tcp_info: Add and export more FreeBSD-specific fields

This change adds struct tcp_info fields corresponding to the following
struct tcpcb ones:
- snd_una
- snd_max
- rcv_numsacks
- rcv_adv
- dupacks

Note that while both tcp_fill_info() and fill_tcp_info_from_tcb() are
extended accordingly, no counterpart of rcv_numsacks is available in
the cxgbe(4) TOE PCB, though.

Sponsored by:	NetApp, Inc. (originally)

sys/dev/cxgbe/tom/t4_tom.c

@@ -730,9 +730,13 @@ fill_tcp_info_from_tcb(struct adapter *sc, uint64_t *tcb, struct tcp_info *ti)
 	ti->tcpi_snd_ssthresh = GET_TCB_FIELD(tcb, SND_SSTHRESH);
 	ti->tcpi_snd_cwnd = GET_TCB_FIELD(tcb, SND_CWND);
 	ti->tcpi_rcv_nxt = GET_TCB_FIELD(tcb, RCV_NXT);
+	ti->tcpi_rcv_adv = GET_TCB_FIELD(tcb, RCV_ADV);
+	ti->tcpi_dupacks = GET_TCB_FIELD(tcb, T_DUPACKS);
 
 	v = GET_TCB_FIELD(tcb, TX_MAX);
 	ti->tcpi_snd_nxt = v - GET_TCB_FIELD(tcb, SND_NXT_RAW);
+	ti->tcpi_snd_una = v - GET_TCB_FIELD(tcb, SND_UNA_RAW);
+	ti->tcpi_snd_max = v - GET_TCB_FIELD(tcb, SND_MAX_RAW);
 
 	/* Receive window being advertised by us. */
 	ti->tcpi_rcv_wscale = GET_TCB_FIELD(tcb, SND_SCALE);	/* Yes, SND. */

sys/netinet/tcp.h

@@ -427,8 +427,14 @@ struct tcp_info {
 	u_int32_t	tcpi_total_tlp;		/* tail loss probes sent */
 	u_int64_t	tcpi_total_tlp_bytes;	/* tail loss probe bytes sent */
 
+	u_int32_t	tcpi_snd_una;		/* Unacked seqno sent */
+	u_int32_t	tcpi_snd_max;		/* Highest seqno sent */
+	u_int32_t	tcpi_rcv_numsacks;	/* Distinct SACK blks present */
+	u_int32_t	tcpi_rcv_adv;		/* Peer advertised window */
+	u_int32_t	tcpi_dupacks;		/* Consecutive dup ACKs recvd */
+
 	/* Padding to grow without breaking ABI. */
-	u_int32_t	__tcpi_pad[19];		/* Padding. */
+	u_int32_t	__tcpi_pad[14];		/* Padding. */
 };
 
 /*

sys/netinet/tcp_usrreq.c

@@ -1591,6 +1591,11 @@ tcp_fill_info(const struct tcpcb *tp, struct tcp_info *ti)
 	ti->tcpi_snd_rexmitpack = tp->t_sndrexmitpack;
 	ti->tcpi_rcv_ooopack = tp->t_rcvoopack;
 	ti->tcpi_snd_zerowin = tp->t_sndzerowin;
+	ti->tcpi_snd_una = tp->snd_una;
+	ti->tcpi_snd_max = tp->snd_max;
+	ti->tcpi_rcv_numsacks = tp->rcv_numsacks;
+	ti->tcpi_rcv_adv = tp->rcv_adv;
+	ti->tcpi_dupacks = tp->t_dupacks;
 #ifdef TCP_OFFLOAD
 	if (tp->t_flags & TF_TOE) {
 		ti->tcpi_options |= TCPI_OPT_TOE;