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bird/sysdep/linux/netlink.c
Ondrej Zajicek (work) ef614f2984 Netlink: Minor cleanup
2022-02-08 22:21:08 +01:00

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/*
* BIRD -- Linux Netlink Interface
*
* (c) 1999--2000 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include <alloca.h>
#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 "sysdep/unix/unix.h"
#include "sysdep/unix/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>
#ifdef HAVE_MPLS_KERNEL
#include <linux/lwtunnel.h>
#endif
#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
#ifndef RTA_VIA
#define RTA_VIA 18
#endif
#ifndef RTA_NEWDST
#define RTA_NEWDST 19
#endif
#ifndef RTA_ENCAP_TYPE
#define RTA_ENCAP_TYPE 21
#endif
#ifndef RTA_ENCAP
#define RTA_ENCAP 22
#endif
#ifndef NETLINK_GET_STRICT_CHK
#define NETLINK_GET_STRICT_CHK 12
#endif
#define krt_ipv4(p) ((p)->af == AF_INET)
#define krt_ecmp6(p) ((p)->af == AF_INET6)
const int rt_default_ecmp = 16;
/*
* 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;
u32 rta_flow; /* Used during parsing */
};
/*
* 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 32768
#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 = (u32) (current_time() TO_S); /* Or perhaps random_u32() ? */
nl->rx_buffer = xmalloc(NL_RX_SIZE);
nl->last_hdr = NULL;
nl->last_size = 0;
}
}
static void
nl_set_strict_dump(struct nl_sock *nl UNUSED, int strict UNUSED)
{
/*
* Strict checking is not necessary, it improves behavior on newer kernels.
* If it is not available (missing SOL_NETLINK compile-time, or ENOPROTOOPT
* run-time), we can just ignore it.
*/
#ifdef SOL_NETLINK
setsockopt(nl->fd, SOL_NETLINK, NETLINK_GET_STRICT_CHK, &strict, sizeof(strict));
#endif
}
static void
nl_set_rcvbuf(int fd, uint val)
{
if (setsockopt(fd, SOL_SOCKET, SO_RCVBUFFORCE, &val, sizeof(val)) < 0)
log(L_WARN "KRT: Cannot set netlink rx buffer size to %u: %m", val);
}
static uint
nl_cfg_rx_buffer_size(struct config *cfg)
{
uint bufsize = 0;
struct proto_config *pc;
WALK_LIST(pc, cfg->protos)
if ((pc->protocol == &proto_unix_kernel) && !pc->disabled)
bufsize = MAX(bufsize, ((struct krt_config *) pc)->sys.netlink_rx_buffer);
return bufsize;
}
static void
nl_open(void)
{
nl_open_sock(&nl_scan);
nl_open_sock(&nl_req);
nl_set_strict_dump(&nl_scan, 1);
}
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);
nh->nlmsg_len = NLMSG_ALIGN(nh->nlmsg_len);
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_link(void)
{
struct {
struct nlmsghdr nh;
struct ifinfomsg ifi;
} req = {
.nh.nlmsg_type = RTM_GETLINK,
.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP,
.nh.nlmsg_seq = ++(nl_scan.seq),
.ifi.ifi_family = AF_UNSPEC,
};
send(nl_scan.fd, &req, sizeof(req), 0);
nl_scan.last_hdr = NULL;
}
static void
nl_request_dump_addr(int af)
{
struct {
struct nlmsghdr nh;
struct ifaddrmsg ifa;
} req = {
.nh.nlmsg_type = RTM_GETADDR,
.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg)),
.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP,
.nh.nlmsg_seq = ++(nl_scan.seq),
.ifa.ifa_family = af,
};
send(nl_scan.fd, &req, sizeof(req), 0);
nl_scan.last_hdr = NULL;
}
static void
nl_request_dump_route(int af)
{
struct {
struct nlmsghdr nh;
struct rtmsg rtm;
} req = {
.nh.nlmsg_type = RTM_GETROUTE,
.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg)),
.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP,
