/* * 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 Linux kernel represents * and announces IPv6 ECMP routes not as one route with multiple next hops (like * RTA_MULTIPATH in IPv4 ECMP), but as a set of routes with the same prefix. * * 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 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. */ 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_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) static struct nl_want_attrs mpnh_attr_want4[BIRD_RTA_MAX] = { [RTA_GATEWAY] = { 1, 1, sizeof(ip4_addr) }, }; #ifndef IPV6 static struct nl_want_attrs rtm_attr_want4[BIRD_RTA_MAX] = { [RTA_DST] = { 1, 1, sizeof(ip4_addr) }, [RTA_OIF] = { 1, 1, sizeof(u32) }, [RTA_GATEWAY] = { 1, 1, sizeof(ip4_addr) }, [RTA_PRIORITY] = { 1, 1, sizeof(u32) }, [RTA_PREFSRC] = { 1, 1, sizeof(ip4_addr) }, [RTA_METRICS] = { 1, 0, 0 }, [RTA_MULTIPATH] = { 1, 0, 0 }, [RTA_FLOW] = { 1, 1, sizeof(u32) }, [RTA_TABLE] = { 1, 1, sizeof(u32) }, }; #else static struct nl_want_attrs rtm_attr_want6[BIRD_RTA_MAX] = { [RTA_DST] = { 1, 1, sizeof(ip6_addr) }, [RTA_IIF] = { 1, 1, sizeof(u32) }, [RTA_OIF] = { 1, 1, sizeof(u32) }, [RTA_GATEWAY] = { 1, 1, sizeof(ip6_addr) }, [RTA_PRIORITY] = { 1, 1, sizeof(u32) }, [RTA_PREFSRC] = { 1, 1, sizeof(ip6_addr) }, [RTA_METRICS] = { 1, 0, 0 }, [RTA_FLOW] = { 1, 1, sizeof(u32) }, [RTA_TABLE] = { 1, 1, sizeof(u32) }, }; #endif static int nl_parse_attrs(struct rtattr *a, struct nl_want_attrs *want, struct rtattr **k, int ksize) { int max = ksize / sizeof(struct rtattr *); bzero(k, ksize); for ( ; RTA_OK(a, nl_attr_len); a = RTA_NEXT(a, nl_attr_len)) { if ((a->rta_type >= max) || !want[a->rta_type].defined) continue; if (want[a->rta_type].checksize && (RTA_PAYLOAD(a) != want[a->rta_type].size)) { log(L_ERR "nl_parse_attrs: Malformed message received"); return 0; } k[a->rta_type] = a; } if (nl_attr_len) { log(L_ERR "nl_parse_attrs: remnant of size %d", nl_attr_len); return 0; } return 1; } static inline u32 rta_get_u32(struct rtattr *a) { return *(u32 *) RTA_DATA(a); } static inline ip4_addr rta_get_ip4(struct rtattr *a) { return ip4_ntoh(*(ip4_addr *) RTA_DATA(a)); } static inline ip6_addr rta_get_ip6(struct rtattr *a) { return ip6_ntoh(*(ip6_addr *) RTA_DATA(a)); } struct rtattr * nl_add_attr(struct nlmsghdr *h, uint bufsize, uint code, const void *data, uint dlen) { uint pos = NLMSG_ALIGN(h->nlmsg_len); uint len = RTA_LENGTH(dlen); if (pos + len > bufsize) bug("nl_add_attr: packet buffer overflow"); struct rtattr *a = (struct rtattr *)((char *)h + pos); a->rta_type = code; a->rta_len = len; h->nlmsg_len = pos + len; if (dlen > 0) memcpy(RTA_DATA(a), data, dlen); return a; } static inline void nl_add_attr_u32(struct nlmsghdr *h, unsigned bufsize, int code, u32 data) { nl_add_attr(h, bufsize, code, &data, 4); } static inline void nl_add_attr_ipa(struct nlmsghdr *h, unsigned bufsize, int code, ip_addr