTH, krt_table_id(p));
if (old)
{
log(L_ERR "%s: Kernel table %u already registered by %s",
p->p.name, krt_table_id(p), old->p.name);
return 0;
}
HASH_INSERT2(nl_table_map, RTH, krt_pool, p);
nl_open();
nl_open_async();
return 1;
}
void
krt_sys_shutdown(struct krt_proto *p)
{
HASH_REMOVE2(nl_table_map, RTH, krt_pool, p);
}
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_init_config(struct krt_config *cf)
{
cf->sys.table_id = RT_TABLE_MAIN;
}
void
krt_sys_copy_config(struct krt_config *d, struct krt_config *s)
{
d->sys.table_id = s->sys.table_id;
}
static const char *krt_metrics_names[KRT_METRICS_MAX] = {
NULL, "lock", "mtu", "window", "rtt", "rttvar", "sstresh", "cwnd", "advmss",
"reordering", "hoplimit", "initcwnd", "features", "rto_min", "initrwnd", "quickack"
};
static const char *krt_features_names[KRT_FEATURES_MAX] = {
"ecn", NULL, NULL, "allfrag"
};
int
krt_sys_get_attr(eattr *a, byte *buf, int buflen UNUSED)
{
switch (a->id)
{
case EA_KRT_PREFSRC:
bsprintf(buf, "prefsrc");
return GA_NAME;
case EA_KRT_REALM:
bsprintf(buf, "realm");
return GA_NAME;
case EA_KRT_LOCK:
buf += bsprintf(buf, "lock:");
ea_format_bitfield(a, buf, buflen, krt_metrics_names, 2, KRT_METRICS_MAX);
return GA_FULL;
case EA_KRT_FEATURES:
buf += bsprintf(buf, "features:");
ea_format_bitfield(a, buf, buflen, krt_features_names, 0, KRT_FEATURES_MAX);
return GA_FULL;
default:;
int id = (int)EA_ID(a->id) - KRT_METRICS_OFFSET;
if (id > 0 && id < KRT_METRICS_MAX)
{
bsprintf(buf, "%s", krt_metrics_names[id]);
return GA_NAME;
}
return GA_UNKNOWN;
}
}
void
kif_sys_start(struct kif_proto *p UNUSED)
{
nl_open();
nl_open_async();
}
void
kif_sys_shutdown(struct kif_proto *p UNUSED)
{
}
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