.nh.nlmsg_seq = ++(nl_scan.seq),
.rtm.rtm_family = af,
};
send(nl_scan.fd, &req, sizeof(req), 0);
nl_scan.last_hdr = NULL;
}
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)
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) },
};
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) },
};
#define BIRD_RTA_MAX (RTA_ENCAP+1)
static struct nl_want_attrs nexthop_attr_want4[BIRD_RTA_MAX] = {
[RTA_GATEWAY] = { 1, 1, sizeof(ip4_addr) },
[RTA_VIA] = { 1, 0, 0 },
[RTA_FLOW] = { 1, 1, sizeof(u32) },
[RTA_ENCAP_TYPE]= { 1, 1, sizeof(u16) },
[RTA_ENCAP] = { 1, 0, 0 },
};
static struct nl_want_attrs nexthop_attr_want6[BIRD_RTA_MAX] = {
[RTA_GATEWAY] = { 1, 1, sizeof(ip6_addr) },
[RTA_VIA] = { 1, 0, 0 },
[RTA_FLOW] = { 1, 1, sizeof(u32) },
[RTA_ENCAP_TYPE]= { 1, 1, sizeof(u16) },
[RTA_ENCAP] = { 1, 0, 0 },
};
#ifdef HAVE_MPLS_KERNEL
static struct nl_want_attrs nexthop_attr_want_mpls[BIRD_RTA_MAX] = {
[RTA_VIA] = { 1, 0, 0 },
[RTA_NEWDST] = { 1, 0, 0 },
};
static struct nl_want_attrs encap_mpls_want[BIRD_RTA_MAX] = {
[RTA_DST] = { 1, 0, 0 },
};
#endif
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) },
[RTA_VIA] = { 1, 0, 0 },
[RTA_ENCAP_TYPE]= { 1, 1, sizeof(u16) },
[RTA_ENCAP] = { 1, 0, 0 },
};
static struct nl_want_attrs rtm_attr_want6[BIRD_RTA_MAX] = {
[RTA_DST] = { 1, 1, sizeof(ip6_addr) },
[RTA_SRC] = { 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) },
[RTA_VIA] = { 1, 0, 0 },
[RTA_ENCAP_TYPE]= { 1, 1, sizeof(u16) },
[RTA_ENCAP] = { 1, 0, 0 },
};
#ifdef HAVE_MPLS_KERNEL
static struct nl_want_attrs rtm_attr_want_mpls[BIRD_RTA_MAX] = {
[RTA_DST] = { 1, 1, sizeof(u32) },
[RTA_IIF] = { 1, 1, sizeof(u32) },
[RTA_OIF] = { 1, 1, sizeof(u32) },
[RTA_PRIORITY] = { 1, 1, sizeof(u32) },
[RTA_METRICS] = { 1, 0, 0 },
[RTA_MULTIPATH] = { 1, 0, 0 },
[RTA_FLOW] = { 1, 1, sizeof(u32) },
[RTA_TABLE] = { 1, 1, sizeof(u32) },
[RTA_VIA] = { 1, 0, 0 },
[RTA_NEWDST] = { 1, 0, 0 },
};
#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 attribute 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 u16 rta_get_u16(struct rtattr *a)
{ return *(u16 *) RTA_DATA(a); }
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)); }
static inline ip_addr rta_get_ipa(struct rtattr *a)
{
if (RTA_PAYLOAD(a) == sizeof(ip4_addr))
return ipa_from_ip4(rta_get_ip4(a));
else
return ipa_from_ip6(rta_get_ip6(a));
}
#ifdef HAVE_MPLS_KERNEL
static inline ip_addr rta_get_via(struct rtattr *a)
{
struct rtvia *v = RTA_DATA(a);
switch(v->rtvia_family) {
case AF_INET: return ipa_from_ip4(ip4_ntoh(*(ip4_addr *) v->rtvia_addr));
case AF_INET6: return ipa_from_ip6(ip6_ntoh(*(ip6_addr *) v->rtvia_addr));
}
return IPA_NONE;
}
static u32 rta_mpls_stack[MPLS_MAX_LABEL_STACK];
static inline int rta_get_mpls(struct rtattr *a, u32 *stack)
{
if (!a)
return 0;
if (RTA_PAYLOAD(a) % 4)
log(L_WARN "KRT: Strange length of received MPLS stack: %u", RTA_PAYLOAD(a));
int labels = mpls_get(RTA_DATA(a), RTA_PAYLOAD(a) & ~0x3, stack);
if (labels < 0)
{
log(L_WARN "KRT: Too long MPLS stack received, ignoring");
labels = 0;
}
return labels;
}
#endif
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 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 void
nl_add_attr_u16(struct nlmsghdr *h, uint bufsize, int code, u16 data)
{
nl_add_attr(h, bufsize, code, &data, 2);
}
static inline void
nl_add_attr_u32(struct nlmsghdr *h, uint bufsize, int code, u32 data)
