diff options
Diffstat (limited to 'sysdep/linux')
| -rw-r--r-- | sysdep/linux/netlink.c | 54 |
1 files changed, 41 insertions, 13 deletions
diff --git a/sysdep/linux/netlink.c b/sysdep/linux/netlink.c index 6cea2fa9..279f3c9c 100644 --- a/sysdep/linux/netlink.c +++ b/sysdep/linux/netlink.c @@ -83,22 +83,26 @@ struct rtvia { /* * 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. + * 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 are just - * considered non-matching. + * 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. + * 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 @@ -348,6 +352,12 @@ static struct nl_want_attrs nexthop_attr_want4[BIRD_RTA_MAX] = { [RTA_ENCAP] = { 1, 0, 0 }, }; +static struct nl_want_attrs nexthop_attr_want6[BIRD_RTA_MAX] = { + [RTA_GATEWAY] = { 1, 1, sizeof(ip6_addr) }, + [RTA_ENCAP_TYPE]= { 1, 1, sizeof(u16) }, + [RTA_ENCAP] = { 1, 0, 0 }, +}; + static struct nl_want_attrs encap_mpls_want[BIRD_RTA_MAX] = { [RTA_DST] = { 1, 0, 0 }, }; @@ -374,6 +384,7 @@ static struct nl_want_attrs rtm_attr_want6[BIRD_RTA_MAX] = { [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_ENCAP_TYPE]= { 1, 1, sizeof(u16) }, @@ -631,7 +642,7 @@ nl_add_multipath(struct nlmsghdr *h, uint bufsize, struct nexthop *nh, int af) } static struct nexthop * -nl_parse_multipath(struct krt_proto *p, struct rtattr *ra) +nl_parse_multipath(struct krt_proto *p, struct rtattr *ra, int af) { /* Temporary buffer for multicast nexthops */ static struct nexthop *nh_buffer; @@ -670,7 +681,22 @@ nl_parse_multipath(struct krt_proto *p, struct rtattr *ra) /* Nonexistent RTNH_PAYLOAD ?? */ nl_attr_len = nh->rtnh_len - RTNH_LENGTH(0); - nl_parse_attrs(RTNH_DATA(nh), nexthop_attr_want4, a, sizeof(a)); + switch (af) + { + case AF_INET: + if (!nl_parse_attrs(RTNH_DATA(nh), nexthop_attr_want4, a, sizeof(a))) + return NULL; + break; + + case AF_INET6: + if (!nl_parse_attrs(RTNH_DATA(nh), nexthop_attr_want6, a, sizeof(a))) + return NULL; + break; + + default: + return NULL; + } + if (a[RTA_GATEWAY]) { rv->gw = rta_get_ipa(a[RTA_GATEWAY]); @@ -1520,9 +1546,9 @@ nl_parse_route(struct nl_parse_state *s, struct nlmsghdr *h) case RTN_UNICAST: ra->dest = RTD_UNICAST; - if (a[RTA_MULTIPATH] && (i->rtm_family == AF_INET)) - { - struct nexthop *nh = nl_parse_multipath(p, a[RTA_MULTIPATH]); + if (a[RTA_MULTIPATH]) + { + struct nexthop *nh = nl_parse_multipath(p, a[RTA_MULTIPATH], i->rtm_family); if (!nh) { log(L_ERR "KRT: Received strange multipath route %N", net->n.addr); @@ -1699,8 +1725,10 @@ nl_parse_route(struct nl_parse_state *s, struct nlmsghdr *h) /* * 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. + * 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 + * proper multipath updates are rejected by nl_mergable_route(), so it is + * always the first case for them. */ if (!s->net) |