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cce6ba4daa
bird/sysdep/linux/netlink.c
Ondrej Zajicek (work) 943478b00f Basic VRF support 
Add basic VRF (virtual routing and forwarding) support. Protocols can be
associated with VRFs, such protocols will be restricted to interfaces
assigned to the VRF (as reported by Linux kernel) and will use sockets
bound to the VRF. E.g., different multihop BGP instances can use diffent
kernel routing tables to handle BGP TCP connections.

The VRF support is preliminary, currently there are several limitations:

- Recent Linux kernels (4.11) do not handle correctly sockets bound
to interaces that are part of VRF, so most protocols other than multihop
BGP do not work. This will be fixed by future kernel versions.

- Neighbor cache ignores VRFs. Breaks config with the same prefix on
local interfaces in different VRFs. Not much problem as single hop
protocols do not work anyways.

- Olock code ignores VRFs. Breaks config with multiple BGP peers with the
same IP address in different VRFs.

- Incoming BGP connections are not dispatched according to VRFs.
Breaks config with multiple BGP peers with the same IP address in
different VRFs. Perhaps we would need some kernel API to read VRF of
incoming connection? Or probably use multiple listening sockets in
int-new branch.

- We should handle master VRF interface up/down events and perhaps
disable associated protocols when VRF goes down. Or at least disable
associated interfaces.

- Also we should check if the master iface is really VRF iface and
not some other kind of master iface.

- BFD session request dispatch should be aware of VRFs.

- Perhaps kernel protocol should read default kernel table ID from VRF
iface so it is not necessary to configure it.