{
nl_add_attr(h, bufsize, code, &data, 4);
}
static inline void
nl_add_attr_ip4(struct nlmsghdr *h, uint bufsize, int code, ip4_addr ip4)
{
ip4 = ip4_hton(ip4);
nl_add_attr(h, bufsize, code, &ip4, sizeof(ip4));
}
static inline void
nl_add_attr_ip6(struct nlmsghdr *h, uint bufsize, int code, ip6_addr ip6)
{
ip6 = ip6_hton(ip6);
nl_add_attr(h, bufsize, code, &ip6, sizeof(ip6));
}
static inline void
nl_add_attr_ipa(struct nlmsghdr *h, uint bufsize, int code, ip_addr ipa)
{
if (ipa_is_ip4(ipa))
nl_add_attr_ip4(h, bufsize, code, ipa_to_ip4(ipa));
else
nl_add_attr_ip6(h, bufsize, code, ipa_to_ip6(ipa));
}
#ifdef HAVE_MPLS_KERNEL
static inline void
nl_add_attr_mpls(struct nlmsghdr *h, uint bufsize, int code, int len, u32 *stack)
{
char buf[len*4];
mpls_put(buf, len, stack);
nl_add_attr(h, bufsize, code, buf, len*4);
}
static inline void
nl_add_attr_mpls_encap(struct nlmsghdr *h, uint bufsize, int len, u32 *stack)
{
nl_add_attr_u16(h, bufsize, RTA_ENCAP_TYPE, LWTUNNEL_ENCAP_MPLS);
struct rtattr *nest = nl_open_attr(h, bufsize, RTA_ENCAP);
nl_add_attr_mpls(h, bufsize, RTA_DST, len, stack);
nl_close_attr(h, nest);
}
static inline void
nl_add_attr_via(struct nlmsghdr *h, uint bufsize, ip_addr ipa)
{
struct rtvia *via = alloca(sizeof(struct rtvia) + 16);
if (ipa_is_ip4(ipa))
{
via->rtvia_family = AF_INET;
put_ip4(via->rtvia_addr, ipa_to_ip4(ipa));
nl_add_attr(h, bufsize, RTA_VIA, via, sizeof(struct rtvia) + 4);
}
else
{
via->rtvia_family = AF_INET6;
put_ip6(via->rtvia_addr, ipa_to_ip6(ipa));
nl_add_attr(h, bufsize, RTA_VIA, via, sizeof(struct rtvia) + 16);
}
}
#endif
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 inline void
nl_add_nexthop(struct nlmsghdr *h, uint bufsize, struct nexthop *nh, int af UNUSED)
{
#ifdef HAVE_MPLS_KERNEL
if (nh->labels > 0)
if (af == AF_MPLS)
nl_add_attr_mpls(h, bufsize, RTA_NEWDST, nh->labels, nh->label);
else
nl_add_attr_mpls_encap(h, bufsize, nh->labels, nh->label);
if (ipa_nonzero(nh->gw))
{
if (af == (ipa_is_ip4(nh->gw) ? AF_INET : AF_INET6))
nl_add_attr_ipa(h, bufsize, RTA_GATEWAY, nh->gw);
else
nl_add_attr_via(h, bufsize, nh->gw);
}
#else
if (ipa_nonzero(nh->gw))
nl_add_attr_ipa(h, bufsize, RTA_GATEWAY, nh->gw);
#endif
}
static void
nl_add_multipath(struct nlmsghdr *h, uint bufsize, struct nexthop *nh, int af, ea_list *eattrs)
{
struct rtattr *a = nl_open_attr(h, bufsize, RTA_MULTIPATH);
eattr *flow = ea_find(eattrs, EA_KRT_REALM);
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_nexthop(h, bufsize, nh, af);
if (nh->flags & RNF_ONLINK)
rtnh->rtnh_flags |= RTNH_F_ONLINK;
/* Our KRT_REALM is per-route, but kernel RTA_FLOW is per-nexthop.
Therefore, we need to attach the same attribute to each nexthop. */
if (flow)
nl_add_attr_u32(h, bufsize, RTA_FLOW, flow->u.data);
nl_close_nexthop(h, rtnh);
}
nl_close_attr(h, a);
}
static struct nexthop *
nl_parse_multipath(struct nl_parse_state *s, struct krt_proto *p, const net_addr *n, struct rtattr *ra, int af, int krt_src)
{
struct rtattr *a[BIRD_RTA_MAX];
struct rtnexthop *nh = RTA_DATA(ra);
struct nexthop *rv, *first, **last;
unsigned len = RTA_PAYLOAD(ra);
first = NULL;
last = &first;
while (len)
{
/* Use RTNH_OK(nh,len) ?? */
if ((len < sizeof(*nh)) || (len < nh->rtnh_len))
goto err;
if ((nh->rtnh_flags & RTNH_F_DEAD) && (krt_src != KRT_SRC_BIRD))
goto next;
*last = rv = lp_allocz(s->pool, NEXTHOP_MAX_SIZE);
last = &(rv->next);
