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-rw-r--r--sysdep/linux/netlink.c286
1 files changed, 60 insertions, 226 deletions
diff --git a/sysdep/linux/netlink.c b/sysdep/linux/netlink.c
index 099ae6e9..94a37a73 100644
--- a/sysdep/linux/netlink.c
+++ b/sysdep/linux/netlink.c
@@ -75,51 +75,16 @@
#endif
#define krt_ipv4(p) ((p)->af == AF_INET)
-#define krt_ecmp6(p) ((p)->af == AF_INET6)
const int rt_default_ecmp = 16;
-/*
- * Structure nl_parse_state keeps state of received route processing. Ideally,
- * we could just independently parse received Netlink messages and immediately
- * propagate received routes to the rest of BIRD, but older Linux kernel (before
- * version 4.11) represents and announces IPv6 ECMP routes not as one route with
- * multiple next hops (like RTA_MULTIPATH in IPv4 ECMP), but as a sequence of
- * routes with the same prefix. More recent kernels work as with IPv4.
- *
- * Therefore, BIRD keeps currently processed route in nl_parse_state structure
- * and postpones its propagation until we expect it to be final; i.e., when
- * non-matching route is received or when the scan ends. When another matching
- * route is received, it is merged with the already processed route to form an
- * ECMP route. Note that merging is done only for IPv6 (merge == 1), but the
- * postponing is done in both cases (for simplicity). All IPv4 routes or IPv6
- * routes with RTA_MULTIPATH set are just considered non-matching.
- *
- * This is ignored for asynchronous notifications (every notification is handled
- * as a separate route). It is not an issue for our routes, as we ignore such
- * notifications anyways. But importing alien IPv6 ECMP routes does not work
- * properly with older kernels.
- *
- * Whatever the kernel version is, IPv6 ECMP routes are sent as multiple routes
- * for the same prefix.
- */
-
struct nl_parse_state
{
+ struct krt_proto *proto;
struct linpool *pool;
int scan;
- int merge;
- net_addr *net;
- ea_list *attrs;
- struct krt_proto *proto;
- s8 new;
- s8 krt_src;
- u8 krt_type;
- u8 krt_proto;
- u32 krt_metric;
-
- u32 rta_flow; /* Used during parsing */
+ u32 rta_flow;
};
/*
@@ -1453,10 +1418,13 @@ nh_bufsize(struct nexthop_adata *nhad)
}
static int
-nl_send_route(struct krt_proto *p, const rte *e, int op, int dest, struct nexthop_adata *nh)
+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;
@@ -1534,15 +1502,17 @@ nl_send_route(struct krt_proto *p, const rte *e, int op, int dest, struct nextho
/* For route delete, we do not specify remaining route attributes */
if (op == NL_OP_DELETE)
- goto dest;
+ 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 = (dest == RTD_UNICAST && ipa_zero(nh->nh.gw)) ? RT_SCOPE_LINK : RT_SCOPE_UNIVERSE;
+ 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);
@@ -1565,13 +1535,11 @@ nl_send_route(struct krt_proto *p, const rte *e, int op, int dest, struct nextho
if (metrics[0])
nl_add_metrics(&r->h, rsize, metrics, KRT_METRICS_MAX);
-
-dest:
switch (dest)
{
case RTD_UNICAST:
r->r.rtm_type = RTN_UNICAST;
- if (!NEXTHOP_ONE(nh) && !krt_ecmp6(p))
+ if (!NEXTHOP_ONE(nh))
nl_add_multipath(&r->h, rsize, nh, p->af, eattrs);
else
{
@@ -1597,99 +1565,56 @@ dest:
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_add_rte(struct krt_proto *p, rte *e)
-{
- ea_list *ea = e->attrs;
- int err = 0;
-
- eattr *nhea = ea_find(ea, &ea_gen_nexthop);
- struct nexthop_adata *nhad = nhea ? (struct nexthop_adata *) nhea->u.ptr : NULL;
-
- if (krt_ecmp6(p) && nhad && NEXTHOP_IS_REACHABLE(nhad) && !NEXTHOP_ONE(nhad))
- {
- uint cnt = 0;
- NEXTHOP_WALK(nh, nhad)
- {
- struct {
- struct nexthop_adata nhad;
- u32 labels[MPLS_MAX_LABEL_STACK];
- } nhx;
- memcpy(&nhx.nhad.nh, nh, NEXTHOP_SIZE(nh));
- nhx.nhad.ad.length = (void *) NEXTHOP_NEXT(&nhx.nhad.nh) - (void *) nhx.nhad.ad.data;
-
- if (!cnt++)
- {
- err = nl_send_route(p, e, NL_OP_ADD, RTD_UNICAST, &nhx.nhad);
- if (err < 0)
- return err;
- }
- else
- err += nl_send_route(p, e, NL_OP_APPEND, RTD_UNICAST, &nhx.nhad);
- }
-
- return err;
- }
-
- return nl_send_route(p, e, NL_OP_ADD,
- NEXTHOP_IS_REACHABLE(nhad) ? RTD_UNICAST : nhad->dest, nhad);
-}
-
-static inline int
-nl_delete_rte(struct krt_proto *p, const rte *e)
+nl_allow_replace(struct krt_proto *p, rte *new)
{
- int err = 0;
+ /*
+ * We use NL_OP_REPLACE for IPv4, it has an issue with not checking for
+ * matching rtm_protocol, but that is OK when dedicated priority is used.