- Perhaps we should have per-VRF default table.
2017-09-06 17:38:48 +02:00

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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 <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/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 IFA_FLAGS
#define IFA_FLAGS 8
#endif
#ifndef IFF_LOWER_UP
#define IFF_LOWER_UP 0x10000
#endif
#ifndef RTA_TABLE
#define RTA_TABLE 15
#endif
#ifdef IPV6
#define krt_ecmp6(X) 1
#else
#define krt_ecmp6(X) 0
#endif
/*
* Structure nl_parse_state keeps state of received route processing. Ideally,
* we could just independently parse received Netlink messages and immediately
* propagate received routes to the rest of BIRD, but older Linux kernel (before
* version 4.11) represents and announces IPv6 ECMP routes not as one route with
* multiple next hops (like RTA_MULTIPATH in IPv4 ECMP), but as a sequence of
* routes with the same prefix. More recent kernels work as with IPv4.
*
* Therefore, BIRD keeps currently processed route in nl_parse_state structure
* and postpones its propagation until we expect it to be final; i.e., when
* non-matching route is received or when the scan ends. When another matching
* route is received, it is merged with the already processed route to form an
* ECMP route. Note that merging is done only for IPv6 (merge == 1), but the
* postponing is done in both cases (for simplicity). All IPv4 routes or IPv6
* routes with RTA_MULTIPATH set are just considered non-matching.
*
* This is ignored for asynchronous notifications (every notification is handled
* as a separate route). It is not an issue for our routes, as we ignore such
* notifications anyways. But importing alien IPv6 ECMP routes does not work
* properly with older kernels.
*
* Whatever the kernel version is, IPv6 ECMP routes are sent as multiple routes
* for the same prefix.
*/
struct nl_parse_state
{
struct linpool *pool;
int scan;
int merge;
net *net;
rta *attrs;
struct krt_proto *proto;
s8 new;
s8 krt_src;
u8 krt_type;
u8 krt_proto;
u32 krt_metric;
};
/*
* 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
#define NL_OP_DELETE 0
#define NL_OP_ADD (NLM_F_CREATE|NLM_F_EXCL)
#define NL_OP_REPLACE (NLM_F_CREATE|NLM_F_REPLACE)
#define NL_OP_APPEND (NLM_F_CREATE|NLM_F_APPEND)
static linpool *nl_linpool;
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 = {
.msg_name = &sa,
.msg_namelen = sizeof(sa),
.msg_iov = &iov,
.msg_iovlen = 1,
};
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, int ignore_esrch)
{
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 && !(ignore_esrch && (ec == ESRCH)))
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, 0);
return NULL;
}
return h;
}
static int
nl_exchange(struct nlmsghdr *pkt, int ignore_esrch)
{
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, ignore_esrch) ? -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_MASTER] = { 1, 1, sizeof(u32) },
[IFLA_WIRELESS] = { 1, 0, 0 },
};
#define BIRD_IFA_MAX (IFA_FLAGS+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) },
[IFA_FLAGS] = { 1, 1, sizeof(u32) },
};
#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) },
[IFA_FLAGS] = { 1, 1, sizeof(u32) },
};
#endif
#define BIRD_RTA_MAX (RTA_TABLE+1)
#ifndef IPV6
static struct nl_want_attrs mpnh_attr_want4[BIRD_RTA_MAX] = {
[RTA_GATEWAY] = { 1, 1, sizeof(ip4_addr) },
};
#else
static struct nl_want_attrs mpnh_attr_want6[BIRD_RTA_MAX] = {
[RTA_GATEWAY] = { 1, 1, sizeof(ip6_addr) },
};
#endif
#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_MULTIPATH] = { 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, int af)
{
/* 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;
unsigned 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);
switch (af)
{
#ifndef IPV6
case AF_INET:
if (!nl_parse_attrs(RTNH_DATA(nh), mpnh_attr_want4, a, sizeof(a)))
return NULL;
break;
#else
case AF_INET6:
if (!nl_parse_attrs(RTNH_DATA(nh), mpnh_attr_want6, a, sizeof(a)))
return NULL;
break;
#endif
default:
return NULL;
}
if (a[RTA_GATEWAY])
{
memcpy(&rv->gw, RTA_DATA(a[RTA_GATEWAY]), sizeof(rv->gw));
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, master = 0;
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]);
if (a[IFLA_MASTER])
master = rta_get_u32(a[IFLA_MASTER]);
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;
f.master_index = master;
f.master = if_find_by_index(master);
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;
u32 ifa_flags;
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;
}
if (a[IFA_FLAGS])
ifa_flags = rta_get_u32(a[IFA_FLAGS]);
else
ifa_flags = i->ifa_flags;
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 (ifa_flags & IFA_F_SECONDARY)
ifa.flags |= IA_SECONDARY;
#ifdef IPV6
/* Ignore tentative addresses silently */
if (ifa_flags & IFA_F_TENTATIVE)
return;
#endif
/* 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);