ipa) { ipa_hton(ipa); nl_add_attr(h, bufsize, code, &ipa, sizeof(ipa)); } static inline struct rtattr * nl_open_attr(struct nlmsghdr *h, uint bufsize, uint code) { return nl_add_attr(h, bufsize, code, NULL, 0); } static inline void nl_close_attr(struct nlmsghdr *h, struct rtattr *a) { a->rta_len = (void *)h + NLMSG_ALIGN(h->nlmsg_len) - (void *)a; } static inline struct rtnexthop * nl_open_nexthop(struct nlmsghdr *h, uint bufsize) { uint pos = NLMSG_ALIGN(h->nlmsg_len); uint len = RTNH_LENGTH(0); if (pos + len > bufsize) bug("nl_open_nexthop: packet buffer overflow"); h->nlmsg_len = pos + len; return (void *)h + pos; } static inline void nl_close_nexthop(struct nlmsghdr *h, struct rtnexthop *nh) { nh->rtnh_len = (void *)h + NLMSG_ALIGN(h->nlmsg_len) - (void *)nh; } static void nl_add_multipath(struct nlmsghdr *h, unsigned bufsize, struct mpnh *nh) { struct rtattr *a = nl_open_attr(h, bufsize, RTA_MULTIPATH); for (; nh; nh = nh->next) { struct rtnexthop *rtnh = nl_open_nexthop(h, bufsize); rtnh->rtnh_flags = 0; rtnh->rtnh_hops = nh->weight; rtnh->rtnh_ifindex = nh->iface->index; nl_add_attr_ipa(h, bufsize, RTA_GATEWAY, nh->gw); nl_close_nexthop(h, rtnh); } nl_close_attr(h, a); } static struct mpnh * nl_parse_multipath(struct krt_proto *p, struct rtattr *ra) { /* Temporary buffer for multicast nexthops */ static struct mpnh *nh_buffer; static int nh_buf_size; /* in number of structures */ static int nh_buf_used; struct rtattr *a[BIRD_RTA_MAX]; struct rtnexthop *nh = RTA_DATA(ra); struct mpnh *rv, *first, **last; int len = RTA_PAYLOAD(ra); first = NULL; last = &first; nh_buf_used = 0; while (len) { /* Use RTNH_OK(nh,len) ?? */ if ((len < sizeof(*nh)) || (len < nh->rtnh_len)) return NULL; if (nh_buf_used == nh_buf_size) { nh_buf_size = nh_buf_size ? (nh_buf_size * 2) : 4; nh_buffer = xrealloc(nh_buffer, nh_buf_size * sizeof(struct mpnh)); } *last = rv = nh_buffer + nh_buf_used++; rv->next = NULL; last = &(rv->next); rv->weight = nh->rtnh_hops; rv->iface = if_find_by_index(nh->rtnh_ifindex); if (!rv->iface) return NULL; /* Nonexistent RTNH_PAYLOAD ?? */ nl_attr_len = nh->rtnh_len - RTNH_LENGTH(0); nl_parse_attrs(RTNH_DATA(nh), mpnh_attr_want4, a, sizeof(a)); if (a[RTA_GATEWAY]) { memcpy(&rv->gw, RTA_DATA(a[RTA_GATEWAY]), sizeof(ip_addr)); ipa_ntoh(rv->gw); neighbor *ng = neigh_find2(&p->p, &rv->gw, rv->iface, (nh->rtnh_flags & RTNH_F_ONLINK) ? NEF_ONLINK : 0); if (!ng || (ng->scope == SCOPE_HOST)) return NULL; } else return NULL; len -= NLMSG_ALIGN(nh->rtnh_len); nh = RTNH_NEXT(nh); } return first; } static void nl_add_metrics(struct nlmsghdr *h, uint bufsize, u32 *metrics, int max) { struct rtattr *a = nl_open_attr(h, bufsize, RTA_METRICS); int t; for (t = 1; t < max; t++) if (metrics[0] & (1 << t)) nl_add_attr_u32(h, bufsize, t, metrics[t]); nl_close_attr(h, a); } static int nl_parse_metrics(struct rtattr *hdr, u32 *metrics, int max) { struct rtattr *a = RTA_DATA(hdr); int len = RTA_PAYLOAD(hdr); metrics[0] = 