+ *
+ * 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
+ */
- /* For IPv6, we just repeatedly request DELETE until we get error */
- do
- err = nl_send_route(p, e, NL_OP_DELETE, RTD_NONE, NULL);
- while (krt_ecmp6(p) && !err);
+ if (krt_ipv4(p))
+ return 1;
- return err;
-}
+ 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);
-static inline int
-nl_replace_rte(struct krt_proto *p, rte *e)
-{
- eattr *nhea = ea_find(e->attrs, &ea_gen_nexthop);
- struct nexthop_adata *nhad = nhea ? (struct nexthop_adata *) nhea->u.ptr : NULL;
- return nl_send_route(p, e, NL_OP_REPLACE,
- NEXTHOP_IS_REACHABLE(nhad) ? RTD_UNICAST : nhad->dest, nhad);
+ 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;
- /*
- * We use NL_OP_REPLACE for IPv4, it has an issue with not checking for
- * matching rtm_protocol, but that is OK when dedicated priority is used.
- *
- * We do not use NL_OP_REPLACE for IPv6, as it has broken semantics for ECMP
- * and with some kernel versions ECMP replace crashes kernel. Would need more
- * testing and checks for kernel versions.
- *
- * For IPv6, we use NL_OP_DELETE and then NL_OP_ADD. We also do not trust the
- * old route value, so we do not try to optimize IPv6 ECMP reconfigurations.
- */
-
- if (krt_ipv4(p) && old && new)
+ if (old && new && nl_allow_replace(p, new))
{
- err = nl_replace_rte(p, new);
+ err = nl_send_route(p, new, NL_OP_REPLACE);
}
else
{
if (old)
- nl_delete_rte(p, old);
+ nl_send_route(p, old, NL_OP_DELETE);
if (new)
- err = nl_add_rte(p, new);
+ err = nl_send_route(p, new, NL_OP_ADD);
}
if (new)
@@ -1701,68 +1626,6 @@ krt_replace_rte(struct krt_proto *p, const net_addr *n UNUSED, rte *new, const r
}
}
-static int
-nl_mergable_route(struct nl_parse_state *s, const net_addr *net, struct krt_proto *p, uint priority, uint krt_type, uint rtm_family)
-{
- /* Route merging is used for IPv6 scans */
- if (!s->scan || (rtm_family != AF_INET6))
- return 0;
-
- /* Saved and new route must have same network, proto/table, and priority */
- if ((s->net != net) || (s->proto != p) || (s->krt_metric != priority))
- return 0;
-
- /* Both must be regular unicast routes */
- if ((s->krt_type != RTN_UNICAST) || (krt_type != RTN_UNICAST))
- return 0;
-
- return 1;
-}
-
-static void
-nl_announce_route(struct nl_parse_state *s)
-{
- rte e0 = {
- .attrs = s->attrs,
- .net = s->net,
- };
-
- EA_LOCAL_LIST(2) ea = {
- .l = { .count = 2, .next = e0.attrs },
- .a = {
- EA_LITERAL_EMBEDDED(&ea_krt_source, 0, s->krt_proto),
- EA_LITERAL_EMBEDDED(&ea_krt_metric, 0, s->krt_metric),
- },
- };
-
- e0.attrs = &ea.l;
-
- if (s->scan)
- krt_got_route(s->proto, &e0, s->krt_src);
- else
- krt_got_route_async(s->proto, &e0, s->new, s->krt_src);
-
- s->net = NULL;
- s->attrs = NULL;
- s->proto = NULL;
- lp_flush(s->pool);
-}
-
-static inline void
-nl_parse_begin(struct nl_parse_state *s, int scan)
-{
- memset(s, 0, sizeof (struct nl_parse_state));
- s->pool = nl_linpool;
- s->scan = scan;
-}
-
-static inline void
-nl_parse_end(struct nl_parse_state *s)
