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bird/sysdep/linux/netlink.c

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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 "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 pf, 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;
req.g.rtgen_family = 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) ? -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);
}
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;
}
#define IPSIZE(ipv4) ((ipv4) ? sizeof(ip4_addr) : sizeof(ip6_addr))
static inline ip4_addr rta4_get_ip4(struct rtattr *a)
{ return ip4_get(RTA_DATA(a)); }
static inline ip6_addr rta6_get_ip6(struct rtattr *a)
{ return ip6_get(RTA_DATA(a)); }
static inline ip_addr rta4_get_ipa(struct rtattr *a)
{ return ipa_from_ip4(ip4_get(RTA_DATA(a))); }
static inline ip_addr rta6_get_ipa(struct rtattr *a)
{ return ipa_from_ip6(ip6_get(RTA_DATA(a))); }
static inline ip_addr rtax_get_ipa(struct rtattr *a, const int ipv4)
{ return ipv4 ? rta4_get_ipa(a) : rta6_get_ipa(a); }
static inline void ipax_put(void *buf, ip_addr a, const int ipv4)
{ if (ipv4) ip4_put(buf, ipa_to_ip4(a)); else ip6_put(buf, ipa_to_ip6(a)); }
void *
nl_add_attr(struct nlmsghdr *h, unsigned bufsize, unsigned code, 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;
return RTA_DATA(a);
}
static inline void
nl_add_attr_u32(struct nlmsghdr *h, unsigned bufsize, int code, u32 data)
{
void *buf = nl_add_attr(h, bufsize, code, 4);
memcpy(buf, &data, 4);
}
static inline void
nl_add_attr_ipa(struct nlmsghdr *h, unsigned bufsize, int code, ip_addr ipa, const int ipv4)
{
void *buf = nl_add_attr(h, bufsize, code, IPSIZE(ipv4));
ipax_put(buf, ipa, ipv4);
}
#define RTNH_SIZE(ipv4) (sizeof(struct rtnexthop) + sizeof(struct rtattr) + IPSIZE(ipv4))
static inline void
add_mpnexthop(char *buf, ip_addr ipa, const int ipv4, unsigned iface, unsigned char weight)
{
struct rtnexthop *nh = (void *) buf;
struct rtattr *rt = (void *) (buf + sizeof(*nh));
nh->rtnh_len = RTNH_SIZE(ipv4);
nh->rtnh_flags = 0;
nh->rtnh_hops = weight;
nh->rtnh_ifindex = iface;
rt->rta_len = sizeof(*rt) + IPSIZE(ipv4);
rt->rta_type = RTA_GATEWAY;
ipax_put(buf + sizeof(*nh) + sizeof(*rt), ipa, ipv4);
}
static void
nl_add_multipath(struct nlmsghdr *h, unsigned bufsize, struct mpnh *nh, const int ipv4)
{
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(ipv4);
if (pos + len > bufsize)
bug("nl_add_multipath: packet buffer overflow");
add_mpnexthop(buf, nh->gw, ipv4, nh->iface->index, nh->weight);
buf += RTNH_SIZE(ipv4);
}
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, const int ipv4)
{
/* 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]) != IPSIZE(ipv4))
return NULL;
rv->gw = rtax_get_ipa(a[RTA_GATEWAY], ipv4);
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)
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_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;
ip_addr addr;
int ipv4 = 0;
if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFA_RTA(i), a, sizeof(a)))
return;
bzero(&ifa, sizeof(ifa));
if (i->ifa_family == AF_INET)
{
if (!a[IFA_ADDRESS] || (RTA_PAYLOAD(a[IFA_ADDRESS]) != sizeof(ip4_addr)) ||
!a[IFA_LOCAL] || (RTA_PAYLOAD(a[IFA_LOCAL]) != sizeof(ip4_addr)))
goto malformed;
addr = rta4_get_ipa(a[IFA_ADDRESS]);
ifa.ip = rta4_get_ipa(a[IFA_LOCAL]);
ipv4 = 1;
}
else if (i->ifa_family == AF_INET6)
{
if (!a[IFA_ADDRESS] || (RTA_PAYLOAD(a[IFA_ADDRESS]) != sizeof(ip6_addr)) ||
(a[IFA_LOCAL] && (RTA_PAYLOAD(a[IFA_LOCAL]) != sizeof(ip6_addr))))
goto malformed;
addr = rta6_get_ipa(a[IFA_ADDRESS]);
/* IFA_LOCAL can be unset for IPv6 interfaces */
