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053c095a82
Contrary to common expectations for an "int" return, these functions
return only a positive value -- if used correctly they cannot even
return 0 because the message header will necessarily be in the skb.
This makes the very common pattern of
if (genlmsg_end(...) < 0) { ... }
be a whole bunch of dead code. Many places also simply do
return nlmsg_end(...);
and the caller is expected to deal with it.
This also commonly (at least for me) causes errors, because it is very
common to write
if (my_function(...))
/* error condition */
and if my_function() does "return nlmsg_end()" this is of course wrong.
Additionally, there's not a single place in the kernel that actually
needs the message length returned, and if anyone needs it later then
it'll be very easy to just use skb->len there.
Remove this, and make the functions void. This removes a bunch of dead
code as described above. The patch adds lines because I did
- return nlmsg_end(...);
+ nlmsg_end(...);
+ return 0;
I could have preserved all the function's return values by returning
skb->len, but instead I've audited all the places calling the affected
functions and found that none cared. A few places actually compared
the return value with <= 0 in dump functionality, but that could just
be changed to < 0 with no change in behaviour, so I opted for the more
efficient version.
One instance of the error I've made numerous times now is also present
in net/phonet/pn_netlink.c in the route_dumpit() function - it didn't
check for <0 or <=0 and thus broke out of the loop every single time.
I've preserved this since it will (I think) have caused the messages to
userspace to be formatted differently with just a single message for
every SKB returned to userspace. It's possible that this isn't needed
for the tools that actually use this, but I don't even know what they
are so couldn't test that changing this behaviour would be acceptable.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
153 lines
4.5 KiB
C
153 lines
4.5 KiB
C
/*
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* Netlink interface for IEEE 802.15.4 stack
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*
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* Copyright 2007, 2008 Siemens AG
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* Written by:
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* Sergey Lapin <slapin@ossfans.org>
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* Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
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* Maxim Osipov <maxim.osipov@siemens.com>
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*/
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#include <linux/kernel.h>
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#include <linux/gfp.h>
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#include <net/genetlink.h>
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#include <linux/nl802154.h>
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#include "ieee802154.h"
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static unsigned int ieee802154_seq_num;
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static DEFINE_SPINLOCK(ieee802154_seq_lock);
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struct genl_family nl802154_family = {
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.id = GENL_ID_GENERATE,
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.hdrsize = 0,
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.name = IEEE802154_NL_NAME,
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.version = 1,
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.maxattr = IEEE802154_ATTR_MAX,
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};
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/* Requests to userspace */
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struct sk_buff *ieee802154_nl_create(int flags, u8 req)
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{
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void *hdr;
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struct sk_buff *msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
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unsigned long f;
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if (!msg)
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return NULL;
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spin_lock_irqsave(&ieee802154_seq_lock, f);
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hdr = genlmsg_put(msg, 0, ieee802154_seq_num++,
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&nl802154_family, flags, req);
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spin_unlock_irqrestore(&ieee802154_seq_lock, f);
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if (!hdr) {
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nlmsg_free(msg);
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return NULL;
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}
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return msg;
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}
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int ieee802154_nl_mcast(struct sk_buff *msg, unsigned int group)
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{
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struct nlmsghdr *nlh = nlmsg_hdr(msg);
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void *hdr = genlmsg_data(nlmsg_data(nlh));
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genlmsg_end(msg, hdr);
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return genlmsg_multicast(&nl802154_family, msg, 0, group, GFP_ATOMIC);
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}
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struct sk_buff *ieee802154_nl_new_reply(struct genl_info *info,
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int flags, u8 req)
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{
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void *hdr;
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struct sk_buff *msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