rv->weight = nh->rtnh_hops;
rv->iface = if_find_by_index(nh->rtnh_ifindex);
if (!rv->iface)
{
log(L_ERR "KRT: Received route %N with unknown ifindex %u", n, nh->rtnh_ifindex);
return NULL;
}
/* Nonexistent RTNH_PAYLOAD ?? */
nl_attr_len = nh->rtnh_len - RTNH_LENGTH(0);
switch (af)
{
case AF_INET:
if (!nl_parse_attrs(RTNH_DATA(nh), nexthop_attr_want4, a, sizeof(a)))
goto err;
break;
case AF_INET6:
if (!nl_parse_attrs(RTNH_DATA(nh), nexthop_attr_want6, a, sizeof(a)))
goto err;
break;
#ifdef HAVE_MPLS_KERNEL
case AF_MPLS:
if (!nl_parse_attrs(RTNH_DATA(nh), nexthop_attr_want_mpls, a, sizeof(a)))
goto err;
if (a[RTA_NEWDST])
rv->labels = rta_get_mpls(a[RTA_NEWDST], rv->label);
break;
#endif
default:
goto err;
}
if (a[RTA_GATEWAY])
rv->gw = rta_get_ipa(a[RTA_GATEWAY]);
if (a[RTA_FLOW])
s->rta_flow = rta_get_u32(a[RTA_FLOW]);
#ifdef HAVE_MPLS_KERNEL
if (a[RTA_VIA])
rv->gw = rta_get_via(a[RTA_VIA]);
#endif
if (ipa_nonzero(rv->gw))
{
if (nh->rtnh_flags & RTNH_F_ONLINK)
rv->flags |= RNF_ONLINK;
neighbor *nbr;
nbr = neigh_find(&p->p, rv->gw, rv->iface,
(rv->flags & RNF_ONLINK) ? NEF_ONLINK : 0);
if (!nbr || (nbr->scope == SCOPE_HOST))
{
log(L_ERR "KRT: Received route %N with strange next-hop %I", n, rv->gw);
return NULL;
}
}
#ifdef HAVE_MPLS_KERNEL
if (a[RTA_ENCAP] && a[RTA_ENCAP_TYPE])
{
if (rta_get_u16(a[RTA_ENCAP_TYPE]) != LWTUNNEL_ENCAP_MPLS)
{
log(L_WARN "KRT: Received route %N with unknown encapsulation method %d",
n, rta_get_u16(a[RTA_ENCAP_TYPE]));
return NULL;
}
struct rtattr *enca[BIRD_RTA_MAX];
nl_attr_len = RTA_PAYLOAD(a[RTA_ENCAP]);
nl_parse_attrs(RTA_DATA(a[RTA_ENCAP]), encap_mpls_want, enca, sizeof(enca));
rv->labels = rta_get_mpls(enca[RTA_DST], rv->label);
}
#endif
next:
len -= NLMSG_ALIGN(nh->rtnh_len);
nh = RTNH_NEXT(nh);
}
/* Ensure nexthops are sorted to satisfy nest invariant */
if (!nexthop_is_sorted(first))
first = nexthop_sort(first);
return first;
err:
log(L_ERR "KRT: Received strange multipath route %N", n);
return NULL;
}
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_addr4(struct ifaddrmsg *i, int scan, int new)
{
struct rtattr *a[BIRD_IFA_MAX];
struct iface *ifi;
u32 ifa_flags;
int scope;
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;
}
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;
}
if (a[IFA_FLAGS])
ifa_flags = rta_get_u32(a[IFA_FLAGS]);
else
ifa_flags = i->ifa_flags;
struct ifa ifa;
bzero(&ifa, sizeof(ifa));
ifa.iface = ifi;
if (ifa_flags & IFA_F_SECONDARY)
ifa.flags |= IA_SECONDARY;
ifa.ip = rta_get_ipa(a[IFA_LOCAL]);
if (i->ifa_prefixlen > IP4_MAX_PREFIX_LENGTH)
{
log(L_ERR "KIF: Invalid prefix length for interface %s: %d", ifi->name, i->ifa_prefixlen);
new = 0;
}
if (i->ifa_prefixlen == IP4_MAX_PREFIX_LENGTH)
{
ifa.brd = rta_get_ipa(a[IFA_ADDRESS]);
net_fill_ip4(&ifa.prefix, rta_get_ip4(a[IFA_ADDRESS]), i->ifa_prefixlen);
/* It is either a host address or a peer address */
if (ipa_equal(ifa.ip, ifa.brd))
ifa.flags |= IA_HOST;
else
{
ifa.flags |= IA_PEER;
ifa.opposite = ifa.brd;
}
}
else
{
net_fill_ip4(&ifa.prefix, ipa_to_ip4(ifa.ip), i->ifa_prefixlen);
net_normalize(&ifa.prefix);
if (i->ifa_prefixlen == IP4_MAX_PREFIX_LENGTH - 1)
ifa.opposite = ipa_opposite_m1(ifa.ip);
if (i->ifa_prefixlen == IP4_MAX_PREFIX_LENGTH - 2)
ifa.opposite = ipa_opposite_m2(ifa.ip);
if (ifi->flags & IF_BROADCAST)
{
/* If kernel offers us a broadcast address, we trust it */
if (a[IFA_BROADCAST])
