: iproute2: enhance enforcement of ifconfig compatible address labels and allow non-compatible ones with -force

The ip addr command today rejects address labels that would break ifconfig. However, it allows some labels which still break it. Enhance enforcement to reject all known incompatible labels, and allow the existing -force option to allow someone to use a label even if it is not ifconfig compatible

Make existing -force option of ip addr add skip enforcment of ifconfig compatible address labels.
Change enforcement to properly reject labels that do begin with <devname> but are followed by a string that does not begin with colon.

The following changes since commit 4612d04d6b8f07274bd5d0688f717ccc189499ad:

tc class: Show class names from file (2015-03-15 12:27:40 -0700)

are available in the git repository at:

[email protected]:jharvell/iproute2.git addr-label-noncompat

for you to fetch changes up to 6a1d09e93ae1fb4f7f1cd5981813af918e8efc88:

Harvell <[email protected]> (2015-03-21 12:30:53 -0500)

----------------------------------------------------------------
Joe Harvell (5):
Making -force option of ip command also allow address labels that
are not backward-compatible with ifconfig. Note that even without this change the ip command does allow some incompatible address labels to be created. ifconfig depends on the labels beginning with <interface-name><colon>, but the ip command (even before the changes in this commit) only requires the prefix of the label to be <interface-name>. Thus, if you add a label such as eth0-media, it will be accepted by ip but ifconfig will barf on ifconfig -a. The motivation for this change is that the lenght allowed for a lable is small, so requiring a long prefix for ifconfig backwards compatibility limits the usefulness of the label. For embedded systems (or any system) where ifconfig is not even installed, it is useful to be able to create longer labels.
Enhancing enforcement of ifconfig compatible label. Prior
implementation allowed incompatible labels that started with dev but not dev:
Adding parentheses for clarity Removing code comment since it
is now clearly spelled out in fprintf error message
Using strncmp instead of matches for clarity and to avoid extra
strlen calls

 include/utils.h |  1 +
 ip/ip.c         |  2 ++
 ip/ipaddress.c  | 16 +++++++++++-----
 man/man8/ip.8   |  2 ++
 4 files changed, 16 insertions(+), 5 deletions(-)

index 9151c4f..e8a5467 100644
@@ -25,6 +25,7 @@ extern char * _SL_;
 extern int max_flush_loops;
 extern int batch_mode;
 extern bool do_all;
+extern bool require_ifconfig_compat;
 
 #ifndef IPPROTO_ESP
 #define IPPROTO_ESP    50

index da16b15..26f9910 100644
@@ -37,6 +37,7 @@ int force = 0;
 int max_flush_loops = 10;
 int batch_mode = 0;
 bool do_all = false;
+bool require_ifconfig_compat = true;
 
 struct rtnl_handle rth = { .fd = -1 };
 

@@ -246,6 +247,7 @@ int main(int argc, char **argv)
                        exit(0);
                } else if (matches(opt, "-force") == 0) {
                        ++force;
+                        require_ifconfig_compat = false;
                } else if (matches(opt, "-batch") == 0) {
                        argc--;
                        argv++;

index 99a6ab5..a131292 100644
@@ -1691,11 +1691,17 @@ static int ipaddr_modify(int cmd, int flags, int argc, char **argv)
                fprintf(stderr, "Not enough information: \"dev\" 

argument is required.\n");
                return -1;
        }

- if (l && matches(d, l) != 0) {
- fprintf(stderr, "\"dev\" (%s) must match \"label\" (%s).\n", d, l);
- return -1;
- }
-
+ if ( require_ifconfig_compat && l) {

+            bool isCompat = false;
+            size_t dLen = strlen(d);
+            size_t lLen = strlen(l);
+            if(lLen >= dLen && strncmp(d, l, dLen) == 0)

+ isCompat = (dLen == lLen || l[dLen] == ':');
+ if( !isCompat ) {
+ fprintf(stderr, "\"label\" (%s) must either be \"dev\" (%s) or start with \"dev\" followed by a colon (%s:).\n", l, d, d);
+ return -1;
+ }
+ }

        if (peer_len == 0 && local_len) {
                if (cmd == RTM_DELADDR && lcl.family == AF_INET && 

!(lcl.flags & PREFIXLEN_SPECIFIED)) {
fprintf(stderr,

index 016e8c6..3c3512c 100644
@@ -54,6 +54,8 @@ First failure will cause termination of ip.
 Don't terminate ip on errors in batch mode.
 If there were any errors during execution of the commands, the 

application return code will be non zero.

+This option also allows creation of address labels that may not be backwards compatible with ifconfig. +
.TP
.BR "\-s" , " \-stats" , " \-statistics"
Output more information. If the option