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bird/sysdep/linux/netlink/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 <fcntl.h>
#include <net/if.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/netlink.h>
#include <linux/rtnetlink.h>
#ifndef MSG_TRUNC /* Hack: Several versions of glibc miss this one :( */
#define MSG_TRUNC 0x20
#endif
/*
* Synchronous Netlink interface
*/
static int nl_sync_fd = -1; /* Unix socket for synchronous netlink actions */
static u32 nl_sync_seq; /* Sequence number of last request sent */
static byte *nl_rx_buffer; /* Receive buffer */
#define NL_RX_SIZE 8192
static struct nlmsghdr *nl_last_hdr; /* Recently received packet */
static unsigned int nl_last_size;
static void
nl_open(void)
{
if (nl_sync_fd < 0)
{
nl_sync_fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (nl_sync_fd < 0)
die("Unable to open rtnetlink socket: %m");
nl_sync_seq = now;
nl_rx_buffer = xmalloc(NL_RX_SIZE);
}
}
static void
nl_send(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_sync_seq;
if (sendto(nl_sync_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;
req.g.rtgen_family = BIRD_PF;
nl_send(&req.nh);
}
static struct nlmsghdr *
nl_get_reply(void)
{
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_sync_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;
if (h->nlmsg_seq != nl_sync_seq)
{
log(L_WARN "nl_get_reply: Ignoring out of sequence netlink packet (%x != %x)",
h->nlmsg_seq, nl_sync_seq);
continue;
}
nl_last_hdr = NLMSG_NEXT(h, nl_last_size);
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 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(L_WARN "Netlink: %s", strerror(ec));
return ec;
}
static struct nlmsghdr *
nl_get_scan(void)
{
struct nlmsghdr *h = nl_get_reply();
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(pkt);
for(;;)
{
h = nl_get_reply();
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;
}
static void
nl_add_attr_u32(struct nlmsghdr *h, unsigned maxsize, int code, u32 data)
{
unsigned len = RTA_LENGTH(4);
struct rtattr *a;
if (NLMSG_ALIGN(h->nlmsg_len) + len > maxsize)
bug("nl_add_attr32: packet buffer overflow");
a = (struct rtattr *)((char *)h + NLMSG_ALIGN(h->nlmsg_len));
a->rta_type = code;
a->rta_len = len;
memcpy(RTA_DATA(a), &data, 4);
h->nlmsg_len = NLMSG_ALIGN(h->nlmsg_len) + len;
}
static void
nl_add_attr_ipa(struct nlmsghdr *h, unsigned maxsize, int code, ip_addr ipa)
{
unsigned len = RTA_LENGTH(sizeof(ipa));
struct rtattr *a;
if (NLMSG_ALIGN(h->nlmsg_len) + len > maxsize)
bug("nl_add_attr_ipa: packet buffer overflow");
a = (struct rtattr *)((char *)h + NLMSG_ALIGN(h->nlmsg_len));
a->rta_type = code;
a->rta_len = len;
ipa_hton(ipa);
memcpy(RTA_DATA(a), &ipa, sizeof(ipa));
h->nlmsg_len = NLMSG_ALIGN(h->nlmsg_len) + len;
}
/*
* Scanning of interfaces
*/
static void
nl_parse_link(struct nlmsghdr *h, int scan)
{
struct ifinfomsg *i;
struct rtattr *a[IFLA_STATS+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)
{
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_ADMIN_DOWN;
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_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;
}
#ifdef IPV6
if (i->ifa_scope == RT_SCOPE_LINK)
return;
#endif
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 ||
i->ifa_prefixlen == BITS_PER_IP_ADDRESS - 1)
{
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)
{
ifa.flags |= IA_UNNUMBERED;
memcpy(&ifa.opposite, RTA_DATA(a[IFA_ADDRESS]), sizeof(ifa.opposite));
ipa_ntoh(ifa.opposite);
ifa.prefix = ifa.brd = ifa.opposite;
}
else
{
ip_addr netmask = ipa_mkmask(ifa.pxlen);
ip_addr xbrd;
ifa.prefix = ipa_and(ifa.ip, netmask);
ifa.brd = ipa_or(ifa.ip, ipa_not(netmask));
#ifndef IPV6
if (i->ifa_prefixlen == BITS_PER_IP_ADDRESS - 2)
ifa.opposite = ipa_opposite(ifa.ip);
if ((ifi->flags & IF_BROADCAST) && a[IFA_BROADCAST])
{
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
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)
{