ifa.brd = ipa_from_ip4(rta_get_ip4(a[IFA_BROADCAST]));
/* Otherwise we create one (except for /31) */
else if (i->ifa_prefixlen < (IP4_MAX_PREFIX_LENGTH - 1))
ifa.brd = ipa_from_ip4(ip4_or(ipa_to_ip4(ifa.ip),
ip4_not(ip4_mkmask(i->ifa_prefixlen))));
}
}
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 %N, brd %I, opp %I\n",
ifi->index, ifi->name,
new ? "added" : "removed",
ifa.ip, ifa.flags, &ifa.prefix, ifa.brd, ifa.opposite);
if (new)
ifa_update(&ifa);
else
ifa_delete(&ifa);
if (!scan)
if_end_partial_update(ifi);
}
static void
nl_parse_addr6(struct ifaddrmsg *i, int scan, int new)
{
struct rtattr *a[BIRD_IFA_MAX];
struct iface *ifi;
u32 ifa_flags;
int scope;
if (!nl_parse_attrs(IFA_RTA(i), ifa_attr_want6, a, sizeof(a)))
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;
}
if (a[IFA_FLAGS])
ifa_flags = rta_get_u32(a[IFA_FLAGS]);
else
ifa_flags = i->ifa_flags;
struct ifa ifa;
bzero(&ifa, sizeof(ifa));
ifa.iface = ifi;
if (ifa_flags & IFA_F_SECONDARY)
ifa.flags |= IA_SECONDARY;
/* Ignore tentative addresses silently */
if (ifa_flags & IFA_F_TENTATIVE)
return;
/* IFA_LOCAL can be unset for IPv6 interfaces */
ifa.ip = rta_get_ipa(a[IFA_LOCAL] ? : a[IFA_ADDRESS]);
if (i->ifa_prefixlen > IP6_MAX_PREFIX_LENGTH)
{
log(L_ERR "KIF: Invalid prefix length for interface %s: %d", ifi->name, i->ifa_prefixlen);
new = 0;
}
if (i->ifa_prefixlen == IP6_MAX_PREFIX_LENGTH)
{
ifa.brd = rta_get_ipa(a[IFA_ADDRESS]);
net_fill_ip6(&ifa.prefix, rta_get_ip6(a[IFA_ADDRESS]), i->ifa_prefixlen);
/* It is either a host address or a peer address */
if (ipa_equal(ifa.ip, ifa.brd))
ifa.flags |= IA_HOST;
else
{
ifa.flags |= IA_PEER;
ifa.opposite = ifa.brd;
}
}
else
{
net_fill_ip6(&ifa.prefix, ipa_to_ip6(ifa.ip), i->ifa_prefixlen);
net_normalize(&ifa.prefix);
if (i->ifa_prefixlen == IP6_MAX_PREFIX_LENGTH - 1)
ifa.opposite = ipa_opposite_m1(ifa.ip);
}
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 %N, brd %I, opp %I\n",
ifi->index, ifi->name,
new ? "added" : "removed",
ifa.ip, ifa.flags, &ifa.prefix, ifa.brd, ifa.opposite);
if (new)
ifa_update(&ifa);
else
ifa_delete(&ifa);
if (!scan)
if_end_partial_update(ifi);
}
static void
nl_parse_addr(struct nlmsghdr *h, int scan)
{
struct ifaddrmsg *i;
if (!(i = nl_checkin(h, sizeof(*i))))
return;
int new = (h->nlmsg_type == RTM_NEWADDR);
switch (i->ifa_family)
{
case AF_INET:
return nl_parse_addr4(i, scan, new);
case AF_INET6:
return nl_parse_addr6(i, scan, new);
}
}
void
kif_do_scan(struct kif_proto *p UNUSED)
{
struct nlmsghdr *h;
if_start_update();
nl_request_dump_link();
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_addr(AF_INET);
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);
nl_request_dump_addr(AF_INET6);
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_KEY(p) p->af, krt_table_id(p)
#define RTH_NEXT(p) p->sys.hash_next
#define RTH_EQ(a1,i1,a2,i2) a1 == a2 && i1 == i2
#define RTH_FN(a,i) a ^ u32_hash(i)
#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;
switch (a->dest)
{
case RTD_UNICAST:
case RTD_BLACKHOLE:
case RTD_UNREACHABLE:
case RTD_PROHIBIT:
return 1;
default:
return 0;
}
}
static inline int
nh_bufsize(struct nexthop *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, int op, int dest, struct nexthop *nh)
{
eattr *ea;
net *net = e->net;
rta *a = e->attrs;
ea_list *eattrs = a->eattrs;
int bufsize = 128 + KRT_METRICS_MAX*8 + nh_bufsize(&(a->nh));