0; for (; RTA_OK(a, len); a = RTA_NEXT(a, len)) { if (a->rta_type == RTA_UNSPEC) continue; if (a->rta_type >= max) continue; if (RTA_PAYLOAD(a) != 4) return -1; metrics[0] |= 1 << a->rta_type; metrics[a->rta_type] = rta_get_u32(a); } if (len > 0) return -1; return 0; } /* * Scanning of interfaces */ static void nl_parse_link(struct nlmsghdr *h, int scan) { struct ifinfomsg *i; struct rtattr *a[BIRD_IFLA_MAX]; int new = h->nlmsg_type == RTM_NEWLINK; struct iface f = {}; struct iface *ifi; char *name; u32 mtu; uint fl; if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFLA_RTA(i), ifla_attr_want, a, sizeof(a))) return; if (!a[IFLA_IFNAME] || (RTA_PAYLOAD(a[IFLA_IFNAME]) < 2) || !a[IFLA_MTU]) { /* * IFLA_IFNAME and IFLA_MTU are required, in fact, but there may also come * a message with IFLA_WIRELESS set, where (e.g.) no IFLA_IFNAME exists. * We simply ignore all such messages with IFLA_WIRELESS without notice. */ if (a[IFLA_WIRELESS]) return; log(L_ERR "KIF: Malformed message received"); return; } name = RTA_DATA(a[IFLA_IFNAME]); mtu = rta_get_u32(a[IFLA_MTU]); ifi = if_find_by_index(i->ifi_index); if (!new) { DBG("KIF: IF%d(%s) goes down\n", i->ifi_index, name); if (!ifi) return; if_delete(ifi); } else { DBG("KIF: IF%d(%s) goes up (mtu=%d,flg=%x)\n", i->ifi_index, name, mtu, i->ifi_flags); if (ifi && strncmp(ifi->name, name, sizeof(ifi->name)-1)) if_delete(ifi); strncpy(f.name, name, sizeof(f.name)-1); f.index = i->ifi_index; f.mtu = mtu; fl = i->ifi_flags; if (fl & IFF_UP) f.flags |= IF_ADMIN_UP; if (fl & IFF_LOWER_UP) f.flags |= IF_LINK_UP; if (fl & IFF_LOOPBACK) /* Loopback */ f.flags |= IF_MULTIACCESS | IF_LOOPBACK | IF_IGNORE; else if (fl & IFF_POINTOPOINT) /* PtP */ f.flags |= IF_MULTICAST; else if (fl & IFF_BROADCAST) /* Broadcast */ f.flags |= IF_MULTIACCESS | IF_BROADCAST | IF_MULTICAST; else f.flags |= IF_MULTIACCESS; /* NBMA */ if (fl & IFF_MULTICAST) f.flags |= IF_MULTICAST; ifi = if_update(&f); if (!scan) if_end_partial_update(ifi); } } static void nl_parse_addr(struct nlmsghdr *h, int scan) { struct ifaddrmsg *i; struct rtattr *a[BIRD_IFA_MAX]; int new = h->nlmsg_type == RTM_NEWADDR; struct ifa ifa; struct iface *ifi; int scope; 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); 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_UNIVERSE; 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; 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; 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"); // ignore rtm_scope, it is not a real scope // if (i->rtm_scope != RT_SCOPE_UNIVERSE) // SKIP("scope %u\n", i->rtm_scope); switch (i->rtm_protocol) { case RTPROT_UNSPEC: SKIP("proto unspec\n"); case RTPROT_REDIRECT: src = KRT_SRC_REDIRECT; break; case RTPROT_KERNEL: src = KRT_SRC_KERNEL; return; case RTPROT_BIRD: if (!