ifplugd: code shrink; expanded comments

Signed-off-by: Maxim Kryzhanovsky <xmaks@email.cz>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/networking/ifplugd.c b/networking/ifplugd.c
index 373910863d7ea64108f51b7210ba293218719e1c..f398cca22bd48f0c12703d588d5f1e9c62394701 100644 (file)
--- a/networking/ifplugd.c
+++ b/networking/ifplugd.c
@@ -1,6 +1,6 @@
 /* vi: set sw=4 ts=4: */
 /*
- * ifplugd for busybox
+ * ifplugd for busybox, based on ifplugd 0.28 (written by Lennart Poettering).
  *
  * Copyright (C) 2009 Maksym Kryzhanovskyy <xmaks@email.cz>
  *
@@ -22,7 +22,11 @@
 #include <linux/wireless.h>
 
 /*
-TODO: describe compat status here.
+From initial port to busybox, removed most of the redundancy by
+converting implementation of a polymorphic interface to the strict
+functional style. The main role is run a script when link state
+changed, other activities like audio signal or detailed reports
+are on the script itself.
 
 One questionable point of the design is netlink usage:
 
@@ -500,38 +504,30 @@ static NOINLINE int check_existence_through_netlink(void)
 
                mhdr = (struct nlmsghdr*)replybuf;
                while (bytes > 0) {
-                       if (!NLMSG_OK(mhdr, bytes)
-                        || bytes < sizeof(struct nlmsghdr)
-                        || bytes < mhdr->nlmsg_len
-                       ) {
+                       if (!NLMSG_OK(mhdr, bytes)) {
                                bb_error_msg("netlink packet too small or truncated");
                                return -1;
                        }
 
                        if (mhdr->nlmsg_type == RTM_NEWLINK || mhdr->nlmsg_type == RTM_DELLINK) {
                                struct rtattr *attr;
-                               struct ifinfomsg *imsg;
                                int attr_len;
 
-                               imsg = NLMSG_DATA(mhdr);
-
                                if (mhdr->nlmsg_len < NLMSG_LENGTH(sizeof(struct ifinfomsg))) {
                                        bb_error_msg("netlink packet too small or truncated");
                                        return -1;
                                }
 
-                               attr = (struct rtattr*)((char*)imsg + NLMSG_ALIGN(sizeof(struct ifinfomsg)));
-                               attr_len = NLMSG_PAYLOAD(mhdr, sizeof(struct ifinfomsg));
+                               attr = IFLA_RTA(NLMSG_DATA(mhdr));
+                               attr_len = IFLA_PAYLOAD(mhdr);
 
                                while (RTA_OK(attr, attr_len)) {
                                        if (attr->rta_type == IFLA_IFNAME) {
-                                               char ifname[IFNAMSIZ + 1];
                                                int len = RTA_PAYLOAD(attr);
-
                                                if (len > IFNAMSIZ)
                                                        len = IFNAMSIZ;
-                                               memcpy(ifname, RTA_DATA(attr), len);
-                                               if (strcmp(G.iface, ifname) == 0) {
+
+                                               if (strncmp(G.iface, RTA_DATA(attr), len) == 0) {
                                                        G.iface_exists = (mhdr->nlmsg_type == RTM_NEWLINK);
                                                }
                                        }