u32 priority = 0;
struct {
struct nlmsghdr h;
struct rtmsg r;
char buf[0];
} *r;
int rsize = sizeof(*r) + bufsize;
r = alloca(rsize);
DBG("nl_send_route(%N,op=%x)\n", net->n.addr, 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 = p->af;
r->r.rtm_dst_len = net_pxlen(net->n.addr);
r->r.rtm_protocol = RTPROT_BIRD;
r->r.rtm_scope = RT_SCOPE_NOWHERE;
#ifdef HAVE_MPLS_KERNEL
if (p->af == AF_MPLS)
{
/*
* Kernel MPLS code is a bit picky. We must:
* 1) Always set RT_SCOPE_UNIVERSE and RTN_UNICAST (even for RTM_DELROUTE)
* 2) Never use RTA_PRIORITY
*/
u32 label = net_mpls(net->n.addr);
nl_add_attr_mpls(&r->h, rsize, RTA_DST, 1, &label);
r->r.rtm_scope = RT_SCOPE_UNIVERSE;
r->r.rtm_type = RTN_UNICAST;
}
else
#endif
{
nl_add_attr_ipa(&r->h, rsize, RTA_DST, net_prefix(net->n.addr));
/* Add source address for IPv6 SADR routes */
if (net->n.addr->type == NET_IP6_SADR)
{
net_addr_ip6_sadr *a = (void *) &net->n.addr;
nl_add_attr_ip6(&r->h, rsize, RTA_SRC, a->src_prefix);
r->r.rtm_src_len = a->src_pxlen;
}
}
/*
* 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, rsize, RTA_TABLE, krt_table_id(p));
if (p->af == AF_MPLS)
priority = 0;
else 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, rsize, 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 (p->af == AF_MPLS)
r->r.rtm_scope = RT_SCOPE_UNIVERSE;
else if (ea = ea_find(eattrs, EA_KRT_SCOPE))
r->r.rtm_scope = ea->u.data;
else
r->r.rtm_scope = (dest == RTD_UNICAST && ipa_zero(nh->gw)) ? RT_SCOPE_LINK : RT_SCOPE_UNIVERSE;
if (ea = ea_find(eattrs, EA_KRT_PREFSRC))
nl_add_attr_ipa(&r->h, rsize, RTA_PREFSRC, *(ip_addr *)ea->u.ptr->data);
if (ea = ea_find(eattrs, EA_KRT_REALM))
nl_add_attr_u32(&r->h, rsize, 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, rsize, metrics, KRT_METRICS_MAX);
dest:
switch (dest)
{
case RTD_UNICAST:
r->r.rtm_type = RTN_UNICAST;
if (nh->next && !krt_ecmp6(p))
nl_add_multipath(&r->h, rsize, nh, p->af, eattrs);
else
{
nl_add_attr_u32(&r->h, rsize, RTA_OIF, nh->iface->index);
nl_add_nexthop(&r->h, rsize, nh, p->af);
if (nh->flags & RNF_ONLINK)
r->r.rtm_flags |= RTNH_F_ONLINK;
}
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_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)
{
rta *a = e->attrs;
int err = 0;
if (krt_ecmp6(p) && a->nh.next)
{
struct nexthop *nh = &(a->nh);
err = nl_send_route(p, e, NL_OP_ADD, RTD_UNICAST, nh);
if (err < 0)
return err;
for (nh = nh->next; nh; nh = nh->next)
err += nl_send_route(p, e, NL_OP_APPEND, RTD_UNICAST, nh);
return err;
}
return nl_send_route(p, e, NL_OP_ADD, a->dest, &(a->nh));
}
static inline int
nl_delete_rte(struct krt_proto *p, rte *e)
{
int err = 0;
/* For IPv6, we just repeatedly request DELETE until we get error */
do
err = nl_send_route(p, e, NL_OP_DELETE, RTD_NONE, NULL);
while (krt_ecmp6(p) && !err);
return err;
}
static inline int
nl_replace_rte(struct krt_proto *p, rte *e)
{
rta *a = e->attrs;
return nl_send_route(p, e, NL_OP_REPLACE, a->dest, &(a->nh));
}
void
krt_replace_rte(struct krt_proto *p, net *n UNUSED, rte *new, rte *old)
{
int err = 0;
/*
* We use NL_OP_REPLACE for IPv4, it has an issue with not checking for
* matching rtm_protocol, but that is OK when dedicated priority is used.
*
* We do not use NL_OP_REPLACE for IPv6, as it has broken semantics for ECMP
* and with some kernel versions ECMP replace crashes kernel. Would need more
* testing and checks for kernel versions.