ifa.ip = a[IFA_LOCAL] ? rta6_get_ipa(a[IFA_LOCAL]) : addr;
}
else
return; /* Ignore unknown address families */
ifa.iface = if_find_by_index(i->ifa_index);
if (!ifa.iface)
{
log(L_ERR "KIF: Received address message for unknown interface %d", i->ifa_index);
return;
}
if (i->ifa_flags & IFA_F_SECONDARY)
ifa.flags |= IA_SECONDARY;
ifa.pxlen = i->ifa_prefixlen + (ipv4 ? 96 : 0); // XXXX: Hack
if (ifa.pxlen > BITS_PER_IP_ADDRESS)
{
log(L_ERR "KIF: Received invalid pxlen %d on %s", i->ifa_prefixlen, ifa.iface->name);
return;
}
if (i->ifa_prefixlen == BITS_PER_IP_ADDRESS)
{
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(addr, netmask);
ifa.brd = ipa_or(addr, ipa_not(netmask));
if (i->ifa_prefixlen == BITS_PER_IP_ADDRESS - 1)
ifa.opposite = ipa_opposite_m1(ifa.ip);
if ((i->ifa_prefixlen == BITS_PER_IP_ADDRESS - 2) && ipv4)
ifa.opposite = ipa_opposite_m2(ifa.ip);
}
int scope = ipa_classify(ifa.ip);
if ((scope == IADDR_INVALID) || !(scope & IADDR_HOST))
{
log(L_ERR "KIF: Received invalid address %I on %s", ifa.ip, ifa.iface->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",
ifa.iface->index, ifa.iface->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);
return;
malformed:
log(L_ERR "KIF: Received malformed address message");
return;
}
void
kif_do_scan(struct kif_proto *p UNUSED)
{
struct nlmsghdr *h;
if_start_update();
/* 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. */
nl_request_dump(PF_INET, 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(PF_INET, 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);
nl_request_dump(PF_INET6, 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_table4_map[NL_NUM_TABLES];
static struct krt_proto *nl_table6_map[NL_NUM_TABLES];
#define nl_tablex_map(x) (x ? nl_table4_map : nl_table6_map)
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, const int ipv4)
{
int rv = 0;
for (; nh != NULL; nh = nh->next)
rv += RTNH_SIZE(ipv4);
return rv;
}
static int
nl_send_route(struct krt_proto *p, rte *e, struct ea_list *eattrs, int new)
{
int ipv4 = (p->addr_type == RT_IPV4);
eattr *ea;
net *net = e->net;
rta *a = e->attrs;
struct {
struct nlmsghdr h;
struct rtmsg r;
char buf[128 + nh_bufsize(a->nexthops, ipv4)];
} r;
DBG("nl_send_route(%F,new=%d)\n", &net->n, 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 = ipv4 ? AF_INET : AF_INET6;
r.r.rtm_dst_len = net->n.pxlen - (ipv4 ? 96 : 0); // XXXX: Hack;
r.r.rtm_tos = 0;
r.r.rtm_table = KRT_CF->sys.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, *FPREFIX_IP(&net->n), ipv4);
u32 metric = 0;
if (new && e->attrs->source == RTS_INHERIT)
metric = e->u.krt.metric;
if (ea = ea_find(eattrs, EA_KRT_METRIC))
metric = ea->u.data;
if (metric != 0)
nl_add_attr_u32(&r.h, sizeof(r), RTA_PRIORITY, metric);
if (ea = ea_find(eattrs, EA_KRT_PREFSRC))
nl_add_attr_ipa(&r.h, sizeof(r), RTA_PREFSRC, *(ip_addr *)ea->u.ptr->data, ipv4);
if (ea = ea_find(eattrs, EA_KRT_REALM))
nl_add_attr_u32(&r.h, sizeof(r), RTA_FLOW, ea->u.data);
/* 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, ipv4);
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, ipv4);
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)
{
// log(L_WARN "KRT: %p OLD %I/%d GW %I", p, n->n.prefix, n->n.pxlen, old->attrs->gw);
nl_send_route(p, old, NULL, 0);
}
if (new)
{
// log(L_WARN "KRT: %p NEW %I/%d %I/%d GW %I", p, n->n.prefix, n->n.pxlen, new->attrs->gw);
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[RTA_CACHEINFO+1];
int new = h->nlmsg_type == RTM_NEWROUTE;
ip_addr dst = IPA_NONE;
u32 oif = ~0;
int src, ipv4, ipsize;
if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(RTM_RTA(i), a, sizeof(a)))
