Add RTA_DEL_REASON and enum rt_del_reason to the rtnetlink uAPI, and add ip6_del_rt_reason(), which takes the reason a route is being deleted. It has no skip_notify argument: a caller that records a deletion reason wants the notification that carries it.
The reason is unused for now. Subsequent patches propagate it to the deletion path and report it on RTM_DELROUTE. Signed-off-by: Yuyang Huang <[email protected]> --- include/net/ip6_route.h | 2 ++ include/uapi/linux/rtnetlink.h | 25 +++++++++++++++++++++++++ net/ipv6/route.c | 8 ++++++++ 3 files changed, 35 insertions(+) diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h index 09ffe0f13ce7..cc045705862d 100644 --- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h @@ -126,6 +126,8 @@ int ipv6_route_ioctl(struct net *net, unsigned int cmd, int ip6_route_add(struct fib6_config *cfg, gfp_t gfp_flags, struct netlink_ext_ack *extack); int ip6_ins_rt(struct net *net, struct fib6_info *f6i); +int ip6_del_rt_reason(struct net *net, struct fib6_info *f6i, + enum rt_del_reason del_reason); #if IS_ENABLED(CONFIG_IPV6) int ip6_del_rt(struct net *net, struct fib6_info *f6i, bool skip_notify); #else diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h index 27265fd31e5f..3988b51db539 100644 --- a/include/uapi/linux/rtnetlink.h +++ b/include/uapi/linux/rtnetlink.h @@ -399,6 +399,7 @@ enum rtattr_type_t { RTA_DPORT, RTA_NH_ID, RTA_FLOWLABEL, + RTA_DEL_REASON, __RTA_MAX }; @@ -407,6 +408,30 @@ enum rtattr_type_t { #define RTM_RTA(r) ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct rtmsg)))) #define RTM_PAYLOAD(n) NLMSG_PAYLOAD(n,sizeof(struct rtmsg)) +/* RTA_DEL_REASON: why the kernel deleted the route. u32. + * Emitted only on RTM_DELROUTE notifications, and only when the deletion + * path records a cause. Absence means either an older kernel or a + * deletion path that does not (yet) record its cause - consumers must + * treat "absent" and "unspec" identically. New causes may be appended. + * Currently only IPv6 deletion paths record a cause. + * + * The attribute is notification-only: the kernel rejects it in + * requests, so a notification must not be echoed back verbatim. + * + * The value space is family-agnostic: a value must never be + * reinterpreted per address family. A cause that only one family can + * produce still gets its own value rather than reusing another + * family's. + */ +enum rt_del_reason { + RT_DEL_REASON_UNSPEC, /* cause not recorded */ + RT_DEL_REASON_EXPIRED, /* RTF_EXPIRES lifetime ran out (GC) */ + RT_DEL_REASON_RA_WITHDRAWN, /* zero-lifetime RA / PIO / RIO */ + __RT_DEL_REASON_MAX +}; + +#define RT_DEL_REASON_MAX (__RT_DEL_REASON_MAX - 1) + /* RTM_MULTIPATH --- array of struct rtnexthop. * * "struct rtnexthop" describes all necessary nexthop information, diff --git a/net/ipv6/route.c b/net/ipv6/route.c index fc42d67e5822..ca374b056f5a 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -4004,6 +4004,14 @@ int ip6_del_rt(struct net *net, struct fib6_info *rt, bool skip_notify) return __ip6_del_rt(rt, &info); } +int ip6_del_rt_reason(struct net *net, struct fib6_info *rt, + enum rt_del_reason del_reason) +{ + struct nl_info info = { .nl_net = net }; + + return __ip6_del_rt(rt, &info); +} + static int __ip6_del_rt_siblings(struct fib6_info *rt, struct fib6_config *cfg) { struct nl_info *info = &cfg->fc_nlinfo; -- 2.43.0
