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45 lines
1.5 KiB
Plaintext
45 lines
1.5 KiB
Plaintext
This document is meant to convince you to not use ifup/ifdown.
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The general problem with ifupdown is that it is "copulated in vertical
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fashion" by design. It tries to do the job of shell script in C,
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and this is invariably doomed to fail. You need ifup/ifdown
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to be adaptable by local admins, and C is an extremely poor choice
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for that.
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We are doomed to have problems with ifup/ifdown. Just look as this code:
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static const struct dhcp_client_t ext_dhcp_clients[] = {
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{ "dhcpcd", "<up cmd>", "<down cmd>" },
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{ "dhclient", ........ },
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{ "pump", ........ },
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{ "udhcpc", ........ },
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};
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static int dhcp_down(struct interface_defn_t *ifd, execfn *exec)
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{
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#if ENABLE_FEATURE_IFUPDOWN_EXTERNAL_DHCP
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int i ;
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for (i = 0; i < ARRAY_SIZE(ext_dhcp_clients); i++) {
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if (exists_execable(ext_dhcp_clients[i].name))
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return execute(ext_dhcp_clients[i].stopcmd, ifd, exec);
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}
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bb_error_msg("no dhcp clients found, using static interface shutdown");
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return static_down(ifd, exec);
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#elif ENABLE_UDHCPC
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return execute("kill "
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"`cat /var/run/udhcpc.%iface%.pid` 2>/dev/null", ifd, exec);
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#else
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return 0; /* no dhcp support */
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#endif
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}
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How the hell it is supposed to work reliably this way? Just imagine that
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admin is using pump and ifup/ifdown. It works. Then, for whatever reason,
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admin installs dhclient, but does NOT use it. ifdown will STOP WORKING,
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just because it will see installed dhclient binary in e.g. /usr/bin/dhclient!
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This is stupid.
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I seriously urge people to not use ifup/ifdown.
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Use something less brain damaged.
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