/* * BIRD -- Linux Netlink Interface * * (c) 1999--2000 Martin Mares * * Can be freely distributed and used under the terms of the GNU GPL. */ #include #include #include #include #include #include #include #undef LOCAL_DEBUG #include "nest/bird.h" #include "nest/rt.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 "lib/macro.h" #include "conf/conf.h" #include #include #include #include #ifdef HAVE_MPLS_KERNEL #include #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) const int rt_default_ecmp = 16; struct nl_parse_state { struct krt_proto *proto; struct linpool *pool; int scan; u32 rta_flow; }; /* * Netlink eattr definitions */ #define KRT_METRICS_MAX ARRAY_SIZE(ea_krt_metrics) #define KRT_FEATURES_MAX 4 static void krt_bitfield_format(const eattr *e, byte *buf, uint buflen); static struct ea_class ea_krt_prefsrc = { .name = "krt_prefsrc", .type = T_IP, }, ea_krt_realm = { .name = "krt_realm", .type = T_INT, }, ea_krt_scope = { .name = "krt_scope", .type = T_INT, }; static struct ea_class ea_krt_metrics[] = { [RTAX_LOCK] = { .name = "krt_lock", .type = T_INT, .format = krt_bitfield_format, }, [RTAX_FEATURES] = { .name = "krt_features", .type = T_INT, .format = krt_bitfield_format, }, #define KRT_METRIC_INT(_rtax, _name) [_rtax] = { .name = _name, .type = T_INT } KRT_METRIC_INT(RTAX_MTU, "krt_mtu"), KRT_METRIC_INT(RTAX_WINDOW, "krt_window"), KRT_METRIC_INT(RTAX_RTT, "krt_rtt"), KRT_METRIC_INT(RTAX_RTTVAR, "krt_rttvar"), KRT_METRIC_INT(RTAX_SSTHRESH, "krt_sstresh"), KRT_METRIC_INT(RTAX_CWND, "krt_cwnd"), KRT_METRIC_INT(RTAX_ADVMSS, "krt_advmss"), KRT_METRIC_INT(RTAX_REORDERING, "krt_reordering"), KRT_METRIC_INT(RTAX_HOPLIMIT, "krt_hoplimit"), KRT_METRIC_INT(RTAX_INITCWND, "krt_initcwnd"), KRT_METRIC_INT(RTAX_RTO_MIN, "krt_rto_min"), KRT_METRIC_INT(RTAX_INITRWND, "krt_initrwnd"), KRT_METRIC_INT(RTAX_QUICKACK, "krt_quickack"), #undef KRT_METRIC_INT }; 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" }; static void krt_bitfield_format(const eattr *a, byte *buf, uint buflen) { if (a->id == ea_krt_metrics[RTAX_LOCK].id) ea_format_bitfield(a, buf, buflen, krt_metrics_names, 2, KRT_METRICS_MAX); else if (a->id == ea_krt_metrics[RTAX_FEATURES].id) ea_format_bitfield(a, buf, buflen, krt_features_names, 0, KRT_FEATURES_MAX); } static void nl_ea_register(void) { EA_REGISTER_ALL( &ea_krt_prefsrc, &ea_krt_realm, &ea_krt_scope ); for (uint i = 0; i < KRT_METRICS_MAX; i++) { if (!ea_krt_metrics[i].name) ea_krt_metrics[i] = (struct ea_class) { .name = mb_sprintf(&root_pool, "krt_metric_%d", i), .type = T_INT, }; ea_register_init(&ea_krt_metrics[i]); } for (uint i = 1; i < KRT_METRICS_MAX; i++) ASSERT_DIE(ea_krt_metrics[i].id == ea_krt_metrics[0].id + i); } /* * 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 int nl_set_strict_dump(struct nl_sock *nl UNUSED, int strict UNUSED) { #ifdef SOL_NETLINK return setsockopt(nl->fd, SOL_NETLINK, NETLINK_GET_STRICT_CHK, &strict, sizeof(strict)); #else return -1; #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) { if ((nl_scan.fd >= 0) && (nl_req.fd >= 0)) return; nl_open_sock(&nl_scan); nl_open_sock(&nl_req); if (nl_set_strict_dump(&nl_scan, 1) < 0) { log(L_WARN "KRT: Netlink strict checking failed, will scan all tables at once"); krt_use_shared_scan(); } } 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, int table_id) { struct { struct nlmsghdr nh; struct rtmsg rtm; struct rtattr rta; u32 table_id; } 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, }; if (table_id < 256) req.rtm.rtm_table = table_id; else { req.rta.rta_type = RTA_TABLE; req.rta.rta_len = RTA_LENGTH(4); req.table_id = table_id; req.nh.nlmsg_len = NLMSG_ALIGN(req.nh.nlmsg_len) + req.rta.rta_len; } send(nl_scan.fd, &req, req.nh.nlmsg_len, 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_adata *nhad, int af, ea_list *eattrs) { struct rtattr *a = nl_open_attr(h, bufsize, RTA_MULTIPATH); eattr *flow = ea_find(eattrs, &ea_krt_realm); NEXTHOP_WALK(nh, nhad) { 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_adata * 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, *orig_nh = RTA_DATA(ra); unsigned len, orig_len = RTA_PAYLOAD(ra); uint cnt = 0; /* First count the nexthops */ for (len = orig_len, nh = orig_nh; len; len -= NLMSG_ALIGN(nh->rtnh_len), nh = RTNH_NEXT(nh)) { /* 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)) ; else cnt++; } struct nexthop_adata *nhad = lp_allocz(s->pool, cnt * NEXTHOP_MAX_SIZE + sizeof *nhad); struct nexthop *rv = &nhad->nh; for (len = orig_len, nh = orig_nh; len; len -= NLMSG_ALIGN(nh->rtnh_len), nh = RTNH_NEXT(nh)) { /* 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)) continue; *rv = (struct nexthop) { .weight = nh->rtnh_hops, .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 (nh->rtnh_flags & RTNH_F_ONLINK) rv->flags |= RNF_ONLINK; if (ipa_nonzero(rv->gw)) { 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 rv = NEXTHOP_NEXT(rv); } /* Store final length */ nhad->ad.length = (void *) rv - (void *) nhad->ad.data; /* Ensure nexthops are sorted to satisfy nest invariant */ return nexthop_is_sorted(nhad) ? nhad : nexthop_sort(nhad, s->pool); 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) { eattr *ea = ea_find(e->attrs, &ea_gen_nexthop); if (!ea) return 0; struct nexthop_adata *nhad = (void *) ea->u.ptr; if (NEXTHOP_IS_REACHABLE(nhad)) return 1; switch (nhad->dest) { case RTD_BLACKHOLE: case RTD_UNREACHABLE: case RTD_PROHIBIT: return 1; default: return 0; } } static inline int nh_bufsize(struct nexthop_adata *nhad) { int rv = 0; NEXTHOP_WALK(nh, nhad) rv += RTNH_LENGTH(RTA_LENGTH(sizeof(ip_addr))); return rv; } static int nl_send_route(struct krt_proto *p, const rte *e, int op) { eattr *ea; ea_list *eattrs = e->attrs; eattr *nhea = ea_find(eattrs, &ea_gen_nexthop); struct nexthop_adata *nh = nhea ? (struct nexthop_adata *) nhea->u.ptr : NULL; int dest = nhea_dest(nhea); int bufsize = 128 + KRT_METRICS_MAX*8 + (nh ? nh_bufsize(nh) : 0); 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", e->net, 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(e->net); 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(e->net); 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(e->net)); /* Add source address for IPv6 SADR routes */ if (e->net->type == NET_IP6_SADR) { net_addr_ip6_sadr *a = (void *) &e->net; 