/* Re-resolve master interface for slaves */
struct iface *i;
WALK_LIST(i, iface_list)
if (i->master_index)
{
struct iface f = {
.flags = i->flags,
.mtu = i->mtu,
.index = i->index,
.master_index = i->master_index,
.master = if_find_by_index(i->master_index)
};
if (f.master != i->master)
{
memcpy(f.name, i->name, sizeof(f.name));
if_update(&f);
}
}
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 op, int dest, ip_addr gw, struct iface *iface)
{
eattr *ea;
net *net = e->net;
rta *a = e->attrs;
u32 priority = 0;
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,op=%x)\n", net->n.prefix, net->n.pxlen, op);
bzero(&r.h, sizeof(r.h));
bzero(&r.r, sizeof(r.r));
r.h.nlmsg_type = op ? RTM_NEWROUTE : RTM_DELROUTE;
r.h.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
r.h.nlmsg_flags = op | NLM_F_REQUEST | NLM_F_ACK;
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_NOWHERE;
nl_add_attr_ipa(&r.h, sizeof(r), RTA_DST, net->n.prefix);
/*
* Strange behavior for RTM_DELROUTE:
* 1) rtm_family is ignored in IPv6, works for IPv4
* 2) not setting RTA_PRIORITY is different from setting default value (on IPv6)
* 3) not setting RTA_PRIORITY is equivalent to setting 0, which is wildcard
*/
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));
if (a->source == RTS_DUMMY)
priority = e->u.krt.metric;
else if (KRT_CF->sys.metric)
priority = KRT_CF->sys.metric;
else if ((op != NL_OP_DELETE) && (ea = ea_find(eattrs, EA_KRT_METRIC)))
priority = ea->u.data;
if (priority)
nl_add_attr_u32(&r.h, sizeof(r), RTA_PRIORITY, priority);
/* For route delete, we do not specify remaining route attributes */
if (op == NL_OP_DELETE)
goto dest;
/* Default scope is LINK for device routes, UNIVERSE otherwise */
if (ea = ea_find(eattrs, EA_KRT_SCOPE))
r.r.rtm_scope = ea->u.data;
else
r.r.rtm_scope = (dest == RTD_DEVICE) ? RT_SCOPE_LINK : RT_SCOPE_UNIVERSE;
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);
dest:
/* a->iface != NULL checked in krt_capable() for router and device routes */
switch (dest)
{
case RTD_ROUTER:
r.r.rtm_type = RTN_UNICAST;
nl_add_attr_u32(&r.h, sizeof(r), RTA_OIF, iface->index);
nl_add_attr_ipa(&r.h, sizeof(r), RTA_GATEWAY, gw);
break;
case RTD_DEVICE:
r.r.rtm_type = RTN_UNICAST;
nl_add_attr_u32(&r.h, sizeof(r), RTA_OIF, 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;
case RTD_NONE:
break;
default:
bug("krt_capable inconsistent with nl_send_route");
}
/* Ignore missing for DELETE */
return nl_exchange(&r.h, (op == NL_OP_DELETE));
}
static inline int
nl_add_rte(struct krt_proto *p, rte *e, struct ea_list *eattrs)
{
rta *a = e->attrs;
int err = 0;
if (krt_ecmp6(p) && (a->dest == RTD_MULTIPATH))
{
struct mpnh *nh = a->nexthops;
err = nl_send_route(p, e, eattrs, NL_OP_ADD, RTD_ROUTER, nh->gw, nh->iface);
if (err < 0)
return err;
for (nh = nh->next; nh; nh = nh->next)
err += nl_send_route(p, e, eattrs, NL_OP_APPEND, RTD_ROUTER, nh->gw, nh->iface);
return err;
}
return nl_send_route(p, e, eattrs, NL_OP_ADD, a->dest, a->gw, a->iface);
}
static inline int
nl_delete_rte(struct krt_proto *p, rte *e, struct ea_list *eattrs)
{
int err = 0;
/* For IPv6, we just repeatedly request DELETE until we get error */
do
err = nl_send_route(p, e, eattrs, NL_OP_DELETE, RTD_NONE, IPA_NONE, NULL);
while (krt_ecmp6(p) && !err);
return err;
}
void
krt_replace_rte(struct krt_proto *p, net *n, rte *new, rte *old, struct ea_list *eattrs)
{
int err = 0;
/*
* We could use NL_OP_REPLACE, but route replace on Linux has some problems:
*
* 1) Does not check for matching rtm_protocol
* 2) Has broken semantics for IPv6 ECMP
* 3) Crashes some kernel version when used for IPv6 ECMP
*
* So we use NL_OP_DELETE and then NL_OP_ADD. We also do not trust the old
* route value, so we do not try to optimize IPv6 ECMP reconfigurations.
*/
if (old)
nl_delete_rte(p, old, eattrs);
if (new)
err = nl_add_rte(p, new, eattrs);
if (err < 0)
n->n.flags |= KRF_SYNC_ERROR;
else
n->n.flags &= ~KRF_SYNC_ERROR;
}
static inline struct mpnh *
nl_alloc_mpnh(struct nl_parse_state *s, ip_addr gw, struct iface *iface, byte weight)
{
struct mpnh *nh = lp_alloc(s->pool, sizeof(struct mpnh));
nh->gw = gw;
nh->iface = iface;
nh->next = NULL;
nh->weight = weight;
return nh;
}
static int
nl_mergable_route(struct nl_parse_state *s, net *net, struct krt_proto *p, uint priority, uint krt_type)
{
/* Route merging must be active */
if (!s->merge)
return 0;
/* Saved and new route must have same network, proto/table, and priority */
if ((s->net != net) || (s->proto != p) || (s->krt_metric != priority))
return 0;
/* Both must be regular unicast routes */
if ((s->krt_type != RTN_UNICAST) || (krt_type != RTN_UNICAST))
return 0;
return 1;
}
static void
nl_announce_route(struct nl_parse_state *s)
{
rte *e = rte_get_temp(s->attrs);
e->net = s->net;
e->u.krt.src = s->krt_src;
e->u.krt.proto = s->krt_proto;
e->u.krt.seen = 0;
e->u.krt.best = 0;
