Fix netstat output of uses of current SYN cache left.

TCP syn cache variable scs_use is basically counting packet insertions
into syn cache.  Prefer type long to exclude overflow on fast
machines.  Due to counting downwards from a limit, it can become
negative.  Copy it out as tcps_sc_uses_left via sysctl, and print
it as signed long long integer.

OK mvs@

diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h
index be7e986..912381b 100644 (file)
--- a/sys/netinet/tcp_var.h
+++ b/sys/netinet/tcp_var.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: tcp_var.h,v 1.170 2023/08/28 14:50:02 bluhm Exp $     */
+/*     $OpenBSD: tcp_var.h,v 1.171 2023/09/04 23:00:36 bluhm Exp $     */
 /*     $NetBSD: tcp_var.h,v 1.17 1996/02/13 23:44:24 christos Exp $    */
 
 /*
@@ -288,9 +288,9 @@ struct syn_cache_head {
 
 struct syn_cache_set {
        struct          syn_cache_head *scs_buckethead;
+       long            scs_use;
        int             scs_size;
        int             scs_count;
-       int             scs_use;
        u_int32_t       scs_random[5];
 };
 
@@ -430,7 +430,7 @@ struct      tcpstat {
        u_int64_t tcps_sc_entry_limit;  /* limit of syn cache entries */
        u_int64_t tcps_sc_bucket_maxlen;/* maximum # of entries in any bucket */
        u_int64_t tcps_sc_bucket_limit; /* limit of syn cache bucket list */
-       u_int64_t tcps_sc_uses_left;    /* use counter of current syn cache */
+       int64_t tcps_sc_uses_left;      /* use counter of current syn cache */
 
        u_int64_t tcps_conndrained;     /* # of connections drained */
 

diff --git a/usr.bin/netstat/inet.c b/usr.bin/netstat/inet.c
index a677d22..94089d5 100644 (file)
--- a/usr.bin/netstat/inet.c
+++ b/usr.bin/netstat/inet.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: inet.c,v 1.178 2023/07/07 09:15:13 yasuoka Exp $      */
+/*     $OpenBSD: inet.c,v 1.179 2023/09/04 23:00:36 bluhm Exp $        */
 /*     $NetBSD: inet.c,v 1.14 1995/10/03 21:42:37 thorpej Exp $        */
 
 /*
@@ -498,7 +498,7 @@ tcp_stats(char *name)
            "\t%llu entr%s in current SYN cache, limit is %llu\n");
        p2b(tcps_sc_bucket_maxlen, tcps_sc_bucket_limit,
            "\t%llu longest bucket length in current SYN cache, limit is %llu\n");
-       p(tcps_sc_uses_left, "\t%llu use%s of current SYN cache left\n");
+       p(tcps_sc_uses_left, "\t%lld use%s of current SYN cache left\n");
 
        p(tcps_sack_recovery_episode, "\t%llu SACK recovery episode%s\n");
        p(tcps_sack_rexmits,