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 (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 done; /* 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 if (dest == RTD_UNICAST && ipa_zero(nh->nh.gw)) r->r.rtm_scope = RT_SCOPE_LINK; else r->r.rtm_scope = 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[0].id, KRT_METRICS_MAX)) { int id = ea->id - ea_krt_metrics[0].id; metrics[0] |= 1 << id; metrics[id] = ea->u.data; } if (metrics[0]) nl_add_metrics(&r->h, rsize, metrics, KRT_METRICS_MAX); switch (dest) { case RTD_UNICAST: r->r.rtm_type = RTN_UNICAST; if (!NEXTHOP_ONE(nh)) nl_add_multipath(&r->h, rsize, nh, p->af, eattrs); else { nl_add_attr_u32(&r->h, rsize, RTA_OIF, nh->nh.iface->index); nl_add_nexthop(&r->h, rsize, &nh->nh, p->af); if (nh->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"); } done: /* Ignore missing for DELETE */ return nl_exchange(&r->h, (op == NL_OP_DELETE)); } static inline int nl_allow_replace(struct krt_proto *p, rte *new) { /* * 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. * * For IPv6, the NL_OP_REPLACE is still broken even in Linux 4.19 LTS * (although it seems to be fixed in Linux 5.10 LTS) for sequence: * * ip route add 2001:db8::/32 via fe80::1 dev eth0 * ip route replace 2001:db8::/32 dev eth0 * * (it ends with two routes instead of replacing the first by the second one) * * Replacing with direct and special type (e.g. unreachable) routes does not * work, but replacing with regular routes work reliably */ if (krt_ipv4(p)) return 1; eattr *nhea = ea_find(new->attrs, &ea_gen_nexthop); struct nexthop_adata *nh = nhea ? (struct nexthop_adata *) nhea->u.ptr : NULL; int dest = nhea_dest(nhea); return (dest == RTD_UNICAST) && ipa_nonzero(nh->nh.gw); } void krt_replace_rte(struct krt_proto *p, const net_addr *n UNUSED, rte *new, const rte *old) { int err = 0; if (old && new && nl_allow_replace(p, new)) { err = nl_send_route(p, new, NL_OP_REPLACE); } else { if (old) nl_send_route(p, old, NL_OP_DELETE); if (new) err = nl_send_route(p, new, NL_OP_ADD); } if (new) { if (err < 0) bmap_clear(&p->sync_map, new->id); else bmap_set(&p->sync_map, new->id); } } #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 *net = &dst; if (p->p.net_type == NET_IP6_SADR) { net = alloca(sizeof(net_addr_ip6_sadr)); net_fill_ip6_sadr(net, net6_prefix(&dst), net6_pxlen(&dst), net6_prefix(&src), net6_pxlen(&src)); } ea_list *ra = NULL; ea_set_attr_u32(&ra, &ea_gen_source, 0, RTS_INHERIT); ea_set_attr_u32(&ra, &ea_krt_source, 0, i->rtm_protocol); ea_set_attr_u32(&ra, &ea_krt_metric, 0, priority); if (a[RTA_FLOW]) s->rta_flow = rta_get_u32(a[RTA_FLOW]); else s->rta_flow = 0; union { struct { struct adata ad; struct nexthop nh; u32 labels[MPLS_MAX_LABEL_STACK]; }; struct nexthop_adata nhad; } nhad = {}; switch (i->rtm_type) { case RTN_UNICAST: if (a[RTA_MULTIPATH]) { struct nexthop_adata *nh = nl_parse_multipath(s, p, net, a[RTA_MULTIPATH], i->rtm_family, krt_src); if (!nh) SKIP("strange RTA_MULTIPATH\n"); ea_set_attr(&ra, EA_LITERAL_DIRECT_ADATA( &ea_gen_nexthop, 0, &nh->ad)); break; } if ((i->rtm_flags & RTNH_F_DEAD) && (krt_src != KRT_SRC_BIRD)) SKIP("ignore RTNH_F_DEAD\n"); nhad.nh.iface = if_find_by_index(oif); if (!nhad.nh.iface) { log(L_ERR "KRT: Received route %N with unknown ifindex %u", net, oif); return; } if (a[RTA_GATEWAY]) nhad.nh.gw = rta_get_ipa(a[RTA_GATEWAY]); #ifdef HAVE_MPLS_KERNEL if (a[RTA_VIA]) nhad.nh.gw = rta_get_via(a[RTA_VIA]); #endif if (i->rtm_flags & RTNH_F_ONLINK) nhad.nh.flags |= RNF_ONLINK; if (ipa_nonzero(nhad.