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if (!msg)
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return NULL;
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hdr = genlmsg_put_reply(msg, info,
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&nl802154_family, flags, req);
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if (!hdr) {
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nlmsg_free(msg);
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return NULL;
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}
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return msg;
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}
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int ieee802154_nl_reply(struct sk_buff *msg, struct genl_info *info)
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{
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struct nlmsghdr *nlh = nlmsg_hdr(msg);
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void *hdr = genlmsg_data(nlmsg_data(nlh));
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genlmsg_end(msg, hdr);
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return genlmsg_reply(msg, info);
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}
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static const struct genl_ops ieee8021154_ops[] = {
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/* see nl-phy.c */
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IEEE802154_DUMP(IEEE802154_LIST_PHY, ieee802154_list_phy,
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ieee802154_dump_phy),
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IEEE802154_OP(IEEE802154_ADD_IFACE, ieee802154_add_iface),
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IEEE802154_OP(IEEE802154_DEL_IFACE, ieee802154_del_iface),
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/* see nl-mac.c */
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IEEE802154_OP(IEEE802154_ASSOCIATE_REQ, ieee802154_associate_req),
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IEEE802154_OP(IEEE802154_ASSOCIATE_RESP, ieee802154_associate_resp),
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IEEE802154_OP(IEEE802154_DISASSOCIATE_REQ, ieee802154_disassociate_req),
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IEEE802154_OP(IEEE802154_SCAN_REQ, ieee802154_scan_req),
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IEEE802154_OP(IEEE802154_START_REQ, ieee802154_start_req),
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IEEE802154_DUMP(IEEE802154_LIST_IFACE, ieee802154_list_iface,
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ieee802154_dump_iface),
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IEEE802154_OP(IEEE802154_SET_MACPARAMS, ieee802154_set_macparams),
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IEEE802154_OP(IEEE802154_LLSEC_GETPARAMS, ieee802154_llsec_getparams),
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IEEE802154_OP(IEEE802154_LLSEC_SETPARAMS, ieee802154_llsec_setparams),
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IEEE802154_DUMP(IEEE802154_LLSEC_LIST_KEY, NULL,
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ieee802154_llsec_dump_keys),
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IEEE802154_OP(IEEE802154_LLSEC_ADD_KEY, ieee802154_llsec_add_key),
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IEEE802154_OP(IEEE802154_LLSEC_DEL_KEY, ieee802154_llsec_del_key),
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IEEE802154_DUMP(IEEE802154_LLSEC_LIST_DEV, NULL,
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ieee802154_llsec_dump_devs),
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IEEE802154_OP(IEEE802154_LLSEC_ADD_DEV, ieee802154_llsec_add_dev),
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IEEE802154_OP(IEEE802154_LLSEC_DEL_DEV, ieee802154_llsec_del_dev),
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IEEE802154_DUMP(IEEE802154_LLSEC_LIST_DEVKEY, NULL,
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ieee802154_llsec_dump_devkeys),
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IEEE802154_OP(IEEE802154_LLSEC_ADD_DEVKEY, ieee802154_llsec_add_devkey),
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IEEE802154_OP(IEEE802154_LLSEC_DEL_DEVKEY, ieee802154_llsec_del_devkey),
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IEEE802154_DUMP(IEEE802154_LLSEC_LIST_SECLEVEL, NULL,
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ieee802154_llsec_dump_seclevels),
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IEEE802154_OP(IEEE802154_LLSEC_ADD_SECLEVEL,
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ieee802154_llsec_add_seclevel),
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IEEE802154_OP(IEEE802154_LLSEC_DEL_SECLEVEL,
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ieee802154_llsec_del_seclevel),
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};
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static const struct genl_multicast_group ieee802154_mcgrps[] = {
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[IEEE802154_COORD_MCGRP] = { .name = IEEE802154_MCAST_COORD_NAME, },
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[IEEE802154_BEACON_MCGRP] = { .name = IEEE802154_MCAST_BEACON_NAME, },
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};
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int __init ieee802154_nl_init(void)
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{
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return genl_register_family_with_ops_groups(&nl802154_family,
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ieee8021154_ops,
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ieee802154_mcgrps);
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}
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void ieee802154_nl_exit(void)
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{
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genl_unregister_family(&nl802154_family);
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}
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