ip-link: add switch to show human readable output

Byte and packet count can increase to really big numbers. This adds a
switch to show human readable output.

4: wl: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DORMANT group default qlen 1000
    link/ether 00:de:ad:be:ee:ef brd ff:ff:ff:ff:ff:ff
    RX: bytes  packets  errors  dropped overrun mcast
    1523846973 3969051  0       0       0       0
    TX: bytes  packets  errors  dropped carrier collsns
    8710088361 6077735  0       0       0       0
4: wl: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DORMANT group default qlen 1000
    link/ether 00:de:ad:be:ee:ef brd ff:ff:ff:ff:ff:ff
    RX: bytes  packets  errors  dropped overrun mcast
    1.5G       3.9M     0       0       0       0
    TX: bytes  packets  errors  dropped carrier collsns
    8.7G       6.0M     0       0       0       0

include/utils.h

@@ -11,6 +11,7 @@
 #include "rtm_map.h"
 
 extern int preferred_family;
+extern int human_readable;
 extern int show_stats;
 extern int show_details;
 extern int show_raw;

ip/ip.c

@@ -24,6 +24,7 @@
 #include "ip_common.h"
 
 int preferred_family = AF_UNSPEC;
+int human_readable = 0;
 int show_stats = 0;
 int show_details = 0;
 int resolve_hosts = 0;
@@ -47,6 +48,7 @@ static void usage(void)
 "                   tunnel | tuntap | maddr | mroute | mrule | monitor | xfrm |\n"
 "                   netns | l2tp | tcp_metrics | token | netconf }\n"
 "       OPTIONS := { -V[ersion] | -s[tatistics] | -d[etails] | -r[esolve] |\n"
+"                    -h[uman-readable] |\n"
 "                    -f[amily] { inet | inet6 | ipx | dnet | bridge | link } |\n"
 "                    -4 | -6 | -I | -D | -B | -0 |\n"
 "                    -l[oops] { maximum-addr-flush-attempts } |\n"
@@ -212,6 +214,9 @@ int main(int argc, char **argv)
 			preferred_family = AF_DECnet;
 		} else if (strcmp(opt, "-B") == 0) {
 			preferred_family = AF_BRIDGE;
+		} else if (matches(opt, "-human") == 0 ||
+			   matches(opt, "-human-readable") == 0) {
+			++human_readable;
 		} else if (matches(opt, "-stats") == 0 ||
 			   matches(opt, "-statistics") == 0) {
 			++show_stats;

man/man8/ip-link.8.in

@@ -16,6 +16,7 @@ ip-link \- network device configuration
 .ti -8
 .IR OPTIONS " := { "
 \fB\-V\fR[\fIersion\fR] |
+\fB\-h\fR[\fIuman-readable\fR] |
 \fB\-s\fR[\fItatistics\fR] |
 \fB\-r\fR[\fIesolve\fR] |
 \fB\-f\fR[\fIamily\fR] {
@@ -660,6 +661,12 @@ specifies what group of devices to show.
 .B up
 only display running interfaces.
 
+.SH "NOTES"
+Human readable values are calculated with SI prefixes, so with a decimal
+base, not binary. (This is unlike
+.BR ifconfig (8)
+, with uses binary prefix.) 1,000 bytes are 1 kB, 1,000 kB are 1 MB, ...
+
 .SH "EXAMPLES"
 .PP
 ip link show