-{
- if (s->net)
- nl_announce_route(s);
-}
-
#define SKIP0(ARG, ...) do { DBG("KRT: Ignoring route - " ARG, ##__VA_ARGS__); return; } while(0)
#define SKIP(ARG, ...) do { DBG("KRT: Ignoring route %N - " ARG, &dst, ##__VA_ARGS__); return; } while(0)
@@ -1898,11 +1761,10 @@ nl_parse_route(struct nl_parse_state *s, struct nlmsghdr *h)
net6_prefix(&src), net6_pxlen(&src));
}
- if (s->net && !nl_mergable_route(s, net, p, priority, i->rtm_type, i->rtm_family))
- nl_announce_route(s);
-
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]);
@@ -2044,56 +1906,27 @@ nl_parse_route(struct nl_parse_state *s, struct nlmsghdr *h)
EA_LITERAL_EMBEDDED(&ea_krt_metrics[t], 0, metrics[t]));
}
- /*
- * Ideally, now we would send the received route to the rest of kernel code.
- * But IPv6 ECMP routes before 4.11 are sent as a sequence of routes, so we
- * postpone it and merge next hops until the end of the sequence. Note that
- * when doing merging of next hops, we expect the new route to be unipath.
- * Otherwise, we ignore additional next hops in nexthop_insert().
- */
+ rte e0 = {
+ .net = net,
+ .attrs = ra,
+ };
- if (!s->net)
- {
- /* Store the new route */
- s->net = lp_alloc(s->pool, net->length);
- net_copy(s->net, net);
-
- ea_set_attr_data(&ra, &ea_gen_nexthop, 0,
- nhad.ad.data, nhad.ad.length);
-
- s->attrs = ra;
- s->proto = p;
- s->new = new;
- s->krt_src = krt_src;
- s->krt_type = i->rtm_type;
- s->krt_proto = i->rtm_protocol;
- s->krt_metric = priority;
- }
+ if (s->scan)
+ krt_got_route(p, &e0, krt_src);
else
- {
- /* Merge next hops with the stored route */
- eattr *nhea = ea_find(s->attrs, &ea_gen_nexthop);
- struct nexthop_adata *nhad_old = nhea ? (struct nexthop_adata *) nhea->u.ptr : NULL;
-
- if (nhad_old)
- ea_set_attr(&s->attrs,
- EA_LITERAL_DIRECT_ADATA(&ea_gen_nexthop, 0,
- &(nexthop_merge(nhad_old, &nhad.nhad,
- KRT_CF->merge_paths, s->pool)->ad)
- ));
- else
- ea_set_attr_data(&s->attrs, &ea_gen_nexthop, 0,
- nhad.ad.data, nhad.ad.length);
- }
+ krt_got_route_async(p, &e0, new, krt_src);
+
+ lp_flush(s->pool);
}
void
krt_do_scan(struct krt_proto *p)
{
- struct nlmsghdr *h;
- struct nl_parse_state s;
-
- nl_parse_begin(&s, 1);
+ struct nl_parse_state s = {
+ .proto = p,
+ .pool = nl_linpool,
+ .scan = 1,
+ };
/* Table-specific scan or shared scan */
if (p)
@@ -2101,6 +1934,7 @@ krt_do_scan(struct krt_proto *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)
@@ -2108,8 +1942,6 @@ krt_do_scan(struct krt_proto *p)
else
log(L_DEBUG "nl_scan_fire: Unknown packet received (type=%d)", h->nlmsg_type);
}
-
- nl_parse_end(&s);
}
/*
@@ -2124,16 +1956,18 @@ static struct config *nl_last_config; /* For tracking changes to nl_async_bufsiz
static void
nl_async_msg(struct nlmsghdr *h)
{
- struct nl_parse_state s;
+ 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_begin(&s, 0);
nl_parse_route(&s, h);
- nl_parse_end(&s);
break;
case RTM_NEWLINK:
case RTM_DELLINK:
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-02 22:48:46 +0000