iplink: support add/delete

function                                             old     new   delta
do_change                                              -     490    +490
.rodata                                           135193  135225     +32
do_iplink                                           1146    1169     +23
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 2/0 up/down: 545/0)             Total: 545 bytes

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

1 files changed, 91 insertions, 2 deletions

diff --git a/networking/libiproute/iplink.c b/networking/libiproute/iplink.c
index df8a354a1..a28df6e79 100644
--- a/networking/libiproute/iplink.c
+++ b/networking/libiproute/iplink.c
@@ -283,11 +283,98 @@ static int ipaddr_list_link(char **argv)
         return ipaddr_list_or_flush(argv, 0);
 }
 
+#ifndef NLMSG_TAIL
+#define NLMSG_TAIL(nmsg) \
+        ((struct rtattr *) (((void *) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))
+#endif
+/* Return value becomes exitcode. It's okay to not return at all */
+static int do_change(char **argv, const unsigned rtm)
+{
+        static const char keywords[] ALIGN1 =
+                "link\0""name\0""type\0""dev\0";
+        enum {
+                ARG_link,
+                ARG_name,
+                ARG_type,
+                ARG_dev,
+        };
+        struct rtnl_handle rth;
+        struct {
+                struct nlmsghdr         n;
+                struct ifinfomsg        i;
+                char                    buf[1024];
+        } req;
+        int arg;
+        char *name_str = NULL, *link_str = NULL, *type_str = NULL, *dev_str = NULL;
+
+        memset(&req, 0, sizeof(req));
+
+        req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
+        req.n.nlmsg_flags = NLM_F_REQUEST;
+        req.n.nlmsg_type = rtm;
+        req.i.ifi_family = preferred_family;
+        if (rtm == RTM_NEWLINK)
+                req.n.nlmsg_flags |= NLM_F_CREATE|NLM_F_EXCL;
+
+        while (*argv) {
+                arg = index_in_substrings(keywords, *argv);
+                if (arg == ARG_link) {
+                        NEXT_ARG();
+                        link_str = *argv;
+                } else if (arg == ARG_name) {
+                        NEXT_ARG();
+                        name_str = *argv;
+                } else if (arg == ARG_type) {
+                        NEXT_ARG();
+                        type_str = *argv;
+                } else {
+                        if (arg == ARG_dev) {
+                                if (dev_str)
+                                        duparg(*argv, "dev");
+                                NEXT_ARG();
+                        }
+                        dev_str = *argv;
+                }
+                argv++;
+        }
+        xrtnl_open(&rth);
+        ll_init_map(&rth);
+        if (type_str) {
+                struct rtattr *linkinfo = NLMSG_TAIL(&req.n);
+
+                addattr_l(&req.n, sizeof(req), IFLA_LINKINFO, NULL, 0);
+                addattr_l(&req.n, sizeof(req), IFLA_INFO_KIND, type_str,
+                                strlen(type_str));
+                linkinfo->rta_len = (void *)NLMSG_TAIL(&req.n) - (void *)linkinfo;
+        }
+        if (rtm != RTM_NEWLINK) {
+                if (!dev_str)
+                        return 1; /* Need a device to delete */
+                req.i.ifi_index = xll_name_to_index(dev_str);
+        } else {
+                if (!name_str)
+                        name_str = dev_str;
+                if (link_str) {
+                        int idx = xll_name_to_index(link_str);
+                        addattr_l(&req.n, sizeof(req), IFLA_LINK, &idx, 4);
+                }
+        }
+        if (name_str) {
+                const size_t name_len = strlen(name_str) + 1;
+                if (name_len < 2 || name_len > IFNAMSIZ)
+                        invarg(name_str, "name");
+                addattr_l(&req.n, sizeof(req), IFLA_IFNAME, name_str, name_len);
+        }
+        if (rtnl_talk(&rth, &req.n, 0, 0, NULL, NULL, NULL) < 0)
+                return 2;
+        return 0;
+}
+
 /* Return value becomes exitcode. It's okay to not return at all */
 int do_iplink(char **argv)
 {
         static const char keywords[] ALIGN1 =
-                "set\0""show\0""lst\0""list\0";
+                "add\0""delete\0""set\0""show\0""lst\0""list\0";
         int key;
         if (!*argv)
                 return ipaddr_list_link(argv);
@@ -295,7 +382,9 @@ int do_iplink(char **argv)
         if (key < 0)
                 bb_error_msg_and_die(bb_msg_invalid_arg, *argv, applet_name);
         argv++;
-        if (key == 0) /* set */
+        if (key <= 1) /* add/delete */
+                return do_change(argv, key ? RTM_DELLINK : RTM_NEWLINK);
+        else if (key == 2) /* set */
                 return do_set(argv);
         /* show, lst, list */
         return ipaddr_list_link(argv);