*
* For IPv6, 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 (krt_ipv4(p) && old && new)
{
err = nl_replace_rte(p, new);
}
else
{
if (old)
nl_delete_rte(p, old);
if (new)
err = nl_add_rte(p, new);
}
if (new)
{
if (err < 0)
bmap_clear(&p->sync_map, new->id);
else
bmap_set(&p->sync_map, new->id);
}
}
static int
nl_mergable_route(struct nl_parse_state *s, net *net, struct krt_proto *p, uint priority, uint krt_type, uint rtm_family)
{
/* Route merging is used for IPv6 scans */
if (!s->scan || (rtm_family != AF_INET6))
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)
{
memset(s, 0, sizeof (struct nl_parse_state));
s->pool = nl_linpool;
s->scan = scan;
}
static inline void
nl_parse_end(struct nl_parse_state *s)
{
if (s->net)
nl_announce_route(s);
}
#define SKIP0(ARG, ...) do { DBG("KRT: Ignoring route - " ARG, ##__VA_ARGS__); return; } while(0)
#define SKIP(ARG, ...) do { DBG("KRT: Ignoring route %N - " ARG, &dst, ##__VA_ARGS__); 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;
net_addr dst, src = {};
u32 oif = ~0;
u32 table_id;
u32 priority = 0;
u32 def_scope = RT_SCOPE_UNIVERSE;
int krt_src;
if (!(i = nl_checkin(h, sizeof(*i))))
return;
switch (i->rtm_family)
{
case AF_INET:
if (!nl_parse_attrs(RTM_RTA(i), rtm_attr_want4, a, sizeof(a)))
return;
if (a[RTA_DST])
net_fill_ip4(&dst, rta_get_ip4(a[RTA_DST]), i->rtm_dst_len);
else
net_fill_ip4(&dst, IP4_NONE, 0);
break;
case AF_INET6:
if (!nl_parse_attrs(RTM_RTA(i), rtm_attr_want6, a, sizeof(a)))
return;
if (a[RTA_DST])
net_fill_ip6(&dst, rta_get_ip6(a[RTA_DST]), i->rtm_dst_len);
else
net_fill_ip6(&dst, IP6_NONE, 0);
if (a[RTA_SRC])
net_fill_ip6(&src, rta_get_ip6(a[RTA_SRC]), i->rtm_src_len);
else
net_fill_ip6(&src, IP6_NONE, 0);
break;
#ifdef HAVE_MPLS_KERNEL
case AF_MPLS:
if (!nl_parse_attrs(RTM_RTA(i), rtm_attr_want_mpls, a, sizeof(a)))
return;
if (!a[RTA_DST])
SKIP0("MPLS route without RTA_DST\n");
if (rta_get_mpls(a[RTA_DST], rta_mpls_stack) != 1)
SKIP0("MPLS route with multi-label RTA_DST\n");
net_fill_mpls(&dst, rta_mpls_stack[0]);
break;
#endif
default:
return;
}
if (a[RTA_OIF])
oif = rta_get_u32(a[RTA_OIF]);
if (a[RTA_TABLE])
table_id = rta_get_u32(a[RTA_TABLE]);
else
table_id = i->rtm_table;
if (i->rtm_flags & RTM_F_CLONED)
SKIP("cloned\n");
/* Do we know this table? */
p = HASH_FIND(nl_table_map, RTH, i->rtm_family, table_id);
if (!p)
SKIP("unknown table %u\n", table_id);
if (a[RTA_SRC] && (p->p.net_type != NET_IP6_SADR))
SKIP("src prefix for non-SADR channel\n");
if (a[RTA_IIF])
SKIP("IIF set\n");
if (i->rtm_tos != 0) /* We don't support TOS */
SKIP("TOS %02x\n", i->rtm_tos);
if (s->scan && !new)
SKIP("RTM_DELROUTE in scan\n");
if (a[RTA_PRIORITY])
priority = rta_get_u32(a[RTA_PRIORITY]);
int c = net_classify(&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:
krt_src = KRT_SRC_REDIRECT;
break;
case RTPROT_KERNEL:
krt_src = KRT_SRC_KERNEL;
return;
case RTPROT_BIRD:
if (!s->scan)
SKIP("echo\n");
krt_src = KRT_SRC_BIRD;
break;
case RTPROT_BOOT:
default:
krt_src = KRT_SRC_ALIEN;
}
net_addr *n = &dst;
if (p->p.net_type == NET_IP6_SADR)
{
n = alloca(sizeof(net_addr_ip6_sadr));
net_fill_ip6_sadr(n, net6_prefix(&dst), net6_pxlen(&dst),
net6_prefix(&src), net6_pxlen(&src));
}
net *net = net_get(p->p.main_channel->table, n);
if (s->net && !nl_mergable_route(s, net, p, priority, i->rtm_type, i->rtm_family))
nl_announce_route(s);
rta *ra = lp_allocz(s->pool, RTA_MAX_SIZE);
ra->src = p->p.main_source;
ra->source = RTS_INHERIT;
ra->scope = SCOPE_UNIVERSE;
if (a[RTA_FLOW])
s->rta_flow = rta_get_u32(a[RTA_FLOW]);
else
s->rta_flow = 0;
switch (i->rtm_type)
{
case RTN_UNICAST:
ra->dest = RTD_UNICAST;
if (a[RTA_MULTIPATH])
{
struct nexthop *nh = nl_parse_multipath(s, p, n, a[RTA_MULTIPATH], i->rtm_family, krt_src);
if (!nh)
SKIP("strange RTA_MULTIPATH\n");
nexthop_link(ra, nh);
break;
}
if ((i->rtm_flags & RTNH_F_DEAD) && (krt_src != KRT_SRC_BIRD))
SKIP("ignore RTNH_F_DEAD\n");
ra->nh.iface = if_find_by_index(oif);
if (!ra->nh.iface)
{
log(L_ERR "KRT: Received route %N with unknown ifindex %u", net->n.addr, oif);
return;
}
if (a[RTA_GATEWAY])
ra->nh.gw = rta_get_ipa(a[RTA_GATEWAY]);
#ifdef HAVE_MPLS_KERNEL
if (a[RTA_VIA])
ra->nh.gw = rta_get_via(a[RTA_VIA]);
#endif
