diff options
| -rw-r--r-- | sysdep/linux/netlink.c | 354 |
1 files changed, 277 insertions, 77 deletions
diff --git a/sysdep/linux/netlink.c b/sysdep/linux/netlink.c index fa9013bd..1ab1cda1 100644 --- a/sysdep/linux/netlink.c +++ b/sysdep/linux/netlink.c @@ -19,7 +19,6 @@ #include "nest/route.h" #include "nest/protocol.h" #include "nest/iface.h" -#include "lib/alloca.h" #include "lib/timer.h" #include "lib/unix.h" #include "lib/krt.h" @@ -51,6 +50,49 @@ #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 */ @@ -66,6 +108,13 @@ struct nl_sock #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 */ @@ -169,7 +218,7 @@ nl_get_reply(struct nl_sock *nl) static struct tbf rl_netlink_err = TBF_DEFAULT_LOG_LIMITS; static int -nl_error(struct nlmsghdr *h) +nl_error(struct nlmsghdr *h, int ignore_esrch) { struct nlmsgerr *e; int ec; @@ -181,7 +230,7 @@ nl_error(struct nlmsghdr *h) } e = (struct nlmsgerr *) NLMSG_DATA(h); ec = -e->error; - if (ec) + if (ec && !(ignore_esrch && (ec == ESRCH))) log_rl(&rl_netlink_err, L_WARN "Netlink: %s", strerror(ec)); return ec; } @@ -195,14 +244,14 @@ nl_get_scan(void) return NULL; if (h->nlmsg_type == NLMSG_ERROR) { - nl_error(h); + nl_error(h, 0); return NULL; } return h; } static int -nl_exchange(struct nlmsghdr *pkt) +nl_exchange(struct nlmsghdr *pkt, int ignore_esrch) { struct nlmsghdr *h; @@ -214,7 +263,7 @@ nl_exchange(struct nlmsghdr *pkt) break; log(L_WARN "nl_exchange: Unexpected reply received"); } - return nl_error(h) ? -1 : 0; + return nl_error(h, ignore_esrch) ? -1 : 0; } /* @@ -826,7 +875,7 @@ nh_bufsize(struct mpnh *nh) } static int -nl_send_route(struct krt_proto *p, rte *e, struct ea_list *eattrs, int new) +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; @@ -837,13 +886,13 @@ nl_send_route(struct krt_proto *p, rte *e, struct ea_list *eattrs, int new) char buf[128 + KRT_METRICS_MAX*8 + nh_bufsize(a->nexthops)]; } r; - DBG("nl_send_route(%I/%d,new=%d)\n", net->n.prefix, net->n.pxlen, new); + 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 = new ? RTM_NEWROUTE : RTM_DELROUTE; + r.h.nlmsg_type = op ? RTM_NEWROUTE : RTM_DELROUTE; r.h.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg)); - r.h.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | (new ? NLM_F_CREATE|NLM_F_EXCL : 0); + 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; @@ -851,15 +900,21 @@ nl_send_route(struct krt_proto *p, rte *e, struct ea_list *eattrs, int new) 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)); - /* For route delete, we do not specify route attributes */ - if (!new) - return nl_exchange(&r.h); - + /* For route delete, we do not specify remaining route attributes */ + if (op == NL_OP_DELETE) + goto dest; if (ea = ea_find(eattrs, EA_KRT_METRIC)) nl_add_attr_u32(&r.h, sizeof(r), RTA_PRIORITY, ea->u.data); @@ -886,18 +941,18 @@ nl_send_route(struct krt_proto *p, rte *e, struct ea_list *eattrs, int new) 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 (a->dest) + switch (dest) { case RTD_ROUTER: r.r.rtm_type = RTN_UNICAST; - nl_add_attr_u32(&r.h, sizeof(r), RTA_OIF, a->iface->index); - nl_add_attr_ipa(&r.h, sizeof(r), RTA_GATEWAY, a->gw); + 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, a->iface->index); + nl_add_attr_u32(&r.h, sizeof(r), RTA_OIF, iface->index); break; case RTD_BLACKHOLE: r.r.rtm_type = RTN_BLACKHOLE; @@ -912,11 +967,50 @@ nl_send_route(struct krt_proto *p, rte *e, struct ea_list *eattrs, int new) 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"); } - return nl_exchange(&r.h); + /* 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 @@ -925,17 +1019,21 @@ krt_replace_rte(struct krt_proto *p, net *n, rte *new, rte *old, struct ea_list int err = 0; /* - * NULL for eattr of the old route is a little hack, but we don't - * get proper eattrs for old in rt_notify() anyway. NULL means no - * extended route attributes and therefore matches if the kernel - * route has any of them. + * 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_send_route(p, old, NULL, 0); + nl_delete_rte(p, old, eattrs); if (new) - err = nl_send_route(p, new, eattrs, 1); + err = nl_add_rte(p, new, eattrs); if (err < 0) n->n.flags |= KRF_SYNC_ERROR; @@ -944,10 +1042,80 @@ krt_replace_rte(struct krt_proto *p, net *n, rte *new, rte *old, struct ea_list } +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 nlmsghdr *h, int scan) +nl_parse_route(struct nl_parse_state *s, struct nlmsghdr *h) { struct krt_proto *p; struct rtmsg *i; @@ -957,6 +1125,7 @@ nl_parse_route(struct nlmsghdr *h, int scan) ip_addr dst = IPA_NONE; u32 oif = ~0; u32 table; + u32 priority = 0; int src; if (!