[PATCH] rtnetlink.7: Document struct ifa_cacheinfo

[Alex Henrie <alexhenrie24@gmail.com>]

struct ifa_cacheinfo contains the address's creation time, update time,
preferred lifetime, and valid lifetime. See
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/if_addr.h?h=v6.11#n60

Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
---
 man/man7/rtnetlink.7 | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/man/man7/rtnetlink.7 b/man/man7/rtnetlink.7
index 86ed459bb..b05654315 100644
--- a/man/man7/rtnetlink.7
+++ b/man/man7/rtnetlink.7
@@ -176,7 +176,15 @@ IFA_BROADCAST:raw protocol address:broadcast address
 IFA_ANYCAST:raw protocol address:anycast address
 IFA_CACHEINFO:struct ifa_cacheinfo:Address information
 .TE
-.\" FIXME Document struct ifa_cacheinfo
+.IP
+.EX
+struct ifa_cacheinfo {
+    __u32 ifa_prefered; /* Preferred lifetime in seconds, -1 = forever */
+    __u32 ifa_valid;    /* Valid lifetime in seconds, -1 = forever */
+    __u32 cstamp;       /* Creation timestamp in hundredths of seconds */
+    __u32 tstamp;       /* Update timestamp in hundredths of seconds */
+};
+.EE
 .TP
 .B RTM_NEWROUTE
 .TQ
-- 
2.47.0