return;
if (i->rtm_family == AF_INET)
ipv4 = 1;
else if (i->rtm_family == AF_INET6)
ipv4 = 0;
else
return; /* Ignore unknown address families */
ipsize = IPSIZE(ipv4);
if ((a[RTA_DST] && RTA_PAYLOAD(a[RTA_DST]) != ipsize) ||
(a[RTA_IIF] && RTA_PAYLOAD(a[RTA_IIF]) != 4) ||
(a[RTA_OIF] && RTA_PAYLOAD(a[RTA_OIF]) != 4) ||
(a[RTA_GATEWAY] && RTA_PAYLOAD(a[RTA_GATEWAY]) != ipsize) ||
(a[RTA_PRIORITY] && RTA_PAYLOAD(a[RTA_PRIORITY]) != 4) ||
(a[RTA_PREFSRC] && RTA_PAYLOAD(a[RTA_PREFSRC]) != ipsize) ||
(a[RTA_FLOW] && RTA_PAYLOAD(a[RTA_FLOW]) != 4))
{
log(L_ERR "KRT: Malformed message received");
return;
}
if (a[RTA_DST])
dst = rtax_get_ipa(a[RTA_DST], ipv4);
else if (ipv4) // XXXX hack
dst = ipa_build4(0,0,0,0);
if (a[RTA_OIF])
memcpy(&oif, RTA_DATA(a[RTA_OIF]), sizeof(oif));
DBG("KRT: Got %I/%d, type=%d, oif=%d, table=%d, prid=%d\n", dst, i->rtm_dst_len, i->rtm_type, oif, i->rtm_table, i->rtm_protocol);
p = nl_tablex_map(ipv4)[i->rtm_table];
if (!p) /* We don't know this table */
SKIP("unknown table %d\n", i->rtm_table);
if (a[RTA_IIF]) /* We don't support IIF */
SKIP("IIF set\n");
if (i->rtm_tos != 0) /* We don't support TOS */
SKIP("TOS %02x\n", i->rtm_tos);
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;
}
int pxlen = i->rtm_dst_len + (ipv4 ? 96 : 0); // XXXX: Hack
net *net = net_get(p->p.table, dst, pxlen);
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], ipv4);
if (!ra.nexthops)
{
log(L_ERR "KRT: Received strange multipath route %F", &net->n);
return;
}
break;
}
ra.iface = if_find_by_index(oif);
if (!ra.iface)
{
log(L_ERR "KRT: Received route %F with unknown ifindex %u", &net->n, oif);
return;
}
if (a[RTA_GATEWAY])
{
neighbor *ng;
ra.dest = RTD_ROUTER;
ra.gw = rtax_get_ipa(a[RTA_GATEWAY], ipv4);
#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 %F with strange next-hop %I",
&net->n, 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;
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 (a[RTA_PREFSRC])
{
ip_addr ps = rtax_get_ipa(a[RTA_PREFSRC], ipv4);
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;
memcpy(&ea->attrs[0].u.data, RTA_DATA(a[RTA_FLOW]), 4);
}
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(PF_INET, 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);
nl_request_dump(PF_INET6, 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;
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;
sa.nl_groups = RTMGRP_LINK |
RTMGRP_IPV4_IFADDR | RTMGRP_IPV4_ROUTE |
RTMGRP_IPV6_IFADDR | RTMGRP_IPV6_ROUTE;
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))
bug("Netlink: sk_open failed");
}
/*
* Interface to the UNIX krt module
*/
void
krt_sys_start(struct krt_proto *p)
{
nl_tablex_map(p->addr_type == RT_IPV4)[KRT_CF->sys.table_id] = p;
nl_open();
nl_open_async();
}
void
krt_sys_shutdown(struct krt_proto *p UNUSED)
{
nl_tablex_map(p->addr_type == RT_IPV4)[KRT_CF->sys.table_id] = NULL;
}
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;
}
static u32 nl_table4_cf[(NL_NUM_TABLES+31) / 32];
static u32 nl_table6_cf[(NL_NUM_TABLES+31) / 32];
void
krt_sys_preconfig(struct config *c UNUSED)
{
bzero(&nl_table4_cf, sizeof(nl_table4_cf));
bzero(&nl_table6_cf, sizeof(nl_table6_cf));
}
void
krt_sys_postconfig(struct krt_config *x)
{
u32 *tbl = (x->c.table->addr_type == RT_IPV4) ? nl_table4_cf : nl_table6_cf;
u32 id = x->sys.table_id;
if (tbl[id/32] & (1 << (id%32)))
cf_error("Multiple kernel syncers defined for table #%d", id);
tbl[id/32] |= (1 << (id%32));
}
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;
}
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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