(i = nl_checkin(h, sizeof(*i)))) @@ -999,7 +1168,6 @@ nl_parse_route(struct nlmsghdr *h, int scan) if (!p) SKIP("unknown table %d\n", table); - #ifdef IPV6 if (a[RTA_IIF]) SKIP("IIF set\n"); @@ -1008,9 +1176,12 @@ nl_parse_route(struct nlmsghdr *h, int scan) SKIP("TOS %02x\n", i->rtm_tos); #endif - if (scan && !new) + 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"); @@ -1019,6 +1190,7 @@ nl_parse_route(struct nlmsghdr *h, int scan) // if (i->rtm_scope != RT_SCOPE_UNIVERSE) // SKIP("scope %u\n", i->rtm_scope); + switch (i->rtm_protocol) { case RTPROT_UNSPEC: @@ -1033,7 +1205,7 @@ nl_parse_route(struct nlmsghdr *h, int scan) return; case RTPROT_BIRD: - if (!scan) + if (!s->scan) SKIP("echo\n"); src = KRT_SRC_BIRD; break; @@ -1045,12 +1217,14 @@ nl_parse_route(struct nlmsghdr *h, int scan) net *net = net_get(p->p.table, dst, i->rtm_dst_len); - rta ra = { - .src= p->p.main_source, - .source = RTS_INHERIT, - .scope = SCOPE_UNIVERSE, - .cast = RTC_UNICAST - }; + 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) { @@ -1058,9 +1232,9 @@ nl_parse_route(struct nlmsghdr *h, int scan) 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) + 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); @@ -1070,8 +1244,8 @@ nl_parse_route(struct nlmsghdr *h, int scan) break; } - ra.iface = if_find_by_index(oif); - if (!ra.iface) + 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); @@ -1081,39 +1255,39 @@ nl_parse_route(struct nlmsghdr *h, int scan) 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); + 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)) + if (ipa_in_net(ra->gw, IPA_NONE, 96)) return; #endif - ng = neigh_find2(&p->p, &ra.gw, ra.iface, + 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); + net->n.prefix, net->n.pxlen, ra->gw); return; } } else { - ra.dest = RTD_DEVICE; + ra->dest = RTD_DEVICE; } break; case RTN_BLACKHOLE: - ra.dest = RTD_BLACKHOLE; + ra->dest = RTD_BLACKHOLE; break; case RTN_UNREACHABLE: - ra.dest = RTD_UNREACHABLE; + ra->dest = RTD_UNREACHABLE; break; case RTN_PROHIBIT: - ra.dest = RTD_PROHIBIT; + ra->dest = RTD_PROHIBIT; break; /* FIXME: What about RTN_THROW? */ default: @@ -1121,41 +1295,30 @@ nl_parse_route(struct nlmsghdr *h, int scan) return; } - rte *e = rte_get_temp(&ra); - e->net = net; - e->u.krt.src = src; - e->u.krt.proto = i->rtm_protocol; - e->u.krt.seen = 0; - e->u.krt.best = 0; - e->u.krt.metric = 0; - - if (a[RTA_PRIORITY]) - e->u.krt.metric = rta_get_u32(a[RTA_PRIORITY]); - if (a[RTA_PREFSRC]) { ip_addr ps; memcpy(&ps, RTA_DATA(a[RTA_PREFSRC]), sizeof(ps)); ipa_ntoh(ps); - ea_list *ea = alloca(sizeof(ea_list) + sizeof(eattr)); - ea->next = ra.eattrs; - ra.eattrs = ea; + 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 = alloca(sizeof(struct adata) + sizeof(ps)); + 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 = alloca(sizeof(ea_list) + sizeof(eattr)); - ea->next = ra.eattrs; - ra.eattrs = ea; + 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; @@ -1167,7 +1330,7 @@ nl_parse_route(struct nlmsghdr *h, int scan) if (a[RTA_METRICS]) { u32 metrics[KRT_METRICS_MAX]; - ea_list *ea = alloca(sizeof(ea_list) + KRT_METRICS_MAX * sizeof(eattr)); + 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) @@ -1189,30 +1352,62 @@ nl_parse_route(struct nlmsghdr *h, int scan) if (n > 0) { - ea->next = ra.eattrs; + ea->next = ra->eattrs; ea->flags = EALF_SORTED; ea->count = n; - ra.eattrs = ea; + ra->eattrs = ea; } } - if (scan) - krt_got_route(p, e); + /* + * 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 - krt_got_route_async(p, e, new); + { + /* 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(h, 1); + nl_parse_route(&s, h); else log(L_DEBUG "nl_scan_fire: Unknown packet received (type=%d)", h->nlmsg_type); + + nl_parse_end(&s); } /* @@ -1225,12 +1420,16 @@ 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_route(h, 0); + nl_parse_begin(&s, 0, 0); + nl_parse_route(&s, h); + nl_parse_end(&s); break; case RTM_NEWLINK: case RTM_DELLINK: @@ -1353,6 +1552,7 @@ nl_open_async(void) void krt_sys_io_init(void) { + nl_linpool = lp_new(krt_pool, 4080); HASH_INIT(nl_table_map, krt_pool, 6); } |