if (ipa_nonzero(ra->nh.gw))
{
/* Silently skip strange 6to4 routes */
const net_addr_ip6 sit = NET_ADDR_IP6(IP6_NONE, 96);
if ((i->rtm_family == AF_INET6) && ipa_in_netX(ra->nh.gw, (net_addr *) &sit))
return;
if (i->rtm_flags & RTNH_F_ONLINK)
ra->nh.flags |= RNF_ONLINK;
neighbor *nbr;
nbr = neigh_find(&p->p, ra->nh.gw, ra->nh.iface,
(ra->nh.flags & RNF_ONLINK) ? NEF_ONLINK : 0);
if (!nbr || (nbr->scope == SCOPE_HOST))
{
log(L_ERR "KRT: Received route %N with strange next-hop %I", net->n.addr,
ra->nh.gw);
return;
}
}
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;
}
#ifdef HAVE_MPLS_KERNEL
if ((i->rtm_family == AF_MPLS) && a[RTA_NEWDST] && !ra->nh.next)
ra->nh.labels = rta_get_mpls(a[RTA_NEWDST], ra->nh.label);
if (a[RTA_ENCAP] && a[RTA_ENCAP_TYPE] && !ra->nh.next)
{
switch (rta_get_u16(a[RTA_ENCAP_TYPE]))
{
case LWTUNNEL_ENCAP_MPLS:
{
struct rtattr *enca[BIRD_RTA_MAX];
nl_attr_len = RTA_PAYLOAD(a[RTA_ENCAP]);
nl_parse_attrs(RTA_DATA(a[RTA_ENCAP]), encap_mpls_want, enca, sizeof(enca));
ra->nh.labels = rta_get_mpls(enca[RTA_DST], ra->nh.label);
break;
}
default:
SKIP("unknown encapsulation method %d\n", rta_get_u16(a[RTA_ENCAP_TYPE]));
break;
}
}
#endif
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 = rta_get_ipa(a[RTA_PREFSRC]);
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;
struct adata *ad = lp_alloc(s->pool, sizeof(struct adata) + sizeof(ps));
ad->length = sizeof(ps);
memcpy(ad->data, &ps, sizeof(ps));
ea->attrs[0].u.ptr = ad;
}
/* Can be set per-route or per-nexthop */
if (s->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 = s->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 %N with strange RTA_METRICS attribute", net->n.addr);
return;
}
for (t = 1; t < KRT_METRICS_MAX; t++)
if (metrics[0] & (1 << t))
{
ea->attrs[n].id = EA_CODE(PROTOCOL_KERNEL, 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
* when doing merging of next hops, we expect the new route to be unipath.
* Otherwise, we ignore additional next hops in nexthop_insert().
*/
if (!s->net)
{
/* Store the new route */
s->net = net;
s->attrs = ra;
s->proto = p;
s->new = new;
s->krt_src = krt_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 *oa = s->attrs;
struct nexthop *nhs = &oa->nh;
nexthop_insert(&nhs, &ra->nh);
/* Perhaps new nexthop is inserted at the first position */
if (nhs == &ra->nh)
{
/* Swap rtas */
s->attrs = ra;
/* Keep old eattrs */
ra->eattrs = oa->eattrs;
}
}
}
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);
nl_request_dump_route(AF_UNSPEC);
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 uint nl_async_bufsize; /* Kernel rx buffer size for the netlink socket */
static struct config *nl_last_config; /* For tracking changes to nl_async_bufsize */
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);
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;
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->err_hook = nl_async_err_hook;
sk->fd = fd;
if (sk_open(sk) < 0)
bug("Netlink: sk_open failed");
}
static void
nl_update_async_bufsize(void)
{
/* No async socket */
if (!nl_async_sk)
return;
/* Already reconfigured */
if (nl_last_config == config)
return;
/* Update netlink buffer size */
uint bufsize = nl_cfg_rx_buffer_size(config);
if (bufsize && (bufsize != nl_async_bufsize))
{
/* Log message for reconfigurations only */
if (nl_last_config)
log(L_INFO "KRT: Changing netlink rx buffer size to %u", bufsize);
nl_set_rcvbuf(nl_async_sk->fd, bufsize);
nl_async_bufsize = bufsize;
}
nl_last_config = config;
}
/*
* Interface to the UNIX krt module
*/
void
krt_sys_io_init(void)
{
nl_linpool = lp_new_default(krt_pool);
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, p->af, 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();
nl_update_async_bufsize();
return 1;
}
void
krt_sys_shutdown(struct krt_proto *p)
{
nl_update_async_bufsize();
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)
{
nl_update_async_bufsize();
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 = 32;
}
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(const 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)
{
}
int
kif_update_sysdep_addr(struct iface *i UNUSED)
{
return 0;
}
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