ipv6: add ip6_del_rt_reason()

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.

Yuyang Huang committed 3 months ago

Commit cc17e381 parent f6057f03 files · +35 −0Browse files

Unified · Split

3 files

include/net/ip6_route.h +2 −0
include/uapi/linux/rtnetlink.h +25 −0
net/ipv6/route.c +8 −0

include/net/ip6_route.h+2−0

@@ -126,6 +126,8 @@ int ipv6_route_ioctl(struct net *net, unsigned int cmd, · 125 unmodified lines
126	126	int ip6_route_add(struct fib6_config *cfg, gfp_t gfp_flags,
127	127	struct netlink_ext_ack *extack);
128	128	int ip6_ins_rt(struct net net, struct fib6_info f6i);
	129	+int ip6_del_rt_reason(struct net net, struct fib6_info f6i,
	130	+ enum rt_del_reason del_reason);
129	131	#if IS_ENABLED(CONFIG_IPV6)
130	132	int ip6_del_rt(struct net net, struct fib6_info f6i, bool skip_notify);
131	133	#else

include/uapi/linux/rtnetlink.h+25−0

@@ -399,6 +399,7 @@ enum rtattr_type_t { · 398 unmodified lines
399	399	RTA_DPORT,
400	400	RTA_NH_ID,
401	401	RTA_FLOWLABEL,
	402	+ RTA_DEL_REASON,
402	403	__RTA_MAX
403	404	};
404	405
@@ -407,6 +408,30 @@ enum rtattr_type_t { · 2 unmodified lines
407	408	#define RTM_RTA(r) ((struct rtattr)(((char)(r)) + NLMSG_ALIGN(sizeof(struct rtmsg))))
408	409	#define RTM_PAYLOAD(n) NLMSG_PAYLOAD(n,sizeof(struct rtmsg))
409	410
	411	+/* RTA_DEL_REASON: why the kernel deleted the route. u32.
	412	+ * Emitted only on RTM_DELROUTE notifications, and only when the deletion
	413	+ * path records a cause. Absence means either an older kernel or a
	414	+ * deletion path that does not (yet) record its cause - consumers must
	415	+ * treat "absent" and "unspec" identically. New causes may be appended.
	416	+ * Currently only IPv6 deletion paths record a cause.
	417	+ *
	418	+ * The attribute is notification-only: the kernel rejects it in
	419	+ * requests, so a notification must not be echoed back verbatim.
	420	+ *
	421	+ * The value space is family-agnostic: a value must never be
	422	+ * reinterpreted per address family. A cause that only one family can
	423	+ * produce still gets its own value rather than reusing another
	424	+ * family's.
	425	+ */
	426	+enum rt_del_reason {
	427	+ RT_DEL_REASON_UNSPEC, /* cause not recorded */
	428	+ RT_DEL_REASON_EXPIRED, /* RTF_EXPIRES lifetime ran out (GC) */
	429	+ RT_DEL_REASON_RA_WITHDRAWN, /* zero-lifetime RA / PIO / RIO */
	430	+ __RT_DEL_REASON_MAX
	431	+};
	432	+
	433	+#define RT_DEL_REASON_MAX (__RT_DEL_REASON_MAX - 1)
	434	+
410	435	/* RTM_MULTIPATH --- array of struct rtnexthop.
411	436	*
412	437	* "struct rtnexthop" describes all necessary nexthop information,

net/ipv6/route.c+8−0

@@ -4004,6 +4004,14 @@ int ip6_del_rt(struct net net, struct fib6_info rt, bool skip_notify) · 4003 unmodified lines
4004	4004	return __ip6_del_rt(rt, &info);
4005	4005	}
4006	4006
	4007	+int ip6_del_rt_reason(struct net net, struct fib6_info rt,
	4008	+ enum rt_del_reason del_reason)
	4009	+{
	4010	+ struct nl_info info = { .nl_net = net };
	4011	+
	4012	+ return __ip6_del_rt(rt, &info);
	4013	+}
	4014	+
4007	4015	static int __ip6_del_rt_siblings(struct fib6_info rt, struct fib6_config cfg)
4008	4016	{
4009	4017	struct nl_info *info = &cfg->fc_nlinfo;