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(nhad.nh.gw, (net_addr *) &sit)) return; neighbor *nbr; nbr = neigh_find(&p->p, nhad.nh.gw, nhad.nh.iface, (nhad.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, nhad.nh.gw); return; } } #ifdef HAVE_MPLS_KERNEL if ((i->rtm_family == AF_MPLS) && a[RTA_NEWDST] && !a[RTA_MULTIPATH]) nhad.nh.labels = rta_get_mpls(a[RTA_NEWDST], nhad.nh.label); if (a[RTA_ENCAP] && a[RTA_ENCAP_TYPE] && !a[RTA_MULTIPATH]) { 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)); nhad.nh.labels = rta_get_mpls(enca[RTA_DST], nhad.nh.label); break; } default: SKIP("unknown encapsulation method %d\n", rta_get_u16(a[RTA_ENCAP_TYPE])); break; } } #endif /* Finalize the nexthop */ nhad.ad.length = (void *) NEXTHOP_NEXT(&nhad.nh) - (void *) nhad.ad.data; break; case RTN_BLACKHOLE: nhad.nhad = NEXTHOP_DEST_LITERAL(RTD_BLACKHOLE); break; case RTN_UNREACHABLE: nhad.nhad = NEXTHOP_DEST_LITERAL(RTD_UNREACHABLE); break; case RTN_PROHIBIT: nhad.nhad = NEXTHOP_DEST_LITERAL(RTD_PROHIBIT); break; /* FIXME: What about RTN_THROW? */ default: SKIP("type %d\n", i->rtm_type); return; } if (nhad.ad.length) ea_set_attr(&ra, EA_LITERAL_DIRECT_ADATA(&ea_gen_nexthop, 0, &nhad.ad)); if (i->rtm_scope != def_scope) ea_set_attr(&ra, EA_LITERAL_EMBEDDED(&ea_krt_scope, 0, i->rtm_scope)); if (a[RTA_PREFSRC]) { ip_addr ps = rta_get_ipa(a[RTA_PREFSRC]); ea_set_attr(&ra, EA_LITERAL_STORE_ADATA(&ea_krt_prefsrc, 0, &ps, sizeof(ps))); } /* Can be set per-route or per-nexthop */ if (s->rta_flow) ea_set_attr(&ra, EA_LITERAL_EMBEDDED(&ea_krt_realm, 0, s->rta_flow)); if (a[RTA_METRICS]) { u32 metrics[KRT_METRICS_MAX]; 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); return; } for (uint t = 1; t < KRT_METRICS_MAX; t++) if (metrics[0] & (1 << t)) ea_set_attr(&ra, EA_LITERAL_EMBEDDED(&ea_krt_metrics[t], 0, metrics[t])); } rte e0 = { .net = net, .attrs = ra, }; if (s->scan) krt_got_route(p, &e0, krt_src); else krt_got_route_async(p, &e0, new, krt_src); lp_flush(s->pool); } void krt_do_scan(struct krt_proto *p) { struct nl_parse_state s = { .proto = p, .pool = nl_linpool, .scan = 1, }; /* Table-specific scan or shared scan */ if (p) nl_request_dump_route(p->af, krt_table_id(p)); else nl_request_dump_route(AF_UNSPEC, 0); struct nlmsghdr *h; 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); } } /* * 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 = { .proto = NULL, .pool = nl_linpool, .scan = 0, }; switch (h->nlmsg_type) { case RTM_NEWROUTE: case RTM_DELROUTE: DBG("KRT: Received async route notification (%d)\n", h->nlmsg_type); nl_parse_route(&s, h); 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); nl_ea_register(); } 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; } 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; }