e->u.krt.metric = s->krt_metric;
if (s->scan)
krt_got_route(s->proto, e);
else
krt_got_route_async(s->proto, e, s->new);
s->net = NULL;
s->attrs = NULL;
s->proto = NULL;
lp_flush(s->pool);
}
static inline void
nl_parse_begin(struct nl_parse_state *s, int scan, int merge)
{
memset(s, 0, sizeof (struct nl_parse_state));
s->pool = nl_linpool;
s->scan = scan;
s->merge = merge;
}
static inline void
nl_parse_end(struct nl_parse_state *s)
{
if (s->net)
nl_announce_route(s);
}
#define SKIP(ARG...) do { DBG("KRT: Ignoring route - " ARG); return; } while(0)
static void
nl_parse_route(struct nl_parse_state *s, struct nlmsghdr *h)
{
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;
u32 priority = 0;
u32 def_scope = RT_SCOPE_UNIVERSE;
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 (s->scan && !new)
SKIP("RTM_DELROUTE in scan\n");
if (a[RTA_PRIORITY])
priority = rta_get_u32(a[RTA_PRIORITY]);
int c = ipa_classify_net(dst);
if ((c < 0) || !(c & IADDR_HOST) || ((c & IADDR_SCOPE_MASK) <= SCOPE_LINK))
SKIP("strange class/scope\n");
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 (!s->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);
if (s->net && !nl_mergable_route(s, net, p, priority, i->rtm_type))
nl_announce_route(s);
rta *ra = lp_allocz(s->pool, sizeof(rta));
ra->src = p->p.main_source;
ra->source = RTS_INHERIT;
ra->scope = SCOPE_UNIVERSE;
ra->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], i->rtm_family);
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;
def_scope = RT_SCOPE_LINK;
}
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;
}
if (i->rtm_scope != def_scope)
{
ea_list *ea = lp_alloc(s->pool, 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_SCOPE;
ea->attrs[0].flags = 0;
ea->attrs[0].type = EAF_TYPE_INT;
ea->attrs[0].u.data = i->rtm_scope;
}
if (a[RTA_PREFSRC])
{
ip_addr ps;
memcpy(&ps, RTA_DATA(a[RTA_PREFSRC]), sizeof(ps));
ipa_ntoh(ps);
ea_list *ea = lp_alloc(s->pool, 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 = lp_alloc(s->pool, 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 = lp_alloc(s->pool, 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 = lp_alloc(s->pool, 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;
}
}
/*
* Ideally, now we would send the received route to the rest of kernel code.
* But IPv6 ECMP routes before 4.11 are sent as a sequence of routes, so we
* postpone it and merge next hops until the end of the sequence. Note that
* proper multipath updates are rejected by nl_mergable_route(), so it is
* always the first case for them.
*/
if (!s->net)
{
/* Store the new route */
s->net = net;
s->attrs = ra;
s->proto = p;
s->new = new;
s->krt_src = src;
s->krt_type = i->rtm_type;
s->krt_proto = i->rtm_protocol;
s->krt_metric = priority;
}
else
{
/* Merge next hops with the stored route */
rta *a = s->attrs;
if (a->dest != RTD_MULTIPATH)
{
a->dest = RTD_MULTIPATH;
a->nexthops = nl_alloc_mpnh(s, a->gw, a->iface, 0);
}
mpnh_insert(&a->nexthops, nl_alloc_mpnh(s, ra->gw, ra->iface, 0));
}
}
void
krt_do_scan(struct krt_proto *p UNUSED) /* CONFIG_ALL_TABLES_AT_ONCE => p is NULL */
{
struct nlmsghdr *h;
struct nl_parse_state s;
nl_parse_begin(&s, 1, krt_ecmp6(p));
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(&s, h);
else
log(L_DEBUG "nl_scan_fire: Unknown packet received (type=%d)", h->nlmsg_type);
nl_parse_end(&s);
}
/*
* 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)
{
struct nl_parse_state s;
switch (h->nlmsg_type)
{
case RTM_NEWROUTE:
case RTM_DELROUTE:
DBG("KRT: Received async route notification (%d)\n", h->nlmsg_type);
nl_parse_begin(&s, 0, 0);
nl_parse_route(&s, h);
nl_parse_end(&s);
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, uint size UNUSED)
{
struct iovec iov = { nl_async_rx_buffer, NL_RX_SIZE };
struct sockaddr_nl sa;
struct msghdr m = {
.msg_name = &sa,
.msg_namelen = sizeof(sa),
.msg_iov = &iov,
.msg_iovlen = 1,
};
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.
*/
log(L_WARN "Kernel dropped some netlink messages, will resync on next scan.");
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_async_err_hook(sock *sk, int e UNUSED)
{
nl_async_hook(sk, 0);
}
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->err_hook = nl_async_err_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)
{
nl_linpool = lp_new(krt_pool, 4080);
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) && (n->sys.metric == o->sys.metric);
}
void
krt_sys_init_config(struct krt_config *cf)
{
cf->sys.table_id = RT_TABLE_MAIN;
cf->sys.metric = 0;
}
void
krt_sys_copy_config(struct krt_config *d, struct krt_config *s)
{
d->sys.table_id = s->sys.table_id;
d->sys.metric = s->sys.metric;
}
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_SCOPE:
bsprintf(buf, "scope");
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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