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Kernel: Fix handling of krt_realm with ECMP routes

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For ECMP routes, RTA_FLOW attribute must be set per-nexthop, not
per-route. Our corresponding krt_realm attribute is per-route.

Thanks to Mikhail Petrov for the bugreport.
This commit is contained in:
Ondrej Zajicek (work) 2021-01-06 05:25:59 +01:00
parent 455c13dc99
commit 21f9acd2a0
1 changed files with 23 additions and 4 deletions
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27
sysdep/linux/netlink.c
View file

@ -113,6 +113,8 @@ struct nl_parse_state
u8 krt_type;
u8 krt_proto;
u32 krt_metric;
u32 rta_flow; /* Used during parsing */
};
/*
@ -345,6 +347,7 @@ static struct nl_want_attrs ifa_attr_want6[BIRD_IFA_MAX] = {
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 },
};
@ -352,6 +355,7 @@ static struct nl_want_attrs nexthop_attr_want4[BIRD_RTA_MAX] = {
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 },
};
@ -647,9 +651,10 @@ nl_add_nexthop(struct nlmsghdr *h, uint bufsize, struct nexthop *nh, int af UNUS
}
static void
nl_add_multipath(struct nlmsghdr *h, uint bufsize, struct nexthop *nh, int af)
nl_add_multipath(struct nlmsghdr *h, uint bufsize, struct nexthop *nh, int af, ea_list *eattrs)
{
struct rtattr *a = nl_open_attr(h, bufsize, RTA_MULTIPATH);
eattr *flow = ea_find(eattrs, EA_KRT_REALM);
for (; nh; nh = nh->next)
{
@ -664,6 +669,11 @@ nl_add_multipath(struct nlmsghdr *h, uint bufsize, struct nexthop *nh, int 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);
}
@ -727,6 +737,9 @@ nl_parse_multipath(struct nl_parse_state *s, struct krt_proto *p, struct rtattr
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]);
@ -1339,7 +1352,7 @@ dest:
case RTD_UNICAST:
r->r.rtm_type = RTN_UNICAST;
if (nh->next && !krt_ecmp6(p))
nl_add_multipath(&r->h, rsize, nh, p->af);
nl_add_multipath(&r->h, rsize, nh, p->af, eattrs);
else
{
nl_add_attr_u32(&r->h, rsize, RTA_OIF, nh->iface->index);
@ -1647,6 +1660,11 @@ nl_parse_route(struct nl_parse_state *s, struct nlmsghdr *h)
ra->source = RTS_INHERIT;
ra->scope = SCOPE_UNIVERSE;
if (a[RTA_FLOW])
s->rta_flow = rta_get_u32(a[RTA_FLOW]);
else
s->rta_flow = 0;
switch (i->rtm_type)
{
case RTN_UNICAST:
@ -1773,7 +1791,8 @@ nl_parse_route(struct nl_parse_state *s, struct nlmsghdr *h)
ea->attrs[0].u.ptr = ad;
}
if (a[RTA_FLOW])
/* Can be set per-route or per-nexthop */
if (s->rta_flow)
{
ea_list *ea = lp_alloc(s->pool, sizeof(ea_list) + sizeof(eattr));
ea->next = ra->eattrs;
@ -1783,7 +1802,7 @@ nl_parse_route(struct nl_parse_state *s, struct nlmsghdr *h)
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]);
ea->attrs[0].u.data = s->rta_flow;
}
if (a[RTA_METRICS])