illumos gate

While testing the fix for #13839, I noticed that the UDP output looked wrong:

UDP: IPv4
   Local Address        Remote Address      User    Pid      Command       State
-------------------- -------------------- -------- ------ -------------- ----------
...
127.0.0.1.56731      127.0.0.1.56731      root        734 xxxxd       Connected
127.0.0.1.40535      127.0.0.1.40535      root        609 yyyyd        Connected
...

Note that the src and dest IP+port are identical.

The reason is that when printing UDP sockets, the same buffer is reused when formatting the local and remote connection information (unlike TCP which uses a separate buffer for local and remote):

static boolean_t
udp_report_item_v4(const mib2_udpEntry_t *ude, boolean_t first,
    const mib2_transportMLPEntry_t *attr, const mib2_socketInfoEntry_t *sie)
{
        char    *leadin;
        char    lname[MAXHOSTNAMELEN + MAXHOSTNAMELEN + 1];
                        /* hostname + portname */
...
        if (asprintf(&leadin,
            UDP_V4_LOCAL_F " " UDP_V4_REMOTE_F " ",
            pr_ap(ude->udpLocalAddress, ude->udpLocalPort, "udp",
            lname, sizeof (lname)),
            ude->udpEntryInfo.ue_state == MIB2_UDP_connected ?
            pr_ap(ude->udpEntryInfo.ue_RemoteAddress,
            ude->udpEntryInfo.ue_RemotePort, "udp", lname, sizeof (lname)) :
            "") == -1) {
                fatal(1, "Out of memory");
        }
...

Note that lname is used both for the remote address and local address. Compare that to TCP:

static boolean_t
tcp_report_item_v4(const mib2_tcpConnEntry_t *tp, boolean_t first,
    const mib2_transportMLPEntry_t *attr, const mib2_socketInfoEntry_t *sie)
{
        /*
         * lname and fname below are for the hostname as well as the portname
         * There is no limit on portname length so we assume MAXHOSTNAMELEN
         * as the limit
         */
        char    lname[MAXHOSTNAMELEN + MAXHOSTNAMELEN + 1];
        char    fname[MAXHOSTNAMELEN + MAXHOSTNAMELEN + 1];
...
               (void) printf(
                    TCP_V4_LOCAL_F " " TCP_V4_REMOTE_F " " 
                    TCP_V4_SWIND_F " " TCP_V4_SENDQ_F " " 
                    TCP_V4_RWIND_F " " TCP_V4_RECVQ_F " %s\n",
                    pr_ap(tp->tcpConnLocalAddress,
                    tp->tcpConnLocalPort, "tcp", lname, sizeof (lname)),
                    pr_ap(tp->tcpConnRemAddress,
                    tp->tcpConnRemPort, "tcp", fname, sizeof (fname)),
                    tp->tcpConnEntryInfo.ce_swnd,
                    (sq >= 0) ? sq : 0,
                    tp->tcpConnEntryInfo.ce_rwnd,
                    (rq >= 0) ? rq : 0,
                    mitcp_state(tp->tcpConnEntryInfo.ce_state, attr));

The IPv6 versions of these respective functions have a similar form. The fix is to use a separate buffer for the remote address when printing UDP sockets.