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] && (i->rtm_family == AF_INET)) { ra->dest = RTD_MULTIPATH; ra->nexthops = nl_parse_multipath(p, a[RTA_MULTIPATH]); if (!ra->nexthops) { log(L_ERR "KRT: Received strange multipath route %I/%d", net->n.prefix, net->n.pxlen); return; } break; } ra->iface = if_find_by_index(oif); if (!ra->iface) { log(L_ERR "KRT: Received route %I/%d with unknown ifindex %u", net->n.prefix, net->n.pxlen, oif); return; } if (a[RTA_GATEWAY]) { neighbor *ng; ra->dest = RTD_ROUTER; memcpy(&ra->gw, RTA_DATA(a[RTA_GATEWAY]), sizeof(ra->gw)); ipa_ntoh(ra->gw); #ifdef IPV6 /* Silently skip strange 6to4 routes */ if (ipa_in_net(ra->gw, IPA_NONE, 96)) return; #endif ng = neigh_find2(&p->p, &ra->gw, ra->iface, (i->rtm_flags & RTNH_F_ONLINK) ? NEF_ONLINK : 0); if (!ng || (ng->scope == SCOPE_HOST)) { log(L_ERR "KRT: Received route %I/%d with strange next-hop %I", net->n.prefix, net->n.pxlen, ra->gw); return; } } else { ra->dest = RTD_DEVICE; } break; case RTN_BLACKHOLE: ra->dest = RTD_BLACKHOLE; break; case RTN_UNREACHABLE: ra->dest = RTD_UNREACHABLE; break; case RTN_PROHIBIT: ra->dest = RTD_PROHIBIT; break; /* FIXME: What about RTN_THROW? */ default: SKIP("type %d\n", i->rtm_type); return; } 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 are sent as a sequence of routes, so we postpone it * and merge next hops until the end of the sequence. */ 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, int 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. */ return 1; /* More data are likely to be ready */ } else if (errno != EWOULDBLOCK) log(L_ERR "Netlink recvmsg: %m"); return 0; } if (sa.nl_pid) /* It isn't from the kernel */ { DBG("Non-kernel packet\n"); return 1; } h = (void *) nl_async_rx_buffer; len = x; if (m.msg_flags & MSG_TRUNC) { log(L_WARN "Netlink got truncated asynchronous message"); return 1; } while (NLMSG_OK(h, len)) { nl_async_msg(h); h = NLMSG_NEXT(h, len); } if (len) log(L_WARN "nl_async_hook: Found packet remnant of size %d", len); return 1; } static void nl_open_async(void) { sock *sk; struct sockaddr_nl sa; int fd; if (nl_async_sk) return; DBG("KRT: Opening async netlink socket\n"); fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE); if (fd < 0) { log(L_ERR "Unable to open asynchronous rtnetlink socket: %m"); return; } bzero(&sa, sizeof(sa)); sa.nl_family = AF_NETLINK; #ifdef IPV6 sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV6_IFADDR | RTMGRP_IPV6_ROUTE; #else sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV4_ROUTE; #endif if (bind(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0) { log(L_ERR "Unable to bind asynchronous rtnetlink socket: %m"); close(fd); return; } nl_async_rx_buffer = xmalloc(NL_RX_SIZE); sk = nl_async_sk = sk_new(krt_pool); sk->type = SK_MAGIC; sk->rx_hook = nl_async_hook; sk->fd = fd; if (sk_open(sk) < 0) bug("Netlink: sk_open failed"); } /* * Interface to the UNIX krt module */ void krt_sys_io_init(void) { 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_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) { }