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Merge commit 'e9e6baae' into HEAD

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Maria Matejka 2022-10-04 16:02:23 +02:00
commit a414ba6b97
1 changed files with 62 additions and 225 deletions
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287
sysdep/linux/netlink.c
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@ -75,51 +75,16 @@
#endif #endif
#define krt_ipv4(p) ((p)->af == AF_INET) #define krt_ipv4(p) ((p)->af == AF_INET)
#define krt_ecmp6(p) ((p)->af == AF_INET6)
const int rt_default_ecmp = 16; 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 nl_parse_state
{ {
struct krt_proto *proto;
struct linpool *pool; struct linpool *pool;
int scan; int scan;
int merge;
net_addr *net; u32 rta_flow;
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 */
}; };
/* /*
@ -1453,10 +1418,13 @@ nh_bufsize(struct nexthop_adata *nhad)
} }
static int 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; eattr *ea;
ea_list *eattrs = e->attrs; 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); int bufsize = 128 + KRT_METRICS_MAX*8 + (nh ? nh_bufsize(nh) : 0);
u32 priority = 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 */ /* For route delete, we do not specify remaining route attributes */
if (op == NL_OP_DELETE) if (op == NL_OP_DELETE)
goto dest; goto done;
/* Default scope is LINK for device routes, UNIVERSE otherwise */ /* Default scope is LINK for device routes, UNIVERSE otherwise */
if (p->af == AF_MPLS) if (p->af == AF_MPLS)
r->r.rtm_scope = RT_SCOPE_UNIVERSE; r->r.rtm_scope = RT_SCOPE_UNIVERSE;
else if (ea = ea_find(eattrs, &ea_krt_scope)) else if (ea = ea_find(eattrs, &ea_krt_scope))
r->r.rtm_scope = ea->u.data; 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 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)) if (ea = ea_find(eattrs, &ea_krt_prefsrc))
nl_add_attr_ipa(&r->h, rsize, RTA_PREFSRC, *(ip_addr *)ea->u.ptr->data); 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]) if (metrics[0])
nl_add_metrics(&r->h, rsize, metrics, KRT_METRICS_MAX); nl_add_metrics(&r->h, rsize, metrics, KRT_METRICS_MAX);
dest:
switch (dest) switch (dest)
{ {
case RTD_UNICAST: case RTD_UNICAST:
r->r.rtm_type = RTN_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); nl_add_multipath(&r->h, rsize, nh, p->af, eattrs);
else else
{ {
@ -1597,99 +1565,56 @@ dest:
bug("krt_capable inconsistent with nl_send_route"); bug("krt_capable inconsistent with nl_send_route");
} }
done:
/* Ignore missing for DELETE */ /* Ignore missing for DELETE */
return nl_exchange(&r->h, (op == NL_OP_DELETE)); return nl_exchange(&r->h, (op == NL_OP_DELETE));
} }
static inline int static inline int
nl_add_rte(struct krt_proto *p, rte *e) nl_allow_replace(struct krt_proto *p, rte *new)
{ {
ea_list *ea = e->attrs; /*
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
*/
eattr *nhea = ea_find(ea, &ea_gen_nexthop); if (krt_ipv4(p))
struct nexthop_adata *nhad = nhea ? (struct nexthop_adata *) nhea->u.ptr : NULL; return 1;
if (krt_ecmp6(p) && nhad && NEXTHOP_IS_REACHABLE(nhad) && !NEXTHOP_ONE(nhad)) eattr *nhea = ea_find(new->attrs, &ea_gen_nexthop);
{ struct nexthop_adata *nh = nhea ? (struct nexthop_adata *) nhea->u.ptr : NULL;
uint cnt = 0; int dest = nhea_dest(nhea);
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++) return (dest == RTD_UNICAST) && ipa_nonzero(nh->nh.gw);
{
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)
{
int err = 0;
/* For IPv6, we just repeatedly request DELETE until we get error */
do
err = nl_send_route(p, e, NL_OP_DELETE, RTD_NONE, NULL);
while (krt_ecmp6(p) && !err);
return err;
}
static inline int
nl_replace_rte(struct krt_proto *p, rte *e)
{
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);
}
void void
krt_replace_rte(struct krt_proto *p, const net_addr *n UNUSED, rte *new, const rte *old) krt_replace_rte(struct krt_proto *p, const net_addr *n UNUSED, rte *new, const rte *old)
{ {
int err = 0; int err = 0;
/* if (old && new && nl_allow_replace(p, 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.
*
* We do not use NL_OP_REPLACE for IPv6, as it has broken semantics for ECMP
* and with some kernel versions ECMP replace crashes kernel. Would need more
* testing and checks for kernel versions.