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
#if 0
&& a->cast != RTC_ANYCAST
#endif
)
return 0;
if (a->source == RTS_DEVICE) /* Kernel takes care of device routes itself */
return 0;
switch (a->dest)
{
case RTD_ROUTER:
case RTD_DEVICE:
case RTD_BLACKHOLE:
case RTD_UNREACHABLE:
case RTD_PROHIBIT:
break;
default:
return 0;
}
return 1;
}
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[128];
} 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_REPLACE : 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);
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;
default:
bug("krt_capable inconsistent with nl_send_route");
}
nl_exchange(&r.h);
}
void
krt_set_notify(struct krt_proto *p, net *n, rte *new, rte *old)
{
if (old && new)
{
/*
* We should check whether priority and TOS is identical as well,
* but we don't use these and default value is always equal to default value. :-)
*/
nl_send_route(p, new, 1);
}
else
{
if (old)
{
if (!old->attrs->iface || (old->attrs->iface->flags & IF_UP))
nl_send_route(p, old, 0);
/* else the kernel has already flushed it */
}
if (new)
nl_send_route(p, new, 1);
}
}
struct iface *
krt_temp_iface(struct krt_proto *p, unsigned index)
{
struct iface *i, *j;
WALK_LIST(i, p->scan.temp_ifs)
if (i->index == index)
return i;
i = mb_allocz(p->p.pool, sizeof(struct iface));
if (j = if_find_by_index(index))
strcpy(i->name, j->name);
else
strcpy(i->name, "?");
i->index = index;
add_tail(&p->scan.temp_ifs, &i->n);
return i;
}
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;
rta ra;
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 "nl_parse_route: Malformed message received");
return;
}
p = nl_table_map[i->rtm_table]; /* Do we know this table? */
if (!p)
return;
#ifdef IPV6
if (a[RTA_IIF])
{
DBG("KRT: Ignoring route with IIF set\n");
return;
}
#else
if (i->rtm_tos != 0) /* We don't support TOS */
{
DBG("KRT: Ignoring route with TOS %02x\n", i->rtm_tos);
return;
}
#endif
if (scan && !new)
{
DBG("KRT: Ignoring route deletion\n");
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("Got %I/%d, type=%d, oif=%d, table=%d, proto=%s\n", dst, i->rtm_dst_len, i->rtm_type, oif, i->rtm_table, p->p.name);
switch (i->rtm_protocol)
{
case RTPROT_REDIRECT:
src = KRT_SRC_REDIRECT;
break;
case RTPROT_KERNEL:
DBG("Route originated in kernel, ignoring\n");
return;
case RTPROT_BIRD:
if (!scan)
{
DBG("Echo of our own route, ignoring\n");
return;
}
src = KRT_SRC_BIRD;
break;
default:
src = KRT_SRC_ALIEN;
}
net = net_get(p->p.table, dst, i->rtm_dst_len);
ra.proto = &p->p;
ra.source = RTS_INHERIT;
ra.scope = SCOPE_UNIVERSE;
ra.cast = RTC_UNICAST;
ra.flags = ra.aflags = 0;
ra.from = IPA_NONE;
ra.gw = IPA_NONE;
ra.iface = NULL;
ra.eattrs = NULL;
switch (i->rtm_type)
{
case RTN_UNICAST:
if (oif == ~0U)
{
log(L_ERR "KRT: Mysterious route with no OIF (%I/%d)", net->n.prefix, net->n.pxlen);
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_find(&p->p, &ra.gw, 0);
if (ng && ng->scope)
ra.iface = ng->iface;
else
/* FIXME: Remove this warning? Handle it somehow... */
log(L_WARN "Kernel told us to use non-neighbor %I for %I/%d", ra.gw, net->n.prefix, net->n.pxlen);
}
else
{
ra.dest = RTD_DEVICE;
ra.iface = krt_temp_iface(p, oif);
}
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:
DBG("KRT: Ignoring route with type=%d\n", i->rtm_type);
return;
}
if (i->rtm_scope != RT_SCOPE_UNIVERSE)
{
DBG("KRT: Ignoring route with scope=%d\n", i->rtm_scope);
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) /* 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)
{
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;
nl_last_hdr = NULL; /* Discard packets accidentally remaining in the rxbuf */
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)
{
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;
#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, int last)
{
}
void
krt_if_start(struct kif_proto *p)
{
nl_open();
nl_open_async();
}
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