IPVS: Add persistence engine data to /proc/net/ip_vs_conn

This shouldn't break compatibility with userspace as the new data
is at the end of the line.

I have confirmed that this doesn't break ipvsadm, the main (only?)
user-space user of this data.

Signed-off-by: Simon Horman <horms@verge.net.au>
Acked-by: Julian Anastasov <ja@ssi.bg>

include/net/ip_vs.h

@@ -572,6 +572,7 @@ struct ip_vs_pe {
 			 struct ip_vs_conn *ct);
 	u32 (*hashkey_raw)(const struct ip_vs_conn_param *p, u32 initval,
 			   bool inverse);
+	int (*show_pe_data)(const struct ip_vs_conn *cp, char *buf);
 };
 
 /*

net/netfilter/ipvs/ip_vs_conn.c

@@ -950,30 +950,45 @@ static int ip_vs_conn_seq_show(struct seq_file *seq, void *v)
 
 	if (v == SEQ_START_TOKEN)
 		seq_puts(seq,
-   "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Expires\n");
+   "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Expires PEName PEData\n");
 	else {
 		const struct ip_vs_conn *cp = v;
+		char pe_data[IP_VS_PENAME_MAXLEN + IP_VS_PEDATA_MAXLEN + 3];
+		size_t len = 0;
+
+		if (cp->dest && cp->dest->svc->pe &&
+		    cp->dest->svc->pe->show_pe_data) {
+			pe_data[0] = ' ';
+			len = strlen(cp->dest->svc->pe->name);
+			memcpy(pe_data + 1, cp->dest->svc->pe->name, len);
+			pe_data[len + 1] = ' ';
+			len += 2;
+			len += cp->dest->svc->pe->show_pe_data(cp,
+							       pe_data + len);
+		}
+		pe_data[len] = '\0';
 
 #ifdef CONFIG_IP_VS_IPV6
 		if (cp->af == AF_INET6)
-			seq_printf(seq, "%-3s %pI6 %04X %pI6 %04X %pI6 %04X %-11s %7lu\n",
+			seq_printf(seq, "%-3s %pI6 %04X %pI6 %04X "
+				"%pI6 %04X %-11s %7lu%s\n",
 				ip_vs_proto_name(cp->protocol),
 				&cp->caddr.in6, ntohs(cp->cport),
 				&cp->vaddr.in6, ntohs(cp->vport),
 				&cp->daddr.in6, ntohs(cp->dport),
 				ip_vs_state_name(cp->protocol, cp->state),
-				(cp->timer.expires-jiffies)/HZ);
+				(cp->timer.expires-jiffies)/HZ, pe_data);
 		else
 #endif
 			seq_printf(seq,
 				"%-3s %08X %04X %08X %04X"
-				" %08X %04X %-11s %7lu\n",
+				" %08X %04X %-11s %7lu%s\n",
 				ip_vs_proto_name(cp->protocol),
 				ntohl(cp->caddr.ip), ntohs(cp->cport),
 				ntohl(cp->vaddr.ip), ntohs(cp->vport),
 				ntohl(cp->daddr.ip), ntohs(cp->dport),
 				ip_vs_state_name(cp->protocol, cp->state),
-				(cp->timer.expires-jiffies)/HZ);
+				(cp->timer.expires-jiffies)/HZ, pe_data);
 	}
 	return 0;
 }