*
* For IPv6, we use NL_OP_DELETE and then NL_OP_ADD. We also do not trust the
* old route value, so we do not try to optimize IPv6 ECMP reconfigurations.
*/
if (krt_ipv4(p) && old && new)
{ {
err = nl_replace_rte(p, new); err = nl_send_route(p, new, NL_OP_REPLACE);
} }
else else
{ {
if (old) if (old)
nl_delete_rte(p, old); nl_send_route(p, old, NL_OP_DELETE);
if (new) if (new)
err = nl_add_rte(p, new); err = nl_send_route(p, new, NL_OP_ADD);
} }
if (new) 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 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) #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)); 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_list *ra = NULL;
ea_set_attr_u32(&ra, &ea_gen_source, 0, RTS_INHERIT); 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]) if (a[RTA_FLOW])
s->rta_flow = rta_get_u32(a[RTA_FLOW]); s->rta_flow = rta_get_u32(a[RTA_FLOW]);
@ -2012,6 +1874,9 @@ nl_parse_route(struct nl_parse_state *s, struct nlmsghdr *h)
return; 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) if (i->rtm_scope != def_scope)
ea_set_attr(&ra, ea_set_attr(&ra,
EA_LITERAL_EMBEDDED(&ea_krt_scope, 0, i->rtm_scope)); EA_LITERAL_EMBEDDED(&ea_krt_scope, 0, i->rtm_scope));
@ -2044,56 +1909,27 @@ nl_parse_route(struct nl_parse_state *s, struct nlmsghdr *h)
EA_LITERAL_EMBEDDED(&ea_krt_metrics[t], 0, metrics[t])); EA_LITERAL_EMBEDDED(&ea_krt_metrics[t], 0, metrics[t]));
} }
/* rte e0 = {
* Ideally, now we would send the received route to the rest of kernel code. .net = net,
* But IPv6 ECMP routes before 4.11 are sent as a sequence of routes, so we .attrs = ra,
* postpone it and merge next hops until the end of the sequence. Note that };
* when doing merging of next hops, we expect the new route to be unipath.
* Otherwise, we ignore additional next hops in nexthop_insert().
*/
if (!s->net) if (s->scan)
{ krt_got_route(p, &e0, krt_src);
/* 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;
}
else else
{ krt_got_route_async(p, &e0, new, krt_src);
/* 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) lp_flush(s->pool);
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);
}
} }
void void
krt_do_scan(struct krt_proto *p) krt_do_scan(struct krt_proto *p)
{ {
struct nlmsghdr *h; struct nl_parse_state s = {
struct nl_parse_state s; .proto = p,
.pool = nl_linpool,
nl_parse_begin(&s, 1); .scan = 1,
};
/* Table-specific scan or shared scan */ /* Table-specific scan or shared scan */
if (p) if (p)
@ -2101,6 +1937,7 @@ krt_do_scan(struct krt_proto *p)
else else
nl_request_dump_route(AF_UNSPEC, 0); nl_request_dump_route(AF_UNSPEC, 0);
struct nlmsghdr *h;
while (h = nl_get_scan()) while (h = nl_get_scan())
{ {
if (h->nlmsg_type == RTM_NEWROUTE || h->nlmsg_type == RTM_DELROUTE) if (h->nlmsg_type == RTM_NEWROUTE || h->nlmsg_type == RTM_DELROUTE)
@ -2108,8 +1945,6 @@ krt_do_scan(struct krt_proto *p)
else else
log(L_DEBUG "nl_scan_fire: Unknown packet received (type=%d)", h->nlmsg_type); log(L_DEBUG "nl_scan_fire: Unknown packet received (type=%d)", h->nlmsg_type);
} }
nl_parse_end(&s);
} }
/* /*
@ -2124,16 +1959,18 @@ static struct config *nl_last_config; /* For tracking changes to nl_async_bufsiz
static void static void
nl_async_msg(struct nlmsghdr *h) 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) switch (h->nlmsg_type)
{ {
case RTM_NEWROUTE: case RTM_NEWROUTE:
case RTM_DELROUTE: case RTM_DELROUTE:
DBG("KRT: Received async route notification (%d)\n", h->nlmsg_type); DBG("KRT: Received async route notification (%d)\n", h->nlmsg_type);
nl_parse_begin(&s, 0);
nl_parse_route(&s, h); nl_parse_route(&s, h);
nl_parse_end(&s);
break; break;
case RTM_NEWLINK: case RTM_NEWLINK:
case RTM_DELLINK: case RTM_DELLINK: